ppxscal/embedding_network huggingface dataset:
A Duality Approach in the Optimization of Beams and Plates
Authors: J. Sprekels, D. Tiba
Venue: SIAM Journal on Control and Optimization (1999)

We introduce a class of nonlinear transformations called "resizing rules" which associate with optimal shape design problems certain equivalent distributed control problems while preserving the state of the system. This puts into evidence the duality principle that the class of system states that can be achieved, under a prescribed force, via modifications of the structure (shape) of the system can be obtained as well via the modifications of the force action, under a prescribed structure.We apply such transformations to the optimization of beams and plates, and in the simply supported or cantilevered cases, the obtained control problems are even convex. In all cases, we establish existence theorems for optimal pairs by assuming only boundedness conditions. Moreover, in the simply supported case, we also prove the uniqueness of the global minimizer. A general algorithm that iterates between the original transformed problems is introduced and studied. The applications also include the case of variational inequalities.
Process Innovation and Learning by Doing in Semiconductor Manufacturing
Authors: Nile W. Hatch, David C. Mowery
Venue: Management Science (1998)

This paper analyzes the relationship between process innovation and learning by doing in the semiconductor industry where improvements in manufacturing yield are a catalyst for dynamic cost reductions. In contrast to most previous studies of learning by doing, the learning curve is shown here to be the product of deliberate activities intended to improve yields and reduce costs, rather than the incidental byproduct of production volume. Since some of the knowledge acquired through learning by doing during new process development is specific to the production environment where the process is developed, some knowledge is effectively lost when a new process is transferred to manufacturing. We find that dedicated process development facilities, geographic proximity between development and manufacturing facilities, and the duplication of equipment between development and manufacturing facilities are all significant in improving performance in introducing new technologies. Once in manufacturing, new processes are shown to disrupt the ongoing learning activities of existing processes by drawing away scarce engineering resources to "debug" the new processes.
Design and Evaluation of System-Level Checks for On-Line Control Flow Error Detection
Authors: Z. Alkhalifa, V. S. S. Nair, N. Krishnamurthy, J. A. Abraham
Venue: IEEE Transactions on Parallel and Distributed Systems (1999)

This paper evaluates the concurrent error detection capabilities of system-level checks, using fault and error injection. The checks comprise application and system level mechanisms to detect control flow errors. We propose Enhanced Control-Flow Checking Using Assertions (ECCA). In ECCA, branch-free intervals (BFI) in a given high or intermediate level program are identified and the entry and exit points of the intervals are determined. BFIs are then grouped into blocks, the size of which is determined through a performance/overhead analysis. The blocks are then fortified with preinserted assertions. For the high level ECCA, we describe an implementation of ECCA through a preprocessor that will automatically insert the necessary assertions into the program. Then, we describe the intermediate implementation possible through modifications made on gcc to make it ECCA capable. The fault detection capabilities of the checks are evaluated both analytically and experimentally. Fault injection experiments are conducted using FERRARI [1] to determine the fault coverage of the proposed techniques.
Improving the design of interactive software
Authors: David F. Redmiles
Venue: ACM SIGSOFT Software Engineering Notes (2000)

This NSF sponsored CAREER project combines elements of research in human-computer interaction with research in software engineering. Three objectives are 1) to develop a model of software development as a process of on-going communication; 2) to support this model through active mechanisms in software tools; and 3) to improve the accessibility and acceptance of usability methods by software practitioners. In general, the objectives reflect a theory of human-centered software development.
The challenges and directions of MIS curriculum development in respect of transformation of business requirements
Authors: Stanislaw Wrycza, Thaddeus W. Usowicz, Andras Gabor, Borut Verber
Venue: ACM SIGCSE Bulletin (1999)

Effective use of information technology (IT), is becoming one of the prime determinants of success of business organization. However, rapid advances in IT cause that knowledge and skills required by IS professionals have to be changed continuously and profoundly. In this environment, IS/IT skills can become obsolete quite easily. The IS/IT jobs of tomorrow will require the flexible updating of knowledge, skills and abilities for effective performance of changing tasks and duties.
Interacting with eye movements in virtual environments
Authors: Vildan Tanriverdi, Robert J. K. Jacob
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

Eye movement-based interaction offers the potential of easy, natural, and fast ways of interacting in virtual environments. However, there is little empirical evidence about the advantages or disadvantages of this approach. We developed a new interaction technique for eye movement interaction in a virtual environment and compared it to more conventional 3-D pointing. We conducted an experiment to compare performance of the two interaction types and to assess their impacts on spatial memory of subjects and to explore subjects' satisfaction with the two types of interactions. We found that the eye movement-based interaction was faster than pointing, especially for distant objects. However, subjects' ability to recall spatial information was weaker in the eye condition than the pointing one. Subjects reported equal satisfaction with both types of interactions, despite the technology limitations of current eye tracking equipment.
Issues of online research repositories from the perspective of the biomedical sciences
Authors: David L. Armbruster
Venue: ACM Journal of Computer Documentation (JCD) (2000)

This commentary on Joseph Y. Halperns proposal for a computing research repository discusses difference in traditions and practices of online publishing and repositories between computing and biomedicals ciences. Issues of accessibility and archiving are also discussed.
Partitioning Analog and Digital Processing in Mixed-Signal Systems
Authors: Sydney Reader, Won Namgoong, Teresa Meng
Venue: Journal of VLSI Signal Processing Systems (2000)

Shrinking feature sizes, combined with the need for low-power and lightweight components, fuel the desire to place large mixed-signal systems onto a single die. A major design issue in mixed-signal systems is the effect of digital switching noise coupled to sensitive analog circuits through the substrate. A method is presented for minimizing this effect by partitioning digital and analog processing into separate time blocks. The resulting trade-off between lost signal and increased energy consumption is explored. As an example, a GPS synchronizer design is analyzed with respect to modifications that can be made to increase performance, while minimizing any associated energy penalty. Application of the partitioning method to other communications systems is discussed.
A Method for Computing the 2-D Stability Margin Based ona New Stability Test for 2-D Systems
Authors: Nikos E. Mastorakis
Venue: Multidimensional Systems and Signal Processing (1999)

In this paper, a new method to compute the stability margin of 2-D (two-dimensional) discrete systems is considered. The method is based on a recently proposed 2-D stability test by the author. Illustrative examples are also included.
Area efficient architectures for information integrity in cache memories
Authors: Seongwoo Kim, Arun K. Somani
Venue: ACM SIGARCH Computer Architecture News (1999)

Information integrity in cache memories is a fundamental requirement for dependable computing. Conventional architectures for enhancing cache reliability using check codes make it difficult to trade between the level of data integrity and the chip area requirement. We focus on transient fault tolerance in primary cache memories and develop new architectural solutions, to maximize fault coverage when the budgeted silicon area is not sufficient for the conventional configuration of an error checking code. The underlying idea is to exploit the corollary of reference locality in the organization and management of the code. A higher protection priority is dynamically assigned to the portions of the cache that are more error-prone and have a higher probability of access. The error-prone likelihood prediction is based on the access frequency. We evaluate the effectiveness of the proposed schemes using a trace-driven simulation combined with software error injection using four different fault manifestation models. From the simulation results, we show that for most benchmarks the proposed architectures are effective and area efficient for increasing the cache integrity under all four models.
Galois Graphs: Walks, Trees and Automorphisms
Authors: Josep M. Brunat, Joan-C. Lario
Venue: Journal of Algebraic Combinatorics: An International Journal (1999)

Given a symmetric polynomial &Phi;(x, y) over a perfect field k of characteristic zero, the Galois graph G(&Phi;) is defined by taking the algebraic closure <?TeX="\bar{k}"> as the vertex set and adjacencies corresponding to the zeroes of &Phi;(x, y). Some graph properties of G(&Phi;), such as lengths of walks, distances and cycles are described in terms of &Phi;. Symmetry is also considered, relating the Galois group Gal(<?TeX="\bar{k}/k">) to the automorphism group of certain classes of Galois graphs. Finally, an application concerning modular curves classifying pairs of isogeny elliptic curves is revisited.
Multicast routing with resource reservation
Authors: Bala Rajagopalan, Raj Nair
Venue: Journal of High Speed Networks (1998)

The integrated services Internet architecture introduces the need for receiver-initiated multicast routing of flows with heterogeneous resource requirements. Multicast routing with resource reservation, however, raises many issues. First, there is a scalability problem semi; straightforward decentralized implementations of Steiner heuristics require complete information on resource allocation for each multicast flow at every router. This is in addition to the basic scalability concerns with Internet multicasting when dealing with large and dynamic groups. Second, there is an efficiency issue semi; receiver-initiated, decentralized multicast routing may lead to inefficient resource allocation if not properly designed. Third, there is a potential for incorrect operation when multicast delivery paths are constructed in an uncoordinated manner. Finally, the integration of the resource reservation model with multicast routing is an issue. This paper describes these problems and proposes solutions that address them, based on decentralized implementations of a new heuristic. Detailed analyses of the proposed schemes using simulations indicate good performance and acceptable overheads.
Turbo-charging vertical mining of large databases
Authors: Pradeep Shenoy, Jayant R. Haritsa, S. Sudarshan, Gaurav Bhalotia, Mayank Bawa, Devavrat Shah
Venue: ACM SIGMOD Record (2000)

In a vertical representation of a market-basket database, each item is associated with a column of values representing the transactions in which it is present. The association-rule mining algorithms that have been recently proposed for this representation show performance improvements over their classical horizontal counterparts, but are either efficient only for certain database sizes, or assume particular characteristics of the database contents, or are applicable only to specific kinds of database schemas. We present here a new vertical mining algorithm called VIPER, which is general-purpose, making no special requirements of the underlying database. VIPER stores data in compressed bit-vectors called &ldquo;snakes&rdquo; and integrates a number of novel optimizations for efficient snake generation, intersection, counting and storage. We analyze the performance of VIPER for a range of synthetic database workloads. Our experimental results indicate significant performance gains, especially for large databases, over previously proposed vertical and horizontal mining algorithms. In fact, there are even workload regions where VIPER outperforms an optimal, but practically infeasible, horizontal mining algorithm.
Ill-Conditioned Convex Processes and Conic
Authors: Morris A. Cohen, Yu-Sheng Zheng, Yunzeng Wang, A. S. Lewis
Venue: Mathematics of Operations Research (1999)

We prove the smallest possible norm of a linear perturbation making a closed convex process nonsurjective is the inverse of the norm of the inverse process. This generalizes the fundamental property of the condition number of a linear map. We then apply this result to strengthen a theorem of Renegar measuring the size of perturbation necessary to make a conic linear system inconsistent.
Design and Performance Evaluation of a Portable Parallel Library for Space-Time Adaptive Processing
Authors: James M. Lebak, Adam W. Bojanczyk
Venue: IEEE Transactions on Parallel and Distributed Systems (2000)

Space-time adaptive processing (STAP) refers to a class of methods for detecting targets using an array of sensors. Various STAP methods use similar operations on different data or in different orders. We have developed a portable, parallel library of subroutines for prototyping STAP methods. The subroutines work on the IBM SP2 and the Intel Paragon under three different operating systems and three different communication libraries, and can also be configured for other systems. We provide execution-time models for predicting the performance of each subroutine. Using the library routines, we created a parallel version of element-space pre-Doppler processing, three parallel versions of higher-order post-Doppler processing, and two versions of PRI-staggered post-Doppler processing. We implemented a fourth version of higher-order post-Doppler processing, the hybrid method, which uses a combination of fine-grain and coarse-grain parallelism to reduce execution time. The hybrid method can be used to improve performance when a large number of processors is available. Our execution time models generally predict the best method and predict execution times to within 10 percent or better for large test cases.
Automatic compiler techniques for thread coarsening for multithreaded architectures
Authors: Gary M. Zoppetti, Gagan Agrawal, Lori Pollock, Jose Nelson Amaral, Xinan Tang, Guang Gao
Venue: Proceedings of the 14th international conference on Supercomputing (2000)

Multithreaded architectures are emerging as an important class of parallel machines. By allowing fast context switching between threads on the same processor, these systems hide communication and synchronization latencies and allow scalable parallelism for dynamic and irregular applications. Thread partitioning is the most important task in compiling high-level languages for multithreaded architectures. Non-preemptive multithreaded architectures, which can be built from off-the-shelf components, require that if a thread issues a potentially remote memory request, then any statement that is dependent upon this request must be in a separate thread.When performing thread partitioning on codes that use pointer-based recursive data structures, it is often difficult to extract accurate dependence information. As a result, threads of unnecessarily small granularity get generated, which, because of thread switching costs, leads to increased execution time. In this paper, we present three techniques that lead to improved extraction and representation of dependence information in the presence of structured control flow, references through fields of structures, and pointer-based data structures. The benefit of these techniques is the generation of coarser-grained threads and, therefore, decreased execution time. Our experiments were performed using the EARTH-C compiler and the EARTH multithreaded architecture model emulated on both a cluster of Pentium PCs and a distributed memory multiprocessor. On our set of 6 pointer-based programs, these techniques reduced the static number of threads by 38%. Reductions in execution times ranged from 16% to 45% on the four programs we measured runtime performance.
Convergence Rates of a Regularized Newton Method in Sound-Hard Inverse Scattering
Authors: Thorsten Hohage
Venue: SIAM Journal on Numerical Analysis (1998)

The iteratively regularized Gauss--Newton method is used to solve an inverse acoustic scattering problem with Neumann boundary conditions in two space dimensions, which is known to be nonlinear and severely ill posed. Some recent results on the speed of convergence for such problems are considered, and numerical experiments yield logarithmic convergence rates, as expected. Moreover, we present an efficient method to numerically evaluate the Fr&eacute;chet derivative using its characterization as a boundary value problem and prove fast convergence of this method.
Algorithms for the Simple Equal Flow Problem
Authors: Ravindra K. Ahuja, James B. Orlin, Giovanni M. Sechi, Paola Zuddas
Venue: Management Science (1999)

The minimum cost flow problem is to determine a least cost shipment of a commodity through a network G = (N, A) in order to satisfy demands at certain nodes from available supplies at other nodes. In this paper, we study a variant of the minimum cost flow problem where we are given a set [math not displayed] of arcs and require that each arc in R must carry the same amount of flow. This problem, which we call the simple equal flow problem, arose while modeling a water resource system management in Sardinia, Italy. We consider the simple equal flow problem in a directed network with n nodes, m arcs, and where all arc capacities and node supplies are integer and bounded by U. We develop several algorithms for the simple equal flow problem-the network simplex algorithm, the parametric simplex algorithm, the combinatorial parametric algorithm, the binary search algorithm, and the capacity scaling algorithm. The binary search algorithm solves the simple equal flow problem in O(log(nU)) applications of any minimum cost flow algorithm. The capacity scaling algorithm solves it in O(m(m + n log n) log (nU)) time, which is almost the same time needed to solve the minimum cost flow problem by the capacity scaling algorithm. These algorithms can be easily modified to obtain an integer solution of the simple equal flow problem.
Self-Directed Learning and Its Relation to the VC-Dimension and to Teacher-Directed Learning
Authors: Shai Ben-David, Nadav Eiron
Venue: Machine Learning (1998)

We study the self-directed (SD) learning model. In this model a learner chooses examples, guesses their classification and receives immediate feedback indicating the correctness of its guesses. We consider several fundamental questions concerning this model: the parameters of a task that determine the cost of learning, the computational complexity of a student, and the relationship between this model and the teacher-directed (TD) learning model. We answer the open problem of relating the cost of self-directed learning to the VC-dimension by showing that no such relation exists. Furthermore, we refute the conjecture that for the intersection-closed case, the cost of self-directed learning is bounded by the VC-dimension. We also show that the cost of SD learning may be arbitrarily higher that that of TD learning.Finally, we discuss the number of queries needed for learning in this model and its relationship to the number of mistakes the student incurs. We prove a trade-off formula showing that an algorithm that makes fewer queries throughout its learning process, necessarily suffers a higher number of mistakes.
Note: Optimal Ordering Decisions with Uncertain Cost and Demand Forecast Updating
Authors: Haresh Gurnani, Christopher S. Tang
Venue: Management Science (1999)

We determine the optimal ordering policy for a retailer who has two instants to order a seasonal product from a manufacturer prior to a single selling season. While the demand is uncertain, the retailer can improve the forecast by utilizing the market signals observed between the first and second instants. However, because of the nature of the manufacturing environment, the unit cost at the second instant is uncertain and could be higher (or lower) than the unit cost at the first instant. To determine the profit-maximizing ordering strategies at both instants, the retailer has to evaluate the trade-off between a more accurate forecast and a potentially higher unit cost at the second instant. We present a nested newsvendor model for determining the optimal order quantity at each instant and characterize the conditions under which it is optimal for the retailer to delay its order until the second instant.
Are Tradeoffs Inherent in Diversification Moves? a Simultaneous Model for Type of Diversification and Mode of Expansion Decisions
Authors: Sayan Chatterjee, Jagdip Singh
Venue: Management Science (1999)

Drawing on the premise that the diversification decisions are driven by antecedent factors such as a firm's existing resources (Teece 1982) and industry structural conditions, this paper develops formal hypotheses for reciprocity between the type of diversification and mode of expansion decisions. We consider the specificity of antecedent resources that affect these two decisions and conceptually demonstrate that there is a contradictory tension in trying to optimize the decisions jointly implying that one or both diversification decisions have to be sub-optimized (i.e., there has to be a trade-off). We make a conceptual argument that this sub-optimization is likely to be in the form of subordination of the mode decision subject to constraints impo sed by resources that are highly specific to the mode decision. Following this, we empirically investigate this contradictory tension by using a simultaneous equation model (SEM) on a large sample of firms between 1981 and 1989. The results suggest that one antecedent factor-internal funds-act as the key mediating influence in the joint optimization and leads to a subordination of the mode decision in the joint optimization process. However, the existence of time compression economies and market power benefits are the exceptions to this subordination and trade off process.