An artificial neural network based decision support system for solving the buffer allocation problem in reliable production lines

One of the major design problems in the context of manufacturing systems is the well-known Buffer Allocation Problem (BAP). This problem arises from the cost involved in terms of space requirements on the production floor and the need to keep in mind the decoupling impact of buffers in increasing the throughput of the line. Production line designers often need to solve the Buffer Allocation Problem (BAP), but this can be difficult, especially for large production lines, because the task is currently highly time consuming. Designers would be interested in a tool that would rapidly provide the solution to the BAP, even if only a near optimal solution is found, especially when they have to make their decisions at an operational level (e.g. hours). For decisions at a strategic level (e.g. years), such a tool would provide preliminary results that would be useful, before attempting to find the optimal solution with a specific search algorithm.     

EFFECT OF HETEROCYCLIC AMINE ADDITIVES ON THE ABSORPTION RATES OF CARBONYL SULFIDE AND CARBON DIOXIDE IN AQUEOUS METHYLDIETHANOLAMINE SOLUTIONS

Absorption rates of carbonyl sulfide and carbon dioxide into aqueous methyldiethanolamine solutions with and without heterocyclic amine additives were measured in a stirred cell apparatus. All of the heterocyclic amine additives catalyzed COS absorption more strongly than that for CO₂. In instances in which absorption rates were improved by the additives, those with the lowest pK_b's were the most effective, although steric factors also apparently influence reaction kinetics.     

A cascaded sigma-delta pipeline A/D converter with 1.25 MHz signalbandwidth and 89 dB SNR

A low-noise multibit sigma-delta analog-to-digital converter (ADC) architecture suitable for operation at low oversampling ratios is presented. The ADC architecture uses an efficient high-resolution pipelined quantizer while avoiding loop stability degradation caused by pipeline latency. A 16-b implementation of the architecture, fabricated in a 0.6-μm CMOS process, cascades a second-order 5-b sigma-delta modulator with a four-stage 12-b pipelined ADC and operates at a low 8X oversampling ratio. Static and dynamic linearity of the integrated ADC are improved through the use of dynamic element matching techniques and the use of bootstrapped and clock-boosted input switches. The ADC operates at a 20 MHz clock rate and dissipates 550 mW with a 5 V/3 V analog/digital supply. It achieves an SNR of 89 dB over a 1.25-MHz signal bandwidth and a total harmonic distortion (THD) of -98 dB with a 100-kHz input signal     

A Projection System for Real World Three-Dimensional Objects Using Spatial Light Modulators

We discuss a projection system for real world three-dimensional objects using spatial light modulators (SLM). An algorithm to encode the digital holograms of real world objects on to an SLM is presented. We present results from experiments to project holograms of real world holograms using a nematic liquid crystal SLM. We discuss the case when the pixel sizes of the charge-coupled device (CCD) and SLM used for recording the hologram and projection are different.     

WiMAX成就宽带无线梦想

在无线宽带技术的国际竞技舞台上,WiMAX一直是业界最闪烁的新星。从最初的默默无闻和少有人问津,到逐渐地引起运营商们的关注。现在,WiMAX又刮起的一阵无线接入技术的热潮。WiMAX在这样一个进军商用市场的道途中,总是掺拌着各式各样的小插曲……的确,WiMAX这一路走得并不轻松。但是,有哪一颗柔嫩的秧苗不是在经过自然的严峻考验后才成为了参天大树。因此,我们有坚定的理由相信,人类将最终乘着WiMAX翅膀,实现无线宽带的梦想!WiMAX:宽带无线接入的精灵每一项技术都有其各自的“看家本领”和独特定位。WiMAX也不例外。从问世之日起…     

2DEG base hot electron transistors fabricated using MBE and in situion beam lithography

A vertical hot electron transistor incorporating a two-dimensional electron gas (2DEG) base has been fabricated in the GaAs-AlGaAs materials system. The difficulties caused by the need to form selective ohmic contacts to the different conducting layers have been overcome using a combination of in situ focused ion beam (FIB) isolation and molecular beam epitaxial (MBE) regrowth. This has allowed a high yield of working devices to be achieved with a typical common emitter current gain of h_FE=6 at low temperatures     

Providing incentives in providerless networks

This paper explores the extension of a model for the operation of an ad hoc mobile network to more general providerless networks, such as peer-to-peer systems. The model incorporates incentives for users to act as transit nodes on multi-hop paths and to be rewarded with their own ability to send traffic. The paper explores some of the trust questions that arise in this problem space and conjectures that the very structure of a peer organisation may have some hidden benefits for trust re-enforcement, that have not been previously explored (to our knowledge).