ppxscal/embedding_network huggingface dataset:
The liquid architecture: a non-linear peer-to-peer distributed architecture with polymorphic message passing
Authors: Coskun Bayrak, Chad Davis
Venue: ACM SIGSOFT Software Engineering Notes (2003)

In terms of benefiting from the potential to be gained from full distribution, today's most common implementations of distributed systems follow only limited linear versions of distribution such as client-server or n-tier models. Even many "peer to peer" systems still rely on centralized servers to provide the message passing connectivity between the peers. While these systems do provide increased robustness and computational speedup, they fail to realize the full measure of what fully distributed architectures offer.With many of the techno-historical reasons behind these linear distributed systems becoming obsolete, we should try to think of new, more truly distributed models. Fully distributed architectures should demonstrate the ability to move functionality to a completely contingent set of machines determined at or just prior to run time. Under such an architecture -- a" liquid" architecture, functionality and data are completely freed from any fixed locations or functional paths and may flow at will. Especially in the domain of shared space applications such as chat and pseudochat (i.e. instant messaging) services, and virtual collaboration, the flexibility and security to be gained from the full distribution of a liquid architecture represent not only premium benefits but possibly core requisites to their essential purpose and functionality.This paper examines the notion of a liquid architecture and explores a case study implementation of such an architecture via the Virtual Collaboration Tool introduced below.
The Metaverse: a networked collection of inexpensive, self-configuring, immersive environments
Authors: C. Jaynes, W. B. Seales, K. Calvert, Z. Fei
Venue: Proceedings of the workshop on Virtual environments 2003 (2003)

Immersive projection-based display environments have been growing steadily in popularity. However, these systems have, for the most part, been confined to laboratories or other special-purpose uses and have had relatively little impact on human-computer interaction or user-to-user communication/collaboration models. Before large-scale deployment and adoption of these technologies can occur, some key technical issues must be resolved. We address these issues in the design of the Metaverse. In particular, the Metaverse system supports automatic self-calibration of an arbitrary number of projectors, thereby simplifying system's setup and maintenance. The Metaverse also supports novel communication models that enhance the scalability of the system and facilitate collaboration between Metaverse portals. Finally, we describe a prototype implementation of the Metaverse.
Effects of uncertainties in the domain on the solution of Neumann boundary value problems in two spatial dimensions
Authors: Ivo Babuska, Jan Chleboun
Venue: Mathematics of Computation (2002)

An essential part of any boundary value problem is the domain on which the problem is defined. The domain is often given by scanning or another digital image technique with limited resolution. This leads to significant uncertainty in the domain definition. The paper focuses on the impact of the uncertainty in the domain on the Neumann boundary value problem (NBVP). It studies a scalar NBVP defined on a sequence of domains. The sequence is supposed to converge in the set sense to a limit domain. Then the respective sequence of NBVP solutions is examined. First, it is shown that the classical variational formulation is not suitable for this type of problem as even a simple NBVP on a disk approximated by a pixel domain differs much from the solution on the original disk with smooth boundary. A new definition of the NBVP is introduced to avoid this difficulty by means of reformulated natural boundary conditions. Then the convergence of solutions of the NBVP is demonstrated. The uniqueness of the limit solution, however, depends on the stability property of the limit domain. Finally, estimates of the difference between two NBVP solutions on two different but close domains are given.
Visualizing Java in action
Authors: Steven P. Reiss
Venue: Proceedings of the 2003 ACM symposium on Software visualization (2003)

Dynamic software visualization is supposed to provide programmers with insights as to what the program is doing. Most current dynamic visualizations either use program traces to show information about prior runs, slow the program down substantially, show only minimal information, or force the programmer to indicate when to turn visualizations on or off. We have developed a dynamic Java visualizer that provides a view of a program in action with low enough overhead so that it can be used almost all the time by programmers to understand what their program is doing while it is doing it.
"It/I": a theater play featuring an autonomous computer character
Authors: Claudio S. Pinhanez, Aaron F. Bobick
Venue: Presence: Teleoperators and Virtual Environments (2002)

"It/I" is a two-character theater play in which the human character I (played by a real actor) is taunted and played with by an autonomous computer character It on a computer-controlled, camera-monitored stage. The play, performed before live audiences in November 1997, brought an automatic computer character to a theatrical stage for the first time ever. This paper reports the experience and examines important technical developments needed for the successful production of "It/I". In particular we describe the interval script paradigm used to program the computer character and the ACTSCRIPT language for communication of actions and goals. Although our experiments have been restricted to physical interactive spaces, we believe that interval scripts and ACTSCRPT can successfully address the control and management of any virtual environment with a complex temporal structure or a strong underlying narrative.
A denotational semantics for Timed Linda
Authors: F. S. de Boer, M. Gabbrielli, M. C. Meo
Venue: Proceedings of the 3rd ACM SIGPLAN international conference on Principles and practice of declarative programming (2001)

In [5] we introduced a Timed Linda language (T-Linda) whic hwas obtained by a natural timed interpretation of the usual constructs of the Linda model and by including a simple primitive for specifying time-outs. Here we define a denotational model for T-Linda which is based on timed reactive sequences. The correctness of this model is proved w.r.t a notion of observ ables which include finite traces of actions and input/output pairs.
The performance advantage of applying compression to the memory system
Authors: Nihar R. Mahapatra, Jiangjiang Liu, Krishnan Sundaresan
Venue: Proceedings of the 2002 workshop on Memory system performance (2002)

The memory system stores information comprising primarily instructions and data and secondarily address information, such as cache tag fields. It interacts with the processor by supporting related traffic (again comprising addresses, instructions, and data). Continuing exponential growth in processor performance, combined with technology, architecture, and application trends, place enormous demands on the memory system to permit this information storage and exchange at a high-enough performance (i.e., to provide low latency and high bandwidth access to large amounts of information). This paper comprehensively analyzes the redundancy in the information (addresses, instructions, and data) stored and exchanged between the processor and the memory system and evaluates the potential of compression in improving performance of the memory system. Analysis of traces obtained with Sun Microsystems' Shade simulator simulating SPARC executables of nine integer and six floating-point programs in the SPEC CPU2000 benchmark suite yield impressive results. Well-designed compression schemes may provide benefits in performance that far outweigh the extra time and logic for compression and decompression. This will be more so in the future since the speed and size of logic (which will be used to perform compression/decompression) are improving and are projected to improve at a much higher rate compared to those of interconnect (which will be used to communicate the information), both on-chip and off-chip.
Gate sizing using Lagrangian relaxation combined with a fast gradient-based pre-processing step
Authors: Hiran Tennakoon, Carl Sechen
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

In this paper, we present Forge, an optimal algorithm for gate sizing using the Elmore delay model. The algorithm utilizes Lagrangian relaxation with a fast gradient-based pre-processing step that provides an effective set of initial Lagrange multipliers. Compared to the previous Lagrangian-based approach, Forge is considerably faster and does not have the inefficiencies due to difficult-to-determine initial conditions and constant factors. We compared the two algorithms on 30 benchmark designs, on a Sun UltraSparc-60 workstation. On average Forge is 200 times faster than the previously published algorithm. We then improved Forge by incorporating a slew-rate-based convex delay model, which handles distinct rise and fall gate delays. We show that Forge is 15 times faster, on average, than the AMPS transistor-sizing tool from Synopsys, while achieving the same delay targets and using similar total transistor area.
Embedded Boundary Scan
Authors: Bradford G. Van Treuren, Jose M. Miranda
Venue: IEEE Design Test (2003)

Editor's note:As boundary scan technology continues to mature, engineers continue tofind innovative ways of using the IEEE Std. 1149.1 facilities throughout thelife cycle of a board. Lucent Technologies is at the forefront of thisdevelopment, and the authors here describe how they have expanded theuse and reuse of the IEEE 1149.1 board tests into a variety of additional testenvironments.ýR.G. (Ben) BennettsBennetts Associates
Delayed frame transmission schemes for MPEG videos in a real-time network
Authors: Joseph Kee-Yin Ng, Victor Chung-Sing Lee
Venue: Virtual shared memory for distributed architectures (2001)

In recent years, real-time systems are likely to be based on distributed architectures and utilize highly parallel algorithms. In such systems, cooperative tasks may be executed on different processors and communicate among each other via a high-speed network. With the growing demand on transmitting digital video in distributed multimedia applications, there is a need to study the on-time delivery of videos over a distributed system. Knowing the fact that unregulated transmission of MPEG video over a computer network may be hazardous to the network performance, in this paper, we exploit the characteristies of MPEG coded frame sequence and devise three transmission schemes for the MPEG video. The crux of the issue is to fully utilize the assigned bandwidth. In our schemes, the delayed frames mechanism can effectively utilize the assigned bandwidth and meet the objective of maximizing the number of video streams that can be supported in a timed token MAC network without sacrificing the video quality. Multiple classes of MPEG video are used in me study. These data are captured from real video programmes and we categorize these video clips according to their traffic burstiness and workload characteristics. The results reveal that by employing the Interstream Delayed Transmission Scheme, we could improve the performance by 66 to 166% depending on the availability of global information. When the technique is applied in an intra-stream level, we could improve the performance by 86%. When we combined these two schemes together, the performance improvement of the Total Delayed Transmission Scheme can be pushed to 178% which is a dramatic improvement over the original unregulated transmission scheme.
A Cutting Plane Algorithm for Multicommodity Survivable Network Design Problems
Authors: Geir Dahl, Mechthild Stoer
Venue: INFORMS Journal on Computing (1998)

We present a cutting plane algorithm for solving the following telecommunications network design problem: given point-to-point traffic demands in a network, specified survivability requirements and a discrete cost/capacity function for each link, find minimum cost capacity expansions satisfying the given demands. This algorithm is based on the polyhedral study described in [19]. In this article we describe the underlying problem, the model and the main ingredients in our algorithm. This includes: initial formulation, feasibility test, separation for strong cutting planes, and primal heuristics. Computational results for a set of real-world problems are reported.
Compiler-directed run-time monitoring of program data access
Authors: Chen Ding, Yutao Zhong
Venue: Proceedings of the 2002 workshop on Memory system performance (2002)

Accurate run-time analysis has been expensive for complex programs, in part because most methods perform on all a data. Some applications require only partial reorganization. An example of this is off-loading infrequently used data from a mobile device. Complete monitoring is not necessary because not all accesses can reach the displaced data. To support partial monitoring, this paper presents a framework that includes a source-to-source C compiler and a run-time monitor. The compiler inserts run-time calls, which invoke the monitor during execution. To be selective, the compiler needs to identify relevant data and their access. It needs to analyze both the content and the location of monitored data. To reduce run-time overhead, the system uses a source-level interface, where the compiler transfers additional program information to reduce the workload of the monitor. The paper describes an implementation for general C programs. It evaluates different levels of data monitoring and their application on an SGI workstation and an Intel PC.
A data assimilation methodology for the plume phase of a nuclear accident
Authors: R. O. Puch, P. Astrup, J. Q. Smith, H. P. Wynn, C. Turcanu, C. Rojas-Palma
Venue: Development and application of computer techniques to environmental studies (2002)

In the aftermath of the Chernobyl nuclear accident and following more than ten years of research and development, the Real time On-line DecisiOn Support system (RODOS) offers a wide range of alternatives to dealing in an effective and efficient fashion with an accidental release of radioactivity to the environment in Europe. The system is intended to provide assistance to decision-makers throughout the various phases of the accident, covering the plume phase (prediction of the atmospheric dispersion), the post-plume phase (assessing the impact of the contamination on the food chain through both aquatic and terrestrial pathways), and the evaluation of the effectiveness of countermeasures issued to protect the public and the environment against the hazards of ionizing radiation. In the framework of the European Commission's Nuclear Fission Programme, a research project on data assimilation has the task of introducing a practical improvement in the predictive capabilities of the RODOS system.
Using reflection as a mechanism for enforcing security policies on compiled code
Authors: Ian Welch, Robert J. Stroud
Venue: Journal of Computer Security (2002)

Securing application resources or defining finer-gained access control for system resources using the Java security architecture requires manual changes to source code. This is error-prone and cannot be done if only compiled code is present. We show how behavioural reflection can be used to enforce security policies on compiled code. Other authors have implemented code rewriting toolkits that achieve the same effect but they either require policies to be expressed in terms of low level abstractions or require the use of new high level policy languages. Our approach allows reuseable policies to be implemented as metaobjects in a high level objecl oriented language (Java), and then bound to application objects at loadtime. The binding between metaobjects and objects is implemented through bytecode rewriting under the control of a declarative binding specification. We have implemented this approach using Kava which is a portable reflective Java implementation. Kava allows customisation of a rich range of runtime behaviour. and provides a non-bypassable meta level suitable for implementing security enforcement. We discuss how we have used Kava to show how to secure a third-party application, how we prevent Kava being bypassed, and compare its performance with non-reflective security enforcement.
A Mathematical Programming Approach for the Solution of the Railway Yield Management Problem
Authors: A. Ciancimino, G. Inzerillo, S. Lucidi, L. Palagi
Venue: Transportation Science (1999)

Railway passenger transportation plays a fundamental role in Europe, particularly in view of the growing number of trains offering valuable services such as high speed travel, high comfort, etc. Hence, it is advantageous to submit seat inventories to a Yield Management system to get the maximum revenue. We consider a deterministic linear programming model and a probabilistic nonlinear programming model for the network problem with non-nested seat allocation. A first comparative analysis of the computational results obtained by the two models, both in terms of the overall expected revenue and in terms of CPU time, is carried out. Furthermore, we describe a new nonlinear algorithm for the solution of the probabilistic nonlinear programming model that exploits the structure of the optimization problem. The numerical results obtained on a set of real data show that, for this class of problems, this algorithm is more efficient than other standard algorithms for nonlinear programming problems.
From Valid Inequalities to Heuristics: a Unified View of Primal-Dual Approximation Algorithms in Covering Problems
Authors: Dimitris Bertsimas, Chung-Piaw Teo
Venue: Operations Research (1998)

In recent years approximation algorithms based on primal-dual methods have been successfully applied to a broad class of discrete optimization problems. In this paper, we propose a generic primal-dual framework to design and analyze approximation algorithms for integer programming problems of the covering type that uses valid inequalities in its design. The worst-case bound of the proposed algorithm is related to a fundamental relationship (called strength) between the set of valid inequalities and the set of minimal solutions to the covering problems. In this way, we can construct an approximation algorithm simply by constructing the required valid inequalities. We apply the proposed algorithm to several problems, such as covering problems related to totally balanced matrices, cyclic scheduling, vertex cover, general set covering, intersections of polymatroids, and several network design problems attaining (in most cases) the best worst-case bound known in the literature.
Safe dynamic multiple inheritance
Authors: Erik Ernst
Venue: Nordic Journal of Computing (2002)

Multiple inheritance and similar mechanisms are usually only supported at compile time in statically typed languages. Nevertheless, dynamic multiple inheritance would be very useful in the development of complex systems, because it allows the creation of many related classes without an explosion in the size and level of redundancy in the source code. In fact, dynamic multiple inheritance is already available. The language gbeta is statically typed and has supported run-time combination of classes and methods since 1997, by means of the combination operator '&'. However, with certain combinations of operands the '&' operator fails; as a result, dynamic creation of new classes and methods was considered a dangerous operation in all cases. This paper presents a large and useful category of combinations, and proves that combinations in this category will always succeed.
Three-dimensional transient elastodynamic analysis by a space and time-discontinuous Galerkin finite element method
Authors: C. C. Chien, C. S. Yang, J. H. Tang
Venue: Finite Elements in Analysis and Design (2003)

This study presents a space and time-discontinous Galerkin (TDG) finite element method for analyzing three-dimensional linear transient elastodynamic problems. This novel method uses both the displacements and velocities as basic unknowns and approximates them as piecewise linear functions which are continuous in space and discontinuous in time. The improved algorithm employs the Gauss-Seidel method to calculate iteratively the solutions that exist in the numerical implementation. Stability analyses of TDG method reveal that such a method retains the unconditionally stable behavior with greater efficiency than other direct time integration algorithms. In addition, numerical examples are presented, demonstrating that the proposed method is more accurate than several commonly used algorithms in structural dynamic applications.
Coordinating Replenishment and Pricing in a Firm
Authors: Qing Li, Derek Atkins
Venue: Manufacturing Service Operations Management (2002)

Replenishment and pricing strategies are traditionally determined by entirely separate units of a firm, the former by production and the latter by marketing. In a large organization production and marketing are traditionally measured in terms of performance criteria appropriate and relevant within the world in which they operate, rather than in terms of overall company performance. We consider a situation where the headquarters uses a simple linear transfer price between the two functions to govern the transactions. The misaligned incentives among these functional managers are caused by a transfer price between them that distorts the marginal production cost and revenue, as well as by a misallocation of cost: Marketing's pricing strategy influences expected leftover inventory, but only production incurs the cost. The misalignment can be mitigated through the following two ways. First, if production commits to a service level instead of an inventory level, both production and marketing, and hence the firm as a whole, are better off. Second, the same improvement can be achieved through organizational changes so that marketing becomes the dominant function. We also propose a mechanism that aligns the functional managers' incentives to be compatible to the firm.
Incremental recomputation in local languages
Authors: Guozhu Dong, Leonid Libkin, Limsoon Wong
Venue: Information and Computation (2003)

We study the problem of maintaining recursively defined views, such as the transitive closure of a relation, in traditional relational languages that do not have recursion mechanisms. The main results of this paper are negative ones: we show that a certain property of query languages implies impossibility of such incremental maintenance The property we use is locality of queries, which is known to hold for relational calculus and various extensions, including those with grouping and aggregate constructs (essentially, plain SQL).
A lower bound on the size of &#x025B;-free NFA corresponding to a regular expression
Authors: Yuri Lifshits
Venue: Information Processing Letters (2003)

Hromkovic et al. showed how to transform a regular expression of size n into an ε-free nondeterministic finite automaton (which defines the same language as the expression) with O(n) states and O(n log2 (n)) transitions. They also established a lower bound Ω (n log(n)) on the number of transitions. We improve the lower bound to Ω(nlog2n/loglogn).
Positive solutions for a class of implicit and discontinuous second order functional differential equations with singularities
Authors: Alberto Cabada, José Angel Cid, Rodrigo L. Pouso
Venue: Applied Mathematics and Computation (2003)

We derive existence and approximation results for a type of implicit second order differential equations related with diffusion processes. Singularities, discontinuities and functional dependence are allowed.