1,504 research outputs found

    Using Optimization and Simulation Techniques to Estimate Initial Weevil Populations

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    In this paper, a mathematical programming and simulation method is used to estimate the number of weevils (Neochetina bruchi Hustache, and N. eichhorniae Warner) necessary to initialize the INSECT model which simulates the biological control of waterhyacinth by the weevils. The objective is to estimate the initial input values for the adult population so that the sum of the absolute differences between the observed and the simulated numbers of weevils is minimized. In general, the simulated values using the initial values obtained from the mathematical programming problem were within the 95% confidence intervals of the actual field observations. Also, in many cases, the simulation results indicated trends similar to those indicated by the field data in both timing and the numbers of weevils

    COTGAME: Cotton Insect Pest Management Simulation Game

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    An interactive version of the Cotton and Insect Management (CIM) model was developed to aid individuals in improving their insect pest management decision making skills. This version, COTGAME, allowed the user to encounter situations and make decisions during the simulated cotton crop growing season. The intermediate results of these decisions were immediately delivered in the form of a report on the current status of the crop and insect populations. Based on the information presented in this status report, the user would make additional management decisions and take tactical actions. Once the harvest date had been reached, the economics of the simulated production season was presented to allow the user to evaluate the decisions. The use of COTGAME has been a way to apply the technology in a detailed crop growth model to improving insect pest management skills

    A Computer Simulation Model of Waterhyacinth and Weevil Interactions

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    A personal computer simulation model termed INSECT has been developed to evaluate biological control of waterhyacinth (Eichhornia crassipes (Mart.) Solms.) by two species of weevil (Neochetina eichhorniae Warner, and N. bruchi Hustache). The model results were compared with the data from three different locations. For each data set, the simulated plant biomass, adult and larva populations were plotted aqainst the 95% confidence intervals of the actual field observations. In many cases, the simulation results were within the 95% confidence intervals, and especially during the growing season, they indicated trends similar to those seen in the field data. However, there were discrepancies in both the magnitude and the trend for early and the late periods of the year. These initial results suggest that development of a model to simulate the impact of a biocontrol agent on waterhyacinth populations is a feasible approach to better understand the interactions within this control system

    Freely Long-Thinking Transformer (FraiLT)

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    Freely Long-Thinking Transformer (FraiLT) is an improved transformer model designed to enhance processing capabilities without scaling up size. It utilizes a recursive approach, iterating over a subset of layers multiple times, and introduces iteration encodings to maintain awareness across these cycles. Iteration encoding allows FraiLT to achieve the interpretive depth of larger models in a compact form. When evaluated on a synthetic story dataset, FraiLT outperformed larger models, showcasing its ability to deliver high-quality performance while reducing memory demands. This model represents a step forward towards more efficient and accessible language models

    Synthesis, characterization, and applications of novel pseudostationary phases in micellar capillary electrophoresis for separation of chiral and archiral compounds h[electronic resource]

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    The research presented in this dissertation involves the synthesis, characterization, and the use of novel surfactants, including both micelles and vesicles, as pseudostationary phases in micellar capillary electrophoresis (MCE) for the separation of achiral and chiral compounds. Separation of environmental pollutants such as 2 to 6-ring polycyclic aromatic hydrocarbons (PAHs) was achieved using poly(sodium undecylenic sulfate). A baseline separation of all 16 PAHs was possible for the first time in MCE by a single-surfactant system. In addition, a surfactant with a phosphated head group, i.e., di(2-ethylhexyl)phosphate (DEHP), was also introduced as a novel pseudostationary phase for separation of 21 weakly and strongly hydrophobic neutral compounds. Acetonitrile at a concentration of 30% (v/v) in combination with 100 mM DEHP gave optimum separation for a mixture of 21 benzene derivatives and PAHs in under 16 minutes. An application of cyclodextrin modified MCE was used for separation of twelve mono-methylbenz[a]anthracene positional isomers using a combination of poly-SUS and b-CD, g-CD or b-CD derivatives. Tartaric acid based vesicular surfactants were synthesized and utilized as novel pseudostationary phases in MCE. Linear solvation energy relationship model was applied to understand the fundamental nature of the solute-surfactant interactions and to investigate the effect of the type and the composition of pseudostationary phases on the retention mechanism and selectivity in MCE. The solute size has the largest influence on the solute retention in MCE. The hydrogen bond accepting ability of the solute is the second most important factor on retention and is the largest contributor towards the selectivity differences between pseudostationary phases used. Another study conducted was the synthesis of sodium N-undecanoyl L-leucinate and co-polymerization of SUL with SUS to make a variety of co-polymerized molecular micelles having both chiral (leucinate) and achiral (sulfate) head groups. These surfactants were applied as novel pseudostationary phases in MCE for separation of chiral and achiral compounds. Aggregation numbers and partial specific volumes of these surfactant systems were determined using fluorescence spectroscopy and densitometry, respectively. Thermodynamic parameters such as enthalpy, entropy, and Gibbs free energy changes upon transfer of analyte(s) from aqueous phase to the pseudostationary phase were also determined

    TRANSLATION-FAVORABLE FLAT SURFACES IN 3-SPACES

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    In the paper, we obtain the complete classification of Translation-Factorable (TF-) surfaces with vanishing Gaussian curvature in Euclidean and Minkowski 3-space

    Evaluation Of The Endocrine Disrupting Potential Of Chemicals Used In Crumb Rubber: A Multi-Factorial Approach

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    Crumb rubber, an infill substance made from repurposed tires, has been examined for its carcinogenic potential but no studies have looked at its endocrine disrupting potential to date. After prioritizing 306 chemical components of crumb rubber using computational models, four endocrine disrupting chemicals (EDCs) thought to possess estrogenic activity were chosen for further in vitro testing. In addition to these chemicals, a crumb rubber concentrated media (CRCM) was created for mixture analysis. Gene expression assays for estrogenic activity were conducted on Ishikawa, HepG2 and MCF-7 immortalized cell lines exposed to 4-tert-octylphenol, dibenz(a,h)anthracene, fluoranthene, chrysene and CRCM. Based on the findings of this study, crumb rubber is a potential mediating factor in harmful reproductive outcomes. Further discussion is needed to juxtapose these biological models with exposure assessment

    Constraint-driven RF test stimulus generation and built-in test

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    With the explosive growth in wireless applications, the last decade witnessed an ever-increasing test challenge for radio frequency (RF) circuits. While the design community has pushed the envelope far into the future, by expanding CMOS process to be used with high-frequency wireless devices, test methodology has not advanced at the same pace. Consequently, testing such devices has become a major bottleneck in high-volume production, further driven by the growing need for tighter quality control. RF devices undergo testing during the prototype phase and during high-volume manufacturing (HVM). The benchtop test equipment used throughout prototyping is very precise yet specialized for a subset of functionalities. HVM calls for a different kind of test paradigm that emphasizes throughput and sufficiency, during which the projected performance parameters are measured one by one for each device by automated test equipment (ATE) and compared against defined limits called specifications. The set of tests required for each product differs greatly in terms of the equipment required and the time taken to test individual devices. Together with signal integrity, precision, and repeatability concerns, the initial cost of RF ATE is prohibitively high. As more functionality and protocols are integrated into a single RF device, the required number of specifications to be tested also increases, adding to the overall cost of testing, both in terms of the initial and recurring operating costs. In addition to the cost problem, RF testing proposes another challenge when these components are integrated into package-level system solutions. In systems-on-packages (SOP), the test problems resulting from signal integrity, input/output bandwidth (IO), and limited controllability and observability have initiated a paradigm shift in high-speed analog testing, favoring alternative approaches such as built-in tests (BIT) where the test functionality is brought into the package. This scheme can make use of a low-cost external tester connected through a low-bandwidth link in order to perform demanding response evaluations, as well as make use of the analog-to-digital converters and the digital signal processors available in the package to facilitate testing. Although research on analog built-in test has demonstrated hardware solutions for single specifications, the paradigm shift calls for a rather general approach in which a single methodology can be applied across different devices, and multiple specifications can be verified through a single test hardware unit, minimizing the area overhead. Specification-based alternate test methodology provides a suitable and flexible platform for handling the challenges addressed above. In this thesis, a framework that integrates ATE and system constraints into test stimulus generation and test response extraction is presented for the efficient production testing of high-performance RF devices using specification-based alternate tests. The main components of the presented framework are as follows: Constraint-driven RF alternate test stimulus generation: An automated test stimulus generation algorithm for RF devices that are evaluated by a specification-based alternate test solution is developed. The high-level models of the test signal path define constraints in the search space of the optimized test stimulus. These models are generated in enough detail such that they inherently define limitations of the low-cost ATE and the I/O restrictions of the device under test (DUT), yet they are simple enough that the non-linear optimization problem can be solved empirically in a reasonable amount of time. Feature extractors for BIT: A methodology for the built-in testing of RF devices integrated into SOPs is developed using additional hardware components. These hardware components correlate the high-bandwidth test response to low bandwidth signatures while extracting the test-critical features of the DUT. Supervised learning is used to map these extracted features, which otherwise are too complicated to decipher by plain mathematical analysis, into the specifications under test. Defect-based alternate testing of RF circuits: A methodology for the efficient testing of RF devices with low-cost defect-based alternate tests is developed. The signature of the DUT is probabilistically compared with a class of defect-free device signatures to explore possible corners under acceptable levels of process parameter variations. Such a defect filter applies discrimination rules generated by a supervised classifier and eliminates the need for a library of possible catastrophic defects.Ph.D.Committee Chair: Chatterjee, Abhijit; Committee Member: Durgin, Greg; Committee Member: Keezer, David; Committee Member: Milor, Linda; Committee Member: Sitaraman, Sures

    Trade-Growth Nexus: Turkish Case

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    The aim of this study is to investigate the role of international trade on the economic growth of Turkish economy for the period of 1998-2010. Augmented Dickey Fuller (ADF) and Phillips-Perron (PP) tests indicate that the variables of the study are stationary in their first differences. Granger causality and cointegration techniques were employed to test the direction of causality between gross domestic product, exports and imports. The results suggest that there is bidirectional causality relationship between imports and gross domestic product and one-way causality relationship from gross domestic product to exports. Furthermore, the results also reveal the existence of a one one-way causality relationship from imports to exports. As a conclusion, the findings support “import-led growth” and “growth-driven export” hypotheses for Turkish economy
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