ppxscal/embedding_network huggingface dataset:
Asymptotics of Solutions of Periodic Problem for Generalized Nonlinear Hamiltonian System Singularly Perturbed by a Matrix
Authors: Galina A. Kurina
Venue: Journal of Dynamical and Control Systems (2008)

The paper deals with the periodic problem for a generalized nonlinear Hamiltonian system, which appears from the control optimality condition for the periodic problem of the minimization of the functional on trajectories of the equation with the operator A¿+¿¿B standing before the derivative, where the operator A is singular and A¿+¿¿B is invertible for sufficiently small ¿¿>¿0. Under some conditions, the asymptotic solution of such problem has been constructed in the form of the series with respect to nonnegative integer powers of ¿. The solvability of the considered problem has also been established for sufficiently small ¿¿>¿0.
Performance Analysis of Dynamic Spectrum Access Networks
Authors: Zhong Fan
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

In future dynamic spectrum access (DSA) wireless networks,secondary users can make use of spectrum opportunitiesdynamically for communications. These opportunitiesare available when primary users do not use theirlicensed spectrum slots. In this paper we study the scenario where spectrum opportunities are characterized bythe ON/OFF distribution. As a result, the queueing systemcan be analyzed using the well-established theory of fluidflow models and effective bandwidth. Based on a refinementto the original effective bandwidth approximation, wederive the packet loss probability for secondary users access to the available channels. Theoretical and numericalanalyses are used to investigate the impacts of various parameters of the underlying DSA link model on the systemperformance.
A new cylindrical element formulation and its application to structural analysis of laminated hollow cylinders
Authors: M. T. Ahmadian, M. Bonakdar
Venue: Finite Elements in Analysis and Design (2008)

Design and application of superelements in efficient prediction of the structural behavior in a short time has been one of the research interests in the last decade. Superelements are those elements which are capable of producing the same accurate result instead of several combined simple elements. In this paper a new 16-node cylindrical superelement is presented. Static and modal analyses of laminated hollow cylinders subjected to various kinds of loadings and boundary conditions are performed using this element. Some numerical examples are given to illustrate and validate the developed method. The accuracy of the results is evident from comparison of the findings with exact solution method and conventional finite element. It is seen that this element can predict the structural behavior of laminated cylinders in complex loading and boundary conditions in an efficient manner.
Solving spatial inverse problems using the probability perturbation method: An S-GEMS implementation
Authors: Ting Li, Jef Caers
Venue: Computers Geosciences (2008)

The probability perturbation method (PPM) is introduced as a flexible and efficient sampling technique for generating inverse solutions under a given prior geological constraint (prior model). In this paper, we present a methodology for producing software code that runs PPM within a public domain geostatistical software called the Stanford Geostatistical Earth Modeling Software (S-GEMS). The challenge in creating such code lies in the great diversity of forward models as well as prior models that can be handled by the PPM. Therefore, our software solution must be highly flexible and extensible such that it can be tailored to the various applications at hand. Our implementation has two main objectives: (1) to create an integrated working environment which provides users easy access to functionalities of the PPM through a general user interface as well as visualize results; (2) allow the users to plug-in their application specific code into the PPM algorithm workflow. We provide a two-part solution. The first part, which is hard-coded in S-GEMS as a plug-in module, runs the Dekker-Brent optimization algorithm to control the parameter perturbation needed for the inversion. It generates the PPM user interface and allows visualization of the spatial domain of interest using S-GEMS graphics capability. The second part is coded in object-oriented Python scripts and is used to control the PPM execution in S-GEMS. Users can program their particular needs in scripts and load them into S-GEMS as part of the PPM workflow. The same mechanism can be used to extend the capabilities of PPM itself by implementing new PPM variants in Python and making them a part of the base class hierarchy. Case studies are used to demonstrate the flexibility of our code. This approach requires the user to adapt only a small amount of python code, without modifying, or re-compiling the core S-GEMS code.
A declarative perspective on adaptive manet routing
Authors: Changbin Liu, Yun Mao, Mihai Oprea, Prithwish Basu, Boon Thau Loo
Venue: Proceedings of the ACM workshop on Programmable routers for extensible services of tomorrow (2008)

In this paper, we present a declarative perspective on adaptable extensible MANET protocols. Our work builds upon declarative networking, a recent innovation for building extensible network architectures using declarative languages. We make the following contributions. First, we demonstrate that traditional MANET protocols, ranging from proactive, reactive, to epidemic can be expressed in a compact fashion as declarative networks, and we validate experimentally the use of declarative techniques to implement traditional MANETs emulated on a testbed cluster. Second, we show that the declarative framework enables policy-driven adaptation, in which a generic set of declarative rule-based policies are used to make runtime decisions on the choice of MANET protocols. Third, we present some initial ideas on fine-grained protocol composition and adaptation, where a typical MANET protocol can be composed and adapted from simpler components.
A practical approach to robotic design for the DARPA Urban Challenge
Authors: Benjamin J. Patz, Yiannis Papelis, Remo Pillat, Gary Stein, Don Harper
Venue: Journal of Field Robotics (2008)

This article presents a practical approach to engineering a robot to effectively navigate in an urban environment. Inherent in this approach is the use of relatively simple sensors, actuators, and processors to generate robot vision, intelligence, and planning. Sensor data are fused from multiple low-cost, two-dimensional laser scanners with an innovative rotational mount to provide three-dimensional coverage with image processing using both range and intensity data. Information is combined with Doppler radar returns to yield a world view processed by a context-based reasoning control system to yield tactical mission commands forwarded to traditional proportional-integral-derivative (PID) control loops. As an example of simplicity and robustness, steering control successfully utilized a relatively simple follow-the-carrot guidance approach that has been successfully demonstrated at speeds of 60 mph (97 km-h). The approach yielded a robot that reached the finals of the Urban Challenge and completed approximately 2 h of the event before being forced to withdraw as a result of a global positioning system data failure. &copy; 2008 Wiley Periodicals, Inc.
On-Line Burst Header Scheduling in Optical Burst Switching Networks
Authors: Jian (Denny) Lin, Yuhua Chen, Albert M. K. Cheng
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

Optical burst switching (OBS) is a promising solution for allowing various-size data burst to be transported optically over Dense Wavelength Division Multiplexing (DWDM) without O/E/O (optical/electronic/optical) conversion. In OBS, networks, burst headers are sent ahead of the data bursts on a separate control channel to set up optical paths for the data bursts. While data bursts travel entirely in the optical domain, the burst headers have to be converted to electronic form and processed electronically. As the data channel bandwidth increases dramatically, the electronic control path for header processing is likely to become the performance bottleneck. It has been shown that control path overloading can severely degrade the performance of an OBS router. In this paper, we propose to formulate the burst header scheduling problem as an on-line time-constrained optimization problem for which we present a novel priority assignment method and a greedy on-line algorithm that consider both the urgency of the headers and the lengths of the bursts that the headers are representing. To the authors’ best knowledge, it is the first paper that targets on solving control channel’s overloading in OBS networks by improving the performance on throughput, as well as burst loss rate. Simulation results have shown that our technique is very effective.
Technical Communication: GUI for PC auto-shutdown
Authors: Mohd. Liakot Ali, Rafiqul Islam, A. Siti Anom, M. Y. Nurul Amziah
Venue: Computers and Electrical Engineering (2008)

Computer is a part and parcel of our daily life. It is being widely used at homes, offices, schools and industries. It is now an important issue to save user program and data as well as hardware and software of the personal computer (PC) itself from damage and corruption due to sudden power failure. This paper presents the solution of the problem. A graphical user interface (GUI) has been developed that monitors the status of the power supply of the PC. Whenever power goes out, it saves all the files that are opened and initiates auto-shutdown of the PC.
Efficient Video-Stream Filtering
Authors: Fabrizio Falchi, Claudio Gennaro, Pasquale Savino, Peter Stanchev
Venue: IEEE MultiMedia (2008)

A new approach for video-stream filtering that makes use of the features representing video content and exploits the properties of metric spaces can help reduce the filtering receiver's computational load.
The design of a low power carbon nanotube chemical sensor system
Authors: Taeg Sang Cho, Kyeong-jae Lee, Jing Kong, Anantha P. Chandrakasan
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

This paper presents a hybrid CNT/CMOS chemical sensor system that comprises of a carbon nanotube sensor array and a CMOS interface chip. The full system, including the sensor, consumes 32&mu;W at 1.83kS/s readout rate, accomplished through an extensive use of CAD tools and a model-based architecture optimization. A redundant use of CNT sensors in the frontend increases the reliability of the system.
The strong distance problem on the Cartesian product of graphs
Authors: Justie Su-Tzu Juan, Chun-Ming Huang, I-fan Sun
Venue: Information Processing Letters (2008)

Given a graph G and a strong oriented graph D=(V,F) of G. For u,v@?V(D), the strong distance sd(u,v) is the minimum size (the number of edges) of strong subdigraph of D containing u and v and the strong eccentricity se(u) is the maximum strong distance sd(u,v) for all v@?V(D). The strong radius and strong diameter of D are defined as the minimum and maximum strong eccentricities se(u) among all u@?V(D), respectively. The following four values: srad(G), SRAD(G), sdiam(G), and SDIAM(G) for a connected undirected graph G denote the minimum strong radius, maximum strong radius, minimum strong diameter, and maximum strong diameter, respectively, of D among all possible strong oriented graphs D of G. In this paper, we propose some important properties about these values and derive an inequality that gives an upper bound for each of srad(GxH) and sdiam(GxH) where G and H are any two graphs. Moreover, we can obtain srad(G) and sdiam(G) by substituting G into hypercube BC"n or two extension hypercubes EC"n and FC"n, respectively. For these graphs, we also give a lower bound of SDIAM(G) for each of them.
Surveillant Institutional Eyes in Korea: From Discipline to a Digital Grid of Control
Authors: Kwang-Suk Lee
Venue: The Information Society (2007)

This article investigates the shift from disciplinary societies (the visible and physical violence of power) to control societies (the modulating and normalizing techniques of power) in South Korea. At the institutional level, during the period of repressive and disciplinary society in Korea (1948-1992), the regulatory control systems of the state were mainly performed by two formidable apparatuses: the national ID system and the National Security Law. On the other hand, the deployment of institutional power since 1993 has been based on the logic of free-floating control, dispersion, normalization, and modulation. This study examines how the techniques of power were gradually transformed from a centralized and hierarchical model into a distributive and dispersed network model, based on flow, speed, and mobility.
Human expert modelling using semantics-oriented video retrieval for surveillance in hard industry
Authors: Pavel Praks, Jindřich Černohorský, Vojtěch Svátek
Venue: Proceedings of the 2nd international conference on Mobile multimedia communications (2006)

The surveillance application aims at improving the quality of technology via modelling human expert behaviour in the coking plant Mittal Steel Ostrava, the Czech Republic. Video data on several industrial processes are captured by means of a CCD camera and classified by using Latent Semantic Indexing (LSI) with the respect to etalons classified by an expert. We also investigate the possibility to combine LSI with color histogram analysis, using experience from our prior research on web image classification.
TSI finders for estimation of the location of an interference source using an ariborne array
Authors: Dan Madurasinghe, Andrew Shaw
Venue: EURASIP Journal on Advances in Signal Processing (2008)

An algorithm based on space fast time adaptive processing to estimate the physical location of an interference source closely associated with a physical object and enhancing the detection performance against that object using a phased array radar is presented. Conventional direction finding techniques can estimate all the signals and their associated multipaths usually in a single spectrum. However, none of the techniques are currently able to identify direct path (source direction of interest) and its associated multipath individually. Without this knowledge, we are not in a position to achieve an estimation of the physical location of the interference source via ray tracing. The identification of the physical location of an interference source has become an important issue for some radar applications. The proposed technique identifies all the terrain bounced interference paths associated with the source of interest only (main lobe interferer). This is achieved via the introduction of a postprocessor known as the terrain scattered interference (TSI) finder.
Two techniques for fast computation of constrained shortest paths
Authors: Shigang Chen, Meongchul Song, Sartaj Sahni
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

Computing constrained shortest paths is fundamental to some important network functions such as QoS routing, MPLS path selection, ATM circuit routing, and traffic engineering. The problem is to find the cheapest path that satisfies certain constraints. In particular, finding the cheapest delay-constrained path is critical for real-time data flows such as voice/video calls. Because it is NP-complete, much research has been designing heuristic algorithms that solve the ε-approximation of the problem with an adjustable accuracy. A common approach is to discretize (i.e., scale and round) the link delay or link cost, which transforms the original problem to a simpler one solvable in polynomial time. The efficiency of the algorithms directly relates to the magnitude of the errors introduced during discretization. In this paper, we propose two techniques that reduce the discretization errors, which allows faster algorithms to be designed. Reducing the overhead of computing constrained shortest paths is practically important for the successful design of a high-throughput QoS router, which is limited at both processing power and memory space. Our simulations show that the new algorithms reduce the execution time by an order of magnitude on power-law topologies with 1000 nodes. The reduction in memory space is similar.
Development of Telemedicine and Telecare over Wireless Sensor Network
Authors: Shuo-Jen Hsu, Hsin-Hsien Wu, Shih-Wei Chen, Tsang-Chi Liu, Wen-Tzeng Huang, Yuan-Jen Chang, Chin-Hsing Chen, You-Yin Chen
Venue: Proceedings of the 2008 International Conference on Multimedia and Ubiquitous Engineering (2008)

Telemedicine & Telecare aided by wireless sensor network (WSN) has recently become a health-caring trend in the future. However, the low data rate of WSN limited the acceptable quality of service. Researches [1-6] adopted ZigBee-based WSN to implement a platform and/or a telecare system. However, the capacity problem due to low data rate characteristic has not been addressed. Our research proposed an arrhythmia-aware telecare system and a new DSP-based WSN platform, enabling good digital signal processing performance in ZigBee-based WSN. Proved by simulations and several real tests, combination of the proposed platform and system can provide a more bandwidth-conserving and reliable telecare system, with lower wireless traffic jam and higher stability.
Microcantilever-based weather station for temperature, humidity and flow rate measurement
Authors: Rong-Hua Ma, Chia-Yen Lee, Yu-Hsiang Wang, Hao-Jen Chen
Venue: Microsystem Technologies (2008)

The current study develops a new process for the fabrication of Pt resistor temperature detectors (RTDs), cantilevers covered with a water-absorbent polyimide layer for humidity measurement and the bending-up of cantilevers to determine the flow rate. Pt RTDs are fabricated on the silicon substrate. The temperature measurement is based on the linear resistance variations when temperature changes. The polyimide layer is spun on the cantilever to form a humidity sensing layer. A variation in humidity causes moisture-dependent bending of the micro-cantilever, which changes the measured resistance of the resistor on the micro-cantilever. The same type of micro-cantilever, without spinning on polyimide, is used to form an anemometer. It is found that the cantilever bends slightly upward as a result of the released residual stress induced in the beam during the fabrication. When wind passes over the cantilever beam, a small deformation occurs. Variations in the flow rate can therefore be determined by measuring the changes in resistance caused by the beam deflection, using a LCR meter.
Matching algorithmic bounds for finding a Brouwer fixed point
Authors: Xi Chen, Xiaotie Deng
Venue: Journal of the ACM (JACM) (2008)

We prove a new discrete fixed point theorem for direction-preserving functions defined on integer points, based on a novel characterization of boundary conditions for the existence of fixed points. The theorem allows us to derive an improved algorithm for finding such a fixed point. We also develop a new lower bound proof technique. Together, they allow us to derive an asymptotic matching bound for the problem of finding a fixed point in a hypercube of any constantly bounded finite dimension. Exploring a linkage with the approximation version of the continuous fixed point problem, we obtain asymptotic matching bounds for the complexity of the approximate Brouwer fixed point problem in the continuous case for Lipschitz functions. It settles a fifteen-years-old open problem of Hirsch, Papadimitriou, and Vavasis by improving both the upper and lower bounds. Our characterization for the existence of a fixed point is also applicable to functions defined on nonconvex domains, which makes it a potentially useful tool for the design and analysis of algorithms for fixed points in general domains.
Experiments with a hybrid interior point/combinatorial approach for network flow problems
Authors: Antonio Frangioni, Claudio Gentile
Venue: Optimization Methods Software (2007)

Interior point (IP) algorithms for Min Cost Flow (MCF) problems have been shown to be competitive with combinatorial approaches, at least on some problem classes and for very large instances. This is in part due to availability of specialized crossover routines for MCF; these allow early termination of the IP approach, sparing it with the final iterations where the Karush Kuhn-Tucker (KKT) systems become more difficult to solve. As the crossover procedures are nothing but combinatorial approaches to MCF that are only allowed to perform few iterations, the IP algorithm can be seen as a complex 'multiple crash start' routine for the combinatorial ones. We report our experiments of allowing one primal-dual combinatorial algorithm to MCF to perform as many iterations as required to solve the problem after being warm-started by an IP approach. Our results show that the efficiency of the combined approach critically depends on the accurate selection of a set of parameters among very many possible ones, for which designing accurate guidelines appears not to be an easy task; however, they also show that the combined approach can be competitive with the original combinatorial algorithm, at least on some 'difficult' instances.
On bounded queries and approximation
Authors: R. Chang
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

This paper investigates the computational complexity of approximating NP-optimization problems using the number of queries to an NP oracle as a complexity measure. The results show a trade-off between the closeness of the approximation and the number of queries required. For an approximation factor k(n), loglog/sub k(n/) n queries to an NP oracle can be used to approximate the maximum clique size of a graph within a factor of k(n). However, this approximation cannot be achieved using fewer than loglog/sub k(n/) n-c queries to any oracle unless P=NP, where c is a constant that does not depend on k. These results hold when k(n) belongs to a class of functions which include any integer constant function, log n, log/sup a/ n and n/sup 1/a/. Similar results are obtained for graph coloring, set cover and other NP-optimization problems.
The truth about tech recycling: it's green or it's mean
Authors: Lynn Greiner
Venue: netWorker (2008)

The awkward thing about getting new tech toys is the fact that there's usually an old tech toy left over, suddenly unloved and unwanted. Over time drawers are filled with old cell phones and MP3 players, piles of old computers linger in our closets, or the obsolete electronics end up in the trash.
Fish-Bird: Cross-Disciplinary Collaboration
Authors: Mari Velonaki, David Rye, Steve Scheding, Stefan Williams
Venue: IEEE MultiMedia (2008)

At the Australian Centre for Field Robotics, media artist/researcher Mari Velonaki collaborated with roboticists, David Rye, Steve Scheding, and Stefan Williams to make the highly engaging new media work Fish-Bird. Through an iterative and carefully conceptualized process of art and science collaboration, the team worked at the cutting edge of both robotics and immersive interactive art.