Firm friends: Examining functions and outcomes of workplace friendship among law firm associates
description- – The workplace is increasingly becoming an important venue for social connection and friendship. Workplace friendships present a unique blurring of public and private life spheres, and the idea of a"work friend"implies integrating the voluntary and non-institutionalized role of friend with the more involuntary and formalized role of coworker. Although the workplace friendship phenomenon has been widely publicized in the popular press and business media, limited academic research has focused specifically on friendships that are developed and maintained in the work environment. Drawing on research in the areas of interpersonal relationships, friendship, developmental relationships, high-quality connections at work, and social support, this dissertation research explored workplace friendship among a particular professional population, associates working in private practice law firms, and was organized as a two-part study combining qualitative and quantitative methodologies. Phase one, the qualitative study, used interview data to identify functions that workplace friendships serve and outcomes associated with the existence of workplace friendships. Qualitative findings showed that workplace friendships offer individuals companionship, work assistance, understanding, and emotional support, and are associated with the outcomes of well-being, job satisfaction, turnover intentions, and productivity. These qualitative findings were integrated with existing research to develop a conceptual model and hypotheses related to workplace friendship. Phase two, the quantitative study, used survey data to test this conceptual model and related hypotheses. More specifically, the quantitative study tested relationships among the opportunity for workplace friendship, the functions of companionship, work assistance, understanding, and emotional support, and the outcomes of well-being, job satisfaction, turnover intentions, and productivity. Additionally, the quantitative study assessed the impact of role conflict in affecting the relationship between workplace friendship and these outcome variables. Quantitative findings showed that individuals' perceptions of having friendship opportunities in the workplace affected both the functions and outcomes of workplace friendships. In addition, workplace friendship functions were directly associated with individuals' reported attitudinal and behavioral outcomes; however, this relationship was not moderated by respondents' experience of role conflict in their friendship relations. Overall, these findings suggest that workplace friendship plays a significant role in affecting individuals' work experience.
- – 2007-01-01
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Individual and relational dynamics of ambition in careers
description- – Ambition has long been heralded as essential for career success, yet few researchers have explored this concept empirically. Management scholars have primarily defined ambition as the desire to get ahead, an extrinsic goal. Based on the changing nature of careers, the theory developed here explores the concept of ambition from a social cognitive perspective. The study investigates the dynamics of individual differences and developmental (mentoring) relationships with ambition and career success. To test the conceptual model, ambition is operationalized as both intrinsic and extrinsic aspirations. Data collection for this project includes a survey of 223 young professionals and 20 follow-up interviews. Contrary to expectations, disposition was directly associated with objective success, subjective success, and well-being rather than mediated through ambition. Career identity salience was positively associated with extrinsic aspirations which were then linked to objective success; however, it was negatively associated with well-being. Findings support the conceptualization of ambition as a multi-faceted construct, with extrinsic components associated with objective success and intrinsic components associated with both objective and subjective outcomes. The relationship between ambition and support from developmental networks is complex. Quantitative data indicate developmental network size and support is associated with intrinsic aspirations and well-being. Consistent with this, individuals described personal relationships as predictors of ambition. However professional relationships seemed to affect their ambition through a more iterative process suggesting a feedback loop between these two variables. Post-hoc analyses reveal gender differences in the expression of ambition. Men rank the desire for financial rewards, an extrinsic aspiration, as most important while it is fourth for women following intrinsic factors. Further analyses of developmental network data reveal that support from personal sources has a stronger relationship with both objective and subjective success than that from work-based relationships. This study was the first to examine the association of developmental network composition and support with ambition in a population of working adults. The findings disentangle the relative influence of extrinsic and intrinsic ambition on objective and subjective career success. By incorporating self-determination theory into its conceptual framework the study also makes a unique theoretical and empirical contribution to the research on careers.
- – 2007-01-01
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Quality evaluations and their impacts: The roles of legitimacy and significance
description- – Previous research in the areas of institutional quality assessment and also total quality management has paid little attention to the role of cognition and focused more on how to create better evaluation systems or how quality programs improve organizational performance. In this dissertation, I have built on previous research on organizational change and cognition to shed new light on quality assessments in universities. Within the context of periodical program quality evaluations in universities, I assessed the effects of several antecedents on faculty perceptions of evaluations' legitimacy and significance, and tested their mediating role in the formation of faculty attitudes towards a future re-evaluation. I found that faculty identification with their program led them to rate the legitimacy and significance of evaluations more highly. In addition, faculty who belonged to the humanities and social sciences were more likely to perceive evaluations as legitimate than were faculty in the technical and natural sciences. The fidelity of the past evaluation to the model developed by the Evaluation Agency did not have any effect on faculty perceptions of evaluations. Perceptions of the legitimacy and significance of evaluations partially mediated the effect of identification with the program on attitude towards a future re-evaluation, although in the case of legitimacy this mediation was only marginally significant, and perceived legitimacy moderated the impact of perceived significance on attitude towards a future re-evaluation. I conclude that faculty perceptions of evaluations and their attitude towards them depend on their level of identification with the program under evaluation. This research contributes to the extant literature on quality evaluations. First, it shows that faculty attitudes towards a future re-evaluation are partially mediated by their perceptions of evaluations' significance and more weakly by their perceptions of evaluations' legitimacy. Second, faculty identification positively affects their perceptions of program evaluations and their attitude towards a future re-evaluation. Third, it shows that the fidelity of the last evaluation process to the Evaluation Agency model does not affect faculty perceptions of evaluations. Finally, my study indicates that faculty perceptions of evaluations' legitimacy and significance interact to shape faculty attitudes towards a future re-evaluation.
- – 2007-01-01
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Conceptualizing the sexualization of girlhood through online public discourse
description- – Research examines public concern in order to conceptualize the sexualization of children. Inductive content analysis was used to examine online public discourse in discussion forums, blogs, and comments posted to blogs around the sexualization of children. Discourse focused on sexualization as driven by media and corporate forces, but primarily parents, who are expected to control the visually-cued identity message constructed by the presentation of the girl's body in clothing, leisure pursuits, and images. Anxiety was related to people's reliance on visual signals as markers of childhood/adulthood, sexual availability, and social class, and was also revealed in protection narratives. Conceptualization was further informed by private vs. public gaze distinction, and a narrow range of prescribed, sexually objectifying consumer choices. Themes around economic, cultural, and gender structures of power are explored and future research is suggested.
- – 2007-01-01
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Effect of tectonic environment on the extent to which seismicity delineates zones where future large earthquakes tend to occur
description- – The spatial distribution of seismicity is often used as an indicator of zones where future large earthquakes are likely to occur. This is particularly true for intraplate regions, where geology is more enigmatic in terms of delineating seismically active areas. In this study, we investigate whether this tendency for future earthquakes to occur near past earthquakes can be treated as a real, measurable, physical phenomenon. The goal of this study is to systematically investigate the tendency for past seismicity to delineate zones where future large earthquakes are likely to occur. The method used is called"cellular seismology"and it involves constructing circular zones of a given radius around each epicenter in a past earthquake catalog. The percentage of future earthquakes that occurred within these circular zones is systematically analyzed to investigate the likelihood of future earthquakes occurring near past earthquakes. Three decades of global data (1973-2002) from the National Earthquake Information Center (NEIC) were used for this study Different tectonic environments were analyzed including eight sub-regions of the Earth (all of equal shape and surface area), and smaller, specific tectonic environments, including: Alaska, Australia, Japan and the Interior of the North American Plate. The cellular seismology method was applied to each of the regions. Differences in tectonic environment were investigated to determine their effect on the extent to which past seismicity delineates zones where future large earthquakes are likely to occur. Analysis of the time dependence of these forecasts indicates that the ability to forecast does not decrease over the 30 years of data available. This suggests that the 30 years of NEIC data currently available provides a statistical basis for forecasting locations of future earthquakes, at least on the time scale of the next few decades. Additional monitoring should further elucidate the effect of tectonic environment on the tendency for seismicity to delineate zones where future large earthquakes occur, as well as the time dependency of this phenomenon.
- – 2007-01-01
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The Bush administration, debt forgiveness and development regime change
description- – The Bush administration has taken an unexpected lead in creating policies apparently aimed at decreasing world poverty, pushing the World Bank to convert 45% of its loans to poor countries into grants and the G7 nations to support debt forgiveness for many of the world's poorest countries. These actions, aimed at remolding the international development system, are integral to the Bush administration's foreign policy. They believe their new system of performance-based grants will increase their regulatory grip over developing countries. They are also concerned with sub-Saharan Africa, which they see as a potential hotbed of terrorism, due to its widespread, debt-induced poverty. They believe that the combination of debt forgiveness and grants will contribute to stabilizing this region, while strengthening the legitimacy of both neoliberalism and the"war on terror".
- – 2007-01-01
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Organic crisis and the discursive legitimation of imperial expansion: Examining the continuities of the periods 1872--1900 and 1975--2003
description- – This thesis applies the Gramscian concept of organic crisis to examine the role of domestic problems in the formulation of U.S. foreign policy. By analyzing the social changes that preceded the Spanish American and Second Gulf Wars I argue that both were initiated by a crisis of social identities and a crisis of political legitimacy, or organic crisis. By applying critical discourse analysis this paper elucidates how the organic crises were ultimately overcome and a hegemonic political bloc was reconsolidated through a U.S. exceptionalist discourse. By examining the congruence between these cases I construct a causal model of the preceding socio-economic shifts that laid the foundation for the reunification of collective subjectivities through a discourse of national greatness and expansion; this discourse simultaneously legitimated imperialist policies, and overcome the organic crises.
- – 2007-01-01
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Tyranny and nobility
description- – The relationship between tyranny and nobility is explored through a reading of the opening chapters of Book Seven of Aristotle's Politics and an analysis of Xenophon's presentation of Charmides in the Memorabilia and Symposium . Aristotle embeds his teaching concerning the relation between tyranny and nobility within a discussion of whether the political or philosophic way of life is best. Some fundamental limitations of political life are exposed, as is the way those limitations are expressed in the dynamic between tyranny and nobility. The tension between the political life and the philosophic life is again at issue in Xenophon's presentation of Charmides. Like the political men on whom Aristotle focuses, Charmides is tempted by tyranny, but, unlike the political men, his preference is for the philosophic life. Taken together, the two accounts reveal the full range of the problem.
- – 2007-01-01
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Design and integration of current-mode on-chip interconnect signaling in nanometer technologies
description- – As feature sizes progress into nanometer realms, on-chip interconnects play an increasing role in the overall performance and power consumption of high-performance integrated circuits. Three novel on-chip interconnect communication techniques are presented; (i)Â differential current-transfer sensing, (ii)Â multi-level current signaling, (iii)Â swing-limited interconnect communication; silicon implementation and an integration methodology in conventional CAD flow are proposed. The differential current-transfer sense amplifier ( DCTSA ), is a new static-power mitigated receiver for conventional differential current-sensing. It is compared with the conventional differential current sense amplifier (DCSA ) and standard repeaters. Results in 130nm, 65nm and 45nm show that DCTSA outperforms repeaters for wires with activity of 50% and higher and length longer than 4mm. The multi-level current signaling technique with novel driver and receiver circuits is proposed which encode two bits on one interconnect using current levels. This multi-level system is compared with conventional repeaters for process technologies including 130nm, 90nm, 65nm and 45nm. The impact of process induced parameter variations was analyzed and a process tolerant driver was presented. Compared to repeaters, multi-level current signaling is attractive for wires longer than 4mm and with activity factors more than 40%. A swing-limited interconnect current-mode technique is proposed with a novel low-swing receiver circuit, which achieves energy efficient transmission for on-chip interconnects over repeaters. This swing-limited interconnect system is compared with repeaters in a 65nm industrial CMOS technology. With this signaling technique there is a 56% energy reduction and 21% delay reduction compared to repeaters. Delay savings increase by 8% at supply of 1.4v at iso energy. A total area savings of 86% is obtained in device width with this technique. A methodology and tool for the integration of current-mode interconnect techniques into conventional design flow was presented. The methodology and tool called Network-on-Chip Interconnect Calculator provides results in terms of delay and power for interconnects, and illustrates the effects of delay and power on input parameters in plots. It hides the circuit level details of the proposed current-mode techniques and provides a simple library that can be used by conventional CAD flow. The proposed signaling techniques along with conventional repeater insertion method have been implemented in silicon in IBM 130nm technology through MOSIS for different wirelengths showing proof-of-concept. The test chip is fully functional and the measurement results closely followed the simulated results, thus verifying the validity of the proposed techniques and their benefit over existing techniques for on-chip interconnects.
- – 2006-01-01
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Design validation of behavioral descriptions for arbitrary fault models
description- – The widespread use of hardware/software systems in cost-critical and life-critical applications motivates the need for a system approach to verify functionality. Several obstacles to the verification of hardware/software systems make this a challenging problem. One issue is the high complexity of current systems which derives from both the size and the heterogeneous nature of the designs. The complexity of hardware verification has increased to the point that it dominates the cost of design. Since traditional formal verification techniques are still limited to relatively small portions of a design, researchers have explored simulation-based functional validation to verify functionality by simulating (or emulating) a system description with a given test input sequence. The tractability of validation makes it the only practical solution for many real designs today and in a foreseeable future. The largest component of validation cost is the test generation process required to ensure the detection of design errors. The cost of the test generation process derives from the largely manual nature of the process, making automation of the test generation process essential to greatly reduce design cost and time to market. In order to perform automatic test generation to detect design errors in a behavioral hardware description, this dissertation presents our research on the architecture, application, and analysis of an automatic test generation (ATG) process. In the architecture of ATG, we propose a flexible test generation framework for the design validation of behavioral hardware descriptions in complex hardware/software systems. To achieve the flexibility necessary to target arbitrary fault models, the technique proposed in this dissertation employs a Constraint Logic Programming (CLP) formulation. We formulate the system under test as a CLP problem in order to handle both Boolean and arithmetic constraints. A state-of-art commercial CLP solver is used to solve the ATG constraints to produce test sequence for each fault. Many existing ATG methods are typically limited to the detection of a single fault model. But in practice, no single fault model is considered sufficient to capture the wide range of errors made by designers. In order to ensure detection of a wide range of design error types, our test generation tool can target a range of various arbitrary fault models of systems under test. New fault models can be added by adding CLP constraints to the framework which we build. To test the performance of our ATG process, a set of benchmarks with behavioral VHDL descriptions are chosen. We build a parser to automatically transform the format from VHDL descriptions to the input format recognized by our ATG framework. Validating these benchmarks makes a good start for our ATG framework to handle more, real examples in the future. A significant obstacle to the widespread acceptance of available ATG techniques is the lack of faith in the correlation between fault models and real design errors. Although many validation fault models have been identified in previous research, the capability of these fault models to detect real design errors has never been evaluated. To evaluate the ability of our ATG tool to detect design errors, we have developed a method to analyze behavioral fault models with the detection rate of real defects.
- – 2006-01-01
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A case study of the impact of urban immersion teacher preparation and urban school workplace on the perceived self-efficacy, persistence and institutional commitment of urban school teachers
description- – Urban school teacher preparation and retention have been a major concern of teacher educators, school administrators and policy makers. The purpose of this case study is to explore urban school teachers' understanding of the ways in which their experiences in an urban immersion teacher preparation (UITP) program and in urban school workplace influence their perceived self-efficacy, persistence and institutional commitment as urban school teachers. Literature review is conducted on alternative teacher certification, the Professional Development School movement, the nature of urban school teaching and learning, and the context of teaching theories. A case study approach is employed to investigate the research problem, with the social cognitive theory of self-efficacy used as the conceptual framework for data analysis. The major source of data is semi-structured interviews of UITP program graduates in addition to their personal statements as part of the UITP program application requirement. The case study findings indicate that urban school teacher perceived self-efficacy is a belief that teachers have in their capabilities to meet the task demand of teaching at urban schools with the requisite competence of urban school teachers. The findings suggest that those participants who are staying as urban school teachers have a strong sense of integrated self-efficacy of three dimensions including classroom management, classroom instruction and contextual congruence, and they are motivated to persist and learn new competence despite setbacks and obstacles. The findings suggest that self-efficacy is a necessary but not a sufficient factor influencing the participants' persistence and institutional commitment. Non-efficacy factors, such as salary pay and education managerial bureaucracy, are the most serious barriers to the stayers' persistence in and commitment to teaching at the urban schools. The results have both practice and policy implications for teacher preparation and retention. Given that teachers' self-efficacy beliefs, persistence and institutional commitment interact with school contextual variables, urban school teacher education needs a better defined context sensitive knowledge base of the task demand of teaching and the requisite competence required of urban school teachers; urban school districts need to implement policies addressing teachers' financial concerns and professional development needs to alleviate teacher turnover.
- – 2007-01-01
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Emotional rationality and the fear of death
description- – In this dissertation I discuss emotional rationality generally, and the fear of death specifically. I argue that the intentionality of emotion is one source of difficulty for philosophers who defend the view that the fear of death is irrational. I suggest that since there are several things we can fear when we fear death, the acceptability of some arguments will vary depending on the objects the arguments presuppose. I also argue that philosophers (contemporary and historical) often employed inappropriate conceptions of emotional rationality. If the conceptual framework in which these philosophers were working is unacceptable, then perhaps their arguments are unacceptable as well. I ultimately develop a view of emotional rationality that takes its inspiration from externalist accounts of belief justification. I try to show that, even if the fear of death (as the fear of death's deprivations) is not a"true"emotion, it is nonetheless justified.
- – 2007-01-01
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Unexpected transitions; moving beyond cultural barriers: Successful strategies of female technology education teachers
description- – The purpose of this study is to learn about the ways in which female Technology Education Teachers understand sources of influence on their career choice. The findings from this study are intended to provide key insights in the participants' perspectives that might shed light on how to encourage females to aspire to and enter Technology Education as a profession. The objective of this study is to create a deeper understanding of how some women moved beyond cultural barriers and make"unexpected transitions"to become female technology education teachers. This qualitative study is based on a purposive sampling of ten female technology education teachers.
- – 2007-01-01
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Searching for identity: An exploration of narrative, behavior, material culture, and curriculum as representations of identity in one Armenian day school in the United States
description- – Utilizing the tension inherent in conceptualizations of identity as both a fixed and a transient phenomenon, this dissertation explores perceptions of cultural identity as held by the various members of one Armenian day school in the United States, and by the school itself. In the process, it also considers the emerging question that arises out of its participants' perceptions of the school's own identities. While cultural identity is defined as a sense of belonging to national and ethnic cultures in the context of the nation state, the question of the school and considerations of its identities, on the other hand, raises issues within the context of pedagogy, specifically germane to the complexities of ethnic schooling in the United States. The dissertation's methodology is qualitative. It uses a descriptive cultural studies strategy and an instrumental/intrinsic case study genre to discover aspects of the phenomenon it sets out to study, cultural identity, as well as the context that bounds this phenomenon, the school. The findings reveal as well as imply (a)Â a range of"identity positions"---participants negotiating the boundaries that separate and unite the domains of their Armenianness and Americanness; (b)Â several shifting roles of enculturation and acculturation enacted by the school, which is perceived to mediate between the family and the mainstream of American society; (c)Â an array of multifarious perceptions of the school's identities; (d)Â a preponderance of hyphenated expressions of cultural identity, reflected in the identity positions as well as in samples of the school's literature, characterized by asymmetries of form and content; (e)Â an intricate mix of conceptualizations of the school's curriculum, particularly of its Armenian Studies component; and (f)Â a challenge to the traditionally perceived roles of the ethnic family and the ethnic school as providers, respectively, of"natural"and formal knowledge of ethnicity. This dissertation cautions against apriori interpretations of Armenian-Americanness as a symmetrical construct. It recommends careful consideration of the irregularities inherent in the relationship between this construct's form and content, as signified by the members of the school's community, in order to design a curriculum that is appropriate both pedagogically and culturally.
- – 2007-01-01
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Heterogeneity on the commons: An analysis of use and management of common forests in Himachal Pradesh, India
description- – Community-based natural resource management has become immensely popular among some policy makers on the assumption that involvement of local communities can achieve conservation goals with greater efficiency and equity. However, the community is quite often conceived of as an undifferentiated whole. Given that diverse groups may exist within a community, with heterogeneous interests, abilities, incentives, and social affiliations, such a conception is problematic. This dissertation empirically investigates the effects of heterogeneity on use and management of common forests. This dissertation conducts a meso-level study of heterogeneity using the 'community' as the unit of analysis. The data are derived from fieldwork conducted in the middle Himalayan ranges of Himachal Pradesh, India in 2004. During this fieldwork, survey data were collected in 54 forest communities. This method contrasts with the usual practice of examining individual motivations or conducting a cross-section country-level study. There are two key findings. First, three dimensions of heterogeneity affect collective management of forests: heterogeneity in wealth, social groups and incentives. However, these effects are complex and non-linear. The empirical results suggest that both social and wealth heterogeneity have a non-monotonic relationship with cooperation. In addition, heterogeneity in incentives decreases cooperation conditional on the presence of wealth heterogeneity. These results imply that cooperation does not depend on social parochialism, very high levels of wealth heterogeneity reduce cooperation, and a divergence between wealth and incentive to cooperate decreases the level of collective management. Second, forest use is affected by heterogeneity as well. The sampled communities have access to forests that are common property, in that rights of use are vested with the community and not the individual. This means that all individuals in the community should be able to use the forest to the same degree. However, on investigating the effect of heterogeneity in forest use, the dissertation finds that wealth heterogeneity increases whereas social heterogeneity decreases the extent of forest use even after controlling for market related factors. The results therefore, suggest that the social structure of the community plays an important role in determining both the degree of cooperation and extent of forest use at the community level.
- – 2007-01-01
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Determination and identification of disinfection byproducts from the oxidation of model natural organic compounds
description- – This work includes the investigation and determination of several classes of disinfection by-products from various naturally occurring model compounds using several oxidative and instrumental techniques. Analytical methodology was developed for the determination and identification of nitrosamine species by gas chromatography with time-of-flight mass spectral detection. In addition, this method was successfully evaluated against existing techniques, and applied to real, raw water effluent samples. Identification and determination of various iodinated disinfection byproduct species was accomplished for the further elucidation of potential health risks associated with the municipal disinfected drinking water supply. Finally, products from the oxidation of a model ketoacid (pyruvic acid) by hypochlorous acid were determined to gain a greater understanding of the possible byproducts produced from a treatment facility that utilizes ozonation as primary disinfectant and hypochlorous acid as a secondary oxidizer.
- – 2007-01-01
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Essays on supply chain management
description- – This dissertation addresses three important problems with the shared objective of increasing the efficiency of supply chains. The first one considers a forward distribution network. The other two deal with the reverse flow of product in remanufacturing environments. The dissertation is divided accordingly into three well differentiated parts. The first part considers a multistage inventory system composed of a single warehouse that receives a single product from a single supplier and replenishes the inventory of n retailers through direct shipments in Full-Truckload transportation mode. Based on the structural properties of optimal solutions derived, we develop an exact algorithm that runs in polynomial time for a given number of retailers. To overcome the computational burden when the number of retailers is large, we propose two additional algorithms based on Lagrangian decomposition. Computational experiments show the effectiveness of the algorithms and the gains associated with coordinated versus decentralized systems. The second part of the dissertation considers the joint production, procurement and inventory control problem for an assembly system where one of the two components in the end product is produced through remanufacturing. By acquiring additional information on the quality of returned products, the firm can adopt a more selective recovery process to reduce the uncertainty in the remanufacturing yield. We show that the optimal recovery lot size first increases, then decreases as more information is acquired in a special case and the convexity of the expected total cost in the recovery lot size in a slightly more general model. The third part of the dissertation investigates the profitability of remanufactured products for a monopoly firm in a single period setting. The firm has to decide (1)Â whether to offer both new and remanufactured products or to offer only new products to the market, (2)Â whether to offer some new products as substitutes to remanufactured products. We characterize a threshold for the remanufacturing cost under which offering remanufacturing products is profitable, and a threshold for the production cost of new products which is a necessary condition for the substitution option to be profitable.
- – 2007-01-01
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SensEye: A multi-tier heterogeneous camera sensor network
description- – Rapid technological developments in sensing devices, embedded platforms and wireless communication technologies, have enabled and led to a large research focus in sensor networks. Traditional sensor networks have been designed as networks of homogeneous sensor nodes. Single-tier networks consisting of homogeneous nodes achieve only a subset of application requirements and often sacrifice others. In this thesis, I propose the notion of multi-tier heterogeneous sensor networks, sensors organized hierarchically into multiple tiers. With intelligent use of resources across tiers, multi-tier heterogeneous sensor networks have the potential to simultaneously achieve the conflicting goals of network lifetime, sensing reliability and functionality. I consider a class of sensor networks---camera sensor networks---wireless networks with image sensors. I address the issues of automatic configuration and initialization and design of camera sensor networks. Like any sensor network, initialization of cameras is an important pre-requisite for camera sensor networks applications. Since, camera sensor networks have varying degrees of infrastructure support and resource constraints a single initialization procedure is not appropriate. I have proposed the notions of accurate and approximate initialization to initialize cameras with varying capabilities and resource constraints. I have developed and empirically evaluated Snapshot , an accurate calibration protocol tailored for sensor network deployments. I have also developed approximate initialization techniques that estimate the degree of overlap and region of overlap estimates at each camera. Further, I demonstrate usage of these estimates to instantiate camera sensor network applications. As compared to manual calibration, which can take a long time (order of hours) to calibrate several cameras, is inefficient and error prone, the automated calibration protocol is accurate and greatly reduces the time for accurate calibration---tens of seconds to calibrate a single camera and can easily scale to calibrate several cameras in order of minutes. The approximate techniques demonstrate feasibility of initializing low-power resource constrained cameras with no or limited infrastructure support. With regards to design of camera sensor networks, I present the design and implementation of SensEye , a multi-tier heterogeneous camera sensor network and address the issue of energy-reliability tradeoff. Multi-tier networks provide several levels of reliability and energy usage based on the type of sensor used for application tasks. Using SensEye I demonstrate how multi-tier networks can achieve simultaneous system goals of energy efficiency and reliability.
- – 2007-01-01
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Hierarchical nanostructures and self-assembly of polymers containing metal complex in the side chain
description- – Synthesis of well defined polymers containing metal complexes in the side chain is achieved either by the direct or the indirect approach. The direct approach utilizes NMP and RAFT to copolymerize 2,2':6',2''-terpyridine ligand (terpy) functionalized styrene (Styterpy ) monomer in combination with other comonomers. The indirect approach produced polymers using ATRP technique containing either terpy or [Ru(terpy)2 ]2+ metal complex in the side chain. The indirect approach is considered the best method to obtain terpy or metal complex containing polymers in the side chain. Luminescence block-random copolymers containing [Ir(terpy)2 ]3+ in the side chain were studied. Absorbance and emission spectra compared to a model compound shows that the polymer backbone has a minor effect on the polymer absorbance but produces a larger shift for the phosphorescence signals to higher wavelength. Dynamic light scattering of the [Ir(terpy) 2 ]3+ containing copolymer studied in various solvents showed mono-modal aggregation with decreasing aggregate size as the solvent dielectric increased. The copolymer precursor P(S-b-ACterpy ) shows multi-modal aggregation in different solvents with the majority population consistent with single chains. This difference in behavior between the two polymers is attributed to the electrolytic nature of the complex and the amphiphilicity induced by the metal complex. Homopolymers containing [Ru(terpy)2 ]+2 in the side chain are prepared in which the complex contained either a long hydrophobic C16 -alkyl group or only hydrogen at the 4'-terpy position. The homopolymers containing the C16 -alkyl groups showed lyotropic liquid crystalline (LC) behavior in chloroform solutions from room temperature to 60°C and self assembled in the bulk to form hexagonal arrays of cylinders. In addition, this alkyl side chain was observed to crystallize in the solid state. Homopolymers without the C16 -alkyl group showed no lyotropic LC nor any crystallization behavior. Diblock and tetra-arm star copolymers containing [Ru(terpy)2 ] +2 with C16 -alkyl group in the side chain were studied in which the diblock show lyotropic LC properties and microphase separate in the bulk into hierarchical cylinder-within-lamella morphology. The star polymer show birefringence and microphase separate in the bulk. Both copolymers have crystalline properties due to the C16 -alkylgroup. The material design emphasizes the relationship between the molecular structure and self-organization of these polymers.
- – 2007-01-01
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