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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A model-based approach to System of Systems risk management

Kinder, Andrew M. K. January 2017 (has links)
The failure of many System of Systems (SoS) enterprises can be attributed to the inappropriate application of traditional Systems Engineering (SE) processes within the SoS domain, because of the mistaken belief that a SoS can be regarded as a single large, or complex, system. SoS Engineering (SoSE) is a sub-discipline of SE; Risk Management and Modelling and Simulation (M&S) are key areas within SoSE, both of which also lie within the traditional SE domain. Risk Management of SoS requires a different approach to that currently taken for individual systems; if risk is managed for each component system then it cannot be assumed that the aggregated affect will be to mitigate risk at the SoS level. A literature review was undertaken examining three themes: (1) SoS Engineering (SoSE), (2) M&S and (3) Risk. Theme 1 of the literature provided insight into the activities comprising SoSE and its difference from traditional SE with risk management identified as a key activity. The second theme discussed the application of M&S to SoS, providing an output, which supported the identification of appropriate techniques and concluding that, the inherent complexity of a SoS required the use of M&S in order to support SoSE activities. Current risk management approaches were reviewed in theme 3 as well as the management of SoS risk. Although some specific examples of the management of SoS risk were found, no mature, general approach was identified, indicating a gap in current knowledge. However, it was noted most of these examples were underpinned by M&S approaches. It was therefore concluded a general approach SoS risk management utilising M&S methods would be of benefit. In order to fill the gap identified in current knowledge, this research proposed a new model based approach to Risk Management where risk identification was supported by a framework, which combined SoS system of interest dimensions with holistic risk types, where the resulting risks and contributing factors are captured in a causal network. Analysis of the causal network using a model technique selection tool, developed as part of this research, allowed the causal network to be simplified through the replacement of groups of elements within the network by appropriate supporting models. The Bayesian Belief Network (BBN) was identified as a suitable method to represent SoS risk. Supporting models run in Monte Carlo Simulations allowed data to be generated from which the risk BBNs could learn, thereby providing a more quantitative approach to SoS risk management. A method was developed which provided context to the BBN risk output through comparison with worst and best-case risk probabilities. The model based approach to Risk Management was applied to two very different case studies: Close Air Support mission planning and the Wheat Supply Chain, UK National Food Security risks, demonstrating its effectiveness and adaptability. The research established that the SoS SoI is essential for effective SoS risk identification and analysis of risk transfer, effective SoS modelling requires a range of techniques where suitability is determined by the problem context, the responsibility for SoS Risk Management is related to the overall SoS classification and the model based approach to SoS risk management was effective for both application case studies.
12

A model for inventive ideation in physico-mechanical systems

Ross, Victor Emul 21 July 2008 (has links)
Please read the abstract in the section 00front of this document / Thesis (PhD (Technology Management))--University of Pretoria, 2008. / Graduate School of Technology Management (GSTM) / unrestricted
13

A systems engineering approach to the design of a COTS management system

Basil, Daniel L. 16 December 2009 (has links)
This project applies the management systems engineering methodology to the design and development of a management tool to be used in managing change of the Commercial-Off-The-Shelf [COTS] software, firmware, and hardware utilized within the Mapping Branch of the National Imagery and Mapping Agency [NIMA] (formerly known as the Defense Mapping Agency [DMA J). The management tool is used to support the management process overlaying the work process for changing COTS products. By using the management systems engineering methodology to understand how COTS products are changed, the functional requirements for a management tool can be derived in a clear and concise manner. Concurrently, the systems approach is applied in the development of the management tool, referred to as the COTS Management System. The COTS Management System is identified as required by NIMA due to the increasing number of COTS products being used within the Digital Production System [DPS]. The DPS is NIMA's conglomeration of segmented computer systems combined to provide the tools and functionality necessary to produce the myriad of mapping, charting, and geodesic products in both hard-copy and digital format. NIMA also desires to implement the COTS Management System in an effort to achieve the Software Engineering Institutes [SEI] Capability Maturity Model [CMM] Level 3. / Master of Science
14

Nurse Faculty Job Satisfaction: A National Survey

Moody, Nancy B. 01 January 1996 (has links)
Faculty dissatisfaction and fewer qualified recruits choosing a career in academia threaten the integrity of the higher education system. Retention of highly qualified nurse faculty affects the reputation of the school of nursing, the faculty commitment to the organization, and the learning environment for students. Through use of a system's framework derived from Neuman and Kast and Rosenzweig, the purpose of this survey was to ascertain the relationship between job satisfaction among nurse faculty and selected demographic variables, organizational characteristics, and role orientation. Approximately 80 per cent of the schools of nursing in the target population of universities offering a doctorate in nursing participated in the study. The overall subject response rate was 60 per cent. Instruments used for data collection included three researcher-developed tools and two standardized instruments to measure job satisfaction (the Job Descriptive Index and the Job in General Scale). Significant correlations (P < .05) emerged between each of the demographic variables and at least one of the criterion measures of job satisfaction. In addition to descriptive statistics and correlation analysis, a stepwise linear regression-correlation analysis showed that salary, degree level of nursing students taught, and length of annual contract were significant indicators of nurse faculty job satisfaction.
15

Energy-Efficient Distributed Relay and Power Control in Cognitive Radio Cooperative Communications

Luo, C., Min, Geyong, Yu, F.R., Chen, M., Yang, L.T., Leung, V.C.M. January 2013 (has links)
no / In cognitive radio cooperative communication (CR-CC) systems, the achievable data rate can be improved by increasing the transmission power. However, the increase in power consumption may cause the interference with primary users and reduce the network lifetime. Most previous work on CR-CC did not take into account the tradeoff between the achievable data rate and network lifetime. To fill this gap, this paper proposes an energy-efficient joint relay selection and power allocation scheme in which the state of a relay is characterized by the channel condition of all related links and its residual energy. The CR-CC system is formulated as a multi-armed restless bandit problem where the optimal policy is decided in a distributed way. The solution to the restless bandit formulation is obtained through a first-order relaxation method and a primal-dual priority-index heuristic, which can reduce dramatically the on-line computation and implementation complexity. According to the obtained index, each relay can determine whether to provide relaying or not and also can control the corresponding transmission power. Extensive simulation experiments are conducted to investigate the effectiveness of the proposed scheme. The results demonstrate that the power consumption is reduced significantly and the network lifetime is increased more than 40%.
16

Visualization of Knowledge Spaces to Enable Concurrent, Embedded and Transformative Input to Knowledge Building Processes

Teplovs, Christopher 01 September 2010 (has links)
This thesis focuses on the creation of a systems architecture to help inform development of next generation knowledge-building environments. The architectural model consists of three components: an infrastructure layer, a discourse layer, and a visualization layer. The Knowledge Space Visualizer (KSV), which defines the top visualization layer, is a prototypic system for showing reconstructed representations of discourse-based artifacts and facilitating assessment in light of patterns of interactivity of participants and their ideas. The KSV uses Latent Semantic Analysis to extend techniques from Social Network Analysis, making it possible to infer relationships among note contents. Thus idea networks can be studied in conjunction with social networks in online discourse. Further, benchmark corpora can be used to determine knowledge advances, and systems of interactivity leading to them. Results can then provide feedback to students and teachers to support them in obtaining continually higher level achievements. In addition to visual representations, the KSV provides quantitative network metrics such as degree and density. Data drawn from 9- and 10-year-old students working on a six-week unit on optics were used to illustrate some of the functionality of the KSV. Three studies show ways in which new visualizations can be used: (a) to highlight relationships among notes, (b) as a way of tracking the development of discourse over time, and (c) as an assessment tool. Implications for the design of knowledge building environments, assessment tools, and design-based research are discussed.
17

Visualization of Knowledge Spaces to Enable Concurrent, Embedded and Transformative Input to Knowledge Building Processes

Teplovs, Christopher 01 September 2010 (has links)
This thesis focuses on the creation of a systems architecture to help inform development of next generation knowledge-building environments. The architectural model consists of three components: an infrastructure layer, a discourse layer, and a visualization layer. The Knowledge Space Visualizer (KSV), which defines the top visualization layer, is a prototypic system for showing reconstructed representations of discourse-based artifacts and facilitating assessment in light of patterns of interactivity of participants and their ideas. The KSV uses Latent Semantic Analysis to extend techniques from Social Network Analysis, making it possible to infer relationships among note contents. Thus idea networks can be studied in conjunction with social networks in online discourse. Further, benchmark corpora can be used to determine knowledge advances, and systems of interactivity leading to them. Results can then provide feedback to students and teachers to support them in obtaining continually higher level achievements. In addition to visual representations, the KSV provides quantitative network metrics such as degree and density. Data drawn from 9- and 10-year-old students working on a six-week unit on optics were used to illustrate some of the functionality of the KSV. Three studies show ways in which new visualizations can be used: (a) to highlight relationships among notes, (b) as a way of tracking the development of discourse over time, and (c) as an assessment tool. Implications for the design of knowledge building environments, assessment tools, and design-based research are discussed.
18

Designing a knowledge management architecture to support self-organization in a hotel chain

Kaldis, Emmanuel January 2014 (has links)
Models are incredibly insidious; they slide undetected into discussions and then dominate the way people think. Since Information Systems (ISs) and particularly Knowledge Management Systems (KMSs) are socio-technical systems, they unconsciously embrace the characteristics of the dominant models of management thinking. Thus, their limitations can often be attributed to the deficiencies of the organizational models they aim to support. Through the case study of a hotel chain, this research suggests that contemporary KMSs in the hospitality sector are still grounded in the assumptions of the mechanistic organizational model which conceives an organization as a rigid hierarchical entity governed from the top. Despite the recent technological advances in terms of supporting dialogue and participation between members, organizational knowledge is still transferred vertically; from the top to the bottom or from the bottom to the top. A number of limitations still exist in terms of supporting effectively the transfer of knowledge horizontally between the geographically distributed units of an organization. Inspired from the key concepts of the more recent complex systems model, referred frequently as complexity theories, a Knowledge Management Architecture (KMA) is proposed aiming to re-conceptualize the existing KMSs towards conceiving an organization as a set self-organizing communities of practice (CoP). In every such CoP, order is created from the dynamic exchange of knowledge between the structurally similar community members. Thus, the focus of the KMA is placed on capturing systematically for reuse the architectural knowledge created upon every initiative for change and share such knowledge with the rest of the members of the CoP. A KMS was also developed to support the dynamic dimensions that the KMA proposes. The KMS was then applied in the case of the hotel chain, where it brought significant benefits which constitute evidence of an improved self-organizing ability. The previously isolated hotel units residing in distant regions could now trace but also reapply easily changes undertaken by the other community members. Top-management’s intervention to promote change was reduced, while the pace of change increased. Moreover, the organizational cohesion, the integration of new members as well as the level of management alertness was enhanced. The case of the hotel chain is indicative. It is believed that the KMA proposed can be applicable to geographically distributed organizations operating in different sectors too. At the same time, this research contributes to the recent discourse between the fields of IS and complexity by demonstrating how fundamental concepts from complexity such as self-organization, emergence and edge-of-chaos can be embraced by contemporary KMSs.
19

Oskarshamn - A Smart Energy Island Assessment

Ramaswamy, Vivek January 2015 (has links)
Mitigating climate change lies to a large part within the Energy System. In order to make it sustainable and efficient, policies have to be framed accordingly. This study focuses on formulation of policies based on future projections of the energy demand in Oskarshamn municipality of Sweden. Oskarshamn is a former industrial municipality, whose economic activity is in decline and it requires policies that accelerates its growth. It is also stereo-typical of much of Europe, as industrial activities are transferred elsewhere and regions are left to re-invent themselves. Questions such as “how to make the existing system more efficient” and “what is the best energy saving alternative”, have to be answered. For which, Long range Energy Alternatives Planning (LEAP) tool is used to create scenarios based on different pathways and to project the energy demand in the future. The business as usual scenario is compared with mitigation scenario considering various energy efficiency measures. The measures mainly focus on Demand Side Management and improving energy lifestyle interactions. Examples include the impact of electric vehicles (EV) in the transport sector and effects of better insulation in residential buildings, etc. Nuclear is currently the main source and would possibly be phased out in the horizon and thus creating a need for alternative and sustainable sources of energy. The renewable energy scenario focuses on proposals for mixing renewable fuels in the energy supply side. These are not without costs and opportunities which are discussed in the study. The outcomes work a clear delineation of Greenhouse gas mitigation options, which in collaboration with the municipality would form the basis for a policy action plan.
20

Model-driven development of information systems

Wang, Chen-Wei January 2012 (has links)
The research presented in this thesis is aimed at developing reliable information systems through the application of model-driven and formal techniques. These are techniques in which a precise, formal model of system behaviour is exploited as source code. As such a model may be more abstract, and more concise, than source code written in a conventional programming language, it should be easier and more economical to create, to analyse, and to change. The quality of the model of the system can be ensured through certain kinds of formal analysis and fixed accordingly if necessary. Most valuably, the model serves as the basis for the automated generation or configuration of a working system. This thesis provides four research contributions. The first involves the analysis of a proposed modelling language targeted at the model-driven development of information systems. Logical properties of the language are derived, as are properties of its compiled form---a guarded substitution notation. The second involves the extension of this language, and its semantics, to permit the description of workflows on information systems. Workflows described in this way may be analysed to determine, in advance of execution, the extent to which their concurrent execution may introduce the possibility of deadlock or blocking: a condition that, in this context, is synonymous with a failure to achieve the specified outcome. The third contribution concerns the validation of models written in this language by adapting existing techniques of software testing to the analysis of design models. A methodology is presented for checking model consistency, on the basis of a generated test suite, against the intended requirements. The fourth and final contribution is the presentation of an implementation strategy for the language, targeted at standard, relational databases, and an argument for its correctness, based on a simple, set-theoretic semantics for structure and operations.

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