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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.
91

Surface-normal multiple quantum well electroabsorption modulators based on GaAs-related materials

Junique, Stéphane January 2005 (has links)
No description available.
92

Living and learning together : integrating developmental systems theory, radical embodied cognitive science, and relational thinking in the study of social learning

Pagnotta, Murillo January 2018 (has links)
Behavioural scientists argue that ‘social learning' provides the link between biological phenomena and cultural phenomena because of its role in the ‘cultural transmission' of knowledge among individuals within and across generations. However, leading authors within the social sciences have proposed alternative ways of thinking about social life not founded on the Modern oppositions including nature-culture, biology-culture, body-mind, and individual-society. Similarly, the distinction between a domain of nature and a domain of nurture has also been extensively criticized within biology. Finally, advocates of ‘radical embodied cognitive science' offer an alternative to the representational-computational view of the mind which supports the conventional notion of culture and cultural information. This thesis attempts to integrate developmental systems theory, radical embodied cognitive science, and relational thinking, with the goal to bring the field of social learning closer to these critical theoretical developments. In Chapter 2, I find no justification for the claim that the genome carries information in the sense of specification of biological form. Chapter 3 presents a view of ontogeny as a historical, relational, constructive and contingent process. Chapter 4 uses the notions of environmental information, abilities, affordances, and intentions to make sense of behaviour and learning. In Chapter 5, I argue that the notion of social learning can be understood in terms of relational histories of development rather than in terms of transmission of information. I then report empirical studies investigating behavioural coordination and social learning consistent with this theoretical framework. Chapter 6 presents evidence that dyads in a joint making activity synchronize their attention constrained by their changing situation and that coordination of attention is predictive of implicit and explicit learning. Chapter 7 presents evidence that joint attention does not require gaze following and that attentional coordination is predictive of learning a manual task. Together, these theoretical and empirical studies suggest a new way of thinking about how humans and other animals live and learn socially, one that is consistent with critical theoretical and philosophical developments that are currently neglected in the literature on social learning.
93

A Model for Multiperiod Route Planning and a Tabu Search Method for Daily Log Truck Scheduling

Holm, Christer, Larsson, Andreas January 2004 (has links)
<p>The transportation cost of logs from forest to customers is a large part of the overall cost for the Swedish forestry industry. Finding good routes from harvesting points to saw and pulp mills is a complex task, where the total number of feasible routes is extremely high. In this thesis we present two methods for log truck scheduling. </p><p>The first is to, from a given set of routes, find the most valuable subset that fulfils the customers demand. We use a model that is similar to the set partitioning problem and a method that is referred to as a composite pricing coupled with Branch and Bound. The composite pricing based method prices the routes (columns) and chooses the most valuable ones that are then added to the LP relaxation. Once an LP optimum is found, the Branch and Bound method is used to find an integer optimum solution. We have tested this on a case of realistic size. </p><p>The second method is a tabu search heuristic. Here, the purpose is to create efficient and qualitative routes from a given number of trips (referred to as predefined trips). From a start solution tabu search systematically generates new solutions. This method was tested on a small problem and on a five times larger problem to study how the size of the problem affected the result. It was also tested and compared on two cases in which the backhauling possibilities (i.e. instead of traveling empty the truck picks up another load on the return trip) had and had not been studied. The composite pricing based method and the tabu search method proved to be very useful for this kind of scheduling.</p>
94

Efficient Updating Shortest Path Calculations for Traffic Assignment

Holmgren, Johan January 2004 (has links)
<p>Traffic planning in a modern congested society is an important and time consuming procedure. Finding fast algorithms for solving traffic problems is therefore of great interest for traffic planners allover the world. </p><p>This thesis concerns solving the fixed demand traffic assignment problem (TAP) on a number of different transportation test networks. TAP is solved using the Frank-Wolfe algorithm and the shortest path problems that arise as subproblems to the Frank-Wolfe algorithm are solved using the network simplex algorithm. We evaluate how a number of existing pricing strategies to the network simplex algorithm performs with TAP. We also construct a new efficient pricing strategy, the Bucket Pricing Strategy, inspired by the heap implementation of Dijkstra's method for shortest path problems. This pricing strategy is, together with the actual use of the network simplex algorithm, the main result of the thesis and the pricing strategy is designed to take advantage of the special structure of TAP. In addition to performing tests on the conventional Frank-Wolfe algorithm, we also test how the different pricing strategies perform on Frank-Wolfe algorithms using conjugate and bi-conjugate search directions. </p><p>These test results show that the updating shortest path calculations obtained by using the network simplex outperforms the non-updating Frank-Wolfe algorithms. Comparisons with Bar-Gera's OBA show that our implementation, especially together with the bucket pricing strategy, also outperforms this algorithm for relative gaps down to 10E-6.</p>
95

A convex optimization approach to complexity constrained analytic interpolation with applications to ARMA estimation and robust control

Blomqvist, Anders January 2005 (has links)
Analytical interpolation theory has several applications in systems and control. In particular, solutions of low degree, or more generally of low complexity, are of special interest since they allow for synthesis of simpler systems. The study of degree constrained analytic interpolation was initialized in the early 80's and during the past decade it has had significant progress. This thesis contributes in three different aspects to complexity constrained analytic interpolation: theory, numerical algorithms, and design paradigms. The contributions are closely related; shortcomings of previous design paradigms motivate development of the theory, which in turn calls for new robust and efficient numerical algorithms. Mainly two theoretical developments are studied in the thesis. Firstly, the spectral Kullback-Leibler approximation formulation is merged with simultaneous cepstral and covariance interpolation. For this formulation, both uniqueness of the solution, as well as smoothness with respect to data, is proven. Secondly, the theory is generalized to matrix-valued interpolation, but then only allowing for covariance-type interpolation conditions. Again, uniqueness and smoothness with respect to data is proven. Three algorithms are presented. Firstly, a refinement of a previous algorithm allowing for multiple as well as matrix-valued interpolation in an optimization framework is presented. Secondly, an algorithm capable of solving the boundary case, that is, with spectral zeros on the unit circle, is given. This also yields an inherent numerical robustness. Thirdly, a new algorithm treating the problem with both cepstral and covariance conditions is presented. Two design paradigms have sprung out of the complexity constrained analytical interpolation theory. Firstly, in robust control it enables low degree Hinf controller design. This is illustrated by a low degree controller design for a benchmark problem in MIMO sensitivity shaping. Also, a user support for the tuning of controllers within the design paradigm for the SISO case is presented. Secondly, in ARMA estimation it provides unique model estimates, which depend smoothly on the data as well as enables frequency weighting. For AR estimation, a covariance extension approach to frequency weighting is discussed, and an example is given as an illustration. For ARMA estimation, simultaneous cepstral and covariance matching is generalized to include prefiltering. An example indicates that this might yield asymptotically efficient estimates. / QC 20100928
96

A Model for Multiperiod Route Planning and a Tabu Search Method for Daily Log Truck Scheduling

Holm, Christer, Larsson, Andreas January 2004 (has links)
The transportation cost of logs from forest to customers is a large part of the overall cost for the Swedish forestry industry. Finding good routes from harvesting points to saw and pulp mills is a complex task, where the total number of feasible routes is extremely high. In this thesis we present two methods for log truck scheduling. The first is to, from a given set of routes, find the most valuable subset that fulfils the customers demand. We use a model that is similar to the set partitioning problem and a method that is referred to as a composite pricing coupled with Branch and Bound. The composite pricing based method prices the routes (columns) and chooses the most valuable ones that are then added to the LP relaxation. Once an LP optimum is found, the Branch and Bound method is used to find an integer optimum solution. We have tested this on a case of realistic size. The second method is a tabu search heuristic. Here, the purpose is to create efficient and qualitative routes from a given number of trips (referred to as predefined trips). From a start solution tabu search systematically generates new solutions. This method was tested on a small problem and on a five times larger problem to study how the size of the problem affected the result. It was also tested and compared on two cases in which the backhauling possibilities (i.e. instead of traveling empty the truck picks up another load on the return trip) had and had not been studied. The composite pricing based method and the tabu search method proved to be very useful for this kind of scheduling.
97

Efficient Updating Shortest Path Calculations for Traffic Assignment

Holmgren, Johan January 2004 (has links)
Traffic planning in a modern congested society is an important and time consuming procedure. Finding fast algorithms for solving traffic problems is therefore of great interest for traffic planners allover the world. This thesis concerns solving the fixed demand traffic assignment problem (TAP) on a number of different transportation test networks. TAP is solved using the Frank-Wolfe algorithm and the shortest path problems that arise as subproblems to the Frank-Wolfe algorithm are solved using the network simplex algorithm. We evaluate how a number of existing pricing strategies to the network simplex algorithm performs with TAP. We also construct a new efficient pricing strategy, the Bucket Pricing Strategy, inspired by the heap implementation of Dijkstra's method for shortest path problems. This pricing strategy is, together with the actual use of the network simplex algorithm, the main result of the thesis and the pricing strategy is designed to take advantage of the special structure of TAP. In addition to performing tests on the conventional Frank-Wolfe algorithm, we also test how the different pricing strategies perform on Frank-Wolfe algorithms using conjugate and bi-conjugate search directions. These test results show that the updating shortest path calculations obtained by using the network simplex outperforms the non-updating Frank-Wolfe algorithms. Comparisons with Bar-Gera's OBA show that our implementation, especially together with the bucket pricing strategy, also outperforms this algorithm for relative gaps down to 10E-6.
98

Investigating human trafficking for sexual exploitation: from ‘lived experiences’ towards a complex systems understanding

Van der Watt, Marcel January 2018 (has links)
Human trafficking for sexual exploitation, as the most documented type of trafficking both internationally and in South Africa, was the focus of this study as it poses significant challenges to response efforts whilst remaining a crime of vast impunity. At the centre of this study was the researcher’s curiosity-infused endeavour to understand the lived experiences of multipronged stakeholders who have first-hand experience of the investigation into human trafficking for sexual exploitation. A qualitative approach and the use of hermeneutic phenomenology within a broader postmodernist and constructivist positioning served as the catalyst for generating novel insights. Numerous formal and informal conversations over the 5-year research period, site visits to multiple sex trade locations around South Africa and 91 in-depth and unstructured interviews with participants from 15 different vantage points were conducted. Five themes were identified from participants’ lived experiences as they related to the investigation of human trafficking for sexual exploitation. These were Theme 1: Sex Trade, Human Trafficking and Organised Crime; Theme 2: Combating Human Trafficking for Sexual Exploitation; Theme 3: Victims of Human Trafficking for Sexual Exploitation; Theme 4: Corruption and Compromise; and Theme 5: The Social Context and Scope of the Problem. A rich and in-depth presentation of participants’ lived experiences from an emic point of view was made. Knowledge generated include the revelation of problematic claims by preservationists around the nature of the sex trade in South Africa, insights into complexities intrinsic to human trafficking for sexual exploitation and multi-layered challenges associated with investigations into the crime. At the apex of the study was the deconstruction of complex systems theory and its application to the phenomenological essence of participants’ lived experiences. A proposed application of the theory was suggested for a more agile, robust and effective multipronged investigation strategy to combat human trafficking for sexual exploitation. A strong argument is made for a ‘whole’ and non-reductionist approach to investigations that continuously considers both the complexity of the crime and the day-to-day realities of the stakeholders who contribute to the multipronged investigation into human trafficking for sexual exploitation. / Ukurhweba ngabantu ngeenjongo zokubaxhaphaza ngokwesondo, lolona didi lorhwebo lokuxhaphaza ekubhalwe ngalo kakhulu kwihlabathi jikelele nakuMzantsi Afrika. Esi sifundo sigxile kolu rhwebo njengoko lucela umngeni kwimizamo yokusabela lo gama ilulwaphulo mthetho olungalawulekiyo. Esizikithini sesi sifundo yayingumdla womphandi ukuqonda ngamava abo bathatha inxaxheba ekuphandeni ngorhwebo lokuxhaphaza ngokwesondo. Kukhethwe ufundo oluqwalasela umgangatho nokusetyenziswa kwesimbo sokutolika iimeko ezikhoyo kwilizwe elisemva kwelale mihla siphila kuyo njengeyona nqobo eya kuveza iimbono ezingaqhelekanga. Kwabanjwa inqwaba yeencoko ezisesikweni nezingekho sikweni ezenziwe kwisithuba seminyaka yophando engaphaya kwemihlanu, kwatyelelwa kwiindawo zorhwebo lokuxhaphaza ngokwesondlo ezikhoyo eMzantsi Afrika, kwabanjwa nodliwano ndlebe olunzulu lungaqingqwanga olungama-91 nabantu abakwiindawo zomdla ezili-15. Kwabonakala imixholo emihlanu esuka kumava abathathi nxaxheba malunga nophando ngorhwebo lokuxhaphaza ngesondo. Le mixholo yile: Umxholo woku-1: Urhwebo Lwesondo, Urhwebo Lokuxhaphaza Abantu, Nolwaphulo Mthetho Olucwangcisiweyo; Umxholo wesi-2: Ukulwa Urhwebo lokuxhaphaza abantu Ngenjongo Yesondo; Umxholo wesi-3: Amaxhoba Orhwebo Lokuxhaphaza Abantu Ngenjongo Yesondo; Umxholo wesi-4: Ubuqhophololo Nokunikezela; kunye noMxholo wesi-5: Imeko Yezentlalo Nomthamo Wengxaki. Kwenziwa inkcazelo enzulu netyebileyo yamava abathathi nxaxheba evelelwa ngokwendlela abantu bendawo abacinga nabazibona ngayo izinto. Ulwazi olufunyenweyo luquka izimvo eziyingxaki zabantu abakhuthaza ukugcinwa kwezinto zinjengoko zinjalo, malunga nohlolo olululo lorhwebo ngesondo eMzantsi Afrika, izimvo ngobunzima obubuthume kurhwebo lokuxhaphaza abantu ngenjongo yesondo kunye nemingeni emininzi eyayanyaniswa nophando lolwaphulo mthetho. Encochoyini yesi sifundo kukuhlakaza ingcingane exhakaxhaka yeenkqubo nokusetyenziswa kwayo kwiimeko ezikhoyo kumava abathathi nxaxheba. Kwacetyiswa indlela yokusebenzisa le ngcingane ekwenzeni icebo elinamandla nelisebenzayo lokulwa urhwebo lokuxhaphaza abantu ngenjongo yesondo. Kuthethelwa indlela yokusebenza ‘epheleleyo’ nengacuthi nto ekuqhubeni uphando v olusoloko luthathela ingqalelo ubuxhakaxhaka bolwaphulo mthetho namava emihla ngemihla abathathi nxaxheba abafaka isandla kuphando oluvelela iinkalo ezininzi kurhwebo lokuxhaphaza abantu ngenjongo yesondo. / Ukushushumbiswa kwabantu ukuze baxhashazwe ngokocansi, njengohlobo lokushushumbisa oluqoshwe phansi ngokudlula zonke ezinye izinhlobo emhlabeni wonke kanye naseNingizimu Afrika, yikona okugxilwe kukho kakhulu kulolu cwaningo njengoba kuyikona okungadala izingqinamba ezinkulu emizamweni yokubhekana nakho kube futhi kuyilona hlobo lobugebengu olungajeziswa kangako. Okunguwona mgomo walolu cwaningo yimizamo yomcwaningi egqugquzelwa ngukufuna kwakhe ukwazi ukuze aqonde lokho okubonwe ngababandakanyekayo abahlukahlukene abebebhekene ngqo nokuphenywa kodaba lokushushumbiswa kwabantu ukuze baxhashazwe ngokocansi. Kusetshenziswe indlela yokwenza ephathelene nokuqoqwa kwemininingwane engamaqiniso nokusetshenziswa kohlobo locwaningo olwahlukile kulolo olubheka ukwenzeka kwezinto ngokwemvelo maqondana nokuhleleka kwezinto ngokwesikhathi esilandela esezinto zesimanjemanje, nangendlela elandela umumo othize, njengegqugquzela ubukhona bokuqonda okuhlaba umxhwele ngokungajwayelekile. Kube khona izingxoxo eziningi ezihleliwe nezingahlelwanga ezenzeke esikhathini esiyiminyaka emihlanu yocwaningo, kwavakashelwa izizinda eziningi ezindaweni okuhwetshelwana kuzo ngocansi eziseNingizimu Afrika, kwaphinde kwaba nezingxoxo ezingama-91 ezijulile ngokuphonsa imibuzo engahleliwe ngokusemthethweni kubabambiqhaza abavela ezindaweni eziyi-15 ezilungele lolu cwaningo. Kuhlonzwe izingqikithi ezinhlanu eziqhamuke kulokho okubonwe ngababambiqhaza ngokuhlobana kwabo nophenyo lokushushumbiswa kwabantu ukuze baxhashazwe ngokocansi. Yilezi, Ingqikithi 1: Ukuhweba Ngocansi, Ukushushumbiswa Kwabantu Nobugebengu Obuhleliwe; Ingqikithi 2: Ukulwisana Nokushushumbiswa Kwabantu Ukuze Baxhashazwe Ngokocansi; Ingqikithi 3: Izisulu Zokushushumbiswa Ukuze Zixhashazwe Ngokocansi; Ingqikithi 4: Inkohlakalo Nokwenza Okungahambisani Nawe; neNgqikithi 5: Indikimba Kwezenhlalo Nobubanzi Benkinga. Kube sekwethulwa ngokucebile nangokujulile okubonwe ngababambiqhaza ngokwencazelo ehambisana nohlobo lwesifundo. Ulwazi olutholakele lubandakanya ukuvela kwalokho okuyinkinga okushiwo yilabo abalwela ubukhona bohwebo lwezocansi eNingizimu Afrika, ukuqondwa kwalokho okungekho lula ukukuqonda okuphathelene vii nokushushumbiswa kwabantu ukuze baxhashazwe ngokocansi kanye nezingqinamba ezishiyana ngokwezigaba ezihambisana nophenyo lwalobu bugebengu. Ekujuleni kocwaningo kube khona ukuhlaziya okubanzi ngokuhlakaza izinhlelo zezinzululwazi okungekho lula ukuziqonda nokusetshenziswa kwazo kulokho okusemqoka okubonwe ngababambiqhaza. Kuhlongozwe ukuba kusetshenziswe isu elisheshayo, elishubile nelizosebenza ngempumelelo elihlukene izigaba eziningi ezibheka konke elizolwisana nokushushumbiswa kwabantu ukuze baxhashazwe ngokocansi. Ukudingida kabanzi ngendlela 'ephelele' nengancike ndawo okumele ilandelwe uma kuphenywa nezobheka kokubili ukungabi lula kobugebengu okubhekenwe nabo kanye nokubonwa imihla ngemihla ngababambiqhaza abasiza ngokuthile ophenyweni olubheka okuningi okwahlukahlukene maqondana nokushushumbiswa kwabantu ukuze baxhashazwe ngokocansi. / Criminology and Security Science
99

A practical approach toward architectures for open computational systems

Carlsson, Jimmy January 2002 (has links)
By means of a systemic approach toward analysis and design of complex systems, we introduce the issue of implementing open computational systems on service-oriented architectures. We start by studying general systems theory, as it accounts for analysis and modeling of complex systems, and then compare three different implementation strategies toward system implementation. As such, the comparison is grounded in the notion of supporting architectures and, more specifically, in the practical case of a service-oriented layered architecture for communicating entities (SOLACE). / More material can be found on http://www.soclab.bth.se
100

Att vara syskon till ett barn med neuropsykiatrisk funktionsnedsättning : En kvalitativ intervjustudie / Growing up with a sibling with neuropsychiatric disability : A qualitative interview study

Olofsson, Ebba, Müller, Nicole January 2020 (has links)
Through practical experiences in social work we have found that siblings of children with neuropsychiatric disability are being left behind in family treatment. We have also identified  a knowledge gap through previous research in how siblings experience their role and relationships within the family. The purpose of this study is to establish an understanding of how neuropsychiatric disability affects the siblings in the family. The siblings referred to in this qualitative study, who we got in touch with through social media, have been interviewed through six semi-structured interviews. Furthermore, the answers have been analyzed through systems theory. The results show that the siblings have taken great responsibility for their sibling and taken a step back as the sibling with neuropsychiatric disability had extensive needs that required a lot of attention and care from their parents.

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