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1405

Winning post [mail systems]

Businesses that take their mail for granted can end up wasting money as well as opportunities. Mike Stecyk, VP of marketing and lines of business at Pitney Bowes, suggests strategies for making more of a great opportunity

1091

Car-caravan snaking. 1. The influence of pintle pin friction

A brief review of knowledge of car-caravan snaking is carried out. Against the background described, a fairly detailed mathematical model of a contemporary car-trailer system is constructed and a baseline set of parameter values is given. In reduced form, the model is shown to give results in accordance with literature. The properties of the baseline combination are explored using both linear and non-linear versions of the model. The influences of damping at the pintle joint and of several other design parameters on the stability of the linear system in the neighbourhood of the critical snaking speed are calculated and discussed. Coulomb friction damping at the pintle pin is then included and simulations are used to indicate the consequent amplitude-dependent behaviour. The friction damping, especially when its level has to be chosen by the user, is shown to give dangerous characteristics, despite having some capacity for stabilization of the snaking motions. It is concluded that pintle pin friction damping does not represent a satisfactory solution to the snaking problem. The paper sets the scene for the development of an improved solution

1440

Application of ultrasonic sensors in the process industry

Continuous process monitoring in gaseous, liquid or molten media is a fundamental requirement for process control. Besides temperature and pressure other process parameters such as level, flow, concentration and conversion are of special interest. More qualified information obtained from new or better sensors can significantly enhance the process quality and thereby product properties. Ultrasonic sensors or sensor systems can contribute to this development. The state of the art of ultrasonic sensors and their advantages and disadvantages will be discussed. Commercial examples will be presented. Among others, applications in the food, chemical and pharmaceutical industries are described. Possibilities and limitations of ultrasonic process sensors are discussed

856

People who make a difference: mentors and role models

The literature of gender issues in computing steadfastly and uniformly has advocated the use of mentors and role models (M&RM) for recruiting and retaining women in computer science. This paper, therefore, accepts the results of research studies and avoids reiterating details of the projects but offers instead a practical guide for using M&RM to recruit and retain women in computer science. The guide provides pragmatic advice, describing several different facets of the M&RM concept

813

On generalized Gaussian quadratures for exponentials and their applications

We introduce new families of Gaussian-type quadratures for weighted integrals of exponential functions and consider their applications to integration and interpolation of bandlimited functions. We use a generalization of a representation theorem due to Caratheodory to derive these quadratures. For each positive measure, the quadratures are parameterized by eigenvalues of the Toeplitz matrix constructed from the trigonometric moments of the measure. For a given accuracy epsilon , selecting an eigenvalue close to epsilon yields an approximate quadrature with that accuracy. To compute its weights and nodes, we present a new fast algorithm. These new quadratures can be used to approximate and integrate bandlimited functions, such as prolate spheroidal wave functions, and essentially bandlimited functions, such as Bessel functions. We also develop, for a given precision, an interpolating basis for bandlimited functions on an interval

738

Playing for time [3G networks]

The delays in rolling out 3G networks across Europe should not always be seen with a negative slant

1328

Tablet PCs on the way [publishing markets]

Previews of hardware and software look promising for publishing markets

1155

A leaf sequencing algorithm to enlarge treatment field length in IMRT

With MLC-based IMRT, the maximum usable field size is often smaller than the maximum field size for conventional treatments. This is due to the constraints of the overtravel distances of MLC leaves and/or jaws. Using a new leaf sequencing algorithm, the usable IMRT field length (perpendicular to the MLC motion) can be mostly made equal to the full length of the MLC field without violating the upper jaw overtravel limit. For any given intensity pattern, a criterion was proposed to assess whether an intensity pattern can be delivered without violation of the jaw position constraints. If the criterion is met, the new algorithm will consider the jaw position constraints during the segmentation for the step and shoot delivery method. The strategy employed by the algorithm is to connect the intensity elements outside the jaw overtravel limits with those inside the jaw overtravel limits. Several methods were used to establish these connections during segmentation by modifying a previously published algorithm (areal algorithm), including changing the intensity level, alternating the leaf-sequencing direction, or limiting the segment field size. The algorithm was tested with 1000 random intensity patterns with dimensions of 21*27 cm/sup 2/, 800 intensity patterns with higher intensity outside the jaw overtravel limit, and three different types of clinical treatment plans that were undeliverable using a segmentation method from a commercial treatment planning system. The new algorithm achieved a success rate of 100% with these test patterns. For the 1000 random patterns, the new algorithm yields a similar average number of segments of 36.9+or-2.9 in comparison to 36.6+or-1.3 when using the areal algorithm. For the 800 patterns with higher intensities outside the jaw overtravel limits, the new algorithm results in an increase of 25% in the average number of segments compared to the areal algorithm. However, the areal algorithm fails to create deliverable segments for 90% of these patterns. Using a single isocenter, the new algorithm provides a solution to extend the usable IMRT field length from 21 to 27 cm for IMRT on a commercial linear accelerator using the step and shoot delivery method

1110

A hybrid model for smoke simulation

A smoke simulation approach based on the integration of traditional particle systems and density functions is presented in this paper. By attaching a density function to each particle as its attribute, the diffusion of smoke can be described by the variation of particles' density functions, along with the effect on airflow by controlling particles' movement and fragmentation. In addition, a continuous density field for realistic rendering can be generated quickly through the look-up tables of particle's density functions. Compared with traditional particle systems, this approach can describe smoke diffusion, and provide a continuous density field for realistic rendering with much less computation. A quick rendering scheme is also presented in this paper as a useful preview tool for tuning appropriate parameters in the smoke model

545

Interaction and presence in the clinical relationship: virtual reality (VR) as communicative medium between patient and therapist

The great potential offered by virtual reality (VR) to clinical psychologists derives prevalently from the central role, in psychotherapy, occupied by the imagination and by memory. These two elements, which are fundamental in our life, present absolute and relative limits to the individual potential. Using VR as an advanced imaginal system, an experience that is able to reduce the gap existing between imagination and reality, it is possible to transcend these limits. In this sense, VR can improve the efficacy of a psychological therapy for its capability of reducing the distinction between the computer's reality and the conventional reality. Two are the core characteristics of this synthetic imaginal experience: the perceptual illusion of nonmediation and the possibility of building and sharing a common ground. In this sense, experiencing presence in a clinical virtual environment (VE), such as a shared virtual hospital, requires more than reproduction of the physical features of external reality. It requires the creation and sharing of the cultural web that makes meaningful, and therefore visible, both people and objects populating the environment. The paper outlines a framework for supporting the development and tuning of clinically oriented VR systems

992

Cross-entropy and rare events for maximal cut and partition problems

We show how to solve the maximal cut and partition problems using a randomized algorithm based on the cross-entropy method. For the maximal cut problem, the proposed algorithm employs an auxiliary Bernoulli distribution, which transforms the original deterministic network into an associated stochastic one, called the associated stochastic network (ASN). Each iteration of the randomized algorithm for the ASN involves the following two phases: (1) generation of random cuts using a multidimensional Ber(p) distribution and calculation of the associated cut lengths (objective functions) and some related quantities, such as rare-event probabilities; (2) updating the parameter vector p on the basis of the data collected in the first phase. We show that the Ber(p) distribution converges in distribution to a degenerated one, Ber(p/sub d/*), p/sub d/* = (p/sub d/,/sub 1/, p/sub d,n/) in the sense that some elements of p/sub d/*, will be unities and the rest zeros. The unity elements of p/sub d/* uniquely define a cut which will be taken as the estimate of the maximal cut. A similar approach is used for the partition problem. Supporting numerical results are given as well. Our numerical studies suggest that for the maximal cut and partition problems the proposed algorithm typically has polynomial complexity in the size of the network

83

A distributed mobile agent framework for maintaining persistent distance education

Mobile agent techniques involve distributed control if communication is required among different types of agents, especially when mobile agents can migrate from station to station. This technique can be implemented in a distributed distance learning environment, which allows students or instructors to login from anywhere to a central server in an education center while still retaining the look-and-feel of personal setups. In this research paper, we propose a distributed agent framework along with its communication messages to facilitate mobile personal agents, which serve three different groups of distance education users: instructors, students, and system administrators. We propose an agent communication framework as well as agent evolution states of mobile agents. The communication architecture and message transmission protocols are illustrated. The system is implemented on the Windows platform to support nomadic accessibility of remote distance learning users. Personal data also migrate with the mobile agents, allowing users to maintain accessibility to some extent even when the Internet connection is temperately disconnected. Using user-friendly personal agents, a distance education platform can include different tools to meet different needs for users

1254

Supporting unified interface to wrapper generator in integrated information retrieval

Given the ever-increasing scale and diversity of information and applications on the Internet, improving the technology of information retrieval is an urgent research objective. Retrieved information is either semi-structured or unstructured in format and its sources are extremely heterogeneous. In consequence, the task of efficiently gathering and extracting information from documents can be both difficult and tedious. Given this variety of sources and formats, many choose to use mediator/wrapper architecture, but its use demands a fast means of generating efficient wrappers. In this paper, we present a design for an automatic eXtensible Markup Language (XML)-based framework with which to generate wrappers rapidly. Wrappers created with this framework support a unified interface for a meta-search information retrieval system based on the Internet Search Service using the Common Object Request Broker Architecture (CORBA) standard. Greatly advantaged by the compatibility of CORBA and XML, a user can quickly and easily develop information-gathering applications, such as a meta-search engine or any other information source retrieval method. The two main things our design provides are a method of wrapper generation that is fast, simple, and efficient, and a wrapper generator that is CORBA and XML-compliant and that supports a unified interface

1211

Hybrid decision tree

In this paper, a hybrid learning approach named hybrid decision tree (HDT) is proposed. HDT simulates human reasoning by using symbolic learning to do qualitative analysis and using neural learning to do subsequent quantitative analysis. It generates the trunk of a binary HDT according to the binary information gain ratio criterion in an instance space defined by only original unordered attributes. If unordered attributes cannot further distinguish training examples falling into a leaf node whose diversity is beyond the diversity-threshold, then the node is marked as a dummy node. After all those dummy nodes are marked, a specific feedforward neural network named FANNC that is trained in an instance space defined by only original ordered attributes is exploited to accomplish the learning task. Moreover, this paper distinguishes three kinds of incremental learning tasks. Two incremental learning procedures designed for example-incremental learning with different storage requirements are provided, which enables HDT to deal gracefully with data sets where new data are frequently appended. Also a hypothesis-driven constructive induction mechanism is provided, which enables HDT to generate compact concept descriptions

644

Three-dimensional spiral MR imaging: application to renal multiphase contrast-enhanced angiography

A fast MR pulse sequence with spiral in-plane readout and conventional 3D partition encoding was developed for multiphase contrast-enhanced magnetic resonance angiography (CE-MRA) of the renal vasculature. Compared to a standard multiphase 3D CE-MRA with FLASH readout, an isotropic in-plane spatial resolution of 1.4*1.4 mm/sup 2/ over 2.0*1.4 mm/sup 2/ could be achieved with a temporal resolution of 6 sec. The theoretical gain of spatial resolution by using the spiral pulse sequence and the performance in the presence of turbulent flow was evaluated in phantom measurements. Multiphase 3D CE-MRA of the renal arteries was performed in five healthy volunteers using both techniques. A deblurring technique was used to correct the spiral raw data. Thereby, the off-resonance frequencies were determined by minimizing the imaginary part of the data in image space. The chosen correction algorithm was able to reduce image blurring substantially in all MRA phases. The image quality of the spiral CE-MRA pulse sequence was comparable to that of the FLASH CE-MRA with increased spatial resolution and a 25% reduced contrast-to-noise ratio. Additionally, artifacts specific to spiral MRI could be observed which had no impact on the assessment of the renal arteries

601

Recent researches of human science on railway systems

This paper presents research of human science on railway systems at RTRI. They are roughly divided into two categories: research to improve safety and those to improve comfort. On the former subject, for the safeguard against accidents caused by human errors, we have promoted studies of psychological aptitude test, various research to evaluate train drivers' working conditions and environments, and new investigations to minimize the risk of passenger casualties at train accidents. On the latter subject, we have developed new methods to evaluate the riding comfort including that of tilt train, and started research on the improvement of railway facilities for the aged and the disabled from the viewpoint of universal design

759

Mathematical properties of dominant AHP and concurrent convergence method

This study discusses the mathematical structure of the dominant AHP and the concurrent convergence method which were originally developed by Kinoshita and Nakanishi. They introduced a new concept of a regulating alternative into an analyzing tool for a simple evaluation problem with a criterion set and an alternative set. Although the original idea of the dominant AHP and the concurrent convergence method is unique, the dominant AHP and the concurrent convergence method are not sufficiently analyzed in mathematical theory. This study shows that the dominant AHP consists of a pair of evaluation rules satisfying a certain property of overall evaluation vectors. This study also shows that the convergence of concurrent convergence method is guaranteed theoretically

1349

Efficient simplicial reconstructions of manifolds from their samples

An algorithm for manifold learning is presented. Given only samples of a finite-dimensional differentiable manifold and no a priori knowledge of the manifold's geometry or topology except for its dimension, the goal is to find a description of the manifold. The learned manifold must approximate the true manifold well, both geometrically and topologically, when the sampling density is sufficiently high. The proposed algorithm constructs a simplicial complex based on approximations to the tangent bundle of the manifold. An important property of the algorithm is that its complexity depends on the dimension of the manifold, rather than that of the embedding space. Successful examples are presented in the cases of learning curves in the plane, curves in space, and surfaces in space; in addition, a case when the algorithm fails is analyzed

1421

Extracting linguistic DNA: NStein goes to work for UPI

It's a tantalizing problem for categorization. United Press International (UPI) has more than 700 correspondents creating thousands of stories every week, running the gamut from business news to sports to entertainment to global coverage of America's war on terrorism. And while UPI and others news services have mechanisms for adding keywords and categorizing their content, UPI recognized a need to add more automation to the process. With the recent growth and improvement in tools for Computer-Aided Indexing (CAI), UPI undertook a process of looking at its needs and evaluating the many CAI tools out there. In the end, they chose technology from Montreal-based NStein Technologies. "Our main objective was to acquire the best CAI tool to help improve our customers' access and interaction with our content," says Steve Sweet, CIO at UPI. "We examined a number of solutions, and NStein's NServer suite clearly came out on top. The combination of speed, scalability, accuracy, and flexibility was what really sold us."

872

Shortchanging the future of information technology: the untapped resource

Building on ideas from a virtual workshop and additional input from the scientific community, the CISE Directorate at the National Science Foundation established the Information Technology Workforce Program (ITWF) in March 2000 to support a broad set of scientific research studies focused on the under-representation of women and minorities in the information technology workforce. In this paper, we explore various approaches that the funded researchers are taking to address the problem of women in information technology. We begin with a brief history of the ITWF, and then focus on some of the research projects in terms of their goals, approaches, and expected outcomes

837

Ten suggestions for a gender-equitable CS classroom

Though considerable attention has been paid to the creation of a nurturing environment for women in the field of computer science, proposed solutions have primarily focused on activities outside of the classroom. This paper presents a list of suggestions for modifications to both the pedagogy and content of CS courses designed to make the CS classroom environment more inviting for women students

1048

Parallel and distributed Haskells

Parallel and distributed languages specify computations on multiple processors and have a computation language to describe the algorithm, i.e. what to compute, and a coordination language to describe how to organise the computations across the processors. Haskell has been used as the computation language for a wide variety of parallel and distributed languages, and this paper is a comprehensive survey of implemented languages. It outlines parallel and distributed language concepts and classifies Haskell extensions using them. Similar example programs are used to illustrate and contrast the coordination languages, and the comparison is facilitated by the common computation language. A lazy language is not an obvious choice for parallel or distributed computation, and we address the question of why Haskell is a common functional computation language

1030

Comparison of automated digital elevation model extraction results using along-track ASTER and across-track SPOT stereo images

A digital elevation model (DEM) can be extracted automatically from stereo satellite images. During the past decade, the most common satellite data used to extract DEM was the across-track SPOT. Recently, the addition of along-track ASTER data, which can be downloaded freely, provides another attractive alternative to extract DEM data. This work compares the automated DEM extraction results using an ASTER stereo pair and a SPOT stereo pair over an area of hilly mountains in Drum Mountain, Utah, when compared to a USGS 7.5-min DEM standard product. The result shows that SPOT produces better DEM results in terms of accuracy and details, if the radiometric variations between the images, taken on subsequent satellite revolutions, are small. Otherwise, the ASTER stereo pair is a better choice because of simultaneous along-track acquisition during a single pass. Compared to the USGS 7.5-min DEM, the ASTER and the SPOT extracted DEMs have a standard deviation of 11.6 and 4.6 m, respectively

1075

Numerical simulation of information recovery in quantum computers

Decoherence is the main problem to be solved before quantum computers can be built. To control decoherence, it is possible to use error correction methods, but these methods are themselves noisy quantum computation processes. In this work, we study the ability of Steane's and Shor's fault-tolerant recovering methods, as well as a modification of Steane's ancilla network, to correct errors in qubits. We test a way to measure correctly ancilla's fidelity for these methods, and state the possibility of carrying out an effective error correction through a noisy quantum channel, even using noisy error correction methods

1389

The case for activity based management

In today's stormy economic climate businesses need Activity Based Management (ABM) more than ever before. In an economic downturn it is a vital tool for pinpointing a business' most profitable customers, products, regions or channels, as well as uncovering the costs of individual business processes that may need to be improved in order to drive higher profit levels. Changes may be afoot in the ABM market, but Armstrong Laing Group CEO Mike Sherratt argues that businesses need specialists with an ABM focus to keep up with their requirements in such a climate. He looks at what benefits a `best-of-breed' ABM system can offer businesses and contends that businesses must choose carefully when going down the ABM route - and also ask themselves the question whether 'generalist' organisations will be able to deliver the best possible ABM solution

799

Electronic reserves at University College London: understanding the needs of academic departments

This article describes a recent project at University College London to explore the feasibility of providing a service to improve access to electronic course materials. Funded by the Higher Education Funding Council for England (HEFCE), the project was not simply to set up an electronic reserve. By undertaking a needs analysis of academic departments, the project was able to tailor the design of the new service appropriately. While new initiatives in libraries are often established using project funding, this work was unique in being research-led. It also involved collaboration between library and computing staff and learning technologists

721

The results of experimental studies of the reflooding of fuel-rod assemblies from above and problems for future investigations

Problems in studying the reflooding of assemblies from above conducted at foreign and Russian experimental installations are considered. The efficiency of cooling and flow reversal under countercurrent flow of steam and water, as well as the scale effect are analyzed. The tasks for future experiments that are necessary for the development of modern correlations for the loss-of-coolant accident (LOCA) computer codes are stated

764

Lattice Boltzmann schemes for quantum applications

We review the basic ideas behind the quantum lattice Boltzmann equation (LBE), and present a few thoughts on the possible use of such an equation for simulating quantum many-body problems on both (parallel) electronic and quantum computers

1331

Enterprise content integration III: Agari Mediaware's Media Star

Since we introduced the term Enterprise Content Integration (ECI) in January, the concept has gained momentum in the market. In addition to Context Media's Interchange Platform and Savantech's Photon Commerce, Agari Mediaware's Media Star is in the fray. It is a middleware platform that allows large media companies to integrate their digital systems with great flexibility

1374

Using technology to facilitate the design and delivery of warnings

This paper describes several ways in which new technologies can assist in the design and delivery of warnings. There are four discussion points: (1) current product information can be delivered via the Internet; (2) computer software and hardware are available to assist in the design, construction, and production of visual and auditory warnings; (3) various detection devices can be used to recognize instances in which warnings might be delivered; and (4) a warning presentation can be modified to fit conditions and persons. Implications, example applications and future prospects of these points are described

1459

Wave propagation related to high-speed train. A scaled boundary FE-approach for unbounded domains

Analysis of wave propagation in solid materials under moving loads is a topic of great interest in railway engineering. The objective of the paper is three-dimensional modelling of high-speed train related ground vibrations; in particular the question of how to account for the unbounded media is addressed. For efficient and accurate modelling of railway structural components taking the unbounded media into account, a hybrid method based on a combination of the conventional finite element method and scaled boundary finite element method is established. In the paper, element matrices and solution procedures for the scaled boundary finite element method (SBFEM) are derived. A non-linear finite element iteration scheme using Lagrange multipliers and coupling between the unbounded domain and the finite element domain are also discussed. Two numerical examples including one example demonstrating the dynamical response of a railroad section are presented to demonstrate the performance of the proposed method

1088

Parallel implicit predictor corrector methods

The performance of parallel codes for the solution of initial value problems is usually strongly sensitive to the dimension of the continuous problem. This is due to the overhead related to the exchange of information among the processors and motivates the problem of minimizing the amount of communications. According to this principle, we define the so called Parallel Implicit Predictor Corrector Methods and in this class we derive A-stable, L-stable and numerically zero-stable formulas. The latter property refers to the zero-stability condition of a given formula when roundoff errors are introduced in its coefficients due to their representation in finite precision arithmetic. Some numerical experiment show the potentiality of this approach

1269

Minimizing the number of successor states in the stubborn set method

Combinatorial explosion which occurs in parallel compositions of LTSs can be alleviated by letting the stubborn set method construct on-the-fly a reduced LTS that is CFFD- or CSP-equivalent to the actual parallel composition. This article considers the problem of minimizing the number of successor states of a given state in the reduced LTS. The problem can be solved by constructing an and/or-graph with weighted vertices and by finding a set of vertices that satisfies a certain constraint such that no set of vertices satisfying the constraint has a smaller sum of weights. Without weights, the and/or-graph can be constructed in low-degree polynomial time w.r.t. the length of the input of the problem. However, since actions can be nondeterministic and transitions can share target states, it is not known whether the weights are generally computable in polynomial time. Consequently, it is an open problem whether minimizing the number of successor states is as "easy" as minimizing the number of successor transitions

679

Himalayan information system: a proposed model

The information explosion and the development in information technology force us to develop information systems in various fields. The research on Himalaya has achieved phenomenal growth in recent years in India. The information requirements of Himalayan researchers are divergent in nature. In order to meet these divergent needs, all information generated in various Himalayan research institutions has to be collected and organized to facilitate free flow of information. This paper describes the need for a system for Himalayan information. It also presents the objectives of Himalayan information system (HIMIS). It discusses in brief the idea of setting up a HIMIS and explains its utility to the users. It appeals to the government for supporting the development of such system

917

Efficient transitive closure reasoning in a combined class/part/containment hierarchy

Class hierarchies form the backbone of many implemented knowledge representation and reasoning systems. They are used for inheritance, classification and transitive closure reasoning. Part hierarchies are also important in artificial intelligence. Other hierarchies, e.g. containment hierarchies, have received less attention in artificial intelligence. This paper presents an architecture and an implementation of a hierarchy reasoner that integrates a class hierarchy, a part hierarchy, and a containment hierarchy into one structure. In order to make an implemented reasoner useful, it needs to operate at least at speeds comparable to human reasoning. As real-world hierarchies are always large, special techniques need to be used to achieve this. We have developed a set of parallel algorithms and a data representation called maximally reduced tree cover for that purpose. The maximally reduced tree cover is an improvement of a materialized transitive closure representation which has appeared in the literature. Our experiments with a medical vocabulary show that transitive closure reasoning for combined class/part/containment hierarchies in near constant time is possible for a fixed hardware configuration

585

Fuzzy system modeling in pharmacology: an improved algorithm

In this paper, we propose an improved fuzzy system modeling algorithm to address some of the limitations of the existing approaches identified during our modeling with pharmacological data. This algorithm differs from the existing ones in its approach to the cluster validity problem (i.e., number of clusters), the projection schema (i.e., input membership assignment and rule determination), and significant input determination. The new algorithm is compared with the Bazoon-Turksen model, which is based on the well-known Sugeno-Yasukawa approach. The comparison was made in terms of predictive performance using two different data sets. The first comparison was with a two variable nonlinear function prediction problem and the second comparison was with a clinical pharmacokinetic modeling problem. It is shown that the proposed algorithm provides more precise predictions. Determining the degree of significance for each input variable, allows the user to distinguish their relative importance

111

Modification for synchronization of Rossler and Chen chaotic systems

Active control is an effective method for making two identical Rossler and Chen systems be synchronized. However, this method works only for a certain class of chaotic systems with known parameters both in drive systems and response systems. Modification based on Lyapunov stability theory is proposed in order to overcome this limitation. An adaptive synchronization controller, which can make the states of two identical Rossler and Chen systems globally asymptotically synchronized in the presence of system's unknown constant parameters, is derived. Especially, when some unknown parameters are positive, we can make the controller more simple, besides, the controller is independent of those positive uncertain parameters. At last, when the condition that arbitrary unknown parameters in two systems are identical constants is cancelled, we demonstrate that it is possible to synchronize two chaotic systems. All results are proved using a well-known Lyapunov stability theorem. Numerical simulations are given to validate the proposed synchronization approach

1195

Sharpening the estimate of the stability constant in the maximum-norm of the Crank-Nicolson scheme for the one-dimensional heat equation

This paper is concerned with the stability constant C/sub infinity / in the maximum-norm of the Crank-Nicolson scheme applied. to the one-dimensional heat equation. A well known result due to S.J. Serdyukova is that C/sub infinity / < 23. In the present paper, by using a sharp resolvent estimate for the discrete Laplacian together with the Cauchy formula, it is shown that 3 <or= C/sub infinity / < 4.325. This bound also holds when the heat equation is considered on a bounded interval along with Dirichlet or Neumann boundary conditions

1168

Computing failure probabilities. Applications to reliability analysis

The paper presents one method for calculating failure probabilities with applications to reliability analysis. The method is based on transforming the initial set of variables to a n-dimensional uniform random variable in the unit hypercube, together with the limit condition set and calculating the associated probability using a recursive method based on the Gauss-Legendre quadrature formulas to calculate the resulting multiple integrals. An example of application is used to illustrate the proposed method

578

New approach to standing phase angle reduction for power system restoration

During power system restoration, it is necessary to check the phase angle between two buses before closing circuit breakers to connect a line between them. These angles may occur across a tie line between two systems or between two connected subsystems within a system. In case of large standing phase angle (SPA) difference the synchro-check relay does not allow closing of the breaker for this line. Therefore, this excessive SPA has to be reduced before attempting to connect the line. In this paper, a new and fast method for reducing SPA is presented. For this purpose, the standing phase angle difference between two specific buses is represented in terms of sensitivity factors associated with the change in active power generations and consumption at the buses. Then, the proposed method reschedule generation of selected units or shed load of selected buses to reduce excessive SPA difference between two buses based on sensitivity factors

684

Individual decision making using fuzzy set theory

The paper shows the importance of decision making by an individual and highlights the prime domain of decision making where fuzzy set theory can be used as a tool. Fuzzy set theory has been used on rational model of decision making to arrive at the desired conclusion

1294

Multicriterion optimization of composite laminates for maximum failure margins with an interactive descent algorithm

An interactive multicriterion optimization method for composite laminates subjected to multiple loading conditions is introduced. Laminate margins to initial failure (first ply failure, FPF) with respect of the applied loading conditions are treated as criteria. The original problem is reduced to a, bicriterion problem by introducing parameters to combine criteria in a linear manner. The problem is solved by using an interactive descent algorithm. Both the conditions required for a discrete procedure to converge towards a Pareto optimum and numerical examples are given

808

A novel control logic for fast valving operations

This letter proposes new control logic for operating parallel valves in fast valving schemes in order to improve the transient stability performance of power systems. A fast valving scheme using parallel valves overcomes many of the limitations of the conventional scheme. The proposed control logic for operating these valves has been applied to a typical single machine infinite bus system. Single as well as multiple stroke operations for controlling the turbine power output have been studied with the new control sequences. Encouraging results have been shown over the conventional schemes of fast valving

723

Simulation of physicochemical processes of erosion-corrosion of metals in two-phase flows

A computational model for the erosion-corrosion of the metals used in power equipment in two-phase flows (RAMEK-2) was developed. The results of calculations of the dependency of the intensity of the erosion-corrosion of structural steels as a function of the thermodynamic, hydrodynamic and water chemistry parameters of these flows in the working paths of thermal power stations and nuclear power stations are presented in a three-dimensional space. On the basis of mathematical models, application software was created for forecasting the erosion-corrosion resource and for optimizing the rules on diagnosis and protective maintenance of erosion-corrosion of the elements of the wet-steam path in power stations

766

Physical quantum algorithms

I review the differences between classical and quantum systems, emphasizing the connection between no-hidden variable theorems and superior computational power of quantum computers. Using quantum lattice gas automata as examples, I describe possibilities for efficient simulation of quantum and classical systems with a quantum computer. I conclude with a list of research directions

1333

The crossing number of P(N, 3)

It is proved that the crossing number of the generalized Petersen graph P(3k + h, 3) is k + h if h in {0, 2} and k + 3 if h = 1, for each k >or= 3, with the single exception of P(9,3), whose crossing number is 2

1376

Enhanced product support through intelligent product manuals

The scope of this paper is the provision of intelligent product support within the distributed Intranet/Internet environment. From the point of view of user requirements, the limitations of conventional product manuals and methods of authoring them are first outlined. It is argued that enhanced product support requires new technology solutions both for product manuals and for their authoring and presentation. The concept and the architecture of intelligent product manuals are then discussed. A prototype system called ProARTWeb is presented to demonstrate advanced features of intelligent product manuals. Next, the problem of producing such manuals in a cost-effective way is addressed and a concurrent engineering approach to their authoring is proposed. An integrated environment for collaborative authoring called ProAuthor is described to illustrate the approach suggested and to show how consistent, up-to-date and user-oriented-product manuals can be designed. The solutions presented here enable product knowledge to be captured and delivered to users and developers of product manuals when, where and in the form they need it

1032

Satellite image collection optimization

Imaging satellite systems represent a high capital cost. Optimizing the collection of images is critical for both satisfying customer orders and building a sustainable satellite operations business. We describe the functions of an operational, multivariable, time dynamic optimization system that maximizes the daily collection of satellite images. A graphical user interface allows the operator to quickly see the results of what if adjustments to an image collection plan. Used for both long range planning and daily collection scheduling of Space Imaging's IKONOS satellite, the satellite control and tasking (SCT) software allows collection commands to be altered up to 10 min before upload to the satellite

1077

Quantum learning and universal quantum matching machine

Suppose that three kinds of quantum systems are given in some unknown states |f>/sup (X)N/, |g/sub 1/>/sup (X)K/, and |g/sub 2/>/sup (X)K/, and we want to decide which template state |g/sub 1/> or |g/sub 2/>, each representing the feature of the pattern class C/sub 1/ or C/sub 2/, respectively, is closest to the input feature state |f>. This is an extension of the pattern matching problem into the quantum domain. Assuming that these states are known a priori to belong to a certain parametric family of pure qubit systems, we derive two kinds of matching strategies. The first one is a semiclassical strategy that is obtained by the natural extension of conventional matching strategies and consists of a two-stage procedure: identification (estimation) of the unknown template states to design the classifier (learning process to train the classifier) and classification of the input system into the appropriate pattern class based on the estimated results. The other is a fully quantum strategy without any intermediate measurement, which we might call as the universal quantum matching machine. We present the Bayes optimal solutions for both strategies in the case of K=1, showing that there certainly exists a fully quantum matching procedure that is strictly superior to the straightforward semiclassical extension of the conventional matching strategy based on the learning process

686

Technology CAD of SiGe-heterojunction field effect transistors

A 2D virtual wafer fabrication simulation suite has been employed for the technology CAD of SiGe channel heterojunction field effect transistors (HFETs). Complete fabrication process of SiGe p-HFETs has been simulated. The SiGe material parameters and mobility model were incorporated to simulate Si/SiGe p-HFETs with a uniform germanium channel having an L/sub eff/ of 0.5 mu m. A significant improvement in linear transconductance is observed when compared to control-silicon p-MOSFETs

1296

Development of visual design steering as an aid in large-scale multidisciplinary design optimization. I. Method development

A modified paradigm of computational steering (CS), termed visual design steering (VDS), is developed in this paper. The VDS paradigm is applied to optimal design problems to provide a means for capturing and enabling designer insights. VDS allows a designer to make decisions before, during or after an analysis or optimization via a visual environment, in order to effectively steer the solution process. The objective of VDS is to obtain a better solution in less time through the use of designer knowledge and expertise. Using visual representations of complex systems in this manner enables human experience and judgement to be incorporated into the optimal design process at appropriate steps, rather than having traditional black box solvers return solutions from a prescribed input set. Part I of this paper focuses on the research issues pertaining to the Graph Morphing visualization method created to represent an n-dimensional optimization problem using 2-dimensional and 3-dimensional visualizations. Part II investigates the implementation of the VDS paradigm, using the graph morphing approach, to improve an optimal design process. Specifically, the following issues are addressed: impact of design variable changes on the optimal design space; identification of possible constraint redundancies; impact of constraint tolerances on the optimal solution: and smoothness of the objective function contours. It is demonstrated that graph morphing can effectively reduce the complexity and computational time associated with some optimization problems

915

A meteorological fuzzy expert system incorporating subjective user input

We present a fuzzy expert system, MEDEX, for forecasting gale-force winds in the Mediterranean basin. The most successful local wind forecasting in this region is achieved by an expert human forecaster with access to numerical weather prediction products. That forecaster's knowledge is expressed as a set of 'rules-of-thumb'. Fuzzy set methodologies have proved well suited for encoding the forecaster's knowledge, and for accommodating the uncertainty inherent in the specification of rules, as well as in subjective and objective input. MEDEX uses fuzzy set theory in two ways: as a fuzzy rule base in the expert system, and for fuzzy pattern matching to select dominant wind circulation patterns as one input to the expert system. The system was developed, tuned, and verified over a two-year period, during which the weather conditions from 539 days were individually analyzed. Evaluations of MEDEX performance for both the onset and cessation of winter and summer winds are presented, and demonstrate that MEDEX has forecasting skill competitive with the US Navy's regional forecasting center in Rota, Spain

587

An improved self-organizing CPN-based fuzzy system with adaptive back-propagation algorithm

This paper describes an improved self-organizing CPN-based (Counter-Propagation Network) fuzzy system. Two self-organizing algorithms IUSOCPN and ISSOCPN, being unsupervised and supervised respectively, are introduced. The idea is to construct the neural-fuzzy system with a two-phase hybrid learning algorithm, which utilizes a CPN-based nearest-neighbor clustering scheme for both structure learning and initial parameters setting, and a gradient descent method with adaptive learning rate for fine tuning the parameters. The obtained network can be used in the same way as a CPN to model and control dynamic systems, while it has a faster learning speed than the original back-propagation algorithm. The comparative results on the examples suggest that the method is fairly efficient in terms of simple structure, fast learning speed, and relatively high modeling accuracy

950

Quantum sensitive dependence

Wave functions of bounded quantum systems with time-independent potentials, being almost periodic functions, cannot have time asymptotics as in classical chaos. However, bounded quantum systems with time-dependent interactions, as used in quantum control, may have continuous spectrum and the rate of growth of observables is an issue of both theoretical and practical concern. Rates of growth in quantum mechanics are discussed by constructing quantities with the same physical meaning as those involved in the classical Lyapunov exponent. A generalized notion of quantum sensitive dependence is introduced and the mathematical structure of the operator matrix elements that correspond to different types of growth is characterized

113

Quantum limit on computational time and speed

We investigate if physical laws can impose limits on computational time and speed of a quantum computer built from elementary particles. We show that the product of the speed and the running time of a quantum computer is limited by the type of fundamental interactions present inside the system. This will help us to decide as to what type of interaction should be allowed in building quantum computers in achieving the desired speed

1197

Numerical behaviour of stable and unstable solitary waves

In this paper we analyse the behaviour in time of the numerical approximations to solitary wave solutions of the generalized Benjamin-Bona-Mahony equation. This equation possesses an important property: the stability of these solutions depends on their velocity. We identify the error propagation mechanisms in both the stable and unstable case. In particular, we show that in the stable case, numerical methods that preserve some conserved quantities of the problem are more appropriate for the simulation of this kind of solutions

928

Weighted energy linear quadratic regulator vibration control of piezoelectric composite plates

In this paper on finite element linear quadratic regulator (LQR) vibration control of smart piezoelectric composite plates, we propose the use of the total weighted energy method to select the weighting matrices. By constructing the optimal performance function as a relative measure of the total kinetic energy, strain energy and input energy of the system, only three design variables need to be considered to achieve a balance between the desired higher damping effect and lower input cost. Modal control analysis is used to interpret the effects of three energy weight factors on the damping ratios and modal voltages and it is shown that the modal damping effect will increase with the kinetic energy weight factor, approaching square root (2/2) as the strain energy weight factor increases and decrease with the input energy weight factor. Numerical results agree well with those from the modal control analysis. Since the control problem is simplified to three design variables only, the computational cost will be greatly reduced and a more accurate structural control analysis becomes more attractive for large systems

1256

High-speed consistency checking for hypothetical reasoning systems using inference path network

Hypothetical reasoning is popular in fault diagnostics and design systems, but slow reasoning speed is its drawback. The goal of the current study is developing hypothetical reasoning based on an inference path network, which would overcome this drawback. In hypothetical reasoning systems based on an inference path network, there is much room for improvement regarding the computing costs of connotation processing and consistency checking. The authors of this study demonstrate improvement ideas regarding one of these problems, namely, consistency checking. First, the authors obtained necessary and sufficient conditions under which inconsistencies occur during hypothesis composition. Based on the obtained results, the authors proposed an algorithm for speeding up the process of consistency checking. Processing with this algorithm in its core consists of transforming the inference path network in such a way that inconsistencies do not occur during the hypothesis composition, under the condition of unchanged solution hypotheses. The efficiency of this algorithm was confirmed by tests

1213

A knowledge intensive multi-agent framework for cooperative/collaborative design modeling and decision support of assemblies

Multi-agent modeling has emerged as a promising discipline for dealing with the decision making process in distributed information system applications. One of such applications is the modeling of distributed design or manufacturing processes which can link up various designs or manufacturing processes to form a virtual consortium on a global basis. This paper proposes a novel knowledge intensive multi-agent cooperative/collaborative framework for concurrent intelligent design and assembly planning, which integrates product design, design for assembly, assembly planning, assembly system design, and assembly simulation subjected to econo-technical evaluations. An AI protocol based method is proposed to facilitate the integration of intelligent agents for assembly design, planning, evaluation and simulation processes. A unified class of knowledge intensive Petri nets is defined using the OO knowledge-based Petri net approach and used as an AI protocol for handling both the integration and the negotiation problems among multi-agents. The detailed cooperative/collaborative mechanism and algorithms are given based on the knowledge object cooperation formalisms. As such, the assembly-oriented design system can easily be implemented under the multi-agent-based knowledge-intensive Petri net framework with concurrent integration of multiple cooperative knowledge sources and software. Thus, product design and assembly planning can be carried out simultaneously and intelligently in an entirely computer-aided concurrent design and assembly planning system

646

Vibration control of structure by using tuned mass damper (development of system which suppress displacement of auxiliary mass)

In vibration control of a structure by using an active tuned mass damper (ATMD), stroke of the auxiliary mass is so limited that it is difficult to control the vibration in the case of large disturbance input. In this paper, two methods are proposed for the problem. One of the methods is a switching control system by two types of controllers. One of the controllers is a normal controller under small relative displacement of the auxiliary mass, and the other is not effective only for first mode of vibration under large relative displacement of the auxiliary mass. New variable gain control system is constructed by switching these two controllers. The other method is the brake system. In active vibration control, it is necessary to use actuator for active control. By using the actuator, the proposed system puts on the brake to suppress displacement increase of the auxiliary mass under large disturbance input. Finally, the systems are designed and the effectiveness of the systems is confirmed by the simulation

603

PGE helps customers reduce energy costs

A new service from Portland General Electric (PGE, Portland, Oregon, US) is saving customers tens of thousands of dollars in energy costs. PGE created E-Manager to allow facility managers to analyze their energy consumption online at 15-minute intervals. Customers can go to the Web for complete data, powerful analysis tools and charts, helping them detect abnormal energy use and focus on costly problem areas

81

A scalable and efficient systolic algorithm for the longest common subsequence problem

A longest common subsequence (LCS) of two strings is a common subsequence of two strings of maximal length. The LCS problem is that of finding an LCS of two given strings and the length of the LCS. This problem has been the subject of much research because its solution can be applied in many areas. In this paper, a scalable and efficient systolic algorithm is presented. For two given strings of length m and n, where m>or=n, the algorithm can solve the LCS problem in m+2r-1 (respectively n+2r-1) time steps with r<n/2 (respectively r<m/2) processors. Experimental results show that the algorithm can be faster on multicomputers than all the previous systolic algorithms for the same problem

1157

Portal dose image prediction for dosimetric treatment verification in radiotherapy. II. An algorithm for wedged beams

A method is presented for calculation of a two-dimensional function, T/sub wedge/(x,y), describing the transmission of a wedged photon beam through a patient. This in an extension of the method that we have published for open (nonwedged) fields [Med. Phys. 25, 830-840 (1998)]. Transmission functions for open fields are being used in our clinic for prediction of portal dose images (PDI, i.e., a dose distribution behind the patient in a plane normal to the beam axis), which are compared with PDIs measured with an electronic portal imaging device (EPID). The calculations are based on the planning CT scan of the patient and on the irradiation geometry as determined in the treatment planning process. Input data for the developed algorithm for wedged beams are derived from (the already available) measured input data set for transmission prediction in open beams, which is extended with only a limited set of measurements in the wedged beam. The method has been tested for a PDI plane at 160 cm from the focus, in agreement with the applied focus-to-detector distance of our fluoroscopic EPIDs. For low and high energy photon beams (6 and 23 MV) good agreement (~1%) has been found between calculated and measured transmissions for a slab and a thorax phantom

1112

Blending parametric patches with subdivision surfaces

In this paper the problem of blending parametric surfaces using subdivision patches is discussed. A new approach, named removing-boundary, is presented to generate piecewise-smooth subdivision surfaces through discarding the outmost quadrilaterals of the open meshes derived by each subdivision step. Then the approach is employed both to blend parametric bicubic B-spline surfaces and to fill n-sided holes. It is easy to produce piecewise-smooth subdivision surfaces with both convex and concave corners on the boundary, and limit surfaces are guaranteed to be C/sup 2/ continuous on the boundaries except for a few singular points by the removing-boundary approach. Thus the blending method is very efficient and the blending surface generated is of good effect

547

Excess energy [cooling system]

The designers retrofitting a comfort cooling system to offices in Hertfordshire have been able to make use of the waste heat rejected. what's more they're now making it a standard solution for much larger projects

990

Pipelined broadcast with enhanced wormhole routers

This paper proposes a pipelined broadcast that broadcasts a message of size m in O(m+n-1) time in an n-dimensional hypercube. It is based on the replication tree, which is derived from reachable sets. It has greatly improved performance compared to Ho-Kao's (1995) algorithm with the time of O(m[n/log(n+1)]). The communication in the broadcast uses an all-port wormhole router with message replication capability. This paper includes the algorithm together with performance comparisons to previous schemes in a practical implementation

1423

P2P is dead, long live P2P

Picture the problem: a sprawling multinational has hundreds of offices, thousands of workers, and countless amounts of intellectual property scattered here, there, everywhere. In Kuala Lumpur an executive needs to see an internally-generated report on oil futures in central Asia-but where is it? London? New York? Moscow? With a few clicks of the mouse-and the right P2P technology deployed in-house-that executive will find and retrieve the report. Without P2P that might be impossible-certainly it would be time-consuming-and, right there, the argument for P2P implementations inside enterprises becomes clear. Who are the players? No companies have managed to stake out clear leads and the fact is that the P2P marketplace now is up for grabs-but the exciting news is that a range of small and startup businesses are trying to grab turf and quite probably, if the analysts are right, a few of these now little-known companies will emerge as digital content stars within the next few years. Cases in point: Groove Networks, Avaki, WorldStreet, Yaga, NextPage, and Kontiki. Very different companies-their approach to the markets radically differ-but, say the analysts, each is worth a close look because among them they are defining the future of P2P

870

Speaker identification from voice using neural networks

The paper provides three different schemes for speaker identification of personnel from their voice using artificial neural networks. The first scheme recognizes speakers by employing the classical backpropagation algorithm pre-trained with known voice samples of the persons. The second scheme provides a framework for classifying the known training samples of the voice features using a hierarchical architecture realized with a self-organizing feature map neural net. The first scheme is highly robust as it is capable of identifying the personnel from their noisy voice samples, but because of its excessive training time it has limited applications for a large voice database. The second scheme though not so robust as the former, however, can classify an unknown voice sample to its nearest class. The time needed for classification by the first scheme is always unique irrespective of the voice sample. It is proportional to the number of feedforward layers in the network. The time-requirement of the second classification scheme, however, is not free from the voice features and is proportional to the number of 2D arrays traversed by the algorithm on the hierarchical structure. The third scheme is highly robust and mis-classification is as low as 0.2 per cent. The third scheme combines the composite benefits of a radial basis function neural net and backpropagation trained neural net

835

Pioneering women in computer science

Although their contributions are not well documented, women have played an important role in the development of computer science. A survey of women pioneers demonstrates their influence in designing and programming the first electronic computers and languages, while laying the groundwork for women's expanding involvement in science

1173

A comprehensive chatter prediction model for face turning operation including tool wear effect

Presents a three-dimensional mechanistic frequency domain chatter model for face turning processes, that can account for the effects of tool wear including process damping. New formulations are presented to model the variation in process damping forces along nonlinear tool geometries such as the nose radius. The underlying dynamic force model simulates the variation in the chip cross-sectional area by accounting for the displacements in the axial and radial directions. The model can be used to determine stability boundaries under various cutting conditions and different states of flank wear. Experimental results for different amounts of wear are provided as a validation for the model

1136

Q-learning for risk-sensitive control

We propose for risk-sensitive control of finite Markov chains a counterpart of the popular Q-learning algorithm for classical Markov decision processes. The algorithm is shown to converge with probability one to the desired solution. The proof technique is an adaptation of the o.d.e. approach for the analysis of stochastic approximation algorithms, with most of the work involved used for the analysis of the specific o.d.e.s that arise

563

Getting the most out of intrusion detection systems

Intrusion detection systems (IDS) can play a very valuable role in the defence of a network. However, it is important to understand not just what it will do (and how it does it) - but what it won't do (and why). This article does not go into the technical working of IDS in too much detail, rather it limits itself to a discussion of some of the capabilities and failings of the technology

1272

Global action rules in distributed knowledge systems

Previously Z. Ras and J.M. Zytkow (2000) introduced and investigated query answering system based on distributed knowledge mining. The notion of an action rule was introduced by Z. Ras and A. Wieczorkowska (2000) and its application domain e-business was taken. In this paper, we generalize the notion of action rules in a similar way to handling global queries. Mainly, when values of attributes for a given customer, used in action rules, can not be easily changed by business user, definitions of these attributes are extracted from other sites of a distributed knowledge system. To be more precise, attributes at every site of a distributed knowledge system are divided into two sets: stable and flexible. Values of flexible attributes, for a given consumer, sometime can be changed and this change can be influenced and controlled by a business user. However, some of these changes (for instance to the attribute "profit') can not be done directly to a chosen attribute. In this case, definitions of such an attribute in terms of other attributes have to be learned. These new definitions are used to construct action rules showing what changes in values of flexible attributes, for a given consumer, are needed in order to re-classify this consumer the way business user wants. But, business user may be either unable or unwilling to proceed with actions leading to such changes. In all such cases we may search for definitions of these flexible attributes looking at either local or remote sites for help

1237

High-performance numerical pricing methods

The pricing of financial derivatives is an important field in finance and constitutes a major component of financial management applications. The uncertainty of future events often makes analytic approaches infeasible and, hence, time-consuming numerical simulations are required. In the Aurora Financial Management System, pricing is performed on the basis of lattice representations of stochastic multidimensional scenario processes using the Monte Carlo simulation and Backward Induction methods, the latter allowing for the exploitation of shared-memory parallelism. We present the parallelization of a Backward Induction numerical pricing kernel on a cluster of SMPs using HPF+, an extended version of High-Performance Fortran. Based on language extensions for specifying a hierarchical mapping of data onto an SMP cluster, the compiler generates a hybrid-parallel program combining distributed-memory and shared-memory parallelism. We outline the parallelization strategy adopted by the VFC compiler and present an experimental evaluation of the pricing kernel on an NEC SX-5 vector supercomputer and a Linux SMP cluster, comparing a pure MPI version to a hybrid-parallel MPI/OpenMP version

627

Comparison of non-stationary time series in the frequency domain

In this paper we compare two nonstationary time series using nonparametric procedures. Evolutionary spectra are estimated for the two series. Randomization tests are performed on groups of spectral estimates for both related and independent time series. Simulation studies show that in certain cases the tests perform reasonably well. The tests are applied to observed geological and financial time series

58

Robust speech recognition using probabilistic union models

This paper introduces a new statistical approach, namely the probabilistic union model, for speech recognition involving partial, unknown frequency-band corruption. Partial frequency-band corruption accounts for the effect of a family of real-world noises. Previous methods based on the missing feature theory usually require the identity of the noisy bands. This identification can be difficult for unexpected noise with unknown, time-varying band characteristics. The new model combines the local frequency-band information based on the union of random events, to reduce the dependence of the model on information about the noise. This model partially accomplishes the target: offering robustness to partial frequency-band corruption, while requiring no information about the noise. This paper introduces the theory and implementation of the union model, and is focused on several important advances. These new developments include a new algorithm for automatic order selection, a generalization of the modeling principle to accommodate partial feature stream corruption, and a combination of the union model with conventional noise reduction techniques to deal with a mixture of stationary noise and unknown, nonstationary noise. For the evaluation, we used the TIDIGITS database for speaker-independent connected digit recognition. The utterances were corrupted by various types of additive noise, stationary or time-varying, assuming no knowledge about the noise characteristics. The results indicate that the new model offers significantly improved robustness in comparison to other models

949

Reply to "Comment on: Teleportation of an unknown state by W state" [Phys. Lett. A 300 (2002) 324]

In our letter (see ibid., vol. 296, p. 161 (2002)), the main question we consider is whether a general three-particle W state can be used to realize the teleportation of an unknown qubit state. We give the positive answer to this question in our letter, and show that W state can be used to realize to do that probabilistically. We also discuss how to do it in detail in our letter. In the previous comment (see ibid., vol. 300, p. 324 (2002)), authors check carefully the mathematics calculation of our letter, find and point out a simple mathematics error about normalization coefficient of Eq. (1). This mathematics error induces the incorrect probability calculation of Eq. (6), and also an incorrect claim in first part of our letter

1407

Soft options for software upgrades?

Several new products claim to take the work out of installing software and patches, and even migrating operating systems. Software migration products fall into two broad categories. The drive imaging type is designed to make exact copies of a hard disk, either an entire drive or certain directories, so you can use it to back up data. The application management type is designed for more incremental upgrades and often provides additional features such as the ability to monitor or control users' access to applications

1093

A fuzzy logic approach to accommodate thermal stress and improve the start-up phase in combined cycle power plants

Use of combined cycle power generation plant has increased dramatically over the last decade. A supervisory control approach based on a dynamic model is developed, which makes use of proportional-integral-derivative (PID), fuzzy logic and fuzzy PID schemes. The aim is to minimize the steam turbine plant start-up time, without violating maximum thermal stress limits. An existing start-up schedule provides the benchmark by which the performance of candidate controllers is assessed. Improvements regarding possible reduced start-up times and satisfaction of maximum thermal stress restrictions have been realized using the proposed control scheme

1442

Using constructed types in C++ unions

The C++ Standard states that a union type cannot have a member with a nontrivial constructor or destructor. While at first this seems unreasonable, further thought makes it clear why this is the case: The crux of the problem is that unions don't have built-in semantics for denoting when a member is the "current" member of the union. Therefore, the compiler can't know when it's appropriate to call constructors or destructors on the union members. Still, there are good reasons for wanting to use constructed object types in a union. For example, you might want to implement a scripting language with a single variable type that can either be an integer, a string, or a list. A union is the perfect candidate for implementing such a composite type, but the restriction on constructed union members may prevent you from using an existing string or list class (for example, from the STL) to provide the underlying functionality. Luckily, a feature of C++ called placement new can provide a workaround

854

A conference's impact on undergraduate female students

In September of 2000, the 3rd Grace Hopper Celebration of Women in Computing was held in Cape Cod, Massachusetts. Along with a colleague from a nearby university, we accompanied seven of our female undergraduate students to this conference. This paper reports on how the conference experience immediately affected these students - what impressed them, what scared them, what it clarified for them. It also reports on how the context in which these students currently evaluate their ability, potential and opportunity in computer science is different now from what it was before the conference. Hopefully, by understanding their experience, we can gain some insight into things we can do for all of our undergraduate female students to better support their computer science and engineering education

811

Integration, the Web are key this season [tax]

Integration and the Web are driving many of the enhancements planned by tax preparation software vendors for this coming season

1392

Enlisting on-line residents: Expanding the boundaries of e-government in a Japanese rural township

The purpose of this article is to analyze and learn from an unusual way in which local bureaucrats in a Japanese rural township are using the Internet to serve their constituents by enlisting the support of "on-line residents." Successful e-government requires not only rethinking the potential uses of computer technology, but in adopting new patterns of decision-making, power sharing, and office management that many bureaucrats may not be predisposed to make. The main thesis of this article is that necessity and practicality can play a powerful motivational role in facilitating the incorporation of information technology (IT) at the level of local government. This case study of how bureaucrats in Towa-cho, a small, agricultural town in Northeastern Japan, have harnessed the Internet demonstrates clearly the fundamentals of building a successful e-government framework in this rural municipality, similar to many communities in Europe and North America today

782

Community technology and democratic rationalization

The objective of the paper is to explore questions of human agency and democratic process in the technical sphere through the example of "virtual community." The formation of relatively stable long-term group associations (community in the broad sense of the term), is the scene on which a large share of human development occurs. As such it is a fundamental human value mobilizing diverse ideologies and sensitivities. The promise of realizing this value in a new domain naturally stirs up much excitement among optimistic observers of the Internet. At the same time, the eagerness to place hopes for community in a technical system flies in the face of an influential intellectual tradition of technology criticism. This eagerness seems even more naive in the light of the recent commercialization of so much Internet activity. Despite the widespread skepticism, we believe the growth of virtual community is significant for an inquiry into the democratization of technology. We show that conflicting answers to the central question of the present theoretical debate - Is community possible on computer networks? epsilon neralize from particular features of systems and software prevalent at different stages in the development of computer networking. We conclude that research should focus instead on how to design computer networks to better support community activities and values

894

Improved detection of lung nodules by using a temporal subtraction technique

The authors evaluated the effect of a temporal subtraction technique for digital chest radiography with regard to the accuracy of detection of lung nodules. Twenty solitary lung nodules smaller than 30 mm in diameter, including 10 lung cancers and 10 benign nodules, were used. The nodules were grouped subjectively according to their subtlety. For nonnodular cases, 20 nodules without perceptible interval changes were selected. All chest radiographs were obtained by using a computed radiographic system, and temporal subtraction images were produced by using a program developed at the University of Chicago. The effect of the temporal subtraction image was evaluated by using an observer performance study, with use of receiver operating characteristic analysis. Observer performance with temporal subtraction images was substantially improved (A/sub z/ = 0.980 and 0.958), as compared with that without temporal subtraction images (A/sub z/ = 0.920 and 0.825) for the certified radiologists and radiology residents, respectively. The temporal subtraction technique clearly improved diagnostic accuracy for detecting lung nodules, especially subtle cases. In conclusion, the temporal subtraction technique is useful for improving detection accuracy for peripheral lung nodules on digital chest radiographs

1016

A scalable model of cerebellar adaptive timing and sequencing: the recurrent slide and latch (RSL) model

From the dawn of modern neural network theory, the mammalian cerebellum has been a favored object of mathematical modeling studies. Early studies focused on the fanout, convergence, thresholding, and learned weighting of perceptual-motor signals within the cerebellar cortex. This led to the still viable idea that the granule cell stage in the cerebellar cortex performs a sparse expansive recoding of the time-varying input vector. This recoding reveals and emphasizes combinations in a distributed representation that serves as a basis for the learned, state-dependent control actions engendered by cerebellar outputs to movement related centers. To make optimal use of available signals, the cerebellum must be able to sift the evolving state representation for the most reliable predictors of the need for control actions, and to use those predictors even if they appear only transiently and well in advance of the optimal time for initiating the control action. The paper proposes a modification to prior, population, models for cerebellar adaptive timing and sequencing. Since it replaces a population with a single element, the proposed RSL model is in one sense maximally efficient, and therefore optimal from the perspective of scalability

1053

A static semantics for Haskell

This paper gives a static semantics for Haskell 98, a non-strict purely functional programming language. The semantics formally specifies nearly all the details of the Haskell 98 type system, including the resolution of overloading, kind inference (including defaulting) and polymorphic recursion, the only major omission being a proper treatment of ambiguous overloading and its resolution. Overloading is translated into explicit dictionary passing, as in all current implementations of Haskell. The target language of this translation is a variant of the Girard-Reynolds polymorphic lambda calculus featuring higher order polymorphism. and explicit type abstraction and application in the term language. Translated programs can thus still be type checked, although the implicit version of this system is impredicative. A surprising result of this formalization effort is that the monomorphism restriction, when rendered in a system of inference rules, compromises the principal type property

707

Vector algebra proofs for geometry theorems

Vector mathematics can generate simple and powerful proofs of theorems in plane geometry. These proofs can also be used to generalize plane geometry theorems to higher dimensions. We present three vector proofs that show the power of this technique. 1. For any quadrilateral, the sum of the squares of the diagonals is less than or equal to the sum of the squares of the sides. 2. The area of a quadrilateral is half the product of the diagonals multiplied by the sine of an included angle. 3. One quarter of all triangles are acute (Based upon the options detailed below, with respect to the relative lengths of the sides). This paper presents a set of examples of vector mathematics applied to geometry problems. Some of the most beautiful and sophisticated proofs in mathematics involve using multiple representations of the same data. By leveraging the advantages of each representation one finds new and useful mathematical facts

742

Second term [International Telecommunication Union]

Later this month Yoshio Utsumi is expected to be re-elected for a second four year term as secretary general of the International Telecommunication Union. Here he talks to Matthew May about getting involved in internet addressing, the prospects for 3g, the need for further reform of his organisation... and the translating telephone

1317

Dynamic spectrum management for next-generation DSL systems

The performance of DSL systems is severely constrained by crosstalk due to the electromagnetic coupling among the multiple twisted pairs making up a phone cable. In order to reduce performance loss arising from crosstalk, DSL systems are currently designed under the assumption of worst-case crosstalk scenarios leading to overly conservative DSL deployments. This article presents a new paradigm for DSL system design, which takes into account the multi-user aspects of the DSL transmission environment. Dynamic spectrum management (DSM) departs from the current design philosophy by enabling transceivers to autonomously and dynamically optimize their communication settings with respect to both the channel and the transmissions of neighboring systems. Along with this distributed optimization, when an additional degree of coordination becomes available for future DSL deployment, DSM will allow even greater improvement in DSL performance. Implementations are readily applicable without causing any performance degradation to the existing DSLs under static spectrum management. After providing an overview of the DSM concept, this article reviews two practical DSM methods: iterative water-filling, an autonomous distributed power control method enabling great improvement in performance, which can be implemented through software options in some existing ADSL and VDSL systems; and vectored-DMT, a coordinated transmission/reception technique achieving crosstalk-free communication for DSL systems, which brings within reach the dream of providing universal Internet access at speeds close to 100 Mb/s to 500 m on 1-2 lines and beyond 1 km on 2-4 lines. DSM-capable DSL thus enables the broadband age

1352

Elastically adaptive deformable models

We present a technique for the automatic adaptation of a deformable model's elastic parameters within a Kalman filter framework for shape estimation applications. The novelty of the technique is that the model's elastic parameters are not constant, but spatio-temporally varying. The variation of the elastic parameters depends on the distance of the model from the data and the rate of change of this distance. Each pass of the algorithm uses physics-based modeling techniques to iteratively adjust both the geometric and the elastic degrees of freedom of the model in response to forces that are computed from the discrepancy between the model and the data. By augmenting the state equations of an extended Kalman filter to incorporate these additional variables, we are able to significantly improve the quality of the shape estimation. Therefore, the model's elastic parameters are always initialized to the same value and they are subsequently modified depending on the data and the noise distribution. We present results demonstrating the effectiveness of our method for both two-dimensional and three-dimensional data

869

An exactly solvable random satisfiability problem

We introduce a new model for the generation of random satisfiability problems. It is an extension of the hyper-SAT model of Ricci-Tersenghi, Weigt and Zecchina (2001), which is a variant of the famous K-SAT model: it is extended to q-state variables and relates to a different choice of the statistical ensemble. The model has an exactly solvable statistic: the critical exponents and scaling functions of the SAT/UNSAT transition are calculable at zero temperature, with no need of replicas, also with exact finite-size corrections. We also introduce an exact duality of the model, and show an analogy of thermodynamic properties with the random energy model of disordered spin system theory. Relations with error correcting codes are also discussed

65

The use of subtypes and stereotypes in the UML model

Based on users' experiences of Version 1.3 of the Unified Modeling Language (UML) of the Object Management Group (OMG), a Request For Information in 1999 elicited several responses which were asked to identify "problems" but not to offer any solutions. One of these responses is examined for "problems" relating to the UML metamodel and here some solutions to the problems identified there are proposed. Specifically, we evaluate the metamodel relating to stereotypes versus subtypes; the various kinds of Classifier (particularly Types, Interfaces and Classes); the introduction of a new subtype for the whole part relationship; as well as identifying areas in the metamodel where the UML seems to have been used inappropriately in the very definition of the UML's metamodel

931

Active vibration control of composite sandwich beams with piezoelectric extension-bending and shear actuators

We have used quasi-static equations of piezoelectricity to derive a finite element formulation capable of modelling two different kinds of piezoelastically induced actuation in an adaptive composite sandwich beam. This formulation is made to couple certain piezoelectric constants to a transverse electric field to develop extension-bending actuation and shear-induced actuation. As an illustration, we present a sandwich model of three sublaminates: face/core/face. We develop a control scheme based on the linear quadratic regulator/independent modal space control (LQR/IMSC) method and use this to estimate the active stiffness and the active damping introduced by shear and extension-bending actuators. To assess the performance of each type of actuator, a dynamic response study is carried out in the modal domain. We observe that the shear actuator is more efficient in actively controlling the vibration than the extension-bending actuator for the same control effort

974

Extrapolation in Lie groups with approximated BCH-formula

We present an extrapolation algorithm for the integration of differential equations in Lie groups which is a suitable generalization of the well-known GBS-algorithm for ODEs. Sufficiently accurate approximations to the BCH-formula are required to reach a given order. We give such approximations with a minimized number of commutators

137

An efficient DIPIE algorithm for CAD of electrostatically actuated MEMS devices

Pull-in parameters are important properties of electrostatic actuators. Efficient and accurate analysis tools that can capture these parameters for different design geometries, are therefore essential. Current simulation tools approach the pull-in state by iteratively adjusting the voltage applied across the actuator electrodes. The convergence rate of this scheme gradually deteriorates as the pull-in state is approached. Moreover, the convergence is inconsistent and requires many mesh and accuracy refinements to assure reliable predictions. As a result, the design procedure of electrostatically actuated MEMS devices can be time-consuming. In this paper a novel Displacement Iteration Pull-In Extraction (DIPIE) scheme is presented. The DIPIE scheme is shown to converge consistently and far more rapidly than the Voltage Iterations (VI) scheme (>100 times faster!). The DIPIE scheme requires separate mechanical and electrostatic field solvers. Therefore, it can be easily implemented in existing MOEMS CAD packages. Moreover, using the DIPIE scheme, the pull-in parameters extraction can be performed in a fully automated mode, and no user input for search bounds is required

989

A dynamic checkpoint scheduling scheme for fault tolerant distributed computing systems

The selection of the optimal checkpointing interval has been a very critical issue in implementing checkpointing-recovery schemes for fault tolerant distributed systems. This paper presents a new scheme that allows a process to select the proper checkpointing interval dynamically. A process in the system evaluates the cost of checkpointing and possible rollback for each checkpointing interval and selects the proper time interval for the next checkpointing. Unlike the other schemes, the overhead incurred by both the checkpointing and rollback activities are considered for the cost evaluation, and the current communication pattern is reflected in the selection of the checkpointing interval. Moreover, the proposed scheme requires no extra message communication for the checkpointing interval selection and can easily be incorporated into the existing checkpointing coordination schemes

98

Automating the compliance and supervision process

New technology enables large broker/dealers to supervise and ensure compliance across multiple branches and managers

898

Influence of advertising expenses on the characteristics of functioning of an insurance company

The basic characteristics of the functioning of an insurance company, including the average capital, ruin and survival probabilities, and the conditional time before ruin, are examined with allowance for advertising expenses

820

Yet some more complexity results for default logic

We identify several new tractable subsets and several new intractable simple cases for reasoning in the propositional version of Reiter's default logic. The majority of our findings are related to brave reasoning. By making some intuitive observations, most classes that we identify can be derived quite easily from some subsets of default logic already known in the literature. Some of the subsets we discuss are subclasses of the so-called "extended logic programs". All the tractable subsets presented in this paper can be recognized in linear time