ppxscal/embedding_network huggingface dataset:
A new OFDM demodulation method to reduce influence of ISI due to longer delay than guard interval
Authors: N. Suzuki, H. Uehara, M. Yokoyama
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 01 (2002)

We propose a new OFDM demodulation method in order to reduce the influence of the intersymbol interference (ISI) and improve the bit error performance in the presence of multipaths whose excess delays are longer than the guard interval (GI). The influence of the ISI is eliminated or reduced by a variable-length windowed reception, and then the ICI component is reduced by a multi-stage intercarrier interference (ICI) canceller. The simulation results show that the proposed method improves the system availability under more various multipath fading environments without changing the system parameters.
Python for Scientific Computing
Authors: Travis E. Oliphant
Venue: Computing in Science and Engineering (2007)

By itself, Python is an excellent "steering" language for scientific codes written in other languages. However, with additional basic tools, Python transforms into a high-level language suited for scientific and engineering code that's often fast enough to be immediately useful but also flexible enough to be sped up with additional extensions.
A Data Mining Approach to Classify Credit Cardholders' Behavior
Authors: Aihua Li, Yong Shi, Meihong Zhu, Jingran Dai
Venue: Proceedings of the Sixth IEEE International Conference on Data Mining - Workshops (2006)

Credit cardholders' behavior analysis is an important issue to be studied. Multi-criteria linear programming (MCLP) classification method has shown its advantage in fast speed and balanced classification accuracy on this problem. However, dimension reduction is necessary before some classification methods implementing, not only for faster classification speed but also for commercial knowledge discovering. In this paper, a data mining approach based on the combination of MCLP and Principal Component Analysis (PCA) is proposed, and the influence of PCA on MCLP classification method is studied. One dataset, which comes from a bank in US, is used to test the performance of this approach, and the advantage of this classification method is shown by experiments.
Direct second-order blind equalization of polyphase channels based on a decorrelation criterion
Authors: C. B. Papadias
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 05 (1999)

We consider the problem of linear polyphase blind equalization (BE), i.e. we are interested in equalizing the output of a single-input-multiple-output (SIMO) channel, without observing its input. A previous result by Liu and Dong (see IEEE Trans. on Circuits and Systems, vol.44, no.5, 1997) showed that if the sub-channel polynomials are co-prime in the z-domain, then the equalizer output whiteness is necessary and sufficient for the equalization of a white input. Based on this observation, we propose a simple decorrelation criterion for second-order based BE. Due to its second-order nature, this criterion is insensitive to the distance of the input from Gaussianity, hence it achieves BE even for Gaussian or non-Gaussian inputs. Moreover, unlike other second-order techniques, our approach bypasses channel estimation and computes directly the equalizer. By doing so, it avoids the problem of ill-conditioning due to channel order mismatch which is crucial to other techniques. Combined to its good convergence properties, these characteristics make the proposed technique an attractive option for robust polyphase BE, as evidenced by both our analysis and computer simulation results.
An Amortized Tit-For-Tat Protocol for Exchanging Bandwidth instead of Content in P2P Networks
Authors: Pawel Garbacki, Dick H. J. Epema, Maarten van Steen
Venue: Proceedings of the First International Conference on Self-Adaptive and Self-Organizing Systems (2007)

Incentives for resource sharing are crucial for the proper operation of P2P networks. The principle of the incen- tive mechanisms in current content sharing P2P networks such as BitTorrent is to have peers exchange content of mu- tual interest. As a consequence, a peer can actively par- ticipate in the system only if it shares content that is of immediate interest to other peers. In this paper we pro- pose to lift this restriction by using bandwidth rather than content as the resource upon which incentives are based. Bandwidth, in contrast to content, is independent of peer interests and so can be exchanged between any two peers. We present the design of a protocol called amortized tit- for-tat (ATFT) based on the bandwidth-exchange concept. This protocol defines mechanisms for bandwidth exchange corresponding to those in BitTorrent for content exchange, in particular for finding bandwidth borrowers that amortize the bandwidth borrowed in the past with their currently idle bandwidth. In addition to the formally proven incentives for bandwidth contributions, ATFT provides natural solu- tions to the problems of peer bootstrapping, seeding incen- tive, peer link asymmetry, and anonymity, which have previ- ously been addressed with much more complex designs. Ex- periments with a real-world dataset confirm that ATFT is efficient in enforcing bandwidth contributions and results in download performance better than provided by incentive mechanisms based on content exchange.
An innovative multidisciplinary elective on optoelectronic materials and devices
Authors: S. M. Lord
Venue: Proceedings of the Frontiers in Education Conference on 1995. Proceedings., 1995 vol 1. - Volume 01 (1995)

An elective course in optoelectronic materials and devices is being developed in the Electrical Engineering Department at Bucknell University. To educate productive engineers who can compete in today's economy, it is essential to introduce them to the important concepts underlying modern multidisciplinary technologies such as optoelectronics. This course was first offered in Spring 1994. The course goals are to provide an introduction to optoelectronic materials and devices and to aid the students' professional development by addressing issues such as the ability to critically evaluate technical papers, conduct effective literature research, and successfully communicate information orally and in writing. The topics explored in the course include band structure, semiconductor alloys, carrier motion, optical processes, photodetectors, LEDs, laser diodes, and optical communication. A basic understanding of device physics is an essential prerequisite for this course to be a success. Variations to the typical lecture format include discussing articles from sources such as Business Week, Scientific American, and IEEE Spectrum, "surfing" on the World Wide Web, field trips, and trade magazines. In addition, students are encouraged to improve upon vital skills for engineers in today's marketplace by researching a topic and presenting their findings orally and in writing. A difficult aspect of preparing a course on a new topic is the lack of a good textbook at the undergraduate level. Experiences with two recently published (1994) textbooks are described. Finally, the laboratory component of the course is considered.
Self-aligned 0-level sealing of MEMS devices by a two layer thin film reflow process
Authors: C. Rusu, H. Jansen, R. Gunn, A. Witvrouw
Venue: Proceedings of the Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS (2003)

Many micro electromechanical systems (MEMS) require a vacuum or controlled atmosphere encapsulation in order to ensure either a good performance or an acceptable lifetime of operation. Two approaches for wafer-scale zero-level packaging exist. The most popular approach is based on wafer bonding. Alternatively, encapsulation can be done by the fabrication and sealing of perforated surface micromachined membranes. In this paper, a sealing method is proposed for zero-level packaging using a thin film reflow technique. This sealing method can be done at arbitrary ambient and pressure. Also, it is self-aligned and it can be used for sealing openings directly above the MEMS device. It thus allows for a smaller die area for the sealing ring reducing in this way the device dimensions and costs. The sealing method has been demonstrated with reflowed aluminium, germanium, and boron phosphorous silica glass. This allows for conducting as well as non-conducting sealing layers and for a variety of allowable thermal budgets. The proposed technique is therefore very versatile.
Effective automatic parallelization of stencil computations
Authors: Sriram Krishnamoorthy, Muthu Baskaran, Uday Bondhugula, J. Ramanujam, Atanas Rountev, P Sadayappan
Venue: ACM SIGPLAN Notices (2007)

Performance optimization of stencil computations has been widely studied in the literature, since they occur in many computationally intensive scientific and engineering applications. Compiler frameworks have also been developed that can transform sequential stencil codes for optimization of data locality and parallelism. However, loop skewing is typically required in order to tile stencil codes along the time dimension, resulting in load imbalance in pipelined parallel execution of the tiles. In this paper, we develop an approach for automatic parallelization of stencil codes, that explicitly addresses the issue of load-balanced execution of tiles. Experimental results are provided that demonstrate the effectiveness of the approach.
Distributed Server Selection and Admission Control in Replicated Web Systems
Authors: N. Bartolini, G. Bongiovanni, Simone Silvestri
Venue: Proceedings of the Sixth International Symposium on Parallel and Distributed Computing (2007)

This paper addresses the problems of admission control and server selection in a system consisting of several geographically replicated web servers and several access points. We propose a fully distributed solution in which every access point continuously monitors the availability of all server side resources, using a mixture of active and passive measurements. Based on those measures, each access point autonomously applies its decisions to the requests it receives. Admission control is performed prioritizing requests belonging to already admitted sessions, in order to maximize the chance of successfully terminating ongoing sessions. Furthermore, session information is taken into account when performing a probabilistic request redirection and server choice, in order to improve load balancing and mitigate flash crowd effects. Extensive simulations, performed in compliance with industry standards, show that our method exhibits a stable behavior during overloads and improves service quality in terms of both reduced response time and higher successful session termination.
On the use of support vector machines for phonetic classification
Authors: P. Clarkson
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 02 (1999)

Support vector machines (SVMs) represent a new approach to pattern classification which has attracted a great deal of interest in the machine learning community. Their appeal lies in their strong connection to the underlying statistical learning theory, in particular the theory of structural risk minimization. SVMs have been shown to be particularly successful in fields such as image identification and face recognition; in many problems SVM classifiers have been shown to perform much better than other nonlinear classifiers such as artificial neural networks and k-nearest neighbors. This paper explores the issues involved in applying SVMs to phonetic classification as a first step to speech recognition. We present results on several standard vowel and phonetic classification tasks and show better performance than Gaussian mixture classifiers. We also present an analysis of the difficulties we foresee in applying SVMs to continuous speech recognition problems.
Improving performance and energy consumption in region-based caching architectures
Authors: Trevor N. Mudge, Gary S. Tyson
Venue:  (2006)

Embedded systems must simultaneously deliver high performance and low energy consumption. Meeting these goals requires customized designs that fit the requirements of the targeted applications. This philosophy of tailoring the implementation to the domain applies to all subsystems in the embedded architecture. For the memory system, which is a key performance bottleneck and a significant source of energy consumption, generic caching strategies are insufficient. The system requires specialized cache structures that match the manner in which programmers use data. Since different data subsets exhibit varying degrees of locality, a partitioned cache offers the best opportunity to optimize performance and energy consumption for all memory accesses. In this dissertation, I explore several different methods that utilize partitioning for an energy-efficient, high performance data cache. Region-based caching, which replaces a unified data cache with multiple caches optimized for stack, global, and heap references, serves as the starting point for this research. I begin by addressing energy consumption in the level one data cache. Drowsy region-based caches combine static and dynamic energy reduction techniques to simultaneously lower both sources of energy consumption. This combination performs better than the sum of its parts because the separate region caches allow us to use different degrees of drowsy caching. I then show how additional cache partitioning can further reduce energy consumption, presenting a scheme to identify highly local data in the heap region and route their accesses to a smaller cache. I also study methods for improving memory system performance. The effectiveness of data prefetching can be increased by partitioning the cache in a manner that isolates data that prefetch well. Finally, I discuss how to reallocate data within region-based caches to eliminate unnecessary cache misses.
Hybrid image-/model-based gaze-contingent rendering
Authors: Hunter Murphy, Andrew T. Duchowski
Venue: Proceedings of the 4th symposium on Applied perception in graphics and visualization (2007)

A nonisotropic hybrid image-/model-based gaze-contingent rendering technique utilizing ray casting on a GPU is discussed. Empirical evidence derived from human subject experiments indicates an inverse relationship between a peripherally degraded scene's high-resolution inset size and mean search time, a trend consistent with existing image- and model- based techniques. In addition, the data suggest that maintaining a target's silhouette edges decreases search times when compared to targets with degraded edges. Benefits of the hybrid technique include simplicity of design and parallelizability, both conducive to GPU implementation.
An Application Platform Enabling High Performance Grid Processing of Microarray Experiments
Authors: Ilias Maglogiannis, Aristotelis Chatzioannou, John Soldatos, Vasileios Mylonakis, Yiannis Kanaris
Venue: Proceedings of the Twentieth IEEE International Symposium on Computer-Based Medical Systems (2007)

Reliable microarray experiments are extremely computationally demanding given the need to perform complex calculations over a multitude of data. Grid computing can provide a remedy to this problem through accelerating the computations associated with microarray normalization, while at the same time providing access to vast amounts of federated storage resources. The present paper presents the application architecture for the HECTOR project, which aims at deploying software for microarray experiments over the Hellenic Grid infrastructure. Emphasis is given on a set of structuring principles that instruct how the various microarray software components are distributed on the Grid. These structuring principles are illustrated in the form of a coherent architecture enabling the operation of microarray applications over the Grid. The description of this architecture is oriented to Grid developers and users, since it focuses on the customization and use of the microarray applications over the Grid, rather than on issues relating to the Grid infrastructure and middleware.
A Robust and Efficient Mechanism to Distribute Certificate Revocation Information Using the Grid Monitoring Architecture
Authors: Daniel Kouril, Ludek Matyska, Michal Prochazka
Venue: Proceedings of the 21st International Conference on Advanced Information Networking and Applications Workshops - Volume 01 (2007)

Checking revocation information is necessary to prevent from using digital certificates whose contents become in- valid. In current system either periodical retrieval of Cer- tificate Revocation Lists (CRLs) or the Online Certificate Status Protocol (OCSP) are the most common mechanisms to access revocation information issued by the certifica- tion authorities. As both these approaches pose problems we propose a new method based on a Push model, which is based on the Grid Monitoring Architecture. Using this approach we guarantee the revocation information is dis- tributed in a robust and timely manner. We also describe a pilot implementation of the service based on the proposed design.
Computational Science for Natural Resource Management
Authors: Michael M. Fuller, Dali Wang, Louis J. Gross, Michael W. Berry
Venue: Computing in Science and Engineering (2007)

Recent advances in miniaturization, computing power, remote sensing, and modeling are revolutionizing the science of natural resource management. But these advances also bring many challenges. This article highlights some key problems in resource management that represent opportunities for computer scientists and engineers in search of challenging practical problems.
On the performance of the Viterbi decoder with trained and semi-blind channel estimators
Authors: A. Gorokhov
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 05 (1999)

Maximum-likelihood sequence estimation is often used to recover digital signals transmitted over finite memory convolutive channels when an estimate of the channel is available. We study the impact of channel estimation errors on the quality of sequence detection. The general case of single input multiple output (SIMO) channels is considered. An asymptotic upper bound for the symbol error rate is presented which allows to treat channel estimation errors as equivalent losses in signal-to-noise ratio (SNR). This relationship is studied and numerically validated for the standard least squares channel estimate and for the semi-blind estimator which makes use of the empirical subspace of the observed data.
Bus-Based Tree Structures for Efficient Parallel Computation
Authors: O. M. Dighe, R. Vaidyanathan, S. Q. Zheng
Venue: Proceedings of the 1993 International Conference on Parallel Processing - Volume 01 (1993)

We propose a class of new multiprocessor structures called bus based trees (BBTs) that are based on multiple buses. We show that a BBT can simulate a tree machine optimally. We also discuss optimal VLSI layouts for the BBT and show that the BBT can be used as a building block to construct new powerful parallel computing structures.
Exploiting nonstationarity for performance prediction
Authors: Christopher Stewart, Terence Kelly, Alex Zhang
Venue: ACM SIGOPS Operating Systems Review (2007)

Real production applications ranging from enterprise applications to large e-commerce sites share a crucial but seldom-noted characteristic: The relative frequencies of transaction types in their workloads are nonstationary, i.e., the transaction mix changes over time. Accurately predicting application-level performance in business-critical production applications is an increasingly important problem. However, transaction mix nonstationarity casts doubt on the practical usefulness of prediction methods that ignore this phenomenon. This paper demonstrates that transaction mix nonstationarity enables a new approach to predicting application-level performance as a function of transaction mix. We exploit nonstationarity to circumvent the need for invasive instrumentation and controlled benchmarking during model calibration; our approach relies solely on lightweight passive measurements that are routinely collected in today's production environments. We evaluate predictive accuracy on two real business-critical production applications. The accuracy of our response time predictions ranges from 10% to 16% on these applications, and our models generalize well to workloads very different from those used for calibration. We apply our technique to the challenging problem of predicting the impact of application consolidation on transaction response times. We calibrate models of two testbed applications running on dedicated machines, then use the models to predict their performance when they run together on a shared machine and serve very different workloads. Our predictions are accurate to within 4% to 14%. Existing approaches to consolidation decision support predict post-consolidation resource utilizations. Our method allows application-level performance to guide consolidation decisions.
Mechanizing common knowledge logic using COQ
Authors: Pierre Lescanne
Venue: Annals of Mathematics and Artificial Intelligence (2006)

This paper presents a formalization in Coq of Common Knowledge Logic and checks its adequacy on case studies. Those studies allow exploring experimentally the proof-theoretic side of Common Knowledge Logic. This work is original in that nobody has considered Higher Order Common Knowledge Logic from the point of view of proofs performed on a proof assistant. As a matter of facts, it is experimental by nature as it tries to draw conclusions from experiments.
Visualizations in Preparing for Programming Exercise Sessions
Authors: Tuukka Ahoniemi, Essi Lahtinen
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2007)

Visualizations are widely researched and used in teaching but the results of their benefits in learning are vague. We introduce an experiment of using visualizations in learning introductory programming. The aim was to support students in their preparation for the exercise sessions by using visualizations. The students' preparation consists of two phases that both are supported: reviewing the subject and a homework assignment. Thus this is also a novel approach to using programming visualizations and integrating them to the course content. The experiment shows positive results especially among the students with no prior programming experience and the students who consider the programming course challenging. We conclude that integrating the use of visualizations to students' preparation for exercise sessions leads to better learning, more meaningful studying, and ultimately to better preparation. Therefore we also suggest this as a possible way for integrating visualizations to the course.