Stabilization of positive systems with first integrals

Abstract: Positive systems possessing first integrals are considered. These systems frequently occur in applications. The paper is devoted to two stabilization problems. The first is concerned with the design of feedbacks to stabilize a given level set. Secondly, it is shown that the same feedback allows us to globally stabilize an equilibrium point if it is asymptotically stable with respect to initial conditions in its level set. Two examples are provided and the results are compared with those in the literature

positive systems
first integrals
feedbacks design
global stabilization
equilibrium point
asymptotic stability
chemical reactors


The dynamic aspect of land administration: an often-forgotten component in system design

Abstract: Although the establishment of a land administration system is enough of a challenge as it is, the task of keeping the system up to date with developments in society is even more challenging. Initial adjudication and cadastral mapping basically record land tenure as it exists at a given moment, i.e. the static situation. The paper aims to analyse the developments that might occur in a society with respect to tenure, value and use of land. These developments constitute a dynamic component of land administration. As land administration systems have to serve society on a long-term basis and normally have a long-term return on investment, the author recommends taking into account both the static and dynamic component when designing land administration systems

dynamic aspect
system design
land administration system
societal developments
adjudication
cadastral mapping
land tenure
static situation
return on investment
static component
dynamic component


Eliminating counterevidence with applications to accountable certificate management

Abstract: This paper presents a method to increase the accountability of certificate management by making it intractable for the certification authority (CA) to create contradictory statements about the validity of a certificate. The core of the method is a new primitive, undeniable attester, that allows someone to commit to some set S of bitstrings by publishing a short digest of S and to give attestations for any x that it is or is not a member of S. Such an attestation can be verified by obtaining in an authenticated way the published digest and applying a verification algorithm to the triple of the bitstring, the attestation and the digest. The most important feature of this primitive is the intractability of creating two contradictory proofs for the same candidate element x and digest. We give an efficient construction for undeniable attesters based on authenticated search trees. We show that the construction also applies to sets of more structured elements. We also show that undeniable attesters exist iff collision-resistant hash functions exist

counterevidence elimination
accountable certificate management
accountability
certification authority
undeniable attester primitive
attestations
published digest
verification algorithm
bitstring
contradictory proofs
authenticated search trees
structured elements
collision-resistant hash functions
long-term authenticity
non repudiation
public-key infrastructure
time-stamping


Even unimodular Gaussian lattices of rank 12

Abstract: We classify even unimodular Gaussian lattices of rank 12, that is, even unimodular integral lattices of rank 12 over the ring of Gaussian integers. This is equivalent to the classification of the automorphisms tau with tau /sup 2/=-1 in the automorphism groups of all the Niemeier lattices, which are even unimodular (real) integral lattices of rank 24. There are 28 even unimodular Gaussian lattices of rank 12 up to equivalence

even unimodular Gaussian lattices
even unimodular integral lattices
Gaussian integers
automorphisms
Niemeier lattices


The XML typechecking problem

Abstract: When an XML document conforms to a given type (e.g. a DTD or an XML schema type) it is called a valid document. Checking if a given XML document is valid is called the validation problem, and is typically performed by a parser (hence, validating parser), more precisely it is performed right after parsing, by the same program module. In practice however, XML documents are often generated dynamically, by some program: checking whether all XML documents generated by the program are valid WRT a given type is called the typechecking problem. While a validation analyzes an XML document, a type checker analyzes a program, and the problem's difficulty is a function of the language in which that program is expressed. The XML typechecking problem has been investigated recently and the XQuery Working Group adopted some of these techniques for typechecking XQuery. All these techniques, however, have limitations which need to be understood and further explored and investigated. We define the XML typechecking problem, and present current approaches to typechecking, discussing their limitations

XML typechecking problem
XML document
validation
XQuery


Module placement with boundary constraints using B*-trees

Abstract: The module placement problem is to determine the co-ordinates of logic modules in a chip such that no two modules overlap and some cost (e.g. silicon area, interconnection length, etc.) is optimised. To shorten connections between inputs and outputs and/or make related modules adjacent, it is desired to place some modules along the specific boundaries of a chip. To deal with such boundary constraints, we explore the feasibility conditions of a B*-tree with boundary constraints and develop a simulated annealing-based algorithm using B*-trees. Unlike most previous work, the proposed algorithm guarantees a feasible B*-tree with boundary constraints for each perturbation. Experimental results show that the algorithm can obtain a smaller silicon area than the most recent work based on sequence pairs

logic module placement
boundary constraints
B*-tree
simulated annealing algorithm
silicon area
interconnection length


Web ad explosion

Abstract: Financed by advertising dollars from big names, online marketers are embracing more aggressive tactics


Use of periodic and monotonic activation functions in multilayer feedforward neural networks trained by extended Kalman filter algorithm

Abstract: The authors investigate the convergence and pruning performance of multilayer feedforward neural networks with different types of neuronal activation functions in solving various problems. Three types of activation functions are adopted in the network, namely, the traditional sigmoid function, the sinusoidal function and a periodic function that can be considered as a combination of the first two functions. To speed up the learning, as well as to reduce the network size, the extended Kalman filter (EKF) algorithm conjunct with a pruning method is used to train the network. The corresponding networks are applied to solve five typical problems, namely, 4-point XOR logic function, parity generation, handwritten digit recognition, piecewise linear function approximation and sunspot series prediction. Simulation results show that periodic activation functions perform better than monotonic ones in solving multicluster classification problems. Moreover, the combined periodic activation function is found to possess the fast convergence and multicluster classification capabilities of the sinusoidal activation function while keeping the robustness property of the sigmoid function required in the modelling of unknown systems

multilayer feedforward neural networks
extended Kalman filter algorithm
monotonic activation functions
periodic activation functions
convergence
pruning performance
neuronal activation functions
sigmoid function
sinusoidal function
EKF algorithm
4-point XOR logic function
parity generation
handwritten digit recognition
piecewise linear function approximation
sunspot series prediction
multicluster classification problems


Generic simulation approach for multi-axis machining. Part 2: model calibration and feed rate scheduling

Abstract: For Part 1 see ibid. vol.124 (2002). This is the second part of a two-part paper presenting a new methodology for analytically simulating multi-axis machining of complex sculptured surfaces. The first section of this paper offers a detailed explanation of the model calibration procedure. A new methodology is presented for accurately determining the cutting force coefficients for multi-axis machining. The force model presented in Part 1 is reformulated so that the cutting force coefficients account for the effects of feed rate, cutting speed, and a complex cutting edge design. Experimental results are presented for the calibration procedure. Model verification tests were conducted with these cutting force coefficients. These tests demonstrate that the predicted forces are within 5% of experimentally measured forces. Simulated results are also shown for predicting dynamic cutting forces and static/dynamic tool deflection. The second section of the paper discusses how the modeling methodology can be applied for feed rate scheduling in an industrial application. A case study for process optimization of machining an airfoil-like surface is used for demonstration. Based on the predicted instantaneous chip load and/or a specified force constraint, the feed rate scheduling is utilized to increase the metal removal rate. The feed rate scheduling implementation results in a 30% reduction in machining time for the airfoil-like surface

multiple axis machining
generic simulation
model calibration
complex sculptured surfaces
cutting force coefficients
force model
cutting edge design
metal removal rate
optimization
feed rate scheduling


The semantic Web: differentiating between taxonomies and ontologies

Abstract: There is a new vision of the WWW - the semantic Web - that will dramatically improve Web-based services and products. It creates a setting where software agents perform everyday jobs for end-users. Deploying hierarchies, metadata, and structured vocabularies, the semantic Web expands basic Internet functions

WWW
semantic Web
software agents
hierarchies
metadata
structured vocabularies
Internet


Toward a formalism for conversation protocols using joint intention theory

Abstract: Conversation protocols are used to achieve certain goals or to bring about certain states in the world. Therefore, one may identify the landmarks or the states that must be brought about during the goal-directed execution of a protocol. Accordingly, the landmarks, characterized by propositions that are true in the state represented by that landmark, are the most important aspect of a protocol. Families of conversation protocols can be expressed formally as partially ordered landmarks after the landmarks necessary to achieve a goal have been identified. Concrete protocols represented as joint action expressions can, then, be derived from the partially ordered landmarks and executed directly by joint intention interpreters. This approach of applying Joint Intention theory to protocols also supports flexibility in the actions used to get to landmarks, shortcutting protocol execution, automatic exception handling, and correctness criterion for protocols and protocol compositions

conversation protocols
protocol execution
automatic exception handling
correctness criterion
multi-agent interactions
finite state machines


Minimised geometric Buchberger algorithm for integer programming

Abstract: Recently, various algebraic integer programming (IP) solvers have been proposed based on the theory of Grobner bases. The main difficulty of these solvers is the size of the Grobner bases generated. In algorithms proposed so far, large Grobner bases are generated by either introducing additional variables or by considering the generic IP problem IP/sub A,C/. Some improvements have been proposed such as Hosten and Sturmfels' method (GRIN) designed to avoid additional variables and Thomas' truncated Grobner basis method which computes the reduced Grobner basis for a specific IP problem IP/sub A,C/(b) (rather than its generalisation IPA,C). In this paper we propose a new algebraic algorithm for solving IP problems. The new algorithm, called Minimised Geometric Buchberger Algorithm, combines Hosten and Sturmfels' GRIN and Thomas' truncated Grobner basis method to compute the fundamental segments of an IP problem IP/sub A,C/ directly in its original space and also the truncated Grobner basis for a specific IP problem IP/sub A,C/ (b). We have carried out experiments to compare this algorithm with others such as the geometric Buchberger algorithm, the truncated geometric Buchberger algorithm and the algorithm in GRIN. These experiments show that the new algorithm offers significant performance improvement

minimised geometric Buchberger algorithm


One structure for fractional delay filter with small number of multipliers

Abstract: A wide-bandwidth, high-resolution fractional delay filter (FDF) structure with a small number of multipliers per output sample and a short coefficient computing time is presented. The proposal is based on the use of a frequency FDF design method up to only half of the Nyquist frequency, in a multirate structure

fractional delay filter
multipliers
wide-bandwidth filter
high-resolution filter
short coefficient computing time
multirate structure
finite impulse response filter
FIR filter
frequency domain design method


Max and min limiters

Abstract: If A contained in omega , n>or=2, and the function max({x/sub 1/,...,x/sub n/} intersection A) is partial recursive, it is easily seen that A is recursive. In this paper, we weaken this hypothesis in various ways (and similarly for "min" in place of "max") and investigate what effect this has on the complexity of A. We discover a sharp contrast between retraceable and co-retraceable sets, and we characterize sets which are the union of a recursive set and a co-r.e., retraceable set. Most of our proofs are noneffective. Several open questions are raised

min limiters
max limiters
complexity
retraceable sets
recursive set


The vibration reliability of poppet and contoured actuator valves

Abstract: The problem of selecting the shape of the actuator valve (the final control valve) itself is discussed; the solution to this problem will permit appreciable dynamic loads to be eliminated from the moving elements of the steam distribution system of steam turbines under all operating conditions

actuator valve shape selection
contoured actuator valves
poppet actuator valves
dynamic loads elimination
moving elements
steam distribution system
steam turbines
vibration reliability


Risk theory with a nonlinear dividend barrier

Abstract: In the framework of classical risk theory we investigate a surplus process in the presence of a nonlinear dividend barrier and derive equations for two characteristics of such a process, the probability of survival and the expected sum of discounted dividend payments. Number-theoretic solution techniques are developed for approximating these quantities and numerical illustrations are given for exponential claim sizes and a parabolic dividend barrier

risk theory
nonlinear dividend barrier
surplus process
probability of survival
discounted dividend payments
number-theoretic solution
numerical illustrations
exponential claim sizes
parabolic dividend barrier


Analysis of nonlinear time-delay systems using modules over non-commutative rings

Abstract: The theory of non-commutative rings is introduced to provide a basis for the study of nonlinear control systems with time delays. The left Ore ring of non-commutative polynomials defined over the field of a meromorphic function is suggested as the framework for such a study. This approach is then generalized to a broader class of nonlinear systems with delays that are called generalized Roesser systems. Finally, the theory is applied to analyze nonlinear time-delay systems. A weak observability is defined and characterized, generalizing the well-known linear result. Properties of closed submodules are then developed to obtain a result on the accessibility of such systems

nonlinear time-delay systems
modules
noncommutative rings
nonlinear control systems
left Ore ring
noncommutative polynomials
meromorphic function
generalized Roesser systems
weak observability


To commit or not to commit: modeling agent conversations for action

Abstract: Conversations are sequences of messages exchanged among interacting agents. For conversations to be meaningful, agents ought to follow commonly known specifications limiting the types of messages that can be exchanged at any point in the conversation. These specifications are usually implemented using conversation policies (which are rules of inference) or conversation protocols (which are predefined conversation templates). In this article we present a semantic model for specifying conversations using conversation policies. This model is based on the principles that the negotiation and uptake of shared social commitments entail the adoption of obligations to action, which indicate the actions that agents have agreed to perform. In the same way, obligations are retracted based on the negotiation to discharge their corresponding shared social commitments. Based on these principles, conversations are specified as interaction specifications that model the ideal sequencing of agent participations negotiating the execution of actions in a joint activity. These specifications not only specify the adoption and discharge of shared commitments and obligations during an activity, but also indicate the commitments and obligations that are required (as preconditions) or that outlive a joint activity (as postconditions). We model the Contract Net Protocol as an example of the specification of conversations in a joint activity

interacting agents
specifications
rules of inference
conversation protocols
autonomous agents
social commitments
speech acts
software agents
conversation templates


Mission planning for regional surveillance

Abstract: The regional surveillance problem discussed involves formulating a flight route for an aircraft to scan a given geographical region. Aerial surveillance is conducted using a synthetic aperture radar device mounted on the aircraft to compose a complete, high-resolution image of the region. Two models for determining an optimised flight route are described, the first employing integer programming and the second, genetic algorithms. A comparison of the solution optimality in terms of the total distance travelled, and model efficiency of the two techniques in terms of their required CPU times, is made in order to identify the conditions under which it is appropriate to apply each model

mission planning
regional surveillance
flight route
geographical region scanning
aerial surveillance
synthetic aperture radar device
high-resolution image
optimised flight route
integer programming
genetic algorithms
solution optimality
total distance travelled


SPARC ignites scholarly publishing

Abstract: During the past several years, initiatives which bring together librarians, researchers, university administrators and independent publishers have re-invigorated the scholarly publishing marketplace. These initiatives take advantage of electronic technology and show great potential for restoring science to scientists. The author outlines SPARC (the Scholarly Publishing and Academic Resources Coalition), an initiative to make scientific journals more accessible


Ant colony optimization and stochastic gradient descent

Abstract: We study the relationship between the two techniques known as ant colony optimization (ACO) and stochastic gradient descent. More precisely, we show that some empirical ACO algorithms approximate stochastic gradient descent in the space of pheromones, and we propose an implementation of stochastic gradient descent that belongs to the family of ACO algorithms. We then use this insight to explore the mutual contributions of the two techniques

ant colony optimization
stochastic gradient descent
empirical ACO algorithms
pheromones
combinatorial optimization
heuristic
reinforcement learning
social insects
swarm intelligence
artificial life
local search algorithms


Technology on social issues of videoconferencing on the Internet: a survey

Abstract: Constant advances in audio/video compression, the development of the multicast protocol as well as fast improvement in computing devices (e.g. higher speed, larger memory) have set forth the opportunity to have resource demanding videoconferencing (VC) sessions on the Internet. Multicast is supported by the multicast backbone (Mbone), which is a special portion of the Internet where this protocol is being deployed. Mbone VC tools are steadily emerging and the user population is growing fast. VC is a fascinating application that has the potential to greatly impact the way we remotely communicate and work. Yet, the adoption of VC is not as fast as one could have predicted. Hence, it is important to examine the factors that affect a widespread adoption of VC. This paper examines the enabling technology and the social issues. It discusses the achievements and identifies the future challenges. It suggests an integration of many emerging multimedia tools into VC in order to enhance its versatility for more effectiveness

videoconferencing
Internet
multicast protocol
multicast backbone
Mbone
multimedia
social issues
data compression


International news sites in English

Abstract: Web access to news sites all over the world allows us the opportunity to have an electronic news stand readily available and stocked with a variety of foreign (to us) news sites. A large number of currently available foreign sites are English-language publications or English language versions of non-North American sites. These sites are quite varied in terms of quality, coverage, and style. Finding them can present a challenge. Using them effectively requires critical-thinking skills that are a part of media awareness or digital literacy

Web access
international news sites
English-language publications
non North American sites
critical-thinking skills
media awareness
digital literacy


The paradigm of viral communication

Abstract: The IIW Institute of Information Management (www.IIW.de) is dealing with commercial applications of digital technologies, such as the Internet, digital printing, and many more. A study which has been carried out by the institute, identifies viral messages as a new paradigm of communication, mostly found in the area of Direct Marketing, and - who wonders - mainly within the USA. Viral messages underlie certain principles: (1) prospects and customers of the idea are offered a technology platform providing a possibility to send a message to a majority of persons; (2) there is an emotional or pecuniary incentive to participate. Ideally, niches of needs and market vacua are filled with funny ideas; (3) also, the recipients are facing emotional or pecuniary incentives to contact a majority of further recipients - this induces a snowball effect and the message is spread virally; and (4) the customer is activated as an "ambassador" of the piece of information, for instance promoting a product or a company. It is evident that there has been a long lasting history of what we call "word-of-mouth" ever since, however bundles of digital technologies empower the viral communication paradigm

viral communication paradigm
commercial applications
viral messages
e-mails
Internet
direct marketing
business
computer virus


Business data management for business-to-business electronic commerce

Abstract: Business-to-business electronic commerce (B2B EC) opens up new possibilities for trade. For example, new business partners from around the globe can be found, their offers can be compared, even complex negotiations can be conducted electronically, and a contract can be drawn up and fulfilled via an electronic marketplace. However, sophisticated data management is required to provide such facilities. In this paper, the results of a multi-national project on creating a business-to-business electronic marketplace for small and medium-sized enterprises are presented. Tools for information discovery, protocol-based negotiations, and monitored contract enactment are provided and based on a business data repository. The repository integrates heterogeneous business data with business communication. Specific problems such as multilingual nature, data ownership, and traceability of contracts and related negotiations are addressed and it is shown that the present approach provides efficient business data management for B2B EC


Multi-output regression using a locally regularised orthogonal least-squares algorithm

Abstract: The paper considers data modelling using multi-output regression models. A locally regularised orthogonal least-squares (LROLS) algorithm is proposed for constructing sparse multi-output regression models that generalise well. By associating each regressor in the regression model with an individual regularisation parameter, the ability of the multi-output orthogonal least-squares (OLS) model selection to produce a parsimonious model with a good generalisation performance is greatly enhanced


A systematic review of the efficacy of telemedicine for making diagnostic and management decisions

Abstract: We conducted a systematic review of the literature to evaluate the efficacy of telemedicine for making diagnostic and management decisions in three classes of application: office/hospital-based, store-and-forward, and home-based telemedicine. We searched the MEDLINE, EMBASE, CINAHL and HealthSTAR databases and printed resources, and interviewed investigators in the field. We excluded studies where the service did not historically require face-to-face encounters (e.g. radiology or pathology diagnosis). A total of 58 articles met the inclusion criteria. The articles were summarized and graded for the quality and direction of the evidence. There were very few high-quality studies. The strongest evidence for the efficacy of telemedicine for diagnostic and management decisions came from the specialties of psychiatry and dermatology. There was also reasonable evidence that general medical history and physical examinations performed via telemedicine had relatively good sensitivity and specificity. Other specialties in which some evidence for efficacy existed were cardiology and certain areas of ophthalmology. Despite the widespread use of telemedicine in most major medical specialties, there is strong evidence in only a few of them that the diagnostic and management decisions provided by telemedicine are comparable to face-to-face care

telemedicine
medical diagnosis
management decision making
literature review
MEDLINE
EMBASE
CINAHL
HealthSTAR
psychiatry
dermatology
cardiology
ophthalmology


Regularity of some 'incomplete' Pal-type interpolation problems

Abstract: In this paper the regularity of nine Pal-type interpolation problems is proved. In the literature interpolation on the zeros of the pair W/sub n//sup ( alpha )/(z) = (z + alpha )/sup n/ + (1 + alpha z)/sup n/, v/sub n//sup ( alpha )/(z) = (z + alpha )/sup n/ - (1 + alpha z)/sup n/ with 0 < alpha < 1 has been studied. Here the nodes form a subset of these sets of zeros


Solution of the reconstruction problem of a source function in the coagulation-fragmentation equation

Abstract: We study the problem of reconstructing a source function in the kinetic coagulation-fragmentation equation. The study is based on optimal control methods, the solvability theory of operator equations, and the use of iteration algorithms


Breaking the myths of rewards: an exploratory study of attitudes about knowledge sharing

Abstract: Many CEO and managers understand the importance of knowledge sharing among their employees and are eager to introduce the knowledge management paradigm in their organizations. However little is known about the determinants of the individual's knowledge sharing behavior. The purpose of this study is to develop an understanding of the factors affecting the individual's knowledge sharing behavior in the organizational context. The research model includes various constructs based on social exchange theory, self-efficacy, and theory of reasoned action. Research results from the field survey of 467 employees of four large, public organizations show that expected associations and contribution are the major determinants of the individual's attitude toward knowledge sharing. Expected rewards, believed by many to be the most important motivating factor for knowledge sharing, are not significantly related to the attitude toward knowledge sharing. As expected, positive attitude toward knowledge sharing is found to lead to positive intention to share knowledge and, finally, to actual knowledge sharing behaviors

knowledge sharing
knowledge management
social exchange theory
self-efficacy
theory of reasoned action
public organizations
rewards
strategic management


Technology in distance education: a global perspective to alternative delivery mechanisms

Abstract: Technology is providing a positive impact on delivery mechanisms employed in distance education at the university level. Some institutions are incorporating distance education as a way to extend the classroom. Other institutions are investigating new delivery mechanisms, which support a revised perspective on education. These latter institutions are revising their processes for interacting with students, and taking a more "learner centered" approach to the delivery of education. This article discusses the impact of technology on the delivery mechanisms employed in distance education. A framework is proposed here, which presents a description of alternative modes of generic delivery mechanisms. It is suggested that those institutions, which adopt a delivery mechanism employing an asynchronous mode, can gain the most benefit from technology. This approach seems to represent the only truly innovative use of technology in distance education. The approach creates a student-oriented environment while maintaining high levels of interaction, both of which are factors that contribute to student satisfaction with their overall educational experience

distance education
educational technology
university education
learner centered approach
student satisfaction
global perspective
asynchronous mode


Parallel operation of capacity-limited three-phase four-wire active power filters

Abstract: Three-phase four-wire active power filters (APFs) are presented that can be paralleled to enlarge the system capacity and reliability. The APF employs the PWM four-leg voltage-source inverter. A decoupling control approach for the leg connected to the neutral line is proposed such that the switching of all legs has no interaction. Functions of the proposed APF include compensation of reactive power, harmonic current, unbalanced power and zero-sequence current of the load. The objective is to achieve unity power factor, balanced line current and zero neutral-line current. Compensation of all components is capacity-limited, co-operating with the cascaded load current sensing scheme. Multiple APFs can be paralleled to share the load power without requiring any control interconnection. In addition to providing the theoretic bases and detailed design of the APFs, two 6 kVA APFs are implemented. The effectiveness of the proposed method is validated with experimental results


The perceived utility of human and automated aids in a visual detection task

Abstract: Although increases in the use of automation have occurred across society, research has found that human operators often underutilize (disuse) and overly rely on (misuse) automated aids (Parasuraman-Riley (1997)). Nearly 275 Cameron University students participated in 1 of 3 experiments performed to examine the effects of perceived utility (Dzindolet et al. (2001)) on automation use in a visual detection task and to compare reliance on automated aids with reliance on humans. Results revealed a bias for human operators to rely on themselves. Although self-report data indicate a bias toward automated aids over human aids, performance data revealed that participants were more likely to disuse automated aids than to disuse human aids. This discrepancy was accounted for by assuming human operators have a "perfect automation" schema. Actual or potential applications of this research include the design of future automated decision aids and training procedures for operators relying on such aids

automated aids
visual detection task
human operators
automated decision aids
social process
automation


Community spirit

Abstract: IT companies that contribute volunteers, resources or funding to charities and local groups not only make a real difference to their communities but also add value to their businesses. So says a new coalition of IT industry bodies formed to raise awareness of the options for community involvement, promote the business case, and publicise examples of best practice. The BCS, Intellect (formed from the merger of the Computing Services and Software Association and the Federation of the Electronics Industry) and the Worshipful Company of Information Technologists plan to run advisory seminars and provide guidelines on how companies of all sizes can transform their local communities using their specialist IT skills and resources while reaping business benefits

IT companies
volunteer staff
resource contribution
charity projects
community projects
staff development
business benefits
best practice


Midlife career choices: how are they different from other career choices?

Abstract: It was 1963 when Candy Start began working in libraries. Libraries seemed to be a refuge from change, a dependable environment devoted primarily to preservation. She was mistaken. Technological changes in every decade of her experience have affected how and where she used her MLS. Far from a static refuge, libraries have proven to be spaceships loaded with precious cargo hurtling into the unknown. The historian in the author says that perhaps libraries have always been like this. This paper looks at a midlife decision point and the choice that this librarian made to move from a point of lessening productivity and interest to one of increasing challenge and contribution. It is a personal narrative of midlife experience from one librarian's point of view. Since writing this article, Candy's career has followed more changes. After selling the WINGS TM system, she has taken her experiences and vision to another library vendor, Gaylord Information Systems, where she serves as a senior product strategist

midlife career choices
libraries
technological changes
productivity


Structural interpretation of matched pole-zero discretisation

Abstract: Deals with matched pole-zero discretisation, which has been used in practice for hand calculations in the digital redesign of continuous-time systems but available only in the transfer-function form. Since this form is inconvenient for characterising the time-domain properties of sampled-data loops and for computerising the design of such systems, a state-space formulation is developed. Under the new interpretation, the matched pole-zero model is shown to be structurally identical to a hold-equivalent discrete-time model, where the generalised hold takes integral part, thus unifying the most widely used discretisation approaches. An algorithm for obtaining the generalised hold function is presented. The hold-equivalent structure of the matched pole-zero model clarifies several discrete-time system properties, such as controllability and observability, and their preservation or loss with a matched pole-zero discretisation. With the proposed formulation, the matched pole-zero, hold-equivalent, and mapping models can now all be constructed with a single schematic model

structural interpretation
matched pole-zero discretisation
continuous-time systems
time-domain properties
sampled-data loops
state-space formulation
hold-equivalent discrete-time model
controllability
observability
closed-loop system
digital simulations


The diameter of a long-range percolation graph

Abstract: We consider the following long-range percolation model: an undirected graph with the node set {0, 1, . . . , N}/sup d/, has edges (x, y) selected with probability approximately= beta /||x - y||/sup s/ if ||x - y|| > 1, and with probability 1 if ||x - y|| = 1, for some parameters beta , s > 0. This model was introduced by who obtained bounds on the diameter of this graph for the one-dimensional case d = 1 and for various values of s, but left cases s = 1, 2 open. We show that, with high probability, the diameter of this graph is Theta (log N/log log N) when s = d, and, for some constants 0 < eta /sub 1/ < eta /sub 2/ < 1, it is at most N/sup eta 2/ when s = 2d, and is at least N/sup eta 1/ when d = 1, s = 2, beta < 1 or when s > 2d. We also provide a simple proof that the diameter is at most log/sup O(1)/ N with high probability, when d < s < 2d, established previously in Benjamini and Berger (2001)

long-range percolation model
undirected graph
probability
percolation
positive probability
networks
random graph


Component support in PLT scheme

Abstract: PLT Scheme (DrScheme and MzScheme) supports the Component Object Model (COM) standard with two pieces of software. The first piece is MzCOM, a COM class that makes a Scheme evaluator available to COM clients. With MzCOM, programmers can embed Scheme code in programs written in mainstream languages such as C++ or Visual BASIC. Some applications can also be used as MzCOM clients. The other piece of component-support software is MysterX, which makes COM classes available to PLT Scheme programs. When needed, MysterX uses a programmable Web browser to display COM objects. We describe the technical issues encountered in building these two systems and sketch some applications

PLT Scheme
Component Object Model
MzCOM
reuse
Web browser


Wavelet collocation methods for a first kind boundary integral equation in acoustic scattering

Abstract: In this paper we consider a wavelet algorithm for the piecewise constant collocation method applied to the boundary element solution of a first kind integral equation arising in acoustic scattering. The conventional stiffness matrix is transformed into the corresponding matrix with respect to wavelet bases, and it is approximated by a compressed matrix. Finally, the stiffness matrix is multiplied by diagonal preconditioners such that the resulting matrix of the system of linear equations is well conditioned and sparse. Using this matrix, the boundary integral equation can be solved effectively

first kind integral operators
piecewise constant collocation
wavelet algorithm
boundary element solution
boundary integral equation
wavelet transform
computational complexity
acoustic scattering
stiffness matrix
linear equations


Exact frequency-domain reconstruction for thermoacoustic tomography. II. Cylindrical geometry

Abstract: For pt. I see ibid., vol. 21, no. 7, p. 823-8 (2002). Microwave-induced thermoacoustic tomography (TAT) in a cylindrical configuration is developed to image biological tissue. Thermoacoustic signals are acquired by scanning a flat ultrasonic transducer. Using a new expansion of a spherical wave in cylindrical coordinates, we apply the Fourier and Hankel transforms to TAT and obtain an exact frequency-domain reconstruction method. The effect of discrete spatial sampling on image quality is analyzed. An aliasing-proof reconstruction method is proposed. Numerical and experimental results are included

medical diagnostic imaging
frequency-domain reconstruction
flat ultrasonic transducer
thermoacoustic tomography
cylindrical geometry
discrete spatial sampling effect
ultrasound imaging
spherical wave expansion
aliasing-proof reconstruction method
Hankel transform


An eight-year study of Internet-based remote medical counselling

Abstract: We carried out a prospective study of an Internet-based remote counselling service. A total of 15,456 Internet users visited the Web site over eight years. From these, 1500 users were randomly selected for analysis. Medical counselling had been granted to 901 of the people requesting it (60%). One hundred and sixty-four physicians formed project groups to process the requests and responded using email. The distribution of patients using the service was similar to the availability of the Internet: 78% were from the European Union, North America and Australia. Sixty-seven per cent of the patients lived in urban areas and the remainder were residents of remote rural areas with limited local medical coverage. Sixty-five per cent of the requests were about problems of internal medicine and 30% of the requests concerned surgical issues. The remaining 5% of the patients sought information about recent developments, such as molecular medicine or aviation medicine. During the project, our portal became inaccessible five times, and counselling was not possible on 44 days. There was no hacking of the Web site. Internet-based medical counselling is a helpful addition to conventional practice


Meeting of minds

Abstract: Technical specialists need to think about their role in IT projects and how they communicate with end-users and other participants to ensure they contribute fully as team members. It is especially important to communicate and document trade-offs that may have to be made, including the rationale behind them, so that if requirements change, the impact and decisions can be readily communicated to the stakeholders

technical specialists
IT projects
communication
end-users


Are we there yet?: facing the never-ending speed and change of technology in midlife

Abstract: This essay is a personal reflection on entering librarianship in middle age at a time when the profession, like society in general, is experiencing rapidly accelerating change. Much of this change is due to the increased use of computers and information technologies in the library setting. These aids in the production, collection, storage, retrieval, and dissemination of the collective information, knowledge, and sometimes wisdom of the past and the contemporary world can exhilarate or burden depending on one's worldview, the organization, and the flexibility of the workplace. This writer finds herself working in a library where everyone is expected continually to explore and use new ways of working and providing library service to a campus and a wider community. No time is spent in reflecting on what was, but all efforts are to anticipate and prepare for what will be

librarianship
middle age
changing technology
computers
information technologies
dissemination
retrieval
storage
collection


Resolving Web user on the fly

Abstract: Identity authentication systems and procedures are rapidly becoming central issues in the practice and study of information systems development and security. Requirements for Web transaction security (WTS) include strong authentication of a user, non-repudiation and encryption of all traffic. In this paper, we present an effective mechanism involving two different channels, which addresses the prime concerns involved in the security of electronic commerce transactions (ECT) viz. user authentication and non-repudiation. Although the product is primarily targeted to provide a fillip to transactions carried out over the Web, this product can also be effectively used for non-Internet transactions that are carried out where user authentication is required

identity authentication systems
information systems development
information systems security
Web transaction security
nonrepudiation
encryption
traffic
electronic commerce transactions


Contrast sensitivity in a dynamic environment: effects of target conditions and visual impairment

Abstract: Contrast sensitivity was determined as a function of target velocity (0 degrees -120 degrees /s) over a variety of viewing conditions. In Experiment 1, measurements of dynamic contrast sensitivity were determined for observers as a function of target velocity for letter stimuli. Significant main effects were found for target velocity, target size, and target duration, but significant interactions among the variables indicated especially pronounced adverse effects of increasing target velocity for small targets and brief durations. In Experiment 2, the effects of simulated cataracts were determined. Although the simulated impairment had no effect on traditional acuity scores, dynamic contrast sensitivity was markedly reduced. Results are discussed in terms of dynamic contrast sensitivity as a useful composite measure of visual functioning that may provide a better overall picture of an individual's visual functioning than does traditional static acuity, dynamic acuity, or contrast sensitivity alone. The measure of dynamic contrast sensitivity may increase understanding of the practical effects of various conditions, such as aging or disease, on the visual system, or it may allow improved prediction of individuals' performance in visually dynamic situations

contrast sensitivity
dynamic environment
target conditions
visual impairment
dynamic contrast sensitivity
target velocity
target size
target duration
acuity scores
aging
disease


Medical image computing at the Institute of Mathematics and Computer Science in Medicine, University Hospital Hamburg-Eppendorf

Abstract: The author reviews the history of medical image computing at his institute, summarizes the achievements, sketches some of the difficulties encountered, and draws conclusions that might be of interest especially to people new to the field. The origin and history section provides a chronology of this work, emphasizing the milestones reached during the past three decades. In accordance with the author's group's focus on imaging, the paper is accompanied by many pictures, some of which, he thinks, are of historical value


An interactive self-replicator implemented in hardware

Abstract: Self-replicating loops presented to date are essentially worlds unto themselves, inaccessible to the observer once the replication process is launched. We present the design of an interactive self-replicating loop of arbitrary size, wherein the user can physically control the loop's replication and induce its destruction. After introducing the BioWall, a reconfigurable electronic wall for bio-inspired applications, we describe the design of our novel loop and delineate its hardware implementation in the wall

interactive self-replicator
interactive self-replicating loop
BioWall
reconfigurable electronic wall
bio-inspired applications
hardware implementation
self-replication
field programmable gate array
cellular automata
reconfigurable computing
artificial life


Document-based workflow modeling: a case-based reasoning approach

Abstract: A workflow model is useful for business process analysis. A well-built workflow can help a company streamline its internal processes by reducing overhead. The results of workflow modeling need to be managed as information assets in a systematic fashion. Reusing these results is likely to enhance the quality of the modeling. Therefore, this paper proposes a document-based workflow modeling mechanism, which employs a case-based reasoning (CBR) technique for the effective reuse of design outputs. A repository is proposed to support this CBR process. A real-life case is illustrated to demonstrate the usefulness of our approach

document-based workflow modeling
case-based reasoning
business process analysis
company
information assets
design output reuse


On the expected value of the minimum assignment

Abstract: The minimum k-assignment of an m*n matrix X is the minimum sum of k entries of X, no two of which belong to the same row or column. Coppersmith and Sorkin conjectured that if X is generated by choosing each entry independently from the exponential distribution with mean 1, then the expected value of its minimum k-assignment is given by an explicit formula, which has been proven only in a few cases. In this paper we describe our efforts to prove the Coppersmith-Sorkin conjecture by considering the more general situation where the entries x/sub ij/ of X are chosen independently from different distributions. In particular, we require that x/sub ij/ be chosen from the exponential distribution with mean 1/r/sub i/c/sub j/. We conjecture an explicit formula for the expected value of the minimum k-assignment of such X and give evidence for this formula

minimum k-assignment
m * n matrix
exponential distribution
rational function
bipartite graph


Integrated process control using an in situ sensor for etch

Abstract: The migration to tighter geometries and more complex process sequence integration schemes requires having the ability to compensate for upstream deviations from target specifications. Doing so ensures that-downstream process sequences operate on work-in-progress that is well within control. Because point-of-use visibility of work-in-progress quality has become of paramount concern in the industry's drive to reduce scrap and improve yield, controlling trench depth has assumed greater importance. An integrated, interferometric based, rate monitor for etch-to-depth and spacer etch applications has been developed for controlling this parameter. This article demonstrates that the integrated rate monitor, using polarization and digital signal processing, enhances control etch-to-depth processes and can also be implemented as a predictive endpoint in a wafer manufacturing environment for dual damascene trench etch and spacer etch applications


Training multilayer perceptrons via minimization of sum of ridge functions

Abstract: Motivated by the problem of training multilayer perceptrons in neural networks, we consider the problem of minimizing E(x)= Sigma /sub i=1//sup n/ f/sub i/( xi /sub i/.x), where xi /sub i/ in R/sup S/, 1<or=i<or=n, and each f/sub i/( xi /sub i/.x) is a ridge function. We show that when n is small the problem of minimizing E can be treated as one of minimizing univariate functions, and we use the gradient algorithms for minimizing E when n is moderately large. For a large n, we present the online gradient algorithms and especially show the monotonicity and weak convergence of the algorithms

multilayer perceptrons
online gradient algorithms
ridge functions
minimization
neural networks
gradient algorithms
univariate functions
monotonicity
weak convergence


Elastic constraint branching, the Wedelin/Carmen Lagrangian heuristic and integer programming for personnel scheduling

Abstract: The Wedelin algorithm is a Lagrangian based heuristic that is being successfully used by Carmen Systems to solve large crew pairing problems within the airline industry. We extend the Wedelin approach by developing an implementation for personnel scheduling problems (also termed staff rostering problems) that exploits the special structure of these problems. We also introduce elastic constraint branching with the twin aims of improving the performance of our new approach and making it more column generation friendly. Numerical results show that our approach can outperform the commercial solver CPLEX on difficult commercial rostering problems

elastic constraint branching
integer programming
personnel scheduling
Wedelin algorithm
Lagrangian based heuristic
Carmen Systems
large crew pairing problems
airline industry
staff rostering problems
column generation friendly approach


An empirical investigation of the influences of the degree of interactivity on user-outcomes in a multimedia environment

Abstract: The study reported here investigates the influence of "interactivity" on the learning outcomes of users in a multimedia systems environment. Drawing from past literature base and based on key tenets of three learning theories - behaviorist, cognitivist, and constructivist - the study first proposes a measurement scheme for "interactivity" and then hypothesizes that "interactivity" would influence the learning outcomes positively in terms of users' learning achievement and attitude. Three prototypes of a multimedia instructional/training system to represent high, low, and noninteractive modes of use were developed and implemented and the hypothesized influences were investigated using a controlled laboratory research design. Multiple analysis of variance (MANOVA) results indicate that while interactivity does not necessarily enable enhanced gain in user learning, it positively influences participants' attitude. The study finds no support for hypothesized moderating effects of learning styles (measured using Kolb's Learning Style Inventory scale) on the relationship between interactivity and user outcomes. The results of this study have important implications for both education and corporations' training efforts and investments. Implications and future research directions are discussed

interactivity
user outcomes
learning outcomes
behaviorist learning theories
cognitivist learning theories
constructivist learning theories
measurement scheme
user attitude
training system
multiple analysis of variance
MANOVA
Kolb Learning Style Inventory scale
education
corporations
multimedia systems environment


Dynamic multi-objective heating optimization

Abstract: We develop a multicriteria approach to the problem of space heating under a time varying price of electricity. In our dynamic goal programming model the goals are ideal temperature intervals and the other criteria are the costs and energy consumption. We discuss the modelling requirements in multicriteria problems with a dynamic structure and present a new relaxation method combining the traditional epsilon -constraint and goal programming (GP) methods. The multi-objective heating optimization (MOHO) application in a spreadsheet environment with numerical examples is described

dynamic multi-objective heating optimization


Dual nature of mass multi-agent systems

Abstract: Dual nature of mass multi-agent systems (mMAS) emerging as an internal discord of two spheres - micro (virtual) consisting of agents and their internal phenomena, and macro arising at the interface to the real world $stems the necessity of a new approach to analysis, design and utilisation of such systems. Based on the concept of VR decomposition, the problem of management of such systems is discussed. As a sub-type that makes mMAS closer to the application sphere, an evolutionary multi-agent system (EMAS) is proposed. EMAS combines features of mMAS with advantages of an evolutionary model of computation. As an illustration of this consideration two particular EMAS are presented, which allow us to obtain promising results in the fields of multiobjective optimisation and time-series prediction, and thus justify the approach

mass multiple agent systems
VR decomposition
virtual reality
multiobjective optimisation
time-series prediction
micro-macro link
formal model
evolutionary multiple agent system


Differential calculus for p-norms of complex-valued vector functions with applications

Abstract: For complex-valued n-dimensional vector functions t to s(t), supposed to be sufficiently smooth, the differentiability properties of the mapping t to ||s(t)||/sub p/ at every point t = t/sub 0/ epsilon R/sub 0//sup +/:= {t epsilon R | t >or= 0} are investigated, where || . ||/sub p/ is the usual vector norm in C/sup n/ resp. R/sup n/, for p epsilon [1, o infinity ]. Moreover, formulae for the first three right derivatives D/sub +//sup k/||s(t)||/sub p/, k = 1, 2,3 are determined. These formulae are applied to vibration problems by computing the best upper bounds on ||s(t)||/sub p/ in certain classes of bounds. These results cannot be obtained by the methods used so far. The systematic use of the differential calculus for vector norms, as done here for the first time, could lead to major advances also in other branches of mathematics and other sciences

differential calculus
vector functions
mapping
vibration problems
vector norms


Efficient algorithms for stiff elliptic problems with large parameters

Abstract: We consider a finite element approximation and iteration algorithms for solving stiff elliptic boundary value problems with large parameters in front of a higher derivative. The convergence rate of the algorithms is independent of the spread in coefficients and a discretization parameter

finite element approximation
iteration algorithms
stiff elliptic boundary value problems
large parameters
higher derivative
efficient algorithms
convergence rate


Information systems project failure: a comparative study of two countries

Abstract: Many organizations, regardless of size, engage in at least one, and often many information system projects each year. Many of these projects consume massive amounts of resources, and may cost as little as a few thousand dollars to ten, and even hundreds of millions of dollars. Needless to say, the investment of time and resources into these ventures are of significant concern to chief information officers (CIOs), executives staff members, project managers, and others in leadership positions. This paper describes the results of a survey performed between Australia and the United States regarding factors leading to IS project failure. The findings suggest that, among other things, end user involvement and executive management leadership are key indicators influencing IS project failure

information systems project failure
Australia
United States
end user involvement
executive management leadership


Modeling shape and topology of low-resolution density maps of biological macromolecules

Abstract: We develop an efficient way of representing the geometry and topology of volumetric datasets of biological structures from medium to low resolution, aiming at storing and querying them in a database framework. We make use of a new vector quantization algorithm to select the points within the macromolecule that best approximate the probability density function of the original volume data. Connectivity among points is obtained with the use of the alpha shapes theory. This novel data representation has a number of interesting characteristics, such as (1) it allows us to automatically segment and quantify a number of important structural features from low-resolution maps, such as cavities and channels, opening the possibility of querying large collections of maps on the basis of these quantitative structural features; (2) it provides a compact representation in terms of size; (3) it contains a subset of three-dimensional points that optimally quantify the densities of medium resolution data; and (4) a general model of the geometry and topology of the macromolecule (as opposite to a spatially unrelated bunch of voxels) is easily obtained by the use of the alpha shapes theory

geometry
topology
volumetric datasets
biological structures
database framework
vector quantization algorithm
low-resolution density maps
biological macromolecules
modeling
probability density function
data representation
structural features
cavities
channels
connectivity
compact representation
three-dimensional points
medium resolution data
general model
original volume data
alpha shapes theory

P P P P P P P P P P P P P P P P P P P P P


On a general constitutive description for the inelastic and failure behavior of fibrous laminates. I. Lamina theory

Abstract: It is well known that a structural design with isotropic materials can only be accomplished based on a stress failure criterion. This is, however, generally not true with laminated composites. Only when the laminate is subjected to an in-plane load, can the ultimate failure of the laminate correspond to its last-ply failure, and hence a stress failure criterion may be sufficient to detect the maximum load that can be sustained by the laminate. Even in such a case, the load shared by each lamina in the laminate cannot be correctly determined if the lamina instantaneous stiffness matrix is inaccurately provided, since the lamina is always statically indeterminate in the laminate. If, however, the laminate is subjected to a lateral load, its ultimate failure occurs before last-ply failure and use of the stress failure criterion is no longer sufficient; an additional critical deflection or curvature condition must also be employed. This necessitates development of an efficient constitutive relationship for laminated composites in order that the laminate strains/deflections up to ultimate failure can be accurately calculated. A general constitutive description for the thermomechanical response of a fibrous laminate up to ultimate failure with applications to various fibrous laminates is presented in the two papers. The constitutive relationship is obtained by combining classical lamination theory with a recently developed bridging micromechanics model, through a layer-by-layer analysis. This paper focuses on lamina analysis

general constitutive description
inelastic behavior
failure behavior
fibrous laminates
lamina theory
structural design
isotropic materials
stress failure criterion
in-plane load
instantaneous stiffness matrix
lateral load
last-ply failure
critical deflection condition
critical curvature condition
composites
laminate strains
laminate deflections
thermomechanical response
layer-by-layer analysis
micromechanics model
multidirectional tape laminae
woven fabric composites
braided fabric composites
knitted fabric reinforced composites
elastoplasticity
elastic-viscoplasticity

P R P P P P P P P P P P R R P M R P P P M M M M U U


Self-reproduction in three-dimensional reversible cellular space

Abstract: Due to inevitable power dissipation, it is said that nano-scaled computing devices should perform their computing processes in a reversible manner. This will be a large problem in constructing three-dimensional nano-scaled functional objects. Reversible cellular automata (RCA) are used for modeling physical phenomena such as power dissipation, by studying the dissipation of garbage signals. We construct a three-dimensional self-inspective self-reproducing reversible cellular automaton by extending the two-dimensional version SR/sub 8/. It can self-reproduce various patterns in three-dimensional reversible cellular space without dissipating garbage signals

3D self-inspective self-reproducing cellular automata


Hot controllers

Abstract: Over the last few years, the semiconductor industry has put much emphasis on ways to improve the accuracy of thermal mass flow controllers (TMFCs). Although issues involving TMFC mounting orientation and pressure effects have received much attention, little has been done to address the effect of changes in ambient temperature or process gas temperature. Scientists and engineers at Qualiflow have succeeded to solve the problem using a temperature correction algorithm for digital TMFCs. Using an in situ environmental temperature compensation technique, we calculated correction factors for the temperature effect and obtained satisfactory results with both the traditional sensor and the new, improved thin-film sensors


Taming the paper tiger [paperwork organization]

Abstract: Generally acknowledged as a critical problem for many information professionals, the massive flow of documents, paper trails, and information needs efficient and dependable approaches for processing and storing and finding items and information

paperwork organization
information professionals
information processing
information storage
information retrieval


Cane railway scheduling via constraint logic programming: labelling order and constraints in a real-life application

Abstract: In Australia, cane transport is the largest unit cost in the manufacturing of raw sugar, making up around 35% of the total manufacturing costs. Producing efficient schedules for the cane railways can result in significant cost savings. The paper presents a study using constraint logic programming (CLP) to solve the cane transport scheduling problem. Tailored heuristic labelling order and constraints strategies are proposed and encouraging results of application to several test problems and one real-life case are presented. The preliminary results demonstrate that CLP can be used as an effective tool for solving the cane transport scheduling problem, with a potential decrease in development costs of the scheduling system. It can also be used as an efficient tool for rescheduling tasks which the existing cane transport scheduling system cannot perform well

cane railway scheduling
constraint logic programming
cane transport
raw sugar
total manufacturing costs
cost savings
heuristic labelling order
constraints strategies


Maple 8 keeps everyone happy

Abstract: The author is impressed with the upgrade to the mathematics package Maple 8, finding it genuinely useful to scientists and educators. The developments Waterloo Maple class as revolutionary include a student calculus package, and Maplets. The first provides a high-level command set for calculus exploration and plotting (removing the need to work with, say, plot primitives). The second is a package for hand-coding custom graphical user interfaces (GUIs) using elements such as check boxes, radio buttons, slider bars and pull-down menus. When called, a Maplet launches a runtime Java environment that pops up a window-analogous to a Java applet-to perform a programmed routine, if required passing the result back to the Maple worksheet

Maple 8 mathematics package
student calculus package
high-level command set
calculus exploration
calculus plotting
GUIs
Maplet
runtime Java environment


Maintaining e-commerce

Abstract: E-commerce over the Web has created a relatively new type of information system. So it is hardly surprising that little attention has been given to the maintenance of such systems-and even less to attempting to develop them with future maintenance in mind. But there are various ways e-commerce systems can be developed to reduce future maintenance

e-commerce systems maintenance
Web systems


Conceptual modeling and specification generation for B2B business processes based on ebXML

Abstract: In order to support dynamic setup of business processes among independent organizations, a formal standard schema for describing the business processes is basically required. The ebXML framework provides such a specification schema called BPSS (Business Process Specification Schema) which is available in two standalone representations: a UML version, and an XML version. The former, however, is not intended for the direct creation of business process specifications, but for defining specification elements and their relationships required for creating an ebXML-compliant business process specification. For this reason, it is very important to support conceptual modeling that is well organized and directly matched with major modeling concepts. This paper deals with how to represent and manage B2B business processes using UML-compliant diagrams. The major challenge is to organize UML diagrams in a natural way that is well suited to the business process meta-model and then to transform the diagrams into an XML version. This paper demonstrates the usefulness of conceptually modeling business processes by prototyping a business process editor tool called ebDesigner

B2B business processes
ebXML
conceptual modeling
specification generation
formal standard schema
Business Process Specification Schema
UML-compliant diagrams
meta model
ebDesigner
business process editor


Novel TCP congestion control scheme and its performance evaluation

Abstract: A novel self-tuning proportional and derivative (ST-PD) control based TCP congestion control scheme is proposed. The new scheme approaches the congestion control problem from a control-theoretical perspective and overcomes several Important limitations associated with existing TCP congestion control schemes, which are heuristic based. In the proposed scheme, a PD controller is employed to keep the buffer occupancy of the bottleneck node on the connection path at an ideal operating level, and it adjusts the TCP window accordingly. The control gains of the PD controller are tuned online by a fuzzy logic controller based on the perceived bandwidth-delay product of the TCP connection. This scheme gives ST-PD TCP several advantages over current TCP implementations. These include rapid response to bandwidth variations, insensitivity to buffer sizes, and significant improvement of TCP throughput over lossy links by decoupling congestion control and error control functions of TCP


Client satisfaction in a feasibility study comparing face-to-face interviews with telepsychiatry

Abstract: We carried out a pilot study comparing satisfaction levels between psychiatric patients seen face to face (FTF) and those seen via videoconference. Patients who consented were randomly assigned to one of two groups. One group received services in person (FTF from the visiting psychiatrist) while the other was seen using videoconferencing at 128 kbit/s. One psychiatrist provided all the FTF and videoconferencing assessment and follow-up visits. A total of 24 subjects were recruited. Three of the subjects (13%) did not attend their appointments and two subjects in each group were lost to follow-up. Thus there were nine in the FTF group and eight in the videoconferencing group. The two groups were similar in most respects. Patient satisfaction with the services was assessed using the Client Satisfaction Questionnaire (CSQ-8), completed four months after the initial consultation. The mean scores were 25.3 in the FTF group and 21.6 in the videoconferencing group. Although there was a trend in favour of the FTF service, the difference was not significant. Patient satisfaction is only one component of evaluation. The efficacy of telepsychiatry must also be measured relative to that of conventional, FTF care before policy makers can decide how extensively telepsychiatry should be implemented

client satisfaction
face-to-face interviews
telepsychiatry
psychiatric patient satisfaction
human factors
videoconference
Client Satisfaction Questionnaire
telemedicine
128 kbit/s


The pedagogy of on-line learning: a report from the University of the Highlands and Islands Millennium Institute

Abstract: Authoritative sources concerned with computer-aided learning, resource-based learning and on-line learning and teaching are generally agreed that, in addition to subject matter expertise and technical support, the quality of the learning materials and the learning experiences of students are critically dependent on the application of pedagogically sound theories of learning and teaching and principles of course design. The University of the Highlands and Islands Project (UHIMI) is developing "on-line learning" on a large scale. These developments have been accompanied by a comprehensive programme of staff development. A major emphasis of the programme is concerned with ensuring that course developers and tutors are pedagogically aware. This paper reviews (i) what is meant by "on-line learning" in the UHIMI context (ii) the theories of learning and teaching and principles of course design that inform the staff development programme and (iii) a review of progress to date


Doubly invariant equilibria of linear discrete-time games

Abstract: The notion of doubly invariant (DI) equilibrium is introduced. The concept extends controlled and robustly controlled invariance notions to the context of two-person dynamic games. Each player tries to keep the state in a region of state space independently of the actions of the rival player. The paper gives existence conditions, criteria and algorithms for the determination of DI equilibria of linear dynamic games in discrete time. Two examples illustrate the results. The first one is in the area of fault-tolerant controller synthesis. The second is an application to macroeconomics

doubly invariant equilibria
linear discrete-time games
robustly controlled invariance
two-person dynamic games
state space
existence conditions
fault-tolerant controller synthesis
macroeconomics


Hordes: a multicast based protocol for anonymity

Abstract: With widespread acceptance of the Internet as a public medium for communication and information retrieval, there has been rising concern that the personal privacy of users can be eroded by cooperating network entities. A technical solution to maintaining privacy is to provide anonymity. We present a protocol for initiator anonymity called Hordes, which uses forwarding mechanisms similar to those used in previous protocols for sending data, but is the first protocol to make use of multicast routing to anonymously receive data. We show this results in shorter transmission latencies and requires less work of the protocol participants, in terms of the messages processed. We also present a comparison of the security and anonymity of Hordes with previous protocols, using the first quantitative definition of anonymity and unlinkability. Our analysis shows that Hordes provides anonymity in a degree similar to that of Crowds and Onion Routing, but also that Hordes has numerous performance advantages

Hordes
protocol
Internet
personal privacy
cooperating network entities
initiator anonymity
forwarding mechanisms
multicast routing
transmission latencies
unlinkability
Crowds
Onion Routing
performance


An adaptive time step procedure for a parabolic problem with blow-up

Abstract: In this paper we introduce and analyze a fully discrete approximation for a parabolic problem with a nonlinear boundary condition which implies that the solutions blow up in finite time. We use standard linear elements with mass lumping for the space variable. For the time discretization we write the problem in an equivalent form which is obtained by introducing an appropriate time re-scaling and then, we use explicit Runge-Kutta methods for this equivalent problem. In order to motivate our procedure we present it first in the case of a simple ordinary differential equation and show how the blow up time is approximated in this case. We obtain necessary and sufficient conditions for the blowup of the numerical solution and prove that the numerical blow-up time converges to the continuous one. We also study, for the explicit Euler approximation, the localization of blow-up points for the numerical scheme

adaptive time step procedure
parabolic problem
fully discrete approximation
nonlinear boundary condition
standard linear elements
Runge-Kutta methods
explicit Euler approximation


Modeling undesirable factors in efficiency evaluation

Abstract: Data envelopment analysis (DEA) measures the relative efficiency of decision making units (DMUs) with multiple performance factors which are grouped into outputs and inputs. Once the efficient frontier is determined, inefficient DMUs can improve their performance to reach the efficient frontier by either increasing their current output levels or decreasing their current input levels. However, both desirable (good) and undesirable (bad) factors may be present. For example, if inefficiency exists in production processes where final products are manufactured with a production of wastes and pollutants, the outputs of wastes and pollutants are undesirable and should be reduced to improve the performance. Using the classification invariance property, we show that the standard DEA model can be used to improve the performance via increasing the desirable outputs and decreasing the undesirable outputs. The method can also be applied to situations when some inputs need to be increased to improve the performance. The linearity and convexity of DEA are preserved through our proposal

data envelopment analysis
decision making units
multiple performance factors
efficient frontier
current output levels
current input levels
production processes
final product manufacture
wastes
pollutants
classification invariance property
desirable outputs
undesirable outputs
linear programming
efficiency evaluation
undesirable factor modeling


Trends in agent communication language

Abstract: Agent technology is an exciting and important new way to create complex software systems. Agents blend many of the traditional properties of AI programs - knowledge-level reasoning, flexibility, proactiveness, goal-directedness, and so forth - with insights gained from distributed software engineering, machine learning, negotiation and teamwork theory, and the social sciences. An important part of the agent approach is the principle that agents (like humans) can function more effectively in groups that are characterized by cooperation and division of labor. Agent programs are designed to autonomously collaborate with each other in order to satisfy both their internal goals and the shared external demands generated by virtue of their participation in agent societies. This type of collaboration depends on a sophisticated system of inter-agent communication. The assumption that inter-agent communication is best handled through the explicit use of an agent communication language (ACL) underlies each of the articles in this special issue. In this introductory article, we will supply a brief background and introduction to the main topics in agent communication

agent technology
AI programs
agent communication language
inter-agent communication
agent societies
KQML
semantics
conversations
distributed software engineering
machine learning
negotiation
teamwork
social sciences


Rats, robots, and rescue

Abstract: In early May, media inquiries started arriving at my office at the Center for Robot-Assisted Search and Rescue (www.crasar.org). Because I'm CRASAR's director, I thought the press was calling to follow up on the recent humanitarian award given to the center's founder, John Blitch, for successfully using small, backpackable robots at the World Trade Center disaster. Instead, I found they were asking me to comment on the "roborats" study in the 2 May 2002 Nature. In this study, rats with medial force brain implants underwent operant conditioning to force them into a form of guided behavior, one aspect of which was thought useful for search and rescue. The article's closing comment suggested that a guided rat could serve as both a mobile robot and a biological sensor. Although a roboticist by training, I'm committed to any technology that will help save lives while reducing the risk to rescuers. But rats?

mobile robot
biological sensor
guided rat
robot-assisted search and rescue