Background: This study aims to identify the preferred sources for acquiring knowledge about COVID-19 and to evaluate basic knowledge on critical scientific literature appraisal in students from medical schools located in Spanish speaking countries in Latin America. Methods: We designed an online survey of 15 closed-ended questions related to demographics, preferred resources for COVID-19 training, and items to assess critical appraisal skills. A snowball method was used for sampling. We conducted a descriptive analysis and Chi-squared tests to compare the proportion of correct identification of the concept of a preprint and a predatory journal when considering a) self-perceived level of knowledge, b) public vs private school, c) inclusion of a scientific literature appraisal subject in the curriculum, and d) progress in medical school.Results: Our sample included 770 valid responses, out of which most of the participants included were from Mexico  and Ecuador . Participants preferred using evidence-based clinical resources (EBCRs) to learn more about COVID-19 . The preferred study design was case report/series . We found that only 265 participants correctly identified the concept of a preprint (34.4%), while 243 students (31.6%) correctly identified the characteristics of a predatory journal. We found no significant differences in the proportion of correct answers regardless of the self-perceived level of knowledge, progress in medical school, or scientific literature critical appraisal classes.Conclusion: This study is novel in its approach of identifying sources of knowledge used by Latin American medical students and provides insights into the need to reinforce training in critical appraisal of scientific literature during medical school. Researchers throughout the globe have worked arduously to rapidly fill in the gaps of knowledge on this novel disease and this has resulted in an unprecedented surge in scientific production. However, the pressure of produce science quickly can cause an overproduction of low-quality research. Notably, before the pandemic, it was estimated that approximately 85% of research was wasted due to flaws in design, methodology or interpretation of the data, and these challenges have been augmented due to the time constraints and poor research infrastructure during the COVID-19 pandemic.,In December 2019, a cluster of cases of pneumonia of unknown origin was reported in Wuhan, China and since then, the virus has spread globally. On March 11, 2020, the World Health Organization (WHO) declared coronavirus disease 19 (COVID-19) as a pandemic., Medical students have helped during previous disasters and emergencies such as the Spanish flu outbreak of 1918 and the 1952 polio epidemic in Denmark; and they might have an important role during the COVID-19 pandemic through essential tasks such as assistance in clinical care, telemedicine, and fighting against misinformation.,The role of medical students has been diverse throughout history, from being participatory agents in the evolution of medical curricula to being agents of promotion, prevention and treatment of diseases.– Notably, the percentage of student authorship in published articles has increased importantly throughout the years.To provide high-quality healthcare services, future physicians should develop abilities to critically assess research to inform evidence-based decisions during their career, including critical appraisal of scientific literature within the curriculum of medical schools and promoting involvement in research opportunities could help students develop these skills.Due to their role, and the unprecedent low quality scientific information, it is indispensable that medical students have enough skills to analyse scientific data. In this study, we intend to identify preferred resources used by medical students in Spanish speaking countries in Latin America to obtain information about COVID-19 and evaluate basic critical appraisal skills through a self-report online survey.This study was approved by the Independent Review Board at Universidad San Francisco de Quito (2020-033M). Although data was anonymous and did not include identifying information, electronic informed consent was requested before the survey was collected. Participation was voluntary, and medical students were informed that data from the survey would be used for analysis and scientific publication. Participants did not receive any compensation from participating in the study.This was a multinational cross-sectional study based on a self-report online survey. Participants were medical students currently enrolled in a medical school in a Spanish-speaking country in Latin America. The inclusion criteria required for participation were that they were aged 18 or older, with active student status in a medical school based in a Spanish-speaking country in Latin America, and with Spanish language fluency. Exclusion criteria were non-active student status, medical students from a country where Spanish is not the primary language, and previous participation in the survey.As we intended to include participants from multiple countries and achieve significant variation in characteristics within our purposive sample, a link to the survey and an accompanying standardized text explaining the purpose of the survey was sent via e-mail from the authors to the initial “point of contact” in each country for further distribution following a snowballing approach. The link to the survey was then shared through different social networks by authors to medical students from their own and other medical schools, and authors instructed participants to share the link with their peers. The survey was distributed to students from different academic years to gather a diverse sample in terms of progress in medical school. We also actively tried to contact students from as many countries in Latin America as possible through e-mails sent to the medical students’ organizations publicly available to ask them to distribute the survey to their members. Data collection took place from October 22 to November 6, 2020. During the first week after the survey was released we obtained a huge amount of the answers, but then there was a very low number of new responses daily, therefore we decided to shorten the period for data gathering., Authors were invited to submit potential questions to a shared online document, which then underwent revision through a telematic session by all authors to determine the questions that would be included in the survey. The panel of authors included active students, alumni, and faculty with vast experience in medical education and research.We designed an electronic survey using the Google Forms web application. The survey consisted of fifteen closed-ended questions to gather basic demographic information and evaluate resources used to obtain information on COVID-19 and explore knowledge and attitudes that medical students had in terms of scientific information appraisal. The survey was developed by employing a conceptual framework, in which previous knowledge and experiences that authors had with publications related to medical education, as well as their personal experiences as medical students or faculty, guided the creation of questions.The survey was developed in Spanish and was reviewed by all authors to ensure that it was appropriate despite regional language variations. In addition, two independent academic advisors reviewed the survey for clarity. At this stage, no changes were required. Then, the survey was piloted in medical students from Ecuador (n=5), Mexico (n=3), and Argentina (n=2), who were mainly friends of the authors, to get their input and identify confusing or unclear questions. These surveys were not included in the analysis. Pretest resulted in minor changes, mostly related to grammar and punctuation After incorporating the feedback, we deployed the survey. As the survey was originally designed and applied in Spanish, we have included a translation to English which was performed by an author (BN) with certified proficiency and then by a native speaker who did not participate in the study .Data captured through the Google Forms web application was exported directly to Microsoft Excel (v. 16.58). An initial descriptive analysis of the responses to the survey to determine demographic characteristics and preferred resources used to gather COVID-19 related information was performed. All variables obtained in the results of the survey were analyzed. There was no missing data as the setting in the online survey did not allow for the submission of incomplete forms. We analyzed the difference in the proportion of correct identification of the concept of a preprint and predatory journals when comparing students based on their self-reported level of knowledge, progress in medical school, public vs. private status of medical school, and inclusion of a scientific literature critical appraisal subject during their curriculum. For data analysis, we decided to group low-medium and advanced-experts’ responses in the self-reported level of knowledge and first-second quarter and third-fourth quarter in progress in medical school responses to create dichotomized variables. Due to the categorical nature of our data, we decided to use Chi-squared tests. A one-tailed alpha value of 0.05 was set. All our statistical analyses were conducted on IBM SPSS version 25 .By incorporating different stakeholders in medical education , and researchers from different countries, we could design a study that contained different valuable perspectives on the critical appraisal of scientific information.Although ET is a professor in one of the medical schools where the survey was conducted, participants were not aware of his role in the research. No economic or academic incentive was offered by any of the authors to the participants.After data gathering, BN and DA performed an initial statistical analysis and shared the results with the other authors. A researcher not involved in this study was invited to validate the statistical analysis. Additionally, all authors had access to the database and agreed with the final data analysis and processing. Almost two-thirds of the participants were females . Most of the participants were from Mexico  and Ecuador . Students equally attended private  or public universities . We also found a similar distribution in terms of completed progress in medical school: 24.0% (n=185) in the first quarter, 24.3% (n=187) in the second quarter, 24.9% (n=192) in the third quarter, and the remaining 26.8% (n=206) in the final quarter of medical school. Distribution by gender and country is shown inThere were 770 valid responses to the survey .Most medical students considered that they had a low or medium level of knowledge about COVID-19 , while 231 participants reported an advanced or expert level (30.0%).Overall, medical students preferred using evidence-based clinical resources (EBCRs), such as UpToDate or Medscape, to learn more about COVID-19 , followed by academic journals , and open access courses provided by entities such as the World Health Organisation (WHO) . Our survey responses were grouped according to the different sub-regions of Latin America .Regarding the type of article, medical students preferred using case reports or case series  to learn more about COVID-19, followed by review articles  .The critical factor that medical students considered when reading a scientific article was most frequently the affiliation of the authors , followed by the journal of publication , the type of study , and the publication status (preprint vs. published) .In terms of receiving news related to the COVID-19 pandemic, medical students preferred official websites of organizations such as the WHO , followed by scientific journals , and medical platforms  .Additionally, relationship between percentage of undergraduate studies completed, self-perceived knowledge on COVID-19 and, source of preference for COVID-19 information were performed .We found that approximately a third of the participants correctly identified the concept of a preprint , while 243 students (31.6%) correctly identified the characteristic of a predatory journal. On the other hand, 553 students (71.8%) correctly identified the concept of an open-access journal.Two-thirds of the participants  had a subject focused on scientific literature critical appraisal as a part of their curriculum during medical school. We did not find a significant difference when comparing participants in terms of self-reported level of knowledge (low/medium vs advanced/expert) in the chance of correctly identifying the concept of a preprint  or a predatory journal .We conducted chi-squared tests to identify factors that were associated with a significant difference in the proportion of students that correctly identified the concept of a preprint or predatory journals (Extended data: Frequencies of answers and results of Chi-squares performed).2=11.063, P<0.01); however, there was not a significant difference while identifying the concept of a preprint .Participants from public schools correctly identified the concept of predatory journals  more frequently than students that attended a private medical school   or predatory journal  concepts regardless of the inclusion of a scientific literature critical appraisal subject during medical school. Finally, the proportion of participants that answered correctly was not significantly different for preprints  and predatory journals  despite the progress in medical school (first-second quarter vs third-four quarter).Additionally, we did not find significant differences in the correct identification of preprint  preferred evidence-based clinical resources (EBCR) for train and skill building. Notable, regardless of self-perceived knowledge of COVID-19, medical students preferred EBCR , which could be a way to combat the current misinformation outbreak (infodemic). Social media platforms provide users with immediate access to massive amounts of content and are the perfect medium to spread questionable information easily., It would be expected that medical students who had exposure to a subject focused on critical appraisal skills during their formation would choose study designs higher among the evidence pyramid, however, our results did not show a significant difference. These could be partially attributed to the fact that during the start of the pandemic most of the articles published were retrospective studies or case reports focusing on patients’ characteristics. Remarkably, we found that regardless of the progress in medical school, self-perceived level of knowledge about COVID-19, and the inclusion of a critical appraisal subject in the curriculum, most of the participants could not correctly identify the concept of a preprint or a predatory journal, despite the enormous surge in preprint production during this pandemic. As well, in our study, only 44 participants (5.71%) chose the publication status (preprint vs published article) as a critical factor when reading an article. Overall, regardless percentage of career completed, or self-perceived level of COVID-19 knowledge medical students take into consideration as main critical factor to read an article endorsement from institutions . Scientific literacy and preferred resources used by Latin American medical students during COVID-19 pandemic.•Survey results-Scientific literacy and preferred resources used by Latin American medical students during COVID-19 pandemic. .•Frequencies of answers and results of Chi-squares performed. This project contains the following underlying data:Creative Commons Zero “No rights reserved” data waiver (CC0 1.0 Public domain dedication).Data are available under the terms of thehttps://doi.org/10.17605/OSF.IO/7MS64.Open Science Framework (OSF). Scientific literacy and preferred resources used by Latin American medical students during COVID-19 pandemic.•Infodemic survey English version. •Infodemic survey Spanish version. This project contains the following extended data:Creative Commons Zero “No rights reserved” data waiver (CC0 1.0 Public domain dedication).Data are available under the terms of the I feel that the revision is satisfactory and I have no more comments.Is the work clearly and accurately presented and does it cite the current literature?YesIf applicable, is the statistical analysis and its interpretation appropriate?PartlyAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?PartlyAre sufficient details of methods and analysis provided to allow replication by others?PartlyReviewer Expertise:PsychosocialI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. The authors made changes that resolved minor drawbacks found in the first version of the article. In my opinion, the current version is adequate, the information provided is relevant and the reading of the text leads to important insights on aspects of medical education and the use of adequate information sources by medical students in Latin America.Is the work clearly and accurately presented and does it cite the current literature?YesIf applicable, is the statistical analysis and its interpretation appropriate?YesAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?YesAre sufficient details of methods and analysis provided to allow replication by others?YesReviewer Expertise:Virology, infectious diseasesI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. The issue of information quality proved to be extremely relevant in the context of the COVID-19 pandemic, especially during the first year. An infinity of obscure sources of information, including from social networks to a profusion of material published without any type of quality review, gave the opportunity for untruths to be raised to the level of scientific knowledge, greatly harming the fight against the pandemic in many scenarios. In this sense, the study becomes relevant and very interesting to assess the levels of understanding of medical students at different levels of training, about what they consider reliable sources of information, and how they judge dubious sources. From the point of view of minor points that require further investigation, it would be interesting to clarify and discriminate more clearly how students have judged the diverse types of information sources, depending on their level of completion of the medical curriculum, from the beginning to the end of graduation, and how this does evolves or not throughout.Is the work clearly and accurately presented and does it cite the current literature?YesIf applicable, is the statistical analysis and its interpretation appropriate?YesAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?YesAre sufficient details of methods and analysis provided to allow replication by others?YesReviewer Expertise:Virology, infectious diseasesI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. - From the point of view of minor points that require further investigation, it would be interesting to clarify and discriminate more clearly how students have judged the diverse types of information sources, depending on their level of completion of the medical curriculum, from the beginning to the end of graduation, and how this does evolves or not throughout. We thank you Professor Spilki for his comments and regarding his suggestion, in the new version, this information has been added to new table 4. The survey was designed specifically for this study by the authors; they included active students, alumni, and faculty with vast experience in medical education and research." Is this an expert panel that discusses the survey questions? Or, is this an informal chat between the authors and all the other stakeholders? Accordingly, it is unclear what the purpose of pilot testing on the medical students is. The authors mentioned that they wanted to get "input" from the piloted medical students. However, it is unclear what "input" the authors wanted to get. I suspect that the authors did not provide proper instructions to these students and thus they only obtained some minor comments. Also, it is unclear what the background of these students was .Please elaborate on how the 15 closed-ended questions were generated. It is unclear where the 15 questions come from. Did the authors conduct a literature review to identify potential items and then reduce the items via expert panels? It is also unclear what the following procedure is: "The authors only used chi-squared tests for all the inferential statistics. Only using chi-squared tests has the problem of not controlling potential confounders. Given that the sample size was large, the authors should be able to apply multivariable statistics that control potential confounders .I wonder how representative the sample was. Specifically, does the demographic distribution of the present sample similar to these surveyed countries? I found that it is interesting to have a higher proportion of females. Following the previous comment, I wonder how the authors ensure if the participants were the target participants. For example, maybe a student who was not a medical student received the email and completed the survey. Can the authors catch these invalid responses?Given that health literacy on COVID-19 is the key information in the present study, I think that the authors should examine other potential factors on the COVID-19 literacy. Specifically, why don't the authors examine if the resources obtaining COVID-19 knowledge is a factor explaining the student's COVID-19 knowledge? Similarly, it would be interesting to examine if different types of articles the students read play a role in their COVID-19 knowledge. I disagree with the statement "The main limitation to our study is the sample size". Specifically, the entire sample size is good, and the problem is that the authors had an imbalanced sample size. After all, the authors did not separate the participants into different countries for the data analysis. Therefore, the authors did not have the problem of a small sample size in statistics. The manuscript can be improved with the following considerations:Is the work clearly and accurately presented and does it cite the current literature?YesIf applicable, is the statistical analysis and its interpretation appropriate?PartlyAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?PartlyAre sufficient details of methods and analysis provided to allow replication by others?PartlyReviewer Expertise:psychosocialI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Please elaborate on how the 15 closed-ended questions were generated. It is unclear where the 15 questions come from. Did the authors conduct a literature review to identify potential items and then reduce the items via expert panels? It is also unclear what the following procedure is: "The survey was designed specifically for this study by the authors; they included active students, alumni, and faculty with vast experience in medical education and research." Is this an expert panel that discusses the survey questions? Or, is this an informal chat between the authors and all the other stakeholders? Accordingly, it is unclear what the purpose of pilot testing on the medical students is. The authors mentioned that they wanted to get "input" from the piloted medical students. However, it is unclear what "input" the authors wanted to get. I suspect that the authors did not provide proper instructions to these students and thus they only obtained some minor comments. Also, it is unclear what the background of these students was . Thank you for your comment. This has been improved in v2 of our manuscript. Briefly, potential item were obtained either from literature or previous experience. As most of the authors were not experts in the field, the survey questions were defined through informal chat between the authors and other stakeholders. The pilot testing was a strategy to ensure the questions were fully understood or to get feedback to improve it. In fact, they were very well instructed about their role, not only in the answer as potential participants.The authors only used chi-squared tests for all the inferential statistics. Only using chi-squared tests has the problem of not controlling potential confounders. Given that the sample size was large, the authors should be able to apply multivariable statistics that control potential confounders .   We thank you Professor Chung-Ying Li for his suggestion. However, as all our data is qualitative, after consulting with our advisor in statistics, could not find any added value to applying multivariable analysis.I wonder how representative the sample was. Specifically, does the demographic distribution of the present sample similar to these surveyed countries? I found that it is interesting to have a higher proportion of females.   Results section, according to our knowledge, the distribution of the data is consistent with other Cross-Sectional studies performed in Latin America Region. Therefore, yes, our sample was representative. In the same sense, we initially had the same concern that reviewer 1 regarding the gender distribution. However, once again, in most of these kinds of studies, females are more active in response. As was described in the Following the previous comment, I wonder how the authors ensure if the participants were the target participants. For example, maybe a student who was not a medical student received the email and completed the survey. Can the authors catch these invalid responses?    Given that health literacy on COVID-19 is the key information in the present study, I think that the authors should examine other potential factors on COVID-19 literacy. Specifically, why don't the authors examine if the resources obtaining COVID-19 knowledge is a factor explaining the student's COVID-19 knowledge? Similarly, it would be interesting to examine if different types of articles the students read play a role in their COVID-19 knowledge.  It is important to mention that although the collection of data was performed through an online survey, and the risk of someone outside the target population might answer the survey, we consider that this risk was reduced by employing a chain-referral method with other medical students.Table 4 and discussion section. This analysis was performed to study if the behavior among medical students changes along with the progress of their career or the level of auto perception in knowledge choosing better sources to acquire medical knowledge. To explore other factors that could contribute to Covid-19 literary among medical students, we perform an additional descriptive analysis where we make a relationship between the percentage of undergraduate studies completed, self-perceived knowledge on COVID-19, and source of preference for COVID-19 information that is summarized inI disagree with the statement "The main limitation to our study is the sample size". Specifically, the entire sample size is good, and the problem is that the authors had an imbalanced sample size. After all, the authors did not separate the participants into different countries for the data analysis. Therefore, the authors did not have the problem of a small sample size in statistics. We agree with Professor Chung-Ying Li that the correct term is not a sample size, instead, we change the term toimbalanced sample size.


Indoor 3D positioning is useful in multistory buildings, such as shopping malls, libraries, and airports. This study focuses on indoor 3D positioning using wireless access points (AP) in an environment without adding additional hardware facilities in large-scale complex places. The integration of a deep learning algorithm into indoor 3D positioning is studied, and a 3D dynamic positioning model based on temporal fingerprints is proposed. In contrast to the traditional positioning models with a single input, the proposed method uses a sliding time window to build a temporal fingerprint chip as the input of the positioning model to provide abundant information for positioning. Temporal information can be used to distinguish locations with similar fingerprint vectors and to improve the accuracy and robustness of positioning. Moreover, deep learning has been applied for the automatic extraction of spatiotemporal features. A temporal convolutional network (TCN) feature extractor is proposed in this paper, which adopts a causal convolution mechanism, dilated convolution mechanism, and residual connection mechanism and is not limited by the size of the convolution kernel. It is capable of learning hidden information and spatiotemporal relationships from the input features and the extracted spatiotemporal features are connected with a deep neural network (DNN) regressor to fit the complex nonlinear mapping relationship between the features and position coordinates to estimate the 3D position coordinates of the target. Finally, an open-source public dataset was used to verify the performance of the localization algorithm. Experimental results demonstrated the effectiveness of the proposed positioning model and a comparison between the proposed model and existing models proved that the proposed model can provide more accurate three-dimensional position coordinates. Since the concept of Industry 4.0 was proposed, location-based services (LBS) have attracted significant attention because of their social and commercial value  and the Industries and academia have devoted themselves to research on indoor positioning technology and methods. In the past decade, the number of papers published in the field of indoor positioning has rapidly increased and many wireless technologies have been studied for indoor positioning, including ultrasonic, Bluetooth, radio frequency identification (RFID), ultra-wide bandwidth (UWB), and WiFi technologies. The advantages, disadvantages, and positioning accuracies of these techniques are summarized in Among these technologies, ultrasonic, RFID, UWB, Bluetooth, infrared, and ZigBee indoor positioning techniques require specific hardware support and several positioning beacons, such as infrared, ultrasonic, or RFID beacon whilst WiFi is the most widely deployed indoor wireless infrastructure . The Wi-The remainder of this paper is organized as follows. The fingerprint positioning method must construct a fingerprint map in advance from the target area  and a poFor the study of 3D positioning, Sospedra et al. proposed the first open-source multifloor location fingerprint dataset and adopted the KNN method . Nguyen Another method for constructing fingerprint maps is to use continuous data. This approach involves collecting fingerprints along the trajectory sequentially and recording the location information of the sampling points. The collected fingerprints contained temporal information and the historical information of the walking trajectory can be used to enhance position estimation. Au et al. used a Kalman filter for continuous localization which requires the assumption of Gaussian noise distribution and linear motion . Hoang pFrom the research mentioned above, it can be observed that deep learning can be used for indoor positioning to improve positioning accuracy as illustrated in In summary, research on indoor positioning has primarily focused on two-dimensional (2D) plane positioning, however, in practical application scenarios, most are multifloor environments, where 2D position coordinates cannot determine the location of the target, and it is necessary to obtain the vertical dimension information, floor, or height of the target in the building. In addition, the traditional location algorithm only considers the position matching of a single fingerprint and ignores the correlation between fingerprint sequences. The current position of the target is related to its historical position. Therefore, it is necessary to develop an indoor 3D positioning model that considers spatiotemporal data. Deep learning, which can be used in 3D positioning model design, has been an effective tool for data analysis in recent years.This study proposed an indoor 3D positioning algorithm called TCN_DNNLoc, which is a hybrid algorithm combining TCN and DNN. The proposed algorithm is divided into an offline model training stage and an online fingerprint matching stage. The framework is illustrated in In the offline stage, the temporal fingerprint map is constructed, the 3D positioning model is trained and the fingerprint data are collected in a continuous manner. WiFi fingerprints are collected along the trajectory and the corresponding 3D position coordinates of the collected points are recorded, along with the collected time stamp. Then, the fingerprint map is preprocessed and the RSSI in the fingerprint vector is converted to a number between 0 and 1 for improving the learning ability of the model. Next, a fixed-length sliding time window is used to construct temporal fingerprint slices, which are used as the input of the model, and the TCN feature extractor is used to learn the hidden information and temporal relationship in the input data. Finally, the extracted spatio-temporal features are transmitted to the DNN position regressor for nonlinear mapping of temporal features to 3D coordinates, and the training set is used for model training.In the online fingerprint-matching stage, the positioning model is first loaded. The collected fingerprint is used to construct the timing fingerprint slice, which is input into the positioning model to realize end-to-end 3D position coordinate prediction. Finally, the positioning result is sent back to the user.In the following sections, a temporal fingerprint map and its pre-processing method are introduced. Subsequently, a temporal fingerprint slice construction method based on a sliding window is discussed. Next, a fingerprint spatial and temporal feature-learning model based on the TCN is proposed, and finally, the proposed TCN_DNNLoc 3D temporal fingerprint positioning algorithm is introduced in detail.A 3D temporal fingerprint map is constructed continuously. The timestamp, WiFi fingerprint vector, and corresponding 3D position coordinates are recorded by continuous sampling along the trajectory at a certain time interval. The 3D temporal position fingerprint map data are listed in t can be expressed as shown in (1):MAC address of the ith AP in an environment. The MAC address is a unique AP identifier and ith AP at time t. The closer it is to the AP, the greater the RSSI value.The WiFi fingerprint vector collected at time t and t. The 3D position vector is defined as shown in Equation (3):The temporal fingerprint map is defined as shown in (2):t based on the current and previous fingerprint vectors, as shown in Equation (4).A temporal fingerprint-based indoor positioning problem can be formulated as a sequence learning problem that predicts the user’s 3D position vector Here, c is a constant value that should be set to a number less than or equal to the minimum RSSI value to move the RSSI value to a positive range. The zero-one normalization representation performs a linear transformation of the original RSSI and normalizes the RSSI value after moving it to a positive range. The RSSI is more likely to have signal fluctuations when it is far from the AP. Consequently, the exponential representation and power representation perform nonlinear transformations on the RSSI and add penalties for higher RSSI values. The denominator parameter α is set to a constant and the exponential parameter β is generally set to a mathematical constant e. After preprocessing, the RSSI value was converted to a value between 0 and 1. An RSSI value close to 1 indicates a stronger signal and 0 indicates an undetected AP.This section describes the process of preprocessing WiFi RSSI. Through preprocessing, the RSSI value can be converted to a number between zero and one, which is helpful in improving the learning ability of the neural network model. Related studies have proved that WiFi RSSI preprocessing has a significant impact on positioning performance. Nurpeiissov et al.  proposedc was set to −100 in this study. The experimental results are shown in Preprocessing of the WiFi RSSI has a significant influence on positioning accuracy. For the IMUWIFINE dataset  used in Traditional positioning algorithms use a single fingerprint as the model input. Owing to the noise and redundancy in WiFi fingerprints, fingerprints collected for the same location may not be the same. Additionally, once the points that are far away from each other in the physical space have a high similarity in the signal space, it will affect the positioning accuracy. A sliding time window to build a temporal fingerprint chip as the input of the positioning model to provide abundant information for positioning. Temporal information can be used to distinguish locations with similar fingerprint vectors and to improve the accuracy and robustness of positioning.In this study, a fingerprint vector sequence is selected as the input of the model. Temporal fingerprint slices are constructed by window sliding, where the size of the sliding window was set as The reconstructed fingerprint slice dataset using the sliding window is shown in The model architecture is shown in Series_FP =  is used as the input of the model. Series_FP is a two-dimensional matrix of W × N. W indicates the sequence length of time, which is equal to the size of the sliding window. Here, N indicates the total number of AP in the environment. The fingerprint slice contains a fingerprint vector collected continuously over time, W. The location label corresponding to the fingerprint slice is t.The fingerprint vector of a single strip is easily affected by the dynamic changes in the environment and the inherent noise of the signal; therefore, the fingerprint slice Series_FP, as shown in Equation (8) and The TCN feature extractor with three residual blocks is used to extract the features of The specific architecture of residual blocks is shown in Each residual block contained two layers, namely: causal and dilated convolutions. Through the causal convolution mechanism, causal constraints are added, and the connections that do not meet the temporal dependence are removed in the training and learning processes. Through the dilated convolution mechanism, larger receptive fields of information are obtained without increasing the number of network layers. The weight-normalized layer is added after each causal and dilated convolution layer to speed up model convergence. The ReLU activation layer activates neurons nonlinearly and adds nonlinear factors to the model to improve its feature learning ability. The Droupout layer sets the loss rate to inactivate neurons proportionally and at random to avoid an excessive fitting model. This is discussed in detail in the next section.The framework of the TCN feature extractor is shown in After extracting spatio-temporal features, the TCN feature extractor is connected to the DNN regressor with two hidden layers to learn the nonlinear mapping between spatio-temporal features and 3D positions, as shown in ST_Features vector is passed forward to the DNN regressor with two hidden layers, as shown in Equations (9)–(12):The Here, After passing through two fully connected hidden layers, information is transmitted to the output layer with three neurons, which do not use the activation function, as shown in Equation (13):The t, t. An Adam optimization was used to update the parameters.The mean square error was used as the loss function of the model, as shown in Equation (14):The experiment used the IMUWIFINE dataset  launchedSpecific attribute information for the dataset is presented in The 3D average error distance and cumulative error distribution functions were used as the performance evaluation indexes of the model. dist is the Euclidean distance between the actual position The definition of 3D average error distance is shown in Equation (15):dist is defined as in Equation (16):The The cumulative error distribution function (CEDF) is another evaluation index and the trend in the error distribution curve indicates the overall error distribution. The faster the curve rises, the better the positioning effect.To improve the performance of the positioning model, the TCN feature extractor and DNN position regressor were optimized.The number of convolution kernels in the TCN feature extractor affects the spatiotemporal feature extraction, which in turn affects the accuracy of the model. This study tested the effect of the TCN with different numbers of convolution kernels. The experimental comparison results are shown in Initially, with an increase in the number of convolution kernels, the positioning precision of the model was greatly improved. The best positioning effect was obtained by using 128 convolution kernels. As the number of convolution kernels continued to increase, the model positioning performance decreased. Additionally, when the number of model parameters increased dramatically, the training time became significantly longer. Consequently, the number of convolution kernels in the TCN space-time feature extractor was set to 128.For DNN regressors, different network structures affected the performance of the model. The experimental comparison results are shown in It can be observed that the performance of a single hidden layer was limited. However, increasing the number of network layers can cause overfitting and affect the positioning performance of the model. In the experiment, 128–128 means that two hidden layer structures with 128 neurons were adopted; this selection yielded the best positioning performance. This study adopted a sliding window to build the temporal fingerprint slice where the length of the temporal fingerprint slice was equal to the size of the sliding window. The longer the series, the more historical information it contains but the more cumulative errors it introduces. To balance these two points for the optimal time series length, experiments were conducted with different series lengths. The positioning errors for the different series lengths are shown in The minimum average error distance was obtained when the time-series length was eight. The cumulative error distribution curves for different time-series lengths are shown in In summary, parameter settings of TCN_DNNLoc algorithm are shown in The performance of the proposed TCN_DNNLoc model was compared with the nonsequential model SRL_KNN , FNN 2121, and sThe 3D positioning errors of different models are shown in It can be observed from the figure that the positioning accuracy of the sequence model is significantly higher than that of the nonsequence positioning model. For the comparison between the two sequential models, the 3D average error distance of the positioning model based on LSTM was 1.33 m, and the 3D average error distance of the TCN_DNNLoc was 1.22 m, an accuracy improvement of 7.5%. The cumulative error distribution curves for the different models are shown in It can be observed from In our daily life, 3D indoor positioning is of great significance. It can not only help people navigate in multi-story buildings, but also help managers to count the distribution of people flow in the buildings. At present, it can also help to control the spread of COVID-19 more accurately. This study reviewed relevant references and comprehensively analyzed existing positioning techniques and methods. We focus on the WiFi fingerprint method because of its wide deployment in multi-story buildings. Compared to a single fingerprint input, the fingerprint sequence collected continuously contains historical data, which can provide richer information for positioning. Temporal information can be used to distinguish positions with similar fingerprint vectors and improve the accuracy and robustness of mobile positioning. Based on previous studies, this study applied deep learning techniques to the indoor positioning field and proposed a new sequence-positioning model called TCN_DNNLoc. In the proposed model, the sliding time window method is used to construct temporal fingerprint slices, which are used as the input to the model, to provide richer information for positioning, solve the problems of environmental noise and spatial ambiguity, and improve the accuracy and robustness of positioning. A TCN spatiotemporal feature extractor was proposed to extract the sequence fingerprint slice of hidden information and temporal relations. The proposed TCN model adopts causal convolution, dilated convolution, and residual connection mechanisms, and is not restricted by the size of the convolution kernels. The proposed model also expands the receptive with long history information, compact structure, and reduced parameters, and solves the problems of gradient disappearance and gradient explosion. The extracted spatiotemporal features are connected to a deep neural network (DNN) position regressor, and the complex nonlinear mapping relationship between the features and 3D position coordinates is learned to estimate the 3D position coordinates of the target. The effectiveness of the TCN_DNNLoc model was proved by an experimental comparison with the existing 3D method.(1)The positioning accuracy was affected by the connection weight and bias of the model. Future research should consider using a heuristic algorithm to optimize the parameters. Examples include the genetic algorithm (GA) , particl(2)This study considered only WiFi technology for positioning; however, each positioning technology has its own characteristics and limitations. With the development of microelectric systems, the accuracy of sensors has improved continuously, whilst the built-in sensors of mobile phones, such as air-pressure sensors and accelerometers, can be used for auxiliary positioning. Future research must consider the integration of WiFi technology with other technologies to provide more accurate positioning information. Multi-technology fusion and mutual learning can compensate for the limitations of single-positioning technology and improve positioning accuracy.There are two future research directions of this study:


Structural health monitoring systems for composite laminates using guided ultrasonic waves become more versatile with the structural integration of sensors. However, the data generated within these sensors have to be transmitted from the laminate to the outside, where polyimide-based printed circuit boards play a major role. This study investigates, to what extent integrated polyimide inlays with applied sensor bodies influence the guided ultrasonic wave propagation in glass fiber-reinforced polymer specimens. For reasons of resource efficiency, narrow specimens are used. Numerical simulations of a damping-free specimen indicate reflections of the  Structural health monitoring (SHM) using guided ultrasonic waves (GUW) has been of great interest in research for the detection of structural damage ,2,3,4. GTo obtain information about the wave propagation within the structure, it is useful to integrate sensors at the location of the event. In a previous work, the authors presented a novel embeddable microelectromechanical system (MEMS) vibrometer made mainly out of borosilicate glass for GUW detection . HoweverThe characteristics of wave field interferences with damage are extensively investigated in the literature. Typical types of damage include cracks, corrosion, impact, delaminations and through-holes. Within the classical approach, which is usually referred to as linear wave propagation, the detection of damage smaller than the wavelength is not possible . Due to As shown, there is extensive work on the interference between damage and GUW whereas the influence of integrated sensors is hardly addressed. In contrast to discrete sensors, the integration of optical fiber sensors  and fibeIn contrast, the integration of discrete sensors requires more profound research and can be divided into attempts for single sensors and for sensor networks. Single sensors can be integrated quite well without affecting their performance and without weakening the structure substantially. This is investigated for three-point bending and fatigue tests and is confirmed in the presence of damage to the structure ,31. AnotTo evaluate a monitoring system with integrated sensors, the influence on the mechanical properties has to be taken into account. An abundance of research addresses the integration of lead zirconate titanate (PZT) sensors in carbon fiber-reinforced polymer (CFRP). The integration of single sensors shows no influence on the fatigue strength , but theAlthough the integration of sensors shows no significant degradation of the structure’s mechanical properties, a difference in performance between surface-bonded and embedded transducers might occur. A comparison of emitter–receiver combinations in GFRP shows that there are configurations where embedding both the emitter and receiver provides the best signals, even compared to two surface-bonded transducers . This beExperimental setups used to determine wave characteristics need well-defined boundary conditions and a wave field with as little disturbances as possible. Normally, the largest possible specimens are chosen to avoid reflections from the edges and their superposition with the signal of interest. However, large specimens increase manufacturing effort, costs and material consumption. Narrow specimens avoid these drawbacks while showing a more complex wave field. The suitability of strip-like specimens to investigate GUW propagation is subject to current research. An investigation looked at whether a narrow isotropic aluminum specimen could be simplified as a 1D structure and used to generate a straight wave front. The propagation of flexural and axial waves was numerically simulated in a 14 ip’s end . Increas’s edges . One str’s edges .In summary, on the one hand, the literature review presents investigations on GUW interaction with damage. On the other hand, the performance of integrated discrete sensors for SHM applications using GUW is investigated. However, the influence of the sensor and corresponding electrical contacting integration on the wave field has not yet been sufficiently addressed. In addition, the geometry of a possible sensor is of interest.The aim of this paper is to investigate the influence of an embedded sensor that is presented by the authors  and mounThis work shows that the integrated inlays cause reflections that cannot be experimentally detected and are therefore assumed not to influence the wave propagation significantly. However, reflections from the specimens’ edges do occur and superimpose with the propagating waves. In this study, a method is presented to distinguish between edge reflections and the interactions at integrated inlays using the periodic behavior of the occurring wave packages. This method includes a spatial continuous wavelet transformation to identify the different kinds of reflections in the time–space domain of the transformation and to assign the observed wave packages to specific wave modes.Hence, this article is structured as follows. The materials and methods section starts with the design of the GFRP specimen with an integrated sensor inlay and an estimation of the related dispersion relation. The numerical model to deduce possible wave interactions between GUW and the inlay is presented. This is followed by an introduction of the experimental setup of the air-coupled ultrasonic technique and a 3D laser Doppler vibrometer (LDV) measurement. The methods section closes with a description of the continuous wavelet transformation (CWT) used to evaluate the experimental data. Subsequently, the numerical and experimental results are presented. Regarding the extracted B-scans of the measurement, possible reflections in the wave field are discussed. Subsequently, the CWT is used for time signal reconstruction to identify reflected wave packages. The work closes with a discussion of the results including a critical analysis of the experimental procedures and a comparison between the numerical and experimental results.Considering the possible integration of sensors into plate-like structures for SHM using GUW, a simplified approach is followed. As already mentioned, the sensor investigated is a MEMS vibrometer composed mainly out of borosilicate glass . As no sFollowing this procedure, six different strip specimens are manufactured. An overview of the specimens’ inlay specifications is given in For the design of the strip specimens, we employed the unidirectional GFRP prepreg DLS1611 from Hexcel Corp. The fiber orientation is chosen to be perpendicular to the strip specimen’s length since the lower stiffness in this direction leads to smaller velocities. The aim is to selectively reduce the propagation velocities in the direction of the strip specimen’s length by design. The dispersion relation for a laminate setup offers information about the expected modes’ phase velocities as shown in To analyze the impact of sensor inlays on GUW propagation without any experimental side effects, numerical simulations are first conducted as a preliminary investigation. The numerical simulations are not meant to represent the subsequent experiments in their entirety, but to instead provide a qualitative impression on what to expect during the LDV and air-coupled measurements.For the finite element simulation, a two-dimensional model, cf. In the numerical simulation, the wave field is excited by a five-cycle Hanning windowed sine burst with a center frequency of 75 To ensure correct simulations of the wave propagation in the composite, a sufficient spatial discretization ns apply ,44(1)ΔtHowever, the discretization of the model depends not only on the wavelength of the wave modes, but also on the layered structure of the waveguide. Due to the thin polyimide layer relative to the overall specimen thickness, the selected element edge length is much smaller than the required value following Equation . FurtherThe numerical simulations are conducted in COMSOL Multiphysics. With the presented discretization, the computation time of the wave propagation in GFRP with a polyimide inlay takes approximately 6 h.To analyze the detectability of the wave interaction with the polyimide inlay in real specimens, two independent experimental procedures are performed. As in the numerical simulations, B-scans are extracted as a representation of the wave field along the path from the actuator to the inlay. This method is performed for both experiments. In the first run, the wave propagation is measured using an air-coupled ultrasonic technique. All six specimens are examined with regard to a possible reflection phenomenon at the polyimide inlay. In a second run, a 3D LDV measurement is used at different excitation frequencies for one specimen. The two different measurement procedures allow the experimental separation and evaluation of the different displacement field components. Details of the two procedures are described in the following.The air-coupled ultrasonic technique is an established method in non-destructive testing and the setup in this study is exemplary, shown in A round PZT ceramic . All measurements are averaged eight times.Variations in probe angle allow for the detection of different components of the excited wave modes. Therefore, two probe angles are chosen: probe perpendicular to the strip specimens and a probe angle of approx. 10° to the vertical. Using the probe perpendicularly allows the detection of the pure out-of-plane component of the displacement field, while using the probe under a certain angle detects a superposition of out-of-plane and in-plane components of the propagating waves.The aim of the 3D LDV measurement is the extraction of the in-plane and out-of-plane components of the wave propagation to allow separate evaluation  and bettThe excitation signal is a five-cycle Hanning-windowed sine burst signal that is amplified by a high-voltage amplifier WMA-300 . In reference to the simulation described in Prior to the investigations, a rectangular actuator (material: PIC255, width: 50 The measurement path is depicted in Retroreflective tape is applied to the specimen’s surface along the measurement path to increase the signal quality of the LDV measurement. Three subsequent measurements are performed at different angles and a coordinate transformation is implemented to decompose the measured surface velocities into one out-of-plane and two in-plane components ,45.In the results section, a clear identification of wave packages according to their occurrence in space and time by means of examining their wavelength is necessary. Within this work, a continuous wavelet transformation is used for this purpose.A wavelet transformation offers the possibility to extract information about the occurring frequencies in a time signal over a localization in the time-domain. Hence, it is a method of direct time-frequency analysis, which works using a time-limited window with an average amplitude of zero and a variable size . A singlThe CWT of a time signal leads to a representation of the energy distribution per frequency in the time-domain . Since tIn this study, the experimental time signals are filtered using CWT in the time-frequency domain. They are reconstructed using the inverse CWT with a narrower frequency bandwidth set to ±5 The results of the numerical simulations are provided in ructures . InsertiTo gain a deeper insight into the influence of the inlay on wave propagation, In conclusion, an interaction between the excited GUW and the polyimide inlay is found for a certain frequency range. Both the fundamental Measurements by means of the air-coupled ultrasonic technique as presented in Exemplary for all measurements and in reference to the numerical simulations described in The measurement path described in To separately evaluate the in-plane and out-of-plane component of the wave propagation, the results of the 3D LDV measurement as described in The wave propagation speed of the It can be seen in all figures that no reflections at the polyimide inlay can be identified. Instead, wave packages occur that cannot be directly linked to the propagating The wave packages’ variation in amplitude along the B-scans can be explained by the periodic superposition of back and forth running waves between the narrow edges of the specimen causing standing waves to superpose the GUW. This will be verified in the following section using a continuous wavelet transformation as described in In this section, a spatial CWT is used to identify the occurring wave packages described in We investigated whether the wavelength of the Due to the multimodal and dispersive behavior of the GUW, it is expected that the transformed signals in the wavelength–space-domain will not appear in clear delineation.In the following, a complete analysis for the measurement at 75 The results of the spatial CWT for 75 At 40 At an excitation of 120 As shown in For all frequencies, a spatial CWT can be used to show that the periodically occurring wave packages have the wavelength of the This section discusses the methods and results presented above to assess whether reflections at the integrated polyimide inlays occur and affect the wave field.The numerical simulations indicate that reflections of the However, independently of the sensor body’s shape, no reflections are detected by the air-coupled ultrasonic technique. In contrast to the polyimide inlay, the sensor bodies representing the MEMS vibrometers under investigation  are smalAlthough the numerical simulation predicts the highest reflection amplitude for the in-plane component, this cannot be validated experimentally. By extracting the corresponding motion with a 3D LDV measurement, no reflections are detected in specimens with embedded polyimide inlays. It is concluded that material damping effects of the epoxy resin occur to such an extent that reflections in the experiments are attenuated below the detection threshold.Despite using a rectangular PZT actuator, periodically appearing wave packages are detected. However, by performing a spatial and temporal CWT, they can be identified as Therefore, regarding the narrow GFRP specimens at hand, the GUW experiments and methods used can be successfully performed and reveal no detectable GUW reflections at the integrated polyimide inlays.This leads to the conclusion that polyimide inlays are suitable as PCB substrates for integrating sensors such as MEMS vibrometers  into FRPThe aim of this work is to investigate the influence of integrated sensor substrates on the GUW propagation in FRP specimens. Here, a thin and narrow polyimide inlay serves as the substrate for a PCB with applied representation of a MEMS vibrometer .Initial numerical simulations in an undamped model show reflections at an amplitude of at least an order of magnitude smaller than the incident wave. In a 3D LDV experiment, reflections from the specimens’ edges can be clearly identified with a spatial-temporal CWT due to their localization in space and time. Since they show a clear periodical behavior, they can be distinguished from possibly detectable inlay reflections which leads to the conclusion that polyimide substrates can be used for PCBs to integrate GUW sensors inside FRP without influencing the wave propagation in a detectable manner. As a main advantage of this study, reflections from the specimens’ narrow edges can be clearly identified using easy-to-implement signal transformation methods. However, conclusions on other laminate structures and strip geometries require further investigation.Future studies will investigate the extent to which other variables influence the results obtained in this work. Possible investigations can be performed regarding different fiber materials, i.e., 3D woven fabrics, fiber orientations, laminate setups, ambient temperatures, polyimide thicknesses and different sensor materials. Further investigations within the framework of a parameter study are being sought. The sensor is to be accounted for in the numerical model and the simulation results are to be compared.


Despite controversy regarding its validity and clinical usefulness, manual examination findings still have an important role for manipulative therapies. As an example, somatic dysfunction (SD) remains central to osteopathic practice.This study aims to explore the experienced osteopaths' attitudes concerning SD and its role in osteopathic practice. This qualitative research could contribute to building a consistent paradigm for manual intervention in all musculoskeletal manipulations.A thematic analysis with grounded theory elements was used. Data were collected through semi-structured interviews carried out between February and April 2021. A purposive sample of twenty professional osteopaths with past experience in osteopathic care was chosen to reflect the phenomenon's variety. The data analysis was done inductively and in tandem with the recruiting to keep track of data saturation.Eleven osteopaths participated in the study. Three main themes emerged from the data analysis: (1) SD as a safe tissue-touch-based communication tool between operator and person complex adaptive health system; (2) The treatment of SD is shareable between osteopaths, other health professionals, and the patients involved in the therapeutic pathway improving body awareness and health; (3) The development of the SD concept in research and practice to better clarify osteopathic profession identity and definition.A panel of expert osteopaths consider the concept of SD as a valuable tool integrated into the osteopathic evaluation and treatment process. The shared concept and clinical application of SD is informed by person-centered care concepts and from the fields of neuroscience, cognitive and complexity science. Our study reports a common need among osteopaths to develop an evidence-based framework of SD to allow the best development of the osteopathic profession.The online version contains supplementary material available at 10.1186/s12998-022-00444-2. Manual and musculoskeletal therapists  apply various hands-on\hands-off or through equipment interventions on the whole body framework to meet the patients’ need improving health,circulation, relieve fatigue and promote healing .Nowadays, there is an emergent debate about the reconceptualization of the value of manual examination and palpatory findings generally used by manual therapists , chiroprArticular or neural manipulative techniques have been linked to biomechanical rationale effects, even if their association with clinical results is controversial , 6. WhatIn the field of manual therapy a current model suggests that the mechanical force from a manual therapy intervention results in systemic neurophysiological responses leading to pain inhibition , 6, 8. WIt matters because nowadays it is well known that musculoskeletal pain conditions are a result of a complex interaction of biological, and psychological factors and cannot be resolved by addressing structural dysfunction/impairment alone. There is a need for manual therapies, such as osteopathy and chiropractors to move beyond structural impairments and achieve a renovated shared paradigm for musculoskeletal pain care. There is an existing empirical and theoretical gap in the literature that needs to be better articulated to serve as rational for future study and creates a springboard for a renovated model underlying palpatory finding and their use in manual therapies. There are recommendations to advance the study of palpatory findings and conceptual models for manual therapies  that incOsteopathic care uses manual techniques to support individual psychophysiological adaptation . The treThe international osteopathic community is now facing a growing debate on the role of SD in osteopathic practice and professional identity –20. TherSeveral studies proposed theoretical frameworks for SD , 23–28. Considering the growing debate about the value of SD in the osteopathic profession, there is a need to investigate the preferences of expert osteopaths in the clinical application of palpatory findings.We hypothesize that a better knowledge of attitudes and preferences concerning palpatory findings application in clinical osteopathic practice could clarify to the research and practice community the effective application of SD in the osteopathic clinical setting and may represent a starting point to develop a common framework for manual assessment in musculoskeletal manipulations. Indeed, a recent call is launched for qualitative research on the attitudes and beliefs of osteopaths regarding the role of SD in clinical practice .For these reasons, this qualitative study aims to explore the experienced osteopaths' attitudes concerning SD and its role in osteopathic practice.A qualitative examination of experienced osteopaths’ perspectives could improve the interpretative model on the use of SD. Considering the value of the practitioners’ experience would help structure a common framework for the palpatory findings used in manual therapies. Indeed, qualitative research evidence has great significance for evidence-based, person-centered treatment . QualitaAccording to the implications for conducting a qualitative descriptive study , 35 the Data were collected through semi-structured interviews developed through a consensus statement between two researchers  –36. QuesThe authors selected a purposeful sampling to identify information-rich cases relating to the phenomenon of interest . MoreoveTwenty expert osteopaths  were purInclusion criteria were: expert osteopaths who had at least 10,000 h of clinical and academic practice , 46. ParTo achieve a highly specific combination of participants for the study aim, with exhaustive knowledge on the updated models and theories concerning SD, potential participants who did not show experience in the academic or research field were excluded. The size of the study group was dependent on the saturation of the collected data , 37.A single semi-structured interview was conducted with each study participant, who was engaged by the investigators in an inductive, in-depth, recursive, and deep plowing conversation to better express their clinical experience regarding SD , 36, 37.Such technologies mimic the characteristics of face-to-face interviews  while also offering distinct benefits, challenges, and considerations such as ease, simplicity, and user-friendliness . MoreoveEach meeting was audio recorded in order to allow transcription and data analysis , 37, 39.The interviews were carried out between February and April 2021 by the principal researcher (L.A.). In the same period verbatim transcription, re-reading of the texts, and the first idealization of the categories were carried out by the author of the interviews (L.A.) and another osteopath expert in qualitative research (C.L.). The interview transcriptions were emailed to each interviewee, who was given the opportunity to check, correct, or edit the text , 36, 37.Thematic analysis as an independent qualitative descriptive approach is mainly described as “a method for identifying, analyzing and reporting patterns (themes) within data” , 35. TheTwenty experienced osteopaths were contacted by email, eighteen responded to the first email, showing interest in participating in the study. Seven out of eighteen dropped out from the interview for work reasons; eleven experienced osteopaths participated in the study. Demographic characteristics showed in general heterogeneity of the study group Table .Table 1DData saturation was reached by the ninth participant and was confirmed with a further two interviews Table  52]. In. In52]. SD as a safe tissue-touch based communication tool between operator and person complex adaptive health system;The treatment of SD needs to be shared within the healthcare team and the patients with the aim of improving their body awareness;The development of the SD concept in research and practice to better clarify osteopathic profession identity.From the thematic analysis of the interviews, three main themes emerged:Theme 1: SD as a safe tissue-touch based communication tool between operator and person complex adaptive health system [see Additional file The mentioned themes compose an overarching theme representing participants' uses for SD as a part of the person-centered osteopathic approach. Figure SDs impact on the subject's adaptability…then it can cause symptoms at that point. (P1)In general, all participants reported integrating SD into the overall assessment of the patient. SD, in this case, is used as one of the elements to interpret the person's needs without being the main focus of the osteopathic rationale (in which the whole person is at the center). The SD is then integrated with other elements such as adaptive capability and allostatic load (AL) index, expression of daily functions of the patient, sensations, and perceptions of the patient, and progression of symptoms.SD can be somehow parameterized or otherwise quantified through parameters defined by the TART acronym. (P4).I only take SD into account if clinically reflects the expression of an altered functioning of the patient, otherwise it is negligible … it must always be placed in a context of globality. (P4).The parameter that osteopaths objectively use the most is mobility and movement especially in the first degrees. (P6).Participants (55%) referred to the palpable clinical signs of tissue texture alteration, positional asymmetry, altered range of motion, tenderness, classically indicated by the TART acronym ; Some participants considered movement as the main parameter . In order to deepen the analysis of the SD and to understand its relationships with the other parts of the body, some participants declared to rely on specific tests of palpation and relation between structure and function . The palpatory findings highlighted in the first assessment phase should be integrated into person-centered clinical reasoning before having values in the shared decision-making and treatment process. Supposing the SD under examination does not evoke any patient perception and responsiveness in terms of improving body functions, familiar symptoms, or daily movement; in that case, it would be re-assessed and eventually considered during the progression of osteopathic treatment .The best technique for a specific SD you can feel it in the moment. It can't be categorized. It depends a lot on what you feel under your hands. (P7).In assessment and treatment there is a constant exchange of information between the hands and the body that tells you the type of approach to be applied, the force to be applied and the direction to be taken… the ability to have a continuous dialogue with the tissue then translates into the effectiveness of the treatment. (P11).Participants reported the importance of touch and palpation in both assessment and treatment phases. In particular, they claimed to establish a non-verbal communication based on contact: metaphorically speaking, they refer to establishing a dialogue between the patient's tissues, the practitioner's hands, and the patient itself. Such a participatory approach is based on improving patient body awareness to better understand the patient's needs through an osteopath-patient dyadic mutual influence .In my assessment of the patient first there is the history and differential diagnosis, then I integrate the SD… they remain well separated moments for the patient's safety. (P3)During anamnesis collection, the main objective of the visit was to detect possible contraindications for patient safety and therefore to understand if the condition was of their competencies (P1-P11).In general there can be a relationship between the presence of SD and the health of the patient…. sometimes SD does not only cause specific symptoms in the dysfunctional area, but creates an effect on the whole person: from a psychological point of view, of energy, but also alterations on other functions such as digestive, respiratory and cardiovascular. (P11)Today we don't have evidence to demonstrate this kind of  relationship. Clinical practice relies a lot on that, but we don't have the evidence to prove it. (P5)According to the clinical experience of osteopaths, there is a link between patient health processes and the presence of SD (P1-P11). Participants reported that SD is a potential index of AL for the patient. They also consider the related cumulative effects as contributing factors affecting the patient's ability to adapt to environmental challenges . However, some participants specified that it was impossible to prove with certainty and rigor the influence of DS on the patient's health due to the poor research in this emergent field .The SD represents topographically in the patient the point from which I have to start and input … so the SD represents a gateway to the complexity of the patient. (P3)Theme 2: The treatment of SD needs to be shared within the healthcare team and the patients with the aim of improving their body awareness [see Additional file Participants showed heterogeneity in the management of clinical uncertainty. It has been reported that SD was used as a simplifying tool for decision-making ; theoretical models such as the biopsychosocial model , and to complexity medicine framework   were among the proposed strategies. Morevorer, an inductive clinical-diagnostic process, where experience, palpation, and treatment developments lead to an understanding of the complexity of the person emerged .Analysis of the interviews revealed the importance of person-centered treatment, which aims to promote the patient's health. Moreover, participants reported the importance of making the patient active and participating, through sharing the therapeutic approach and using enactive strategies to improve body awareness."It is necessary to make the patients understand that something is changing by looking at his daily life habits: how he walks, how he stands, how he washes, how he dresses, how his work is going or how better he can work."As it was reported by P5 the patients are involved to improve their agency: The aim is always to go in a direction of salutogenesis … my work always depends on the person and the clinical moment. (P10)According to the participants, the therapeutic aim of OMT is to ensure the improvement of the patient's health status and adaptive capacity . If SD shows a marked influence on the patient's functions and presentation, it would be a key point for the treatment; on the contrary, it would take less importance and wouldn’t be part of the treatment . The treatment is therefore structured around the person at the time of the consultation .For the patient this thing of the concordance between a perceived symptom and an area possibly involved with the perception of the symptom and the cessation of the symptom as a result of a technique, may have a certain kind of influence from a placebo point of view … the patient becomes aware of a present relationship between an area of the body, his\her possible symptom and the cessation of the pain sensation, which could the patient to have a different perception of his body and a different identification of his main symptom. (P1)Particular emphasis was placed on improving patient body awareness; not only possible through the specific effects of OMT, but also through enactive clinical strategies. This would not only increase engagement with the patient but could also play a useful placebo role in the success of the treatment .When I have to explain to the patient the concept of SD, I use my usual classical metaphors … then I explain that the osteopath assesses structure\function and treats to restore functions of the musculoskeletal, nervous, immune and endocrine systems. (P6)Different communication strategies emerged to explain the SD concept to the patient. The use metaphors, which have been transmitted over time by exponents of osteopathic practice ; A more immediate language, related to the patient's feelings, in order to create a direct bridge between the theoretical definition of SD and the patient's perception of it .Medical specialists and other health professionals do their own examinations and detect altered function parameters that we could call SD as osteopaths, but then many times they don't know how to interpret what they find, so they identify me as the interpreter of the objective finding. What they want to know is why this thing is not functioning well and what is not working as it should. (P9)Theme 3: The development of the SD concept in research and practice to better clarify osteopathic profession identity [see Additional file According to participants, SD could be used as an interface of dialogue with other health professionals, in order to understand and define the positioning of osteopathy in the patient's care environment . Furthermore, one of the main competencies of the osteopath represents the expert able to analyze, understand, integrate and treat the functional alterations of the patient in order to improve the body awareness and the health status of the person .Osteopaths consider SD as one of the milestones of the osteopathic profession. SD is a fundamental element in the osteopathic health adaptive approach to the person, as osteopaths consider SD as related to AL sources, such as body functions impairments. However, participants also reported the need to expand our knowledge of SD.“It's now time for us to proceed along this scientific research road and we should go towards scientificity to be better recognised by the healthcare system".In this regard, P7 claimed that SD is an alteration of the body structure, not only articular but also fascial and all related functions. It has an adaptive function to try to find the best possible conditions locally to allow the person to live his or her daily life. (P6)Participants expressed different views on the theoretical definition of SD describing it as a communicative key point between the practitioner and the patient or referring to the definition drafted in the glossary of osteopathic terminology . Anyway, there is an emergent mindline in considering SD as a local adaptation syndrome .I integrate and treat SD in my treatment because I am an osteopath! (P3)SD is a good working tool for osteopaths. Although not much is actually known about SD and research on it should be improved. (P10)Participants reported that SD is one of the specific elements that characterize the osteopathic identity and differentiates it from other health professions . All participants stated that they consider SD as a fundamental part of their osteopathic education and clinical experience (P1-P11). Moreover, they pointed out that although SD is an important element for osteopathy, the community of practice is still debating about its usefulness in contemporary clinical practice .We don't really know all the pathophysiological mechanisms behind SD, and we don't yet have a fully effective reference model … we don't know exactly how SD works and there is a need for research in this direction. (P6)Participants reported the absolute importance of increasing their knowledge about SD characteristics and pathophysiological mechanisms . The confusion on SD among the osteopathic clinical environment is also caused by the absence of well-structured scientific evidence .I am not worried about the lack of intra-operator and inter-operator reliability. If the SD becomes an entity to interact with the system-patient, the SD would acquire a typically subjective value. Subjective from the point of view of the operator, the patient and the new entity (operator-patient relationship) that is created. (P3)Another key topic of discussion on scientific research was inter and intra-rater reliability. Participants expressed the need to improve reliability values through standardized palpatory training validated by research and using patient perceptual feedback. This would make the osteopath's palpatory findings possibly more reliable and in agreement with contemporary clinical practice requirements . However, it has been emphasized that SD is an ontologically subjective finding which characterizes the personal aspect of osteopathic treatment .The present qualitative study investigated the attitudes and preferences about the use of SD in osteopathic patient care. The main conceptual framework of the study allows the researchers to evaluate narrative resources of life experiences and to present constructivist perspective in themes to describe pre-given essences and structures of experienced osteopaths. It explores the lived experiences of clinical role and relevance of SD. Despite the debate within the profession highlighting critical points regarding the validity of the concept of SD , 24, 28,The following paragraph will discuss the most significant findings following the three main themes that arose from data analysis Fig. .Fig. 3SoAssessment of contraindications to osteopathic treatment to ensure patient safety; confirming the findings of another qualitative study . HoweverSDs assessment and their relationships with the patient's functional alterations through palpatory tests. This phase, in which the practitioner operates palpation and passive/active movements to perform provocation-inhibition tests –57, is cIdentification of the SD’s relevance for the patient's presentation and needs. This is partially conferred by the severity of the SD  but is effectively validated by the link between SD-functional alterations and patient feedback. In other terms, it is evaluated in a shared decision-making process if a specific type of touch, executed in a particular area, can evoke perceived changes in patient agency, in the ability to perform daily movements, or perform a specific objective examination test. During the assessment of SD, an area of interest for both patient and osteopath, practitioners investigate patients' body awareness to better understand their psychological perceptions in exploratory verbal and non-verbal communication . OMT appThe first theme emerging from the data analysis has highlighted participants' idea of SD as a safe tissue-touch based communication tool between operator and person complex adaptive health system. Participants refer to SD as an outcome of a touch-based participative interactive process between osteopath and patient, also shared by verbal communication respectful of the patients' expectations. The respondents' attitudes are to consider SD as an emergent pattern of body framework and systems interdependence that informs the sense-making of the different complexity domains of the daily clinical scenarios . FurtherThe mentioned approach is not dissimilar from the most widely utilized method to justify a treatment application site used by chiropractors: i.e., Pain, Asymmetry, relative Range of motion, changes in Tissue temperature/texture/tone, and findings from Special tests (PARTS) . These cThe putative model for the selection of personalized osteopathic approaches , 60 can Finally, experienced osteopaths reported using empathic verbal communication with non-verbal interaction and proximity approaches based on touching body regions of interest for patients and osteopaths, such as SD , 60. In The second theme emergent from experienced osteopaths' perspectives describe that the treatment of SD needs to be shared within the healthcare team and the patients with the aim of improving their body awareness. According to the participants’ perspective, SD results in a potentially helpful concept for sharing the object of the osteopathic person-centered intervention with mainstream healthcare professionals. Thanks to the description given by the International Classification of Diseases  , SD is iThe third theme emphasizes the need to develop the concept of SD in research and practice to better clarify the osteopathic professional identity. Concerning the role of SD for the osteopathic profession, expert osteopaths in this study considered SD as one of the few main points that characterize osteopathy, representing the evolution from a traditional concept to a renovated model informed by current knowledge. As discussed previously, participants clearly departed from the purely mechanistic and simplistic conception of SD, emphasizing the centrality of the person's perceptions in the entire clinical process. These results mark the holistic nature of the osteopathic approach, but at the same time requires a deeper understanding of the relationship between SD and the patient's health processes. These present study's findings are in line with the vision reported in a recently published professional commentary  and a naParticipants consider SD as a gateway to the complexity of the patient . A neuroThe finding of the present study could inform the stakeholders involved in the updating process for the glossary of osteopathic terminology , and in In conclusion, this study reflects the common thought of professionals that in order to support the establishment and development of the osteopathic profession within the healthcare environment, it is necessary to corroborate all that specifically characterizes it. For this reason, it will be necessary to reinforce the concept of SD by building a solid shared framework validated by evidence.To obtain a broader view of the phenomenon, further studies should be conducted to explore osteopathic physicians’ perspectives on the effectiveness construct and evaluate the extent to which their views are consistent or in conflict with those of the patients. The present qualitative study aimed to better clarify practitioners’ attitudes and beliefs toward manual assessment and palpatory findings, firstly in the osteopathic field. Nowadays there are available data to start updating the concept of somatic dysfunction and unravel what part of the community of practice is perceived as an enigmatic role or influence of the SD in osteopathic practice , 28. HowTo the best of our knowledge, the present thematic analysis is one of the few qualitative studies conducted on the topic. We acknowledge some limitations, first the study was carried out only on Italian osteopaths. Moreover, only one of the participants was female , 82, 83.Furthermore, despite the research team underwent a self-reflection activity to express their own personal beliefs prior to the data analysis, we cannot exclude that, especially where researchers had the same prior opinion on a specific topic, self-confirmation biases might have occurred in the interpretation of the interviews .A panel of expert Italian osteopaths consider the concept of SD as a valuable tool integrated into the osteopathic evaluation and treatment process. The shared concept and clinical application of SD is informed by person-centered care concepts and from the fields of neuroscience, cognitive and complexity science. Our study reports a common need among osteopaths to develop an evidence-based framework of SD to allow the best development of the osteopathic profession. Moreover, this study could help the scientific community in developing a uniform framework for the use of palpatory findings in manual therapies.Additional file 1: Semi-structured interviewAdditional file 2: The most relevant participants’ quotes


Digital holography is an effective technology in image reconstruction as amplitude and phase information of cells can be acquired without any staining. In this paper, we propose a holographic technique with an improved Gerchberg-Saxton (GS) algorithm to reconstruct cell imaging based on phase reconstruction information. Comparative experiments are conducted on four specific models to investigate the effectiveness of the proposed method. The morphological parameters  of abnormal erythrocytes can be obtained by reconstructing cell hologram of urinary sediment. Notably, abnormal red blood cells can also be detected in mussy circumstances by the proposed method, owing to the significantly biophysical contrast (refractive index distribution and mass density) between two different cells. Therefore, this proposed method has a broad application prospect in cell image reconstruction and cell dynamic detection. In the research field of biomedical and life sciences, researchers expect to capture the cell morphological shapes, dynamic characteristics, physiological parameters, interaction among cells, cell reactions to medicines and drug transport information by visual observation of biological cells in nutrient solution or under natural circumstances, which has an important role in early diagnosis and medicine design . OpticalOptical holography is a technology that adopts a photosensitive medium to record the optical wavefront information and that subsequently superimposes a second wavefront, which is referred to as a diffracted wave, to reconstruct the final image . DigitalIn this paper, we proposed a holographic technique to reconstruct cell imaging based on phase recovery information using an improved GS algorithm. The improved GS algorithm could optimize the initial phase based on local convergence theorem, and accomplish the reconstructed holographic image from contrapuntal phase information. We built four specific models to investigate the effectiveness of the proposed method. Comparative experiment results demonstrated that the proposed method is able to reconstruct phase images with a high signal-to-noise ratio, in which the edge and whole structural information has been reserved. The proposed method is utilized to detect abnormal red blood cells in urine sediment. Specifically, the improved GS algorithm enhances the quality of the phase-reconstructed holographic cell image and successfully detects abnormal red blood cells with distinct edges from the mussy circumstance. This method has great potential for practical biomedical applications in monitoring cell activities.via the beamsplitter cube, and the laser beams are expanded by a beam expander. The outgoing beams from the beam expander are then collimated by a convex lens, and the beams are regarded as plane waves. One incident plane wave is projected onto the sample object, and the other plane wave goes through the acoustic-optic modulator as the reference wave. The frequency of outgoing waves from the acoustic-optic modulator has changed. Then, the light wave projected by the sample object and reference wave transmit through different optical paths and then become incident on the CCD sensor, on which optical interference simultaneously occurs. The CCD sensor acquires the holographic data, which are saved by the computer. The digital holographic technique eliminates the laser source and complex light path structure with respect to optical holography. The digital holographic technique saves the interference pattern generated on the conventional sensor plane of optical holography as a digital image for simulation  is employed as an indicator to assess the results. The indicator of the RMSE is expressed as follows:.In this study, the original image was a coloured image of urine sediment with 493 The GS algorithm with a random initial phase was conducted on the preprocessed greyscale image to investigate the performance of cell holographic imaging. The phase reconstruction-based cell holographic images for Model 2 are shown in We conducted holographic imaging using an improved GS algorithm with an optimal initial phase to investigate the effectiveness of the proposed method for cell holographic imaging. The root mean squared error (RMSE) was calculated to quantitatively demonstrate the impact of phase reconstruction. We take the logarithm of the RMSE for easy comparison. The RMSE results support the above conclusion that the proposed method is suitable for cell holographic reconstruction.Model 2 is the unmapped phase original GS algorithm; the phase peaks are disordered and small. Model 3 is the phase of the mapped original GS algorithm; the phase peak at the red blood cell in the target image is more obvious than that in Model 2. Model 4 is the phase of the mapped improved GS algorithm. Compared with Model 3, the phase peak at the position of the red blood cell is slightly higher, and the performance of the phase imaging image quality is slightly outstanding. Each model ultimately presents a phase energy diagram with 20, 200 and 2,000 iterations.To verify the enhancement effects of the improved GS algorithm, the phase distributions of different models were conducted using corresponding methods with different iterations, as shown in In this paper, we proposed an improved GS algorithm for cell reconstructed imaging, which demonstrated the capability of detecting normal red blood cells in urinary mussy circumstances. The proposed method adopted phase mapping and optimization to overcome the random and chaotic defects during conventional phase reconstruction processing.The holographic image based on amplitude reconstruction results demonstrated that cell edges and detailed information is difficult to extract from the amplitude information. The comparative experimental results suggested that phase information was more important for cell holographic imaging than amplitude information. The amplitude information only demonstrates the light and shade distribution of the image, but does not associate with the content of cell characteristic properties, while the phase information is related to cell characteristic properties, such as edge and structure. According to the results of Model 3 and Model 4, when the phase was mapped in the range of Cells can be considered phase objects. As many cells have a low absorption or scattering rate of light, cell phase changes are closely associated with the structure and other morphological parameters. Therefore, digital holography has attracted more attention in the field of biological cell imaging as it is capable of quantitatively analysing biological cells and non-destructively and dynamically observing living cells. Specifically, In this paper, digital holographic technique could analyse cell physiological property without staining and dyeing, which is more suitable for the reconstruction of cell phase information, and makes up for the shortage that the traditional optical microscope can only provide amplitude images but is difficult to accurately distinguish the cell edges. An improved Gerchberg-Saxton algorithm was adopted to reconstruct the cell holographic image in light of the phase reconstruction information. Comparative experiments were carried out on four specific models with different phase constraint contidions, and the cell holographic image results clearly verified and revealed that this proposed improved GS method achieved better performance than the conventional GS method on the basis of phase reconstruction data. As the phase image reveals not only the spatial information but also the temporal statistics during the transmission of various frequency waves, the accumulation of phase information is able to depict the accurate shape parameters of the recorded object. Then, validation experiments were conducted on urine sediment images, and the reconstructed holographic image results demonstrated that this improved GS method was able to extract abnormal red blood cells with sharp edges and filter out other impure objects. In conclusion, the reconstructed holographic phase image achieved by the proposed method had a high signal-to-noise ratio, and the method was specific to discriminate the morphological parameters. Thus, these results demonstrated the possibility of this proposed holographic method in practical biomedical applications in cell activities monitoring.