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A Comparison of Agent-Oriented Software Engineering Frameworks and MethodologiesLin, Chia-En 12 1900 (has links)
Agent-oriented software engineering (AOSE) covers issues on developing systems with software agents. There are many techniques, mostly agent-oriented and object-oriented, ready to be chosen as building blocks to create agent-based systems. There have been several AOSE methodologies proposed intending to show engineers guidelines on how these elements are constituted in having agents achieve the overall system goals. Although these solutions are promising, most of them are designed in ad-hoc manner without truly obeying software developing life-cycle fully, as well as lacking of examinations on agent-oriented features. To address these issues, we investigated state-of-the-art techniques and AOSE methodologies. By examining them in different respects, we commented on the strength and weakness of them. Toward a formal study, a comparison framework has been set up regarding four aspects, including concepts and properties, notations and modeling techniques, process, and pragmatics. Under these criteria, we conducted the comparison in both overview and detailed level. The comparison helped us with empirical and analytical study, to inspect the issues on how an ideal agent-based system will be formed.
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Synthesis of silver doped titanium dioxide nanocomposites using tea extract from Aspalathus linearis and evaluation of their antibacterial effects.Kobese, Nokubonga January 2018 (has links)
>Magister Scientiae - MSc / Despite the wide success of antimicrobial agents against waterborne pathogens, waterborne disease continues to pose a threat to both mankind and animals. A major concern is that certain bacteria have developed resistance to antimicrobial agents, as a result of their overuse. Silver (Ag) nanoparticles are widely used for antibacterial purposes such as medical dressings. However, they are highly toxic to human cells. Hence, there is a great interest in developing next generation antibacterial nanoparticles that are as effective as Ag nanoparticles for antibacterial functions, while having less toxicity to human cells. Several methods can be used to generate these antimicrobial nanoparticles, one of which is green nanotechnology. Green nanotechnology uses natural plants such as tea to synthesise nanoparticles rather than chemicals, thus reduce human and animal harm and improve sustainability of antibacterial agents.
Silver-titanium nano-composites (Ag-TiO2 NCs) were synthesised with the hydrothermal method using a tea extract from Aspalathus linearis (Rooibos, RB), and distilled water in the presence of nitrogen. The resulting structures were characterised with high resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS) analysis X-Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). The antibacterial characteristics of these new NCs were evaluated against 3 bacteria: Bacillus cereus, Cupriavidus metallidurans, and Escherichia coli.
The optimum processing conditions to produce 6-nm spherical NPs included maintaining the temperature at 90 °C, the pH at 4.35, and using RB extract at a concentration of 2 mg/mL. The size of silver NPs was reduced in acidic conditions, agglomerated in neutral conditions, and highly reduced in alkaline conditions. Increasing the pH decreased the particle size and narrowed the particle size distribution.
Gram-positive B. cereus showed slight resistance or tolerance to the Ag-TiO2 nanocomposite compared to the gram-negative bacteria E. coli and C. metallidurans. The treatment concentration required for total inhibition of E. coli and C. metallidurans growth was 100 mg/mL. Supported silver nanoparticles has shown to be a suitable way to obtain highly dispersed silver over higher surface area. This approach allowed Ag-TiO2 nanocomposite to be an efficient bactericide, with less silver amount employed.
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Political Poison: Agent Orange in Congress 1940-1991Webb, Jamie Pauline 01 May 2019 (has links)
This paper examines the evolution of government policy through Congressional debate and citizen involvement on the topic of Agent Orange. Use of primary sources from newspaper and journal articles, Congressional records, scientific studies, and press releases and some secondary literature by scholars from multiple disciplines builds a picture of the ongoing debate of Agent Orange and its two component herbicides from circa 1940 to 1991. Within this paper are four primary focuses, divided into three parts. First, the Congressional discussions prior to 1970 of 2,4-D and 2,4,5-T, the two herbicides that comprise Agent Orange. Second and third, discussed in the same section, the involvement of the scientific community and the ratification of the Geneva Protocol. Lastly, the movement after the Vietnam War for veteran benefits due to Agent Orange exposure.
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Designing a realistic virtual bumblebeeMarsden, Timothy 09 February 2016 (has links)
Optimal Foraging Theory is a set of mathematical models used in the field of behavioral ecology to predict how animals should weigh foraging costs and benefits in order to maximize their food intake. One popular model, referred to as the Optimal Diet Model (ODM), focuses on how individuals should respond to variation in food quality in order to optimize food selection. The main prediction of the ODM is that low quality food items should only be accepted when higher quality items are encountered below a predicted threshold. Yet, many empirical studies have found that animals still include low quality items in their diet above such thresholds, indicating a sub-optimal foraging strategy. Here, we test the hypothesis that such ‘partial preferences’ are produced as a consequence of incomplete information on prey distributions resulting from memory limitations. To test this hypothesis, we used agent-based modeling in NetLogo to create a model of flower choice behavior in a virtual bumblebee forager (SimBee). We program virtual bee foragers with an adaptive decision-making algorithm based on the classic ODM, which we have modified to include memory. Our results show that the probability of correctly rejecting a low quality food item increases with memory size, suggesting that memory limitations play a significant role in driving partial preferences. We discuss the implications of this finding and further applications of our SimBee model in research and educational contexts.
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Designing a realistic virtual bumblebeeMarsden, Timothy 09 February 2016 (has links)
Optimal Foraging Theory is a set of mathematical models used in the field of behavioral ecology to predict how animals should weigh foraging costs and benefits in order to maximize their food intake. One popular model, referred to as the Optimal Diet Model (ODM), focuses on how individuals should respond to variation in food quality in order to optimize food selection. The main prediction of the ODM is that low quality food items should only be accepted when higher quality items are encountered below a predicted threshold. Yet, many empirical studies have found that animals still include low quality items in their diet above such thresholds, indicating a sub-optimal foraging strategy. Here, we test the hypothesis that such ‘partial preferences’ are produced as a consequence of incomplete information on prey distributions resulting from memory limitations. To test this hypothesis, we used agent-based modeling in NetLogo to create a model of flower choice behavior in a virtual bumblebee forager (SimBee). We program virtual bee foragers with an adaptive decision-making algorithm based on the classic ODM, which we have modified to include memory. Our results show that the probability of correctly rejecting a low quality food item increases with memory size, suggesting that memory limitations play a significant role in driving partial preferences. We discuss the implications of this finding and further applications of our SimBee model in research and educational contexts.
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Erosive cola-based drinks affect the bonding to enamel surface: an in vitro studyCasas-Apayco, Leslie, Dreibi, Vanessa Manzini, Hipólito, Ana Carolina, Graeff, Márcia Sirlene Zardin, Rios, Daniela, Magalhaes, Ana Carolina, Buzalaf, Marília Afonso Rabelo, Wang, Linda 04 August 2014 (has links)
Objective: This study aimed to assess the impact of in vitro erosion provoked by different cola-based drinks (Coke types), associated or not with toothbrushing, to bonding to enamel. Material and methods: Forty-six bovine enamel specimens were prepared and randomly assigned into seven groups (N=8): C- Control (neither eroded nor abraded), ERO-RC: 3x/1-minute immersion in Regular Coke (RC), ERO-LC: 3x/1-minute immersion in Light Coke (LC), ERO-ZC: 3x/1-minute immersion in Zero Coke (ZC) and three other eroded groups, subsequently abraded for 1-minute toothbrushing (EROAB-RC, EROAB-LC and EROAB-ZC, respectively). After challenges, they were stored overnight in artificial saliva for a total of 24 hours and restored with Adper Single Bond 2/Filtek Z350. Buildup coronal surfaces were cut in 1 mm2-specimens and subjected to a microtensile test. Data were statistically analyzed by two-way ANOVA/Bonferroni tests (a=0.05). Failure modes were assessed by optical microscopy (X40). The Interface of the restorations were observed using Confocal Laser Scanning Microscopy (CLSM). Results: All tested cola-based drinks significantly reduced the bond strength, which was also observed in the analyses of interfaces. Toothbrushing did not have any impact on the bond strength. CLSM showed that except for Zero Coke, all eroded specimens resulted in irregular hybrid layer formation. Conclusions: All cola-based drinks reduced the bond strength. Different patterns of hybrid layers were obtained revealing their impact, except for ZC. / This study was supported in part by grants given by the São Paulo Research Foundation (FAPESP), Process no. 2009/14986-0, and the National Council for Scientific and Technological Development (CNPq), Process no. 480038/2007-4. In Addition, this study was performed by V.D.M. and A.C.H. as fulfillment of their graduation research, which was supported by FAPESP (Processes no. 2009/01376-9 and 2009/01377-5, respectively). The authors are also grateful to Oral B and SDI, which donated the materials used in the study. / Revisión por pares
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Consumer Search and Its Implications for Market CompetitionsWong, Yat Fung January 2015 (has links)
Thesis advisor: Hideo Konishi / This dissertation covers three essays in modelling the market competitions with the presence of consumer search. The first two essays add on Wolinsky's (1986) model to investigate firms' optimal choice of their way of doing business in response to the changing consumer search behaviors during the information age. The third essay modifies the Varian's (1980) model to provide a new mechanism to rationalize the countercyclical markups in supermarkets. The first essay concerns the formation of referral alliance. It extends the Wolinsky's (1986) model to a three-stage game with two types of products produced by a continuum of firms with each one having strength in a single type only. In the first stage, firms simultaneously decide on the formation of referral alliances, in which each alliance consists of a pair of firms producing different types of products. In the second stage, they set price simultaneously. In the third stage, each consumer who only values one type of product searches sequentially for the right product. We show that firms with low ability to deal with the unmatched consumers are positively assorted together in the formation of referral alliance with multiple equilibrium possible. The proliferation of referral alliance always benefits consumers but not necessarily firms. One the one hand, it intensifies competition and drives down the market price. On the other hand, it increases the mass of consumers participating in the search market. The price elasticity of demand together with our stability condition govern the changes in consumer and social welfare as the search cost varies. The reduction in search cost always increases consumer and social welfare only if the equilibrium is stable with elastic demand. The policy implication from our results is that it might be more effective to improve consumer and social welfare by inducing more firms to participate in the referral alliances rather than reducing the consumers' search cost. The second essay studies the incentives for stores to invest effort in serving customers if effort is costly and might be merely persuasive that reduces consumption utility. We incorporate a sales agent to each store in Wolinsky's (1986) model, in which the sales agent is paid either by fixed wage or by commissions. The commissions motivate sales agents to provide more advice, which could be indeed useful to increase clients' willingness to pay or merely persuasive without affecting it. Consumers are sophisticated that understand the dual roles of effort before visiting firms, but they might be impressionable and therefore could not stay away from the effect of persuasion when they are making the purchasing decision. When consumers are heterogeneous in terms of their impressionability, they are sorted into stores with fixed wage and commissions in the equilibrium. The composition of stores varies with the search cost and the ability of sales agents to increase consumers' willingness to pay (effectiveness of advice). When the advice is relatively ineffective, there will be an increase in mass of fixed wage stores in response to a reduction in search cost. The reverse is true when the advice is sufficiently effective. Additionally, the mass of fixed wage stores always increases as the advice becomes less effective. The competitive equilibrium outcome might imply that there are too little commission-based stores, so it could be social welfare enhancing by encouraging more consumers to visit the stores with commissions. The third essay provides a simple mechanism that rationalizes the countercyclical markups in supermarkets with the presence of a warehouse club. We first provide a mechanism on the higher supermarket prices upon the entry of the warehouse club. The new warehouse club attracts price-sensitive consumers away from supermarkets, which reduces the price elasticity of the consumers in the supermarket regime. This relaxes price competition resulting in higher supermarket prices. After that we apply the same mechanism to explain the countercyclical markups in supermarkets. During economic booms, the time value of consumers increases making them less willing to visit the warehouse club. Thus, economic booms increase the amount of price-sensitive consumers in supermarkets, intensifying price competition and inducing a lower price relative to cost in booming times. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.
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The Early 13th Century Latin-Augustinian Reception of the Peripatetic Agent Intellect and the Historical Constitution of the SelfRobinson, Matthew January 2012 (has links)
Thesis advisor: Jean-Luc Solère / This dissertation examines the noetics of several early thirteenth-century Latin Augustinian thinkers, who first received Aristotle's noetic from the Arabs, examining in detail the early Latin reception of Aristotelian proposal that human thought is caused by the `agent intellect'. I argue that the early Latin-Augustinian reactions to the Arab noetics reveal an abiding Latin commitment to a concept of selfhood in natural thought. For different reasons, these early 13th century Latin thinkers explicitly locate the principle of natural thought within the individual's soul, thus conceiving the individual as the spontaneous origin of the activity of his or her thinking. I propose that there is a progressively more refined development of this concept within the interpretation of the Peripatetic noetic proposed within the early 13th century Franciscan school. I trace this development through John of La Rochelle to the anonymous author of the Summa Fratris Alexandri Book 2 to Bonaventure's early thought. At the same time, I analyze this Franciscan development relative to William of Auvergne's well-conceived opposition to all interpretations of the Aristotelian noetic. I make the case that William's critique sets the standard for the noetic of the individual to which these Franciscans adhere, even in their adoption of the Aristotelian noetic. I then argue that to adhere to William's standard, these Franciscans drew on Averroes' account of the agent intellect as found in Averroes' Commentarium Magnum in Aristotelis De Anima Libros. Finally, I argue that within the early 13th century's development of the noetic of the individual, there is an important, self-conscious development of the historico-philosophical concept of the Western self. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Philosophy.
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Nanopartículas antiferromagnéticas de MnO para aplicações em biomedicina como agentes de contraste / Antiffeomagnetic MNo nanoparticles for applications in biomedicine as a contrast agentNeves, Herbert Rodrigo 24 February 2012 (has links)
Nanomateriais têm sido amplamente estudados, como resultado de suas propriedades físicas e químicas diferenciadas, que oferecem um grande número de possibilidades para aplicações em biomedicina, principalmente na terapia de câncer e no desenvolvimento de estratégias de diagnóstico não invasivo. O óxido de ferro superparamagnético (SPION) é o principal material estudado como agente de contraste para imagem por ressonância magnética, devido à sua capacidade de reduzir o tempo de relaxação transversal (T2) em diferentes tecidos e sua menor toxicidade que os complexos de Gd3+ e Mn2+ usados atualmente. Entretanto, o acumulo de SPIONs pode ser facilmente confundido com sinais referentes à calcificação, depósito de metais pesados e sangramentos, e a alta susceptibilidade magnética do material promove distorções na imagem. Assim, alguns aspectos são desejáveis em material para que este tenha potencial para substituir o SPION, tais como forma nanoparticulada, para fácil modificação de superfície e possibilidade de funcionalização com agentes biosseletivos, e contraste positivo em T1. As nanopartículas (NPs) antiferromagnéticas de MnO atendem a todos os requisitos necessários para substituir o óxido de ferro. As NPs de MnO foram sintetizadas a partir da decomposição térmica do acetilacetonato de manganês(II) em uma variação do método poliol modificado, resultando na formação de NPs com tamanho médio de 21 ± 3,9 nm. Foi realizada a substituição de ligantes de superfície para que se substituísse o ácido oleico adsorvido sobre o material por 3-aminopropiltrimetoxisilano (APTMS) e foi determinada a concentração de grupamentos amino sobre a superfície das NPs. Posteriormente, obteve-se uma estrutura do tipo \"core/shell\" dispersível em meio aquoso e biocompatível pela reação dos grupos amino livres com o carboxilato da carboximetil dextrana (CMDex). O potencial de superfície e a estabilidade coloidal das NPs funcionalizadas foram caracterizados por mobilidade eletroforética e por espalhamento de luz dinâmico em água deionizada e em condições que mimetizavam o sangue. As NPs apresentaram toxicidade em células cancerosas de carcinoma cervical humano (HeLa). Entretanto, não foi observada toxicidade significativa na linhagem de células não cancerosas NCTC clone L929. Tanto as NPs como sintetizadas quanto as recobertas com CMDex apresentaram controle de tamanho e forma, apresentando distribuição de tamanho compatível com o esperado para as aplicações em biomedicina. / Nanomaterials have been widely studied as a result of their interesting physical and chemical properties, which offer a large number of possibilities for applications in biomedicine mainly in cancer therapy and the development of strategies for non-invasive diagnosis. The superparamagnetic iron oxide nanoparticles (SPION) is the main studied material as contrast agent for magnetic resonance imaging (MRI) due to its ability to reduce the transverse relaxation time (T2) in different tissues and lower toxicity than Gd3+ and Mn2+ complexes currently used. However, this SPIONs accumulation can be confused with signals from calcification, bleeding or metal deposits, and the high magnetic susceptibility distorts the background image because its ferromagnetic behavior. Some aspects are desirable to replace SPIONs, such as nanoparticulate form for simple surface modification and labeling with targeting agents, and positive longitudinal T1 relaxation time contrast ability. The antiferromagnetic MnO NPs attend all these requirements and overcome the drawback of using SPION. In our study, MnO NPs were synthesized by the thermal decomposition of Mn(II) acetylacetonate by a variation of the modified polyol process resulting in spherical nanoparticles with average size of 21 ± 3,9 nm. The ligand-exchange step was used to replace the oleic acid adsorbed on the as-synthesized NPs surface by 3-aminopropyltriethoxysilane (APTMS) and the total free amine groups on the NPs surface was determined. After that, a biocompatible and water-dispersible core/shell structure was obtained by coating with carboxymethyl dextran (CMDex) using the free amine-terminal group from APTMS and the carboxylate groups present in the CMDex molecules conjungation. Surface potential and colloidal stability of these functionalized NPs were evaluated by electrophoretic mobility and dynamic light scattering techniques in both water and artificial blood by using the Simulated Body Fluid (SBF) medium. While the water-dispersible NPs have shown toxicity in the human cell line derived from cervical cancer (HeLa), they have not shown significantly cytotoxicity in the healthy fibroblast cells (cell line L929). Both the as-synthesized and coated NPs present controlled size and shape and the final NPs size distribution and magnetic properties are compatible with the expected for biomedical applications.
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Product diversification in an artificial strategy environmentBauer, Roland, Schwingenschlögl, Albert, Vetschera, Rudolf January 2003 (has links) (PDF)
The paper studies the impact of a diversification vs. a core-competence oriented strategy using an agent-based simulation model. The aim of the paper is twofold: first, we analyze whether agent-based models are a viable tool for analyzing questions related to corporate strategy. We show that standard results from the strategy literature can indeed be reproduced and refined by using this type of models. Second, the agent-based model allows us to formulate more precise hypotheses and more precisely delineate the scope of situations in which standard results from the strategy literature apply. For the problem of diversification analyzed in this paper, the results from the agent-based simulation lead to the conclusion that in addition to environmental dynamics, overall market size is also an important factor, which was not considered in the previous literature. / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"
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