Formation flying of satellites describes a mission in which a set of satellites arrange their position with respect to one another. In this paper, satellite formation flying guidance and control algorithms are investigated in terms of required velocity increment Delta-v, and tracking error for a Chief/Deputy satellite system. Different control methods covering continuous and impulsive laws are implemented and tested for Low Earth Orbit (LEO). Sliding Mode, Feedback Linearization and Model Predictive Controllers are compared to an Impulsive Feedback Law which tracks the mean orbital element differences. Sliding Mode and Feedback Linearization controllers use the same dynamic model which includes Earth Oblateness perturbations. On the other hand, Model Predictive Control with Multi-Objective Cost Function is based on the Clohessy–Wiltshire equations, which do not account for any perturbation and do not cover the eccentricity of the orbit. The comparison was done for two different missions both including Earth Oblateness effects only. A relative orbit mission, which was based on the Prisma Satellite Mission and a rendezvous mission, was implemented. The reference trajectory for the controllers was generated with Yamanaka and Ankersen’s state transition matrix, while a separate method was used for the Impulsive Law. In both of the missions, it was observed that the implemented Impulsive Law outperformed in terms of Delta-v, 1.2 to 3.5 times smaller than the continuous control approaches, while the continuous controllers had a smaller tracking error, 2 to 8.3 times less, both in terms of root mean square error and maximum error in the steady state. Finally, this study shows that the tracking error and Delta-v has inversely proportional relationship. / Formationsflygning av satelliter innebär att en grupp satelliter flyger tillsammans och anpassar sina relativa lägen i förhållande till varandra. I detta examensarbete studerades regleralgoritmer för formationsflygande satelliter med fokus på bränsleförbrukning och positionsavvikelse genom ”Chief & Deputy”-metoden. Olika reglermetoder har studerats, t.ex. Sliding Mode- och Feedback Linearization-reglering för formationsflygningsfall i låg jordbana med J2-störning samt en Model Predictive-reglering för fall med relativ rörelse baserad på Clohessy-Wiltshire-ekvationerna. Vidare studerades en reglermetod baserad på impulsframdrivning. De fyra reglermetoderna implementerades på två olika rymduppdrag. Först ett uppdrag baserat på Prisma-satelliterna för två satelliter i relativ omloppsbana och sedan ett Rendezvous-uppdrag. Referensbanan för alla reglermetoder, utom för implusmetoden, har tagits fram med hjälp av Yamanakas och Ankersens tillståndsmatris. Resultaten visar att den implementerade impulsmetoden presterar bättre med avseende på bränsleförbrukning, medan de kontinuerliga reglermetoderna producerade mindre relativ positionsavvikelse, både med avseende på kvadratiskt medelvärde och maximalt värde.

Formation planning and control for multi-agent robotic systems enables tasks to be completed more efficiently and robustly compared to using a single agent. Applications are found in fields such as agriculture, mining, autonomousvehicle platooning, surveillance, space exploration, etc. In this paper, a complete framework for formation path planning for holonomic ground robots in an obstacle-rich environment is proposed. The method utilizes the Fast Marching Square (FM2) path planning algorithm, and a formation keeping approach which falls within the Leader-Follower category. Contrary to most related works, the role of leader is dynamically assigned to avoid unnecessary rotation of the formation. Furthermore, the roles of the followers are also dynamically assigned to fit the current geometry of the formation. A flexible spring-damper system prevents inter-robot collisions and helps maintain the formation shape. An obstacle avoidance step at the end of the pipeline keeps the spring forces from driving robots into obstacles. The framework is tested on a formation consisting of three Unitree Go1 quadruped robots, both in the Gazebo simulation environment and in lab experiments. The results are successful and indicate that the method is feasible, although further work is needed to adjust the role assignment for larger formations, combine the framework with Simultaneous Localization and Mapping (SLAM) and provide a more robust handling of dynamic obstacles.

This diploma thesis deals with design of reconection-less electronically reconfigurable filter structures which have single input and single output using unconventional active elements, which have ability to adjust one of their parameter e.g. gain or transconductance. The first part describes basic parameters of frequency filters, the division of filters by frequency transfer response and used circuit elements, their operational modes, the principle of reconnection-less electronically reconfiguration and the circuit design method MUNV. Second part describes all active elements used in the proposal of filters, their properties and the implementation using existing transistor-level models. The third part contains the design of three reconnection-less electronically reconfigurable filters and the simulations results obtained from simulation programs OrCAD Capture and PSpice. The obtained results were compared with theoretical behaviour. This part also contains results of these analyses: sensitivity, parasitic, Monte Carlo and temperature to determine the behaviour in varied cases.

L’objet de cette thèse est d’étudier dans un contexte de financiarisation des marchés de matières premières, certaines stratégies adoptées par les investisseurs et leurs impacts sur la volatilité et le co-mouvement excessif entre les marchés énergétiques et financiers. Pour ce faire, trois études sont proposées. La première fait appel aux modèles à changement de régime (MS-VAR) appliqués sur un ensemble des produits énergétiques et couvre la période 1992-2017. Les résultats obtenus suggèrent qu’en période de forte volatilité, les agents commerciaux (agents de couverture) jouent un rôle crucial dans la découverte des prix du marché du gaz. Cependant, ces agents de couverture affectent le bon fonctionnement des autres marchés (pétrole, essence, fioul) et amplifient leur volatilité. La deuxième étude traite les modèles GARCH ADCC versus GARCH DCC sur un échantillon de 17 pays et sur la période 1997-2016. Cette étude met en avant l’effet asymétrique des chocs pétroliers sur les corrélations conditionnelles des marchés asiatiques et africains, qui s’expliquent notamment par les activités d’arbitrage et les comportements hétérogènes des investisseurs. La troisième étude porte sur les modèles autorégressifs à retards échelonnés (ARDL) et révèle qu’après la crise financière, et au-delà des fondamentaux macro-économiques et financiers, l’indice de la spéculation excessive explique, aussi bien à long terme qu’à court terme, la corrélation entre le marché pétrolier et les marchés financiers de certains pays. Ceci génère un phénomène de co-mouvement excessif, et donc un effet de financiarisation sur ces marchés. Enfin, nous concluons les éléments suivantes : premièrement, en période de forte volatilité, le marché du gaz constitue une valeur refuge pour les investisseurs financiers ; deuxièmement, le comportement de l’investisseur explique l’effet de co-mouvement excessif entre le marché pétrolier et certains marchés financiers ; troisièmement, ce phénomène de co-mouvement excessif limite les avantages de la diversification internationale des portefeuilles notamment au moment des turbulences financières. / The object of this thesis is to study in a context of financialization of commodity markets, some strategies adopted by investors and their impact on volatility and excess co-movement between energy markets and financial markets. To this end, three studies are proposed. The first study uses the approach VAR with Switching Regime (MS-VAR) applied to energy markets during the period 1992-2017. The results suggest that during high volatility period, commercial agents (hedging agents) play a crucial role in the discovery of gas market prices. However, these agents affect the efficiency of other markets (crude oil, gasoline, heating oil) and amplify their volatilities. The second study employs GARCH ADCC versus GARCH DCC models for a sample of 17 countries and covering the period 1997-2016. This study highlights the asymmetric effect of oil shocks on the conditional correlations of the Asian and African markets, which can be explained in particular by the arbitrage activities and the heterogeneous behavior of investors. The third study focuses on Autoregressive Distributed Lag models (ARDL) and reveals that after the financial crisis, and beyond the macroeconomic and financial fundamentals, the index of excessive speculation, explains in long term as well as in short term, the correlation between oil market and some financial markets. This generates a phenomenon of excess co-movement, and therefore a financializing effect on these markets. Finally, we can conclude that : firstly, during high volatility period, gas market is a safe haven for financial investors ; secondly, the behavior of the investor explains the effect of excess co-movement between the oil market and some financial markets ; thirdly, this phenomenon of excess co-movement limits the benefits of international portfolio diversification especially during financial turbulences.

<p>This master thesis describes a design exploration of a circuit capable of measuring high speed signals without adding significant capacitive load to the measuring node. </p><p>It is designed in a 0.13 CMOS process with a supply voltage of 1.2 Volt. The circuit is a master and slave, track-and-hold architecture incorporated with a capacitive voltage divider and a NMOS source follower as input buffer to protect the measuring node and increase the input voltage range. </p><p>This thesis presents the implementation process and the theory needed to understand the design decisions and consideration throughout the design. The results are based on transistor level simulations performed in Cadence Spectre. </p><p>The results show that it is possible to observe the analog behaviour of a high speed signal by down converting it to a lower frequency that can be brought off-chip. The trade off between capacitive load added to the measuring node and input bandwidth of the measurment circuit is also presented.</p>

This master thesis describes a design exploration of a circuit capable of measuring high speed signals without adding significant capacitive load to the measuring node. It is designed in a 0.13 CMOS process with a supply voltage of 1.2 Volt. The circuit is a master and slave, track-and-hold architecture incorporated with a capacitive voltage divider and a NMOS source follower as input buffer to protect the measuring node and increase the input voltage range. This thesis presents the implementation process and the theory needed to understand the design decisions and consideration throughout the design. The results are based on transistor level simulations performed in Cadence Spectre. The results show that it is possible to observe the analog behaviour of a high speed signal by down converting it to a lower frequency that can be brought off-chip. The trade off between capacitive load added to the measuring node and input bandwidth of the measurment circuit is also presented.

The performance of analog integrated circuits is dependent on the technology. Digital circuits are scalable in nature, and the same circuit can be scaled from one technology to another with improved performance. But, in analog integrated circuits, the circuit components must be re-designed to maintain the desired performance across different technologies. Moreover, in the case of digital circuits, minimum feature-size (short channel length) devices can be used for better performance, but analog circuits are still being designed using channel lengths larger than the minimum feature sizes. The research in this thesis is aimed at understanding the impact of technology scaling and short channel length devices on the performance of analog integrated circuits. The operational amplifier (op amp) is chosen as an example circuit for investigation. The performance of the conventional op amps are studied across different technologies for short channel lengths, and techniques to develop technology-independent op amp architectures have been proposed. In this research, three op amp architectures have been developed whose performance is relatively independent of the technology and the channel length. They are made scalable, and the same op amp circuits are scaled from a 0.25 um CMOS onto a 0.18 um CMOS technology with the same components. They are designed to achieve large small-signal gain, constant unity gain-bandwidth frequency and constant phase margin. They are also designed with short channel length transistors. Current feedback, gm-boosted, CMOS source followers are also developed, and they are used in the buffered versions of these op amps.

The functionality provided by mobile devices such as cellular phones and tablets continues to increase over the years, with integration of an ever larger number of wireless standards within a given device. In several of these designs, each standard supported by a device requires its own IC receiver to be mounted on the device’s PCB. In multistandard and multimode radios, it is desirable to integrate all receivers onto the same IC as the digital processors for the standards, in order to reduce device cost and size. Ideally all the receivers should also share a single signal chain. Since each standard has its own requirements for linearity and noise figure, and each standard operates at a different RF carrier frequency, implementing such a receiver is very challenging. Such a receiver could be theoretically implemented using a broadband mixing receiver or by direct sampling by a high-speed analog-to-digital converter (ADC). Broadband mixing requires the use of a harmonic rejection mixer (HRM) or tunable band pass filter to remove harmonic mixing effects, which in the past have suffered from a large primary clock tuning range and high power consumption. However, direct sampling of the RF input requires a high-speed ADC with large dynamic range which is typically limited by clock timing skew, clock jitter, or harmonic folding. In this dissertation, techniques for programmable broadband radio receivers are proposed. A local oscillator (LO) synthesis method within HRMs is proposed which reduces the required primary clock tuning range in broadband receivers. The LO synthesis method is implemented in 130-nm CMOS. A clocking technique is introduced within the two-stage HRM, which helps in achieving state-of-the-art harmonic rejection performance without calibration or harmonic filtering. An analog frequency synthesis based broadband channelizer is proposed using the LO synthesis method which is capable of channelizing a broadband input using a single mixing stage and primary clock frequency. A frequency-folded ADC architecture is proposed which enables high-speed sampling with high dynamic range. A receiver based on the frequency-folded ADC architecture is implemented in 65-nm CMOS and achieves a sample rate of 2-GS/s, a mean 49-dB SNDR, and 8.5-dB NF. / text

科学研究費補助金 研究種目:基盤研究(B) 課題番号:17360245 研究代表者:中村 英樹 研究期間:2005-2007年度

台灣IC設計產業的技術並非是最尖端的，也不具有低人力成本與低價格的優勢，並且夾擠在先進的「創新領導型聚落」（例如：美國矽谷）與低成本優勢的「製造成本控制型聚落」（例如：中國大陸上海）之間發展。但台灣新竹的IC設計產業聚落卻仍能在知識快速流動的空間趨勢中，持續且擴大地理群聚效應，成為全球IC/半導體產業的重要節點。因此，本論文旨在回答以下的研究問題：在知識快速流動的空間趨勢中，為什麼台灣IC設計產業仍鑲嵌在台灣的經濟社會環境中持續群聚與成長？ 本論文有以下主要研究結論：（一）IC設計廠商在台灣形成新竹與台北兩個產業聚落，新竹產業聚落包含「快速跟隨型」與「專業化型」兩種台灣IC設計廠商，台北則是「專業化型」廠商群聚。「快速跟隨型」IC設計廠商採取「次進市場」時間策略，「專業化型」IC設計廠商則以「市場區隔」時間策略切入產品生命週期；（二）新竹地區廠商的快速跟隨策略，由速度、彈性與成本控制的制度環境所支撐，其群聚效應與成長速度高於台北產業聚落；（三）本論文驗證了知識的快速流動空間，有助於地方空間的快速技術學習與產業群聚效應。 / Taiwan’s IC design industry, located mainly in the Taipei-Hsinchu corridor, has important status in the global value chain of the world semiconductor industry. Nevertheless, it neither has cutting edge technology nor has the lowest cost advantage; it is besieged between leading innovative cluster (eg. Silicon Valley) and catch-up cluster that is based on production cost (eg. Shanghai). Most significantly, it still continues to grow in the age in which place is said to be meaningless due to the tendency of space of flows. This study thus aims to answer the following question: why does IC design industry still continue to embed in and to grow in the northern part of Taiwan? My research findings can be summarized as follows. First of all, it is found that there are two major IC design clusters in the northern part of Taiwan: Hsinchu and Taipei. Secondly, it is found that firms in Hsinchu cluster have both “fast follower” and “specialist” characteristics, whereas IC design firms in Taipei has only “specialist” features. Fast follower firms adopt “second-to-market” strategy and specialist firms adopt “market-segmentation” strategy to enter the product market in the product-life-cycle. Thirdly, due to the fact that fast follower firms in Hsinchu are supported by institutionalized features that can sustain speed, flexibility, and cost-control which Taipei lacks, Hsinchu thus has better agglomeration effect and growth rate. Finally, this study concludes that current tendency of space of flows in which knowledge can be transmitted through space is contributive to Taiwan’s fast technological learning and clustering effect.