도체, 부도체 및 초전도체의 앤더스 상전이 현상

DoctorThis thesis includes three parts. In the first part, we investigate the Anderson transition in a 3-dimensional correlated electronic system. In chapter 1, we introduce the basic concept of Anderson transition and Hartree-Fock approximation with its justification. Then, we explain the methods to analyze a disordered system such as multifractal analysis and the properties of entanglement entropy. In chapter 2, we study the role of local moments in the metal-insulator transitions (MIT) in the weak localization regime where the disorder strength is below the critical point (W Wc). Here, we consider only the short-ranged Hubbard-type interaction and focus on the properties of insulators to study the existence of a many-body localized state (MBL) in a 3- dimensional system. According to the results, two types of Anderson-type insulators are emergent, the phases of which are separated by their interaction strengths. The insulators exhibit differences in the existence of low-energy mobility edges, temperature dependency, magnetization, and entanglement entropy. In the second part, we study the Anderson transition in 2- dimensional disordered superconductors. In Chapter 4, we discuss the delocalization of in-gap state Bogolibov De Gennes (BdG) quasiparticles in a 2-dimensional superconducting system. We reveal that the delocalization of in-gap state BdG quasiparticles is a novel phase transition that is mediated by fluctuations of pairing amplitude. In the appendix of chapter 4, we introduce the basic concept of the tight-binding model in two dimensions and superconductivity in a dirty system. The site-dependent Hartree-Fock approximation for the repulsive interaction and the magnetic field is reviewed focusing on its technical use. Lastly, the role of repulsive interaction is discussed. In the third part, we investigate the distribution of Kondo temperatures due to disorder. In Ch. 5, we study the competition between the Kondo effect and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. We consider a system that has two Kondo temperatures of two RKKY-coupled magnetic impurities because of different local exchange couplings and the density of states. We found that an initial inequality of the Kondo temperature is enhanced due to the inhomogeneous suppression of the Kondo temperature proportional to the RKKY coupling

GNSS와 Vision System의 최적 융합 분석

본 논문은 GNSS 의 문제점인 위치오차와 실외음영지역을 해소하기 위하여 GNSS와 vision system을 융합한 신뢰성있는 고정밀 측위와 최적의 vision system을 분석하였다. 위치결정을 위해서는 최소 4개 이상의 GNSS로부터 선호를 수신 받아야 한다. 그러나 도심지역에서는 고층건물이나 장애물 또는 반사파에 의해 정확한 위치가 어렵다. 이러한 문제점을 해결하기 위하여 vision system을 이용한다. GNSS를 사용하기 열악한 도심지역의 target object에 정확한 위치 값을 결정해 놓는다.그리고 vision system을 이용해 target object를 인식하고, 인식된 target object를 이용하여 위치오차를 보정해 준다. 이동체는 이동중 vision system을 이용하여 target object를 인식하여 위치 데이터 값을 만들어내고, 위치 계산을 수정하여 안정되고 신뢰성 있는 고정밀 측위를 할 수 있다.2