Achieving reliability using behavioural modules in a robotic assembly system

The research in this thesis looks at improving the reliability of robotic as¬ sembly while still retaining the flexibility to change the system to cope with dif¬ ferent assemblies. The lack of a truly flexible robotic assembly system presents a problem which current systems have yet to overcome. An experimental sys¬ tem has been designed and implemented to demonstrate the ideas presented in this work. Runs of this system have also been performed to test and assess the scheme which has been developed.The Behaviour-based SOMASS system looks at decomposing the task into modular units, called Behavioural Modules, which reliably perform the as¬ sembly task by using variation reducing strategies. The thesis work looks at expanding this framework to produce a system which relaxes the constraints of complete reliability within a Behavioural Module by embedding these in a re¬ liable system architecture. This means that Behavioural Modules do not have to guarantee to successfully perform their given task but instead can perform it adequately, with occasional failures dealt with by the appropriate introduction of alternative actionsTo do this, the concepts of Exit States, the Ideal Execution Path, and Alter¬ native Execution Paths have been described. The Exit State of a Behavioural Module gives an indication of the control path which has actually been taken during its execution. This information, along with appropriate information available to the execution system (such as sensor and planner data), allows the Ideal Execution Path and Alternative Execution Paths to be defined. These show, respectively, the best control path through the system (as determined by the system designer) and alternative control routes which can be taken when necessary

Probabilistic geometric grammars for object recognition

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 121-123).This thesis presents a generative three-dimensional (3D) representation and recognition framework for classes of objects. The framework uses probabilistic grammars to represent object classes recursively in terms of their parts, thereby exploiting the hierarchical and substitutive structure inherent to many types of objects. The framework models the 3) geometric characteristics of object parts using multivariate conditional Gaussians over dimensions, position, and rotation. I present algorithms for learning geometric models and rule probabilities given parsed 3D examples and a fixed grammar. I also present a parsing algorithm for classifying unlabeled, unparsed 3D examples given a geometric grammar. Finally, I describe the results of a set of experiments designed to investigate the chosen model representation of the framework.by Margaret Aida Aycinena.S.M

Agricultural Technology Assessment for Smallholder Farms in Developing Countries: An Analysis using a Farm Simulation Model (FARMSIM)

The rural population in developing countries depends on agriculture. However, in many of these countries, agricultural productivity remains low with episodes of famines in drought-prone areas. One of the options to increase agricultural productivity is through adoption and use of improved agricultural technologies and management systems. Being a relatively high risk business due to factors related to production, marketing and finance, agriculture requires to devise risk mitigating strategies. Several models used to evaluate the adoption of agricultural technologies focus mainly on assessing the ex-post impact of technology without necessarily quantifying the profit and risk associated with the adoption of technologies. This paper introduces a farm simulation model (FARMSIM) that attempts to evaluate the potential economic and nutritional impacts of new agricultural technologies before they are adopted (ex-ante). FARMSIM is a Monte Carlo simulation model that simultaneously evaluates a baseline and an alternative farming technology. In this study, the model is used to analyze the impact of adoption of small scale irrigation technologies and fertilizers on the farm income and nutrition of smallholder farmers in Robit kebele, Amhara region of Ethiopia. The farming technologies under study comprise water lifting technologies (pulley and tank, rope and washer pump, gasoline/diesel motor pump and a solar pump) and use of fertilizers. The key output variables (KOVs) are the probability of positive annual net cash income and ending cash reserves, probability of positive net present value and a benefit cost ratio greater than one. For nutrition, the KOVs relate to the probability of consumption exceeding average daily minimum requirements of an adult for calories, protein, fat, calcium, iron, and vitamin A. The application of recommended fertilizers on grain and vegetable crops, alongside the use of irrigation to grow vegetables and fodder using a motor pump had the highest net present value compared to other scenarios. Similar results were observed for the net cash farm income and the ending cash reserves. However, the most feasible and profitable scenario is the one under the pulley system which had the highest benefit cost ratio. Solar pump system had the lowest benefit cost ratio due most likely to high initial investment cost. As for the nutrition, the simulation results show an increase in quantities available to the farm family of all nutrition variables under all alternative scenarios. However, the daily minimum requirements per adult equivalent were met only for calories, proteins, iron and vitamin A but deficiencies were observed for fat and calcium

Agricultural Technology Assessment for Smallholder Farms in Developing Countries: An Analysis using a Farm Simulation Model (FARMSIM)

The rural population in developing countries depends on agriculture. However, in many of these countries, agricultural productivity remains low with episodes of famines in drought-prone areas. One of the options to increase agricultural productivity is through adoption and use of improved agricultural technologies and management systems. Being a relatively high risk business due to factors related to production, marketing and finance, agriculture requires to devise risk mitigating strategies. Several models used to evaluate the adoption of agricultural technologies focus mainly on assessing the ex-post impact of technology without necessarily quantifying the profit and risk associated with the adoption of technologies. This paper introduces a farm simulation model (FARMSIM) that attempts to evaluate the potential economic and nutritional impacts of new agricultural technologies before they are adopted (ex-ante). FARMSIM is a Monte Carlo simulation model that simultaneously evaluates a baseline and an alternative farming technology. In this study, the model is used to analyze the impact of adoption of small scale irrigation technologies and fertilizers on the farm income and nutrition of smallholder farmers in Robit kebele, Amhara region of Ethiopia. The farming technologies under study comprise water lifting technologies (pulley and tank, rope and washer pump, gasoline/diesel motor pump and a solar pump) and use of fertilizers. The key output variables (KOVs) are the probability of positive annual net cash income and ending cash reserves, probability of positive net present value and a benefit cost ratio greater than one. For nutrition, the KOVs relate to the probability of consumption exceeding average daily minimum requirements of an adult for calories, protein, fat, calcium, iron, and vitamin A. The application of recommended fertilizers on grain and vegetable crops, alongside the use of irrigation to grow vegetables and fodder using a motor pump had the highest net present value compared to other scenarios. Similar results were observed for the net cash farm income and the ending cash reserves. However, the most feasible and profitable scenario is the one under the pulley system which had the highest benefit cost ratio. Solar pump system had the lowest benefit cost ratio due most likely to high initial investment cost. As for the nutrition, the simulation results show an increase in quantities available to the farm family of all nutrition variables under all alternative scenarios. However, the daily minimum requirements per adult equivalent were met only for calories, proteins, iron and vitamin A but deficiencies were observed for fat and calcium

Methodology for capturing geological and geochemical información in the Mexican Geological Survey (MGS).

The Mexican Geological Survey (MGS), an institution of the Mexican government, has the responsibility to explore thoroughly the national mineral resources, as well as providing the mining industry with all the essential elements to facilitate the exploration, identification and quantification of the mineral resources in Mexico. One of the objectives of the Mexican Geological Survey (MGS) is to generate and provide geological-economic information to facilitate the knowledge about the potential of mineral deposits. With the goals of the MGS in mind, a methodology has been developed to capture geological and geochemical data which includes a Web site and has as its main objective to improve the processes used for the generation of geological mining information. This methodology is based on standardizing the attributes and symbols that each of the information levels must capture; and the development of a Web site to publish the geological-mining information within the capture process, as well as the interaction that takes place between the institution and the geologist who captures and interprets that information. All of these through a Web site where personnel from the institution will be able to observe and make comments about the information, which is in capture process before such is finished. When the research has been concluded, the information published in the Web site can be sent to the database of the institution where gathered data about the finished maps is stored. As a result of the methodology used, it is shown that all layers of information to capture in the field have the same structure, thus allowing the integration of information from multiple layers of areas in a quick way. On the other hand, with the development of the website, it will only exist one version of each level of information, and the information in capturing process can be viewed by the institution staff.El servicio geológico mexicano (SGM), institución gubernamental de México, tiene la responsabilidad de explorar detalladamente las riquezas mineras nacionales, así como la de proveer a la industria minera de todos aquellos elementos indispensables para facilitar la exploración, identificación y cuantificación de los recursos minerales del territorio mexicano. Uno de los objetivos del Servicio geológico Mexicano (SGM) es la generar y proveer información geológico-económica para facilitar el conocimiento del potencial de los yacimientos minerales. Pensando en los objetivos del SGM se ha desarrollado la metodología de captura de información geológica que incluye un sitio Web, tiene como objetivo mejorar los procesos utilizados en la generación de información geológico minera. La metodología consiste en estandarizar los atributos y simbología de cada uno de los niveles de información a capturar; y el desarrollo de un sitio Web que permite la publicación de la información geológico-minera que se encuentra en proceso de captura; así como la interacción que tendrá el personal de la institución con el geólogo que realiza la captura e interpretación de la información geológico-minera, a través de un sitio Web en donde el personal de la institución podrá observar y realizar los comentarios sobre la información que se encuentra en proceso de captura. Al finalizar el proceso de captura del área, la información publicada en el sitio Web podrá ser enviada a la base de datos institucional en donde se almacena la información de los mapas terminados. Como resultado de la metodología se observa que todos los niveles de información a capturar en campo tienen la misma estructura, permitiendo así, la integración de niveles de información de varias áreas de manera rápida; por otra parte, con el desarrollo del sitio Web solo existirá una versión de cada nivel de información, así como, la información que se encuentra en proceso de captura podrá ser consultada por el personal de la institución

Service Quality, Customer Satisfaction and Customer Loyalty in Consumer Electronics E-Tailers: A Structural Equation Modeling Approach

The E-S-QUAL and E-RecS-QUAL scales have been successfully tested in a study by Parasuraman, Zeithaml, and Malhotra (2005). However, E-S-QUAL and E-RecS­ QUAL are newly developed and lack specific application to different types of e-business. This non-experimental, correlational study is the first to examine and explore the relationships among electronic service quality, customer satisfaction, and customer loyalty for consumer electronics e-tailers. Using quota and snowball sampling, participants from the continental United States received e-mail invitations and voluntarily forwarded the e-mail invitations to their friends and family. A total of 276 participants completed the online survey. This study\u27s demographic characteristics included most between the ages of 26 and 35 years (47%), mean age of 35.2, most with graduate degrees (40.6%), and with 40% earning a family income of $75,000 or more. Out of twenty hypotheses (including four sub-hypotheses for H1 and three for H2) in this study, 13 were supported, two were marginally supported, and five were not supported. Findings indicated that electronic service quality was measured by online shoppers\u27 perceptions of service quality of consumer electronic e-tailers through four dimensions of the 17-indicator modified E-S-QUAL (efficiency, system availability, fulfillment, and privacy) . Electronic recovery service quality was measured by online shoppers\u27 perceptions of recovery service quality of consumer electronic e-tailers through two dimensions of modified E-RecS-QUAL (responsiveness and contact, and compensation). Findings also indicated that perceived value and customer satisfaction were two significant variables that mediated the relationships among customer expectations, electronic service quality, customer loyalty, and customer complaints. However, this study also found that electronic service quality and customer expectations had no direct effect on customer satisfaction, but had indirect positive effects on customer satisfaction for consumer electronics e-tailers. Consumer electronics e-tailers\u27 managers could formulate plans to improve service quality and recovery service quality through dimensions of E-S-QUAL and E­ RecS-QUAL. They also could formulate a competitive strategy based on the modified Electronic Customer Satisfaction (e-CS) model to keep current customers and to enhance customer relation management. The limitations and recommendations for future research are also included in this study

The Effect of Users' Work Tasks on Librarians' Database Selection

A recent trend in information searching research is task-based information searching, which views a user's task as a central factor for understanding information-seeking behaviors and designing information retrieval systems. To investigate empirically the role of tasks in information searching, particularly in the business domain, this study analyzes the database selection process used by librarians from the perspective of users' tasks. The first part of the study focused on identifying and characterizing business tasks and the associated questions needed to complete the tasks. An inventory of 30 business tasks and 144 associated business questions was developed through content analysis of Harvard Business School cases and other published materials. The second part of the study explored the influence of tasks on database selection by conducting a survey among business librarians in academic institutions. Nine sets of survey questionnaires were created based on the identified business tasks and questions and each questionnaire, containing a total of five business questions for two to three tasks, was disseminated through a Web-based survey tool. Out of 52 sampled librarians, 29 (56 percent response rate) participated in the study. The survey questionnaires focused on participants' use of tasks and related business questions to determine information types likely to answer the questions, to choose databases, and to determine the criteria used to select the databases. The characteristics of business tasks and questions were analyzed and linked to other elements - information types, database selection criteria, and selected databases - to understand the interplay among all elements in the database selection process. The analysis noted the participants' reliance on users' tasks in various aspects of an information searching process. A database selection process was further modeled to describe how five task or context-related criteria - company size, company type, industry sector, geographical setting, and business stage - influence database selection. The inventory of business tasks and questions, along with the patterns among the elements, set the stage for a task-based database selection system