Anchor Nodes Placement for Effective Passive Localization

Anchor Nodes Placement for Effective Passive Localization

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Date: August 2010
Creator: Pasupathy, Karthikeyan
Description: Wireless sensor networks are composed of sensor nodes, which can monitor an environment and observe events of interest. These networks are applied in various fields including but not limited to environmental, industrial and habitat monitoring. In many applications, the exact location of the sensor nodes is unknown after deployment. Localization is a process used to find sensor node's positional coordinates, which is vital information. The localization is generally assisted by anchor nodes that are also sensor nodes but with known locations. Anchor nodes generally are expensive and need to be optimally placed for effective localization. Passive localization is one of the localization techniques where the sensor nodes silently listen to the global events like thunder sounds, seismic waves, lighting, etc. According to previous studies, the ideal location to place anchor nodes was on the perimeter of the sensor network. This may not be the case in passive localization, since the function of anchor nodes here is different than the anchor nodes used in other localization systems. I do extensive studies on positioning anchor nodes for effective localization. Several simulations are run in dense and sparse networks for proper positioning of anchor nodes. I show that, for effective passive localization, the ...
Contributing Partner: UNT Libraries
Dynamic intimate contact social networks and epidemic interventions

Dynamic intimate contact social networks and epidemic interventions

Date: 2008
Creator: Corley, Courtney; Mikler, Armin R.; Cook, Diane J., 1963- & Singh, Karan P.
Description: This article discusses dynamic intimate contact social networks and epidemic interventions.
Contributing Partner: UNT College of Engineering
Simulation of local watershed nutrient and sediment delivery to Lake Texoma.

Simulation of local watershed nutrient and sediment delivery to Lake Texoma.

Date: May 2004
Creator: Upton, Alexandra C.
Description: A hydrologic model and watershed export model was used to estimate the loading of nutrients and total suspended solids from un-gaged local watersheds associated with Lake Texoma. Discharge to the reservoir from local watersheds was predicted using a modification of the curve number method in HEC Hydrologic Modeling System (HEC-HMS). Event mean concentrations were applied to land use to estimate loadings of nutrients and TSS. Total discharge from the local watersheds was estimated to be 3.02 x 107 cubic meters for a study window of March 1 to May 31, 1997, less than 10 percent of the input to the lake from the Red River and Washita River systems. Loadings were estimated to be 33,553 kg nitrogen, 4,401 kg phosphorus, and 3,423,140 kg TSS. The models and results obtained from their application appear to have potential utility for use in a water quality management decision support system for the reservoir.
Contributing Partner: UNT Libraries
Bias and Precision of the Squared Canonical Correlation Coefficient under Nonnormal Data Conditions

Bias and Precision of the Squared Canonical Correlation Coefficient under Nonnormal Data Conditions

Date: August 2006
Creator: Leach, Lesley Ann Freeny
Description: This dissertation: (a) investigated the degree to which the squared canonical correlation coefficient is biased in multivariate nonnormal distributions and (b) identified formulae that adjust the squared canonical correlation coefficient (Rc2) such that it most closely approximates the true population effect under normal and nonnormal data conditions. Five conditions were manipulated in a fully-crossed design to determine the degree of bias associated with Rc2: distribution shape, variable sets, sample size to variable ratios, and within- and between-set correlations. Very few of the condition combinations produced acceptable amounts of bias in Rc2, but those that did were all found with first function results. The sample size to variable ratio (n:v)was determined to have the greatest impact on the bias associated with the Rc2 for the first, second, and third functions. The variable set condition also affected the accuracy of Rc2, but for the second and third functions only. The kurtosis levels of the marginal distributions (b2), and the between- and within-set correlations demonstrated little or no impact on the bias associated with Rc2. Therefore, it is recommended that researchers use n:v ratios of at least 10:1 in canonical analyses, although greater n:v ratios have the potential to produce even less bias. ...
Contributing Partner: UNT Libraries
Modeling Infectious Disease Spread Using Global Stochastic Field Simulation

Modeling Infectious Disease Spread Using Global Stochastic Field Simulation

Date: August 2006
Creator: Venkatachalam, Sangeeta
Description: Susceptibles-infectives-removals (SIR) and its derivatives are the classic mathematical models for the study of infectious diseases in epidemiology. In order to model and simulate epidemics of an infectious disease, a global stochastic field simulation paradigm (GSFS) is proposed, which incorporates geographic and demographic based interactions. The interaction measure between regions is a function of population density and geographical distance, and has been extended to include demographic and migratory constraints. The progression of diseases using GSFS is analyzed, and similar behavior to the SIR model is exhibited by GSFS, using the geographic information systems (GIS) gravity model for interactions. The limitations of the SIR and similar models of homogeneous population with uniform mixing are addressed by the GSFS model. The GSFS model is oriented to heterogeneous population, and can incorporate interactions based on geography, demography, environment and migration patterns. The progression of diseases can be modeled at higher levels of fidelity using the GSFS model, and facilitates optimal deployment of public health resources for prevention, control and surveillance of infectious diseases.
Contributing Partner: UNT Libraries
Simulation Study of Hybrid Ground Source Heat Pump System in the Hot-Humid Climate

Simulation Study of Hybrid Ground Source Heat Pump System in the Hot-Humid Climate

Date: August 2011
Creator: Zhu, Jiang
Description: The beachfront hotel with hybrid geothermal heat pump system (HyGSHP), located in the hot-humid climate, is simulated by TRNSYS in the thesis, and the simulation results are validated by the measured data. The simulation of alternative HVAC systems, complete ground source heat pump and conventional air source heat pump, are included to conduct the comparative study with HyGSHP based on the energy consumption and life cycle analysis. The advantages and disadvantages of HyGSHP are discussed in the thesis. Two ground source heat exchanger parameters, U-tube size and grout materials, are investigated in order to study the effects on the ground heat exchanger thermal performance. The preliminary work and results are shown in the thesis.
Contributing Partner: UNT Libraries
An Empirical Evaluation of Communication and Coordination Effectiveness in Autonomous Reactive Multiagent Systems

An Empirical Evaluation of Communication and Coordination Effectiveness in Autonomous Reactive Multiagent Systems

Date: May 2005
Creator: Hurt, David
Description: This thesis describes experiments designed to measure the effect of collaborative communication on task performance of a multiagent system. A discrete event simulation was developed to model a multi-agent system completing a task to find and collect food resources, with the ability to substitute various communication and coordination methods. Experiments were conducted to find the effects of the various communication methods on completion of the task to find and harvest the food resources. Results show that communication decreases the time required to complete the task. However, all communication methods do not fare equally well. In particular, results indicate that the communication model of the bee is a particularly effective method of agent communication and collaboration. Furthermore, results indicate that direct communication with additional information content provides better completion results. Cost-benefit models show some conflicting information, indicating that the increased performance may not offset the additional cost of achieving that performance.
Contributing Partner: UNT Libraries
Adaptación de un modelo de claros para el estudio de la dinámica de un bosque estacional en los llanos occidentales de Venezuela

Adaptación de un modelo de claros para el estudio de la dinámica de un bosque estacional en los llanos occidentales de Venezuela

Date: 2010
Creator: Angulo, Hirma Ramírez; Acevedo, Miguel F.; Ataroff, Michele & Lezama, Armando Torres
Description: Article discussing the adaptation of a gap model to the study of the dynamics of a seasonal forest in the western plains of Venezuela.
Contributing Partner: UNT College of Engineering
Ability of Offenders with Psychopathic Traits to Simulate Cognitive and Affective Empathy

Ability of Offenders with Psychopathic Traits to Simulate Cognitive and Affective Empathy

Date: August 2013
Creator: Robinson, Emily V.
Description: The accurate assessment of psychopathy constitutes a critical component of forensic assessments addressing offender populations. Among the core characteristics of psychopathy, the interpersonal component of deception and empathic deficits are prominently observed in offenders with psychopathic traits. Given the negative consequences of being classified as a psychopath, offenders may be likely to minimize their psychopathic traits. In particular, no research has investigated whether offenders with psychopathic traits are able to simulate empathy in an effort to mask their cognitive or affective empathy deficits (e.g., lack of remorse about offenses). The present study aims to contribute to the literature with regard to the simulation of empathy. Using a mixed between- and within-subjects design, 81 male detainees were placed into (a) a low psychopathy group, (b) a moderate psychopathy group, or (c) a high psychopathy group based on the Psychopathy Checklist – Revised. For the within-subjects component, all offenders answered empathy questionnaires under genuine and simulation conditions. Results indicate the sample possessed cognitive empathy, but did not display affective empathy under genuine instructions. Under simulation instructions, participants significantly increased their scores on several empathy measures. The implications of simulated empathy and comparisons between groups regarding simulation abilities are discussed.
Contributing Partner: UNT Libraries
First Principle Calculations of the Structure and Electronic Properties of Pentacene Based Organic and ZnO Based Inorganic Semiconducting Materials

First Principle Calculations of the Structure and Electronic Properties of Pentacene Based Organic and ZnO Based Inorganic Semiconducting Materials

Date: May 2012
Creator: Li, Yun
Description: In this thesis, I utilize first principles density functional theory (DFT) based calculations to investigate the structure and electronic properties including charge transfer behaviors and work function of two types of materials: pentacene based organic semiconductors and ZnO transparent conducting oxides, with an aim to search for high mobility n-type organic semiconductors and fine tuning work functions of ZnO through surface modifications. Based on DFT calculations of numerous structure combinations, I proposed a pentacene and perfluoro-pentacene alternating hybrid structures as a new type of n-type semiconductor. Based on the DFT calculations and Marcus charge transfer theory analysis, the new structure has high charge mobility and can be a promising new n-type organic semiconductor material. DFT calculations have been used to systematically investigate the effect of surface organic absorbate and surface defects on the work function of ZnO. It was found that increasing surface coverage of organic groups and decreasing surface defects lead to decrease of work functions, in excellent agreement with experimental results. First principles based calculations thus can greatly contribute to the investigating and designing of new electronic materials.
Contributing Partner: UNT Libraries
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