Reconstructive surgery after surgical treatment of neoplasms in the head and neck region is always a challenge. Many factors are responsible for the success of reconstruction. The anatomy of the facial region is complex, which significantly influences the aesthetic effect of the reconstruction. Moreover, many patients undergo postoperative radiotherapy after surgical treatment, which affects the range of reconstructive techniques. The aim of this study is to review current reconstructive methods in the craniofacial region, using bone-anchored implants to attach nasal prostheses. The article also comprises the authors’ own experience with successful single-stage, Vistafix 3 osseointegrated implants for the attachment of an external nasal prosthesis in a 51-year-old man after surgical removal of squamous cell carcinoma of the nose and paranasal sinuses. The literature search for articles regarding implants in craniofacial reconstructions was performed using the three following databases: Scopus, Web of Science and MEDLINE (through PubMed), and follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA). A systematic literature search was set for 2018–2023 and retrieved 92 studies. From them, 18 articles were included in the review. Malignant neoplasms of paranasal sinuses account for 3–5% of tumors detected in the head and neck region ,2. SquamRadical surgical treatment requires extensive tumor removal leading to permanent deformities in the midface. The operation leads to dysfunction of the nose and sinuses, but also to large aesthetic defects, preventing the patient from returning to social life. Reconstructive surgery in the facial region poses many difficulties. Pedicle flaps displaced from the surrounding regions of the face do not have a favourable effect due to their unsatisfactory cosmetic effect but also due to additional facial scarring at the site where the flap was taken. Transplantation using the patient’s own tissues often proves impossible because the structure of the nose is made up of histologically diverse tissues, i.e., bone, cartilage, skin and the subcutaneous layer or muscle tissue, making it impossible to fully recreate the anatomy of this region. Therefore, increasingly perfect methods are being sought to design prosthetic craniofacial elements. Until recently, patients could only be offered prostheses mounted on spectacles, the use of which was not comfortable for the patient.The aim of this article is to review current reconstructive methods in the craniofacial region, using bone-anchored implants to attach nasal prostheses. The article also describes the authors’ own experience with the first Polish successful application of single-stage, third-generation Vistafix osseointegrated implants for the attachment of an external nasal prosthesis in a 51-year-old man after surgical removal of squamous cell carcinoma of the nose and paranasal sinuses.This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA).The literature search for articles regarding implants in craniofacial reconstructions was performed using the three following databases: Scopus, Web of Science and MEDLINE (through PubMed). The last search was conducted on 15 May 2023, in each of the databases. It was not necessary to contact the authors of the retrieved research articles for additional information. Time descriptors had been set for 2018–2023. Only original research articles, case studies and reviews concerning nasal reconstruction and published in English were included. Book chapters, conference papers and opinions were excluded. Duplicates were removed using the automatic EndNote 20 duplicate finder, followed by a manual search.A systematic literature search retrieved 92 studies. From 92 records, 18 articles were included in the review. Details regarding the selection process are summarized in a custom-built PRISMA flow chart in Due to the poor cosmetic and functional effect of the spectacle-mounted nasal prostheses, more stable methods of prosthetic attachment are being sought. For several years, titanium implants screwed into the temporal bones have been used to reconstruct auricular deformities. Similar solutions have also been attempted in other regions of the face, such as orbit .Originally, the basis of craniofacial prostheses was the original Brånemark implant, which has been modified over the years. Nowadays, since 2010, self-tapping implants in unchanged form have supported Vistafix System craniofacial implants  as well as Bone Anchored Hearing Aid (BAHA) and Active Osseointegrated Steady-State Implant System (OSI) hearing aids manufactured by Cochlear.The Vistafix System is a craniofacial prosthesis, built from a few self-tapping titanium implants that are anchored to the bone during a surgical procedure. A durable and stable solution achieved in such way is used by a prosthetist for the creation of a trabecular scaffold—substratum for acrylic and silicone prosthesis. Thanks to the available techniques and the advanced abilities of prosthetics specialists, prostheses are created in a unique manner, with imprinting of a patient’s personal characteristics . There are isolated reports in the literature on the effects of using anchored implants in prosthetics of the external nose. It has to be emphasized that in the midfacial region, the effective anchoring of an implant is more challenging for a surgeon than in a temporal bone. It is primarily caused by a significantly thinner bone in the middle part of the craniofacial region as well as the complicated shapes of bones in this anatomical region. Additionally, the vicinity of important anatomical structures, i.e., eyeballs, the brain, cranial nerves and large vessels, is relevant.The system of craniofacial implants allows for prostheses to be designed for defects in three primary regions: ear, eye and nose. The main recipients of the solution shall be the patients who require rehabilitation after oncological treatment, injuries, burns or congenital defects. An indicator for contemplation of such prosthetics is extensive facial deformities, particularly when the possibility of reconstructive plastic surgery is limited or there are contraindications for general anaesthetics, as the implantation can be performed under the local one.This method offers high aesthetic effects depending mainly on the quality of the prosthesis and it supports a comfortable rehabilitation process . A prostAdhesion of the prosthesis to the face is determined by the number of anchored implants and their stability in the patient’s bone. The prosthesis can also provide support for corrective spectacles or sunglasses. It is also worth noting that facial prostheses fixed on anchored implants are tolerated better than adhesively fixed implants and, therefore, provide a greater improvement in patients’ quality of life ,26.It is assumed that the optimum number for prosthetic nasal defects is three implants, which represent three points of attachment of the trabecular prosthetic structure. During qualification, it is crucial to perform a CT scan of the prosthetic area in order to be able to assess the quality and thickness of the bone necessary for the insertion of self-tapping implants. The titanium implants of the third generation Vistafix system  have a diameter of 4.475 mm and are screwed in 3 or 4 mm deep. In our experience, however, the use of two Vistafix implants inserted into the alveolar bone of the maxilla also offers the possibility of stable fixation of the nasal prosthesis and its adhesion, although less tight compared to the three points of support.Tso et al. described a case of external nasal reconstruction using Zygan Southern Implants titanium implants, which were mounted in two zygomatic bones, guided through the maxilla . One of Some reconstructive techniques of craniofacial deformities caused by non-Hodgkin’s lymphoma have been described. Osseointegrated implants are not used due to the aggressive nature of the tumor. Mainly magnets and tich buttons are used to attach the nasal prostheses .The process of osseointegration of the cells on the surface of the titanium implant is central to the success of the implant and prosthetic surgery.Absolute contraindications for implantation are a lack of oncological radicality and a patient’s condition that prevents proper implant hygiene due to severe mental disorders , cachexia, drug or alcohol addiction or a disability that makes it impossible to put on, take off and take care of the hygiene of the prosthesis. Relative contraindications are mild psychiatric disorders and poor craniofacial bone condition.The basics of the implant procedure were already defined by Brånemark (first implant procedure in 1979). The implantation process is carried out in several stages.-bone parameters—thickness and shape,-implant stability,-minimizing the impact of unwanted forces on the implants,-planning locations for replacement implants in case of implant failure at the originally selected sites, and-maintaining the angles at which the implants are inserted so that other prosthetic components can subsequently be fixed to them.During the planning and qualification of the patient for such an operation, attention must be paid to the condition of the bone in which the implants are planned to be fitted. It is also very important to cooperate with a prosthetist, so that together they can plan the best location for the implants, both in terms of the stability in the bone and the fitting of the prosthesis. This is why several specialists are involved in the surgical planning stage: surgeons, clinical engineers, prosthetists and radiologists . Pre-opeNowadays, computer-aided design and manufacturing (CAD/CAM) are increasingly being used for this purpose. They allow implants to be virtually positioned in potential locations or models corresponding to the implanted fragments to be created and then printed using 3D technology for prior training ,31.During the patient’s qualification visit, the etiology of the defect  is taken into account. The site and method of prosthetic placement are determined, assuming a single- or two-stage operation, as well as the initial number of points required for stable mounting of the prosthesis.The surgical treatment time depends on the number of surgical stages and loading time of the implant with an additional structural element such as the abutment, as well as the patient’s time of recovery. The completion of the surgical part is approx. two months after the last operation. This is the time when the skin around the implant should have completely healed. This will guarantee that the created prosthesis will fit well with the patient’s body.Single-stage surgery can be opted for under a few conditions: when the bone is of good quality, the implant has been screwed correctly, the stability of the implant has been confirmed via Resonance Frequency Analysis (RFA) and a correct osseointegration process is expected. Single-stage surgery is most commonly used in prosthetic procedures for auricular defects.-longer time required for soft tissue healing;-simultaneous removal of oncological lesions and insertion of anchored implants;-planned radiotherapy treatment.Two-stage surgery is recommended if we expect a slower osseointegration process, in cases such as the following:If the operation is performed in a two-stage process, after insertion of the implant, a safety screw is tightened instead of the abutment, which emerges through the skin in a single-stage operation, and it serves to prevent contamination of the thread. Subsequently, the secured implant is sutured under the skin until the abutment is loaded. After a few months—minimum 3 months ,32,33—th-taking an impression of the area for the prosthesis,-fitting of the external structure developed from archival photographs of the patient’s face,-modelling the prosthesis in wax to obtain its final shape, and-acceptance of the prosthesis, learning to use the system.The prosthetic part consists of the manufacturing and fitting of the prosthesis, individually to the patient, and starts around 7–8 weeks after implantation, once the soft tissue swelling has subsided. The prosthesis is moldable and adaptable to the correct shape and allows color matching to resemble the patient’s skin. It is made of silicone based on an acrylic plate, and the manufacturing process consists of four stages:Modern technical methods make it increasingly possible to replace hand-made prostheses with ones manufactured using 3D printing. However, a prosthesis created in this way may have less precision in adhering to the patient’s face. The problem mainly relates to marginal adaptation, which is caused by a too-thick material layer of 0.4 mm, meaning a serious limitation of the prosthesis printing technique compared to a thickness of less than 0.1 mm in conventional prostheses . ImproveAn important parameter that is relevant to the effects of implantation is the radiation dose received by the craniofacial region during radiotherapy . Most reTwo to three anchorage points are required for the creation and good embedding of the prosthesis. The load and strength of each implant depend on their interposition, as well as the thickness of the bone into which they are inserted. Substrate factors are extremely important for proper osseointegration: bone quality, its density, vascularization, anatomical shape  as well The craniofacial region, particularly the midface, presents a surgical challenge for implant insertion.As indicated in the literature, implants placed in the temporal bone area have a better prognosis of survival and fewer complications compared to other areas of the skull . The higIt is known that aging negatively affects organ function. The age at which osseointegration can be performed may vary depending on the specific procedure and the individual’s overall health. While osseointegration is possible at various ages, there are a few factors to consider such as bone density and quality, healing capacity and also systemic conditions.Age-associated natural decline in bone density and quality can affect the ability of the bone to fuse with the implant. However, factors such as overall bone health and the specific condition of the patient’s bones will play a significant role. Tissue aging was investigated by some authors . In a feSubcutaneous tissue reduction and split skin grafts are important in surgical aftercare. Over the years, clip repairs, fabrication of new prostheses, repair of the superstructure and fabrication of a new superstructure are needed . The maiIn December 2021, in the Clinic of Otolaryngology CMKP in Warsaw, the first Polish single-stage procedure involving the placement of Vistafix 3 system titanium implants was successfully performed. The procedure led to effective fixation of a nasal prosthesis in a patient after the total amputation of the external nose and the anterior wall of the frontal sinus caused by squamous cell carcinoma of the maxilloethmoidal massif.Ten months earlier, in February 2021, a 51-year-old patient was admitted to the clinic due to recurrent nosebleeds and a change in the shape of his external nose. Physical examination revealed a collapsed saddle nose and perforation of the nasal septum. A craniofacial CT scan confirmed a tumour of the nasal septum, bilaterally infiltrating the anterior ethmoid cells and frontal sinuses a. HistopThe surgery was performed as a single-stage one. The thickness of the skin in the areas designated for the implants was measured in order to select the optimal length of the abutment (range between 3.5 mm to 7.5 mm) . The skiSubsequently, soft tissue abrading was performed simultaneously to minimize the risk of skin flap displacement around the abutment and was followed by a skin thickness measurement . The optTwo implants were fitted just below the bottom edge of the piriform aperture in the right and left upper jaws. The surgery was preceded by the process of computer planning the placement of implants and determining their location in relation to soft tissues and taking into account the aesthetic effects we want to achieve a–c. Due The key element was to orient the implants at the proper angle: perpendicular to the bone, while at the same time optimal for further affixation of the prosthetic. This allowed maximum utilization of the bone surface and better mechanical stability, as well as facilitating the creation of a supporting structure for the actual prosthesis in subsequent prosthetic stages.One week after the operation, the sutures were removed, and six weeks later, the implants were loaded with abutments and the patient was referred to the prosthetic laboratory. The total time from implant surgery to the placement of the final prosthesis was 14 weeks. The patient received a silicone prosthesis with an acrylic bearing part, in which the clips that fix it in place were embedded, as well as a trabecular scaffold, individually developed according to the patient’s anatomical features and the location of the anchored implants. The prosthesis is ultimately successfully supported by two implants embedded in the maxilla at the base of the nose.At a follow-up visit 12 months after the operation, both the patient and the surgeon spoke very highly of the cosmetic effect of the prosthesis, which allowed the patient to return to full social function . The pro2, this is the optimal method with good results [Surgical treatment of tumours of the maxilloethmoidal massif consists of two stages—a stage of resection of the pathological lesion and a stage of reconstruction to fill the defect and restore the best possible function of the nose and sinuses. Reconstructive possibilities depend on a lot of factors, the most important being the location and extent of the defect. Autological reconstruction with cartilage, muscle, subcutaneous tissue and skin grafts are attempted to fill the defect of the external nose. Due to the complexity of the external nose, this reconstruction is always challenging and sometimes becomes impossible to perform. For small facial defects up to 1 cm results . The use results ,45. Unfo results ,44,46. B results . AdditioThe Titanium Plate System “Epiplating” for Osseo-integrated Bone Anchorage of Craniofacial Prosthesis is an alternative system . It consThere are also titanium basal implants ; they are also used in craniofacial reconstructions. They consist of a cylindrical part and a larger, cortically anchored base plate. Unlike traditional root-form implants , which are inserted vertically and primarily designed to be supported by trabecular bone, these implants are inserted from the lateral aspect of the host bone, providing multicortical support. Implants possess one to three very pronounced “threads“ or “base-plates”, which are securely anchored in the cortical bone, a bone area which is more stable during the remodelling/resorption process and which can respond successfully to immediate loading protocols. The site of force transmission is far away from the site of bacterial invasion, allowing for early loading and resistance to infection. In Konstantinović et al.’s study, the survival rate of basal implants used for the retention of extraoral prostheses was assessed . The oveA non-invasive, widely used method of covering facial defects is silicone nasal prostheses mounted on spectacles or attached to the skin with silicone-based adhesives. The prosthesis is removed along with the glasses, giving easy access to inspect the post-operative wound, but its unstable fixation makes it significantly more difficult for a patient to return to social life. Loose attachment of the prosthesis to the face causes exhaled air to escape around the prosthesis, exposing the facial defects. The high risk of the prosthesis shifting and slipping when mounted on glasses causes patients to have limitations in physical activities, sports and some occupations, making it often difficult to accept . It is aRecent technical advances have allowed the introduction of further solutions in the reconstruction of defects in the midface, which are titanium implants anchored in the bone, allowing effective and stable fixation of the silicone prosthesis. These implants are subject to further improvements. According to studies, third-generation Vistafix facial implants have higher stability compared to earlier generations  and haveThe modification of the operation to a single-stage procedure that we performed in our clinic twice shortened the time needed for final fixation of the prosthesis, which was 14 weeks instead of 6–8 months for a two-stage operation ,51.The case we presented also confirms the possibility of stable fixation of the prosthesis on two 4 mm long implants placed at the anterior nasal floor, which is the most commonly used location for this type of reconstruction . Two impIn addition to the aesthetic benefits, significant advantages of this method of reconstruction are the improvement in the articulation of the patient’s speech, resulting in better verbal contact; protection of the upper respiratory tract against aspiration of foreign bodies and easy oncological control.We would like to emphasise that implants do not conflict with plastic reconstructive methods and can often be used complementarily or as a temporary tool prior to surgical reconstruction (temporary provision). This is especially important for patients who have had their external nose removed, where a comprehensive reconstruction can only be carried out after two years, when the risk of recurrence is significantly reduced . ImplantThe results of the studies included in this review are limited by the relatively small number of patients sampled for the studies, allowing only qualitative analysis. Within the limitations of this study are the small groups of patients with various types of implants, the limited number of adequate studies and the fact that patients who were qualified for nose reconstruction had undergone oncological operations of various scope, which significantly affected later possibilities of choosing the implantation site and, thus, the prognosis as to the maintenance of implants. This is similar to our patient, for whom the scope of the operation was so extensive that we were not able to place the third implant properly.Anchored craniofacial implants are a good and minimally invasive solution for postnasal resection patients with a low rate of adverse reactions. In selected clinical cases, stable fixation of the prosthesis on two anchored implants is possible and their single-step implantation significantly speeds up the prosthetic process.


He had a history of psychotic disorders and inserting an ink chamber of a pen into the urethra. Imaging showed hydronephrosis and a large urinary stone in the bladder with no sign of foreign body. During open cystotomy, we found that bladder stone was attached to a plastic tube that was extended into the patient's urethra. In such cases, timely surgery to prevent urinary retention and psychological support are required.Several self-inserted foreign bodies have been reported in the lower genitourinary system. We report a 27-year-old man with suprapubic severe pain, purulent discharge from the urethra Imaging is necessary to detect the position, shape, and size of foreign bodies .Here, we report a male patient with transurethral self-insertion of the ink chamber of a pen into the urethra which caused a large calculus formation in the bladder.Case presentation:, and dribbling was referred to a tertiary private clinic in Golpaygan, Iran. He declared a history of psychotic disorders and initiation of the signs after he attempted to insert a pen tube into the urethra. Laboratory examination confirmed a severe urinary tract infection (UTI) and creatinine equal to 2. X-ray and CT scan showed a large urinary stone in the bladder occupying almost all of the intravesical space with no sign of foreign object (A 27-year-old man with the chief complaint of suprapubic severe pain, purulent discharge from the urethran object , Fig. 2BAfter opening the bladder during the surgical procedure, we discovered that the bladder stone was attached to a plastic tube that was extended into the patient's urethra . AccordiTwo days later, the patient was discharged in good general condition. The patient followed for checking the recovery status after surgery after 3 months. He had no pain or any sign of urethral obstruction and urinary retention. Blood examinations including UA, UC, and creatinine were normal. Control sonography showed no sign of hydronephrosis or complications such as a urethral stricture. The patient was referred to a psychology clinic to prevent other probable problems.Written informed consent was obtained from the patient for the publication of the collection of his clinical data.2Mostly, foreign bodies have been reported in the respiratory and gastrointestinal systems, but there is limited literature on the case of the lower urinary system. including case reports and small case series and there is a lack of data regarding management and epidemiology in this regard . Some ofDayron Rodríguez et al., in 2020 showed that genitourinary foreign bodies have a crucial burden on healthcare systems. They found that they occurred frequently in younger female patients but penile and urethral/bladder foreign objects are more frequent in older men and were related to longer hospital admission days and costs .Some behaviors such as autoerotic stimulation, intoxication, senility, Psychosis With or Without Mood Disturbance, Cognitive Disorders, Malingering, and stash of drug through the urethra into the bladder to escape prosecution are reported as the cause of the self-insertion of foreign objects . Even, aAlmost one-third of male patients who suffered urethra/bladder foreign bodies had a history of major mental disorders . In addiMost foreign objects in the urinary system can be removed endoscopically but in the case of our patient, open surgical removal was necessary due to the large calculi formation in the bladder.Urethral stenosis is common after the removal of foreign objects because of tissue injury; therefore, antibiotics and tetanus prophylaxis are essential after surgical interventions .Foreign bodies in the bladder are the main risk factor for larger bladder stones. Any foreign body that makes its way into the bladder can act as scaffolding for calculus construction. The formation of stones is a step-by-step mechanism that has been well presented in the literature . Also, tThree reasons are described for the miss-diagnosis of self-inserted urethral foreign bodies. The first reason is the rare occurrence of this situation. Second is not having a correct history of the disease due to the unwillingness of patients to give information and third is the inefficiency of simple X-ray imaging to detect radiolucent objects . Althoug3trans-urethral ink chamber of a pen leading to a large stone formation in his bladder. Timely removal of the stone prevented bladder outlet obstruction and reversed hydronephrosis. Psychological counseling and psychotherapy can be effective in preventing the recurrence of such cases.The presented patient in this report was a case of self-inserted All authors listed have significantly contributed to the investigation, development and writing of this article. </p>This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.No data was used for the research described in the article.No additional information is available for this paper.The authors declare no competing interests.


The COVID-19 pandemic presents an unprecedented clinical and healthcare challenge for the many medical researchers who are attempting to prevent its worldwide spread. It also presents a challenge for statisticians involved in designing appropriate sampling plans to estimate the crucial parameters of the pandemic. These plans are necessary for monitoring and surveillance of the phenomenon and evaluating health policies. In this respect, we can use spatial information and aggregate data regarding the number of verified infections  to improve the standard two-stage sampling design broadly adopted for studying human populations. We present an optimal spatial sampling design based on spatially balanced sampling techniques. We prove its relative performance analytically in comparison to other competing sampling plans, and we also study its properties through a series of Monte Carlo experiments. Considering the optimal theoretical properties of the proposed sampling plan and its feasibility, we discuss suboptimal designs that approximate well optimality and are more readily applicable. The SARS-CoV-2 pandemic has affected Western countries suddenly and in a devastating manner. The presence of many mutations of the virus after the first 2020 wave of the pandemic, together with possible future new pandemic emergencies, makes it essential to establish a system of timely monitoring and surveillance tools. The phenomenon has already been analysed in an extensive scientific literature which proposes various methods for the analysis of the COVID-19 pandemic. Italy was the first European nation to host an outbreak during the month of February 2020  denoted as , with Let us consider a target population l et al. , p. 116,Our proposed sample design can be illustrated as follows.S from U using a two-stage random sampling design without replacement. According to the specific sampling context, the primary sample units (PSUs) may correspond to different levels of aggregations, e.g., municipalities or census enumeration areas.First, we select a sample The sampling process starts with drawing a first-stage sample of clusters, A second-stage sample, say As a consequence, the final inclusion probability of person self-weighting  method , respectively, which enable the selection of unequal probability samples of fixed size that are well spread over the population. Both algorithms use the distance between the population units to create low joint inclusion probabilities for nearby units, thus forcing the samples to be well dispersed. Combining the notion of balancing with that of spreading, Grafström and Tillé  method, which enables the selection of samples that are balanced on several auxiliary variables and at the same time are also well spread for some variables, which can be geographical coordinates. In this sense, the LC method can be considered an extension of the LP method. Moreover, Grafström and Lundström  on each of the M:Consider the following generalized linear Model nd Tillé  proposeda et al. , we haveJoining together the previous results, we obtainHorvitz–hompson estimator under the adopted model as follows:The first component of the anticipated variance, pression  and can pression  considerpression  and can t in Eq. , \documepression . FinallyTo achieve efficiency, we adopt a sampling algorithm for the first-stage sampling which ensures that joint inclusion probabilities undström , if the C of Eq.  by geogrD in Eq.  tends toIn synthesis, taking as fixed the first-order inclusion probabilities Under the constraint that the first-stage sample size is fixed optimal solution when spreading and balancing the sampling in both stages.Therefore, we see that the PPS solution, given by Above, we implicitly hypothesized that balancing and scattering of the sample in each of the two stages may nullify (more or less) the terms D in Eq. .However, in designing practically feasible sampling strategies, we cannot completely neglect any of these terms. All feasible designs leave a residual that we cannot eliminate. We can better study the residuals by reformulating the AV as follows:Let us first consider spreading. Having the clusters' spatial coordinates, we can quickly spread the first-stage sample on the geographical variables. For all practical purposes, we can assume that the joint probabilities obtained through the LP algorithm are a good approximation of the optimal joint inclusion probabilities that minimize the term Because the distances between units in the same cluster are tiny, the effectiveness of the second stage derived from local pivotal sampling may be poor. Indeed, the correlation values Let us now consider the balancing. First, let us note that it is not conceivable to balance directly on the We may express the component In the context of the pandemic, possible choices of The first equation in  assumes ation in  identifimentclasspt{minimaFinally, we note that balancing the sample requires the availability of a population register with balancing variables To summarize the results presented in this section, the best strategy to follow in practical cases is to balance the first-stage sampling on the This strategy approaches the theoretical optimum In addition, the difference between above design's efficiency and the maximum efficiency . Contagion is simulated to occur during the meeting of individuals and during their movements in the geographical space with a probabilistic mechanism. Epidemic curves are then simulated with the mobility and social interaction mechanism and divided into two phases. In the first 4 weeks Phase 1), the interaction corresponds to a situation of normality, while in the following 6 weeks (Phase 2), we simulated a state of lockdown. The main results are reported in Fig. , the intTo measure the impact of the spatial correlation of the susceptible population and mobility, for each day of the pandemic, we calculated the Moran index Moran  for bothFor comparison, our experiment considers six possible first-stage alternative sampling designs as follows: (1) fixed-size probability proportional to size (FPPS), (2) local pivotal (LP) method, (3) local cube method (LC) based on verified infected (LCBV) in which the balancing variables use the first equation in (14) to specify the Given the way we created the pandemic simulation, the variables influencing the probability of becoming infected at the level of a single unit of the design LCBI are the following: number of people, total distance and number of travels, total number of contacts and rate of the known infected of the cluster. The designs FPPS and LCBI represent the lower and upper bounds of efficiency, respectively. The LCBI design is not feasible in practice since we would have to record all relevant auxiliary information at the unit level that influenced the spread of the infection in the sampling frame. Using the artificial population generated as described in Sect. To add further insights, in Table The LCBV method performs best with respect to the other sampling strategies because of the assumption of homogeneous screening. In the previous simulation, we assumed that all the infected people have the same probability of being discovered. Although sometimes empirically grounded  appears to be more robust and it performs better than the one balanced only for the number of known infected people neglecting space. Considering that in practical instances the relationship between known and unknown infected cannot be known a priori, the LCBG may be a good choice. Indeed, it approaches the optimal accuracy provided by the LCBVG sampling.To complete our analysisE in Eq.   The value of  Formula , is relaTo summarize, the proposed strategy based on spatially balanced sampling in the first stage and simple random sampling in the second stage achieves a very high level of efficiency since it cancels out more than 70% of the positive components of the AV. The second-stage sampling could achieve only a 20% additional efficiency, but this gain may jeopardize the survey’s feasibility.The aim of this paper was to improve the current practice in epidemic data collection by introducing sampling designs that exploit the intrinsic peculiarity of data of being positively spatially correlated. In this context, we studied the feasibility and efficiency of two-stage sampling designs to estimate critical parameters of COVID-19 infection. The National Statistical Institutes could implement them rather quickly to provide timely information on the development of the pandemic. We propose to adopt spatially balanced sampling in the first stage and simple random selection in the second stage. This strategy is efficient and feasible. Since the phenomenon of infection is positively correlated, spatial sampling allows gaining efficiency by spreading the first-stage sample over space. The balancing strategy leverages aggregated data on the number of verified infected people often available at the primary unit stage level in many countries. Simple random sampling in the second stage does not require information at the unit level. Since the essential auxiliary variables are only represented at the aggregate level, the strategy we provide is also significant from the perspective of its viability in terms of privacy compliance.Thanks to a simulation study, the theoretical optimality properties of the estimators were confirmed, and the advantages derived from the introduction of the spatial dimension appear to be highly relevant.The results obtained in this paper encourage us to extend our research in several directions. Indeed, some developments represent a natural extension of the present proposal. The simulation could be extended by adding information such as age, sex and professional condition that are useful to balance the sample, thus further improving the efficiency of the estimators. Different forms of map structure, population density and mobility schemes could also be introduced to represent different types of urban contexts or regional settlements to tailor the design to different real cases. Other possible developments may concern the adaptation of the proposed method for the selection of sample units to which diagnostic tests seeking to trace the diffusion of the virus can be administered. One good example is the tracing of the variants of COVID-19 observed in the 2021 waves, with a specific focus on their geographical spread.


T2 and Q. In order to investigate the proper upper control limits, AKDE was utilised to estimate the underlying probability density functions of T2 and Q by taking the nonlinearity of the hydraulic system variables into consideration. The advantages of the proposed approach for incipient fault detection are illustrated via a marine power plant lubrication system.Incipient fault detection in a hydraulic system is a challenge in the condition monitoring community. Existing research mainly monitors abnormal working conditions in hydraulic systems by separately detecting the key working parameter, which often causes a high miss warning rate for incipient faults due to the oversight of parameter dependence. A principal component analysis provides an effective method for incipient fault detection by taking the correlation of multiple parameters into consideration, but this technique assumes the systems are Gaussian-distributed, making it invalid for a dynamic non-Gaussian system. In this paper, we combine a canonical variable analysis (CVA) and adaptive kernel density estimation (AKDE) for the early fault detection of nonlinear dynamic hydraulic systems. The collected hydraulic system data set was used to construct the typical variable space, and the state space and residual space are divided to represent the characteristics of different correlations between the two variables, which are quantitatively described using Hotelling’s  The influence of hydraulic systems, ranging from oil production platforms and truck-mounted drilling rigs to powered supports in coal mining, on various engineering equipment in modern society has been increasing . In pracOne can distinguish between three types of hydraulic system faults according to time evolution: abrupt, intermittent, and incipient ,4. CurreRisk-based fault detection and diagnosis have successfully developed in recent years, largely improving the working safety of hydraulic systems. Among all process fault detection methodologies, multivariate statistical process monitoring (MSPM) is an advanced data-driven condition monitoring approach . DiffereCanonical variate analysis (CVA) is a state-space-based system and dynamic characteristic analysis approach . The staIn this paper, a novel hydraulic systems incipient fault detection approach is proposed using CVA and a new extension of KDE, i.e., Adaptive KDE (AKDE), by overcoming the disadvantages aforementioned. The state space and residual space of hydraulic systems are firstly constructed using CVA by modelling the time-varying characteristics of system variables. Two multivariate statistics, The rest of this paper is organised as follows: The condition monitoring of an engineering system is usually achieved via separately monitoring the key working parameters or features which define the performance of the system to some extent. This technique has limited ability to detect small performance shifts, which are the basic characteristics of incipient faults. The difficulties of this technique for detecting incipient faults are that the system parameters/features are not independent from each other, and any one of them is not adequate to define the work performance of a system. Therefore, the fault detection of a system has multivariate properties, which means the performance of a system should be defined by the correct simultaneous values of all observed parameters.The principle and advantages with using MSPM techniques detecting incipient faults can be illustrated via This example clearly shows the difficulties of independent univariate-based approach for incipient fault detection and also shows the advantages of the MSPM approach on this problem. In the following parts, we show the CVA model for hydraulic systems incipient fault detection.Canonical variable analysis establishes a state-space model of a dynamic system by finding the maximum correlation between past and future variables in the normal condition. Let The input variables of a system are constant at a stable normal operating point. Therefore, the nonlinear dynamic system can be described as a stochastic state-space model, and Equation (1) is then converted into a more computable form asSuppose As for a sample data set with The CVA constructs the state space of a system by finding the linear combinations of past and future variables with maximum correlation. Let Let The Hotelling’s A hydraulic system modelled in Equations (1) and (2) can be monitored according to the For a hydraulic system described in Equation (2), if we ignore the system nonlinearity and only take system disturbance The UCL of The upper control limits in Equations (20) and (21) are derived under the assumptions that the measurements are Gaussian, and the nonlinearity of the hydraulic system behaviour is not directly accounted for. Hence, this assumption is valid for a hydraulic system in practice and inevitably leads to misdiagnosis. This section presents a novel AKDE-based upper control limits assignation approach by estimating the actual probability density functions of Since the The bandwidth A pilot PDF estimation The initial bandwidth The procedure above shows the estimation of The This section takes the hydraulic lubrication system of a large marine power plant as an example to illustrate the proposed approach, given that the working condition of the lubrication system is critical to a large marine power plant, and the working pressures and oil temperatures are key parameters for lubrication system control.The hydraulic lubrication system continuously provides clean, cool lubrication and hydraulic fluid to the marine power system. From the oil pump, the oil enters the cooler and filter successively where the oil temperature is adjusted to a desired value and the impurities are removed from the lubricating oil. The oil cooler is connected with a heat control valve in parallel, and the valve opens to make the oil bypass the cooler when the temperature is too low. A bypass valve is configured in the pipeline to guarantee the oil supply. When the filter is blocked, the differential pressure at both ends of the filter will exert sufficient force against the compression spring to open the valve, and the oil would pass through the valve for oil supply in an emergency. Oil then enters into the power plant with a certain pressure and temperature through the main oil gallery. A pressure-regulating valve is installed in the main oil gallery to control the oil pressure for the desired range. The oil out of the plant flows back to the sump for the next cycle.Three common gradual faults of a marine power plant hydraulic lubrication system, i.e., pump failure  signals . The marThe working condition of the hydraulic lubrication system is monitored using Pauta criterion, PLS, a PCA-based multivariate statistical approach and the proposed CVA with an AKDE approach, respectively. The Pauta criterion is the most widely used univariate statistics-based fault detection method in practice, while PLS and PCA are the two most classical MSPM condition monitoring approaches and have been successfully used in processing monitoring. The comparisons with the two approaches aim to reveal the advantages of MSPM for incipient fault detection and to illustrate the improvements regarding fault detection performance by taking system time-varying characteristics into consideration using the proposed CVA with AKDE. The incipient fault detection technical procedure using CVA with AKDE is shown in This section firstly takes the pump failure The FDRs of all nine fault categories using the Pauta criterion, PLS and PCA-based multivariate statistical approaches and CVA with AKDE are presented in In order to compare the computation speed and efficiency more intuitively, we use MATLAB to measure the time consumption of PLS, PCA and the proposed method. The computer used is configurated with 32 GB RAM and i5-12500, 3.00 GHz CPU. All the other processes on the computer are closed while testing. For each test, the time consumption is recorded after running the code several times to make the MATLAB run stably. In this paper, a novel nonlinear dynamic hydraulic system incipient fault detection method is proposed by combining CVA with AKDE to overcome the disadvantages of existing approaches on time-independent and Gaussian assumption. The approach is illustrated via a hydraulic lubrication system of a marine power plant. Three common gradual faults are introduced to the system at typical working loads and speeds. The monitoring performances of the proposed CVA with AKDE are compared with the Pauta criterion, PLS and PCA-based MSPM approaches. Results show that the incipient faults that are hard to be detected by the commonly used Pauta criterion can be effectively observed via the MSPM approach. The FDRs of the hydraulic system can be further increased using the CVA with AKDE technique by modelling time-varying characteristics of system states and by directly estimating the underlying PDFs of fault detection metrics,


Surgical treatment of Budd-Chiari syndrome (BCS) includes endovenectomy followed by angioplasty of the inferior vena cava (IVC). Herein, we report a case of surgery using an open-chest approach in a patient with BCS. We modified the technique reported by Kuniyoshi et al.A 45-year-old male, was diagnosed with BCS and referred to our hospital. We used an open-chest approach to remove stenosis in the IVC and angioplasty with a bovine pericardial patch. Endovenectomy and angioplasty were performed by clamping the stenosis above and below it with Pringle's clamping under extracorporeal circulation. The patient is currently undergoing outpatient follow-up 14 months after the surgery, and his liver function and blood test results were normal, with no symptoms.The main advantage of this technique is that the liver is not mobilized from the diaphragm, which allows for the preservation of collateral blood flow between the diaphragm and liver, reducing the amount of intraoperative blood loss and damage to the liver parenchyma due to intraoperative congestion. In addition, no mobilization of the liver from the diaphragm will prevent future surgical difficulties due to adhesions during total hepatectomy when liver transplantation becomes necessary.The techniques described in this article include procedures that cardiovascular surgeons usually perform such as thoracotomy, pericardiotomy, and extracorporeal circulation. Collaborative work by hepatobiliary surgeons and cardiovascular surgeons can achieve successful outcomes with this procedure in patients with BCS. •Surgical treatment for Budd-Chiari syndrome includes endovenectomy followed by angioplasty.•Kuniyoshi, et al. reported approach from the thorax to the dorsal side of IVC.•We modified the surgery reported by Kuniyoshi, et al. with Pringle maneuver.•Hepatobiliary surgeons should be familiar with these techniques. In adFurthermore, if liver transplantation is necessary in the future, this approach can help reduce the difficulty of liver transplantation, including bleeding during the dissection phase of total hepatectomy associated with adhesion between the liver and the diaphragm. Given the above, the method reported by Kuniyoshi et al. is considered useful for helping hepatobiliary surgeons who perform BCS for the possibility of liver transplantation .Herein, we report angioplasty of the IVC with a bovine pericardial patch via the open chest dorsal approach for BCS.2Ethical approval for this case report was provided by the Institutional Review Board of Nagasaki University Hospital (No. 19102143) on October 22, 2019.This work was reported in line with SCARE criteria .A 45-year-old male, was diagnosed with BCS and referred to our hospital. Contrast-enhanced computed tomography (CT) showed stenosis of the IVC just above the confluence of the hepatic veins , and angThe patient's chief complaint was an impaired quality of life due to marked edema in the lower body. The possibility of stenting the stenotic lesion of the IVC by interventional radiology was considered, but a direct approach to the IVC and reopening of the occluded IVC and hepatic veins under cardiopulmonary bypass was ultimately decided as the approach to resolve not only the stenosis of the IVC but also the obstruction of the middle and left hepatic veins. The patient underwent a direct approach to the IVC and reopening of the occluded IVC and hepatic veins under cardiopulmonary bypass to treat the IVC stenosis and hepatic vein occlusion. We planned an open-chest approach to remove the stenosis in the IVC and reopen the occluded hepatic veins and angioplasty with a bovine pericardial patch by collaborative surgery with a cardiovascular surgeon by clamping the inferior vena cava above and below the stenosis with Pringle's clamping under extracorporeal circulation.3The patient was placed in the left semi-prone position. The right femoral artery and vein were taped in preparation for the extracorporeal circulation. An incision was made continuously from the sixth intercostal space above the umbilicus, with the right lateral border at the axillary line and the left lateral border at the midline. During laparotomy, the umbilical ligament was preserved as much as possible to preserve the collateral blood vessels.The diaphragm was incised caudally on the right side of the liver under one-lung ventilation. The collateral vessels between the diaphragm and the liver were preserved. The hepatoduodenal ligament was encircled in preparation for the subsequent Pringle procedure A. TapingTo rotate the liver to the left, we proceeded to partially incise the diaphragm on the cranial side of the right lobe of the liver and confirmed the location of the IVC B. DuringAfter encircling and securing the right phrenic nerve, we encircled the IVC in the pericardial sac in preparation for the subsequent incision of the IVC, removal of the membranous part, and patch plasty. The dorsal surface of the IVC was gradually revealed by incising the diaphragm on the dorsal surface with an energy device  After palpation and transesophageal ultrasound (US) revealed an area of stenosis, we proceeded with the diaphragmatic incision from the cranial side towards the caudal side at the 6 o'clock point on the IVC so that sufficient working space could be secured. As further diaphragmatic incision might cause damage to the collateral vessels, the incision was limited to the same area. The stenosis was again checked, it was solidly palpated, and the same area was confirmed by transesophageal US. We decided to incise the IVC as planned, and endovenectomy was performed after approaching the stenotic site C. SubseqAfter setting the preparation for extracorporeal circulation, the infrahepatic and intrapericardial IVC were clamped, and an incision was made in the IVC using the Pringle maneuver. Observation of the inside of the IVC revealed a white, organizing membranous structure that was considered the cause of the stenosis. While removing the membrane-like structure, the suction tube was inserted without resistance to the caudal side of the IVC. Further removal of the remaining membranous structures allowed the insertion of the suction tube without resistance into the left hepatic vein. At this point, we determined that the stenosis caused by the membranous structures had been removed. The incision was 4 cm in length and a bovine pericardial patch . IVC patch plasty was performed with continuous 4-0 monofilament non-absorbable sutures. When IVC angioplasty was completed, the clamp was released. From IVC incision to the patch-forming procedure, the total ischemic time of the liver using the Pringle method was 35 min. The pericardium was closed using continuous suturing. A 24-Fr thoracic tube was inserted into the thoracic cavity through the eighth intercostal space. Blood pressure and other vital signs were stable during the surgical procedures. The operation time was 6 h 53 min and the estimated blood loss was 641 g.The patient was extubated on the first postoperative day and was discharged from the intensive care unit on the second day. Postoperatively, the patient developed cardiac tamponade due to bleeding in the pericardial sac and underwent pericardial drainage; however, his condition stabilized thereafter, and he was discharged home. Postoperative contrast-enhanced CT on postoperative day 9 showed a widely patent IVC and orifice of the hepatic veins, with homogenous enhancement of the liver parenchyma . Further4The procedure described herein for BCS, in which an open thoracic approach was performed at the dorsal side of the IVC from the thoracic cavity, was performed safely. With this procedure, as in the case presented here, the imaging findings and symptoms improved rapidly after surgery.The original technique of this procedure reported by the University of the Ryukyus group approaches the lesion directly via a right thoracoabdominal incision and is appropriate for repairing lesions of both the IVC and hepatic veins simultaneously . InafukuThe main advantage of this technique is the approach to the IVC without mobilization of the liver, which allows for the preservation of collateral blood flow between the diaphragm and liver, thereby reducing the amount of intraoperative blood loss and reducing damage to the liver parenchyma due to intraoperative congestion.In addition, no mobilization of the liver from the diaphragm will prevent future surgical difficulties due to adhesions during total hepatectomy when liver transplantation becomes necessary. In particular, in living donor liver transplantation, the recipient's native IVC may have to be preserved ; if the A previous report described excellent results with IVC incision, endovenectomy, and subsequent angioplasty, without interrupting blood flow. However, in the method reported in this study, we performed the Pringle procedure. TVE was achieved during liver surgery by clamping the suprahepatic and infrahepatic IVC and performing the Pringle procedure, total vascular occlusion (TVE) during liver surgery was achieved. Favorable outcomes have been reported in patients undergoing hepatic resection with TVE have been reported ,9. UsingIn the present case, we used a bovine pericardial patch for angioplasty of the IVC, and good results with this technique have been reported . Althoug5Although the techniques described in this article include procedures that cardiovascular surgeons usually perform, such as thoracotomy, pericardiotomy, and extracorporeal circulation, hepatobiliary surgeons also familiarize themselves with these techniques in preparation for handling the liver in BCS and for future transplantation. This method is also expected to be useful as an approach to IVC of the liver. Collaborative work by hepatobiliary surgeons and cardiovascular surgeons can achieve successful outcomes with this procedure in patients with BCS.Radical open endvenectomy was followed by angioplasty of the inferior vena cava with a bovine pericardial patch using the open chest dorsal approach.Supporting video 1The following is the supplementary data related to this article.Written informed consent was obtained from the patient for publication and for any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal upon request.This study was approved by the institutional review board, and informed consent was obtained from the patient. Ethical approval for this case report was provided by the Institutional Review Board of Nagasaki University Hospital (No. 19102143) on October 22, 2019.This case report received no specific grants from any funding agency in the public, commercial, or not-for-profit sectors.(I)Conception and design: Soyama, Eguchi.(II)Administrative support: Ogawa, Hara, Adachi.(III)Provision of study materials or patients: Soyama, Ogawa, Hara.(IV)Collection and assembly of data: Soyama, Ogawa, Hara.(V)Data analysis and interpretation: Soyama, Ogawa, Hara, Adachi, Miura, Eguchi.(VI)Manuscript writing: Soyama, Eguchi.(VII)Final approval of manuscript: All of the authors.The guarantor is Akihiko Soyama.This report is not applicable to this topic.The authors declare that they have no conflicts of interests.


In this paper, we provide a systematic review of atomic force microscopy (AFM), a fast-developing technique that embraces scanners, controllers, and cantilevers. The main objectives of this review are to analyze the available technical solutions of AFM, including the limitations and problems. The main questions the review addresses are the problems of working in contact, noncontact, and tapping AFM modes. We do not include applications of AFM but rather the design of different parts and operation modes. Since the main part of AFM is the cantilever, we focused on its operation and design. Information from scientific articles published over the last 5 years is provided. Many articles in this period disclose minor amendments in the mechanical system but suggest innovative AFM control and imaging algorithms. Some of them are based on artificial intelligence. During operation, control of cantilever dynamic characteristics can be achieved by magnetic field, electrostatic, or aerodynamic forces. With the rapid increase in the popularity of micro- and nanotechnologies and the growing scope of their practical application, there is an inevitable need to develop and improve the technologies and equipment required to research micro- or nanostructures. The cantilever’s design and suitability for different environments and working modes are revealed.The first commercial model of AFM was built in 1989 and quickly became one of the most essential tools for the development of nanotechnology ,3,4,5,6.This review focuses on widely used AFM state-of-the-art designs, reviewing cost-effective scanning speed and resolution improvement techniques and methods. From the vast amount of available information, we included in our review of papers published in the last decade that provide software or hardware improvement solutions. Priority was given to the most recent innovations with a comprehensive explanation of existing limitations, justified technical solutions, and validated modeling or experimental research results. Our review contains a detailed scientific analysis of state-of-the-art data in the field, describes the most popular AFM scanner and cantilever designs and operating modes, and comes back to the reader with a systematic approach to the cost-effective performance improvement of existing AFMs.F is the tip–sample interaction force, k is the equivalent spring constant of the cantilever, and dz is the deflection of the cantilever. The sample’s surface topography parameters are obtained from the error signal, defined by the difference between the setpoint deflection and the actual value of dz. To determine the properties of sample materials, such as adhesion, friction, or viscosity, more cantilever deformation modes can be measured, for example, twist or deviation  in the horizontal plane [AFM makes use of the class of scanning probe microscopes in which the sensor contains the one-side held cantilevered probe with a nanometer-sized tip attached at the free end. AFM’s operation principle is based on keeping a constant interaction force between the tip and the sample surface when the probe moves along the sample surface . The tipal plane .Typically, AFM consists of a few functional blocks: a positioning stage, a cantilever, a scanner, a controller, data processing, and visualization algorithms . The posThe complex sensor contains a cantilever, an optical system, and a scanner. Cantilever properties  depend on the design and material properties. Dynamic cantilever characteristics directly impact measurement result reliability since these characteristics limit the maximum possible scanning velocity and resolution . Cantilez-axis feedback to the controller. The z-axis deflection error signal and the tip coordinates are also transferred to the data acquisition and processing software to produce a three-dimensional image of the sample surface.The cantilever deflection is usually measured by an optical system consisting of a laser source and position-sensitive photodiode matrix . The lasCantilever deflection can also be measured by nonoptical methods based on capacitive, piezoelectric, or piezoresistive phenomena ,14,15,16Before imaging, a few scanning parameters must be chosen: the size of the field of view, the scanning mode and speed, and the number of lines and points in each line. All these parameters will affect the overall image acquisition duration and future image resolution . The mosOptimization of the scanning parameters is one of the paths for increased AFM performance. Usually, the optimization strategy is subject to AFM operator experience and skills, and the optimization algorithm is based on the database  or a matDepending on the interaction between the probe and the sample surface, three main AFM operating modes can be distinguished: contact mode, noncontact mode, and dynamic contact (tapping) mode ,24. The The contact mode of AFM is based on scanning the surface in repulsive force mode by keeping a constant 1–2 Å distance from the sample surface. In this scanning mode, cantilever stiffness is essential since it directly impacts the cantilever’s deflection amplitude. Therefore, cantilevers of lower stiffness enable the imaging of surfaces with smaller feature sizes since the higher deflection of softer cantilevers produces a more significant error signal. On the contrary, if the cantilever is stiff and the sample surface features are small, the error signal can be too small to be sensed. The advantage of the contact mode is that a thin layer of water, which is always present on the surfaces of solid samples at standard conditions, has a minor influence on the measurement results. Therefore, due to the strong surface forces, the probe is attracted to the sample surface and “pierces” the water layer . The conThe speed limit is the main disadvantage of the contact mode. The low resonant frequency of soft cantilevers is the cause. During the scanning process, the sample surface structure causes kinematically excited oscillations of the cantilever. The frequency of these oscillations depends on the scanning speed. When the cantilever’s excitation frequency approaches its resonant frequency, the contact between the probe and the sample becomes unstable, making scanning results inaccurate . AnotherWhen the cantilever tip is near the surface of interest, an attractive Van der Waals force occurs between the tip and the surface. Scanning at the distance of attractive force is called noncontact mode, and it is mainly used for the analysis of soft  materials. In this mode, a special piezoelectric resonator mounted on the AFM cantilever fixture place  kinematiz-axis position of the AFM scanner is used to maintain the constant oscillation amplitude of the cantilever. The image is obtained by mapping the z-axis feedback signal, which corresponds to the variation of the tip–sample interaction force [The tapping mode lies between the contact and noncontact modes and has features of both. In this mode, the cantilever is kinematically excited by the piezoelectric resonator, similarly to in noncontact mode . The onlon force . The maiz-axis position feedback [It is essential to mention other scanning modes when AFM operates in the intermediate regime between repulsive and attractive forces: peak force tapping and phase imaging. The first enables precise control of probe–sample interaction at very low interaction forces . Typicalfeedback . This scfeedback . Furtherfeedback . The firOne of the prospective modes of AFM, which allows increasing imaging resolution, is multifrequency AFM, in which the cantilever is simultaneously excited/observed at two or more separate frequencies ,38,39. Ix-axis direction, the number of scan lines, the spatial frequency of the sample surface, and the maximum possible phase delay in tracing the sample surface [While scanner properties remain constant, imaging speed can be optimized by choosing the proper scan range in the  surface . AFM perAll the categories mentioned above contain several subcategories. The development of cantilevers focuses on the improvement of the following parameters: I—an increase in the resonant frequency of the cantilevers; II—optimization of the probe geometry; III—the application of various surface coatings for better reflectance or the production of specialized cantilevers whose deflection can be measured using the nonoptical method; IV—cantilever arrays suitable for multiprobe scanning; V—new materials for cantilever manufacturing.The research focused on the in situ control, modification, and adjustment of cantilever characteristics is based on the hypothesis that instead of selecting and changing cantilevers for each case, it is possible to modify the dynamic characteristics of the cantilevers in situ, thus extending their field of application. This approach requires the application of external controllable force on a probe surface. This can be performed using magnetic, electrostatic, or aerodynamic force on the cantilever surface .The AFM scanner improvements cover two general areas: software and hardware. Software improvement focuses on scanning trajectory optimization, the development of advanced control, and data processing methods. Hardware modernization concentrates on the enhancement of scanners and measurement systems.In the next sub-sections, we will focus on the cantilever properties, in situ cantilever characteristic adjustments, and AFM software improvements as mostly cost-effective and highly available methods, skipping the review of radical hardware engineering approaches, such as multiprobe designs ,42 and cThe resonant frequency and bandwidth are the parameters that determine the dynamic properties of the cantilever. A wider bandwidth means more damped behavior, and a narrow bandwidth means more oscillating behavior. The idea of the AFM sensor as a dynamically sensitive mechanical system remained unchanged for several decades until the concept of cantilever-less AFM sensors came about . Still, 3N4) using photolithography, etching, and other microfabrication technologies [Modern cantilevers are typically fabricated from monocrystalline silicon (Si) or silicon nitride  to operate above the resonance frequency.The classical vibration theory  suggestsNumerous papers describe optimizing the cantilever’s resonant frequency and stiffness by changing its geometry ,53. The Experiments with differently worn tips were performed in  Figure . The autTypical cantilevers are 85–500 µm long and have resonant frequencies less than 500 kHz . The papUltrathin 60 nm) silicon cantilevers with force constants in the range of µN/m and resonant frequencies in the vacuum of 1.7 kHz were made for work in the air  nm silic,61. The Further improvements and optimizations of AFM cantilevers and their tip geometries will contribute to the availability of adequate photolithography and thin-film deposition/etching technologies.2 and depositing a layer of material which will form the final cantilever on the sacrificial one. The sacrificial cantilever will be etched away. A compound cantilever fabricated from two fused silicon oxide wafers was made with a separate bending and vibrating part [We provided a method suitable for making 2–10 µm length cantilevers . This meing part . The vibResearch on the relationship between geometric parameters and the stiffness of the triangular cantilever in the literal, standard, and longitudinal directions was performed ,64. The Several scientists have conducted similar studies dedicated to creating cantilevers with specific resonant frequencies by changing the geometry of cantilevers. The paper  presentsThe impact of tip conicality and tip apex radius on AFM accuracy was investigated in a couple of works ,70. The In , a detaiThe research efforts directed toward fabricating cantilevers with a smaller tip radius are constantly growing. A smaller tip radius is necessary to increase AFM scanning resolution and accuracy. It is also essential to note that imaging error, caused by the tip radius size, increases during the process due to mechanical wearing, especially during scanning of hard surfaces in the contact mode ,74. The Using copper oxide nanowires leads to the development of operable sensors, but their accuracy is slightly lower than that of the standard AFM sensors. The decrease in accuracy appeared to be due to the nanowire deformation during the scanning process . It is aResearch on the physical parameters of cantilevers, including the shaping of the cantilever tip, targeted for improved AFM performance, indicates some pathways for possible advances beyond the state of the art, but only for narrowly specified applications . The maiAFM cantilevers made of silicon or silicon nitride have approached the limits of their speed/resolution capability. The production of more miniature cantilevers with sharper tips or higher resonant frequencies is challenging due to the limitations of traditional technologies . AlternaSilicon and silicon nitride have relatively low reflectivity. Therefore, cantilevers are coated with a gold or aluminum layer for proper optical detection to increase reflectivity. This way, an unwanted temperature-sensitive bimaterial strip is created, which will unpredictably deform due to the temperature change and cause the drift of the readings. This effect becomes especially significant for miniature cantilevers since the metal layer’s thickness is comparable to the cantilever’s. If cantilevers were made only from metal, it would be challenging to control residual stress in thin metal films as it would cause most metal cantilevers to bend . Adding Piezoelectric coatings can be used to adjust the cantilever’s stiffness or damping parameters, increasing the scan rate and imaging accuracy in tapping mode AFM . It was Piezoelectric cantilever coatings can also eliminate optical readout from the AFM, thus simplifying it. One of the most popular piezoelectric materials is zinc oxide (ZnO), which can be deposited in a thin film. Moreover, a piezoelectric coating allows the simultaneous use of a cantilever as a high-resolution nanoactuator. It has at least a two times higher sensitivity potential than the optical readout systems. Researchers showed that this method enables multiprobe imaging with several cantilevers working in parallel . AnotherRecent cantilever setups with piezoelectric actuators are sensitive to ambience disturbances and have high electrical isolation requirements since a comparatively high voltage is used. An isolated AFM cantilever with a piezoelectric film was designed for operating in a noncontact mode in a liquid environment . This kiThe main disadvantages of the AFM cantilevers with the piezoelectric films are as follows: deposition of piezoelectric thin films increases the overall thickness of the cantilever and introduces intrinsic stress . There hIn 1994, Florin  proposedAnother approach is to complement the AFM technique by measuring the electrostatic force during the short-range tip–sample interaction . This alDuring AFM operation, the magnetic field can be used for cantilever actuation. The magnetic field enables simultaneous micromachining and surface characterization processes . The autRecently, in situ cantilever dynamic adjustment was proposed by applying aerodynamic force on the cantilever’s upper surface ,96,97. TAFM cantilever actuation in fluid media can be performed by micro-electromechanical system (MEMS) acoustic transducers operated at very high frequencies of 100-300 MHz . Not onlEven though the in situ cantilever dynamic adjustment method seems promising and gives outstanding results, it is seldom used in practical applications since it requires modifications which complex and expensive commercial AFMs can hardly tolerate. The custom modification of their design or components usually voids the warranty and makes proper commercial equipment maintenance difficult. Overall, these methods lead to increased scanning speed and improved resolution, which generally would be limited by the properties of cantilevers.z-axis and x–y axe drives [The dynamic characteristics of AFM cantilevers are the primary factors limiting the imaging speed of commercial AFMs. Nevertheless, imaging speed is also heavily determined by the scanner design, control, and data processing algorithms. There are several trends for scanner design improvements , from the drives . Increasz-axis [y-axis and fast piezoelectric x-axis drive allowed a scan of a 170 × 170 µm area in one second with an average tip velocity of 13–28 cm/s (or peak tip–sample rates of 20–44 cm/s). An AFM scanner with rotational scanning eliminates the delays of reciprocating movement and achieves a higher scanning speed with a larger field of view [High-speed AFM with a parallel kinematic piezoelectric actuator demonstrated significantly higher resonance frequencies: 5.6 kHz for the x–y axes and 29 kHz for the z-axis . A fieldz-axis . The conz-axis . A comme of view . A lineaSometimes, AFM performance can be improved by carefully optimizing all scanner components . The resMany articles disclose minor amendments in the mechanical system but suggest new or improved AFM control and imaging algorithms ,107,108.A systematic summary of the research focused on improvements in scanner design and control algorithms is provided in According to the information gathered in the present review, we produced a graphical algorithm of the parametrization of AFM by sample properties and cantilever parameters optimized for improved performance, as illustrated in The selection of the proper AFM scanning mode is a matter of trial and error and not a straightforward decision. For example, it is widely known that the contact mode gives the highest accuracy and allows the fastest scanning. However, there is still uncertainty related to the surface properties of the sample. This mode is unsuitable for soft materials, and there are no well-established methods to determine whether a material is too soft for the contact mode before the actual contact mode scan is performed. Furthermore, it depends on sample stiffness and homogeneity . Also, the possibility of damaging or unintentionally modifying the sample surface depends on the scanning mode selection and the selection of the cantilever and scanning speed.Selection between noncontact and tapping modes is not trivial either; both methods have similar imaging capabilities but provide results with different accuracies and differ in the scanning process duration. Choosing a suitable cantilever for each scanning mode is one of the most critical factors for a successful AFM operation. It depends on sample characteristic requirements for expected results and usually relies on the availability of an adequate cantilever and user experience. The decision about cantilever selection can be facilitated using manufacturer recommendations or predictive mathematical models. However, even using a particular model, complex operations can require performing a test scan to evaluate the quality of the obtainable results.It is essential to note that selecting the proper scanning mode and optimal cantilever parameters remains complicated due to controversy over the technical capabilities of AFM, the quality of results, and scanning duration. It is always necessary to match the required scanning accuracy, image resolution, reliability of results, and scanning time. A higher speed minimizes the needed course of the operation, but at the same time it can reduce the accuracy and reliability of the results. Imaging resolution is also an equally important parameter. Typically, extended imaging time is required for better resolution; nevertheless, it can be balanced out by increasing the scanning speed within accuracy tolerance.While summarizing the reviewed imaging speed increase methods, we must note that the practical implementation of any method mainly depends on the nature and type of AFM design. Most improvements based on the optimization of cantilever design fit all commercial AFMs since they do not require any physical changes to the AFM structure. On the other hand, cantilevers with perfect functional parameters may lose their benefits due to the limitations of other AFM components. The improvement based on the change of AFM structure or in situ adjustment of the cantilever dynamics requires physical intervention. It is better suited for open AFM designs than for commercial ones. Software scanning pattern optimization and advanced imaging algorithms are the most applicable options for commercial AFMs since they do not require physical intervention into AFM hardware. Such improvements do not conflict with the warranty provided by the manufacturer and can be installed by the potential user according to their specific requirements. Moreover, AFM software improvements can be enhanced by modified cantilevers. It is likely that using such modifications and implementing machine learning algorithms for AFM control and data processing will enable multicriteria modernization of available and new AFMs, increase scanning speed and resolution, and even expand the functionality of AFMs.Many new methods and improvements were tested and demonstrated, resulting in a significant increase in scanning speed, up to 400 mm/s in particular cases. Regarding the future prospects of AFM technology, it can reach a more comprehensive implementation, especially in power electronics as a quality control method. This methodology fits the quality control of smart coatings and allows efficient imaging of biological and biochemical items. The faster AFM scanning process will increase technological parameters and foster breakthroughs in nanotechnology and related areas.AFM capabilities and functionality are developing quite dynamically, as is the popularity of the combination of AFM with other imaging techniques to perform simultaneous multimodal analysis of samples.


People with spastic cerebral palsy (CP) often experience a decline in gait function and flexion. The children’s posture and hip strategy, which leads to knee flexion, predisposes these children to increased contact area in the medial foot region. This study investigated the use of DAFO (dynamic ankle-foot orthosis) prescribed to patients with cerebral palsy (CP) to determine the plantar pressure distribution with orthosis use. Eight children with spastic CP (age 4–12 years) were classified as Gross Motor Function Classification System (GMFCS) levels I-II with a maximum spasticity level of 3 in their ankle muscles according to the Modified Ashworth Scale. We assessed the plantar distribution by using eight WalkinSense sensors in each trial and exported data from the proprietary software . The plantar pressure distribution was conducted under two conditions: only shoes and DAFO with shoes. The activation percentages for sensor number 1 under the 1st metatarsal and sensor number 4 under the lateral edge of the heel were significantly different under the DAFO condition. The 1-point sensor activation percentage significantly decreased, while the 4-point sensor activation percentage increased during DAFO walking. According to our study findings, there was an increase in pressure distribution in the lateral part of the foot during the stance phase in DAFO. DAFO improved the gait cycle and influenced the plantar foot pressure in children with mild cerebral palsy. Cerebral palsy (CP) is a complex pathology that affects cognition, language, sense, and gait patterns and severely impacts children . Gait deDiplegic gait is characterized as being a low-speed gait and is the main cause of muscle weakness and spasticity in the lower extremities . DynamicA dynamic ankle-foot orthosis (DAFO) with its supra-malleolar type and underfoot support structure has been increasingly used as an alternative to AFO for patients with CP . DAFO waDAFO, supra-malleolar orthosis, is a very thin flexible orthosis designed to support and stabilize the forefoot, foot arches, and subtalar joint. The foot sole structure especially created for the patient is designed to reduce abnormal muscle activity and to affect biomechanical changes. The orthosis allows for very small movements in the midfoot and forefoot, supporting foot function and providing more proprioceptive feedback for posture and balance improvement. Improvement in motor skills increases with the presence of movement stability and postural security .DAFO is designed as an orthosis that provides tone inhibition with a neutral alignment of the ankle and foot. A neutral forefoot in full contact with the orthosis and an outer structure that supports the subtalar joint is formed . DAFO wiAFOs used in children with CP have a positive effect on gait kinematics and kinetics by supporting motor skills and reducing energy expenditure in walking ,22,23,24With more dorsiflexion and knee flexion in the stance phase in the equinus pattern or dropped foot gait, DAFO is effective for children with a crouched gait pattern. Ankle dorsiflexion showed improvement in the swing and stance phase compared to barefoot, and it also did not differ in knee extension in stance, but hip extension was improved with DAFO ,31.Leunkeu et al. found that plantar pressure increases in the medial heel, decreases in the hallux and lateral heel during walking in hemiplegia, and increases the plantar loads on the first metatarsal, medial, and lateral midfoot in diplegia . In chilGait analysis evaluation parameters have been proven to be a valuable method for assessing the effect of orthosis in CP. However, non-studies have used plantar pressure distribution in the assessment of gait when wearing DAFO. The aims of this study were the effects of DAFO orthotic treatments on the plantar pressure distribution during gait in spastic patients with spastic CP.The evaluation was eight children with spastic diplegia CP (age 4–12 years); 2 were classified at Gross Motor Function Classification System (GMFCS) level I, and 6 were at GMFCS-level II; with a maximum spasticity level of 3 ankle muscles according to the Modified Ashworth Scale. The GMFCS objectively classifies a child’s current gross motor function in children with CP aged 1 to 12 years. The focus is on the child’s self-initiated movement with a particular emphasis on function in sitting and walking. The function is divided into five levels: children in Level I have the most independent motor function and children in Level V have the least . The patEthical approval was obtained for the study from the Medical Research Ethical Committee of the Ankara University Faculty of Medicine . All participants and their legal guardians were fully informed about the study and agreed to participate.The manufacturers of the orthoses determined the specifications of the orthoses provided to each participant (including the type of DAFO) based on a physical examination performed before molding, specifically the range of motion, muscle tone, and walking barefoot . As a reThe dynamic ankle-foot orthosis has been produced from 3/32 in (0.24 cm) polypropylene with the use of a contoured footplate, which enclosed the dorsum of the forefoot, and a plantar flexion block, with dorsiflexion being allowed through the flexibility of the plastic and the absence of a calf strap. There was no hinge, ankle, and covered the posterior part of the leg to about 5–7.5 cm above the malleoli. The fact that DAFO is made of thin and flexible material prevents the orthosis from breaking. Additionally, DAFO has a tailor-made dynamic foot orthosis (DFO) section. This section contains medial and lateral longitudinal arch reinforcements in the foot and supporting reinforcement for the transverse arch and calcaneus. Gripping support is created in the medial and lateral longitudinal arches from the front of the calcaneus, and the inclination of the calcaneus is prevented. Thus, full contact with the orthosis with the foot is ensured, helping distribute and carry the body weight in a balanced way. Full contact support also positively affects tone inhibition. In addition, with the elevation of the toes in the orthosis, the toes flexors are stretched, while the 2nd, 3rd, and 4th toes are elevated in the orthosis. The elevation of the 1th toe was less than the others. We performed this elevation while the casting procedure plaster reduced and shaped the toes’ elevation; we did not need extra addition soft material . Thus, wWith the velcro band surrounding the ankle at an angle of 45°, displacement of the calcaneus and the dorsal band of the foot within the beds of the metatarsals are prevented. With all these features, the flexible supra malleolar structure allows controlled movement of the subtalar joint and allows the foot to perform adduction, inversion, and abduction eversion movements within the orthosis, but this does not cause any adverse effects on mediolateral stabilization .The plantar pressure distribution under foot measurements was performed using 8 WalkinSense sensors in each trial and exported from the proprietary software  . The sysp < 0.05.Descriptive statistics were calculated for all the data. Statistical analyses were performed using the SPSS version 23 software. The nonparametric Wilcoxon test was used to compare only shoe measurements and DAFO with shoes, respectively, within each subject. Homogeneity could not be achieved within the group because it was studied with a small group. The statistical significance level was set at Eight children with mild cerebral palsy , who all had a dominant right leg, were recruited and performed the short distance stride repetitions while wearing and removing DAFO. All of them had received physical therapy at the rehabilitation center. The activation percentages for sensors 1 and 4 were significantly different under the DAFO conditions . The 1-pThis study aimed to evaluate the effect of DAFOs on foot plantar pressure distribution in patients with CP. DAFOs’ limited plantar flexion at push-off affects plantar pressure distribution underfoot. Our results showed an increase in the lateral foot pressure distribution at the stance phase in the DAFO. Orthotic devices are invented to support the ankle, correct deformities, and prevent further occurrences. With the DAFO arch support, the weight is evenly distributed throughout the foot, and the structure that stimulates the foot reflexes creates an effect closer to the normal function. Mediolateral stabilization provides grade dorsiflexion better and has been proven to reduce abnormal plantarflexion . Many stMany factors that play a role in the development of equinus deformity in patients with CP, including muscle imbalance, abnormal loading patterns, rotational gait deviations, and intrinsic anatomical features probably all play a role in the development of these deformities, and the plantar flexor lever arm is shortened in this foot deformity, which is often compensated by hip and knee flexion, and joint position affects gait control . In the Plantar pressure measurements clearly reflect changes in foot postural alignment and can be used to detect toe walking in children with CP . Femery The effect of DAFO on gait patterns has been shown in some studies, but we have not found any study on how it affects the pressure distribution under the foot. The use and application of gait analysis are extensive and can take time, and measurements taken with plantar pressure can be applied more practically in clinical applications and can be adapted to various areas. With the plantar pressure evaluation, it is possible to obtain information about abnormal gait, the severity of foot diseases and deformities, and rehabilitation status . JolantaThis study has several limitations. First, due to the small number of individuals with CP and the heterogeneity of the participants, the power of the statistical tests was generally low. Second, the long-term effects of an orthosis on functional activity also need to be investigated. Third, its effect on underfoot pressure distribution is comparable to other orthotic designs.In the current study, the findings of plantar pressure distribution indicated the potential use of DAFO orthosis to improve the gait cycle and influence foot motion in children with mild cerebral palsy.


Individuals spend time on online video-sharing platforms searching for videos. Video summarization helps search through many videos efficiently and quickly. In this paper, we propose an unsupervised video summarization method based on deep reinforcement learning with an interpolation method. To train the video summarization network efficiently, we used the graph-level features and designed a reinforcement learning-based video summarization framework with a temporal consistency reward function and other reward functions. Our temporal consistency reward function helped to select keyframes uniformly. We present a lightweight video summarization network with transformer and CNN networks to capture the global and local contexts to efficiently predict the keyframe-level importance score of the video in a short length. The output importance score of the network was interpolated to fit the video length. Using the predicted importance score, we calculated the reward based on the reward functions, which helped select interesting keyframes efficiently and uniformly. We evaluated the proposed method on two datasets, SumMe and TVSum. The experimental results illustrate that the proposed method showed a state-of-the-art performance compared to the latest unsupervised video summarization methods, which we demonstrate and analyze experimentally. Individuals spend time on online video-sharing platforms such as YouTube to search for videos. To reduce the search time, thumbnails or summary videos are used to efficiently and quickly grasp the video content . Over thThe reinforcement learning (RL) based unsupervised video summarization method proposed in  demonstrIn this paper, we propose a new reinforcement learning-based video summarization framework with the interpolation method, which is composed of a new network and a new reward function such as a temporal consistency reward. To increase the performance, we used graph-level features. We also present the transformer and convolutional neural network (CNN)-based video summarization network to accurately predict the importance scores, as shown in Video summarization methods are divided into supervised and unsupervised learning-based methods. Both methods use the video summarization dataset, which includes the frame-level or shot-level importance scores of the video annotated by several users ,7. The sIn , the memHowever, the issue with supervised learning-based methods is that it is very difficult to make a human-labeled video summarization dataset including videos of various categories. However, the unsupervised learning-based method does not need a human-labeled dataset. Many unsupervised learning-based methods have been proposed.In , the attDeep reinforcement learning combines a deep neural network with a reinforcement learning method . The polThe video summarization problem is formulated as a keyframe selection problem using the importance score predicted by the video summarization network. As illustrated in First, suppose the sequence length is oogleNet , which iIn recent years, graph neural networks (GNNs) have been extensively studied and it has shown state-of-the-art performance in various deep learning applications . In thisAs illustrated in terp-SUM , since tInterpolation is an estimation method that finds new data points based on the range of certain known data points. Specifically, piecewise linear interpolation connects the data points with the linear line and calculates intermediate data points on the line . We firsTo select the keyframes as a summary, the Bernoulli distribution (2) was used, which is a discrete probability distribution to convert the importance score To train the video summarization network efficiently, we adopted the diversity reward function and the representativeness reward function , and we The diversity reward function Let the indices of the selected keyframes be The representativeness reward function To create a superior summary of the video and increase performance, we applied the importance score The temporal consistency reward function To explain the temporal consistency reward in detail, as described in The quality of the generated summary was evaluated with the sum of the rewards. With the reward, the proposed video summarization network was trained as a parameterized policy was used . If the To calculate the objective function of UREX The baseline, an essential technique for the policy gradient to reduce the variance of the gradient estimate and improve computational efficiency, was applied. The baseline is calculated as the moving average of rewards experienced thus far. To reduce the variance efficiently, we calculated the baselines per input video. As illustrated in the equation below, baseline The regularization term posed in  was usedAfter all of the loss functions were computed, the final loss for video summarization Algorithm 1. Training Video Summarization Network2: Output: Proposed network’s parameters  method, which detects change points such as shot boundaries, is used . The shoOur proposed video summarization method was evaluated on two datasets: SumMe  and TVSuFor a fair comparison with other methods on two datasets, the evaluation method used in  to compuThe 5-fold cross-validation was used to find the performance of our method for a fair comparison. Our method was tested for five different random splits and the result of the average performance was taken. To create random splits, the videos were split into training and validation datasets. Moreover, the F-measure was computed using the validation dataset.The proposed video summarization network was developed using Pytorch 1.7.1 and consisted of a transformer encoder network and a Pointwise 1D Conv network. The transformer encoder network consisted of six transformer encoder layers with eight heads and 512 hidden units. Moreover, the Pointwise 1D Conv network was based on 15 kernel sizes and three stride sizes. The Adam optimizer was used to train the network with a learning rate of 0.00001 for 1000 epochs.As illustrated in We noted that the performance was decreased because of the lack of context information caused by the shorter importance score candidates as the kernel size and stride size increased. In addition, the performance decreased rapidly as the stride size increased. We observed that the performance degradation was caused by the missed context information between scenes due to the short length of the importance score candidates because the length of the importance score candidates is mainly influenced by the stride size. The result of the TVSum dataset showed better performance than the result of the SumMe dataset at a smaller kernel size. This is because the training efficiency of the video summarization network was low since the length of the importance score candidates rapidly shortened when the kernel size was large, and the video length was long like the videos in the TVSum dataset. In other words, the training efficiency of the video summarization network was decreased by the shortened importance score candidates. We chose the proposed method as the best-performing method showing the best F-measure (51.66) on the SumMe dataset and the second best F-measure (59.86) on the TVSum dataset. We chose the best-performing method because increasing the performance of a small number of videos such as the SumMe dataset is more complicated than the TVSum dataset.As illustrated in In this paper, we proposed an unsupervised video summarization method based on deep reinforcement learning with an interpolation method. We designed a lightweight video summarization network to predict the accurate importance score candidates of keyframes and we interpolated the importance score candidates with a piecewise linear interpolation method to generate a natural sequence of summary and to mitigate the high variance problem. To train the video summarization network by the reinforcement learning method efficiently, we used graph-level features and proposed a temporal consistency reward function to select keyframes uniformly and adopted the representativeness and diversity reward functions. The experimental results illustrate that the proposed method showed state-of-the-art performance compared to the latest unsupervised video summarization methods, which we demonstrated and analyzed experimentally. Moreover, the proposed method robustly summarized various types of videos in the two datasets. However, based on the experimental results, the proposed method showed a lower performance on long videos due to the high variance problem. Conversely, the proposed method showed the best performance on the videos that were shorter than about 300 keyframes. Therefore, the proposed method is very useful for the video summarization of short-form videos.