ppxscal/embedding_network huggingface dataset:
Performance and simulation of communications systems with applications to TCM over fading channels
Authors: K. Ben Letaief
Venue: Proceedings of the IEEE Symposium on Computers and Communications (ISCC'95) (1995)

Over the past decade there has been considerable interest in using Monte Carlo (MC) simulation techniques for performance analysis of communications systems. Unfortunately, this approach often becomes intractable because of the prohibitive amount of simulation time required to achieve accurate estimates. Importance sampling is a modified MC technique which can result in a significant reduction in the computational cost required to obtain accurate MC estimates. We illustrate the use of importance sampling for simulating coded communications systems by presenting an efficient importance sampling methodology for simulating trellis code modulation (TCM) over Rayleigh fading channels. In particular, it is demonstrated that the proposed method can estimate the performance of these systems with a high degree of accuracy to warrant its possible use as a powerful tool for performance analysis and design of practical TCM systems.
Mobile Agents for Electing a Leader
Authors: Dwight Deugo
Venue: Proceedings of the The Fourth International Symposium on Autonomous Decentralized Systems (1999)

We present a technique for mapping a distributed algorithm to a set of homogeneous agents that solves the general distributed control problem know as election. Election is a decentralized, cooperative information task where one system or node from n is elected as the leader. Our solution is as efficient as the message-based election algorithm, but does not rely on message passing between custom protocols located on communicating nodes. Rather, the proposed solution relies on mobile agents. We show that the number of agent transfers is equivalent to the number of messages in the original algorithm. We also present an environment model for distributed agents that supports not only the mapping of election agents but other agent-based solution to distributed control problems that use distributed algorithms.
Drawing Directed Acyclic Graphs: An Experimental Study (Preliminary Version)
Authors: Giuseppe D Battista, Ashim Garg, Giuseppe Liotta, Armando Parise, Roberto Tamassia, Emanuele Tassinari, Francesco Vargiu, Luca Vismara
Venue:  (1996)

In this paper we consider the class of directed acyclic graphs (DAGs), and present the results of an experimental study on four drawing algorithms specifically developed for DAGs. Our study is conducted on two large test suites of DAGs and yields more than 30 charts comparing the performance of the drawing algorithms with respect to several quality measures, including area, crossings, bends, and aspect ratio. The algorithms exhibit various trade-offs with respect to the quality measures, and none of them clearly outperforms the others.
Adding Generic Contextual Capabilities to Wearable Computers
Authors: Mr. Jason Pascoe
Venue: Proceedings of the 2nd IEEE International Symposium on Wearable Computers (1998)

Context-awareness has an increasingly important role to play in the development of wearable computing systems. In order to better define this role we have identified four generic contextual capabilities: sensing, adaptation, resource discovery, and augmentation. A prototype application has been constructed to explore how some of these capabilities could be deployed in a wearable system designed to aid an ecologist's observations of giraffe in a Kenyan game reserve. However, despite the benefits of context-awareness demonstrated in this prototype, widespread innovation of these capabilities is currently stifled by the difficulty in obtaining the contextual data. To remedy this situation the Contextual Information Service (CIS) is introduced. Installed on the user's wearable computer, the CIS provides a common point of access for clients to obtain, manipulate and model contextual information independently of the underlying plethora of data formats and sensor interface mechanisms.
Relations Between Diagonalization, Proof Systems, and Complexity Gaps
Authors: Juris Hartmanis
Venue:  (1977)

In this paper we study diagonal processes over time-bounded computations of one-tape Turing machines by diagonalizing only over those machines for which there exist formal proofs that they operate in the given time bound. This replaces the traditional "clock" in resource bounded diagonalization by formal proofs about running times and establishes close relations between properties of proof systems and existence of sharp time bounds for one-tape Turing machine complexity classes. Furthermore, these diagonalization methods show that the Gap Theorem for resource bounded computations does not hold for complexity classes consisting only of languages accepted by Turing machines for which it can be formally proven that they run in the required time bound.
Global solution to a Fremond model for shape memory alloys with thermal memory
Authors: Elena Bonetti
Venue:  (1999)

The aim of this paper is to establish an existence and uniqueness result for a diffusive austenite-martensite phase transition problem related to shape memory alloys with thermal memory. We deal with a Fremond model in the framework of a linearized energy balance equation and of a dissipative variational inequality for the phase variables with diffusion terms. In addition, the heat flux is supposed to satisfy the Cattaneo-Maxwell law, as a particular case of Gurtin and Pipkin''s theory. An initial-boundary value problem is considered and existence and uniqueness of solutions, as well continuous dependence on the data are proved.
Animating Real-Time Reactive Systems
Authors: V. S. Alagar, D. Muthiayen, R. Achuthan
Venue: Proceedings of the 2nd IEEE International Conference on Engineering of Complex Computer Systems (1996)

This paper presents an overview of a process model and an object-oriented environment that supports the process model, for the development of complex real-time reactive systems described using Timed Reactive Object Model. The environment includes an animation tool consisting of a graphical user interface, an interpreter and a simulator, as well as an axiom generator and a verification manager. Debugging, simulating the consequences of exercising a computational step, and verifying invariant properties of an evolving design at different stages of the design process are all permitted.
Motion and structure from multiple cues; image motion, shading flow, and stereo disparity
Authors: Ali Khamene, Shahriar Negahdaripour
Venue: Computer Vision and Image Understanding (2003)

We investigate the recovery of 3-D motion and structure from the stereo images of a stationary environment. A Kalman filter-based framework is proposed for the reconstruction of 3-D structure from multiple visual cues, through the integration of image motion and stereo disparity with the shading flow that is induced by the rotational motion of the source. A common scenario involves the coupled motion of artificial source(s) and stereo cameras that are installed on mobile submersible vehicles. Utilizing shading flow with the image motion leads to devising a more robust 3-D motion estimation algorithm, in addition to the important role in depth recovery/refinement by constraining the local surface gradients. Collectively, use of multiple cues enhances robustness with respect to perturbation in any of the cues. Results of experiments with synthetic and real imagery are presented to evaluate the performance of the proposed algorithm, including the construction of a composite 3-D depth map of an underwater scene from a sequence of stereo pairs.
LEO Satellite Constellation Performance Analysis
Authors: Christopher Ward, T. Chang, Aamer Khan, Phillip Acuff
Venue:  (1993)

To date, radio frequency cross-links have been the preferred communication medium for low earth orbit (LEO) satellite networks. However, laser cross-linking satellite constellations introduce many new and interesting research problems not addressed in these conventional methods. One such problem is communication disruption caused by external noise sources (e.g., background radiation from the Sun and Moon). In this paper we analyze the cross-link connectivity of a particular LEO constellation currently under consideration in the literature (the Iridium project) as a function of solar background radiation. The technique introduced may be generalized to study a variety of different constellations.
Message Classes: An Approach to Process Synchronization
Authors: Gregory R. Andrews
Venue:  (1976)

In multiprogramming systems, parallel processes compete for access to shared resources and cooperate by exchanging information. Semaphores are a useful means for controlling competition and synchronizing execution and inter-process messages are useful for communication. Neither semaphores nor inter-process message, however, are natural for solving both problems. This paper introduces a new approach, message classes, which combines and extends features of both semaphores and message passing. Using message classes, numerous mutual exclusion, producer/consumer, process communication, and resource allocation problems can be readily solved.
Spectral Gradient: A Material Descriptor Invariant to Geometry and Incident Illumination
Authors: Elli Angelopoulou, Sang W. Lee, Ruzena Bajcsy
Venue: Proceedings of the International Conference on Computer Vision-Volume 2 - Volume 2 (1999)

The light reflected from a surface depends on the scene geometry, the incident illumination and the surface material. A novel methodology is presented which extracts reflectivity information of the various materials in the scene independent of incident light and scene geometry. A scene is captured under different narrow-band color filters and the spectral derivatives of the scene are computed. The resulting spectral derivatives form a spectral gradient at each pixel. This spectral gradient is a material descriptor which is invariant to scene geometry and incident illumination for smooth diffuse surfaces. Spectral gradients can discriminate among smooth dielectrics with different reflectance properties independent of viewing conditions.
Automated surface subdivision and tool path generation for 3 &#x00BD;&#x00BD;-axis CNC machining of sculptured parts
Authors: Zezhong C. Chen, Zuomin Dong, Geoffrey W. Vickers
Venue: Computers in Industry (2003)

As an innovative and cost-effective method for carrying out multiple-axis CNC machining, 3½½-axis CNC machining technique adds an automatic indexing/rotary table with two additional discrete rotations to a regular 3-axis CNC machine, to improve its ability and efficiency for machining complex sculptured parts. In this work, a new tool path generation method to automatically subdivide a complex sculptured surface into a number of easy-to-machine surface patches; identify the favorable machining set-up/orientation for each patch; and generate effective 3-axis CNC tool paths for each patch is introduced. The method and its advantages are illustrated using an example of sculptured surface machining. The work contributes to automated multiple-axis CNC tool path generation for sculptured part machining and forms a foundation for further research.
A Survey of Architecture Description Languages
Authors: Paul C. Clements
Venue: Proceedings of the 8th International Workshop on Software Specification and Design (1996)

Architecture Description Languages (ADLs) are emerging as viable tools for formally representing the architectures of systems. While growing in number, they vary widely in terms of the abstractions they support and analysis capabilities they provide. Further, many languages not originally designed as ADLs serve reasonably well at representing and analyzing software architectures. This paper summarizes a taxonomic survey of ADLs that is in progress. The survey characterizes ADLs in terms of (a) the classes of systems they support; (b) the inherent properties of the languages themselves; and (c) the process and technology support they provide to represent, refine, analyze, and build systems from an architecture. Preliminary results allow us to draw conclusions about what constitutes an ADL, and how contemporary ADLs differ from each other.
Decentralized Trust Management
Authors: Matt Blaze, Joan Feigenbaum, Jack Lacy
Venue:  (1996)

We identify the "trust management problem" as a distinct and important component of security in network services. Aspects of the trust management problem include formulating security policies and security credentials, determining whether particular sets of credentials satisfy the relevant policies, and deferring trust to third parties. Existing systems that support security in networked applications, including X.509 and PGP, address only narrow subsets of the overall trust management problem and often do so in a manner that is appropriate to only one application. We present a comprehensive approach to trust management, based on a simple language for specifying trusted actions and trust relationships. We also describe a prototype implementation of a "trust management system," called PolicyMaker, that can facilitate the development of security features in a wide range of network services. This paper was presented at the IEEE Symposium on Security and Privacy, Oakland CA, May 1996.
Discovering relationships between service and customer satisfaction
Authors: M. Buckley, R. Chillarege
Venue: Proceedings of the International Conference on Software Maintenance (1995)

Organizations spend significant resources tracking customer satisfaction and managing service delivery. Although a great deal of effort is expended in understanding what goes on within each of these areas, little or no effort has been applied to identifying and quantifying the relationships between the two. The objective of this research is to discover and establish potential relationships between service data and customer satisfaction. This understanding will enable more effective management, which will lead to improved quality, reduced cost and increased customer satisfaction. This study uses three years of data from an IBM operating system to measure the correlation between 15 service variables and nine customer satisfaction attributes. The results show that: (1) There is a relationship between the service data and customer satisfaction. This is the first time the existence of such a relationship has been proven and quantified. (2) The relative order of influence on customer satisfaction, of the four key service measures that are usually tracked, is defective fixes, followed by the number of problems, which in turn are followed by the number of defects and days-to-solution. The latter two were found to have little or no influence on customer satisfaction. (3) There is a return on investment of at least ten to one, for each dollar spent on quality improvement efforts in development.
TimeNET: Evaluation Tool for Non-Markovian Stochastic Petri Nets
Authors: Christian Kelling, Reinhard German, Armin Zimmermann, Guenter Hommel
Venue: Proceedings of the 2nd International Computer Performance and Dependability Symposium (IPDS '96) (1996)

The toolkit TimeNET (Timed Net Evaluation Tool), a software package for the modeling and evaluation of stochastic Petri nets with non-exponentially distributed firing time, is described briefly. TimeNET provides a graphical user interface for the model specification and several specialized analysis and simulation components are used for the automated model evaluation for both, the transient and stationary phase of model evolution. The implementation of the analysis and simulation components is based on recent research results.
Dependability Modelling of Homogeneous and Heterogeneous Distributed Systems
Authors: Yinong Chen, Zhongshi He
Venue: Proceedings of the Fifth International Symposium on Autonomous Decentralized Systems (2001)

In the past few years we have developed an experimental distributed system that supports multi-task applications with different levels of criticality. Software implemented fault-tolerant protocols are used to support dependable computing. This paper first presents Markov models of a distributed system under the occurrence of faults, reconfiguration and repair. As a part of our overall project, these models are intended for solving our particular problems, like assessing the merits of redundant schemes, task allocation and reallocation policies, and fault handling used in our experimental system. However, these models are developed in a generic way. They can also be used in evaluating individual task's reliability, risk and availability under various redundant schemes in any homogeneous distributed system. Then, we extend our study in analysing the dependability of the heterogeneous system consisting of a number homogeneous distributed systems connected through gateways.
A Generalized Term Dependence Model in Information Retrieval
Authors: C. T. Yu, Chris Buckley, K. Lam, Gerard Salton
Venue:  (1983)

The tree dependence model has been used successfully to incorporate dependencies between certain term pairs on the information retrieval process, while the Bahadur Lazarsfeld Expansion (BLE) which specifies dependencies between all subsets of terms has been used to identify productive clusters of items in a clustered data base environment. The successes of these models are unlikely to be accidental; it is of interest therefore to examine the similarities between the two models. The disadvantage of the BLE model is the exponential number of terms appearings in the full expression, while a truncated BLE system may produce negative probability values. The disadvantage of the tree dependence model is the restriction to dependencies between certain term pairs only and the exclusion of higher-order dependencies. A generalized term dependence model is introduced in this study which does not carry the disadvantages of either the tree dependence or the BLE models. Sample evaluation results are included to demonstrate the usefulness of the generalized system.
Volatility Cascade and Market Dynamics
Authors: Yoshi Fujiwara
Venue: Proceedings of the Fourth International Conference on Computational Intelligence and Multimedia Applications (2001)

Price fluctuations in speculative market dynamics have interesting statistical properties.As temporal ones, (I) vanishing autocorrelation of return, (ii) intermittency and long-memory in the magnitude of return, called volatility,(iii) self-similarity of volatilities for different time-scales ("volatility cascade ").These properties in strongly correlated regime from minutes to months are crucial for understanding market and tocontrol risk.First, it is briefly reviewed how one can characterize the statistical properties of such non-equilibrium nature.Second, adaptive agent models with opinion-epidemics and speculative bubbles are considered including Lux's stochastic model.The origin of volatility clustering and cascade might be understood as aggregate behavior of human speculations, and the dynamics might be regareded as a kind of on-off intermittency.
Synthesis of Multiple-Valued Decision Diagrams using Current-Mode CMOS Circuits
Authors: Mostafa Abd-El-Barr, Henry Fernandes
Venue: Proceedings of the Twenty Ninth IEEE International Symposium on Multiple-Valued Logic (1999)

In this paper, an algorithm for generating modular designs of Ordered Multiple Decision Diagrams (OMDDs) for Current-Mode CMOS Logic (CMCL) implementation is introduced. The OMDD structures for a set of twelve benchmark circuits from the LGSynth93 using radices ranging from r=2 to r=10 are generated and compared in terms of size and speed. It is observed that MODDs with radices r ? {2, 4, 8} result in the smallest area. They also achieve the smallest normalized (with respect to the AT2 measure for r = 2) AT2, where A is the area and T is the delay.
A Multilevel-Cell 32Mb Flash Memory
Authors: M. Bauer, R. Alexis, G. Atwood, B. Baltar, A. Fazio, K. Frary, M. Hensel, M. Ishac, J. Javanifard, M. Landgraf, D. Leak, K. Loe, D. Mills, P. Ruby, R. Rozman, S. Sweha, S. Talreja, K. Wojciechowski
Venue: Proceedings of the 30th IEEE International Symposium on Multiple-Valued Logic (2000)

A flash memory with multilevel cell significantly reduces the memory per-bit cost. A 32 MB multilevel-cell (MLC) flash memory storing two bits of data per cell achieves 32 MB memory storage capacity using 16 M flash memory cells. This 32 MB flash memory on a 0.6µm process has a 2.0x1.8µm2 flash cell. In MLC operation, the logical flash memory cell achieves two bits per cell using four possible states, defined by four flash cell threshold voltage ranges. The relationship between the threshold voltage ranges stored in the flash memory cell and the corresponding logic levels is shown in this paper, which also shows a plot of the four threshold voltage distributions, each with a separation range.
Uniform Multipaging Reduces to Paging
Authors: Vincenzo Liberatore
Venue:  (1997)

Multipaging is the paging problem when more than one page can be requested at each step. In the uniform cost model, a paging algorithm is charged for the number of pages loaded from disk to fast memory. In this note, we establish a general reduction from uniform multipaging to paging. As a consequence, we obtain the first strongly competitive randomized algorithm for uniform multipaging.
On the distortional post-buckling behaviour of rack-section cold-formed steel columns
Authors: L. C. Prola, D. Camotim
Venue: Proceedings of the sixth conference on Computational structures technology (2002)

The paper reports and discusses numerical (mostly) and experimental results dealing with the elastic distortional post-buckling behaviour of rack-section cold-formed steel columns, i.e., members acted by uniform compression. The numerical results are determined by means of spline finite analyses and incorporate the effect of initial geometrical imperfections with the critical (distortional) buckling mode shape. They include (i) post-buckling equilibrium paths and (ii) curves describing the evolution, along such paths, of the most relevant (ii1) displacement and stress longitudinal profiles and (ii2) cross-section stress distributions. In particular, results obtained revealed a non negligible post-buckling asymmetry, with respect to the "sign" of the cross-section distortion, an important and rather surprising feature which stems from differences in the flange-stiffener warping (resistance) behaviour. Moreover, the results presented also address how the column distortional post-buckling behaviour and strength is influenced by the local boundary conditions, namely (i) the wall element transverse edges rotational restraint and (ii) the end section warping restraint. Finally, an experimental investigation is also reported, which involves the testing of stub-columns with the end sections fully restrained against both transverse edge rotation and warping. The test set-up and procedure are briefly described and the most relevant results are displayed, discussed and compared with numerical ones.