Optimization of antenna configuration in multiple-frequency ground penetrating radar system for railroad substructure assessment

This paper discusses the use of ground penetrating radar (GPR) to rapidly, effectively, and continuously assess railroad track substructure conditions, especially ballast. To overcome the limited electromagnetic waves penetration for high-frequency antennae and the low resolution of low-frequency antennae, this study uses a multiple-frequency GPR system to assess railroad substructure conditions. High-frequency antennae were used to detect the scattering pattern, which is related to air void volume in railroad ballast, and low-frequency antennae are used to assess deeper substructure conditions. Considering the scattering energy attenuation is highly frequency and material dependent, a time–frequency method based on tracking the frequency spectrum and energy change over depth can be used to extract ballast fouling conditions. From GPR field collected data, ground-truth observation, and ballast gradation analysis, the multiple-frequency GPR system demonstrates a promising capability to assess railroad track substructure condition.     

Experiments and numerical approaches to ductile tearing in an 2024-T351 aluminium alloy

Ductile fracture of an 2024-T351 aluminium alloy has been investigated using a central crack panel (CCP). In order to predict rupture, two models using the local approach to fracture mechanics were verified: the uncoupled Rice and Tracey void growth model and the coupled Rousselier model based on continuum damage mechanics. A finite element analysis has been performed in order to verify the capability of these models to predict the crack extension.     

The effect of sugars on the diffusion of water in starch gels: a pulsed field gradient NMR study

The self-diffusion coefficient of water was measured in starch–sugar–water systems of various compositions. The starch was either waxy maize or potato starch and the sugar was either sucrose or xylose. The diffusion results obtained from sugar solutions (i.e. with a zero polymer concentration) suggested that a free water behaviour should only be expected after a bilayer coverage of the sugar molecule. The presence of sugars was found to decrease considerably the translational mobility of water in starch gels. This reduction was proportional to the sugar concentration in the system but showed little dependence on the type of sugar. An attempt was made to relate the self-diffusion coefficients of water in starch–sugar–water gels to those obtained for the individual binary systems (starch–water and sugar–water). A prediction based on the additive effects of sugar and starch only corresponded with experimental results in dilute systems.     

Cache modeling and optimization for portable devices running MPEG-4 video decoder

There are increasing demands on portable communication devices to run multimedia applications. ISO (an International Organization for Standardization) standard MPEG-4 is an important and demanding multimedia application. To satisfy the growing consumer demands, more functions are added to support MPEG-4 video applications. With improved CPU speed, memory sub-system deficiency is the major barrier to improving the system performance. Studies show that there is sufficient reuse of values for caching that significantly reduce the memory bandwidth requirement for video data. Software decoding of MPEG-4 video data generates much more cache-memory traffic than required. Proper understanding of the decoding algorithm and the composition of its data set is obvious to improve the performance of such a system. The focus of this paper is cache modeling and optimization for portable communication devices running MPEG-4 video decoding algorithm. The architecture we simulate includes a digital signal processor (DSP) for running the MPEG-4 decoding algorithm and a memory system with two levels of caches. We use VisualSim and Cachegrind simulation tools to optimize cache sizes, levels of associativity, and cache levels for a portable device decoding MPEG-4 video. Abu Asaduzzaman is, currently, a PhD candidate in the department of Computer Science and Engineering (CSE), Florida Atlantic University (FAU), Boca Raton, Florida. He received his MS degree in computer engineering from FAU in 1997. Mr. Asaduzzaman worked for ECI Telecom as a software engineer from 1998 to 2001. From 2001 to 2003, he worked for BlueCross and BlueShield of Florida and SunPass (FDoT) as an IT Consultant. Currently, he is working as a research assistant at CSE Dept, FAU. His research interests include cache optimization, architecture exploration, embedded system evaluation, and networks-on-a-chip (NoC). He has published several research papers in these areas. Abu is a member of the honor society of Phi Kappa Phi, Tau Beta Pi, Upsilon Phi Epsilon, and the Association for Computing Machinery (ACM) FAU Chapter. Imad Mahgoub received the MS degree in applied mathematics and MS degree in electrical and computer engineering, both from North Carolina State University, Raleigh in 1983 and 1986 respectively and the PhD degree in computer engineering from the Pennsylvania State University, University Park, PA in 1989. Dr. Mahgoub joined Florida Atlantic University (FAU), Boca Raton, Florida in 1989. Currently he is a full professor of Computer Science and Engineering department and the director of the Mobile Computing Laboratory. His research interests include performance evaluation, mobile computing, sensor networks, and parallel and distributed processing. He has published over 80 research papers in these areas. He is the co-editor of the Mobile Computing Handbook and the Handbook of Sensor Networks. Dr. Mahgoub has served on the program committees of numerous conferences. He has been the vice-chair for the Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS) since 2003. He is a senior member of the IEEE. He is also a member of Tau Beta Pi, Upsilon Pi Epsilon, the IEEE Computer Society, and the ACM.     

Exploiting edge semantics in citation graphs using efficient, vertical ARM

Graphs are increasingly becoming a vital source of information within which a great deal of semantics is embedded. As the size of available graphs increases, our ability to arrive at the embedded semantics grows into a much more complicated task. One form of important hidden semantics is that which is embedded in the edges of directed graphs. Citation graphs serve as a good example in this context. This paper attempts to understand temporal aspects in publication trends through citation graphs, by identifying patterns in the subject matters of scientific publications using an efficient, vertical association rule mining model. Such patterns can (a) indicate subject-matter evolutionary history, (b) highlight subject-matter future extensions, and (c) give insights on the potential effects of current research on future research. We highlight our major differences with previous work in the areas of graph mining, citation mining, and Web-structure mining, propose an efficient vertical data representation model, introduce a new subjective interestingness measure for evaluating patterns with a special focus on those patterns that signify strong associations between properties of cited papers and citing papers, and present an efficient algorithm for the purpose of discovering rules of interest followed by a detailed experimental analysis. Imad Rahal is a newly appointed assistant professor in the Department of Computer Science at the College of Saint Benedict ∣ Saint John's University, Collegeville, MN, and a Ph.D. candidate at North Dakota State University, Fargo, ND. In August 2003, he earned his master's degree in computer science from North Dakota State University. Prior to that, he graduated summa cum laude from the Lebanese American University, Beirut, Lebanon, in February 2001 with a bachelor's degree in computer science. Currently, he is completing the final requirements for his Ph.D. degree in computer science on an NSF ND-EPSCoR doctoral dissertation assistantship with August of 2005 as a projected completion date. He is very active in research, proposal writing, and publications; his research interests are largely in the broad areas of data mining, machine learning, databases, artificial intelligence, and bioinformatics. Dongmei Ren is working for the Database Technology Institute for z/OS, IBM Silicon Valley Lab, San Jose, CA, as a staff software engineer. She holds a Ph.D. degree from North Dakota State University, Fargo, ND, and master's and bachelor's degrees from TianJin University, TianJin, China. She has been a software engineer at DaTang Telecommunications, Beijing, China. Her areas of expertise are outlier analysis, data mining and knowledge discovery, database systems, machine learning, intelligent systems, wireless networks and bioinformatics. She has been awarded the Siemens Scholarship research enhancement for excellent performance in study and research. She is a member of ACM, IEEE. Weihua Wu is a network monitoring & managed services analyst at Hewlett-Packard Co. in Canada. He holds a master's degree from North Dakota State University and a bachelor's degree from Nanjing University, both in computer science. His research areas of interest include data mining, knowledge discovery, data warehousing, information technology, network security, and bioinformatics. He has participated in various projects supported by NSF, DARPA, NASA, USDA, and GSA grants. Anne Denton is an assistant professor in computer science at North Dakota State University. Her research interests are in data mining, knowledge discovery in scientific data, and bioinformatics. Specific interests include data mining of diverse data, in which objects are characterized by a variety of properties such as numerical and categorical attributes, graphs, sequences, time-dependent attributes, and others. She received her Ph.D. in physics from the University of Mainz, Germany, and her M.S. in computer science from North Dakota State University, Fargo, ND. Christopher Besemann received his M.Sc. in computer science from North Dakota State University in Fargo, ND, 2005. Currently, he works in data mining research topics including association mining and relational data mining with recent work in model integration as a research assistant. He is accepted under a fellowship program for Ph.D. study at North Dakota State University. William Perrizo is a professor of computer science at North Dakota State University. He holds a Ph.D. degree from the University of Minnesota, a master's degree from the University of Wisconsin and a bachelor's degree from St. John's University. He has been a research scientist at the IBM Advanced Business Systems Division and the U.S. Air Force Electronic Systems Division. His areas of expertise are data mining, knowledge discovery, database systems, distributed database systems, high speed computer and communications networks, precision agriculture and bioinformatics. He is a member of ISCA, ACM, IEEE, IAAA, and AAAS.     

Oxidation of atmospheric humic like substances by ozone: a kinetic and structural analysis approach

This work explores the heterogeneous reaction between HUmic-LIke Substances (so-called HULIS) and ozone. Genuine atmospheric HULIS were extracted from aerosol samples collected in Chamonix (France) in winter and used in coated flow tube experiments to evaluate heterogeneous uptake of O? on such mixtures. The uptake coefficient (γ) was investigated as a function of pH (from 2.5 to 10), O? concentration (from 8 to 33 × 1011 molecules cm?3), relative humidity (20 to 65%) and photon flux (from 0 to 1.66 × 101? photons cm?2 s?1). Reactive uptake was found to increase in the irradiated experiment with pH, humidity and photon flux. The extract was characterized before and after exposure to O? and/or UV light in the attempt to elucidate the effect of the photochemical aging. Carbon content measurements, UV-vis spectroscopy and functional groups analysis revealed a decrease of the UV absorbance as well as of the carbon mass content, while the functionalization rate (COOH and C═O) and therefore the polarity increased during the simulated photochemical exposure.     

Analysis on failure mechanisms of an interlock woven fabric under ballistic impact

In this paper, damage mechanisms of a 3D interlock woven fabric subjected to ballistic impact were analyzed using a numerical model. Two impact configurations were carried out in order to validate the numerical model with experimental observations: perforation (900 m/s) and no-perforation (90 m/s). Global deformation of the fabric during impact is determined continuously to detail fabric impact behavior. Also, in this study, the effects of boundary conditions on failure mechanisms have been investigated. Boundary conditions are divided into two cases: (1) only warp yarns fixed and (2) only weft yarns fixed. Basing on continuous evolutions of global deformation, projectile velocity, different energies and reaction force onto projectile, the influence of both these fixation conditions is investigated.     

Date consumption and dietary significance in the United Arab Emirates

Date consumption in the United Arab Emirates was determined among different subgroups of the nation's society. Adult consumers of both sexes and different age groups (18–30 and 30–60) and occupations (students, workers, at home) were surveyed for information on their daily consumption of six date food groups (rutab, tamr, seh, debbs, batheeth and madlouj). Percentage distribution of portion size, frequency of consumption and season, over different consumer groups per date food group, were determined. Differences in the daily consumption of every date food group within and among the different population groups were tested. The most consumed date food groups were rutab and tamr, with rutab being more frequently consumed than tamr during the summer season. Overall, no major differences were observed in average daily consumption per capita of most of the date food groups between males and females, between employed and home‐based consumers, and between students and individuals of 18–30 years old. On average, daily consumption of dates per capita was 114.3 g, equivalent to 10 date fruits. However, it was noted that the younger population does not consume dates as much as the older population does. Nevertheless, data obtained highlighted the significance of dates in the UAE nation's diet considering the relatively high average consumption of dates per capita. Copyright © 2006 Society of Chemical Industry     

Energy supply security and geopolitics: A European perspective

The security of energy supply to the EU is examined in the context of two storylines. Markets and Institutions exemplifies an economically and politically integrated, multilateral world with effective institutions and markets. Regions and Empires involves a world broken up in rival political and economic blocks, competing for resources and markets via political, economic and military power. It is shown that these storylines have a significant impact on the development of the energy market, on the way in which energy supply may be secured and on the effect and applicability of the several types of instruments available. The current EU is geared towards enlargement and a deepening of economic integration, based on the tenets of the post-1945 multilateral world system. The present world tends towards Regions and Empires and suggests that the EU may have to reorient its energy security policy. Energy policy must become an integral part of EU external trade and foreign relations and security policy. The EU should develop its own strategy, actively investing in dialogues with producer countries in the Persian Gulf and Africa and with Russia. Sustainable prosperity and governance in these regions will support EU energy security.