ppxscal/embedding_network huggingface dataset:
Supporting multiple view maintenance policies
Authors: Latha S. Colby, Akira Kawaguchi, Daniel F. Lieuwen, Inderpal Singh Mumick, Kenneth A. Ross
Venue: ACM SIGMOD Record (1997)

Materialized views and view maintenance are becoming increasingly important in practice. In order to satisfy different data currency and performance requirements, a number of view maintenance policies have been proposed. Immediate maintenance involves a potential refresh of the view after every update to the deriving tables. When staleness of views can be tolerated, a view may be refreshed periodically or (on-demand) when it is queried. The maintenance policies that are chosen for views have implications on the validity of the results of queries and affect the performance of queries and updates. In this paper, we investigate a number of issues related to supporting multiple views with different maintenance policies. We develop formal notions of consistency for views with different maintenance policies. We then introduce a model based on view groupings for view maintenance policy assignment, and provide algorithms, based on the viewgroup model, that allow consistency of views to be guaranteed. Next, we conduct a detailed study of the performance aspects of view maintenance policies based on an actual implementation of our model. The performance study investigates the trade-offs between different maintenance policy assignments. Our analysis of both the consistency and performance aspects of various view maintenance policies are important in making correct maintenance policy assignments.
Tight Bounds on the Information Rate of Secret SharingSchemes
Authors: Carlo Blundo, Alfredo De Santis, Roberto De Simone, Ugo Vaccaro
Venue: Designs, Codes and Cryptography (1997)

A secret sharing scheme is a protocol by means of which a dealer distributes a secret s among a set of participants P in such a way that only qualified subsets of P can reconstruct the value of s whereas any other subset of P, non-qualified to know s, cannot determine anything about the value of the secret. In this paper we provide a general technique to prove upper bounds on the information rate of secret sharing schemes. The information rate is the ratio between the size of the secret and the size of the largest share given to any participant. Most of the recent upper bounds on the information rate obtained in the literature can be seen as corollaries of our result. Moreover, we prove that for any integer d there exists a d-regular graph for which any secret sharing scheme has information rate upper bounded by 2/(d+1). This improves on van Dijk&lsquo;s result dik and matches the corresponding lower bound proved by Stinson in [22].
A high-level microprogrammed processor
Authors: Christian Iseli, Eduardo Sanchez
Venue: Proceedings of the 23rd annual workshop and symposium on Microprogramming and microarchitecture (1990)

This paper presents a microprogrammable processor, intended for small real-time applications, and the development system associated with it. The processor, designed for an optimal execution of a structured high-level language, has only one level of language: a microcode allowing the execution of three operations in parallel. The possible parallelisms are detected by the compiler, which generates microcode directly. Two other tools are presented: an interactive microassembler and an interactive, window and mouse-driven, simulator. The integrated circuit for a first application is being carried out.
Infomaster: an information integration system
Authors: Michael R. Genesereth, Arthur M. Keller, Oliver M. Duschka
Venue: ACM SIGMOD Record (1997)

Infomaster is an information integration system that provides integrated access to multiple distributed heterogeneous information sources on the Internet, thus giving the illusion of a centralized, homogeneous information system. We say that Infomaster creates a virtual data warehouse. The core of Infomaster is a facilitator that dynamically determines an efficient way to answer the user's query using as few sources as necessary and harmonizes the heterogeneities among these sources. Infomaster handles both structural and content translation to resolve differences between multiple data sources and the multiple applications for the collected data. Infomaster connects to a variety of databases using wrappers, such as for Z39.50, SQL databases through ODBC, EDI transactions, and other World Wide Web (WWW) sources. There are several WWW user interfaces to Infomaster, including forms based and textual. Infomaster also includes a programmatic interface and it can download results in structured form onto a client computer. Infomaster has been in production use for integrating rental housing advertisements from several newspapers (since fall 1995), and for meeting room scheduling (since winter 1996). Infomaster is also being used to integrate heterogeneous electronic product catalogs.
The bisector surface of rational space curves
Authors: Gershon Elber, Myung-So Kim
Venue: ACM Transactions on Graphics (TOG) (1998)

Given a point and a rational curve in the plane, their bisector curve is rational [Farouki and Johnston 1994a]. However, in general, the bisector of two rational curves in the plane is not rational [Farouki and Johnstone 1994b]. Given a point and a rational space curve, this art icle shows that the bisector surface is a rational ruled surface. Moreover, given two rational space curves, we show that the bisector surface is rational (except for the degenerate case in which the two curves are coplanar).
Imaging of the orifice of the left ventricular outflow tract: technique and initial results
Authors: Takeshi Komoda, Roland Hetzer, Johann Oellinger, Henryk Siniawski, Joseph Hofmeister, Michael Hübler, Roland Felix, Chikao Uyama, Hajime Maeta
Venue: Technology and Health Care (1997)

The mechanism of left ventricular outflow tract (LVOT) obstruction in the patient after mitral valve replacement or repair was examined with the aid of 2D echocardiography. For the interpretation of the spatial relationship between the aortic root and mitral annulus, however, the 2D display is sometimes inadequate since it may not simultaneously capture these structures in each center. We developed a method to clarify this relationship in 3D based on magnetic resonance images. We defined the office of the left ventricular outflow tract (LVOT orifice), consisting of, in turn, a muscular region, i.e., edge of the interventricular septum, and an annular region, i.e., the annulus of the anterior mitral leaflet. In this paper we present image data obtained from one of eight normal subjects examined and compare this with data of one of two patients who preoperatively suffered degenerative mitral regurgitation and subsequently underwent chordal-preserving mitral valve replacement, in which anterior chordae were reattached to the anterior annulus. In the normal subject, the mitral annulus exhibited a flexible change in shape during the systole, maintaining sufficient LVOT orifice size. In the patient, the prosthetic valve exhibited translational motion during systole, resulting in dynamic LVOT obstruction. This phenomenon was also observed in one other case. Furthermore, the lateral view of the LVOT orifice revealed a projection of the prosthetic valve into the LVOT, causing mechanical LVOT obstruction. The finding that translational motion of the prosthetic valve with an inflexible mitral annulus results in dynamic LVOT obstruction may support the hypothesis that annular rigidity causes dynamic LVOT obstruction after mitral valve repair with a rigid prosthetic ring.
Simulation of an injector plunger production line
Authors: Hank Grant, Maged Dessouky, Dan Gauthier
Venue: Proceedings of the 17th conference on Winter simulation (1985)

As part of the design of a new production system, simulation was used to evaluate four production cell design options for the manufacturer of fuel injector plungers. By simulating the proposed design options, Rochester Products was able to select the alternative that would provide the best performance. This paper describes the model used and provides details on the analysis performed.
On the Optimality of the Median Cut Spectral Bisection Graph Partitioning Method
Authors: Tony F. Chan, P. Ciarlet,  Jr., W. K. Szeto
Venue: SIAM Journal on Scientific Computing (1997)

Recursive spectral bisection (RSB) is a heuristic technique for finding a minimum cut graph bisection. To use this method the second eigenvector of the Laplacian of the graph is computed and from it a bisection is obtained. The most common method is to use the median of the components of the second eigenvector to induce a bisection. We prove here that this median cut method is optimal in the sense that the partition vector induced by it is the closest partition vector, in any ls norm, for $s\ge1$, to the second eigenvector. Moreover, we prove that the same result also holds for any m-partition, that is, a partition into m and (n-m)$ vertices, when using the mth largest or smallest components of the second eigenvector.
A very fast algorithm for RAM compression
Authors: Luigi Rizzo
Venue: ACM SIGOPS Operating Systems Review (1997)

Compressed virtual memory systems have been suggested, and in some cases implemented, to improve the effectiveness of use of physical RAM. However, most proposals and/or implementations are based on adaptive compression algorithms which achieve good compression ratios, but are slow compared to a local disk. Hence, they can only give some advantage with very slow (e.g. network-mounted) swap devices. In this paper we show that in many cases memory pages contain highly compressible data, with a very large amount of zero-valued elements. This suggests the replacement of slow, adaptive compression algorithms with very fast ones based on static Huffman codes.We present one such algorithm which, paired with a careful layout of the data, is able to compress 4KB pages at 40MB/s even when implemented in software on an inexpensive Pentium 100 system. We also show that the algorithm can achieve interesting compression ratios despite its simplicity.Since the compression/decompression speed of our algorithms exceeds disk bandwidth, its use in a compressed VM system can lead to both memory savings and speed improvements in servicing page faults. In this paper we discuss some possible applications of the algorithm in a compressed VM system.
Reasoning About Data Provided By Federated Deductive Databases
Authors: Laurence Cholvy
Venue: Journal of Intelligent Information Systems (1998)

This paper focuses on the problem of reasoning with information provided by a group of databases which share a common set of rules (deductive rules, integrity constraints). Each database is assumed to be consistent with the rules, but federating them may lead to contradictions.This paper describes a logic of beliefs, based on KD logic, for reasoning with contradictory information provided by several databases. It also presents a theorem prover, associated with this logic. This prover, described as a meta-interpreter of PROLOG allows us to derive formulas of the form: given the databases and the rules, assuming an order of relative reliability between the databases, is a given formula deducible? or, what are the individuals which satisfy a given formula? When the set of rules is not recursive, we prove the correctness of this theorem-prover.
A real-time Ada design method based on DoD-STD-2167A
Authors: Christophe Ville, Alain Bratel
Venue: Proceedings of the conference on TRI-ADA '90 (1990)

This paper presents the THOMSON CSF design methodology used on large Real-Time Ada projects compliant with the DOD-STD-2167A standard. This design methodology was defined within the context of the RMR radar software project. RMR software is still under development and will be integrated in the Navy, Airfield and Battlefield radar systems over the next decade. The challenge was to conceive a methodology compliant with the DOD-STD-2167A standard, mapped to Ada features, that would guide the design activity and optimize the use of available design tools, saving time for designers and money for the company. This paper explains our specific design choices and describes their implementation in the RMR project. It also introduces the design tools used during the design process.
Modeling and analysis of aircraft offloading operations
Authors: S. Manivannan, Michael E. Zeimer
Venue: Proceedings of the 28th conference on Winter simulation (1996)

This paper describes a successful application of discrete event simulation techniques to evaluate and improve the plane offloading operations in a central aircargo Hub. The simulation model was built after a thorough analysis of plane offloading procedures, freight flow, and work rules involving the usage of equipment and personnel. Experimentation and extensive statistical analysis were performed to determine the (i) best operating rules, (ii) strategic changes to tug and dolly operations, and (iii) ramp configuration. The final recommendations based on a rigorous analysis to improve the ramp performance and use of models in planning and control are discussed.
A performance evaluation of cluster architectures
Authors: Xiaohan Qin, Jean-Loup Baer
Venue: ACM SIGMETRICS Performance Evaluation Review (1997)

This paper investigates the performance of shared-memory cluster-based architectures where each cluster is a shared-bus multiprocessor augmented with a protocol processor maintaining cache coherence across clusters. For a given number of processors, sixteen in this study, we evaluate the performance of various cluster configurations. We also consider the impact of adding a remote shared cache in each cluster. We use Mean Value Analysis to estimate the cache miss latencies of various types and the overall execution time. The service demands of shared resources are characterized in detail by examining the sub-requests issued in resolving cache misses. In addition to the architectural system parameters and the service demands on resources, the analytical model needs parameters pertinent to applications. The latter, in particular cache miss profiles, are obtained by trace-driven simulation of three benchmarks.Our results show that without remote caches the performance of cluster-based architectures is mixed. In some configurations, the negative effects of the longer latency of inter-cluster misses and of the contention on the protocol processor are too large to counter-balance the lower contention on the data buses. For two out of the three applications best results are obtained when the system has clusters of size 2 or 4. The cluster-based architectures with remote caches consistently outperform the single bus system for all 3 applications. We also exercise the model with parameters reflecting the current trend in technology making the processor relatively faster than the bus and memory. Under these new conditions, our results show a clear performance advantage for the cluster-based architectures, with or without remote caches, over single bus systems.
NP-Hardness of Some Linear Control Design Problems
Authors: Vincent Blondel, John N. Tsitsiklis
Venue: SIAM Journal on Control and Optimization (1997)

We show that some basic linear control design problems are NP-hard, implying that, unless P=NP, they cannot be solved by polynomial time algorithms. The problems that we consider include simultaneous stabilization by output feedback, stabilization by state or output feedback in the presence of bounds on the elements of the gain matrix, and decentralized control. These results are obtained by first showing that checking the existence of a stable matrix in an interval family of matrices is NP-hard.
Role model based framework design and integration
Authors: Dirk Riehle, Thomas Gross
Venue: ACM SIGPLAN Notices (1998)

Today, any large object-oriented software system is built using frameworks. Yet, designing frameworks and defining their interaction with clients remains a difficult task. A primary reason is that today's dominant modeling concept, the class, is not well suited to describe the complexity of object collaborations as it emerges in framework design and integration. We use role modeling to overcome the problems and limitations of class-based modeling. Using role models, the design of a framework and its use by clients can be described succinctly and with much better separation of concerns than with classes. Using role objects, frameworks can be integrated into use-contexts that have not been foreseen by their original designers.
The directional parameter plane transform of a height field
Authors: David W. Paglieroni
Venue: ACM Transactions on Graphics (TOG) (1998)

The linear Parameter Plane Transform (PPT) of a height field attributes an inverted cone of empty space to each height field cell. In is known that height field ray-tracing efficiency can be improved by traversing rays in steps across inverted cones of empty space. However, steps across inverted cones of empty space along rays close to the base of a steep ridge will be short, even if there are no obstructions along the line of sight, because the cones will be narrow. This weakness can be virtually eliminated by allowing the opening angles of the inverted cones of empty space to vary between sectors, i.e., by directionalizing the linear PPT. An efficient algorithm for computing the linear directional PPT of a height field is given and its properties are investigated.
Characterizing the Hermitian and Ree Unitals on 28 Points
Authors: Gary Mcguire, Vladimir D. Tonchev, Harold N. Ward
Venue: Designs, Codes and Cryptography (1998)

We prove a conjecture of Brouwer, namely that a 2-(28,4,1) design has 2&ndash;rank at least 19, with equality occuring if and only if the design is the Ree unital. We give a similar characterization of the Hermitian unital.
Group-guaranteed channel capacity in multimedia storage servers
Authors: Athanassios K. Tsiolis, Mary K. Vernon
Venue: ACM SIGMETRICS Performance Evaluation Review (1997)

One of the open questions in the design of multimedia storage servers is in what order to serve incoming requests. Given the capability provided by the disk layout and scheduling algorithms to serve multiple streams simultaneously, improved request scheduling algorithms can reduce customer waiting times. This results in better service and/or lower customer loss. In this paper we define a new class of request scheduling algorithms, called Group-Guaranteed Server Capacity (GGSC), that preassign server channel capacity to groups of objects. We also define a particular formal method for computing the assigned capacities to achieve a given performance objective. We observe that the FCFS policy can provide the precise time of service to incoming customer requests. Under this assumption, we compare the performance of one of the new GGSC algorithms, GGSCW-FCFS, against FCFS and against two other recently proposed scheduling algorithms: Maximum Factored Queue length (MFQ), and the FCFS-n algorithm that preassigns capacity only to each of the n most popular objects. The algorithms are compared for both competitive market and captured audience environments.Key findings of the algorithm comparisons are that: (1) FCFS-n has no advantage over FCFS if FCFS gives time of service guarantees to arriving customers, (2) FCFS and GGSCW-FCFS are superior to MFQ for both competitive and captive audience environments, (3) for competitive servers that are configured for customer loss less than 10%, FCFS is superior to all other algorithms examined in this paper, and (4) for captive audience environments that have objects with variable playback length, GGSCW-FCFS is the most promising of the policies considered in this paper. The conclusions for FCFS-n and MFQ differ from previous work because we focus on competitive environments with customer loss under 10%, we assume FCFS can provide time of service guarantees to all arriving customers, and we consider the distribution of customer waiting time as well as the average waiting time.
Song of the whale: parallel processing using APL2
Authors: Per Gjerløv, Izabela Meisel
Venue: ACM SIGAPL APL Quote Quad (1996)

APL2 has often been used in a credit course at the Technical University of Denmark. The objective of the course exercise has been to analyze the vocalizations of Sperm Whales. In January 1996 the course was run again, this time using the IBM SP/2 supercomputer to solve the problem, and in this course an additional objective was to utilize the possibilities of this powerful parallel computer.During the three weeks of the course the students learned the APL language, solved a non-trivial problem, used a very powerful computer for the solution and wrote excellent and detailed reports.
Nosie and signal integrity in deep submicron design (panel)
Authors: William E. Guthrie, Massaud Pedram, Wayne Dai, Rakesh Chadha, Jason Cong, Charlie Xiaoli Huang, Anirudh Devgan, Tom Mozdzen, Andreq Yang
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

Sub-half-micron process technologies are creating a fundamentalshift in the problems faced by IC designers andfabricators.As geometries shrink, signal integrity (SI)and noise play a critical role in determining IC performance.Without accurate interconnect data and detailednoise analysis tools, designers cannot assess the quality oftheir designs and/or new processes.This panel will offer designers an opportunity to understandthe complex analysis and design issues that surroundthe noise and signal integrity problem.
Efficient formulation for optimal modulo schedulers
Authors: Alexandre E. Eichenberger, Edward S. Davidson
Venue: Proceedings of the ACM SIGPLAN 1997 conference on Programming language design and implementation (1997)

Modulo scheduling algorithms based on optimal solvers have been proposed to investigate and tune the performance of modulo scheduling heuristics. While recent advances have broadened the scope for which the optimal approach is applicable, this approach increasingly suffers from large execution times. In this paper, we propose a more efficient formulation of the modulo scheduling space that significantly decreases the execution time of solvers based on integer linear programs. For example, the total execution time is reduced by a factor of 8.6 when 782 loops from the Perfect Club, SPEC, and Livermore Fortran Kernels are scheduled for minimum register requirements using the more efficient formulation instead of the traditional formulation. Experimental evidence further indicates that significantly larger loops can be scheduled under realistic machine constraints.
A quantitative approach to functional debugging
Authors: Darko Kirovski, Miodrag Potkonjak
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

We introduce a novel cut-based debugging paradigm. It coordinates design emulation and simulation and enables fast transition from one to another. Emulation or functional implementation is used for fast application execution; simulation provides complete design observability and controllability. The implementation of the new debugging approach poses several CAD tasks. We formulate the optimization tasks and develop constraint-based heuristics to solve them. Effectiveness of the approach is demonstrated on a set of designs.
Cluster refinement for block placement
Authors: Jin Xu, Pei-Ning Guo, Chung-Kuan Cheng
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

We propose an iterative optimization approach for mixedmacro-cell and standard-cell placement, which minimizes the chipsize and interconnection wire length at the same time. We present abranch-and-bound algorithm which efficiently searches for the optimalsolution by evaluating all of the possible configurations on theselected cluster to minimize the gap distance between the ceilingand the floor. A virtual grid and permutation order are generateddynamically to eliminate redundant branches, which was the causeof much higher complexity in other approaches. Experimentalresults on the MCNC benchmark circuits show that the algorithmachieves very competitive results to manual design.