ppxscal/embedding_network huggingface dataset:
Runtime optimization of vector operations on large scale SMP clusters
Authors: Costin Iancu, Steven Hofmeyr
Venue: Proceedings of the 17th international conference on Parallel architectures and compilation techniques (2008)

"Vector" style communication operations transfer multiple disjoint memory regions within one logical step. These operations are widely used in applications, they do improve application performance, and their behavior has been studied and optimized using different implementation techniques across a large variety of systems. In this paper we present a methodology for the selection of the best performing implementation of a vector operation from multiple alternative implementations. Our approach is designed to work for systems with wide SMP nodes where we believe that most published studies fail to correctly predict performance. Due to the emergence of multi-core processors we believe that techniques similar to ours will be incorporated for performance reasons in communication libraries or language runtimes. The methodology relies on the exploration of the application space and a classification of the regions within this space where a particular implementation method performs best. We use micro-benchmarks to measure the performance of an implementation for a given point in the application space and then compose profiles that compare the performance of two given implementations. These profiles capture an empirical upper bound for the performance degradation of a given protocol under heavy node load. At runtime, the application selects the implementation according to these performance profiles. Our approach provides performance portability and using our dynamic multi-protocol selection we have been able to improve the performance of a NAS Parallel Benchmarks workload by 22% on an IBM large scale cluster. Very positive results have also been obtained on large scale InfiniBand and Cray XT systems. This work indicates that perhaps the most important factor for application performance on wide SMP systems is the successful management of load on the Network Interface Cards.
Interlayer cooling potential in vertically integrated packages
Authors: T. Brunschwiler, B. Michel, H. Rothuizen, U. Kloter, B. Wunderle, H. Oppermann, H. Reichl
Venue: Microsystem Technologies (2008)

The heat-removal capability of area-interconnect-compatible interlayer cooling in vertically integrated, high-performance chip stacks was characterized with de-ionized water as coolant. Correlation-based predictions and computational fluid dynamic modeling of cross-flow heat-removal structures show that the coolant temperature increase due to sensible heat absorption limits the cooling performance at hydraulic diameters &#x2264;200&#x00a0;&#x03bc;m. An experimental investigation with uniform and double-side heat flux at Reynolds numbers &#x2264;1,000 and heat transfer areas of 1&#x00a0;cm2 was carried out to identify the most efficient interlayer heat-removal structure. The following structures were tested: parallel plate, microchannel, pin fin, and their combinations with pins using in-line and staggered configurations with round and drop-like shapes at pitches ranging from 50 to 200&#x00a0;&#x03bc;m and fluid structure heights of 100&#x2013;200&#x00a0;&#x03bc;m. A hydrodynamic flow regime transition responsible for a local junction temperature minimum was observed for pin fin in-line structures. The experimental data was extrapolated to predict maximal heat flux in chip stacks having a 4-cm2 heat transfer area. The performance of interlayer cooling strongly depends on this parameter, and drops from >200&#x00a0;W/cm2 at 1&#x00a0;cm2 and >50&#x00a0;&#x03bc;m interconnect pitch to <100&#x00a0;W/cm2 at 4&#x00a0;cm2. From experimental data, friction factor and Nusselt number correlations were derived for pin fin in-line and staggered structures.
Architecting Dependable Systems V, 1 edition
Authors: Rogrio de Lemos, Felicita Di Giandomenico, Cristina Gacek, Henry Muccini, Marlon Vieira
Venue: Lecture Notes In Computer Science (2008)

As software systems become ubiquitous, the issues of dependability become more and more crucial. Given that solutions to these issues must be considered from the very beginning of the design process, it is reasonable that dependability is addressed at the architectural level. This book was born of an effort to bring together the research communities of software architectures and dependability. This state-of-the-art survey contains expanded and peer-reviewed papers based on the carefully selected contributions to two workshops: the Workshop on Architecting Dependable Systems (WADS 2007), organized at the 2007 International Conference on Dependable Systems and Networks (DSN 2007), held in Edinburgh, UK in June 2007 and the Third Workshop on the Role of Software Architecture for Testing and Analysis (ROSATEA 2007) organized as part of a federated conference on Component-Based Software Engineering and Software Architecture (CompArch 2007), held in Medford, MA, USA in July 2007. It also contains a number of invited papers written by recognized experts in the area. The 14 papers are organized in topical sections on critical infrastructures, rigorous design/fault tolerance, and verification and validation.
Discovery of convoys in trajectory databases
Authors: Hoyoung Jeung, Man Lung Yiu, Xiaofang Zhou, Christian S. Jensen, Heng Tao Shen
Venue: Proceedings of the VLDB Endowment (2008)

As mobile devices with positioning capabilities continue to proliferate, data management for so-called trajectory databases that capture the historical movements of populations of moving objects becomes important. This paper considers the querying of such databases for convoys, a convoy being a group of objects that have traveled together for some time. More specifically, this paper formalizes the concept of a convoy query using density-based notions, in order to capture groups of arbitrary extents and shapes. Convoy discovery is relevant for real-life applications in throughput planning of trucks and carpooling of vehicles. Although there has been extensive research on trajectories in the literature, none of this can be applied to retrieve correctly exact convoy result sets. Motivated by this, we develop three efficient algorithms for convoy discovery that adopt the well-known filter-refinement framework. In the filter step, we apply line-simplification techniques on the trajectories and establish distance bounds between the simplified trajectories. This permits efficient convoy discovery over the simplified trajectories without missing any actual convoys. In the refinement step, the candidate convoys are further processed to obtain the actual convoys. Our comprehensive empirical study offers insight into the properties of the paper's proposals and demonstrates that the proposals are effective and efficient on real-world trajectory data.
Regularized least squares fuzzy support vector regression for financial time series forecasting
Authors: Reshma Khemchandani, Jayadeva, Suresh Chandra
Venue: Expert Systems with Applications: An International Journal (2009)

In this paper, we propose a novel approach, termed as regularized least squares fuzzy support vector regression, to handle financial time series forecasting. Two key problems in financial time series forecasting are noise and non-stationarity. Here, we assign a higher membership value to data samples that contain more relevant information, where relevance is related to recency in time. The approach requires only a single matrix inversion. For the linear case, the matrix order depends only on the dimension in which the data samples lie, and is independent of the number of samples. The efficacy of the proposed algorithm is demonstrated on financial datasets available in the public domain.
A method for estimating transformer temperatures and elapsed lives considering operation loads
Authors: Chun-Yao Lee, Hong-Chan Chang, Hung-Cheng Chen
Venue: WSEAS TRANSACTIONS on SYSTEMS (2008)

A simplified temperature model is presented to substitute for the traditional temperature measurement. First, the temperature model of a transformer, based on IEEE std. C57.91, is briefly reviewed and then a load assumption is proposed to simplify the temperature formula. Second, a test case from the appendix of IEEE C57.91 is used to indicate that the measured and calculated temperatures are nearly the same using the proposed method. Finally, error analysis illustrates that the simplified models can be an alternative way to calculate the transformer temperatures and the transformer elapsed life.
Augmented & Virtual Reality applications in&#x00a0;the&#x00a0;field of&#x00a0;logistics
Authors: Rupert Reif, Dennis Walch
Venue: The Visual Computer: International Journal of Computer Graphics (2008)

Changing basic conditions in the field of logistics requires intuitive planning methods as well as new ways of supporting and educating the operative staff. VR and AR show a great promise for that.
Combined Effects of Frequency Quantization and Additive Input Noise in a First-order Digital PLL
Authors: Cillian Ó Tuama, James P. Gleeson
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

A recent work by Gardner [Gardner, F.M., Frequency granularity in digital phase-locked loops, IEEE Trans. Commun., 44 (1996), 749758] on the subject of digital phase-locked loops (DPLLs) investigated, via simulation, the characteristics of the phase-jitter caused by frequency quantization in the numerically-controlled oscillator. Further works by Feely, Teplinsky et al [Feely, O., Rogers, A., and Teplinsky, A., Phase-jitter dynamics of digital phaselocked loops, IEEE Trans. Circuits and Systems, Part I: Fundamental Theory and Applications, 46 (1999), 545-558], [Feely, O., and Teplinsky, A., Phase-jitter dynamics of digital phase-locked loops: Part II, IEEE Trans. Circuits and Systems, Part I: Fundamental Theory and Applications., 47 (2000), 458-473] used the theory of nonlinear dynamics to provide a complete analytical explanation of this phase-jitter. This paper examines in detail the case where the input signal is embedded in additive noise, a scenario earlier investigated by Gardner where no satisfactory method of characterising the phase-jitter was found. Here, further numerical results for the 1-D DPLL are presented and it is shown analytically how the DPLL noise-jitter dynamics may be approximated by a noisy circle rotation map for reasonable levels of additive noise. The noise in this case is unique and highly nonlinear in nature and thus not amenable to traditional analysis. By considering the the probability flow over time, a time-dependent difference-delay equation is derived for the probability density function (PDF) of the phase-jitter. It is shown that this PDF reaches a steady-state and that this state is described by a non-local equation. The solutions of this equation are investigated, both numerically and analytically, and used to explain the interaction between the additive and quantization noise that was previously not understood.
ENNA: software effort estimation using ensemble of neural networks with associative memory
Authors: Yigit Kultur, Burak Turhan, Ayse Basar Bener
Venue: Proceedings of the 16th ACM SIGSOFT International Symposium on Foundations of software engineering (2008)

Companies usually have limited amount of data for effort estimation. Machine learning methods have been preferred over parametric models due to their flexibility to calibrate the model for the available data. On the other hand, as machine learning methods become more complex they need more data to learn from. Therefore the challenge is to increase the performance of the algorithm when there is limited data. In this research we used a relatively complex machine learning algorithm, neural networks, and showed that stable and accurate estimations are achievable with an ensemble using associative memory. Our experimental results revealed that our proposed algorithm (ENNA) achieves on the average PRED(25) = 36.4 which is a significant increase compared to Neural Network (NN) PRED(25) = 8.
Particle Swarm Optimization Based Clustering of Web Usage Data
Authors: Shafiq Alam, Gillian Dobbie, Patricia Riddle
Venue: Proceedings of the 2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology - Volume 03 (2008)

Web session clustering is one of the important web usage mining techniques which aims to group usage sessions on the basis of some similarity measures. In this paper we describe a new web session clustering algorithm that uses particle swarm optimization. We review the existing web usage clustering techniques and propose a swarm intelligence based PSO-clustering algorithm for the clustering of web user sessions. The proposed algorithm works independently without hybridization with any other clustering algorithm. The results show that our approach performs better than the benchmark K-means clustering algorithm for clustering web usage sessions.
Formation of algal bloom in the northern Arabian Sea deep waters during January-March: a study using pooled in situ and satellite data
Authors: R. M. Dwivedi, M. Raman, K. N. Babu, S. K. Singh, N. K. Vyas, S. G. P. Matondkar
Venue: International Journal of Remote Sensing (2008)

The formation of winter bloom (January-March) was studied in deep waters of the northeastern Arabian Sea (NAS) during 2003 and 2004. Six ship cruises were undertaken at different phases of the bloom to examine its formation. Along with physical and biological observations, optical parameters including profiles of upwelling and downwelling irradiance were collected using a Satlantic underwater radiometer and photosynthetically active radiation (PAR) was calculated using prosoft software. Satellite data sets for chlorophyll concentration, aerosol optical depth (AOD), PAR from the Oceansat-I Ocean Colour Monitor (OCM), and sea winds vectors from the QuikSCAT scatterometer were also used to study the winter algal bloom formation. This study attempts to explain the probable mechanisms that activate the bloom and its dynamics, particularly those due to the influence of wind. The study also presents an intercomparison of relevant parameters during different phases of the event, from the late winter to early spring intermonsoon season. The causes of winter bloom reported by other investigators have been verified with the use of satellite data. An additional observation was attempted that strengthened the explanation of convective mixing and resulting intensification of the bloom. The higher wind speed in February-March 2003 compared to that in 2004 caused a higher aerosol concentration in the overlying atmosphere, thus leading to reduced shortwave solar radiation and PAR over the surface in 2003. This caused a cooling effect in the NAS deep waters. This cooling is thought to be supplementary to the already reported winter cooling, and to cooling due to evaporation. As a result, a substantial increase in surface seawater density was observed, consequently enhancing convective action due to densification and nutrient concentration. The result is that the bloom was homogeneous in space and had a larger concentration during March 2003 than March 2004.
Running applications efficiently in online social networks
Authors: Roger Curry, Cameron Kiddle, Nayden Markatchev, Rob Simmonds, Tingxi Tan, Martin Arlitt, Bruce Walker
Venue: ACM SIGMETRICS Performance Evaluation Review (2008)

In the past several years, online social networks (OSNs) such as Facebook and MySpace have become extremely popular with Internet users. Such sites are popular with users because they simplify both communication among "communities" and access to applications. Application developers are attracted to these sites also, as they are able to exploit "word-of-mouth" marketing, which these OSN sites have embodied into their user experience. A challenge for developers though is managing the application, as it is difficult to predict how successful the marketing will be. Our solution combines an OSN, Virtual Appliances, and a utility computing environment together. We demonstrate our solution using the Facebook portal (OSN), the Fire Dynamics Simulator (application), and a utility environment we built using tools such as Condor, Moab and Xen. The application is supported using Virtual Appliances, which interact with our flexible infrastructure to dynamically expand and contract based on user demand. Thus, we are able to make much more efficient use of the underlying physical infrastructure. We believe that our solution also has great potential for enterprise IT environments. Initial feedback suggests combining an OSN with our flexible infrastructure provides a much better user experience than the traditional, standalone use of the (legacy) application, and simplifies the management and increases the effective utilization of the underlying IT resources.
IP models for round robin tournaments
Authors: Dirk Briskorn, Andreas Drexl
Venue: Computers and Operations Research (2009)

Generally speaking in sports competition a number of teams play against each other over a period of time according to a certain scheme. The round robin scheme is very popular in many team sports like soccer and basketball. In this paper we study several basic variants of round robin tournaments. Additionally, we examine real world issues that have to be considered when constructing a sports league schedule. We consider constraints imposed by third parties such as security aspects and legal requirements. Moreover, we analyze constraints aiming at attractive and fair sports league schedules. Throughout this paper integer programming models are the means to formally define what the particular problem under consideration is all about. Moreover, the standard solver Cplex is used in order to compute optimal solutions for small- to medium-size instances. Computational results indicate which particular constraint to relax in order to come up with acceptable schedules in reasonable time.
Scalable ad-hoc entity extraction from text collections
Authors: Sanjay Agrawal, Kaushik Chakrabarti, Surajit Chaudhuri, Venkatesh Ganti
Venue: Proceedings of the VLDB Endowment (2008)

Supporting entity extraction from large document collections is important for enabling a variety of important data analysis tasks. In this paper, we introduce the "ad-hoc" entity extraction task where entities of interest are constrained to be from a list of entities that is specific to the task. In such scenarios, traditional entity extraction techniques that process all the documents for each ad-hoc entity extraction task can be significantly expensive. In this paper, we propose an efficient approach that leverages the inverted index on the documents to identify the subset of documents relevant to the task and processes only those documents. We demonstrate the efficiency of our techniques on real datasets.
GPU evolution: will graphics morph into compute?
Authors: Norm Rubin
Venue: Proceedings of the 17th international conference on Parallel architectures and compilation techniques (2008)

In the last several years GPU devices have started to evolve into supercomputers. New, non-graphics, features are rapidly appearing along with new more general programming languages. One reason for the quick pace of change is that, games and hardware evolve together: Hardware vendors review the most popular games, looking for places to add hardware while game developers review new hardware, looking for places to add more realism. Today, we see both GPU devices and games moving from a model of looks real to one of acts real. One consequence of acts real is that evaluating physics, simulations, and artificial intelligence on a GPU is becoming an element of future game programs. We will review the difference between a CPU and a GPU. Then we will describe hardware changes added to the current generation of AMD graphics processors, including the introduction of traditional compute operations such as double precision, scatter/gather and local memory. Along with new features, we have added new metrics like performance/watt and performance/dollar. The current AMD GPU processor delivers 9 gigaflops/watt and 5 gigaflops/dollar. For the last two generations, each AMD GPU has provided double the performance/watt of the prior machine. We believe the software community needs to become more aware and appreciate these metrics. Because this has been a kind of co-evolution and not a process of radical change, current GPU devices have retained a number of odd sounding transitional features, including fixed functions like memory systems that can do filtering, depth buffers, a rasterizer and the like. Today, each of these remain because they are important for graphics performance. Software on GPU devices also shows transitional features. As AI/physics virtual reality starts to become important, development frameworks have started to shift. Graphics APIs have added compute shaders. Finally, there has been a set of transitional programs implemented by graphics programmers but whose only real connection with graphics is that the result is rendered. One early example is toy shop which contains a weak physical simulation of rain on window (it looks great but the random number generator would not pass any kind of test). A more recent and better acting program is March of the Froblins an AI program related to robotic path calculations. This program both simulates large crowds of independent creatures and shows how massively parallel compute can benefit character-centric entertainment.
Resource efficient logical topology design for IP-over-WDM backbone networks
Authors: Phuong Nga Tran, Ulrich Killat
Venue: Computer Communications (2008)

With the advancements in WDM technology to provide huge capacity and the Internet Protocol playing a dominant role in networking technology, IP-over-WDM network becomes a potential candidate for next generation networks. This article studies the problem of designing logical topologies for IP-over-WDM backbone networks. One important feature of IP-over-WDM networks is the reconfigurability when traffic demands change over time. If the network resource is not used efficiently, the reconfiguration can cause network disruption because no new wavelength channels (lightpaths) can be added before deleting some working channels. Moreover, more than one logical topology for different services or from different ISPs can be simultaneously implemented in an existing WDM network. Hence using resources efficiently is an important issue while designing logical topologies. In this article, we present a new approach to design logical topologies so that the network resource is used most efficiently while the network performance is guaranteed. The problem is formulated as an MILP problem. Since this MILP problem is NP-hard and can be applied for small networks only, a heuristic algorithm based on iterative optimization is proposed to solve the problem for real-size networks.
Shape-topology optimization for Navier-Stokes problem using variational level set method
Authors: Xian-Bao Duan, Yi-Chen Ma, Rui Zhang
Venue: Journal of Computational and Applied Mathematics (2008)

We consider the shape-topology optimization of the Navier-Stokes problem. A new algorithm is proposed based on the variational level set method. By this algorithm, a relatively smooth evolution can be maintained without re-initialization and drastic topology change can be handled easily. Finally, the promising features of the proposed method are illustrated by two benchmark examples.