ppxscal/embedding_network huggingface dataset:
An improved response surface methodology algorithm with an application to traffic signal optimization for urban networks
Authors: Shirish S. Joshi, Ajay K. Rathi, Jeffrey D. Tew
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Illustrates the use of the simulation-optimization technique of response surface methodology (RSM) in traffic signal optimization of urban networks. It also quantifies the gains of using the common random number (CRN) variance reduction strategy in such an optimization procedure. An enhanced RSM algorithm which employs conjugate gradient search techniques and successive second-order models is presented instead of the conventional approach. An illustrative example using an urban traffic network exhibits the superiority of using the CRN strategy over direct simulation in performing traffic signal optimization. The relative performance of the two strategies is quantified with computational results using the total network-wide delay as the measure of effectiveness.
Non-Markovian Petri nets
Authors: Kishor S. Trivedi, A. Bobbio, G. Ciardo, R. German, A. Puliafito, M. Telek
Venue: ACM SIGMETRICS Performance Evaluation Review (1995)

Non-Markovian models allow us to capture a very wide range of circumstances in which it is necessary to model phenomena whose times to occurrence is not exponentially distributed. Events such as timeouts in a protocol, service times at a machine performing the same task on each part, and memory access or instruction execution in a low-level h/w or s/w model, have durations which are constant or with a very low variance. Phase-type distributions can be used to approximate a non-exponential, but they increase the size of the state space.The analysis of stochastic systems with non-exponential timing is of increasing interest in the literature and requires the development of suitable modeling tools. Recently, some effort has been devoted to generalize the concept of Stochastic Petri Nets (SPN), by allowing the firing times to be generally distributed.A particular case of non-Markovian SPN, is the class of Deterministic and SPN (DSPN) [1]. A DSPN is a non-Markovian SPN where, in each marking, at most one transition is allowed to have a deterministic firing time with enabling memory policy.A new class of stochastic Petri nets has recently been defined [2, 3] by generalizing the deterministic firing times of the DSPN to generally distributed firing times. The underlying stochastic process for these classes of Petri nets is a Markov Regenerative Process (MRGP). This observation has opened a very fertile line of research aimed at the definition of solvable classes of models whose underlying marking process is an MRGP, and therefore referred to as Markov Regenerative Stochastic Petri Nets (MRSPN).Some of the results in this filed will be described in the session. In particular, Ciardo investigates stochastic confusion by defining the selection probability for transitions attempting to fire at the same time. German introduces the "method of supplementary variables" for the derivation of state equations describing the transient behavior of the marking process. Puliafito describes how, under some constraints, concurrent enabling of several generally distributed timed transitions is allowed. Bobbio and Telek discuss how age memory policy can be included to capture preemptive mechanisms of the resume (prs) type.
Relative Affine Structure: Canonical Model for 3D From 2D Geometry and Applications
Authors: Amnon Shashua, Nassir Navab
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1996)

We propose an affine framework for perspective views, captured by a single extremely simple equation based on a viewer-centered invariant we call relative affine structure. Via a number of corollaries of our main results we show that our framework unifies previous work¿including Euclidean, projective and affine¿in a natural and simple way, and introduces new, extremely simple, algorithms for the tasks of reconstruction from multiple views, recognition by alignment, and certain image coding applications.
Perturbed Optimization in Banach Spaces III: Semi-infinite Optimization
Authors: J. Frédéric Bonnans, Roberto Cominetti
Venue: SIAM Journal on Control and Optimization (1996)

This paper is devoted to the study of perturbed semi-infinite optimization problems, i.e., minimization over $\er^n$ with an infinite number of inequality constraints. We obtain the second-order expansion of the optimal value function and the first-order expansion of approximate optimal solutions in two cases: (i) when the number of binding constraints is finite and (ii) when the inequality constraints are parametrized by a real scalar. These results are partly obtained by specializing the sensitivity theory for perturbed optimization developed in part I (cf.\ [SIAM J. Control Optim., 34 (1996), pp. 1151--1171]) and deriving specific sharp lower estimates for the optimal value function which take into account the curvature of the positive cone in the space $C(\Omega)$ of continuous real-valued functions.
On the performance of pure adaptive search
Authors: Bruce W. Schmeiser, Jin Wang
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Studies the pure adaptive search (PAS), an iterative optimization algorithm whose next solution is chosen to be uniformly distributed over the set of feasible solutions that are no worse than the current solution. We extend the results of Patel, Smith and Zabinsky (1988) and Zabinsky and Smith (1992). In particular, we (1) show that PAS converges to the optimal solution almost certainly, (2) show that each PAS iteration reduces the expected remaining feasible-region volume by 50%, and (3) improve the Patel, Smith and Zabinsky complexity measure for convex problems.
The measured performance of personal computer operating systems
Authors: J. Bradley Chen, Yasuhiro Endo, Kee Chan, David Mazières, Antonio Dias, Margo Seltzer, Michael D. Smith
Venue: ACM Transactions on Computer Systems (TOCS) (1996)

This article presents a comparative study of the performance of three operating systems that run on the personal computer architecture derived form the IBM-PC. The operating systems, Windows for Workgroups, Windows NT, and NetBSD (a freely available variant of the UNIX operating system), cover a broad range of system functionality and user requirements, from a single-address-space model to full protection with preemptive multitasking. Our measurements are enable by hardware counters in Intel's Pentium processor that permit measurement of a broad range of processor events including instruction counts and on-chip cache miss counts. We use both microbenchmarks, which expose specific difference between the systems, and application workloads, which provide an indication of expected end-to-end performance. Our microbenchmark results show that accessing system functionality is often more expensive in Windows for Workgroups than in the other two systems due to frequent changes in machine mode and the use of system call hooks. When running native applications, Windows NT is more efficient than Windows, but it incurs overhead similar to that of a microkernel, since its application interface (the Win32 API) is implemented as a user-level server. Overall, system functionality can be accessed most efficiently in NetBSD; we attribute this to its monolithic structure and to the absence of the complications created by hardware backward-compatibility requirements in the other systems. Measurements of application performance show that although the impact of these differences is significant in terms of instruction counts and other hardware events (often a factor of 2 to 7 difference between the systems), overall performance is sometimes determined by the functionality provided by specific subsystems, such as the graphics subsystem or the file system buffer cache.
Software trustability analysis
Authors: W. E. Howden, Yudong Huang
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (1995)

A measure of software dependability called trustability is described. A program p has trustability T if we are at least T confident that p is free of faults. Trustability measurement depends on detectability. The detectability of a method is the probability that it will detect faults, when there are faults present. Detectability research can be used to characterize conditions under which one testing and analysis method is more effective than another. Several detectability results that were only previously described informally, and illustrated by example, are proved. Several new detectability results are also proved. The trustability model characterizes the kind of information that is needed to justify a given level of trustability. When the required information is available, the trustability approach can be used to determine strategies in which methods are combined for maximum effectiveness. It can be used to determine the minimum amount of resources needed to guarantee a required degree of trustability, and the maximum trustability that is achievable with a given amount of resources. Theorems proving several optimization results are given. Applications of the trustability model are discussed. Methods for the derivation of detectability factors, the relationship between trustability and operational reliability, and the relationship between the software development process and trustability are described.
Analysis of balanced fork-join queueing networks
Authors: Elizabeth Varki, Lawrence W. Dowdy
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

This paper presents an analysis of closed, balanced, fork-join queueing networks with exponential service time distributions. The fork-join queue is mapped onto two non-parallel networks, namely, a serial-join model and a state-dependent model. Using these models, it is proven that the proportion of the number of jobs in the different subsystems of the fork-join queueing network remains constant, irrespective of the multiprogramming level. This property of balanced fork-join networks is used to compute quick, inexpensive bounds for arbitrary fork-join networks.
Simulated annealing: past, present, and future
Authors: Mark Fleischer
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper provides an overview of the simulated annealing algorithm and describes its historical foundation in thermodynamics as well as the genesis and evolution for solving difficult optimization problems. An example illustrating its application to graph problems is provided as well as a look at ongoing, state-of-the-art research using SA.
Effectiveness of global event queues in rollback reduction and load balancing
Authors: Sushil K. Prasad, Basem Naqib
Venue: ACM SIGSIM Simulation Digest (1995)

Compared to highly optimized optimistic simulators which use local event queues for individual processors on a shared-memory computer, we demonstrate that employing a single global event queue drastically reduces the number of rollbacks, brings down the storage requirements, and achieves superior load balance. On a bus-based Silicon Graphics multiprocessor, these virtues consistently translated into faster execution times and higher speedups on those synthetic networks of medium- to coarse-grained logical processes which were ridden with rollbacks and load imbalance on local-queue-based simulators. A dynamic randomization-based load distribution scheme for local-event-queue simulators is also shown to be an effective improvement.
Using Generative Models for Handwritten Digit Recognition
Authors: Michael Revow, Christopher K. I. Williams, Geoffrey E. Hinton
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1996)

We describe a method of recognizing handwritten digits by fitting generative models that are built from deformable B-splines with Gaussian "ink generators" spaced along the length of the spline. The splines are adjusted using a novel elastic matching procedure based on the Expectation Maximization (EM) algorithm that maximizes the likelihood of the model generating the data. This approach has many advantages. 1) After identifying the model most likely to have generated the data, the system not only produces a classification of the digit but also a rich description of the instantiation parameters which can yield information such as the writing style. 2) During the process of explaining the image, generative models can perform recognition driven segmentation. 3) The method involves a relatively small number of parameters and hence training is relatively easy and fast. 4) Unlike many other recognition schemes, it does not rely on some form of pre-normalization of input images, but can handle arbitrary scalings, translations and a limited degree of image rotation. We have demonstrated our method of fitting models to images does not get trapped in poor local minima. The main disadvantage of the method is it requires much more computation than more standard OCR techniques.
Business process reengineering: examining some major roadblocks to increased self-control for the employee
Authors: Jon Iden
Venue: Proceedings of conference on Organizational computing systems (1995)

This paper explores the meaning of the concept of self-control in the context of Business Process Reengineering (BPR). BPR is a radical approach that breaks with many conventional ideas from applied management and organization theory. The delegation of control and decision-authority is a key concept within BPR, and reengineering advocates argue that employees should control themselves. Self-controlled employees represents a radical shift from what could be considered as 'status quo', and it will certainly be a challenge to implement this. This paper examines some major roadblocks that might reduce the likelihood for self-control to be realized in the context of BPR.
Control of initialization bias in queueing simulations using queueing approximations
Authors: Manuel D. Rossetti, Patrick J. Delaney
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Investigates the use of analytical queueing approximations to assist in mitigating the effects of the initial transient period in steady-state GI/G/m queueing simulations. We investigate using queueing approximations to stochastically set the initial conditions of the simulation and we develop a new set of truncation heuristics based on GI/G/m queueing approximations. The new truncation heuristics are based on finding the truncation point in the simulation sample path which minimizes the mean squared error of the point estimator. Given that an approximation can be found, our methodology reduces the need for pilot runs and can easily be incorporated into a simulation, with significant results. We present the performance of the heuristics for replication deletion. The adaption to batch means is discussed. The result of our methodology is a less biased and less variable estimator of the expected wait time in the queue. We used the Extend simulation package for this research on a Macintosh Quadra 840AV.
Context constraints for compositional reachability analysis
Authors: Shing Chi Cheung, Jeff Kramer
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (1996)

Behavior analysis of complex distributed systems has led to the search for enhanced reachability analysis techniques which support modularity and which control the state explosion problem. While modularity has been achieved, state explosion in still a problem. Indeed, this problem may even be exacerbated, as a locally minimized subsystem may contain many states and transitions forbidden by its environment or context. Context constraints, specified as interface processes, are restrictions imposed by the environment on subsystem behavior. Recent research has suggested that the state explosion problem can be effectively controlled if context constraints are incorporated in compositional reachability analysis (CRA). Although theoretically very promising, the approach has rarely been used in practice because it generally requires a more complex computational model and does not contain a mechanism to derive context constraints automatically. This article presents a technique to automate the approach while using a similar computational model to that of CRA. Context constraints are derived automatically, based on a set of sufficient conditions for these constraints to be transparently included when building reachability graphs. As a result, the global reachability graph generated using the derived constraints is shown to be observationally equivalent to that generated by CRA without the inclusion of context constraints. Constraints can also be specified explicitly by users, based on their application knowledge. Erroneous constraints which contravene transparency can be identified together with an indication of the error sources. User-specified constraints can be combined with those generated automatically. The technique is illustrated using a clients/server system and other examples.
An object-oriented simulation model for communication network traffic at a general mail facility
Authors: Duane L. Setterdahl, Wayne J. Davis, Joseph G. Macro, Edward Barkmeyer
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper discusses an object-oriented simulation project conducted for the United States Postal System (USPS) to test the reliability of an Ethernet LAN to support communication among various equipment contained at a General Mail Facility. The study was authorized by the National Institute of Standards and Technology to verify that the communication requirements derived from the implementation of their developed Postal Equipment Management System would not saturate the communication network. The simulated network handles over 400 transactions per second, and the USPS specified that eight hours of operation (one shift) must be simulated. The simulation was programmed in C++, and the completed study demonstrated that an Ethernet LAN can reliably support the communication requirements.
Algorithm 751: TRIPACK: a constrained two-dimensional Delaunay triangulation package
Authors: R. J. Renka
Venue: ACM Transactions on Mathematical Software (TOMS) (1996)

TRIPACK is a Fortran 77 software package that employs an incremental algorithm to construct a constrained Delaunay traingulation of a set of points in the plane (nodes). The triangulation covers the convex hull of the nodes but may include polygonal constraint regions whose triangles are distinguishable from those in the remainder of the triangulation. This effectively allows for a nonconvex or multiply connected triangulation (the complement of the union of constraint regions) while retaining the efficiency of searching and updating a convex triangulation. The package provides a wide range of capabilities including an efficient means of updating the triangulation with nodal additions or deletions. For N nodes, the storage requirement is 13N integer storage locations in addition to the 2N nodal coordinates.
Generalized Partially-Mixed-Polarity Reed-Muller Expansion and Its Fast Computation
Authors: Haomin Wu, M. A. Perkowski, Xiaoqiang Zeng, Nan Zhuang
Venue: IEEE Transactions on Computers (1996)

Generalized Partially-Mixed-Polarity Reed-Muller (GPMPRM) expansion, a canonical subfamily of Exclusive Sum of Products (ESOP), is presented. An efficient algorithm in two-dimensional data flow is proposed for computation of the GPMPRM forms. MCNC benchmark experimental results show that the minimal GPMPRM forms of these functions, on the average, have similar number of terms to their Sum of Products (SOP) counterparts while there are many functions for which the GPMPRM circuits are much smaller.
Simulation as a planning and scheduling tool for flexible manufacturing systems
Authors: Gleen R. Drake, Jeffrey S. Smith, Brett A. Peters
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper describes a flexible simulation technique which facilitates automated experimentation of different scheduling rules. An enhanced version of Arena/SIMAN is used to develop an extremely high fidelity model of the manufacturing system. The decision making of an FMS is characterized and a framework for simulation-based scheduling and control is also introduced.
Multicast and multiprotocol support for ATM based Internets
Authors: G. J. Armitage
Venue: ACM SIGCOMM Computer Communication Review (1995)

Both the Internet Engineering Task Force (IETF) and ATM Forum are addressing the issue of building higher layer networks using ATM. The IETF's focus is on IP, while the ATM Forum has expanded its vision to include all common Network layer protocols. The task faced by both organizations is to develop solutions that will cause minimal interoperability problems, both for users and network architects.This paper focuses on the solutions coming out of the IETF's IP over ATM working group, including the author's proposal for flexible, high performance IP multicast over ATM. The emerging Next Hop Resolution Protocol from the IETF's Routing Over Large Cloud group is briefly examined, and its possible conflict with the ATM Forum's Multiprotocol Over ATM'work is also discussed. The author finishes by noting how current IETF work could support 'multiprotocol' networks.
Performance and Scalability of Preconditioned Conjugate Gradient Methods on Parallel Computers
Authors: Anshul Gupta, Vipin Kumar, Ahmed Sameh
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

This paper analyzes the performance and scalability of an iteration of the preconditioned conjugate gradient algorithm on parallel architectures with a variety of interconnection networks, such as the mesh, the hypercube, and that of the CM-5¿* parallel computer. It is shown that for block-tridiagonal matrices resulting from two-dimensional finite difference grids, the communication overhead due to vector inner products dominates the communication overheads of the remainder of the computation on a large number of processors. However, with a suitable mapping, the parallel formulation of a PCG iteration is highly scalable for such matrices on a machine like the CM-5 whose fast control network practically eliminates the overheads due to inner product computation. The use of the truncated Incomplete Cholesky (IC) preconditioner can lead to further improvement in scalability on the CM-5 by a constant factor. As a result, a parallel formulation of the PCG algorithm with IC preconditioner may execute faster than that with a simple diagonal preconditioner even if the latter runs faster in a serial implementation. For the matrices resulting from three-dimensional finite difference grids, the scalability is quite good on a hypercube or the CM-5, but not as good on a 2-D mesh architecture. In the case of unstructured sparse matrices with a constant number of nonzero elements in each row, the parallel formulation of the PCG iteration is unscalable on any message passing parallel architecture, unless some ordering is applied on the sparse matrix. The parallel system can be made scalable either if, after reordering, the nonzero elements of the $N\times N$ matrix can be confined in a band whose width is $O(N^y)$ for any $y\char'74 1$, or if the number of nonzero elements per row increases as $N^x$ for any $x > 0$. Scalability increases as the number of nonzero elements per row is increased and/or the width of the band containing these elements is reduced. For unstructured sparse matrices, the scalability is asymptotically the same for all architectures. Many of these analytical results are experimentally verified on the CM-5 parallel computer.