842 resultados para Technologies of power


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In this dissertation, the National Survey of Student Engagement (NSSE) serves as a nodal point through which to examine the power relations shaping the direction and practices of higher education in the twenty-first century. Theoretically, my analysis is informed by Foucault’s concept of governmentality, briefly defined as a technology of power that influences or shapes behavior from a distance. This form of governance operates through apparatuses of security, which include higher education. Foucault identified three essential characteristics of an apparatus—the market, the milieu, and the processes of normalization—through which administrative mechanisms and practices operate and govern populations. In this project, my primary focus is on the governance of faculty and administrators, as a population, at residential colleges and universities. I argue that the existing milieu of accountability is one dominated by the neoliberal assumption that all activity—including higher education—works best when governed by market forces alone, reducing higher education to a market-mediated private good. Under these conditions, what many in the academy believe is an essential purpose of higher education—to educate students broadly, to contribute knowledge for the public good, and to serve as society’s critic and social conscience (Washburn 227)—is being eroded. Although NSSE emerged as a form of resistance to commercial college rankings, it did not challenge the forces that empowered the rankings in the first place. Indeed, NSSE data are now being used to make institutions even more responsive to market forces. Furthermore, NSSE’s use has a normalizing effect that tends to homogenize classroom practices and erode the autonomy of faculty in the educational process. It also positions students as part of the system of surveillance. In the end, if aspects of higher education that are essential to maintaining a civil society are left to be defined solely in market terms, the result may be a less vibrant and, ultimately, a less just society.

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It is an important and difficult challenge to protect modern interconnected power system from blackouts. Applying advanced power system protection techniques and increasing power system stability are ways to improve the reliability and security of power systems. Phasor-domain software packages such as Power System Simulator for Engineers (PSS/E) can be used to study large power systems but cannot be used for transient analysis. In order to observe both power system stability and transient behavior of the system during disturbances, modeling has to be done in the time-domain. This work focuses on modeling of power systems and various control systems in the Alternative Transients Program (ATP). ATP is a time-domain power system modeling software in which all the power system components can be modeled in detail. Models are implemented with attention to component representation and parameters. The synchronous machine model includes the saturation characteristics and control interface. Transient Analysis Control System is used to model the excitation control system, power system stabilizer and the turbine governor system of the synchronous machine. Several base cases of a single machine system are modeled and benchmarked against PSS/E. A two area system is modeled and inter-area and intra-area oscillations are observed. The two area system is reduced to a two machine system using reduced dynamic equivalencing. The original and the reduced systems are benchmarked against PSS/E. This work also includes the simulation of single-pole tripping using one of the base case models. Advantages of single-pole tripping and comparison of system behavior against three-pole tripping are studied. Results indicate that the built-in control system models in PSS/E can be effectively reproduced in ATP. The benchmarked models correctly simulate the power system dynamics. The successful implementation of a dynamically reduced system in ATP shows promise for studying a small sub-system of a large system without losing the dynamic behaviors. Other aspects such as relaying can be investigated using the benchmarked models. It is expected that this work will provide guidance in modeling different control systems for the synchronous machine and in representing dynamic equivalents of large power systems.

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In the current market system, power systems are operated at higher loads for economic reasons. Power system stability becomes a genuine concern in such operating conditions. In case of failure of any larger component, the system may become stressed. These events may start cascading failures, which may lead to blackouts. One of the main reasons of the major recorded blackout events has been the unavailability of system-wide information. Synchrophasor technology has the capability to provide system-wide real time information. Phasor Measurement Units (PMUs) are the basic building block of this technology, which provide the Global Positioning System (GPS) time-stamped voltage and current phasor values along with the frequency. It is being assumed that synchrophasor data of all the buses is available and thus the whole system is fully observable. This information can be used to initiate islanding or system separation to avoid blackouts. A system separation strategy using synchrophasor data has been developed to answer the three main aspects of system separation: (1) When to separate: One class support machines (OC-SVM) is primarily used for the anomaly detection. Here OC-SVM was used to detect wide area instability. OC-SVM has been tested on different stable and unstable cases and it is found that OC-SVM has the capability to detect the wide area instability and thus is capable to answer the question of “when the system should be separated”. (2) Where to separate: The agglomerative clustering technique was used to find the groups of coherent buses. The lines connecting different groups of coherent buses form the separation surface. The rate of change of the bus voltage phase angles has been used as the input to this technique. This technique has the potential to exactly identify the lines to be tripped for the system separation. (3) What to do after separation: Load shedding was performed approximately equal to the sum of power flows along the candidate system separation lines should be initiated before tripping these lines. Therefore it is recommended that load shedding should be initiated before tripping the lines for system separation.

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With the development and capabilities of the Smart Home system, people today are entering an era in which household appliances are no longer just controlled by people, but also operated by a Smart System. This results in a more efficient, convenient, comfortable, and environmentally friendly living environment. A critical part of the Smart Home system is Home Automation, which means that there is a Micro-Controller Unit (MCU) to control all the household appliances and schedule their operating times. This reduces electricity bills by shifting amounts of power consumption from the on-peak hour consumption to the off-peak hour consumption, in terms of different “hour price”. In this paper, we propose an algorithm for scheduling multi-user power consumption and implement it on an FPGA board, using it as the MCU. This algorithm for discrete power level tasks scheduling is based on dynamic programming, which could find a scheduling solution close to the optimal one. We chose FPGA as our system’s controller because FPGA has low complexity, parallel processing capability, a large amount of I/O interface for further development and is programmable on both software and hardware. In conclusion, it costs little time running on FPGA board and the solution obtained is good enough for the consumers.

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Graphene, which is a two-dimensional carbon material, exhibits unique properties that promise its potential applications in photovoltaic devices. Dye-sensitized solar cell (DSSC) is a representative of the third generation photovoltaic devices. Therefore, it is important to synthesize graphene with special structures, which possess excellent properties for dye-sensitized solar cells. This dissertation research was focused on (1) the effect of oxygen content on the structure of graphite oxide, (2) the stability of graphene oxide solution, (3) the application of graphene precipitate from graphene oxide solution as counter electrode for DSSCs, (4) the development of a novel synthesis method for the three-dimensional graphene with honeycomb-like structure, and (5) the exploration of honeycomb structured graphene (HSG) as counter electrodes for DSSCs. Graphite oxide is a crucial precursor to synthesize graphene sheets via chemical exfoliation method. The relationship between the oxygen content and the structures of graphite oxides was still not explored. In this research, the oxygen content of graphite oxide is tuned by changing the oxidation time and the effect of oxygen content on the structure of graphite oxide was evaluated. It has been found that the saturated ratio of oxygen to carbon is 0.47. The types of functional groups in graphite oxides, which are epoxy, hydroxyl, and carboxylgroups, are independent of oxygen content. However, the interplanar space and BET surface area of graphite oxide linearly increases with increasing O/C ratio. Graphene oxide (GO) can easily dissolve in water to form a stable homogeneous solution, which can be used to fabricate graphene films and graphene based composites. This work is the first research to evaluate the stability of graphene oxide solution. It has been found that the introduction of strong electrolytes (HCl, LiOH, LiCl) into GO solution can cause GO precipitation. This indicates that the electrostatic repulsion plays a critical role in stabilizing aqueous GO solution. Furthermore, the HCl-induced GO precipitation is a feasible approach to deposit GO sheets on a substrate as a Pt-free counter electrode for a dye-sensitized solar cell (DSSC), which exhibited 1.65% of power conversion efficiency. To explore broad and practical applications, large-scale synthesis with controllable integration of individual graphene sheets is essential. A novel strategy for the synthesis of graphene sheets with three-dimensional (3D) Honeycomb-like structure has been invented in this project based on a simple and novel chemical reaction (Li2O and CO to graphene and Li2CO3). The simultaneous formation of Li2CO3 with graphene not only can isolate graphene sheets from each other to prevent graphite formation during the process, but also determine the locally curved shape of graphene sheets. After removing Li2CO3, 3D graphene sheets with a honeycomb-like structure were obtained. This would be the first approach to synthesize 3D graphene sheets with a controllable shape. Furthermore, it has been demonstrated that the 3D Honeycomb-Structured Graphene (HSG) possesses excellent electrical conductivity and high catalytic activity. As a result, DSSCs with HSG counter electrodes exhibit energy conversion efficiency as high as 7.8%, which is comparable to that of an expensive noble Pt electrode.

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Principal Component Analysis (PCA) is a popular method for dimension reduction that can be used in many fields including data compression, image processing, exploratory data analysis, etc. However, traditional PCA method has several drawbacks, since the traditional PCA method is not efficient for dealing with high dimensional data and cannot be effectively applied to compute accurate enough principal components when handling relatively large portion of missing data. In this report, we propose to use EM-PCA method for dimension reduction of power system measurement with missing data, and provide a comparative study of traditional PCA and EM-PCA methods. Our extensive experimental results show that EM-PCA method is more effective and more accurate for dimension reduction of power system measurement data than traditional PCA method when dealing with large portion of missing data set.

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In recent years, advanced metering infrastructure (AMI) has been the main research focus due to the traditional power grid has been restricted to meet development requirements. There has been an ongoing effort to increase the number of AMI devices that provide real-time data readings to improve system observability. Deployed AMI across distribution secondary networks provides load and consumption information for individual households which can improve grid management. Significant upgrade costs associated with retrofitting existing meters with network-capable sensing can be made more economical by using image processing methods to extract usage information from images of the existing meters. This thesis presents a new solution that uses online data exchange of power consumption information to a cloud server without modifying the existing electromechanical analog meters. In this framework, application of a systematic approach to extract energy data from images replaces the manual reading process. One case study illustrates the digital imaging approach is compared to the averages determined by visual readings over a one-month period.

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Post-Fordist economies come along with post-welfarist societies marked by intensified cultural individualism and increased structural inequalities. These conditions are commonly held to be conducive to relative deprivation and, thereby, anomic crime. At the same time, post-welfarist societies develop a new ‘balance of power’ between institutions providing for welfare regulation, such as the family, the state and the (labour) market – and also the penal system. These institutions are generally expected to improve social integration, ensure conformity and thus reduce anomic crime. Combining both perspectives, we analyse the effects of moral individualism, social inequality, and different integration strategies on crime rates in contemporary societies through the lenses of anomie theory. To test our hypotheses, we draw on time-series cross-section data compiled from different data sources (OECD, UN, WHO, WDI) for twenty developed countries in the period 1970-2004, and run multiple regressions that control for country-specific effects. Although we find some evidence that the mismatch between cultural ideal (individual inclusion) and structural reality (stratified exclusion) increases the anomic pressure, whereas conservative (i. e. family-based), social-democratic (i. e. state-based) and liberal (i. e. market-based) integration strategies to a certain extent prove effective in controlling the incidence of crime, the results are not very robust. Moreover, reservations have to be made regarding the effects of “market” income inequality as well as familialist, unionist and liberalist employment policies that are shown to have reversed effects in our sample: the former reducing, the latter occasionally increasing anomic crime. As expected, the mismatch between cultural ideal (individual inclusion) and structural reality (stratified exclusion) increases the anomic pressure, whereas conservative (i. e. family-based), social-democratic (i. e. state-based) and liberal (i. e. market-based) integration strategies generally prove effective in controlling the incidence of crime. Nevertheless, we conclude that the new cult of the individual undermines the effectiveness of conservative and social-democratic integration strategies and drives societies towards more “liberal” regimes that build on incentive as well as punitive elements.

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Militias and vigilantes that assume public authority by fighting crime reject the laws of the state, yet they have no other set of rules to regulate their activities. Many of them claim to be accountable to their ethnic or religious community on whose behalf they operate. But their communities have found no means to institutionalise control over them. Moreover, there are no institutions to settle conflicts between different militias and vigilantes. On a local level, rival groups have reached informal arrangements. However, these compromises are unstable, as they reflect fragile alliances and shifting balances of power. Leaders of militias and other 'self-determination groups' have suggested organising a conference of all ethnic nationalities in Nigeria in order to design a new constitution that would give militias and vigilantes a legal role and define their authority. But the groups compared in this article – Oodua People's Congress, Sharia Vigilantes, Bakassi Boys, MASSOB, and Niger Delta militias – pursue very divergent interests, and they are far from reaching a consensus on how to contain violence between them.

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Among the many thousand scarabs, scaraboids and other stamp-seal amulets unearthed in Iron Age contexts in Cis- and Transjordan, there are many such seals showing royal Egyptian imagery on their bases. Focusing mainly on Pharaonic motifs, the paper aims to catalogue the principal iconemes, to trace their development throughout the Iron Ages and to extrapolate their significance vis-à-vis the contemporary glyptic assemblages. As will be shown, the royal imagery of the Egyptian king underwent considerable changes during pre-monarchic and monarchic times in Israel/Judah. This allows – to some extent – deducing the perception of the ‘image’ of the Egyptian king in this part of the Southern Levant at the close of the second and during the first centuries of the first millennium BCE. While the local seal production not only vividly copied earlier and contemporary Egyptian prototypes, it also developed idiosyncratic ‘Pharaonic’ motifs that were produced for the local market. On the other hand, imported Egyptian glyptic goods – such as scarabs and other amulet types – reveal further facets of the consumer behavior. They, too, shed light upon the ideological and religious preferences of the local population and illuminate the development of the vernacular attitude towards the Pharaonic symbols of power – including their obvious political and sacred connotations.

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Individual Video Training iVT and Annotating Academic Videos AAV: two complementing technologies 1. Recording communication skills training sessions and reviewing them by oneself, with peers, and with tutors has become standard in medical education. Increasing numbers of students paired with restrictions of financial and human resources create a big obstacle to this important teaching method. 2. Everybody who wants to increase efficiency and effectiveness of communication training can get new ideas from our technical solution. 3. Our goal was to increase the effectiveness of communication skills training by supporting self, peer and tutor assessment over the Internet. Two technologies of SWITCH, the national foundation to support IT solutions for Swiss universities, came handy for our project. The first is the authentication and authorization infrastructure providing all Swiss students with a nationwide single login. The second is SWITCHcast which allows automated recording, upload and publication of videos in the Internet. Students start the recording system by entering their single login. This automatically links the video with their password. Within a few hours, they find their video password protected on the Internet. They now can give access to peers and tutors. Additionally, an annotation interface was developed. This software has free text as well as checklist annotations capabilities. Tutors as well as students can create checklists. Tutor’s checklists are not editable by students. Annotations are linked to tracks. Tracks can be private or public. Public means visible to all who have access to the video. Annotation data can be exported for statistical evaluation. 4. The system was well received by students and tutors. Big numbers of videos were processed simultaneously without any problems. 5. iVT http://www.switch.ch/aaa/projects/detail/UNIBE.7 AAV http://www.switch.ch/aaa/projects/detail/ETHZ.9

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The sustainability of regional development can be usefully explored through several different lenses. In situations in which uncertainties and change are key features of the ecological landscape and social organization, critical factors for sustainability are resilience, the capacity to cope and adapt, and the conservation of sources of innovation and renewal. However, interventions in social-ecological systems with the aim of altering resilience immediately confront issues of governance. Who decides what should be made resilient to what? For whom is resilience to be managed, and for what purpose? In this paper we draw on the insights from a diverse set of case studies from around the world in which members of the Resilience Alliance have observed or engaged with sustainability problems at regional scales. Our central question is: How do certain attributes of governance function in society to enhance the capacity to manage resilience? Three specific propositions were explored: ( 1) participation builds trust, and deliberation leads to the shared understanding needed to mobilize and self-organize; ( 2) polycentric and multilayered institutions improve the fit between knowledge, action, and social-ecological contexts in ways that allow societies to respond more adaptively at appropriate levels; and ( 3) accountable authorities that also pursue just distributions of benefits and involuntary risks enhance the adaptive capacity of vulnerable groups and society as a whole. Some support was found for parts of all three propositions. In exploring the sustainability of regional social-ecological systems, we are usually faced with a set of ecosystem goods and services that interact with a collection of users with different technologies, interests, and levels of power. In this situation in our roles as analysts, facilitators, change agents, or stakeholders, we not only need to ask: The resilience of what, to what? We must also ask: For whom?