Θέμα της παρούσας εργασίας είναι η υλοποίηση και εξομοίωση δίκαιων αλγόριθμων χρονοπρογραμματισμού σε Grids και η σύγκρισή τους με κλασικούς αλγόριθμους χρονοπρογραμματισμού. Η βασική ιδέα πίσω από την τεχνολογία Grid και τις υπηρεσίες που παρέχει είναι η ενοποίηση υπολογιστικών και αποθηκευτικών πόρων και η συνολική θεώρηση τους από τους χρήστες. Με τον τρόπο αυτό γίνεται δυνατή η ανάπτυξη πολύπλοκων και απαιτητικών εφαρμογών, τόσο στον χώρο της επιστημονικής έρευνας, όσο και στα πλαίσια της παραγωγής εμπορικών λύσεων. Ένα τέτοιο σύστημα απαιτεί διαμοιρασμό των υπολογιστικών και άλλων πόρων καθώς και μεγάλες ταχύτητες σύνδεσης μεταξύ τους. Οι αλγόριθμοι χρονοπρογραμματισμού αναλαμβάνουν τον αποδοτικό διαμοιρασμό των πόρων ώστε να επιτυγχάνεται καλύτερη ποιότητα υπηρεσίας. Η αποτελεσματικότητα ενός αλγόριθμου χρονοπρογραμματισμού εξαρτάται από την συνάρτηση που θέλουμε να βελτιστοποιήσουμε, που με τη σειρά της εξαρτάται από τεχνο-οικονομικά κριτήρια. Στην προσπάθεια βελτιστοποίησης της εκάστοτε συνάρτησης ευνοούνται κάποιες προς εκτέλεση διεργασίες έναντι άλλων. Ένας δίκαιος αλγόριθμος χρονοπρογραμματισμού όμως θα πρέπει να συμπεριφέρεται με τον ίδιο τρόπο σε όλες τις διεργασίες ανεξαρτήτως των χαρακτηριστικών τους. Στην εργασία που θα παρουσιάσουμε, αναλύουμε δύο δίκαιους αλγόριθμους χρονοπρογραμματισμού, τον Fair Completion Time (Ordering) και τον Fair Completion Time Estimation (Assignment). Κατόπιν τους υλοποιούμε και τους εξομοιώνουμε με το GridSim Toolkit και συγκρίνουμε την απόδοση τους με κλασικούς αλγόριθμους χρονοπρογραμματισμού. / The subject of this thesis is the implementation and simulation of fair scheduling algorithms applied on Computational Grids and their comparison with the classic scheduling algorithms. The basic idea of the Grid Technology and the services it provides, is the unification of computational and storage resources. This way it is possible to serve sophisticated applications, in fields like scientific research and trading. A Grid Network demands the sharing of the computational and storage resources, and high bandwidth connections between them. Scheduling algorithms are responsible for the efficient assignment of tasks to resources for better quality of service. Evaluating the efficiency of a scheduling algorithm depends on a utility function that we seek to optimize which in turns depends on techno-economic criteria. As a result of trying to optimize the utility function, some tasks with specific characteristics are favoured against others. A fair scheduling algorithm however should treat all tasks in the same way regardless of their characteristics. In this thesis we study the Fair Completion Time Ordering Algorithm and suggest a new fair scheduling algorithm called Fair Completion Time Estimation Assignment Algorithm. We implement and simulate these algorithms using the GridSim Toolkit and compare them with the classic scheduling algorithms.

Image completion is a process of removing an area from a photograph and replacing it with suitable data. Earlier methods either search for this relevant data within the image itself, or extends the search to some form of additional data, usually some form of database. Methods that search for suitable data within the image itself has problems when no suitable data can be found in the image. Methods that extend their search has in earlier work either used some form of database with labeled images or a massive database with photos from the Internet. For the labels in a database to be useful they typically needs to be entered manually, which is a very time consuming process. Methods that uses databases with millions of images from the Internet has issues with copyrighted images, storage of the photographs and computation time. This work shows that a small database of the user’s own private, or professional, photos can be used to improve the quality of image completions. A photographer today typically take many similar photographs on similar scenes during a photo session. Therefore a smaller number of images are needed to find images that are visually and structurally similar, than when random images downloaded from the internet are used. Thus, this approach gains most of the advantages of using additional data for the image completions, while at the same time minimizing the disadvantages. It gains a better ability to find suitable data without having to process millions of irrelevant photos.

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In 2008, state legislatures provided $6 billion in financial aid to 2 million low-income young adults. When low-income young adults receive state financial aid and do not complete college, states lose their investment because fewer people with degrees will contribute to the state's economy. Declining states' budgets have led to (a) the rising cost of higher education, (b) state merit-based aid that has targeted nonminority students from affluent backgrounds, and (c) state need-based aid that has targeted students further along in their college career. State need- and merit-based aid may contribute to the lack of college completion among low-income freshman students who rely on financial aid. The purpose of this study was to explore the differences between state need- and merit-based aid as enrollment factors of low college completion among low-income students in the U.S. This study was grounded on Tinto's model of social integration. Secondary data collected by the National Center for Education Statistics on 101,000 freshmen who attended 1,360 postsecondary institutions in 2003-04 and 2008-09 were used for this study. Logistic regression was used to test and compare two models. Logistic regression tested the relationship between the predictor variables of state need- and merit-based aid and degree completion. This study's results revealed that state merit-based aid had a greater predictive value than state need-based aid as enrollment factors of college completion among low-income young adults. This study contributes to positive social change by providing state policy makers with research results to evaluate and formulate state financial aid policies that will increase access to financial aid and college completion rates among low-income freshman students.

College degree attainment benefits both private citizens and society. Historically, degree attainment rates have differed based on students’ race, income, and parental education. Along with differences in degree attainment rates, time to degree has been increasing for all students nationally. Increased time to degree has adverse effects for students as it increases the cost of a degree and decreases future earnings through a delayed entry into the workforce.In recent years, colleges and universities have implemented programs to address challenges with graduation rates at their institutions and improve on-time degree completion. Beginning in 2014, a large public university located in the Mid-Atlantic region of the United States, implemented an on-time degree completion program to address its four-year bachelor’s degree completion rate. In addition to increased academic support for all program participants, up to 500 students with high-financial per cohort were given additional grant funding towards their cost of attendance. The Theory of Planned Behavior frames the process of shaping human behavior as the combination of changing the attitude towards completing the behavior, shifting norms to reflect desired outcomes, and reducing perceived barriers to behavior completion. The on-time degree completion program uses a participant contract and a series of checkpoints to encourage positive behavior, shown through research, to increase graduation rates: priority registration, meeting with an academic advisor, earning a minimum of 30 credits per academic year, and completing a degree audit. The current study analyzed the checkpoint and on-time degree completion data for three consecutive first-time, first-year cohorts at a large public university. The total number of participants included in the study totaled 13,323. Using a combination of descriptive and predictive statistics, I found that both checkpoint completion and on-time degree completion differed based on several participant characteristics, including academic preparation, race, family income, and parental education. However, even when controlling for participant background characteristics, checkpoint completion had a positive relationship to on-time degree completion. Therefore, while there are improvements to be made in the checkpoint completion rates and the equality of those outcomes, the program checkpoints predict on-time graduation. Further, for program participants who receive the program grant funding, there is a correlation between multiple years of grant funding and improvements in on-time graduation rate. Further research should be conducted to understand the reasons students fail to complete checkpoints and the barriers to checkpoint completion for some student groups. Additionally, for participants who were not retained until graduation, a study tracking participants’ degree completion across institutions would help explore the true degree completion rate for the participants, as opposed to at the individual institution. / Educational Administration

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O presente trabalho visa apresentar um panorama geral a respeito da terceira espécie de inadimplemento no Direito brasileiro, considerando os esforços da doutrina e da jurisprudência em nosso sistema jurídico no trato deste tema, bem como considerando aspectos relevantes colhidos na experiência estrangeira. Na tentativa de contribuir para debate, será apresentada uma proposição para a identificação dessa terceira espécie de inadimplemento no Direito brasileiro. / The present work aims to present an overview regarding the third kind of default in Brazilian law, considering the efforts of the doctrine and of the jurisprudence in our legal system in dealing with this issue, as well as considering relevant aspects gathered from the experience of foreign law. In an attempt to contribute to debate, a proposition will be presented for the identification of this third kind of default in Brazilian law.

O presente trabalho visa apresentar um panorama geral a respeito da terceira espécie de inadimplemento no Direito brasileiro, considerando os esforços da doutrina e da jurisprudência em nosso sistema jurídico no trato deste tema, bem como considerando aspectos relevantes colhidos na experiência estrangeira. Na tentativa de contribuir para debate, será apresentada uma proposição para a identificação dessa terceira espécie de inadimplemento no Direito brasileiro. / The present work aims to present an overview regarding the third kind of default in Brazilian law, considering the efforts of the doctrine and of the jurisprudence in our legal system in dealing with this issue, as well as considering relevant aspects gathered from the experience of foreign law. In an attempt to contribute to debate, a proposition will be presented for the identification of this third kind of default in Brazilian law.

[pt] Cerca de 50 por cento das reservas brasileiras de hidrocarbonetos estão localizadas na plataforma continental em lâminas de água superiores a mil metros. As temperaturas congelantes do fundo do mar tornam os problemas inerentes ao escoamento da produção de petróleo, ainda mais críticos. Entretanto, os desafios da garantia de escoamento, não são os únicos obstáculos para a produção de petróleo em águas ultra-profundas. Além dos aspectos relacionados à geologia e fatores econômicos, a decisão de desenvolvimento de um campo de petróleo no mar, adotando completação submarina ou seca, precisa ser respaldada por uma análise criteriosa dos problemas relacionados com a garantia de escoamento, principalmente em locações de águas profundas e ultra- profundas. Nestes cenários, a maior variação da energia potencial e conseqüente intensificação do efeito Joule-Thomson, contribuem de uma forma bem mais significativa para a queda de temperatura e pressão. Este trabalho objetiva promover a comparação entre um sistema de produção usando poços direcionais de grande afastamento, produzindo para uma unidade de completação seca e um sistema adotando poços com completação submarina, a 850, 1.550 e 2.300m de lâmina de água, avaliando os efeitos das perdas de carga e calor em um fluxo multifásico. Com o uso de completação molhada, é avaliada a máxima distância viável entre a zona produtora e a plataforma de produção, de forma a permitir o fluxo de hidrocarbonetos sem formação de cristais de parafina. Com base nos resultados alcançados, podemos tirar algumas conclusões importantes quanto à tendência dos sistemas de produção em águas profundas e ultra- profundas, que nortearão no futuro próximo o desenvolvimento de campos de petróleo na plataforma continental brasileira. / [en] Around 50 percent of the Brazilian reserves of hydrocarbons are located in the continental platform in water depths with more than one thousand meters. The freezing temperatures of the sea bottom make problems related to oil production, even more critical. However, the flow assurance challenges are not the only obstacles for the oil production in ultra-deep waters. Besides the aspects related to the geology and economical factors, the decision of development of an offshore oil field adopting a system with wet completion or with dry completion, needs to be supported by discerning analyses of the problems related to flow assurance aspects, mainly in deep and ultra-deep water locations. In these scenarios, a larger variation of the potential energy and consequent intensification of the Joule-Thomson effect, contribute in a much more significant way to the temperature and pressure drops. This work aims to promote the comparison between an oil production system using extended reach wells with a dry completion unit and another system with wet completion, at 850, 1.550 and 2.300m of water depth, evaluating the effects of pressure drop and heat loss in a multiphase flow. Using wet completion, it is evaluated the maximum feasible distances between the producing zone of the formation and the floating production unit, allowing the flow of hydrocarbons without interruption by the formation of paraffin crystals. Based on the reached results, we can reach some important conclusions regarding trend of production systems in deep and ultra-deep water, that will guide the development of oil fields in the near future in the Brazilian continental platform.

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