ppxscal/embedding_network huggingface dataset:
Root cases of large sets of t-designs
Authors: G. B. Khosrovshahi, B. Tayfeh-Rezaie
Venue: Discrete Mathematics (2003)

A large set of t-(v, k, λ) designs of size N, denoted by LS[N](t, k, v), is a partition of all k-subsets of a v-set into N disjoint t-(v, k, λ) designs, where N = (v-t/k-t)/λ. A set of trivial necessary conditions for the existence of an LS[N](t, k, v) is N|v-t/k-t for i = 0,.....,t. In this paper we extend some of the recursive methods for constructing large sets of t-designs of prime sizes. By utilizing these methods we show that for the construction of all possible large sets with the given N, t, and k, it suffices to construct a finite number of large sets which we call root cases. As a result, we show that the trivial necessary conditions for the existence of LS[3](2, k, v) are sufficient for k ≤ 80.
Evidence-based careflow management systems: the case of post-stroke rehabilitation
Authors: S. Panzarasa, S. Maddè, S. Quaglini, C. Pistarini, M. Stefanelli
Venue: Journal of Biomedical Informatics (2002)

The activities of a care providers' team need to be coordinated within a process properly designed on the basis of available best practice medical knowledge. It requires a rethinking of the management of care processes within health care organizations. The current workflow technology seems to offer the most convenient solution to build such cooperative systems. However, some of its present weaknesses still require an intense research effort to find solutions allowing its exploitation in real medical practice. This paper presents an approach to design and build evidence-based careflow management systems, which can be viewed as components of a knowledge management infrastructure each health care organization should be provided with to increase its performance in delivering high quality care by efficiently exploiting the available knowledge resources. The post-stroke rehabilitation process has been taken as a challenging care problem to assess our methodology for designing and developing careflow management systems. Then a system was co-developed with a team of rehabilitation professionals who will be committed to use it in their daily work. The system's main goal is to deliver a full array of rehabilitation services provided by an interdisciplinary team. They are related to identify which patients are most likely to benefit from rehabilitation, manage a rehabilitation treatment plan, and monitor progress both during rehabilitation and after return to a community residence. A model of the rehabilitation process was derived from an international guideline and adapted to the local organization of work. It involves different organizational units, such as wards, rehabilitation units, clinical laboratories, and imaging services. Several organizational agents work within them and play one or more roles. Each role is defined by the goals' set that she/he must fulfill. Special effort has been given to the design and development of a knowledge-based system for managing exceptions, which may occur in daily medical work as any deviation from the normal flow of activities. It allows either avoiding or recovering automatically from expected exceptions. When they are not expected, organizational agents, with enough power to do that, are allowed to modify the scheduled flow of activities for an individual patient under the only constraint of justifying their decision. After an intensive testing in a research laboratory, the system is now in the process of being transferred in a real working setting with the full support of its future users.
Vector field visualization using Markov Random Field texture synthesis
Authors: Francesca Taponecco, Marc Alexa
Venue: Proceedings of the symposium on Data visualisation 2003 (2003)

Vector field visualization aims at generating images in order to convey the information existing in the data. We use Markov Random Field (MRF) texture synthesis methods to generate the visualization from a set of sample textures. MRF texture synthesis methods allow generating images that are locally similar to a given example image. We extend this idea for vector field visualization by identifying each vector value with a representative example image, e.g. a strongly directed texture that is rotated according to a 2D vector. The visualization is synthesized pixel by pixel, where each pixel is chosen from the sample texture according to the vector values of the local pixel. The visualization locally communicates the vector information as each pixel is chosen from a sample that is representative of the vector. Furthermore it is smooth, as MRF texture synthesis searches for best fitting neighborhoods. This leads to dense and smooth visualizations with the additional freedom to use arbitrary representation textures for any vector value.
Ordering Fault-Prone Software Modules
Authors: Taghi M. Khoshgoftaar, Edward B. Allen
Venue: Software Quality Control (2003)

Software developers apply various techniques early in development to improve software reliability, such as extra reviews, additional testing, and strategic assignment of personnel. Due to limited resources and time, it is often not practical to enhance the reliability of all modules. Our goal is to target reliability enhancement activities to those modules that would otherwise have problems later. Prior research has shown that a software quality model based on software product and process metrics can predict which modules are likely to have faults.A module-order model is a quantitative software quality model that is used to predict the rank-order of modules according to a quality factor, such as the number of faults. The contribution of this paper is definition of module-order models and a method for their evaluation and use. Two empirical case studies of full-scale industrial software systems provide empirical evidence of the usefulness of module-order models for targeting reliability enhancement.
Finite element approximation of H-surfaces
Authors: Yuki Matsuzawa Takashi Suzuki, Takuya Tsuchiya
Venue: Mathematics of Computation (2003)

In this paper a piecewise linear finite element approximation of H-surfaces, or surfaces with constant mean curvature, spanned by a given Jordan curve in R3 is considered. It is proved that the finite element H- surfaces converge to the exact H-surfaces under the condition that the Jordan curve is rectifiable. Several numerical examples are given.
Inventory Competition Under Dynamic Consumer Choice
Authors: Siddharth Mahajan, Garrett Van Ryzin
Venue: Operations Research (2001)

We analyze a model of inventory competition among n firms that provide competing, substitutable goods. Each firm chooses initial inventory levels for their good in a single period (newsboy-like) inventory model. Customers choose dynamically based on current availability, so the inventory levels at one firm affect the demand of all competingfirms. This creates a strategic interaction amongthe firms' inventory decisions. Our work extends earlier work on variations of this problem by Karjalainen (1992), Lippman and McCardle (1997) and Parlar (1988). Specifically, we model demand in a more realistic way as a stochastic sequence of heterogeneous consumers who choose dynamically from amongthe available goods (or choose not to purchase) based on a utility maximization criterion. We also use a sample path analysis, so minimal assumptions are imposed on this demand process. We characterize the Nash equilibrium of the resulting stocking game and prove it is unique in the symmetric case. We show there is a bias toward overstocking caused by competition; specifically, reducing the quantity stocked at any equilibrium of the game increases total system profits, and at any joint-optimal set of stocking levels, each firm has an individual incentive to increase its own stock. For the symmetric case, we show that as the number of competing firms increases, the overstockingbecomes so severe that total system (and individual firm) profits approach zero. Finally, we propose a stochastic gradient algorithm for computing equilibria and provide several numerical examples.
Leadtime-Inventory Trade-Offs in Assemble-To-Order Systems
Authors: Paul Glasserman, Yashan Wang
Venue: Operations Research (1998)

This paper studies the trade-off between inventory levels and the delivery leadtime offered to customers in achieving a target level of service. It addresses the question of how much a delivery leadtime can be reduced, per unit increase in inventory, at a fixed fill rate. We show that for a class of assemble-to-order models with stochastic demands and production intervals there is a simple linear trade-off between inventory and delivery leadtime, in a limiting sense, at high fill rates. The limiting slope is easy to calculate and can be interpreted as the approximate marginal rate for trading off inventory against leadtime at a constant level of service. We also investigate how various model features affect the trade-off-in particular, the impact of orders for multiple units of a single item and of orders for multiple units of different items.
A Primal Method for the Solution of the Groundwater Quality Management Problem
Authors: Tullio Tucciarelli, George P. Karatzas, George F. Pinder
Venue: Operations Research (1998)

A new algorithm for the solution of the groundwater quality management problem is presented. The method assumes that most of the computational effort in such problems involves evaluation of the concentrations and their derivatives with respect to the pumping rates at the control points. The methodology proposed herein is a combination of the cutting plane method and the primal method. In this approach each line search moves from a feasible point towards the solution of a subproblem with linear constraints and the same objective function as the original problem. Sensitivity analysis is used to compute the derivative of a single concentration with respect to all the pumping rates by solving only one linear system at each time step. The method has been tested with analytical convex problems and a model example. A comparison of the algorithm's performance was conducted using MINOS 5.1. For the case of a linear cost function the method shows a computational growth rate almost linearly proportional to the number of decision variables.
Research Commentary: Introducing a Third Dimension in Information Systems Design--The Case for Incentive Alignment
Authors: Sulin Ba, Jan Stallaert, Andrew B. Whinston
Venue: Information Systems Research (2001)

Prior research has generated considerable knowledge on information systems design from software engineering and user-acceptance perspectives. As organizational processes are increasingly embedded within information systems, one of the key considerations of many business processes--organizational incentives--should become an important dimension of any information systems design and evaluation, which we categorize as the third dimension: incentive alignment. Incentive issues have become important in many IS areas, including distributed decision support systems (DSS), knowledge management, and e-business supply chain coordination. In this paper we outline why incentives are important in each of these areas and specify requirements for designing incentive-aligned information systems. We identify and define important unresolved problems along the incentive-alignment dimension of information systems and present a research agenda to address them.
Microarchitectural support for precomputation microthreads
Authors: Robert S. Chappell, Francis Tseng, Adi Yoaz, Yale N. Patt
Venue: Proceedings of the 35th annual ACM/IEEE international symposium on Microarchitecture (2002)

Research has shown that precomputation microthreads can be useful for improving branch prediction and prefetching. However, it is not obvious how to provide the necessary microarchitectural support, and few details have been given in the literature. By judiciously constraining microthreads, we can easily adapt a superscalar machine to support many simultaneous microthreads. The nature of precomputation microthreads also requires efficient usage of resources. Our proposed implementation addresses this issue by dynamically identifying and aborting useless microthreads.
Staff scheduling at the United States postal service
Authors: Jonathan F. Bard, Canan Binici, Anura H. deSilva
Venue: Computers and Operations Research (2003)

The purpose of this paper is to present a full-scale model of the tour scheduling problem as it arises in the United States Postal Service, and to examine several scenarios aimed at reducing the size of the workforce. The problem is formulated as a pure integer linear program and solved with CPLEX. The baseline model includes both full-time and part-time workers, as well as the principal constraints defined by the union contract. The scenarios include requirements for two days off in a row, variable daily start times, the use of part-time flexible workers, and a parametric analysis of full-time to part-time restrictions. The results indicate that problem instances of realistic size can be solved within 1 h, and that measurable savings can be achieved by departing from current practice.
Internet Mail Transfer and Check System Based on Intelligence Mobile Agents
Authors: Li Cheng, Wang Weinong
Venue: Proceedings of the 2002 Symposium on Applications and the Internet (2002)

The Simple Mail Transfer Protocol (SMTP) based E-mail system is the most popular application in today's Internet world, but there are many dark clouds at the edge of the sunshiny sky. The most well known two threats are the "mail SPAM" and the "mail flooding attack." Mobile agents (MAs) are software agents that can transport themselves from a client computer to various servers for remote execution. Their mobility, autonomy and distributed intelligence are very friendly to today and tomorrow's Internet computation. In this paper, we introduce a prototype of the Internet mail transfer and check system based on intelligence mobile agents. This new system model can improve the current simple mail transfer protocol model to defend the mail SPAM and the mail flooding attack. Compatible with the traditionary SMTP is the most important feature of our new model. Finally, we summarize some difficulties for turning this prototype model into practical software.
Efficient synchronization for nonuniform communication architectures
Authors: Zoran Radović, Erik Hagersten
Venue: Proceedings of the 2002 ACM/IEEE conference on Supercomputing (2002)

Scalable parallel computers are often nonuniform communication architectures (NUCAs), where the access time to other processor's caches vary with their physical location. Still, few attempts of exploring cache-to-cache communication locality have been made. This paper introduces a new kind of synchronization primitives (lock-unlock) that favor neighboring processors when a lock is released. This improves the lock handover time as well as access time to the shared data of the critical region.A critical section guarded by our new RH lock takes less than half the time to execute compared with the same critical section guarded by any other lock on our NUCA hardware. The execution time for Raytrace with 28 processors was improved 2.23--4.68 times, while global traffic was dramatically decreased compared with all the other locks. The average execution time was improved 7--24% while the global traffic was decreased 8-28% for an average over the seven applications studied.
Bridging the digital divide by co-creating a collaborative computer science classroom
Authors: Mary Kirk, Carol Zander
Venue: Journal of Computing Sciences in Colleges (2002)

Although the so-called "digital divide" is a popular topic of discussion among computer scientists and women's studies scholars, these two discourses rarely intersect, either theoretically or practically--creating a disciplinary divide. Women's studies scholars have thoroughly documented the historical barriers to science and computing for women and have outlined successful strategies for retaining women in computer science classrooms. However, few computer science educators are familiar with women's studies scholarship. This paper, which combines the perspectives of a women's studies scholar and a computer scientist, attempts to bridge the disciplinary divide between computer science and women's studies. In Section 1, we explain how the historical legacies of two fundamental themes implicit in the philosophy of science contribute to the exclusive environment in computer science classrooms today: 1) science=male, nature=female, and 2) exclusive epistemologies and pedagogies that privilege "maleness" over "femaleness." In Section 2, we offer a few practical pedagogical strategies for bridging the digital divide in computer science classrooms by co-creating collaborative rather than competitive learning environments. In Section 3, we explain what is required of computer science faculty if we are to halt the exit of talented women from our programs.
The effect of across-location heteroscedasticity on the classification of mixed categorical and continuous data
Authors: Chi-Ying Leung
Venue: Journal of Multivariate Analysis (2003)

Classification of mixed categorical and continuous data is often performed using the location linear discriminant function which assumes across-location homoscedasticity. In this paper, we investigate the hazard arising from a routine application of the classifier under across-location heteroscedasticity. A limiting and a first-order asymptotic performance index are proposed and studied in a general setting. The first index studies the limiting behavior. The second index corrects the bias due to the finite sample size. Both indexes are illustrated under the assumption of unequal spherical covariance matrices across all the locations. This is likely to be the case in most classification problems dealing with mixed categorical and continuous data. Results of a numerical study are reported.
Positive solutions for second-order m-point boundary value problems
Authors: Yanping Guo, Wenrui Shan, Weigao Ge
Venue: Journal of Computational and Applied Mathematics (2003)

By using the Schauder fixed point theorem and analysis method, we establish the existence of solutions for the m-point boundary value problem u"(t) + a(t)f(u) = 0, u(0)= 0, u(1) - Σi=1m-2kiu(ξi) = b, where b, ki > 0 (i = 1,2,...,m - 2),0 < ξ1 < ξ2 < ... < ξm-2 < 1, a(t) is allowed to be singular at t = 0,1. Under some conditions, we show that there exists a positive number b* such that the problem has at least one positive solution for 0 < b < b* and no solution for b > b*.
An elementary Abelian group of large rank is not a CI-group
Authors: M. Muzychuk
Venue: Discrete Mathematics (2003)

In this paper, we prove that the group Zpn is not a CI-group if n ≥ 2p - 1 + (2p-1/p), that is there exist two Cayley digraphs over Zpn which are isomorphic but their connection sets are not conjugate by an automorphism of Zpn.
Levels of dynamics and adaptive behavior in evolutionary neural controllers
Authors: Jesper Blynel, Dario Floreano
Venue: Proceedings of the seventh international conference on simulation of adaptive behavior on From animals to animats (2002)

Two classes of dynamical recurrent neural networks, Continuous Time Recurrent Neural Networks (CTRNNs) (Yamauchi and Beer, 1994) and Plastic Neural Networks (PNNs) (Floreano and Urzelai, 2000) are compared on two behavioral tasks aimed at exploring their capabilities to display reinforcement-learning like behaviors and adaptation to unpredictable environmental changes. The networks report similar performances on both tasks, but PNNs display significantly better performance when sensory-motor re-adaptation is required after the evolutionary process. These results are discussed in the context of behavioral, biological, and computational definitions of learning.
Adaptivity for improving web streaming application performance
Authors: Julie A. McCann
Venue: Adaptive evolutionary information systems (2003)

This chapter introduces adaptivity and Internet applications. Its focus is on streaming media, i.e., in particular, the streaming of audio over the web. It argues that to achieve good quality end-to-end performance (between client and server), adaptive architectures provide a better solution in terms of scaleability and network fairness than that of reservation techniques. However, this is at the cost of reducing the 100% end-to-end performance guarantee. The Kendra adaptive content delivery architecture is discussed as a proof of concept highlighting the parameters that most affected performance. Kendra is then critiqued in terms of alternative solutions showing where future research in this area could lie.
A configurable type hierarchy index for OODB
Authors: Thomas A. Mueck, Martin L. Polaschek
Venue: The VLDB Journal &mdash; The International Journal on Very Large Data Bases (1997)

With respect to the specific requirements of advanced OODB applications, index data structures for type hierarchies in OODBMS have to provide efficient support for multiattribute queries and have to allow index optimization for a particular query profile. We describe the multikey type index and an efficient implementation of this indexing scheme. It meets both requirements: in addition to its multiattribute query capabilities it is designed as a mediator between two standard design alternatives, key-grouping and type-grouping. A prerequisite for the multikey type index is a linearization algorithm which maps type hierarchies to linearly ordered attribute domains in such a way that each subhierarchy is represented by an interval of this domain. The algorithm extends previous results with respect to multiple inheritance. The subsequent evaluation of our proposal focuses on storage space overhead as well as on the number of disk I/O operations needed for query execution. The analytical results for the multikey type index are compared to previously published figures for well-known single-key search structures. The comparison clearly shows the superiority of the multikey type index for a large class of query profiles.
Model Specification of a Noncausal 3-D AR Process Using a Causal 3-D AR Model on the Nonsymmetric Half-Space
Authors: Byoungseon Choi
Venue: Multidimensional Systems and Signal Processing (2003)

There exists a causal 3-D AR process on the nonsymmetric half-space having the same autocorrelations as a noncausal 3-D AR process. A formula is presented to relate the AR coefficients of the noncausal 3-D AR process with those of the causal 3-D AR process on the nonsymmetric half-space. The 3-D Yule-Walker equations are derived for causal 3-D AR models on the nonsymmetric half-space, and a computationally efficient order-recursive algorithm is proposed to solve the 3-D Yule-Walker equations. We can easily specify a noncausal 3-D AR process from its autocorrelations using the autocorrelation equivalence relation, the formula of the AR coefficients and the order-recursive algorithm.
A Grounded Model of Organizational Schema Change During Empowerment
Authors: Giuseppe Labianca, Barbara Gray, Daniel J. Brass
Venue: Organization Science (2000)

We analyzed employee resistance to an organizational change project in which employees were empowered to participate in the design of a new organizational structure. What emerged from our analysis was the importance of cognitive barriers to empowerment. Employees' resistance appeared to be motivated less by intentional self-interest than by the constraints of wellestablished, ingrained schemas. Resistance was also fueled by skepticism among the employees about management's commitment to the new decision-making schema, especially because employees judged managerial actions to be inconsistent with their new espoused framework. A grounded model of schema change is developed for changes in organizational decision-making schemas during empowerment efforts. Theoretical implications and suggestions for improving organizational change efforts are proposed.