ppxscal/embedding_network huggingface dataset:
Reconstructing a Generalized Quadrangle from its Distance Two Association Scheme
Authors: Sylvia A. Hobart, Stanley E. Payne
Venue: Journal of Algebraic Combinatorics: An International Journal (1993)

Payne &lsqb;4&rsqb; constructed an association scheme from a generalized quadrangle with a quasiregular point. We show that an association scheme with appropriate parameters and satisfying an assumption about maximal cliques must be one of these schemes arising from a generalized quadrangle.
SIGIR '93: school of library and information science, Univ. of Pittsburgh
Authors: Sherry Koshman
Venue: ACM SIGIR Forum (1993)

The Sixteenth Annual International ACM SIGIR Conference on Research and Development in Information Retrieval was held in Pittsburgh from June 27 to July 1. This conference, with its focus on research, is the premier venue for the discussion of theoretical and practical elements of information retrieval (IR).
New techniques for studying set languages, bag languages and aggregate functions
Authors: Leonid Libkin, Limsoon Wong
Venue: Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1994)

We provide new techniques for the analysis of the expressive power of query languages for nested collections. These languages may use set or bag semantics and may be further complicated by the presence of aggregate functions. We exhibit certain classes of graphs and prove that the properties of these graphs that can be tested in such languages are either finite or cofinite. This result settles the conjectures of Grumbach, Milo, and Paredaens that parity test, transitive closure, and balanced binary tree test are not expressible in bag languages like the PTIME fragment of BALG of Grumbach and Milo and BQL of Libkin and Wong. Moreover, it implies that many recursive queries, including simple ones like the test for a chain, cannot be expressed in a nested relational language even when aggregate functions are available. In an attempt to generalize the finite-cofiniteness result, we study the bounded degree property which says that the number of distinct in- and out-degrees in the output of a graph query does not depend on the size of the input if the input is &ldquo;simple&rdquo;. We show that such a property implies a number of inexpressibility results in a uniform fashion. We then prove the bounded degree property for the nested relational language.
Parallel simulation of a high speed LAN
Authors: R. Rönngren, H. Rajaei, A. Popescu, M. Liljenstam, Y. Ismailov, R. Ayani
Venue: Proceedings of the eighth workshop on Parallel and distributed simulation (1994)

Simulation of communication networks is often time consuming. Parallel simulation may be used to reduce the execution time of such a simulator. However, efficient modeling and simulation of such complex applications is not a trivial task. In this paper, we discuss the results of simulating a multigigabit/s network using both an optimistic and a conservative scheme. Our experimental result on a shared memory multiprocessor indicates that the conservative approach is superior to the optimistic one for this application.
Limits to low-latency communication on high-speed networks
Authors: Chandramohan A. Thekkath, Henry M. Levy
Venue: ACM Transactions on Computer Systems (TOCS) (1993)

The throughput of local area networks is rapidly increasing. For example, the bandwidth of new ATM networks and FDDI token rings is an order of magnitude greater than that of Ethernets. Other network technologies promise a bandwidth increase of yet another order of magnitude in several years. However, in distributed systems, lowered latency rather than increased throughput is often of primary concern. This paper examines the system-level effects of newer high-speed network technologies on low-latency, cross-machine communications. To evaluate a number of influences, both hardware and software, we designed and implemented a new remote procedure call system targeted at providing low latency. We then ported this system to several hardware platforms (DECstation and SPARCstation) with several different networks and controllers (ATM, FDDI, and Ethernet). Comparing these systems allows us to explore the performance impact of alternative designs in the communication system with respect to achieving low latency, e.g., the network, the network controller, the hose architecture and cache system, and the kernel and user-level runtime software. Our RPC system, which achieves substantially reduced call times (170 &mgr;seconds on an ATM network using DECstation 5000/200 hosts), allows us to isolate those components of next-generation networks and controllers that still stand in the way of low-latency communication. We demonstrate that new-generation processor technology and software design can reduce small-packet RPC times to near network-imposed limits, making network and controller design more crucial than ever to achieving truly low-latency communication.
A Rational-Function Identity Related to the Murnaghan&ndash;Nakayama Formula for the Characters of Sn
Authors: Curtis Greene
Venue: Journal of Algebraic Combinatorics: An International Journal (1992)

The Murnaghan&ndash;Nakayama formula for the characters of Sn is derived from Young's seminormal representation, by a direct combinatorial argument. The main idea is a rational function identity which when stated in a more general form involves M&ouml;bius functions of posets whose Hasse diagrams have a planar embedding. These ideas are also used to give an elementary exposition of the main properties of Young's seminormal representations.
RATCHET: real-time address trace compression hardware for extended traces
Authors: Colleen D. Schieber, Eric E. Johnson
Venue: ACM SIGMETRICS Performance Evaluation Review (1994)

The address traces used in computer architecture research are commonly generated using software techniques that introduce time dilations of an order of magnitude or more. Such techniques may also omit classes of memory references that are important for accurate models of computer systems, such as instruction prefetches, operating system references, and interrupt activity.We describe a technique for capturing all classes of references in real time. RATCHET employs trace filtering hardware to reduce the bandwidth and storage requirements that have previously limited the usefulness of hardware-based tracing. In evaluating this technique using the ten SPEC89 benchmark programs running on a Sun-3/60 workstation, we found that a small filter cache achieves compression ratios in the 10-30 range during the startup section of the programs. Traces from the middle sections of the C programs achieved compression ratios of 20-30, while the FORTRAN codes produced ratios of 45-84. Traces from a smaller ionospheric simulator program were compressed by factors of 100.These filtered traces typically represent 36 million contiguous references.
Processing time-constrained aggregate queries in CASE-DB
Authors: Wen-Chi Hou, Gultekin Ozsoyoglu
Venue: ACM Transactions on Database Systems (TODS) (1993)

In this paper, we present an algorithm to strictly control the time to process an estimator for an aggregate relational query. The algorithm implemented in a prototype database management system, called CASE-DB, iteratively samples from input relations, and evaluates the associated estimator until the time quota expires. In order to estimate the time cost of a query, CASE-DB uses adaptive time cost formulas. The formulas are adaptive in that the parameters of the formulas can be adjusted at runtime to better fit the characteristics of a query. To control the use of time quota, CASE-DB adopts the one-at-a-time-interval time control strategy to make a tradeoff between the risks of overspending and the overhead, finally, experimental evaluation of the methodology is presented.
Report on the HISC workshop
Authors: André Heck
Venue: ACM SIGSAM Bulletin (1994)

The Research Institute for Applications of Computer Algebra (RIACA) in Amsterdam, The Netherlands, organized on March 10-11, 1994, an international workshop entitled Human Interaction for Symbolic Computation. The main goal of the HISC workshop, which was held at CWI in Amsterdam and had over fifty participants, was to investigate new paradigms to improve human interaction with symbolic computation software.
On simple and secure key distribution
Authors: Gene Tsudik, Els Van Herreweghen
Venue: Proceedings of the 1st ACM conference on Computer and communications security (1993)

The encrypted key exchange (EKE) protocol is augmented so that hosts do not store cleartext passwords. Consequently, adversaries who obtain the one-way encrypted password file may (i) successfully mimic (spoof) the host to the user, and (ii) mount dictionary attacks against the encrypted passwords, but cannot mimic the user to the host. Moreover, the important security properties of EKE are preserved&mdash;an active network attacker obtains insufficient information to mount dictionary attacks. Two ways to accomplish this are shown, one using digital signatures and one that relies on a family of commutative one-way functions.
Open issues and challenges in providing quality of service guarantees in high-speed networks
Authors: Jim Kurose
Venue: ACM SIGCOMM Computer Communication Review (1993)

In this paper we identify the challenges and open issues involved in providing quality-of-service (QOS) guarantees to sessions in a high-speed wide area network and briefly survey research in this area. Four approaches towards providing QOS guarantees are described and discussed: the tightly controlled approach, the approximate approach, the bounding approach, and the observation-based approach.
Node re-usability in structured hypertext systems
Authors: Omer Abdalla, Fazli Can
Venue: Proceedings of the 1993 ACM conference on Computer science (1993)

When the size of a graph-based hyperdocument exceeds a certain limit, the graph structure gets complicated and causes navigation and document management problems. A simple solution for this problem is the structuring of the hyperdocument into several smaller units. In this approach each unit contains nodes that share common properties and their link structures. Smaller, more manageable networks (called webs) which have their own, less complex graph structures are the result. In this paper we propose a model for hypertext systems which allows hyperdocument structuring using webs. The model demonstrates node reusability which becomes essential as it is very likely that the smaller units created will share nodes. The implementation details of a hypertext authoring system, HypAS, based on the proposed model are also provided.
Career paths in information systems: a longitudinal analysis
Authors: Jennifer L. Wagner, Harry C. Benham
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

Using data provided by the National Longitudinal Study of the High School Class of 1972, individual careers of 405 persons in information systems (IS) professions were studied for the 1972-1986 period. The focus of this research is on identifying factors which influence the tenure of IS professionals. It provides some descriptive statistics as well as a description of a suitable statistical model and its estimation. Analysis of IS tenure using a failure time model allows the adjustment for right censoring and determination of those factors which seem to influence tenure. Wage level, starting age, and field of study (college major) were found to be significantly related to the tenure of IS professionals.
Online partial deduction of logic programs
Authors: Steven Prestwich
Venue: Proceedings of the 1993 ACM SIGPLAN symposium on Partial evaluation and semantics-based program manipulation (1993)

Partial deduction systems must be guided by an unfolding strategy, telling them which atoms to unfold and when to stop unfolding. Online strategies exploit knowledge accumulated during the unfolding itself, for example in a goal stack, while offline strategies are fixed before unfolding begins. Online strategies are more powerful, but a major overhead for large programs is the analysis time spent on each atom, which increases as the knowledge grows. We describe an online strategy whose analysis time for each atom is independent of the amount of knowledge about that atom. This reduces transformation times for programs with large search spaces by an order of magnitude, while retaining the power of online analysis. Correctness, termination and nontriviality are shown.
Gap-definable counting classes
Authors: Stephen A. Fenner, Lance J. Fortnow, Stuart A. Kurtz
Venue: Journal of Computer and System Sciences (1994)

The function class #P lacks an important closure property: it is not closed under subtraction. To remedy this problem, we introduce the function class GapP as a natural alternative to #P. GapP is the closure of #P under subtraction and has all the other useful closure properties of #P as well. We show that most previously studied counting classes, including PP, C"=P, and Mod"kP, are ''gap-definable,'' i.e., definable using the values of GapP functions alone. We show that there is a smallest gap-definable class, SPP, which is still large enough to contain Few. We also show that SPP consists of exactly those languages low for GapP, and thus SPP languages are low for any gap-definable class. These results unify and improve earlier disparate results of J. Cai and L. Hemachandra (Math. Systems Theory23, No. 2 (1990), 95-106) and J. Kobler et al. (J. Comput. System Sci.44, No. 2 (1992), 272-286). We show further that any countable collection of languages is contained in a unique minimum gap-definable class, which implies that the gap-definable classes form a lattice under inclusion. Subtraction seems necessary for this result, since nothing similar is known for the #P-definable classes.
The design and implementation of CoBase
Authors: Wesley W. Chu, Matthew Merzbacher, Ladislav Berkovich
Venue: Proceedings of the 1993 ACM SIGMOD international conference on Management of data (1993)

CoBase, a cooperative database, is a new type of distributed database that integrates knowledge base technology with database systems to provide cooperative (approximate and conceptual) query answering. Based on the database schema and application characteristics, data are organized into conceptual (type abstraction) hierarchies. The higher levels of the hierarchy provide a more abstract data representation than the lower levels. Generalization (moving up in the hierarchy), specialization (moving down in the hierarchy) and association (moving between hierarchies) are the three key operations in deriving cooperative query answers. Relaxation in CoBase can also be specified explicitly in the query by the user or calling program through cooperative operators. We have extended SQL to CSQL by adding cooperative primitives. We describe the CoBase software implementation, including an inter-module data protocol that provides a uniform module interface. This modular approach provides flexibility in adding new relaxation modules and simplifies software maintenance. CoBase uses LOOM as its knowledge representation and inference system and supports relational data bases (e.g. Oracle and Sybase). We have demonstrated the feasibility and functionality of CoBase on top of a Transportation Database. The CoBase methodology has also been adopted in the multi-media medical distributed database project at UCLA, which provides approximate query answers to medical queries.
Operational semantics-directed compilers and machine architectures
Authors: John Hannan
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1994)

We consider the task of automatically constructing intermediate-level machine architectures and compilers generating code for these architectures, given operational semantics for source languages. We use operational semantics in the form of abstract machines given by rewrite systems in which the rewrite rules operate on terms representing states of computations. To construct compilers and new architectures we employ a particular strategy called pass separation, a form of staging transformation, that takes a program p and constructs a pair of programs p1, p2 such that p(x, y) = p2(p1(x), y)) for all x,y. If p represents an operational semantics for a language, with arguments x and y denoting a source program and its input data, then pass separation constructs programs p1 and p2 corresponding to a compiler and an executor. The compiler translates the source language into an intermediate-level target language, and the executor provides the definition for this language. Our use of pass separation supports the automatic definition of target languages or architectures, and the structure of these architectures is directed by the structure of the given source semantics. These architectures resemble abstract machine languages found in hand-crafted compilers. Our method is restricted to a limited class of abstract machines given as term-rewriting systems, but we argue that this class encompasses a large set of language definitions derived from more natural operational semantics. We provide two examples of our method by constructing compilers and target architectures for a simple functional language and a simple imperative language. Though we construct these architectures automatically, they bear a striking resemblance to existing architectures constructed by hand.
Original Contribution: Approximation of dynamical systems by continuous time recurrent neural networks
Authors: Ken-ichi Funahashi, Yuichi Nakamura
Venue: Neural Networks (1993)

In this paper, we prove that any finite time trajectory of a given n-dimensional dynamical system can be approximately realized by the internal state of the output units of a continuous time recurrent neural network with n output units, some hidden units, and an appropriate initial condition. The essential idea of the proof is to embed the n-dimensional dynamical system into a higher dimensional one which defines a recurrent neural network. As a corollary, we also show that any continuous curve can be approximated by the output of a recurrent neural network.
Issues in multimedia databases
Authors: H. V. Jagadish
Venue: Proceedings of the 1993 ACM SIGMOD international conference on Management of data (1993)

Multimedia is a popular term these days, and the database community, naturally, is talking about multimedia databases. The reason multimedia is getting so much attention is clear: technology trends are now beginning to make it possible to store and display, at a reasonable price, audio and still images through a computer. It is expected that video storage will also be affordable in the near future. The purpose of this panel is to explore what new challenges this multimedia explosion brings to the database community.
Generating Random Elements in SLn (Fq) by Random Transvections
Authors: Martin Hildebrand
Venue: Journal of Algebraic Combinatorics: An International Journal (1992)

This paper studies a random walk based on random transvections in SLn(Fq) and shows that, given &epsi; > 0, there is a constant c such that after n + c steps the walk is within a distance &epsi; from uniform and that after n &minus; c steps the walk is a distance at least 1 &minus; &epsi; from uniform. This paper uses results of Diaconis and Shahshahani to get the upper bound, uses results of Rudvalis to get the lower bound, and briefly considers some other random walks on SLn(Fq) to compare them with random transvections.
A three dimensional view and research agenda for the study of transfer of skills gained from formal end-user software training
Authors: Conrad Shayo, Lorne Olfman
Venue: Proceedings of the 1994 computer personnel research conference on Reinventing IS : managing information technology in changing organizations: managing information technology in changing organizations (1994)

Software training research indicates that some end-users do not subsequently transfer learned skills to their jobs. Yet, money, time and effort continue to be invested in formal software training. The three dimensional view presented in this article demonstrates that although the reasons for non-transfer are sometimes caused by trainee characteristics, software features, training approaches, the social context of work, and by the interaction between the four, training research generally focuses only on trainee characteristics and training approaches. We identify goal matching as a method that can ensure that trainees are getting what they need from the training process. Using goal matching and more directed training sessions should enhance the ability of software trainers to account for more transfer of learning to the work place.We propose a research program that can be used to explore the parameters of goal matching with respect to software training. We describe in detail a critical study in this program, and also discuss the need for replications such as an embedded multiple unit study that goes beyond the individual and includes the work group, department, or entire organization as the unit of analysis. We conclude that the replication of our proposed research design in different software training settings, organizations and work contexts hold a promise for improving software training design, and bringing a compatible solution to all the stakeholders of software training.
\ell_1-Rigid Graphs
Authors: M. Deza, M. Laurent
Venue: Journal of Algebraic Combinatorics: An International Journal (1994)

An \ell_1-graph is a graph whose nodes can be labeled by binary vectors in such a way that the Hamming distance between the binary addresses is, up to scale, the distance in the graph between the corresponding nodes. We show that many interesting graphs are \ell_1-rigid, i.e., that they admit an essentially unique such binary labeling.
Measure, Stochasticity, and the Density of Hard Languages
Authors: Jack H. Lutz, Elvira Mayordomo
Venue: SIAM Journal on Computing (1994)

The main theorem of this paper is that, for every real number $\alphaThus every $\leq^{P}_{n^{\alpha} - tt}$-hard language for E is exponentially dense. This strengthens Watanabe's 1987 result, that every $\leq^{P}_{(O \log n)-tt}$-hard language for E is exponentially dense. The combinatorial technique used here, the sequentially most frequent query selection, also gives a new, simpler proof of Watanabe's result. The main theorem also has implications for the structure of NP under strong hypotheses. Ogiwara and Watanabe (1991) have shown that the hypothesis $\p\ne\NP$ implies that every $\leq^{P}_{btt}$-hard language for NP is nonsparse (i.e., not polynomially sparse). Their technique does not appear to allow significant relaxation of either the query bound or the sparseness criterion. It is shown here that a stronger hypothesis---namely, that NP does not have measure 0 in exponential time---implies the stronger conclusion that, for every real $\alpha The proof of the main theorem uses a new, very general weak stochasticity theorem, ensuring that almost every language in E is statistically unpredictable by feasible deterministic algorithms, even with linear nonuniform advice.