ppxscal/embedding_network huggingface dataset:
Model and analysis for combined package and on-chip power grid simulation
Authors: Rajendran Panda, David Blaauw, Rajat Chaudhry, Vladimir Zolotov, Brian Young, Ravi Ramaraju
Venue: Proceedings of the 2000 international symposium on Low power electronics and design (2000)

We present new modeling and simulation techniques to improve the accuracy and efficiency of transient analysis of large power disðtribution grids. These include an accurate model for the inherent decoupling capacitance of non-switching devices, as well as a staðtistical switching current model for the switching devices. Moreðover, three new simulation techniques are presented for problem size-reduction and speed-up. Results of application of these techðniques on three PowerPCtmmicroprocessors are also presented.
Snakes and sandwiches: optimal clustering strategies for a data warehouse
Authors: H. V. Jagadish, Laks V. S. Lakshmanan, Divesh Srivastava
Venue: ACM SIGMOD Record (1999)

Physical layout of data is a crucial determinant of performance in a data warehouse. The optimal clustering of data on disk, for minimizing expected I/O, depends on the query workload. In practice, we often have a reasonable sense of the likelihood of different classes of queries, e.g., 40% of the queries concern calls made from some specific telephone number in some month. In this paper, we address the problem of finding an optimal clustering of records of a fact table on disk, given an expected workload in the form of a probability distribution over query classes. Attributes in a data warehouse fact table typically have hierarchies defined on them (by means of auxiliary dimension tables). The product of the dimensional hierarchy levels forms a lattice and leads to a natural notion of query classes. Optimal clustering in this context is a combinatorially explosive problem with a huge search space (doubly exponential in number of hierarchy levels). We identify an important subclass of clustering strategies called lattice paths, and present a dynamic programming algorithm for finding the optimal lattice path clustering, in time linear in the lattice size. We additionally propose a technique called snaking, which when applied to a lattice path, always reduces its cost. For a representative class of star schemas, we show that for every workload, there is a snaked lattice path which is globally optimal. Further, we prove that the clustering obtained by applying snaking to the optimal lattice path is never much worse than the globally optimal snaked lattice path clustering. We complement our analyses and validate the practical utility of our techniques with experiments using TPC-D benchmark data.
A semi-automated approach to online assessment
Authors: David Jackson
Venue: ACM SIGCSE Bulletin (2000)

Desirable though fully automated assessment of student programming assignments is, it is an area that is beset by difficulties. While it is not contested that some aspects of assessment can be performed much more efficiently and accurately by computer, there are many others that still require human involvement. We have therefore designed a system that combines the strengths of the two approaches, the assessment software calling upon the skills of the human tutor where necessary to make sensible judgements. The technique has been used successfully on a systems programming course for several years, and student feedback has been supportive.
A usage based analysis of CoRR
Authors: Les Carr, Steve Hitchcock, Wendy Hall, Stevan Harnad
Venue: ACM Journal of Computer Documentation (JCD) (2000)

Based on an empirical analysis of author usage of CoRR, and of its predecessor in the Los Alamos eprint archives, it is shown that CoRR has not yet been able to match the early growth of the Los Alamos physics archives. Some of the reasons are implicit in Halpern s paper,and we explore them further here. In particular,we refer to the need to promote CoRR more effectively for its intended community computer scientists in universities, industrial research labs and in government. We take up some points of detail on this new world of open archiving concerning central versus distributed self-archiving,publication, the restructuring of the journal publishers review and copyright.
Transient fault detection via simultaneous multithreading
Authors: Steven K. Reinhardt, Shubhendu S. Mukherjee
Venue: ACM SIGARCH Computer Architecture News (2000)

Smaller feature sizes, reduced voltage levels, higher transistor counts, and reduced noise margins make future generations of microprocessors increasingly prone to transient hardware faults. Most commercial fault-tolerant computers use fully replicated hardware components to detect microprocessor faults. The components are lockstepped (cycle-by-cycle synchronized) to ensure that, in each cycle, they perform the same operation on the same inputs, producing the same outputs in the absence of faults. Unfortunately, for a given hardware budget, full replication reduces performance by statically partitioning resources among redundant operations. We demonstrate that a Simultaneous and Redundantly Threaded (SRT) processor&mdash;derived from a Simultaneous Multithreaded (SMT) processor&mdash;provides transient fault coverage with significantly higher performance. An SRT processor provides transient fault coverage by running identical copies of the same program simultaneously as independent threads. An SRT processor provides higher performance because it dynamically schedules its hardware resources among the redundant copies. However, dynamic scheduling makes it difficult to implement lockstepping, because corresponding instructions from redundant threads may not execute in the same cycle or in the same order. This paper makes four contributions to the design of SRT processors. First, we introduce the concept of the sphere of replication, which abstracts both the physical redundancy of a lockstepped system and the logical redundancy of an SRT processor. This framework aids in identifying the scope of fault coverage and the input and output values requiring special handling. Second, we identify two viable spheres of replication in an SRT processor, and show that one of them provides fault detection while checking only committed stores and uncached loads. Third, we identify the need for consistent replication of load values, and propose and evaluate two new mechanisms for satisfying this requirement. Finally, we propose and evaluate two mechanisms&mdash;slack fetch and branch outcome queue&mdash;that enhance the performance of an SRT processor by allowing one thread to prefetch cache misses and branch results for the other thread. Our results with 11 SPEC95 benchmarks show that an SRT processor can outperform an equivalently sized, on-chip, hardware-replicated solution by 16% on average, with a maximum benefit of up to 29%.
The Chebyshev expansion based passive model for distributed interconnect networks
Authors: Janet M. Wang, Ernest S. Kuh, Qingjian Yu
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

A new Chebyshev expansion based model for distributed interconnect networks is presented in this paper. Unlike the moment methods, this new model is optimal and it does not require the knowledge of expansion points. An automatic order selection scheme is also included in the new model. By using the integrated congruence transform, we guarantee the passivity of the new model for distributed interconnect networks. Because of the orthogonality of Chebyshev polynomials, the Modified Gram-Schmidt algorithm can be simplified. In the experimental examples, the new model is found to be accurate and efficient.
Escaping the software tar pit: model clashes and how to avoid them
Authors: Barry Boehm
Venue: ACM SIGSOFT Software Engineering Notes (1999)

"No scene from prehistory is quite so vivid as that of the mortal struggles of great beasts in the tar pits hellip; Large system programming has over the past decade been such a tar pit, and many great and powerful beasts have thrashed violently in it hellip;"Everyone seems to have been surprised by the stickiness of the problem, and it is hard to discern the nature of it. But we must try to understand it if we are to solve it."Fred Brooks, 1975Several recent books and reports have confirmed that the software tar pit is at least as hazardous today as it was in 1975. Our research into several classes of models used to guide software development (product models, process models, property models, success models), has convinced us that the concept of model clashes among these classes of models helps explain much of the stickiness of the software tar-pit problem.We have been developing and experimentally evolving an approach called MBASE -- Model-Based (System) Architecting and Software Engineering -- which helps identify and avoid software model clashes. Section 2 of this paper introduces the concept of model clashes, and provides examples of common clashes for each combination of product, process, property, and success model. Sections 3 and 4 introduce the MBASE approach for endowing a software project with a mutually supportive set of models, and illustrate the application of MBASE to an example corporate resource scheduling system. Section 5 summarizes the results of applying the MBASE approach to a family of small digital library projects. Section 6 presents conclusions to date.
Hybrid concurrency control for abstract data types
Authors: Maurice P. Herlihy, William E. Weihl
Venue: Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1988)

We define a new locking protocol that permits more concurrency than existing commutativity-based protocols. The protocol uses timestamps generated when transactions commit to provide more information about the serialization order of transactions, and hence to weaken the constraints on conflicts. In addition, the protocol permits operations to be both partial and non-deterministic, and it permits results of operations to be used in choosing locks. The protocol exploits type-specific properties of objects, necessary and sufficient constraints on lock conflicts are defined directly from a data type specification. We give a complete formal description of the protocol, encompassing both concurrency control and recovery, and prove that the protocol satisfies hybrid atomicity, a local atomicity property that combines aspects of static and dynamic atomic protocols. We also show that the protocol is optimal in the sense that no hybrid atomic locking scheme can permit more concurrency.
Recognizing Perfect 2-Split Graphs
Authors: Chính T. Hoàng, Van Bang Le
Venue: SIAM Journal on Discrete Mathematics (2000)

A graph is a split graph if its vertices can be partitioned into a clique and a stable set. A graph is a k-split graph if its vertices can be partitioned into k sets, each of which induces a split graph. We show that the strong perfect graph conjecture is true for 2-split graphs and we design a polynomial algorithm to recognize a perfect 2-split graph.
Navigating through triangle meshes implemented as linear quadtrees
Authors: Michael Lee, Hanan Samet
Venue: ACM Transactions on Graphics (TOG) (2000)

Techniques are presented for navigating between adjacent triangles of greater or equal size in a hierarchical triangle mesh where the triangles are obtained by a recursive quadtree-like subdivision of the underlying space into four equilateral triangles. These techniques are useful in a number of applications, including finite element analysis, ray tracing, and the modeling of spherical data. The operations are implemented in a manner analogous to that used in a quadtree representation of data on the two-dimensional plane where the underlying space is tessellated into a square mesh. A new technique is described for labeling the triangles, which is useful in implementing the quadtree triangle mesh as a linear quadtree (i.e., a pointer-less quadtree); the navigation can then take place in this linear quadtree. When the neighbors are of equal size, the algorithms have a worst-case constant time complexity. The algorithms are very efficient, as they make use of just a few bit manipulation operations, and can be implemented in hardware using just a few machine language instructions. The use of these techniques when modeling spherical data by projecting it onto the faces of a regular solid whose faces are equilateral triangles, which are represented as quadtree triangle meshes, is discussed in detail. The methods are applicable to the icosahedron, octahedron, and tetrahedron. The difference lies in the way transitions are made between the faces of the polyhedron. However, regardless of the type of polyhedron, the computational complexity of the methods is the same.
Predicting the QoS of an electronic commerce server: those mean percentiles
Authors: Diwakar Krishnamurthy, Jerome Rolia
Venue: ACM SIGMETRICS Performance Evaluation Review (1998)

This paper presents a case study on Quality of Service (QoS) measures and Service Level Agreements (SLA) for an electronic commerce server. Electronic commerce systems typically rely on a combination of an HTTP server and a database server that may be integrated with other enterprise information resources. Some interactions with these systems cause requests for static HTML pages. Others cause significant amounts of database processing. Response time percentiles are well-accepted measures of QoS for such requests. In this paper we measure the behavior of an electronic commerce server under several controlled loads and study response time measures for several workload abstractions. Response time measures are captured for individual URLs, groups of functionally related URLs, and for sequences of URLs. We consider the utility of these workload abstractions for providing SLA. We also show that empirical evidence of server behavior in conjunction with analytic modeling techniques may be useful to predict the 90-percentile of response times for sequence based workload classes. The model predictions could be used to support realtime call admission algorithms.
Monochromatic Paths and Triangulated Graphs
Authors: Shimon Even, Ami Litman, Arnold L. Rosenberg
Venue: SIAM Journal on Discrete Mathematics (1998)

This paper considers two properties of graphs, one geometrical and one topological, and shows that they are strongly related. Let G be a graph with four distinguished and distinct vertices, w1, w2, b1, b2. Consider the two properties, TRI+(G) and MONO(G), defined as follows. TRI+(G): There is a planar drawing of G such that all 3-cycles of G are faces; all faces of G are triangles except for the single face which is the 4-cycle (w1-b1-w2-b2-w1). MONO(G): G contains the 4-cycle (w1-b1-w2-b2-w1) and, for any labeling of the vertices of G by the colors {white, black} such that w1 and w2 are white, while b1 and b2 are black, precisely one of the following holds. There is a path of white vertices connecting w1 and w2. There is a path of black vertices connecting b1 and b2. Our main result is that a graph G enjoys property TRI+(G) if and only if it is minimal with respect to property MONO. Building on this, we show that one can decide in polynomial time whether or not a given graph G has property MONO(G).
The Nonconvexities Problem in Adaptive Control Models: A SimpleComputational Solution
Authors: Marco P. Tucci
Venue: Computational Economics (1998)

In the last few years new attention has been paid to the problem of nonconvexities in the cost-to-go function in adaptive control models. Using analytical methods, it can be found that nonconvexities are caused by the probing component of the total cost-to-go (Mizrach, 1991) or by the cautionary component of the cost-to-go (Amman and Kendrick, 1995). In this paper a simple algorithm based on the usual gradient methods, able to detect the presence of nonconvexities in an adaptive control problem and to find the global optimum, is presented and its effectiveness is studied in a Monte Carlo experiment. The simulations reported show that this code seems well suited for most of the situations likely to occur in empirical studies. In the future this algorithm must be tested in larger models to see if these results hold in more complex situations.
Signal design and system operation of Globalstar versus IS-95 CDMA&mdash;similarities and differences
Authors: Leonard Schiff, A. Chockalingam
Venue: Wireless Networks (2000)

The Globalstar^{TM} system provides telephone and data services to and from mobile and fixed users in the area between &plusmn; 70 degrees latitude. Connection between user terminals and the PSTN is established through fixed terrestrial gateways via a constellation of low earth orbiting &lpar;LEO&rpar; satellites. Globalstar uses an extension of the IS&dash;95 CDMA standard that is used in terrestrial digital cellular systems. The LEO satellite link is sufficiently different from the terrestrial cellular link that certain departures from IS&dash;95 were needed both in signal design as well as in system operation. This paper describes some of the similarities and differences of Globalstar air interface versus IS&dash;95.
Audio Feature Extraction and Analysis for Scene Segmentation and Classification
Authors: Zhu Liu, Yao Wang, Tsuhan Chen
Venue: Journal of VLSI Signal Processing Systems (1998)

Understanding of the scene content of a video sequence is very important for content-based indexing and retrieval of multimedia databases. Research in this area in the past several years has focused on the use of speech recognition and image analysis techniques. As a complimentary effort to the prior work, we have focused on using the associated audio information (mainly the nonspeech portion) for video scene analysis. As an example, we consider the problem of discriminating five types of TV programs, namely commercials, basketball games, football games, news reports, and weather forecasts. A set of low-level audio features are proposed for characterizing semantic contents of short audio clips. The linear separability of different classes under the proposed feature space is examined using a clustering analysis. The effective features are identified by evaluating the intracluster and intercluster scattering matrices of the feature space. Using these features, a neural net classifier was successful in separating the above five types of TV programs. By evaluating the changes between the feature vectors of adjacent clips, we also can identify scene breaks in an audio sequence quite accurately. These results demonstrate the capability of the proposed audio features for characterizing the semantic content of an audio sequence.
A market-driven approach to teaching software components engineering
Authors: Nick V. Flor, F. Javier Lerch, Se-Joon Hong
Venue: Annals of Software Engineering (1999)

The emergence of software component standards and tools for creating software components is leading to an increasing number of software component developers. Traditional software engineering education, however, emphasizes methods for developing large software packages. It is not clear whether such methods are appropriate for developing components. New techniques may be needed to teach the skills necessary for component development. We identify two skills software developers need to successfully develop components, which are not emphasized in traditional software engineering education: (a) uncovering multiple&dash;customer domain semantics&semi; and (b) making explicit multiple&dash;customer framework semantics. Both skills are multiple constraint satisfaction problems. We further argue that training students to produce and market components in a simulated software components marketplace &ndash; rather than the more conventional &ldquo;classroom teaching&rdquo; + &ldquo;component homework assignments/projects&rdquo; &ndash; is an effective way of teaching such skills. We then describe an environment we created called SofTrade that simulates a components market and allows students to acquire the necessary skills. We provide a detailed case study of how a student component&dash;producer team used market feedback to determine domain and framework semantics. We end by discussing the importance of market&dash;driven approaches for teaching software components engineering and how such approaches fit into existing software engineering curricula.
Multiplierless Realization of Linear DSP Transforms by Using Common Two-Term Expressions
Authors: Arda Yurdakul, Günhan Dündar
Venue: Journal of VLSI Signal Processing Systems (1999)

Recently, most DSP systems have used multirate signal processing techniques or transforms for reducing computational complexity without compromising the system quality. In these techniques, realizing each constant separately is a redundant process as some constants appear more than once, and increases area and power consumption of the system. This paper introduces the concept of handling all coefficients in the system at the same time. To do this, the two-term expressions of constants in a system for adder and shifter minimization is presented.
DynaMat: a dynamic view management system for data warehouses
Authors: Yannis Kotidis, Nick Roussopoulos
Venue: ACM SIGMOD Record (1999)

Pre-computation and materialization of views with aggregate functions is a common technique in Data Warehouses. Due to the complex structure of the warehouse and the different profiles of the users who submit queries, there is need for tools that will automate the selection and management of the materialized data. In this paper we present DynaMat, a system that dynamically materializes information at multiple levels of granularity in order to match the demand (workload) but also takes into account the maintenance restrictions for the warehouse, such as down time to update the views and space availability. DynaMat unifies the view selection and the view maintenance problems under a single framework using a novel &ldquo;goodness&rdquo; measure for the materialized views. DynaMat constantly monitors incoming queries and materializes the best set of views subject to the space constraints. During updates, DynaMat reconciles the current materialized view selection and refreshes the most beneficial subset of it within a given maintenance window. We compare DynaMat against a system that is given all queries in advance and the pre-computed optimal static view selection. The comparison is made based on a new metric, the Detailed Cost Savings Ratio introduced for quantifying the benefits of view materialization against incoming queries. These experiments show that DynaMat's dynamic view selection outperforms the optimal static view selection and thus, any sub-optimal static algorithm that has appeared in the literature.
A Method of Formal Verification of Cryptographic Circuits
Authors: Kanji Hirabayashi
Venue: Journal of Electronic Testing: Theory and Applications (1998)

In this letter we report the formal verification of encryption and decryption circuits. After we describe algebraically a simple modular arithmetic circuit at both function and logic levels, we apply the symbolic manipulation of Mathematica.
A Solution-Based Triangular and Tetrahedral Mesh Quality Indicator
Authors: M. Berzins
Venue: SIAM Journal on Scientific Computing (1998)

A new mesh quality measure for triangular and tetrahedral meshes is presented. This mesh quality measure is based on both geometrical and solution information and is derived by considering the error when linear triangular and tetrahedral elements are used to approximate a quadratic function. The new measure is shown to be related to existing measures of mesh quality but with the advantage that local solution information in the form of scaled derivatives along edges is taken into account.