ppxscal/embedding_network huggingface dataset:
Circuit-wise buffer insertion and gate sizing algorithm with scalability
Authors: Zhanyuan Jiang, Weiping Shi
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

Most existing buffer insertion algorithms, such as van Ginneken's algorithm, consider individual nets and therefore often result in high buffer cost due to lack a global view. Thus, circuit-wise buffering is necessary to reduce buffer cost. Recently, some circuit-wise buffering algorithms are proposed. However, these algorithms are based on heuristics which are not scalable in handling large circuits. In this paper, we present a scalable circuit-wise algorithm with three novel features. (1) A linear modeling of nonlinear delay versus cost tradeoff. Due to the similar nature of buffer insertion and gate sizing, gate sizing is handled in such a manner. (2) A dynamic critical sink selection procedure to solve multiple-sink net. Multiple-sink nets have been problems for previous circuit-wise buffering algorithms. (3) A circuit partition technique to divide the circuit into sub-circuits and apply divide-and-conquer scheme. This technique provides high scalability for the algorithm. Experiments on ISCAS85 circuits show that the new algorithm achieves 17X speedup compared with Sze's path based algorithm. In the meantime, it saves 16.0% buffer cost and 4.9% gate cost without increasing circuit delay. Furthermore, the running time of a testcase in ITC99 with approximate one hundred thousand gates is less than 11 minutes, which demonstrates the scalability of the new algorithm.
Structure in locally optimal solutions
Authors: M. W. Krentel
Venue: Proceedings of the 30th Annual Symposium on Foundations of Computer Science (1989)

A class of local search problems, PLS (polynomial-time local search), as defined by D.S. Johnson et al. (see J. Comput. Syst. Sci., vol.37, no.1, p.79-100 (1988)) is considered. PLS captures much of the structure of NP problems at the level of their feasible solutions and neighborhoods. It is first shown that CNF (conjunctive normal form) satisfiability is PLS-complete, even with simultaneously bounded size clauses and bounded number of occurrences of variables. This result is used to show that traveling salesman under the k-opt neighborhood is also PLS-complete. It is argued that PLS-completeness is the normal behavior of NP-complete problems.
Multi-strategy ensemble particle swarm optimization for dynamic optimization
Authors: Weilin Du, Bin Li
Venue: Information Sciences: an International Journal (2008)

Optimization in dynamic environments is important in real-world applications, which requires the optimization algorithms to be able to find and track the changing optimum efficiently over time. Among various algorithms for dynamic optimization, particle swarm optimization algorithms (PSOs) are attracting more and more attentions in recent years, due to their ability of keeping good balance between convergence and diversity maintenance. To tackle the challenges of dynamic optimization, several strategies have been proposed to enhance the performance of PSO, and have gained success on various dynamic optimization problems. But there still exist some issues in dynamic optimization which need to be studied carefully, i.e. the robustness of the algorithm to problems of various dynamic features. In this paper, a new multi-strategy ensemble particle swarm optimization (MEPSO) for dynamic optimization is proposed. In MEPSO, all particles are divided into two parts, denoted as part I and part II, respectively. Two new strategies, Gaussian local search and differential mutation, are introduced into these two parts, respectively. Experimental analyses reveal that the mechanisms used in part I can enhance the convergence ability of the algorithm, while mechanisms used in part II can extend the searching area of the particle population to avoid being trapped into the local optimum, and can enhance the ability of catching up with the changing optimum in dynamic environments. The whole algorithm has few parameters that need to be tuned, and all of them are not sensitive to problems. We compared MEPSO with other PSOs, including MQSO, PHPSO and Standard PSO with re-initialization, on moving peaks Benchmark and dynamic Rastrigin function. The experimental results show that MEPSO has pretty good performance on almost all testing problems adopted in this paper, and outperforms other algorithms when the dynamic environment is unimodal and changes severely, or has a great number of local optima as dynamic Rastrigin function does.
Prescribed Learning of Indexed Families
Authors: Sanjay Jain, Frank Stephan, Ye Nan
Venue: Fundamenta Informaticae (2008)

This work extends studies of Angluin, Lange and Zeugmann on how learnability of a language class depends on the hypothesis space used by the learner. While previous studies mainly focused on the case where the learner chooses a particular hypothesis space, the goal of this work is to investigate the case where the learner has to cope with all possible hypothesis spaces. In that sense, the present work combines the approach of Angluin, Lange and Zeugmann with the question of how a learner can be synthesized. The investigation for the case of uniformly r.e. classes has been done by Jain, Stephan and Ye [6]. This paper investigates the case for indexed families and gives a special attention to the notions of conservative and non U-shaped learning.
Distributed Key Management Technique for Reliable Secure Group Communication
Authors: A. S. Poornima, B. B. Amberker
Venue: Proceedings of the Fifth International Conference on Information Technology: New Generations (2008)

In tree-based hierarchical key management schemes, scalability is achieved by reducing the number of messages exchanged during a rekeying operation. A single server manages the entire tree structure in such schemes. Failure of that server leads to single point failure which interrupts the group communication. In this paper we propose a method to avoid single point failure by distributing user information among set of X number of servers and use (t,X) threshold scheme to reconstruct the tree. The new auxiliary keys and group key are computed partly by the users which reduces number of encryptions required to communicate new set of keys to the remaining group members.
Trust Mechanism in Distributed Access Control Model of P2P Networks
Authors: Lei Wang, Yanqin Zhu, Lanfang Jin, Xizhao Luo
Venue: Proceedings of the Seventh IEEE/ACIS International Conference on Computer and Information Science (icis 2008) (2008)

Peer-to-peer network technologies have gained popularity without the need for centralized servers. With the consistent development of the network, the existing techniques about access control could not resolve the security issues in P2P networks perfectly. How to realize the trust mechanism in access control system is an important subject of P2P security research. In this paper, we analyze the lack of trust mechanism in the existing access control models, and present a recommendation trust model based on reputation. We introduce the related concepts in the trust model and explain the mechanism of trust. Then, a protocol of trust query is designed and calculations about trust are given. At last, we validate the availability of the trust model, and applied it in the existing access control model. The combining of trust mechanism and access control technologies makes the P2P networks securer.
A comparison of thin film microrefrigerators based on Si/SiGe superlattice and bulk SiGe
Authors: Y. Ezzahri, G. Zeng, K. Fukutani, Z. Bian, A. Shakouri
Venue: Microelectronics Journal (2008)

Most of the conventional thermal management techniques can be used to cool the whole chip. Since thermal design requirements are mostly driven by the peak temperatures, reducing or eliminating hot spots could alleviate the design requirements for the whole package. Monolithic solid-state microcoolers offer an attractive way to eliminate hot spots. In this paper, we review theoretical and experimental cooling performance of silicon-based microrefrigerators on a chip. Both Si/SiGe superlattice and also bulk SiGe thin film devices have been fabricated and characterized. Direct measurement of the cooling along with material characterization allows us to extract the key factors limiting the performance of these microrefrigerators. Although Si/SiGe superlattice has larger thermoelectric power factor, the maximum cooling of thin film refrigerators based on SiGe alloys are comparable to that of superlattices. This is due to the fact that the superlattice thermal conductivity is larger than bulk SiGe alloy by about 30%.
Report on the XML mining track at INEX 2007 categorization and clustering of XML documents
Authors: Ludovic Denoyer, Patrick Gallinari
Venue: ACM SIGIR Forum (2008)

This report concerns the last edition of the XML Mining Track at INEX 2007. A preceding report has been already published concerning the two preceding editions of the track. We present here the new corpus used for this third phase and briefly describe the models and the results obtained by the different participants.
The use of Second Life for distance education
Authors: Tim Ritzema, Billy Harris
Venue: Journal of Computing Sciences in Colleges (2008)

This paper explores the feasibility of utilizing the vaunted Second Life environment for distance education in the area of computer science. Two sets of user groups were enlisted to determine whether the virtual environment was suitable for conveying concepts ranging from the simplistic to the complex. Due to the overwhelmingly positive responses provided via the anonymous surveying of the participants, it can be determined that the Second Life platform is indeed a viable solution for distance education in the area of computer science.
The effect of using problem-solving software tutors on the self-confidence of female students
Authors: Amruth N. Kumar
Venue: Proceedings of the 39th SIGCSE technical symposium on Computer science education (2008)

We examined whether using problem-solving software tutors in Computer Science I can help improve the self-confidence of female students. We analyzed the data collected by five software tutors in spring 2006. We found that 1) the self-confidence of female Computer Science I students before using the software tutors was in many cases lower than that of male students, as has been stated in prior literature; 2) Using problem-solving software tutors improved the self-confidence of female students to be on par with that of male students when female students started with lower prior self-confidence. Since researchers have suggested that self-confidence is one of the factors contributing to the shrinking pipeline, problem-solving software tutors can be used to improve the retention of female students in Computer Science.
Historiographic Conceptualization of Information: A Critical Survey
Authors: Bernard Dionysius Geoghegan
Venue: IEEE Annals of the History of Computing (2008)

The historical pedigree and meaning of "information" has been hotly contested since its scientific definition in the 1940s. Scientists have authored very different explanations for the origins of informational research, the scope of information theory, and the historical significance of its findings. This survey classifies the historical literature into genres, offering a view into the changing environment of computer research.
Customer analytics projects: addressing existing problems with a process that leads to success
Authors: Inna Kolyshkina, Simeon Simoff
Venue: Proceedings of the sixth Australasian conference on Data mining and analytics - Volume 70 (2007)

This article explicitly outlines an approach designed to allow optimal utilisation of Analytics in the industry setting. The paper focuses on the key stages of the Analytics process that have not been identified in previous Analytics methodologies and draws on industry, consulting and research experience to show that correct design of the project trajectory can allow the industry to fully realise the benefits that Analytics has to offer. As the case studies provided demonstrate, it is often the skipping of key stages, especially the preliminary analysis stage, that are currently responsible for preventing success of an Analytics project. It has been shown how, using the outlined approach, project can achieve maximum effectiveness and business buy-in.
Testing the accuracy of a data assimilation algorithm
Authors: Z. Zlatev, J. Brandt
Venue: International Journal of Computational Science and Engineering (2007)

Variational data assimilation techniques have been successfully used in connection with comprehensive research projects in different fields of science and engineering. The use of the variational data assimilation approach is becoming more and more popular also in the attempts to improve the accuracy of the results obtained by running large-scale air pollution models. Different tests were carried out in order both to check the ability of the data assimilation procedures to improve the initial concentrations and to start building up a benchmark for testing the performance of these procedures on different modern high-speed computers. Selected results from these tests will be presented and discussed in this paper.
Secret Key Extraction in Ultra Wideband Channels for Unsynchronized Radios
Authors: Masoud Ghoreishi Madiseh, Michael L. McGuire, Stephen W. Neville, Ali Asghar Beheshti Shirazi
Venue: Proceedings of the Communication Networks and Services Research Conference (2008)

Secure communications in UWB based on cryptographic keys generated from channel measurements without a trusted third party have been developed. The fine time resolution of UWB allows high levels of mutual information to be obtained by a given A and B through independent characterizations of their shared communication channel. This mutual information determines the maximum secret key rate available to A and B. Since UWB channel gains change drastically with small antenna movements, it is inherently difficult for eavesdroppers to obtain channel measurements and reduce the secret key rate. In essence, UWB can provide spatial-temporal specific secret keys. Upper bounds on the secret key rate for standard UWB channels are calculated. It is demonstrated that high secure key generation rates are possible. It is shown that these key rates can be generated over a wide range of signal to noise ratios and channel synchronization errors.
Low latency wireless ad hoc networking: power and bandwidth challenges and a solution
Authors: Nima Sarshar, Behnam A. Rezaei, Vwani P. Roychowdhury
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

This paper is concerned with the scaling of the number of relay nodes (i.e., hops) individual messages have to transit through in a large-scale wireless ad hoc network (WANET); we call this hop-count as network latency (NL). A large network latency affects all aspects of data communication in a WANET, including an increase in delay, packet loss, and the power needed to process and store messages in nodes lying on the relay path. We consider network management and data routing challenges in WANETs with scalable network latency, e.g., when NL increases only polylogarithmically in the network size. On the physical side, reducing network latency imposes a significantly higher power and bandwidth demand on nodes, and are captured in a set of new bounds derived in this paper. On the protocol front, designing distributed routing protocols that can guarantee the delivery of data packets within a scalable number of hops is a challenging task. To solve this, we introduce multiresolution randomized hierarchy (MRRH), a novel power and bandwidth efficient WANET protocol with scalable network latency. MRRH uses a randomized algorithm for building and maintaining a random hierarchical network topology, which together with the proposed routing algorithm, can guarantee efficient delivery of data packets in the wireless network. For a network of size N, MRRH can provide an average latency of only O(log3 N). The power consumption and bandwidth requirements of MRRH are shown to be nearly optimal for the latency it provides. Therefore, MRRH is a provably efficient candidate for truly large-scale wireless ad hoc networking.
Merging equivalent contexts for scalable heap-cloning-based context-sensitive points-to analysis
Authors: Guoqing Xu, Atanas Rountev
Venue: Proceedings of the 2008 international symposium on Software testing and analysis (2008)

A context-sensitive points-to analysis maintains separate points-to relationships for each possible (abstract) calling context of a method. Previous work has shown that a large number of equivalence classes exists in the representation of calling contexts. Such equivalent contexts provide opportunities for context-sensitive analyses based on binary decision diagrams (BDDs), in which BDDs automatically merge equivalent points-to relationships. However, the use of a BDD ``black box'' introduces additional overhead for analysis running time. Furthermore, with heap cloning (i.e., using context-sensitive object allocation sites), BDDs are not as effective because the number of equivalence classes increases significantly. A further step must be taken to look inside the BDD black box to investigate where the equivalence comes from, and what tradeoffs can be employed to enable practical large-scale heap cloning. This paper presents an analysis for Java that exploits equivalence classes in context representation. For a particular pointer variable or heap object, all abstract contexts within an equivalence class can be merged. This technique naturally results in a new non-BDD context-sensitive points-to analysis. Based on these equivalence classes,the analysis employs a last-k-substring merging approach to define scalability and precision tradeoffs. We show that small values for k can enable scalable heap cloning for large Java programs. The proposed analysis has been implemented and evaluated on a large set of Java programs. The experimental results show improvements over an existing 1-object-sensitive analysis with heap cloning, which is the most precise scalable analysis implemented in the state-of-the-art Paddle analysis framework. For computing a points-to solution for an entire program, our approach is an order of magnitude faster compared to this BDD-based analysis and to a related non-BDD refinement-based analysis.
Route optimization schemes in mobile networks: a theoretical and empirical analysis
Authors: Sahibzada Ahmed Noor, Kashif Azim Janjua, Lin Zhang
Venue: Proceedings of the 4th international conference on mobile technology, applications, and systems and the 1st international symposium on Computer human interaction in mobile technology (2007)

This paper targets network mobility (NEMO) issues from the scope of route optimization. The aim is to explore route optimization (RO) schemes in NEMO. After discussing the need of route optimization in NEMO, available solutions are discussed and a quantitative analysis is provided. Still a lot of work is requires to be done in the field of route optimization in NEMO. All these issues are explained to provide a future course of research in this field.
A dual-time vector clock based synchronization mechanism for key-value data in the SILENUS file system
Authors: Max Berger, Michael Sobolewski
Venue: Proceedings of the 13th International Conference on Parallel and Distributed Systems - Volume 02 (2007)

The SILENUS federated file system was developed by the SORCER research group at Texas Tech University. The federated file system with its dynamic nature does not require any configuration by the end users and system administrators. The SILENUS file system provides support for disconnected operation. To support disconnected operation a relevant synchronization mechanism is needed. This mechanism must detect and order events properly. It must detect also possible conflicts and resolve these in a consistent manner. This paper describes the new synchronization mechanism needed for providing data consistency. It introduces dual-time vector clocks to order events and detect conflicts. A conflict resolution algorithm is defined that does not require user interactions. It introduces the switchback problem and how it can be avoided. The synchronization mechanisms presented in this paper can be adapted to synchronize any key-value based data in any distributed system.
The vocalsearch music search engine
Authors: Bryan Pardo, David Little, Rui Jiang, Hagai Livni, Jinyu Han
Venue: Proceedings of the 8th ACM/IEEE-CS joint conference on Digital libraries (2008)

The VocalSearch system is a music search engine developed at Northwestern University and available on the internet (vocalsearch.org). This system lets the user query for the desired song in a number of ways: sung queries, queries entered as music notation, and text-based lyrics search. Users are also able to contribute songs to the system, making them searchable for future users. The result is a flexible system that lets the user find the song using their preferred modality (music notation, text, music notation). This demonstration lets users try out the VocalSearch system.
Heterogeneous multi-channel wireless networks: routing and link layer protocols
Authors: Vartika Bhandari, Nitin H. Vaidya
Venue: ACM SIGMOBILE Mobile Computing and Communications Review (2008)

We consider multi-channel wireless networks where nodes may be equipped with heterogeneous radios, each potentially capable of operation on a limited portion of the total available spectrum. Moreover even the channels may not all be identical; they may have potentially different propagation characteristics, and may support different sets of transmission rates. Much prior research on multi-channel networks has assumed identical channels and radio capabilities. However heterogeneity of channels and radios introduces a host of new issues that must be handled. In recent theoretical work we considered asymptotic transport capacity of multi-channel networks of single-radio nodes subject to switching constraints. This constitutes a class of instances involving heterogeneous radios, albeit identical channels. We leverage some of the insights obtained from our theoretical results, and now consider a more general model involving heterogeneity of radios and channels. We identify the key issues that differentiate heterogeneous multi-channel wireless networks, and describe a design framework for routing and channel assignment.