ppxscal/embedding_network huggingface dataset:
An Enhanced Memory Address Mapping Scheme for Improved Memory Access Performance of 2-D DWT Processing Systems
Authors: Sze-Wei Lee, Soon-Chieh Lim
Venue: Journal of VLSI Signal Processing Systems (2007)

The implementation of the memory for storing image and transform coefficients in 2-D DWT processing systems using the more cost-effective external memory module such as DDR DRAM is shown to suffer from effective memory bandwidth which is significantly lower than the memory system peak bandwidth if the conventional direct logical-to-physical memory address mapping is adopted. The low effective memory bandwidth is caused by the high level of memory overhead cycle occurrence which is in turn is closely related to the logical memory access patterns of 2-D DWT processes. The problem becomes even more severe for the 2-D DWT processing of video. An analysis on the logical memory access patterns of multi-level 2-D DWT is carried out and an enhanced logical-to-physical memory mapping scheme which minimizes the occurrence of memory overhead cycles is proposed. The proposed scheme is simulated and its performance in terms of effective memory access bandwidth is evaluated and compared with the conventional direct mapping scheme.
Distributed resource allocation in contention-based wireless networks
Authors: Robin Kravets
Venue:  (2006)

Due to the limited bandwidth in wireless networks, careful resource allocation schemes must be used to allocate bandwidth to applications. There are two typical types of applications in wireless networks that require resource allocation: soft realtime applications and best effort applications. While soft realtime applications require QoS support for effective bandwidth utilization, best effort applications can adapt to changes in bandwidth and are more concerned about network utilization. Due to this difference in application requirements, intelligent resource allocation schemes must be used to provide the desired amount of resources to realtime flows while at the same time allocate the rest of the bandwidth to best effort flows efficiently. The goal of this thesis is to explore two different methods to support such intelligent distributed resource allocation in contention-based wireless networks. The first method uses signaling between nodes to coordinate resource allocation. The benefit of this signaling approach is that it does not require any specialized MAC layer and is based on existing scheduling algorithms used in current MAC layer protocols such as IEEE 802.11. Due to the shared nature of wireless medium, a signaling approach must effectively coordinate resource allocation among interfering nodes. This thesis addresses two challenging aspects of designing such a signaling approach: efficient signaling and accurate estimation of available bandwidth.The second method that relies on advanced MAC layer scheduling and MAC layer resource monitoring. Such a MAC layer approach is able to achieve low message overhead and can easily adapt to the dynamics of the network. For the MAC layer approach, this thesis includes four novel MAC layer scheduling algorithms based on dynamic contention window control: DDA for delay assurance to realtime traffic, DBA for throughput assurance to realtime traffic, BEP for rate policing of best effort traffic and GCA for flexible and efficient bandwidth allocation of best effort traffic. This thesis also describes a novel framework, QPART, that provides reactive admission control for a MAC layer approach. All these schemes are fully distributed and can support a variety of resource allocation policies without requiring communications among neighboring nodes.
Not quite NFS, soft cache consistency for NFS
Authors: Rick Macklem
Venue: Proceedings of the USENIX Winter 1994 Technical Conference on USENIX Winter 1994 Technical Conference (1994)

There are some constraints inherent in the NFSTM∈ protocol that result in performance limitations for high performance workstation environments. This paper discusses an NFS-like protocol named Not Quite NFS (NQNFS), designed to address some of these limitations. This protocol provides full cache consistency during normal operation, while permitting more effective client-side caching in an effort to improve performance. There are also a variety of minor protocol changes, in order to resolve various NFS issues. The emphasis is on observed performance of a preliminary implementation of the protocol, in order to show how well this design works and to suggest possible areas for further improvement.
Information Extraction from Web Pages Using Presentation Regularities and Domain Knowledge
Authors: Srinivas Vadrevu, Fatih Gelgi, Hasan Davulcu
Venue: World Wide Web (2007)

World Wide Web is transforming itself into the largest information resource making the process of information extraction (IE) from Web an important and challenging problem. In this paper, we present an automated IE system that is domain independent and that can automatically transform a given Web page into a semi-structured hierarchical document using presentation regularities. The resulting documents are weakly annotated in the sense that they might contain many incorrect annotations and missing labels. We also describe how to improve the quality of weakly annotated data by using domain knowledge in terms of a statistical domain model. We demonstrate that such system can recover from ambiguities in the presentation and boost the overall accuracy of a base information extractor by up to 20%. Our experimental evaluations with TAP data, computer science department Web sites, and RoadRunner document sets indicate that our algorithms can scale up to very large data sets.
Discrete Hartley transform based multicarrier modulation
Authors: Chin-Liang Wang
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 05 (2000)

This paper presents a real-valued discrete multicarrier modulation approach that is based on the use of the discrete Hartley transform (DHT) and its inverse (IDHT) to perform the modulation and demodulation operations. Since the DHT and IDHT definitions are identical, we can use the same hardware or program to implement the modulator and demodulator of the proposed multicarrier method. As compared to the complex-valued discrete Fourier transform based multicarrier modulation method, the proposed one achieves the same transmission performance with reduced computational complexity and implementation cost.
Towards building a conflict-free mobile distributed file system: Research Articles
Authors: Azzedine Boukerche, Raed A. Al-Shaikh
Venue: Concurrency and Computation: Practice Experience (2007)

The rising demand for mobile computing has created a need for an improved file system that supports mobile clients. Current file systems with support for mobility provide availability through file replicas that are cached at the client side. However, mobile clients may experience different obstacles with regards to the local cache, such as the limited network bandwidth, the intermittent connection, and serious conflicts when synchronizing back to the server. In this paper, we propose a novel mobile distributed file system design, which provides high availability and reliable storage for files and guarantees that file operations are executed regardless of concurrency and failure issues. The design is intended to fit mobile clients (e.g. PDAs and cell phones) that have limited storage space and cannot store all of the data they need, and yet require access to these data at all times. We adopt a server-side caching in order to guarantee sufficient caching space to all mobile clients, and to ensure the availability of files in the case of clients' failures. We present our algorithm, describe its implementation, simulate its high availability functions, and report on its performance evaluation using a cluster of workstations. Our simulation results indicate clearly that our algorithm exhibits a significant degree of automation and conflict-free mobile file system. Copyright &copy; 2007 John Wiley & Sons, Ltd.
A tracer metric numerical model for predicting tortuosity factors in three-dimensional porous tissue scaffolds
Authors: B. Starly, E. Yildirim, W. Sun
Venue: Computer Methods and Programs in Biomedicine (2007)

One of the critical functions of a tissue-engineered construct is to be able to provide adequate nutrient and oxygen supply into the interior of the construct. An insufficient supply will lead to slower cellular proliferation rates and eventual apoptosis. The supply of the nutrients is largely governed by the transport properties of the construct which in turn is dependent on the porosity, tortuosity and surface chemistry of the tissue construct. The design and fabrication of scaffolds with tailored properties is thus a crucial step in the growth of tissue within their host environment. This paper discusses the development of a numerical characterization technique to measure the three-dimensional tortuosity factors for any given interconnected porous design. Tortuosity factors are obtained in the three orthogonal principal directions for several candidate unit cell architectures. The proposed numerical technique has been validated with models of known tortuosity. The developed technique will provide a basis for the study of transport properties of the designed scaffold and its effect on cellular function and response through the development of dynamic culture bioreactors.
A wavelet-tree image coding system with efficient memory utilization
Authors: Y. Andreopoulos
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2001. on IEEE International Conference - Volume 03 (2001)

This paper describes an efficient implementation of an image coding system based on the independent wavelet-tree coding concept. The system consists of a transform and a (de)coding engine that operate in a pipelined fashion. The main focus of this paper is on the encoding part since, due to the system architecture, the decoder has identical memory utilization. Experimental results prove that the proposed system achieves comparable coding performance to the state-of-the-art, while it localizes the memory accesses to small memory modules and uses minimal computational resources.
Multicommodity demand flow in a tree and packing integer programs
Authors: Chandra Chekuri, Marcelo Mydlarz, F. Bruce Shepherd
Venue: ACM Transactions on Algorithms (TALG) (2007)

We consider requests for capacity in a given tree network T &equals; (V, E) where each edge e of the tree has some integer capacity ue. Each request f is a node pair with an integer demand df and a profit wf which is obtained if the request is satisfied. The objective is to find a set of demands that can be feasibly routed in the tree and which provides a maximum profit. This generalizes well-known problems, including the knapsack and b-matching problems. When all demands are 1, we have the integer multicommodity flow problem. Garg et al. [1997] had shown that this problem is NP-hard and gave a 2-approximation algorithm for the cardinality case (all profits are 1) via a primal-dual algorithm. Our main result establishes that the integrality gap of the natural linear programming relaxation is at most 4 for the case of arbitrary profits. Our proof is based on coloring paths on trees and this has other applications for wavelength assignment in optical network routing. We then consider the problem with arbitrary demands. When the maximum demand dmax is at most the minimum edge capacity umin, we show that the integrality gap of the LP is at most 48. This result is obtained by showing that the integrality gap for the demand version of such a problem is at most 11.542 times that for the unit-demand case. We use techniques of Kolliopoulos and Stein [2004, 2001] to obtain this. We also obtain, via this method, improved algorithms for line and ring networks. Applications and connections to other combinatorial problems are discussed.
Thread Verification - An Experience Report
Authors: Robert P. Cook
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2007)

The paper details the author's thread verification experiences with four applications: Linux kernel code, the Red Hat Linux POSIX Thread library, a portable PThread library, which was developed by the author for NASA, and a HandyChecker prototype. Based on the author's experiences, the paper concludes with a list of challenges for the verification community.
Vertex partitions and maximum degenerate subgraphs
Authors: Martín Matamala
Venue: Journal of Graph Theory (2007)

Let G be a graph with maximum degree d&ge; 3 and &omega;(G)&le; d, where &omega;(G) is the clique number of the graph G. Let p1 and p2 be two positive integers such that d&thinsp;=&thinsp;p1&thinsp;+&thinsp;p2. In this work, we prove that G has a vertex partition S1, S2 such that G[S1] is a <und>maximum order</und> (p1-1)-degenerate subgraph of G and G[S2] is a (p2-1)-degenerate subgraph, where G[Si] denotes the graph induced by the set Si in G, for i&thinsp;=&thinsp;1,2. On one hand, by using a degree-equilibrating process our result implies a result of Bollobas and Marvel [1]: for every graph G of maximum degree d&ge; 3 and &omega;(G)&le; d, and for every p1 and p2 positive integers such that d&thinsp;=&thinsp;p1&thinsp;+&thinsp;p2, the graph G has a partition S1,S2 such that for i&thinsp;=&thinsp;1,2, &Delta;(G[Si])&le; pi and G[Si] is (pi-1)-degenerate. On the other hand, our result refines the following result of Catlin in [2]: every graph G of maximum degree d&ge; 3 has a partition S1,S2 such that S1 is a maximum independent set and &omega;(G[S2])&le; d-1; it also refines a result of Catlin and Lai [3]: every graph G of maximum degree d&ge; 3 has a partition S1,S2 such that S1 is a maximum size set with G[S1] acyclic and &omega;(G[S2])&le; d-2. The cases d&thinsp;=&thinsp;3, (d,p1)&thinsp;=&thinsp;(4,1) and (d,p1)&thinsp;=&thinsp;(4,2) were proved by Catlin and Lai [3]. &copy; 2007 Wiley Periodicals, Inc. J Graph Theory 55: 227&ndash;232, 2007
Mechanical Impedance of the Hand Holding a Spherical Tool at Threshold and Suprathreshold Stimulation Levels
Authors: Ali Israr, Seungmoon Choi, Hong Z. Tan
Venue: Proceedings of the Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (2007)

We report mechanical impedance of the hand for sinusoidal stimulation at the threshold and suprathreshold levels in the frequency range of 10-500 Hz delivered through a ball-shaped interface. The participants held the ball mounted on a minishaker in a way similar to that of holding a ball interface of a force-feedback device. A minishaker excited the ball in the vertical direction, resulting in vibrations on the skin of the hand in mostly the tangential direction. The position detection threshold curve was similar to that measured earlier using a stylus in the pen-hold posture, but the force detection threshold curve and the mechanical impedance was shifted upwards in the high frequency region. The mechanical impedance at the threshold and suprathreshold levels were essentially the same, indicating that skin characteristics do not change in the dynamic range of tactual perception for the same tool-holding posture.
Towards Self-organizing Virtual Macro Sensors
Authors: Nicola Bicocchi, Marco Mamei, Franco Zambonelli
Venue: Proceedings of the First International Conference on Self-Adaptive and Self-Organizing Systems (2007)

The future mass deployment of pervasive and dense sensor network infrastructures calls for proper mechanisms to enable extracting general-purpose data from them at limited costs and in a compact way. The approach presented in this paper relies on a simple algorithm to let a sensor network self-organize a virtual partitioning in correspondence of spatial regions characterized by similar sensed patterns, and to let distributed aggregation of sensorial data take place on a per-region basis. This makes it possible to perceive the network as if it were composed of a limited number of virtual macro sensors, a feature which promises to be very suitable for a number of incoming usage scenarios.
Language model acquisition from a text corpus for speech understanding
Authors: T. Matsuoka, R. Hasson, M. Barlow, S. Furui
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 01 (1996)

Speech understanding can be viewed as a problem of translating the input natural language of speech recognition results into an output semantic language. This paper describes automatic acquisition of a language model for translating natural language into semantic language from a text corpus using a stochastic method. The method estimates the co-occurrence probabilities of input and output grammar rules as a translation language model. Since the amount of text is limited, estimating a reliable language model is difficult. Therefore, we propose a method of concisely modeling input and output grammars in order to estimate a reliable translation model. Our method is shown to be effective by experiments using the ARPA ATIS task.
Secure and private service discovery in pervasive computing environments
Authors: Matt W. Mutka
Venue:  (2006)

Service discovery is an essential element in pervasive computing environments to minimize administrative overhead. It enables devices and network services to properly discover, configure, and then communicate with each other. Much research on service discovery has been conducted, but most protocols are not designed with security and privacy support. Therefore, services may be discovered and used by anyone and subject to attacks. Directly applying the existing security and privacy solutions, however, may not work simply because the environments change. This research addressed four areas of secure service discovery design, namely, unfamiliar environments, authentication, personal privacy, and its application for entity authentication in pervasive computing. The research resulted in a comprehensive survey, identification of essential secure and private service discovery issues, and novel design for convenient, secure, and private service discovery. Our initial design of secure and private service discovery protocols targeted public environments. Proxy-based service discovery models were proposed to facilitate both mobile clients and services for secure and private service access and sharing. Then, we addressed a critical authentication issue in pervasive service discovery: involvement of necessary and proper users and service providers in a discovery session. We proposed a prudent service discovery model for users and service providers to establish mutual trust. The model also automates authentication processes. Therefore, users do not need to memorize the relationship among network services, service providers, and credentials. Next, we identified a difficult privacy challenge and expressed it as a "chicken-and-egg problem": both users and service providers want the other parties to expose sensitive information first. We proposed a progressive and probabilistic approach to protect privacy while achieving security and good usability at the same time. Our progressive exposure approach enables partial exposure. As a result, we provide an additional exposure choice besides the conventional two choices: expose or not expose. Last, we extended and applied prudent and progressive design to entity authentication for pervasive computing environments. A person uses a single device, the Master Key, for entity authentication. The Master Key aggregates one's digital access tokens and automatically discovers and selects proper tokens for authentication. We built mathematical models, designed algorithms, provided theoretical analysis, and designed security protocols. We implemented protocols and built prototype systems. Security protocols were formally verified and analyzed. Threats and attacks were also analyzed, and counter attack measurements were proposed. In addition, much experimentation was conducted to verify our design, to test hypotheses, and to measure performance.
Student selected microcontroller and digital design projects
Authors: M. F. Aburdene
Venue: Proceedings of the 28th Annual Frontiers in Education - Volume 03 (1998)

Summary form only given. The goals of the project assignments were to design, build, test, and document a microcontroller-based system or digital system. The microcontroller course is for the first semester sophomore students in electrical engineering and the digital design course is for first semester junior computer science students. Initially, students submitted a project proposal describing their system and product specifications. This proposal was reviewed by the faculty to make sure that the project could be completed in the allotted time. Once the proposal was approved, the project proposal was posted on the Web and shared with classmates and professors. Working in groups of two to four individuals, students selected the digital/microcontroller systems in consultation with the faculty members. Since the end result of this process would ideally include the actual manufacture of the design, the students were required to hand in a technical report documenting their design, a product specification data sheet for use by the marketing group, and a sales brochure. Two management professors addressed the product versus market approaches to marketing and starting up business from technology and financial perspectives. Students had the opportunity to provide the course professor with progress reports and to present their progress orally to their classmates in lab and class. A first draft was submitted and revisions were suggested. After the revisions were made, the final draft was graded and editorial comments were made.