On a two-server finite queuing system with ordered entry and deterministic arrivals

Consider a two-server, ordered entry, queuing system with heterogeneous servers and finite waiting rooms in front of the servers. Service times are negative exponentially distributed. The arrival process is deterministic. A matrix solution for the steady state probabilities of the number of customers in the system is derived. The overflow probability will be used to formulate the stability condition of a closed-loop conveyor system with two work stations

Forage Research Report, No. 2

Cooperating with the Agricultural Research Service, U.S. Department of Agricultur

The assessment of complex learning outcomes

The Engineering Professors' Council (EPC) produced an output standard in 2000 containing a setof 26 generic statements of what an engineering graduate should have an ability to tackle. In addition, Higher Education (HE) is concerned with the promotion of complex or advanced understanding of subject matter. This leads to complex learning outcomes, which need to be adequately assessed. Changing demands mean changing assessment practices. While good practice is being used in many cases, there is a need to ensure assessment stimulates complex learning. The article seeks to address these issues

Optimizing the performance of a blood analyser: Application of the set partitioning problem

The paper presents some models for optimizing the production rate of an automatic multitest blood analyser. A blood analysis may require one or more tests. The performance of the analyser depends on the test compositions of the analyses and the design of the analyser itself. The design can be changed. The optimal design can be determined by solving a set partitioning problem, given a representative sample of blood analyses

The prescriptive quality of 11 design principles for knowledge productivity

This study explores the learning processes that contribute to knowledge productivity: gradual improvement and radical innovation of an organisation’s operating procedures, products, and services, based on the development and application of new knowledge. The research is based on the assumption that innovation is the result of a series of powerful social learning processes. Previous research revealed a set of eleven design principles that reflect factors that really matter in an innovation process. The study at hand presents how these design principles facilitate the design of an innovation practice. Review workshops and design workshops were used to answer the main research question: How do the design principles facilitate the design of an innovation practice? The data reveals that the design principles do not work as prescriptive rules that in a specific combination, applied to a predefined situation, will result in certain effects. Every design principle offers a new perspective on the innovation practice. This new perspective helps to get new ideas for interventions in the innovation practice. After the design of these interventions it is mainly the facilitator who has an important role in making it a success. If he sees opportunities and is capable, then he can use the interventions to create breakthroughs in the innovation practice

Are speed enforcement cameras more effective than other speed management measures? The impact of speed management schemes on 30mph roads.

This paper presents the results of an evaluation of the impact of various types of speed management schemes on both traffic speeds and accidents. The study controls for general trends in accidents, regression-to-mean effects and migration, separately estimating the accident changes attributable to the impact of the schemes on traffic speed and on traffic volume. It was found that, when judged in absolute terms, all types of speed management scheme have remarkably similar effects on accidents, with an average fall in personal injury accidents of about 1 accident/km/year. In terms of the percentage accident reduction, however, engineering schemes incorporating vertical deflections (such as speed humps or cushions) offer the largest benefits: at 44%, the average reduction in personal injury accidents attributable to such schemes, is twice that at sites where safety cameras were used to control speeds (22%) and they were the only type of scheme to have a significant impact on fatal and serious accidents. Other types of engineering scheme (with a fall of 29% in personal injury accidents) were on average less effective in reducing accidents than schemes with vertical features but more effective than cameras. All types of scheme were generally effective in reducing speeds, with the largest reductions tending to be obtained with vertical deflections and the smallest with other types of engineering schemes

The measurement of air supply volumes and velocities in cleanrooms

Air supply volumes and velocities in cleanrooms are monitored by airflow measuring hoods and anemometers but these measuring methods can be inaccurate if used incorrectly. It is demonstrated in this article that measuring hoods are accurate if the air supply passes evenly out of the hood, as occurs when the air volume is measured from a four-way diffuser or no air supply diffuser. However, when a swirl diffuser was investigated, the measuring hood gave readings more than 50% greater than the true volume. The reasons for the inaccuracy, and methods to correct it were established. Vane anemometers give inaccurate readings at the face of high-efficiency air supply filters, and it was found that the most accurate reading was found about 15 cm from the filter face. The number of readings required across the filter face to obtain an accurate average velocity was investigated, as was a scanning method using overlapping passes

Non destructive examination of composite structures using dielectric examination

Dielectric measurements are widely used in the laboratory to probe the dynamics of molecules, particularly the dynamics of polymer molecules. The dielectric technique exploits the fact that many molecules, although electrically neutral posses an asymmetric distribution of charges which can be approximated to an electric dipole. The (usually thermal) motion of the molecule can be detected by the interaction of this dipole with a time varying electric field. The great advantage of the technique is that no transducers or sensors are required; the direct application of an electric field produces a directly measurable electric response over a frequency range of MHz to GHz. This paper discusses the practical application of dielectric measurements to composite structures and the information that can be obtained on the state of the polymer in polymer composite matrix materials