This paper proposes a novel structural damage quantification approach using a sparse regularization based electromechanical impedance (EMI) technique. Minor structural damage in plate structures by using the measurement of only a single surface bonded lead zirconate titanate piezoelectric (PZT) transducer was quantified. To overcome the limitations of using model-based EMI based methods in damage detection of complex or relatively large-scale structures, a three-dimensional finite element model for simulating the PZT–structure interaction is developed and calibrated with experimental results. Based on the sensitivities of the resonance frequency shifts of the impedance responses with respect to the physical parameters of plate structures, sparse regularization was applied to conduct the undetermined inverse identification of structural damage. The difference between the measured and analytically obtained impedance responses was calculated and used for identification. In this study, only a limited number of the resonance frequency shifts were obtained from the selected frequency range for damage identification of plate structures with numerous elements. The results demonstrate a better performance than those from the conventional Tikhonov regularization based methods in conducting inverse identification for damage quantification. Experimental studies on an aluminum plate were conducted to investigate the effectiveness and accuracy of the proposed approach. To test the robustness of the proposed approach, the identification results of a plate structure under varying temperature conditions are also presented. Owing to the needs for damage detection of structures, numerous non-destructive evaluation (NDE) based structural health monitoring (SHM) methods have been developed and successfully applied in recent years ,3,4,5,6.EMI methods have been developed to detect the existence of structural damage based on the change in the measured EMI behaviour with PZT transducers. Based on defined damage indicators, EMI based damage detection methods can be generally divided into two different categories: non-model based EMI methods and model based EMI methods.For non-model based EMI methods, the occurrence of structural damage is detected by simply evaluating the difference between measured EMI signatures from the pristine and damaged states of the monitored structure. To quantitatively estimate this difference between the impedance signatures, several statistical damage indicators have been developed. Sun, et al.  presenteTo demonstrate the relationship between the electromechanical impedance response and structural mechanical prosperities, such as stiffness, mass and damping, accurate simulation for the interaction between a PZT transducer and the host structure is necessary. Analytical modelling methods for PZT–structure interactions have been developed ,26,27,28Taking advantage of the accurate finite element modelling, sensitivity analyses have been employed in model based EMI damage identification methods for inverse problems. Rayleigh–Ritz and spectral element modelling methods have been used in the model based EMI methods owning to their high computational efficiency. Instead of evaluating the impedance signatures by non-parametric metrics for damage detection, alternatively, model based EMI methods can be developed to identify the location and severity of structural damages by updating the physical parameters of the numerical model of the host structure with surface bonded PZT transducers based on measured impedance responses. Xu  investigl1 norm regularization technique) based damage identification method has been developed to overcome the abovementioned limitation [l0 norm regularization technique. The multi-objective Dividing RECTangles (DIRECT) algorithm was implemented to solve the multi-objective optimization problem. The admittance (inverse of impedance) of 21 frequency points around two impedance resonant peaks were used to update the finite element model and identify the potential structural damage in 25 segments of an aluminum beam. Fan, et al. [1l norm regularization technique. Experimental studies on beam structures were conducted to validate the accuracy of using the developed method to identify the location and severity of structural damage, with only a limited number of resonant frequencies in impedance responses . Conducting the modeling to simulate the PZT–structure interaction in large scale structures is challenging, e.g., for plate structures, since a very fine mesh is required for structural modeling to obtain accurate impedance responses in a very high frequency range. Therefore, a very large number of elements will be observed for a large size structural model. This brings significant difficulty for model based structural damage identification, since the number of unknown parameters will become much larger than that of the available measurements. However, the available and effective features from impedance response data are limited. To the best of authors’ knowledge, the sparse regularization based EMI technique has not been extended to structural damage quantification in plate like structures.On the other hand, using the conventional Tikhonov regularization method to solve the ill-conditioned inverse problem for damage localization and identification is limited by the major drawback that the solution tends to be overly smooth . In termmitation ,42. Cao,mitation  develope, et al.  developeFor current non-model based EMI methods, the main limitation is the difficulty to quantify and locate structure damage. Even though model-based EMI techniques have been carried out to overcome this drawback, most of the previous experimental studies of such method were carried out on the simple beam structures.In this paper, a new EMI based structural damage quantification approach, using model updating with impedance sensitivity and the sparse regularization technique, is developed. Based on the modelling method shown in the previous work, the proposed sparse regularization based damage identification method is extended to the plate structure, which has been rarely studied with the EMI technique. The sensitivity of resonance frequency shifts in impedance behaviors with respect to structural stiffness parameters are used to update the finite element model of the host structure and identify the stiffness reductions in the host structure that are related with structural damage. Experimental studies on an aluminum plate with a surface bonded PZT transducer are conducted to validate the accuracy and performance of the proposed approach for structural damage quantification in relatively large structures, e.g., plates. The sparse regularization technique is applied to achieve accurate identification results for the host structure with numerous segments, but using a limited amount of measured impedance resonance frequency shifts. Compared with the study on a beam structure , the numIn this study, the finite element model of simulating PZT-structure interaction is developed by using COMSOL Multiphysics 5.2. Piezoelectric analysis is considered as the multi-physics field analysis, which describes the coupling effect between the mechanical and electric properties of piezo-material. Based on the combination of the linear constitution relationship of electromechanical coupling effect by Yang, et al. , the couOne of the most commonly used damping models in previous studies is the Rayleigh damping model, which can be expressed asBy using the first two orders of structural modes, the exact value of the damping coefficients can be calculated. In Equation (4),  as zero , and theOwing to a wide frequency range of the excitation used in the EMI based SHM techniques, a finite element model using a weaker frequency dependent damping model, namely, the hysteretic damping model, has been developed by Lim and Soh .The conventional Rayleigh damping model shows a non-negligible limitation in simulating impedance responses for the large and high frequency range. Since For a harmonic motion, With the variable stiffness multiplier and frequency independent damping ratio, the hysteretic damping model is capable of avoiding the overdamping problem for the modes that have natural frequencies larger than  studies ,45, initModel based EMI methods for damage identification have been investigated. The most commonly used measurements for model updating are the impedance/admittance magnitudes around the resonant peaks in an impedance/admittance curve. However, the difficulty to ensure the high accuracy of the predicted impedance/admittance amplitudes at all the selected frequencies would limit the performance of damage identification with those magnitudes of impedance measurements for model updating. Since the structural damage causes significant frequency shifts at the resonance peaks of impedance responses , using tMany studies on the sensitivity analysis based methods have been carried out for structural damage detection. For damage identification, simulated and measured results are compared and structural damage indicators are estimated by minimizing the difference between them. In general, structural damage can be simulated as stiffness reduction . In thisThe high working frequency used in EMI based methods ensures the sensitivity of using such methods to detect minor changes in host structures. Although the performance of using finite element modelling for the prediction of the high-frequency impedance response has been demonstrated by other researchers ,45, a fijth element of the host structure indicating that the element is intact. When jth element is completely damaged. Assuming that the local structural damage is defined as a change in the structural parameter, i.e., Young’s modulus, the relationship between impedance responses and the structural physical parameters of the host structure can be expressed asThe proposed EMI based damage quantification approach uses the resonance frequency shifts of the measured impedance responses as the targets for updating the numerical model by matching the analytical values calculated from the finite element model to the measured ones through the least squares method asLike most of the inverse problems, Equation (10) is an ill-conditioned problem due to the limited number of impedance measurements, but a large number of system parameters of host structure to be updated. To provide bounds to the solution and stabilize the inverse problem, the damped least-squares (DLS) method is widely used. The DLS solution of Equation (10) can be derived asl2 norm, and the second term provides restraint to the solution. The second term of the right part of Equation (12) is the regularization term for the stabilization of the damped least squares solution Equation (11) can be solved using the conventional Tikhonov regularization method by minimizing the following objective functionTheodoridis, et al.  pointed l1 norm regularization is applied in this study, since the l1 norm regularized optimization is a convex problem which can be solved by more efficient linear programming techniques [l1 norm regularization for structural damage identification with vibration measurements. Then, the inverse problem is solved by minimizing the following equation based on 1l norm regularizationl1 norm. The solution of Equation (15) can be obtained by solving the least absolute shrinkage and selection operator (LASSO) problem, which can be expressed asIn general, only the impedance response in a certain frequency range can be used in the EMI based method owing to the computational demand. Therefore, a very limited number of frequency shifts can be extracted from the impedance measurements in the selected frequency range. According to Park, et al. , multiplg sparse . l1 normchniques ,51. Zhanchniques  used l1 l1 norm regularization term l2 norm regularization term l1 norm regularization is shown in l1 and l2 norm regularization, that are a square and a circle, respectively. The possible solutions are expressed as the blue straight line which is tangent to the restraint region. It is clearly observed that the solution using l1 norm regularization is most likely to be obtained in the corner of the constraint region, which is located on the axle with one of the coordinates equal to zero  and (14) to solve the ill-condition inverse identification problem is the regularization term. The l1 regularization technique was used to solve the ill-conditioned inverse problem which is expressed in Equation (14). It is noted that the sensitivity matrix should be re-calculated in every iteration, when the stiffness parameters are updated. In this study, the convergence criterion is defined asThe flowchart of the proposed approach for structural damage quantification of plate structures by using sparse regularization based impedance technique is demonstrated in Experimental studies on an aluminium plate structure installed with surface bonded PZT transducers have been conducted. Firstly, the baseline impedance responses from the intact host structure were obtained for the calibration of the initial finite element model. The measured impedance responses from the damaged structure were then used for the damage identification using the proposed sparse regularization based structural damage quantification technique. The details of the experimental setup and the damage identification results are presented and discussed.To experimentally validate the accuracy of the built finite element model for the PZT-plate structure interaction and investigate the performance of the proposed damage identification approach, a 300 mm × 300 mm × 4 mm square aluminium plate was used as the testing specimen in this study, as shown in In this study, damage was introduced as a hole created by a hand drill with a diameter of 6 mm. To locate the damage via the proposed approach, the aluminium plate was further divided into 100 square segments. Each square area has a size of 10 mm × 10 mm. In other words, there were 100 unknown parameters of the host structure in the inverse identification. The experimental configuration is shown in To quantify the damage using the sensitivity based model updating with sparse regularization and resonance frequency shifts, the finite element model of the intact aluminium structure with a surface bonded PZT transducer was built. In this study, a three-dimensional finite element model was developed by using COMSOL Multiphysics 5.2, with eight-node solid elements. The cylinder PZT transducer was first modelled in COMSOL Multiphysics 5.2 using the property parameters in accordance with PIC 255, which are provided by the manufacturer, as given in Based on studies by Makkonen, et al. , three tBased on the sensitivity analysis of the resonance frequencies with respect to the system parameters, the most sensitive parameters were selected to be updated. The modified parameters are shown in For finite element modelling, many possible failure modes and damage phenomena can be simulated as changes in the bending stiffness of the elements . In thisedlander . The ideIn this study, the frequency shifts of 28 resonance peaks in the impedance responses between 20 kHz and 30 kHz were selected for damage identification. In the first step, the host structure was divided into 100 square segments of equal size, and the Young’s modulus changes in these segments were identified. The damaged segments were then further divided into nine square segments. The stiffness changes of these sub-segments were calculated in order to acquire the precise location and severity of the structural damage. It should be noted that structural damage is simulated in a different form compared with real experimental tests. Specifically, the Young’s modulus of each segment was used for model updating in the proposed damage identification method, but the actual structural damage was introduced as a drilled hole. It is necessary to estimate the equivalent Young’s modulus change corresponding to the drilled hole in the damaged segment. According to Li, et al. , the damIn this section, experimental tests on the undamaged and damaged plates were conducted and the identification results were obtained to validate the accuracy and effectiveness of the proposed approach. The experimental studies were conducted to locate and quantify the severity of the structural damage in the aluminium plate. The configuration of the host structure and surface-bonded PZT transducer is introduced in A single damage scenario is considered in this section. There were 100 potential damage locations on the thin aluminium plate. In contrast, the identification results of using the proposed approach with sparse regularization, as shown in To further identify the more accurate location and severity of the damage, segment Experimental studies were conducted to evaluate the performance of the proposed method under the effect of environmental uncertainty, i.e., the temperature conditions of the conducted tests and the results of these studies are presented in this section. The investigation focuses on the influence of temperature variation on the impedance signature. Experimental tests were carried out in a normal range of outdoor temperatures. Extreme temperature was not considered in this study.Due to the nature of piezoelectric materials, the electrical property of a piezoelectric transducer is sensitive to variation in environmental conditions, such as temperature and humidity. For a system monitoring an actual outdoor structure, the temperature difference between day and night could lead to non-negligible changes in the impedance responses. Studies have been carried out to quantify the effect of temperature variation on the EMI based SHM technique. Since Park, et al.  investigMost of the existing studies about the compensation methods to counteract the effect of temperature on the impedance signature are based on the non-model based EMI technique using statistical damage indicators, such as RMSD. For the model-based EMI technique, the impact of temperature variation on the performance of damage identification has rarely been studied. However, the changes caused by the environmental uncertainty could lead to significant errors and false predictions. In this study, the changes in the impedance signature caused by varying temperature are investigated. Tests were carried out based on the experimental configuration introduced in the above sections. In the experimental study of damage detection for an aluminium plate, the undamaged and damaged specimens were placed in the laboratory at 23.5 °C, as a normal daytime temperature. The temperature was measured both with a thermometer and the temperature module on the EVAL-AD5933 impedance analyser board. This state is considered as the reference state of measurement. Then, the specimens were placed in an outdoor condition at night-time at a temperature of 15 °C. To test the tolerance of the proposed approach for damage quantification, the finite element model was calibrated using the experimental results obtained from the laboratory temperature condition at 23.5 °C. Then, the damaged specimen was placed in the outdoor environment. The identification results are based on the impedance signature acquired from the damaged specimens at a temperature of 15 °C. The identification results indicate the performance of the proposed approach under varying temperature conditions.With an 8.5 °C difference in temperature, the damage identification results obtained using the proposed approach are shown in This paper proposes structural damage quantification in plate structures with a model based EMI damage identification method. The study on the approach using resonance frequency shifts of impedance responses and the sparse regularization technique  has beenMore studies are needed to improve the performance of the proposed method. A future investigation is warranted to compare different optimization methods for the sparse regularization method, such as Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm, to improve the computational efficiency. Nevertheless, more case studies with different damage types, such as laminated composite plate debonding, should be carried out to demonstrate the applicability of model based EMI technique.


PLOS ONE’s Editorial Board, and identified the following concerns:Following the publication and correction of this article , 2, quesThe individualized homeopathic treatment (IHT) and the decision-making framework for treatment adjustments were not reported in sufficient detail to enable reproducibility of the study or an assessment as to the clinical validity of treatment choices. In response to this issue, the authors provided information in post-publication discussions about the individualized homeopathic consultations and guidance used for homeopathic prescription, and commented that potencies of homeopathic remedies were selected on the basis of homeopathic principles. Citing a 2014 systematic review of clinical trials involving IHT , the aut−60) and 200C (10−400) dilutions—represent placebo effects rather than responses to the homeopathic treatments. The authors disagreed with this point, provided additional information about the methodology, and asserted that elements of the study design accounted for placebo effects.The study design did not include sufficient controls to rule out the possibility that observed effects in the IHT group—which received homeopathic remedies at 30C (10Insufficient information was provided in the article about the methodology by which diagnoses were made in the study, the reliability of that methodology, and how blinding was achieved during the diagnostic assessments. The article reported that participants were diagnosed according to DSM-IV but did not include details as to how the criteria were applied in practice during the trial. The authors provided additional methodological information in post-publication discussions.PLOS ONE Editors and the consulted Academic Editor reviewed the information and additional methodological details provided by authors in response to each of these issues. The Editors determined that the additional information provided did not fully address the above concerns, which call into question the reproducibility of the study, the scientific validity and rigor of the study design, and whether conclusions are adequately supported by the results. For these reasons, the PLOS ONE Editors retract this article. We regret that these issues were not identified and addressed prior to the article’s publication.The During the post-publication assessment, questions were also raised about whether the 6-week duration of the study and fixed dosing regimen for fluoxetine treatment were sufficient to allow an assessment as to the efficacy of fluoxetine where it was prescribed. The consulted Academic Editor noted that other randomized clinical trials using fluoxetine allow for increasing dosage in case of nonresponse. The Academic Editor also noted that per clinical practice guidelines, trials of antidepressants should generally last 8–12 weeks  and it gEdCM-C, LL-G, LA-F, and JA-B did not agree with retraction.


Although inter-ethnic encounters take place in multiple domains of daily life, ethnic intermarriage has typically been studied in relation to places of residence but rarely in relation to workplaces. Focussing on migrants is the most common approach to the study of intermarriage, whereas focussing on native majority population is less frequent. This study investigates an extent to which the share of immigrants at the workplace establishment and in the residential neighbourhood influences the natives’ likelihood of choosing a foreign-born partner. The analysis is based on longitudinal register data that cover all residents of Finland in 1999–2014. We focus on native Finnish women and men born from 1981 to 1995. We estimated a discrete-time event history model with competing risks, distinguishing the first-partnership formation with a foreign-born partner and a native-born partner. The share of immigrants in the residential neighbourhood and workplace both increase the propensity of choosing a foreign-born partner, but the share of immigrants in workplace tends to have a stronger bearing on the partner choice. High exposure to other ethnic groups in one domain is associated with reduced effect of the additional exposure occurring in another domain. The effect of ethnic diversity at workplace tends to be more pronounced among women. The study contributes to the literature by examining both the independent effect of residential and workplace contexts on the formation of ethnically mixed partnership among the native majority population, as well as the interaction between the two. The large inflow of immigrants to Europe over the past decades has put to test the integration capacity of the European societies. Finland has been mainly a site of intra-European migration, but in recent decades the country has been also one of the destinations of migration flows to Europe. Willingness of members of the native majority population to intermarry is often considered as the strongest indicator of immigrant acceptance and immigrant integration in the host society Gordon . For migAlthough opportunities for first-hand inter-ethnic encounters could emerge in multiple domains of daily life, intermarriages have typically been studied in relations to one domain, most often places of residence. For people who work, however, workplaces serve as crucial places of daily interaction and encounter , and how they are influenced by such interactions . The social networks that people have formed both in the current as well as in the past residential and workplace contexts determine to whom they have been exposed to. For example, Rosenbaum et al.  found thThere are competing views on how the share of immigrant population might affect native attitudes towards immigrants at places of residence and work. On the one hand, living or working together with immigrants and getting a first-hand personal experience with ethnically diverse setting might reduce prejudices and increases tolerance towards immigrants . However, in contexts with the highest proportion of immigrants, the willingness to intermarry with migrants will be reduced (Hypothesis 2). We further assume that workplace context is more important than residential context in shaping natives’ willingness to intermarry with migrants because of the more intense daily interaction with co-workers compared to neighbours (Hypothesis 3). We will conduct a separate analysis for the partnering behaviour of Finnish men and women. We expect that residential context is more important for native women (Hypothesis 4) and workplace context is more important for native men (Hypothesis 5) for the formation of mixed ethnic unions with immigrants. Alternatively, it is possible that the expected impact of ethnic concentration disappears after controlling for contextual factors  as well as individual characteristics  (Hypothesis 6). Finally, we are interested in whether the associations between residential and workplace context and inter-ethnic partnering vary across migrant groups. In light of the preference for partners with a similar background discussed earlier in this section, we assume that these associations would be more pronounced for immigrant groups originating from settings that are culturally closer to the host society (Hypothesis 7).Compared to other Nordic countries Finland’s experience as a receiver of international migration is more recent. However, Finland has a historic Swedish minority that forms more than 5% of the total population Nieminen . A signiEthnic minorities and recent immigrants live mainly in the three main urban areas of Finland, as well as in southern and western coastal areas and areas close to Russian border in the east . A minor group of adolescents who had started a partnership before age 18 were excluded.Unlike many studies of ethnic intermarriage, we focus on natives instead of immigrants. We define native Finns as individuals who were born in Finland. In addition, our study population includes return migrants who were born abroad to Finnish-born parent(s) and who had moved back to their parents’ country of birth. Persons who were born in Finland to foreign-born parents (the second generation of immigrants) are also included, but given the relatively recent start of large-scale immigration to Finland, the proportion of the second-generation immigrants is relatively low in the birth cohorts covered.The event of interest is the formation of first partnership. Based on the yearly information about the place of residence (down to the specific dwelling), co-residing conjugal partners are identifiable in the Finnish register data, even when they are unmarried and childless. In this study, we draw on the procedure employed in the register to identify partnerships. We use discrete-time data with yearly intervals; the first observation when the partners are registered in the same address is considered to indicate the beginning of their marital or cohabiting union. One of the limitations of this approach is that it underestimates the prevalence of partnerships. In particular, it misses unions where partners de facto cohabit, but are registered in different addresses. Likewise, cohabiting unions of relatively short duration (less than a year) which are formed and dissolved between two yearly observations are not considered in the analysis. For the purpose of our study, two types of partnerships are distinguished: endogamous partnerships (both partners are native Finns) and exogamous partnership (the partner is migrant). To denote the latter type of unions, we also employ the term inter-ethnic  partnership in the article. In order to account for the heterogeneity of the immigrants who have arrived in Finland, we distinguish between inter-ethnic unions with immigrant partners of Western and non-Western origin in the analysis (the details of the groupings are discussed in the following sections). After all necessary exclusions, our final research data set included 494,040 women and 518,513 men who formed 11,918 and 7501 inter-ethnic partnerships, respectively.We estimated proportional hazards event history models separately for native women and men. The exposure time started at age 18 and ended in the year during which the first partnership was formed. Exposure time was censored in 2014, if a person was never partnered at that time, or earlier, if a person left the country or died. In order to count the fact that union formation risks change in age, we held our baseline hazard (age) constant during the intervals of 2 years, but allowed it to vary between the intervals. For women and men alike, we estimated two sets of competing risk models, for exogamous and endogamous partnerships, respectively. For exogamous unions, additional group-specific models were estimated for partnerships with individuals of Western and non-Western origin.We calculated the share of immigrants in the area of residence. We opted for the share of migrants in age group 18–40 that focuses on the individuals who are most active in the partnership market. The neighbourhoods were defined according to postal service codes . If the zip area was not known for a person, we used the proportion of immigrants in the municipality. To avoid the overestimation of the impact of neighbourhood, we backdated the variables related to place of residence for 1 year.The register data used in the study provided employment information for all individuals who were currently employed, including the encrypted identification numbers of the enterprise and establishment where a person worked. This allowed us to calculate the share of immigrants at the workplace. Unlike for the neighbourhood, no restriction was imposed on the age of the employees because by default the work-related information is limited to working-age population. Individuals who were currently not employed were classified either as ‘studying’ or included in the residual category (‘other/not known’). We also experimented with the backdating, but unlike for neighbourhood the results deemed it unnecessary for our work-related variables.To account for the fact that neighbourhoods and workplaces markedly vary in size, we included respective controls for both domains. The neighbourhood size is a continuous variable indicating the number of residents in the area ; a categorical specification is used for the size of workplace (establishment). In addition, the region of residence  was added to the controls.Individual-level controls included birth cohort, origin, experience of living abroad, mother tongue and educational attainment. The origin distinguishes between persons who were born in Finland to Finnish-born parents and persons who themselves or whose parents were born abroad. Another time-constant variable distinguishes between Finnish-speaking native majority, Swedish-speaking native minority and a small group of native Finns who have an indication of any other language as mother tongue in the register. To account for the influence of international migration, the experience of living abroad considers the episodes during which a person has resided outside Finland. Finally, we also controlled for socio-economic status by using a time-varying information about the highest level of education.Table The initial model (M1.1) includes the ethnic diversity in the residential neighbourhood. The estimates from this model reveal a strong positive association between the share of immigrants in the neighbourhood and the propensity of native Finns to form partnerships with them. Among women, living in areas where the proportion of immigrants ranges from five to nine per cent relates to 77% increase in the likelihood of inter-ethnic union, compared to the reference category (the share of immigrants below five per cent). For men, the effect appears closely similar + 82%). Larger proportions of immigrants further increase the chance of forming an ethnically mixed partnership. In the areas of highest concentration of immigrants, the likelihood that native women and men would start a mixed union exceed the reference category 2.8 and 2.7 times, respectively.%. LargerFurther, a series of control variables were added to the model. This markedly reduced the hazard ratio for ethnic diversity in the neighbourhood (M1.2). For areas with the highest concentration of immigrants, the hazard ratio decreased from 2.88 to 1.45 among women and from 2.66 to 1.37 among men, respectively. However, despite a reduction relative to the initial model, living in an ethnically diverse neighbourhood significantly increases the likelihood of native Finns’ initiating a mixed partnership. A statistically significant increase also persists in areas with a relatively moderate (five to nine per cent) proportion of immigrants. This applies to women and men alike, with no marked gender difference in the effect.A stepwise procedure of adding variables to the model  shows that the statistically significant negative effect does not fade away after the inclusion of controls for the size of residential area, individual characteristics and the region in the models. The opposite gradient of our main independent variable for endogamous and exogamous partnerships suggests that the increase in ethnic diversity in residential neighbourhoods has a potential of advancing the ethnic intermarriage and replacing endogamous unions in part with ethnically mixed partnerships.In order to get an account of the effects on partnership formation of ethnic diversity at work, another set of event history models was estimated Table . In thes3The initial model (M2.1) includes the ethnic diversity at workplace. The estimates from the initial model indicate a significant positive relationship between the share of immigrant co-workers and the propensity of native Finns to enter ethnically mixed unions. For women, having a workplace in which the proportion of immigrants ranges from five to nine per cent of employees is associated with 51% increase in the hazard ratio relative to the reference category (workplaces with less than five per cent of immigrants). Among men, the relationship is closely similar (46% increase in the hazard ratio). Larger proportions of co-workers with immigrant background further add to the likelihood of forming an ethnically mixed partnership in more or less a linear fashion. In case the share exceeds 15%, native women and men in Finland exhibit a 2.5- and 2.3-fold increase in the chances of partnering with a person of non-native background, respectively.The addition of the control variables to the model markedly reduced the hazard ratio for ethnic diversity at workplace (Model M2.1). For workplaces with the highest proportion of immigrants, the hazard ratio decreased from 2.53 to 1.77 among women and from 2.27 to 1.57 among men, respectively. However, notwithstanding the change related to the inclusion of the control variables, Model M2.1 clearly indicates that ethnically diverse workplaces are associated with an elevated likelihood of native Finns’ initiating an exogamous union. A significant increase in the likelihood of inter-ethnic unions also persists for workplaces with a moderate (five to nine per cent) proportion of immigrants.The stepwise addition of the control variables to the model , native men exhibit up to 11% decrease in the rate of entry into endogamous partnerships, associated with the increase in immigrants at workplace. Among women, the reduction in the hazard ratio is only slightly smaller (− 9%). Across models, the hazard ratios for endogamous unions are more stable than those observed for exogamous partnerships. This lends support to the notion that the control variables employed in the analysis are more extensively modulating the formation of the latter kind of partnerships. The opposing gradients found for exogamous and endogamous partnerships suggest that the increase in ethnic diversity at workplaces tends to promote intermarriage between natives and immigrants.In the two previous sections, the role of ethnic diversity in residential neighbourhoods and workplaces was investigated separately. However, the contacts and integration between the natives and immigrants in different life domains do not develop in isolation. To provide insight into how the inter-ethnic encounters occurring in neighbourhoods and workplaces come together, we estimated additional models with ethnic diversity in both domains considered Table .Table 4HThe estimates obtained from the joint model M3) show that the effects of ethnic diversity in residential neighbourhood and workplace are only slightly altered compared to the separate models . In our view, this finding once again underlines the role of individual’s family origin for the partner choice. The effect appears stronger for unions with non-Western partners.Further, the experience of living abroad for some period makes a remarkably strong contribution to the likelihood of exogamous unions. For men, this experience implies a 2.6-fold increase in the likelihood of mixed partnering, and for women the hazard ratio appears slightly smaller. Unlike family background, living abroad exerts a stronger influence on the propensity to form exogamous unions with partners of Western origin. We assume that this is related to the fact that native Finns migrate predominantly to Western countries. However, we are not able to establish the exact causality here. For instance, migration to a foreign country may be itself driven by partnership formation. In addition, experience of living abroad may also involve selection as international migrants do not constitute a random subgroup of the sending population , while workplace context appears more important for men (fifth hypothesis). At odds with our expectation, neither of these hypotheses was supported by the results. The ethnic diversity at workplace was found to have a more pronounced effect on partnering choices among women. Although the difference is not large, it appears to be systematic and cut across all models and levels of the independent variable. We are inclined to relate this result to contextual features: the manifestation of advanced gender equity characteristic of the Nordic-type societies.The consideration of both women and men provided this study with a systematic gender perspective which is not always present in the analyses of inter-ethnic partnership formation. We expected that residential context is more important for native women (sixth hypothesis). This was not the case. Although reduced in magnitude, statistically significant positive effects persisted after the inclusion of individual and contextual controls in the models. Still, a variety of associations between control variables and choice of partner deserve attention. Evidently owing to larger pool of potential partners, the size of neighbourhood was found to make a systematically positive contribution to union formation, with natives and immigrants alike. Across regions, partnering with immigrants appears expectedly most common in Helsinki, followed by other large urban centres, in which inter-ethnic encounters are more frequent than in the rest of the country.A counter-hypothesis anticipated disappearance of the effect of ethnic concentration after controlling for contextual and individual characteristics (seventh hypothesis). This expectation was not supported by the results. The effects of the proportion of immigrants of Western and non-Western origin in the residential neighbourhood were not markedly different.We also investigated whether the associations between the residential and workplace context and inter-ethnic partnering vary according to the type of exogamous partnership. The expectation was that these associations would be more pronounced in the case of partners from regions that are culturally closer to the host society (The study also yielded results that are noteworthy from the methodological point of view. The experience gained underscores the importance of backdating the independent variables that relate to residential context when using discrete-time longitudinal data for the analysis of union formation. According to our results, the failure to do so tends to result in an overestimation of the effect associated with the share of immigrants in residential neighbourhoods. The overestimation arises from the fact that migration is often driven by family formation, a situation termed ‘interrelation of events’ in the literature (Andersson Finally, this study is not without limitations. First, notwithstanding the highly accurate longitudinal data on neighbourhood and workplace context provided the registers, the evidence is wholly lacking on other important elements, especially preferences, which are known to shape individuals’ decisions with regard to partner choice Kalmijn . Second,


Cancer patients have to undergo a difficult medical therapy and are also confronted with various psychological, social and economic problems. Support is available from many providers, but patients often gain no access to it. Accordingly, there is a need for a single point of contact that can provide advice, information and assistance. In the state of Saarland, Germany, a supportive new consulting and information path (PIKKO) for all types of cancer is currently evaluated by the German Cancer Society, the Cancer Society of the Saarland, three statutory health insurances and the Jena University Hospital. PIKKO is designed to improve quality of life, self-efficacy, health literacy and patient satisfaction and to reduce psychological distress, related health care costs and the days of inability to work. This methodical work presents the process and analysis planning of this evaluation.The study population includes all cancer types, both new and existing diseases. PIKKO  is evaluated within a controlled, non-randomized, comparative, multicenter, longitudinal design. In addition to patient surveys, data from statutory health insurances and utilization data from the web database are collected, and interviews with patient navigators and doctors are carried out. Patients are assigned to a control  or an intervention group (u. c. + PIKKO). Primary outcome is the health related quality of life (SF-12) six months after baseline. Secondary outcomes are self-efficacy (GSE), psychological distress such as depression (PHQ-9) or anxiety (GAD-7), health literacy (HLS-EU-Q47) and patient satisfaction in health care . Furthermore, the time course of direct costs of medical care (e.g. work disability days) and usage data of the intervention modules are analyzed. Among other statistical procedures, we use t-tests, univariate tests and growth curve models.If PIKKO proves to be effective, recommendations can be made to health organizations, which should lead to the concept being rolled out throughout Germany and included into oncological guidelines. We expect PIKKO to be a useful addition to usual cancer care, helping to improve the quality of life of cancer patients and reduce healthcare costs.https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00016703This study was retrospectively registered in the German Clinical Trial Register under DRKS00016703 .  The treatment of cancer became more successful in the past decades. Simultaneously cancer incidence is increasing due to an aging and growing population . More anCancer means a major change in the patient’s life and is usually associated with psychosocial distress . In manyOne promising solution for a better and low threshold integration of patient needs is a patient navigation program. In 1990, Dr. Harold Freeman initiated the first patient navigation program in the USA. This early program (and other followers after the Patient Navigator and Chronic Disease Prevention Act passed by the US Congress in 2005) tried to eliminate the barriers to timely care across all segments of the healthcare continuum. A real person, a patient navigator (PN), is the most important part of these programs . UsuallyIn many cases PN are specialized to a single type of cancer e.g. breast cancer or lung cancer . These cTo cover the complex needs of patients regarding navigation in German health care and access to evidence-based and understandable information across all cancer types a comprehensive intervention program was initiated in 2017 in Germany by the German Cancer Society, the Cancer Society of the Saarland, the Jena University Hospital and three statutory health insurance companies . The program is called “Patient information, communication and competence empowerment in oncology (PIKKO)”. PIKKO supplements the usual care with a new consulting and information path.PN have also been tested in other chronic diseases such as diabetes, AIDS, cardiovascular disease, chronic kidney disease or dementia . For sucThe evaluation aims to measure the effect of PIKKO on a patient level , as well as on the level of health care costs which should provide information on the implementation of the care concept and the transfer to other diseases. This paper describes the evaluation concept.PIKKO focuses on communicative aspects and informative needs of cancer patients and consists of four modules. The patients receive 1) the advice of a trained PN and (2) an access to a new database with evidence based information about cancer. Furthermore a fast access to a specialized oncological counseling is guaranteed (3). Finally, a ring folder is provided to patients to cope the paper flood during their illness (4). Within the project the new consulting and information path  is integrated to usual care  particularly the mental component. We expect that patients who underwent PIKKO report a higher HRQoL, less mental impairment such as depression and anxiety, better self-management and higher health literacy than patients of the control group. Furthermore, we expect lower direct health care costs .The design of the evaluation study consists of four components: patient surveys, data provided by statutory health insurance companies, interviews with service providers as well as the usage data of the oncological knowledge database. The non-randomized, controlled, comparative, multicenter, longitudinal design included three groups: experimental group , first control group  and second control group . A non-randomized design with two recruitment periods, starting with the (first) control group, was chosen due to the following reasons: 1) randomization on a test person level was not possible for ethical reasons and for reasons of the statutory basis of the German health care system. 2) It is also not reasonable from a CRM (Customer Relationship Management) perspective to withhold an existing service from needy persons on the part of the statutory health insurances. 3) In a medical facility , intervention and control cannot take place simultaneously to the extent required by this study (control patients could still contact PN). 4) Cluster randomization was not feasible for a project of this size and kind due to the medical infrastructure in the small state of Saarland. Accordingly, the periods were set one after the other and later the participants of the control group have the option to switch to the intervention group. Secondly, to establish the new intervention with all the descripted modules the German Cancer Society, the Cancer Society of the Saarland and the health care insurance companies needed time, nearly one year. However, no time should be lost in terms of data collection, so it was used for the patient survey of the control group. The date of recruitment determines the group assignment. The control group is included in the first project year (while the new intervention is under development) and the intervention group is recruited in the second year (when the new consulting and information path is available). A third group is a random selected sample of patients who are not part of the two other groups. Only health care data are collected for these persons. This second control group allows examining the representativeness of the sample respectively the selection process and the comparisons of treatment courses.To evaluate this health care project, three participating statutory health care insurance companies  work together to offer PIKKO to their insured cancer patients in the Saarland, which is the second smallest state in Germany . About 80 physicians  in about 25 cities (different population sizes) agreed to recruit participants. The intervention is performed by specially trained PN who are located in clinical or outpatient settings.age ≥ 18 years and ≤ 90 years,diagnosis of any cancer disease ),current treatment by doctors from the Saarland,insured with one of the three statutory health insurance companies participating in this study.Patients eligible for PIKKO must comply with all of the following:statutory guardianship,insufficient knowledge of the German language,very strong visual and hearing impairment,dementia or other mental limitations.Patients are not eligible in case of one of the following:Overall, we intend to obtain a heterogeneous sample with various types of cancer, degrees of severity, stages of disease and co-morbidities in order to reflect the reality of everyday care routine including its various aspects as well as possible.To recruit physicians to participate in PIKKO, the consortium leader (IKK Südwest) organized internal (invitations to the IKK Südwest) and participated in external  information events. They are addressed to all physicians of different specialization that are involved in care of cancer patients: oncologists, gynecologists, urologists, general practitioners, internists, and other. The participating hospitals, clinics, and medical practice must sign a study contract to participate in the supply concept PIKKO and to recruit patients. The enrollment is conducted by physicians or trained medical staff e.g. a nurse.For the recruitment of PN, mailings were made to all participating hospitals, clinics and practices. Up to ten persons can be trained with a two weeks course by the German Cancer Society. Target group are people who already work in the field of cancer-related health care such as oncological nurses, social workers or other non-medical staff of an oncological outpatient clinic or oncological department of a hospital.The patients are recruited in various ways. Firstly, they can be addressed directly while attending a medical consultation (outpatient or inpatient) as long as they show the inclusion criteria. The enrollment is carried out directly. Secondly, a landing page at the internet serves as a contact point to patients who hear about PIKKO via mass media such as newspaper articles and radio program or on various events about cancer . The potPIKKO is an additional supportive care intervention with focus on communication and information. It does not replace the usual cancer treatment. Rather, it complements the usual treatment path by integrating four new modules into care.The central module is a PN. Within PIKKO this PN is called (in German) “Onkolotse”. This is a specially trained person with medical background but not a doctor. They attend a two week training course performed by the German Cancer Society, which was exclusively composed for PIKKO. Contents are oncological medical background incl. complementary and alternative medicine, communication, psychological oncology, nutrition and cancer, physical activity and cancer, management of side effects of cancer treatment, palliative medicine, social law, use of the oncological knowledge database, self-management and privacy. The acquired skills, the own experiences, talents and empathy qualify the PN to advise and to accompany participating patients along the complex way through their cancer treatment, especially across sectoral borders of the German healthcare system. The PN also activate the patient access to the oncological knowledge database called “my pikko” (in German “Mein PIKKO”), the second module of the intervention.“Mein PIKKO”  is a webThe third module of the intervention is an offer for all participating patients of a specialized oncological counseling provided by the Cancer Society of the Saarland in order to identify the psychosocial needs of cancer patients. This counseling is arranged by the PN and performed by different course leaders of the Cancer Society of the Saarland. Different offers are available: nutrition course, nutrition advice via telephone, art and creative course, music therapy, Nordic walking, QiGong, yoga, and psycho-social or psychological advices.The forth module of the intervention was also created by the German Cancer Society. It is a ring folder, which is given to all patients at the time of their agreement. With this folder patients can collect and organize all information concerning physician or any other consulting contacts, to keep a personal medication list, to document physical complaints and to collect any discharge letter in a structured way. This folder is not only intended to improve the self-management capabilities of patients, but also to minimize informational deficits in the case of a change of care providers. In this way, patients can find other specialists and hand them over their entire treatment documentation as needed.For any participating physician a hotline of oncologists was established. The hotline is called “onco-expert-phone” and provides the physicians fast and anytime with unbureaucratic help in case of treatment issues.The primary outcome is the health-related quality of life (HRQoL) particularly the mental component score measured by the SF-12 questionnaire , 29 six improvement of self-efficacy measured by the General Self-Efficacy Scale, GSE ,reduction of psychological distress such as depression  or improvement of health literacy measured by the HLS-EU-Q47 , 39,improvement of patient satisfaction in health care measured by the Qualiskope-A ,lower health care costs such as ambulatory and stationary costs, medication costs, costs of psychological therapy,reduction of days of inability to work (DIW).Other measurements and supposed effects by the intervention are:GSE, PHQ-9, GAD-7, HLS-EU-Q47 and Qualiskope-A are well validated , 39, 40.The enrollments of the two allocation groups take place in two consecutive enrollment periods. Every period lasts one year starting with the control group.The patients express interest to participate in the supply concept to the enrollment person who reviews the inclusion and exclusion criteria. Furthermore, the enrollment person informs and educates the patient and hands over the oncological ring folder. After successful enrollment a standardized form is sent to the statutory health insurance company and to the evaluator. This informs the evaluator about the patient assignment and the agreement to establish contact (e.g. by telephone).From this point in timeline there are small differences between the two groups in collecting the baseline data.The evaluation team contacts the patient per telephone and informs the patient about the process of the patient survey (consent to the survey). Then the written baseline questionnaire will be sent to the patient. The patient returns the completed questionnaire postage free to the evaluator.In the intervention group it has to be ensured that the baseline survey is carried out before the intervention starts. Due to the lack of time, the baseline questionnaire is issued directly by the PN. Before the patient and the PN start with the consultation the patient fills out the written baseline questionnaire (rated as consent to the survey). The consultation starts after the handing over of the baseline questionnaire to the PN. In addition to various consulting content and during the first consultation the PN unlocks the patient access to “Mein PIKKO” and offers the specialized oncological counseling. Later the PN returns the patient-filled questionnaire postage free to the evaluator.In both groups the dates of the following questionnaires are computed dependent on the filling date of baseline, which is gathered directly after inclusion (T0). The patients are contacted to fill out questionnaires three (T1), six (T2), nine (T3) and twelve months (T4) after baseline, unless the patient withdraws the consent or dies, or changed from control to intervention group.Baseline, main outcome and every follow-up survey consist of a set of questionnaires  is 6.532%. Thus, the study population included (rounded up) 22,000 patients.The financing of the PIKKO supply concept was calculated for a maximum of 1.800 patients per group, 3.600 patients in total. That means that 1.800 participants of the intervention group can benefit from the PN and the other intervention modules.N = 1014 = 676 + 338 patients (per group 507 = 338 reaching the end point + 169 dropout). The expected dropout rate was 33.3% regarding the baseline (338 of 1014) or respectively 50% regarding the patients reached the endpoint (338 of 676).To evaluate the PIKKO intervention only 676 participants (338 per group) of the patient questionnaires are required to the statistical analyses. This number of cases was calculated with the program GPower version 3.1.7 . The calAccording to the four aspects of this evaluation, four different kinds of data are obtained from four different sources.Up to five times the patients will be asked to fill out a set of questionnaires. The length of these sets varies between 12 and 20 DINA4-pages. With the length and the allocation, the content of the set differs too . The database keeps track the patients’ timeline and allows intervening if the time interval between the patient questionnaires becomes too large . In addition, the database enables the cooperation partners to be kept up to date in terms of recruitment and study process (reports and summaries). Access is multiple times secured for privacy reasons.The filled-out questionnaires are scanned with a standard hardware (Fujitsu fi-7140) and analyzed with FORMS Desktop (Lexmark Enterprise Software) which is software to automatic data entry. This procedure allows a fast and accurate data entry. All marks in checkboxes are transferred with a security of 100%. Numeric and alphabetical characters are verified by the study assistant. During the period of data entry, permanent controls and plausibility checks are performed by the data manager.All electronic data is located in a secure folder on a secure intranet. Only members of the evaluation team get access. The organization database is restricted by passwords. Electronic data is protected against loss by a security procedure of the Jena University Hospital.According to the German laws regarding clinical studies the paper questionnaires will be kept for 10 years in a safe archive of the Jena University Hospital.Characteristics of control and intervention groups  will be analyzed with descriptive statistics. Since no randomization is made for ethical and research practical reasons, univariate tests are used to determine which of the above mentioned characteristics differ between the two groups. Ideally there are no significant differences between the two groups. In the case of significant differences we will compute propensity scores using the corresponding pre-treatment variables. Then, we will apply in the subsequent analyses propensity scores as stabilized regression weights to reduce bias caused by different group characteristics.The main hypothesis of an intervention effect on psychological and physical health, self-efficacy, health care costs etc. will be proofed by the comparison of averages of intervention and control group (resp. t-tests). To estimate the corresponding regression adjusted group means we will use growth curve models. Furthermore, we will conduct subgroup analyses to identify conditional treatment effects.For dropout analysis we will conduct a logistic regression with dropout as criterion and group assignment and baseline variables as predictors applying the regression weight mentioned above. For the time-to-event analysis we will conduct a Cox regression.The level of significance will be α = 0.05. To validate our analyses, we will conduct the analyses with imputed missing data and without imputation.We expect the occurrence of missing values due to dropout or not completely filled in questionnaires. For imputation of missing data we will use a nonparametric approach by random forest imputation respectively the R package missForest , 45. TheThe numbers of enrolled patients and other organizational data are monitored and sent weekly to the consortium leader (IKK Südwest). The study progress is reported quarterly according to an approved milestone plan. All events, progress data, milestones and failures are reported annually to the sponsor. The PN are supervised quarterly by the Cancer Society of the Saarland.PIKKO is a supportive care element without invasive impact on the patients.So far, there is no other project in Germany that offers cancer patients such a wide range of possibilities as PIKKO. There is also no known international study that combines PN, technical applications and course offerings. There are many technical applications, from websites  to apps This new supportive care concept is intended to establish an offer for all cancer patients. Low barriers for the procurement of information such as the website, which offers both specific and general information, are just as much a part of the concept as the broad further training of PN, who can thus advise all cancer patients.The study is designed to evaluate the effect of PIKKO interventions under naturalistic conditions. The according heterogeneity of the sample  tries to reflect the reality of oncological care. Due to the heterogeneity of the sample, subgroup analyses are planned to show which module of PIKKO works best for whom.Furthermore, the longitudinal design with five measurement points allows the investigation of long-term effects.Last, the telephone interviews with participating PN and physicians can show experiences in the implementation that help to make PIKKO a common part of cancer care.In general, less burdened patients, patients with a stronger self-motivation, patients with higher self-efficacy or patients with more social support could preferably participate, leading to a selection bias. Related with this bias can be an overestimation of treatment effects when the treatment is especially effective for less burdened patients. Also an underestimation of the mortality or patient’s withdrawal is possible. To examine the selection bias, we included a second control group which is a random sample of eligible patients based on health insurance company data. We expect that the selection bias is small so that the generalizability of study results should be high.The voluntary and selective participation of hospitals , clinics and practices could lead to a selective clientele of patient e.g. disproportionately many breast cancer patients. However, this could also make the study more comparable to the many studies that have been pre-determined for certain groups, e.g. specialized in breast cancer patients .Due to ethical and other reasons  the design is not randomized. To compensate for this limitation, we will use propensity scores for analyses , 59.Since we will collect questionnaires from seriously ill and elderly patients, we might expect incomplete questionnaires. Missing items and missing complete questionnaires should be compensated by imputation of missing data , 45.Each participant agrees with the use of his data from the statutory health insurance companies. These data are collected from all included patients without their direct participation. However, to collect questionnaire data, we rely on the direct support of the patients. The number of data sets can therefore vary between data from the questionnaires and from the statutory health insurance companies.The study protocol was approved by the ethics committee of medical association of the Saarland at 2nd November 2017. The first patient of the control group was included on 23th November 2017. The control group was recruited till 31st October 2018. Since then till 31st March 2020 the intervention group was recruited. An extension of the recruitment period of the intervention group  was necessary due to the entry of a further statutory health insurance  in the summer of 2019.


The quality of detected lane lines has a great influence on the driving decisions of unmanned vehicles. However, during the process of unmanned vehicle driving, the changes in the driving scene cause much trouble for lane detection algorithms. The unclear and occluded lane lines cannot be clearly detected by most existing lane detection models in many complex driving scenes, such as crowded scene, poor light condition, etc. In view of this, we propose a robust lane detection model using vertical spatial features and contextual driving information in complex driving scenes. The more effective use of contextual information and vertical spatial features enables the proposed model more robust detect unclear and occluded lane lines by two designed blocks: feature merging block and information exchange block. The feature merging block can provide increased contextual information to pass to the subsequent network, which enables the network to learn more feature details to help detect unclear lane lines. The information exchange block is a novel block that combines the advantages of spatial convolution and dilated convolution to enhance the process of information transfer between pixels. The addition of spatial information allows the network to better detect occluded lane lines. Experimental results show that our proposed model can detect lane lines more robustly and precisely than state-of-the-art models in a variety of complex driving scenarios. Due to the development of deep learning, we can use convolutional neural networks to process images and help us solve some of the problems encountered in the field of unmanned driving, such as the lateral control of the car , predictThere are many difficulties encountered when performing lane detection in complex traffic driving scenes. Some examples of complex traffic driving scenarios are shown in Lane detection algorithms can be divided into two categories: one is based on image features that are extracted and then fitted , and theIn this paper, we propose a deep convolutional neural network to detect lane lines in a variety of complex traffic scenarios. We enhance the accuracy of lane detection by the network for complex scenes by increasing the amount of contextual information and enhancing the transmission of information between pixels. In general, the feature map may lose contextual information after the convolution operation in the non-bottleneck part of the network. Therefore, we design a feature merging block that includes a skip layer and factorized convolutions  to allowWe propose a robust lane detection model using vertical spatial features and contextual driving information that works well for unclear or occluded lanes in complex driving scenes, such as crowded scene, poor light condition, etc.The information exchange block and feature merging block are designed to make the proposed model use the contextual information effectively and only use the vertical spatial features combined with lane line distribution features to robustly detect unclear and occluded lane lines.We present many comparisons with other state-of-the-art lane detection models on the CuLane and TuSimple lane detection datasets. The experimental results show that our proposed model can detect the lane lines more robustly and precisely than others in the complex driving scenes.In summary, our main work is as follows.Early lane detection works were mainly used to assist the driving process of the vehicle. At that time, lane detection did not require a deep understanding of traffic scenes and only required the detection of ego lanes to meet the demands of applications. Beyeler et al.  proposedXing et al.  comparedFurthermore, some people use the advantages of recurrent neural networks to process continuous time information for lane detection. Li et al.  used a rIn this section, we describe the proposed network architecture used to detect lanes in detail. The network architecture is shown in The shape of a lane is thin and long, and it accounts for a low proportion of the pixels in a traffic scene image. This requires that the quality of the feature map generated by the encoding network is high and that the feature map contains enough context information. In this section, we discuss several important blocks in the encoding network. The structure of the encoding network is shown in The semantic information of the feature map output by the encoding network is critical to the quality of the lane detection network. The larger the receptive field of the feature map is, the richer the semantic information. Downsampling is very useful for increasing the receptive field of the feature map . IncreasReLU  with the non-bottleneck-1D three times in the dilated convolutional block (layer 7). The dilation rates  indicate that four non-bottleneck-1D blocks are used, and the dilation rate of convolution in each block corresponds to . Vertical spatial convolution (layer 6) is equivalent to proposing to train a 3-D kernel tensor K to transmit spatial information in the vertical direction and then pass it in the form of residuals layer by layer. It is verified by experiments that this convolution method can indeed effectively promote the flow of spatial information. Taking the downward spatial convolution as an example, the formula  can be eThe task of this decoding branch is to enlarge the size of the feature map, fine tune the details , and finIn this branch, we use the decoding structure in ERFNet , which pInspired by the work of Pan et al. , we use This branch has two functions: (1) The process of weighting the loss of the road branch according to the total loss helps the network predict the lane probability map. The position relationship with other lanes and the existence of lanes have certain impacts on lane detection. (2) We replace the continuous lane with a series of points at fixed intervals. According to this branch, we can accurately select some points from the lanes on the probability map to accurately generate the final prediction map. In this way, the final prediction map has few error points, and the fitting effect of the curve is improved.i-th element is predicted to be a positive sample, i-th element, and N denotes the number of pixels.First, we introduce the loss function of the decoding branch for predicting the existence of lane lines. We use binary cross-entropy loss, which can solve the problem of binary classification. The main formula isThe next step for the semantic segmentation of lane lines is to apply cross-entropy loss (https://github.com/TuSimple/tusimple-benchmark/tree/master/doc/lane_detection) and CULane lane detection datasets.In this section, we verify the effectiveness of the proposed model through a large number of experimental results on TuSimple lane detection challenge  between the predictions and their corresponding ground truths. Lanes with calculated IoU values greater than a certain threshold are considered to be true positives  denotes F1-measure that IoU threshold is m. Generally, F1 (0.3) and F1 (0.5) are selected for experiments to facilitate comparison with other models using the same data set ,21,22.Our proposed network model is inspired by ERFNet , and verThe experimental results shown in The designed information exchange block is composed of a vertical spatial convolution and a multiscale dilated convolution. The purpose of this experiment is to discuss the use of dilated convolution with different dilation rates in the designed information exchange block. As mentioned earlier, our use of dilated convolution is based on the non-bottleneck-1D block. Next, we carry out three groups of experiments with different dilation rate combinations in In this experiment, we compare the effects of different dilation rate combinations for the dilated convolution blocks on the results. As shown in The spatial convolution module is located in the top hidden layer, and the feature information it contacts is sufficient. In the information exchange block, we use spatial convolution to enhance the information exchange between layers in the feature map. As shown in As we can see from In this section, we compare the proposed model with other lane detection models on the TuSimple and CULane lane detection datasetsfrom two points of view: a qualitative evaluation and a quantitative evaluation.TuSimple lane detection benchmark datasetAs shown in CULane datasetTuSimple lane detection benchmark datasetAccording to the evaluation scores shown in CULane datasetIn In short, the qualitative and quantitative experiments on TuSimple and CULane datasets show that our proposed model can robustly detect lanes in complex driving scenarios.According to the results in As can be seen in In addition, lane detection at crossroad is difficult for all models, so FP is used to compare the lane detection results in this scene. In fact, as shown in In short, we propose a robust lane detection model inspired by the ERFNet for complex traffic driving scenes. In this work, we strengthen the use of contextual information and vertical spatial features in our model by two designed blocks. More contextual information and the useful vertical spatial features can significantly enhance unclear and occluded lane detection. After a number of verification experiments were analyzed, we conclude that the proposed model is more robust for unclear and occluded lane detection than others.The limitation of these two blocks is that many of the information transmitted to the subsequent network is useless. We consider using the attention mechanism to select the region of interest, which can effectively filter information and accelerate the network’s inference time. The parameter size of the proposed model is 23.2 M, and the running time of processing one image with a single NVIDIA Titan XP 12 GB GPU  is 188.7 ms. This shows that although our model can robustly solve lane detection in the complex driving scenarios, but it still cannot meet real-time requirements. In future work, we will consider improving the model to perform lane detection in real time and make the model perform better in crossroad and curved scenes.


Acoustic wave resonators are promising candidates for gravimetric biosensing. However, they generally suffer from strong acoustic radiation in liquid, which limits their quality factor and increases their frequency noise. This article presents an acoustic radiation-free gravimetric biosensor based on a locally resonant surface phononic crystal (SPC) consisting of periodic high aspect ratio electrodes to address the above issue. The acoustic wave generated in the SPC is slower than the sound wave in water, hence it prevents acoustic propagation in the fluid and results in energy confinement near the electrode surface. This energy confinement results in a significant quality factor improvement and reduces frequency noise. The proposed SPC resonator is numerically studied by finite element analysis and experimentally implemented by an electroplating-based fabrication process. Experimental results show that the SPC resonator exhibits an in-liquid quality factor 15 times higher than a conventional Rayleigh wave resonator at a similar operating frequency. The proposed radiation suppression method using SPC can also be applied in other types of acoustic wave resonators. Thus, this method can serve as a general technique for boosting the in-liquid quality factor and sensing performance of many acoustic biosensors. Electrochemical biosensors detect signal variations in potential, current, or conductivity3. Thermal biosensors use the biochemical-reaction-induced temperature variation as the signal4. Optical biosensors detect the adsorption or emission of light at specific wavelengths5. Mass-sensitive biosensors sense surface mass variation due to the binding of analytes to bioreceptors6. Novel types of biosensors, such as photothermal7 and photoelectrochemical10 biosensors, have also been increasingly studied. These sensors use light as the excitation source while implementing detection based on temperature  or electrical current  variations. Among these different types, optical biosensors based on fluorescent labels or the label-free surface plasmon resonance technique are the most widely used for protein and aptamer detection13. However, due to the relatively complex setup of the optical detection scheme, optical sensors remain relatively costly and hard to miniaturize.The rapid and decentralized detection of biomolecules has been increasingly demanded for various applications, such as infectious disease diagnosis and food safety tests. This demand has been particularly evident during the recent outbreak of the novel coronavirus (COVID-19), where the throughput of time-consuming laboratory virus tests significantly delayed the diagnosis of the disease. In recent years, various techniques have been developed to meet these rising needs, which can be classified into four major categories: electrochemical, thermal, optical, and mass-sensitive biosensors15. They can reach a higher level of integration at lower cost, as they do not require the use of peripheral equipment, such as excitation light sources. As their operating principle relies on the direct detection of an added mass to the surface of the sensor and on the direct measurement of the corresponding electroacoustic response, the entire detection scheme is intrinsically embedded into the acoustic device, leading to small-sized, low-cost sensors that can be easily fitted into a small microfluidic chamber. In addition, as mass variation is a physical signal that exists in any type of analyte–bioreceptor binding reaction, mass-sensitive sensors can be applied to all types of biomolecule detection, while other biosensors are limited by their signal type and require the specific design of the detection protocol. For example, potentiometric electrochemical biosensors require the analyte binding reaction to generate a potential variation so that it can be detected. Despite these advantages, acoustic wave resonators generally suffer from strong acoustic radiation in liquid, which decreases their quality factor (Q) and increases the signal noise. To maintain operation in liquid, acoustic wave resonators for biosensing are usually designed to operate in shear modes. When the movement of the shear wave is parallel to the liquid–solid interface, the mechanical motion transferred to the liquid is reduced compared to vertically polarized waves18. The acoustic radiation, however, cannot be eliminated, as the horizontal friction between the solid and water particles still conveys energy. The complete suppression of acoustic radiation can only be achieved by completely preventing wave propagation in the liquid. This scenario requires the velocity of the acoustic wave generated in the solid substrate to be lower than the sound velocity in water, which does not occur in natural materials. The acoustic wave velocity in all piezoelectric substrates is indeed always higher than the sound velocity in water because of the large elastic constants of solid materials19.Mass-sensitive biosensors based on acoustic wave resonators are competitive alternatives to optical biosensors20 and Lamb waves21. In this paper, we exploit this idea for the realization of SPC resonators operating in liquid. The proposed SPC resonator is theoretically studied by the finite element method (FEM) and experimentally implemented by the classical lithography, electroplating, and molding ) process. By incorporating SPC with interdigitated transducers (IDTs), we find that the velocity of Rayleigh waves can be reduced to a value lower than the velocity of the sound in water. This successfully stops the propagation of the acoustic wave in water and eliminates acoustic radiation. Because of the complete suppression of radiation, the in-liquid Q factor of the resonator is improved by more than 15 times compared to a conventional Rayleigh wave resonator working in the same frequency range. In addition to the slowing down of the phase velocity, the group velocity is also found to be reduced to almost zero, hence suppressing energy propagation in the horizontal plane. This result enables the use of zero or a small number of reflectors when constructing a resonator, therefore significantly reducing the sensor size and fabrication cost. Moreover, the high aspect ratio electrodes constituting the SPC naturally lead to an increase in the surface-to-volume ratio of the device and hence increase the mass sensitivity. The proposed acoustic radiation suppression method can also be applied in other types of acoustic waves, which makes it a general technique that can significantly push forward the performance limit of many acoustic biosensors.It was, however, reported that one-dimensional surface phononic crystals (SPCs) made of periodic high aspect ratio electrode strips can be used to significantly slow down Rayleigh waves22. Because of the low group velocity in the horizontal plane, only 20 reflector strips are placed on the two sides of the IDTs to enhance the resonance. This number is much smaller than that used in conventional SAW resonators, which usually require hundreds of reflector strips23. The resonance frequency of the device is determined together by the electrode geometry, electrode periodicity, and materials of the electrode and piezoelectric substrate.Figure 24. They are widely used in the detection of human immunoglobulins or pathogens, such as viruses and bacteria. Less specific bioreceptors, such as functionalized nanoparticles25 and bioimprinted polymers27, can be used for the detection of small biomolecules that can serve as biomarkers for early disease diagnosis. Once the detection targets bind with the bioreceptors, the additional mass attached to the device surface results in a twofold variation in the SPC resonance. First, the attached molecules increase the mass of the high aspect ratio electrodes, which reduces their mechanical resonance frequency. Second, the additional mass reduces the surface acoustic wave velocity due to the classical mass loading effect also observed in surface acoustic wave resonators18. As the SPC resonance is a coupling between the mechanical resonance of the high aspect ratio electrodes and the surface acoustic wave, the combination of the above two effects reduces the SPC resonance frequency. By building an oscillator-based frequency readout circuit with the SPC resonator29, the sensor response can be converted to real-time digital signals.Figure If the acoustic wave velocity is reduced to a value lower than the sound velocity in water, its propagation in water is inhibited. This eliminates the acoustic radiation of the wave and thus enables high Q resonance in liquid. By exploiting this principle, we used SPC made of periodic high aspect ratio electrodes to slow down the surface wave on a lithium niobate substrate. The SPC induces a hybridization between the Rayleigh-type surface wave and the elastic resonance of the high aspect ratio electrodes. This hybridization results in the occurrence of hybrid modes with velocities directly conditioned by the geometrical characteristics of the electrodes. Figure Dispersion curves providing information on the group and the phase velocities constitute a very important design tool for acoustic devices. Figure ves Fig.  of theseA scanning electron microscopy (SEM) image of the fabricated device is shown in Fig. 30. Resonators with high quality factors will lead to lower frequency noise in the final sensor oscillator.The impedance curves of the resonators fabricated with these different photoresists are shown in Fig. The overall performance of a gravimetric biosensor can be described by its limit of detection (LOD), which is obtained by2) for the pPR and nPR SPC resonators, respectively. The good agreement between the full coverage mass sensitivities of the pPR and nPR SPC resonators can be accounted for by their similar surface areas under full coverage conditions. This result also reveals that the electrode profile does not affect the mass sensitivity of the SPC when the mass loading is homogenous on the entire surface. As expected, the mass sensitivity for full surface coverage loading is significantly higher than the mass sensitivity for loading only on the top of the electrode because of the much larger loading area. For comparison, the mass sensitivity of the widely used 36° Y LiTaO3-based SH-SAW sensing device, here working at 120 MHz, is also simulated. The corresponding simulation unit cell is shown in Fig. 2), which agrees well with the experimental results reported by Barie et al.31. Their 36° Y LiTaO3 SH-SAW operating at 380 MHz showed a 25 kHz response to the adsorption of a bovine serum albumin monolayer that has a surface mass of 200 ng/cm2. Considering that the mass sensitivity is proportional to the square of the operating frequency, the equivalent mass sensitivity at 120 MHz is 12.46 Hz/(ng/cm2), which is similar to our simulated SH-SAW sensitivity. This comparison shows that the proposed SPC biosensor can exhibit a mass sensitivity close to six times higher than that of conventional SH-SAW biosensors, which is due to the higher surface-to-volume ratio of the high aspect ratio electrodes.The mass sensitivity under homogeneous loading conditions, or full coverage mass sensitivity, was then obtained by the same FEM simulation model. A polymer layer (PMMA) covering the entire device surface was added as the mass loading layer. The device frequency response as a function of added mass is simulated by changing the PMMA layer density. The simulated unit cells for the pPR and nPR SPC resonators operating at 120 MHz are shown in Fig. As mentioned in the “Introduction” section, the usual strategy for in-liquid acoustic sensing relies on the use of shear-polarized acoustic modes. The shear polarization indeed minimizes mechanical motion transfer to water. However, it does not fully prevent acoustic radiation in water: the wave velocity in the solid substrate remains higher than the sound velocity in liquid and coupling with the vertically polarized mode generally occurs. This radiation loss is one of the major limitations of these devices in achieving a high Q factor for in-liquid sensing. In contrast, the SPC resonator proposed in this work relies on the complete suppression of acoustic radiation in water; this suppression is accomplished by a significant slowing down of acoustic wave propagation in the solid substrate due to the hybridization mechanism between localized modes in the electrodes and the surface wave. Due to the complete suppression of acoustic radiation, the energy leakage can be theoretically fully stopped, hence enabling high Q factor in-liquid sensing. In the present work, the Q factor of the SPC resonators is mostly limited by the electroplating process. The sidewall surface roughness and the overall process inhomogeneity result in structural defects breaking the periodicity of the IDTs, which limits further improvement in the quality factor. Nevertheless, this technological shortcoming can be overcome, notably by using alternative thick-film deposition techniques, such as thermal evaporation and chemical vapor deposition. Another limitation of the SPC biosensor compared to conventional SAW devices is that it involves a more complex fabrication process. Although it is a trade-off to achieve better performance, the added cost will not be significant in a complete sensing system that includes other components, such as microfluidic channels and readout circuits.The proposed method for acoustic radiation suppression is applied here to devices initially operating on elliptically polarized Rayleigh waves. This method can be more generally transposed to any IDT-based acoustic wave resonator, including SH-SAW or Love-wave acoustic resonators. The combination of shear mode polarization and acoustic radiation suppression has the potential to significantly advance the performance boundary of acoustic wave biosensors.2) were obtained by the pPR process. A comparison with a Rayleigh SAW resonator revealed that the SPC could improve the Q factor of the resonator by 15 times. The effect was demonstrated here for resonators operating on vertically polarized waves, and it could also be combined with existing shear mode acoustic wave resonators. This proposed biosensor has the potential to significantly advance the performance boundary of current acoustic wave biosensors.In summary, we proposed a gravimetric biosensor based on an SPC resonator that can achieve acoustic radiation-free operation in liquid. The SPC induced a hybridization between a Rayleigh-type surface wave and the elastic resonance of the high aspect ratio electrodes, which led to strong confinement of the elastic energy at the electrode–substrate interface. The acoustic wave velocity was then reduced to be lower than the speed of sound in water. This mechanism resulted in the complete suppression of acoustic radiation, leading to high Q resonance in liquid. This device principle was validated by FEM analysis and experimentally implemented through the fabrication of SPC resonators using the LIGA process. Q factors on the order of 50 and a mass sensitivity of 12.92 Hz/. It should be noted that both the IDTs and bus bars were electroplated, which meant that the IDTs were mechanically clamped by the bus bars in their electrical connection nodes. The device was then immersed in a Microposit 1165 remover to strip the photoresist mold. Reactive ion etching (RIE) was then used to remove the copper and titanium seed layers between the nickel electrodes to define the electrically isolated IDT fingers. Subsequently, 200 nm of silicon dioxide was deposited on the sensor surface using chemical vapor deposition. This layer was used as a passivation layer and could also provide an interface for bioreceptor immobilization. Another photolithography step was then performed to create the photoresist etching mask for the area excluding the pads that will be used for external electrical connection. The removal of silicon dioxide covering the contact pads was completed by another RIE process. The complete process flow is shown in Fig. The variation in the nickel film thickness across the wafer was exploited for the calculation of the mass sensitivity of the sensor because the small height difference of the nickel electrodes across the substrate caused a natural mass loading variation for the sensor, which changed its resonance frequency. The thickness of the nickel layers was measured by a profilometer.ƒ and The Q factor of the SPC resonator was used to evaluate the frequency stability (frequency noise) of the sensor. It was calculated from its impedance by the following equation:Supplemental material