学科服务 更多>>

关键词： Singularity category   Singular equivalence   Stable category  

摘要： Let R be a right noetherian ring. We introduce the concept of relative singularity category Delta chi(R) of R with respect to a contravariantly finite subcategory chi of mod- R. Along with some finiteness conditions on chi, we prove that Delta chi(R) is triangle equivalent to a subcategory of the homotopy category K-ac(chi) of exact complexes over chi. As an application, a new description of the classical singularity category D-sg(R) is given. The relative singularity categories are applied to lift a stable equivalence between two suitable subcategories of the module categories of two given right noetherian rings to get a singular equivalence between the rings. In different types of rings, including path rings, triangular matrix rings, trivial extension rings and tensor rings, we provide some consequences for their singularity categories.

摘要： Background. Surgery requires a complexity-based ranking system that provides critical information for surgeons to perform strategic operations. However, we still use professional panel systems such as the Risk Adjustment for Congenital Heart Surgery category and the Aristotle Basic Complexity score for this purpose, both of which are subjective. The present study, inspired by more recent development of The Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery mortality scores and categories, applied a Bayesian statistical method to the Japanese nationwide congenital heart registry by estimating inhospital mortality to construct a data-driven, more scientific rating system based on complexity. Methods. The study used a 5-year dataset from the Japan Cardiovascular Surgery Database congenital section to construct a Bayesian estimation model. There were 25,968 operations with 186 cardiovascular procedures. To validate the model, we used an independent 2-year dataset with 14,904 operations. Results. The model-based inhospital mortality estimation provided a complexity rating system that replicated the past study that had proposed a five-category system based on the estimated mortality scores. The C-index with the validation dataset for the mortality score and category was 0.80 and 0.79, respectively. Conclusions. The data-driven approach to complexity rating systems for congenital cardiovascular surgery is recommended, as it has better scientific advantages and more convenient updating features. (C) 2021 by The Society of Thoracic Surgeons

关键词： Decision trees   Integer programming   Machine learning   Binary classification  

摘要： Decision trees have been a very popular class of predictive models for decades due to their interpretability and good performance on categorical features. However, they are not always robust and tend to overfit the data. Additionally, if allowed to grow large, they lose interpretability. In this paper, we present a mixed integer programming formulation to construct optimal decision trees of a prespecified size. We take the special structure of categorical features into account and allow combinatorial decisions (based on subsets of values of features) at each node. Our approach can also handle numerical features via thresholding. We show that very good accuracy can be achieved with small trees using moderately-sized training sets. The optimization problems we solve are tractable with modern solvers.

关键词： auxiliary   Indonesian   crossed control   restructuring   semantic methodology  

摘要： Jeoung (2020) argues that certain predicates in Indonesian are categorially ambiguous between auxiliaries and lexical verbs. Moreover, she claims that the auxiliary reading has been overlooked in analyses of so-called crossed control in Indonesian. As we show in this reply, however, the auxiliary reading is in fact independent of crossed control.

关键词： Measurement while drilling   Drilling parameters   Strata interface   Strata category   Pattern recognition  

摘要： Measurement while drilling is an important part of the intelligent development of coal mines and the development trend of roof formation detection. The main purpose of this paper is to study the best identification method of rock interface and category based on drilling parameters. Firstly, the borehole drilling device was independently developed;Secondly, 4 concrete blocks were poured to simulate the different rock formations;Thirdly, displacement, rotational speed, torque, and sound pressure level data were collected during drilling the concrete blocks, and the original data was processed by the local linear kernel estimation method;Finally, Kmeans clustering and change points detection method, was used to identify the rock formation interface respectively, and BP neural network and support vector machine method was used to identify the rock category respectively. Experimental results show that the local linear kernel estimation method based on exponentially weighted loss function can better reflect the response characteristics of drilling parameters. The change point detection method based on the penetration rate is better for the rock interface prediction (the sum of the two interface errors is 10.25 mm). Besides, with the penetration rate and sound pressure level as input parameters, BP neural network and support vector machine can achieve the operational classification of rock formations. This research is of great significance for understanding the prediction of the interface and category of rock formation in coal mines, which can not only promote safe mining but also reflect efficient coal production.

关键词： COVID-19   vaccination   immunization   hospice   palliative care   ethics  

关键词： warehouse management   order picking   batch‐   routing problem   category constraint   seed algorithms  

摘要： Order picking is the process of retrieving products from the storage locations to meet customer orders, which accounts for more than 55% of the total warehouse cost. The joint order batching and picker routing problem (JOBPRP) is an effective way to improve picking efficiency. Although many warehouses face the physical constraints of products that have impact on the picking sequence, such as weight, size, shape, and fragility, JOBPRP with such physical constraints has not been widely studied in the literature. This paper is inspired by a practical case observed in an online-to-offline grocery store in China, where food products should not be carried under nonfood products in the picking container to maintain food safety, called category constraint. Therefore, JOBPRP with category constraint is studied. The JOBPRP optimization models with and without category constraint are formulated to minimize the total processing time, and the modified seed algorithms, with new seed addition rules and modified near-optimal routing methods are proposed to solve the models. The performance of the proposed algorithms is evaluated in different seed addition rules, routing methods, sort time scenarios, and storage assignment strategies (SASs) in a case study. We found that considering category constraint in JOBPRP can reduce the total processing time, and the modified seed algorithms perform better than the traditional first-come-first-serve benchmark algorithms and the seed algorithms with traditional seed addition rules and S-shape routing method. The SASs where nonfood and food products are separately in fewer number of zones are recommended.

关键词： Finite tensor category   Support varieties   Projective objects   Indecomposable object   Nonsemisimple Hopf algebra  

摘要： We advance support variety theory for finite tensor categories. First we show that the dimension of the support variety of an object equals the rate of growth of a minimal projective resolution as measured by the Frobenius-Perron dimension. Then we show that every conical subvariety of the support variety of the unit object may be realized as the support variety of an object. Finally, we show that the support variety of an indecomposable object is connected. (C) 2021 Elsevier B.V. All rights reserved.

关键词： corporate governance   board composition   board diversity   faultlines   CEO dismissal  

摘要： Research Question/Issue This study investigates the moderating role of social category faultlines in the relationship between firm performance and CEO dismissal. We also examine how two board contingencies-the presence of board evaluation and the number of board committees-affect how social category faultlines moderate the performance-CEO dismissal relationship. Research Findings/Insights Using panel data on Belgian listed firms covering 2006 to 2014, we find that the negative relationship between firm performance and the likelihood of CEO dismissal is significantly weaker when boards experience social category faultlines. Further investigation of board contingencies demonstrates that social category faultlines have a stronger influence on the performance-CEO dismissal relationship when the board does not engage in board evaluation or has greater numbers of board committees. Theoretical/Academic Implications This study builds on the social identity perspective by providing empirical support for social category faultlines within the context of boards of directors. Social category faultlines lead to identity-based subgroups within the board, which reduce directors' identification with the board as a whole, ultimately impacting the board's capability to dismiss a poorly performing CEO. Moreover, our study demonstrates how board contingencies can promote and/or weaken directors' identification with the board, which affects the salience of identity-based subgroups. Practitioner/Policy Implications This study offers insights for practitioners interested in improving board effectiveness. Our evidence implies that decisions concerning the appointment of directors should be based on criteria that take faultlines and subgroups into account. Furthermore, our findings highlight the importance of strengthening the superordinate board identity by implementing initiatives such as board evaluation.

关键词： Paraphilic Disorder   ICD-11   Diagnosis   Sensitivity & Specificity   Dimensions   Categories  

摘要： Background: The diagnosis of paraphilic disorder is a complicated clinical judgment based on the integration of information from multiple dimensions to arrive at a categorical (present/absent) conclusion. The recent update of the guidelines for paraphilic disorders in ICD-11 presents an opportunity to investigate how mental health professionals use the diagnostic guidelines to arrive at a diagnosis which thereby can optimize the guidelines for clinical use. Aim: This study examined clinicians' ability to use the ICD-11 diagnostic guidelines for paraphilic disorders which contain multiple dimensions that must be simultaneously assessed to arrive at a diagnosis. Methods: The study investigated the ability of 1,263 international clinicians to identify the dimensions of paraphilic disorder in the context of written case vignettes that varied on a single dimension only. Outcomes: Participants provided diagnoses for the case vignettes along with dimensional ratings of the degree of presence of five dimensions of paraphilic disorder (arousal, consent, action, distress, and risk). Results: Across a series of analyses, clinicians demonstrated a clear ability to recognize and appropriately integrate the dimensions of paraphilic disorders;however, there was some evidence that clinicians may over-diagnose non-pathological cases. Clinical Translation: Clinicians would likely benefit from targeted training on the ICD-11 definition of paraphilic disorder and should be cautious of over-diagnosing. Strengths and Limitations: This study represents a large international sample of health professionals and is the first to examine clinicians' ability to apply the ICD-11 diagnostic guidelines for paraphilic disorders. Important limitations include not generalizing to all clinicians and acknowledging that results may be different in direct clinical interactions vs written case vignettes. Conclusion: These results indicate that clinicians appear capable of interpreting and implementing the