ppxscal/embedding_network huggingface dataset:
Demand assignment control in a satellite switched CDMA network
Authors: Diakoumis Gerakoulis
Venue: International Journal of Network Management (2000)

The Satellite Switched Code Division Multiple Access &lpar;SS&ndash;CDMA&rpar; is a system proposed for geostationary satellite fixed service communications and provides both multiple access and switching to a multibeam satellite. Multiple access is achieved by space, frequency and code division while the switching function is based on code division methods. In this article, we present an overview of the system architecture, focus on the demand assignment control mechanism and describe the call control operation. Copyright &copy; 2000 John Wiley Sons, Ltd.
Global Total Variation Minimization
Authors: Françoise Dibos, Georges Koepfler
Venue: SIAM Journal on Numerical Analysis (1999)

The minimization of the total variation is an important tool of image processing. A lot of authors have addressed the problem and developed algorithms for image denoising. In this paper we present an alternative approach of the total variation minimization problem. After an introduction to the topic and a review of related work, we give a short development of the bounded variation (BV) background. Then we present our global total variation minimization model and proof its validity. Furthermore we introduce a practical algorithm which handles digital image data and we give experimental results.
Algorithm 790: CSHEP2D: cubic Shepard method for bivariate interpolation of scattered data
Authors: Robert J. Renka
Venue: ACM Transactions on Mathematical Software (TOMS) (1999)

We describe a new algorithm for scattered data interpolation. The method is similar to that of Algorithm 660 but achieves cubic precision and C2 continuity at very little additional cost. An accompanying article presents test results that show the method to be among the most accurate available.
Concurrent set manipulation without locking
Authors: Vladimir Lanin, Dennis Shasha
Venue: Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1988)

Set manipulation consists of the actions insert, delete, and member on keys. We propose a concurrent set manipulation algorithm that uses no locking at all and requires no aborts, relying instead on atomic read-modify-write operations on single (data) locations. The algorithm satisfies order-preserving serializability through conditions that are strictly looser than existing algorithms
Newton's Mesh Independence Principle for a Class Of Optimal Shape Design Problems
Authors: Manfred Laumen
Venue: SIAM Journal on Control and Optimization (1999)

Many optimal shape design problems can be stated as infinite dimensional minimization problems. For deriving an implementable algorithm it has to be decided either to discretize the problem and to use a finite algorithm to solve the discrete problem or to state an algorithm in function space and to discretize this algorithm. This issue has yet to be addressed in the field of optimal shape design research. One big advantage for the latter procedure is a mesh independence behavior as it has been proven by Allgower et al. [ SIAM J. Numer. Anal., 23 (1986), pp. 160--169]. Since their assertions are not directly applicable to these specific kinds of problems, a modified version of their mesh independence principle is given here in order to derive more efficient algorithms for the resulting large scale problems.
On the interconnection of causal memory systems
Authors: Antonio Fernández, Ernesto Jiménez, Vicent Cholvi
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

A large amount of work has been invested in devising algorithms to implement distributed shared memory (DSM) systems under different consistency models. However, to our knowledge, the possibility of interconnecting DSM systems with simple protocols and the consistency of the resulting system has never been studied. With this paper, we start a series of works on the properties of the interconnection of DSM systems, which tries to fill this void. In this paper, we look at the interconnection of propagation-based causal DSM systems. We present extremely simple algorithms to interconnect two such systems (possibly implemented with different algorithms), that only require the existence of a bidirectional reliable FIFO channel connecting one process from each system. We show that the resulting DSM system is also causal. This result can be generalized to interconnect any number of DSM propagation-based causal systems.
Least Squares Estimation of 3D Shape and Motion of Rigid Objects from Their Orthographic Projections
Authors: Yiannis Xirouhakis, Anastasios Delopoulos
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

The extraction of motion and shape information of three-dimensional objects from their two-dimensional projections is a task that emerges in various applications such as computer vision, biomedical engineering, and video coding and mining especially after the recent guidelines of the Motion Pictures Expert Group regarding MPEG-4 and MPEG-7 standards. Present work establishes a novel approach for extracting the motion and shape parameters of a rigid three-dimensional object on the basis of its orthographic projections and the associated motion field. Experimental results have been included to verify the theoretical analysis.
Parallel Computing on an Ethernet Cluster of Workstations: Opportunities and Constraints
Authors: Mounir Hamdihamdi, Yi Pan, B. Hamidzadeh, F. M. Lim
Venue: The Journal of Supercomputing (1999)

Parallel computing on clusters of workstations is receiving much attention from the research community. Unfortunately, many aspects of parallel computing over this parallel computing engine is not very well understood. Some of these issues include the workstation architectures, the network protocols, the communication-to-computation ratio, the load balancing strategies, and the data partitioning schemes. The aim of this paper is to assess the strengths and limitations of a cluster of workstations by capturing the effects of the above issues. This has been achieved by evaluating the performance of this computing environment in the execution of a parallel ray tracing application through analytical modeling and extensive experimentation. We were successful in illustrating the effect of major factors on the performance and scalability of a cluster of workstations connected by an Ethernet network. Moreover, our analytical model was accurate enough to agree closely with the experimental results. Thus, we feel that such an investigation would be helpful in understanding the strengths and weaknesses of an Ethernet cluster of workstation in the execution of parallel applications.
Accurate Symmetric Indefinite Linear Equation Solvers
Authors: Cleve Ashcraft, Roger G. Grimes, John G. Lewis
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

The Bunch-Kaufman factorization is widely accepted as the algorithm of choice for the direct solution of symmetric indefinite linear equations; it is the algorithm employed in both LINPACK and LAPACK. It has also been adapted to sparse symmetric indefinite linear systems.While the Bunch--Kaufman factorization is normwise backward stable, its factors can have unusual scaling, with entries bounded by terms depending both on |A| and on $\kappa(A)$. This scaling, combined with the block nature of the algorithm, may degrade the accuracy of computed solutions unnecessarily. Overlooking the lack of a triangular factor bound leads to a further complication in LAPACK such that the LAPACK Bunch--Kaufman factorization can be unstable. We present two alternative algorithms, close cousins of the Bunch-Kaufman factorization, for solving dense symmetric indefinite systems. Both share the positive attributes of the Bunch-Kaufman algorithm but provide better accuracy by bounding the triangular factors. The price of higher accuracy can be kept low by choosing between our two algorithms. One is appropriate as the replacement for the blocked LAPACK Bunch-Kaufman factorization; the other would replace the LINPACK-like unblocked factorization in LAPACK.Solving sparse symmetric indefinite systems is more problematic. We conclude that the Bunch-Kaufman algorithm cannot be rescued effectively in the sparse case. Imposing the constraint of bounding the triangular factors leads naturally to one particular version of the Duff-Reid algorithm, which we show gives better accuracy than Liu's sparse variant of the Bunch-Kaufman algorithm. We extend the work of Duff and Reid in two respects that often provide higher efficiency: a more effective procedure for finding pivot blocks and a stable extension to pivot blocks of size larger than two.
An auto-adaptive dead reckoning algorithm for distributed interactive simulation
Authors: Wentong Cai, Francis B. S. Lee, L. Chen
Venue: Proceedings of the thirteenth workshop on Parallel and distributed simulation (1999)

This paper describes a new, auto-adaptive algorithm for dead reckoning in DIS. In general dead-reckoning algorithms use a fixed threshold to control the extrapolation errors. Since a fixed threshold cannot adequately handle the dynamic relationships between moving entities, a multi-level threshold scheme is proposed. The definition of threshold levels is based on the concepts of area of interest (AOI) and sensitive region (SR), and the levels of threshold are adaptively adjusted based on the relative distance between entities during the simulation. Various experiments were conducted. The results show that the proposed auto-adaptive dead reckoning algorithm can achieve considerable reduction in update packets without sacrificing accuracy in extrapolation.
Affine Structure and Motion from Points, Lines and Conics
Authors: Fredrik Kahl, Anders Heyden
Venue: International Journal of Computer Vision (1999)

In this paper several new methods for estimating scene structure and camera motion from an image sequence taken by affine cameras are presented. All methods can incorporate both point, line and conic features in a unified manner. The correspondence between features in different images is assumed to be known.Three new tensor representations are introduced describing the viewing geometry for two and three cameras. The centred affine epipoles can be used to constrain the location of corresponding points and conics in two images. The third order, or alternatively, the reduced third order centred affine tensors can be used to constrain the locations of corresponding points, lines and conics in three images. The reduced third order tensors contain only 12 components compared to the 16 components obtained when reducing the trifocal tensor to affine cameras.A new factorization method is presented. The novelty lies in the ability to handle not only point features, but also line and conic features concurrently. Another complementary method based on the so-called closure constraints is also presented. The advantage of this method is the ability to handle missing data in a simple and uniform manner. Finally, experiments performed on both simulated and real data are given, including a comparison with other methods.
Teaching tools for software engineering education
Authors: Martin Dick, Margot Postema, Jan Miller
Venue: ACM SIGCSE Bulletin (2000)

This paper examines a set of teaching tools in the Software Engineering Practice course at Monash University. Analyzing various aspects of the course and student survey response to their value provides evaluation of the overall success of the tools. The paper demonstrates that a successful teaching program needs to combine a range of teaching tools to achieve its aims.
Priority Scheduling of Transactions in Distributed Real-TimeDatabases
Authors: Victor C. S. Lee, Kam-Yiu Lam, Ben Kao
Venue: Real-Time Systems (1999)

One of the most important issues in the design of distributed real-time database system (DRTDBS) is transaction scheduling which consists of two parts: priority scheduling and real-time concurrency control. In the past studies, mostly, these issues are studied separately although they have a very close interaction with each other. In this paper, we propose new priority assignment policies for DRTDBS and study their impact on two typical real-time concurrency control protocols (RT-CCPs), High Priority Two Phase Locking (HP-2PL) and Optimistic Concurrency Control with Broadcast Commit (OCC-BC). Our performance results show that many factors, such as data conflict resolution, degree of data contention and transaction restarts, that are unique to database systems, have significant impact on the performance of the policies which in turn affect the performance of the real-time concurrency control protocols. OCC-BC is more affected by the priority assignment policies than HP-2PL owing to the late detection of conflict. In the design of priority assignment policies, we have found that neither the purely deadline driven policies nor data contention driven policies are suitable for DRTDBS. Our proposed policy, the Mixed Method (MM), which considers both transaction timeliness and data contention, outperforms other policies over a wide range of system parameter settings.
Integral Control of Infinite-Dimensional Linear Systems Subject to Input Saturation
Authors: H. Logemann, E. P. Ryan, S. Townley
Venue: SIAM Journal on Control and Optimization (1998)

Closing the loop around an exponentially stable single-input single-output regular linear system, subject to a globally Lipschitz and nondecreasing actuator nonlinearity and compensated by an integral controller, is shown to ensure asymptotic tracking of constant reference signals, provided that (a) the steady-state gain of the linear part of the plant is positive, (b) the positive integrator gain is sufficiently small, and (c) the reference value is feasible in a very natural sense. The class of actuator nonlinearities under consideration contains standard nonlinearities important in control engineering such as saturation and deadzone.
Local Structure When All Maximal Independent Sets Have Equal Weight
Authors: Yair Caro, M. N. Ellingham, J. E. Ramey
Venue: SIAM Journal on Discrete Mathematics (1998)

In many combinatorial situations there is a notion of independence of a set of points. Maximal independent sets can be easily constructed by a greedy algorithm, and it is of interest to determine, for example, if they all have the same size or the same parity. Both of these questions may be formulated by weighting the points with elements of an abelian group, and asking whether all maximal independent sets have equal weight. If a set is independent precisely when its elements are pairwise independent, a graph can be used as a model. The question then becomes whether a graph, with its vertices weighted by elements of an abelian group, is well-covered, i.e., has all maximal independent sets of vertices with equal weight. This problem is known to be co-NP-complete in general. We show that whether a graph is well-covered or not depends on its local structure. Based on this, we develop an algorithm to recognize well-covered graphs. For graphs with n vertices and maximum degree $\Delta$, it runs in linear time if $\Delta$ is bounded by a constant, and in polynomial time if $\Delta = O(\root 3 \of {\log n})$. We mention various applications to areas including hypergraph matchings and radius k independent sets. We extend our results to the problem of determining whether a graph has a weighting which makes it well-covered.
The data locality of work stealing
Authors: Umut A. Acar, Guy E. Blelloch, Robert D. Blumofe
Venue: Proceedings of the twelfth annual ACM symposium on Parallel algorithms and architectures (2000)

This paper studies the data locality of the work-stealing scheduling algorithm on hardware-controlled shared-memory machines. We present lower and upper bounds on the number of cache misses using work stealing, and introduce a locality-guided work-stealing algorithm along with experimental validation. As a lower bound, we show that there is a family of multi-threaded computations Gn each member of which requires &THgr;(n) total instructions (work) for which when using work-stealing the number of cache misses on one processor is constant, while even on two processors the total number of cache misses is &OHgr;(n). This implies that for general computations there is no useful bound relating multiprocessor to uninprocessor cache misses. For nested-parallel computations, however, we show that on P processors the expected additional number of cache misses beyond those on a single processor is bounded by O(C&lceil;m/s PT&infin;), where m is the execution time of an instruction incurring a cache miss, s is the steal time, C is the size of cache, and T&infin; is the number of nodes on the longest chain of dependences. Based on this we give strong bounds on the total running time of nested-parallel computations using work stealing. For the second part of our results, we present a locality-guided work stealing algorithm that improves the data locality of multi-threaded computations by allowing a thread to have an affinity for a processor. Our initial experiments on iterative data-parallel applications show that the algorithm matches the performance of static-partitioning under traditional work loads but improves the performance up to 50% over static partitioning under multiprogrammed work loads. Furthermore, the locality-guided work stealing improves the performance of work-stealing up to 80%.
On Construction of a Family of Smooth Nonseparable Prewavelets via Infinite Products of Triangularizable Matrices
Authors: Mohsen Maesumi
Venue: SIAM Journal on Matrix Analysis and Applications (1998)

Infinite products of matrices arise in many areas, such as the study of subdivision and interpolation schemes, Markov chains, and construction of wavelets of compact support. These products are used here to give sufficient conditions for the continuity and differentiability of a class of rectangular compactly supported nonseparable N-dimensional prewavelets or scaling functions. This paper considers the dilation equation $\phi(X)=\sum_K C_K \phi(2X-K)$, where $K\in \{0, \ldots, m\}^N$, $\phi : {\cal R}^N \to {\cal R}$, and $C_K \in {\cal R}$. First, the one-dimensional case is studied, and sufficient conditions on CK, which guarantee a continuous scaling function $\phi(X)$, are given. These conditions are based on simultaneous triangularizability of two special matrices with entries in terms of CK. Then, these results are generalized to N dimensions and applied to the particular case where CK's are obtained by binomial interpolation of their values at the corners of the N-cube, $\{0,m\}^N$. A set of inequalities, based on sums of CK's on the corners of various faces of the N-cube gives sufficient conditions for the existence of smooth solutions to the dilation equation.
CA-STAR: a centrally-arbitrated broadcast-and-select star architecture for lightwave networks
Authors: Victor Yau, Krzysztof Pawlikowski
Venue: Journal of High Speed Networks (2000)

Parallel use of multiple channels in WDM star networks requires that either each station is equipped with one receiver per channel or we have to deal with destination conflicts whenever a station is reached by more packets than it is able to receive. Earlier proposed networks resolved destination conflicts either after they occur (applying the detect-and-retransmit-if-lost principle) or before packets are transmitted (applying the request-schedule-then-transmit principle). This paper introduces networks in which such conflicts are resolved whilst packets are en route to their destinations, using a central arbiter station (CA) located at the star coupler. CA detects destination conflicts, buffers packets which would otherwise be lost, and forwards them to their destinations as soon as their destinations are free to receive them. Buffer operations at CA are streamlined, allowing either electronic implementation or a simple optical delay-line implementation. Their performance is evaluated by studying their delay and throughput characteristics, protocol computational complexity, E/O conversion overhead, and hardware demands.
Power Reduction in Custom CMOS Digital Filter Structures
Authors: Pontus Åström, Peter Nilsson, Mats Torkelson
Venue: Analog Integrated Circuits and Signal Processing (1999)

Today the main optimization parameter of digital filters is the filter order. By the aid of two implemented filters we will show that both power and speed can be enhanced if the optimization effort is made on reducing the filter coefficient lengths rather than minimizing the order. Both filters have been designed from the same specification, one as a standard minimum order filter, the other as a filter with short coefficients found by a computer search. The minimum order filter is of order three with seven bits long coefficients. The coefficient optimized filter is of order six with two bits long coefficients. Both filters were implemented with bit-serial fixed coefficient arithmetic in two&rsquo;s complement representation in a 0.8\, \mu , two metal layers CMOS process. Measurements show an eightfold speedup at half the power consumption and only 30% area cost for the coefficient optimized filter.
Force-feedback improves performance for steering and combined steering-targeting tasks
Authors: Jack Tigh Dennerlein, David B. Martin, Christopher Hasser
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

The introduction of a force-feedback mouse, which provides high fidelity tactile cues via force output, may represent a long-awaited technological breakthrough in pointing device designs. However, there have been few studies examining the benefits of force-feedback for the desktop computer human interface. Ten adults performed eighty steering tasks, where the participants moved the cursor through a small tunnel with varying indices of difficulty using a conventional and force-feedback mouse. For the force-feedback condition, the mouse displayed force that pulled the cursor to the center of the tunnel. The tasks required both horizontal and vertical screen movements of the cursor. Movement times were on average 52 percent faster during the force-feedback condition when compared to the conventional mouse. Furthermore, for the conventional mouse vertical movements required more time to complete than horizontal screen movements. Another ten adults completed a combined steering and targeting task, where the participants navigated through a tunnel and then clicked a small box at the end of the tunnel. Again, force-feedback improved times to complete the task. Although movement times were slower than the pure steering task, the steering index of difficulty dominated the steering-targeting relationship. These results further support that human computer interfaces benefit from the additional sensory input of tactile cues to the human user.
Optimal Control of a Variational Inequality with Application to Equilibrium Problem of an Elastic Nonhomogeneous and Anisotropic Plate Resting on Unilateral Elastic Foundation
Authors: Ján Lovíšek
Venue: Computational Optimization and Applications (1998)

Several optimal control problems with the same state problem&mdash;a variational inequality with a monotone operator&mdash;are considered. The inequality represents bending of an elastic, nonhomogeneous, anisotropic Kirchhoff plate resting on some unilateral elasto-rigid foundation and point supports. Both the thickness of the plate and the coefficient of the unilateral elastic foundation play the role of design variables. Cost functionals include the work of external forces (compliance), total reaction forces of the foundation or the weight of the plate. The solvability of all the problems is proved. Moreover, approximate methods for the optimal control and weight minimization problems are proposed, making use of finite elements. The design variables are approximated by piecewise affine functions. The solvability of the approximate problems is proved and some convergence analysis is presented.