ppxscal/embedding_network huggingface dataset:
Biophysical modelling and NDVI time series to project near-term forage supply: spectral analysis aided by wavelet denoising and ARIMA modelling
Authors: M. N. Alhamad, J. Stuth, M. Vannucci
Venue: International Journal of Remote Sensing (2007)

Point-based biophysical simulation of forage production coupled with 1-km AVHRR NDVI data was used to determine the feasibility of projecting forage conditions 84 days into the future to support stocking decision making for livestock production using autoregressive integrated moving average (ARIMA) with Box and Jenkins methodology. The study was conducted at three highly contrasting ecosystems in South Texas over the period 1989-2000. Wavelet transform was introduced as a mathematical tool to denoise the NDVI time series. The simulated forage production, NDVI and denoised NDVI (DeNDVI) were subject to spectral decomposition for the detection of periodicities. Spectral analysis revealed bimodal vegetation growth patterns in Southwestern Texas. A yearly cycle (364 days) of peak vegetation production was detected for the three study sites, another peak forage production was revealed by spectral analysis at 182 days following the first peak in vegetation production. A similar trend was found for the NDVI imageries sensing the study sites. Wavelet denoising of NDVI signal was effective in revealing clear periodicities in one study site where maximum variability of NDVI was noted. The Box and Jenkins ARIMA modelling approach was used as a forecasting method for near-term forage production to assist range managers in proactive operational stocking decisions to mitigate drought risk. Using denoised NDVI provided forage projections with the lowest standard error prediction (SEP) throughout the forecast 84-day periods. However, acceptable SEP was only achieved up to 6 weeks into a projection for the forage-only based forecasts. The ARIMA forecasting methodology appears to offer a new approach to help managers of livestock production through the creation of near real-time early warning systems. Using satellite-derived NDVI data as a covariate improved the forecast quality and reduced the standard error of forecast in three highly contrasting sites. Denoising the NDVI data using wavelet methods further improved the forecast quality in all study sites. The integration of AVHRR NDVI data and biophysical simulation of forage production appears a promising approach for assisting decision makers in a positive manner by assessing forage conditions in response to emerging weather conditions and near real-time projection of available forage for grazing animals.
Explicit Volume-Preserving Splitting Methods for Linear and Quadratic Divergence-Free Vector Fields
Authors: R. I. McLachlan, H. Z. Munthe-Kaas, G. R. W. Quispel, A. Zanna
Venue: Foundations of Computational Mathematics (2008)

We present new explicit volume-preserving methods based on splitting for polynomial divergence-free vector fields. The methods can be divided in two classes: methods that distinguish between the diagonal part and the off-diagonal part and methods that do not. For the methods in the first class it is possible to combine different treatments of the diagonal and off-diagonal parts, giving rise to a number of possible combinations.
Computability Theoretic Properties of the Entropy of Gap Shifts
Authors: Peter Hertling, Christoph Spandl
Venue: Fundamenta Informaticae (2008)

First, we analyse the computability theoretic relationship between the defining set S of a "gap shift" and the language of the gap shift. Therefore, we look at various computability theoretic conditions that the set S of a gap shift or the language of a gap shift might satisfy: decidability, computable enumerability, and computable enumerability of the complement. Then we look at the topological entropy of a gap shift and analyse the relationship between on the one hand the various kinds of computability theoretic conditions on a gap shift that we just mentioned and on the other hand various kinds of computability theoretic conditions on the entropy resp. on any real number in the unit interval: computability, left-computability, and right-computability.
Tagging semantics: investigations with wordnet
Authors: Michael J. Cole, Jacek Gwizdka
Venue: Proceedings of the 8th ACM/IEEE-CS joint conference on Digital libraries (2008)

The content of a tag sequence references both a user's concepts and the user's conceptualization of an information object. The tagging history of 823 users of the Delicious social tagging service is analyzed using WordNet. Three semantic measures of the tagging content are developed: the level of category references, the changes in category level for each noun as the tagging sequence unfolds, and the scope of concept coverage as the compactness of the WordNet subgraph for the noun senses. Observed patterns of concept reference as a function of sequence position hint at dynamic properties of the tag production process by marking a trace of cognitive activity. If tagging is object categorization, these measures provide a view of the personal categorization behavior of non-professionals and illuminate biases in the production of 'folksonomies' due to tag production processes.
Automatic volume management for programmable microfluidics
Authors: Ahmed M. Amin, Mithuna Thottethodi, T. N. Vijaykumar, Steven Wereley, Stephen C. Jacobson
Venue: Proceedings of the 2008 ACM SIGPLAN conference on Programming language design and implementation (2008)

Microfluidics has enabled lab-on-a-chip technology to miniaturize and integrate biological and chemical analyses to a single chip comprising channels, valves, mixers, heaters, separators, and sensors. Recent papers have proposed programmable labs-on-a-chip as an alternative to traditional application-specific chips to reduce design effort, time, and cost. While these previous papers provide the basic support for programmability, this paper identifies and addresses a practical issue, namely, fluid volume management. Volume management addresses the problem that the use of a fluid depletes it and unless the given volume of a fluid is distributed carefully among all its uses, execution may run out of the fluid before all its uses are complete. Additionally, fluid volumes should not overflow (i.e., exceed hardware capacity) or underflow (i.e., fall below hardware resolution). We show that the problem can be formulated as a linear programming problem (LP). Because LP's complexity and slow execution times in practice may be a concern, we propose another approach, called DAGSolve, which over-constrains the problem to achieve linear complexity while maintaining good solution quality. We also propose two optimizations, called cascading and static replication, to handle cases involving extreme mix ratios and numerous fluid uses which may defeat both LP and DAGSolve. Using some real-world assays, we show that our techniques produce good solutions while being faster than LP.
Fuzzy semi-parametric sample selection model for participation of married women
Authors: L. Muhamad Safiih, A. A. Basah Kamil, M. T. Abu Osman
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

The sample selection model is studied in the context of semi-parametric methods. The issue of uncertainty and ambiguity are still major problems and the modelling of a semi-parametric sample selection model as well as its parametric is complicated. The best approach of accounting for uncertainty and ambiguity is to take advantage of the tools provided by the theory of fuzzy sets. The semi-parametric of a sample selection model is an econometric model that has found an interesting application in empirical studies. In this paper, the married women participants in the Malaysia labour force are studied. It comprises the analysis of a) participation equation in the wage sector and b) the wage equation in the wage sector. The data set used for this study is from the Malaysian population and family survey 1994 (MPFS-1994).
Effective Symbolic Dynamics
Authors: Douglas Cenzer, S. Ali Dashti, Jonathan L. F. King
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

We investigate computable subshifts and the connection with effective symbolic dynamics. It is shown that a decidable @P"1^0 class P is a subshift if and only if there is a computable function F mapping 2^N to 2^N such that P is the set of itineraries of elements of 2^N. A @P"1^0 subshift is constructed which has no computable element. We also consider the symbolic dynamics of maps on the unit interval.
Hit Miss Networks with Applications to Instance Selection
Authors: Elena Marchiori
Venue: The Journal of Machine Learning Research (2008)

In supervised learning, a training set consisting of labeled instances is used by a learning algorithm for generating a model (classifier) that is subsequently employed for deciding the class label of new instances (for generalization). Characteristics of the training set, such as presence of noisy instances and size, influence the learning algorithm and affect generalization performance. This paper introduces a new network-based representation of a training set, called hit miss network (HMN), which provides a compact description of the nearest neighbor relation over pairs of instances from each pair of classes. We show that structural properties of HMN's correspond to properties of training points related to the one nearest neighbor (1-NN) decision rule, such as being border or central point. This motivates us to use HMN's for improving the performance of a 1-NN, classifier by removing instances from the training set (instance selection). We introduce three new HMN-based algorithms for instance selection. HMN-C, which removes instances without affecting accuracy of 1-NN on the original training set, HMN-E, based on a more aggressive storage reduction, and HMN-EI, which applies iteratively HMN-E. Their performance is assessed on 22 data sets with different characteristics, such as input dimension, cardinality, class balance, number of classes, noise content, and presence of redundant variables. Results of experiments on these data sets show that accuracy of 1-NN classifier increases significantly when HMN-EI is applied. Comparison with state-of-the-art editing algorithms for instance selection on these data sets indicates best generalization performance of HMN-EI and no significant difference in storage requirements. In general, these results indicate that HMN's provide a powerful graph-based representation of a training set, which can be successfully applied for performing noise and redundance reduction in instance-based learning.
The design navigator: charting java programs
Authors: Epameinondas Gasparis, Amnon H. Eden, Jonathan Nicholson, Rick Kazman
Venue: Companion of the 30th international conference on Software engineering (2008)

The Design Navigator is a semi-automated design mining tool which reverse engineers LePUS3 design charts from Java™ 1.4 programs at any level of abstraction in reasonable time. We demonstrate the Design Navigator's step-wise charting process of Java Foundation Classes, generating decreasingly abstract charts of java.awt and discovering building-blocks in its design.
IP=PSPACE (interactive proof=polynomial space)
Authors: A. Shamir
Venue: Proceedings of the 31st Annual Symposium on Foundations of Computer Science (1990)

It is proved that, when both randomization and interaction are allowed, the proofs that can be verified in polynomial time are exactly those proofs that can be generated with polynomial space. The interactive proofs introduced use only public coins, are accepted with probability one when the prover is honest, require only logarithmic workspace when the verifier is given a two-way access to his or her random tape, and by the use of known techniques can be turned into zero-knowledge proofs under the sole assumption that one-way functions exist.
IUI4DR: intelligent user interfaces for developing regions
Authors: Sheetal K Agarwal, Nitendra Rajput, John Canny, Apala Lahiri Chavan
Venue: Proceedings of the 13th international conference on Intelligent user interfaces (2008)

Information Technology has had significant impact on the society and has touched all aspects of our lives. So far, computers and expensive devices have fueled this growth. The challenge now is to take this success of IT to its next level where IT services can be accessed by masses. "Masses" here mean the people who (a) are not yet IT literate and/or (b) do not have the purchase power to use the current IT delivery mechanisms (PC centric model) and/or (c) do not find current IT solutions and services relevant to their life or business. Interestingly, a huge portion of the world's population falls in this category. To enable the IT access to such masses, this workshop focuses on easy-to-use and affordable, yet powerful, user interfaces that can be used by this population.
A UNIFIED APPROACH TO GRAPHEME-TO-PHONEME CONVERSION FOR THE PLATTOS SLOVENIAN TEXT-TO-SPEECH SYSTEM
Authors: Matej Rojc, Zdravko Kacic
Venue: Applied Artificial Intelligence (2007)

This article presents a new unified approach to modeling grapheme-to-phoneme conversion for the PLATTOS Slovenian text-to-speech system. A cascaded structure consisting of several successive processing steps is proposed for the aim of grapheme-to-phoneme conversion. Processing foreign words and rules for the post-processing of phonetic transcriptions are also incorporated in the engine. The grapheme-to-phoneme conversion engine is flexible, efficient, and appropriate for multilingual text-to-speech systems. The grapheme-to-phoneme conversion process is described via finite-state machine formalism. The engine developed for Slovenian language can be integrated into various applications but can be even more efficiently integrated into architectures based on finite-state machine formalisms. Provided the necessary language resources are available, the presented approach can also be used for other languages.
On the performance benefits of multihoming route control
Authors: Aditya Akella, Bruce Maggs, Srinivasan Seshan, Anees Shaikh
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

Multihoming is increasingly being employed by large enterprises and data centers to extract good performance and reliability from their ISP connections. Multihomed end networks today can employ a variety of route control products to optimize their Internet access performance and reliability. However, little is known about the tangible benefits that such products can offer, the mechanisms they employ and their trade-offs. This paper makes two important contributions. First, we present a study of the potential improvements in Internet round-trip times (RTTs) and transfer speeds from employing multihoming route control. Our analysis shows that multihoming to three or more ISPs and cleverly scheduling traffic across the ISPs can improve Internet RTTs and throughputs by up to 25% and 20%, respectively. However, a careful selection of ISPs is important to realize the performance improvements. Second, focusing on large enterprises, we propose and evaluate a wide-range of route control mechanisms and evaluate their design trade-offs. We implement the proposed schemes on a Linux-based Web proxy and perform a trace-based evaluation of their performance. We show that both passive and active measurement-based techniques are equally effective and could improve the Web response times of enterprise networks by up to 25% on average, compared to using a single ISP. We also outline several "best common practices" for the design of route control products.
Cooperative multibeamforming in ad hoc networks
Authors: Chuxiang Li, Xiaodong Wang
Venue: EURASIP Journal on Advances in Signal Processing (2008)

We treat the problem of cooperative multiple beamforming in wireless ad hoc networks. The basic scenario is that a cluster of source nodes cooperatively forms multiple data-carrying beams toward multiple destination nodes. To resolve the hidden node problem, we impose a link constraint on the receive power at each unintended destination node. Then the problem becomes to optimize the transmit powers and beam weights at the source cluster subject to the maximal transmit power constraint, the minimal receive signal-to-interference-plus-noise ratio (SINR) constraints at the destination nodes, and the minimal receive power constraints at the unintended destination nodes. We first propose an iterative transmit power allocation algorithm under fixed beamformers subject to the maximal transmit power constraint, as well as the minimal receive SINR and receive power constraints. We then develop a joint optimization algorithm to iteratively optimize the powers and the beamformers based on the duality analysis. Since channel state information (CSI) is required by the sources to perform the above optimization, we further propose a cooperative scheme to implement a simple CSI estimation and feedback mechanism based on the subspace tracking principle. Simulation results are provided to demonstrate the performance of the proposed algorithms.
Algorithm 881: A Set of Flexible GMRES Routines for Real and Complex Arithmetics on High-Performance Computers
Authors: Valérie Frayssé, Luc Giraud, Serge Gratton
Venue: ACM Transactions on Mathematical Software (TOMS) (2008)

In this article we describe our implementations of the FGMRES algorithm for both real and complex, single and double precision arithmetics suitable for serial, shared-memory, and distributed-memory computers. For the sake of portability, simplicity, flexibility, and efficiency, the FGMRES solvers have been implemented in Fortran 77 using the reverse communication mechanism for the matrix-vector product, the preconditioning, and the dot-product computations. For distributed-memory computation, several orthogonalization procedures have been implemented to reduce the cost of the dot-product calculation, which is a well-known bottleneck of efficiency for Krylov methods. Furthermore, either implicit or explicit calculation of the residual at restart is possible depending on the actual cost of the matrix-vector product. Finally, the implemented stopping criterion is based on a normwise backward error.
Isn't it time you had an emulab?
Authors: W. David Laverell, Zongming Fei, James N. Griffioen
Venue: ACM SIGCSE Bulletin (2008)

Emulabs, network testbeds on which experiments can be carried out through a web interface, are widely recognized as useful research environments. We believe that Emulabs are also excellent platforms for teaching courses in operating systems and networking. Moreover, equipment costs have fallen, and Emulab software has evolved, to the point where any school could conceivably afford their own. This raises the obvious question: "Should institutions build and operate their own Emulab?". To get a handle on this question, we describe our experiences building and operating Edulabs--Emulabs specifically designed for education--at Calvin College and the University of Kentucky. We argue that with the right technical support, owning and operating one's own Emulab is a worthwhile endeavor that has many benefits. We acknowledge, however, that in the absence of good technical support, deploying one's own Emulab can be a difficult enterprise. We also describe how we enhanced Emulab to improve its utility in an educational setting.
Towards odyssey-VCS 2: improvements over a UML-based version control system
Authors: Leonardo Murta, Chessman Corrêa, João Gustavo Prudêncio, Cláudia Werner
Venue: Proceedings of the 2008 international workshop on Comparison and versioning of software models (2008)

Models are becoming first class artifacts in Software Engineering. Due to that, an infrastructure is needed to support model evolution in the same way we have for source-code. One of the key elements of such infrastructure is a version control system properly designed for models. In previous work, we presented Odyssey-VCS, a version control system tailored to fine-grained UML model elements. In this paper, we discuss the main improvements that we are incorporating on the second release of this system, which are: support for UML 2, reflective processing, explicit branching and auto-branching, generic merge algorithm, support for pessimistic concurrency policy, and support for hooks.
Classification of Elbow Electormyography Signals based on Directed Transfer Functions
Authors: Rhonira Latif, Saeid Sanei, Kianoush Nazarpour
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 02 (2008)

A new approach for classification of electromyography (EMG) of the flexion and extension signals is introduced here. Multivariate Autoregressive (MVAR) model has been applied to a two-channel set of EMG signals from the biceps and triceps muscles during flexion and extension positions of the elbow. The MVAR coefficients are then used to define the Directed Transfer Function (DTF), which estimates the strength of the direction of the signals flow between the channels. The maximum strength of the DTF was used as the frequency domain features (training data) for EMG classification via support vector machine (SVM) algorithm. As the features obtained from the experiment uniquely describe the flexion and extension, the classifier becomes linear which lead to low level of misclassification. The overall method described here has a potential to detect and classify the type and level of muscular disorder from the way the muscle signals interact with each other.
Experiences with open overlays: a middleware approach to network heterogeneity
Authors: Paul Grace, Danny Hughes, Barry Porter, Gordon S. Blair, Geoff Coulson, Francois Taiani
Venue: Proceedings of the 3rd ACM SIGOPS/EuroSys European Conference on Computer Systems 2008 (2008)

In order to provide an increasing number of functionalities and benefit from sophisticated and application-tailored services from the network, distributed applications are led to integrate an ever-widening range of networking technologies. As these applications become more complex, this requirement for 'network heterogeneity' is becoming a crucial issue in their development. Although progress has been made in the networking community in addressing such needs through the development of network overlays, we claim in this paper that the middleware community has been slow to integrate these advances into middleware architectures, and, hence, to provide the foundational bedrock for heterogeneous distributed applications. In response, we propose our 'open overlays' framework. This framework, which is part of a wider middleware architecture, accommodates 'overlay plug-ins', allows physical nodes to support multiple overlays, supports the stacking of overlays to create composite protocols, and adopts a declarative approach to configurable deployment and dynamic reconfigurability. The framework has been in development for a number of years and supports an extensive range of overlay plug-ins including popular protocols such as Chord and Pastry. We report on our experiences with the open overlays framework, evaluate it in detail, and illustrate its application in a detailed case study of network heterogeneity.