Digital Commons Network^™

Reactivity Of Acyclic (Pentadienyl)Iron(1+) Cations: Synthetic Studies Directed Toward The Frondosins, Do W. Lee, Rajesh K. Pandey, Sergey V. Lindeman, William A. Donaldson

Chemistry Faculty Research and Publications

A short, 4-step route to the scaffold of frondosin A and B is reported. The [1-methoxycarbonyl-5-(2′,5′-dimethoxyphenyl)pentadienyl]Fe(CO)₃⁺ cation was prepared in two steps from (methyl 6-oxo-2,4-hexadienoate)Fe(CO)₃. Reaction of this cation with isopropenyl Grignard or cyclohexenyllithium reagents affords (2-alkenyl-5-aryl-1-methoxycarbonyl-3-pentene-1,5-diyl)Fe(CO)₃ along with other addition products. Oxidative decomplexation of these (pentenediyl)iron complexes, utilizing CuCl₂, affords 6-aryl-3-methoxycarbonyl-1,4-cycloheptadienes via the presumed intermediacy of a cis-divinylcyclopropane.

Removal Of 2,4-Dichlorophenoxyacetic Acid By Calcined Zn–Al–Zr Layered Double Hydroxide, Allen Chaparadza, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

The adsorption equilibrium, kinetics, and thermodynamics of removal of 2,4-dichlorophenoxy-acetic acid (2,4-D) from aqueous solutions by a calcined Zn–Al layered double hydroxide incorporated with Zr⁴⁺ were studied with respect to time, temperature, pH, and initial 2,4-D concentration. Zr⁴⁺ incorporation into the LDH was used to enhance 2,4-D uptake by creating higher positive charges and surface/layer modification of the adsorbent. The LDH was capable of removing up to 98% of 2,4-D from 5 to 400 ppm aqueous at adsorbent dosages of 500 and 5000 mg L⁻¹. The adsorption was described by a Langmuir-type isotherm. The percentage 2,4-D …

Does Recreational Reading In Native Language Influence Foreign Language Learning Process?, Selami Aydin

The Qualitative Report

Limited studies have been conducted on the effects on recreational reading in native language on foreign language learning, whereas no findings exist on the effects of recreational reading in Turkish as a native language (L1) on English as a foreign language (EFL) learning. Thus, this study aims to investigate the effects of recreational reading in L1 on the process of learning EFL. The sample group consists of 70 learners and a background questionnaire, interviews, oral presentations, classroom discussions, essay papers, and responses to examination questions were used for data collection. The results indicated that recreational reading in L1 has some …

Compositions, Partitions, And Fibonacci Numbers, Andrew Sills

Mathematical Sciences: Faculty Publications

A bijective proof is given for the following theorem: the number of compositions of n into odd parts equals the number of compositions of n+ 1 into parts greater than one. Some commentary about the history of partitions and compositions is provided.

In Search Of A Different Accounting Graduate: Entry-Point Determinants Of Students’ Performance In An Undergraduate Accountancy Degree Programme In Singapore, Poh Sun Seow, Pan, Gary, Siok Wan Joanne Tay

Research Collection School Of Accountancy

This study investigates the association of prior academic achievement, admission interview, critical thinking, mathematical aptitude, gender and age with successful academic performance in an undergraduate accountancy degree programme at a Singapore university. The purpose of revisiting the determinants of academic performance is twofold: firstly, university accounting education in Singapore has changed greatly since Koh and Koh’s earlier study (1999), so this study examines if determinants previously identified as significant continue to be so in the new setting; secondly, the study tests the usefulness of admission interview in identifying applicants who achieve subsequent academic success. All the data on students’ performance …

An Engineered Approach To Stem Cell Culture: Automating The Decision Process For Real-Time Adaptive Subculture Of Stem Cells, Dai Fei Elmer Ker, Lee E. Weiss, Silvina N. Junkers, Mei Chen, Zhaozheng Yin, Mike F. Sandbothe, Seungil Huh, Sungeun Eom, Ryoma Bise, Elvira Osuna-Highley, Takeo Kanade, Phil Gordon Campbell

Computer Science Faculty Research & Creative Works

Current cell culture practices are dependent upon human operators and remain laborious and highly subjective, resulting in large variations and inconsistent outcomes, especially when using visual assessments of cell confluency to determine the appropriate time to subculture cells. Although efforts to automate cell culture with robotic systems are underway, the majority of such systems still require human intervention to determine when to subculture. Thus, it is necessary to accurately and objectively determine the appropriate time for cell passaging. Optimal stem cell culturing that maintains cell pluripotency while maximizing cell yields will be especially important for efficient, cost-effective stem cell-based therapies. …

Gorenstein Injective Modules, Emily Mclean

College of Graduate Studies: Theses & Dissertations

One of the open problems in Gorenstein homological algebra is: when is the class of Gorenstein injective modules closed under arbitrary direct sums? Our main result gives a sufficient condition for this to happen. We prove that when the ring R is noetherian and such that every R-module has finite Gorenstein injective dimension, every direct sum of Gorenstein injective modules is still Gorenstein injective.

Decentralized Optimal Control Of A Class Of Interconnected Nonlinear Discrete-Time Systems By Using Online Hamilton-Jacobi-Bellman Formulation, Shahab Mehraeen, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the direct neural dynamic programming technique is utilized to solve the Hamilton-Jacobi-Bellman equation forward-in-time for the decentralized near optimal regulation of a class of nonlinear interconnected discrete-time systems with unknown internal subsystem and interconnection dynamics, while the input gain matrix is considered known. Even though the unknown interconnection terms are considered weak and functions of the entire state vector, the decentralized control is attempted under the assumption that only the local state vector is measurable. the decentralized nearly optimal controller design for each subsystem consists of two neural networks (NNs), an action NN that is aimed to …

A Dynamic Programming Approach: Improving The Performance Of Wireless Networks, Sandeep Kolli, Maciej Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Traditional wireless networks focus on transparent data transmission where the data are processed at either the source or destination nodes. in contrast, the proposed approach aims at distributing data processing among the nodes in the network thus providing a higher processing capability than a single device. Moreover, energy consumption is balanced in the proposed scheme since the energy intensive processing will be distributed among the nodes. the performance of a wireless network is dependent on a number of factors including the available energy, energy efficiency, data processing delay, transmission delay, routing decisions, security architecture etc. Typical existing distributed processing schemes …

A Bayesian Model For Gene Family Evolution, Liang Liu, Lili Yu, Venugopal Kalavacharla, Zhanji Liu

Biostatistics: Faculty Publications

Background

A birth and death process is frequently used for modeling the size of a gene family that may vary along the branches of a phylogenetic tree. Under the birth and death model, maximum likelihood methods have been developed to estimate the birth and death rate and the sizes of ancient gene families (numbers of gene copies at the internodes of the phylogenetic tree). This paper aims to provide a Bayesian approach for estimating parameters in the birth and death model.

Results

We develop a Bayesian approach for estimating the birth and death rate and other parameters in the birth …

A Pomdp Model For Guiding Taxi Cruising In A Congested Urban City, Lucas Agussurja, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider a partially observable Markov decision process (POMDP) model for improving a taxi agent cruising decision in a congested urban city. Using real-world data provided by a large taxi company in Singapore as a guide, we derive the state transition function of the POMDP. Specifically, we model the cruising behavior of the drivers as continuous-time Markov chains. We then apply dynamic programming algorithm for finding the optimal policy of the driver agent. Using a simulation, we show that this policy is significantly better than a greedy policy in congested road network.

A Brain-Inspired Model Of Hierarchical Planner, Budhitama Subagdja, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Hierarchical planning is an approach of planning by composing and executing hierarchically arranged plans to solve some problems. Most symbolic-based hierarchical planners have been devised to allow the knowledge to be described expressively. However, a great challenge is to automatically seek and acquire new plans on the fly. This paper presents a novel neural-based model of hierarchical planning that can seek and acquired new plans on-line if the necessary knowledge are lacking. Inspired by findings in neuropsychology, plans can be inherently learnt, retrieved, and manipulated simultaneously rather than discretely processed like in most symbolic approaches. Using a multi-channel adaptive resonance …

Investigating Combinatorial Approaches In Virtual Screening On Human Inducible 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase (Pfkfb3): A Case Study For Small Molecule Kinases, Robert B. Crochet, Michael C. Cavalier, Minsuh Seo, Jeong Do Kim, Young Sun Yim, Seung Jong Park, Yong Hwan Lee

Computer Science Faculty Research & Creative Works

Efforts toward improving the predictiveness in tier-based approaches to virtual screening (VS) have mainly focused on protein kinases. Despite their significance as drug targets, small molecule kinases have been rarely tested with these approaches. In this paper, we investigate the efficacy of a pharmacophore screening-combined structure-based docking approach on the human inducible 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, an emerging target for cancer chemotherapy. Six out of a total 1364 compounds from NCI's Diversity Set II were selected as true actives via throughput screening. Using a database constructed from these compounds, five programs were tested for structure-based docking (SBD) performance, the MOE of which showed …

Profit-Maximizing Firm Investments In Customer Information Security, Yong Yick Lee, Robert J. Kauffman, Ryan Sougstad

Research Collection School Of Computing and Information Systems

When a customer interacts with a firm, extensive personal information often is gathered without the individual's knowledge. Significant risks are associated with handling this kind of information. Providing protection may reduce the risk of the loss and misuse of private information, but it imposes some costs on both the firm and its customers. Nevertheless, customer information security breaches still may occur. They have several distinguishing characteristics: (1) typically it is hard to quantify monetary damages related to them; (2) customer information security breaches may be caused by intentional attacks, as well as through unintentional organizational and customer behaviors; and (3) …

Software Process Evaluation: A Machine Learning Approach, Ning Chen, Steven C. H. Hoi, Xiaokui Xiao

Research Collection School Of Computing and Information Systems

Software process evaluation is essential to improve software development and the quality of software products in an organization. Conventional approaches based on manual qualitative evaluations (e.g., artifacts inspection) are deficient in the sense that (i) they are time-consuming, (ii) they suffer from the authority constraints, and (iii) they are often subjective. To overcome these limitations, this paper presents a novel semi-automated approach to software process evaluation using machine learning techniques. In particular, we formulate the problem as a sequence classification task, which is solved by applying machine learning algorithms. Based on the framework, we define a new quantitative indicator to …

Are There Contagion Effects In Information Technology And Business Process Outsourcing?, Arti Mann, Robert J. Kauffman, Kunsoo Han, Barrie R. Nault

Research Collection School Of Computing and Information Systems

We model the diffusion of IT outsourcing using announcements about IT outsourcing deals. We estimate a lognormal diffusion curve to test whether IT outsourcing follows a pure diffusion process or there are contagion effects involved. The methodology permits us to study the consequences of outsourcing events, especially mega-deals with IT contract amounts that exceed US$1 billion. Mega-deals act, we theorize, as precipitating events that create a strong basis for contagion effects and are likely to affect decision-making by other firms in an industry. Then, we evaluate the role of different communication channels in the diffusion process of IT outsourcing by …

Magnetic Susceptibility As A Proxy For Investigating Microbially Mediated Iron Reduction, Farag M. Mewafy, Estella A. Atekwana, D. Dale Werkema, Lee D. Slater, Dimitrios Ntarlagiannis, Andre Revil, Magnus E. Skold, Geoffrey N. Delin

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We investigated magnetic susceptibility (MS) variations in hydrocarbon contaminated sediments. Our objective was to determine if MS can be used as an intrinsic bioremediation indicator due to the activity of iron-reducing bacteria. A contaminated and an uncontaminated core were retrieved from a site contaminated with crude oil near Bemidji, Minnesota and subsampled for MS measurements. The contaminated core revealed enriched MS zones within the hydrocarbon smear zone, which is related to iron-reduction coupled to oxidation of hydrocarbon compounds and the vadose zone, which is coincident with a zone of methane depletion suggesting aerobic or anaerobic oxidation of methane is coupled …

Paim: Peer-Based Automobile Identity Management In Vehicular Ad-Hoc Network, Anna Squicciarini, Dan Lin, Alessandro Mancarella

Computer Science Faculty Research & Creative Works

The emerging Vehicular Ad-hoc Network (VANET) technology will enable many exciting applications such as vehicular safety assistance and mobile entertainment. One of the key challenges toward successful roll-out of VANET applications is to provide security and privacy preserving mechanisms for users. Existing efforts on this topic rely heavily on infrastructure like road-side units which however are not available everywhere. to minimize the dependence on infrastructure, we propose a novel Peer-Based Automobile Identity Management (PAIM) Framework which is mainly based on vehicle-to-vehicle communication. PAIM supports dynamic event-Based moving zones formed by vehicles sharing common interest. PAIM achieves the level of privacy …

C(Naphthyl)-H Bond Activation By Rhodium: Isolation, Characterization And Td-Dft Study Of The Cyclometallates, Achintesh Narayan Biswas, Purak K. Das, Sandip K. Sengupta, Amitava Choudhury, Pinaki K. Bandyopadhyay

Chemistry Faculty Research & Creative Works

The C1(naphthyl)-H, C2(naphthyl)-H, C3(naphthyl)-H and C8(naphthyl)-H bonds of the naphthyl group present in a group of naphthylazo-2'-hydroxyarenes (H ₂L) have been activated by [Rh(PPh ₃) ₃Cl] in a toluene medium. Here the cyclometallation is accompanied by metal centered oxidation [Rh(i)?Rh(iii)]. All the resulting cyclometallates [Rh(PPh ₃) ₂(L)Cl] (2-5) have been isolated in a pure form. The characterization of the cyclometallates [Rh(PPh ₃) ₂(L)Cl] have been done on the basis of spectral (IR, UV-vis, and FAB mass) data. The structures of the representative cyclometallates 2a, 3a, 4a, 4b and 5b have been determined by …

Reflection And Transmission Of Line-Source Excited Pulsed Em Fields At A Thin, High-Contrast Layer With Dielectric And Conductive Properties, Adrianus T. De Hoop, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A methodology is presented for analytically modeling the reflection and transmission of line-source excited pulsed electromagnetic fields fields at a thin, planar, high-contrast layer with dielectric and conductive properties. Closed-form time-domain expressions are derived for the field components in a two-dimensional setting via an extension of the Cagniard-DeHoop method. © 2011 IEEE.

A New Closed-Form Evaluation Of Layered Medium Green's Function, Yongpin P. Chen, Weng Cho Chew, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A new closed-form evaluation of layered medium Green's function is proposed in this paper. The discrete complex image method (DCIM) is extended to sampling along the Sommerfeld branch cut, to capture the far field interaction. Contour deformation technique is applied to decompose the Green's function into radiation modes (branch cut integration) and guided modes (surface-wave poles). The matrix pencil method is implemented to get a closed-form solution, with the help of an alternative Sommerfeld identity. Numerical results are presented to demonstrate the accuracy of this method. © 2011 IEEE.

Florida Charter Schools: The Effects Of Types And Socioeconomic Status On Academic Achievement, Reginald Thompson

Doctoral Dissertations and Projects

No Child Left Behind (NCLB) was established in 2002 with the primary goal of closing the achievement gap between low socioeconomic students and their more advantaged peers. Charter schools are a part of NCLB's school choice policy and are intended to be a form of intervention to close the achievement gap. Much research has been conducted to measure charter school student achievement compared to regular public schools. But little has been done in distinguishing the differences between charter schools and their impact on student achievement. This quantitative study identifies the different types of public charter schools in Florida using Carpenter's …

Linear Programming-Based Estimators In Simple Linear Regression, Daniel P. A. Preve, Marcelo C. Medeiros

Research Collection School Of Economics

In this paper we introduce a linear programming estimator (LPE) for the slope parameter in a constrained linear regression model with a single regressor. The LPE is interesting because it can be superconsistent in the presence of an endogenous regressor and, hence, preferable to the ordinary least squares estimator (LSE). Two different cases are considered as we investigate the statistical properties of the LPE. In the first case, the regressor is assumed to be fixed in repeated samples. In the second, the regressor is stochastic and potentially endogenous. For both cases the strong consistency and exact finite-sample distribution of the …

Intertemporal Substitution In The Time Allocation Of Married Women, Ken Yamada

Research Collection School Of Economics

This paper studies a life-cycle model of home production to examine how married women change their allocation of time in response to evolutionary movements along the life-cycle wage profile in Japan. After accounting for the potential bias due to heterogeneity, measurement error, weak instruments, and missing data, the estimates of intertemporal substitution elasticity obtained from the home production model are moderate and similar to those obtained from the standard labor supply model.

Learning Human Emotion Patterns For Modeling Virtual Humans, Shu Feng, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Emotion modeling is a crucial part in modeling virtual humans. Although various emotion models have been proposed, most of them focus on designing specific appraisal rules. As there is no unified framework for emotional appraisal, the appraisal variables have to be defined beforehand and evaluated in a subjective way. In this paper, we propose an emotion model based on machine learning methods by taking the following position: an emotion model should mirror actual human emotion in the real world and connect tightly with human inner states, such as drives, motivations and personalities. Specifically, a self-organizing neural model called Emotional Appraisal …

Finding Relevant Answers In Software Forums, Swapna Gottopati, David Lo, Jing Jiang

Research Collection School Of Computing and Information Systems

Online software forums provide a huge amount of valuable content. Developers and users often ask questions and receive answers from such forums. The availability of a vast amount of thread discussions in forums provides ample opportunities for knowledge acquisition and summarization. For a given search query, current search engines use traditional information retrieval approach to extract webpages containing relevant keywords. However, in software forums, often there are many threads containing similar keywords where each thread could contain a lot of posts as many as 1,000 or more. Manually finding relevant answers from these long threads is a painstaking task to …

Exploring Tweets Normalization And Query Time Sensitivity For Twitter Search, Zhongyu Wei, Wei Gao, Lanjun Zhou, Binyang Li, Kam-Fai Wong

Research Collection School Of Computing and Information Systems

This paper presents our work for the Realtime Adhoc Task of TREC 2011 Microblog Track. Microblog texts like tweets are generally characterized by the inclusion of a large proportion of irregular expressions, such as ill-formed words, which can lead to significant mismatch between query terms and tweets. In addition, Twitter queries are distinguished from Web queries with many unique characteristics, one of which reflects the clearly distinct temporal aspects of Twitter search behavior. In this study, we deal with the first problem by normalizing tweet texts and the second by capturing the temporal characteristics of topic. We divided topics into …

Specification Sensitivity In Right-Tailed Unit Root Testing For Explosive Behavior, Peter C. B. Phillips, Shu-Ping Shi, Jun Yu

Research Collection School Of Economics

Right-tailed unit root tests have proved promising for detecting exuberance in economic and financial activities. Like left-tailed tests, the limit theory and test performance are sensitive to the null hypothesis and the model specification used in parameter estimation. This paper aims to provide some empirical guidelines for the practical implementation of right-tailed unit root tests, focusing on the sup ADF test of Phillips, Wu and Yu (2011), which implements a right-tailed ADF test repeatedly on a sequence of forward sample recursions. We analyze and compare the limit theory of the sup ADF test under deferent hypotheses and model specifications. The …

Specification Testing For Nonparametric Structural Models With Monotonicity In Unobservables, Stefan Hoderlein, Liangjun Su, Halbert White

Research Collection School Of Economics

Monotonicity in a scalar unobservable is a now common assumption in economic theory and applications. Among other things, it allows one to recover the underlying structural function from certain conditional quantiles of observables. Nevertheless, monotonicity is a strong assumption, and its failure can have substantive adverse consequences for structural inference. So far, there are no generally applicable nonparametric specification tests designed to detect monotonicity failure. This paper provides such a test for cross-section data. We show how to exploit an exclusion restriction together with a conditional independence assumption, plausible in a variety of applications, to construct a test. Our statistic …

Support Varieties And Representation Type Of Self-Injective Algebras, Jorg Feldvoss, Sarah Witherspoon

University Faculty and Staff Publications

We use the theory of varieties for modules arising from Hochschild cohomology to give an alternative version of the wildness criterion of Bergh and Solberg [7]: If a finite dimensional self-injective algebra has a module of complexity at least 3 and satisfies some finiteness assumptions on Hochschild cohomology, then the algebra is wild. We show directly how this is related to the analogous theory for Hopf algebras that we developed in [23]. We give applications to many different types of algebras: Hecke algebras, reduced universal enveloping algebras, small half- quantum groups, and Nichols (quantum symmetric) algebras.