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We report on a laboratory experiment testing the predictions of the Diamond–Mortensen–Pissarides (DMP) search-and-matching model, which is a workhorse, decentralized model of unemployment and the labor market. We focus on the job vacancy posting problem that firms face in the DMP model. We explore the model's comparative statics predictions concerning variations in the separation rate, the vacancy posting cost, and the firm's surplus earned per employee. Across all treatments, we find strong evidence for an inverse relationship between vacancies and unemployment, consistent with the Beveridge curve. We also find that the results of our various comparative statics exercises are in-line with the predictions of the theory.

The study of approximate matching in the Massively Parallel Computations (MPC) model has recently seen a burst of breakthroughs. Despite this progress, we still have a limited understanding of maximal matching which is one of the central problems of parallel and distributed computing. All known MPC algorithms for maximalmatching either take polylogarithmic time which is considered inefficient, or require a strictly superlinear space of n1+Ω(1) per machine. In this work, we close this gap by providing a novel analysis of an extremely simple algorithm, which is a variant of an algorithm conjectured to work by Czumaj, Lacki, Madry, Mitrovic, Onak, and Sankowski [15]. The algorithm edge-samples the graph, randomly partitions the vertices, and finds a random greedy maximal matching within each partition.We show that this algorithm drastically reduces the vertex degrees. This, among other results, leads to an O(log log Δ) round algorithm for maximal matching with O(n) space (or even mildly sublinear in n using standard techniques). As an immediate corollary, we get a 2 approximate minimum vertex cover in essentially the same rounds and space, which is the optimal approximation factor under standard assumptions. We also get an improved O(log log Δ) round algorithm for 1 + ε approximate matching. All these results can also be implemented in the congested clique model in the same number of rounds. [ABSTRACT FROM AUTHOR]

When well-known food resources are running out, animals extinguish their foraging behavior in that food patch and increasingly work for reward-related information to decrease outcome uncertainty. In the absence of such information, a potentially successful strategy consists of spending more time and effort searching for profitable locations—a phenomenon known from extinction learning experiments conducted in conventional conditioning chambers. Here, we tested this hypothesis by means of a semi-natural “foraging board” allowing pigeons to move and look for food items inside perforated holes. The holes could be covered with a slit plastic tape, hiding the food items they contained while making them accessible to pigeons. Our goal was to determine how pigeons forage on hidden food items in an area associated with uncertainty (one in three holes baited, on average) when visible or hidden food items were available in an adjacent area associated with certainty (each hole baited). The number of food items was equivalent in both areas. We expected longer time spent and more pecks given in the uncertain vs. certain area with the food items visible in the certain area, as well as longer time spent and more pecks given per visit in the uncertain vs. certain area with the food items either visible or hidden in the certain area. Our results confirm these predictions.

Multi-access edge computing (MEC), as a computing model that provides services on the user side, can effectively solve the problems of high delay and resource shortage in traditional cloud computing when processing massive data. However, existing edge computing resources are still limited, and difficult to provide services to users in inaccessible remote areas. Considering that unmanned aerial vehicle (UAV) has the advantages of easy deployment, high flexibility and low cost, a UAV-assisted MEC hierarchical computation offloading framework is proposed. Firstly, contract theory is used to solve the information asymmetry problem between the platform and the UAV, and the UAV is encouraged to provide computing services. By analyzing the attributes and conditions of feasible contracts, the optimal contract is designed using the Lagrange multiplier method. Secondly, by constructing the preference set between UAV and mobile user (MU), a mobile user and unmanned aerial vehicle bilateral matching (MUBM) algorithm is proposed to establish the connection between user tasks and UAV computing resources. Finally, the feasibility and effectiveness of the contract were verified through experiments. The experimental results also prove the stability of the MUBM. [ABSTRACT FROM AUTHOR]

Background: Methods for matching in longitudinal cohort studies, such as sequential stratification and time-varying propensity scores, facilitate causal inferences in the context of time-dependent treatments that are not randomized where patient eligibility or treatment status changes over time. The tradeoffs in available approaches have not been compared previously, so we compare two methods using simulations based on a retrospective cohort of patients eligible for weight loss surgery, some of whom received it. Methods: This study compares matching completeness, bias, coverage, and precision among three approaches to longitudinal matching: (1) time-varying propensity scores (tvPS), (2) sequential stratification that matches exactly on all covariates used in tvPS (SS-Full) and (3) sequential stratification that exact matches on a subset of covariates (SS-Selected). These comparisons are made in the context of a deep sampling frame (50:1) and a shallow sampling frame (5:1) of eligible comparators. A simulation study was employed to estimate the relative performance of these approaches. Results: In 1,000 simulations each, tvPS retained more than 99.9% of treated patients in both the deep and shallow sampling frames, while a smaller proportion of treated patients were retained for SS-Full (91.6%) and SS-Selected (98.2%) in the deep sampling frame. In the shallow sampling frame, sequential stratification retained many fewer treated patients (73.9% SS-Full, 92.0% SS-Selected) than tvPS yet coverage, precision and bias were comparable for tvPS, SS-Full and SS-Selected in the deep and shallow sampling frames. Conclusion: Time-varying propensity scores have comparable performance to sequential stratification in terms of coverage, bias, and precision, with superior match completeness. While performance was generally comparable across methods, greater match completeness makes tvPS an attractive option for longitudinal matching studies where external validity is highly valued. [ABSTRACT FROM AUTHOR]

Ride-sharing services have attracted significant interest due to overcrowding, limited energy resources, and environmental concerns. This study proposes a mathematical programming model that integrates user preferences into the ride-sharing problem with transfer. Passenger transfer in ride-sharing problems addresses the limitations of the matching process, especially in less-populated areas. It allows passengers to be dropped off at meeting points and continue with another driver. Moreover, considering user preferences in ride-sharing systems is crucial for enhancing efficiency and user satisfaction. Accordingly, we propose a Preference-Driven Matching Algorithm for the matching process. Our proposed algorithm captures user preferences and provides potential matches. In addition, we introduce an Iterative Enhance-and-Optimize Algorithm capable of producing high-quality solutions within short computational times. We evaluate the efficiency of these approaches across various instances, focusing on real-scale scenarios. Based on the results, the model with preferences demonstrates effective performance compared to other methods. Our findings underscore the importance of user preferences in optimizing ride-sharing problems and highlight the trade-off between efficiency and user satisfaction. By incorporating user preferences, our approach results in higher user satisfaction, a more responsive and efficient system with reduced response times, and increased demand and revenue by servicing more users. [ABSTRACT FROM AUTHOR]

As open-source communities and other peer production projects face the challenge of sustaining themselves over time, the role of offline gatherings in fostering community resilience becomes a vital question. This study centres on the potential of offline social interactions as a means to mitigate declines within such communities, using Wikipedia as a case example. Using a comprehensive dataset spanning informal meetups within the German-language Wikipedia community from 2001 to 2020 and combining it with large scale online activity data, this study investigates the relationship between offline gatherings and online contribution behaviour. Results show that attending meetups has a positive effect on contributing towards Wikipedia both in the short and long term. By shedding light on the significance of offline social interactions in bolstering online communities, this study offers valuable insights into potential strategies for sustaining collaborative online environments amidst broader declines and further shows how offline and online activities intertwine. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to investigate and highlight the most important factors influencing the candidate's selection for residency matching by program directors of surgical and non-surgical specialties in Saudi Arabia. Method: This cross-sectional study was conducted in the Central, Eastern, Western, Northern, and Southern regions of Saudi Arabia from February 1, 2023, to August 31, 2023. A total of sixty-one program directors completed a questionnaire, which was adapted and validated from a previous study with permission and tailored to meet the objectives of this research. Results: The mean age of the study population was 40.2 years, with surgical specialty program directors being older at 41.7 years and nonsurgical specialty program directors being younger at 39.6 years. In both cases, the highest importance was given to 'Applicant's attitude and professionalism', followed in surgical specialties by 'Doing clinical rotations in the PD institution' and 'Performance in clinical rotation during internship' in non-surgical specialties. with a mean score of 4.13 and 4.95, respectively. The importance of 'The impression/opinion of current residents' has had a certain importance in both specialties. While the number of research projects was prioritized more by surgical PDs (38.6%) compared to non-surgical PDs (29.4%). Conclusion: This study highlights the critical role of professionalism and a positive attitude in clinical rotations and interviews for program acceptance in Saudi Arabia. The significance of letters of recommendation and research focus varies between surgical and non-surgical program directors. Program directors should adopt effective recruitment strategies that incorporate practical implications during internships. Key messages: This research focuses on the evolving area of residency applicant selection criteria in Saudi Arabia. In 2024, over 6400 individuals were nominated for residency programs across the country, with approximately 5100 successfully matched following interviews. These statistics underscore the complexity and competitiveness of the matching system in Saudi Arabia, underscoring the urgency for similar research. Such studies are essential to provide guidance to future applicants, helping them navigate the selection process effectively and avoid common pitfalls. [ABSTRACT FROM AUTHOR]

Firms seeking business partners and individuals seeking life partners face several challenges in addition to finding available candidates. One of these challenges is uncertainty about a candidate's compatibility with the match-seeker on various subjective criteria. Another challenge is authentication of objective quality features, particularly in online settings where credentials can be easily misrepresented. Online matching platforms can address these challenges through counseling services that help assess mutual compatibility of match-seekers and authentication services to validate match-seekers' credentials. Using a stylized model, we show that the platform's decisions to offer counseling and authentication services are influenced by match-seeker behavior in response to factors such as the platform's counseling capability, the composition of the matching market, and the interactions between the two services. This leads to optimal strategies for the platform that are not obvious and can even be counterintuitive. For instance, offering better counseling does not necessarily result in higher revenues for the platform. And it may be optimal for the platform to reduce its access fee when it decides to offer an authentication service. We also show that when the platform's counseling capability is modest, an increase in this capability increases the value of authentication (i.e., counseling complements authentication); however, when the platform's counseling capability is high, counseling and authentication become substitutes, because narrowing the search to only high-value candidates based on authentication can exclude some compatible candidates. Our analysis and results provide valuable insights for platform operators on the relative value of counseling and authentication, and for researchers studying matching platforms for vertically and horizontally differentiated markets. This paper was accepted by Hemant Bhargava, information systems. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2021.03807. [ABSTRACT FROM AUTHOR]

The development of green products in manufacturing enterprises is challenged by limited independent innovation capabilities and insufficient green technology. Based on knowledge-based theory, this study investigates the influence of boundary-spanning green technology search (BGTS) and technology integration capability (TIC) on green product development performance (GPDP). Using polynomial regression analysis with response surface methodology (PRA with RSM) on data from 341 companies, the following findings were obtained: (1) Higher levels of BGTS and TIC congruence are associated with higher GPDP compared to lower levels of congruence. (2) The degree of discrepancy between the BGTS and TIC has an inverted U-shaped relationship with GPDP. (3) GPDP is higher in the "low BGTS–high TIC" combination than in the "high BGTS–low TIC" combination. (4) Green technology innovation capability mediates the relationship between BGTS-TIC congruence and GPDP. (5) Strategic foresight positively moderates the relationship between the BGTS-TIC congruence and green technology innovation capability. These findings enrich the research content of organizational search theory, deepen the research of green technology innovation, expand research on the development of green products, and provide a decision-making reference for manufacturing enterprises' green transition practices. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the concept of Conditional Deployable Biometrics (CDB), designed to deliver consistent performance across various biometric matching scenarios, including intra-modal, multimodal, and cross-modal applications. The CDB framework provides a versatile and deployable biometric authentication system that ensures reliable matching regardless of the biometric modality being used. To realize this framework, we have developed CDB-Net, a specialized deep neural network tailored for handling both periocular and face biometric modalities. CDB-Net is engineered to handle the unique challenges associated with these different modalities while maintaining high accuracy and robustness. Our extensive experimentation with CDB-Net across five diverse and challenging in-the-wild datasets illustrates its effectiveness in adhering to the CDB paradigm. These datasets encompass a wide range of real-world conditions, further validating the model's capability to manage variations and complexities inherent in biometric data. The results confirm that CDB-Net not only meets but exceeds expectations in terms of performance, demonstrating its potential for practical deployment in various biometric authentication scenarios. [ABSTRACT FROM AUTHOR]

Abstract Background Methods for matching in longitudinal cohort studies, such as sequential stratification and time-varying propensity scores, facilitate causal inferences in the context of time-dependent treatments that are not randomized where patient eligibility or treatment status changes over time. The tradeoffs in available approaches have not been compared previously, so we compare two methods using simulations based on a retrospective cohort of patients eligible for weight loss surgery, some of whom received it. Methods This study compares matching completeness, bias, coverage, and precision among three approaches to longitudinal matching: (1) time-varying propensity scores (tvPS), (2) sequential stratification that matches exactly on all covariates used in tvPS (SS-Full) and (3) sequential stratification that exact matches on a subset of covariates (SS-Selected). These comparisons are made in the context of a deep sampling frame (50:1) and a shallow sampling frame (5:1) of eligible comparators. A simulation study was employed to estimate the relative performance of these approaches. Results In 1,000 simulations each, tvPS retained more than 99.9% of treated patients in both the deep and shallow sampling frames, while a smaller proportion of treated patients were retained for SS-Full (91.6%) and SS-Selected (98.2%) in the deep sampling frame. In the shallow sampling frame, sequential stratification retained many fewer treated patients (73.9% SS-Full, 92.0% SS-Selected) than tvPS yet coverage, precision and bias were comparable for tvPS, SS-Full and SS-Selected in the deep and shallow sampling frames. Conclusion Time-varying propensity scores have comparable performance to sequential stratification in terms of coverage, bias, and precision, with superior match completeness. While performance was generally comparable across methods, greater match completeness makes tvPS an attractive option for longitudinal matching studies where external validity is highly valued.

Abstract Ride-sharing services have attracted significant interest due to overcrowding, limited energy resources, and environmental concerns. This study proposes a mathematical programming model that integrates user preferences into the ride-sharing problem with transfer. Passenger transfer in ride-sharing problems addresses the limitations of the matching process, especially in less-populated areas. It allows passengers to be dropped off at meeting points and continue with another driver. Moreover, considering user preferences in ride-sharing systems is crucial for enhancing efficiency and user satisfaction. Accordingly, we propose a Preference-Driven Matching Algorithm for the matching process. Our proposed algorithm captures user preferences and provides potential matches. In addition, we introduce an Iterative Enhance-and-Optimize Algorithm capable of producing high-quality solutions within short computational times. We evaluate the efficiency of these approaches across various instances, focusing on real-scale scenarios. Based on the results, the model with preferences demonstrates effective performance compared to other methods. Our findings underscore the importance of user preferences in optimizing ride-sharing problems and highlight the trade-off between efficiency and user satisfaction. By incorporating user preferences, our approach results in higher user satisfaction, a more responsive and efficient system with reduced response times, and increased demand and revenue by servicing more users.

Abstract Purpose The aim of this study is to investigate and highlight the most important factors influencing the candidate’s selection for residency matching by program directors of surgical and non-surgical specialties in Saudi Arabia. Method This cross-sectional study was conducted in the Central, Eastern, Western, Northern, and Southern regions of Saudi Arabia from February 1, 2023, to August 31, 2023. A total of sixty-one program directors completed a questionnaire, which was adapted and validated from a previous study with permission and tailored to meet the objectives of this research. Results The mean age of the study population was 40.2 years, with surgical specialty program directors being older at 41.7 years and nonsurgical specialty program directors being younger at 39.6 years. In both cases, the highest importance was given to ‘Applicant’s attitude and professionalism’, followed in surgical specialties by ‘Doing clinical rotations in the PD institution’ and ‘Performance in clinical rotation during internship’ in non-surgical specialties. with a mean score of 4.13 and 4.95, respectively. The importance of ‘The impression/opinion of current residents’ has had a certain importance in both specialties. While the number of research projects was prioritized more by surgical PDs (38.6%) compared to non-surgical PDs (29.4%). Conclusion This study highlights the critical role of professionalism and a positive attitude in clinical rotations and interviews for program acceptance in Saudi Arabia. The significance of letters of recommendation and research focus varies between surgical and non-surgical program directors. Program directors should adopt effective recruitment strategies that incorporate practical implications during internships.

During COVID-19, the Norwegian Government provided compensation to amend firms’ decreased revenues, yet it should be neutral and tailored to losses only. However, firm resources or institutional factors may have influenced the compensation, which we study here. Survey data showed a high probability of compensation among large firms, although they were not hit particularly hard by COVID-19. Also, compensation was prevalent for firms in the hospitality, tourism, and culture industry, and a likely explanation is that they were hit hard. However, their probability of compensation was prevalent compared to firms in other industries, regardless of revenue losses. We assume that large firms’ compensation was due to their resources to apply for funding successfully, while institutional factors explained the compensation for firms in the hospitality, tourism, and culture industry.

During COVID-19, the Norwegian Government provided compensation to amend firms' decreased revenues, yet it should be neutral and tailored to losses only. However, firm resources or institutional factors may have influenced the compensation, which we study here. Survey data showed a high probability of compensation among large firms, although they were not hit particularly hard by COVID-19. Also, compensation was prevalent for firms in the hospitality, tourism, and culture industry, and a likely explanation is that they were hit hard. However, their probability of compensation was prevalent compared to firms in other industries, regardless of revenue losses. We assume that large firms' compensation was due to their resources to apply for funding successfully, while institutional factors explained the compensation for firms in the hospitality, tourism, and culture industry. [ABSTRACT FROM AUTHOR]

Blockchain received a vast amount of attention in recent years and is still growing. The second generation of blockchain, such as Ethereum, allows execution of almost any program in EVM, making it a global protocol for distributed applications. The code deployment and each operation performed in EVM cost the network fee called gas, whose price varies and can be significant. That is why code optimization and well-chosen algorithms are crucial in programming on the blockchain. This paper evaluates the gas usage of several exact pattern matching algorithms on the EVM. We also propose an efficient implementation of the algorithms in the Solidity/YUL language. We evaluate the gas fees of all the algorithms for different parameters (such as pattern length, alphabet size, and text size). We show a significant gas fee and execution time reduction with up to 22-fold lower gas usage and 55-fold speed-up compared to StringUtils (a popular Solidity string library). [ABSTRACT FROM AUTHOR]

The rich literature on online Bayesian selection problems has long focused on so-called prophet inequalities, which compare the gain of an online algorithm to that of a "prophet" who knows the future. An equally natural, though significantly less well-studied, benchmark is the optimum online algorithm, which may be omnipotent (i.e., computationally unbounded), but not omniscient. What is the computational complexity of the optimum online? How well can a polynomial-time algorithm approximate it? Motivated by applications in ride hailing, we study the above questions for the online stochastic maximum-weight matching problem under vertex arrivals. For this problem, a number of 1/2 -competitive algorithms are known. This is the best possible ratio for this problem, as it generalizes the original single-item prophet inequality problem. We present a polynomial-time algorithm, which approximates the optimal online algorithm within a factor of 0.51—strictly more than the best-possible constant against a prophet. In contrast, we show that it is PSPACE-hard to approximate this problem within some universal constant α<1. Funding: Financial support from the National Science Foundation [Grants CCF1763970, CCF1812919, and CCF191070], the Office of Naval Research [Grant N000141912550], and Cisco Research is gratefully acknowledged. [ABSTRACT FROM AUTHOR]

The paper reexamines an agent-based model of opinion formation under bounded confidence with heterogeneous agents. The paper is novel in that it extends the standard model of opinion dynamics with the assumption that interacting agents share the desire to exchange opinion. In particular, the interaction between agents in the paper is modeled via a dynamic preferential-matching process wherein agents reveal their preferences to meet according to three features: coherence, opinion difference, and agents' positive sentiments towards others. Only preferred matches meet and exchange opinion. Through an extensive series of simulation treatments, it follows that the presence of sentiments, on one hand, hardens the matching process between agents, which leads to less communication. But, on the other hand, it increases the diversity in preferred matches between agents and thereby leads to a better-integrated social network structure, which reflects in a reduction of the opinion variance between agents. Moreover, at combinations of (a) high tolerance, (b) low sensitivity of agents to opinion volatility, and (c) low levels of confidence, agents are occasionally drawn away from the consensus, forming small groups that hold extreme opinions. [ABSTRACT FROM AUTHOR]

Vehicle-borne mobile mapping systems (MMSs) have been proven as an efficient means of photogrammetry and remote sensing, as they simultaneously acquire panoramic images, point clouds, and positional information along the collection route from a ground-based perspective. Obtaining accurate matching results between point clouds and images is a key issue in data application from vehicle-borne MMSs. Traditional matching methods, such as point cloud projection, depth map generation, and point cloud coloring, are significantly affected by the processing methods of point clouds and matching logic. In this study, we propose a method for generating matching relationships based on panoramic images, utilizing the raw point cloud map, a series of trajectory points, and the corresponding panoramic images acquired using a vehicle-borne MMS as input data. Through a point-cloud-processing workflow, irrelevant points in the point cloud map are removed, and the point cloud scenes corresponding to the trajectory points are extracted. A collinear model based on spherical projection is employed during the matching process to project the point cloud scenes to the panoramic images. An algorithm for vectorial angle selection is also designed to address filtering out the occluded point cloud projections during the matching process, generating a series of matching results between point clouds and panoramic images corresponding to the trajectory points. Experimental verification indicates that the method generates matching results with an average pixel error of approximately 2.82 pixels, and an average positional error of approximately 4 cm, thus demonstrating efficient processing. This method is suitable for the data fusion of panoramic images and point clouds acquired using vehicle-borne MMSs in road scenes, provides support for various algorithms based on visual features, and has promising applications in fields such as navigation, positioning, surveying, and mapping. [ABSTRACT FROM AUTHOR]

Dynamic stochastic matching problems arise in a variety of recent applications, ranging from ridesharing and online video games to kidney exchange. Such problems are naturally formulated as Markov decision processes (MDPs) that are, however, intractable in general. To improve tractability, we investigate the linear programming-based approach to approximate dynamic programming. This approach can provide both feasible control policies and bounds on the MDPs' optimal policy value, which can be used to establish optimality gaps. However, the approximate linear programs (ALPs) resulting from this approach can often be difficult to solve. To address this computational challenge, we derive novel ALP reformulations that can be used for a broad class of dynamic stochastic matching problems that incorporate, among others, possible match failures and certain restrictions on feasible matchings. We show that these ALP reformulations can be solved efficiently and applied to a broad class of dynamic matching problems. In addition, our numerical results indicate that our ALP reformulations can produce tight bounds that allow us to establish near-optimal policy performance for a broad set of problem instances. Thus, ALP reformulations can present an attractive alternative for applications that involve dynamic stochastic matching. History: Accepted by Nicola Secomandi, Area Editor for Stochastic Models & Reinforcement Learning. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information (https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2021.0203) as well as from the IJOC GitHub software repository (https://github.com/INFORMSJoC/2021.0203). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/. [ABSTRACT FROM AUTHOR]

Background: Look-Alike, Sound-Alike (LASA) drugs pose significant risks to patient safety due to potential medication errors, primarily from confusion over drug names. Such issues are of global concern and are pervasive across healthcare settings. Objective: This study evaluated the similarity between the registered brand names of medication, specifically focusing on tablets and capsules that are commercially accessible in Thailand. Methods: This research analyzed secondary data from Thailand's Bureau of Drug Administration, focusing on tablets and capsules drugs. An orthographic analysis of the 18,108 registered items (as of January 2020) was performed, and similarities and differences were analyzed using Microsoft Excel. Attributes such as registration number, manufacturer details, active ingredients, dosage forms, and strength were considered when categorizing similar names. Results: Upon analyzing 18,108 registered tablets and capsules, four groups emerged from pairwise brand name similarity analysis: 1. Matching brand names from one pharmaceutical company with identical active pharmaceutical ingredients (APIs) but multiple registration numbers (66.47%). 2. Matching brand names from various pharmaceutical companies with the same active ingredients (33.03%). 3. Matching brand names from different pharmaceutical companies with different active ingredients (0.39%). 4. Matching brand names from the same pharmaceutical company with different active ingredients (0.11%). The "Tall Man Letter" principle was leveraged to examine potential resemblances among 18,108 Thai pharmaceutical brand names. Twelve terms exhibited notable similarities, with "AMINE," "HYDRO," and "PREDNIS" appearing most frequently. Conclusion: These results underscore the prevalence of LASA issues in drug brand names, potentially leading to confusion and errors in medication use, and highlight the need for system improvements to enhance patient safety. [ABSTRACT FROM AUTHOR]

A graph is well-covered if all of its maximal independent sets have the same size. A graph that remains well-covered upon the removal of any vertex is called a 1-well-covered graph. These graphs, when they have no isolated vertices, are also known asW2 graphs. It is well-known that every graph G W2 has two disjoint maximum independent sets. In this paper, we investigate connected W2 graphs with n vertices that contain a clique of size n/3. We prove that if the removal of two disjoint maximum independent sets from a graph G W2 leaves a clique of size at least 3, then G contains a clique of size n/3. Using this result, we provide a complete characterization of these graphs, based on eleven graph families. [ABSTRACT FROM AUTHOR]

Social scientists have long been interested in marital homogamy and its relationship with inequality. However, measuring homogamy is not straightforward, particularly when one is interested in assessing marital sorting based on multiple traits. In this paper, we argue that Separate Extreme Value (SEV) models not only generate a matching function with several desirable theoretical properties, but they are also suited for the study of multidimensional sorting. Specifically, we use rich small‐scale survey data to examine sorting among parents of school‐age children in Naples. We show that homogamy is pervasive; not only do men and women sort by age, education, and physical characteristics, but they also look for partners that share similar health‐related behavior and risk attitude. However, we also show that these marital patterns are well explained by a low number of dimensions, the most important being age cohort and human capital. In particular, human capital relates to various "outcomes" of the post‐matching relationship. Children of parents with a high human capital endowment perform better at school, although they report lower levels of subjective well‐being and of perceived quality of relationship with their mothers. [ABSTRACT FROM AUTHOR]

We introduce a new family of mechanisms for one-sided matching markets, denoted pick-an-object (PAO) mechanisms. When implementing an allocation rule via PAO, agents are asked to pick an object from individualized menus. These choices may be rejected later on, and these agents are presented with new menus. When the procedure ends, agents are assigned the last object they picked. We characterize the allocation rules that can be sequentialized by PAO mechanisms and the ones that can be implemented in a robust truthful equilibrium. We justify the use of PAO as opposed to direct mechanisms by showing that its equilibrium behavior is closely related to the one in obviously strategy-proof (OSP) mechanisms, but implements commonly used rules, such as Gale-Shapley DA and top trading cycles, which are not OSP implementable. We run laboratory experiments comparing truthful behavior when using PAO, OSP, and direct mechanisms to implement different rules. These indicate that agents are more likely to behave in line with the theoretical prediction under PAO and OSP implementations than their direct counterparts. This paper was accepted by Yan Chen, behavioral economics and decision analysis. Funding: This research is funded by the National Natural Science Foundation of China [Grant 72033006]. R. Hakimov was supported by the Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung [Project 100018_189152]. Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2023.4908. [ABSTRACT FROM AUTHOR]

Abstract This study assesses the impact of a voucher project that targeted vulnerable and poor pregnant women in Uganda. Highly subsidised vouchers gave access to a package of safe delivery services consisting of four antenatal visits, safe delivery, one postnatal visit, the treatment and management of selected pregnancy-related medical conditions and complications, and emergency transport. Vouchers were sold during the project’s operational period from 2016 to 2019. This study covers 8 out of 25 project-benefiting districts in Uganda and a total of 1,881 pregnancies, including both beneficiary and non-beneficiary mothers. Using a matching design, the results show a positive effect on the survival of new-born babies. The difference in the survival rate between the control group and the treatment group is 5.4% points, indicating that the voucher project reduced infant mortality by more than 65 per cent.

This paper presents the results of a numerical study of a planar antenna with a complex form factor. The antenna is based on a combination of two resonators, a disc resonator and a ring resonator. The feeding of the ring resonator is performed using a coplanar structure: pointwise by galvanic contact between the central conductor of the coplanar line and the ring resonator and by distributed electromagnetic coupling of the ring resonator and the aperture of the outer conductor of the coplanar line. The antenna was placed over a metal plane whose geometric dimensions were significantly larger than those of the antenna to exclude the influence of edge diffraction effects. In numerical simulation a complex approach including the method of semi-open resonator and the finite element method (FEM) implemented within the commercial package HFFS was used. The dependences of spectral, energy and polarization characteristics on material constants and frequency parameter have been investigated. It was found that within the framework of single-parameter optimization it is impossible to simultaneously achieve a high level of all important parameters. The values of frequencies of spectral lines in the spectral characteristics of the antenna are found with a relative error not worse than 1200 Hz. Frequency ranges within which there is no degeneration of oscillation types are established. The distributions of surface currents on the metal elements of the antenna, allowing to determine the position of phase centers of excitation, are presented. It is shown that the proposed antenna can provide an acceptable level of matching both at fixed frequencies and in sufficiently wide local frequency bands, reaching 11% with respect to the center frequency of the sub-band. The boundary values of gain coefficients in frequency bands are established. The simulation results allow to predict effective radiation with formation of practically single-lobe radiation pattern and presence of elliptical polarization.

Abstract The modular prediction model of high pressure common rail system was established to study the influence of high‐pressure pipeline integration matching on the fuel injection characteristics of common rail system. The influence of common rail volume on pressure building and pressure fluctuation in common rail tubes was analyzed. The influence of common rail volume on the matching of fuel injection frequency (number of fuel injectors) and fuel supply frequency (number of plunger pumps) was studied by using the control variable method, and the basic optimal solution of the system was obtained. The influence of the common rail structure on the fuel flow characteristics of the system was also studied. The matching relationship between high pressure tubing and common rail system is studied by introducing dimensionless numbers such as length‐diameter ratio of pipeline. The results demonstrate that the increase of the storage space of the accumulator can effectively reduce the fluctuation in the system, so that the injection volume increases slowly and then decreases rapidly, with a slope of −5.70 × 10−3 mm3. The increase of the diameter of the common rail makes the fuel flow characteristics become good first and then bad, and the increase of the length of the common rail can soothe the pressure fluctuations. The increase of the diameter of the link tube (LT) makes the fuel injection volume of the injector increase first and then decrease. The optimal VR solution for the LT is 0.0249 and the optimal ratio of the length to diameter of a pipeline solution is 55.10. The structure of the distribution tube and its matching to the common rail have little effect on the fuel flow characteristics. When the diameter and length of the injection tube are too large, the influence on the injection pressure of the injector is negatively correlated.

Green bonds are an increasingly used instrument to catalyze cash flows towards a low-carbon economy. Nonetheless, the existence of an actual price advantage is still uncertain. This research paper aims to assess whether there is a green bond premium (“greenium”) for green bonds relative to conventional bonds with similar characteristics, and how liquidity may affect the determination of a price advantage. It analyzes the yield differentials between green and conventional bonds using three different methods. First, a Nelson-Siegel-Svensson method is executed, estimating the premium both as the yield spreads and as the differentials in Z-spreads. Using a matching method and creating a sample of green and synthetic conventional bonds, the second methodology consists in calculating the distances between each categories’ yield for the same duration. Finally, a fixed-effect regression is performed to better control the liquidity bias. In the first case, a positive premium emerges when analyzing the yield spreads (+37.89 basis points) and the Z-spreads (+10.62 basis points). The second method mitigates the liquidity risk by creating a sample of synthetic bonds and reveals a yield spread of –15.89 basis points. Lastly, the regression method shows a negative greenium equal to –17.1487 basis points. Thus, a greenium emerges from all the three different methods, but its nature, sign, and real determinants are still uncertain. It is, therefore, not possible to conclude a definite price advantage for issuers of green bonds.

Abstract: Many demographic problems require models for partnership formation. We consider a model for matchings within a bipartite population where individuals have utility for people based on observed and unobserved characteristics. It represents both the availability of potential partners of different types and the preferences of individuals for such people. We develop an estimator for the preference parameters based on sample survey data on partnerships and population composition. We conduct simulation studies based on the Survey of Income and Program Participation showing that the estimator recovers preference parameters that are invariant under different population availabilities and has the correct confidence coverage.

A full-scale embankment on soft clays improved with prefabricated vertical drains (PVDs) have to be analyzed in 3D conditions due to a great number of vertical drains under an embankment. However, 3D analysis is very complex, time-consuming, and needs a powerful computer. Therefore, axisymmetric vertical drains have to be converted into equivalent plane-strain conditions for 2D analysis. Different matching approaches based on unit cell concept have been developed in the literature and the matching can be achieved by modifying the drain distance and/or soil permeability according with relatively simple instructions. This paper investigates verification of three different matching approaches to be used in the numerical analysis of full-scale embankment built on multiple vertical drains. The elasto-plastic soft soil model was used in the numerical analysis, and the results are compared with the laboratory and field measurements. The results of numerical analysis demonstrate that the matching methods are in extremely good agreement with the measurements if the effect of both the smear zone and discharge capacity are taken into consideration. It is seen that these methods provide practical solutions and important advantages to geotechnical engineers. [ABSTRACT FROM AUTHOR]

This study assesses the impact of a voucher project that targeted vulnerable and poor pregnant women in Uganda. Highly subsidised vouchers gave access to a package of safe delivery services consisting of four antenatal visits, safe delivery, one postnatal visit, the treatment and management of selected pregnancy-related medical conditions and complications, and emergency transport. Vouchers were sold during the project's operational period from 2016 to 2019. This study covers 8 out of 25 project-benefiting districts in Uganda and a total of 1,881 pregnancies, including both beneficiary and non-beneficiary mothers. Using a matching design, the results show a positive effect on the survival of new-born babies. The difference in the survival rate between the control group and the treatment group is 5.4% points, indicating that the voucher project reduced infant mortality by more than 65 per cent. [ABSTRACT FROM AUTHOR]

This study evaluates the effectiveness of public incentives in improving firm competitiveness, with a focus on the nationality of firm ownership as a distinguishing factor. Using panel data of incentivized and non-incentivized manufacturing firms in the Czech Republic from 2005 to 2019, we investigate the impact of the Czech investment incentives scheme on domestic and foreign firms' productivity, outputs, profitability, investment, and employment level. The analysis, which is based on a combination of propensity score matching with a difference-indifference technique estimator, reveals the presence of a substantial difference in the impact of the investment incentives between domestic and foreign firms. We find that access to the incentives has a negative effect on the output and employment of domestic beneficiary firms. In contrast, the results suggest that foreign recipient firms have a higher output and employ more physical capital and labor after receiving the incentives. Nonetheless, the results show that the incentives have no statistically significant effects on the profitability and productivity of both domestic and foreign firms. These findings are not sensitive to the matching methods employed. [ABSTRACT FROM AUTHOR]

The International Chess Federation (FIDE) imposes a voluminous and complex set of player pairing criteria in Swiss-system chess tournaments and endorses computer programs that are able to calculate the prescribed pairings. The purpose of these formalities is to ensure that players are paired fairly during the tournament and that the final ranking corresponds to the players' true strength order. We contest the official FIDE player pairing routine by presenting alternative pairing rules. These can be enforced by computing maximum weight matchings in a carefully designed graph. We demonstrate by extensive experiments that a tournament format using our mechanism (1) yields fairer pairings in the rounds of the tournament and (2) produces a final ranking that reflects the players' true strengths better than the state-of-the-art FIDE pairing system. [ABSTRACT FROM AUTHOR]

We investigate intersecting wage gaps by gender and nativity by comparing the wages between immigrant women, immigrant men, native women, and native men based on Western German survey data. Adding to the analytical diversity of the field, we do a full comparison of group wages to emphasize the relationality of privilege and disadvantage, and we use a nonparametric matching decomposition that is well suited to address unique group-specific experiences. We find that wage (dis)advantages associated with the dimensions of gender and nativity are nonadditive and result in distinct decomposition patterns for each pairwise comparison. After accounting for substantial group differences in work attachment, individual resources, and occupational segregation, unexplained wage gaps are generally small for comparisons between immigrant women, immigrant men, and native women, but large when either group is compared to native men. This finding suggests that the often presumed "double disadvantage" of immigrant women is rather a "double advantage" of native men. [ABSTRACT FROM AUTHOR]

Boosting Employment of Resettled Refugees Whether a resettled refugee finds employment in the United States depends in no small part on which host community they are first welcomed to. Every week, resettlement agencies are assigned a group of refugees who they are required to place in communities around the country. In "Dynamic Placement in Refugee Resettlement," Ahani, Gölz, Procaccia, Teytelboym, and Trapp develop an allocation system that recommends where to place an incoming refugee family with the aim of boosting the overall employment success. Should capacities in high-employment areas be used up as quickly as possible, or does it make sense to hold back for a perfect match? The simple algorithm, based on two-stage stochastic programming, achieves over 98% of the hindsight-optimal employment, compared with under 90% for the greedy-like approaches that were previously used in practice. Their algorithm is now part of the Annie™ MOORE optimization software used by a leading American refugee resettlement agency. Employment outcomes of resettled refugees depend strongly on where they are initially placed in the host country. Each week, a resettlement agency is allocated a set of refugees by the U.S. government. The agency must place these refugees in its local affiliates while respecting the affiliates' annual capacities. We develop an allocation system that recommends where to place an incoming refugee family to improve total employment success. Our algorithm is based on two-stage stochastic programming and achieves over 98% of the hindsight-optimal employment, compared with under 90% of current greedy-like approaches. This dramatic improvement persists even when we incorporate a vast array of practical features of the refugee resettlement process including inseparable families, batching, and uncertainty with respect to the number of future arrivals. Our algorithm is now part of the Annie™ MOORE optimization software used by a leading American refugee resettlement agency. Funding: This work was supported by the UK Economic and Social Research Council [Grant ES/R007470/1]; the Office of Naval Research [Grant N00014-20-1-2488]; and the National Science Foundation's Division of Civil, Mechanical and Manufacturing Innovation [Grant CMMI-1825348], Division of Computing and Communication Foundations [Grants CCF-1733556 and CCF-2007080], Division of Mathematical Sciences [Grant DMS-1928930], and Division of Information and Intelligent Systems [Grant IIS-2024287]. Supplemental Material: The e-companion is available at https://doi.org/10.1287/opre.2021.0534. [ABSTRACT FROM AUTHOR]

Cybersecurity refers to the actions that are used by people and companies to protect themselves and their information from cyber threats. Different security methods have been proposed for detecting abnormal network behavior, but some effective attacks are still a major concern in the computer community. Many security gaps, such as denial of service, spam, phishing, and other types of attacks, are reported daily, and the number of attacks is growing. Intrusion detection is a security protection method that is used to detect and report any abnormal traffic automatically that may affect network security, such as internal attacks, external attacks, and maloperations. This paper proposes an anomaly intrusion detection system method based on a new RNA encoding method and the ResNet50 Model, where encoding is performed by splitting the training records into different groups. These groups are protocol, service, flag, and digit, and each group is represented by the number of RNA characters that can represent the group's values. The RNA encoding phase converts network traffic records into RNA sequences, allowing for a comprehensive representation of the dataset. The detection model, which uses the ResNet architecture, effectively addresses training challenges and achieves high detection rates for different attack types. The KDD-Cup99 dataset is used for both training and testing. The testing dataset includes new attacks that do not appear in the training dataset, which means that the system can detect new attacks in the future. The efficiency of the suggested anomaly intrusion detection system is determined by calculating the detection rate (DR), false alarm rate (FAR), and accuracy. The achieved DR, FAR, and accuracy are 96.24%, 6.133%, and 95.99%, respectively. The experimental results revealed that the RNA encoding method can improve intrusion detection. [ABSTRACT FROM AUTHOR]

Efficiency Adjusted Deferred Acceptance Rule (EDA) is a promising candidate mechanism for a public school assignment. A potential drawback of EDA is that it could encourage students to game the system since it is not strategy‐proof. However, to successfully strategize, students typically need information that is unlikely to be available to them in practice. We model school choice under incomplete information and show that EDA is regret‐free truth‐telling, which is a weaker incentive property than strategy‐proofness and was introduced by Fernandez (2020). We also show that there is no efficient matching rule that weakly Pareto dominates a stable matching rule and is regret‐free truth‐telling. Note that the original version of EDA by Kesten (2010) weakly Pareto dominates a stable matching rule, but it is not efficient. [ABSTRACT FROM AUTHOR]

In this paper, we study the L(2, 1)-labeling of the Mycielski graph and the iterated Mycielski graph of graphs in general. For a graph G and all t ≥ 1, we give sharp bounds for λ(Mt(G)) the L(2, 1)-labeling number of the t-th iterated Mycielski graph in terms of the number of iterations t, the order n of G, the maximum degree △, and λ(G) the L(2, 1)-labeling number of G. For t = 1, we present necessary and sufficient conditions between the 4-star matching number of the complement graph and λ(M(G)) the L(2, 1)-labeling number of the Mycielski graph of a graph, with some applications to special graphs. For all t ≥ 2, we prove that for any graph G of order n, we have 2t-1(n + 2) - 2 ≤ λ(Mt(G)) ≤ 2t(n + 1) - 2. Thereafter, we characterize the graphs achieving the upper bound 2t(n+1)-2, then by using the Marriage Theorem and Tutte's characterization of graphs with a perfect 2-matching, we characterize all graphs without isolated vertices achieving the lower bound 2t-1(n+2)-2. We determine the L(2, 1)-labeling number for the Mycielski graph and the iterated Mycielski graph of some graph classes. [ABSTRACT FROM AUTHOR]

The modular prediction model of high pressure common rail system was established to study the influence of high‐pressure pipeline integration matching on the fuel injection characteristics of common rail system. The influence of common rail volume on pressure building and pressure fluctuation in common rail tubes was analyzed. The influence of common rail volume on the matching of fuel injection frequency (number of fuel injectors) and fuel supply frequency (number of plunger pumps) was studied by using the control variable method, and the basic optimal solution of the system was obtained. The influence of the common rail structure on the fuel flow characteristics of the system was also studied. The matching relationship between high pressure tubing and common rail system is studied by introducing dimensionless numbers such as length‐diameter ratio of pipeline. The results demonstrate that the increase of the storage space of the accumulator can effectively reduce the fluctuation in the system, so that the injection volume increases slowly and then decreases rapidly, with a slope of −5.70 × 10−3 mm3. The increase of the diameter of the common rail makes the fuel flow characteristics become good first and then bad, and the increase of the length of the common rail can soothe the pressure fluctuations. The increase of the diameter of the link tube (LT) makes the fuel injection volume of the injector increase first and then decrease. The optimal VR solution for the LT is 0.0249 and the optimal ratio of the length to diameter of a pipeline solution is 55.10. The structure of the distribution tube and its matching to the common rail have little effect on the fuel flow characteristics. When the diameter and length of the injection tube are too large, the influence on the injection pressure of the injector is negatively correlated. [ABSTRACT FROM AUTHOR]

This paper presents the results of a numerical study of a planar antenna with a complex form factor. The antenna is based on a combination of two resonators, a disc resonator and a ring resonator. The feeding of the ring resonator is performed using a coplanar structure: pointwise by galvanic contact between the central conductor of the coplanar line and the ring resonator and by distributed electromagnetic coupling of the ring resonator and the aperture of the outer conductor of the coplanar line. The antenna was placed over a metal plane whose geometric dimensions were significantly larger than those of the antenna to exclude the influence of edge diffraction effects. In numerical simulation a complex approach including the method of semi-open resonator and the finite element method (FEM) implemented within the commercial package HFFS was used. The dependences of spectral, energy and polarization characteristics on material constants and frequency parameter have been investigated. It was found that within the framework of single-parameter optimization it is impossible to simultaneously achieve a high level of all important parameters. The values of frequencies of spectral lines in the spectral characteristics of the antenna are found with a relative error not worse than 1200 Hz. Frequency ranges within which there is no degeneration of oscillation types are established. The distributions of surface currents on the metal elements of the antenna, allowing to determine the position of phase centers of excitation, are presented. It is shown that the proposed antenna can provide an acceptable level of matching both at fixed frequencies and in sufficiently wide local frequency bands, reaching 11% with respect to the center frequency of the sub-band. The boundary values of gain coefficients in frequency bands are established. The simulation results allow to predict effective radiation with formation of practically single-lobe radiation pattern and presence of elliptical polarization. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

При изучении иностранного языка студенты неизбежно сталкиваются с межъязыковой интерференцией. Особенно часто интерференция проявляется на грамматическом уровне. Цель данной статьи заключается в том, чтобы обосновать применение основ конструктивной интерференции при создании упражнений, которые будут способствовать усвоению грамматики иностранного языка у студентов. В работе представлены подходы к определению интерференции, в частности, грамматической интерференции, рассмотрены термины, которые обозначают отрицательный и положительный перенос. Приведены примеры упражнений, которые демонстрируют как сравнение грамматических категорий русского и французского языков помогает при обучении иностранному языку. Автор делает вывод, что применение основ конструктивной интерференции способствует эффективному изучению иностранного языка и развитию коммуникативной компетенции студентов.

Copyright of Contemporary Accounting Research is the property of Canadian Academic Accounting Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives/hypothesisTo quantify the effect of the coronavirus disease 2019 (COVID-19) pandemic upon the 2020 to 2021 residency match for Otolaryngology-Head and Neck Surgery (OHNS).Study designRetrospective cohort design.MethodsResidency match outcomes for all applicants to our institution during 2020 to 2021 were collected from the National Residency Matching Program including medical school of origin and matched program. Matches were categorized as to home-program, within-region, or out-of-region and sorted by US geographic region. Matches from the 2020 to 2021 cycle were compared to those from 2019 to 2020, as well as averages and trends from match cycles 2016 to 2020. Statistical analysis included descriptive statistics and chi-square testing.ResultsDuring 2020 to 2021, there were 436 applicants to our single OHNS program. From 2019-2020 to 2020-2021, the match rate decreased significantly for groups studied, including: All applicants (72.0% [268/372] to 64.7% [282/436]; P = .025); all US MD Senior applicants (76.5% [254/332] to 68.9% [262/380]; P = .024); and US MD Seniors specifically without a home program (77.5% [31/40] to 56.4% [22/39]; P = .046). The match rate for US MD Seniors with a home program did not change significantly (76.4% [223/292] to 70.4% [240/341]; P = .09). From 2019-2020 to 2020-2021, the proportion of US MD seniors who matched to home-program increased significantly (22.0% [49/223] to 30.0% [72/240]; P = .05).ConclusionThe COVID-19 pandemic saw high volumes of OHNS applicants with an overall decreased rate of matching compared to previous years. These changes particularly affected applicants without home programs. Home-program matching increased significantly, likely as a consequence of the limitations placed on in-person away experiences including interviews. Laryngoscope, 132:1934-1938, 2022.

Earth observation utilizes multisource satellite data to enhance photogrammetry mapping. This study introduces a novel method to improve the geometric positioning accuracy of large-scale optical satellite imagery by combined adjustment with NASA's Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) laser altimetry data. Although ICESat-2 is known for its high vertical accuracy, its potential to improve horizontal accuracy has been limited due to the difficulty in matching caused by temporal inconsistencies across large survey areas. To address this, our method employs a robust terrain profile elevation sequence similarity matching technique, refined with two-dimensional Gaussian fitting to achieve enhanced position extraction. We also propose a weighted adjustment strategy that uses matching confidence to enhance the precision of the combined adjustments. Large-scale tests across various terrains showed that our approach has significantly reduced horizontal and vertical positioning errors to 4.3 and 1.7 m, respectively, outperforming existing methods.

Water, soil, and heat are strategic supporting elements for human survival and social development. The degree of matching between human-land-water-heat elements directly influences the sustainable development of a region. However, the current evaluation of the matching of human-land-water-heat elements overlooks the influence of elevation factors on the matching results, especially evident in mountainous areas. Taking the Yunnan Plateau with distinctive mountainous features as the research subject, divided into 11 elevation ranges, the Lorenz Gini coefficient, asymmetry coefficient, matching distance, and imbalance index are used to assess the spatial matching and balance of human-land-water-heat elements. A projection tracing model is employed to analyze its water resource carrying capacity. Analyses revealed that the Gini coefficient of monthly precipitation from the 1950s to 2022 on the Yunnan Plateau increases with increasing latitude, whereas the correlation with elevation is notably lower. The asymmetry coefficient increases gradually from west to east with change in longitude. The mismatch of the human–land–water–heat system in regions at different elevations is in the order 1800–2000 m > 2000–2200 m > 1400–1600 m > 800 m > other areas. The matching of the human–land–water–heat system in different wet–dry years and seasons also fluctuates with elevation, resulting in serious seasonal drought and water shortage problems in mountainous areas with elevations of 1200–1600, 1800–2000 m, and >2600 m. The spatial equilibrium of temperature and precipitation in regions of different elevations is best, followed by that of cultivated land, while that of the population is the worst. The Gini coefficients for different water cycle processes of precipitation, surface runoff, and regulating storage capacity for water supply continue to increase. Specifically, the Gini coefficient of industrial water supply is the highest, reaching 0.576, and that of agricultural irrigation is the lowest (0.424). Through artificial regulation of lake and reservoir water, seasonal changes in the demand for agricultural irrigation water are offset to achieve a demand–supply balance and matching of land and water resources. The water resource capacity of different elevation ranges is evenly underloaded. However, the potential of the water resource capacity varies obviously with elevation in the order 2000–2200 m < 1800–2000 m < 1600–8000 m < 1400–1600 m < other areas. It appears that the greater the human–land–water–heat system mismatch, the smaller the regional potential of the water resource capacity. [ABSTRACT FROM AUTHOR]

Computer vision in the structural health monitoring (SHM) field has become popular, especially for processing unmanned aerial vehicle (UAV) data, but still has limitations both in experimental testing and in practical applications. Prior works have focused on UAV challenges and opportunities for the vibration-based SHM of buildings or bridges, but practical and methodological gaps exist specifically for linear infrastructure systems such as pipelines. Since they are critical for the transportation of products and the transmission of energy, a feasibility study of UAV-based SHM for linear infrastructures is essential to ensuring their service continuity through an advanced SHM system. Thus, this study proposes a single UAV for the seismic monitoring and safety assessment of linear infrastructures along with their computer vision-aided procedures. The proposed procedures were implemented in a full-scale shake-table test of a natural gas pipeline assembly. The objectives were to explore the UAV potential for the seismic vibration monitoring of linear infrastructures with the aid of several computer vision algorithms and to investigate the impact of parameter selection for each algorithm on the matching accuracy. The procedure starts by adopting the Maximally Stable Extremal Region (MSER) method to extract covariant regions that remain similar through a certain threshold of image series. The feature of interest is then detected, extracted, and matched using the Speeded-Up Robust Features (SURF) and K-nearest Neighbor (KNN) algorithms. The Maximum Sample Consensus (MSAC) algorithm is applied for model fitting by maximizing the likelihood of the solution. The output of each algorithm is examined for correctness in matching pairs and accuracy, which is a highlight of this procedure, as no studies have ever investigated these properties. The raw data are corrected and scaled to generate displacement data. Finally, a structural safety assessment was performed using several system identification models. These procedures were first validated using an aluminum bar placed on an actuator and tested in three harmonic tests, and then an implementation case study on the pipeline shake-table tests was analyzed. The validation tests show good agreement between the UAV data and reference data. The shake-table test results also generate reasonable seismic performance and assess the pipeline seismic safety, demonstrating the feasibility of the proposed procedure and the prospect of UAV-based SHM for linear infrastructure monitoring. [ABSTRACT FROM AUTHOR]