• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.285-297
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• 2015

In this paper, Ulta-WideBand (UWB) channel measurement and modeling based on compressive sampling (CS) are proposed. The sparsity of the channel impulse response (CIR) of the UWB signal in frequency domain enables the proposed channel measurement to have a low-complexity and to provide a comparable performance compared with the existing approaches especially used for the indoor geo-localization purpose. Furthermore, to improve the performance under noisy situation, the soft thresholding method is also investigated in solving the optimization problem for signal recovery of CS. Via numerical results, the proposed channel measurement and modeling are evaluated with the real measured data in terms of location estimation error, bandwidth, and compression ratio for indoor geo-localization using UWB system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.114-130
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• 2022

The purpose of this study was to investigate the possibility of increasing the efficiency of disaster relief rescue operations through collaboration among multiple aerial and ground robots. The robots create 2.5D maps, which are merged into a 2.5D map. The 2.5D map can be handled by a low-specification controller of an aerial robot and is suitable for ground robot navigation. For localization of the aerial robot, a six-degree-of-freedom pose recognition method using VIO was applied. To build a 2.5D map, an image conversion technique was employed. In addition, to merge 2.5D maps, an image similarity calculation technique based on the features on a wall was used. Localization and navigation were performed using a ground robot to evaluate the reliability of the 2.5D map. As a result, it was possible to estimate the location with an average and standard error of less than 0.3 m for the place where the 2.5D map was normally built, and there were only four collisions for the obstacle with the smallest volume. Based on the 2.5D map building and map merging system for the aerial robot used in this study, it is expected that disaster response work efficiency can be improved by combining the advantages of heterogeneous robots.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1120-1131
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• 2011

Researches using time reversal acoustics(TRA) for impact localization have been paid attention to recently. Dispersion characteristics of Lamb waves, which restrict the utility of classical nondestructive evaluation based on time-of-flight information, can be compensated through the application of TRA to Lamb waves on a plate. This study investigates the spatial focusing performance of time reversal Lamb waves on a plate using finite element analysis. In particular, the virtual sensor effect caused by multiple wave reflections at the boundaries of a plate is shown to enable the spatial focusing of Lamb waves though a very small number of surface-bonded piezoelectric(PZT) sensors are available. The time window size of forward response signals, are normalized with respect to the number of virtual active sensors. Then their effects on the spatial focusing performance of Lamb waves are investigated.

• Smart Structures and Systems
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• v.3 no.1
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• pp.23-49
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• 2007

Wavelet transforms are the emerging signal-processing tools for damage identification and time-frequency localization. A small perturbation in a static or dynamic displacement profile could be captured using multi-resolution technique of wavelet analysis. The paper presents the wavelet analysis of damaged linear structural elements using DB4 or BIOR6.8 family of wavelets. Starting with a localized reduction of EI at the mid-span of a simply supported beam, damage modeling is done for a typical steel and reinforced concrete beam element. Rotation and curvature mode shapes are found to be the improved indicators of damage and when these are coupled with wavelet analysis, a clear picture of damage singularity emerges. In the steel beam, the damage is modeled as a rotational spring and for an RC section, moment curvature relationship is used to compute the effective EI. Wavelet analysis is performed for these damage models for displacement, rotation and curvature mode shapes as well as static deformation profiles. It is shown that all the damage indicators like displacement, slope and curvature are magnified under higher modes. A localization scheme with arbitrary location of curvature nodes within a pseudo span is developed for steady state dynamic loads, such that curvature response and damages are maximized and the scheme is numerically tested and proved.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.12-19
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• 1994

KEM1 is known to control the spindle pole body or microtubule function, probably in response to the cellular nutritional conditions in Saccharomyces cerevisiae. Transposon insertions were performed in the cloned KEM1 gene using mini-Tn10-LUK element carrying E. coli ${\beta}$-galactosidase structural gene. A collection of ranfom Tn10-LUK insertions defined an approximately 3.5 kb region required for the KEM1 function. From this collection functional KEM1::lacZ protein fusions were identified. Indirect immunofluorescence using anti-${\beta}$-galacatosidase antibodies localized the KEM1::lacZ fusion protein to the periphery of the nucleus.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.02a
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• pp.139-142
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• 2008

헤드폰 또는 이어폰으로 오디오 청취 시 흔히 음상이 머리 내부에 맺히는 현상이 발생하게 되며, 이러한 현상을 음상 내재화(Inside Head Localization; IHL)라 한다. 오디오의 음상이 머리 주변 혹은 머리 내부에 맺히게 되면 공간감이나 입체감이 떨어지게 되어 음향의 현실감을 저하시키게 되며 또한 청취에 따른 피로도가 증가하게 된다. 이러한 음상 내재화 현상을 제거하여, 헤드폰/이어폰을 통해 오디오 청취 시 음상이 머리의 외부에 맺히도록(Out of Head Localization; OHL) 하는 기술을 음상 외재화(Sound Externalization) 기술이라 한다. 룸 임펄스 응답이 방향 큐와 연계하여 생성되었을 경우 외재화가 가능하다는 실험적 사실을 바탕으로 기존의 음상 외재화 방법은 일반적인 HRTF (Head Related Transfer Function)를 이용하여 외재화 필터를 구성해왔다. 본 논문에서는 구체마이크로폰을 이용하여 녹음한 멀티채널 룸 임펄스 응답을 기반으로 모델링 된 외재화 필터를 이용한 음원 외재화 방법을 제안한다. 또한 실험 및 결과 분석을 통하여 본 알고리즘의 전방 음원 외재화 성능의 우수성을 입증하고, 외재화 알고리즘 적용 후의원 신호 음상 보존 성능을 확인한다.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.195-214
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• 2016

Monitoring of impact loads is a very important technique in the field of structural health monitoring (SHM). However, in most cases it is not possible to measure impact events directly, so they need to be reconstructed. Impact load reconstruction refers to the problem of estimating an input to a dynamic system when the system output and the impulse response function are usually known. Generally this leads to a so called ill-posed inverse problem. It is reasonable to use prior knowledge of the force in order to develop more suitable reconstruction strategies and to increase accuracy. An impact event is characterized by a short time duration and a spatial concentration. Moreover the force time history of an impact has a specific shape, which also can be taken into account. In this contribution these properties of the external force are employed to create a sample-force-dictionary and thus to transform the ill-posed problem into a sparse recovery task. The sparse solution is acquired by solving a minimization problem known as basis pursuit denoising (BPDN). The reconstruction approach shown here is capable to estimate simultaneously the magnitude of the impact and the impact location, with a minimum number of accelerometers. The possibility of reconstructing the impact based on a noisy output signal is first demonstrated with simulated measurements of a simple beam structure. Then an experimental investigation of a real beam is performed.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.176-181
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• 2005

To study calmodulin (CaM) gene expression and its regulation, rice CaM promoter (RCaM-2) was isolated and fused to $\beta-glucuronidase$ (GUS), reporter gene. X-Glue staining patterns revealed that GUS localization is high in meristemic tissues such as the stem apex, stolen tip, and vascular regions. GUS staining in the transverse sections of stem and petiole was restricted to the inside of the vascular system, and cortex and epidermis located outside of the vascular system usually did not show GUS staining even a plant that expressed strong activity. GUS activity was found to be tissue specific expressed and exhibited a dramatic transient increase in response to wounding. These results suggest that the 5'-flanking region of RCaM gene regulates wound-inducible expression.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.72
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• pp.161-183
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• 2016

This study looked at the Korea enterprise in China market practices and strategies in accordance with the Korea China FTA macroscopically. And the systematic localization in the mid-to long-term decisions necessary for successful, it is important to the local economy by contributing to strategic social contribution activities also ensure the reliability of consumers. In addition to factors that may enjoy various benefits from an Korea China FTA strategy it is also needed to maximize the additional benefits of the FTA signed by Korea before. In particular, this strategy requires that the biggest benefits of FTA, that determine the tariff cuts by FTA partners to take advantage of it. In addition, the strategy that should be taken in advance to prevent any unnecessary risks through the recent rapid and thorough understanding of the appropriate response, Chinese, Chinese culture on O2O retail market. It is considered that the Korea China FTA requires multidimensional efforts with seeking a comprehensive and affordable countermeasures in order to act as an important factor for Korea market companies, government, companies and academia at the same time. In particular, the idea to carefully look at the various features with the Chinese consumer market will be a very important point.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.23-28
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• 2004

Antigenic analysis of Herpes simplex type 2 virus was performed and its major antigen was localized using an immunoelectron microscopy. Antigens of 32, 43, 59 and 69 kDa were constantly expressed during the course of infection for 48 hr in the infected Vero cell. An antigen of 51 kDa was turned out to be the major one in inducing a immune response in Western-blot analysis. The 51 kDa antigen was localized on the surface of HSV-2 by immunoelectron microscopy using colloidal golds and anti-HSV 2 polyc1onal antibody. Immunofluorescence assay indicated that viral antigens were found throughout the infected cell and, especially, on the surface of the cell.