ppxscal/embedding_network huggingface dataset:
Optimal Lead Time Policies
Authors: Mark L. Spearman, Rachel Q. Zhang
Venue: Management Science (1999)

This paper examines two due-date setting problems first studied by Wein (1991). The first problem seeks to minimize the average due-date lead time (due-date minus arrival date) of jobs subject to a constraint on the fraction of tardy jobs (Problem I) while the second uses the same objective subject to a constraint on average job tardiness (Problem II). We show that under very general conditions, Problem I leads to unethical practice (i.e., quote lead times for which there is no hope to achieve when the system is highly congested) while Problem II results in policies that quote lead times that are monotonically increasing with the congestion level. Furthermore, we prove that Problem II is equivalent to a policy that is widely used and is easy to compute. This policy quotes lead times that guarantee the same serviceability level (the fraction of tardy jobs) to all jobs.
Modeling a Hardware Synthesis Methodology in Isabelle
Authors: David Basin, Stefan Friedrich
Venue: Formal Methods in System Design (1999)

Formal Synthesis is a methodology developed at the university of Kent for combining circuit design and verification, where a circuit is constructed from a proof that it meets a given formal specification. We have reinterpreted this methodology in ISABELLE&lsquo;S theory of higher-order logic so that circuits are incrementally built during proofs using higher-order resolution. Our interpretation simplifies and extends Formal Synthesis both conceptually and in implementation. It also supports integration of this development style with other proof-based synthesis methodologies and leads to techniques for developing new classes of circuits, e.g., recursive descriptions of parametric designs.
The use of the Internet in the teaching process
Authors: Dariusz Put, Janusz Stal, Marek Zurowicz
Venue: ACM SIGCSE Bulletin (1999)

The aim of this project is to present a teaching method based on the HTTP protocol. The main goal of this method is to aid the self-study process with the use of interactive pages based on the HTTP protocol. Such pages are generated for each student individually, depending on his progress in internalising knowledge.
The Generic Number of Invariant Zeros of a Structured Linear System
Authors: Jacob vander Woude
Venue: SIAM Journal on Control and Optimization (1999)

In this paper we consider a structured linear system represented by means of a directed graph. We present a graph theoretic method to compute the generic number of invariant zeros of the corresponding Rosenbrock matrix. The method is based on a fundamental decomposition of the directed graph representing the structured system. The generic number of invariant zeros is important in generic versions of problems involving controllability and pole placement.
The Linear Extension Diameter of a Poset
Authors: Stefan Felsner, Klaus Reuter
Venue: SIAM Journal on Discrete Mathematics (1999)

The distance between two permutations of the same set X is the number of pairs of elements that are in different order in the two permutations. Given a poset $P=(X,\leq)$, a pair $L_1,L_2$ of linear extensions is called a diametral pair if it maximizes the distance among all pairs of linear extensions of P. The maximal distance is called the linear extension diameter of P and is denoted led(P). Alternatively led(P) is the maximum number of incomparable pairs of a two-dimensional extension of P. In the first part of the paper we discuss upper and lower bounds for led(P). These bounds relate led(P) to well-studied parameters like dimension and height. We prove that led(P) is a comparability invariant and determine the linear extension diameter for the class of generalized crowns. For the Boolean lattices we have partial results.A diametral pair generates a minimal two-dimensional extension of P or, equivalently, a maximal interval in the graph of linear extensions of P. Studies of such intervals lead to the definition of new classes of linear extensions. We give three characterizations of the class of extremal linear extensions which contains the greedy linear extensions. With complementary linear extensions we introduce a class contained in the set of super-greedy linear extensions. The complementary linear extension of $L$ is the linear extension L* obtained by taking the reverse of L as a priority list in the generic algorithm for linear extensions. A complementary pair is a pair L,M of linear extensions with M=L* and L=M*. Iterations of the complementary mapping starting from an arbitrary linear extension eventually lead to a complementary pair.
Self-Stabilizing Algorithms for Finding Centers and Medians of Trees
Authors: Steven C. Bruell, Sukumar Ghosh, Mehmet Hakan Karaata, Sriram V. Pemmaraju
Venue: SIAM Journal on Computing (1999)

Locating a center or a median in a graph is a fundamental graph-theoretic problem. Centers and medians are especially important in distributed systems because they are ideal locations for placing resources that need to be shared among different processes in a network. This paper presents simple self-stabilizing algorithms for locating centers and medians of trees. Since these algorithms are self-stabilizing, they can tolerate transient failures. In addition, they can automatically adjust to a dynamically changing tree topology. After the algorithms are presented, their correctness is proven and upper bounds on their time complexity are established. Finally, extensions of our algorithms to trees with arbitrary, positive edge costs are sketched.
Optical IP routers: design and performance issues under self-similar traffic
Authors: Lakshman S. Tamil, Francesco Masetti, Tom McDermott, Gerardo Castanon, An Ge, Ljubiša Tančevski
Venue: Journal of High Speed Networks (1999)

The increased data traffic experienced today and the projected increase in the data traffic in the future demand exploration of novel approaches to IP transport such as transport of IP traffic over optics. The bimodal nature of the IP traffic colon; short packets which are typical of transactional-style flows and large packets or bursts which are encountered in the transport of large data blocks requires, design of routers that are capable of routing packets with variable lengths efficiently. In this paper, we discuss the design aspects of such all-optical IP-routers. The broadcast and select architecture is a prime candidate for implementing optical IP routers. Construction of optical routers with buffering, wavelength conversion and multipath routing are considered. The merits and demerits of all these cases and the effect of buffer size, wavelength conversion and multiple-path routing on the blocking probability and probability of packet loss are discussed.
&ldquo;It's infrastructure all the way down&rdquo; (keynote address)
Authors: Susan Leigh Star
Venue: Proceedings of the fifth ACM conference on Digital libraries (2000)

What is infrastructure and how shall we know it? As libraries move partly to desktops, one of the challenges facing the digital library community becomes designing for distributed use across many kinds of local circumstance. These circumstances vary widely in terms of people, resources, support, and technical configurations. Designing for this variety means reconceptualizing &ldquo;user meets screen&rdquo; as &ldquo;user meets infrastructure.&rdquo; This requires scaling up traditional design and evaluation methods, as well as a richer knowledge of the organizational and historical contexts of use. This talk addresses some of the methodological challenges involved in such work.Susan Leigh Star (Leigh) is Professor of Communication at the University of California, San Diego. She received her Ph.D in sociology of science and medicine from UC San Francisco. Before coming to UCSD in 1999, she was Professor of Information Science at the University of Illinois, Urbana-Champaign. She has also taught at UC Irvine and Keele University, in England, and several universities in Scandinavia as guest professor. Much of her research has been on the social implications and design of large-scale technology, especially information technology. Among her publications are "The Cultures of Computing" (ed) (Blackwell, 1995), "Regions of the Mind: Brain Research and the Quest for Scientific Certainty" (Stanford 1989), and (with Geoffrey Bowker), "Sorting Things Out: Classification and Its Consequences" (MIT, 1999). She is volume editor for Science and Technology for the Women's Studies International Encyclopedia (edited by Cheris Kramarae and Dale Spender), forthcoming from Routledge in 2000. Her current research concerns ethical and methodological dilemmas in on-line research with human subjects.
Outcomes Research and Community Health Information Systems
Authors: Carl H. Slater
Venue: Journal of Medical Systems (1999)

The developments in outcomes research and community health information systems are pursuing essentially parallel courses in this country, and yet integrating the lessons from each other could yield more informed health policy decisions. This article provides the linkage between these two developing fields, discusses indicators of community health, describes several approximations to an outcomes-based community health information system in this country, and specifies a model (POPULIS) of such a system from Canada. Although POPULIS can serve as a prototype for health policy decision making, the outcomes-based community health information system, which can be constructed in this country, is constrained by the pluralistic system of health care we have and the lack of any centralized planning about health.
Dynamic channel assignment in wireless communication networks
Authors: Anna Haj Hać, Chunlei Haj Mo
Venue: International Journal of Network Management (1999)

We propose a new Cochannel information based Dynamic Channel Assignment &lpar;CDCA&rpar; strategy for small and microcell systems and a new Group Dynamic Channel Assignment &lpar;GDCA&rpar; strategy which handles multichannel traffic in wireless networks. Copyright &copy; 1999 John Wiley Sons, Ltd.
A chase too far?
Authors: Lucian Popa, Alin Deutsch, Arnaud Sahuguet, Val Tannen
Venue: ACM SIGMOD Record (2000)

In a previous paper we proposed a novel method for generating alternative query plans that uses chasing (and back-chasing) with logical constraints. The method brings together use of indexes, use of materialized views, semantic optimization and join elimination (minimization). Each of these techniques is known separately to be beneficial to query optimization. The novelty of our approach is in allowing these techniques to interact systematically, eg. non-trivial use of indexes and materialized views may be enabled only by semantic constraints. We have implemented our method for a variety of schemas and queries. We examine how far we can push the method in term of complexity of both schemas and queries. We propose a technique for reducing the size of the search space by &ldquo;stratifying&rdquo; the sets of constraints used in the (back)chase. The experimental results demonstrate that our method is practical (i.e., feasible and worthwhile).
Optimization of multiple-relation multiple-disjunct queries
Authors: M. Muralikrishna, David J. DeWitt
Venue: Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1988)

In this paper we discuss the optimization of multiple-relation multiple-disjunct queries in a relational database system. Since optimization techniques for conjunctive (single disjunct) queries in relational databases are well known [Smith75, Wong76, Selinger79, Yao79, Youssefi79], the natural way to evaluate a multiple-disjunct query was to execute each disjunct independently [Bernstein81, Kerschberg82] However, evaluating each disjunct independently may be very inefficient. In this paper, we develop methods that merge two or more disjuncts to form a term. The advantage of merging disjuncts to form terms lies in the fact that each term can be evaluated with a single scan of each relation that is present in the term. In addition, the number of times a join is performed will also be reduced when two or more disjuncts are merged. The criteria for merging a set of disjuncts will be presented. As we will see, the number of times each relation in the query is scanned will be equal to the number of terms. Thus, minimizing the number of terms will minimize the number of scans for each relation. We will formulate the problem of minimizing the number of scans as one of covering a merge graph by a minimum number of complete merge graphs which are a restricted class of Cartesian product graphs. In general, the problem of minimizing the number of scans is NP-complete. We present polynomial time algorithms for special classes of merge graphs. We also present a heuristic for general merge graphs. Throughout this paper, we will assume that no relations have any indices on them and that we are only concerned with reducing the number of scans for each relation present in the query. What about relations that have indices on them? It turns out that our performance metric of reducing the number of scans is beneficial even in the case that there are indices. In [Muralikrishna88] we demonstrate that when optimizing single-relation multiple-disjunct queries, the cost (measured in terms of disk accesses) may be reduced if all the disjuncts are optimized together rather than individually. Thus, our algorithm for minimizing the number of terms is also very beneficial in cases where indices exist
Virtual screening: a step towards a sparse partial inductance matrix
Authors: A. J. Dammers, N. P. van der Meijs
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

We extend the partial inductance concept by replacing the magnetic interaction between open filaments i and j by that between filament j and a (finite) closed loop, formed by connecting the endpoints of a filament pair (i-i&prime;). The secondary filament i' is constructed by radial projection of filament i onto a cylindrical shell around filament j. We show that, although individual partial inductance values are modified, the inductive behaviour of the full circuit is invariant. Mutual inductances of distant filaments are particularly reduced, because the far field of a conductor loop falls off much faster than that of a single filament. Therefore, it is expected that subsequent removal of such transformed off-diagonal elements from the partial inductance matrix has less effect on the overall inductive properties, so our method provides a tool to enhance robustness under matrix sparsification. We call our method &ldquo;virtual screening&rdquo;, because the screening filaments {i&prime;} are not physically present. Symmetry of the inductance matrix is preserved for orthogonal networks only.We also present an extension of our method to a more general class of shells. This allows a detailed comparison of the virtual screening method and the &ldquo;potential shift-truncate method&rdquo;, introduced with spherical equipotential shells [Krauter et al. ICCAD'95] and extended to ellipsoidal equipotential shells recently [Beattie et al. IEDM'98]. We find strong similarities, but also differences. An interesting result is the fact that the virtual screening method with tubular shells applied to orthogonal networks can be interpreted as a generalization of the potential shift-truncate method to non-equipotential shells, which also implies that preservation of stability is guaranteed.Some numerical results, sustaining the ideas behind our method, conclude the paper.
Distributed programming with intermediate IDL
Authors: Gary W. Smith, Richard A. Volz
Venue: Proceedings of the ninth international workshop on Real-time Ada (1999)

Several heterogeneous-language distributed programming systems have been developed which either use an explicit Interface Definition Language (IDL) for the specification of distributed objects or which directly translate server language specifications to corresponding client language representations. In this paper, we present a new approach which combines the advantages of these prior systems. Our approach uses an IDL as an implicit intermediate step in the translation from server to client language rather than as an explicit user-provided definition.
Three for one: role-based access-control management in rapidly changing heterogeneous environments
Authors: Axel Mönkeberg, René Rakete
Venue: Proceedings of the fifth ACM workshop on Role-based access control (2000)

We describe a maintenance tool for role-based access-control (RBAC0, RBAC1 and RBAC2 [1]), implemented in a Swiss bank. Concept and implementation of the system is as far as possible independent of operating system and vendors. The tool supports the maintenance of the access control interface to database systems, operating systems, web server and application systems (e.g. workflow management systems [9], OLAP tools and analytic tools). It is based on the principle of using a system independent access-control specification-language (ADL), a repository for static definition and runtime data, a target system independent access-control command language (CDL) and a set of different target system specific implementations of the access-control maintenance interfaces (TDL). The system is able to maintain the access control interfaces of passive systems (e.g. common DBMS [5],[6],[7] and OS [8],[12],[10]) and supports also the access control mechanism of active systems. Active systems have no own authorization control mechanism implemented. Active systems check the authorization of operations of a particular user by calling a &ldquo;central&rdquo; authorization instance. The system is implemented in Java and SQL and uses the CORBA IIOP communication protocol.
Existence of (q,6,1) Difference Families withq a Prime Power
Authors: K. Chen, L. Zhu
Venue: Designs, Codes and Cryptography (1998)

The existence of a (q,k,1) difference family in GF(q) has been completely solved for k=3, 4, 5. For k=6 fundamental results have been given by Wilson. In this article, we continue the investigation and show that the necessary condition for the existence of a(q,6,1) difference family in GF(q), i.e. q\equiv 1 (mod 30) is also sufficient with one exception of q=61. The method of this paper is to lower Wilson&lsquo;s bound by using Weil&lsquo;s theorem on character sums to exploit Wilson&lsquo;s sufficient conditions for the existence of (q,6,1) difference families. The remaining gap is closed by computer searches.
Correlated load-address predictors
Authors: Michael Bekerman, Stephan Jourdan, Ronny Ronen, Gilad Kirshenboim, Lihu Rappoport, Adi Yoaz, Uri Weiser
Venue: ACM SIGARCH Computer Architecture News (1999)

As microprocessors become faster, the relative performance cost of memory accesses increases. Bigger and faster caches significantly reduce the absolute load-to-use time delay. However, increase in processor operational frequencies impairs the relative load-to-use latency, measured in processor cycles (e.g. from two cycles on the Pentium reg; processor to three cycles or more in current designs). Load-address prediction techniques were introduced to partially cut the load-to-use latency. This paper focuses on advanced address-prediction schemes to further shorten program execution time.Existing address prediction schemes are capable of predicting simple address patterns, consisting mainly of constant addresses or stride-based addresses. This paper explores the characteristics of the remaining loads and suggests new enhanced techniques to improve prediction effectiveness: bull; Context-based prediction to tackle part of the remaining, difficult-to-predict, load instructions. bull; New prediction algorithms to take advantage of global correlation among different static loads. bull; New confidence mechanisms to increase the correct prediction rate and to eliminate costly mispredictions. bull; Mechanisms to prevent long or random address sequences from polluting the predictor data structures while providing some hysteresis behavior to the predictions.Such an enhanced address predictor accurately predicts 67% of all loads, while keeping the misprediction rate close to 1%. We further prove that the proposed predictor works reasonably well in a deep pipelined architecture where the predict-to-update delay may significantly impair both prediction rate and accuracy.
Application of Reconfigurable CORDIC Architectures
Authors: Oskar Mencer, Luc Séméria, Martin Morf, Jean-Marc Delosme
Venue: Journal of VLSI Signal Processing Systems (2000)

Reconfiguration enables the adaption of Coordinate Rotation DIgital Computer (CORDIC) units to the specific needs of sets of applications, hence creating application specific CORDIC-style implementations. Reconfiguration can be implemented at a high level, taking the entire CORDIC unit as a basic cell (CORDIC-cells) implemented in VLSI, or at a low level such as Field-Programmable Gate Arrays (FPGAs). We suggest a design methodology and analyze area/time results for coarse (VLSI) and fine-grain (FPGA) reconfigurable CORDIC units. For FPGAs we implement CORDIC units in Verilog HDL and our object-oriented design environment, PAM-Blox. For CORDIC-cells, multiple reconfigurable CORDIC modules are synthesized with state-of-the-art CAD tools. At the algorithm level we present a case study combining multiple CORDICs based on a geometrical interpretation of a normalized ladder algorithm for adaptive filtering to reduce latency and area of a fully pipelined CORDIC implementation. Ultimately, the goal is to create automatic tools to map applications directly to reconfigurable high-level arithmetic units such as CORDICs.
The Feasibility of Using Automated Data to Assess Guideline-Concordant Care for Schizophrenia
Authors: Teresa J. Hudson, Richard R. Owen, A. Elizabeth Lancaster
Venue: Journal of Medical Systems (1999)

This study examines the feasibility of using automated computer data versus written medical record data to identify patients receiving guideline concordant treatment for schizophrenia. Central elements of care derived from published practice guidelines for schizophrenia were examined for a convenience sample of 28 patients who received acute inpatient treatment. The results showed that automated data were superior to medical record data for identifying some elements of guideline-concordant treatment. Not only were the elements of care examined in this study clinically significant and within the current capabilities of the existing computer information system, but they are also likely related to patient outcomes. Implications for clinical care, future research, and health care quality improvement efforts are discussed.
A Trust Region Method for Nonlinear Programming Based on Primal Interior-Point Techniques
Authors: Todd Plantenga
Venue: SIAM Journal on Scientific Computing (1998)

This paper describes a new trust region method for solving large-scale optimization problems with nonlinear equality and inequality constraints. The new algorithm employs interior-point techniques from linear programming, adapting them for more general nonlinear problems. A software implementation based entirely on sparse matrix methods is described. The software handles infeasible start points, identifies the active set of constraints at a solution, and can use second derivative information to solve problems. Numerical results are reported for large and small problems, and a comparison is made with other large-scale optimization codes.