ppxscal/embedding_network huggingface dataset:
Design and evaluation of multichannel multirate wireless networks
Authors: Niranjan Niranjan, Sugam Pandey, Aura Ganz
Venue: Mobile Networks and Applications (2006)

In a multirate wireless network, low data rate nodes consume proportionately more channel resources than high data rate nodes, resulting in low overall network performance. The use of multiple non-overlapping frequency channels in multirate wireless networks can overcome the performance degradation by having nodes communicate on different channels based on their data rates. However, no effort has been invested to utilize the multiple channels for a multirate wireless network. In this paper, we introduce the Data Rate Adaptive Channel Assignment (DR-CA) algorithm for a multichannel multirate single-hop wireless network to provide higher network throughput and network efficiency. The main idea is to assign links having same or comparable data rates on the same channel to minimize the wastage of channel resources due to interference between high data links and low data rate links. We also design a new Intermediary Multichannel Layer (IML) which resides between network layer and link layer, at which we implement the DR-CA algorithm. The IML design requires no modifications to the underlying MAC layer and upper layers of the network stack. To evaluate the proposed algorithm we define new performance metrics-channel efficiency and network efficiency for a multichannel multirate wireless network. Using OPNET simulations, we show that the multichannel enhancement using our proposed algorithm provides significant performance improvement in terms of network throughput, channel efficiency, and network efficiency over existing approaches in multirate wireless networks. Under heavy load condition, the network efficiency using DR-CA algorithm reaches 90% of the maximum limit. To the best of our knowledge, this is the first work to utilize the benefits of multiple channels in the multirate wireless network environment.
Role of the Right and Left Hemispheres in Recovery of Function during Treatment of Intention in Aphasia
Authors: Bruce Crosson, Anna Bacon Moore, Kaundinya Gopinath, Keith D. White, Christina E. Wierenga, Megan E. Gaiefsky, Katherine S. Fabrizio, Kyung K. Peck, David Soltysik, Christina Milsted, Richard W. Briggs, Tim W. Conway, Leslie J. Gonzalez Rothi
Venue: Journal of Cognitive Neuroscience (2005)

Two patients with residual nonf luent aphasia after ischemic stroke received an intention treatment that was designed to shift intention and language production mechanisms from the frontal lobe of the damaged left hemisphere to the right frontal lobe. Consistent with experimental hypotheses, the first patient showed improvement on the intention treatment but not on a similar attention treatment. In addition, in keeping with experimental hypotheses, the patient showed a shift of activity to right presupplementary motor area and the right lateral frontal lobe from pre- to post-intention treatment functional magnetic resonance imaging (fMRI) of language production. In contrast, the second patient showed improvement on both the intention and attention treatments. During pre-treatment fMRI, she already showed lateralization of intention and language production mechanisms to the right hemisphere that continued into post-intention treatment imaging. From pre- to post-treatment fMRI of language production, both patients demonstrated increased activity in the posterior perisylvian cortex, although this activity was lateralized to left-hemisphere language areas in the second but not the first patient. The fact that the first patient's lesion encompassed almost all of the dominant basal ganglia and thalamus whereas the second patient's lesion spared these structures suggests that the dominant basal ganglia could play a role in spontaneous reorganization of language production functions to the right hemisphere. Implications regarding the theoretical framework for the intention treatment are discussed.
Collaborative learning through computer-mediated argumentation
Authors: A. L. Veerman, J. E. B. Andriessen, G. Kanselaar
Venue: Proceedings of the 1999 conference on Computer support for collaborative learning (1999)

This article reports on three studies that involved undergraduate students collaboratively working on authentic discussion tasks in synchronous and asynchronous Computer Mediated Communication systems (Netmeeting, Belv&eacute;d&egrave;re, Allaire Forums). The purposes of the assignments were respectively to develop insight and understanding in a theoretical framework, to co-construct meaningful didactics for a computer based training program and to develop insight and understanding in educational theories in relation to technology. To examine whether the use of the CMC systems could meet these ends, students' dialogues are characterised in terms of their constructive and argumentative contributions and by their focus on the meaning and application of concepts. In addition, we compare different forms of support, from peer coaching synchronous discussions, offering graphical support at the interface to reflective moderation in asynchronous discussions. Although we compare different systems and assignments, the interplay between focused argumentation and constructive contributions allows us to analyse and compare interaction and learning in different CMC systems, with and without forms of pedagogical support.
Context-Aware Personalization in Pervasive Communications
Authors: Yuping Yang, M. Howard Williams, Rob Pooley, Rick Dewar
Venue: Proceedings of the IEEE International Conference on e-Business Engineering (2006)

This paper gives a brief overview of the Daidalos Personalization architecture, the aim of which is to improve user experience by personalizing services, including third-party services and Daidalos enabling services in pervasive computing environments. Personalization plays a paramount role in service composition, elucidation of user preferences and reservation of resources for users, where user privacy has been well considered. In this paper, we discuss how personalization is exploited and investigated to give a completely personalized service offering to a user at any time, any where.
Emergency department simulations: medicine for building effective models
Authors: Carley J. Jurishica
Venue: Proceedings of the 37th conference on Winter simulation (2005)

This paper will discuss proven practices for developing Emergency Department (ED) simulations based on recent project success. From human decisions to political agendas, an ED is filled with unpredictable elements, making it a difficult environment to model. However, the key decision-making information that will be uncovered from a study is worth the effort. This paper will thoroughly analyze each step of a typical ED simulation project, identifying key areas of focus and tips for success. Defining the objective, process map, scenarios, outputs and animation requirements are the first steps. A system for gathering the ED data will be discussed, as well as advice for the verification and validation phases. Finally, the presentation of the findings will be analyzed. No part an ED simulation project should be discounted. This paper will stress dependency of each phase on the successful outcome of the entire project.
ShibGrid: Shibboleth Access for the UK National Grid Service
Authors: David Spence, Neil Geddes, Jens Jensen, Andrew Richards, Matthew Viljoen, Andrew Martin, Matthew Dovey, Mark Norman, Kang Tang, Anne Trefethen, David Wallom, Rob Allan, David Meredith
Venue: Proceedings of the Second IEEE International Conference on e-Science and Grid Computing (2006)

This paper presents work undertaken to integrate the future UK national Shibboleth infrastructure with the UK's National Grid Service (NGS). Our work, ShibGrid, provides both transparent authentication for portal based Grid access and a credential transformation service for users of other Grid access methods. The ShibGrid support for portal-based transparent Grid authentication is provided as a set of standards-based drop-in modules which can be used with any project portal as well as the NGS project in which they are initially deployed. The ShibGrid architecture requires no changes to the UK national Shibboleth authentication infrastructure or the NGS security infrastructure and provides access for users both with and without UK e-Science certificates. In addition to presenting both the architecture of Shib- Grid and its implementation, we additionally place the ShibGrid project within the context of other efforts to integrate Shibboleth with Grids.
Maintainability of the kernels of open-source operating systems: A comparison of Linux with FreeBSD, NetBSD, and OpenBSD
Authors: Liguo Yu, Stephen R. Schach, Kai Chen, Gillian Z. Heller, Jeff Offutt
Venue: Journal of Systems and Software (2006)

We compared and contrasted the maintainability of four open-source operating systems: Linux, FreeBSD, NetBSD, and OpenBSD. We used our categorization of common coupling in kernel-based software to highlight future maintenance problems. An unsafe definition is a definition of a global variable that can affect a kernel module if that definition is changed. For each operating system we determined a number of measures, including the number of global variables, the number of instances of global variables in the kernel and overall, as well as the number of unsafe definitions in the kernel and overall. We also computed the value of each our measures per kernel KLOC and per KLOC overall. For every measure and every ratio, Linux compared unfavorably with FreeBSD, NetBSD, and OpenBSD. Accordingly, we are concerned about the future maintainability of Linux.
Grid Support for HLA-Based Collaborative Environment for Vascular Reconstruction
Authors: Katarzyna Rycerz, Marian Bubak, Maciej Malawski, Peter Sloot
Venue: Proceedings of the Second IEEE International Conference on e-Science and Grid Computing (2006)

Collaborative environments where users can interact with running simulations are an important aspect of e- Science. To achieve efficient execution of High Level Architecture (HLA)-based collaborative environments on the Grid, we introduce a Grid HLA Management System (GHLAM) for their management. This is done by introducing migration and monitoring mechanisms for such applications. In this paper we present how G-HLAM can be applied to the collaborative environment supporting surgeons with simulations of vascular reconstruction, using distributed federations on the Grid for the communication among simulation and visualization components.
A Modified Particle Filter for Simultaneous Localization and Mapping
Authors: N. M. Kwok, A. B. Rad
Venue: Journal of Intelligent and Robotic Systems (2006)

The implementation of a particle filter (PF) for vision-based bearing-only simultaneous localization and mapping (SLAM) of a mobile robot in an unstructured indoor environment is presented in this paper. Variations, using techniques from the genetic algorithm (GA), to standard PF procedures are proposed to alleviate the sample impoverishment problem. A monochrome CCD camera mounted on the robot is used as the measuring device and a measure on the image quality is incorporated into data association and PF update. Since the bearing-only measurement does not contain range information, we add a pseudo range to the measurement during landmark initialization as a hypothesised pair and the non-promising landmark is removed by a map management strategy. Simulation and experimental results from an implementation using real-life data acquired from a Pioneer robot are included to demonstrate the effectiveness of our approach.
Self-Stabilizing Distributed Queuing
Authors: Srikanta Tirthapura, Maurice Herlihy
Venue: IEEE Transactions on Parallel and Distributed Systems (2006)

Distributed queuing is a fundamental coordination problem arising in a variety of applications, including distributed shared memory, distributed directories, and totally ordered multicast. A distributed queue can be used to order events, user operations, or messages in a distributed system. This paper presents a new self-stabilizing distributed queuing protocol. This protocol adds self-stabilizing actions to the arrow distributed queuing protocol, a simple path-reversal protocol that runs on a spanning tree of the network. We present a proof that the protocol stabilizes to a stable state irrespective of the (perhaps faulty) initial state, and also present an analysis of the time until convergence. The self-stabilizing queuing protocol is structured as a layer that runs on top of any self-stabilizing spanning tree protocol. This additional queuing layer is guaranteed to stabilize in time bounded by a constant number of message delays across an edge, thus establishing that the stabilization time for distributed queuing is not much more than the stabilization time for spanning tree maintenance. The key idea in our protocol is that the global predicate defining the legality of a protocol state can be written as the conjunction of many purely local predicates, one for each edge of the spanning tree.
Efficient generation of cycle time-throughput curves through simulation and metamodeling
Authors: Feng Yang, Bruce E. Ankenman, Barry L. Nelson
Venue: Proceedings of the 37th conference on Winter simulation (2005)

A cycle time-throughput (CT-TH) curve plays an important role in strategic planning for manufacturing systems. In this research, we seek to quantify the relationship of the moments and percentiles of cycle time to throughput rate via simulation experiments. The estimation of CT-TH moment curves is based on a nonlinear regression metamodel supported by queueing theory, and the adequacy of the model has been proved through our numerical experiments. Utilizing the estimated moment curves of cycle time, we proposed to estimate the CT-TH percentile curves in an indirect method assuming that the underlying distribution of cycle time is a generalized gamma, a highly flexible distribution. More specifically, we fit metamodels for the first three CT-TH moment curves throughout the throughput range of interest, determine the parameters of the generalized gamma by matching moments, and then obtain percentiles by inverting the distribution. To insure efficiency and control estimation error, simulation experiments are sequentially built up to optimize some design criterion.
A versatile programming model for dynamic task scheduling on cluster computers
Authors: Sotirios G. Ziavras
Venue:  (2005)

This dissertation studies the development of application programs for parallel and distributed computer systems, especially PC clusters. A methodology is proposed to increase the efficiency of code development, the productivity of programmers and enhance performance of executing the developed programs on PC clusters while facilitating improvement of scalability and code portability of these programs. A new programming model, named the Super-Programming Model (SPM), is created. Programs are developed assuming an instruction set architecture comprised of Super-Instructions (SIs). SPM models the target system as a large Virtual Machine (VM); VM contains functional units which are underlain with sub-computer systems and SIs are implemented with codes. When these functional units execute SIs, their codes will run on member computers to perform the corresponding operations. This approach resembles the process of designing instruction sets for microprocessors but the VM employs much coarser instructions and data structures. SIs use Super-Data Blocks (SDBs) as their operands. Each SI is assigned to a single member computer and is indivisible (i.e., its implementation is not interrupted for I/O). SIs have predictable execution times because SDB sizes are limited by predefined thresholds. These qualities of SIs help dynamic load balancing. Employing software to implement instructions makes this approach more flexible. The developed programs fit to architectures of cluster systems better. SPM provides mechanisms, such as dynamic load balancing, to assure the efficient execution of programs. The vast majority of current programming models lack such mechanisms for distributed environments that suffer from long communication latencies. Since SPM employs coarse-grain tasks, the overall management overhead is small. SDB access can often overlap the execution of other SIs; a cache system further decreases average memory latencies. Since all SDBs are virtual entities, with the runtime system support, they can be accessed in parallel and efficiently minimizes additional constraints to parallelism from underlying computer systems. In this research, a reference implementation of VM has been developed. A performance estimation model is developed that takes these features into account. Finally, the definition of scalability for parallel/distributed processing is refined to represent a multi-dimensional entity. Sample cases are analyzed.
Is 1 noun worth 2 adjectives?: measuring relative feature utility
Authors: Robert M. Losee
Venue: Information Processing and Management: an International Journal (2006)

Are two adjectives worth the same as a single noun when documents are ordered based on decreasing topicality? We propose an easy to interpret single number Relative Feature Utility (RFU) measure of the relative worth of using specific linguistic or non-linguistic features or sets of features in computational systems that order or filter media, such as information retrieval and classification systems. This measure allows one to make easily interpreted claims about the relative utility of features such as parts-of-speech, term suffixes, phrases vs. single terms, annotations, hyperlinks, citations, index terms, and metadata when ordering natural language text or other media. Data is provided for the RFU for stemming characteristics, part-of-speech tags, and phrase lengths, as well as retrieval characteristics and procedures. Using this linear measure of the relative utility of features makes available a wide range of cost-benefit analyses and decision theoretic techniques, allowing the study of whether or not to use many different kinds of representational information or tagging systems, and for the design of indexing and metadata systems. Some characteristics of natural languages used in the spectrum from softer to harder sciences, as well as medical terminology, are studied.
Video distribution with edge stations and Wi-Fi delivery networks
Authors: Min-You Wu, Wei Shu
Venue: Proceedings of the 2003 International Conference on Multimedia and Expo - Volume 1 (2003)

A video distribution architecture with edge stations and Wi-Fi delivery networks as connection to residential homes is described in this paper. An edge station is configurable and controllable by a central server. It is placed in the access point of Wi-Fi networks and has multiple usages. Due to its large storage space it can be used as a mirroring/caching proxy for continuous media. Replicating popular video contents in many small mirroring sites can significantly reduce the network bandwidth requirement. When this structure is used with a cable or hybrid fiber/coax (HFC) network, it turns to be a hybrid fiber/coaxAVi-Fi (HFCW) structure, particularly suitable for video-on-demand (VoD) applications. There are many advantages of this architecture. First, the central server load and network traffic can be reduced to a small percentage. Second, the response time of most video playing requests can be significantly reduced. Third, true VoD can possibly be provided with a one-way cable system. Finally, noise from STBs (set-top boxes) is absorbed by the edge station in a two-way cable system.
Video streaming over overlaid bluetooth piconets (OBP)
Authors: Sewook Jung, Alexander Chang, Mario Gerla
Venue: Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation characterization (2006)

In a large scale Bluetooth network, scatternet has been regarded as the only interconnection method among piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. Overlaid Bluetooth Piconets (OBP) interconnects piconets and forms a virtual scatternet. This demo shows the possibility of using OBP instead of Scatternet for Video Streaming.
RCT: A Self-Adaptive Overlay for Efficient Computational Resource Discovery in Grid Systems
Authors: Hailong Sun, Jinpeng Huai, Gongwei Fu, Yunhao Liu
Venue: Proceedings of the Second IEEE International Conference on e-Science and Grid Computing (2006)

Computational resource discovery is of great importance in grid environments. Existing approaches do not consider the characteristics of application resource requirements. We propose, Resource Category Tree (RCT), which organizes computational resources based on their characteristics represented by primary attributes (PA). RCT adopts a structure of AVL tree, with each node representing a specific range of PA values. Though RCT adopts a hierarchical structure, it does not require nodes in higher levels maintain more information than those in lower levels, which makes RCT highly scalable. RCT is featured by self-organization, load-aware self-adaptation and fault tolerance. Based on RCT, commonly used queries, such as range queries and multi-attribute queries, are well supported. We conduct performance evaluations through comprehensive simulations.
On Store Placement for Response Time Minimization in Parallel Disks
Authors: Akshat Verma, Ashok Anand
Venue: Proceedings of the 26th IEEE International Conference on Distributed Computing Systems (2006)

We investigate the placement of N enterprise data-stores (e.g., database tables, application data) across an array of disks with the aim of minimizing the response time averaged over all served requests, while balancing the load evenly across all the disks in the parallel disk array. Incorporating the non-FCFS serving discipline and non work-conserving nature of disk drives in formulation of the placement problem is difficult and current placement strategies do not take them into account. We present a novel formulation of the placement problem to incorporate these crucial features and identify the runlength of requests accessing a store as the most important criterion for placing the stores. We use these insights to design a fast (running time of N logN) placement algorithm that is optimal under the assumption that transfer times are small. Comprehensive experimental studies establish the efficacy of the proposed algorithm under a wide variety of workloads with the proposed algorithm reducing the response time for real storage traces by more than a factor of 2 under heterogeneous workload scenarios.
Cross-Layer Design for Multimedia Delivery over Wireless Networks
Authors: Dalei Wu, Song Ci, Haohong Wang
Venue: Proceedings of the Eighth IEEE International Symposium on Multimedia (2006)

Video summarization has gained increased popularity in the emerging multimedia and communications applications. However, very limited work has been conducted to address the transmission problem of video summary frames. In this paper, we propose a cross-layer optimization framework for delivering video summaries over wireless networks. Within a rate-distortion theoretical framework, the source coding, allowable retransmission, and adaptive modulation and coding have been jointly optimized, which reflects the joint selection of parameters in physical, data link and application layers. The goal here is to achieve the best video quality and content coverage from the received summary frames as well as meet the delay constraint. In this paper, this problem is formulated and solved by using Lagrangian relaxation and dynamic programming. Simulation results indicate the effectiveness and efficiency of the proposed optimization framework, especially when the delay budget imposed by the upper layer applications is small, where more than 12% distortion gain can be achieved.