Today's Large Scale Research Articles

Costly Circuits, Submodular Schedules and Approximate Carathéodory Theorems

Hybrid switching -- in which a high bandwidth circuit switch (optical or wireless) is used in conjunction with a low bandwidth packet switch -- is a promising alternative to interconnect servers in today's large scale data centers. Circuit switches offer a very high link rate, but incur a non-trivial reconfiguration delay which makes their scheduling challenging. In this paper, we demonstrate a lightweight, simple and nearly-optimal scheduling algorithm that trades-off reconfiguration costs with the benefits of reconfiguration that match the traffic demands. Seen alternatively, the algorithm provides a fast and approximate solution towards a constructive version of Caratheodory's Theorem for the Birkhoff polytope. The algorithm also has strong connections to submodular optimization, achieves a performance at least half that of the optimal schedule and strictly outperforms state of the art in a variety of traffic demand settings. These ideas naturally generalize: we see that indirect routing leads to exponential connectivity; this is another phenomenon of the power of multi-hop routing, distinct from the well-known load balancing effects.

Development of distributed measurement and control systems for application in electrical energy systems

In this paper LPC1766 microcontroller based network capable application processor (NCAP) system, is described. This system is intended to be used in modern distributed control and monitoring systems for application in power plants and industry, as well as in modern electricity distribution networks. In order to do that it is necessary to analyze different aspects of the system, like signal processing part or communication requirements. The chosen microcontroller has enough resources to satisfy requirements of an transducer interface module (TIM). Beside the realization of NCAp and TIM controllers it is necessary to develop the necessary measurement modules, in order to realize measurement-control systems. The developed layout could be connected to actuators to the local area network (LAN), as well. If the local LAN is connected to the internet it is possible to monitor and configure measurement modules form the remote site. Having in mind the growing complexity in control systems, it has been a real challenge to detect a diagnose problems in today's large scale distributed systems. Implementation of the proposed module could potentially reduce the time necessary to extract necessary information from the abundant quantity of information that are usually provided by the complex distributed systems.

Preliminary Study of Polymer Removal in 0.25, 0.3, and 0.5 µm Ruthenium Storage Nodes and 0.11 µm, 10.9:1 High-Aspect-Ratio Trenches by Laser-Induced Etching

The demands for new etching technology are increasing because of new materials, such as, ruthenium (Ru), platinum (Pt), and iridium (Ir), that are now being used, and the strict critical dimension (C/D) controls required in today's ultra large scale integrated (ULSI) circuit technology and dynamic random-access memory (DRAM) fabrication lines. Laser etching technology successfully etched organometallic polymers generated after reactive ion etching and ash processing in 0.25, 0.3, and 0.5 µm Ru storage nodes. In this study, the effects of the incident beam profile on the laser-induced etching of the polymers are investigated. Unevenness of the peak energy in the Gaussian beam profile creates unequal etching and heating effects on the polymer removal depending on the irradiating position of the line beam profile on the sample surface. This article discusses for the first time the preliminary results of laser-induced etching with a KrF laser to remove photoresist (PR) and polymer in 0.11 µm deep contact holes with a high-aspect-ratio 10.9:1 trench hole. How deep can the laser etching technology penetrate and strip the PR at a high aspect ratio (A/R) of 10.9:1 and a 0.11 µm hole size? The penetration depth for the PR removal was approximately 1 µm, which is about a 9.1:1 A/R in a 0.11 µm hole with a 1.2-µm-deep trench. Several promising points are discussed on the basis of laser etching in such a high A/R and small 0.11 µm contact hole. Laser-induced etching technology enabled a very uniform penetration depth without any fluctuations, and it also did not show any attack on the edge of the barrier material TiN.

Process Based System Engineering

AbstractThis paper provides a description of a Life Cycle Process Base that combines system engineering techniques and tools for modeling the product to be built with the process for building it. The process template described here provides a means for formally defining the system development process, and then identifying the methods and tools that support the design process. With the adoption and allocation to a specific organization, the template becomes a process. Through simulation and enactment of the process description, an organization is empowered to engineer and evolve the process over time and effectively manage and control the complexity of today's large scale programs.

An overview of modern control strategies for optimizing thermal desalination plants

Water is the essence of life in arid Middle East Countries. The implementation of robust control strategies enhance the efficiency, safety and reliability of the desalination process. A higher degree of automation is essential for today's large scale complex desalination plants. To achieve optimal design and operation of these plants, careful control system design is required. Even when an acceptable design is completed, the question remains as to whether a better design could be found. Conventional techniques provide for analysis and design of the systems which more or less satisfy arbitrary set of performance requirements. However modern control techniques provide an optimum solution based on specified performance index. In this paper an exposition of merits and demerits of conventional and modern control strategies is outlined. A number of optimal procedures that are used for system identification are highlighted. A brief description of Multi-Stage Flash (MSF) desalination process and controls is given. Novel control strategies for a number of important loops of a large MSF desalination plant are presented.

Wasserstoff-Erzeugung und Kreislaufgas-Zerlegung für die Kohleverflüssigung

Hydrogen generation and recycle gas separation for coal liquefaction. Just as 40 years ago, low-temperature processes are now again being considered for recycle gas separation in today's large scale coal liquefaction projects. Hydrogen can be generated by gasification of heavy residues and by steam reforming of ethane. Alternatives for recycle gas separation into hydrogen and gas products are butane and methane absorption or low-temperature condensation processes at high or medium pressure. These processes employ several additional absorption and adsorption steps for gas purification. They are proven on a large technical scale, and fulfill the requirements of environmental legislation.

The Practice of Operations Research in Libraries

The application of operations research methods to library-type problems has a long history which predates the formation of the Operations Research Society. Its practice continues today but much of its emphasis has shifted from concern with the specific problems of a librarian or a library manager to the more general problems of designing large information networks and satisfying the information needs of large classes of users through a variety of services. By moving in these directions, the operations researcher is largely following the course of the application of computers to library-type problems, since much of the motivation on the part of the librarians for the practice of operations research is in preparation for or defense against the relentless onslaught of computer-based automation of information activities. In many respects, it seems that these developments have resulted more in a change of the scale of the problems encountered rather than a change in the substance of the problems, since all of the old concerns and admonitions seem to carry just as much weight now as before. In some respects, they are even more pertinent since the potential rewards and potential risks are much greater in today's large scale applications.