ppxscal/embedding_network huggingface dataset:
Using the web to maintain the benefits of small class instruction in large classes
Authors: Gabriele Meiselwitz
Venue: Journal of Computing Sciences in Colleges (2002)

The World-Wide-Web is used in many classrooms today and distance education via the Internet has replaced a number of traditional, lecture-style courses. Class sizes of 100 or more students in introductory computer science courses are not uncommon. To manage the high number of students, large sections are often taught in lecture halls or as online versions using the Internet and the World-Wide Web. In an attempt to combine the positive aspects of in-class instruction with those of online education and to enhance the learning experience for students in large classes we have created a hybrid course model. In our new course structure in-class time is reduced, but not completely eliminated and at the same time some in-class instruction is replaced by Web-based instruction elements. We have applied this model to one of our entry-level, general education computer science courses successfully. This paper describes the course model and reports on our experiences.
Representation of digital image by fuzzy neural network
Authors: Puyin Liu
Venue: Fuzzy Sets and Systems (2002)

A multilayer feedforward fuzzy neural network(FNN), by which the predetermined fuzzy system can be realized is constructed to express a given two-dimensional (2-D) digital image. It is shown that such a network is universal approximator. The FNN approach provides us with the representation model of the 2-D discrete image. In noise environment some given fuzzy numbers are employed to describe gray levels of a digital image and the deviation of corrupted image to its noise-free one. A class of fuzzy rules for removing impulse noise in degraded image are presented. The corresponding FNN may work as a filter, which improves the performances of median and rank-conditioned rank selection filters. Especially, such a filter may to a greatest extent maintain the fine structure of the image. Under the minimum mean absolute error criterion the membership functions of fuzzy numbers are adaptively adjusted, and an optimal FNN for image representation is derived in noise environment. Simultaneously some real image examples are systemically analyzed to show that the FNN may result in higher quality global restoration.
A probabilistic approach to information hiding
Authors: Annabelle McIver, Carroll Morgan
Venue: Programming methodology (2003)

Security in a computer system must at some level be regarded as the control of information flow. Here we approach the issue 'from first principles', linking information flow in the sense of Shannon to a sequential programming model enriched with probabilities. From that we extract criteria for secure encapsulation of data, and we discuss the interaction of our criteria with refinement.
Efficient micro-mobility using intra-domain multicast-based mechanisms (M M)
Authors: Ahmed Helmy, Muhammad Jaseemuddin, Ganesha Bhaskara
Venue: ACM SIGCOMM Computer Communication Review (2002)

One very important metric in evaluation of IP mobility protocols is handover performance. Handover occurs when a mobile node changes its network point-of-attachment. If not performed efficiently, handover delays, jitters and packet loss directly impact applications and services. With the Internet growth and heterogeneity, it becomes crucial to design efficient handover protocols that are scalable, robust and incrementally deployable. Mobile IP (MIP) has been shown to exhibit poor handover performance during micro-mobility. We propose a new architecture for providing efficient and smooth handover, while being able to coexist and inter-operate with other technologies. Specifically, we propose an intra-domain multicast-based mobility architecture, where a visiting mobile is assigned a multicast address to use while moving within a domain. Efficient handover is achieved using standard multicast join/prune mechanisms.Two approaches are proposed and contrasted. The first introduces the concept of proxy-based mobility, while the other uses algorithmic mapping to obtain the multicast address of visiting mobiles. We show that the algorithmic mapping approach has several advantages over the proxy approach, and provide mechanisms to support it.Simulations used to evaluate our scheme and compare it to other micro-mobility schemes - CIP and HAWAII. The proactive handover results show that both M&M and CIP show low handoff delay and packet reordering depth as compared to HAWAII. The reason for M&M's comparable performance with CIP is that both use bi-cast in proactive handover. M&M, however, handles multiple border routers in a domain, where CIP fails. Also using a proactive path setup mechanism, we show that M&M clearly outperforms CIP in case of reactive handover.
The Nonpreemptive Priority Map/G/1 Queue
Authors: José Manuel Campa, Mauro F. Guillén, Gila E. Fruchter, Tetsuya Takine
Venue: Operations Research (1999)

This paper considers the nonpreemptive priority queue with MAP (Markovian Arrival Process) arrivals. Since MAP is weakly dense in the class of stationary point processes, it is a fairly general arrival process. Service times of customers of each priority class are independent and identically distributed according to a general distribution function that may differ among priority classes. Using both the generating function technique and the matrix analytic method, we derive various formulas for the marginal queue length distribution of each class. Further, we provide the delay cycle analysis of the waiting time distribution of each class and characterize its Laplace-Stieltjes transform.
Note: on Semi-Active Timetabling in Resource-Constrained Project Scheduling
Authors: Arno Sprecher, Andreas Drexl
Venue: Management Science (1999)

The purpose of this note is to demonstrate that the branch-and-bound algorithm presented in Demeulemeester and Herroelen (1992) does not reduce the enumeration to semi-active schedules.
A Generalization of the Perfect Graph Theorem Under the Disjunctive Index
Authors: Néstor E. Aguilera, Mariana S. Escalante, Garaeila L. Nasini
Venue: Mathematics of Operations Research (2002)

In this paper, we relate antiblocker duality between polyhedra, graph theory, and the disjunctive procedure. In particular, we analyze the behavior of the disjunctive procedure over the clique relaxation, ( G), of the stable set polytope in a graph R G, and the one associated to its complementary graph, R( G). We obtain a generalization of the Perfect Graph Theorem, proving that the disjunctive indices of R( G) and R( G) always coincide.
A proposal for a new hardware cache monitoring architecture
Authors: Martin Schulz, Jie Tao, Jürgen Jeitner, Wolfgang Karl
Venue: Proceedings of the 2002 workshop on Memory system performance (2002)

The analysis of the memory access behavior of applications, an essential step for a successful cache optimization, is a complex task. It needs to be supported with appropriate tools and monitoring facilities. Currently, however, users can only rely on either simulation based approaches, which deliver a large degree of detail but are restricted in their applicability, or on hardware counters embedded into processors, which allow to keep track of very few, mostly global events and hence only provide limited data.In this work a proposal for novel hardware monitoring facility is presented which exhibits both the details of traditional simulations and the low--overhead of hardware counters. Like the latter approach, it is also targeted towards an implementation within the processor for a direct and non--intrusive access to caches and memory busses. Unlike traditional counters, however, it delivers a detailed picture of the complete memory access behavior of applications. This is achieved by generating so--called memory access histograms, which show access frequencies in relation to the applications address space. Such spatial memory access information can then be used for efficient program optimization by focusing on the code and data segments which were found to exhibit a poor cache behavior.
Computing Temporal Aggregates
Authors: Nick Kline, Richard Thomas Snodgrass
Venue: Proceedings of the Eleventh International Conference on Data Engineering (1995)

Aggregate computation, such as selecting the minimum attribute value of a relation, is expensive, especially in a temporal database. We describe the basic techniques behind computing aggregates in conventional databases and show that these techniques are not efficient when applied to temporal databases. We examine the problem of computing constant intervals (intervals of time for which the aggregate value is constant) used for temporal grouping. We introduce two new algorithms for computing temporal aggregates: the aggregation tree and the k-ordered aggregation tree. An empirical comparison demonstrates that the choice of algorithm depends in part on the amount of memory available, the number of tuples in the underlying relation, and the degree to which the tuples are ordered. This study shows that the simplest strategy is to first sort the underlying relation, then apply the k-ordered aggregation tree algorithm with k=1.
Fault model-driven test derivation from finite state models: annotated bibliography
Authors: Alexandre Petrenko
Venue: Modeling and verification of parallel processes (2001)

The annotated bibliography highlights work in the area of algorithmic test generation from formal specifications with guaranteed fault coverage, i.e., fault model-driven test derivation. A fault model is understood as a triple, comprising a finite state specification, conformance relation and fault domain that is the set of possible implementations. The fault model can be specialized to Input/Output FSM, Labeled Transition System, or Input/Output Automaton and to a number of conformance relations such as FSM equivalence, reduction or quasi-equivalence, trace inclusion or trace equivalence and others. The fault domain usually reflects test assumptions, as an example, it can be the universe of all possible I/O FSMs with a given number of states, a classical fault domain in FSM-based testing. A test suite is complete with respect to a given fault model when each implementation from the fault domain passes it if and only if the postulated conformance relation holds between the implementation and its specification. A complete test suite is said to provide fault coverage guarantee for a given fault model.
Dynamic Economic Lot Size Models with Period-Pair-Dependent Backorder and Inventory Costs
Authors: Vernon Ning Hsu, Timothy J. Lowe
Venue: Operations Research (2001)

Inventory and backorder cost functions in the classical Wagner-Whitin economic lot size (ELS) models are typically period-pair-independent ( pp-independent) in the sense that inventoried units carried (or backorders in existence) in a given period are treated the same regardless of the periods in which they are produced (placed) or the periods in which they are used (filled). We consider versions of the problem where inventory and backorder costs arepp-dependent, as well as versions where backorder costs, but not inventory costs, are pp-dependent. Recognizing that the problems considered are NP-hard, we provide cases where the cost structure allows polynomial solvability via dynamic programming.
A Stochastic Convergence Model for Portfolio Selection
Authors: Amy V. Puelz
Venue: Operations Research (2002)

Portfolio selection techniques must provide decision makers with a dynamic model framework that incorporates realistic assumptions regarding financial markets, risk preferences, and required portfolio characteristics. Unfortunately, multistage stochastic programming (SP) models for portfolio selection very quickly become intractable as assumptions are relaxed and uncertainty is introduced. In this paper, I present an alternative model framework for portfolio selection, stochastic convergence (SC), that systematically incorporates uncertainty under a realistic assumption set. The optimal portfolio is derived through an iterative procedure, where portfolio plans are evaluated under many possible future scenarios then revised until the model converges to the optimal plan. This approach allows for scenario analysis over all stochastic components, requires no limitation on the structural form of the objective or constraints, and permits evaluation over any length planning horizon while maintaining model tractability by aggregating the scenario tree at each stage in the solution process. Through focused aggregation schemes, the SC approach allows for the implementation of a lower partial variance riskmetric, which is preferred in investment selection. In simulated tests, the SC model, with scenario aggregation, generated portfolios exhibiting performance similar to those generated using the SP model form with no aggregation. Empirical tests using historical fund returns show that a multiperiod SC decision strategy outperforms various benchmarkstrate gies over a long-term test horizon under both asset-liability matching and return maximization frameworks.
On Equitable Resource Allocation Problems: a Lexicographic Minimax Approach
Authors: Tamon Stephen, Levent Tuncel, Hanan Luss
Venue: Operations Research (1999)

In this expository paper, we review a variety of resource allocation problems in which it is desirable to allocate limited resources equitably among competing activities. Applications for such problems are found in diverse areas, including distribution planning, production planning and scheduling, and emergency services location. Each activity is associated with a performance function, representing, for example, the weighted shortfall of the selected activity level from a specified target. A resource allocation solution is called equitable if no performance function value can be improved without either violating a constraint or degrading an already equal or worse-off (i.e., larger) performance function value that is associated with a different activity. A lexicographic minimax solution determines this equitable solution; that is, it determines the lexicographically smallest vector whose elements, the performance function values, are sorted in nonincreasing order. The problems reviewed include large-scale allocation problems with multiple knapsack resource constraints, multiperiod allocation problems for storable resources, and problems with substitutable resources. The solution of large-scale problems necessitates the design of efficient algorithms that take advantage of special mathematical structures. Indeed, efficient algorithms for many models will be described. We expect that this paper will help practitioners to formulate and solve diverse resource allocation problems, and motivate researchers to explore new models and algorithmic approaches.
The dynamic response of a two-dimensional airfoil with bilinear structural nonlinearity
Authors: L. Liu, Y. S. Wong, B. H. K. Lee
Venue: Scientific computing and applications (2001)

In this study, we investigate the dynamic response of a two-dimensional airfoil oscillating in an incompressible flow with a structural nonlinearity represented by a bilinear spring. The point transformation method is applied to this piece-wise linear system. An algorithm is derived to capture the traveling times and the crossing points, based on which we could determine the motion type. Following this procedure, period-n motions and chaos can be detected. Furthermore, once the system parameters are fixed, the frequencies and the amplitudes of limit cycle oscillations can be determined directly from the frequency-amplitude prediction equations without solving the time history for the motion. Theoretical results are given for specific system parameters, and they are verified with the numerical results obtained using the fourth-order Runge-Kutta time integration scheme.
Research Commentary: The Organizing Logic for an Enterprise's IT Activities in the Digital Era--A Prognosis of Practice and a Call for Research
Authors: V. Sambamurthy, Robert W. Zmud
Venue: Information Systems Research (2000)

Prior research has generated considerable knowledge about the design of effective IT organizational architectures. Today, however, increasing signs have accumulated that this wisdom might be inadequate in shaping appropriate insights for contemporary practice. This essay seeks to direct research attention toward the following question:How should firms organize their IT activities in order to manage the imperatives of the business and technological environments in the digital economy? We articulate the platform logic as a conceptual framework for both viewing the organizing of IT management activities as well as for framing important questions for future research. In articulating this logic, we aim to shift thinking away from the traditional focus on governance structures (i.e., choice of centralized, decentralized, or federal forms) and sourcing structures (i.e., insourcing, outsourcing) and toward more complex structures that are reflective of contemporary practice. These structures are designed around important IT capabilities and network architectures.
Exact tests in simple growth curve models and one-way ANOVA with equicorrelation error structure
Authors: Shu-Hui Lin, Jack C. Lee
Venue: Journal of Multivariate Analysis (2003)

We consider exact tests with several equicorrelation error structures and combination of equicorrelation covariance structures in simple growth curve model having single or multiple treatments and in one-way ANOVA model. Exact inferences using generalized p-values are obtained. Tests for equal treatment effects under equal equicorrelation error term and for unequal equicorrelation error terms are also developed. Two examples are given to illustrate the importance of our results. According to our findings, we would be better off dropping the assumption of equal variance when the heteroscedasticity is serious. Therefore, tests based on generalized p-values without the assumption of equal variance are much more powerful than tests with this assumption.
Implementing Sustainability in Service Operations at Scandic Hotels
Authors: Ann Goodman
Venue: Interfaces (2000)

The case of Scandic Hotels shows, first, that sustainable strategies and practices can be just as useful in service operations as in manufacturing operations; and second, that such strategies and practices can support a corporate turnaround effort. Scandic Hotels, Nordic Europe's biggest hotel chain, was on the verge of collapse in the early 1990s. A new CEO, Roland Nilsson, turned the company around by introducing two business principles, decentralized management and sustainable development. The company's new value system, embodied in the concept of sustainability, linked customers and employees, who were calling for more environmental responsibility. Through employee-training programs, environmental information systems, and innovative collaborations with suppliers, Scandic was revived within a few years as a profitable corporation well on the road to sustainability.
A unified approach to Newton-Cotes quadrature formulae
Authors: Moawwad El-Mikkawy
Venue: Applied Mathematics and Computation (2003)

In this paper the author introduces a new approach to obtain the Cotes numbers for both the open and closed Newton-Cotes quadrature formulae. He also introduces a new definition for the degree of exactness for a quadrature formula. Some numerical results are presented.
A Quasi-Minimal Residual Method for Simultaneous Primal-Dual Solutions and Superconvergent Functional Estimates
Authors: James Lu, David L. Darmofal
Venue: SIAM Journal on Scientific Computing (2002)

The adjoint solution has found many uses in computational simulations where the quantities of interest are the functionals of the solution, including design optimization, error estimation, and control. In those applications where both the solution and the adjoint are desired, the conventional approach is to apply iterative methods to solve the primal and dual problems separately. However, we show that there is an advantage associated with iterating the primal and dual problem simultaneously since this enables the construction of iterative methods where both the primal and the dual iterates may be chosen so that they provide functional estimates that are "superconvergent" in that the error converges at twice the order of the optimal global solution error norm. In particular, we show that the structure of the Lanczos process allows for this superconvergence property and propose a modified QMR method which uses the same Lanczos process to simultaneously solve the primal and dual problems. Thus both the primal and the dual systems are solved at essentially the same computational cost as the conventional QMR method applied to the primal problem alone. Numerical experiments show that our proposed method does indeed exhibit superconvergence behavior.
The Stabilizing Effect of Inventory in Supply Chains
Authors: Manuel P. Baganha, Morris A. Cohen
Venue: Operations Research (1998)

This paper presents a hierarchical model framework for the analysis of the stabilizing effect of inventories in multiechelon manufacturing/distribution supply chains. This framework is used to compare the variance of demand to the variance of replenishment orders at different echelons of the system (e.g., retailer, wholesaler). Empirical data and experience with management games suggest that, in most industries, inventory management policies can have a destabilizing effect by increasing the volatility of demand as it passes up through the chain (the "bullwhip" effect). Our model helps to explain these observations and indicates mechanisms that can promote stabilization. The analysis results also define sufficient conditions for the existence of stabilization and relate these conditions to the optimality of myopic control policies.
Lagrange interpolation on conics and cubics
Authors: J. M. Carnicer, M. García-Esnaola
Venue: Computer Aided Geometric Design (2002)

A bivariate polynomial interpolation problem for points lying on an algebraic curve is introduced. The geometric characterization introduced by Chung and Yao, which provides simple Lagrange formulae, is here analyzed for interpolation points lying on a line, a conic or a cubic.
Technology-push or user-pull? The slow death of the transfer-of-technology approach to intelligent support systems development
Authors: Teresa Lynch, Shirley Gregor
Venue: Socio-technical and human cognition elements of information systems (2003)

This chapter describes a study of the adoption of intelligent support systems in agriculture. The aim was to investigate the apparent low uptake of these systems and the approaches used in development-whether 'user-pull' or 'technology-push.' Data was collected for 66 systems, mainly through telephone interviews. An interpretative approach to research was adopted. The nature of user influence in the development process and the nature of the outcomes for the systems were found to be complex and multidimensional constructs. A pattern emerged showing the technology-push approach was associated with low levels of user influence in the development process and comparatively low levels of system impact. This relationship was more evident in systems developed by government organizations.