ppxscal/embedding_network huggingface dataset:
Adaptive Frequency Synchronization for Collaborative Communication Systems
Authors: Peter A. Parker, Daniel W. Bliss, Patrick Mitran, Vahid Tarokh
Venue: Proceedings of the 27th International Conference on Distributed Computing Systems Workshops (2007)

Cooperative diversity systems are wireless communication systems designed to exploit cooperation among users to mitigate the effects of multipath fading. In fairly general conditions, it has been shown that these systems can achieve the diversity order of an equivalent MISO channel and, if the node geometry permits, virtually the same outage probability is achieved as that of the equivalent MISO channel for a wide range of applicable SNR. However, much of the prior analysis has been performed under the assumption of perfect timing and frequency offset synchronization. In this paper, we derive the estimation bounds and associated maximum likelihood estimators for frequency offset estimation in a cooperative communication system. The cooperative nature of the system is utilized to reduce the estimation error with respect to standard (non-cooperative) frequency estimation algorithms. For a worst case frequency offset distribution among the nodes, we show that this estimator is optimal in the sense of estimation error variance.
Low power implementation of FFT/IFFT processor for IEEE 802.11a wireless LAN transceiver
Authors: D. L. G. Yeo, Zhongjun Wang, Bin Zhao, Yajuan He
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 01 (2002)

In an orthogonal frequency division multiplexing (OFDM) system, the fast Fourier transform (FFT) is one of the major processing blocks. The inverse FFT (IFFT) is used to modulate a serially transmitted signal into parallel orthogonal signals while demodulation is achieved by FFT at the receiver. With the limited battery life, energy efficiency is becoming crucial in the design of next generation wireless systems. Typically, power conservation is used in the hardware design of such systems. This paper presents an efficient scheme using reduced precision and wordlength optimization to reduce power and increase performance of FFT in the transmitter for IEEE 802.11a WLAN applications. With reduced input bits during transmission, simulation results show that the power consumption of the butterfly functional unit can be reduced considerably.
A novel approach to Bilevel nonlinear programming
Authors: H. Tuy, A. Migdalas, N. T. Hoai-Phuong
Venue: Journal of Global Optimization (2007)

Recently developed methods of monotonic optimization have been applied successfully for studying a wide class of nonconvex optimization problems, that includes, among others, generalized polynomial programming, generalized multiplicative and fractional programming, discrete programming, optimization over the efficient set, complementarity problems. In the present paper the monotonic approach is extended to the General Bilevel Programming GBP Problem. It is shown that (GBP) can be transformed into a monotonic optimization problem which can then be solved by "polyblock" approximation or, more efficiently, by a branch-reduce-and-bound method using monotonicity cuts. The method is particularly suitable for Bilevel Convex Programming and Bilevel Linear Programming.
A Unilaterally Constrained Quadratic Minimization with Adaptive Finite Elements
Authors: Kunibert G. Siebert, Andreas Veeser
Venue: SIAM Journal on Optimization (2007)

We consider obstacle problems where a quadratic functional associated with the Laplacian is minimized in the set of functions above a possibly discontinuous and thin but piecewise affine obstacle. In order to approximate minimum point and value, we propose an adaptive algorithm that relies on minima with respect to admissible linear finite element functions and on an a posteriori estimator for the error in the minimum value. It is proven that the generated sequence of approximate minima converges to the exact one. Furthermore, our numerical results in two and three dimensions indicate that the convergence rate with respect to the number of degrees of freedom is optimal in that it coincides with the one of nonlinear or adaptive approximation.
An Introduction to Effectively Evaluating Software Architectures
Authors: Len Bass, Robert L. Nord
Venue: Proceedings of the Sixth Working IEEE/IFIP Conference on Software Architecture (2007)

Software architecture has become a widely-accepted conceptual basis for the development of non-trivial software in all application areas and by organizations of all sizes. Effectively evaluating architecture is as important as crafting it in order to have assurance that it successfully addresses the target system qualities, which in turn, help fulfill the business goals of the system.
Overcoming the Digital Divide through Electronic Commerce: Harnessing opportunities in IT for Development
Authors: Sajda Qureshi, Alanah Davis
Venue: Proceedings of the 40th Annual Hawaii International Conference on System Sciences (2007)

The disparities in access to and use of information and communication technologies (ICTs) comprise a divide between those who can and cannot reap the benefits of the information superhighway. Electronic commerce appears to enable this divide to be overcome. This paper provides insight into the ways in which development is brought about through ICTs. Following an analysis of the key factors effecting development through e-commerce, the contribution of this paper is in a framework that describes the relationship between the tools and benefits of e-commerce and its effect on development.
Targeting CCM-, CEA-, and CSM-Based Computing to Specific Architectures Based upon HPCMP Systems Assessment
Authors: Paul M. Bennett, Sam B. Cable, Mahin Mahmoodi, Thomas C. Oppe
Venue: Proceedings of the HPCMP Users Group Conference (2006)

Each year the Department of Defense High Performance Computing Modernization Program (HPCMP) acquires new supercomputing hardware through a rigorous acquisition process, denoted "TI for technology insertion, based primarily on application benchmarking. The corresponding suite of applications spans many disciplines and is carefully constructed to ensure that the HPCMP workload is accurately reflected. For the most recent acquisition cycle (TI-06), GAMESS, LAMMPS, OOCORE, and CTH7 were used to represent the computational chemistry and materials (CCM), computational electromagnetics and acoustics (CEA), and computational structural mechanics (CSM) computational technology areas (CTAs) in the workload, respectively. This paper will compare the performance of these four codes representing the CCM, CEA, and CSM components, respectively, of the TI-06 benchmarking suite on HPCMP systems to determine which system is best suited for each CTA.
Enabling compiler flow for embedded VLIW DSP processors with distributed register files
Authors: Chung-Kai Chen, Ling-Hua Tseng, Shih-Chang Chen, Young-Jia Lin, Yi-Ping You, Chia-Han Lu, Jenq-Kuen Lee
Venue: ACM SIGPLAN Notices (2007)

High-performance and low-power VLIW DSP processors are increasingly deployed on embedded devices to process video and multimedia applications. For reducing power and cost in designs of VLIW DSP processors, distributed register files and multi-bank register architectures are being adopted to eliminate the amount of read/write ports in register files. This presents new challenges for devising compiler optimization schemes for such architectures. In this paper, we address the compiler optimization issues for PAC architecture, which is a 5-way issue DSP processor with distributed register files. We present an integrated flow to address several phases of compiler optimizations in interacting with distributed register files and multi-bank register files in the layer of instruction scheduling, software pipelining, and data flow optimizations. Our experiments on a novel 32-bit embedded VLIW DSP (known as the PAC DSP core) exhibit the state of the art performance for embedded VLIW DSP processors with distributed register files by incorporating our proposed schemes in compilers.
Name dialing-how useful is it?
Authors: K. Laurila
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 06 (2000)

Progress in automatic speech recognition technology has resulted in an increasing amount of deployed applications. Typically, the measure of success has been the amount of deployed or sold units and it has been much more difficult to evaluate the real user benefit from the technology. Actually, the usability, or usefulness, has largely remained an open issue. In this paper we focus on name dialing and discuss its usefulness from different angles, with a strong emphasis on mass market use and inexperienced users. As a concept, name dialing brings us back from where telephony started: an operator assisted way of making calls without a need to remember numbers. In essence, name dialing offers a solution to a minor inconvenience-using the directory. Even the arguably biggest advantage of name dialing, simplified car usage, is still less significant than the various concerns of users. Until time and further technical improvements alleviate the main concerns, usage of name dialing will remain as an occasional, rather than a primary, way of making calls.
Through Modeling to Synthesis of Security Automata
Authors: Fabio Martinell, Ilaria Matteucci
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2007)

We define a set of process algebra operators, that we call controller operators, able to mimic the behavior of security automata introduced by Schneider in [Schneider, F. B., Enforceable security policies, ACM Transactions on Information and System Security 3 (2000), pp. 30-50] and by Ligatti and al. in [Bauer, L., J. Ligatti and D. Walker, More enforceable security policies, in: I. Cervesato, editor, Foundations of Computer Security: proceedings of the FLoC'02 workshop on Foundations of Computer Security (2002), pp. 95-104]. Security automata are mechanisms for enforcing security policies that specify acceptable executions of programs. Here we give the semantics of four controllers that act by monitoring possible un-trusted component of a system in order to enforce certain security policies. Moreover, exploiting satisfiability results for temporal logic, we show how to automatically build these controllers for a given security policy.
Distributed directory service in the farsite file system
Authors: John R. Douceur, Jon Howell
Venue: Proceedings of the 7th USENIX Symposium on Operating Systems Design and Implementation - Volume 7 (2006)

We present the design, implementation, and evaluation of a fully distributed directory service for Farsite, a logically centralized file system that is physically implemented on a loosely coupled network of desktop computers. Prior to this work, the Farsite system included distributed mechanisms for file content but centralized mechanisms for file metadata. Our distributed directory service introduces tree-structured file identifiers that support dynamically partitioning metadata at arbitrary granularity, recursive path leases for scalably maintaining name-space consistency, and a protocol for consistently performing operations on files managed by separate machines. It also mitigates metadata hotspots via file-field leases and the new mechanism of disjunctive leases. We experimentally show that Farsite can dynamically partition filesystem metadata while maintaining full file-system semantics.
Can smooth view transitions facilitate perceptual constancy in node-link diagrams?
Authors: Maruthappan Shanmugasundaram, Pourang Irani, Carl Gutwin
Venue: Proceedings of Graphics Interface 2007 (2007)

Many visualizations use smoothly animated transitions to help the user interact with information structures. These transitions are intended to preserve perceptual constancy during viewpoint transformations. However, animated transitions also have costs -- they increase the transition time, and they can be complicated to implement -- and it is not clear whether the benefits of smooth transitions outweigh the costs. In order to quantify these benefits, we carried out two experiments that explore the effects of smooth transitions. In the first study, subjects were asked to determine whether graph nodes were connected, and navigated the graph either with or without smooth scene transitions. In the second study, participants were asked to identify the overall structure of a tree after navigating the tree through a viewport that either did or did not use smooth transitions for view changes. The results of both experiments show that smooth transitions can have dramatic benefits for user performance -- for example, participants in smooth transition conditions made half the errors of the discrete-movement conditions. In addition, short transitions were found to be as effective as long ones, suggesting that some of the costs of animations can be avoided. These studies give empirical evidence on the benefits of smooth transitions, and provide guidelines about when designers should use them in visualization systems.
Privacy analysis for data sharing in *nix systems
Authors: Aameek Singh, Ling Liu, Mustaque Ahamad
Venue: Proceedings of the annual conference on USENIX '06 Annual Technical Conference (2006)

Linux and its various flavors (together called *nix) are growing in mainstream popularity and many enterprise infrastructures now are based on *nix platforms. An important component of these systems is the ingrained multi-user support that lets users share data with each other. In this paper, we analyze *nix systems and identify an urgent need for better privacy support in their data sharing mechanisms. In one of our studies it was possible to access over 84 GB of private data at one organization of 836 users, including over 300,000 emails and 579 passwords to financial and other private services websites. The most surprising aspect was the extremely low level of sophistication of the attack. The attack uses no technical vulnerabilities, rather inadequacies of *nix access control combined with user/application's privacy-indifferent behavior.
A time-dependent decision support system for multi-attribute decision-making
Authors: Sixto Ríos-Insua, Antonio Jiménez, Alfonso Mateos
Venue: Integrated Computer-Aided Engineering (2004)

We describe a decision support system including multiple conflicting objectives and with consequences spanning several time periods. The system is supported by an imprecise multiattribute additive utility model, which includes the possibility of different discounting methods, aimed at identifying the optimal strategy by means of interactive multiobjective simulated annealing. The system can be useful for solving problems, including, if necessary, decisions with imprecise consequences over different time periods, which are modelled by means of an objective hierarchy. This objective hierarchy considers appropriate preferences based on judgemental inputs for assessing imprecise individual utility functions and imprecise scaling factors on objectives and attributes, which are aggregated into a scalar or vectorial additive utility function to evaluate the available alternative decisions. The system also includes different sensitivity analyses to check the robustness of the conclusions. Finally, an application to the evaluation of remedial strategies for restoring contaminated aquatic ecosystems illustrates the usefulness and flexibility of this decision support tool.
Pass-efficient algorithms for clustering
Authors: Ravi Kannan
Venue:  (2006)

The proliferation of computational problems involving massive data sets has necessitated the design of computational paradigms that model the extra constraints placed on systems processing very large inputs. Among these algorithmic paradigms, the pass-efficient model captures the constraints that the input may be much too large to fit in main memory for processing, and that system performance is optimized by sequential access to the data in storage. Thus, in the pass-efficient model of computation, an algorithm may make a constant number of sequential passes over read-only input while using a small amount of random access memory. The resources to be optimized are memory, number of passes, and per element processing time. We give pass-efficient algorithms for clustering and finding structure in large amounts of data. Our algorithms have the property that the number of passes allotted is an input parameter to the algorithm. We answer questions regarding the intrinsic tradeoffs between the number of passes used by a pass-efficient algorithm and the amount of random access memory required. Our algorithms use adaptive sampling techniques that are quite general and can be used to solve many massive data set problems. The first family of clustering problems that we consider is learning mixtures of distributions. In these problems, we are given samples drawn according to a probability distribution known as a mixture of distributions, and must reconstruct the density function of the original mixture. Our algorithms show tradeoffs between the number of passes and the amount of memory required: if the algorithm makes a few extra passes, the amount of memory required drops off sharply. We also prove lower bounds on the amount of memory needed by any &ell;-pass randomized algorithm, thus showing that our tradeoff is nearly tight. The second family of clustering problems that we consider is the combinatorial optimization problem of facility location and related problems. Our pass-efficient algorithms for this problem exhibit the same sharp tradeoffs as our algorithm for learning mixtures of distributions. We also give clustering algorithms that are not in the streaming model for partitioning a graph to approximately minimize certain natural objective functions.
Evolving a "Wise" integration system for e-commerce transactions
Authors: Chima Adiele, Sylvanus A. Ehikioya
Venue: Electronic Commerce Research and Applications (2007)

The Web facilitates a global marketplace that provides an economic platform for application developers, merchants and customers to exchange goods and services from a wide range of domains. As a result, large volume of data now resides on the Web. Access to data distributed over the Web is becoming increasingly difficult because of information overload. A system that transcends the amalgamation of data, and provides easy access to data distributed over the Web is necessary. We present WISE, a correctness preserving approach to integration of Web data sources. We describe components of WISE, including a flexible semistructured data model, a common-term vocabulary, and an efficient integration algorithm that automates the integration process. We formally specify these components and show that the global integrated schema is correct, complete, minimal, and understandable.
An Identity-Free and On-Demand Routing Scheme against Anonymity Threats in Mobile Ad Hoc Networks
Authors: Jiejun Kong Xiaoyan Hong Mario Gerla
Venue: IEEE Transactions on Mobile Computing (2007)

Introducing node mobility into the network also introduces new anonymity threats. This important change of the concept of anonymity has recently attracted attentions in mobile wireless security research. This paper presents identity-free routing and on-demand routing as two design principles of anonymous routing in mobile ad hoc networks. We devise ANODR (ANonymous On-Demand Routing) as the needed anonymous routing scheme that is compliant with the design principles. Our security analysis and simulation study verify the effectiveness and efficiency of ANODR.
The little and large of publish/subscribe: ever the twain shall meet?
Authors: Joe Sventek
Venue: Proceedings of the 2007 inaugural international conference on Distributed event-based systems (2007)

Publish/subscribe is a popular event dissemination mechanism, providing anonymous, store-and-forward message distribution. Such systems have been deployed in quite small application environments, such as body area networks for patient health monitoring; they have also been deployed in extremely large distributed application environments, such as stock price distribution systems. The AMUSE project in the UK is a collaboration between computing researchers at the University of Glasgow and Imperial College London. This project is focused on the concept of self-managed cells (SMC) as the basic unit of autonomous computing, and the federation of such cells at different levels of scale. Publish/subcribe implementations form the basis of SMCs at all levels of scale, and the federation of these P/S implementations forms the basis of SMC-SMC interactions. This talk will present the P/S systems at the heart of small and large scale SMCs, and explore their federation. The efficacy of such federations will be discussed, and lessons learned recounted.
Doing more with less: a recipe for rapid IDDQ development
Authors: R. Ackerman
Venue: Proceedings of the 2004 IEEE International Workshop on Defect Based Testing (2004)

This paper describes the method for developing and deploying IDDQ testing on two 0.18 /spl mu/m chips developed at SMA. By using the self-scaling ratio-based IDDQ technique developed by Peter Maxwell, SMA is able to effectively screen defective devices without incurring unnecessary yield penalties. This paper documents the method of generating IDDQ vectors, qualifying them through temperature analysis, characterizing the devices setting the limits, and integrating the final product into the production test. As a case study, the results of this technique are discussed as they pertain to SMA's chips. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
The role of graphical programming languages in teaching DSP
Authors: N. Amir
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 06 (2000)

Graphical programming languages such as Simulink, Hypersignal and others have been coming into use recently for rapid prototyping of DSP algorithms. Using such languages amounts to dragging functional blocks from libraries and connecting them to form a block diagram, which is also a program. Beyond their value to application development, these programming languages are also very useful as classroom teaching aids. In this paper we present a number of useful demonstrations in Simulink. Each of them demonstrates interesting aspects of DSP, and are useful for classroom demonstrations and as a basis for further experimentation by the students. Using them can enhance the students grasp of complicated subjects in DSP, and increase their interest in the subject matter. The major advantages of using Simulink for this purpose is that constructing them requires a relatively small investment of time on the part of the instructor, and that they can easily be extended and experimented on by the students. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player