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Full-Text Articles in Physical Sciences and Mathematics

Ict For Poverty Alleviation In Pacific Island Nations: Study Of Icts4d In Fiji, Deogratias Harorimana, Opeti Rokotuinivono, Emali Sewale, Fane Salaiwai, Marica Naulu, Evangelin Roy Dec 2012

Ict For Poverty Alleviation In Pacific Island Nations: Study Of Icts4d In Fiji, Deogratias Harorimana, Opeti Rokotuinivono, Emali Sewale, Fane Salaiwai, Marica Naulu, Evangelin Roy

Dr Deogratias Harorimana

ICT for Poverty Alleviation in Pacific Island Nations: Study of ICTs4D in Fiji There has been a vague and little knowledge on the role or potential of Information and Communications Technologies (ICTs) in relation to addressing poverty in Fiji. This may be probably due to the newness of the technology in the South Pacific Region as a whole but also probably due to the fact that only 9.7% of the current Fiji 931,000 populations are internet users (ITC Figures 2011). This paper reports on finding how ICTs is contributing towards poverty alleviation in Fiji. On the basis of reviewed best …


Scaling Bayesian Network Parameter Learning With Expectation Maximization Using Mapreduce, Erik B. Reed, Ole J. Mengshoel Nov 2012

Scaling Bayesian Network Parameter Learning With Expectation Maximization Using Mapreduce, Erik B. Reed, Ole J. Mengshoel

Ole J Mengshoel

Bayesian network (BN) parameter learning from incomplete data can be a computationally expensive task for incomplete data. Applying the EM algorithm to learn BN parameters is unfortunately susceptible to local optima and prone to premature convergence. We develop and experiment with two methods for improving EM parameter learning by using MapReduce: Age-Layered Expectation Maximization (ALEM) and Multiple Expectation Maximization (MEM). Leveraging MapReduce for distributed machine learning, these algorithms (i) operate on a (potentially large) population of BNs and (ii) partition the data set as is traditionally done with MapReduce machine learning. For example, we achieved gains using the Hadoop implementation …


Mapreduce For Bayesian Network Parameter Learning Using The Em Algorithm, Aniruddha Basak, Irina Brinster, Ole J. Mengshoel Nov 2012

Mapreduce For Bayesian Network Parameter Learning Using The Em Algorithm, Aniruddha Basak, Irina Brinster, Ole J. Mengshoel

Ole J Mengshoel

This work applies the distributed computing framework MapReduce to Bayesian network parameter learning from incomplete data. We formulate the classical Expectation Maximization (EM) algorithm within the MapReduce framework. Analytically and experimentally we analyze the speed-up that can be obtained by means of MapReduce. We present details of the MapReduce formulation of EM, report speed-ups versus the sequential case, and carefully compare various Hadoop cluster configurations in experiments with Bayesian networks of different sizes and structures.


Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam Oct 2012

Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …


Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam Oct 2012

Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …


Embedded Virtual Machines For Robust Wireless Control Systems, Rahul Mangharam, Miroslav Pajic Oct 2012

Embedded Virtual Machines For Robust Wireless Control Systems, Rahul Mangharam, Miroslav Pajic

Rahul Mangharam

Embedded wireless networks have largely focused on open loop sensing and monitoring. To address actuation in closed loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology of wireless systems are inherently unreliable, such time-critical and safety-critical applications require programming abstractions where the tasks are assigned to the sensors, actuators and controllers as a single component rather than statically mapping a set of tasks to a specific physical node at design time. To this end, we introduce the Embedded Virtual Machine (EVM), a …


Embedded Virtual Machines For Robust Wireless Control And Actuation, Miroslav Pajic, Rahul Mangharam Oct 2012

Embedded Virtual Machines For Robust Wireless Control And Actuation, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

Embedded wireless networks have largely focused on open-loop sensing and monitoring. To address actuation in closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology of wireless systems are inherently unreliable, such time-critical and safety-critical applications require programming abstractions and runtime systems where the tasks are assigned to the sensors, actuators and controllers as a single component rather than statically mapping a set of tasks to a specific physical node at design time. To this end, we introduce the Embedded Virtual Machine (EVM), …


Software And System Health Management For Autonomous Robotics Missions, Johann Schumann, Timmy Mbaya, Ole J. Mengshoel Sep 2012

Software And System Health Management For Autonomous Robotics Missions, Johann Schumann, Timmy Mbaya, Ole J. Mengshoel

Ole J Mengshoel

Advanced autonomous robotics space missions rely heavily on the flawless interaction of complex hardware, multiple sensors, and a mission-critical software system. This software system consists of an operating system, device drivers, controllers, and executives; recently highly complex AI-based autonomy software have also been introduced. Prior to launch, this software has to undergo rigorous verification and validation (V&V). Nevertheless, dormant software bugs, failing sensors, unexpected hardware-software interactions, and unanticipated environmental conditions—likely on a space exploration mission—can cause major software faults that can endanger the entire mission.

Our Integrated Software Health Management (ISWHM) system continuously monitors the hardware sensors and the software …


Reactive Bayesian Network Computation Using Feedback Control: An Empirical Study, Ole J. Mengshoel, Abe Ishihara, Erik Reed Aug 2012

Reactive Bayesian Network Computation Using Feedback Control: An Empirical Study, Ole J. Mengshoel, Abe Ishihara, Erik Reed

Ole J Mengshoel

This paper investigates the challenge of integrating intelligent systems into varying computational platforms and application mixes while providing reactive (or soft real-time) response. We integrate Bayesian network computation with feedback control, thereby achieving our reactive objective. As a case study we investigate fault diagnosis using Bayesian networks. While we consider the likelihood weighting and junction tree propagation Bayesian network inference algorithms in some detail, we hypothesize that the techniques developed can be broadly applied to achieve reactive intelligent systems. In the empirical study of this paper we demonstrate reactive fault diagnosis for an electrical power system.


The Impact Of Social Affinity On Phone Calling Patterns: Categorizing Social Ties From Call Data Records, Sara Motahari, Ole J. Mengshoel, Phyllis Reuther, Sandeep Appala, Luca Zoia, Jay Shah Aug 2012

The Impact Of Social Affinity On Phone Calling Patterns: Categorizing Social Ties From Call Data Records, Sara Motahari, Ole J. Mengshoel, Phyllis Reuther, Sandeep Appala, Luca Zoia, Jay Shah

Ole J Mengshoel

Social ties defined by phone calls made between people can be grouped to various affinity networks, such as family members, utility network, friends, coworkers, etc. An understanding of call behavior within each social affinity network and the ability to infer the type of a social tie from call patterns is invaluable for various industrial purposes. For example, the telecom industry can use such information for consumer retention, targeted advertising, and customized services. In this paper, we analyze the patterns of 4.3 million phone call data records produced by 360,000 subscribers from two California cities. Our findings can be summarized as …


Accelerating Bayesian Network Parameter Learning Using Hadoop And Mapreduce, Aniruddha Basak, Irina Brinster, Xianheng Ma, Ole J. Mengshoel Aug 2012

Accelerating Bayesian Network Parameter Learning Using Hadoop And Mapreduce, Aniruddha Basak, Irina Brinster, Xianheng Ma, Ole J. Mengshoel

Ole J Mengshoel

Learning conditional probability tables of large Bayesian Networks (BNs) with hidden nodes using the Expectation Maximization algorithm is heavily computationally intensive. There are at least two bottlenecks, namely the potentially huge data set size and the requirement for computation and memory resources. This work applies the distributed computing framework MapReduce to Bayesian parameter learning from complete and incomplete data. We formulate both traditional parameter learning (complete data) and the classical Expectation Maximization algorithm (incomplete data) within the MapReduce framework. Analytically and experimentally we analyze the speed-up that can be obtained by means of MapReduce. We present the details of our …


Adaptive Control Of Bayesian Network Computation, Erik Reed, Abe Ishihara, Ole J. Mengshoel Jul 2012

Adaptive Control Of Bayesian Network Computation, Erik Reed, Abe Ishihara, Ole J. Mengshoel

Ole J Mengshoel

This paper considers the problem of providing, for computational processes, soft real-time (or reactive) response without the use of a hard real-time operating system. In particular, we focus on the problem of reactively computing fault diagnosis by means of different Bayesian network inference algorithms on non-real-time operating systems where low-criticality (background) process activity and system load is unpredictable.
To address this problem, we take in this paper a reconfigurable adaptive control approach. Computation time is modeled using an ARX model where the input consists of the maximum number of background processes allowed to run at any given time. To ensure …


Switch Yard Operation In Thermal Power Plant(Katpp Jhalawar Rajasthan), Radhey Shyam Meena Er. Jul 2012

Switch Yard Operation In Thermal Power Plant(Katpp Jhalawar Rajasthan), Radhey Shyam Meena Er.

Radhey Shyam Meena

Switchyard Provides the facilities for switching ,protection & Control of electric power. To handle high Voltage power with proper Safety measures. To isolate the noises coming from the grid with true 50Hz power SWITCH YARD IS IMPORTANT PART IN THERMAL PLANT. IN KALISINDH THERMAL 400KV AND 220KV SWITCH YARD LOCATED.


Capacitively Coupled Radio-Frequency Discharges In Nitrogen At Low Pressures, L. L Alves, L. Marques, C. D Pintassilgo, W. Wattieaux, Et. Es-Sebbar, J. Berndt, E. Kovačević, N. Carrasco, L. Boufendi, G. Cernogora Jul 2012

Capacitively Coupled Radio-Frequency Discharges In Nitrogen At Low Pressures, L. L Alves, L. Marques, C. D Pintassilgo, W. Wattieaux, Et. Es-Sebbar, J. Berndt, E. Kovačević, N. Carrasco, L. Boufendi, G. Cernogora

Dr. Et-touhami Es-sebbar

This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56 MHz frequency, 0.1–1 mbar pressures and 2–30 W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an …


Size-Dependent Metal-Insulator Transition In Pt-Dispersed Sio2 Thin Film: A Candidate For Future Non-Volatile Memory, Albert B. Chen Jun 2012

Size-Dependent Metal-Insulator Transition In Pt-Dispersed Sio2 Thin Film: A Candidate For Future Non-Volatile Memory, Albert B. Chen

Albert B Chen

Non-volatile random access memories (NVRAM) are promising data storage and processing devices. Various NVRAM, such as FeRAM and MRAM, have been studied in the past. But resistance switching random access memory (RRAM) has demonstrated the most potential for replacing flash memory in use today. In this dissertation, a novel RRAM material design that relies upon an electronic transition, rather than a phase change (as in chalcogenide Ovonic RRAM) or a structural change (such in oxide and halide filamentary RRAM), is investigated. Since the design is not limited to a single material but applicable to general combinations of metals and insulators, …


Ionization Photophysics And Rydberg Spectroscopy Of Diacetylene, M. Schwell, Y. Benilan, N.. Fray, M.-C. Gazeau, Et. Es-Sebbar, F.-G. Levrel, N. Campion, S. Leach Jun 2012

Ionization Photophysics And Rydberg Spectroscopy Of Diacetylene, M. Schwell, Y. Benilan, N.. Fray, M.-C. Gazeau, Et. Es-Sebbar, F.-G. Levrel, N. Campion, S. Leach

Dr. Et-touhami Es-sebbar

Photoionization of diacetylene was studied using synchrotron radiation over the range 8–24 eV, with photoelectron-photoion coincidence (PEPICO) and threshold photoelectron–photoion coincidence (TPEPICO) techniques. Mass spectra, ion yields, total and partial ionization cross-sections were measured. The adiabatic ionization energy of diacetylene was determined as IEad = (10.17 ± 0.01) eV, and the appearance energy of the principal fragment ion C4H+ as AE = (16.15 ± 0.03) eV. Calculated appearance energies of other fragment ions were used to infer aspects of dissociation pathways forming the weaker fragment ions , C3H+, and C2H+. Structured autoionization features observed in the PEPICO spectrum of diacetylene …


Emp And Geomagnetic Storm Protection Of Critical Infrastructure, George H. Baker Iii May 2012

Emp And Geomagnetic Storm Protection Of Critical Infrastructure, George H. Baker Iii

George H Baker

EMP and solar storm wide geographic coverage and ubiquitous system effects beg the question of “Where to begin?” with protection efforts. Thus, in addressing these “wide area electromagnetic (EM) effects,” we must be clever in deciding where to invest limited resources. Based on simple risk analysis, the electric power and communication infrastructures emerge as the highest priority for EM protection. Programs focused on these highest risk infrastructures will go a long way in lessoning societal impact. Given the national scope of the effects, such programs must be coordinated at the national level but implemented at local level. Because wide-area EM …


Performance Analysis Of Nitride Alternative Plasmonic Materials For Localized Surface Plasmon Applications, U. Guler, Gururaj V. Naik, Alexandra Boltasseva, Vladimir M. Shalaev, Alexander V. Kildishev Apr 2012

Performance Analysis Of Nitride Alternative Plasmonic Materials For Localized Surface Plasmon Applications, U. Guler, Gururaj V. Naik, Alexandra Boltasseva, Vladimir M. Shalaev, Alexander V. Kildishev

U. Guler

We consider methods to define the performance metrics for different plasmonic materials to be used in localized surface plasmon applications. Optical efficiencies are shown to be better indicators of performance as compared to approximations in the quasistatic regime. The near-field intensity efficiency, which is a generalized form of the well-known scattering efficiency, is a more flexible and useful metric for local-field enhancement applications. We also examine the evolution of the field enhancement from a particle surface to the far-field regime for spherical nanoparticles with varying radii. Titanium nitride and zirconium nitride, which were recently suggested as alternative plasmonic materials in …


Age-Layered Expectation Maximization For Parameter Learning In Bayesian Networks, Avneesh Saluja, Priya Sundararajan, Ole J. Mengshoel Apr 2012

Age-Layered Expectation Maximization For Parameter Learning In Bayesian Networks, Avneesh Saluja, Priya Sundararajan, Ole J. Mengshoel

Ole J Mengshoel

The expectation maximization (EM) algorithm is a popular algorithm for parameter estimation in models with hidden variables. However, the algorithm has several non-trivial limitations, a significant one being variation in eventual solutions found, due to convergence to local optima. Several techniques have been proposed to allay this problem, for example initializing EM from multiple random starting points and selecting the highest likelihood out of all runs. In this work, we a) show that this method can be very expensive computationally for difficult Bayesian networks, and b) in response we propose an age-layered EM approach (ALEM) that efficiently discards less promising …


Organic Chemistry: A Survival Guide For Students, Ethan C. Levine Apr 2012

Organic Chemistry: A Survival Guide For Students, Ethan C. Levine

Anton Geiler

This project reviews material from undergraduate Organic Chemistry I and II. It is meant to function as a supplement to the textbook and lecture material for the course as it is taught in universities throughout the United States. Complex ideas are broken down into simpler ones. Material is presented in conversational language, using as little scientific jargon as possible.


Volatile Products Controlling Titan’S Tholins Production, N. Carrasco, T. Gautier, Et. Es-Sebbar, P. Pernot, G. Cernogora Mar 2012

Volatile Products Controlling Titan’S Tholins Production, N. Carrasco, T. Gautier, Et. Es-Sebbar, P. Pernot, G. Cernogora

Dr. Et-touhami Es-sebbar

A quantitative agreement between nitrile relative abundances and Titan’s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan’s atmosphere [Gautier et al. (2011) Icarus, 213: 625]. Here we present a complementary study on the same reactor using an in-situ diagnostic of the gas phase composition. Various initial N2-CH4 gas mixtures (methane varying from 1 to 10%) are studied, with a monitoring of the methane consumption and of the stable gas neutrals by in-situ mass spectrometry. Atomic hydrogen is also measured by optical emission spectroscopy. A positive correlation is found between atomic hydrogen abundance and …


Automatic Parameter Selection For Feature-Enhanced Radar Image Restoration, Moeness G Amin, Cher Hau Seng, Son Lam Phung, Abdesselam Bouzerdoum Mar 2012

Automatic Parameter Selection For Feature-Enhanced Radar Image Restoration, Moeness G Amin, Cher Hau Seng, Son Lam Phung, Abdesselam Bouzerdoum

Cher Hau Seng

In this paper, we propose a new technique for optimum parameter selection in non-quadratic radar image restoration. Although both the regularization hyper-parameter and the norm value are influential factors in the characteristics of the formed restoration, most existing optimization methods either require memory intensive computation or prior knowledge of the noise. Here, we present a contrast measure-based method for automated hyper-parameter selection. The proposed method is then extended to optimize the norm value used in non-quadratic image formation and restoration. The proposed method is evaluated on the MSTAR public target database and compared to the GCV method. Experimental results show …


Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas Mar 2012

Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas

George J. Pappas

We consider deployment problems where a mobile robotic network must optimize its configuration in a distributed way in order to minimize a steady-state cost function that depends on the spatial distribution of certain probabilistic events of interest. Three classes of problems are discussed in detail: coverage control problems, spatial partitioning problems, and dynamic vehicle routing problems. Moreover, we assume that the event distribution is a priori unknown, and can only be progressively inferred from the observation of the location of the actual event occurrences. For each problem we present distributed stochastic gradient algorithms that optimize the performance objective. The stochastic …


Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas Mar 2012

Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas

George J. Pappas

We consider deployment problems where a mobile robotic network must optimize its configuration in a distributed way in order to minimize a steady-state cost function that depends on the spatial distribution of certain probabilistic events of interest. Three classes of problems are discussed in detail: coverage control problems, spatial partitioning problems, and dynamic vehicle routing problems. Moreover, we assume that the event distribution is a priori unknown, and can only be progressively inferred from the observation of the location of the actual event occurrences. For each problem we present distributed stochastic gradient algorithms that optimize the performance objective. The stochastic …


Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas Mar 2012

Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas

George J. Pappas

We consider deployment problems where a mobile robotic network must optimize its configuration in a distributed way in order to minimize a steady-state cost function that depends on the spatial distribution of certain probabilistic events of interest. Three classes of problems are discussed in detail: coverage control problems, spatial partitioning problems, and dynamic vehicle routing problems. Moreover, we assume that the event distribution is a priori unknown, and can only be progressively inferred from the observation of the location of the actual event occurrences. For each problem we present distributed stochastic gradient algorithms that optimize the performance objective. The stochastic …


Polaris: Getting Accurate Indoor Orientations For Mobile Devices Using Ubiquitous Visual Patterns On Ceilings, Zheng Sun Feb 2012

Polaris: Getting Accurate Indoor Orientations For Mobile Devices Using Ubiquitous Visual Patterns On Ceilings, Zheng Sun

Zheng Sun

Ubiquitous computing applications commonly use digital compass sensors to obtain orientation of a device relative to the magnetic north of the earth. However, these compass readings are always prone to significant errors in indoor environments due to presence of metallic objects in close proximity. Such errors can adversely affect the performance and quality of user experience of the applications utilizing digital compass sensors.

In this paper, we propose Polaris, a novel approach to provide reliable orientation information for mobile devices in indoor environments. Polaris achieves this by aggregating pictures of the ceiling of an indoor environment and applies computer vision …


Vuv Photoionization Of Acetamide Studied By Electron / Ion Coincidence Spectroscopy In The 8-24 Ev Photon Energy Range, M. Schwell, Y. Bénilan, N. Fray, M.-C Gazeau, Et. Es-Sebbar, Gustavo A. Garcia, L. Nahon, N. Champion, S. Leach Jan 2012

Vuv Photoionization Of Acetamide Studied By Electron / Ion Coincidence Spectroscopy In The 8-24 Ev Photon Energy Range, M. Schwell, Y. Bénilan, N. Fray, M.-C Gazeau, Et. Es-Sebbar, Gustavo A. Garcia, L. Nahon, N. Champion, S. Leach

Dr. Et-touhami Es-sebbar

A VUV photoionization study of acetamide was carried out over the 8-24 eV photon energy range using synchrotron radiation and photoelectron/photoion coincidence (PEPICO) spectroscopy. Threshold photoelectron photoion coincidence (TPEPICO) measurements were also made. Photoion yield curves and branching ratios were measured for the parent ion and six fragment ions. The adiabatic ionization energy of acetamide was determined as I.E (12A’) = (9.71±0.02) eV, in agreement with an earlier reported photoionization mass spectrometry (PIMS) value. The adiabatic energy of the first excited state of the ion, 12A”, was determined to be ≈ 10.1 eV. Assignments of the fragment ions and the …


A Review Of The Professionalization Of The Software Industry: Has It Made Software Engineering A Real Profession?, Heng Ngee Mok Jan 2012

A Review Of The Professionalization Of The Software Industry: Has It Made Software Engineering A Real Profession?, Heng Ngee Mok

Heng Ngee Mok

Every industry strives to be called a "profession", and software engineering is no exception. This paper attempts to define "profession" from three different perspectives and provides a chronological narration of the professionalization efforts of major IT bodies such as the IEEE Computer Society, Association of Computing Machinery and British Computer Society to promote software engineering from "occupation" to "profession". The outcome of this professionalization process is then examined against the three vastly different definitions of "profession" to qualitatively gauge the success of the professionalization process.