Development of a Position Sensitive Neutron Detector with High Efficiency and Energy Resolution for Use at High-Flux Beam Sources

We are developing a high-efficiency neutron detector with 1 cm position resolution and coarse energy resolution for use at high-flux neutron source facilities currently proposed or under construction. The detector concept integrates a segmented ³He ionization chamber with the position sensitive, charged particle collection methods of a MicroMegas detector. Neutron absorption on the helium produces protons and tritons that ionize the fill gas. The charge is amplified in the field region around a wire mesh and subsequently detected in current mode by wire strips mounted on a substrate. One module consisting of a high-voltage plate, a field-shaping high-voltage plate, a grid and wire strips defines a detection region. For 100 % efficiency, detector modules are consecutively placed along the beam axis. Analysis over several regions with alternating wire strip orientation provides a two-dimensional beam profile. By using ³He, a 1/v absorption gas, each axial region captures neutrons of a different energy range, providing an energy-sensitive detection scheme especially useful at continuous beam sources.     

Controlled production planning for Just-In-Time short-run suppliers

In the face of growing global competitiveness it is necessary for US manufacturers to manage their limited resources in quite the opposite manner of the way they have been managed in the past. Just-In-Time (JIT) is a practice which, by eliminating waste, improving quality, and increasing productivity, has helped manufacturers meet the competition. The core requirement of JIT in practice, however, is the timely delivery of quality products. This requirement has exerted significant economic pressure on short-run JIT suppliers that provide low-volume, diversified products. This paper presents a means by which JIT methods and Statistical Process Control may be applied jointly to short run production in an environment with demand uncertainties. The purpose of this study is threefold: (1) to examine the cost structure of short-run production, (2) to propose the application of controlled production planning, and (3) to discuss the effect of controlled production planning on the cost structure of JIT suppliers. This study examines the economic impact of JIT demands on the cost structure of short-run production and proposes Controlled Production Planning (CPP) for generating signals for delivery failures or overproduction plans. Establishing CPP minimizes short-term production plan fluctuations, reduces inventory based on the market situation, and reduces the total cost of production. Using a computer simulation we demonstrate that CPP is a viable method for achieving these inventory and production goals. Based on this proposal, three inventory strategies are recommended to short-run suppliers in order to minimize their operating costs under different business conditions. The first strategy uses CPP to determine an inventory cap that requires the maintenance of an average level of stock as a lower control limit to cope with short-run demand fluctuation. This strategy is applicable to a business condition with high product quality and low flexibility to respond to fluctuating demands. The second strategy is zero inventory exercised by sole suppliers offering standard products. The third strategy is a flexible production system combined with zero inventory, which is applicable to suppliers facing strong competition without the market position to absorb their production surplus.     

Transporting QoS adaptive flows

Distributed audio and video applications need to adapt to fluctuations in delivered quality of service (QoS). By trading off temporal and spatial quality to available bandwidth, or manipulating the playout time of continuous media in response to variation in delay, audio and video flows can be made to adapt to fluctuating QoS with minimal perceptual distortion. In this paper, we extend our previous work on a QoS Architecture (QoS-A) by populating the QoS management planes of our architecture with a framework for the control and management of multilayer coded flows operating in heterogeneous multimedia networking environments. Two key techniques are proposed: i) an end-to-end rate-shaping scheme which adapts the rate of MPEG-coded flows to the available network resources while minimizing the distortion observed at the receiver; and ii) an adaptive network service, which offers “hard” guarantees to the base layer of multilayer coded flows and “fairness” guarantees to the enhancement layers based on a bandwidth allocation technique called Weighted Fair Sharing.     

The CADE-14 ATP System Competition

This paper documents the design, competing systems, results, and conclusions of the CADE-14 ATP System Competition (CASC-14).     

The application of IT in organisations: Some trends and issues

Abstract

This paper describes some trends and issues in the application of information technology in organisations. Technology trends are outlined in the areas of computing power, telecommunications, networking, software and standards. Some trends in the applications of IT are described with respect to developments in information systems and office automation. Some differences in the likely role of IT in the industrialised and developing countries are discussed. The second half of the paper deals with issues in the management of IT applications in organisations, and issues are identified as being political, organisational and social in nature in addition to technical. A social systems framework is proposed for the analysis of these issues. Some specific IT issues are then discussed involving alternative stakeholder perspectives, the analysis of decision making processes, the process of consultation and communication and the organisational impacts of IT applications.     

Designing emergent cooperation: a pursuit–evasion game case study

This research concerns a comparison of two neuroevolution approaches for the design of cooperative behavior in a group of simulated mobile robots. The first approach, termed single pool (SP), was characterized by robot neural controllers that were derived from a single genotype. The second approach, termed multiple pools (MP), was characterized by robot neural controllers that were derived from many different genotypes. The application domain implemented a pursuit–evasion game in which teams of robots of various sizes, termed predators, collectively worked to capture (immobilize) other robots, termed prey. The MP and SP approaches were tested, with and without lifetime learning, for the design of cooperative prey capture behavior within teams of predators. Results indicated that the MP approach was superior to the SP approach in terms of measures defined for prey-capture performance. Specifically, the MP approach facilitated behavioral specializations in the predator team facilitating emergent cooperative prey capture strategies that proved effective for the various team sizes tested.