Sweden experiences heavy snowfall during the winter season and cost effective road maintenance is significantly affected by the routing of snowplows. The routing problem becomes more complex as the SwedishNational Road Administration (Vägverket) sets operational requirements such as satisfying a time window for each road segment. This thesis focuses on route optimization for snowplows after snowfall; to develop and implement an algorithm for finding combinations of generated routes which minimize the total cost. The results are compared to those stated in the licentiate thesis by Doctoral student Nima Golbaharan (2001). The algorithm calculates a lower bound to the problem using a Lagrangian master problem. A common subgradient approach is used to find near-optimal dual variables to be sent to a column-generation program which returns routes for the snowplows. A greedy heuristic chooses a feasible solution, which gives an upper bound to the problem. This entire process is repeated as needed. This method for routing snowplows produces favorable results with a relatively small number of routes and are comparable to Golbaharan's results. An interesting observation involves the allocation of vehicles in which certain depots were regularly over- or under-utilized. This suggests that the quantity and/or distribution of available vehicles may not be optimal.

Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required. In this thesis an optimization model is developed that simulates Nynas distribution of bitumen from the depots to the customers. The model is used to investigate the required vehicle fleet size for a number of different scenarios, that is with different depots closed down. The question to be answered is, thus, what depots could be closed without any dramatic increase in the required vehicle fleet size? Scenarios where customers are allocated an increased storage capacity are also studied. The distribution model that is developed is an inventory route planning problem. It is solved by column generation. Each column represents a route and is generated by a subproblem with restrictions on permitted working hours for the truck drivers. Integer solutions are generated heuristically. Simulations that have been performed with the model reveals interesting differences concerning how the distribution is handled in different parts of Sweden. In western Sweden the transportation planning works well, but the distribution in the central parts of the country could be planned in a better way. Results from simulations also show that the depots in Norrköping and Västerås could be closed down without increasing the vehicle fleet. Probably, the existing vehicle fleet size will be sufficient even with the Kalmar-depot closed down. Nevertheless, Nynas transportation suppliers will have to purchase new vehicles if the Sandarne-depot is to be closed. Another interesting conclusion that can be drawn from this thesis is that there is a potential for reducing the vehicle fleet size if the storage capacity is increased at a few chosen customers. A considerably small increase in the storage capacity at a few big customers that are located far from the depots will have a great effect.

No description available.

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.

<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>

<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>

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

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.

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.

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