Investments in space systems are substantial, indivisible, and irreversible, characteristics that make them high-risk, especially when coupled with an uncertain demand environment. Traditional approaches to system design and acquisition, derived from a performance- or cost-centric mindset, incorporate little information about the spacecraft in relation to its environment and its value to its stakeholders. These traditional approaches, while appropriate in stable environments, are ill-suited for the current, distinctly uncertain and rapidly changing technical, and economic conditions; as such, they have to be revisited and adapted to the present context. This thesis proposes that in uncertain environments, decision-making with respect to space system design and acquisition should be value-based, or at a minimum value-informed. This research advances the value-centric paradigm by providing the theoretical basis, foundational frameworks, and supporting analytical tools for value assessment of priced and unpriced space systems. For priced systems, stochastic models of the market environment and financial models of stakeholder preferences are developed and integrated with a spacecraft-sizing tool to assess the system's net present value. The analytical framework is applied to a case study of a communications satellite, with market, financial, and technical data obtained from the satellite operator, Intelsat. The case study investigates the implications of the value-centric versus the cost-centric design and acquisition choices. Results identify the ways in which value-optimal spacecraft design choices are contingent on both technical and market conditions, and that larger spacecraft for example, which reap economies of scale benefits, as reflected by their decreasing cost-per-transponder, are not always the best (most valuable) choices. Market conditions and technical constraints for which convergence occurs between design choices under a cost-centric and a value-centric approach are identified and discussed. In addition, an innovative approach for characterizing value uncertainty through partial moments, a technique used in finance, is adapted to an engineering context and applied to priced space systems. Partial moments disaggregate uncertainty into upside potential and downside risk, and as such, they provide the decision-maker with additional insights for value-uncertainty management in design and acquisition. For unpriced space systems, this research first posits that their value derives from, and can be assessed through, the value of information they provide. To this effect, a Bayesian framework is created to assess system value in which the system is viewed as an information provider and the stakeholder an information recipient. Information has value to stakeholders as it changes their rational beliefs enabling them to yield higher expected pay-offs. Based on this marginal increase in expected pay-offs, a new metric, Value-of-Design (VoD), is introduced to quantify the unpriced system's value. The Bayesian framework is applied to the case of an Earth Science satellite that provides hurricane information to oil rig operators using nested Monte Carlo modeling and simulation. Probability models of stakeholders' beliefs, and economic models of pay-offs are developed and integrated with a spacecraft payload generation tool. The case study investigates the information value generated by each payload, with results pointing to clusters of payload instruments that yielded higher information value, and minimum information thresholds below which it is difficult to justify the acquisition of the system. In addition, an analytical decision tool, probabilistic Pareto fronts, is developed in the Cost-VoD trade space to provide the decision-maker with additional insights into the coupling of a system's probable value generation and its associated cost risk.

The past decades have seen the state of the art in aerospace system design progress from a scope of simple optimization to one including robustness, with the objective of permitting a single system to perform well even in off-nominal future environments. Integrating flexibility, or the capability to easily modify a system after it has been fielded in response to changing environments, into system design represents a further step forward. One challenge in accomplishing this rests in that the decision-maker must consider not only the present system design decision, but also sequential future design and operation decisions. Despite extensive interest in the topic, the state of the art in designing flexibility into aerospace systems, and particularly space systems, tends to be limited to analyses that are qualitative, deterministic, single-objective, and/or limited to consider a single future time period. To address these gaps, this thesis develops a stochastic, multi-objective, and multi-period framework for integrating flexibility into space system design decisions. Central to the framework are five steps. First, system configuration options are identified and costs of switching from one configuration to another are compiled into a cost transition matrix. Second, probabilities that demand on the system will transition from one mission to another are compiled into a mission demand Markov chain. Third, one performance matrix for each design objective is populated to describe how well the identified system configurations perform in each of the identified mission demand environments. The fourth step employs multi-period decision analysis techniques, including Markov decision processes (MDPs) from the field of operations research, to find efficient paths and policies a decision-maker may follow. The final step examines the implications of these paths and policies for the primary goal of informing initial system selection. Overall, this thesis unifies state-centric concepts of flexibility from economics and engineering literature with sequential decision-making techniques from operations research. The end objective of this thesis' framework and its supporting analytic and computational tools is to enable selection of the next-generation space systems today, tailored to decision-maker budget and performance preferences, that will be best able to adapt and perform in a future of changing environments and requirements. Following extensive theoretical development, the framework and its steps are applied to space system planning problems of (1) DARPA-motivated multiple- or distributed-payload satellite selection and (2) NASA human space exploration architecture selection.

本論文觀察台灣年輕人說閩南語的國語口音，建立語料庫作為分析基礎，並根據優選理論中的浮動制約模型（Floating Constraint, Reynolds 1994）分析語料。 本文語料主要分為兩大組：A組及B組。除AB兩組均保留雙唇濁塞聲母 /b/之外，A組的國語口音較明顯，亦即軟顎濁塞聲母 /g/ 較常丟失、齒齦清塞音韻尾 /t/ 較常丟失、雙唇及軟顎清塞音韻尾 /p, k/ 常丟失或發為 /t/。B組的國語口音較不明顯，亦即較常保留上述輔音。 本文針對AB兩組的聲母及韻尾語料數據，各提出一組浮動制約。相較於A組，B組在聲母的浮動制約多了一個信實制約MAX-PLACE、在韻尾部分也多了另一個信實制約MAX-CONSONANT(CODA)。因此B組的信實制約有較多機會浮動至高層，也導致較多信實的輸出值。由此可見，兩組差異之關鍵在於浮動而非固定的制約，因此認為浮動制約模型適合用於處理此種語言變異現象。 / This thesis establishes a corpus of Taiwan youngsters’ Mandarin-accented pronunciation of Taiwanese voiced stop onsets /b/ and /g/ and voiceless stop codas /p, t, k/. The Floating Constraint model (Reynolds 1994) within the Optimality Theory framework is adopted to analyze the corpus data. The corpus includes two groups: Group A and Group B. Both groups retain the voiced bilabial stop onset /b/. Group A has higher percentages of omitting /g/ onset and /t/ coda, and codas /p/ and /k/ are often altered to /t/ or omitted. On the other hand, Group B tends to preserve those sounds. For each group, a set of floating constraints is proposed to account for their onset and coda data. The differences between Group A and Group B lie essentially in the number of floating faithfulness constraints. The Group B grammar allows one more floating constraint MAX-PLACE for onsets, and one more floating constraint MAX-CONSONANT(CODA) for codas. I have shown that the Mandarin accent is better accounted for in terms of the “floating” constraints, but not the “fixed” constraints.

The aim of this work is to make some investigations concerning duality for multiobjective optimization problems. In order to do this we study first the duality for scalar optimization problems by using the conjugacy approach. This allows us to attach three different dual problems to a primal one. We examine the relations between the optimal objective values of the duals and verify, under some appropriate assumptions, the existence of strong duality. Closely related to the strong duality we derive the optimality conditions for each of these three duals. By means of these considerations, we study the duality for two vector optimization problems, namely, a convex multiobjective problem with cone inequality constraints and a special fractional programming problem with linear inequality constraints. To each of these vector problems we associate a scalar primal and study the duality for it. The structure of both scalar duals give us an idea about how to construct a multiobjective dual. The existence of weak and strong duality is also shown. We conclude our investigations by making an analysis over different duality concepts in multiobjective optimization. To a general multiobjective problem with cone inequality constraints we introduce other six different duals for which we prove weak as well as strong duality assertions. Afterwards, we derive some inclusion results for the image sets and, respectively, for the maximal elements sets of the image sets of these problems. Moreover, we show under which conditions they become identical. A general scheme containing the relations between the six multiobjective duals and some other duals mentioned in the literature is derived. / Das Ziel dieser Arbeit ist die Durchführung einiger Untersuchungen bezüglich der Dualität für Mehrzieloptimierungsaufgaben. Zu diesem Zweck wird als erstes mit Hilfe des so genannten konjugierten Verfahrens die Dualität für skalare Optimierungsaufgaben untersucht. Das erlaubt uns zu einer primalen Aufgabe drei unterschiedliche duale Aufgaben zuzuordnen. Wir betrachten die Beziehungen zwischen den optimalen Zielfunktionswerten der drei Dualaufgaben und untersuchen die Existenz der starken Dualität unter naheliegenden Annahmen. Im Zusammenhang mit der starken Dualität leiten wir für jede dieser Dualaufgaben die Optimalitätsbedingungen her. Die obengenannten Ergebnisse werden beim Studium der Dualität für zwei Vektoroptimierungsaufgaben angewandt, und zwar für die konvexe Mehrzieloptimierungsaufgabe mit Kegel-Ungleichungen als Nebenbedingungen und für eine spezielle Quotientenoptimierungsaufgabe mit linearen Ungleichungen als Nebenbedingungen. Wir assoziieren zu jeder dieser vektoriellen Aufgaben eine skalare Aufgabe für welche die Dualität betrachtet wird. Die Formulierung der beiden skalaren Dualaufgaben führt uns zu der Konstruktion der Mehrzieloptimierungsaufgabe. Die Existenz von schwacher und starker Dualität wird bewiesen. Wir schliessen unsere Untersuchungen ab, indem wir eine Analyse von verschiedenen Dualitätskonzepten in der Mehrzieloptimierung durchführen. Zu einer allgemeinen Mehrzieloptimierungsaufgabe mit Kegel-Ungleichungen als Nebenbedingungen werden sechs verschiedene Dualaufgaben eingeführt, für die sowohl schwache als auch starke Dualitätsaussagen gezeigt werden. Danach leiten wir verschiedene Beziehungen zwischen den Bildmengen, bzw., zwischen den Mengen der maximalen Elemente dieser Bildmengen der sechs Dualaufgaben her. Dazu zeigen wir unter welchen Bedingungen werden diese Mengen identisch. Ein allgemeines Schema das die Beziehungen zwischen den sechs dualen Mehrzieloptimierungsaufgaben und andere Dualaufgaben aus der Literatur enthält, wird dargestellt.

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Η παρούσα εργασία διερευνά την αντιληπτικότητα δύο κατηγοριών διμελών συμφωνικών συμπλεγμάτων του τύπου [φρακτικό + φρακτικό] και [φρακτικό + υγρό] σε αρχικές και ενδιάμεσες, τονισμένες ή άτονες συλλαβές λέξεων της ελληνικής από 26 πληροφορητές, φυσικούς και αλλόγλωσσους (με μητρική γλώσσα την αλβανική και βουλγαρική) ομιλητές της ΚΝΕ. Η εκτεταμένη ποικιλία που χαρακτηρίζει τα εμπειρικά δεδομένα συντελεί στην υιοθέτηση της Θεωρίας του Βέλτιστου σε συνδυασμό με το μοντέλο των Πολλαπλών Παράλληλων Γραμματικών. Μετά την ολοκλήρωση της πειραματικής διαδικασίας κατέστη εμφανές ότι το σύστημα της εκάστοτε μητρικής γλώσσας των αλλόγλωσσων ασκεί επιρροή στην επίτευξη του υψηλότερου δυνατού επιπέδου γλωσσομάθειας της ΚΝΕ είτε ως μητρικής - στην περίπτωση των δίγλωσσων ομιλητών - είτε ως δεύτερης / ξένης γλώσσας. / This paper examines the perception of two-member [obstruent + obstruent] and [obstruent + liquid] consonant clusters in word-initial and word-medial, stressed or non stressed syllables in Modern Greek words by 26 informants, native speakers and Albanian and Bulgarian [as L1] speakers of Greek. Due to the extensive variation of the experimental data we use the frame work of Optimality Theory in combination with the model of Multiple Parallel Grammars. At the end of the experimental process it became obvious that the phonological system of L1 influences the acquisition or learning at the highest possible level (that of an adult native speaker) of Greek either as L1 – in the case of bilingual speakers - either as L2, second / foreign language learning.

Αντικείμενο μελέτης της εργασίας είναι η διαχρονία της ανύψωσης φωνηέντων στη Νεότερη Ελληνική. Αρχικά, παρουσιάζεται η ιστορική πορεία του φαινομένου και διατυπώνεται μια πρόταση για τη χρονολόγησή του. Κατόπιν, εξετάζονται συγχρονικά οι όροι εφαρμογής και η γεωγραφική κατανομή του φαινομένου στη Νέα Ελληνική και επιχειρείται μια σύγκριση των ελληνικών δεδομένων με δεδομένα άλλων γλωσσών. Επίσης, υιοθετείται μια ανάλυση στο πλαίσιο της Θεωρίας του Βέλτιστου και συζητώνται τα μειονεκτήματά της. Τέλος, με αφετηρία την ανύψωση φωνηέντων της Ελληνικής, θίγονται ορισμένα θεωρητικά θέματα σε σχέση με τη φωνολογική μεταβολή και τους τρόπους με τους οποίους αυτή εξαπλώνεται. / This study examines the diachrony of vowel raising in Greek. First, it presents the historical evolution of this phenomenon and deals with its dating. Then, it describes the conditioning environment of raising and its geographical distribution in Modern Greek. Moreover, Greek data is compared to relevant cross-linguistic data. An Optimality theoretic analysis is presented and its drawbacks are discussed. Last but not least, it is argued that the Greek phenomenon under scrutiny can contribute to a better understanding of sound change and how it spreads.

Cette thèse est composée de trois essais liés à la conception de mécanisme et aux enchères. Dans le premier essai j'étudie la conception de mécanismes bayésiens efficaces dans des environnements où les fonctions d'utilité des agents dépendent de l'alternative choisie même lorsque ceux-ci ne participent pas au mécanisme. En plus d'une règle d'attribution et d'une règle de paiement le planificateur peut proférer des menaces afin d'inciter les agents à participer au mécanisme et de maximiser son propre surplus; Le planificateur peut présumer du type d'un agent qui ne participe pas. Je prouve que la solution du problème de conception peut être trouvée par un choix max-min des types présumés et des menaces. J'applique ceci à la conception d'une enchère multiple efficace lorsque la possession du bien par un acheteur a des externalités négatives sur les autres acheteurs. Le deuxième essai considère la règle du juste retour employée par l'agence spatiale européenne (ESA). Elle assure à chaque état membre un retour proportionnel à sa contribution, sous forme de contrats attribués à des sociétés venant de cet état. La règle du juste retour est en conflit avec le principe de la libre concurrence puisque des contrats ne sont pas nécessairement attribués aux sociétés qui font les offres les plus basses. Ceci a soulevé des discussions sur l'utilisation de cette règle: les grands états ayant des programmes spatiaux nationaux forts, voient sa stricte utilisation comme un obstacle à la compétitivité et à la rentabilité. Apriori cette règle semble plus coûteuse à l'agence que les enchères traditionnelles. Nous prouvons au contraire qu'une implémentation appropriée de la règle du juste retour peut la rendre moins coûteuse que des enchères traditionnelles de libre concurrence. Nous considérons le cas de l'information complète où les niveaux de technologie des firmes sont de notoriété publique, et le cas de l'information incomplète où les sociétés observent en privée leurs coûts de production. Enfin, dans le troisième essai je dérive un mécanisme optimal d'appel d'offre dans un environnement où un acheteur d'articles hétérogènes fait face a de potentiels fournisseurs de différents groupes, et est contraint de choisir une liste de gagnants qui est compatible avec des quotas assignés aux différents groupes. La règle optimale d'attribution consiste à assigner des niveaux de priorité aux fournisseurs sur la base des coûts individuels qu'ils rapportent au décideur. La manière dont ces niveaux de priorité sont déterminés est subjective mais connue de tous avant le déroulement de l'appel d'offre. Les différents coûts rapportés induisent des scores pour chaque liste potentielle de gagnant. Les articles sont alors achetés à la liste ayant les meilleurs scores, s'il n'est pas plus grand que la valeur de l'acheteur. Je montre également qu'en général il n'est pas optimal d'acheter les articles par des enchères séparées. / This thesis is made of three essays related to mechanism design and auctions. In first essay I study Bayesian efficient mechanism design in environments where agents' utility functions depend on the chosen alternative even if they do not participate to the mechanism. In addition to an allocation rule and a payment rule the designer may choose appropriate threats in order to give agents the incentive to participate and maximize his own expected surplus; The planner may presume the type of an agent who does not participate. I show that the solution of the design problem can be found by a max - min choice of the presumed types and threats. I apply this to the design of an efficient multi-unit auction when a buyer in possession of the good causes negative externalities on other buyers.\\ The second essay considers the fair return rule used by the European Space Agency (ESA). It ensures each member state of ESA a return proportional to its contribution, in the form of contracts awarded to firms coming from that state. The fair return rule is in conflict with the principle of free competition since contracts are not necessarily awarded to firms with the lowest bids. This has raised debates on the use of this rule: it is well accepted by small states, but larger states with strong national space programs, see its strict use as an obstacle to competitiveness and cost effectiveness. It is easy to believe that this rule is more costly to the agency than traditional auctions. We show on the contrary that an adequate implementation of the fair return rule may cause it to be less expensive to the agency than the traditional auctions of free competition. We consider the case of complete information where firms' technology levels are common knowledge, and the case of incomplete information where firms observe privately their production costs. In both cases we show that adequate implementation of the fair return rule may help take advantage of asymmetries between countries in order to expect a lower cost than with traditional auctions.\\ Finally, in the third essay I derive an optimal procurement mechanism in an environment where a buyer of heterogeneous items faces potential suppliers from different groups, and is constrained to choose a winning list that is consistent with some exogenous quotas assigned to the different groups. The optimal allocation rule consists of assigning priority levels to suppliers on the basis of their cost reports. The way these priority levels are determined is subjective but known to all before the auction. The individual reports induce scores for each potential winning list. The items are then purchased from one of the lists with the best score, provided it is not greater than the buyer's valuation for the items. I also find that it is not optimal to purchase the items through separate auctions, unless the buyer's valuation is sufficiently high or low.

在前人的研究中，已透過音韻規則的角度分析梅縣客語 (Meixian Hakka) 和曼谷客語 (Bangkok Hakka)， 但仍有部分疑問未獲得合理解釋。諸如：部分聲調不會受變調規則(Tone sandhi)的影響、變調的觸發條件以及本調 (Citation tone) 和變調間結構上的關係等。 有鑒於此，本研究透過優選理論 (Optimality theory, OT) 重新分析梅縣客語和曼谷客語。 上述兩個方言有兩種變調的方式 : 同化(assimilation)和異化(dissimilation)。在此基礎上，為了更準確的描述變調現象，本研究在分析上主要採用必要性起伏原則 (obligatory contour principle) 和避免起伏原則 (no-jumping principle)，並應用聯合制約 (Constraint Conjunction approach) 的概念。採取此分析方式的理由在於分析對象的變調具有相當有標(marked)且受限於中心詞(head)右端音節的聲調。此外，本研究也採用一部分比聲調結構性制約(tonal markedness constraint)更高排序的信實性制約(faithfulness constraint)。這些制約會導致部分聲調或變調結構不受變調規則影響，例如：調域 (register) 和聲調的起點 (initial target) 將保留原始樣貌。 研究結果指出，聲調結構性制約和數個排序最高的聲調信實性制約能更準確地呈現梅縣客語和曼谷客語在變調時，輸入值與輸出值之間的對應關係 (input-output correspondence)。在論文結尾，筆者將綜覽本研究並提出未來可繼續延伸的相關議題。 / The grammar of Meixian and Bangkok Hakka tone sandhi has been analyzed from a rule based approach. Nevertheless, there are some questions and details that could not be solved by the analysis, such as the status of tones that do not undergo sandhi, triggers of the tone sandhi, and the structural relation between citation tones and their sandhi counterparts. Thus, the purpose of this study is to re-analyze the tone sandhi in Meixian and Bangkok Hakka under the constraint based framework, Optimality Theory (OT). There are two mechanisms of tonal alternations in the two dialects’ tone sandhi: assimilation, and dissimilation. So in order to capture the tonal alternations, the current analysis applies the concepts of the Obligatory Contour Principle, and the No-Jumping Principle. The constraints generated according to these principles work well with the application of the Constraint Conjunction approach. The conjoined constraints are needed since the tone alternations are highly marked, and depend a lot on the head/right syllable tone. Furthermore, this thesis also posits several faithfulness constraints that rank higher than the tone sandhi markedness constraint. The high ranked faithfulness constraints govern the preservation of several tones from any alternation, and preservation of some structures of the citation tones when they become sandhi tones (i.e. register and initial target). In conclusion, the positing of tone sandhi markedness constraints and undominated identity constraints presents a better input-output correspondence relation of the tone sandhi phenomena in Meixian and Bangkok Hakka. To conclude the thesis, a brief summary of the study and possible further issues are presented.

I investigated Lake Sturgeon (Acipenser fulvescens) foraging and anti-predator behaviour. My goals were to understand: (1) The role of environmental change on foraging and anti-predator behaviour trade-offs. (2) The relative cost/benefit trade-off between escape behaviour and cover-seeking behaviour. (3) How development of several independent morphological traits affects anti-predator behaviours. I used simulated river mesocosms to study Lake Sturgeon behavioural ecology under controlled conditions. I found: (1) Foraging intensity was significantly higher during the night than the day as well as in turbid environments versus clear environments, indicating that decreased turbidity alone, may in part drive anti-predator behaviour and constrain foraging activity. (2) In high-risk clear-water environments, Lake Sturgeon responded to danger by evoking an escape response and seeking cover in rocky microhabitats. However, in low-risk turbid environments, Lake Sturgeon responded to danger by seeking cover in rocky microhabitats, but not fleeing to a significant degree. Cover-seeking behaviour may therefore be a relatively low-cost/high-benefit anti-predator strategy. (3) Strong evidence for trait co-dependence between escape responses and body size, where larger fish were able to elicit stronger escape responses. I also found that cover-seeking behaviour exhibited a complex multi-tiered relationship, representing a mixture of trait compensation and trait co-specialization that is dependent on specific combinations of morphological traits. These findings are important because they help us understand: (1) The degree to which anti-predator behaviour can be influenced by changing environmental conditions. (2) The relative cost/benefit trade-off between two common anti-predator behaviours. (3) How behaviour and morphology interact in species with a complex anti-predator phenotype.