Use of Biological Markers in Risk Assessment1

Measurements of intermediate end points in the carcinogenic process may reduce uncertainty in human risk assessment from bioassay data, by identifying sources of interspecies variation and dose nonlinearity. This paper describes desirable properties of such markers: persistence, predictive power, temporal relevance, and consistency across dose rate and species. We illustrate these properties by evaluating markers for squamous cell nasal carcinoma in rodents exposed to formaldehyde. We also discuss design issues for bioassays that evaluate markers and tumors simultaneously at necropsy.     

Minimum d-blockers and d-transversals in graphs

We consider a set V of elements and an optimization problem on V: the search for a maximum (or minimum) cardinality subset of V verifying a given property ℘. A d-transversal is a subset of V which intersects any optimum solution in at least d elements while a d-blocker is a subset of V whose removal deteriorates the value of an optimum solution by at least d. We present some general characteristics of these problems, we review some situations which have been studied (matchings, s–t paths and s–t cuts in graphs) and we study d-transversals and d-blockers of stable sets or vertex covers in bipartite and in split graphs.     

中国A股公司市盈率、市净率与ROE水平的关系研究

本文利用沪深两市1996年至2002年A股公司的数据,全面系统地研究了ROE水平与市盈率、市净率间的关系,分析了市盈率和市净率作为估值标准的合理性问题.检验结果表明,市净率与ROE水平间是非单调的函数关系,合理地反映了不同ROE水平公司未来业绩、风险和净资产的质量等基本面因素,是理想的估值标准;而市盈率受盈余管理影响很大,不是恰当的估值标准.     

Role of Negative Emotion in Communication about CO2 Risks

This article describes how the effectiveness of risk communication is determined by the interaction between emotional and informative elements. An experiment is described that examined the role of negative emotion in communication about CO₂ risks. This experiment was based on the elaboration likelihood model and the related heuristic systematic model of attitude formation. The results indicated that inducing fear of CO₂ risks leads to systematic processing of information about energy conservation as a risk-reducing strategy. In turn, this results in more favorable attitudes toward energy conservation if strong arguments are provided. Individual differences in concern seem to have similar effects.     

“行/列约束法”在外贸进出口货柜运输业务上的应用

外贸日常进出口业务活动中,我们经常遇到如何利用物质资源条件,求取并实现最理想目标的问题。本文研究了货柜运输业务上三维装箱问题,给出了一个基于管理数学中“行约法 /列约法”的摆放方法。通过和外贸进出口业务常规计算方法比较,降低了创汇成本,增加了经济效益。同时和其它方法比较发展,我们的方法在实际货柜装箱操作上,方便实用。     

Some inverse min-max network problems under weighted l1 and l∞ norms with bound constraints on changes

We consider some inverse min-max (or max-min) network problems. Such an inverse problem is to modify the weights with bound constraints so that a given feasible solution becomes an optimal solution of a min-max (or max-min) network problem, and the deviation of the weights, measured by the weighted l ₁ norm or weighted l _∞ norm, is minimum. In this paper, we present strongly polynomial time algorithms to solve the inverse min-max spanning tree problem and the inverse maximum capacity path problem.     

Quadratic Assignment Problems and M/G/C/C/ State Dependent Network Flows

One of the most notorious network design problems is the Quadratic Assignment Problem (QAP). We develop an heuristic algorithm for QAPs along with an M/G/C/C state dependent queueing model for capturing congestion in the traffic system interconnecting the nodes in the network. Computational results are also presented.     

Line Balancing in Parallel M/M/1 Lines and Loss Systems as Cooperative Games

We consider production and service systems that consist of parallel lines of two types: (i) M/M/1 lines and (ii) lines that have no buffers (loss systems). Each line is assumed to be controlled by a dedicated supervisor. The management measures the effectiveness of the supervisors by the long run expected cost of their line. Unbalanced lines cause congestion and bottlenecks, large variation in output, unnecessary wastes and, ultimately, high operating costs. Thus, the supervisors are expected to join forces and reduce the cost of the whole system by applying line‐balancing techniques, possibly combined with either strategic outsourcing or capacity reduction practices. By solving appropriate mathematical programming formulations, the policy that minimizes the long run expected cost of each of the parallel‐lines system, is identified. The next question to be asked is how to allocate the new total cost of each system among the lines' supervisors so that the cooperation's stability is preserved. For that sake, we associate a cooperative game to each system and we investigate its core. We show that the cooperative games are reducible to market games and therefore they are totally balanced, that is, their core and the core of their subgames are non‐empty. For each game a core cost allocation based on competitive equilibrium prices is identified.     

Use of a case study in sequencing/scheduling research

This paper describes a study of an industrial sequencing/scheduling problem. The study contains the definition of the problem, data requirements and examination of solution technique. Definition of the problem is discussed from the aspect of uniqueness of the specific system. Discussion of data requirements includes availability and accuracy, while examination of solution technique considers limitation of time, computer capacity, etc., as well as the possibility of imbedding available algorithms into the solution procedure. Conclusions are presented relative to the use of the case study approach in sequencing/scheduling research.     

Market Segmentation in Scientific Publications: Research Patterns in American vs European Management Journals1

Ideal science should conform to certain criteria or goals, among them the goals of universalism and commonality. Realization of these goals may be limited, however, through the dividing up of researchers in terms of geographical borders. In this study the general hypothesis is tested that there is a segmentation of the society of management researchers into a North American (US) and a European (E) segment, a segmentation which is furthered by differences in incentive schemes and in paradigms. Four leading management journals from North America and from Europe, respectively, and the 242 articles they contained published in 1993 were selected to represent the different geographical segments. The results provide: support for the existence of two such segments; support for differences in incentive schemes influencing the articles; support for their being paradigm differences between the two segments; and support for a paradigm effect being stronger in US-journals than in E-journals, US-authors are more willing, however, to conform to the E-paradigm than vice versa. We argue for methodological pragmatism in order to reduce the presumed counter-productive effects of paradigmatic rigidity.     

The Role of Trust in the Affective Evaluation of Novel Risks: The Case of CO2 Storage

There is general recognition that trust and affect are closely connected concepts. Usually, affect is modeled as an antecedent of trust. In the present research, we will argue that, particularly in new situations, trust can also evoke affect toward a risky object. Using structural equation modeling, support was found for the hypothesis that trust influences attitudes through this process. In the present study, we analyzed attitudes toward (carbon dioxide) CO₂ storage. The role of affect appears to be moderated by the level of self-relevance. In the case of high self-relevance (storage nearby), people's attitudes appeared to be merely based on affective reactions and trust. This effect is much weaker under low self-relevance (CO₂ storage in general). In such a case, cognitive factors, more particularly beliefs concerning perceived benefits, were also taken into account in attitude formation.     

Managers and Professionals in Business/Industrial Settings

This article reviews some of the research that has been carried out on managerial and executive stress. It indicates that there are a number of potential problem areas: factors intrinsic to the job, role based stress, relationships, career development factors, organizational structure and climate, and the work: family interface. It appears that the area of career development is severely under-researched.     

Supervision in der Ausbildung von Musikerzieher/innen

Supervision in education of music teachers Supervision can make an essential contribution to the teacher training in both phases. The students can consider themselves critically in a censorship free space, and basing on a criticalhermeneutic analysis of their choice of career, they can find their strong and weak points and thus set their main emphasis during their studies. Especially when starting in their job supervision can be helpful to develop their professional identity. Additionally students get to know a model of life-long learning in order to manage 40 years of professional life.     

Zur Integration ehrenamticher Mitarbeiter/innen in Organisationen

The integration of volunteers in organizations On the background of the current changes in the general work conditions, a professional volunteer management in organizations is necessary. The author demonstrates, that in organizations a professional staff with management competences is a precondition. The peculiarities in leading volunteers are explained. The focus of the article are suggestions to a personnel development, in order to instruct and to attend individual employees or larger organizational units for a successful cooperation with volunteers. A special training as well as coaching and organizational development are delineated.     

APPROXIMATIONS FOR THE GI/G/m QUEUE

Queueing models can usefully represent production systems experiencing congestion due to irregular flows, but exact analyses of these queueing models can be difficult. Thus it is natural to seek relatively simple approximations that are suitably accurate for engineering purposes. Here approximations for a basic queueing model are developed and evaluated. The model is the GI/G/m queue, which has m identical servers in parallel, unlimited waiting room, and the first-come first-served queue discipline, with service and interarrival times coming from independent sequences of independent and identically distributed random variables with general distributions. The approximations depend on the general interarrival-time and service-time distributions only through their first two moments. The main focus is on the expected waiting time and the probability of having to wait before beginning service, but approximations are also developed for other congestion measures, including the entire distributions of waiting time, queue-length and number in system. These relatively simple approximations are useful supplements to algorithms for computing the exact values that have been developed in recent years. The simple approximations can serve as starting points for developing approximations for more complicated systems for which exact solutions are not yet available. These approximations are especially useful for incorporating GI/G/m models in larger models, such as queueing networks, wherein the approximations can be components of rapid modeling tools.     

Issues Concerning the Estimation of the TD50

The TD50 (or tumorigenic dose rate 50) is a generally accepted measure of the carcinogenic potency of a chemical in a particular strain of animal. This paper discusses error in the estimation of the TD50 caused by intercurrent mortality and error resulting from consideration of only significant TD50's. Using computer simulations, we found that treatment-related toxicity had only a small effect on estimating the TD50, with errors seldom exceeding 5%. The TD50 is sensitive to changes in tumor lethality with errors ranging to as high as 50%. Many of these errors were significantly different from zero and the results suggest that potency estimation could be improved by basing the estimates upon the tumor incidence rate rather than upon the tumor death rate when an estimate of tumor lethality is obtainable.     

Application of TOC/OPT rules in a medium sized shop

Abstract

Abstract. Theory of constraints (TOC) and optimized production technology (OPT) are frequently presented as the better options for production control systems. Despite this enthusiasm, there is very little literature on how these principles can be implemented in practice without having to resort to the expensive proprietary software. In this paper we present a case study in which the OPT/TOC ideas were implemented without using the software. Management's major concern was reduction of work in process and increased delivery performance. It was decided to test whether the ideas of OPT/TOC were applicable in this environment and more importantly to which extent these two performance measures could be improved. The paper reports on the methodology used to test the OPT/TOC ideas in this shop and presents some early results of improvement, as well as some new problems which arose due to the new approach.     

Die Rolle von Psycholog/innen in den Medien

The role of psychologists in the mediaDiscribing the phenomena of frequently asking journalists the authors are trying to describe the social meaning of role-and functiontaking of the science of psychology in the public discussion. They are following the question whether it could be possible to publish scientific results without banalizing, taking part in voyerism and reprehensible emotion creating.