An experimental analysis of the factors which affect the sensitivity of the Ported Coaxial Cable Sensor (PCCS) system is presented. The measured response profile of the test system is compared against variations of cable separation distance, soil conductivity and permittivity, and magnetic field intensity above the transmitter cable. These experiments show that higher conductivity and permittivity of the burial medium results in a decrease in the strength of the magnetic field above the transmitter cable, and that this results in a decrease in response number. The results of these experiments are compared with the results obtained from a theoretical analysis of a simplified model. An experimentally derived relationship between cable separation distance and response number, which is valid for all soil types, can be applied to predictably minimize variations in sensitivity, resulting in a response ratio for each cell which will not exceed 3:1.

Understanding what variables influence park use would assist park providers and policy makers in acquiring, designing, managing, and funding initiatives which encourage or support park use. Previous studies indicate that access to parks (measured by both objective and perceived distances), park appeal in terms of being well-maintained, and effective communication between constituents and park suppliers, relate positively to park use. This study explores the relationships between access, appeal, and communication and park use. Access is operationalized as four objective distances from household to nearest park using both Euclidian and Network measures, and by subjective self-reported measures of ability to access parks on foot or by bicycle. Appeal is concerned with the influence of parks’ perceived level of maintenance and availability of amenities on the probability of park use. Effective communication is operationalized by three variables: perceptions of being well-informed, being included in the planning process, and being able to give feedback to park leaders. These variables and selected demographic data were extracted from an existing data set: the City of College Station Needs Assessment. Findings indicated that a) respondents with access to parks are more likely to use parks, b) level of maintenance and available amenities influenced use, and c) respondents who are well-informed are more likely to use parks.

This dissertation develops a methodology for automated trajectory control of a spacecraft about a non-maneuvering target. The methodology utilizes relative orbital elements (ROEs), combined with guidance laws based upon artificial potential functions (APFs), to perform automated trajectory planning and maneuver design. The investigation provides a definitive reference on the definition and use of ROEs for relative proximity operations. The detailed derivation of ROEs is provided, along with transformations between ROEs and relative Cartesian state elements, characteristics of unforced motion in terms of ROEs, and the effect of impulsive maneuvers on ROEs. Operationally-useful guidance algorithms utilizing ROEs are developed and demonstrated. These ROE-based algorithms for rendezvous, circumnavigation and station-keeping provide a toolkit for relative proximity operations mission planning. A new approach for APF formulation using ROEs as the target variables is developed. While previous approaches allowed targeting of a specified relative position, the present approach allows the targeting of relative orbit geometries. The approach capitalizes upon the orbital dynamics represented through the ROEs, and retains the computational simplicity offered by the APFs. Formulations for the APF targeting of individual ROEs, as well as simultaneous targeting of a set of ROEs, are established. An approach for combining ROE targeting using APFs with obstacle avoidance is presented. The trajectory guidance algorithm performance is evaluated using a flight-like guidance, navigation and control simulation environment, including orbital perturbations. Algorithm performance is established through a set of operationally relevant scenarios. The guidance algorithms are shown to be capable of correcting for environmental disturbances, while meeting the targeted relative orbits in an automated fashion.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 95-100). Also available via the Internet.

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This thesis contributes to recent theorizations in economic geography on the effects of proximity on firm competitiveness. One of the great challenge in the contemporary economy is for firms to remain competitive. Their innovative ability is highly dependent on the knowledge they possess and their ability to acquire new knowledge. It is argued that a relational proximity between individuals reduces uncertainty and offers a joint platform for communication and learning. Therefore, does this thesis apply a micro-perspective in which the labor force and the knowledge composition within plants is examined. The aim is pursued by exploring the interrelationship between different types of proximity in the labor force and plant performance. The proximity dimensions under scrutiny are; the cognitive-, the organizational-, and the geographical proximity dimension. The three empirical papers in the thesis are based on longitudinal micro-data from the database ASTRID. The database connects detailed socio-economic data of individuals to features of plants and firms in the entire Swedish economy. The empirical findings suggest that the different types of proximities are interdependent with regard to learning in firms. The interdependence is manifested through the variable impact on plant performance that a given distance in one dimension has, depending on what other type of proximity is accounted for at the plant. It is further found that the proximity dimensions have conditional effects on learning and innovation in firms. The empirical findings also indicate that the circumstances under which learning and knowledge application take place, vary between capital-intensive and labor-intensive sectors. Moreover, it is found that relatedness in the cognitive dimension is not unambiguously positive for interactive learning and innovativeness. Similarity in one dimension and unrelatedness in the cognitive dimension, has a significantly stronger impact on interactive learning than simply having relatedness in the cognitive dimension. It therefore seems as if the combined distance of several proximity dimensions should be taken into account when estimating the innovative power of a firm or industry. When the empirical findings are considered together it is evident that the local environment generates relational proximity between agents through formal- and informal networks. This proximity reproduces and rejuvenates the localized capabilities by allowing for the combination of heterogeneous pieces of knowledge in firms through local unrelated labor inflow. In conclusion, time and place are the paramount dimensions that shape the micro-dynamics of knowledge generation and innovation in firms.

This thesis argues that the concept of spatial proximity offers a viable and practical option for the development of context-aware systems for highly mobile and dynamic environments. Such systems would overcome the shortcomings experienced by today’s location-based and infrastructure dependent systems whose ability to deliver context-awareness is prescribed by their infrastructure. The proposed architecture will also allow for scalable interaction as against the single level of interaction in existing systems which limits services to a particular sized area. The thesis examines the concept of spatial proximity and demonstrates how this concept can be exploited to take advantage of technological convergence to offer mobility and scalability to systems. It discusses the design of a proximity-based system that can deliver scalable context-aware services in highly mobile and dynamic environments. It explores the practical application of this novel design in a proximity-sensitive messaging application by creating a proof-of-concept prototype. The proof-of-concept prototype is used to evaluate the design as well as to elicit user views and expectations about a proximity-based approach. Together these provide a valuable insight into the applicability of the proximity-based approach for designing context-aware systems. The design and development work discussed in the thesis presents a Proximity-Sensitive System Architecture that can be adapted for a variety of proximity-sensitive services. This is illustrated by means of examples, including a variety of context-aware messaging applications. The thesis also raises issues for information delivery, resource sharing, and human-computer interaction. While the technological solution (proximity-based messaging) offered is only one among several that can be developed using this architecture, it offers the opportunity to stimulate ideas in the relatively new field of proximity and technological convergence research, and contributes to a better understanding of their potential role in offering context-aware services.

The purpose of this study is to deepen the understanding of cultural implications in the trade of telenovelas within Latin America. After performing a literature review on the trade of TV products, it was founded that Chile has been buying the format of Argentinean telenovelas in order to reproduce them for the Chilean audience. From the perspective of cultural proximity (Straubhaar, 1991), it could be expected to see Chile broadcasting the original version of the Argentinean telenovelas, as these countries share a similar cultural background, language, et cetera. However, that is not the case. Additionally, it was found that the Argentinean accent is not welcomed in countries north to Ecuador (Waisbord, 2004) because of cultural reasons. In order to grasp the role of accents and other cultural factors in these situations, 4 focus groups were organized with participants of 12 Latin American countries, who were inquired about the accents and cultural contents of the Argentinean telenovela “LaLola”, which’s format was bought by Chile. However, its original canned version reached markets beyond Ecuador. Besides Spanish accents, other variables were introduced to the study to assess if they influence audiences’ perception of foreign telenovelas. These variables are political, historical and territorial quarrels between countries, national images about the country of origin of the telenovela, and discrimination by nationality. The results showed that the perception of accents is connected to national images, which are constructed both on historical political quarrels and ethnic chauvinism based on nationality. Indeed, historical and political problems, as well as discrimination on the basis of nationality are, in the case of Bolivia and Chile, sources of negative images that affect how viewers interpret the Argentinean intonation. Moreover, it was found that a country with a good reputation, as well as a positive image and perception within the region, seem to improve the reception of that country’s accent and its chances of selling its telenovelas abroad. The findings also indicated that local culture is of great importance for audiences. In this scenario, the concept of geo-linguistic region as the primary factor in predicting viewing preferences appears to be over-simplistic.

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