Relative to other roadway segments, intersections occupy a small portion of the overall infrastructure; however, they represent the location for nearly 41 % of the annual automotive crashes in the United States. Thus, intersections are an inherently dangerous roadway element and a prime location for vehicle conflicts. Traditional safety treatments are effective at addressing certain types of intersection safety deficiencies; however, cumulative traffic data suggests these treatments do not address a large portion of the crashes that occur each year. Intersection Collision Avoidance Systems (ICAS) represent a new breed of countermeasures that focus on the types of crashes that have not been reduced with the application of traditional methods. Incursion systems, a subset of ICAS, are designed to specifically undertake crashes that are a result of the violation of a traffic control device. Intersection Collision Avoidance Systems to address Violations (ICAS-V) monitor traffic as it approaches the intersection through a network of in-vehicle sensors, infrastructure- mounted sensors, and communication equipment. A threat-assessment algorithm performs computations to predict the driver's intended intersection maneuver, based on these sensor inputs. If the system predicts a violation, it delivers a timely warning to the driver with the aim of compelling the driver to stop. This warning helps the driver to avoid a potential crash with adjacent traffic. The following dissertation describes an investigation of intersection approach behavior aimed at developing a threat assessment algorithm for stop-sign intersections. Data were collected at live intersections to gather infrastructure-based naturalistic vehicle approach trajectories. This data were compiled and analyzed with the goal of understanding how drivers approach intersections under various speeds and environmental conditions. Six stop-controlled intersection approaches across five intersections in the New River Valley, Virginia area were selected as the test sites. Data were collected from each site for at least two months, resulting in over sixteen total months of data. A series of statistical analysis techniques were applied to construct a set of threat assessment algorithms for stop-controlled intersections. These analyses identified characteristics of intersection approaches that suggested driver intent at the stop sign. Models were constructed to predict driver stopping intent based on measured vehicle kinematics. These models were thoroughly tested using simulation and evaluated with signal detection theory. The overall output of this work is a set of algorithms that may be integrated into an ICAS-V for on-road testing. / Ph. D.

Made available in DSpace on 2016-04-28T20:16:30Z (GMT). No. of bitstreams: 1 2009 - Vanessa de Magalhaes Ferreira.pdf: 3832895 bytes, checksum: 54d34bf9e767ef211ef5b82de690ac7b (MD5) Previous issue date: 2009-03-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / At Guaiba island (Mangaratiba municipality, south coast of Rio de Janeiro) is located the Association of Marine Maricultores of Mangaratiba s farm. The region has excellent conditions for growth of molluscs bivalves: mild water temperatures, mesotrophic and with good sanitary conditions (under bacteriological aspects). The crop is the main shellfish mussel Perna perna, which feeds mainly phytoplanktonic organisms (microalgae). However, the phytoplankton community may be present harmful microalgae such as dinoflagellates Dinophysis spp. that can produce diarrhoetic toxins. The main diarrhoetic phycotoxin produced by these microalgae is okadaic acid (OA), previously detected in the region and associated with D. acuminata. This phycotoxin is implicated in the syndrome Diarrhoetic Shellfish Poisoning, which affects humans, showing the acute effect gastrointestinal symptoms (vomiting, abdominal pain and diarrhea) and chronic promotion of carcinogenesis in the stomach and intestine. Regarding the animal sanity OA affects the immune system of mussels making them susceptible to pathogens and pollutants. In addition is genotoxic and can lead to loss of genetic biodiversity of P. perna. This effect can generate mutations that compromise the future generations of shellfish can lead to disastrous consequences for the mitiliculture. Dinophysis as planktonic organism, has a limited ability to swim. However, under conditions of stability of the water column the dinoflagellate may attach to certain depths, which may become an aggravating factor in the contamination of shellfish if production of OA. This distribution on the microscale is from the interaction between biotic and abiotic factors. Thus the present work to identify and quantify the Dinophysis species present at Guaiba island and verify whether the formation of density along the water column over a year. Were collected monthly, in high tide, over a vertical profile of 8 meters deep. The microalgae were collected with Van-Dorn bottle and fixed with formalde?do for further work on microscopy. We measured temperature, salinity, Secchi depth. Climatological data of rainfall, intensity and direction of winds were released by Vale. We identified 6 species of Dinophysis: D. acuminata, D. caudata, D. fortii, D. ovum, D. tripos and D. rotundata. The Cluster analysis revealed D. acuminata was dominant (Fitopac v1.6, p <0001), besides being the most frequent and abundant throughout the year. Only the species during summer showed higher cell density (average of 297 c?lulas.l-1, a low relative abundance according literature) in the stratum of 0-4 meters deep, than in the stratum > 4 meters (160 c?lulas.l-1), significantly different from the rest of the year (ANOVA, p <0.0001). D. fortii and D. rotundata were codominant in summer and autumn/winter, respectively. The remaining species occurred as incidental. D. ovum only occurred in summer and this work is the first report of this species in Brazilian waters. Redundancy analysis showed that the hydrological and climatological parameters analyzed only salinity and wind (selected by the Monte Carlo test) explained 11% of the variance of the data distribution of Dinophysis. Although no analysis has been performed for the presence of okadaic acid that all identified species are reported as potential producers of toxins diarrhea. Thus it is necessary for an evaluation of risk for diarrhoetic toxins aimed at animal health and safety to public health in the region. / Na ilha Gua?ba (munic?pio de Mangaratiba, litoral sul do Rio de Janeiro) localiza-se a fazenda marinha da Associa??o de Maricultores de Mangaratiba. O principal molusco cultivado ? o mexilh?o Perna perna, que se alimenta principalmente de organismos fitoplanct?nicos (microalgas). No entanto, na comunidade fitoplanct?nica podem estar presentes microalgas nocivas, como os dinoflagelados Dinophysis spp. que podem produzir toxinas diarr?icas. A principal ficotoxina diarr?ica produzida por essas microalgas ? o ?cido okadaico (AO), j? anteriormente detectado na regi?o e associado ? D. acuminata. Tal ficotoxina encontra-se implicada na s?ndrome Envenenamento Diarr?ico por Moluscos, que acomete humanos, apresentando como efeito agudo sintomatologia gastrintestinal (v?mito, dor abdominal e diarr?ia) e cr?nico promo??o de carcinog?nese no est?mago e intestino. Em rela??o ? sanidade animal o AO afeta o sistema imune dos mexilh?es tornando-os suscept?veis ? pat?genos e poluentes. Al?m disso, ? genot?xico e pode levar ? perda de biodiversidade gen?tica de P. perna. Dinophysis, como todo organismo planct?nico, apresenta uma restrita capacidade de nata??o. No entanto, sob condi??es de estabilidade da coluna d ?gua o dinoflagelado pode agregar-se em determinadas profundidades, o que pode vir a se tornar um agravante na contamina??o de moluscos se houver produ??o de AO. Tal distribui??o em microescala resulta da intera??o entre fatores bi?ticos e abi?ticos. Dessa forma o presente trabalho buscou identificar e quantificar as esp?cies de Dinophysis presentes na ilha Gua?ba, bem como verificar se houve a forma??o de adensamentos ao longo da coluna d ?gua ao longo de um ano. Foram realizadas coletas mensais, ao longo de um perfil vertical de 8 metros de profundidade, sempre na preamar. As microalgas foram coletadas com garrafa Van- Dorn e fixadas com formalde?do para posterior realiza??o de microscopia em campo claro e contraste de fase. Foram mensuradas: temperatura, salinidade, profundidade Secchi. Dados climatol?gicos de pluviosidade, intensidade e dire??o dos ventos foram cedidos pela Cia. Vale. Foram identificadas 6 esp?cies de Dinophysis: D. acuminata, D. caudata, D. fortii, D. cf ovum, D. tripos e D. rotundata. A an?lise de classifica??o revelou que D. acuminata foi dominante (Fitopac v1.6, p<0,001), al?m de ser a esp?cie mais frequente e abundante ao longo de todo o ano. Apenas durante o ver?o a esp?cie apresentou maior densidade celular (m?dia de 297 c?lulas.l-1, uma abund?ncia relativa considerada baixa pela literatura) no estrato de 0-4 metros de profundidade, do que no estrato > 4 metros (160 c?lulas.l-1), significativamente diferente do resto do ano (ANOVA, p<0.0001). D. fortii e D. rotundata foram co-dominantes no ver?o e outono/inverno, respectivamente. As demais esp?cies ocorreram como acess?rias. D. ovum apenas ocorreu no ver?o e o presente trabalho ? o primeiro relato da esp?cie em ?guas brasileiras. An?lise de redund?ncia revelou que dos par?metros hidrol?gicos e climatol?gicos analisados apenas salinidade e vento (selecionadas pelo Teste de Monte Carlo) explicaram 11% da vari?ncia dos dados de distribui??o de Dinophysis. Embora n?o tenha sido realizada an?lise para a presen?a do ?cido okadaico salienta-se que todas as esp?cies identificadas s?o relatadas como potenciais produtoras de toxinas diarr?icas. Dessa forma faz-se necess?rio a realiza??o de uma avalia??o de risco em rela??o ?s toxinas diarr?icas com vistas ? sanidade animal e ? seguran?a para a sa?de p?blica.

Between 2005 and 2010 and across 48 countries, including the United States, an increasing positive correlation emerged between national intellectual capital and gross domestic product per capita. The problem remains organizations operating with increasingly complex knowledge networks often lose intellectual capital resulting from ineffective knowledge management practices. The purpose of this study was to provide management opportunities to reduce intellectual capital loss. The first research question addressed how an enhanced intelligent, complex, and adaptive system (ICAS) model could clarify management's understanding of organizational knowledge transfer. The second research question addressed how interdisciplinary theory could become more meaningfully infused to enhance management practices of the organization's knowledge ecosystem. The nature of this study was phenomenological to gain deeper understanding of individual experiences related to knowledge flow phenomena. Data were collected from a single historical research dataset containing 11 subject interviews and analyzed using Moustakas' heuristic framework. Original interviews were collected in 2012 during research within a military unit, included in this study based on theme alignment. Organizational, knowledge management, emergent systems, and cognition theories were synthesized to enhance understandings of emergent ICAS forces. Individuals create unique ICAS flow emergent force dynamics in relation to micro- and macro-meso sensemaking and sensegiving. Findings indicated individual knowledge work significantly shapes emergent ICAS flow dynamics. Collectively enhancing knowledge stewardship over time could foster positive social change by improving national welfare.

Intelligent conversational agents (ICAs) are artificial intelligence (AI)-enabled systems that can communicate with humans through text or voice using natural language. The first ICA, “Eliza,” appeared in 1966 to simulate human conversation using pattern matching. Commercial ICAs appeared on the AOL and MSN platforms in 2001 and aided in developing advanced AI and Human-Computer Interaction (HCI). Since then, ICAs have progressively appeared in consumer products and services. Their success depends on the user’s experience and attitude towards these services. This research examines customer attitudes towards ICAs through a theoretical framework of integrated Expectation Confirmation Theory (ECT) and Task Technology Fit Theory (TTF). By exploring user experience via an experiment that engages end-users with ICA’s different functions and tasks, this study examines user perception of ICA’s AI capabilities, such as Conversation Ability, Friendliness, Intelligence, Responsiveness, Task Performance, and Trust. This research investigates how customer satisfaction with ICA capabilities and perceived task technology fit influence their intention to use ICAs. A field survey of 380 Canadian end-users utilizing ICAs on the websites of five large Canadian telecom service providers enabled empirical testing of the model. / Thesis / Doctor of Philosophy (PhD)