ppxscal/embedding_network huggingface dataset:
Performance analysis of IEEE 802.11 MAC protocols in wireless LANs: Research Articles
Authors: Hongqiang Zhai, Younggoo Kwon, Yuguang Fang
Venue: Wireless Communications Mobile Computing (2004)

IEEE 802.11 MAC protocol is the de facto standard for wireless local area networks (LANs), and has also been implemented in many network simulation packages for wireless multi-hop ad hoc networks. However, it is well known that, as the number of active stations increases, the performance of IEEE 802.11 MAC in terms of delay and throughput degrades dramatically, especially when each station's load approaches its saturation state. To explore the inherent problems in this protocol, it is important to characterize the probability distribution of the packet service time at the MAC layer. In this paper, by modeling the exponential backoff process as a Markov chain, we can use the signal transfer function of the generalized state transition diagram to derive an approximate probability distribution of the MAC layer service time. We then present the discrete probability distribution for MAC layer packet service time, which is shown to accurately match the simulation data from network simulations. Based on the probability model for the MAC layer service time, we can analyze a few performance metrics of the wireless LAN and give better explanation to the performance degradation in delay and throughput at various traffic loads. Furthermore, we demonstrate that the exponential distribution is a good approximation model for the MAC layer service time for the queueing analysis, and the presented queueing models can accurately match the simulation data obtained from ns-2 when the arrival process at MAC layer is Poissonian. Copyright &copy; 2004 John Wiley & Sons, Ltd.
An Alternative Queuing Technique to Optimize the Performance of TDMA Based Mobile Communication Systems
Authors: I. Panoutsopoulos, S. Kotsopoulos, K. Ioannou, S. Louvros
Venue: Wireless Personal Communications: An International Journal (2004)

This paper analyses an alternative traffic queuing model for the quality of service (QoS) optimization in mobile communications systems. According to the proposed model, the queue of handover attempts is separated to each of the used transceivers of a base transceiver station that covers a particular area. Fixed channel assignment and TDMA are considered, while the proposed technique is compared to the classic queuing model. The comparison results show that the QoS of the proposed model is fully optimized, especially if large queue sizes are chosen.
Cross-Generalization: Learning Novel Classes from a Single Example by Feature Replacement
Authors: Evgeniy Bart, Shimon Ullman
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 1 - Volume 01 (2005)

We develop an object classification method that can learn a novel class from a single training example. In this method, experience with already learned classes is used to facilitate the learning of novel classes. Our classification scheme employs features that discriminate between class and non-class images. For a novel class, new features are derived by selecting features that proved useful for already learned classification tasks, and adapting these features to the new classification task. This adaptation is performed by replacing the features from already learned classes with similar features taken from the novel class. A single example of a novel class is sufficient to perform feature adaptation and achieve useful classification performance. Experiments demonstrate that the proposed algorithm can learn a novel class from a single training example, using 10 additional familiar classes. The performance is significantly improved compared to using no feature adaptation. The robustness of the proposed feature adaptation concept is demonstrated by similar performance gains across 107 widely varying object categories.
The Church-Rosser languages are the deterministic variants of the growing context-sensitive languages
Authors: Gundula Niemann, Friedrich Otto
Venue: Information and Computation (2005)

The growing context-sensitive languages have been classified through the shrinking two-pushdown automaton, the deterministic version of which characterizes the class of generalized Church-Rosser languages [Inform. Comput. 141 (1998) 1]. Exploiting this characterization we prove that the latter class coincides with the class of Church-Rosser languages that was introduced by McNaughton et al. [J. ACM 35 (1988) 324]. Based on this result several open problems of McNaughton et al. are solved. In addition, we show that shrinking two-pushdown automata and length-reducing two-pushdown automata are equivalent, both in the non-deterministic and the deterministic case, thus obtaining still another characterization of the growing context-sensitive languages and the Church-Rosser languages, respectively.
A multidimensional extension of Pascal's triangle
Authors: Edward A. Eaton
Venue: ACM SIGSMALL/PC Notes (1990)

I read with interest Thomas Byrne's article: "An Extension of Pascal's Triangle and Work concerning Binomial Expansion Coefficients" in the February 1990 issue. On page 28 Mr. Byrne states: "I was seeking a mechanism to generate multinomial expansion coefficients but this doesn't do it . . . Maybe a three dimensional extension will prove useful." The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
A Software Process Improvement Lifecycle Framework for the Medical Device Industry
Authors: F. McCaffery, D. McFall, P. Donnelly, F. G. Wilkie, R. Sterritt
Venue: Proceedings of the 12th IEEE International Conference and Workshops on Engineering of Computer-Based Systems (2005)

This paper describes a software process improvement (SPI) framework to ensure regulatory compliance for the software developed in medical devices. The software framework introduced here (known as MedeSPI ¿ Medical Devices Software Process Improvement) will address an opportunity to integrate the regulatory issues and process improvement mechanisms in order to achieve improved software processes.
High Altitude Platform mm-Wave Aperture Antenna Steering Solutions
Authors: M. H. Capstick, D. Grace
Venue: Wireless Personal Communications: An International Journal (2005)

This paper compares the performance and complexity of two methods of steering an array of aperture antennas on a high altitude platform for the provision of broadband fixed wireless access using cellular type frequency reuse. The first method is to steer all antennas individually to maintain the boresight at the required cell centre. The paper also presents a second method of compensating for aperture antenna pointing error due to lateral and vertical displacement of the platform from the nominal station using only four actuators plus a gimbal that can correct for roll, pitch and yaw of the platform. Results for signal strength, CIR and handovers are given for both scenarios and conclusions drawn.
IDENTIFYING HIGH-LEVEL UNIX TASKS
Authors: Russell J. Branaghan, James E. McDonald, Roger W. Schvaneveldt
Venue: ACM SIGCHI Bulletin (1991)

Task analysis (TA) in systems design has a number of goals, including identifying information needed by the user, knowledge and skills that the user needs, and potential errors that the user might make. However, a necessary precursor to TA is to determine what the important tasks are in the first place. This research is aimed at developing a methodology for identifying tasks in command-based human-computer systems. The following paragraphs delineate the motivation for the approach, as well as the general procedures in this methodology.
The meeting project at ICSI
Authors: Nelson Morgan, Don Baron, Jane Edwards, Dan Ellis, David Gelbart, Adam Janin, Thilo Pfau, Elizabeth Shriberg, Andreas Stolcke
Venue: Proceedings of the first international conference on Human language technology research (2001)

In collaboration with colleagues at UW, OGI, IBM, and SRI, we are developing technology to process spoken language from informal meetings. The work includes a substantial data collection and transcription effort, and has required a nontrivial degree of infrastructure development. We are undertaking this because the new task area provides a significant challenge to current HLT capabilities, while offering the promise of a wide range of potential applications. In this paper, we give our vision of the task, the challenges it represents, and the current state of our development, with particular attention to automatic transcription.
A context based storage system for mobile computing applications
Authors: Sharat Khungar, Jukka Riekki
Venue: ACM SIGMOBILE Mobile Computing and Communications Review (2005)

In this paper, we describe a novel context based storage system that use context to manage user data and make it available to him based on his situation. First, we examine several existing systems that use context with documents. Subsequently, a new storage system is presented that uses context to aid in the capture of and access to documents in mobile environment. We describe file browser and calendar applications that we have developed within our mobile computing infrastructure utilizing the features of context based storage. Novel features of our system include the access rights mechanism for data and support for group activity.
An interactive method for extracting grammar from programs
Authors: Rahul Jain, Sanjeev Kumar Aggarwal, Pankaj Jalote, Shiladitya Biswas
Venue: Software&mdash;Practice Experience (2004)

The grammar of the language in which some given code is written is essential for developing automated tools for maintenance, reengineering, and program analysis. Frequently grammar is available for a language but not for its variants that are implemented by various vendors and in which the given code may be written. In this work we address the problem of obtaining the grammar from source code, which can then be used for generating tools for the programs. We propose an incremental method for obtaining grammar for a particular language variant, from a set of programs written in the language variant and an approximate grammar &lpar;presumably of the standard language&rpar; with some user interaction. We also present the design of a tool for implementing this approach and our experience in working with grammars of C, C&plus;&plus; and COBOL. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Sponge: a case study in practice-based collaborative art research
Authors: Christopher L. Salter, Sha Xin Wei
Venue: Proceedings of the 5th conference on Creativity cognition (2005)

In this paper, we describe the origins, thematics, projects and practices of the art research collective Sponge. In particular, we focus on Sponge as a useful case study in transdisciplinary, collaborative practice-based research in creative art and design production and specifically, on Sponge as a unique example of a community of practice that spans artistic production, techno-scientific research, and critical studies. Issues essential to collaborative work practices such as shared language, construction of boundary objects, accommodation of differing epistemic cultures as well Sponge's thematic interest in performance, materiality and agency are examined in the context of several large scale artistic projects produced in the US, Canada and Europe. Finally, we examine the relationship between Sponge and the second author's Topological Media Lab in trying to come to terms with the differing scales and life cycles in partnering between the university-based research lab and the sphere of artistic and cultural production.
Trust, Identity, and the Effects of Voting Technologies on Voting Behavior
Authors: Anne-Marie Oostveen, Peter Van Den Besselaar
Venue: Social Science Computer Review (2005)

A model is described to explain the effect of e-voting technology on voting behavior and the outcome of a ballot. In the model, social identity and trust play a central role. After an initial and partial test, the article discusses directions for further research.
An analytical model for multi-tier internet services and its applications
Authors: Bhuvan Urgaonkar, Giovanni Pacifici, Prashant Shenoy, Mike Spreitzer, Asser Tantawi
Venue: Proceedings of the 2005 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2005)

Since many Internet applications employ a multi-tier architecture, in this paper, we focus on the problem of analytically modeling the behavior of such applications. We present a model based on a network of queues, where the queues represent different tiers of the application. Our model is sufficiently general to capture (i) the behavior of tiers with significantly different performance characteristics and (ii) application idiosyncrasies such as session-based workloads, concurrency limits, and caching at intermediate tiers. We validate our model using real multi-tier applications running on a Linux server cluster. Our experiments indicate that our model faithfully captures the performance of these applications for a number of workloads and configurations. For a variety of scenarios, including those with caching at one of the application tiers, the average response times predicted by our model were within the 95% confidence intervals of the observed average response times. Our experiments also demonstrate the utility of the model for dynamic capacity provisioning, performance prediction, bottleneck identification, and session policing. In one scenario, where the request arrival rate increased from less than 1500 to nearly 4200 requests/min, a dynamic provisioning technique employing our model was able to maintain response time targets by increasing the capacity of two of the application tiers by factors of 2 and 3.5, respectively.
Modelling of batch production systems using Petri nets with dynamic tokens
Authors: Ernesto López-Mellado, Norma Villanueva-Paredes, Hugo Almeyda-Canepa
Venue: Mathematics and Computers in Simulation (2005)

This article deals with the qualitative modelling of batch production plants. The approach held is Petri net based. First a definition of a three-level net formalism is presented; the formalism extends the Valk's approach of nets in nets in which the tokens are other nets; in this extension the lower level net handles symbolic tokens. Then a methodology for the modelling of batch processes is proposed; in this methodology the upper level describes the plant layout, the next level models an entity that goes with the batch through the plant and specifies the material and the process routes that the batch must follow, and the third level represents detailed treatments to perform into the process cells using specific equipment. The use of the modelling formalism is illustrated through an example dealing with the coordination of a batch manufacturing system.
An Object Detection System using Image Reconstruction with PCA
Authors: Luis Malagon-Borja, Olac Fuentes
Venue: Proceedings of the 2nd Canadian conference on Computer and Robot Vision (2005)

We present an object detection system that is applied to detecting pedestrians in still images, without assuming any a priori knowledge about the image. The system works as follows: In a first stage a classifier examines each location in the image at different scales. Then in a second stage the system tries to eliminate false detections based on heuristics. The classifier is based on the idea that Principal Components Analysis (PCA) can compress optimally only the kind of images that were used to compute the principal components (PCs), and that any other kind of images will not be compressed well using a few components. Thus the classifier performs separately the PCA from the positive examples and from the negative examples, when it needs to classify a new pattern it projects it into both sets of PCs and compares the reconstructions. The system is able to detect frontal and rear views of pedestrians, and usually can also detect side views of pedestrians despite not being trained for this task. Comparisons with other pedestrian detection systems are presented; our system has better performance in positive detection and in false detection rate.
Image-based search engine
Authors: Michael Marcus
Venue: Journal of Computing Sciences in Colleges (2004)

We are in the process of developing an image-based search engine, capable of using distributed computing techniques to locate a shape in a larger image, regardless of scale or orientation. On today's computers, it is common for mainstream commercial search engines to find images based on keywords. The final outcome of this project will allow people to locate pictures based on image information, not text. To that end, we have designed a fully functional image-based search system that performs edge comparisons at various orientations and scale using distributed processing, and generates match results based on percentage.
SCALLOP: A Highly Scalable Parallel Poisson Solver in Three Dimensions
Authors: Gregory T. Balls, Scott B. Baden, Phillip Colella
Venue: Proceedings of the 2003 ACM/IEEE conference on Supercomputing (2003)

SCALLOP is a highly scalable solver and library for elliptic partial differential equations on regular block-structured domains. SCALLOP avoids high communication overheads algorithmically by taking advantage of the locality properties inherent to solutions to elliptic PDEs. Communication costs are small, on the order of a few percent of the total running time on up to 1024 processors of NPACI's and NERSC's IBM Power-3 SP sytems. SCALLOP trades off numerical overheads against communication. These numerical overheads are independent of the number of processors for a wide range of problem sizes. SCALLOP is implicitly designed for infinite domain (free space) boundary conditions, but the algorithm can be reformulated to accommodate other boundary conditions. The SCALLOP library is built on top of the KeLP programming system and runs on a variety of platforms.
The lattice dimension of a graph
Authors: David Eppstein
Venue: European Journal of Combinatorics (2005)

We describe a polynomial time algorithm for, given an undirected graph G, finding the minimum dimension d such that G may be isometrically embedded into the d-dimensional integer lattice Zd.
"May we have class outside?": implementing service learning in a CS1 curriculum
Authors: Joseph Brian Adams, Erica Runkles
Venue: Journal of Computing Sciences in Colleges (2004)

While service-learning is becoming more common in college curriculums, it is still noticeably absent from many computer science programs. This paper describes the concept of service-learning and its implementation into a computer science course. It then describes a successful collaboration of service-learning between students in a CS I course and inmates at a local county prison.
PAD: A New Interactive Knowledge-Based Analog Design Approach
Authors: Danica Stefanovic, Maher Kayal, Marc Pastre
Venue: Analog Integrated Circuits and Signal Processing (2005)

This paper presents a new Procedural Analog Design tool called PAD. It is a chart-based design environment dedicated to the design of analog circuits aiming to optimize design and quality by finding good tradeoffs. This interactive tool allows step-by-step design of analog cells by using guidelines for each analog topology. Its interactive interface enables instantaneous visualization of design tradeoffs. At each step, the user modifies interactively one subset of design parameters and observes the effect on other circuit parameters. At the end, an optimized design is ready for simulation (verification and fine-tuning). The present version of PAD covers the design of basic analog structures (one transistor or groups of transistors) and the procedural design of transconductance amplifiers (OTAs) and different operational amplifier topologies. The basic analog structures' calculator embedded in PAD uses the complete set of equations of the EKV MOS model, which links the equations for weak and strong inversion in a continuous way [1, 2]. Furthermore, PAD provides a layout generator for matched substructures such as current mirrors, cascode stages and differential pairs.
Classes of Fastest Quaternary Linearly Independent Transformations
Authors: Bogdan J. Falkowski, Cheng Fu
Venue: Proceedings of the 35th International Symposium on Multiple-Valued Logic (2005)

In this paper, four classes of quaternary linearly independent transformations, which possess fastest forward and inverse transforms with the lowest computational cost have been presented. All the transform matrices are recursively defined and have consistent formulas relating forward and inverse matrices. Computational costs of the calculation for presented transforms have also been discussed.
DAGGER: A Novel Generic Methodology for FPGA Bitstream Generation and Its Software Tool Implementation
Authors: K. Siozios, G. Koutroumpezis, K. Tatas, D. Soudris, A. Thanailakis
Venue: Proceedings of the 19th IEEE International Parallel and Distributed Processing Symposium (IPDPS'05) - Workshop 3 - Volume 04 (2005)

A novel bitstream generation algorithm and its software implementation are introduced. Although this tool was developed for the configuration of AMDREL FPGA reconfigurable platform, it could be used to program any other compatible device. This tool is the only one known academic implementation for FPGA configuration with such features. Among them are the run-time-, partial- and dynamic-reconfiguration, the memory management, the bitstream compression and encryption, the read-back technique, the bitstream reallocation, the used low-power techniques as well as the Graphical User Interface.
A new distributed storage scheme for cluster video server
Authors: Xiaofei Liao, Hai Jin
Venue: Journal of Systems Architecture: the EUROMICRO Journal (2005)

For cluster video servers, it is very important to design a good distributed storage system with high performance. One of the important issues in designing a good distributed storage system is how to store multimedia data on many storage nodes. This issue includes two topics: the scheme of splitting an entire file into many clips, and the storage of these clips on many nodes. We have designed a new multimedia data storage scheme for cluster video server. In the new system, a novel multimedia file splitting scheme, named Owl, and a clips striping scheme have been proposed. In contrast with traditional media data splitting schemes based on fixed space length and constant time length, Owl is addressed with the consideration of spatial and temporal information. This scheme Owl has universality for every media format encoded based on time and makes cluster video servers work efficiently. Besides, the scheme Owl is feasible and easy to implement. With the data splitting scheme and the clips striping scheme, cluster video servers have good performance.