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

Physical Sciences and Mathematics Commons

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

2009

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 2551 - 2580 of 7616

Full-Text Articles in Physical Sciences and Mathematics

The First Two Transient Supersoft X-Ray Sources In M31 Globular Clusters And The Connection To Classical Novae, M. Henze, W. Pietsch, F. Haberl, G. Sala, R. Quimby, M. Hernanz, M. Della Valle, P. Milne, G. G. Williams, V Burwitz, J Greiner, H Stiele, Dieter H. Hartmann, A.K.H. Dong, K Hornoch Jun 2009

The First Two Transient Supersoft X-Ray Sources In M31 Globular Clusters And The Connection To Classical Novae, M. Henze, W. Pietsch, F. Haberl, G. Sala, R. Quimby, M. Hernanz, M. Della Valle, P. Milne, G. G. Williams, V Burwitz, J Greiner, H Stiele, Dieter H. Hartmann, A.K.H. Dong, K Hornoch

Publications

Context. Classical novae (CNe) have been found to represent the major class of supersoft X-ray sources (SSSs) in our neighbour galaxy M 31. Aims. We determine the properties and evolution of the two first SSSs ever discovered in the M 31 globular cluster (GC) system. Methods. We have used XMM-Newton, Chandra and Swift observations of the centre region of M 31 to discover both SSSs and to determine their X-ray light curves and spectra. We performed detailed analysis of XMM-Newton EPIC PN spectra of the source in Bol 111 (SS1) using blackbody and NLTE white dwarf (WD) atmosphere models. For …


Software Quality Attribute Measurement And Analysis Based On Class Diagram Metrics, Dalia Rizk Jun 2009

Software Quality Attribute Measurement And Analysis Based On Class Diagram Metrics, Dalia Rizk

Archived Theses and Dissertations

Software quality measurement lies at the heart of the quality engineering process. Quality measurement for object-oriented artifacts has become the key for ensuring high quality software. Both researchers and practitioners are interested in measuring software product quality for improvement. It has recently become more important to consider the quality of products at the early phases, especially at the design level to ensure that the coding and testing would be conducted more quickly and accurately. The research work on measuring quality at the design level progressed in a number of steps. The first step was to discover the correct set of …


Synoptic-Scale Characteristics And Precursors Of Cool-Season Precipitation Events At St. John's, Newfoundland, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum Jun 2009

Synoptic-Scale Characteristics And Precursors Of Cool-Season Precipitation Events At St. John's, Newfoundland, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

The issue of quantitative precipitation forecasting continues to be a significant challenge in operational forecasting, particularly in regions susceptible to frequent and extreme precipitation events. St. John’s, Newfoundland, Canada, is one location affected frequently by such events, particularly in the cool season (October–April). These events can include flooding rains, paralyzing snowfall, and damaging winds.

A precipitation climatology is developed at St. John’s for 1979–2005, based on discrete precipitation events occurring over a time period of up to 48 h. Threshold amounts for three categories of precipitation events (extreme, moderate, and light) are statistically derived and utilized to categorize such events. …


Linking Conformation Change To Hemoglobin Activation Via Chain-Selective Time-Resolved Resonance Raman Spectroscopy On Protoheme/Mesoheme Hybrids, Gurusamy Balakrishnan, Mohammed Ibrahim, Piotr J. Mak, Jessica Hata, James R. Kincaid, Thomas G. Spiro Jun 2009

Linking Conformation Change To Hemoglobin Activation Via Chain-Selective Time-Resolved Resonance Raman Spectroscopy On Protoheme/Mesoheme Hybrids, Gurusamy Balakrishnan, Mohammed Ibrahim, Piotr J. Mak, Jessica Hata, James R. Kincaid, Thomas G. Spiro

Chemistry Faculty Research and Publications

Time-resolved Resonance Raman spectra are reported for Hb tetramers, in which the αand β chains are selectively substituted with mesoheme. The Soret absorption band shift in meso- relative to protoheme permits chain-selective excitation of heme RR spectra. The evolution of these spectra following HbCO photolysis show that geminate recombination rates and yields are the same for the two chains, consistent with recent results on 15N-heme isotopomer hybrids. The spectra also reveal systematic shifts in the deoxy-heme ν4 and νFe-His) RR bands, which are anti-correlated. These shifts are resolved for the successive intermediates in the protein structure, which have previously been …


Simplenpkl: Simple Non-Parametric Kernel Learning, Jinfeng Zhuang, Ivor Tsang, Steven C. H. Hoi Jun 2009

Simplenpkl: Simple Non-Parametric Kernel Learning, Jinfeng Zhuang, Ivor Tsang, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

Previous studies of Non-Parametric Kernel (NPK) learning usually reduce to solving some Semi-Definite Programming (SDP) problem by a standard SDP solver. However, time complexity of standard interior-point SDP solvers could be as high as O(n6.5). Such intensive computation cost prohibits NPK learning applicable to real applications, even for data sets of moderate size. In this paper, we propose an efficient approach to NPK learning from side information, referred to as SimpleNPKL, which can efficiently learn non-parametric kernels from large sets of pairwise constraints. In particular, we show that the proposed SimpleNPKL with linear loss has a closed-form solution that can …


Nonrigid Shape Recovery By Gaussian Process Regression, Jianke Zhu, Steven C. H. Hoi, Michael R. Liu Jun 2009

Nonrigid Shape Recovery By Gaussian Process Regression, Jianke Zhu, Steven C. H. Hoi, Michael R. Liu

Research Collection School Of Computing and Information Systems

Most state-of-the-art nonrigid shape recovery methods usually use explicit deformable mesh models to regularize surface deformation and constrain the search space. These triangulated mesh models heavily relying on the quadratic regularization term are difficult to accurately capture large deformations, such as severe bending. In this paper, we propose a novel Gaussian process regression approach to the nonrigid shape recovery problem, which does not require to involve a predefined triangulated mesh model. By taking advantage of our novel Gaussian process regression formulation together with a robust coarse-to-fine optimization scheme, the proposed method is fully automatic and is able to handle large …


Fisheries Research Report No.157 - The Western Rock Lobster Fishery 2003/2004 And 2004/2005, Simon De Lestang, E H. Barker Jun 2009

Fisheries Research Report No.157 - The Western Rock Lobster Fishery 2003/2004 And 2004/2005, Simon De Lestang, E H. Barker

Fisheries research reports

The 2003/2004 season produced the second highest catch recorded to date (13,684 tonnes), up markedly on the previous season’s catch of 11,415 t. Nominal effort in 2003/2004 (10,180,444 pot lifts) did not vary by nearly as much as did the catch, with total pot lifts declining only slightly (<1%) on the previous season. Season 2004/2005 produced a catch of 12, 236 tonnes, down on the previous season’s catch of 13,684 t. Similar to the catch, total nominal effort in 2004/2005 (9,789,671 pot lifts) also declined fairly substantially (4%) on the previous season. Recreational catches for the above two seasons were also down on their respective previous seasons by 52 and 11% each.

Puerulus settlement coast wide during 2003/2004 was below average, especially towards the southern and northern extremes of the fishery (Port Gregory and Jurien Bay south). This was also the case during the following season (2004/2005), although the poor settlement was more evenly spread across the entire fishery. Catch predictions from these …


Sequence Characterization Of Riordan Arrays, Tian-Xiao He, Renzo Sprugnoli Jun 2009

Sequence Characterization Of Riordan Arrays, Tian-Xiao He, Renzo Sprugnoli

Scholarship

In the realm of the Riordan group, we consider the characterization of Riordan arrays by means of the A- and Z-sequences. It corresponds to a horizontal construction of a Riordan array, whereas the traditional approach is through column generating functions. We show how the A- and Z-sequences of the product of two Riordan arrays are derived from those of the two factors; similar results are obtained for the inverse. We also show how the sequence characterization is applied to construct easily a Riordan array. Finally, we give the characterizations relative to some subgroups of the Riordan group, in particular, of …


Fisheries Research Report No. 193 - Investigating Reproductive Biology Issues Relevant To Managing The Western Rock Lobster Broodstock, Roy Melville-Smith, Simon De Lestang, N Beale, D Groth, A Thompson Jun 2009

Fisheries Research Report No. 193 - Investigating Reproductive Biology Issues Relevant To Managing The Western Rock Lobster Broodstock, Roy Melville-Smith, Simon De Lestang, N Beale, D Groth, A Thompson

Fisheries research reports

Final FRDC Report – Project 2003/005

Objectives:

1. To investigate the implications of the setose and maximum size rules.

2. To undertake preliminary investigations into the implications of egg diameters being significantly smaller at the Abrolhos Islands than at the coast.

3. To quantify the extent of the breeding grounds, so as to weight the overall egg production index for the stock by the contribution of the management zones.

Increases in efficiency due to modern electronic equipment, improved fishing vessels and knowledge about the grounds and lobster behaviour, have all led to western rock lobster fishers becoming more efficient at …


Developing Systems For Cyber Situational Awareness, James. S. Okolica, J. Todd Mcdonald, Gilbert L. Peterson, Robert F. Mills, Michael W. Haas Jun 2009

Developing Systems For Cyber Situational Awareness, James. S. Okolica, J. Todd Mcdonald, Gilbert L. Peterson, Robert F. Mills, Michael W. Haas

Faculty Publications

In both military and commercial settings, the awareness of Cyber attacks and the effect of those attacks on the mission space of an organization has become a targeted information goal for leaders and commanders at all levels. We present in this paper a defining framework to understand situational awareness (SA)—especially as it pertains to the Cyber domain—and propose a methodology for populating the cognitive domain model for this realm based on adversarial knowledge involved with Cyber attacks. We conclude with considerations for developing Cyber SA systems of the future.


Routing In The Dark: Pitch Black, Nathan S. Evans Jun 2009

Routing In The Dark: Pitch Black, Nathan S. Evans

Electronic Theses and Dissertations

In many networks, such as mobile ad-hoc networks and friend-to-friend overlay networks, direct communication between nodes is limited to specific neighbors. Friendto-friend “darknet” networks have been shown to commonly have a small-world topology; while short paths exist between any pair of nodes in small-world networks, it is non-trivial to determine such paths with a distributed algorithm. Recently, Clarke and Sandberg proposed the first decentralized routing algorithm that achieves efficient routing in such small-world networks.

Herein this thesis we discuss the first independent security analysis of Clarke and Sandberg’s routing algorithm. We show that a relatively weak participating adversary can render …


The Burden Of Fetching Water: Using Caloric Expenditure As An Indicator Of Access To Safe Drinking Water—A Case Study From Xieng Khouang Province, Lao Pdr, Jeff La Frenierre Jun 2009

The Burden Of Fetching Water: Using Caloric Expenditure As An Indicator Of Access To Safe Drinking Water—A Case Study From Xieng Khouang Province, Lao Pdr, Jeff La Frenierre

Electronic Theses and Dissertations

The Millennium Development Goals measure ‘access to improved drinking water’ using an indicator that defines access as the presence of an improved water source within 1 kilometer of a person’s dwelling. This purely linear measurement has significant shortcomings, including a lack of consideration for the difficulty of the terrain being traversed and the weight of the loads being carried. This paper examines in detail the human energy costs associated with fetching water, first using two Lao villages as case studies, then applying a predictive energy expenditure model to measure the potential caloric effect of variations in the age and gender …


Probability Density Functions For Snir In Ds-Cdma, David W. Matolak Jun 2009

Probability Density Functions For Snir In Ds-Cdma, David W. Matolak

Faculty Publications

Analytical expressions for the probability density function of block-wise signal-to-noise-plus-interference ratio for both synchronous and asynchronous direct-sequence spread spectrum code-division multiple access systems are developed, for equal average energy signals on the Gaussian and Rayleigh flat fading channels. Using the standard Gaussian approximation for multi-user interference, accurate density approximations are obtained, which agree very well with computer simulation results.


Human Glyoxalase Ii Contains An Fe(Ii)Zn(Ii) Center But Is Active As A Mononuclear Zn(Ii) Enzyme, Pattraranee Limphong, Ross M. Mckinney, Nicole E. Adams, Brian Bennett, Christopher A. Makaroff, Thusitha Gunasekera, Michael W. Crowder Jun 2009

Human Glyoxalase Ii Contains An Fe(Ii)Zn(Ii) Center But Is Active As A Mononuclear Zn(Ii) Enzyme, Pattraranee Limphong, Ross M. Mckinney, Nicole E. Adams, Brian Bennett, Christopher A. Makaroff, Thusitha Gunasekera, Michael W. Crowder

Physics Faculty Research and Publications

Human glyoxalase II (Glx2) was overexpressed in rich medium and in minimal medium containing zinc, iron, or cobalt, and the resulting Glx2 analogues were characterized using metal analyses, steady-state and pre-steady-state kinetics, and NMR and EPR spectroscopies to determine the nature of the metal center in the enzyme. Recombinant human Glx2 tightly binds nearly 1 equiv each of Zn(II) and Fe. In contrast to previous reports, this study demonstrates that an analogue containing 2 equiv of Zn(II) cannot be prepared. EPR studies suggest that most of the iron in recombinant Glx2 is Fe(II). NMR studies show that Fe(II) binds to …


Entanglement Perturbation Theory For Antiferromagnetic Spin Chains, Lihua Wang Jun 2009

Entanglement Perturbation Theory For Antiferromagnetic Spin Chains, Lihua Wang

Dissertations

In this dissertation, we use the recently developed Entanglement Perturbation Theory (EPT) to solve antiferromagnetic spin chain problems, for both spin 1/2 and spin 1. We firs use EPT-g (EPT algorithm for ground state) to get the ground state properties. We calculated precisely energies, magnetization and spin-spin correlations. The precision of the long range spin-spin correlation functions for spin 1/2 chains is unprecedented. Due to its special structure, we also use EPT-g to calculate the firs excited state properties for spin 1 chains. Hence we plotted the phase diagram for spin 1 xxz chains. Also a generalization of EPT (EPT-e) …


Test Procedures For Equality Of Two Variances In Delta Distributions, Jezaniah Kira Sarion Tena Jun 2009

Test Procedures For Equality Of Two Variances In Delta Distributions, Jezaniah Kira Sarion Tena

Dissertations

Statistical literature on testing equality of variances is very broad, encompassing a great number of distributional variations. However, the case of a zero-inflated nonnegative continuous random variable has not yet been considered. Such distribution is specified by a positive probability that the variable assumes a true zero value, together with a conditional distribution for the positive values of the variable.

This study considers the special case, delta distribution, where the positive values come from the lognormal distribution. Test procedures were developed using a statistic based on Gini's Mean Difference. Since the asymptotic distribution of the test statistic was shown to …


Statistical Procedures For Bioequivalence Analysis, Srinand Ponnathapura Nandakumar Jun 2009

Statistical Procedures For Bioequivalence Analysis, Srinand Ponnathapura Nandakumar

Dissertations

Applicants submitting a new drug application (NDA) or new animal drug application (NADA) under the Federal Food, Drug, and Cosmetic Act (FDC Act) are required to document bioavailability (BA). A sponsor of an abbreviated new drug application (ANDA) or abbreviated new animal drug application (ANADA) must document first pharmaceutical equivalence and then bioequivalence (BE) to be deemed therapeutically equivalent to a reference listed drug (RLD). The Average (ABE), Population (PBE) and Individual (IBE) bioequivalence have been used to establish the equivalence in the pharmaco-kinetics of drugs.

The current procedure of PBE uses Cornish Fisher's (CF) expansion on small samples. Since …


(119)Sn Spin-Lattice Relaxation In Alpha-Snf(2), Guenther Neue, Shi Bai, Robert E. Taylor, Peter A. Beckmann, Alexander J. Vega, Cecil Dybowski Jun 2009

(119)Sn Spin-Lattice Relaxation In Alpha-Snf(2), Guenther Neue, Shi Bai, Robert E. Taylor, Peter A. Beckmann, Alexander J. Vega, Cecil Dybowski

Physics Faculty Research and Scholarship

The temperature and magnetic field dependencies of the (119)Sn nuclear spin-lattice relaxation rate in alpha-SnF(2) indicate the presence of two relaxation mechanisms. At temperatures below 350 K, the relaxation is dominated by a nuclear spin-rotation interaction modulated by lattice vibrations, as has been seen for Pb and Tl salts. This (119)Sn relaxation pathway is less effective in SnF(2) than it is for (207)Pb, (203)Tl, and (205)Tl relaxation in some Pb and Tl salts but it is more effective than (111)Cd and (113)Cd relaxation in some Cd salts. Above 350 K, there is an additional contribution to the observed relaxation rate. …


South Burlington Vt: New Urbanist South Village, Jack Kartez, Richard Barringer Jun 2009

South Burlington Vt: New Urbanist South Village, Jack Kartez, Richard Barringer

Planning

The 220 acre master plan for South Village, the largest project in the City of South Burlington’s history, encompasses multiple housing types and innovative provisions for affordable housing. It integrates housing with open space and natural resource conservation, including a major Community Supported Agriculture project developed by a nonprofit partner, the Intervale Foundation. While not a mixed-use project (that is, commercial as well as residential development), South Village nonetheless represents a qualitative change in approach for South Burlington by incorporating large-scale open space preservation as part of development and multiple housing-types in one project. The case study recounts events leading …


Simple Fit Of Data Relating Supermassive Black Hole Mass To Galaxy Pitch Angle, Harry I. Ringermacher, Lawrence R. Mead Jun 2009

Simple Fit Of Data Relating Supermassive Black Hole Mass To Galaxy Pitch Angle, Harry I. Ringermacher, Lawrence R. Mead

Faculty Publications

Seigar et al. have recently demonstrated a new, tight correlation between galactic central supermassive black hole (BH) mass and the pitch angle of the spiral arm in disk galaxies which they attribute to other indirect correlations. They fit a double power law, governed by five parameters, to the BH mass as a function of pitch. Noting the features of their fitted curve, we show that a simple linear proportion of the BH mass to the cotangent of the pitch angle can obtain the same fit, within error. Such a direct, elegant fit may help shed light on the nature of …


Enhancing Ocean Literacy Using Real-Time Data, Lisa G. Adams, George Matsumoto Jun 2009

Enhancing Ocean Literacy Using Real-Time Data, Lisa G. Adams, George Matsumoto

Faculty Articles

No abstract provided.


Surface Reconstruction Through Time, Leeann T. Brash Jun 2009

Surface Reconstruction Through Time, Leeann T. Brash

Dartmouth College Master’s Theses

Surface reconstruction is an area of computational geometry that has been progressing rapidly over the last decade. Current algorithms and their implementations can reconstruct surfaces from a variety of input and the accuracy and precision improve with each new development. These all make use of various heuristics to achieve a reconstruction. Much of this work consists of reconstructing a still object from point samples taken from the object's surface. We examine reconstructing an n-dimensional object and its motion by treating time as an (n + 1)st axis. Our input consists of (n-1)-dimensional scans taken over time and at di?erent positions …


Mnte-2-Pyp And Radiation In A Prostate Cancer Model: Implications For Radiotherapy, Adeola Y. Makinde Jun 2009

Mnte-2-Pyp And Radiation In A Prostate Cancer Model: Implications For Radiotherapy, Adeola Y. Makinde

Loma Linda University Electronic Theses, Dissertations & Projects

A major limitation of successful radiation therapy in cancer treatment is the increase in normal tissue damage as higher doses are used to achieve greater tumor destruction. Radiation dose optimization in cancer therapy requires achieving maximum tumor destruction with minimal damage to normal tissue Antioxidants have been shown to protect normal tissues against radiation damage, as radiation-induced tissue damage results predominantly from reactive oxygen species that directly damage cellular components. However, for effective use as normal tissue radioprotectants in radiotherapy, these antioxidants must not protect the tumors. Mn (III) tetrakis (N-ethylpyridinium-2-yl) porphyrin (MnTE-2-PyP) is a metalloporphyrin antioxidant that has been …


Information Sharing And Strategic Signaling In Supply Chains, Robert J. Kauffman, Hamid Mohtadi Jun 2009

Information Sharing And Strategic Signaling In Supply Chains, Robert J. Kauffman, Hamid Mohtadi

Research Collection School Of Computing and Information Systems

Information sharing in procurement occurs in rich and varied industry contexts in which managerial decisions are made and organizational strategy is formulated. We explore how information sharing ought to work in procurement contexts that involve investments in inter-organizational information systems (IOS) and collaborative planning, forecasting and replenishment (CPFR) practices. How and under what circumstances does a firm that plays the role of a supply chain buyer decide to share information on key variables, such as point-of-sale consumer demand data with its supplier, up the supply chain? This is a key issue that crosses the boundary between supply chain management and …


Non-Redundant Sequential Rules - Theory And Algorithm, David Lo, Siau-Cheng Khoo, Limsoon Wong Jun 2009

Non-Redundant Sequential Rules - Theory And Algorithm, David Lo, Siau-Cheng Khoo, Limsoon Wong

Research Collection School Of Computing and Information Systems

A sequential rule expresses a relationship between two series of events happening one after another. Sequential rules are potentially useful for analyzing data in sequential format, ranging from purchase histories, network logs and program execution traces. In this work, we investigate and propose a syntactic characterization of a non-redundant set of sequential rules built upon past work on compact set of representative patterns. A rule is redundant if it can be inferred from another rule having the same support and confidence. When using the set of mined rules as a composite filter, replacing a full set of rules with a …


Operational Verification Of A Relativistic Program, Robert T. Bauer Jun 2009

Operational Verification Of A Relativistic Program, Robert T. Bauer

Computer Science Faculty Publications and Presentations

Engineering eorts to achieve scalable multiprocessor perfor- mance for concurrent reader-writer programs have resulted in a family of algorithms that are non-blocking and that tolerate interprocessor in- terference. Because these algorithms accept a unique frame of reference for each processor's accesses to memory, they typify a concurrent pro- gramming technique for shared memory multicore architectures called relativistic programmming.

Rigorous verification of these algorithms is not possible with existing semantic based approaches because the semantics under approximates multiprocessor behavior and the algorithms rely on abstruse interactions with the operating system that aren't reconciled with language seman- tics.

The Read-Copy Update (RCU) …


Interference-Aware Routing Protocol In Multi-Radio Wireless Mesh Networks, Byoungheon Shin, Yangwoo Ko, Jisun An, Dongman Lee Jun 2009

Interference-Aware Routing Protocol In Multi-Radio Wireless Mesh Networks, Byoungheon Shin, Yangwoo Ko, Jisun An, Dongman Lee

Research Collection School Of Computing and Information Systems

Utilization of multiple radio interfaces increases throughput of wireless networks. Existing work proposes a multi-radio routing protocol exploiting link quality and channel diversity of a path. While an established path is deteriorated by interferences incurred by any changes in a network, and existing work does not detect the deterioration. In this paper, we propose an interference-aware multi-radio routing protocol detecting and resolving dynamic path deterioration in wireless mesh networks.


Adaptive In-Network Processing For Bandwidth And Energy Constrained Mission-Oriented Multi-Hop Wireless Networks, Sharanya Eswaran, Matthew Johnson, Archan Misra, Thomas La Porta Jun 2009

Adaptive In-Network Processing For Bandwidth And Energy Constrained Mission-Oriented Multi-Hop Wireless Networks, Sharanya Eswaran, Matthew Johnson, Archan Misra, Thomas La Porta

Research Collection School Of Computing and Information Systems

In-network processing, involving operations such as filtering, compression and fusion, is widely used in sensor networks to reduce the communication overhead. In many tactical and stream-oriented wireless network applications, both link bandwidth and node energy are critically constrained resources and in-network processing itself imposes non-negligible computing cost. In this work, we have developed a unified and distributed closed-loop control framework that computes both a) the optimal level of sensor stream compression performed by a forwarding node, and b) the best set of nodes where the stream processing operators should be deployed. Our framework extends the Network Utility Maximization (NUM) paradigm, …


Pressure-Driven Transport Of Particles Through A Converging-Diverging Microchannel, Ye Ai, Sang W. Joo, Yingtao Jiang, Xiangchun Xuan, Shizhi Qian Jun 2009

Pressure-Driven Transport Of Particles Through A Converging-Diverging Microchannel, Ye Ai, Sang W. Joo, Yingtao Jiang, Xiangchun Xuan, Shizhi Qian

Mechanical Engineering Faculty Research

Pressure-driven transport of particles through a symmetric converging-diverging microchannel is studied by solving a coupled nonlinear system, which is composed of the Navier–Stokes and continuity equations using the arbitrary Lagrangian–Eulerian finite-element technique. The predicted particle translation is in good agreement with existing experimental observations. The effects of pressure gradient, particle size, channel geometry, and a particle’s initial location on the particle transport are investigated. The pressure gradient has no effect on the ratio of the translational velocity of particles through a converging-diverging channel to that in the upstream straight channel. Particles are generally accelerated in the converging region and then …


Finite Sample Properties Of Minimum Kolmogorov-Smirnov Estimator And Maximum Likelihood Estimator For Right-Censored Data, Jerzy Wieczorek Jun 2009

Finite Sample Properties Of Minimum Kolmogorov-Smirnov Estimator And Maximum Likelihood Estimator For Right-Censored Data, Jerzy Wieczorek

Dissertations and Theses

MKSFitter computes minimum Kolmogorov-Smirnov estimators (MKSEs) for several different continuous univariate distributions, using an evolutionary optimization algorithm, and recommends the distribution and parameter estimates that best minimize the Kolmogorov-Smirnov (K-S) test statistic. We modify this tool by extending it to use the Kaplan-Meier estimate of the cumulative distribution function (CDF) for right-censored data. Using simulated data from the most commonly-used survival distributions, we demonstrate the tool's inability to consistently select the correct distribution type with right-censored data, even for large sample sizes and low censoring rates. We also compare this tool's estimates with the right-censored maximum likelihood estimator (MLE). While …