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2010

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Full-Text Articles in Engineering

Parallelization Of Geant4 Using Top-C And Marshalgen, Gene D. Cooperman, Viet Ha Nguyen, Igor Maliutov Dec 2010

Parallelization Of Geant4 Using Top-C And Marshalgen, Gene D. Cooperman, Viet Ha Nguyen, Igor Maliutov

Gene D. Cooperman

Geant4 is a very large, highly accurate toolkit for Monte Carlo simulation of particle-matter interaction. It has been applied to high-energy physics, cosmic ray modeling, radiation shields, radiation therapy, mine detection, and other areas. Geant4 is being used to help design some high energy physics experiments (notably CMS and Atlas) to be run on the future large hadron collider: the largest particle collider in the world. The parallelization, ParGeant4, represents a challenge due to the unique characteristics of Geant4: (i) complex object-oriented design; (ii) intrinsic use of templates and abstract classes to be instantiated later by the end user; (iii) …


Tree-Based Partition Querying: A Methodology For Computing Medoids In Large Spatial Datasets, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou Dec 2010

Tree-Based Partition Querying: A Methodology For Computing Medoids In Large Spatial Datasets, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou

Kyriakos MOURATIDIS

Besides traditional domains (e.g., resource allocation, data mining applications), algorithms for medoid computation and related problems will play an important role in numerous emerging fields, such as location based services and sensor networks. Since the k-medoid problem is NP hard, all existing work deals with approximate solutions on relatively small datasets. This paper aims at efficient methods for very large spatial databases, motivated by: (i) the high and ever increasing availability of spatial data, and (ii) the need for novel query types and improved services. The proposed solutions exploit the intrinsic grouping properties of a data partition index in order …


Anonymous Query Processing In Road Networks, Kyriakos Mouratidis, Man Lung Yiu Dec 2010

Anonymous Query Processing In Road Networks, Kyriakos Mouratidis, Man Lung Yiu

Kyriakos MOURATIDIS

The increasing availability of location-aware mobile devices has given rise to a flurry of location-based services (LBSs). Due to the nature of spatial queries, an LBS needs the user position in order to process her requests. On the other hand, revealing exact user locations to a (potentially untrusted) LBS may pinpoint their identities and breach their privacy. To address this issue, spatial anonymity techniques obfuscate user locations, forwarding to the LBS a sufficiently large region instead. Existing methods explicitly target processing in the euclidean space and do not apply when proximity to the users is defined according to network distance …


On-Line Discovery Of Hot Motion Paths, Dimitris Sacharidis, Kostas Patroumpas, Manolis Terrovitis, Verena Kantere, Michalis Potamias, Kyriakos Mouratidis, Timos Sellis Dec 2010

On-Line Discovery Of Hot Motion Paths, Dimitris Sacharidis, Kostas Patroumpas, Manolis Terrovitis, Verena Kantere, Michalis Potamias, Kyriakos Mouratidis, Timos Sellis

Kyriakos MOURATIDIS

We consider an environment of numerous moving objects, equipped with location-sensing devices and capable of communicating with a central coordinator. In this setting, we investigate the problem of maintaining hot motion paths, i.e., routes frequently followed by multiple objects over the recent past. Motion paths approximate portions of objects' movement within a tolerance margin that depends on the uncertainty inherent in positional measurements. Discovery of hot motion paths is important to applications requiring classification/profiling based on monitored movement patterns, such as targeted advertising, resource allocation, etc. To achieve this goal, we delegate part of the path extraction process to objects, …


Continuous Monitoring Of Spatial Queries In Wireless Broadcast Environments, Kyriakos Mouratidis, Spiridon Bakiras, Dimitris Papadias Dec 2010

Continuous Monitoring Of Spatial Queries In Wireless Broadcast Environments, Kyriakos Mouratidis, Spiridon Bakiras, Dimitris Papadias

Kyriakos MOURATIDIS

Wireless data broadcast is a promising technique for information dissemination that leverages the computational capabilities of the mobile devices in order to enhance the scalability of the system. Under this environment, the data are continuously broadcast by the server, interleaved with some indexing information for query processing. Clients may then tune in the broadcast channel and process their queries locally without contacting the server. Previous work on spatial query processing for wireless broadcast systems has only considered snapshot queries over static data. In this paper, we propose an air indexing framework that 1) outperforms the existing (i.e., snapshot) techniques in …


Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis Dec 2010

Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis

Kyriakos MOURATIDIS

Consider a set of customers (e.g., WiFi receivers) and a set of service providers (e.g., wireless access points), where each provider has a capacity and the quality of service offered to its customers is anti-proportional to their distance. The capacity constrained assignment (CCA) is a matching between the two sets such that (i) each customer is assigned to at most one provider, (ii) every provider serves no more customers than its capacity, (iii) the maximum possible number of customers are served, and (iv) the sum of Euclidean distances within the assigned provider-customer pairs is minimized. Although max-flow algorithms are applicable …


Continuous Spatial Assignment Of Moving Users, Leong Hou U, Kyriakos Mouratidis, Nikos Mamoulis Dec 2010

Continuous Spatial Assignment Of Moving Users, Leong Hou U, Kyriakos Mouratidis, Nikos Mamoulis

Kyriakos MOURATIDIS

Consider a set of servers and a set of users, where each server has a coverage region (i.e., an area of service) and a capacity (i.e., a maximum number of users it can serve). Our task is to assign every user to one server subject to the coverage and capacity constraints. To offer the highest quality of service, we wish to minimize the average distance between users and their assigned server. This is an instance of a well-studied problem in operations research, termed optimal assignment. Even though there exist several solutions for the static case (where user locations are fixed), …


Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis Dec 2010

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis

Kyriakos MOURATIDIS

Shortest path computation is one of the most common queries in location-based services that involve transportation net- works. Motivated by scalability challenges faced in the mo- bile network industry, we propose adopting the wireless broad- cast model for such location-dependent applications. In this model the data are continuously transmitted on the air, while clients listen to the broadcast and process their queries locally. Although spatial problems have been considered in this environment, there exists no study on shortest path queries in road networks. We develop the rst framework to compute shortest paths on the air, and demonstrate the practicality and …


Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu Dec 2010

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Kyriakos MOURATIDIS

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate …


Geant4 Developments And Applications, J. Allison, K. Amako, J. Apostolakis, H. Araujo, P. Arce Dubois, M. Asai, G. Barrand, R. Capra, S. Chauvie, R. Chytracek, G. A. P. Cirrone, Gene D. Cooperman, G. Cosmo, G. Cuttone, G. G. Daquino, M. Donszelmann, M. Dressel, G. Folger, F. Foppiano, J. Generowicz, V. Grichine, S. Guatelli, P. Gumplinger, A. Heikkinen, I. Hrivnacova, A. Howard, S. Incerti, V. Ivanchenko, T. Johnson, F. Jones, T. Koi, R. Kokoulin, M. Kossov, H. Kurashige, V. Lara, S. Larsson, F. Lei, O. Link, F. Longo, M. Maire, A. Mantero, B. Mascialino, I. Mclaren, P. Mendez Lorenzo, K. Minamimoto, K. Murakami, P. Nieminen, L. Pandola, S. Parlati, L. Peralta, J. Perl, A. Pfeiffer, M. G. Pia, A. Ribon, P. Rodrigues, G. Russo, S. Sadilov, G. Santin, T. Sasaki, D. Smith, N. Starkov, S. Tanaka, E. Tcherniaev, B. Tomé, A. Trindade, P. Truscott, L. Urban, M. Verderi, A. Walkden, J. P. Wellisch, D. C. Williams, D. Wright, H. Yoshida Dec 2010

Geant4 Developments And Applications, J. Allison, K. Amako, J. Apostolakis, H. Araujo, P. Arce Dubois, M. Asai, G. Barrand, R. Capra, S. Chauvie, R. Chytracek, G. A. P. Cirrone, Gene D. Cooperman, G. Cosmo, G. Cuttone, G. G. Daquino, M. Donszelmann, M. Dressel, G. Folger, F. Foppiano, J. Generowicz, V. Grichine, S. Guatelli, P. Gumplinger, A. Heikkinen, I. Hrivnacova, A. Howard, S. Incerti, V. Ivanchenko, T. Johnson, F. Jones, T. Koi, R. Kokoulin, M. Kossov, H. Kurashige, V. Lara, S. Larsson, F. Lei, O. Link, F. Longo, M. Maire, A. Mantero, B. Mascialino, I. Mclaren, P. Mendez Lorenzo, K. Minamimoto, K. Murakami, P. Nieminen, L. Pandola, S. Parlati, L. Peralta, J. Perl, A. Pfeiffer, M. G. Pia, A. Ribon, P. Rodrigues, G. Russo, S. Sadilov, G. Santin, T. Sasaki, D. Smith, N. Starkov, S. Tanaka, E. Tcherniaev, B. Tomé, A. Trindade, P. Truscott, L. Urban, M. Verderi, A. Walkden, J. P. Wellisch, D. C. Williams, D. Wright, H. Yoshida

Gene D. Cooperman

Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Its functionality and modeling capabilities continue to be extended, while its performance is enhanced. An overview of recent developments in diverse areas of the toolkit is presented. These include performance optimization for complex setups; improvements for the propagation in fields; new options for event biasing; and additions and improvements in geometry, physics processes and interactive …


Adaptive Checkpointing For Master-Worker Style Parallelism (Extended Abstract), Gene D. Cooperman, Jason Ansel, Xiaoqin Ma Dec 2010

Adaptive Checkpointing For Master-Worker Style Parallelism (Extended Abstract), Gene D. Cooperman, Jason Ansel, Xiaoqin Ma

Gene D. Cooperman

No abstract provided.


Dmtcp: Transparent Checkpointing For Cluster Computations And The Desktop, Jason Ansel, Kapil Arya, Gene D. Cooperman Dec 2010

Dmtcp: Transparent Checkpointing For Cluster Computations And The Desktop, Jason Ansel, Kapil Arya, Gene D. Cooperman

Gene D. Cooperman

DMTCP (Distributed MultiThreaded CheckPointing) is a transparent user-level checkpointing package for distributed applications. Checkpointing and restart is demonstrated for a wide range of over 20 well known applications, including MATLAB, Python, TightVNC, MPICH2, OpenMPI, and runCMS. RunCMS runs as a 680 MB image in memory that includes 540 dynamic libraries, and is used for the CMS experiment of the Large Hadron Collider at CERN. DMTCP transparently checkpoints general cluster computations consisting of many nodes, processes, and threads; as well as typical desktop applications. On 128 distributed cores (32 nodes), checkpoint and restart times are typically 2 seconds, with negligible run-time …


Leaching Mechanism Of Semiconducting Minerals, Fathi Habashi Dec 2010

Leaching Mechanism Of Semiconducting Minerals, Fathi Habashi

Fathi Habashi

The mechanism of leaching of semiconducting minerals such as PbS, ZnS, UO2, etc., has been the subject of intensive speculation by hydrometallurgists in the early 1950s. The electrochemical mechanism proposed in 1970 by the author in volume 2 of his Principles of Extractive Metallurgy avoids the assumption of forming intermediate complexes that cannot be isolated or identified.


Problem Niekontrolowanego Spalania Odpadów I Pozostałości Roślinnych W Obszarze Wiejskim Na Wybranym Przykładzie, Robert Oleniacz, Barbara Bacik Nov 2010

Problem Niekontrolowanego Spalania Odpadów I Pozostałości Roślinnych W Obszarze Wiejskim Na Wybranym Przykładzie, Robert Oleniacz, Barbara Bacik

Robert Oleniacz

This paper presents the results of surveys on the problem of uncontrolled burning of waste in domestic stoves and boilers for central heating and open burning of plant residues in rural areas. The questionnaires were conducted among the inhabitants of one of Polish village (Łąkta Dolna), located in the Malopolska province, in the submontane area. The study comprised 80.2% of all households. As is clear from conducted surveys waste were burned in more than 80% of surveyed houses and more than half of respondents admitted to the open burning of plant residues. The percentage of people burning waste and plant …


Wpływ Zakładu Unieszkodliwiania Stałych Odpadów Komunalnych W Warszawie Na Jakość Powietrza, Robert Oleniacz, Jadwiga Antolak Nov 2010

Wpływ Zakładu Unieszkodliwiania Stałych Odpadów Komunalnych W Warszawie Na Jakość Powietrza, Robert Oleniacz, Jadwiga Antolak

Robert Oleniacz

The paper presents the results of air quality impact assessment carried out for the Municipal Solid Waste Disposal Plant in Warsaw. As part of the plant is working so far the only municipal solid waste incinerator in Poland. Following the evaluation, including data for the year 2008, it was found that it is a minor source of emissions to air and causes a slight air pollution. The highest maximum one-hour and annual average concentrations caused at ground level are many times lower than the respective reference (or permissible) values and background values for analyzed substances in the air. Increasing the …


Closing The Gap Between The Industry And Higher Education Institutions- Case Examples From East African Region, Deogratias Harorimana Mr Nov 2010

Closing The Gap Between The Industry And Higher Education Institutions- Case Examples From East African Region, Deogratias Harorimana Mr

Dr Deogratias Harorimana

Much complained about is the quality of graduates Universities put on the labour market. Less talked about however is why knowledge institutions seems to be bad knowledge managers. In this presentation I argue that DIRECT collaborative relationship between Industry,Governments and Higher Education Institutions is a per-requisite.Good relationship is key to building such a successful knowledge transfer strategies between Industries and Educational and Research Institutions. This paper explores what makes a good Knowledge Transfer Partnership Strategy and highlights some key lessons for businesses, Universities and Government bodies. This paper was a Key note presentation to the Annual International Conference on Building …


The Kerf Toolkit For Intrusion Analysis, Javed A. Aslam, Sergey Bratus, David Kotz, Ron Peterson, Brett Tofel, Daniela Rus Nov 2010

The Kerf Toolkit For Intrusion Analysis, Javed A. Aslam, Sergey Bratus, David Kotz, Ron Peterson, Brett Tofel, Daniela Rus

Javed A. Aslam

To aid system administrators with post-attack intrusion analysis, the Kerf toolkit provides an integrated front end and powerful correlation and data-representation tools, all in one package.


Towards Software Health Management With Bayesian Networks, Johann Schumann, Ole J. Mengshoel, Ashok Srivastava, Adnan Darwiche Oct 2010

Towards Software Health Management With Bayesian Networks, Johann Schumann, Ole J. Mengshoel, Ashok Srivastava, Adnan Darwiche

Ole J Mengshoel

More and more systems (e.g., aircraft, machinery, cars) rely heavily on software, which performs safety-critical operations. Assuring software safety though traditional V&V has become a tremendous, if not impossible task, given the growing size and complexity of the software. We propose that iSWHM (Integrated SoftWare Health Management) can increase safety and reliability of high-assurance software systems. iSWHM uses advanced techniques from the area of system health management in order to continuously monitor the behavior of the software during operation, quickly detect anomalies and perform automatic and reliable root-cause analysis, while not replacing traditional V&V. Information provided by the iSWHM system …


Mechanical Properties Of High Blaine Portland Cement, Masoud Rastegar, Kamran Rahmati Shadbad, Ali Hadidi Oct 2010

Mechanical Properties Of High Blaine Portland Cement, Masoud Rastegar, Kamran Rahmati Shadbad, Ali Hadidi

Masoud Rastegar

No abstract provided.


Pomiary Liczby I Wielkości Cząstek Aerozoli W Powietrzu Miejskim Z Wykorzystaniem Metody Optoelektronicznej, Marek Bogacki, Robert Oleniacz, Marian Mazur, Monika Dziugieł Oct 2010

Pomiary Liczby I Wielkości Cząstek Aerozoli W Powietrzu Miejskim Z Wykorzystaniem Metody Optoelektronicznej, Marek Bogacki, Robert Oleniacz, Marian Mazur, Monika Dziugieł

Robert Oleniacz

In the paper some measurement results of number and size for aerosols particles suspended in air achieved using infrared particle sizer IPS-P (Kamika Instruments) with isokinetic air sampling method were presented. In IPS-P analyzer, with measuring range from 0,4 to 300 μm, is applied optical/electronic measurement method which is determined by dimensions of measurement space by aerosols particles motions in a parallel radiation beam. The research was conducted on the roof of four-storey building in Krakow for various meteorological conditions. Results achieved for measured parameters were analysed in terms of selected meteorological factors influence.

English title: Number and size measurements …


Balancing Limiting Factors & Economic Drivers For Sustainable Midwestern Us Agricultural Residue Feedstock Supplies, Wally W. Wilhelm, J. Richard Hess, Douglas L. Karlen, Jane M. F. Johnson, David J. Muth Jr., John M. Baker, Hero T. Gollany, Jeff M. Novak, Diane E. Scott, Gary E. Varvel Oct 2010

Balancing Limiting Factors & Economic Drivers For Sustainable Midwestern Us Agricultural Residue Feedstock Supplies, Wally W. Wilhelm, J. Richard Hess, Douglas L. Karlen, Jane M. F. Johnson, David J. Muth Jr., John M. Baker, Hero T. Gollany, Jeff M. Novak, Diane E. Scott, Gary E. Varvel

David J. Muth

Advanced biofuels will be developed using cellulosic feedstock rather than grain or oilseed crops that can also be used for food and feed. To be sustainable, these new agronomic production systems must be economically viable without degrading the soil and other natural resources. This review examines six agronomic factors that collectively define many of the limits and opportunities for harvesting crop residue for biofuel feedstock in the midwestern United States. The limiting factors include soil organic carbon, wind and water erosion, plant nutrient balance, soil water and temperature dynamics, soil compaction, and off-site environmental impacts. These are discussed in relationship …


A Short-Distance Integral-Balance Solution To A Strong Subdiffusion Equation: A Weak Power-Law Profile, Jordan Hristov Oct 2010

A Short-Distance Integral-Balance Solution To A Strong Subdiffusion Equation: A Weak Power-Law Profile, Jordan Hristov

Jordan Hristov

The work presents an integral solution of the time-fractional subdiffusion through a preliminary defined profile with unknown coefficients and the concept of penetration layer well known from the heat diffusion The profile satisfies the boundary conditions imposed at the boundary of the boundary layer in a weak form that allows its coefficients to be expressed through the boundary layer depth as unique parameter describing the profile. The technique is demonstrated by a solution of a time fractional subdiffusion equation in rectilinear 1-D conditions.


Some Features Of The Concentration Oscillations In The Phenylacetylene Oxidative Carbonylation Reaction (In Russian), Sergey N. Gorodsky Oct 2010

Some Features Of The Concentration Oscillations In The Phenylacetylene Oxidative Carbonylation Reaction (In Russian), Sergey N. Gorodsky

Sergey N. Gorodsky

Some modes of concentration oscillations in the homogeneous system KI-PdI2-CO-O2-CH3OH are described in this paper.


Balancing Limiting Factors & Economic Drivers For Sustainable Midwestern Us Agricultural Residue Feedstock Supplies, Wally W. Wilhelm, J. Richard Hess, Douglas L. Karlen, Jane M. F. Johnson, David J. Muth Jr., John M. Baker, Hero T. Gollany, Jeff M. Novak, Diane E. Scott, Gary E. Varvel Sep 2010

Balancing Limiting Factors & Economic Drivers For Sustainable Midwestern Us Agricultural Residue Feedstock Supplies, Wally W. Wilhelm, J. Richard Hess, Douglas L. Karlen, Jane M. F. Johnson, David J. Muth Jr., John M. Baker, Hero T. Gollany, Jeff M. Novak, Diane E. Scott, Gary E. Varvel

Douglas L Karlen

Advanced biofuels will be developed using cellulosic feedstock rather than grain or oilseed crops that can also be used for food and feed. To be sustainable, these new agronomic production systems must be economically viable without degrading the soil and other natural resources. This review examines six agronomic factors that collectively define many of the limits and opportunities for harvesting crop residue for biofuel feedstock in the midwestern United States. The limiting factors include soil organic carbon, wind and water erosion, plant nutrient balance, soil water and temperature dynamics, soil compaction, and off-site environmental impacts. These are discussed in relationship …


Silver Nanosphere Sers Probes For Sensitive Identification Of Pathogens, Kyuwan Lee Sep 2010

Silver Nanosphere Sers Probes For Sensitive Identification Of Pathogens, Kyuwan Lee

Kyuwan Lee

The identification and timely detection of pathogenic bacteria is critical to ensuring safe food, health, and water. Although surface enhanced Raman scattering (SERS) methods have been used for pathogen characterization and single molecule sensing, the challenge of detecting pathogens in very low numbers using an optimal substrate that is sensitive and reproducible is still a challenge. In this report, we have developed and explored a novel SERS active substrate of 60−80 nm diameter through the assembly of Ag nanocrystals (AgNCs) into Ag nanospheres (AgNSs). A finite difference time domain (FDTD) analysis of the electromagnetic field produced by these structures and …


Product Quality, Perceived Price And Product Features Analysis And Their Influences To Brand Image And Consumer Satisfaction Sep 2010

Product Quality, Perceived Price And Product Features Analysis And Their Influences To Brand Image And Consumer Satisfaction

Homa. P. Harahap

Homa Posniroha Harahap, 2010; Product Quality, Perceived Price and Product Features Analysis and Their Influences to Brand Image and Consumer Satisfaction. Counsellor ; DR. Mohamad Rizan, SE., MM. Generally, the purpose of the research are: 1) Analyzing product quality, perceived price and product features and their influences to brand image and consumer satisfaction, 2) Testing hypothesis on relationship between product quality, perceived price and product features and their influences to brand image and consumer satisfaction,3) Testing hypothesis product quality, perceived price, product features and their direct influences or through brand image to consumer satisfaction. Unit of analysis are mobile phone …


Energetyka Niskoemisyjna, Wojciech M. Budzianowski Sep 2010

Energetyka Niskoemisyjna, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Physical And Chemical Characterization Of Fuel Ethanol Coproducts Relevant To Value-Added Uses, Rumela Bhadra, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan Sep 2010

Physical And Chemical Characterization Of Fuel Ethanol Coproducts Relevant To Value-Added Uses, Rumela Bhadra, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan

Kurt A. Rosentrater

One of the fastest growing industries in the United States is the fuel ethanol industry. In terms of ethanol production capability, the industry has grown by more than 600% since the year 2000. The major coproducts from corn-based ethanol include distillers dried grains with solubles (DDGS) and carbon dioxide. DDGS is used as a livestock feed because it contains high quantities of protein, fiber, amino acids, and other nutrients. The goal of this study was to quantify various chemical and physical properties of DDGS, distillers wet grains (DWG), and distillers dried grain (DDG) from several plants in South Dakota. Chemical …


Product Quality, Perceived Price And Product Features Analysis And Their Influences To Brand Image And Consumer Satisfaction Aug 2010

Product Quality, Perceived Price And Product Features Analysis And Their Influences To Brand Image And Consumer Satisfaction

Benjamin L. Harwood

Homa Posniroha Harahap, 2010; Product Quality, Perceived Price and Product Features Analysis and Their Influences to Brand Image and Consumer Satisfaction. Counsellor ; DR. Mohamad Rizan, SE., MM. Generally, the purpose of the research are: 1) Analyzing product quality, perceived price and product features and their influences to brand image and consumer satisfaction, 2) Testing hypothesis on relationship between product quality, perceived price and product features and their influences to brand image and consumer satisfaction,3) Testing hypothesis product quality, perceived price, product features and their direct influences or through brand image to consumer satisfaction. Unit of analysis are mobile phone …


Lna Based On A Low Cost (~Usd1.30) Commercial Gaas Phemt Mmic Offers Wideband (0.4~1.4 Ghz) And Room-Temperature Low Noise (~0.3 Db) Performances That Satisfy The Ska Low Cost And No-Cooling Requirement, Chin-Leong Lim Aug 2010

Lna Based On A Low Cost (~Usd1.30) Commercial Gaas Phemt Mmic Offers Wideband (0.4~1.4 Ghz) And Room-Temperature Low Noise (~0.3 Db) Performances That Satisfy The Ska Low Cost And No-Cooling Requirement, Chin-Leong Lim

Chin-Leong Lim

Introduction: New generations of radio telescopes such as the Square Kilometre Array consist of millions of receivers scattered over a continent. The array’s quantity and geographic considerations ruled out the traditional radio astronomy LNA implementation; i.e. costly InP devices cooled by high-maintenance closed-cycle helium (He) refrigerators. Several LNA designs have been proposed to address the cost and room-temperature operation constraints but none appear a clear winner. Peltier and package-scale cooling have also been proposed as a lower cost/maintenance alternative to He cooling but when multiplied by the quantity required can still carve a significant chunk of the budget. Additionally, cooling …