Cold ions of ionospheric origin observed at the dayside magnetopause and their effects on magnetic reconnection

Thesis (Ph.D.) University of Alaska Fairbanks, 2015Magnetic reconnection at the dayside magnetopause is one of the most important mechanisms that efficiently transfers solar wind particles, momentum, and energy into the magnetosphere. Magnetic reconnection at the magnetopause is usually asymmetric since the plasma and magnetic field properties are quite different in the magnetosphere and the magnetosheath. Cold dense plasma, originating either directly from the ionosphere or from the plasmasphere, has often been observed at the adjacent magnetopause. These cold plasmas may affect reconnection since they modify the plasma properties on the magnetospheric side significantly. This dissertation presents case and statistical studies of the characteristics of the cold ions observed at the dayside magnetopause by using Cluster spacecraft datasets. The plasmaspheric plumes have been distinguished from the ionospheric outows using ion pitch angle distributions. The ionospheric outows feature unidirectional or bidirectional field-aligned pitch angle distributions, whereas the plasmaspheric plumes are characterized by 90° pitch angle distributions. The occurrence rates of the plasmaspheric plumes and ionospheric outows and their dependence on the solar wind/Interplanetary Magnetic Field (IMF) conditions have been investigated. It is found that the occurrence rate of plasmaspheric plume or ionospheric plasma strongly depends on the solar wind/IMF conditions. In particular, plasmaspheric plumes tend to occur during southward IMF while ionospheric outows tends to occur during northward IMF. The occurrence rate of the plasmaspheric plumes is significantly higher on the duskside than that on the dawnside, indicating that the plasmaspheric plumes may lead to a dawn-dusk asymmetry of dayside reconnection. Furthermore, this dissertation investigates the behavior of the cold dense plasma of ionospheric origin during magnetic reconnection at the dayside magnetopause. The motion of cold plasmaspheric ions entering the reconnection region differs from that of warmer magnetosheath and magnetospheric ions. In contrast to the warmer ions, which are probably accelerated by reconnection near the subsolar magnetopause, the colder ions are simply entrained by E x B drift at high latitudes on the recently reconnected magnetic field lines. This indicates that plasmaspheric ions can sometimes play a very limited role in magnetic reconnection process. Finally, this dissertation examines a controlling factor that leads to the asymmetric reconnection geometry at the magnetopause. It is demonstrated that the separatrix and ow boundary angles are greater on the magnetosheath side than on the magnetospheric side of the magnetopause, probably due to the stronger density asymmetry rather than magnetic field asymmetry at this boundary

Chemometrics approach for species identification of pinus densiflora Sieb. et Zucc. and Pinus densiflora for. erecta Uyeki: -Species classification using near-infrared spectroscopy in combination with multivariate analysis

A model was designed to identify wood species between Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc. using the near-infrared (NIR) spectroscopy in combination with principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). In the PCA using all of the spectra, Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc. could not be classified. In the PCA using the spectrum that has been measured in sapwood, however, Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc. could be identified. In particular, it was clearly classified by sapwood in radial section. And more, these two species could be perfectly identified using PLS-DA prediction model. The best performance in species identification was obtained when the second derivative spectra was used; the prediction accuracy was 100%. For prediction model, the Rp 2 value was 0.86 and the RMSEP was 0.38 in second derivative spectra. It was verified that the model designed by NIR spectroscopy with PLS-DA is suitable for species identification between Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc

일군의 동적 논홀로노믹 기계시스템의 수동성기반 적응 및 강건 안정화 제어기법 연구

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2016. 8. 이동준.We present novel passivity-based stabilization control frameworks for a class of nonholonomic mechanical systems with uncertain inertial parameters. Passive configuration decomposition is first applied to configuration-level decompose the system's Lagrange-DAlembert dynamics into two separate systems. Each of these decomposed systems evolves on its respective configuration space and individually inherits Lagrangian structure and passivity from the original dynamics. Utilizing the nonlinearity and passivity of the decomposed dynamics, we then derive adaptive passivity-based time-varying control (APBVC) and robust passivity-based switching control (RPBSC) schemes, which adopt the concepts of adaptive control and sliding-mode control respectively to achieve stabilization for this certain class of nonholonomic mechanical systems. Both simulation and experimental results are provided to verify our proposed control frameworks.Chapter 1 Introduction 1 1.1 Motivation and Objectives 1 1.2 State of the Art 3 1.3 Contribution of this Work 4 Chapter 2 System Description 6 2.1 Nonholonomic Mechanical Systems with Symmetry Structure 6 2.2 Passive Configuration Decomposition 8 2.3 Control Objective 13 Chapter 3 Passivity-Based Time-Varying Control 16 3.1 Nominal Passivity-Based Time-Varying Control 16 3.2 Adaptive Passivity-Based Time-Varying Control 19 Chapter 4 Passivity-Based Switching Control 25 4.1 Nominal Passivity-Based Switching Control 25 4.2 Robust Passivity-Based Switching Control 29 Chapter 5 Simulation and Experiment 38 5.1 Simulation 38 5.2 Experiment 62 Chapter 6 Conclusion and Future Work 82 6.1 Conclusion 82 6.2 Future Work 83 Bibliography 85 요약 92Maste

Research on Linked Data and Co-reference Resolution

This project report details work carried out in collaboration between the University of Southampton and the Korea Institute of Science and Technology Information, focussing on an RDF dataset of academic authors and publications. Activities included the conversion of the dataset to produce Linked Data, the identification of co-references in and between datasets, and the development of an ontology mapping service to facilitate the integration of the dataset with an existing Semantic Web application, RKBExplorer.com

ニホンゴ キョウシツ ニ オケル ガクセイ ノ ジコ カイジ ノ ケイコウ ニ ツイテ JSDQ ト キョウシツナイ ジハツテキ ハツゲン ニ チュウモク シテ

최근에는 수업 내에서의 학생의 주체성이 중요시되고, 인간 중심（humanistic）의 교 육이 주목받으며, 학생 스스로가 제 2 언어로 자기표현을 하는 것이, 언어 습득 외에도 학 습자의 인간적인 성장으로 이어지는 등, 교육방법으로써 기대를 받게 되었다. 본 연구에 서는, 자기표현 중에서도 ‘ 자기개시（자기공개）’ 에 주목하여, 한 국립대학의 일본어 교 실의 유학생들을 대상으로 교실 내에서의 자기개시의 경향 및 자기개시의 특징을 분석하 고자 하였다. 연구과제는, 1）자기개시의 정도는, 자기개시 내용에 따라 차이가 나타나는가 ? 2）자 기개시의 정도는, 어떤 상대에게 자기개시를 하는가에 따라 변화하는가 ? 3）발언 수와 자기개시의 정도에는 상관관계가 있는가 ? 이다. 본 연구는, 한 학기（2021 년 4 월 14 일 ~2021 년 7 월 28 일）동안 해당 강의를 수강한 유학생 7 명（스페인 3 명, 한국 2 명, 독일 1 명, 프랑스 1 명）을 대상으로 수업에서의 참 여관찰과 자기개시에 대한 질문지（JSDQ-40）조사 및 인터뷰 조사（5 명）를 실시하였다. 연구 결과,（1）자신에게 부정적 영향을 끼칠 가능성이 있는 일에 대해서는 자기개시 를 하지 않으려는 경향이 보였다.（2）상대와의 심리적 거리가 가까울수록 자기 개시의 양과 정도가 깊어지는 경향이 보임으로써, 자기개시가 상대방과의 친밀한 관계를 제고한 다는 점이 시사되었다.（3）JSDQ 의 몇몇의 항목에 대해서는, 학생들의 자기개시 정도 에 큰 개인차가 나타났다.（4）발언 수와 자기개시의 정도에 명확한 상관관계가 보이지 않았다. 향후 연구에서는, 1. 자신의 이데올로기나 상호주관성（inter-subjectivity）등에 대해 깊이 고찰하고, 2. 자기개시 정도의 변화를 시간의 흐름에 따라 관찰할 필요가 있다. 이를 바탕으로, 3. 자기개시가 여러 가지 영향을 받아 변화하는 유기적인 것임을 알고, 연구를 심화하고자 한다