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Theoretical and Experimental Study of Barium Zinc-Cadmium Tantalate-based Microwave Dielectrics

MRS Online Proceedings Library (OPL) 2011年第1期783卷 B4.7-B4.7页

作者： Shaojun Liu Mark Van Schilfgaarde Jian Sun Louisa Badd David Smith Novak S. Petrovixc R. Taylor N. Newman Chemical and Materials Engineering Department Science and Engineering of Materials Program Center for Solid State Science Arizona State University Tempe AZ 85287–6006 Electrical and Computer Engineering Department Queens land University Paddington Australia 4064

Single-phase Ba(Cd1/3Ta2/3)O3 ceramics have been produced using conventional powder processing methods. In our initial investigations, 2wt% ZnO powder was added to act as a sintering aid since a high-density ceramic was not formed from solid-state diffusion alone. The resulting Ba(Cd0.327Zn0.006Ta2/3)O3 material sintered at 1550° C exhibits a dielectric constant of ∼33 and loss tangent of <5×10−5 at 2 GHz. In our more recent work, we have used boron as a sintering aid to facilitate sintering at temperatures as low as 1300° C, enhance the structural quality and improve the microwave properties of Ba(Cd1/3Ta2/3)O3 dielectrics. TEM results indicate that the liquid sintering mechanism is an important factor for boron concentrations exceeding 0.5wt%, while a point defect mechanism plays the dominant role at lower boron concentrations. The presence of superstructure peaks and splitting of the (220) and (214) peaks in X-ray diffraction spectra are direct evidence for the distortion from cubic symmetry as a result of Cd and Ta ordering on the ***-initio electronic structure calculations within the local density functional approximation have been used to give insight into the unusual properties of this class of materials. In both Ba(Zn1/3Ta2/3)O3 and Ba(Cd/3Ta2/3)O3, the conduction band maximum and valence band minimum are composed of mostly weakly itinerant Ta 5d-and Zn-3d/Cd-4d levels, respectively. The covalent nature of the directional d-electron bonding in these high-Z oxides plays an important role in producing a more rigid lattice with higher melting points and enhanced phonon energies, and possibly inherently lower intrinsic microwave loss than comparable ionic materials.

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Structural Characterization of Nc-Si/A-Sio 2 Superlattices Subjected To Thermal Treatment

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MRS Online Proceedings Library 2011年第1期536卷 141-146页

作者： G. F. Grom L. Tsybeskov K. D. Hirschman P. M. Fauchet J. P. McCaffrey H. J. Labbé D. J. Lockwood Department of Mechanical Engineering Materials Science Program USA Department of Electrical and Computer Engineering University of Rochester Rochester USA Institute for Microstructural Sciences National Research Council Ottawa Canada

The morphology of nanocrystalline (nc)-Si/amorphous (a)-SiO2 superlattices (SLs) is studied using Raman spectroscopy in the acoustic and optical phonon ranges, transmission electron microscopy (TEM), and atomic force microscopy (AFM). It is demonstrated that high temperature annealing (up to 1100°C) and oxidation in O2/H2O ambient do not destroy the SL structure, which retains its original periodicity and nc-Si/a-SiO2 interface abruptness. It is found that oxidation at high temperatures reduces the defect density in nc-Si/a-SiO2 SLs and induces the lateral coalescence of Si nanocrystals (NCs). The size, shape, packing density, and crystallographic orientation of the Si nanocrystals are studied as a function of the oxidation time.

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Hardware Particle Swarm Optimization with passive congregation for embedded applications

Hardware Particle Swarm Optimization with passive congregati...

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Southern Conference on programmable Logic

作者： Muñoz, Daniel M. Llanos, Carlos H. Coelho, Leandro Dos S. Ayala-Rincón, Mauricio Department of Mechanical Engineering Automation and Control Group/GRACO University of Brasilia Brasilia D.F. Brazil Industrial and Systems Engineering Graduate Program Pontifical Catholic University of Parana Curitiba Parana Brazil Department of Computer Science and Mathematics University of Brasilia Brasilia D.F. Brazil

ISBN: (纸本)9781424488483

Achieving high performance optimization algorithms for embedded applications can be very challenging, particularly when several requirements such as high accuracy computations, short elapsed time, area cost, low power consumption and portability must be accomplished. This paper proposes a hardware implementation of the Particle Swarm Optimization algorithm with passive congregation (HPPSOpc), which was developed using several floating-point arithmetic libraries. The passive congregation is a biological behavior which allows the swarm to preserve its integrity, balancing between global and local search. The HPPSOpc architecture was implemented on a Virtex5 FPGA device and validated using two multimodal benchmark problems. Synthesis, simulation and execution time results demonstrates that the passive congregation approach is a low cost solution for solving embedded optimization problems with a high performance. © 2011 IEEE.

关键词： Digital arithmetic

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Design of interval type-2 fuzzy logic controllers for flocking algorithm

Design of interval type-2 fuzzy logic controllers for flocki...

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IEEE International Conference on Fuzzy Systems (FUZZ-IEEE)

作者： Seung-Mok Lee Jong-Hwan Kim Hyun Myung Department of Civil and Environmental Engineering Robotics Program KAIST Daejeon South Korea Department of Electrical Engineering and Computer Science Robotics Program KAIST Daejeon South Korea

This paper presents a novel interval type-2 fuzzy logic control architecture for flocking system when the system has noisy sensor measurements. The traditional type-1 fuzzy logic controller (FLC) using precise type-1 fuzzy sets cannot fully model and handle the uncertainties of sensor data. However, type-2 FLC using type-2 fuzzy sets with a footprint of uncertainty (FOU) produces better performances under noisy environments. In this paper, therefore, we present a reactive control architecture for flocking algorithm that is based on interval type 2 FLC to implement the flocking behaviors consisting separation, obstacle avoidance, and velocity matching behaviors. The type-2 based control system could cope with the uncertainties of noisy sensor measurements and resulted in good performances that outperformed the type-1 FLC.

关键词： Collision avoidance Robot sensing systems Trajectory Fuzzy sets Fuzzy logic Noise measurement

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Assessing Directed Information as a Method for Inferring Functional Connectivity in Neural Ensembles

Assessing Directed Information as a Method for Inferring Fun...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： Kelvin So Michael Gastpar Jose M. Carmena Department of Electrical Engineering and Computer Sciences University of California Department of Electrical Engineering and Computer Sciences the Program in Cognitive Science and the Helen Wills Neuroscience Institute University of California

ISBN: (纸本)9781424441211

Neurons in the brain form complicated networks through synaptic connections. Traditionally, functional connectivity between neurons has been analyzed using simple metrics such as correlation, which do not provide direction of influence. Recently, an information theoretic measure known as directed information has been proposed as a way to capture directionality in the relationship, thereby moving towards a model of effective connectivity. This measure is grounded upon the concept of Granger causality and can be estimated by modeling neural spike trains as point process generalized linear models. However, the added benefit of using directed information to infer connectivity over conventional methods such as correlation is still unclear. Here, we propose a novel estimation procedure for the directed information. Using physiologically realistic simulations, we demonstrate that directed information can outperform correlation in determining connections between neural spike trains while also providing directionality of the relationship, which cannot be assessed using correlation.

关键词： Neurons Correlation Topology Computational modeling Accuracy Brain modeling Measurement

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Temporal dietary patterns using kernel k-means clustering

Temporal dietary patterns using kernel k-means clustering

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13th IEEE International Symposium on Multimedia, ISM 2011

作者： Khanna, Nitin Eicher-Miller, Heather A. Boushey, Carol J. Gelfand, Saul B. Delp, Edward J. School of Electrical and Computer Engineering Purdue University West Lafayette IN United States Department of Nutrition Science Purdue University West Lafayette IN United States Epidemiology Program University of Hawaii Cancer Center Honolulu HI United States

ISBN: (纸本)9780769545899

Chronic diseases, such as heart disease, diabetes, and obesity, have been linked with diet. Nutrient intake is also associated with diet. However, much of the research completed to elucidate these associations has not incorporated the concept of time. This paper introduces the concept of temporal dietary patterns and demonstrates a novel construct of 24-hour temporal dietary patterns for energy intake, present in a sample of the adult U.S. population 20 years and older (NHANES 1999-2004 dataset). An appropriate distance metric is proposed for comparing 24-hour diet records and is used with kernel k-means clustering to identify the temporal dietary patterns. © 2011 IEEE.

关键词： Diseases

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Ant-inspired search techniques for solving the zero-one knapsack problem with multiple constraints

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International Journal of Advancements in Computing Technology 2011年第4期3卷 242-255页

作者： Chiang, Chuan-Wen Huang, Yu-Qing Lu, Guo-Qin Lin, Shou-Sheu Department of Computer and Communication Engineering National Kaohsiung First University of Science and Technology Taiwan Institute of Engineering Science and Technology National Kaohsiung First University of Science and Technology Taiwan Planning and Design Division Southern District Branch Chunghwa Telecommunication Taiwan

In this paper, we consider the multidimensional zero-one knapsack problem (0-1 MKP). The objective of the problem is to find a subset of objects that yields maximum profit without violating knapsack constraints. The 0-1 MKP is known to be NP-hard. Due to the intractability of the problem, numerous research efforts have focused on various approximation algorithms to acquire satisfactory suboptimal solutions within a reasonable amount of computation cost. However, most realistic approaches for solving the 0-1 MKP still remain to be improved. On the basis of ant colony optimization, we therefore propose a novel constructive algorithm. The proposed algorithm, namely AST-MKP, adopts a new type of constructive graph for leading artificial ants in making decisions to select effective solution components. Moreover, we also devise a local search scheme to advance the quality of solutions obtained. The performance of the AST-MKP algorithm is demonstrated by comparing it against other existing algorithms in terms of overall profit for a set of problem instances obtained form the OR-Library. Experimental results indicate that the algorithm proposed here performs significantly better than the competitive approaches.

关键词： Ant colony optimization

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Fractal artistic algorithm structure and image production

Fractal artistic algorithm structure and image production

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2011 International Conference on Advanced Materials and computer science(ICAMCS 2011)

作者： Duan ai-ling duan qiong-bo Century college Beijing University of posts and telecommunication Department of Computer Science of Technology University of Henan Engineering College of the Armed Police Force Xi'an

The fractal art graphic is one of the main manifestations of fractal art,which can be produced through mathematical models and programming on a computerThe paper investigates the designing concept of fractal art based on its self similarity and the iterative method,elaborates in detail the algorithms and steps of several kind of typical fractal graphics,and by properly inserting some controlling variables,has generated a large number of exquisite and inspiring fractal graphics using the JAVA programming language,confirming the validity and usability of presented algorithm's

关键词： Fractal art image algorithm structure JAVA

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Fast handoff implementation using distance measurements between mobile station and APs

Fast handoff implementation using distance measurements betw...

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IEEE Students' Technology Symposium (TechSym)

作者： Debabrata Sarddar Joydeep Banerjee Tathagata Chakraborti Abhronil Sengupta M.K. Naskar Tapas Jana Utpal Biswas Department of Electronics and Telecommunication Engineering Jadavpur University Kolkata India Department of Electronics and Communication Engineering Netaji Subhash Engineering College Kolkata India Department of Computer Science and Engineering University of Kalyani Kalyani West Bengal India

ISBN: (纸本)9781424489411

The rapid growth in IEEE 802.11 based wireless LANs has led to new implementations like VoIP applications that require seamless handover. But handoff delays provide a serious barrier for such services to be made available to mobile platforms. Throughout the last few years there has been plenty of research aimed towards reducing the handoff delay incurred in the various levels of wireless communication. Here we propose new scanning method in which we determine the distance of nearest access points from the mobile node to bypass the main processes involved in increasing MAC layer handoff latency.

关键词： Indexes Media Approximation methods

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Opposition-based shuffled PSO with passive congregation applied to FM matching synthesis

Opposition-based shuffled PSO with passive congregation appl...

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IEEE Congress on Evolutionary Computation

作者： Munoz, Daniel M. Llanos, Carlos H. Dos S. Coelho, Leandro Ayala-Rincon, Mauricio Department of Mechanical Engineering Automation and Control Group/GRACO University of Brasilia Brasilia D.F. Brazil Industrial and Systems Engineering Graduate Program LAS/PPGEPS Pontifical Catholic University of Parana Curitiba Parana Brazil Department of Computer Science and Mathematics University of Brasilia Brasilia D.F. Brazil

ISBN: (纸本)9781424478347

Synthesis of musical instruments or human voice is a time consuming process which requires theoretical and experimental knowledge about the synthesis engine. Commonly, performers need to deal with synthesizer interfaces and a process of trial and error for creating musical sounds similar to a target sound. This drawback can be overcome by adjusting automatically the synthesizer parameters using optimization algorithms. In this paper a hybrid particle swarm optimization (PSO) algorithm is proposed to solve the frequency modulation (FM) matching synthesis problem. The proposed algorithm takes advantage of a shuffle process for exchanging information between particles and applies the selective passive congregation and the opposition-based learning approaches to preserve swarm diversity. Both approaches for injecting diversity are based on simple operators, preserving the easy implementation philosophy of the particle swarm optimization. The proposed hybrid particle swarm optimization algorithm was validated for a three-nested FM synthesizer, which represents a 6-dimensional multimodal optimization problem with strong epistasis. Simulation results revealed that the proposed algorithm presented promising results in terms of quality of solutions. © 2011 IEEE.

关键词： Global optimization

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