Experimental Design of Bioassays for Screening and Low Dose Extrapolation

Relatively high doses of chemicals generally are employed in animal bioassays to detect potential carcinogens with relatively small numbers of animals. The problem investigated here is the development of experimental designs which are effective for high to low dose extrapolation for tumor incidence as well as for screening (detecting) carcinogens. Several experimental designs are compared over a wide range of different dose response curves. Linear extrapolation is used below the experimental data range to establish an upper bound on carcinogenic risk at low doses. The goal is to find experimental designs which minimize the upper bound on low dose risk estimates (i.e., maximize the allowable dose for a given level of risk). The maximum tolerated dose (MTD) is employed for screening purposes. Among the designs investigated, experiments with doses at the MTD, 1/2 MTD, 1/4 MTD, and controls generally provide relatively good data for low dose extrapolation with relatively good power for detecting carcinogens. For this design, equal numbers of animals per dose level perform as well as unequal allocations.     

How European PR practitioners handle digital and social media

The European Communication Monitor (ECM) 2010 showed that digital communication and social media have grown in importance in the media mix of European organizations. Both new media types are positively correlated to the perceived impact of public relations (PR) in the organization. Specifically social networks and online videos are considered the most important social media tools. Also European practitioners expect that the content of communication will become more important as and when the use of social media further increases. The consequence that everyone within the organization is able to spread information is perceived as the most problematic aspect of social media. A potential problem is that only about one third of the European organizations have implemented social media policies with communication consultancies leading the way. Communication consultants consider social media significantly more important than practitioners working in organizations.     

User acceptance of cooperative maneuver-based driving--a summary of three studies

Modern cars offer drivers support with the help of a number of driver assistance systems. Those systems aim to relieve drivers through assumption of sub parts of the driving task (e.g. in case of an Adaptive Cruise Control by regulation of vehicle speed and time gap to preceding vehicle). Today, systems are controlled and monitored separately which leads to efforts to combine the functionality of all systems in an overlying assistance for drivers. The approach of the University of Technology Darmstadt is called Conduct-by-Wire and can be seen as a cooperative maneuver-based driving paradigm, where the driver gives maneuver command to the systems which are automatically executed. This paper summarizes the results of three studies which investigated the user acceptance of this driving paradigm. Overall, it can be said that the acceptance of the system depends on personal traits of the driver and on the driving situation. Almost all participants are willing to use Conduct-by- Wire for routine tasks such as commuting, which makes the systems interesting for company cars. Still, there remain a number of drivers who are not willing to use such a highly automated system at all.     

Development of a knowledge management system for complex domains

Deutsche Flugsicherung GmbH, the German Air Navigation Service Provider, follows a systematic approach, called HERA, for investigating incidents. The HERA analysis shows a distinctive occurrence of incidents in German air traffic control in which the visual perception of information plays a key role. The reasons can be partially traced back to workstation design, where basic ergonomic rules and principles are not sufficiently followed by the designers in some cases. In cooperation with the Institute of Ergonomics in Darmstadt the DFS investigated possible approaches that may support designers to implement ergonomic systems. None of the currently available tools were found to be able to meet the identified user requirements holistically. Therefore it was suggested to develop an enhanced software tool called Design Process Guide. The name Design Process Guide indicates that this tool exceeds the classic functions of currently available Knowledge Management Systems. It offers "design element" based access, shows processual and content related topics, and shows the implications of certain design decisions. Furthermore, it serves as documentation, detailing why a designer made to a decision under a particular set of conditions.     

Application of the user-centred design process according ISO 9241-210 in air traffic control

Designing a usable human machine interface for air traffic control is challenging and should follow approved methods. The ISO 9241-210 standard promises high usability of products by integrating future users and following an iterative process. This contribution describes the proceeding and first results of the analysis and application of ISO 9241-210 to develop a planning tool for air traffic controllers.     

OPTIMAL SAFETY-STOCK INVESTMENT THROUGH SUBJECTIVE EVALUATION OF STOCKOUT COSTS

This paper solves the problem of setting safety stocks by combining a subjective evaluation of the stockout-cost function with the usual holding-cost function. The technique given in this paper for estimating a decision maker's (DM's) disvalue function for stockouts is robust in terms of the shapes permissible for this function and allows for uncertainty on the part of the DM in expressing his/her trade-offs. The estimation technique could be applied to situations other than the safety-stock problem. We provide an optimization routine for the safety-stock problem which is designed to operate in conjunction with the estimation technique. Safety-stock levels are arrived at iteratively.     

Social Mobility,Equity and the Politics of Recruitment

Much reliance has been placed on increased equity as a way of improving social mobility but the evidence base for this view, for example in Britain, looks less and less convincing. Part of the attraction of equity was that it was believed to promote efficiency through the refinement of meritocracy. Sociological theory now suggests that the equation of equity with efficiency may have prevented reforms which would have improved social mobility. This theory fills a gap in the human resource management (HRM) literature to show that it is far from obvious what managers should do to increase organisational efficiency when they make recruitment decisions. Instead of recruiting for efficiency, their decisions are shaped by the politics of recruitment both inside organisations, affecting management decision‐making particularly, and outside organisations amongst legislators and pressure groups (for example). This politics has shaped the way equity figures in recruitment, it has, for the most part, only figured to the extent that it was believed to serve efficiency, yet what counted for efficiency was itself a political product. When it is hide‐bound in this way it is small wonder that insufficient progress has been made in improving social mobility, in Britain and elsewhere, by increasing equity.     

Portfolio optimization: New capabilities and future methods

Summary  This paper addresses the problem of portfolio selection in finance. In many cases, currently available software to compute the efficient frontier runs into difficulty in problems with more than about 600 securities. To proceed beyond this size, it is often necessary to modify the problem in which case there is typically a loss of information. In this paper, we discuss a computer capability that can exactly compute mean-variance efficient frontiers of problems with up to 2,000 securities in very reasonable time (even if a problem’s covariance matrix is 100% dense). The paper also discusses an augmentation to the theory of portfolio selection that allows multiple objectives (such as dividends, liquidity, social responsibility, amount invested in R&D, and so forth) to be incorporated into the portfolio selection process. In such problems, the efficient set is no longer a “frontier,” but is now best described as a “surface” with the interesting property that it is composed of platelets (like on the back of a turtle). Moreover, the computer capability that can compute the exact efficient frontier of a mean-variance problem with up to 2,000 securities also has, after additional coding, the ability to compute exactly all platelets of the efficient surface of a tri-criterion portfolio problem with up to 400 securities.

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Zusammenfassung  In dieser Arbeit stellen wir einen leistungsf?higen Rechenalgorithmus vor, um den effizienten Rand (die nichtdominierten Alternativen) von Portfolio-Auswahlproblemen in der Finanzierung zu bestimmen. Wir bezeichnen den Berechnungsalgorithmus, der in Java programmiert ist, mit MPQ (multi-parametric quadratic programming). MPQ weist gegenüber bisherigen Berechnungsverfahren eine Reihe von Vorteilen auf: Es kann für umfangreiche Anwendungsf?lle genutzt werden, ist durch passable Rechenzeiten charakterisiert und kann die Menge effizienter Alternativen in einem Bruchteil bisher üblicher Rechenzeiten bestimmen.