ppxscal/embedding_network huggingface dataset:
Morse Decompositions for General Dynamical Systems and Differential Inclusions with Applications to Control Systems
Authors: Desheng Li
Venue: SIAM Journal on Control and Optimization (2007)

The Morse decomposition theory for single-valued dynamical systems is extended to general dynamical systems and differential inclusions. Relations between chain recurrent sets, chain recurrent components (chain control sets), and Morse decompositions for open-loop systems are discussed. The robustness of feedback laws of closed-loop systems with respect to small time delays and sample-hold controls is also addressed.
On Approximate Majority and Probabilistic Time
Authors: Emanuele Viola
Venue: Proceedings of the Twenty-Second Annual IEEE Conference on Computational Complexity (2007)

We prove new results on the circuit complexity of Approximate Majority, which is the problem of computing Majority of a given bit string whose fraction of 1's is bounded away from 1/2 (by a constant). We then apply these results to obtain new relationships between probabilistic time, BPTime (t), and alternating time, \Sigma_{O(1)}Time (t). Our main results are the following: 1. We prove that (2^n^0.1)-size depth-3 circuits for Approximate Majority on n bits have bottom fan-in \Omega(log n). As a corollary we obtain that BPTime (t) \not\subseteq\Sigma_{2}Time (o(t^2)) with respect to some oracle. This complements the result that BPTime (t) \subseteq\Sigma_{2}Time (t^2 \cdot poly log t) with respect to every oracle (Sipser and Gacs, STOC '83; Lautemann, IPL '83). 2. We prove that Approximate Majority is computable by uniform polynomial-size circuits of depth 3. Prior to our work, the only known polynomial-size depth-3 circuits for Approximate Majority were non-uniform (Ajtai, Ann. Pure Appl. Logic '83). We also prove that BPTime (t) \subseteq \Sigma_{3}Time (t \cdot poly log t). This complements our results in (1). 3. We prove new lower bounds for solving QSAT_3 \in \Sigma_{3}Time (n \cdot poly log n) on probabilistic computational models. In particular, we prove that solving QSAT_3 requires time n^{1+\Omega(1)} on Turing machines with a random-access input tape and a sequentialaccess work tape that is initialized with random bits. No lower bound was previously known on this model (for a function computable in linear space).
Feedback Redundancy: A Power Efficient SEU-Tolerant Latch Design for Deep Sub-Micron Technologies
Authors: M. Fazeli, A. Patooghy, S. G. Miremadi, A. Ejlali
Venue: Proceedings of the 37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (2007)

The continuous decrease in CMOS technology feature size increases the susceptibility of such circuits to single event upsets (SEU) caused by the impact of particle strikes on system flip flops. This paper presents a novel SEU-tolerant latch where redundant feedback lines are used to mask the effects of SEUs. The power dissipation, area, reliability, and propagation delay of the presented SEU-tolerant latch are analyzed by SPICE simulations. The results show that this latch consumes about 50% less power and occupies 42% less area than a TMR-latch. However, the reliability and the propagation delay of the proposed latch are still the same as the TMR-latch.the reliability of the proposed latch is also compared with other SEU-tolerant latches.
Geovisualization and synergies from InfoVis and Visual Analytics
Authors: Gennady Andreinko, Mikael Jern, Jason Dykes, Sara Fabrikant, Chris Weaver
Venue: Proceedings of the 11th International Conference Information Visualization (2007)

Geovisualization (GeoViz) is an intrinsically complex process. The analyst needs to look at data from various perspectives and at various scales, from "seeing the whole" to "attending to particulars" (Andrienko and Andrienko 2006). The analyst is also supposed to "see in relation", i.e. make numerous comparisons. This inherent complexity is multiplied by the complexity of the data that is explored and analyzed. The complex, multivariate data structure and heterogeneous components of most contemporary datasets necessitate a combined use of multiple techniques and approaches. There is no single visualization method capable to show "the whole". The analyst has to decompose this whole into views, examine these views and then try to synthesize the whole picture from the partial views. Also, because of large data volumes, we must use methods capable of simultaneously providing an overall view and exposing various "particulars". Looking for "particulars" requires therefore different techniques than "seeing the whole". Some existing visualization tools such as GeoVista and CommonGIS have successfully demonstrated the advantage of multiple-linked views and the use of information visualization (InfoViz) methods such as Parallel Coordinates and Heat maps to explore spatial multivariate data.
A Self-organized Personal Network Architecture
Authors: Weidong Lu, Yanying Gu, R. V. Prasad, Anthony Lo, Ignas Niemegeers
Venue: Proceedings of the Third International Conference on Networking and Services (2007)

This paper presents a self-organized architecture for personal networks. Personal Network (PN) is a user centric enabler for the next generation networks and services, which is dynamic in composition and involves heterogeneous networking technologies.One of the main research issues in the development of PNs is self-organization in order to be adaptive to the dynamics and heterogeneity of PNs. A PN architecture that consists of different self-organized functions is proposed in this paper. In addition, a personal network clustering protocol is proposed as one of the self-organized functions that forms a stable personal cluster and selects a master node of that personal cluster with a longer lifetime.
Towards Guaranteed QoS in Mesh Networks: EmulatingWiMAX Mesh over WiFi Hardware
Authors: Petar Djukic, Shahrokh Valaee
Venue: Proceedings of the 27th International Conference on Distributed Computing Systems Workshops (2007)

Currently deployed wireless mesh networks are based on 802.11, WiFi, technology, which is not efficient in multihop scenarios. We present a method for embedding 802.16 packets into 802.11 broadcast packets and padding the 802.11 broadcast payload, so that the broadcasts are aligned to 802.16 TDMA frame boundaries. Our method requires only software changes on the nodes using 802.11a for mesh communications. This means that the mesh networks installed with 802.11a hardware today can be upgraded with a software patch to take advantage of 802.16 MCF and do not have to wait for hardware upgrades to 802.11s. We show that despite the addition of the padding, emulated 802.16 has bandwidths comparable to the bandwidth achievable with 802.16 hardware. The efficiency of the hybrid system is significantly higher than the efficiency of 802.11 based systems. The new system can also provide deterministic guarantees on link bandwidths since it takes advantage of scheduled wireless access with 802.16 MCF. We use ns2 simulations to show the improved efficiency and guaranteed link bandwidth of the 802.11 based hardware using the emulated 802.16 MCF.
The problem of thirteen spheres - a proof for undergraduates
Authors: H. Maehara
Venue: European Journal of Combinatorics (2007)

The purpose of this note is to present an elementary proof of the fact that no more than twelve unit balls can simultaneously touch a unit ball in 3-space, a proof that is accessible for undergraduates.
Limits on the Hardness of Lattice Problems in \ell _p Norms
Authors: Chris Peikert
Venue: Proceedings of the Twenty-Second Annual IEEE Conference on Computational Complexity (2007)

We show that several recent "positive" results for lattice problems in the \ell _2 norm also hold in \ell _p norms, for p \ge 2. In particular, for lattices of dimension n:Approximating the shortest and closest vector in the \ell _p norm to within \tilde O (\sqrt n) factors is contained in coNP.Approximating the length of the shortest vector in the \ell _p norm to within \tilde O(n) factors reduces to the average-case problems studied in related works (Ajtai, STOC 1996; Micciancio and Regev, FOCS 2004; Regev, STOC 2005). These results improve upon prior understanding of \ell _p norms by up to \sqrt n factors. Taken together, they can be viewed as a partial converse to recent reductions from the \ell _2 norm to \ell _p norms (Regev and Rosen, STOC 2006). One of our main technical contributions is a very general analysis of Gaussian distributions over lattices, which may be of independent interest. Our proofs employ analytical techniques of Banaszczyk which, to our knowledge, have yet to be exploited in computer science.
A flexible and efficient application programming interface (API) for a customizable proxy cache
Authors: Vivek S. Pai, Alan L. Cox, Vijay S. Pai, Willy Zwaenepoel
Venue: Proceedings of the 4th conference on USENIX Symposium on Internet Technologies and Systems - Volume 4 (2003)

This paper describes the design, implementation, and performance of a simple yet powerful Application Programming Interface (API) for providing extended services in a proxy cache. This API facilitates the development of customized content adaptation, content management, and specialized administration features. We have developed several modules that exploit this API to perform various tasks within the proxy, including a module to support the Internet Content Adaptation Protocol (ICAP) without any changes to the proxy core. The API design parallels those of high-performance servers, enabling its implementation to have minimal overhead on a high-performance cache. At the same time, it provides the infrastructure required to process HTTP requests and responses at a high level, shielding developers from low-level HTTP and socket details and enabling modules that perform interesting tasks without significant amounts of code. We have implemented this API in the portable and high-performance iMimic DataReactorTM proxy cache1. We show that implementing the API imposes negligible performance overhead and that realistic content-adaptation services achieve high performance levels without substantially hindering a background benchmark load running at a high throughput level.
Optimizing grid site manager performance with virtual machines
Authors: Ludmila Cherkasova, Diwaker Gupta, Eygene Ryabinkin, Roman Kurakin, Vladimir Dobretsov, Amin Vahdat
Venue: Proceedings of the 3rd conference on USENIX Workshop on Real, Large Distributed Systems - Volume 3 (2006)

Virtualization can enhance the functionality and ease the management of current and future Grids by enabling on-demand creation of services and virtual clusters with customized environments, QoS provisioning and policy-based resource allocation. In this work, we consider the use of virtual machines (VMs) in a data-center environment, where a significant portion of resources from a shared pool are dedicated to Grid job processing. The goal is to improve efficiency while supporting a variety of different workloads. We analyze workload data for the past year from a Tier-2 Resource Center at the RRC Kurchatov Institute (Moscow, Russia). Our analysis reveals that a large fraction of Grid jobs have low CPU utilization, which suggests that using virtual machines to isolate execution of different Grid jobs on the shared hardware might be beneficial for optimizing the data-center resource usage. Our simulation results show that with only half the original infrastructure employing VMs (50 nodes and four VMs per node) we can support 99% of the load processed by the original system (100 nodes). Finally, we describe a prototype implementation of a virtual machine management system for Grid computing.
Windows scheduling as a restricted version of bin packing
Authors: Amotz Bar-Noy, Richard E. Ladner, Tami Tamir
Venue: ACM Transactions on Algorithms (TALG) (2007)

Given is a sequence of n positive integers w1,w2,&hellip;,wn that are associated with the items 1,2,&hellip;n, respectively. In the windows scheduling problem, the goal is to schedule all the items (equal-length information pages) on broadcasting channels such that the gap between two consecutive appearances of page i on any of the channels is at most wi slots (a slot is the transmission time of one page). In the unit-fractions bin packing problem, the goal is to pack all the items in bins of unit size where the size (width) of item i is 1/wi. The optimization objective is to minimize the number of channels or bins. In the offline setting, the sequence is known in advance, whereas in the online setting, the items arrive in order and assignment decisions are irrevocable. Since a page requires at least 1/wi of a channel's bandwidth, it follows that windows scheduling without migration (i.e., all broadcasts of a page must be from the same channel) is a restricted version of unit-fractions bin packing. Let H &equals; &lceil;&sumi&equals;1n(1/wi) be the bandwidth lower bound on the required number of bins (channels). The best-known offline algorithm for the windows scheduling problem used H &plus; O(ln H) channels. This article presents an offline algorithm for the unit-fractions bin packing problem with at most H &plus; 1 bins. In the online setting, this article presents algorithms for both problems with H &plus; O(&sqrt;H) channels or bins, where the one for the unit-fractions bin packing problem is simpler. On the other hand, this article shows that already for the unit-fractions bin packing problem, any online algorithm must use at least H&plus;&Omega(ln H) bins. For instances in which the window sizes form a divisible sequence, an optimal online algorithm is presented. Finally, this article includes a new NP-hardness proof for the windows scheduling problem.
Multiscale analysis of fractal point processes and queues
Authors: W. M. Lam
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 03 (1996)

Using a powerful, recently-developed multiscale representation for fractal point processes, we characterize these processes under fundamental transformations which arise in a variety of important applications such as data network traffic modeling. Distribution results are obtained, including the inter-arrival density for a fractal point process subject to random erasure, the counting process distribution for the superposition of fractal point processes, and the steady-state customer distribution in queues with self-similar customer arrivals. Interpretations and implications of these results for applications are also discussed.
ORRP: Optimal Reactive Routing Protocol for Mobile Ad-Hoc Networks
Authors: Nabendu Chaki, Rituparna Chaki
Venue: Proceedings of the 6th International Conference on Computer Information Systems and Industrial Management Applications (2007)

An ad-hoc network is a self-supporting collection of mobile nodes that happen to exist within a close proximity in an interval of time. In this paper, a reactive routing protocol has been proposed that computes the shortest path in between any source-destination pair on demand. The approach, unlike other reactive protocols, finds a loop-free, optimal path between the end nodes. It does not use broadcasting like DSR or some other reactive protocols. In fact ORRP exchanges only (n-1) control packets, in the best case. A comparative performance evaluation establishes the advantages of ORRP. The paper is a substantial extension of our earlier work reported in [14].
Fast and accurate recognition of very-large-vocabulary continuous Mandarin speech for Chinese language with improved segmental probability modeling
Authors: Jia-Lin Shen
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 01 (1996)

This paper presents a fast and accurate recognition of continuous Mandarin speech with very large vocabulary using an improved segmental probability model (SPM) approach. In order to extensively utilize the acoustic and linguistic knowledge to further improve the recognition performance, a few special techniques are thus developed. Preliminary simulation results show that the final achievable rate for the base syllable recognition with the improved segmental probability modeling is as high as 91.62%, which indicates a 18.48% error rate reduction and more than 3 times faster than the well-studied sub-syllable-based CHMM. Also, a tone recognizer and a word-based Chinese language model are included and the achieved recognition accuracy for the final decoded Chinese characters is 92.10%.
Flash: an efficient and portable web server
Authors: Vivek S. Pai, Peter Druschel, Willy Zwaenepoel
Venue: Proceedings of the annual conference on USENIX Annual Technical Conference (1999)

This paper presents the design of a new Web server architecture called the asymmetric multi-process event-driven (AMPED) architecture, and evaluates the performance of an implementation of this architecture, the Flash Web server. The Flash Web server combines the high performance of single-process event-driven servers on cached workloads with the performance of multiprocess and multi-threaded servers on disk-bound workloads. Furthermore, the Flash Web server is easily portable since it achieves these results using facilities available in all modern operating systems. The performance of different Web server architectures is evaluated in the context of a single implementation in order to quantify the impact of a server's concurrency architecture on its performance. Furthermore, the performance of Flash is compared with two widely-used Web servers, Apache and Zeus. Results indicate that Flash can match or exceed the performance of existing Web servers by up to 50% across a wide range of real workloads. We also present results that show the contribution of various optimizations embedded in Flash.
Using Tk as remote GUI frontend for 4GL-database applications
Authors: Volker Schubert
Venue: Proceedings of the 5th conference on Annual Tcl/Tk Workshop 1997 - Volume 5 (1997)

This is a short report about our experience using Tk as GUI frontend. We wrote a compiler called F4GL, source compatible to the INFORMIX 4GL database language. (4GL means 4th generation language) This language was originally designed to create UNIX database applications with text-terminal output. 4GL programs compiled with F4GL generate Tcl-commands as graphic output (the text output is also still available). These Tcl-commands are sent over TCP/IP to a presentation server which will provide for conversation into graphic objects. We have presentation servers for X11 and Windows. 4GL Server is the presentation server for all Windows platforms and is implemented using Tcl/Tk. It is an Internet-Server like lpd or rshd whose services are available at a specific TCP port. We found different solutions for the network connection to the remote GUI / presentation server and had to solve various problems, which are discussed in detail in this poster. Writing a internet server in Tcl which evaluates Tcl-commands is very easy, but it introduces a security hole. The machine running 4GL Server is accessible from the internet with tcl-commands. That's why we implemented a special protocol to authenticate the users of the 4GL Server. We made some extensions, some of it appears to be useful for the whole Tcl-community. Until now we maintained our own Windows-port of Tk3.6, because the actual Windows-Tk4.x releases from Sun still have limitations, we will explain the reasons and show some performance bottlenecks (http://www.bj-ig.de/speed.html). In the near future we want to switch to official releases because the Tk4.xx and Tk8.xx versions offer many advantages, especially safe interpreters and the Tcl-Plugin. A good overview about the F4GL can be found at http://www.4js.com/f4gldoc.html, this is the webpage of 4JS, our trade-partner.
Assessment techniques for a learning-centered curriculum: evaluation design for Adventures in Supercomputing
Authors: B. Helland
Venue: Proceedings of the 26th Annual Frontiers in Education - Volume 01 (1996)

As the classroom paradigm shifts from being teacher-centered to being learner-centered, student assessments are evolving from paper-and-pencil testing to other methods of evaluation. Students should be probed for understanding, reasoning and critical thinking abilities rather than their ability to return memorized facts. The Department of Energy's pilot program, Adventures in Supercomputing (AiS), offers one example of assessment techniques developed for learner-centered curricula. The goals and objectives that are central to student learning in the AiS program involve the acquisition of thinking and problem-solving skills. School students are involved in a year-long computational science project. To complete the project, students employ the following tools: (1) the Internet to aid in researching their topics and communicating with their mentors, (2) computers to develop and test models of the problems, and (3) visualization software to understand their data. From these resources, students must pose hypotheses, devise methods for solutions, conduct appropriate simulations and draw proper conclusions. The assessment of the AiS program has employed a variety of methods to collect student data. THe methods of assessment used were traditional testing, performance testing, interviews, questionnaires via e-mail, and student presentations of projects. The data obtained have been analyzed by a professional assessment team. The results have been used to improve the AiS curriculum and establish the quality of the overall AiS program. This paper discusses the methods of assessment used and the results.
Beamforming and multiuser detection in CDMA systems with external interferences
Authors: O. Munoz
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 05 (1999)

Multiuser detection has been investigated to mitigate the near-far effect in CDMA systems. Antenna arrays have been shown to provide spatial diversity and cancel undesired signals. In this paper we consider the synergy of both multiuser detection and antenna arrays for the base station of a CDMA system. The receiver we proposed consists of the known multiuser decorrelator, which cancels multiple-access interferences followed by a beamformer for each user, which cancels the external interferences. This receiver adds an extra branch to the decorrelator. This additional branch, corresponding to a fictitious user with an unused code and zero power, allows to estimate the external interference signal subspace and compute a suitable beamforming weight-vector that cancels the external interferences. The receiver is also extended to the asynchronous case and all of this without any training signal or any a priori spatial information.
Interpretation of Probabilistic Algorithmic Logic in Nondeterministic Algorithmic Logic
Authors: Agnieszka Makarec
Venue: Proceedings of the 6th International Conference on Computer Information Systems and Industrial Management Applications (2007)

In this paper probabilistic and nondeterministic programs are considered on the ground of logic of programs. The formal semantics of probabilistic and nondeterministic computations of a program are the starting point for the comparing properties of these programs. We are interested in dependencies, especially in similarities between nondeterministic and probabilistic interpretation of a program.
Do students know best?: experiences of allowing students to become course designers
Authors: H. Whaley, S. Grice
Venue: ACM SIGCSE Bulletin (2007)

Computing departments are in an exclusive position to utilise students, as it is the nature of the subject area that ensures students have both the knowledge of the course material and the ability to develop resources for online environments. They have greater computer literacy levels than peers in other domains and can adapt the skills learnt through their curriculum to the context of online resource creation for education.