Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2005

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1621 - 1650 of 5573

Full-Text Articles in Physical Sciences and Mathematics

Dream: A Theoretical Analysis, Xueying Qi Jul 2005

Dream: A Theoretical Analysis, Xueying Qi

Computer Science Theses & Dissertations

A Mobile Ad-hoc Network (MANET, for short) is a collection of mobile nodes deployed in support of a short-lived special-purpose operation. Examples include search-and-rescue missions, law-enforcement, multimedia classrooms, and among many others. Unlike cellular or satellite networks, MANET do not rely on any form of pre-existing infrastructure. The mobility of nodes combined with the lack of infrastructure makes routing in MANET notoriously difficult. It was recently suggested that routing in MANET can use to advantage geographic information that the nodes may acquire either by endowing them with a GPS chip or simply by using known localization algorithms. Distance Routing Effect …

Go to article

Mobility-Pattern Based Localization Update Algorithm For Mobile Wireless Sensor Networks, Mohammad Yacoub Al-Laho Jul 2005

Mobility-Pattern Based Localization Update Algorithm For Mobile Wireless Sensor Networks, Mohammad Yacoub Al-Laho

Electrical & Computer Engineering Theses & Dissertations

In mobile wireless sensor networks, sensors move in the monitored area at any direction and speed. Unlike many other networking hosts, sensor nodes do not have global addresses. They are often identified by using a location-based addressing scheme. Therefore, it is important to have the knowledge of the sensor location indicating where the data came from. In this thesis, three localization update algorithms were designed, Specifically, a sensor movement is divided into three states: Pause, Linear, and Random. Each state adopts different localization update algorithm. Since complex movement involves different mobility patterns, a state transition model is developed to …

Go to article

Modeling The Effects Of Physical And Biogeochemical Processes On Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean, Baris Salihoglu Jul 2005

Modeling The Effects Of Physical And Biogeochemical Processes On Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean, Baris Salihoglu

OES Theses and Dissertations

The primary objective of this research is to investigate phytoplankton community response to variations in physical forcing and biological processes in the Cold Tongue region of the equatorial Pacific Ocean at 0°N, 140°W. This research objective was addressed using a one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology, such as spectrally-dependent photosynthetic processes and iron limitation on algal growth. The ecosystem model is forced by a one-year (1992) time series of spectrally-dependent light, temperature, and water column mixing obtained from a Tropical Atmosphere-Ocean (TAO) Array mooring. Autotrophic growth is represented by five algal groups, which have …

Go to article

Investigation Of The Superconducting Properties Of Niobium Radio-Frequency Cavities, Gianluigi Ciovati Jul 2005

Investigation Of The Superconducting Properties Of Niobium Radio-Frequency Cavities, Gianluigi Ciovati

Physics Theses & Dissertations

Radio-frequency (rf) superconducting cavities are widely used to increase the energy of a charged particle beam in particle accelerators. The maximum gradients of cavities made of bulk niobium have constantly improved over the last ten years and they are approaching the theoretical limit of the material. Nevertheless, rf tests of niobium cavities are still showing some "anomalous" losses (so-called "Q-drop"), characterized by a marked increase of the surface resistance at high rf fields, in absence of field emission. A low temperature "in-situ" baking under ultra-high vacuum has been successfully applied by several laboratories to reduce those losses and …

Go to article

Principal Component Regression For Construction Of Wing Weight Estimation Models, Humberto Rocha Jul 2005

Principal Component Regression For Construction Of Wing Weight Estimation Models, Humberto Rocha

Mathematics & Statistics Theses & Dissertations

The multivariate data fitting problem occurs frequently in many branches of science and engineering. It is very easy to fit a data set exactly by a mathematical model no matter how the data points are distributed. But building a response by using a limited number of poorly distributed data points is very unreliable, yet necessary in conceptual design process. This thesis documents the lessons learned from fitting the wing weight data of 41 subsonic transports by three types of interpolation methods---least polynomial interpolation, radial basis function interpolation, and Kriging interpolation. The objective of this thesis is to develop an automatic …

Go to article

Radiative Neutron Β-Decay In Effective Field Theory, Susan Gardner, Véronique Bernard, Chi Zhang Jul 2005

Radiative Neutron Β-Decay In Effective Field Theory, Susan Gardner, Véronique Bernard, Chi Zhang

School of Biological Sciences: Faculty Publications

We consider radiative β-decay of the neutron in heavy baryon chiral perturbation theory. Nucleon-structure effects not encoded in the weak coupling constants gA and gV are determined at next-to-leading order in the chiral expansion, and enter at the O(0.5%)-level, making a sensitive test of the Dirac structure of the weak currents possible.

Go to article

Statistical Analysis Of Rock Fabrics, Boris Avdeev Jul 2005

Statistical Analysis Of Rock Fabrics, Boris Avdeev

Earth & Environmental Sciences Theses

The main goal of the work is to present new procedures for statistical analysis of fabric data for structural geology. After an introduction to the problems of orientation analysis, discussion of different types of the orientation data and a brief review of the existing techniques and statistics for the orientation data, a comprehensive discussion of several proposed methods is given. The first part of the methodology chapter states a general model in terms of a structural frame and introduces some notation. The second part is a detailed description of a pooled estimator, which is intended to assess a structural frame …

Go to article

A First-Principles Study On Bulk Cuo: Electronic Structures And Native Point Defects, Dangxin Wu Jul 2005

A First-Principles Study On Bulk Cuo: Electronic Structures And Native Point Defects, Dangxin Wu

Physics Theses

In this thesis, we have performed a first-principles study on strongly correlated monoclinic cupric oxide (CuO) by using the LSDA+U method implemented in the PAW method. Based on the optimized structural parameters, which are in good agreement with the experimental data, the electronic structure and the magnetic properties are obtained. Our calculations show that CuO is a semiconducting material with an indirect gap of about 1.0 eV. The semiconducting nature of CuO from our calculations is consistent with many experiments, but is qualitatively different from the LSDA calculations which incorrectly predict CuO to be metallic. The indirect gap of 1.0 …

Go to article

A Sensor Fusion Approach To Coastal Mapping, Maryellen Sault, Christopher Parrish, Stephen A. White, Jon Sellars, Jason Woolard Jul 2005

A Sensor Fusion Approach To Coastal Mapping, Maryellen Sault, Christopher Parrish, Stephen A. White, Jon Sellars, Jason Woolard

Center for Coastal and Ocean Mapping

NOAA’s National Geodetic Survey (NGS) is responsible for mapping the national shoreline. This shoreline provides the critical baseline for demarcating the United States’ marine territorial limits, including its Exclusive Economic Zone; and is used in updating NOAA nautical charts and management of coastal resourses. NGS conducted a data fusion research project in collaboration with the Joint Airborne Lidar Bathymetric Technical Center of Expertise (JALBTCX) and other NOAA partners. In March and April of 2004, hyperspectral imagery, topographic lidar data, and highresolution digital color imagery were collected simultaneously aboard the NOAA Citation for coastal project areas in Florida and California. The …

Go to article

Charge Transfer In Slow Collisions Of C⁶⁺ With H Below 1 Kev / Amu, Chen-Nan Liu, Shu-Chun Cheng, Anh-Thu Le, C. D. Lin Jul 2005

Charge Transfer In Slow Collisions Of C⁶⁺ With H Below 1 Kev / Amu, Chen-Nan Liu, Shu-Chun Cheng, Anh-Thu Le, C. D. Lin

Physics Faculty Research & Creative Works

We reexamine the charge transfer cross sections for C⁶⁺ + H collisions for energies below 1 keV / amu using a fully quantum mechanical approach, based on the hyperspherical close-coupling method. Whereas most previous theoretical and experimental data agree well for the dominant charge transfer to the C⁵⁺(n=4) states, there is significant disagreement among the theories for the transition to the weaker n=5 states. Using the present quantum mechanical calculations we analyze the origin of the discrepancy among these previous calculations. We further extend the calculations to collision energies down to about 1 eV and show that electron capture to …

Go to article

Calculation Of Hydrogenic Bethe Logarithms For Rydberg States, Ulrich D. Jentschura, Peter J. Mohr Jul 2005

Calculation Of Hydrogenic Bethe Logarithms For Rydberg States, Ulrich D. Jentschura, Peter J. Mohr

Physics Faculty Research & Creative Works

We describe the calculation of hydrogenic (one-loop) Bethe logarithms for all states with principal quantum numbers 200. While, in principle, the calculation of the Bethe logarithm is a rather easy computational problem involving only the nonrelativistic (Schrdinger) theory of the hydrogen atom, certain calculational difficulties affect highly excited states, and in particular states for which the principal quantum number is much larger than the orbital angular momentum quantum number. Two evaluation methods are contrasted. One of these is based on the calculation of the principal value of a specific integral over a virtual photon energy. The other method relies directly …

Go to article

The Appearance, Apparent Speed, And Removal Of Optical Effects For Relativistically Moving Objects, Robert J. Deissler Jul 2005

The Appearance, Apparent Speed, And Removal Of Optical Effects For Relativistically Moving Objects, Robert J. Deissler

Physics Faculty Publications

Because various parts of an object are different distances from an observer, and light takes a finite time to reach the observer, the appearance of a relativistically moving object will be very different from that given by the Lorentz contraction. We derive equations that can be applied to a photographic image so that the Lorentz contraction can still be observed. We also give equations that quantify the apparent deformation of the object and plots that show the apparent speed of the object as a function of time. In particular, as an object approaches, its apparent speed can be much greater …

Go to article

An Nlo Qcd Analysis Of Inclusive Cross-Section And Jet-Production Fata From The Zeus Experiment, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini Jul 2005

An Nlo Qcd Analysis Of Inclusive Cross-Section And Jet-Production Fata From The Zeus Experiment, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini

Faculty Publications

The ZEUS inclusive differential cross-section data from HERA, for charged and neutral current processes taken with e + and e - beams, together with differential cross-section data on inclusive jet production in e + p scattering and dijet production in γp scattering, have been used in a new NLO QCD analysis to extract the parton distribution functions of the proton. The input of jet-production data constrains the gluon and allows an accurate extraction of alpha s(MZ) at NLO; alphas = 0.1183±0.0028(exp.)±0.0008(model). An additional uncertainty from the choice of scales is estimated as ±0.005. This is the first extraction of alphas(MZ) …

Go to article

แนะนำโครงการสถาบันวิจัยสภาวะแวดล้อม : โครงการศึกษาและกำหนดดัชนีชี้วัด มาตรฐานคุณภาพแหล่งท่องเที่ยวเชิงนิเทศ, กองบรรณาธิการ Jul 2005

แนะนำโครงการสถาบันวิจัยสภาวะแวดล้อม : โครงการศึกษาและกำหนดดัชนีชี้วัด มาตรฐานคุณภาพแหล่งท่องเที่ยวเชิงนิเทศ, กองบรรณาธิการ

Thai Environment

No abstract provided.

Go to article

สรุปข่าว & กิจกรรมสิ่งแวดล้อม Jul 2005

สรุปข่าว & กิจกรรมสิ่งแวดล้อม

Thai Environment

No abstract provided.

Go to article

เมืองเขียวสดใสรวมใจวางแผนเพื่อโลก, กองบรรณาธิการ Jul 2005

เมืองเขียวสดใสรวมใจวางแผนเพื่อโลก, กองบรรณาธิการ

Thai Environment

No abstract provided.

Go to article

ผลกระทบจากเหตุธรณีพิบัติ (Tsunami) ต่อทรัพยากรทางทะเลและชายฝั่งทะเลอันดามัน, ปริทัศน์ เจริญสิทธิ์ Jul 2005

ผลกระทบจากเหตุธรณีพิบัติ (Tsunami) ต่อทรัพยากรทางทะเลและชายฝั่งทะเลอันดามัน, ปริทัศน์ เจริญสิทธิ์

Thai Environment

No abstract provided.

Go to article

พลังงานจากขยะ : กรณีศึกษา ความสำเร็จจากการผสมผสาน กระบวนการมีส่วนร่วมของประชาชนกับเทคโนโลยีของเทศบาลเมืองระยอง, ธีรพล คังคะเกตุ Jul 2005

พลังงานจากขยะ : กรณีศึกษา ความสำเร็จจากการผสมผสาน กระบวนการมีส่วนร่วมของประชาชนกับเทคโนโลยีของเทศบาลเมืองระยอง, ธีรพล คังคะเกตุ

Thai Environment

No abstract provided.

Go to article

การจัดการคุณภาพอากาศในประเทศไทย, นพภาพร พานิช Jul 2005

การจัดการคุณภาพอากาศในประเทศไทย, นพภาพร พานิช

Thai Environment

No abstract provided.

Go to article

นโยบายและแนวทางการจัดการขยะมูลฝอยชุมชน, มัธยา รักษาสัตย์ Jul 2005

นโยบายและแนวทางการจัดการขยะมูลฝอยชุมชน, มัธยา รักษาสัตย์

Thai Environment

No abstract provided.

Go to article

การวิเคราะห์ศักยภาพพื้นที่เพื่อการท่องเที่ยวเชิงนิเวศ, ระหัตร โรจนประดิษฐ์ Jul 2005

การวิเคราะห์ศักยภาพพื้นที่เพื่อการท่องเที่ยวเชิงนิเวศ, ระหัตร โรจนประดิษฐ์

Thai Environment

No abstract provided.

Go to article

เส้นทางการสะสมสารมลพิษตกค้างยาวนาน ในห่วงโซ่อาหารของเนื้อ/นมโค, เบญจลักษณ์ กาญจนเศรษฐ์ Jul 2005

เส้นทางการสะสมสารมลพิษตกค้างยาวนาน ในห่วงโซ่อาหารของเนื้อ/นมโค, เบญจลักษณ์ กาญจนเศรษฐ์

Thai Environment

No abstract provided.

Go to article

กิจกรรมการทดสอบความชำนาญ (Proficiency Testing) ห้องปฏิบัติการสถาบันวิจัยสภาวะแวดล้อมจุฬาฯ, วลีพร ศรีเพ็ญประภา Jul 2005

กิจกรรมการทดสอบความชำนาญ (Proficiency Testing) ห้องปฏิบัติการสถาบันวิจัยสภาวะแวดล้อมจุฬาฯ, วลีพร ศรีเพ็ญประภา

Thai Environment

No abstract provided.

Go to article

วาระแห่งกรุงเทพมหานคร (Bangkok Agenda 21), สุพัตรา วิเศษสุข Jul 2005

วาระแห่งกรุงเทพมหานคร (Bangkok Agenda 21), สุพัตรา วิเศษสุข

Thai Environment

No abstract provided.

Go to article

สิ่งแวดล้อมน่ารู้, สิริพร แก่นสียา Jul 2005

สิ่งแวดล้อมน่ารู้, สิริพร แก่นสียา

Thai Environment

No abstract provided.

Go to article

สร้างโลกสวย, สิริพร แก่นสียา Jul 2005

สร้างโลกสวย, สิริพร แก่นสียา

Thai Environment

No abstract provided.

Go to article

Deposit-Case Attack Against Secure Roaming, Guomin Yang, Duncan S. Wong, Xiaotie Deng Jul 2005

Deposit-Case Attack Against Secure Roaming, Guomin Yang, Duncan S. Wong, Xiaotie Deng

Research Collection School Of Computing and Information Systems

A secure roaming protocol involves three parties: a roaming user, a visiting foreign server and the user’s home server. The protocol allows the user and the foreign server to establish a session key and carry out mutual authentication with the help of the home server. In the mutual authentication, user authentication is generally done in two steps. First, the user claims that a particular server is his home server. Second, that particular server is called in by the foreign server for providing a ‘credential’ which testifies the user’s claim. We present a new attacking technique which allows a malicious server …

Go to article

Emd-Based Video Clip Retrieval By Many-To-Many Matching, Yuxin Peng, Chong-Wah Ngo Jul 2005

Emd-Based Video Clip Retrieval By Many-To-Many Matching, Yuxin Peng, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper presents a new approach for video clip retrieval based on Earth Mover's Distance (EMD). Instead of imposing one-to-one matching constraint as in [11, 14], our approach allows many-to-many matching methodology and is capable of tolerating errors due to video partitioning and various video editing effects. We formulate clip-based retrieval as a graph matching problem in two stages. In the first stage, to allow the matching between a query and a long video, an online clip segmentation algorithm is employed to rapidly locate candidate clips for similarity measure. In the second stage, a weighted graph is constructed to model …

Go to article

Co-Clustering Of Time-Evolving News Story With Transcript And Keyframe, Xiao Wu, Chong-Wah Ngo, Qing Li Jul 2005

Co-Clustering Of Time-Evolving News Story With Transcript And Keyframe, Xiao Wu, Chong-Wah Ngo, Qing Li

Research Collection School Of Computing and Information Systems

This paper presents techniques in clustering the same-topic news stories according to event themes. We model the relationship of stories with textual and visual concepts under the representation of bipartite graph. The textual and visual concepts are extracted respectively from speech transcripts and keyframes. Co-clustering algorithm is employed to exploit the duality of stories and textual-visual concepts based on spectral graph partitioning. Experimental results on TRECVID-2004 corpus show that the co-clustering of news stories with textual-visual concepts is significantly better than the co-clustering with either textual or visual concept alone.

Go to article

Exploiting Belief Bounds: Practical Pomdps For Personal Assistant Agents, Pradeep Varakantham, Rajiv Maheswaran, Milind Tambe Jul 2005

Exploiting Belief Bounds: Practical Pomdps For Personal Assistant Agents, Pradeep Varakantham, Rajiv Maheswaran, Milind Tambe

Research Collection School Of Computing and Information Systems

Agents or agent teams deployed to assist humans often face the challenges of monitoring the state of key processes in their environment (including the state of their human users themselves) and making periodic decisions based on such monitoring. POMDPs appear well suited to enable agents to address these challenges, given the uncertain environment and cost of actions, but optimal policy generation for POMDPs is computationally expensive. This paper introduces three key techniques to speedup POMDP policy generation that exploit the notion of progress or dynamics in personal assistant domains. Policy computation is restricted to the belief space polytope that remains …

Go to article

First Prev Next Last