ppxscal/embedding_network huggingface dataset:
An algorithm for approximate counting using limited memory resources
Authors: Andrej Cvetkovski
Venue: ACM SIGMETRICS Performance Evaluation Review (2007)

This paper describes a randomized algorithm for approximate counting that preserves the same modest memory requirements of log(log n) bits per counter as the approximate counting algorithm introduced in the seminal paper of R. Morris (1978), and in addition, is characterized by (i) lower expected number of memory accesses and (ii) lower standard error on more than 99 percent of its counting range. An exact analysis of the relevant statistical properties of the algorithm is carried out. Performance evaluation via simulations is also provided to validate the presented theory. Given its properties, the presented algorithm is suitable as a basic building block of data streaming applications having a large number of simultaneous counters and/or operating at very high speeds. As such, it is applicable to a wide range of measurement and monitoring operations, including performance monitoring of communication hardware, measurements for optimization in large database systems, and gathering statistics for data compression.
Audio signal noise reduction using multi-resolution sinusoidal modeling
Authors: D. V. Anderson
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 02 (1999)

The sinusoidal transform (ST) provides a sparse representation for speech signals by utilizing several psychoacoustic phenomena. It is well suited to applications in signal enhancement because the signal is represented in a parametric manner that is easy to manipulate. The multi-resolution sinusoidal transform (MRST) has the additional advantage that it is both particularly well suited to typical speech signals and well matched to the human auditory system. The currently reported work discusses the removal of noise from a noisy signal by applying an adaptive Wiener filter to the MRST parameters and then conditioning the parameters to eliminate "musical noise". In informal tests MRST based noise reduction was found to reduce background noise significantly better than traditional Wiener filtering and to virtually eliminate the "musical noise" often associated with Wiener filtering.
Interactive presentation: PowerQuest: trace driven data mining for power optimization
Authors: Pietro Babighian, Gila Kamhi, Moshe Vardi
Venue: Proceedings of the conference on Design, automation and test in Europe (2007)

We introduce a general framework, called PowerQuest, with the primary goal of extracting "interesting" dynamic invariants from a given simulation-trace database, and applying it to the power-reduction problem through detection of gating conditions. PowerQuest adopts machine-learning techniques for data mining. The advantages of PowerQuest in comparison with other state-of-the-art Dynamic Power Management (DPM) techniques are: 1) Quality of ODC conditions for gating 2) Minimization of extra logic added for gating. We demonstrate the validity of our approach in reducing power through experimental results using ITC99 benchmarks and real-life microprocessor test cases. We present up to 22.7 % power reduction in comparison with other DPM techniques.
TCP offload is a dumb idea whose time has come
Authors: Jeffrey C. Mogul
Venue: Proceedings of the 9th conference on Hot Topics in Operating Systems - Volume 9 (2003)

Network interface implementors have repeatedly attempted to offload TCP processing from the host CPU. These efforts met with little success, because they were based on faulty premises. TCP offload per se is neither of much overall benefit nor free from significant costs and risks. But TCP offload in the service of very specific goals might actually be useful. In the context of the replacement of storage-specific interconnect via commoditized network hardware, TCP offload (and more generally, offloading the transport protocol) appropriately solves an important problem.
Visualizing berkeley socket calls in students' programs
Authors: Christian Brown, Chris McDonald
Venue: ACM SIGCSE Bulletin (2007)

The Berkeley Sockets API is a library of functions, macros, and data structures enabling a program to initiate and manage network communication between two or more processes on the same machine, or across a network of machines. The API is the main mechanism by which programs communicate with the operating system's TCP/IP stack and thereby with almost all Internet services and programs. Socket programming opens a new realm of development for Computer Science students as they are able to create programs that can communicate via the Internet. However, while learning, students frequently misuse the sockets API or have difficulty understanding where run-time and logic errors in their code occur. Students learning about sockets are typically presented with a series of static diagrams in textbooks that increase in complexity with each progression. These diagrams may not allow the reader to easily comprehend the transition between each step, nor understand which functions in the API perform the events. Space constraints in textbooks often limit a sequence of diagrams to two or three, whereas over 10 calls to the sockets API are often necessary to initiate and undertake communication. Surprisingly, there are no effective tools or general techniques for debugging students' socket programs. In this paper we present a software solution to visualize the execution of students' programmed interactions with the Berkeley Sockets API. The tool accepts the source code of two or more networking programs and compiles them in such a way that, at run-time, their calls to the socket API and related functions are displayed, together with an annotation of activity and error conditions. The program is not simply a static simulator - it provides a means to visualize the network events in actual student developed program.
Empirical analysis on the correlation between GCC compiler warnings and revision numbers of source files in five industrial software projects
Authors: Raimund Moser, Barbara Russo, Giancarlo Succi
Venue: Empirical Software Engineering (2007)

This article discusses whether using warnings generated by the GNU C++ compiler can be used effectively to identify source code files that are likely to be error prone. We analyze five industrial projects written in C++ and belonging to the telecommunication domain. We find a significant positive correlation between the number of compiler warnings and the number of source files changes. We use such correlation to conclude that compiler warnings may be used as an indicator for the presence of software defects in source code. The result of this research is useful for finding defect-prone modules in newer projects, which lack change history.
Phase adjustment in waveform interpolation
Authors: Hong-Goo Kang
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 01 (1999)

This paper describes a method of improving the quality of the waveform interpolation (WI) speech coder by adjustment of the phase information. In WI, a slowly-evolving waveform (SEW) and a rapidly-evolving waveform (REW) represent the periodic and the non-periodic part of the signal. The phase of the synthesized signal is determined by the SEW and REW, and thus the correct quantization of these parameters is important to producing natural speech quality. A method is described, whereby the phase of the synthesized signal is adjusted by modifying the quantized REW spectrum as a function of the fundamental frequency. This essentially attempts to correct the discrepancies in phase that arise due to variation in pitch and also accounts for the difference in noise sensitivity between female and male speech. The overall effect would be the same if multiple codebooks (depending on pitch) were used to code the REW spectrum. Experimental results confirm that the new method results in significantly improved performance.
A Web-Based Authoring System Supporting Metadata
Authors: Eric Jui-Lin Lu, Gwoboa Horng, Chia-Ssu Yu, Ling-ying Chou
Venue: Proceedings of the Twentieth IEEE International Symposium on Computer-Based Medical Systems (2007)

Today, networks can be seen as a large-scale knowledge base which contains a huge amount of resources. To be able to use them effectively, metadata should be associated with each sharable resource. As a result, authoring systems supporting metadata have been widely studied. In this paper, we attempt to develop an authoring system supporting metadata. From our previous research, it is found that "RELATION" is an important metadata, and a relation ontology was proposed. However, existing authoring systems do not support the relation ontology. Therefore, we continued our previous work and developed a web-based authoring system supporting the relation ontology. With the authoring system, we believe the reusability of network resources can be significantly increased.
On a Modeling Framework for the Analysis of Interdependencies in Electric Power Systems
Authors: Silvano Chiaradonna, Paolo Lollini, Felicita Di Giandomenico
Venue: Proceedings of the 37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (2007)

Nowadays, economy, security and quality of life heavily depend on the resiliency of a number of critical infrastructures, including the Electric Power System (EPS), through which vital services are provided. In existing EPS two cooperating infrastructures are involved: the Electric Infrastructure (EI) for the electricity generation and transportation to final users, and its Information-Technology based Control System (ITCS) devoted to controlling and regulating the EI physical parameters and triggering reconfigurations in emergency situations. This paper proposes a modeling framework to capture EI and ITCS aspects, focusing on their interdependencies that contributed to the occurrence of several cascading failures in the past 40 years. A quite detailed analysis of the EI and ITCS structure and behavior is performed; in particular, the ITCS and EI behaviors are described by discrete and hybrid-state processes, respectively. To substantiate the approach, the implementation of a few basic modeling mechanisms inside an existing multiformalism/ multi-solution tool is also discussed.
Variational Method for Image Denoising by Distributed Genetic Algorithms on GRID Environment
Authors: F. Cannavo, G. Nunnari, D. Giordano, C. Spampinato
Venue: Proceedings of the 15th IEEE International Workshops on Enabling Technologies: Infrastructure for Collaborative Enterprises (2006)

The aim of this paper is to present a novel distributed genetic algorithm architecture implemented on grid computing by using the G-Lite middleware developed in the EGEE project. Genetic algorithms are known for their capability to solve a wide range of optimization problems and one of the most relevant feature of GAs is their structural parallelism, that fits well the intrinsically distributed GRID architecture. The proposed architecture is based on different specialized autonomous entities able to interact in order to carry out a global optimization task. The interaction is based on exchange of knowledge on the problem and solutions. In this way the main problem can be solved by using many cooperative small entities that can be classified into different specialized families that cover only one aspect of the global problem. The topology is based on archipelagos of islands that interact by chromosomes migrating with an user-definable strategy. Grid has been mainly used in the high performance computing area. The properties of the proposed GAs architecture and its related computing properties have great potential in solving big instances of optimization problems. Furthermore this implementation (distributed genetic algorithms with grid computing) is suitable to solve time consuming problems reducing by executing different instances on many virtual organizations (VOs) according to the Grid philosophy. The proposed parallel algorithm has been tested on denoising problems applied to image processing which are known to be time consuming. The paper reports some results about the time performance compared to traditional denoising filter algorithms.
strlcpy and strlcat: consistent, safe, string copy and concatenation
Authors: Todd C. Miller, Theo de Raadt
Venue: Proceedings of the annual conference on USENIX Annual Technical Conference (1999)

As the prevalence of buffer overflow attacks has increased, more and more programmers are using size or length-bounded string functions such as strncpy() and strncat(). While this is certainly an encouraging trend, the standard C string functions generally used were not really designed for the task. This paper describes an alternate, intuitive, and consistent API designed with safe string copies in mind. There are several problems encountered when strncpy() and strncat() are used as safe versions of strcpy() and strcat(). Both functions deal with NUL-termination and the length parameter in different and non-intuitive ways that confuse even experienced programmers. They also provide no easy way to detect when truncation occurs. Finally, strncpy() zero-fills the remainder of the destination string, incurring a performance penalty. Of all these issues, the confusion caused by the length parameters and the related issue of NUL-termination are most important. When we audited the OpenBSD source tree for potential security holes we found rampant misuse of strncpy() and strncat(). While not all of these resulted in exploitable security holes, they made it clear that the rules for using strncpy() and strncat() in safe string operations are widely misunderstood. The proposed replacement functions, strlcpy() and strlcat(), address these problems by presenting an API designed for safe string copies (see Figure 1 for function prototypes). Both functions guarantee NUL-termination, take as a length parameter the size of the string in bytes, and provide an easy way to detect truncation. Neither function zero-fills unused bytes in the destination.
Performance Evaluations of the FTOG Framework for Effective Object Management and Load Distribution
Authors: Myung Seok Kang, Jong Hyuk Park, Hag Bae Kim
Venue: Proceedings of the 15th Euromicro International Conference on Parallel, Distributed and Network-Based Processing (2007)

This paper presents a Fault-Tolerant Object Group (FTOG) framework that provides both group management service and load scheduling service for consistency maintenance as well as state transparency. The group management service manages the overall FTOG framework while providing a couple of schemes to overcome unexpected faults. The load scheduling service effectively distributes the client requests to improve the Quality of Service by considering the load of service objects. We develop an Intelligent Home Network Simulator (IHNS) as a simulation program for using the FTOG framework on distributed environments. Through certain simulations, we validate that the FTOG framework supports both of reliability and stability of the distributed home-networking systems
Enclaves: enabling secure collaboration over the internet
Authors: Li Gong
Venue: Proceedings of the 6th conference on USENIX Security Symposium, Focusing on Applications of Cryptography - Volume 6 (1996)

The rapid expansion of the Internet means that users increasingly want to interact with each other. Due to the openness and unsecure nature of the net, users often have to rely on firewalls to protect their connections. Firewalls, however, make real-time interaction and collaboration more difficult. Firewalls are also complicated to configure and expensive to install and maintain, and are inaccessible to small home offices and mobile users. The Enclaves approach is to transform user machines into "enclaves," which are protected from outside interference and attacks. Using Enclaves, a group of collaborators can dynamically form a secure virtual subnet within which to conduct their joint business. This paper describes the design and implementation of the Enclaves toolkit, and some applications we have built using the toolkit.
Incorporating a Variable-Expertise-Level System in IT Course Modules
Authors: Nicholas Harkiolakis
Venue: Computer (2007)

Mixing IT expertise levels helps students model real-world learning experiences.
An Overlap Removal Algorithm for Macrocell Placement in VLSI Layouts
Authors: M. Thenappan, Arasu T. Senthil, K. M. Sreekanth, Ramesh S. Guzar
Venue: Proceedings of the International Conference on Computing: Theory and Applications (2007)

An efficient overlap removal algorithm in the context of macrocell placement is presented in this paper. The algorithm works on a novel augmented constraint graph and removes overlap in the presence of fixed location, spacing and boundary constraints imposed on macro cells. We propose a modifed Parallel Plane Shadowing Sweep algorithm for creation of constraint graph and an augmentation scheme to handle constraints effectively. The spatial relations that exist among the macro cells in an overlapping placement is retained in the overlap free placement. A peripheral placement of macro cells is made feasible by utilizing the information in the constraint graph to compact the macro cells towards the periphery in conjunction with the legalization of the macro cells. Experimental results obtained with and without compaction on randomly generated testcases based on GSRC floorplanning benchmarks is presented. The run-time of the algorithm has been shown to scale linearly with increasing number of blocks.
The matrix-restricted total least-squares problem
Authors: Amir Beck
Venue: Signal Processing (2007)

We present and study the matrix-restricted total least squares (MRTLS) devised to solve linear systems of the form Ax~b where A and b are both subjected to noise and A has errors of the form DEC. D and C are known matrices and E is unknown. We show that the MRTLS problem amounts to solving a problem of minimizing a sum of fractional quadratic terms and a quadratic function and compare it to the related restricted TLS problem of Van Huffel and Zha [The restricted total least squares problem: formulation, algorithm, and properties, SIAM J. Matrix Anal. Appl. 12(2) (1991) 292-309.]. Finally, we present an algorithm for solving the MRTLS, which is based on a reduction to a single-variable minimization problem. This reduction is shown to have the ability of eliminating local optima points.
Computational consequences of experimentally derived spike-time and weight dependent plasticity rules
Authors: Dominic Standage, Sajiya Jalil, Thomas Trappenberg
Venue: Biological Cybernetics (2007)

We present two weight- and spike-time dependent synaptic plasticity rules consistent with the physiological data of Bi and Poo (J Neurosci 18:10464&#x2013;10472, 1998). One rule assumes synaptic saturation, while the other is scale free. We extend previous analyses of the asymptotic consequences of weight-dependent STDP to the case of strongly correlated pre- and post-synaptic spiking, more closely resembling associative learning. We further provide a general formula for the contribution of any number of spikes to synaptic drift. Asymptotic weights are shown to principally depend on the correlation and rate of pre- and post-synaptic activity, decreasing with increasing rate under correlated activity, and increasing with rate under uncorrelated activity. Spike train statistics reveal a quantitative effect only in the pre-asymptotic regime, and we provide a new interpretation of the relation between BCM and STDP data.
PTS Peak Power Reduction of OFDM Signals with Low Complexity IFFTs
Authors: A. Ghassemi, T. A. Gulliver
Venue: Proceedings of the Fifth Annual Conference on Communication Networks and Services Research (2007)

Partial transmit sequence (PTS) is a distortionless technique used to reduce the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) signal. However, it has a relatively high computational complexity due to the computation of multiple inverse fast Fourier transforms (IFFTs). We reduce this complexity by using a radix FFT that computes multiple IFFTs with low computational complexity. Signals at the middle stages of an N-point radix-r FFT using decimation in frequency (DIF) are employed for PTS subblocking. Performance results are presented which show that PAPR reduction similar to other techniques such as ordinary PTS (O-PTS) is achieved.
Simple MMSE equalizers for CDMA downlink to restore chip sequence: comparison to zero-forcing and RAKE
Authors: T. P. Krauss
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 05 (2000)

This work focuses on the forward link in a CDMA based multiuser communication system experiencing frequency dependent multipath fading. The mobile handset is assumed to have two antennas, either spatially separated or having diverse polarizations. Previous work on linear equalizers to restore orthogonality of the Walsh-Hadamard channel codes in this scenario led to a comparison of zero-forcing (ZF) equalizers and the RAKE receiver. A chip-rate MMSE equalizer is derived that minimizes the MSE between the synchronous "sum signal" of all the users from a given base station and the equalized chip sequence; this equalizer is followed by correlation with the desired user's spreading code times the base-station's long code. In this MMSE derivation, the sum of chip sequences of all the users is modeled as an i.i.d. random sequence. This leads to a "simple" MMSE equalizer that does not depend on the Walsh-Hadamard spreading codes, or the long code, currently employed at the base station. For further improvement, the "best" equalizer delay is chosen to minimize the MSE. Theoretically, the MMSE equalizer approaches the RAKE receiver at low SNR and the ZF equalizer at high SNR. Simulation results show that the ZF equalizer's average performance is dominated by a very small percentage of "bad channels" with close to common zeroes, while the MMSE equalizer is resistant to this pathological noise gain problem. The end result is that the MMSE's average BER performance is dramatically better than that of both ZF and RAKE (even though only moderately better than ZF for most well behaved channels).
PLAYAS: critical reflection in an immersive space
Authors: Jack E. Stenner
Venue: Proceedings of the 6th ACM SIGCHI conference on Creativity cognition (2007)

This paper proposes a demonstration of the hybrid video game and installation environment, Playas: Homeland Mirage. Exhibited at ISEA/ZeroOne 2006 [1]. The collaboratively developed project serves as a model of artist-driven research. This demonstration will discuss the findings gathered from a naturalistic inquiry into the effect of mediation on critical reflection.
Faster algorithms for sorting by transpositions and sorting by block interchanges
Authors: Jianxing Feng, Daming Zhu
Venue: ACM Transactions on Algorithms (TALG) (2007)

In this article, we present a new data structure, called the permutation tree, to improve the running time of sorting permutation by transpositions and sorting permutation by block interchanges. The existing 1.5-approximation algorithm for sorting permutation by transpositions has time complexity O(n3/2 &sqrt;logn). By means of the permutation tree, we can improve this algorithm to achieve time complexity O(nlogn). We can also improve the algorithm for sorting permutation by block interchanges to take its time complexity from O(n2) down to O(nlogn).