• Title/Summary/Keyword: Weak localization

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Gate-voltage controlled Rashba effect in semiconductor

  • 홍진기;이진서;주성중;이긍원;안세영;이제형;김진상;신경호;이병찬
    • Proceedings of the Korean Magnestics Society Conference
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    • 2003.06a
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    • pp.168-169
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    • 2003
  • 최근 세계적 주목을 받고 있는 spin FET 소자는 반도체에 주입된 spin 편향된 전자가 gate voltage(V$_{G}$)에 의해 반도체 계면에 유도된 전기장의 영향을 받아, Spin 세차운동을 하는 mechanism(Rashba 효과)이 근간을 이루고 있다. 작은 band gap을 가지는 반도체(narrow gap 반도체)는 작은 유효질량의 전자에 의해서 이러한 Rashba 효과를 크게 할 수 있어서, spin FET 구현을 위한 강력한 후보이며, 요즘 한창 연구되고 있는 주제이기도 하다. Rashba 효과가 저자기장 영역에서의 weak antilocalization효과로 나타남을 이용하여, 본 논문에서는 metal gate가 형성된 HgCdTe FET를 제작하여(FET1 시료, Fig. 1(a)참조), V$_{G}$에 따른 weak localization(WL) 및 weak antilocalization(WAL) 효과를 얻었다. 또한, Rashba 효과에 의한 spin 세차운동을 측정할 수 있는 소자(FET3 시료, Fig.1(b) 참조)를 제작하여 spin FET 구조에 대하여 연구하였다.

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Grad-CAM based deep learning network for location detection of the main object (주 객체 위치 검출을 위한 Grad-CAM 기반의 딥러닝 네트워크)

  • Kim, Seon-Jin;Lee, Jong-Keun;Kwak, Nae-Jung;Ryu, Sung-Pil;Ahn, Jae-Hyeong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.2
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    • pp.204-211
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    • 2020
  • In this paper, we propose an optimal deep learning network architecture for main object location detection through weak supervised learning. The proposed network adds convolution blocks for improving the localization accuracy of the main object through weakly-supervised learning. The additional deep learning network consists of five additional blocks that add a composite product layer based on VGG-16. And the proposed network was trained by the method of weakly-supervised learning that does not require real location information for objects. In addition, Grad-CAM to compensate for the weakness of GAP in CAM, which is one of weak supervised learning methods, was used. The proposed network was tested through the CUB-200-2011 data set, we could obtain 50.13% in top-1 localization error. Also, the proposed network shows higher accuracy in detecting the main object than the existing method.

Wavelet Transform Based Time-Frequency Domain Reflectometry for Underground Power Cable (지중 전력 케이블에 대한 웨이블릿 변환 기반 시간-주파수 영역 반사파 계측법 개발)

  • Lee, Sin-Ho;Choi, Yoon-Ho;Park, Jin-Bae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.12
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    • pp.2333-2338
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    • 2011
  • In this paper, we develope a wavelet transform based time-frequency domain reflectometry (WTFDR) for the fault localization of underground power cable. The conventional TFDR (CTFDR) is more accurate than other reflectometries to localize the cable fault. However, the CTFDR has some weak points such as long computation time and hard implementation because of the nonlinearity of the Wigner-Ville distribution used in the CTFDR. To solve the problem, we use the complex wavelet transform (CWT) because the CWT has the linearity and the reference signal in the TFDR has a complex form. To confirm the effectiveness and accuracy of the proposed method, the actual experiments are carried out for various fault types of the underground power cable.

Metal-insulator Transition in Low Dimensional $La_{0.75}Sr_{0.25}VO_3$ Thin Films

  • Huynh, Sa Hoang;Dao, Tran M.;Mondal, Partha S.;Takamura, Y.;Arenholz, E.;Lee, Jai-Chan
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.10a
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    • pp.19.1-19.1
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    • 2011
  • We report on the metal-insulator transition that occurs as a function of film thickness in ultrathin $La_{0.75}Sr_{0.25}VO_3$ films. The metal-insulator transition displays a critical thickness of 5 unit cell. Above the critical thickness, metallic films exhibit a temperature driven metal-insulator transition with weak localization behavior. With decreasing film thickness, oxygen octahedron rotation in the films increases, causing enhanced electron-electron correlation. The electron-electron correlations in ultrathin films induce the transition from metal to insulator in addition to Anderson localization.

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SLAM Aided GPS/INS/Vision Navigation System for Helicopter (SLAM 기반 GPS/INS/영상센서를 결합한 헬리콥터 항법시스템의 구성)

  • Kim, Jae-Hyung;Lyou, Joon;Kwak, Hwy-Kuen
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.8
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    • pp.745-751
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    • 2008
  • This paper presents a framework for GPS/INS/Vision based navigation system of helicopters. GPS/INS coupled algorithm has weak points such as GPS blockage and jamming, while the helicopter is a speedy and high dynamical vehicle amenable to lose the GPS signal. In case of the vision sensor, it is not affected by signal jamming and also navigation error is not accumulated. So, we have implemented an GPS/INS/Vision aided navigation system providing the robust localization suitable for helicopters operating in various environments. The core algorithm is the vision based simultaneous localization and mapping (SLAM) technique. For the verification of the SLAM algorithm, we performed flight tests. From the tests, we confirm the developed system is robust enough under the GPS blockage. The system design, software algorithm, and flight test results are described.

A Study on Case for Localization of Korean Enterprises in India (인도 진출 한국기업의 현지화에 관한 사례 연구)

  • Seo, Min-Kyo;Kim, Hee-Jun
    • International Commerce and Information Review
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    • v.16 no.4
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    • pp.409-437
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    • 2014
  • The purpose of this study is to present the specific ways of successful localization by analyzing the success and failures case for localization within the framework of the strategic models through a theoretical background and strategic models of localization. The strategic models of localization are divided by management aspects such as the localization of product and sourcing, the localization of human resources, the localization of marketing, the localization of R&D, harmony with a local community and delegation of authority between headquarters and local subsidiaries. The results, by comparing and analyzing the success and failures case for localization of individual companies operating in India, indicate that in terms of localization of product and sourcing, there are successful companies which procure a components locally and produce a suitable model which local consumers prefer and the failed companies which can not meet local consumers' needs. In case of localization of human resources, most companies recognize the importance of this portion and make use of superior human resource aggressively through a related education. In case of localization of marketing, It is found that the successful companies perform pre-market research & management and build a effective marketing skills & after service network and select local business partner which has a technical skills and carry out a business activities, customer support, complaint handling with their own organization. In terms of localization of R&D, the successful major companies establish and operate R&D center to promote a suitable model for local customers. In part of harmony with a local community, it shows that companies which made a successful localization understand the cultural environment and contribute to the community through CSR. In aspect of delegation of authority between headquarters and local subsidiaries, it is found that most of Korean companies are very weak for this part. there is a tendency to be determined by the head office rather than local subsidiaries. Implication of this thesis is that Korean enterprises in India should carry forward localization of products and components, foster of local human resource who recognize management and system of company and take part in voluntary market strategy decision, wholly owned subsidiary, establishment and operation of R & D center, understanding of local culture and system, corporate social responsibility, autonomy in management.

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MMP-2 and MMP-9 are Differentially Involved in Molar Growth

  • Kim, Min-Seok;Kang, Jee-Hae;Kim, Dong-Hoo;Yoo, Hong-Il;Jung, Na-Ri;Yang, So-Young;Lee, Eun-Ju;Kim, Sun-Hun
    • International Journal of Oral Biology
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    • v.36 no.4
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    • pp.195-201
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    • 2011
  • Matrix metalloproteinases (MMPs) have been implicated in tissue development and re-modeling. Dynamic morphological changes of tooth germs reflect involvement of these enzymes during odontogenesis. The present study was performed to investigate expression and localization of MMP-2 and MMP-9, which have been known to have type IV collagenase activities, in rat tooth germs at different developmental stages. MMP-2 expression was increased gradually in the tooth germs from cap to crown staged germs at both transcription and translation levels. The localization of this molecule was detected in secretory ameloblasts and preameloblasts. The strong immunoreactivities were occasionally seen along the basement membrane between ameloblasts (or preameloblasts) and odontoblasts (preodontoblasts). However, weak reactivity was detected in odontoblasts and reduced enamel epithelium. The level of MMP-9 expression in the tooth germs was higher in cap stage than in crown staged germs at both transcription and translation levels. They were strongly expressed in both ameloblasts and odontoblasts. Even though reduced enamel epithelium after enamel formation and inner enamel epithelium at the cap stage exhibited weak reactivity, strong reactivity was detected in dental follicles and perifollicular tissues surrounding cap staged germs. These results suggested that MMP-2 may involve degradation of the basement membrane during hard tissue formation, whereas MMP-9 might be involved in remodeling of follicular tissues.

A Study on Case for Localization of Korean Enterprise in Indonesia (인도네시아 진출 한국기업의 현지화에 관한 사례 연구)

  • Swo, Min-Kyo;Kim, Hee-Jun
    • International Commerce and Information Review
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    • v.15 no.4
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    • pp.481-508
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    • 2013
  • The purpose of this study is to research the specific ways of successful localization by analyzing the success and failures case for localization through the theoretical background and the strategic models of localization. The strategic models of localization are divided by management aspects such as the localization of production and sourcing, the localization of human resources, the localization of marketing, the localization of R&D, harmonious relationship with the local community and authority transfer between headquarters and local subsidiaries. And the specific measures of the successful localization are proposed within the framework of the strategic models by comparing and analyzing the success and failures case for localization of individual companies operating in Indonesia. The results indicate that there are successful companies which develop a suitable products for the local climate and failed automobile company which is weak for assembly of complete vehicle in terms of localization of production and sourcing. In case of localization of human resources, most companies recognize the importance of this part and endeavor to secure superior human resource through a related education. It is found that most of the companies perform R & D in their native country. In part of a harmonious relationship with the local community, Korean companies should contribute to the community and be friendly with local residents and make a good image of the company focusing on the cultural environment. In aspect of authority transfer between headquarters and local subsidiaries, there is a tendency to be determined by the head office rather than the joint participation. In the future, in order for Korean enterprise to be successful one in Indonesia market, a highly interdependent and complex forms between headquarters and local subsidiaries shall be performed and an active exchange of information and the selection of best talent regardless of nationality shall be promoted.

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Acoustic emission localization in concrete using a wireless air-coupled monitoring system

  • Yunshan Bai;Yuanxue Liu;Guangjian Gao;Shuang Su
    • Smart Structures and Systems
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    • v.32 no.4
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    • pp.195-205
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    • 2023
  • The contact acoustic emission (AE) monitoring system is time-consuming and costly for monitoring concrete structures in large scope, in addition, the great difference in acoustic impedance between air and concrete makes the detection process inconvenient. In this work, we broaden the conventional AE source localization method for concrete to the non-contact (air-coupled) micro-electromechanical system (MEMS) microphones array, which collects the energy-rich leaky Rayleigh waves, instead of the relatively weak P-wave. Finite element method was used for the numerical simulations, it is shown that the propagation velocity of leaky Rayleigh waves traveling along the air-concrete interface agrees with the corresponding theoretical properties of Lamb wave modes in an infinite concrete slab. This structures the basis for implementing a non-contact AE source location approach. Based on the experience gained from numerical studies, experimental studies on the proposed air-coupled AE source location in concrete slabs are carried out. Finally, it is shown that the locating map of AE source can be determined using the proposed system, and the accuracy is sufficient for most field monitoring applications on large plate-like concrete structures, such as tunnel lining and bridge deck.

Localization of Klotho in cisplatin induced acute kidney failure (Cisplatin 유도 급성신부전에서 Klotho 단백질의 발현)

  • Park, So-Ra;Kim, Tae-Won;Kim, Young-Jung;Kim, Hyun-Tae;Ryu, Si-Yun;Jung, Ju-Young
    • Korean Journal of Veterinary Research
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    • v.54 no.4
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    • pp.225-231
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    • 2014
  • Klotho deficiency is an early event in acute kidney injury (AKI) that exacerbates acute kidney damage. The present study explored the expression of Klotho and inflammation related factors in cisplatin-induced AKI. Rats (n = 18) were treated with cisplatin intraperitoneal injection (5 mg/kg) or left untreated as controls (n = 6), then sacrificed at 5 (n = 6) and 10 days (n = 6) treatment. Five days after cisplatin injection, the serum kidney enzymes and kidney cell apoptosis were significantly increased. Moreover, the expression of Klotho was decreased when compared to the control group, especially in the cortex and outer medulla regions. In contrast, inflammation related signals including nuclear factor kappa B, tumor necrosis factor-${\alpha}$, and tumor necrosis factor-like weak inducer of apoptosis were enhanced. However, 10 days after cisplatin injection, Klotho expression was enhanced upon both IHC and Western blot analysis, with slightly recovered renal function and decreased apoptosis. Furthermore, inflammation related signals expression was decreased relative to the 5 days group. Overall, this study confirmed the opposite expression patterns between Klotho and inflammation related signals and their localization in cisplatin-induced AKI kidney.