ppxscal/embedding_network huggingface dataset:
Component Substitutability via Equivalencies of Component-Interaction Automata
Authors: Ivana Černá, Pavlína Vařeková, Barbora Zimmerova
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2007)

We provide a new look at formal aspects of component substitutability (replacement of a component with a new one) and independent implementability (reuse of a component in any system where its implementation satisfies the specification given by the environment), in view of an underlying formalism called Component-interaction automata. Our aim is to offer a formal characterization of preconditions that lead to reconfiguration correctness (proper component substitution and safe independent implementation). Such preconditions then guarantee that the updated system remains equivalent to the former one and hence there is no need to verify it again. The contribution of the paper is twofold. First, we formally define three relations that allows us to compare behaviours of two components with respect to reconfiguration correctness. Namely, the equivalence relation, specification-implementation relation, and substitutability relation. Second, we formally characterize the problem of component substitutability for both equivalent and non-equivalent components, and the problem of independent implementability. The characterizations are captured in several propositions which are proved in the text.
Contractible subgraphs in k-connected graphs
Authors: Zemin Jin, Xingxing Yu, Xiaoyan Zhang
Venue: Journal of Graph Theory (2007)

For a graph G we define a graph T(G) whose vertices are the triangles in G and two vertices of T(G) are adjacent if their corresponding triangles in G share an edge. Kawarabayashi showed that if G is a k-connected graph and T(G) contains no edge, then G admits a k-contractible clique of size at most 3, generalizing an earlier result of Thomassen. In this paper, we further generalize Kawarabayashi's result by showing that if G is k-connected and the maximum degree of T(G) is at most 1, then G admits a k-contractible clique of size at most 3 or there exist independent edges e and f of G such that e and f are contained in triangles sharing an edge and G&#x002F;e&#x002F;f is k-connected. &copy; 2006 Wiley Periodicals, Inc. J Graph Theory 55: 121&ndash;136, 2007
On the feasibility of totally blind channel identification in communication systems using guard intervals
Authors: J. H. Manton
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 01 (2002)

Blind identification techniques estimate the impulse response of a channel by exploiting known finite alphabet or statistical properties of the transmitted symbols. Alternatively, oversampling the output is known to introduce dependencies also exploitable for channel identification. This paper proves the feasibility of estimating the channel by relying instead on the short sequences of zeros, known as guard intervals or zero padding, introduced between transmitted blocks by a number of communication protocols. Since no property of the transmitted information symbols is assumed, the method is called totally blind channel identification. It is proved that totally blind channel identification requires only two received blocks to estimate the channel.
Mailing list archive tools
Authors: Sam Leffler, Melange Tortuba
Venue: Proceedings of the annual conference on USENIX Annual Technical Conference (1997)

Electronic mailing lists are a common forum for discussion on the Internet. Each participant receives a copy of each message posted to the list with an additional copy typically archived at a well-known site for later retrieval. Busy lists and long-running lists can quickly accumulate many messages making it difficult to locate information. Few sites provide mechanisms for the efficient storage or retrieval of information from these archives. The Mailing List Archive (MLA) tools were designed to address these issues. Mail messages are stored in a space-efficient manner and the archive information is processed to create a database that is optimized for fast queries. The MLA tools are designed for use as Computer Gateway Interface (CGI) applications so that archives can be accessed through HTML forms on the World Wide Web. Concurrent update and retrieval are an integral part of the design so that up to date information is always returned in query results.
MC-CDMA systems with cyclic shift spreading codes transmit diversity over two-ray Rayleigh fading channels
Authors: Lingtao Fan, Jian Chen
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 01 (2002)

Transmit diversity is one of the best approaches to combat the fading channels in high data rate wireless systems. We present a new transmit diversity scheme for MC-CDMA systems. It is composed of multiple transmission branches. Each branch transmits the same data symbol synchronously with the same spread code but with different delay. A RAKE receiver is employed in the frequency domain to obtain space diversity gains. Analysis and simulation results show that performance benefits can be achieved compared to conventional MC-CDMA systems in Rayleigh fading channels.
Decolorize: Fast, contrast enhancing, color to grayscale conversion
Authors: Mark Grundland, Neil A. Dodgson
Venue: Pattern Recognition (2007)

We present a new contrast enhancing color to grayscale conversion algorithm which works in real-time. It incorporates novel techniques for image sampling and dimensionality reduction, sampling color differences by Gaussian pairing and analyzing color differences by predominant component analysis. In addition to its speed and simplicity, the algorithm has the advantages of continuous mapping, global consistency, and grayscale preservation, as well as predictable luminance, saturation, and hue ordering properties.
Understanding student confidence as it relates to first year achievement
Authors: M. Besterfield-Sacre
Venue: Proceedings of the 28th Annual Frontiers in Education - Volume 01 (1998)

There has been considerable concern that entering female engineering students begin their studies with less confidence in their abilities than academically equivalent male students. Further, there is concern that this 'under-confidence' problem persists throughout the university experience. As a precursor to a larger cross-institutional study, the authors have investigated this issue in the USA at the University of Pittsburgh, University of Texas-El Paso and North Carolina State University. Using the Pittsburgh Freshman Engineering Attitudes Surveys, they examined the differences between male and female students' self-assessed confidence (relative to five measures) when they began their engineering studies and after one or two semesters of study. In addition, they examined students' confidence and changes in confidence with respect to their entering SAT scores and first year performance. At all three institutions, female students entered with significantly lower confidence in their basic engineering knowledge and skills (one of the five measures) than did their male counterparts, but only continued to exhibit this low confidence at one institution during the freshman year. However, they did not find any consistent, significant relations for the other measures, nor did they find any relations with SAT and performance.
A Look into the Relationship between Knowledge Management and the Knowledge Hierarchies
Authors: Judith Pinn Carlisle
Venue: Proceedings of the 40th Annual Hawaii International Conference on System Sciences (2007)

In 1988, Ackoff made the presidential address to the International Society of General Systems Research and put forth the idea that relationships exist between data, information, knowledge and wisdom and that these relationships are hierarchical in nature. This idea has continued, relatively unchallenged, to the present. This paper suggests that the relationships between data, information, knowledge and wisdom are not hierarchical, nor are they compositional. If the knowledge hierarchies that exist were abandoned, what would be the ramifications? With regard to information systems, such a revision would indicate a great reorganization effort. Yet, in order to maintain current quality of knowledge management systems and achieve future improvement, it would not be amiss to undertake an examination of the knowledge hierarchies. This paper examines what relationships between data, information and knowledge might emerge if the hierarchies were abandoned. It proposes that the nature of knowledge would be understood more clearly, that knowledge is an entity without direct or derived creation from data and especially not from information.
Adaptive acoustic echo cancellation based on FIR and IIR filter banks
Authors: T. Ansahl
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 04 (1999)

We investigate various subband AEC systems in real handsfree situation, including FIR and IIR analysis and synthesis QMF filter banks in a polyphase structure. The adaptation in the subbands is performed by the affine projection algorithm in comparison to the NLMS algorithm. The IIR filters are superior to FIR filters in the sense that they lead to low signal delay and sharp frequency separation. Furthermore the computational complexity is greatly reduced by the use of IIR filters. The results show that splitting the signal into more subbands has advantages. Both wideband and narrowband speech signals have been evaluated.
An improvement on ad-hoc wireless network routing based on AODV
Authors: N. Moghim, F. Hendessi, N. Movehhedinia
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 02 (2002)

Ad-hoc On demand Distance Vector (AODV) is an on-demand protocol, which is designed for ad-hoc networks. Compared with DSR, AODV has more routing overhead in high load networks with high speed of nodes' movement. We try to reduce AODV's routing load by preventing AODV from relying on route request flood more often in route discovery process. Simulation showed that the proposed way could reduce routing overhead and delay of routing in high load networks without any undesirable effects on throughput and delay of packets.
IBM/NC State joint Smalltalk program
Authors: S. de Deugd, B. Nguyen, Y. P. Shan
Venue: Proceedings of the Frontiers in Education Conference on 1995. Proceedings., 1995 vol 1. - Volume 01 (1995)

When faced with a shortage of Smalltalk programming skills, the IBM Lab at Research Triangle Park, NC, USA worked with North Carolina State University to find a solution. What resulted was a joint program for Smalltalk object-oriented education centered around sound engineering and project work. That program now running for over two years has been continually improved by evaluating each semester's results and making appropriate changes. IBM's direct involvement as an industry sponsor included the development of course materials, classroom instruction and project mentoring. This involvement provided IBM engineers first-hand experiences with the students and allowed them to work effectively with NC State to adjust the program. This approach has proved successful in overcoming this technology's steep learning curve, providing students with a foundation of object-oriented skills. The program has created an effective combination of an industry's skill needs and the university's goal of providing a solid engineering education. We believe it could serve as a model for other companies that have specific education and skill requirements.
Linked split-vector quantizer of LPC parameters
Authors: Jianping Pan
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 02 (1996)

In speech coding, several vector quantization (VQ) methods for the LPC (linear predictive coding) parameters have been developed. Because LPC parameters are too dynamic to quantize directly, the LSFs (line spectrum frequencies) are used instead. In this study, we propose the linked split-vector quantizer (LSVQ) where the lower and the upper codebook are selected according to the preselected middle codevector. Using the ordering property of LSFs, LSVQ links three codebooks for the efficient use of the codebook space. Compared with the conventional split-vector quantizer (SVQ), LSVQ increases the usage of codebook space by 10.84%, and shows lower spectral distortion at 23 bits/frame than the SVQ at 24 bits/frame. 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
Blind MMSE equalization: a new direct method
Authors: Mindi Sheng
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 05 (2000)

We propose a blind MMSE equalization algorithm to compute fractionally spaced blind equalizers with arbitrary delay directly from second order statistics of the observations. The algorithm is based on multi-channel linear prediction. Performance analysis demonstrates that our algorithm has higher signal-to-interference-plus-noise-ratio (SINR) than its zero-forcing counter part. Simulations show that our algorithms outperform some typical existing algorithms.
Pluggable authentication modules for Windows NT
Authors: Naomaru Itoi, Peter Honeyman
Venue: Proceedings of the 2nd conference on USENIX Windows NT Symposium - Volume 2 (1998)

To meet the challenge of integrating new methods and technologies into the Internet security framework, it is useful to hide low-level authentication mechanisms from application programmers, system administrators, and users, replacing them with abstractions at a higher level. The Pluggable Authentication Method approach popular in Linux, Solaris, and CDE offers one such abstraction. To implement PAM in NT, we replaced the standard Graphical Identification and Authentication module with one that processes PAM tables. This provides security administrators with a flexible tool to plan and implement authentication policy across a wide range of computing platforms. GINA is woven into the NT logon procedure, making it a difficult module to test and debug. Our PAM-based GINA eases this problem by allowing new authentication mechanisms to be replaced and tested without forcing a reboot.
Variations of the group quiz that promote collaborative learning
Authors: C. F. Yokomoto
Venue: Proceedings of the Frontiers in Education Conference,1997. on 27th Annual Conference. Teaching and Learning in an Era of Change. - Volume 01 (1997)

In this paper, we demonstrate how variations of the in-class group quiz can resolve two difficulties often reported by instructors as they contemplate the use of collaborative learning techniques in lecture classes. The two difficulties we refer to are: (1) encouraging student acceptance of active learning and (2) making the transition from lecturer to facilitator. In this paper, we show how these two difficulties can be resolved by converting familiar, in-class, individual quizzes to group quizzes. In addition, we show how group quizzes can play additional roles in the collaborative learning process such as assisting in the development of instructional materials that enhance learning, coaching students in the development of learning skills, promoting interaction among students, and reducing students' anxiety with quizzes. Finally, we present statistical data that defends the use of group quizzes in the grading process.
Cross Layer Routing for Multihop Cellular Networks
Authors: G. Kannan, S. N. Merchant, U. B. Desai
Venue: Proceedings of the 21st International Conference on Advanced Information Networking and Applications Workshops - Volume 02 (2007)

We propose a unified cross layer routing protocol with multiple constraints for CDMA multihop cellular networks (MCN). Multiple constraints are imposed on intermediate relay node selection and source to destination path selection. The relay node constraints for routing protocol design are cooperation, interference caused to other nodes and sufficient neighborhood connectivity. Path constraints for routing are end-to-end throughput and end-to-end delay. We do not assume full cooperation for call forwarding and present a facile incentive mechanism to motivate the cooperation for call forwarding. We incorporate a realistic mobility model and dynamic call dropping notion in our system. Flat fading i.i.d Rayleigh channel is assumed between mobile nodes. Simulation results show that the proposed algorithm reduces intracell interference by more than 70% as compared to nearest neighbour routing algorithm. Furthermore, the proposed algorithm achieves better throughput and maintains the delay at tolerable level. We also demonstrate that the proposed routing algorithm is superior to many standard routing protocols.
Procedural generation of stylized 2D maps
Authors: Mores Prachyabrued, Timothy E. Roden, Ryan G. Benton
Venue: Proceedings of the international conference on Advances in computer entertainment technology (2007)

Outdoor worlds are often the setting for games and game worlds are often accompanied by a stylized version of the world drawn by an artist as a 2D map. Procedurally generating the terrain allows games to have a higher replay value. A limitation of procedural terrain generation is an artistic map of the terrain cannot be created by an artist beforehand. We propose an algorithm for generating a stylized 2D map from a simple procedurally generated 2D basis map. Our algorithm could be used in a game to generate stylized maps at execution time or in an offline application to serve as a guideline for an artist.
Dense Stereo Range Sensing with Marching Pseudo-Random Patterns
Authors: Danick Desjardins, Pierre Payeur
Venue: Proceedings of the Fourth Canadian Conference on Computer and Robot Vision (2007)

As an extension to classical structured lighting techniques, the use of bi-dimensional pseudo-random color codes is explored to perform range sensing with variable density from a stereo calibrated rig and a projector. Pseudo-random codes are used to create artificial textures on a scene which are extracted and grouped in a confidence map to ensure reliable feature matching between pairs of images taken from two cameras. Depth estimation is performed on corresponding points with progressive refinement as the pseudo-random pattern projection is marched over the scene to increase the density of matched features, and achieve dense 3D reconstruction. The potential of bi-dimensional pseudo-random color patterns for structured lighting is demonstrated in terms of patterns computation, ease of extraction, matching confidence level, as well as density of depth estimation for 3D reconstruction.
Uniqueness of Constrained Viscosity Solutions in Hybrid Control Systems
Authors: Minyi Huang
Venue: SIAM Journal on Control and Optimization (2007)

We study constrained viscosity solutions with an unbounded growth for a class of first order Hamilton-Jacobi-Bellman equations arising in hybrid control systems. To deal with the boundary constraint and rapid growth of the solutions, we construct a particular set of test functions and under very mild conditions establish a comparison theorem which gives the estimate of distance between the subsolution and the supersolution. The comparison theorem implies uniqueness of the constrained viscosity solution if its existence is ensured; and under some additional assumptions we give an existence result by showing that the value function is a constrained viscosity solution. We then apply the obtained uniqueness results to an optimal scheduling problem and finally to stochastic manufacturing systems.
Combining events and threads for scalable network services implementation and evaluation of monadic, application-level concurrency primitives
Authors: Peng Li, Steve Zdancewic
Venue: ACM SIGPLAN Notices (2007)

This paper proposes to combine two seemingly opposed programming models for building massively concurrent network services: the event-driven model and the multithreaded model. The result is a hybrid design that offers the best of both worlds--the ease of use and expressiveness of threads and the flexibility and performance of events. This paper shows how the hybrid model can be implemented entirely at the application level using concurrency monads in Haskell, which provides type-safe abstractions for both events and threads. This approach simplifies the development of massively concurrent software in a way that scales to real-world network services. The Haskell implementation supports exceptions, symmetrical multiprocessing, software transactional memory, asynchronous I/O mechanisms and application-level network protocol stacks. Experimental results demonstrate that this monad-based approach has good performance: the threads are extremely lightweight (scaling to ten million threads), and the I/O performance compares favorably to that of Linux NPTL. tens of thousands of simultaneous, mostly-idle client connections. Such massively-concurrent programs are difficult to implement, especially when other requirements, such as high performance and strong security, must also be met.
Supporting dependable group-oriented mobile transactions: redundancy-based architecture and performance
Authors: Upkar Varshney
Venue: International Journal of Network Management (2007)

Several of the emerging mobile commerce services, such as mobile auctions, mobile financial services, and multiparty interactive games, will require support for dependable transactions. This is a difficult challenge because of both intermittent connectivity and potential failures in wireless infrastructure. In this paper, we present a multinetwork access-based wireless architecture and related protocols to support dependable transactions. The key idea is to allow group users to utilize access to one or more wireless networks to complete different steps of a transaction. This allows for transactions to be completed even under time- and location-dependent connectivity problems and network failures. The performance results show that access to multiple wireless networks leads to very high transaction completion probability even when individual wireless networks do not offer continuous and/or highly available access. The transaction completion probability is found to be dependent on the group size and number of steps in a transaction, and the same level of dependable performance for transactions can be achieved by increasing the number of wireless networks or improved access to individual networks. The overhead for multi-network access can be further reduced by creating preferred wireless networks and by reducing the number of critical users in different transaction stages.
A Language-Independent API for Unstructured Mesh Access and Manipulation
Authors: Carl Ollivier-Gooch, Lori Freitag Diachin, Mark S. Shephard, Timothy Tautges
Venue: Proceedings of the 21st International Symposium on High Performance Computing Systems and Applications (2007)

Software for numerical solution of partial differential equations requires accessing, manipulating, and often modifying information about the geometry of the computational domain, the mesh used for the simulation, and discrete data stored on that mesh. Typically, applications programmers would prefer to avoid the difficulty and complexity of creating their own modules for tasks like interacting with multiple geometric modelers, mesh adaptation, and optimization algorithms, rightly preferring instead to focus on the problem physics and on studying the physical results that the code produces. Ideally, these modules would be provided by experts in CAD modeling, meshing, and optimization, and written so that they can use the application's data regardless of the data structures used by the application. This paper describes a language- and data-structure-independent interface supporting query and modification of mesh data conforming to a general abstract data model.