Distance graphs on R n with 1-norm

Suppose S is a subset of a metric space X with metric d. For each subset D⊆{d(x,y):x,y∈S,x≠y}, the distance graph G(S,D) is the graph with vertex set S and edge set E(S,D)={xy:x,y∈S,d(x,y)∈D}. The current paper studies distance graphs on the n-space R ₁ ⁿ with 1-norm. In particular, most attention is paid to the subset Z ₁ ⁿ of all lattice points of R ₁ ⁿ . The results obtained include the degrees of vertices, components, and chromatic numbers of these graphs. Dedicated to Professor Frank K. Hwang on the occasion of his 65th birthday. Supported in part by the National Science Council under grant NSC-94-2115-M-002-015. Taida Institue for Mathematical Sciences, National Taiwan University, Taipei 10617, Taiwan. National Center for Theoretical Sciences, Taipei Office.     

"分"何以能"合":加拿大多元文化管理的内在机制分析

加拿大是世界上移民国家中最早建立多元文化主义政策的国家.自从这一政策问世以来,学界对多元文化主义产生了不同的认识,褒贬不一.尤其其中有一种观点认为,多元文化主义导致文化上的断裂,容易使国家分裂.本文从多元文化管理的角度,从社会一体化、法治建设、民主政治以及福利国家四个方面对加拿大这一政策的实践及其效果进行了分析;并以此为基础,对学界中存在的观点进行了回应.     

素质教育、创新教育与人才培养计划

素质教育、创新教育的教育思想如何体现,十几年来在高等教育的教育改革与实践中被研究、深化.人才培养计划作为人才培养的指导性文件,是人才培养的指南.如何能够较好体现素质教育、创新教育思想,是将人才培养计划落在实处的重要方面.     

中国少儿期刊的读者状况分析

少儿期刊拥有较为庞大而稳定的读者群,有相当大的市场发展空间。少儿读者受经济、教育、文化、新媒体等因素的影响,有其特殊性,且不同年龄段有不同的阅读心理特征与阅读水平。少儿期刊要符合、适应这种变化,不断满足读者的新需求。     

试论声乐演唱中的气息运用

文章从生理解剖学的角度来解释正确呼吸时人体相应器官的配合运作过程 ,把客观理论及前人的经验方法与演唱者的实际体验相结合 ,进一步阐述应当如何控制使用自如的呼吸唱出美好的声音     

文官政治·书卷风流·人文气象--宋代文学存在的社会文化背景分析

有宋一代 ,文化大昌 ,文学也出现繁荣气象 ,这同宋代的社会环境及文化背景密切相关。宋型文化 ,有着向内收敛及注重人文涵养的倾向 ,这也深深影响了宋代文学及文学思想。简言之 ,宋代社会的基础是文官政治 ,内在精神是注重品性涵养 ,外在的表现是书卷风流。它们三位一体 ,构成了宋人所处的富于浓郁人文气息的氛围 ,其审美情趣也从外在的羁旅漫游、征戍迁谪、行旅离别 ,逐渐转向丰富多彩的心智活动 ,于是构成宋代文学及文学思想中博大精深的人文气象     

我国森林资源境外开发对策研究

森林资源境外开发是森林资源三大供给体系的重要组成部分,是指运用相关理论,采取一定的方式与手段与本国以外的国家、地区、企业发生的一些具体的林业经济关系。文章分析了我国林业利用国外森林资源战略目标及实现条件,研究并提出一系列措施。     

分析师利益与投资建议的信息含量

 内容提要:本文分析了证券分析师的利益和我国证券分析师投资建议的信息含量。本文发现，证券分析师投资建议大多为“买入”或“中性”建议，而“卖出”建议却很少。通过对投资建议发布日附近股票超额回报率和超常交易量的研究，本文发现“买入”、“卖出”建议分别会引起股价的永久性上涨和下跌，而“中性”建议不会对股价产生显著影响。此外，被建议“买入”和“卖出”的股票的交易量也会明显地增加，特别是在建议发布的当日。这些现象说明，投资者认为分析师的建议包含了有价值的信息，因而相应地调整了对未来收益的预期以及当前最优的持股数量。股票交易的活跃给证券公司带来了佣金收入，作为对他们向市场传递有价值信息的回报。     

网络语境下民族院校校报发展的创新性思考

作为高校思想政治教育和新闻宣传工作的重要阵地,高校校报有其重要的育人功能和明确的舆论导向作用.在互联网迅速发展的新时期,民族院校校报未来发展面临很多挑战.但只要与时俱进,深入思考,锐意创新,在这种崭新的网络语境下,民族院校校报还是大有可为的.占领宣传教育制高点,从内容和形式等方面进行改革创新,必将带来校报的可持续发展.     

Establishing decision tree-based short-term default credit risk assessment models

ABSTRACT

Traditional credit risk assessment models do not consider the time factor; they only think of whether a customer will default, but not the when to default. The result cannot provide a manager to make the profit-maximum decision. Actually, even if a customer defaults, the financial institution still can gain profit in some conditions. Nowadays, most research applied the Cox proportional hazards model into their credit scoring models, predicting the time when a customer is most likely to default, to solve the credit risk assessment problem. However, in order to fully utilize the fully dynamic capability of the Cox proportional hazards model, time-varying macroeconomic variables are required which involve more advanced data collection. Since short-term default cases are the ones that bring a great loss for a financial institution, instead of predicting when a loan will default, a loan manager is more interested in identifying those applications which may default within a short period of time when approving loan applications. This paper proposes a decision tree-based short-term default credit risk assessment model to assess the credit risk. The goal is to use the decision tree to filter the short-term default to produce a highly accurate model that could distinguish default lending. This paper integrates bootstrap aggregating (Bagging) with a synthetic minority over-sampling technique (SMOTE) into the credit risk model to improve the decision tree stability and its performance on unbalanced data. Finally, a real case of small and medium enterprise loan data that has been drawn from a local financial institution located in Taiwan is presented to further illustrate the proposed approach. After comparing the result that was obtained from the proposed approach with the logistic regression and Cox proportional hazards models, it was found that the classifying recall rate and precision rate of the proposed model was obviously superior to the logistic regression and Cox proportional hazards models.