ppxscal/embedding_network huggingface dataset:
Undefined Expressions and Logic in Z and B
Authors: Bill Stoddart, Steve Dunne, Andy Galloway
Venue: Formal Methods in System Design (1999)

In this paper we show how undefined expressions and undetermined predicates may arise when using the specification languages Z and B. We review how undefined terms have been handled in various formalisms (Principia Mathematica, Domain Theory, LPF,) and look at the effect of undefined expressions on the proof theory and the denotational meaning of specifications in Z and B. We note that in formal systems which make use of partial functions and have an unguarded equality axiom x &equals; x together with a classical two valued logic it is impossible to have a proof rules of the form y &equals; f(x) &rArr; x &map; y &isin; f and that consequently, assertions of the form y &equals; f(x) may have very little meaning.
GVT and scheduling in space time memory based techniques
Authors: Alessandro Fabbri
Venue: Proceedings of the thirteenth workshop on Parallel and distributed simulation (1999)

We present two GVT computation algorithms for PDES techniques with event based activities, and relying on a space-time memory abstraction. Algorithm 2 involves a modification in the activity control, and is based on an epoch coloring scheme. The effect of the modification is assessed through an experimental study on a simulator implemented in the Linda coordination language. Experiments are performed on a cluster of workstations, and show that the modified activity control discipline is able to enhance performances.
Two-Machine No-Wait Flow Shop Scheduling with Missing Operation
Authors: Celia A. Glass, J. N. D. Gupta, C. N. Potts
Venue: Mathematics of Operations Research (1999)

This paper considers the no-wait scheduling of n jobs in a two-machine flow shop, where some jobs require processing on the first machine only. The objective is to minimize the maximum completion time, or makespan. In view of its NP-hardness, we propose and analyze heuristic algorithms. Our main result is an O(n log n)-time heuristic which generates a schedule with makespan no more than 4/3 times that of an optimal schedule. This heuristic solves optimally the subproblem involving the jobs with no missing operations, using, for example, the well-known algorithm of Gilmore and Gomory, and then uses a list scheduling procedure to insert the remaining jobs in the schedule. A new proof technique is employed in the worst-case analysis, which has potential application in a variety of bin packing and scheduling problems.
Tolerating late memory traps in ILP processors
Authors: Xiaogang Qiu, Michel Dubois
Venue: ACM SIGARCH Computer Architecture News (1999)

ILP processors can execute a large number of instructions at the same time. Thus it becomes more and more difficult to support traps efficiently. On the other hand a current trend in architecture is to support various memory functions in software rather than hardware, usually by trapping the execution processor on a cache miss, TLB miss or a failed access to a local or remote memory. These late memory traps block the faulting instruction at the top of the active list, backing up the pipeline. Moreover the support for late memory traps may affect the performance of non-faulting memory instructions as well.In this paper we analyze the overhead caused by late memory traps in ILP processors and define several measures for this overhead. In order to tolerate late memory traps, we propose hardware prefetching of exception conditions and a tagged Store buffer to implement deferred traps on Stores. We show that, with these hardware optimizations, the overhead added by the lateness of traps is significantly reduced relative to the overhead of early traps. Because of caching effects the frequency of late memory traps usually decreases as they are taken deeper in the memory hierarchy and their overall impact on the execution time becomes negligible.
Navigation as multiscale pointing: extending Fitts' model to very high precision tasks
Authors: Yves Guiard, Michel Beaudouin-Lafon, Denis Mottet
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

Fitts pointing model has proven extremely useful for understanding basic selection in WIMP user interfaces. Yet todays interfaces involve more complex navigation within electronic environments. As navigation amounts to a form of multi-scale pointing, Fitts model can be applied to these more complex tasks. We report the results of a preliminary pointing experiment that shows that users can handle higher levels of task difficulty with two-scale rather than traditional one-scale pointing control. Also, in tasks with very high-precision hand movements, performance is higher with a stylus than with a mouse.
RIT's BS program in software engineering: a status report
Authors: Michael J. Lutz, J. Fernando Naveda
Venue: ACM SIGSOFT Software Engineering Notes (1999)

In the fall of 1996, the Rochester Institute of Technology (RIT) enrolled the first students in its undergraduate software engineering program. To the best of our knowledge, this was the first program in the U.S. leading to a Bachelor of Science in Software Engineering. This note is meant to apprise the readers of SEN of both the existence and current status of our program, and to contribute to the on-going conversation vis- agrave;-vis the proper education of professional software developers.
Recency-based TLB preloading
Authors: Ashley Saulsbury, Fredrik Dahlgren, Per Stenström
Venue: ACM SIGARCH Computer Architecture News (2000)

Caching and other latency tolerating techniques have been quite successful in maintaining high memory system performance for general purpose processors. However, TLB misses have become a serious bottleneck as working sets are growing beyond the capacity of TLBs. This work presents one of the first attempts to hide TLB miss latency by using preloading techniques. We present results for traditional next-page TLB miss preloading - an approach shown to cut some of the misses. However, a key contribution of this work is a novel TLB miss prediction algorithm based on the concept of &ldquo;recency&rdquo;, and we show that it can predict over 55% of the TLB misses for the five commercial applications considered.
A Comparison of Graphical Techniques for Asymmetric Decision Problems
Authors: Concha Bielza, Prakash P. Shenoy
Venue: Management Science (1999)

We compare four graphical techniques for representation and solution of asymmetric decision problems-decision trees, influence diagrams, valuation networks, and sequential decision diagrams. We solve a modified version of Covaliu and Oliver's Reactor problem using each of the four techniques. For each technique, we highlight the strengths, weaknesses, and some open issues that perhaps can be resolved with further research.
Tree fitting: an algebraic approach using profile distances
Authors: Richard Desper, Martin Vingron
Venue: Proceedings of the fourth annual international conference on Computational molecular biology (2000)

Distance methods play a central role in the field of phylogeny reconstruction, providing fast, efficient algorithms which yield reliable trees. The taxonomy problem is; given a set of DNA or amino acid sequences from several species, accurately reconstruct a phylogenetic tree representing their evolutionary history. Distance methods approach this problem by inferring a distance matrix of species-to-species evolutionary distances, and finding a tree which approximates the distance matrix. Our results consider the approach of using profile distances instead of leaf-to-leaf distances. We consider the vector space of tree metrics with regard to a basis generated by profile distances Given a fixed tree topology, we show how to project edge weights onto a topology based upon its set of profile distances. The projected edge weights provide topological insight, as negative edge weights will point to false edges in the topology. Although the presence of such negative edge weights is not guaranteed, we show that if the test tree is sufficiently close to the target tree in topology, negative edge weights will highlight the false edges. An algorithm is presented which uses this information to accurately reconstruct tree metrics.
A study on exception detection and handling using aspect-oriented programming
Authors: Martin Lippert, Cristina Videira Lopes
Venue: Proceedings of the 22nd international conference on Software engineering (2000)

Aspect-Oriented Programming (AOP) is intended to ease situations that involve many kinds of code tangling. This paper reports on a study to investigate AOP's ability to ease tangling related to exception detection and handling. We took an existing framework written in Java&trade;, the JWAM framework, and partially reengineered its exception detection and handling aspects using AspectJ&trade;, an aspect-oriented programming extension to Java.We found that AspectJ supported implementations that drastically reduced the portion of the code related to exception detection and handling. In one scenario, we were able to reduce that code by a factor of 4. We also found that, with respect to the original implementation in plain Java, AspectJ provided better support for different configurations of exceptional behaviors, more tolerance for changes in the specifications of exceptional behaviors, better support for incremental development, better reuse, automatic enforcement of contracts in applications that use the framework, and cleaner program texts. We also found some weaknesses of AspectJ that should be addressed in the future.
Merge replication in Microsoft's SQL server 7.0
Authors: Brad Hammond
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

SQL Server 7.0 offers three different styles of replication that we call Transactional Replication, Snapshot Replication, and Merge Replication. Merge Replication means that data changes can be performed at any replica, and that the changes performed at multiple replicas are later merged together. Because Merge Replication allows updates to disconnected replicas, it is particularly well suited to applications that require a lot of autonomy. A special process called the Merge Agent propagates changes between replicas, filters data as appropriate, and detects and handles conflicts according to user-specified rules.
Temporal deductive databases and infinite objects
Authors: Jan Chomicki, Tomasz Imieliński
Venue: Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1988)

We discuss deductive databases with one fixed occurrence of a monadic function symbol(successor) per predicate Databases of this kind can be used in a natural way to model simple patterns of events repeated in time, and this is why we term them temporal. Temporal deductive databases are also interesting from a theoretical point of view, because they give rise to infinite least fix-points and infinite query answers. We study complexity properties of finite query answers and define the notion of infinite objects which makes some infinite least fixpoints computable in finite time
A fully capable bidirectional debugger
Authors: Bob Boothe
Venue: ACM SIGSOFT Software Engineering Notes (2000)

The goal of this research project is to develop a bidirectional program debugger with which one can move as easily backwards as current debuggers move forward. We believe this will be a vastly more useful debugger. A programmer will be able to start at the manifestation of a bug and proceed backwards investigating how the program arrived at the incorrect state, rather than the current and often tedious practice of the user stepping and breakpointing monotonically forward and then being forced to start over from the beginning if they skip past a point of interest.Our experimental debugger has been implemented to work with C and C++ programs on Digital/Compaq Alpha based UNIX workstations.
Multicomponent Multidimensional Signals
Authors: Joseph P. Havlicek, David S. Harding, Alan C. Bovik
Venue: Multidimensional Systems and Signal Processing (1998)

In this brief paper, we extend the notion of multicomponent signal into multiple dimensions. A definition for multidimensional instantaneous bandwidth is presented and used to develop criteria for determining the multicomponent nature of a signal. We demonstrate application of the criteria by testing the validity of a multicomponent interpretation for a complicated nonstationary texture image.
A Realization Algorithm for SL2(R[x1, . . . ,xm]) over the Euclidean Domain
Authors: Hyungju Park
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

Let R be an arbitrary Euclidean domain and A be an n x n matrix of determinant 1 whose entries are elements of R. Gaussian elimination process based on Euclidean division algorithm (on R) allows one to write A as a product of elementary matrices over R. Suslin's stability theorem states that any n x n multivariate polynomial matrix of determinant 1 with $n\geq 3$ can be written as a product of elementary matrices. This result fails when n=2, and a counter-example was constructed by P. M. Cohn [ Inst. Hautes Études Sci. Publ. Math. 30 (1996), pp. 365--413]. In this paper, an algorithm is developed that determines precisely when a given matrix in SL2(R[x1, . . . ,xm]) allows a factorization into elementary matrices and, if it does, expresses it as a product of elementary matrices. This algorithm has potential applications to signal processing, in which case the coefficient ring R is usually taken as a field or a ring $\Bbb Z$ of integers. Extending the idea used in this algorithm, we disprove a conjecture of Tolhuizen--Hollmann--Kalker regarding the realizability of a certain FIR filter.
Of XML and databases (panel session): where's the beef?
Authors: Jennifer Widom, Adam Bosworth, Bruce Lindsay, Michael Stonebraker, Dan Suciu
Venue: ACM SIGMOD Record (2000)

This panel will examine the implications of the XML revolution, which is currently raging on the web, for database systems research and development.
On Efficiently Producing Quality Tests forCustom Circuits in PowerPC&trade; Microprocessors
Authors: Li-C. Wang, Magdy S. Abadir
Venue: Journal of Electronic Testing: Theory and Applications (2000)

Custom circuits, in contrast to those synthesized by automatic tools, are manually designed blocks of which the performance is critical to the full chip operation. Testing these blocks represents a major challenge and thus a crucial time-to-market factor in today's PowerPC microprocessor design environment. This paper investigates various methodologies for testing custom blocks. Issues of efficiently obtaining proper circuit models for ATPG tools as well as producing quality tests will be analyzed and discussed. Tradeoffs among various methods will be analyzed and compared. Experience and results based on recent PowerPC microprocessors will be reported.
Spectral Simulation of Supersonic Reactive Flows
Authors: Wai Sun Don, David Gottlieb
Venue: SIAM Journal on Numerical Analysis (1998)

We present in this paper numerical simulations of reactive flows interacting with shock waves. We argue that spectral methods are suitable for these problems and review the recent developments in spectral methods that have made them a powerful numerical tool appropriate for long-term integrations of complicated flows, even in the presence of shock waves. A spectral code is described in detail, and the theory that leads to each of its components is explained. Results of interactions of hydrogen jets with shock waves are presented and analyzed, and comparisons with ENO finite difference schemes are carried out.
Revisiting institution-wide e-mail: spamming our own
Authors: Jayne Ashworth
Venue: ACM SIGUCCS Newsletter (1998)

Issues involved with sending e-mail messages to every member of an institution of higher education vary from institution to institution, are many and have been discussed before. (See "Drowning in Our Success: Institution-wide Electronic Mail Messages," published in the SIGUCCS Newsletter, March/June 1997 issue.)
Basis of Eigenvectors and Principal Vectors Associated with Gauss--Seidel Matrix of A = tridiag [-1 2 -1]
Authors: L. Kohaupt
Venue: SIAM Review (1998)

For the $n \times n$ matrix $A = tri\!\diag \,[-1 \;2 -1]$, the associated Gauss--Seidel matrix $C$ is formed. The distinct nonzero eigenvalues of $C$ turn out to be $\lambda_j(C) = \cos^2 \frac{j}{n+1} \pi, \; j=1,2,\ldots,\left[\frac{n}{2}\right]$, and the pertinent eigenvectors are calculated. Moreover, the principal vectors up to the stage $\left[ \frac{n-1}{2} \right]$ pertinent to the eigenvalue $\lambda_0(C) = 0$ are determined. The set of eigenvectors and principal vectors forms a basis of ${\Bbb R}^n$.
Correction to RAMpage ASPOLOS paper
Authors: Phillip Machanick
Venue: ACM SIGARCH Computer Architecture News (1999)

This paper contains corrections to published results on the RAMpage memory hierarchy. The originally published results contained erroneous values for cache miss penalties for a conventional cache architecture against which the RAMpage hierarchy was being compared. The incorrect results showed that RAMpage with context switches on misses to DRAM had similar performance to a conventional 2-way associative L2 cache-based hierarchy. The corrected results show that the RAMpage hierarchy in fact outperforms a conventional 2-way associative cache hierarchy by up to 29%, for the measured variations.
Model-Checking with Coverability Graphs
Authors: Karsten Schmidt
Venue: Formal Methods in System Design (1999)

We show that several formulas of a temporal logic can be verified using the coverability graph of the underlying system. Of course, the procedure is not capable of verifying all formulae, since already the reachability problem for (unbounded) Petri nets is computationally hard. Thus, the procedure returns true, false, or unknown for a query. The formulae that can be verified cover most of the well known standard properties which have been listed in the context of coverability graph analysis so far.
APSARA: a tool to automate system design via intelligent pattern retrieval and synthesis
Authors: Sandeep Purao
Venue: ACM SIGMIS Database (1998)

Although a number of libraries of patterns have been developed for reuse, there is no mechanism for supporting automated design of object-oriented systems by the intelligent reuse of patterns from such libraries. We describe a web-based system, APSARA, the purpose of which is to create object-oriented designs based upon simple requirements descriptions. The system, developed in Java, implements a pattern retrieval and synthesis methodology that uses natural language processing and automated reasoning heuristics. The system is tested on multiple cases from different domains. The results are reported using metrics defined in the spirit of familiar measures such as recall, precision, coverage and spuriousness. These initial tests suggest that this is a feasible approach for the reuse of patterns in object-oriented design. The testing also reveals specific areas of concern and suggests a number of avenues for extending this research.
WASS: a security services for wireless ATM networks
Authors: D. Patiyoot, S. J. Shepherd
Venue: ACM SIGOPS Operating Systems Review (1999)

Recent years have witnessed the rapid growth in demanding for the use of wireless networks especially the one with can transmit all the service. Wireless ATM is the one that fulfil those requirements. This paper looks at the security issues in wireless ATM networks. It proposes the security services into user and control plane.
A simple packet aggregation technique for fault detection
Authors: Akira Kanamaru, Kohei Ohta, Nei Kato, Glenn Mansfield
Venue: International Journal of Network Management (2000)

Packet monitoring has become a standard technique in network management and when applied to a large-scale transit network yields a high volume of packets. To overcome this problem, we discuss the behavior of packets and present a symptom-based packet aggregation technique which is useful for fault detection. Copyright &copy; 2000 John Wiley Sons, Ltd.
Total Coloring With $\Delta + \mbox\lowercasepoly(\log \Delta)$ Colors
Authors: Hugh Hind, Michael Molloy, Bruce Reed
Venue: SIAM Journal on Computing (1999)

We provide a polynomial time algorithm which finds a total coloring of any graph with maximum degree $\D$, $\D$ sufficiently large, using at most $\D+8\log^8\D$ colors. This improves the best previous upper bound on the total chromatic number of $\D+18\D^{1/3}\log(3\D)$.
A collaborative fuzzy expert system for the Web
Authors: Tod A. Sedbrook
Venue: ACM SIGMIS Database (1998)

A convergence of Internet and fuzzy logic technologies provides an opportunity for experts and end users to collaborate in developing, refining, and testing knowledge-based systems. Internet technology removes geographical and time-based restraints, and fuzzy rule bases are easier to understand and maintain. This paper describes an architecture and a prototype for developing, delivering, and maintaining expert systems on the World Wide Web.The system's collaboration components allowed experts to monitor user consultations remotely, view summaries of responses, and trace-rule inference chains. Experts and users participated in real-time chat sessions or posted questions on extended discussion lists. The system allowed experts and users to experiment with real-time enhancements of knowledge bases. Fuzzy rules resulted in semantically richer knowledge bases that flexibly handled complex and uncertain knowledge. A fuzzy inference engine supported hedges and partial matching to assist users in applying knowledge and exploring Web-based data.
Multimedia virtual circuit model for MPEG on ATM networks
Authors: Anna Hać, Johnny On
Venue: International Journal of Network Management (1998)

A Multimedia Virtual Circuit &lpar;MVC&rpar; model for MPEG &lpar;Motion Picture Experts Group&rpar; transmission demonstrates an efficient method to accommodate the bandwidth requirements of multiple sources. In our simulation we compare the leaky bucket system that requires client to reserve the maximum rate and the proposed MVC system. &copy; 1998 John Wiley Sons, Ltd.
The wakeup problem in synchronous broadcast systems (extended abstract)
Authors: Leszek Gąsieniec, Andrzej Pelc, David Peleg
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

This paper studies the differences between two levels of synchronization in a distributed broadcast system (or a multiple access channel). In the globally synchronous model, all processors have access to a global clock. In the locally synchronous model, processors have local clocks ticking at the same rate, but each clock starts individually, when the processor wakes up. We consider the fundamental problem of waking up all of n processors of a completely connected broadcast system. Some processors wake up spontaneously, while others have to be woken up. Only wake processors can send messages; a sleeping processor is woken up upon hearing a message. The processors hear a message in a given round if and only if exactly one processor sends a message in that round. Our goal is to wake up all processors as fast as possible in the worst case, assuming an adversary controls which processors wake up and when. We analyze the problem in both the globally synchronous and locally synchronous models, with or without the assumption that n is known to the processors. We propose randomized and deterministic algorithms for the problem, as well as lower bounds in some of the cases. These bounds establish a gap between the globally synchronous and locally synchronous models.