Physical Sciences and Mathematics Commons^™

Accounting For Missing Data In End-Of-Life Research, Paula Diehr, Laura Lee Johnson

Paula Diehr

End-of-life studies are likely to have missing data because sicker persons are less likely to provide information and because measurements cannot be made after death. Ignoring missing data may result in data that are too favorable, because the sickest persons are effectively dropped from the analysis. In a comparison of two groups, the group with the most deaths and missing data will tend to have the most favorable data, which is not desirable. Results based on only the available data may not be generalizable to the original study population. If most of the missing data are absent because of death, …

Kinetic Theory Of Random Graphs: From Paths To Cycles, E. Ben-Naim, P.L. Krapivsky

Eli Ben-Naim

Structural properties of evolving random graphs are investigated. Treating linking as a dynamic aggregation process, rate equations for the distribution of node to node distances (paths) and of cycles are formulated and solved analytically. At the gelation point, the typical length of paths and cycles, l, scales with the component size k as l ~ k^{1/2}. Dynamic and finite-size scaling laws for the behavior at and near the gelation point are obtained. Finite-size scaling laws are verified using numerical simulations.

Gradient Directed Regularization For Sparse Gaussian Concentration Graphs, With Applications To Inference Of Genetic Networks, Hongzhe Li, Jiang Gui

UPenn Biostatistics Working Papers

Large-scale microarray gene expression data provide the possibility of constructing genetic networks or biological pathways. Gaussian graphical models have been suggested to provide an effective method for constructing such genetic networks. However, most of the available methods for constructing Gaussian graphs do not account for the sparsity of the networks and are computationally more demanding or infeasible, especially in the settings of high-dimension and low sample size. We introduce a threshold gradient descent regularization procedure for estimating the sparse precision matrix in the setting of Gaussian graphical models and demonstrate its application to identifying genetic networks. Such a procedure is …

11,12-Bis(2,2-Dimethyl­Prop­Yl)-9,10-Dihydro-9,10-Ethenoanthracene, Joseph P. Herres, Mark A. Forman, Kraig A. Wheeler

Kraig A. Wheeler

The title compound, C26H32, was retrieved as one of three products from the reaction of tert-butyl­lithium with 11,12-dimethyl­ene-9,10-dihydro­ethenoanthracene and 4,5-diiodo­penta­cyclo­[4.3.0.02,4.03,8.05,7]nonane. The structure shows the expected ethenoanthracene geometry with mol­ecules arranged via van der Waals surfaces.

From Tapes To Bits: The Changing Landscape Of Broadcasting, Veronika M. Megler, Luis Estrada

Veronika M. Megler

For more than a decade, IBM has been a leader in digital media technology, helping broadcast companies worldwide transition from analog to digital environments with a full slate of end-to-end solutions and services. This white paper discusses the evolution of the digital production environment in broadcasting, why the central storage-based model is outperforming other business models as the option of choice, and how to design and implement a scalable digital media infrastructure using IBM technology that simplifies digital video sharing and management. The IT-based infrastructure for broadcast production is particularly valuable as broadcasters transition to high-definition video production, where their …

54th Spsj Annual Meeting Yokohama, Japan, May 25-27, 2005, Jane C. Vogl, Hiroyuki Ohno

Otto Vogl

No abstract provided.

On The Existence Of Multiple Periodic Solutions For The Vector P-Laplacian Via Critical Point Theory, Haishen Lu, Donal O'Regan, Ravi P. Agarwal

Mathematics and System Engineering Faculty Publications

We study the vector p-Laplacian (∗){−(|u′|p−2u′)′=∇F(t,u)a.e.t∈[0,T],u(0)=u(T),u′(0)=u′(T),1

Investigation Of Egocentric And Exocentric Distance Perception In Virtual Environments: Application To Enhance Transfer Of Training In Multi-Model Ves, Cali Fidopiastis

Link Foundation Modeling, Simulation and Training Fellowship Reports

In this report we summarize the results for three experiments completed during the Link Fellowship period. The aim of the first and second experiments were to test the efficacy of a novel assessment procedure for determining visual acuity and quantifying depth errors of observers wearing an optical see-t1u·ough prototype head-mounted display. If successful, the assessments could provide an optimization procedure capable of discerning limitations attributed to separate components of the VE system or to the system as a whole. The second experiment explored the feasibility of utilizing mixed reality (a mix of real and virtual items) environments for the study …

The Relationship Between The Number Of Shots And The Quality Of Gamma Knife Radiosurgeries, D Cheek, Allen G. Holder, M Fuss, B Salter

Mathematics Faculty Research

Radiosurgery is a non-invasive alternative to brain surgery that uses a single focused application of high radiation to destroy intracerebral target tissues. A Gamma Knife delivers such treatments by using 201 cylindrically collimated cobalt-60 sources that are arranged in a hemispherical pattern and aimed to a common focal point. The accumulation of radiation at the focal point, called a \shot" due to the spherical nature of the dose distribution, is used to ablate (or destroy) target tissue in the brain. If the target is small and spherical, it is easily treated by choosing one of four available collimators (4, 8, …

Loss Aware Rate Allocations In H.263 Coded Video Transmissions, Xiao Su, Benjamin Wah

Faculty Publications

For packet video, information loss and bandwidth limitation are two factors that affect video playback quality. Traditional rate allocation approaches have focused on optimizing video quality under bandwidth constraint alone. However, in the best-effort Internet, packets carrying video data are susceptible to losses, which need to be reconstructed at the receiver side. In this paper, we propose loss aware rate allocations in both group-of-block (GOB) level and macroblock level, given that certain packets are lost during transmissions and reconstructed using simple interpolation methods at the receiver side. Experimental results show that our proposed algorithms can produce videos of higher quality …

Enterprise Systems Manager, Edward Aractingi

IT Research

Presentation on the need of remote systems administration.

Isobaric Analog States As A Tool For Spectroscopy Of Exotic Nuclei, G. V. Rogachev, A. A. Aprahamian, F. D. Becchetti, P. Boutachkov, Y. Chen, G. Chubarian, P. A. Deyoung, A. Fomichev, V. Z. Goldberg, M. S. Golovkov, J. J. Kolata, Yu. Ts. Oganessian, Graham F. Peaslee, M. Quinn, A. Rodin, B. B. Skorodumov, R. S. Slepnev, G. Ter-Akopian, W. H. Trzaska, A. Wohr, R. Wolski

Faculty Publications

Spectroscopy of neutron rich exotic isotopes via their isobaric analog states (IAS) in less exotic nuclei is discussed. Several different experimental techniques, which can be applied to search for IAS of exotic isotopes, are described. Successful application of these techniques to the studies of heavy helium isotopes7He and 9He led to the observation of unknown IAS in 7Li and 9Li. Spectroscopic information for these states were obtained, and implication of these findings to the structure of 7,9He is considered.

A Combined Routing Method For Ad Hoc Wireless Networks, Zhenhui Jiang

Dartmouth College Master’s Theses

To make ad hoc wireless networks adaptive to different mobility and traffic patterns, we studied in this thesis an approach to swap from one protocol to another protocol dynamically, while routing continues. By the insertion of a new layer, we were able to make each node in the ad hoc wireless network notify each other about the protocol swap. To ensure that routing works efficiently after the protocol swap, we initialized the destination routing protocol's data structures and reused the previous routing information to build the new routing table. We also tested our approach under different network topologies and traffic …

A Steerable, Untethered, 250x60 Micron Mems Mobile Micro-Robot, Bruce R. Donald, Christopher G. Levey, Craig D. Mcgray, Igor Paprotny, Daniela Rus

Computer Science Technical Reports

We present a steerable, electrostatic, untethered, MEMS micro-robot, with dimensions of 60 µm by 250 µm by 10 µm. This micro-robot is 1 to 2 orders of magnitude smaller in size than previous micro-robotic systems. The device consists of a curved, cantilevered steering arm, mounted on an untethered scratch drive actuator. These two components are fabricated monolithically from the same sheet of conductive polysilicon, and receive a common power and control signal through a capacitive coupling with an underlying electrical grid. All locations on the grid receive the same power and control signal, so that the devices can be operated …

How Hard Is It To Cheat In The Gale-Shapley Stable Matching Algorithm, Chien-Chung Huang

Computer Science Technical Reports

We study strategy issues surrounding the stable marriage problem. Under the Gale-Shapley algorithm (with men proposing), a classical theorem says that it is impossible for every liar to get a better partner. We try to challenge this theorem. First, observing a loophole in the statement of the theorem, we devise a coalition strategy in which a non-empty subset of the liars gets a better partner and no man is worse off than before. This strategy is restricted in that not everyone has the incentive to cheat. We attack the classical theorem further by means of randomization. However, this theorem shows …

Obesity, Self-Complexity, And Compartmentalization: On The Implications Of Obesity For Self-Concept Organization, Bruce E. Blaine, C. E. Johnson

Statistics Faculty/Staff Publications

The relationship between obesity and structural aspects of the self-concept was examined in adult women. Participants were 119 adult women [age range: 18-73, M=26.9; body mass index (BMI) range: 16.2-54.7, M=27.3] who completed measures of self-esteem, self-complexity, and the spontaneous self-concept. BMI was associated with less complex and more compartmentalized self-knowledge and more frequent mention of weight-stereotypic traits as self-descriptive. The findings are discussed in the context of research on obesity- related stigma.

Five Years At The Magazine, Frank A. Farris

Mathematics and Computer Science

What do the editors of MAA journals do? What is so different about editing expository mathematics? After my five years as editor of Mathematics Magazine, I have strong opinions about these matters. The goal of most mathematics journals is to print the very latest results from the forefront of research. The goal of Mathematics Magazine is to remind us all why we loved mathematics in the first place, with stimulating articles and notes accessible to advanced undergraduates.

A Digital Pixel Sensor Array With Programmable Dynamic Range, A. Kitchen, A. Bermak, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

This paper presents a digital pixel sensor (DPS) array employing a time domain analogue-to-digital conversion (ADC) technique featuring adaptive dynamic range and programmable pixel response. The digital pixel comprises a photodiode, a voltage comparator, and an 8-bit static memory. The conversion characteristics of the ADC are determined by an array-based digital control circuit, which linearizes the pixel response, and sets the conversion range. The ADC response is adapted to different lighting conditions by setting a single clock frequency. Dynamic range compression was also experimentally demonstrated. This clearly shows the potential of the proposed technique in overcoming the limited dynamic range …

Some New Results Of Regular Hadamard Matrices And Sbibd Ii, Tianbing Xia, M. Xia, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper we prove that there exist 4—{k2; 1/2k(k—1); k(k—2)} SDS, regular Hadamard matrices of order 4k2, and SBIBD(4k2, 2k2 + k, k2 + k) for k = 47, 71, 151, 167, 199, 263, 359, 439, 599, 631, 727, 919, 5q1, 5q2N, 7q3, where ql, q2 and q3 are prime power such that ql ≡ 1(mod 4), q2 ≡ 5(mod 8) and q3 ≡ 3(mod 8), N = 2a3bt2, a, b = 0 or 1, t ≠ 0 is an arbitrary integer. We find new SBIBD(4k2, 2k2 + k, k2 + k) for 43 values of k less than …

Culture As Concept And Influence In Environmental Research And Management, Lesley M. Head, D. Trigger, J. Mulcock

Faculty of Science - Papers (Archive)

Given that human activities have been implicated in the vast majority of contemporary environmental problems, it might be expected that research effort into those activities and the attitudes from which they stem would be both strongly supported by funding agencies, and of central interest to environmental scientists and land managers. In this paper we focus on an undervalued area of environmental humanities research—cultural analysis of the beliefs, practices and often unarticulated assumptions which underlie human–environmental relations. In discussing how cultural processes are central to environmental attitudes and behaviours, and how qualitative research methods can be used to understand them in …

Scaling Byzantine Fault-Tolerant Replication To Wide Area Networks, Yair Amir, Claudiu Danilov, Danny Dolev, Jonathan Kirsch, John Lane, Josh Olsen, David Zage

Department of Computer Science Technical Reports

No abstract provided.

The Sbc-Tree: An Index For Run-Length Compressed Sequences, Mohamed Y. Eltabakh, Wing-Kai Hon, Rahul Shah, Walid G. Aref, Jeffrey S. Vitter

Department of Computer Science Technical Reports

No abstract provided.

Disc Separation Of The Schur Complement Of Diagonally Dominant Matrices And Determinantal Bounds, Jianzhou Liu, Fuzhen Zhang

Mathematics Faculty Articles

We consider the Gersgorin disc separation from the origin for (doubly) diagonally dominant matrices and their Schur complements, showing that the separation of the Schur complement of a (doubly) diagonally dominant matrix is greater than that of the original grand matrix. As application we discuss the localization of eigenvalues and present some upper and lower bounds for the determinant of diagonally dominant matrices.

Physics Department News, December 2005, College Of Arts And Sciences

Physics Newsletter

Contents from Volume 4, Issue 1:

• A Note from the Editor
• From the Chair
• What’s New at the University
• Faculty Highlights
• Staff Highlights
• ICPEAC 2009
• Year of Physics 2005
• PhysTEC
• Alumni News
• Student News
• Annual Student Awards
• Recent Graduates
• Department Roster
• Feedback/Update Reply For

Autism And Parental Marital Satisfaction: The Role Of Adequacy Of Resources, Geneeta Kaliah Chambers

Loma Linda University Electronic Theses, Dissertations & Projects

The goal of the present study was to expand on the existing literature exploring families with children who have developmental disabilities, particularly autism. Previous studies have been constrained by univariate approaches that have failed to adequately capture the nuances of family functioning. Using an ecological/context approach, stemming from an ongoing research program conducted within a university-based treatment center, the present study attempted to improve on the conceptualization of interrelationships among family members and the role that contextual factors play within that dynamic. Specifically, the present study explored the influence of children’s level of autism on parents’ reports of their marital …

Using An Easy-To-Use And Free Tool In Teaching And Researching Networks And Security Issues, Victor A. Clincy

Faculty Articles

ITGuru is a powerful simulation environment developed by OpNET Corporation. ITGuru is unique because of its ability to model the entire networking domain, including its routers, switches, protocols, servers, and the individual applications they support. ITGuru improves network researchers' and instructors' ability to identify and solve problems throughout the network. The OpNET Corporation provides a FREE academic copy of their simulation environment to universities for both teaching and research.

Soft-Gluon Corrections To Hard-Scattering Cross Sections Through Nnnlo, Nikolaos Kidonakis

Faculty Articles

I present a systematic approach to calculating soft-gluon corrections through next-to-next-to-nextto-leading order for arbitrary hard-scattering cross sections. Using a unified approach, master formulas are derived for processes with both simple and complex color flows. Applications and numerical results are given for some processes of interest, including charged Higgs production and top quark production in the Standard Model and beyond.

Architecture And Execution Model For A Survivable Workflow Transaction Infrastructure, Haraldur D. Thorvaldsson, Kenneth J. Goldman

All Computer Science and Engineering Research

We present a novel architecture and execution model for an infrastructure supporting fault-tolerant, long-running distributed applications spanning multiple administrative domains. Components for both transaction processing and persistent state are replicated across multiple servers, en-suring that applications continue to function correctly de-spite arbitrary (Byzantine) failure of a bounded number of servers. We give a formal model of application execution, based on atomic execution steps, linearizability and a sep-aration between data objects and transactions that act on them. The architecture is designed for robust interoperability across domains, in an open and shared Internet computing infrastructure. A notable feature supporting cross-domain applications is …

M4@Si28 (M=Al,Ga) Metal-Encapsulated Tetrahedral Silicon Fullerene, Yi Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

It is known that silicon fullerenes cannot maintain perfect cage structures like carbon fullerenes. Previous density-functional theory calculations have shown that even with encapsulated species, nearly all endohedral silicon fullerenes exhibit highly puckered cage structures in comparison with their carbon counterparts. In this work, we present theoretical evidences that the tetrahedral fullerene cage Si₂₈ can be fully stabilized by encapsulating a tetrahedral metallic cluster (Al₄ or Ga₄). To our knowledge, this is the first predicted endohedral silicon fullerene that can retain perfectly the same cage structure (without puckering) as the carbon fullerene counterpart (T_{d …}

Studying The Performance Of A Firewall In Network Courses, José M. Garrido

Faculty Articles

This paper presents a simple simulation model of a firewall to derive several performance metrics and briefly argues on the importance and value of modeling and simulation in courses that study various aspects of perimeter defense in network security.

The simulation model mentioned previously is part of an effort by faculty of our department to develop a multi-disciplinary repository of computational models that includes object-oriented discrete-event simulation models. One of the goals of this repository is to build resources that help educate students of computer science, software engineering, and information technology, in modeling and information security.

This and other network …