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The diploma thesis is focused on the optical beam propagating in the atmosphere in a wireless communication optical link. The first part of the work explains the atmospheric transmission media with turbulence and its effects on reliability of the optical system. The second part introduces methods for turbulence determination based on a statistical approach to turbulence quantification are introduced. In the third part, method of equivalent temperature gradient is described with the advantage of immediate turbulence evaluation. The output of this thesis is the model of turbulent environment formed by the optical elements. Analysis of turbulent properties and non-reciprocal nature of turbulent channel is processed by a 2D simulator based on the mentioned model and method of equivalent temperature gradient.

Entrées multiples, sorties multiples (MIMO) massif est considéré comme l'une des technologies clés de la prochaine génération de communications sans fil. Afin d'effectuer des algorithmes de formation de faisceau en liaison descendante (DL) avec un grand réseau d'antennes, le plus grand défi est l'acquisition d'informations précises d'état de canal à l'émetteur (CSIT). Pour relever ce défi, le duplex à division temporelle (TDD) est favorable aux systèmes MIMO massif grâce à sa réciprocité de canal de la DL et la liaison montante (UL). Cependant, alors que le canal physique dans l'air est réciproque, les front-ends de radiofréquence (RF) dans les émetteurs-récepteurs ne le sont pas ; par conséquent, la calibration devrait être utilisée dans des systèmes pratiques pour compenser l'asymétrie matérielle RF. Dans cette thèse, nous nous efforçons de transformer le concept MIMO massif en réalité en utilisant la calibration de la réciprocité TDD. Les contributions peuvent être résumées comme suit. Tout d'abord, nous proposons un cadre unifié pour la calibration de la réciprocité, qui généralise diverses méthodes de calibration existant dans la littérature, offrant une vue supérieure sur le problème de calibration ainsi que l'ouverture de nombreuses innovations sur les méthodes de calibration. Deuxièmement, sur la base de cette représentation générale, nous proposons trois nouveaux schémas de calibration : une méthode de calibration rapide basée sur le groupement d'antennes, un schéma de calibration pour l'architecture hybride de formation de faisceau, ainsi qu'un mécanisme de suivi des paramètres de calibration et de surveillance de la santé du système qui permet une détection rapide du changement de paramètre. Troisièmement, nous avons effectué des mesures des paramètres de calibration sur une plate-forme réelle afin de révéler les propriétés matérielles. Quatrièmement, nous étudions, du point de vue du système, avec quelle précision un système MIMO massif TDD devrait être calibré. Enfin, grâce à la calibration de réciprocité TDD, nous avons construit un banc d’essai pour MIMO massif, qui est compatible avec l'évolution à long terme (LTE) basé sur la plate-forme « open source » OpenAirInterface, et peut directement fournir un service Internet à un appareil commercial. Le banc d'essai démontre la faisabilité d'intégrer le MIMO massif dans les normes actuelles du projet de partenariat de troisième génération (3GPP) et son utilisation dans le 5G peut être une évolution à partir des systèmes 4G actuels. / Massive multiple-input multiple-output (MIMO) is considered as one of the key technologies that will enable the next generation of wireless communications. In order to perform downlink (DL) beamforming algorithms with large antenna arrays, the biggest challenge is the acquisition of accurate channel state information at the transmitter (CSIT). To take up this challenge, time division duplex (TDD) is favorable to massive MIMO systems thanks to its channel reciprocity in DL and uplink (UL). However, while the physical channel in the air is reciprocal, the radio-frequency (RF) front-ends in transceivers are not; therefore, calibration should be used in practical systems to compensate the RF hardware asymmetry. In this thesis, we focus on turning massive MIMO concept into reality based on TDD reciprocity calibration. The contributions can be summarized as follows. First, we propose a unified framework for reciprocity calibration, which generalizes various calibration methods existing in literature, providing a higher level view on the calibration problem as well as opening up possibilities of numerous innovations on calibration methods. Second, based on this general representation, we propose three new calibration schemes: a fast calibration method based on antenna grouping, a calibration scheme for hybrid beamforming architecture, as well as a calibration parameter tracking and system health monitoring mechanism which allows fast detection of parameter change. Third, we carried out measurements of calibration parameters on a real platform in order to reveal the hardware properties. Fourth, we study, from a system point of view, how accurately a TDD massive MIMO system should be calibrated. Last but not least, enabled by TDD reciprocity calibration, we build up an open source long term evolution (LTE) compatible massive MIMO testbed based on the OpenAirInterface platform, which can directly provide Internet service to a commercial device. The testbed demonstrates the feasibility of integrating massive MIMO into current 3rd Generation Partnership Project (3GPP) standards and its usage in 5G can be a smooth evolution from current 4G systems.

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京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20660号 / 理博第4325号 / 新制||理||1621(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 友永 雅己, 准教授 足立 幾磨, 准教授 鈴木 樹理 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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This research is aimed at finding the classroom environment indicators that lead young preschoolers, three and four years of age, learn civic efficacy to bring a change in the lives of others a member of the classroom community. The sample comprises of six female preschool teachers at a preschool in a University in Southern America. The data collected from; lesson plans, teachers’ portfolio notes, classroom observations, and semi structured interviews. The qualitative analysis tool, NVivo pro was used to analyze the data. For a clear picture of an obscure contextual phenomenon, charts showing emerging civic efficacy themes are added. Findings reveal that inquiry based, collaboratively orchestrated, and meaningfully engaged classrooms have significant potentials to develop civic efficacy in preschoolers. A systematic, well-thought and wisely planned, children’s life relevant, developmentally challenging activities embedded in social context significantly develop civic efficacy in children. The children hone multiple skills such as; inquiry, research, and problem-solving; collective action, reciprocity, and friendship; responsibility, independence, and community building. The limitations and implications are discussed.

Philosophiae Doctor - PhD / This dissertation explored the degree and distribution of social capital forms-social networks, volunteer associations, generalized trust, particularized trust and norms of reciprocity in rural Ethiopia. It aims to contribute to the academic understanding of social capital formation in Africa. Whereas the extent of literature focused on uncovering difference in the distribution of social capital at macro, meso and micro levels, this dissertation instead unpacks how political and economic conditions in rural Ethiopia shape the extent of the different forms of social capital at different levels. Aresi and Menze are selected for the case-study based on their representation of rural Ethiopia's ecological, language, and ethnicity, historical and religious diversity. A household survey (n = 735) was conducted to uncover the distribution of social capital forms at the individual, regional and aggregate levels. Eight focus group discussions and ten key informant interviews were conducted to unpack why the different forms of social capital unfold the way they do. The qualitative interviews were also used for validating the result of the household survey by uncovering how institutional and structural factors reconstituted and redefined at the local level and translated into social capital formation. The empirical result revealed that social networks and norms of reciprocity are the most important social capital apects in the study areas. At the same time, trust relations and formal networks (volunteer organizations) are the least important aspects of social capital. However, over time, community-organization has become an alternative venue where community members relate and support each other. Thus, network-based and community-based social capital are the principal social capital forms in the study areas. This result is largely inconsistent with the previous studies that have been conducted in developed and democratic countries which have asserted generalized trust and impersonal civic organizations as the major forms of social capital, rather than localized and interpersonal forms of social capital. The fact that different forms of social capital are present in different contexts with different levels of importance shows that forms of social capital do not necessarily articulate together. Moreover, the variation in the relative importance of social capital forms shows that the production of social capital is shaped by the prevailing political and economic conditions. Thus, this dissertation makes the case that it is necessary to distinguish among the different forms of social capital both in theory and practice.

This study was undertaken in an attempt to investigate the impact of family, threatened egotism, and reciprocity on a person’s use of intimate violence. Threatened egotism proposes that aggression is the result of high but unstable self-esteem, which is conceptualized as high self-esteem coupled with high narcissism. Self-report questionnaires were administered to randomly selected cluster samples of 423 college students, 147 males and 276 females. The mean age is approximately 22 with 93% indicating they are White and 7% non-White. While no support was found for threatened egotism, violence witnessed in the family of origin and reciprocity were found to significantly impact intimate violence. Analyses conducted separately for males and females indicate that these factors operate differently based on gender.

This in-depth case study examines perceptions of teacher and learner roles and relationships that were the basis for common understanding in the creation and implementation of the new youth curriculum, Come, Follow Me: Learning Resources for Youth, for The Church of Jesus Christ of Latter-day Saints. The assumptions and beliefs of teachers and learners directly influence each other in their perception of their roles and thus, directly influence the type of teaching and learning they engage in. The curriculum was intentionally designed to help members of the Church teach and learn for conversion. Teachers who understand both their role and that of the learners, can invite this type of learning through their teaching. Reciprocity of roles, living what you teach, and principle-based teaching, all contribute to correct perceptions of roles and relationships. Teacher councils—where participants counsel together, look for the good in each other's teaching, practice, and then reflect— help facilitate a climate where teachers risk and try new things, break out of old paradigms of misperceptions of roles and relationships, and move toward an effective teacher role.