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关键词： Data mining   Distance-based clustering   Pattern mining   Maximal frequent itemsets   Cluster center initialization   Categorical data  

摘要： The performance of a partitional clustering algorithm is influenced by the initial random choice of cluster centers. Different runs of the clustering algorithm on the same data set often yield different results. This paper addresses that challenge by proposing an algorithm namedk-PbC, which takes advantage of non-random initialization from the view of pattern mining to improve clustering quality. Specifically,k-PbC first performs a maximal frequent itemset mining approach to find a set of initial clusters. It then uses a kernel-based method to form cluster centers and an information-theoretic based dissimilarity measure to estimate the distance between cluster centers and data objects. An extensive experimental study was performed on various real categorical data sets to draw a comparison betweenk-PbC and state-of-the-art categorical clustering algorithms in terms of clustering quality. Comparative results have revealed that the proposed initialization method can enhance clustering results andk-PbC outperforms compared algorithms for both internal and external validation metrics. k-PbC algorithm for categorical data clustering

关键词： TSH levels   Bethesda IV   Malignancy   Nodular thyroid disease  

摘要： Fine needle aspiration biopsy does not permit to distinguish between benign and malignant follicular thyroid lesions (category IV in the Bethesda Cytopathology System). Some reports have suggested an association between increased serum TSH levels and thyroid cancer, so the aim of this study was to investigate the association between TSH levels and malignancy in patients with follicular thyroid nodules. Therefore, we conducted a retrospective study of all subjects who underwent surgical treatment for Bethesda IV thyroid nodules in a single center (years 2012-2017). A total of 127 patients were analyzed, and malignancy was present in 38.6% of the patients. Using ROC analysis, the best TSH cut-off point to differentiate benign from malignant disease was 2.1 mU/l and the age cut-off with better sensitivity and specificity was 47 years. The proportion of subjects with TSH >= 2.1 mU/l was greater among subjects with cancer than in those with benign diseases (65.3 vs 44.9%, P = 0.029). The concurrence of both cut-off points (TSH >= 2.1 mU/l and age >= 47 years) showed a higher diagnostic accuracy than either of the two variables separately. Therefore, the present study supports an association between serum concentrations of TSH and risk of malignancy among subjects with Bethesda IV thyroid nodules. TSH levels could modify the diagnostic and therapeutic approach of patients with Bethesda IV nodules.

关键词： Commerce  

摘要： When developing new products, it is important to understand not only the category, but also the characteristics of existing products in that category. It is common to analyze white spaces and generate ideas based on the markets in one's home country;but it is less common to look to other countries for inspiration for new product ideas. Differences in culture and practice may create difficulties for researchers. The objective of this case study was to determine and address the methodological challenges of conducting a product category assessment in an unfamiliar country. This was accomplished by exploring the snack food markets in Kyoto, Japan;and collecting snack products to generate new concepts for future snack food innovation projects. Fifteen sensory experts from Kansas State University traveled to Kyoto, Japan to understand better the regional snack food market. The researchers targeted shops and markets in search of various types of snacks. The group tasted a subset of the snacks and held discussions on product sensory attributes, and any challenges in obtaining and understanding the snacks. Issues included payment, data collection, product selection, evaluation space, language barriers, and transportation. Real-time problem solving and group discussion led to solutions to overcome such challenges. Practical Applications This paper provides a set of considerations for better understanding a product category in an unfamiliar country. It highlights issues and potential solutions for researchers who want to conduct such research.

关键词： Monoid algebras   Quiver presentation   Locally trivial categories  

摘要： In this paper we study the representation theory of three monoids of partial functions on ann-set. The monoid of all order-preserving functions (i.e., functions satisfyingf(x) <= f(y) ifx <= y) the monoid of all order-decreasing functions (i.e. functions satisfyingf(x) <= x) and their intersection (also known as the partial Catalan monoid). We use an isomorphism between the algebras of these monoids and the algebras of some corresponding locally trivial categories. We obtain an explicit description of a quiver presentation for each algebra. Moreover, we describe other invariants such as the Cartan matrix and the Loewy length.

关键词： Abstraction   Abstract concepts   Concrete concepts   Generic categories   Specific categories  

摘要： Conceptual concreteness and categorical specificity are two continuous variables that allow distinguishing, for example, justice (low concreteness) from banana (high concreteness) and furniture (low specificity) from rocking chair (high specificity). The relation between these two variables is unclear, with some scholars suggesting that they might be highly correlated. In this study, we operationalize both variables and conduct a series of analyses on a sample of > 13,000 nouns, to investigate the relationship between them. Concreteness is operationalized by means of concreteness ratings, and specificity is operationalized as the relative position of the words in the WordNet taxonomy, which proxies this variable in the hypernym semantic relation. Findings from our studies show only a moderate correlation between concreteness and specificity. Moreover, the intersection of the two variables generates four groups of words that seem to denote qualitatively different types of concepts, which are, respectively, highly specific and highly concrete (typical concrete concepts denoting individual nouns), highly specific and highly abstract (among them many words denoting human-born creation and concepts within the social reality domains), highly generic and highly concrete (among which many mass nouns, or uncountable nouns), and highly generic and highly abstract (typical abstract concepts which are likely to be loaded with affective information, as suggested by previous literature). These results suggest that future studies should consider concreteness and specificity as two distinct dimensions of the general phenomenon called abstraction.

关键词： Breast cancer   High axillary nodal burden   Tumor characteristics   Ultrasound  

摘要： The purpose of this study was to determine whether incorporation of the ultrasound (US) features of the primary tumor and axillary lymph node (ALN) could improve the prediction of high axillary nodal burden (HNB) and, thus, avoid unnecessary sentinel lymph node biopsy (SLNB). A total of 347 patients with Breast Imaging Reporting and Data System US category 4 or 5 breast cancer lesions were included. Their pre-operative US features and post-operative pathologic results were collected. The patients were then divided into the following groups based on surgical histology: limited nodal burden (LNB: 0-2 LNs involved) and heavy nodal burden (HNB: >= 3 metastatic LNs). Univariate and multivariate logistic regression analyses were conducted to determine the most valuable variables for HNB prediction. Receiver operating characteristic curves were obtained to assess their values. We found that a non-circumscribed margin, cortical thickness (>= 3 mm) and number (>= 3) of suspicious ALNs are indicators for HNB prediction. The false-negative rate (FNR) in model 1 (cortical thickness + number of suspicious ALNs) was 15.5% versus 3.4% in model 2 (non-circumscribed margin + cortical thickness + number of suspicious ALNs). Our results indicate that combining the US features of the primary tumor and ALNs can reduce the FNR during HNB prediction. (E-mail addresses: mzong@*** lcy_njmu@163. com) (c) 2020 World Federation for Ultrasound in Medicine & Biology. All rights reserved.

关键词： Extriangulated categories   Cluster tilting subcategories   Abelian categories  

摘要： For a triangulated category T, if C is a cluster-tilting subcategory of T, then the factor category T/C is an abelian category. Under certain conditions, the converse also holds. This is a very important result of cluster-tilting theory, due to Koenig-Zhu and Beligiannis. Now let B be a suitable extriangulated category, which is a simultaneous generalization of triangulated categories and exact categories. We introduce the notion of pre-cluster tilting subcategory C of B, which is a generalization of cluster tilting subcategory. We show that C is cluster tilting if and only if the factor category B/C is abelian. Our result generalizes the related results on a triangulated category and is new for an exact category case.

摘要： The B-p-algebras are a family of vertex operator algebras parameterized by p is an element of Z >= 2. They are important examples of logarithmic CFTs and appear as chiral algebras of type (A1,A2p-3) Argyres-Douglas theories. The first member of this series, the B2-algebra, are the well-known symplectic bosons also often called the beta gamma vertex operator algebra. We study categories related to the B-p vertex operator algebras using their conjectural relation to unrolled restricted quantum groups of sl2. These categories are braided, rigid and non semi-simple tensor categories. We list their simple and projective objects, their tensor products and their Hopf links. The latter are succesfully compared to modular data of characters thus confirming a proposed Verlinde formula of David Ridout and the second author.

关键词： Construction industry   Construction automation   Blockchain   Distributed Ledger Technology (DLT)   Smart contracts  

摘要： Blockchain and other forms of Distributed Ledger Technology (DLT) provide an opportunity to integrate digital information, management, and contracts to increase trust and collaboration within the construction industry. DLT enables direct peer-to-peer transactions of value across a distributed network by providing an immutable and transparent record of these transactions. Furthermore, there is potential for business process optimization and automation on the transaction level through the use of smart contracts, which are code protocols deployed on supported DLT systems. However, DLT research in the construction industry remains at a theoretical level;there have been few implementation case studies to date. One potential reason for this is a knowledge gap between use-case ideas and the DLT technical system implementation. This paper aims to reduce this gap by (1) reviewing and categorizing proposed DLT use cases in construction literature, (2) providing an overview of DLT and its design options, (3) proposing an integrated framework to match DLT design options with desired characteristics of a use case, and (4) analysing the use cases using the new framework. Together, the use case categories and proposed decision framework can guide future implementers toward more connected and structured thinking between the technological properties of DLT and use cases in construction.