ppxscal/embedding_network huggingface dataset:
(C,A)-Invariance of Modules over Principal Ideal Domains
Authors: Naoharu Ito, Wiland Schmale, Harald K. Wimmer
Venue: SIAM Journal on Control and Optimization (2000)

For discrete-time linear systems over a principal ideal domain, three types of (C,A)-invariance can be distinguished. Connections between these notions are investigated. For pure submodules, necessary and sufficient conditions for dynamic (C,A)-injection invariance are given. Sufficient conditions are obtained in the general case.
Delay Sensitivity of Quadratic Controllers: A Singular Perturbation Approach
Authors: Papa Momar Ndiaye, Michel Sorine
Venue: SIAM Journal on Control and Optimization (2000)

We study the variations of the quadratic performance associated to a linear differential system of retarded type for small values of the delays. From an interpretation of delays as singular perturbations of abstract evolution operators, we revisit the usual theory of representation and optimal control of retarded systems. This leads to a new parameterization of associated Riccati operators for which insight is gained in the dependence on the delays. This explicit parameterization of Riccati operators by the delays enables us to prove differentiability at zero for performance viewed as a function of the delays, in the LQ-optimal or ${\cal H}_{\infty}$ suboptimal control. In each case, the gradient is explicitly computed in terms of the nonnegative solution of the finite dimensional Riccati equation associated to the nondelay control problem. A thorough treatment is stated for the linear quadratic optimal case, and the ${\cal H}_{\infty}$ suboptimal control is presented as an application.
The nimble integration engine
Authors: Denise Draper, Alon Y. Halevy, Daniel S. Weld
Venue: ACM SIGMOD Record (2001)

The consensus that XML has become the de facto standard for data interchange will spur demand for technology that allows users to integrate data from a variety of applications, repositories, and legacy systems which are located across the corporate intranet or at partner companies on the Internet. In the past two years, Nimble Technology has developed a product for this market. Spawned from over a person-decade of data integration research, the product has been deployed at several Fortune-500 beta-customer sites. This abstract reports on the key challenges we faced in the design of our product and highlights some issues we think require more attention from the research community.
Floating-point arithmetic with 84-bit numbers
Authors: Robert T. Gregory, James L. Raney
Venue: Communications of the ACM (1964)

A classic and straightforward technique is presented which is not limited to the size or type of number representation used or multiple precision arithmetic.
Network management capabilities for switched multi-megabit data service
Authors: David M. Piscitello, Patrick J. Sher
Venue: ACM SIGCOMM Computer Communication Review (1990)

This paper discusses network management capabilities for a specific BOC data service, SMDS, and the role that a BOC network providing this service can play in the overall management strategy of a subscriber owned and operated data network. The paper describes user needs for managing the computing equipment and communications services that comprise a data network, and suggests several ways in which a BOC network could offer network management features that complement and are synergistic with the management practices applied in today's data networks. A set of candidate management information is discussed that could be offered by a BOC network providing SMDS to complement the base of information essential to maintaining the operational data network of the customer.
The Approximate Inverse in Action with an Application to Computerized Tomography
Authors: Andreas Rieder, Thomas Schuster
Venue: SIAM Journal on Numerical Analysis (2000)

The approximate inverse is a scheme to obtain stable numerical inversion formulae for linear operator equations of the first kind. Yet, in some applications the computation of a crucial ingredient, the reconstruction kernel, is time-consuming and instable. It may even happen that the kernel does not exist for a particular semidiscrete system. To cure this dilemma we propose and analyze a technique that is based on a singular value decomposition of the underlying operator. The results are applied to the reconstruction problem in 2D-computerized tomography where they enable the design of reconstruction filters and lead to a novel error analysis of the filtered backprojection algorithm.
A record and file partitioning model
Authors: Jair M. Babad
Venue: Communications of the ACM (1977)

One of the main objectives in the design of a file system is the reduction of storage and data transfer costs. This paper presents a model in which several requests access the file system, and each request requires information from one or more variable length data-items. The probabilities of access and the distribution of each data-item's length are assumed to be known, and to be mutually independent. The file system uses one or more storage devices, and each record may be partitioned into subrecords that are stored on different devices. One of the subrecords is designated as the primary record; when a request for a record is made, the primary record is first accessed, and other sub-records are accessed only if the pertinent information is not stored in the primary record. The model that is presented in this paper, both as a nonlinear programming model and a mixed integer programming model, is a very general one; several types of file systems may be derived from it by an appropriate selection of its parameters. This model has already been used in the optimization of library routines' storage at a large scale operating system.
Triform programs
Authors: Dan W. Crockett
Venue: Communications of the ACM (1981)

The concept that three process functions&mdash;initialization, production, and completion&mdash;and a separate supervisory control function are sufficient to describe the execution of a program is the basis for Triform Program design. Triform programs are composed of modules arranged in a trifurcate tree structure with each branch devoted to the performance of one and only one of the process functions. The root of the program tree is a control module which supervises process-function execution. Such trifurcate tree structures are shown to be minimum complexity structures.
Processing location-dependent queries in a multi-cell wireless enviroment
Authors: Baihua Zheng, Dik Lun Lee
Venue: Proceedings of the 2nd ACM international workshop on Data engineering for wireless and mobile access (2001)

We develop several methods for scheduling location-dependent queries clients cross cell bounderies in a multi-cell wireless environment. Our study is based on a common scenario where data objects are stationary while clients, which issue the queries, are mobile. For query processing, we use Voronoi Diagrams to construct an index and a semantic cache for improving data reusability. For handoff clients, we propose three scheduling methods, namely, the priority method, the intelligent method, and the hybrid method to improve performance. A simulation is conducted to study the performance of the methods.
Economic dynamics of agents in multiple auctions
Authors: Chris Preist, Andrew Byde, Claudio Bartolini
Venue: Proceedings of the fifth international conference on Autonomous agents (2001)

Over the last few years, electronic auctions have become an increasingly important aspect of e- commerce, both in the business to business and business to consumer domains. As a result of this, it is often possible to find many auctions selling similar goods on the web. However, when an individual is attempting to purchase such a good, they will usually bid in one, or a small number, of such auctions. This results in two forms of inefficiency. Firstly, the individual may pay more for the good than would be expected in an ideal market. Secondly, some sellers may fail to make a sale that could take place in an ideal market. In this paper, we present an agent that is able to participate in multiple auctions for a given good, placing bids appropriately to secure the cheapest price. We present experiments to show; (i) Current auction markets on the web are inefficient, with trades taking place away from equilibrium price, and not all benefit from trade being extracted. (ii) Our agent is able to exploit these inefficiencies, resulting in it making higher profits than the simple strategy of bidding in a small number of auctions. (iii) As more participants use our agent, the market becomes more efficient. When all participants use the agent, all trades take place close to equilibrium price, and the market approaches ideal behaviour.
On the external storage fragmentation produced by first-fit and best-fit allocation strategies
Authors: John E. Shore
Venue: Communications of the ACM (1975)

Published comparisons of the external fragmentation produced by first-fit and best-fit memory allocation have not been consistent. Through simulation, a series of experiments were performed in order to obtain better data on the relative performance of first-fit and best-fit and a better understanding of the reasons underlying observed differences. The time-memory-product efficiencies of first-fit and best-fit were generally within 1 to 3 percent of each other. Except for small populations, the size of the request population had little effect on allocation efficiency. For exponential and hyperexponential distributions of requests, first-fit outperformed best-fit; but for normal and uniform distributions, and for exponential distributions distorted in various ways, best-fit out-performed first-fit. It is hypothesized that when first-fit outperforms best-fit, it does so because first-fit, by preferentially allocating toward one end of memory, encourages large blocks to grow at the other end. Sufficient contiguous space is thereby more likely to be available for relatively large requests. Results of simulation experiments supported this hypothesis and showed that the relative performance of first-fit and best-fit depends on the frequency of requests that are large compared to the average request. When the coefficient of variation of the request distribution is greater than or approximately equal to unity, first-fit outperformed best-fit.
An Ada interface to lego mindstorms
Authors: Barry Fagin
Venue: ACM SIGAda Ada Letters (2000)

This article presents an Ada interface to the Lego MindstormsTM RCX "brick", the core element of a commercial product that emerged from a collaboration between the Lego Corporation and MIT's Media Laboratory. Since its arrival on the market in 1998, it has considerable interest in the computing community: a variety of operating systems and language interfaces are available for it, all provided free of charge by people who simply wanted to find out how the RCX workedThe interface described here is in use at the Air Force Academy as part of an experiment in computer science education. Students with no prior programming background are given a pre-built Mindstorms robot and a series of programming challenges, which they then attempt to implement using Ada. Our hope is that the experience of programming robots will provide an effective, efficient, and enjoyable method for conveying essential computer science concepts. We are currently attempting to assess its effectiveness, and hope to present our results at a future date.
The complexity of online groups: a case study of asynchronous collaboration
Venue: ACM Journal of Computer Documentation (JCD) (2001)

Work preparing documents is increasingly being done by diverse, geographically separated project teams. This essay describes some of the characteristics of such collaboration and applies them to a case study involving a team composing a mission statement. The group succeeded in their task, even though shortcomings inherent in asynchronous, distributed collaboration did lead to some problems.
An introduction to TCL/TK: the best language for introduction to computer science courses
Authors: Peter C. Isaacson
Venue: Proceedings of the second annual CCSC on Computing in Small Colleges Northwestern conference (2000)

This tutorial will present an introduction to the Tcl/Tk programming language which the instructor believes is the best language for Introduction to Computer Science courses. This hands-on experience will be organized around an introduction to Tcl/Tk, sample Tcl/Tk programs some of which were used in our Introduction to Computer Science course, and Tcl/Tk resources.
Symbolic Model Checking for Self-Stabilizing Algorithms
Authors: Tatsuhiro Tsuchiya, Shin'ichi Nagano, Rohayu Bt Paidi, Tohru Kikuno
Venue: IEEE Transactions on Parallel and Distributed Systems (2001)

A distributed system is said to be self-stabilizing if it converges to safe states regardless of its initial state. In this paper we present our results of using symbolic model checking to verify distributed algorithms against the self-stabilizing property. In general, the most difficult problem with model checking is state explosion; it is especially serious in verifying the self-stabilizing property, since it requires the examination of all possible initial states. So far applying model checking to self-stabilizing algorithms has not been successful due to the problem of state explosion. In order to overcome this difficulty, we propose to use symbolic model checking for this purpose. Symbolic model checking is a verification method which uses Ordered Binary Decision Diagrams (OBDDs) to compactly represent state spaces. Unlike other model checking techniques, this method has the advantage that most of its computations do not depend on the initial states. We show how to verify the correctness of algorithms by means of SMV, a well-known symbolic model checker. By applying the proposed approach to several algorithms in the literature, we demonstrate empirically that the state spaces of self-stabilizing algorithms can be represented by OBDDs very efficiently. Through these case studies, we also demonstrate the usefulness of the proposed approach in detecting errors.
Methods of evaluating polynomial approximations in function evaluation routines
Authors: C. T. Fike
Venue: Communications of the ACM (1967)

The method of nested multiplication is commonly used in function evaluation routines to evaluate approximation polynomials. New polynomial evaluation methods have been developed in recent years which require fewer multiplications than nested multiplication and may therefore be preferable for use in function evaluation routines. Although some of these methods do not appear to be practically useful because of rounding-error difficulties, several methods of evaluating low-degree polynomials have been found to be satisfactory. Three such methods are described and illustrated.
The electronics industry supply chain (panel session): who does what?
Authors: Rita Glover, Marc Halpern, Rick Becks, Richard Kubin, Henry Jurgens, Rich Cassidy, Ted Vucurevich
Venue: Proceedings of the 38th annual Design Automation Conference (2001)

The makeup and relationships within the design supply chain are changing rapidly. One-stop shopping, whereby a system house procures most of its design and fabrication services from a single source, is now being supplanted by a host of outsourcing suppliers. These players are developing online integration plat-forms for outsourced design engineering, business transactions, and data management.This evolution is being felt by the entire design automation industry, whether it be focused on the electronic design of chips, boards, or systems, or even the mechanical design of their packaging and housing. What are the implications of this trend on cost, demand for services, and time to market? How can all parties ride this wave of the future to achieve the best outcome in terms of collaborative design capabilities and quality of results?
A Smart Sensor Integrated Circuit for NASA's New Millennium Spacecraft
Authors: Nikolaos P. Paschalidis
Venue: Analog Integrated Circuits and Signal Processing (2001)

The modern space era can greatly benefit from the rapidly growing microelectronics technologies in order to enable the ambitious exploratory and commercial space endeavors of the new millennium. A smart sensor, analog/digital, integrated circuit, suitable for spacecraft avionics data acquisition and control is presented. The Remote Input/Output (RIO) device is developed by The Johns Hopkins University/Applied Physics Laboratory, for NASA's Jet Propulsion Laboratory, to support many oncoming new millennium space missions. TRIO&mdash;the first version of RIO&mdash;is designed to interface to temperature, pressure, total radiation dose sensors, and generally to voltage/current transducers. The microchip includes front-end conditioning circuitry, an ADC, memory, serial and CPU interface, and a digital port. Furthermore the device is developed to meet extreme space qualification specifications such as radiation effects. This versatile system-on-a-chip device is becoming a key enabling technology for new-generation NASA and Commercial spacecraft systems. Missions that are intended to use the TRIO device are the: Europa Orbiter, Deep Space 4, Solar Probe, Pluto Express, Mars Sample Return, Stereo, Contour, etc.
Sink-insertion for mesh improvement
Authors: Herbert Edelsbrunner, Damrong Guoy
Venue: Proceedings of the seventeenth annual symposium on Computational geometry (2001)

We propose sink-insertion as a new technique to improve the mesh quali ty of Delaunay triangulations. We compare it with the conventional circumcenter-insertion technique under three scheduling regimes: incremental, in blocks, and in parallel. Justification for sink-insertion is given in terms of mesh quality, numerical robustness, running time, and ease of parallelization.
Providing presence cues to telephone users
Authors: Allen E. Milewski, Thomas M. Smith
Venue: Proceedings of the 2000 ACM conference on Computer supported cooperative work (2000)

A significant problem with telephone communication is that callers do not have enough awareness about the Personal Presence of people they want to call. The result can be unwanted, interrupting calls. Thelive addressbookis an application that helps users make more informed telephone calls and teleconferences, from anywhere, via their wireless PDA or desktop browser. Unlike other network-based address books, which maintain static information, the live addressbook can display dynamic information about where the recipient currently is (i.e., reach number), and how available he/she currently is for calls. The system accomplishes this by applying to telephony the "Buddy List" concepts made popular in Instant Messaging applications. User trials assess the applicability of Personal Presence information in a telephone context.
On a Hopfield Net Arising in the Modelling and Control of Over-Saturated Signalized Intersections
Authors: Fatine Maghrebi
Venue: Neural Processing Letters (1999)

We present a neural method &ndash; based on the Hopfield net &ndash; for the modelling and control of over-saturated signalized intersections. The problem is to look, in real-time, for lights signal setting which minimize a given traffic criterion such as waiting time. The use of the Hopfield model is straightforward justified by its optimization capabilities, especially its fast time computing (by its own dynamic), which is of a great interest in real-time problems like the traffic control one. The original Hopfield algorithm is modified to take into account proper constraints of the traffic problem. This approach is illustrated by numerical examples of traffic conditions generated by a simulator. We extend the method to urban nets of several interconnected intersections.
Clone join and shadow join: two parallel spatial join algorithms
Authors: Jignesh M. Patel, David J. DeWitt
Venue: Proceedings of the 8th ACM international symposium on Advances in geographic information systems (2000)

Spatial applications frequently need to join two data sets based on some spatial relationship between objects in the two data sets. This operation, called a spatial join, is an expensive operation and in the past many algorithms have been proposed for evaluating the spatial join operation on a single processor system. However, the use of parallelism for handling queries involving large volumes of spatial data has received little attention. In this paper, we explore the use of parallelism for evaluating the spatial join operation. We first propose two strategies for storing spatial data in a parallel database system. We propose a number of spatial join algorithms based on these declustering strategies. Two algorithms are identified as the key algorithms in this design space. We analyze these two algorithms both analytically and experimentally. The experimental evaluation uses real data sets and is based on an actual implementation in a parallel database system. The experiments show that both algorithms can effectively exploit parallelism.
An Efficient Buffer Memory System for Subarray Access
Authors: Jong Won Park
Venue: IEEE Transactions on Parallel and Distributed Systems (2001)

Many current graphical display systems utilize a buffer memory system to contain a two-dimensional image array to be modified and displayed. In order to speed up the update of the buffer memory system, it is required that the buffer memory system accesses many image points within an image subarray in parallel. This paper proposes an efficient buffer memory system for a fast and high-resolution graphical display system. The memory system provides parallel accesses to $pq$ image points within a ${\rm{block(p \times q)}}$, a ${\rm{horizontal(1 \times pq)}}$, a ${\rm{vertical(pq \times 1)}}$, a forward-diagonal, or a backward-diagonal subarray in a two-dimensional image array, ${\rm{M \times N}}$, where the design parameters $p$ and $q$ are all powers of two. In the address calculation and routing circuit of the proposed buffer memory system, the address differences of the five subarrays are prearranged according to the index numbers of memory modules and stored in two Static Random Access Memories (SRAMs), so that the address differences are simply added to the base address to obtain the addresses according to the index numbers of memory modules. In addition, for the fast address calculation, one single multiplication operation in the base address calculation is replaced by a SRAM access, so that the multiplication operation can be performed during the SRAM access for the address differences for the case when N is not a power of two. The address calculation and routing circuit proposed in this paper is improved in the hardware cost, the complexity of control, and the speed over the previous circuits.
A mechanism to detect changing access patterns and automatically migrate distributed R-tree indexed multidimensional data
Authors: Scott T. Leutenegger, Rostislav M. Sheykhet, Mario A. López
Venue: Proceedings of the 8th ACM international symposium on Advances in geographic information systems (2000)

We present an algorithm to migrate multidimensional data in a non-replicated distributed environment. Our proposed algorithm is intented to improve query performance for mobile objects. Our algorithm automatically detects access pattern changes and migrates portions of the data from current sites of residence to sites recently accessing the data most frequently, thus reducing remote communication costs. We assume the data is indexed by an R-tree multidimensional index and that a global R-tree is used to locate and retrieve portions of the data set. We present a distributed R-tree structure and experimentally explore a specific access detection and migration mechanism. Our experimental results show that when compared to the no-migration case, and depending on network speed, our migration scheme may result in a query time reduction of a few percent to an order of magnitude.