We introduce a new insurance instrument allowing retirees to hedge against risk of mortality and risk of default. At retirement, the retiree is allowed to purchase an annuity that provides a defaultable income stream over his lifetime. The time of mortality and time of default are both uncertain, but are accompanied by determined hazard rates. The retiree will make consumption and investment choices throughout his lifetime, which have certain restrictions: the retiree can never enter a bankruptcy state (negative total wealth), and the investment choices are made in a risk-free financial instrument (such as a treasury bill or bond) and a risky instrument (such as commodities or stock). The retiree also makes insurance premium payments which hedge against mortality and default risks simultaneously. This new form of insurance is one which can be implemented by financial institutions as a means for retirees to protect their illiquid assets. In doing so, we calculate the optimal annuity rate a retiree should purchase to maximize his utility of consumption and bequest.Throughout the paper, we develop stochastic control models for a retiree's optimal investment and consumption policies over an uncertain planning horizon in several models which may or may not allow for insurance purchases. We find exact solutions to several models, and apply dynamic programming and the logarithmic transformation to other models to find numerical solutions when constraints are needed. We also analyze the effects of loading on insurance, analyzing the effects of more expensive insurance on the retiree's control policies and value functions. In particular, we will consider the model in which the retiree can purchase life insurance and credit default insurance (in the form of a credit default swap, or CDS) separately to hedge against life events. CDS's do not exist for annuities, but we extend this model by incorporating life insurance and the CDS into a single entity, which can be a viable, and realistic, option to hedge against risk. This model is beneficial in providing a solution to the annuity problem by showing that minimal annuity purchase is optimal.

Nöje är en viktig aspekt i spel som spelas för underhållning. För att kontrollera om ett spel är roligt krävs speltestning, men i denna process uppstår det flera nivåer av störvariabler som påverkar tolkningen av resultatet. Det tycks alltså finnas ett behov av objektiva och mätbara variabler i speltestning. Därför ämnade denna studie besvara frågan om vad sambandet mellan antal misslyckanden och upplevt nöje är. I undersökningen bjöds 18 respondenter in för att spela ett pusselspel, som hade konstruerats enligt etablerade designprinciper och med syftet att tydligt visa när spelarna gör felaktiga handlingar som resulterar i misslyckanden. Därefter besvarade de inbjudna respondenterna på en frågeenkät, som utformades enligt Sweetser och Wyeths GameFlow-modell, för att uppskatta deras upplevda nöje. Två potentiella samband kunde uppmärksammas: Pusselspel tycks ha en mängd misslyckanden, ett gyllene intervall, som resulterar i mest nöje, och gradvisa förändringar i antal misslyckanden i nivåer som följer varandra ökar spelarens upplevelse av nöje. / <p>Det finns övrigt digitalt material (t.ex. film-, bild- eller ljudfiler) eller modeller/artefakter tillhörande examensarbetet som ska skickas till arkivet.</p><p>There are other digital material (eg film, image or audio files) or models/artifacts that belongs to the thesis and need to be archived.</p>

Since the 1970s, the Rubik’s Cube puzzle has intrigued millions of people. It did not take long until people tried to solve the cube as fast as possible, and started to compete. However, in recent years, a new trend of robots solving the cube has flourished. The purpose of this project was to investigate time and precision aspects of a Rubik’s cube solving robot. A four armed robot was designed and a system was built. The construction made it possible to first scan the cube using a webcam and solve the cube by letting the robot perform the movements necessary for solving. Differences in time for different scrambles was analyzed as well as the robot’s precision. Since the robot only had four arms, the results showed differences in turning the up- and downside of the cube. To get access to these sides, the robot had to perform a flip motion. Since the software used was not optimized to minimize these moves there were differences in solving time. Moreover, the robot’s precision differed depending on its setup and how fast it was programmed to go. Two different setups was compared, one being slow and having big margins between each move and the other one being more rapid. Both setups worked, although calibration was more crucial for the faster one. / Sedan 70-talet har Rubiks kub fängslat miljontals människor. Det tog inte lång tid innan kampen om att lösa kuben så snabbt som möjligt uppstod och med det även tävlingar. Under de senaste åren har däremot en ny trend kommit med robotar som löser kuben. Projektets syfte var att undersöka tids- och precisionsaspekter för en robot som löser en Rubiks kub. I det här projeketet byggdes en fyrarmad robot med uppgift att lösa kuben. Systemet skapades så att kuben först skannas med en webkamera och sedan sätts på plats i roboten som löser kuben. Skillnader i tid för olika blandningar samt robotens precision analyserades. Eftersom roboten konstruerades med fyra armar var det tydliga skillnader i tid för upp- och nersidans drag. För att få tillgång till dessa sidor var hela kuben tvungen att roteras. Eftersom mjukvaran som användes inte var optimerad för att minimera nyttjandet av dessa rörelser varierade lösningstiderna. Dessutom var det skillnader i robotens precision beroende på systemets kalibrerade hastighet. Två olika inställningar jämfördes där en var långsammare med större marginaler mellan varje drag och den andra var snabbare. Båda fungerade för att lösa kuben men kalibreringen blev mycket avgörande för den snabbare inställningen.

Essay I: This essay provides an overview of the history of the Swedish pension system. Starting with the implementation of the public pension system in 1913, it outlines the key components of each major pension reform up until today along with a discussion of the main trade-offs and concerns that policy makers have faced. It also describes the historical background of the four largest occupational pension plans in Sweden and the mutual influence between these plans and the public pension system.        Essay II: Despite the fact that the increasing involvement of the private sector in pension provision has brought more flexibility to the pay-out phase of retirement, little is known about the characteristics of those who choose to annuitize their pension wealth and those who do not. I combine unique micro-data from a large Swedish occupational pension plan with rich national administrative data to study the choice between life annuities and fixed-term payouts with a minimum payout length of 5 years for 183,000 retiring white-collar workers. I find that low accumulation of assets is strongly associated with the choice of the 5-year payout. Consistent with individuals selecting payout length based on private information about their mortality prospects, individuals who choose the 5-year payout are in worse health, exhibit higher ex-post mortality rates and have shorter-lived parents than annuitants. Individuals also seem to respond to large, tax-induced changes in annuity prices.            Essay III: This essay estimates the causal effect of postponing retirement on a wide range of health outcomes using Swedish administrative data on cause-specific mortality, hospitalizations and drug prescriptions. Exogenous variation in retirement timing comes from a reform which raised the age at which broad categories of Swedish local government workers were entitled to retire with full pension benefits from 63 to 65. The reform caused a remarkable shift in the retirement distribution of the affected workers, increasing the actual retirement age by more than 4.5 months. Instrumental variable estimation results show no effect of postponing retirement on the overall consumption of health care, nor on the risk of dying early. There is evidence, however, of a reduction in diabetes-related hospitalizations and in the consumption of drugs that treat anxiety. Essay IV (with Per Engström): The consumption based method to estimate underreporting among self-employed, introduced by Pissarides and Weber (1989), is one of the workhorses in the empirical literature on tax evasion/avoidance. We show that failure to account for transitory income fluctuations in current income may overestimate the degree of underreporting by around 40 percent. Previous studies typically use instrumental variable methods to address the issue. In contrast, our access to registry based longitudinal income measures allows a direct approach based on more permanent income measures. This also allows us to evaluate the performance of a list of instruments widely used in the previous literature. Our analysis shows that capital income is the most suitable instrument in our application, while education and housing related measures do not seem to satisfy the exclusion restrictions.

With the growth of wireless technologies in sectors like the military, aviation, etc, there is a need to determine the authenticity of a genuine user. Today's conventional authentication mechanisms are based on three factors: knowledge, possession and biometrics. These factors are prone to theft, hardware failure, expensive, etc. Consequently, there is a need of a stronger solution. One such solution is Location Based Authentication that considers the location information of a user. The location information is time based and thus hard to steal. However, accuracy of the GPS, signal strength inside the building, etc, affects its potential. Consequently, there is a need to address alternatives. One such alternative is to implement a puzzle-based authentication scheme based on the location information. In the proposed scheme, the server asks dynamic location-based questions and the client answers them based on the proposed route of travel. This scheme strengthens the current authentication mechanisms.

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" We designed an interactive 3D user interface system to perform object modeling in virtual environments. Expanding on existing 3D user interface techniques, we integrate low-cost human gesture recognition that endows the user with powerful abilities to perform complex virtual object modeling tasks in an immersive game setting. Much research has been done to explore the possibilities of developing biosensors for Virtual Reality (VR) use. In the game industry, even though full body interaction techniques are involved in modern game consoles, most of the utilizations, in terms of game control, are still simple. In this project, we extended the use of motion tracking and gesture recognition techniques to create a new 3D UI system to support immersive gaming. We set a goal for the usability, which is virtual object modeling, and finally developed a game application to test its performance. "

This thesis applies classical optimization problems such as assignment or set-covering problem on logical puzzles or brainteasers. Listed in the first part are mathematical model, description and typical example of each optimization problem used in this thesis. The second part contains these models applied to the particular brainteasers for example Sudoku or Einstein's Puzzle. Exercises are divided into simpler and more complex ones. There is specification, source and a described method of solution stated for each of them. The calculation examples use Lingo or MS Excel or both. The aim is to show the possibility to address logical puzzles and brainteasers with the use of optimization problems, and thus confirm the wide possibilities of using these models. These examples can clarify and diversify the curriculum.

Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-05-14T12:11:03Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_PropondoProblemaForrageio.pdf: 644586 bytes, checksum: d2ebb247aee32117aea92d0cdebf87f3 (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-09-04T12:21:17Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_PropondoProblemaForrageio.pdf: 644586 bytes, checksum: d2ebb247aee32117aea92d0cdebf87f3 (MD5) / Made available in DSpace on 2014-09-04T12:21:17Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_PropondoProblemaForrageio.pdf: 644586 bytes, checksum: d2ebb247aee32117aea92d0cdebf87f3 (MD5) Previous issue date: 2003 / O presente estudo analisou a influência de um simples aparelho que simulou o forrageamento ativo por insetos, funcionando como um alimentador enigmático denominado puzzle, sobre o comportamento de duas espécies de calitriquíneos (Callitrichinae, Primates) mantidos em cativeiro no Centro Nacional de Primatas (CENP). Buscou-se comparar a reação das duas espécies frente ao aparelho proposto, e verificar a viabilidade deste artifício no enriquecimento ambiental das condições de cativeiro para estes primatas. Foram utilizados três casais de Saguinus imperator, conhecido por sagui imperador e três casais de Callithrix penicillata, conhecido por mico estrela, as comparações foram feitas entre as espécies e entre os sexos. Foram gravadas através de vídeo cassete seções de observação com duração de três horas, divididas em dois períodos, um controle (ausência do puzzle) e outro experimental (presença do puzzle), com um total de 36 horas de observação para cada casal. As sessões de controle foram usadas para calcular a linha base do orçamento de atividade para comparações com padrões de comportamento durante as sessões experimentais. As fitas foram transcritas, e todos os eventos de comportamento foram cronometrados, e registrados as medidas da freqüência e duração de eventos. Nas duas espécies a manipulação do puzzle não alcançou uma proporção de tempo muito elevada, porém demonstrou uma diferença clara entre as duas espécies, ocupando 3,96% do tempo total dos micos e 1,99% do tempo dos saguis. Os micos gastaram com repouso, durante as seções experimentais, 17% menos tempo em comparação com a situação controle. Considerando que a ociosidade reduziu em menos de 7% nos saguis, com a atividade geral aumentada em 10%. Entre os sexos, notou-se uma inversão, onde as fêmeas de sagui tiveram um aumento de 18% na ociosidade e queda de 14% na atividade, enquanto as fêmeas de mico tiveram uma diminuição nas duas categorias de pouco menos de 10%. Os machos responderam mais ao puzzle, os saguis aumentaram em 58% a atividade e diminuíram em 23% a ociosidade, os micos aumentaram a atividade em 4% e diminuíram a ociosidade em menos de 10%. Todos os animais aprenderam a manipular o equipamento e capturar os insetos, sendo que os micos tiveram um maior êxito no número de larvas capturadas, superando aos saguis em cerca de 54% de seu índice. As fêmeas tiveram mais êxitos em ambas as espécies, porém superficialmente nos micos. Em contraste, nos saguis as fêmeas foram 16% mais prósperas que os machos. O puzzle foi eficiente em enriquecer o ambiente cativo dos animais e estimular o comportamento manipulativo, sendo um instrumento importante na busca do bem estar para as duas espécies. / This study analysed the influence of a simple insect foraging puzzle on the behaviour of two callitrichine species (Callitrichinae, Primates) maintained in captivity at the National Primate Centre (CENP), in Ananindeua, in the Brazilian state of Para. In addition to comparing the two species, the study aimed to evaluate the viability of the puzzle as a strategy of environmental enrichment for these primates in captivity. Three adult pairs of each species – the pencil-tufted marmoset (Callithrix penicillata) and the emperor tamarin (Saguinus imperator) – were included in the study, which also focussed differences between genders. Observations were conducted through the video-taping of three-hour sessions, divided into control (puzzle absent) and experimental (puzzle present) periods, with a total of 36 hours of observation for each pair. Control sessions were used to calculate baseline activity budgets for comparisons with behaviour patterns during experimental sessions. Tapes were transcripted, and all behaviour events were timed, providing measures of both the frequency and duration of events. The puzzle did not have a major effect on general activity budgets, but its effect was clearly different in each species, with manipulation of the puzzle accounting for 3.96% of the time of the marmosets, but only 1.99% of that of the tamarins. During experimental sessions, the marmosets spent 17% less time at rest in comparison with their baseline budget, whereas rest was reduced by less than 7% in the tamarins, with general activity increasing 10%. These changes varied considerably when comparing genders, however – male tamarins presented a 58% increase in general activity and a 23% reduction in rest, whereas these values were 4% and 10%, respectively, in male marmosets. Female tamarins presented an opposite pattern, with rest increasing 18% and general activity falling 14%, while female marmosets had a reduction in both categories by a little less than ten percent. All the animals learned to manipulate the puzzle and capture insects, although the marmosets were far more persistent, capturing 54% more insects, on average, than the tamarins. Females were more successful in both species, but only marginally so in the marmosets. In the tamarins, by contrast, females were 16% more successful than males. Overall, the puzzle proved to be efficient as a means of enriching the captive environment of both species, by stimulating manipulative behaviour and reducing inactivity.

This thesis examines the problem of the automated re-assembly of jigsaw puzzles. The objectives of this research are as follows: to provide a clear statement of the jigsaw puzzle re-assembly problem; to find out which solution technique is best suited to this problem; to determine the level of sensitivity of the proposed solution technique when solving different variations of this problem; and to explore solution methods for solving incomplete jigsaw puzzles (puzzles with missing pieces). The jigsaw puzzle re-assembly problem has been investigated only intermittently in the research literature. This work presents an extensive examination of the suitability and efficiency of the standard solution techniques that can be applied to this problem. A detailed comparison between different solution methods including Genetic Algorithms, Simulated Annealing, Tabu Search and Constraint Satisfaction Programming, shows that a constraint-based approach is the most efficient method of generating solutions to the jigsaw puzzle problem. The proposed re-assembly algorithm is successful. Consequently, it can be used in development of automated solution generators for other problems in the same domain, thus creating new theoretical and applied directions in this field of research. One potential theoretical line of research concerns jigsaw puzzles that do not have a complete set of puzzle pieces. These incomplete puzzles represent a difficult aspect of this problem that is outlined but can not be resolved in the current research. The computational experiments conducted in this thesis demonstrate that the proposed algorithm being optimised to re-assemble the jigsaw puzzles is not efficient when applied to the puzzles with missing pieces. Further work was undertaken to modify the proposed algorithm to enable efficient re-assembly of incomplete jigsaw puzzles. Consequently, an original heuristic strategy, termed Empty Slot Prediction, was developed to support the proposed algorithm, and proved successful when applied to certain sub-classes of this problem. The results obtained indicate that no one algorithm can be used to solve the multitude of possible scenarios involved in the re-assembly of incomplete jigsaw puzzles. Other variations of the jigsaw puzzle problem that still remain unsolved are presented as avenues for future research. The solution of this problem involves a number of procedures with significant applications in other computer-related areas such as pattern recognition, feature and shape description, boundary-matching, and heuristic modelling. It also has more practical applications in robotic vision and reconstruction of broken artefacts in archaeology.