ppxscal/embedding_network huggingface dataset:
A Router Architecture for Real-Time Communication in Multicomputer Networks
Authors: Jennifer Rexford, John Hall, Kang G. Shin
Venue: IEEE Transactions on Computers (1998)

Parallel machines have the potential to satisfy the large computational demands of real-time applications. These applications require a predictable communication network, where time-constrained traffic requires bounds on throughput and latency, while good average performance suffices for best-effort packets. This paper presents a new router architecture that tailors low-level routing, switching, arbitration, flow-control, and deadlock-avoidance policies to the conflicting demands of each traffic class. The router implements bandwidth regulation and deadline-based scheduling, with packet switching and table-driven multicast routing, to bound end-to-end delay and buffer requirements for time-constrained traffic while allowing best-effort traffic to capitalize on the low-latency routing and switching schemes common in modern parallel machines. To limit the cost of servicing time-constrained traffic, the router includes a novel packet scheduler that shares link-scheduling logic across the multiple output ports, while masking the effects of clock rollover on the represention of packet eligibility times and deadlines. Using the Verilog hardware description language and the Epoch silicon compiler, we demonstrate that the router design meets the performance goals of both traffic classes in a single-chip solution. Verilog simulation experiments on a detailed timing model of the chip show how the implementation and performance properties of the packet scheduler scale over a range of architectural parameters.
System support for object groups
Authors: Rachid Guerraoui, Pascal Felber, Benoît Garbinato, Karim Mazouni
Venue: ACM SIGPLAN Notices (1998)

This paper draws several observations from our experiences in building support for object groups. These observations actually go beyond our experiences and may apply to many other developments of object based distributed systems.Our first experience aimed at building support for Smalltalk object replication using the Isis process group toolkit. It was quite easy to achieve group transparency but we were confronted with a strong mismatch between the rigidity of the process group model and the flexible nature of object interactions. Consequently, we decided to build our own object oriented protocol framework, specifically dedicated to support object groups (instead of using a process group toolkit). We built our framework in such a way that basic distributed protocols, such as failure detection and multicasts, are considered as first class entities, directly accessible to the programmers. To achieve flexible and dynamic protocol composition, we had to go beyond inheritance and objectify distributed algorithms.Our second experience consisted in building a CORBA service aimed at managing group of objects written on different languages and running on different platforms. This experience revealed a mismatch between the asynchrony of group protocols and the synchrony of standard CORBA interaction mechanisms, which limited the portability of our CORBA object group service. We restricted the impact of this mismatch by encapsulating asynchrony issues inside a specific messaging sub-service.We dissect the cost of object group transparency in our various implementations, and we point out the recurrent sources of overheads, namely message indirection, marshaling/unmarshaling and strong consistency.
Hypertext versus Boolean access to biomedical information: a comparison of effectiveness, efficiency, and user preferences
Authors: Barbara M. Wildemuth, Charles P. Friedman, Stephen M. Downs
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (1998)

This study compared of two modes of access to a biomedical database, in terms of their effectiveness and efficiency in supporting clinical problem solving and in terms of user preferences. Boolean access, which allowed subjects to frame their queries as combinations of keywords, was compared to hypertext access, which allowed subjects to navigate from one database node to another. The accessible biomedical data were identical across system versions. Performance data were collected from two cohorts of first-year medical students, each student randomly assigned to either the Boolean or the hypertext system. Additional attitudinal data were collected from the second cohort. At each of two research sessions (one just before and one just after their bacteriology course), subjects worked eight clinical case problems, first using only their personal knowledge and, subsequently, with aid from the database. Database retrievals enabled students to answer questions they could not answer based on personal knowledge alone. This effect was greater when personal knowledge of bacteriology was lower. There were not statistically significant differences between the two forms of access, in terms of problem-solving effectiveness or efficiency. Students preferred Boolean access over hypertext access.
FastPep: a fast parasitic extraction program for complex three-dimensional geometries
Authors: Mattan Kamon, Nuno Marques, Jacob White
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

In this paper we describe a computationally efficient approach to generating reduced-order models from PEEC-based three-dimensional electromagnetic analysis programs. It is shown that a recycled multipole-accelerated approach applied to recent model order reduction techniques requires nearly two orders of magnitude fewer floating point operations than direct techniques thus allowing the analysis of larger, more complex three-dimensional geometries.
Scalable access within the context of digital libraries
Authors: X. Cheng, R. Dolin, M. Neary, S. Prabhakar, K. V. Ravi Kanth, D. Wu, D. Agrawal, A. El Abbadi, M. Freeston, A. Singh, T. Smith, J. Su
Venue: Proceedings of the IEEE international forum on Research and technology advances in digital libraries (1997)

This paper presents a summary of some of the work-in-progress within the Alexandria Digital Library Project. In particular, we present scalable methods of locating information at different levels within a distributed digital library environment. Starting at the high level, we show how queries can be routed to appropriate information sources. At a given source, efficient query processing is supported by using materialized views and multidimensional index structures. Finally, we propose solutions to the problem of storage and retrieval of large objects on secondary and tertiary storage.
Considerations in developing a formally-based visual programming language reference manual: a case study on the SLAM II language
Authors: Debbie K. Carter, Albert D. Baker
Venue: ACM SIGPLAN Notices (1997)

A language reference manual provides a definitive document containing complete and accurate details about the legality and meaning of the language's constructs. Some key decisions in writing a language reference manual are how to specify syntax, how to specify semantics, and how to structure the manual. Some of these components to a language reference manual have been active areas of research in the visual programming language community. The specific issue of how to put these together into a language reference manual has not been a strong part of this discussion. This paper reviews the recent research on specification methods and language presentation, and evaluates these methods for use within a visual programming language reference manual. The suggested specification that results from the evaluation is tested using SLAM II, a visually oriented queuing network simulation language which has enjoyed wide commercial use since its introduction in 1979.
Using Background Knowledge to Build Multistrategy Learners
Authors: Claude Sammut
Venue: Machine Learning (1997)

This paper discusses the role that background knowledge can play in building flexible multistrategy learning systems. We contend that a variety of learning strategies can be embodied in the background knowledge provided to a general purpose learning algorithm. To be effective, the general purpose algorithm must have a mechanism for learning new concept descriptions that can refer to knowledge provided by the user or learned during some other task. The method of knowledge representation is a central problem in designing such a system since it should be possible to specify background knowledge in such a way that the learner can apply its knowledge to new information.
A study of probability kinematics in information retrieval
Authors: F. Crestani, C. J. van Rijsbergen
Venue: ACM Transactions on Information Systems (TOIS) (1998)

We analyze the kinematics of probabilistic term weights at retrieval time for different Information Retrieval models. We present four models based on different notions of probabilistic retrieval. Two of these models are based on classical probability theory and can be considered as prototypes of models long in use in Information Retrieval, like the Vector Space Model and the Probabilistic Model. The two other models are based on a logical technique of evaluating the probability of a conditional called imaging; one is a generalization of the other. We analyze the transfer of probabilities occurring in the term space at retrieval time for these four models, compare their retrieval performance using classical test collections, and discuss the results. We believe that our results provide useful suggestions on how to improve existing probabilistic models of Information Retrieval by taking into consideration term-term similarity.
EigenTracking: Robust Matching and Tracking of Articulated Objects Using a View-Based Representation
Authors: Michael J. Black, Allan D. Jepson
Venue: International Journal of Computer Vision (1998)

This paper describes an approach for tracking rigid and articulated objects using a view-based representation. The approach builds on and extends work on eigenspace representations, robust estimation techniques, and parameterized optical flow estimation. First, we note that the least-squares image reconstruction of standard eigenspace techniques has a number of problems and we reformulate the reconstruction problem as one of robust estimation. Second we define a &ldquo;subspace constancy assumption&rdquo; that allows us to exploit techniques for parameterized optical flow estimation to simultaneously solve for the view of an object and the affine transformation between the eigenspace and the image. To account for large affine transformations between the eigenspace and the image we define a multi-scale eigenspace representation and a coarse-to-fine matching strategy. Finally, we use these techniques to track objects over long image sequences in which the objects simultaneously undergo both affine image motions and changes of view. In particular we use this &ldquo;EigenTracking&rdquo; technique to track and recognize the gestures of a moving hand.
Estimating Software Project Effort Using Analogies
Authors: Martin Shepperd, Chris Schofield
Venue: IEEE Transactions on Software Engineering (1997)

Accurate project effort prediction is an important goal for the software engineering community. To date most work has focused upon building algorithmic models of effort, for example COCOMO. These can be calibrated to local environments. We describe an alternative approach to estimation based upon the use of analogies. The underlying principle is to characterize projects in terms of features (for example, the number of interfaces, the development method or the size of the functional requirements document). Completed projects are stored and then the problem becomes one of finding the most similar projects to the one for which a prediction is required. Similarity is defined as Euclidean distance in n-dimensional space where n is the number of project features. Each dimension is standardized so all dimensions have equal weight. The known effort values of the nearest neighbors to the new project are then used as the basis for the prediction. The process is automated using a PC-based tool known as ANGEL. The method is validated on nine different industrial datasets (a total of 275 projects) and in all cases analogy outperforms algorithmic models based upon stepwise regression. From this work we argue that estimation by analogy is a viable technique that, at the very least, can be used by project managers to complement current estimation techniques.
Performance Models for the Processor Farm Paradigm
Authors: Alan S. Wagner, Halsur V. Sreekantaswamy, Samuel T. Chanson
Venue: IEEE Transactions on Parallel and Distributed Systems (1997)

In this paper, we describe the design, implementation, and modeling of a runtime kernel to support the processor farm paradigm on multicomputers. We present a general topology-independent framework for obtaining performance models to predict the performance of the start-up, steady-state, and wind-down phases of a processor farm. An algorithm is described, which for any interconnection network determines a tree-structured subnetwork that optimizes farm performance. The analysis technique is applied to the important case of k-ary tree topologies. The models are compared with the measured performance on a variety of topologies using both constant and varied task sizes.
The Complexity of Planar Counting Problems
Authors: Harry B. Hunt,  III, Madhav V. Marathe, Venkatesh Radhakrishnan, Richard E. Stearns
Venue: SIAM Journal on Computing (1998)

We prove the #P-hardness of the counting problems associated with various satisfiability, graph, and combinatorial problems, when restricted to planar instances. These problems include 3Sat, 1-3Sat, 1-Ex3Sat, Minimum Vertex Cover, Minimum Dominating Set, Minimum Feedback Vertex Set, X3C, Partition Into Triangles, and Clique Cover. We also prove the NP-completeness of the Ambiguous Satisfiability} problems [J. B. Saxe, Two Papers on Graph Embedding Problems, Tech. Report CMU-CS-80-102, Dept. of Computer Science, Carnegie Mellon Univ., Pittsburgh, PA, 1980] and the DP-completeness (with respect to random polynomial reducibility) of the unique satisfiability problems [L. G. Valiant and V. V. Vazirani, NP is as easy as detecting unique solutions, in Proc. 17th ACM Symp. on Theory of Computing, 1985, pp. 458--463] associated with several of the above problems, when restricted to planar instances. Previously, very few #P}-hardness results, no {\sf NP}-hardness results, and no DP-completeness results were known for counting problems, ambiguous satisfiability problems, and unique satisfiability problems, respectively, when restricted to planar instances.Assuming {\sf P \neq $ NP}, one corollary of the above results is that there are no $\epsilon$-approximation algorithms for the problems of maximizing or minimizing a linear objective function subject to a planar system of linear inequality constraints over the integers.
The impact of Ada and object-oriented design in NASA Goddard's Flight Dynamics Division
Authors: Sharon Waligora, John Bailey, Mike Stark
Venue: ACM SIGAda Ada Letters (1997)

This paper presents the highlights and key findings of 10 years of use and study of Ada and object-oriented design in NASA Goddard's Flight Dynamics Division (FDD). In 1985, the Software Engineering Laboratory (SEL) began investigating how the Ada language might apply to FDD software development projects. Although they began cautiously using Ada on only a few pilot projects, they expected that, if the Ada pilots showed promising results, the FDD would fully transition its entire development organization from FORTRAN to Ada within 10 years. However, 10 years later, the FDD still produced 80 percent of its software in FORTRAN and had begun using C and C++, despite positive results on Ada projects. This paper presents the final results of a SEL study to quantify the impact of Ada in the FDD, to determine why Ada has not flourished, and to recommend future directions regarding Ada. Project trends in both languages are examined as are external factors and cultural issues that affected the infusion of this technology. The detailed results of this study were published in a formal study report [1] in March of 1995. This paper supersedes the preliminary results of this study that were presented at the Eighteenth Annual Software Engineering Workshop in 1993 [2].
Support for Software Interrupts in Log-Based Rollback-Recovery
Authors: J. Hamilton Slye, E. N. Elnozahy
Venue: IEEE Transactions on Computers (1998)

The piecewise deterministic execution model is a fundamental assumption in many log-based rollback-recovery protocols. Process execution in this model consists of intervals, each starting with the receipt of a message at an application-defined execution point. Execution within each interval is deterministic and messages are the only source of nondeterminism that affects the computation. This simple model excludes the nondeterminism that results when asynchronous signals or interrupts occur at arbitrary execution points. As a result, a wide range of applications cannot use log-based rollback-recovery in practice.We present a solution that removes this restriction and allows applications to replay interrupts at the same execution points during recovery. The solution relies on using a software counter to compute the number of instructions between the asynchronous signals during normal operation. Should a failure occur, the instruction counts are used to force the replay of these signals at the same execution points. The execution of the application thus can be replayed to recreate the prefailure state while accommodating nondeterminism due to asynchronous signals. We then use the deterministic replay of interrupts to solve another problem, namely tracking nondeterminism due to interleaved shared memory access in multithreaded applications on a single processor. We use the instruction counter solution to implement a user-level thread package in which thread scheduling decisions can be replayed if a failure occurs. By repeating the scheduling decisions during an execution replay, threads access the shared memory in the same order and the execution to be reconstructed. This technique allows multithreaded applications to use log-based rollback-recovery with low overhead, which was not previously possible. We carried out two prototype implementations that have shown the overhead is no more than a 6 percent slowdown in application execution on the DEC Alpha, and from 6 percent to 18 percent on the Intel Pentium. Thus, restrictions of the piecewise deterministic execution model can be lifted at a reasonable cost.
Planar Functions and Planes of Lenz-Barlotti Class II
Authors: Robert S. Coulter, Rex W. Matthews
Venue: Designs, Codes and Cryptography (1997)

Planar functions were introduced by Dembowski and Ostrom [4] to describe projective planes possessing a collineation group with particular properties. Several classes of planar functions over a finite field are described, including a class whose associated affine planes are not translation planes or dual translation planes. This resolves in the negative a question posed in [4]. These planar functions define at least one such affine plane of order 3 ^e for every e &ge; 4 and their projective closures are of Lenz-Barlotti type II. All previously known planes of type II are obtained by derivation or lifting. At least when e is odd, the planes described here cannot be obtained in this manner.
Hierarchically-organized, multihop mobile wireless networks for quality-of-service support
Authors: Ram Ramanathan, Martha Steenstrup
Venue: Mobile Networks and Applications (1998)

MMWN is a modular system of adaptive link- and network-layer algorithms that provides a foundation on which to build mechanisms for quality-of-service provision in large, multihop mobile wireless networks. Such networks are a practical means for creating a communications infrastructure where none yet exists or where the previously existing infrastructure has been severely damaged. These networks provide communications for such diverse purposes as tactical maneuvering and strategic planning on the battlefield, emergency relief in an area afflicted by a natural disaster, and field studies conducted by a team of scientists in a remote location. In this paper, we describe three key components of the MMWN system: the clustering procedures for defining a virtual, hierarchical control structure superimposed on a large network of mobile switches and endpoints; the location management procedures for determining the current locations of mobile endpoints relative to the hierarchical control structure; and the virtual circuit management procedures for setting up and repairing virtual circuits as switches and endpoints move. We also provide simulation results that illustrate the robustness of each of these components with respect to a broad spectrum of transmission ranges and relative mobility of switches and endpoints.
V-Clip: fast and robust polyhedral collision detection
Authors: Brian Mirtich
Venue: ACM Transactions on Graphics (TOG) (1998)

This article presents the Voronoi-clip, or V-Clip, collision detection alogrithm for polyhedral objects specified by a boundary representation. V-Clip tracks the closest pair of features between convex polyhedra, using an approach reminiscent of the Lin-Canny closest features algorithm. V-Clip is an improvement over the latter in several respects. Coding complexity is reduced, and robustness is significantly improved; the implementation has no numerical tolerances and does not exhibit cycling problems. The algorithm also handles penetrating polyhedra, and can therefore be used to detect collisions between nonvconvex polyhedra described as hierarchies of convex pieces. The article presents the theoretical principles of V-Clip, and gives a pseudocode description of the algorithm. It also documents various test that compare V-Clip, Lin-Canny, and the Enhanced GJK algorithm, a simplex-based algorithm that is widely used for the same application. The results show V-Clip to be a strong contender in this field, comparing favorably with the other algorithms in most of the tests, in term of both performance and robustness.
The Correspondence Between Projective Codes and 2-weight Codes
Authors: A. E. Brouwer, M. Van Eupen
Venue: Designs, Codes and Cryptography (1997)

We show how to get a 1-1 correspondence between projective linear codes and 2-weight linear codes. A generalization of the construction gives rise to several new ternary linear codes of dimension six.
A Subclass of Binary Goppa Codes With Improved Estimationof the Code Dimension
Authors: Sergei V. Bezzateev, Natalia A. Shekhunova
Venue: Designs, Codes and Cryptography (1998)

A new bound for the dimension of binary Goppa codes belonging to a specific subclass is given. This bound improves the well-known lower bound for Goppa codes.
Call-cost directed register allocation
Authors: Guei-Yuan Lueh, Thomas Gross
Venue: Proceedings of the ACM SIGPLAN 1997 conference on Programming language design and implementation (1997)

Choosing the right kind of register for a live range plays a major role in eliminating the register-allocation overhead when the compiled function is frequently executed or function tails are on the most frequently executed paths. Picking the wrong kind of register for a live range incurs a high penalty that may dominate the total overhead of register allocation. In this paper, we present three improvements, storage-class analysis, benefit-driven simplification, and preference decision that are effective in selecting the right kind of register for a live range. Then we compare an enhanced Chaitin-style register allocator (with these three improvements) with priority-based and optimistic coloring.