ppxscal/embedding_network huggingface dataset:
K-loops derived from Frobenius groups
Authors: H. Karzel, Silvia Pianta, Elena Zizioli
Venue: Discrete Mathematics (2002)

We consider a generalization of the representation of the so-called co-Minkowski plane (due to H. and R. Struve) to an abelian group (V,+) and a commutative subgroup G of Aut(V,+). If P = G × V satisfies suitable conditions then an invariant reflection structure (in the sense of Karzel (Discrete Math. 208/209 (1999) 387-409)) can be introduced in P which carries the algebraic structure of K-loop on P (cf. Theorem 1). We investigate the properties of the K-loop (P,+) and its connection with the semi-direct product of V and G. If G is a fixed point free automorphism group then it is possible to introduce in (P,+) an incidence bundle in such a way that the K-loop (P,+) becomes an incidence fibered loop (in the sense of Zizioli (J. Geom. 30 (1987) 144-151)) (cf. Theorem 3).
Producing reliable software: an experiment
Authors: Carol Smidts, Xin Huang, James C. Widmaier
Venue: Journal of Systems and Software (2002)

A customer of high assurance software recently sponsored a software engineering experiment in which a small real-time software system was developed concurrently by two popular software development methodologies. One company specialized in the state-of-the-practice waterfall method rated at a Capability Maturity Model Level 4. A second developer employed his mathematically based formal method with automatic code generation. As specified in separate contracts, C++ code plus development documentation and process and product metrics (errors) were to be delivered. Both companies were given identical functional specifications and agreed to a generous and equal cost, schedule, and explicit functional reliability objectives. At conclusion of the experiment an independent third party determined through extensive statistical testing that neither methodology was able to meet the user's reliability objectives within cost and schedule constraints. The metrics collected revealed the strengths and weaknesses of each methodology and why they were not able to reach customer reliability objectives. This paper will explore the specification for the system under development, the two development processes, the products and metrics captured during development, the analysis tools and testing techniques used by the third party, and the results of a reliability and process analysis.
Where now for development methodologies?
Authors: David E. Avison, Guy Fitzgerald
Venue: Communications of the ACM (2003)

The current swirl of diversity could signal a return to the days of ad hoc systems development, lack of formalmethodology, and consequent increase in failure.
Computational Medicine: Bioelectric Field Problems
Authors: Christopher R. Johnson, Robert S. MacLeod, Michael A. Matheson
Venue: Computer (1993)

Applications of large-scale computer modeling and simulation to a class of bioelectric field problems in a variety of biomedical research areas, from single cells to full human structures, are described. The authors focus on a specific subset of bioelectric field problems that have applications in electrocardiography and electroencephalography. The physics and physiology of bioelectric volume conductors are introduced. A specific computational example and the authors' view on the future direction of computational medicine are presented.
Performance of Carrier Sense Multiple Access with Collision Avoidance Protocols in Wireless LANs
Authors: Jae Hyun Kim, Jong Kyu Lee
Venue: Wireless Personal Communications: An International Journal (1999)

The performance of Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) protocols, which is adopted as a draft standard in IEEE 802.11, is analyzed in the view of throughput and packet delay. We consider three kinds of CSMA/CA protocols, which include Basic, Stop-and-Wait and 4-Way Handshake CSMA/CA, and introduce a theoretical analysis for them. First, we consider that a network consists of a finite population and then expand to an infinite population model. We model the CSMA/CA protocol as a hybrid protocol of a 1-persistent CSMA and a p-persistent CSMA protocol. We calculate the throughput and packet delay for three kinds of CSMA/CA protocols and verify analytical results by computer simulation. We have found that 4-Way Handshake CSMA/CA shows better performance than those of other two type CSMA/CA in high traffic load and analytical results are very close to simulation ones.
Design and Evaluation of Hardware Strategies for Reconfiguring Hypercubes and Meshes Under Faults
Authors: P. Banerjee, M. Peercy
Venue: IEEE Transactions on Computers (1994)

This paper discusses the design of two reconfiguration strategies for distributed memory multicomputer architectures under failures. The specific architectures to which we apply the techniques are hypercubes and meshes. The first scheme uses spare processors attached to certain processors in the hypercube or mash using a novel embedding technique. The second approach places spare processors along specific links in the hypercube or mesh. Both schemes involve the mapping of logical links of a virtual machine onto a set of physical links in the final reconfigured machine and hence suffer some performance degradation. We characterize the performance degradation through trace-driven simulation of real applications running on the faulty and reconfigured system. We find that the schemes have high reliability, suffer little degradation in performance, and are very low in cost.
Integration of copper with an organic low-k dielectric in 0.12-&#x00B5;m node interconnect
Authors: M. Fayolle, G. Passemard, M. Assous, D. Louis, A. Beverina, Y. Gobil, J. Cluzel, L. Arnaud
Venue: Microelectronic Engineering (2002)

Today, copper and low-k dielectric are required to reduce interconnect delay and decrease parasitic capacitance. This paper presents the integration of copper with an organic low-k dielectric (k = 2.7) and is focused on the adaptation of the processes required when switching from SiO2 to this pure organic dielectric. After integration in a dual metal level interconnect for 0.12-µm generation, it is shown that good electrical results are obtained (100% yield for 0.4-µm pitch, via resistance > 1 Ω, capacitance reduction of 40% compared to Cu/SiO2 structures), but care must be taken when integrating this low-k material due to its low thermo-mechanical property and sensibility to moisture absorption.
Data on Air: Organization and Access
Authors: T. Imielinski, S. Viswanathan, B. r. Badrinath
Venue: IEEE Transactions on Knowledge and Data Engineering (1997)

Organizing massive amount of data on wireless communication networks in order to provide fast and low power access to users equipped with palmtops, is a new challenge to the data management and telecommunication communities. Solutions must take under consideration the physical restrictions of low network bandwidth and limited battery life of palmtops. This paper proposes algorithms for multiplexing clustering and nonclustering indexes along with data on wireless networks. The power consumption and the latency for obtaining the required data are considered as the two basic performance criteria for all algorithms. First, this paper describes two algorithms namely, (1, m) Indexing and Distributed Indexing, for multiplexing data and its clustering index. Second, an algorithm called Nonclustered Indexing is described for allocating static data and its corresponding nonclustered index. Then, the Nonclustered indexing algorithm is generalized to the case of multiple indexes. Finally, the proposed algorithms are analytically demonstrated to lead to significant improvement of battery life while retaining a low latency.
Design of Simple-Structure Linear Controllers
Authors: V. A. Mozzhechkov
Venue: Automation and Remote Control (2003)

Algorithms for designing dynamic simple-structure controllers for a linear system with scalar control and vector feedback are designed. A simple-structure controller is such that no element can be eliminated from its description without violating the conditions defining the quality requirements of the designed system.
Finding Consistent Global Checkpoints in a Distributed Computation
Authors: D. Manivannan, Robert H. B. Netzer, Mukesh Singhal
Venue: IEEE Transactions on Parallel and Distributed Systems (1997)

Consistent global checkpoints have many uses in distributed computations. A central question in applications that use consistent global checkpoints is to determine whether a consistent global checkpoint that includes a given set of local checkpoints can exist. Netzer and Xu [16] presented the necessary and sufficient conditions under which such a consistent global checkpoint can exist, but they did not explore what checkpoints could be constructed. In this paper, we prove exactly which local checkpoints can be used for constructing such consistent global checkpoints. We illustrate the use of our results with a simple and elegant algorithm to enumerate all such consistent global checkpoints.
Proof of the Correctness of EMYCIN Sequential Propagation Under Conditional Independence Assumptions
Authors: Xudong Luo, Chengqi Zhang
Venue: IEEE Transactions on Knowledge and Data Engineering (1999)

In this paper, we prove that under the assumption of conditional independence, the EMYCIN formula for sequential propagation can be derived strictly from the definition of the certainty factor according to probability theory. We already have known that Adams [1] and Schocken [15] have proved that the EMYCIN formula for parallel propagation is partially consistent with probability theory. Our result supplements their contribution and, together with theirs, explains why the EMYCIN model has been working reasonably well.
REDFIT: estimating red-noise spectra directly from unevenly spaced paleoclimatic time series
Authors: Michael Schulz, Manfred Mudelsee
Venue: Computers Geosciences (2002)

Paleoclimatic time series are often unevenly spaced in time, making it difficult to obtain an accurate estimate of their red-noise spectrum. A Fortran 90 program (REDFIT) is presented that overcomes this problem by fitting a first-order autoregressive (AR1) process, being characteristic for many climatic processes, directly to unevenly spaced time series. Hence, interpolation in the time domain and its inevitable bias can be avoided. The program can be used to test if peaks in the spectrum of a time series are significant against the red-noise background from an AR1 process. Generated and paleoclimatic time series are used to demonstrate the capability of the program.
Multimedia MedNet
Authors: Robert Simon, Donald Krieger, Taieb Znati, Raymond Lofink, Robert J. Sclabassi
Venue: Computer (1995)

This paper describes MultiMedia MedNet (MedNet), a distributed collaborative medical multimedia system. MedNet combines neurophysiological, audio and video data in a real-time remote diagnostic and monitoring system, and is used on a daily basis in seven hospitals at the University of Pittsburgh Medical Center. MedNet provides an interesting example of a working distributed and collaborative multimedia system in an exacting environment, involving data types and manipulations that are broader and more demanding than those found in a typical teleconferencing application. Phase I MedNet incorporates digital signal processing, along with distributed systems tools for group communication, multimedia file access and storage, and software for the manipulation and display of neurophysiological information. Communication control in Phase II is managed by a multimedia group process protocol called the Distributed InterProcess Communication System (DIPCS) that is scalable to a WAN.
Computers Are from Mars, Organisms Are from Venus
Authors: Junhyong Kim
Venue: Computer (2002)

Biology and computer science share a natural affinity. Physicist Erwin Schrödinger envisioned life as an aperiodic crystal, observing that the organizing structure of life is neither completely regular, like a pure crystal, nor completely chaotic and without structure, like dust in the wind. Perhaps this is why biological information has never satisfactorily yielded to classical mathematical analysis.Machine computations combine elegant algorithms with brute-force calculations--which seems a reasonable approach to this aperiodic structure. Likewise, computing seeks to create a machine that can flexibly solve diverse problems. In nature, such plastic problem solving resides uniquely in the domain of organic matter. Thus, examining how organisms solve problems can lead to new computation- and algorithm-development approaches that devour the problems that are so easy to approach using a computer, yet so difficult to tackle in the laboratory.
Reduction of simple semi-conditional grammars with respect to the number of conditional productions
Authors: Alexander Meduna Martin Svec
Venue: Acta Cybernetica (2002)

The present paper discusses the descriptional complexity of simple semi-conditional grammars with respect to the number of conditional productions. More specifically, it demonstrates that for every phrase-structure grammar, there exists an equivalent simple semi-conditional grammar that has no more than twelve conditional productions.
Compile-Time Partitioning of Iterative Parallel Loops to Reduce Cache Coherency Traffic
Authors: S. G. Abraham, D. E. Hudak
Venue: IEEE Transactions on Parallel and Distributed Systems (1991)

Adaptive data partitioning (ADP) which reduces the execution time of parallel programs by reducing interprocessor communication for iterative parallel loops is discussed. It is shown that ADP can be integrated into a communication-reducing back end for existing parallelizing compilers or as part of a machine-specific partitioner for parallel programs. A multiprocessor model to analyze program execution factors that lead to interprocessor communication and a model for the iterative parallel loop to quantify communication patterns within a program are defined. A vector notation is chosen to quantify communication across a global data set. Communication parameters are computed by examining the indexes of array accesses and are adjusted to reflect the underlying system architecture by compensating for cache line sizes. These values are used to generate rectangular and hexagonal partitions that reduce interprocessor communication.
Weight Hierarchies of Linear Codes Satisfying the ChainCondition
Authors: Wende Chen, Torleiv Klove
Venue: Designs, Codes and Cryptography (1998)

The weight hierarchy of a linear [n,k;q] code C over GF(q) is the sequence (d_1,d_2, &mldr;,d_k) where d_r is the smallest support of an r&ndash;dimensional subcode of C. By explicit construction, it is shown that if a sequence (a_1,a_2, &mldr;,a_k) satisfies certain conditions, then it is the weight hierarchy of a code satisfying the chain condition.
Classification and evaluation of defects in a project retrospective
Authors: Marek Leszak, Dewayne E. Perry, Dieter Stoll
Venue: Journal of Systems and Software (2002)

There are three interdependent factors that drive our development processes: interval, quality and cost. As market pressures continue to demand new features ever more rapidly, the challenge is to meet those demands while increasing, or at least not sacrificing, quality. One advantage of defect prevention as an upstream quality improvement practice is the beneficial effect it can have on interval: higher quality early in the process results in fewer defects to be found and repaired in the later parts of the process, thus causing an indirect interval reduction.We report a retrospective analysis of the defect modification requests (MRs) discovered while building, testing, and deploying a release of a network element as part of an optical transmission network. The study consists of three investigations: a root-cause defect analysis (RCA) study, a process metric study, and a code complexity investigation. Differing in the quantities that we anticipate to be related to found defects, they all have in common the goal of identifying early quality indicators.The core of this threefold study is the root-cause analysis. We present the experimental design of this case study in some detail and its integration into the development process. We discuss the novel approach we have taken to defect and root cause classification and the mechanisms we have used for randomly selecting the MRs, to analyze and collecting the analyses via a web interface. We present the results of our analyses of the MRs and describe the defects and root causes that we found, and delineate the countermeasures created either to prevent those defects and their root causes or to detect them at the earliest possible point in the development process. We conclude the report on the root-cause analysis with lessons learned from the case study and from our experiences during subsequent usage of this analysis methodology for in-process measurement.Beyond the root-cause analysis, we first present our findings on the correlation between defects detected and the adherence to our development process. Second, we report on our experience with analyzing static code properties and their relation to observed defect numbers and defect densities.
A probabilistic definition of a nonconvex fuzzy cardinality
Authors: Miguel Delgado, Daniel Sánchez, María J. Martín-Bautista, María Amparo Vila
Venue: Fuzzy Sets and Systems (2002)

The existing methods to assess the cardinality of a fuzzy set with finite support are intended to preserve the properties of classical cardinality. In particular, the main objective of researchers in this area has been to ensure the convexity of fuzzy cardinalities, in order to preserve some properties based on the addition of cardinalities, such as the additivity property. We have found that in order to solve many real-world problems, such as the induction of fuzzy rules in Data Mining, convex cardinalities are not always appropriate. In this paper, we propose a possibilistic and a probabilistic cardinality of a fuzzy set with finite support. These cardinalities are not convex in general, but they are most suitable for solving problems and, contrary to the generalizing opinion, they are found to be more intuitive for humans. Their suitability relies mainly on the fact that they assume dependency among objects with respect to the property "to be in a fuzzy set". The cardinality measures are generalized to relative ones among pairs of fuzzy sets. We also introduce a definition of the entropy of a fuzzy set by using one of our probabilistic measures. Finally, a fuzzy ranking of the cardinality of fuzzy sets is proposed, and a definition of graded equipotency is introduced.
Visualizing dynamic molecular conformations
Authors: Johannes Schmidt-Ehrenberg, Daniel Baum, Hans Christian Hege
Venue: Proceedings of the conference on Visualization '02 (2002)

The bioactivity of a molecule strongly depends on its metastable conformational shapes and the transitions between these. Therefore, conformation analysis and visualization is a basic prerequisite for the understanding of biochemical processes.We present techniques for visual analysis of metastable molecular conformations. Core of these are flexibly applicable methods for alignment of molecular geometries, as well as methods for depicting shape and 'fuzziness' of metastable conformations. All analysis tools are provided in an integrated working environment.The described techniques are demonstrated with pharmaceutically active biomolecules.
Correctness by Construction: Developing a Commercial Secure System
Authors: Anthony Hall, Roderick Chapman
Venue: IEEE Software (2002)

Praxis Critical Systems recently developed a secure certification authority for smart cards that had to satisfy performance and usability requirements while meeting stringent security constraints. The authors used a systematic process from requirements elicitation through formal specification, user interface prototyping, rigorous design, and coding to ensure these objectives' achievement. They show how a process that achieves normal commercial productivity can deliver a highly reliable system that meets all its throughput and us-ability goals.
On a Conjecture of R. P. Stanley; Part II--Quotients Modulo Monomial Ideals
Authors: Joachim Apel
Venue: Journal of Algebraic Combinatorics: An International Journal (2003)

In 1982 Richard P. Stanley conjectured that any finitely generated \Bbb Zn-graded module M over a finitely generated \Bbb Nn-graded \Bbb K-algebra R can be decomposed as a direct sum M &equals; &oplus;i &equals; 1t &nu;iSi of finitely many free modules &nu;iSi which have to satisfy some additional conditions. Besides homogeneity conditions the most important restriction is that the Si have to be subalgebras of R of dimension at least depth M.We will study this conjecture for modules M &equals; R/I, where R is a polynomial ring and I a monomial ideal. In particular, we will prove that Stanley's Conjecture holds for the quotient modulo any generic monomial ideal, the quotient modulo any monomial ideal in at most three variables, and for any cogeneric Cohen-Macaulay ring. Finally, we will give an outlook to Stanley decompositions of arbitrary graded polynomial modules. In particular, we obtain a more general result in the 3-variate case.
Word processing services for a university: experiences at Stanford
Authors: J. Siegman, J. Sandelin
Venue: Proceedings of the 7th annual ACM SIGUCCS conference on User services (1979)

Approaches to the technical, political, economic and human factors issues in planning and provision of word processing services for a university.While usage of word processing services at Stanford's computer center has continued to grow, the University has experienced a proliferation of commercial stand alone equipment. After over a year of guiding administrative offices and academic departments in selecting among the alternatives, the interdepartmental Committee on Office Systems and Technology (COST) is preparing a recommendation for a campus-wide system.