ppxscal/embedding_network huggingface dataset:
Beyond Software Performance Visualization
Authors: Marc Abrams, Timothy Lee, Horacio Cadiz, Krishna Ganugapati
Venue:  (1994)

Performance visualization tools of the last decade have yielded new insights into the new behavior of sequential, parallel, and distributed programs. However, they have three inherent limitations: (1) They only display what happened in one execution of a program. (This is dangerous when analyzing concurrent applications, which are prone to non-deterministic behavior.) (2) A human uses one or more bandwidth-limited senses with a visualization tool. (This limits the scalability of a visualization tool.) (3) The relationship of "interesting" program events are often separated in time by other events; thus discerning time dependent behavior often hinges on finding the "right" visualization - a possibly time-comsuming activity. CHITRA93 complements visualization systems, while alleviating these limitations. CHITRA93 analyzes a set (or ensemble) of traces by combining the visualization of a few traces with a statistical analysis of the entire ensemble (overcoming (1)); and reduces the ensemble to empirical models that capture the time dependent relationships of "interesting" program events through application, programming language, and computer architecture independent analysis tools (addressing (2) and (3)). CHITRA93 incorporates: transforms, such as aggregation, that simplify the ensemble and reduce the state space size of the models generated; a user interface that allows some transforms to be selected by editing the visualization with a mouse; homogeneity tests that allow partitioning of an ensemble; an efficient semi-Markov model generation algorithm whose computation time is linear in the sum of the lengths of the traces comprising the ensemble; and a CHAID-based model that can fathom non-Markovian relationships among transitions in the traces. The use of CHITRA93 is demonstrated by partitioning ten parallel database traces with nearly 8,000 states into two homogeneous subsets, each modeled by a 20 state irreducible, periodic (non-Markovian) stochastic process.
Error Recovery in Critical Infrastructure Systems
Authors: John C. Knight, Matthew C. Elder, Xing Du
Venue:  (1999)

Critical infrastructure applications provide services upon which society depends heavily; such applications require survivability in the face of faults that might cause a loss of service. These applications are themselves dependent on distributed information systems for all aspects of their operation and so survivability of the information systems is an important issue. Fault tolerance is a key mechanism by which survivability can be achieved in these information systems. Much of the literature on fault-tolerant distributed systems focuses on local error recovery by masking the effects of faults. We describe a direction for error recovery in the face of catastrophic faults, where the effects of the faults cannot be masked using available resources. The goal is to provide continued service that is either an alternate or degraded service by reconfiguring the system rather than masking faults. We outline the requirements for a reconfigurable system architecture and present an error recovery system that enables systematic structuring of error recovery specifications and implementations.
A Representation and Algorithm for Exact Computation of Cascaded Polygon Intersections with Fixed Storage Requirements
Authors: Clifford A. Shaffer, Charles D. Feustel
Venue:  (1991)

Given a collection of polygons (or a collection of sets of polygons) with vertex points specified to some fixed-point precision, a technique is presented for accurately representing the intersection points formed by elements in the collection. In particular, we recognize that in 2D, the result of a series of intersections between polygons must be composed of line segments that are part of the line segments making up the original polygons. While our techniques greatly improve the accuracy of floating point representations for intersection points, we also provide algorithms based on rational arithmetic that compute these intersection points exactly. The storage required to represent an intersection vertex is slightly greater than four times the number of bits in the input resolution. Furthermore, no intermediate quantity requires resolution slightly greater than four times the resolution resolution of input vertex values, so implementation on existing computers at practical resolution can easily be done. Cascaded intersection operations do not require ever greater amounts of storage for vertex points, as would normally be required by a rational arithmetic approach. We also prove that a similar approach is not possible for any reasonable set of rotations.
Automatic Design of Custom Wide-Issue Counterflow Pipelines
Authors: Bruce R. Childers, Jack W. Davidson
Venue:  (1999)

Application-specific processor design is a promising approach for meeting the performance and cost goals of a system. Application-specific integrated processors (ASIP''s) are especially promising for embedded systems (e.g., automobile control systems, avionics, cellular phones, etc.) where a small increase in performance and decrease in cost can have a large impact on a product''s viability. Sutherland, Sproull, and Molnar have proposed a new pipeline organization called the Counterflow Pipeline (CFP) that may be appropriate for ASIP design. This paper extends the original CFP microarchitecture to a very long instruction word (VLIW) organization for the custom design of instruction-level parallel processors tailored to the requirements of computation-intensive inner loops. First, we describe our extensions to the CFP to support automatic customization of application-specific VLIW processors. Second, we present an automatic design system that customizes a wide-issue counterflow pipeline (WCFP) to the resource and data flow requirements of a software pipeline loop. Third, we show that custom asynchronous WCFP''s achieve cycles per operation measurements that are competitive with custom VLIW organizations at a potentially low design complexity. Finally, the paper describes several enhancements that can be made to WCFP''s to further improve performance of kernel loops.
Forbidding and enforcing in membrane computing
Authors: Matteo Cavaliere, Nataša Jonoska
Venue: Natural Computing: an international journal (2003)

Motivated by biochemistry and the non-deterministic reactions between molecules, the authors in (Ehrenfeucht and Rozenberg, 2003) introduced the concept of forbidding-enforcing systems (fe-systems) that define families of languages. Using the same concept we propose to study forbidding and enforcing within membrane systems. Two approaches are presented; in the first case the membrane system generates families of languages and in the second case the membrane system generates a single language. We show that by using forbidding-enforcing in membranes, families of languages that cannot be defined by any fe-system can be generated. When a single language is generated, we show that SAT can be solved in a constant time (at price of using an exponential space). Also we show an example of a context-free language that can be generated without any forbidders.
Automatic Knowledge Acquisition
Authors: Mike Alder, Christopher J.S. deSilva, Yianni Attikiouzel
Venue:  (1990)

This paper considers the abstract and practical issues involved in automatically generating higher level descriptions of data strutures from lower levels. The applications are restricted to one (string) and two (pixel array) dimensional data structures and are incomplete.
Approximate Time-Parallel Simulation of Queueing Systems with Losses
Authors: Jain J. Wang, Marc Abrams
Venue:  (1992)

This paper presents a guideline of a partial state matching approach for time-parallel simulation. Two algorithms using this approach to simulate FCFS G/G/1/K and G/D/1/K queues in which arriving customers that find the queue full are lost are proposed. Experiments with M/M/1/K and M/D/1/K models show that the performance of the algorithms in terms of convergence speed and accuracy is good in general cases. The worst performance of the algorithms occurs when traffic intensity approaches one. An argument is made to explain this phenomenon.
Comparison of an Object-Oriented Programming Language to a Procedural Programming Language for Effectiveness in Program Maintenance
Authors: Sallie M. Henry, Matthew C. Humphrey
Venue:  (1988)

New software tools and methodologies make claims that managers often believe intuitively, without evidence. Many unsupported claims have been made about object-oriented programming. However, without scientific evidence, it is impossible to accept these claims as valid. Although experimentation has been done in the past, most of the research is very recent and the most relevant research has serious drawbacks. This paper describes an experiment which compares the maintainability of two functionally equivalent systems in order to explore the claim that systems developed with object-oriented languages are more easily maintained than those programmed with procedural languages. We found supporting evidence that programmers produce more maintainable code with an object oriented language than a standard procedural language.
Bayesian Latent Semantic Analysis of Multimedia Databases
Authors: Nando de Freitas, Kobus Barnard
Venue:  (2001)

We present a Bayesian mixture model for probabilistic latent semantic analysis of documents with images and text. The Bayesian perspective allows us to perform automatic regularisation to obtain sparser and more coherent clustering models. It also enables us to encode a priori knowledge, such as word and image preferences. The learnt model can be used for browsing digital databases, information retrieval with image and/or text queries, image annotation (adding words to an image) and text illustration (adding images to a text).
Accountability and Control of Process Creation in the Legion Metasystem
Authors: Marty Humphrey, Frederick Knabe, Adam Ferrari, Andrew Grimshaw
Venue:  (1999)

A metacomputing environment, or metasystem, is a collection of geographically separated resources (people, computers, devices, databases) connected by one or more high-speed networks. The distinguishing feature of a metasystem is middleware that facilitates viewing the collection of resources as a single virtual machine. The traditional requirements of security mechanisms and policies in a single physical host is exacerbated in a metasystem, as the physical resources of the metasystem exist in multiple administrative domains, each with different local security requirements. This paper illustrates how the Legion metasystem both accommodates and augments local security policies specifically with regard to process creation. For example, Legion configurations for local sites with different access control mechanisms such as standard UNIX mechanisms and Kerberos are compared. Through analysis of these configurations, the inherent security trade-offs in each design are derived. These results have practical importance to sites considering any future inclusion of local resources in a global virtual computer.
Posse: A Framework for optimizing incremental view maintenance at data warehouses
Authors: K. O Abbadi
Venue:  (1999)

Incremental maintenance of materialized views consists of installing changes to the view as a result of an update to one of the base relations. This generally requires information from some or all of the other base relations comprising the view, which may be obtained by probing (i.e. querying) the base relations. In a distributed context such as a data warehouse, there may be a great deal of concurrency among updates as well as probes and replies, leading to consistency problems, for which a number of solutions have been offered. These solutions, however, have been expressed as algorithms of limited practical use because they are variously limited to restricted view queries, relational semantics, and limited concurrency. We propose the POSSE framework in which many of these limitations are removed, and in which the techniques of distributed query optimization can be brought to bear on the problem. To this end, we show how for a particular method of consistent probing it is possible to have the power of SQL view queries with multiset semantics, and at the same time have available a spectrum of concurrency from none at all as in some previously proposed solutions to the maximum concurrency obtained by issuing all probes in parallel. We then show how optimization of the probing process can be used to select various degrees of concurrency for the desired tradeoffs of concurrency against processing cost and message size.
Development and Testing of an Evaluation Procedure for User InterfaceManagement (UIMS)
Authors: Deborah Hix, Kay C. Tan, Robert S. Schulman
Venue:  (1989)

A user interface management system or UIMS is an interactive system for supporting the design, production, and execution of human-computer interfaces. This paper reports on the development and empirical testing of an evaluation procedure to produce quantifiable criteria for evaluating and comparing UIMS. The form-based evaluation procedure results in quantitative ratings along two dimensions: functionality and usability. Specification/implementation techniques used by a UIMS are also quantitatively rated. An empirical study has indicated that the procedure produces reliable, useful results.
S2GPS: Slow-Start Generalized Processor Sharing
Authors: A. Stamoulis, J. Liebeher
Venue:  (1997)

Packet scheduling methods that approximate Generalized Processor Sharing (GPS) are currently the focus of much research in the area of Quality-of-Service (QoS) networks. The ability of GPS schedulers to provide rate guarantees as well as delay guarantees meets the demand of many network applications. This paper addresses a shortcoming of GPS which can have significant impact on the service provided by GPS, however, which has been given little attention. Since, with GPS, the service rate received by a session is proportional to the number of backlogged sessions in the system, the service rate of a session may change abruptly if some other session becomes active. This may result in abrupt increases of delay of consecutive packets. In this paper, we propose a new scheduler, called {\it Slow-Start GPS} (S$^2$GPS), which alleviates the problem of abrupt decreases of service rates when new sessions start transmitting. S$^2$GPS is a modification of GPS where a session does not receive its guaranteed service rate immediately after it becomes active. Instead, the service rate of a session is gradually increased. We show that this prevents an abrupt delay increase of the other sessions. We derive delay bounds for sessions constrained by leaky buckets and we express quantitatively the advantages of the S$^2$GPS scheduling discipline.
A tool for assessing the consistency of websites
Authors: Sibylle Steinau, Oscar Díaz, Juan J. Rodríguez, Felipe Ibáñez
Venue: Enterprise information systems IV (2003)

Usability is becoming an increasingly important design factor for web sites. However time and budget contstraints for web projects prevents the hiring of usability professionals to conduct tests that are costly and time consuming to perform. A number of automatic usability assessment tools have been developed most of which offer reports on a per-page basis. However, they fail to provide inter-page assessments to test, for example the consistency of the site. Consistency refers to the extent to which a set of pages share a common layout. This work presents CAT, a Consistency Analysis Tool that, besides providing static, page-based usability measures, strives to assess the consistency of a website using Java and XSLT. The tool is based on a consistency model which is updated every time a page has been processed. Consistency testing involves collating the page with this model, reporting mismatches with the consistency attributes and adapting the model as new features are encountered for the first time.
Modeling Transcient Trace Data
Authors: Mathur Anup, Abrams Marc
Venue:  (1996)

This paper introduces a novel technique to construct an empirical workload model fitting time-varying (transient) trace data. The trace can be a categorical or numerical time-series. We model the trace as a Piecewise Independent stochastic process. To estimate the parameters for our model we first build a Rate Evolution Graph from the trace data. Piecewise linear regression is then used to construct a joint time-dependent probablity mass function for the trace data. Two methods are proposed to build a parsi- monious model. The modeling approach is demonstrated by the application of our model to twelve traces from the performance analysis domain.
An Intensity-Based Direct Method for Depth Estimation from Image Sequenceswith Kalman Filtering
Authors: An Luo, Hans Burkhardt
Venue:  (1995)

This paper presents a new incremental algorithm for directly estimating depth maps from image sequences, which is based on the modified motion constraint equation. In order to overcome the inherent problem of the gradient-based methods which are sensitive to noise and guarantee a moderate cost, we make a scalar Kalman filtering approach with some compensation considering discontinuity and occlusion to the direct methods for recovering 3-D structures without restoring optical flow. The experiments show that the algorithm is effective and robust to noisy real image sequences.
CHIP AND PACKAGE CO-SYNTHESIS OF CLOCK NETWORKS (Ph.D. Thesis)
Authors: Qing Zhu
Venue:  (1995)

This dissertation presents the new concept of chip/package co-design for clock networks. Constructing a large flat size clock network that achieves zero skew is very challenging in VLSI design. Two new concepts are presented in this dissertation: (1) Since the package layer has far smaller RC interconnect parameters than a chip layer, placing the global clock tree on the package layer can decrease the skew, delay and wire capacitance significantly. (2) Using tolerable skew constraints between sequentially adjacent registers in synchronous circuits can simplify the clock distribution and reduce the total wire length of the clock tree significantly. We proposed a new clock distribution scheme which partitions the clock network into two levels. First, the clock terminals are partitioned into a set of clusters. For each cluster, a local on-chip clock tree is used to distribute the clock signal from a locally inserted buffer to terminals inside this cluster. The clock signal is then distributed from the main clock driver to each of local buffers by means of a global clock tree, which is routed on the package layer. Flip chip area I/O connections are used to make the connections between the global clock tree and the on-chip local clock trees. Algorithms are proposed to construct a planar equal path length tree for the global clock tree. Since it is planar, the global clock tree can be embedded on a single package layer, reducing the delay and attenuation through vias as well as sensitivity to process variations. The global clock tree is further improved iteratively to reduce the total wire length while maintaining the tolerable skew constraints. The skew constrained cut-and-link tree plays a key role in the iterative refinement. A clock sizing technique is used to decrease the skew of the global clock tree if the tolerable skew constraints are not satisfied. The optimal clock sizing problem is solved by a least square minimization method. In addition, this dissertation investigates the delay bounded minimum Steiner tree problem. Delay bounded minimum Steiner tree can be used for the interconnect tree construction when the interconnect delay becomes significant. A new iterative algorithm is proposed to construct a delay bounded minimum Steiner tree. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Approaches to combining local and evolutionary search for training neural networks: a review and some new results
Authors: Kim W. C. Ku, M. W. Mak, W. C. Siu
Venue: Advances in evolutionary computing: theory and applications (2003)

Training of neural networks by local search such as gradient-based algorithms could be difficult. This calls for the development of alternative training algorithms such as evolutionary search. However, training by evolutionary search often requires long computation time. In this chapter, we investigate the possibilities of reducing the time taken by combining the efforts of local search and evolutionary search. There are a number of attempts to combine these search strategies, but not all of them are successful. This chapter provides a critical review of these attempts. Moreover, different approaches to combining evolutionary search and local search are compared. Experimental results indicate that while the Baldwinian and the two-phase approaches are inefficient in improving the evolution process for difficult problems, the Lamarckian approach is able to speed up the training process and to improve the solution quality. In this chapter, the strength and weakness of these approaches are illustrated, and the factors affecting their efficiency and applicability are discussed.
A WEAK-CONSISTENCY ARCHITECTURE FOR DISTRIBUTED INFORMATION SERVICES
Authors: Richard A. Golding
Venue:  (1992)

Services provided on wide-area networks like the Internet present several challenges. The reliability, performance, and scalability expected of such services often requires they be implemented using multiple, replicated servers. One possible architecture implements the replicas as a {\em weak-consistency process group.} This architecture provides good scalability and availability, handles portable computer systems, and minimizes the effect of users on each other. The key principles in this architecture are component independence, a process group protocol that provides small summaries of database contents, caching database {\em slices}, and the {\em quorum multicast} client-to-server communication protocol. A distributed bibliographic database system serves as an example.
Fault Tolerance Bounds for Asynchronous Memory Consistency
Authors: J. James, A. Singh
Venue:  (1999)

A wait-free distributed algorithm is one in which every process can complete an operation in a finite number of steps. A generalization of wait-freedom is t-resilience, in which every process can complete an operation in a finite number of steps if no more than t processes fail (by stopping). We study the conditions under which algorithms that implement distributed shared memory (DSM) can be implemented resiliently and in a nonblocking manner on asynchronous systems, in which there is no known upper bound on message latencies. We derive upper bounds on the number of faults that can be tolerated by an object, based on the consistency of histories of certain forms. From these general bounds, we derive bounds for linearizability, sequential consistency, processor consistency, and some weaker memories. We show that these latter bounds are tight by displaying implementations that achieve them. The proof technique for the upper bounds is of independent interest, due to its applicability to other objects.
From the Look of Things
Authors: Alain Fournier
Venue:  (1993)

We can''t help wonder occasionally about what we do. The following is the result of such wondering, using a unique opportunity to get a paper in without much scrutiny. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player