ppxscal/embedding_network huggingface dataset:
Stabilization by Constrained Controls
Authors: Georgi V. Smirnov
Venue: SIAM Journal on Control and Optimization (1996)

A stabilization problem for a general nonlinear control system is considered. In particular the control corresponding to the equilibrium position may belong to the boundary of the control set. A linear control system is considered as a first approximation for the original problem. The right-hand side of the linear system generates a set-valued map of a special type known as a convex process. This set-valued map has a number of properties similar to those of a linear operator. They allow one to establish necessary and sufficient conditions for solvability of the regulator design problem for the first approximation and to construct a Lyapunov function. Based on these results the nonlinear stabilization problem is investigated. Different statements of the regulator design problem are studied. Stabilization problems for some mechanical systems are considered to illustrate the regulator design techniques. The properties of transient characteristics (the ``peak'' effect) are discussed for a linear stabilization problem under controllability conditions.
Design of Efficient Regular Arrays for Matrix Multiplication by Two-Step Regularization
Authors: Jong-Chuang Tsay, Pen-Yuang Chang
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

A two-step regularization method in which first permutation sequences and then broadcast planes are selected is proposed to design various regular iterative algorithms for matrix multiplication. The regular iterative algorithms are then spacetime mapped to regular arrays, such as mesh, cylindrical, two-layered mesh, and orbital arrays. The proposed method can be used to design regular arrays with execution time of less than $N$ (problem size).Index Terms¿Broadcast, cylindrical array, mesh array, orbital array, parallel algorithm design, permutation sequence, propagation, two-layered mesh array, VLSI architecture
Where Do Operations Come From? A Multiparadigm Specification Technique
Authors: Pamela Zave, Michael Jackson
Venue: IEEE Transactions on Software Engineering (1996)

We propose a technique to help people organize and write complex specifications, exploiting the best features of several different specification languages. Z is supplemented, primarily with automata and grammars, to provide a rigorous and systematic mapping from input stimuli to convenient operations and arguments for the Z specification. Consistency analysis of the resulting specificaiton is based on the structural rules. The technique is illustrated by two examples, a graphical human-computer interface and a telecommunications system.
Migration of processes, files, and virtual devices in the MDX operating system
Authors: Harald Schrimpf
Venue: ACM SIGOPS Operating Systems Review (1995)

Load management in distributed systems is usually focused on balancing process execution and communication load. Stress on storage media and I/O-devices is considered only indirectly or disregarded. For I/O-intensive processes this imposes severe restrictions on balancing algorithms: processes have to be placed relative to fixed allocated resources. Therefore, beyond process migration, there is a need for a migration of all operating system objects, like files, pipes, timers, virtual terminals, and print jobs. In addition to new options for balancing cpu loads, this also makes it possible to balance the loads associated with these objects like storage capacity or I/O-bandwidth.This paper presents a concept for a general migration of nearly all operating system objects of a UNIX environment. The migrations of these objects work all in the same UNIX compliant and transparent manner. Objects can be moved throughout a distributed system independently of each other and at any time, according to a user defined policy. The migration mechanism is implemented as part of the MDX operating system; we present performance measurements. We believe that most of the mechanism can also apply to other message-passing based distributed operating systems.
Efficient exploration of availability models guided by failure distances
Authors: Juan A. Carrasco, Javier Escribá, Angel Calderón
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

Recently, a method to bound the steady-state availability using the failure distance concept has been proposed. In this paper we refine that method by introducing state space exploration techniques. In the methods proposed here, the state space is incrementally generated based on the contributions to the steady-state availability band of the states in the frontier of the currently generated state space. Several state space exploration algorithms are evaluated in terms of bounds quality and memory and CPU time requirements. The more efficient seems to be a waved algorithm which expands transition groups. We compare our new methods with the method based on the failure distance concept without state exploration and a method proposed by Souza e Silva and Ochoa which uses state space exploration but does not use the failure distance concept. Using typical examples we show that the methods proposed here can be significantly more efficient than any of the previous methods.
Resource Placement with Multiple Adjacency Constraints in k-ary n-Cubes
Authors: Parameswaran Ramanathan, Suresh Chalasani
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

The problem of placing resources in a $k$-ary $n$-cube $(k\,{\char'076}\,2)$ is considered in this paper. For a given $j \geq 1,$ resources are placed such that each nonresource node is adjacent to $j$ resource nodes. We first prove that perfect $j$-adjacency placements are impossible in $k$-ary $n$-cubes if $n\,{\char'074}\,j\,{\char'074}\,2n.$ Then, we show that a perfect $j$-adjacency placement is possible in $k$-ary $n$-cubes when one of the following two conditions is satisfied: 1) if and only if $j$ equals $2n$ and $k$ is even, or 2) if $1 \leq j \leq n$ and there exist integers $q$ and $r$ such that $q$ divides $k$ and $q^r - 1 = 2n/j.$ In each case, we describe an algorithm to obtain perfect $j$-adjacency placements. We also show that these algorithms can be extended under certain conditions to place $j$ distinct types of resources in a such way that each nonresource node is adjacent to a resource node of each type. For the cases when perfect $j$-adjacency placements are not possible, we consider approximate $j$-adjacency placements. We show that the number of copies of resources required in this case either approaches a theoretical lower bound on the number of copies required for any $j$-adjacency placement or is within a constant factor of the theoretical lower bound for large $k.$Index Terms¿Resource allocation, multiprocessors, hypercubes, mesh connected computers, interconnection network, fault-tolerance.
Algorithm 655: IQPACK: FORTRAN subroutines for the weights of interpolatory quadratures
Authors: Sylvan Elhay, Jaroslav Kautsky
Venue: ACM Transactions on Mathematical Software (TOMS) (1987)

We present FORTRAN subroutines that implement the method described in [3] for the stable evaluation of the weights of interpolatory quadratures with prescribed simple or multiple knots. Given a set of knots and their multiplicities, the package generates the weights by using the zeroth moment &mgr;0 of w, the weight function in the integrand, and the (symmetric tridiagonal) Jacobi matrix J associated with the polynomials orthogonal on (a, b) with respect to w. There are utility routines that generate &mgr;0 and J for classical weight functions, but quadratures can be generated for any &mgr;0 and J supplied by the user. Utility routines are also provided that (1) evaluate a computed quadrature, applied to a user-supplied integrand, (2) check the polynomial order of precision of a quadrature formula, and (3) compute the knots and weights of simple Gaussian quadrature formula.
Security issues in a networked UNIX and MVS/VM environment
Authors: James J. Mavrikidis
Venue: ACM SIGSAC Review (1996)

This paper examines some security issues that arise from the interaction of different operating environments. The paper will focus on a particular network configuration involving two of IBM's Mainframe operating systems and an AT amp;T UNIX system. Each system along with the networking scheme used to connect these environments will be examined. The examined interaction will consist mostly of remote process execution. Each system will be described insofar as it relates to the security issues. A more detailed description of each operating environment can be found in the books in the reference section of this paper.
Minimizing the average cost of paging and registration: a timer-based method
Authors: C. Rose
Venue: Wireless Networks (1996)

Methods of balancing call registration and paging are developed in this paper. Given that the probability distribution on the user location as a function of time is either known or can be calculated, previous work shows the existence of lower bounds on the average cost of paging. Here these bounds are used in conjunction with a Poisson incoming-call arrival model to formulate the paging/registration optimization problem in terms of timeout parameters, $\tau _m$; the maximum amount of time to wait before registering given the last known location was $\tau _m$. Timer-based methods, as opposed to location-based methods, do not require the user to record and process location information during the time between location updates. This feature might be desirable for minimizing mobile transceiver use during idle periods. We then consider uniform motion processes where a spatial translation of starting location produces an identical spatial translation of the associated time-varying probability distribution. This leads to a universal timeout parameter $\tau $ which may be readily calculated. We study $\tau $ and the minimum cost of paging/registration for a simple model of user motion and compare our results to an earlier method of location-based paging/registration cost minimization.
Searching symbolically for Ape&acute;ry-like formulae for values of the Riemann zeta function
Authors: Jonathan Borwein, David Bradley
Venue: ACM SIGSAM Bulletin (1996)

We discuss some aspects of the search for identities using computer algebra and symbolic methods. To keep the discussion as concrete as possible, we shall focus on so-called Ap eacute;ry-like formulae for special values of the Riemann Zeta function. Many of these results are apparently new, and much more work needs to be done before they can be formally proved and properly classified. A first step in this direction can be found in [1].
Object on the server: are we ready? (panel)
Authors: Yen-Ping Shan, Tom Morgan, Phil Proudfoot, Jim Thompson, John Tibetts
Venue: Proceedings of the 11th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications (1996)

Object-oriented concepts such as reuse and encapsulation offer many benefits to application development, particularly in managing complexity and change. All the benefits of OO that apply to the client can apply equally well to the server. However, until recently, these concepts have proven to benefit only the client side. Could there be any intrinsic or conceptual reason for this? Or could it be a result of timing, the availability of the tools, and the conservative restraints that result from the mission-critical nature of server computing?This panel will explore the roles of objects on the server by examining the experiences of the panelists from a technology consumer's perspective. By doing so, we would like to provide insights for corporations that are making decisions on OO technology, point out pitfalls along the way, and identify potential opportunities for technology providers.All panelists have developed production level object servers. The panel will answer the question of whether we are ready for object servers by discussing the following issues: bull; Different server types: transactional server, data server, application server, web server, etc. Are they really that much different? Which one is the most important kind? bull; Experience in implementing and maintaining object systems on the server: the configurations of the systems and how they were arrived at; the tools and programming languages used. bull; Benefits and drawbacks of server object systems. bull; What's hard? What's easy? bull; What are the prerequisites for pervasive deployments of objects on the server? (e.g., standards, application types, customer situations, tools, and languages.) bull; What would be desirable for technology providers (researchers and vendors) to provide? (Tools, languages, execution environments that represents vendor opportunities.) bull; Practical advice to organizations interested in introducing objects to the server.
An array operation synthesis scheme to optimize Fortran 90 programs
Authors: Gwan-Hwan Hwang, Jenq Kuen Lee, Dz-Ching Ju
Venue: Proceedings of the fifth ACM SIGPLAN symposium on Principles and practice of parallel programming (1995)

An increasing number of programming languages, such as Fortran 90 and APL, are providing a rich set of intrinsic array functions and array expressions. These constructs which constitute an important part of data parallel languages provide excellent opportunities for compiler optimizations. In this paper, we present a new approach to combine consecutive data access patterns of array constructs into a composite access function to the source arrays. Our scheme is based on the composition of access functions, which is similar to a composition of mathematic functions. Our new scheme can handle not only data movements of arrays of different numbers of dimensions and segmented array operations but also masked array expressions and multiple sources array operations. As a result, our proposed scheme is the first synthesis scheme which can synthesize Fortran 90 RESHAPE, EOSHIFT, MERGE, and WHERE constructs together. Experimental results show speedups from 1.21 to 2.95 for code fragments from real applications on a Sequent multiprocessor machine by incorporating the proposed optimizations.
PC notes
Authors: Eugene Styer
Venue: ACM SIGICE Bulletin (1995)

In this third installment in the series, we will start looking at the internals of the 80x86 family. There are fourteen registers contained in the original 8088. The registers are listed below:See pdf for registers.
On the Stability of Cholesky Factorization For Symmetric Quasidefinite Systems
Authors: Philip E. Gill, Michael A. Saunders, Joseph R. Shinnerl
Venue: SIAM Journal on Matrix Analysis and Applications (1996)

Sparse linear equations $Kd=r$ are considered, where $K$ is a specially structured symmetric indefinite matrix that arises in numerical optimization and elsewhere. Under certain conditions, $K$ is quasidefinite. The Cholesky factorization $PKP^{T} = LDL^{T}$ is then known to exist for any permutation $P$, even though $D$ is indefinite. Quasidefinite matrices have been used successfully by Vanderbei within barrier methods for linear and quadratic programming. An advantage is that for a sequence of $K$'s, $P$ may be chosen once and for all to optimize the sparsity of $L$, as in the positive-definite case. A preliminary stability analysis is developed here. It is observed that a quasidefinite matrix is closely related to an unsymmetric positive-definite matrix, for which an $LDM^{T}$ factorization exists. Using the Golub and Van Loan analysis of the latter, conditions are derived under which Cholesky factorization is stable for quasidefinite systems. Some numerical results confirm the predictions.
BestFit, distribution fitting software by Palisade Corporation
Authors: Linda Jankauskas, Sam McLafferty
Venue: Proceedings of the 27th conference on Winter simulation (1995)

BestFit is distribution-fitting software for Microsoft Windows that finds the statistical distribution function that best fits a data set. BestFit provides a flexible, easy-to-use environment for analysis that allows users to focus on their data, not their software. Users of simulation software can use distributions produced by BestFit to define uncertainty in their simulation models. BestFit helps you find the best representation of randomness in your model, making your simulation results more accurate. Users of RISK, ProModel or any other simulation software will find BestFit an invaluable tool for defining uncertainty.
Change detection in hierarchically structured information
Authors: Sudarshan S. Chawathe, Anand Rajaraman, Hector Garcia-Molina, Jennifer Widom
Venue: Proceedings of the 1996 ACM SIGMOD international conference on Management of data (1996)

Detecting and representing changes to data is important for active databases, data warehousing, view maintenance, and version and configuration management. Most previous work in change management has dealt with flat-file and relational data; we focus on hierarchically structured data. Since in many cases changes must be computed from old and new versions of the data, we define the hierarchical change detection problem as the problem of finding a "minimum-cost edit script" that transforms one data tree to another, and we present efficient algorithms for computing such an edit script. Our algorithms make use of some key domain characteristics to achieve substantially better performance than previous, general-purpose algorithms. We study the performance of our algorithms both analytically and empirically, and we describe the application of our techniques to hierarchically structured documents.
SIMPROCESS III: object-oriented business process simulation
Authors: Jeffry Jones
Venue: Proceedings of the 27th conference on Winter simulation (1995)

SIMPROCESS III combines the principles of business process re-engineering, the power of simulation, and the clarity of animated graphics to help understand and predict the consequences of proposed changes to business systems. SIMPROCESS III is designed to answer questions quickly-with no programming. You pose a question, graphically configure a model, run the simulation, and reach conclusions. You then run the model with proposed changes to close in on the system configuration that best suits your needs. This paper describes who should use SIMPROCESS III, the types of systems SIMPROCESS III can model, and how a model is constructed.
Developing and deploying a corporate-wide digital signature capability
Authors: Diane E. Coe, Frank J. Smith
Venue: ACM SIGSAC Review (1995)

Some time ago, MITRE's Information Systems Architect produced a document identifying the architectural goals of The MITRE Corporation in terms of its information systems. In this document, the author described an electronic workplace where paper is virtually eliminated. Information is generated electronically, signed electronically, and routed for review, approval, and action all without ever appearing in printed form. In moving toward this goal architecture, MITRE has developed a digital signature capability that will be deployed throughout the Corporation during the third quarter of 1995. This digital signature capability, an integral component of the electronic workplace, will significantly reduce both the time and the money currently spent on generating and processing paper forms.
A comparison of system monitoring methods, passive network monitoring and kernel instrumentation
Authors: A. W. Moore, A. J. McGregor, J. W. Breen
Venue: ACM SIGOPS Operating Systems Review (1996)

This paper presents the comparison of two methods of system monitoring, passive network monitoring and kernel instrumentation. The comparison is made on the basis of passive network monitoring being used as a replacement for kernel instrumentation in some situations. Despite the fact that the passive network monitoring technique is shown to perform poorly as a direct replacement for kernel instrumentation, this paper indicates the areas where passive network monitoring could be used to the greatest advantage and presents methods by which the discrepancies between results of the two techniques could be minimised.
Properly rounded variable precision square root
Authors: T. E. Hull, A. Abrham
Venue: ACM Transactions on Mathematical Software (TOMS) (1985)

The square root function presented here returns a properly rounded approximation to the square root of its argument, or it raises an error condition if the argument is negative. Properly rounded means rounded to the nearest, or to nearest even in case of a tie. It is variable precision in that it is designed to return a p-digit approximation to a p-digit argument, for any p > 0. (Precision p means p decimal digits.) The program and the analysis are valid for all p > 0, but current implementations place some restrictions on p.
Distributed process groups in the V Kernel
Authors: David R. Cheriton, Willy Zwaenepoel
Venue: ACM Transactions on Computer Systems (TOCS) (1985)

The V kernel supports an abstraction of processes, with operations for interprocess communication, process management, and memory management. This abstraction is used as a software base for constructing distributed systems. As a distributed kernel, the V kernel makes intermachine boundaries largely transparent. In this environment of many cooperating processes on different machines, there are many logical groups of processes. Examples include the group of tile servers, a group of processes executing a particular job, and a group of processes executing a distributed parallel computation. In this paper we describe the extension of the V kernel to support process groups. Operations on groups include group interprocess communication, which provides an application-level abstraction of network multicast. Aspects of the implementation and performance, and initial experience with applications are discussed.
On the simultaneous construction of sample paths
Authors: Enver Yücesan, Sheldon H. Jacobson
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Sensitivity analysis and optimization within stochastic discrete event simulation require the ability to rapidly estimate performance measures under different parameter values. One technique, termed "rapid learning", aims at enumerating all possible sample paths under different parameter values of the model based on the observed sample path under the nominal parameter value. There are two necessary conditions for this capability: observability, which asserts that every state observed in the nominal path is always richer in terms of feasible events than the states observed in the constructed paths, and constructability, which, in addition to observability, requires that the lifetime of an event has the same distribution as its residual life. This paper asserts that the verification of the observability condition is an NP-hard search problem. This result, in turn, implies that it is algorithmically not possible to find parameter values satisfying observability; hence, it encourages the development of heuristic procedures. Further implications are also discussed.