ppxscal/embedding_network huggingface dataset:
Hexagonal systolic arrays for matrix multiplication
Authors: M. P. Bekakos, I. Ž. Milovanović E. I. Milovanović T. I. Tokić M. K. Stojčev
Venue: Highly parallel computaions: algorithms and applications (2001)

We consider the problem of matrix multiplication on hexagonal systolic arrays (SA). We begin with the description of the procedure for systolic array designing which is based on data dependency and space-time mapping of the nested loop algorithms. Then we introduce some performance measures which are used throughout the chapter for comparison of various SAs. We proceed with modification of the standard design procedure which enables synthesis of systolic arrays with the optimal number of processing elements (PE) for a given problem size and minimal execution time for a given number of PEs. Then we analyse and compare different hexagonal arrays. Further, we show how execution time of matrix multiplication algorithm can be reduced if the number of PEs is increased with respect to the optimal one. Finally, we address the problem of fault-tolerant matrix multiplication on hexagonal arrays.
Local action systems and DPO graph transformation
Authors: Dirk Janssens
Venue: Formal and natural computing (2002)

A comparison between DPO graph rewriting and Local Action Systems is presented. It is shown that, as far as the sequential behaviour is concerned, each Local Action Systems can be simulated by a set of Double Pushout productions and vice versa. The encoding used is fairly straightforward, and it is easy to give conditions under which it preserves the finiteness of the sets of productions involved. As far as the sequential behaviour is concerned, it is shown that the situation is more complicated, and that the constructions presented are not satisfactory in the sense that atomic steps which are parallel independent in one system do not give rise to parallel independent steps in the simulating system.
An Empirical Study of Software Productivity
Authors: Sandro Morasca, Giuliano Russo
Venue: Proceedings of the 25th International Computer Software and Applications Conference on Invigorating Software Development (2001)

We studied productivity in a real-life environment in the Italian Public Administration by applying the Goal/Question/Metrics paradigm to define a productivity-related measurement goal and derive measures that were deemed relevant to reach the stated goal. Productivity was studied from both a functional and a product size perspectives. Our study has highlighted a few factors that are related to either aspect of productivity. The results may provide software managers with support for evaluating and improving software processes, so they can make decisions based on more quantitative information.
Why Analyst Overconfidence About the Functional Form of Demand Models Can Lead to Overpricing
Authors: Alan L. Montgomery, Eric T. Bradlow
Venue: Marketing Science (1999)

Generally, profit predictions are made conditional upon a particular functional form. The typical caveat offered is that this is not the "true" demand model, but is instead some reasonable approximation. We show how the notion of an approximation can be explicitly represented using a random coefficient model. Our model nests the usual situation of complete model certainty as a special case. We go on to show how ignoring the uncertainty in functional form induced by approximation will lead to erroneous pricing decisions that may frequently lead to overpricing. For example, an inelastic, double-log demand model implies infinite optimal prices. This is clearly a nonsensical, analyst recommendation. We propose a more general form of the double-log model that allows for high confidence in the observed price range, but incorporates increased uncertainty about the adequacy of the double-log approximation as prices move beyond the observed range. The optimal pricing solutions for this new model are lower than those for the usual case with complete certainty. In fact, we find well-defined optimal pricing solutions even for in elastic double-log demand models. This is a finding of great practical importance, given that aggregate demand models tend to be inelastic for grocery categories, and that log demand models are frequently used (Hoch et al. 1995). We argue that the lackof recognizing uncertainty in the modeling process may par- tially account for why there is a seeming disparity between observed retail prices and the optimal prices implied by maximizing total category profits using estimated demand models (Little and Shapiro 1980). The problems of making optimal pricing decisions using double-log demand models calibrated with store-level scanner data have been recognized. Previous solutions are to constrain the results to achieve reasonable solutions (Reibstein and Gatignon 1984, Montgomery 1997) or to avoid these models altogether in favor of household choice models aggregated to the store-level (Vilcassim and Chintagunta 1995). Our assessment of the problem is that it is not necessarily an issue of model specification, but one of inference. In other words, double-log models fit well, but optimization leads to out-of-range predictions. Our suggestion is that inferences from an estimated demand model need to be approached with some caution. Specifically, uncertainty about predictions will always exist. If this uncertainty is incorporated into models such as the double-log form, then much better inferences can be made. It is our hope that this research will encourage others to think not only about model specification and estimation, but also inference.
Orthogonal rational functions and quadrature on an interval
Authors: J. Van Deun, A. Bultheel
Venue: Journal of Computational and Applied Mathematics (2003)

Rational functions with real poles and poles in the complex lower half-plane, orthogonal on the real line, are well known. Quadrature formulas similar to the Gauss formulas for orthogonal polynomials have been studied. We generalize to the case of arbitrary complex poles and study orthogonality on a finite interval. The zeros of the orthogonal rational functions are shown to satisfy a quadratic eigenvalue problem. In the case of real poles, these zeros are used as nodes in the quadrature formulas.
The Impact of Joint Venture Status on the Longevity of Japanese Stakes in U.S. Manufacturing Affiliates
Authors: Jean-Francois Hennart, Dong-Jae Kim, Ming Zeng
Venue: Organization Science (1998)

A number of well-known studies report that between one-third and two-thirds of international joint ventures eventually break up. While many generalizations, explanations, and prescriptions have been based on these statistics, their meaning is unclear. First, all foreign affiliates are subject to normal business risk, and to the risk that they will be divested by parents for strategic or financial reasons. Are these risks higher for joint ventures than for wholly-owned subsidiaries? Second, joint ventures may be shorter lived not because of their joint venture status, but because affiliates which are joint ventured have other characteristics that make them more likely to exit. To know whether joint ventures are shorter lived, one must control for the other factors that affect the longevity of affiliates, whether wholly owned or joint ventured. Third, many joint ventures contracts contain clauses that allow partners to sell their stakes to one another at specific intervals. Because they make exit easier, joint ventures should have shorter lives, but these shorter lives should only be due to sell-offs, not to liquidations. It is therefore important to see whether the supposedly higher termination rate of joint ventures stakes is due to a higher rate of selloffs or to a higher rate of liquidations. In this paper we (1) compare the longevity of stakes in joint ventures versus those in wholly-owned subsidiaries (2) while controlling for other factors that affect the longevity of such stakes and (3) while distinguishing between two types of exit, those through sale and those through liquidation. While past authors have addressed these three issues in piecemeal fashion, we believe we are the first to address them simultaneously. We analyze the factors that affect the longevity of 355 Japanese stakes in U.S. manufacturing affiliates. Controlling for all the factors that affect exit rates, we find that Japanese parents are more likely to terminate their stakes in U.S. joint ventures than in wholly-owned subsidiaries. This higher termination rate of joint venture stakes is explained by a higher probability of selling them, but not of liquidating them. Most of the other factors that have been found significant in explaining gross divestment of foreign affiliates do in fact only affect exits through sales, but not exits through liquidations. Hence it is true that joint ventures have shorter lives, but dangerous to interpret this finding as necessarily meaning that they are more likely to "fail".
Dyadic Communication Relationships in Organizations: An Attribution/Expectancy Approach
Authors: Bruce Barry, J. Michael Crant
Venue: Organization Science (2000)

Research in organizational communication has examined the structure and content of interaction, but has paid little attention to research traditions outside the organizational sciences that explore the social-psychological interconnections between relationship development and interaction. In this paper we draw upon and extend those traditions to develop a model of how communication relationships develop within organizational dyads. The proposed model examines organization-based communication relationships through a synthesis of theoretical perspectives on communication richness, relational communication, interpersonal attribution, and social expectancy. We also call upon precepts of structuration theory to embed these microlevel processes in an organizational context.The relational outcome in the model is "interactional richness," a dyad-level construct that assesses the extent to which communication within the dyad is high in shared meaning. Model antecedents are aspects of interaction through which communicators reciprocally define their relationships, including relational message properties, message patterns that emerge over time, and relational perceptions. We propose that these communication properties and behaviors give rise to relationship attributions. We then incorporate processes of expectancy confirmation and violation to explain how specific communication encounters lead individuals to reformulate attributions regarding the status of a given relationship. Research propositions articulate how attribution/expectancy processes mediate between relational communication behavior and relationship development outcomes. We also develop propositions addressing how relational communication behavior is influenced by macrolevel factors, including hierarchy, structure, and culture.In a concluding section we discuss the model's potential contribution to research and practice, address its limitations, and offer recommendations for future research aimed at testing its embedded hypotheses.
The challenges of designing lab exercises for a curriculum in computer security
Authors: Rahul Tikekar, Thomas Bacon
Venue: Journal of Computing Sciences in Colleges (2003)

Increasing awareness of the vulnerabilities of computer systems has led to the introduction of several programs in computer security. Most of these programs are meant to attract graduate students. Southern Oregon University has recently started a new undergraduate track in computer security and information assurance. In this paper we describe the development of lab exercises geared toward such a curriculum. The process begins with the curriculum itself and the lab - designing one that mirrors an actual enterprise and allows machines to be "attacked" while protecting the campus and external networks. The next step is designing assignments that model real-world situations like finding vulnerabilities in a system and using them to gain access to the system. The final step is designing larger exercises or projects that can be undertaken at the capstone level or at the graduate level. The paper describes ongoing efforts as well as future plans for such exercises.
RSA Speedup with Chinese Remainder Theorem Immune against Hardware Fault Cryptanalysis
Authors: Sung-Ming Yen, Seungjoo Kim, Seongan Lim, Sang-Jae Moon
Venue: IEEE Transactions on Computers (2003)

This article considers the problem of how to prevent the fast RSA signature and decryption computation with residue number system (or called the CRT-based approach) speedup from a hardware fault cryptanalysis in a highly reliable and efficient approach. The CRT-based speedup for RSA signature has been widely adopted as an implementation standard ranging from large servers to very tiny smart IC cards. However, given a single erroneous computation result, a hardware fault cryptanalysis can totally break the RSA system by factoring the public modulus. Some countermeasures by using a simple verification function (e.g., raising a signature to the power of public key) or fault detection (e.g., an expanded modulus approach) have been reported in the literature; however, it will be pointed out in this paper that very few of these existing solutions are both sound and efficient. Unreasonably, in these methods, they assume that a comparison instruction will always be fault-free when developing countermeasures against hardware fault cryptanalysis. Researches show that the expanded modulus approach proposed by Shamir is superior to the approach of using a simple verification function when other physical cryptanalysis (e.g., timing cryptanalysis) is considered. So, we intend to improve Shamir's method. In this paper, the new concepts of fault infective CRT computation and fault infective CRT recombination are proposed. Based on the new concepts, two novel protocols are developed with rigorous proof of security. Two possible parameter settings are provided for the protocols. One setting is to select a small public key e and the proposed protocols can have comparable performance to Shamir's scheme. The other setting is to have better performance than Shamir's scheme (i.e., having comparable performance to conventional CRT speedup), but with a large public key. Most importantly, we wish to emphasize the importance of developing and proving the security of physically secure protocols without relying on unreliable or unreasonable assumptions, e.g., always fault-free instructions. In this paper, related protocols are also considered and are carefully examined to point out possible weaknesses.
Constrained Maximum-Entropy Sampling
Authors: Jon Lee
Venue: Operations Research (1998)

A fundamental experimental design problem is to select a most informative subset, having prespecified size, from a set of correlated random variables. Instances of this problem arise in many applied domains such as meteorology, environmental statistics, and statistical geology. In these applications, observations can be collected at different locations and, possibly, at different times. Information is measured by "entropy." Practical situations have further restrictions on the design space. For example, budgetary limits, geographical considerations, as well as legislative and political considerations may restrict the design space in a complicated manner. Using techniques of linear algebra, combinatorial optimization, and convex optimization, we develop upper and lower bounds on the optimal value for the Gaussian case. We describe how these bounds can be integrated into a branch-and-bound algorithm for the exact solution of these design problems. Finally, we describe how we have implemented this algorithm, and we present computational results for estimated covariance matrices corresponding to sets of environmental monitoring stations in the Ohio Valley of the United States.
Review of "On the internet: Thinking in action" by Hubert Dreyfus, Routledge press, 2001
Venue: Ubiquity (2002)

Life and learning on the Net through the eyes of a philosopher.
Ethnographic interviews guide design of ford vehicles website
Authors: Lori Anschuetz, Stephanie Rosenbaum
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This case study describes ethnographic interviews with vehicle buyers to learn how they make purchase decisions. The research was conducted for J. Walter Thompson (JWT), the digital design agency of the Ford Division of the Ford Motor Company; the authors faced challenges of tight schedule, limited budget, and difficulties in finding suitable participants. We nevertheless obtained valuable data that helped JWT refine the Ford Vehicles website.
Symbolic model checking of Dual Transition Petri Nets
Authors: Mauricio Varea, Bashir M. Al-Hashimi, Luis A. Cortés, Petru Eles, Zebo Peng
Venue: Proceedings of the tenth international symposium on Hardware/software codesign (2002)

This paper describes the formal verification of the recently introduced Dual Transition Petri Net (DTPN) models [12], using model checking techniques. The methodology presented addresses the symbolic model checking of embedded systems behavioural properties, expressed in either computation tree logics (CTL) or linear temporal logics (LTL). The embedded system specification is given in terms of DTPN models, where elements of the model are captured in a four-module library which implements the behaviour of the model. Key issues in the development of the methodology are the heterogeneity and the nondeterministic nature of the model. This is handled by introducing some modifications in both structure and behaviour of the model, thus reducing the points of nondeterminism. Several features of the methodology are discussed and two examples are given in order to show the validity of the model.
Asynchronous learning by emotions and cognition
Authors: Sandra Clara Gadanho, Luis Custódio
Venue: Proceedings of the seventh international conference on simulation of adaptive behavior on From animals to animats (2002)

The existence of emotion and cognition as two interacting systems, both with important roles in decision-making, has been advocated by neurophysiological research (LeDoux, 1998; Damasio, 1994). Following this idea, this paper proposes the ALEC agent architecture which has both emotion and cognition learning capabilities to adapt to real-world environments. These two learning mechanisms embody very different properties which can be related with those of natural emotion and cognitive systems.Experimental results show that both systems contribute positively for the learning performance of the agent.
Solving a Truck Dispatching Scheduling Problem Using Branch-And-Cut
Authors: Robert E. Bixby, Eva K. Lee
Venue: Operations Research (1998)

A branch-and-cut IP solver is developed for a class of structured 0/1 integer programs arising from a truck dispatching scheduling problem. This problem involves a special class of knapsack equality constraints. Families of facets for the polytopes associated with individual knapsack constraints are identified. In addition, a notion of "conflict graph" is utilized to obtain an approximating node-packing polytope for the convex hull of all 0/1 solutions. The branch-and-cut solver generates cuts based on both the knapsack equality constraints and the approximating node-packing polytope, and incorporates these cuts into a tree-search algorithm that uses problem reformulation and linear programming-based heuristics at each node in the search tree to assist in the solution process. Numerical experiments are performed on large-scale real instances supplied by Texaco Trading & Transportation, Inc. The optimal schedules correspond to cost savings for the company and greater job satisfaction for drivers due to more balanced work schedules and income distribution.
A practical approach to model long MIS interconnects in VLSI circuits
Authors: Zhong-Fang Jin, Jean-Jacques Laurin, Yvon Savaria
Venue: IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2002)

In this paper, a practical approach to model metal-insulator-semiconductor (MIS) interconnects is presented, with focus on the microstrip configuration. Starting from a one-dimensional (1-D) electromagnetic field analysis, we first extend the validity range of some closed-form expressions from 1-D to two-dimensional (2-D) and present an original RLCG-B model with five equivalent circuit parameters. These parameters, which depend on two effective widths of the physical metal strip, can be frequency dependent because of the skin effect and the dielectric losses. The original RLCG-B model is then modified and implemented with seven frequency-independent circuit parameters. These parameters are computed by analytical equations. Numerical simulations are used to validate the original and modified RLCG-B models. A formula to allow comparison of various interconnect models in the time domain is proposed. Comparisons based on this formula are presented for a single transmission line with source resistance, Rs, and load capacitance, CL. Such comparisons are more meaningful in VLSI applications than comparisons of characteristics derived from swept-frequency per-unit-length parameters.
Novel JPEG 2000 Compliant DWT and IWT VLSI Implementations
Authors: Maurizio Martina, Guido Masera, Gianluca Piccinini, Maurizio Zamboni
Venue: Journal of VLSI Signal Processing Systems (2003)

This paper proposes two JPEG 2000 compliant architectures: one for DWT (Discrete Wavelet Transform) and one for IWT (Integer Wavelet Transform) implementation. First of all some theoretical issues about DWT and IWT are discussed, then, starting from transforms characteristics, the architectures are presented showing both performance and cost. In the literature many DWT architectures have been proposed&semi; our implementation is a new architecture that computes the DWT using filters of interest for the forthcoming JPEG 2000 standard. Moreover, we propose a Lifting Scheme based architecture for IWT, JPEG 2000 compliant too. The proposed architectures are able to support real-time streams: the DWT one, which is made of 20,000 cells, with an input throughput of 160 Msamples per second and a clock frequency of 160 MHz, the IWT one, consisting of 50,000 cells, with an input throughput of 4.5 Msamples per second and an internal clock frequency of 108 MHz.