ppxscal/embedding_network huggingface dataset:
tcc: a system for fast, flexible, and high-level dynamic code generation
Authors: Massimiliano Poletto, Dawson R. Engler, M. Frans Kaashoek
Venue: ACM SIGPLAN Notices (1997)

tcc is a compiler that provides efficient and high-level access to dynamic code generation. It implements the 'C ("Tick-C") programming language, an extension of ANSI C that supports dynamic code generation [15]. 'C gives power and flexibility in specifying dynamically generated code: whereas most other systems use annotations to denote run-time invariants. 'C allows the programmer to specify and compose arbitrary expressions and statements at run time. This degree of control is needed to efficiently implement some of the most important applications of dynamic code generation, such as "just in time" compilers [17] and efficient simulators [10, 48, 46].The paper focuses on the techniques that allow tcc to provide 'C's flexibility and expressiveness without sacrificing run-time code generation efficiency. These techniques include fast register allocation, efficient creation and composition of dynamic code specifications, and link-time analysis to reduce the size of dynamic code generators. tcc also implements two different dynamic code generation strategies, designed to address the tradeoff of dynamic compilation speed versus generated code quality. To characterize the effects of dynamic compilation, we present performance measurements for eleven programs compiled using tcc. On these applications, we measured performance improvements of up to one order of magnitude.To encourage further experimentation and use of dynamic code generation, we are making the tcc compiler available in the public domain. This is, to our knowledge, the first high-level dynamic compilation system to be made available.
Real-Time Schedulability Tests for Preemptive Multitasking
Authors: C. J. Fidge
Venue: Selected papers from the 4th workshop on Parallel and distributed real-time systems (1998)

When developing multitasking real-time systems, schedulability tests are used to formally prove that a given task set will meet its deadlines. A wide range of such tests have appeared in the literature. This tutorial acts as a guide to the major tests available for preemptive multitasking applications.
Evaluating uniform expressions within two steps of minimum parallel time
Authors: Robert A. Wagner
Venue: Journal of the ACM (JACM) (1997)

Consider an array of Processing Elements [PEs], connected by a 2-dimensional grid network, and holding at most one operand of an expression in each PE. Suppose that each PE is allowed, in any one parallel step, to receive one item of data from any of its four immediate neighbors, and to transmit one datum, as well. How can an associative operator, such as addition, combine all the operands, using as little time for communciation as possible? An expression using such a single operator is termed a uniform expression. When the total number of communication links used is the measure of goodness, this problem becomes a Steiner Tree problem, in the Manhattan Distance metric. When the measure is minimizing the parallel time to completion, a method for solving this problem is given which is optimal to within an additive constant of two time-steps. The method has applications when the operands are matrices, spread over an array of PEs, as well. Some lower bounds for this problem, in more general networks, are also proven.
Dynamic Data Reallocation for Skew Management inShared-Nothing Parallel Databases
Authors: Abdelsalam (Sumi) Helal, David Yuan, Hesham El-Rewini
Venue: Distributed and Parallel Databases (1997)

The shared nothing parallel database architecture is gaining wide popularity due to its scalability and increased data availability. However, in order to efficiently utilize parallelism in such architecture, independent data sets must be assigned to different processing nodes. This, of course, can initially be achieved by employing a careful partitioning scheme that allocates disjoint data sets to different processors. However, variations in the data access pattern may render some processors overloaded while others underloaded. This skewness in data access decreases the effective parallelism and eventually leads to overall performance degradation. A number of solutions have been proposed to periodically perform data re-allocation to remove the skewness in data access. Most of the proposed solutions perform either static re-allocation that requires the system to be taken off-line or dynamic, but non-transactional, re-allocation. In this paper, we introduce a dynamic and transactional re-allocation scheme based on the work on disk cooling in shared memory architecture by Scheuermann et al. The proposed scheme enhances the effective parallelism in the system regardless of the variations in the pattern of access. The proposed scheme detects access skew as it occurs and re-allocates data partitions to underloaded processing elements on the fly. Only the block being moved becomes unavailable. In addition, mutual consistency among transactions concurrent to the re-allocation event is preserved. The proposed scheme also uses replication as an additional cooling mechanism to help distribute access load over multiple replicas. We conducted a series of simulation experiments to study the behavior of shared nothing parallel database systems with and without the proposed dynamic re-allocation scheme. We also experimented with several replication strategies to measure their impact on the system performance. Finally, we studied the effect of using different concurrency control strategies on the efficiency of dynamic re-allocation.
Fault Tolerance Measures for m-Ary n-Dimensional Hypercubes Based on Forbidden Faulty Sets
Authors: Jie Wu, Guanghui Guo
Venue: IEEE Transactions on Computers (1998)

In this paper, we study fault tolerance measures for m-ary n-dimensional hypercubes based on the concept of forbidden faulty sets. In a forbidden faulty set, certain nodes cannot be faulty at the same time and this model can better reflect fault patterns in a real system than the existing ones. Specifically, we study the bounds of the minimum vertex cut set for m-ary n-dimensional hypercubes by requiring each node to have at least k healthy neighbors. Our result enhances and generalizes a result by Latifi et al. for binary hypercubes. Our study also shows that the corresponding result based on the traditional fault model (where k is zero) tends to underestimate network resilience of large networks such as m-ary n-dimensional hypercubes.
APL teaching bugs
Authors: Howard A. Peelle, Murray Eisenberg
Venue: ACM SIGAPL APL Quote Quad (1985)

This paper discusses &ldquo;APL teaching bugs&rdquo;, in three senses: (1) issues inherent in the teaching of APL that confront the instructor with difficult choices; (2) potential mistakes sometimes made by instructors teaching APL; and (3) problematic aspects of the design of APL that are especially difficult to explain. These teaching bugs are presented as provocative questions, but the &ldquo;answers&rdquo; are left to individual instructors. By facing these questions, teachers may make APL more comprehensible and hence foster its acceptance and growth.
Caps and Colouring Steiner Triple Systems
Authors: Aiden Bruen, Lucien Haddad, David Wehlau
Venue: Designs, Codes and Cryptography (1998)

Hill [6] showed that the largest cap in PG(5,3) has cardinality 56. Using this cap it is easy to construct a cap of cardinality 45 in AG(5,3). Here we show that the size of a cap in AG(5,3) is bounded above by 48. We also give an example of three disjoint 45-caps in AG(5,3). Using these two results we are able to prove that the Steiner triple system AG(5,3) is 6-chromatic, and so we exhibit the first specific example of a 6-chromatic Steiner triple system.
Self-Testing Embedded Two-Rail Checkers
Authors: Dimitris Nikolos
Venue: Journal of Electronic Testing: Theory and Applications (1998)

This paper presents a new simple and straightforward method for designing Completely Testable Embedded (CTE) parity trees, and Self-Testing Embedded (STE) two-rail checkers. In the design of CTE parity trees the two inputs XOR gate has been used as the building block. In the case of STE two-rail checkers with n input pairs the building block is the two-rail checker with 2 input pairs. During normal, fault free, operation each XOR gate receives all possible input vectors, while each two-rail checker with 2 input pairs receives all possible code input vectors. The great advantage of the proposed method is that it is the only one that gives in a simple and straightforward way an optimal CTE/STE tree realization with respect to the hardware (number of blocks) and the speed (number of block levels). Designing the two input two-rail checker as proposed by Lo in IEEE J. of Solid-State Circuits, 1993, we get optimal STE two-rail checkers taking into account realistic faults.
Experiences with selecting search engines using metasearch
Authors: Daniel Dreilinger, Adele E. Howe
Venue: ACM Transactions on Information Systems (TOIS) (1997)

Search engines are among the most useful and high-profile resources on the Internet. The problem of finding information on the Internet has been replaced with the problem of knowing where search engines are, what they are designed to retrieve, and how to use them. This article describes and evaluates SavvySearch, a metasearch engine designed to intelligently select and interface with multiple remote search engines. The primary metasearch issue examined is the importance of carefully selecting and ranking remote search engines for user queries. We studied the efficacy of SavvySearch's incrementally acquired metaindex approach to selecting search engines by analyzing the effect of time and experience on performance. We also compared the metaindex approach to the simpler categorical approach and showed how much experience is required to surpass the simple scheme.
The k-Steiner Ratio in Graphs
Authors: Al Borchers, Ding-Zhu Du
Venue: SIAM Journal on Computing (1997)

A Steiner minimum tree (SMT) is the shortest-length tree in a metric space interconnecting a set of points, called the regular points, possibly using additional vertices. A k-size Steiner minimum tree (kSMT) is one that can be split into components where all regular points are leaves and all components have at most k leaves. The k-Steiner ratio, $\rho_{k}$, is the infimum of the ratios SMT/kSMT over all finite sets of regular points in all possible metric spaces, where the distances are given by a complete graph. Previously, only $\rho_{2}$ and $\rho_{3}$ were known exactly in graphs, and some bounds were known for other values of k. In this paper, we determine $\rho_{k}$ exactly for all k. From this we prove a better approximation ratio for the Steiner tree problem in graphs.
RISCE&mdash;a reduced instruction set circuit extractor for hierarchical VLSI layout verification
Authors: Volker Henkel, Ulrich Golze
Venue: Proceedings of the 25th ACM/IEEE Design Automation Conference (1988)

We present a circuit extractor preserving the hierarchical layout structure isomorphically. As opposed to existing extractors, our approach permits all cell overlaps which are electrically meaningful. New mask operations based on stretched geometries handle topologically open and closed areas. A reduced set of model independent instructions is introduced for device recognition. An existing implementation is discussed.
Recursion and grammars for CS2
Authors: Viera K. Proulx
Venue: Proceedings of the 2nd conference on Integrating technology into computer science education (1997)

A programming exercise on recursion in which students create drawings of simple and bracketed Lindenmayer Systems provides a context for exploring additional computer science concepts. The resulting drawings give students a better understanding of the power of recursion as well as the rate of growth of time complexity with multiple successive recursive calls. We describe the exercise, the concepts that need to be addressed to solve the problems, and the results of using this exercise in our classes.
Unsteady Two-Dimensional Flows in Complex Geometries: Comparative Bifurcation Studies with Global Eigenfunction Expansions
Authors: Anil K. Bangia, Paul F. Batcho, Ioannis G. Kevrekidis, George Em. Karniadakis
Venue: SIAM Journal on Scientific Computing (1997)

We present a bifurcation study of the incompressible Navier--Stokes equations in a model complex geometry: a spatially periodic array of cylinders in a channel. The dynamics of the flow include a Hopf bifurcation from steady to oscillatory flow at an approximate Reynolds number R of 350 and the appearance of a second frequency at approximately $R\simeq 890$. The multiple frequency dynamics include a substantial increase in spatial and temporal scales with Reynolds number as compared with the simple limit cycle oscillation present close to R = 350. Numerical bifurcation studies of the dynamics are performed using three forms of global eigenfunction expansions. The first basis set is derived through principal factor analysis (Karhunen--Loève expansion) of snapshots from accurate direct spectral element numerical solutions of the Navier--Stokes equations. The second set is obtained from the eigenfunctions of the Stokes operator for this geometry. Finally eigenfunctions are derived from a singular Stokes operator, i.e., the Stokes operator modified to include a variable coefficient which vanishes at the domain boundaries. Truncated systems of ($\sim 100$) ODEs are obtained through projection of the Navier--Stokes equations onto the basis sets, and a comparative study of the resulting dynamical models is performed.
An extensible probe architecture for network protocol performance measurement
Authors: G. Robert Malan, Farnam Jahanian
Venue: ACM SIGCOMM Computer Communication Review (1998)

This paper describes the architecture and implementation of Windmill, a passive network protocol performance measurement tool. Windmill enables experimenters to measure a broad range of protocol performance metrics by both reconstructing application-level network protocols and exposing the underlying protocol layers' events. Windmill is split into three functional components: a dynamically compiled Windmill Protocol Filter (WPF), a set of abstract protocol modules, and an extensible experiment engine. To demonstrate Windmill's utility, the results from several experiments are presented. The first set of experiments suggests a possible cause for the correlation between Internet routing instability and network utilization. The second set of experiments highlights: Windmill's ability to act as a driver for a complementary active Internet measurement apparatus, its ability to perform online data reduction, and the non-intrusive measurement of a closed system.
From manufacturing document requirements to customized authoring and automated publishing framework
Authors: Marc Le Bissonnais, Francois Prunet
Venue: ACM SIGSOFT Software Engineering Notes (1997)

The aim of this paper is a working-out of an open authoring framework for an automated documentation process binded with an object manufacturing-specific engineering framework. Using standards close together to support product documentation as part of the life-cycle of manufactured products is becoming an actual and urgent topic for industry. Indeed, this area leads people to describe very complex systems, but it uses different models, based on many standards, to be handled together during the life cycle steps of these systems. A customizable automated authoring and publishing framework trying to take into account some multimedia research aspects should make the work easier for the designers of such manufacturing systems, allowing them to follow the design process and to have a better communication. We contribute to the problem by using an object-oriented approach providing structuration, abstraction, re-use and easier upgrading based upon textual and graphical modes through the integration and merging of domain models with object services like customized editors, browsers and parsers.
Graphical information resources: maps and beyond
Authors: Michael Lesk
Venue: Proceedings of the 8th annual international ACM SIGIR conference on Research and development in information retrieval (1985)

The rise of computer graphics offers a new challenge for information retrieval: how to search and retrieve information which is partly or wholly graphical. As an example, procedures for handling geographical information, such as street maps and directories are explained. With this data, it is possible to find routes on maps, retrieve locations and names of people or businesses, and draw maps. But a comparison of these programs with programs for face processing or computer typesetting makes clear how far we are from general purpose routines. Today successful graphics routines contain a great deal of local domain knowledge. There is no analog of the simple keyword systems that handle textual documents in any subject area. Just as computational linguists have found that subject matter expertise is necessary to do really sophisticated processing of English, it seems also necessary to sophisticated processing of pictures; the difference is that we don't know how to do unsophisticated processing of graphics.
Chirality
Authors: Richard I. Hartley
Venue: International Journal of Computer Vision (1998)

It is known that a set of points in three-dimensions is determined up to projectivity from two views with uncalibrated cameras. It is shown in this paper that this result may be improved by distinguishing between points in front of and behind the camera. Any point that lies in an image must lie in front of the camera producing that image. Using this idea, it is shown that the scene is determined from two views up to a more restricted class of mappings known as quasi-affine transformations, which are precisely those projectivities that preserve the convex hull of an object of interest. An invariant of quasi-affine transformation known as the chiral sequence of a set of points is defined and it is shown how the chiral sequence may be computed using two uncalibrated views. As demonstrated theoretically and by experiment the chiral sequence may distinguish between sets of points that are projectively equivalent. These results lead to necessary and sufficient conditions for a set of corresponding pixels in two images to be realizable as the images of a set of points in three dimensions.Using similar methods, a necessary and sufficient condition is given for the orientation of a set of points to be determined by two views. If the perspective centres are not separated from the point set by a plane, then the orientation of the set of points is determined from two views.
A Low-Voltage Fully Differential Constant-Gm Rail-to-Rail CMOS Operational Amplifier
Authors: Giuseppe Ferri, Willy Sansen, Vincenzo Peluso
Venue: Analog Integrated Circuits and Signal Processing (1998)

A low-voltage fully differential CMOS operational amplifier with constant-g_m and rail-to-rail input and output stages is presented. It is the fully differential version of a previously realized single-ended operational amplifier where a novel circuit to ensure constant transconductance has been implemented [1]. The input stage is a rail-to-rail structure formed by two symmetrical OTAs in parallel (the input transistors are operating in weak inversion). The class-AB output stages have also a full voltage swing. A rail-to-rail input common mode feedback structure allows the output voltage control. Measurements in a 0.7 &micro; standard CMOS process with threshold voltages of about 0.7 V have been done. The minimum experimental supply voltage is about 1.1 V. The circuit provides a 60 dB low frequency voltage gain and about 1.5 MHz unity gain frequency for a total power consumption of about 0.72 mW at a 1.5 V supply voltage.
Design automation for the component parts industry
Authors: Sheldon S. L. Chang
Venue: Proceedings of the 25th ACM/IEEE Design Automation Conference (1988)

Design automation in the component parts industry from purchase inquiry to finished product delivery is described. The computerized process simulates human decision makers, eliminates bottlenecks, and frees human decision makers from doing routine work. Fuzzy set analysis appears to be a natural method to be used in the early stages of a design process. Its language describes well the imprecise or blurred specifications at the initial phase of an engineering design (Ref. (1), (3), (4), (5)). The mathematics of fuzzy-set analysis leads naturally to a process which can be identified with heuristic selection (Ref. (2)). They are alternative means for realizing the product selection and design specification program (PSDS) in the computerized process.
Transitory Image Sequences, Asymptotic Properties, and Estimation of Motion and Structure
Authors: John Weng, Yuntao Cui, Narendra Ahuja
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

A transitory image sequence is one in which no scene element is visible through the entire sequence. When a camera system scans a scene which cannot be covered by a single view, the image sequence is transitory. This article deals with some major theoretical and algorithmic issues associated with the task of estimating structure and motion from transitory image sequences. It is shown that integration with a transitory sequence has properties that are very different from those with a non-transitory one. Two representations, world-centered (WC) and camera-centered (CC), behave very differently with a transitory sequence. The asymptotic error rates derived in this article indicate that one representation is significantly superior to the other, depending on whether one needs camera-centered or world-centered estimates. To establish the tightness of these error rates, it has been shown that these reachable error rates are in fact the lowest possible given by a theoretical lower error bound, the Cramér-Rao error bound. Based on these results, we introduce an efficient "cross-frame" estimation technique for the CC representation. For the WC representation, our analysis indicates that a good technique should be based on camera global pose instead of interframe motions. In addition to testing with synthetic data, rigorous experiments were conducted with real-image sequences taken by a fully calibrated camera system. The comparison of the experimental results with the ground truth has demonstrated that a good accuracy can be obtained from transitory image sequences.