• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.141-143
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• 2024

Cell-Free 시스템은 각 access point(AP)들이 고정적으로 특정 cell 내에 존재하는 유저(UE)에게 서비스하지 않고 서비스 지역 내에 넓게 분산 배치되어 있어 효율적으로 각 유저들에게 서비스할 수 있는 시스템이다. 그러므로 Cell-Free 시스템에서는 최적의 성능을 갖는 UE-AP association 을 찾는 것이 중요한 요소 중 하나로 여겨진다. 따라서 본 논문에서는 User-Centric 방식을 사용하는 Cell-Free MIMO 시스템에서 물리계층보안을 향상시키는 UE-AP association 기법을 제안한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.38-44
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• 2006

In this paper, a new interference-free Home CDMA-PLC(Code Division Multiple Access-Power Line Communication) system based on the binary ZCD(Zero Correlation Duration) spreading code is proposed as a key solution to overcome the previous problems. Binary ZCD spreading code sets with enlarged family sizes are generated by carrying out a chip-shift operation of the preferred pairs. The properties or the proposed ZCD-PLC systems are effective for MPI(Multi-Path Interference) and MAI (Multiple Access Interference) cancellation in the CDMA-PLC systems. By BER performance simulation, we certified the availability of proposed ZCD-CDMA-PLC system.

• Journal of Magnetics
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• v.18 no.4
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• pp.380-385
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• 2013

We find a metastable vortex state of the perpendicular magnetic anisotropy free layer in spin transfer torque magnetic tunneling junctions by using micromagnetic simulations. The metastable vortex state does not exist in a single layer, and it is only found in the trilayer structure with the perpendicular magnetic anisotropy polarizer layer. It is revealed that the physical origin is the non-uniform stray field from the polarizer layer.

• Journal of Information Management
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• v.36 no.1
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• pp.1-32
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• 2005

The scholarly communication crisis is not a journals crisis, but rather a broader crisis in information communications. It is the loss of access to the scholarly research literature, as the rising cost of STM journal subscriptions far out-strip academic library budgets. Now, the open access as alternatives to traditional journal subscription model are emerging for STM scholarly information. There are basically three forms for OA strategies : Open Access Journals(OAJ), Author Self Archiving(ASA), Academic Institutional Repositories(AIR). This paper describes the current trends and analyses potentially serious limitations and obstacles or various issues of the OA strategies, including the notion of scholarly information as a public good, myths of free access, author pay model, holder of copyright, etc.

• Journal of the Korean Society for information Management
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• v.27 no.4
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• pp.89-107
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• 2010

Open access journal has been one of the major academic information sources for researcherscharacterizing itself as free resource. Recently, as competition among academic information service provides becomes intense, open access journal also needs to enhance its service and expand information service function. This study aims to propose service features for next generation service of open access journals by analyzing service features of leading journal database services. As a result, four service features are suggested such as journal article components and multimedia features, expanded searching features, social service features and mobile information service.

• Journal of Magnetics
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• v.2 no.3
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• pp.96-100
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• 1997

A spin valve structure of NiO(40 nm)/Co(2 nm)/Cu(2.6 nm)/Co(x nm)/Ta(5 nm) has been investigated for the application of magnetic random access memory (MRAM). The spin valve structure exhibited very large difference in the coercivities between pinned and free layers, a relatively high GMR ratio, and a low free layer coercivity. The spin valves were prepared by sputtering and were characterized by dc 4-point probe, and VSM. The spin valves with combined free layer exhibited a maximun GMR ratio of 10.4% with a free layer coercivity of about 82 Oe. The spin valves with a single 10 nm thick a-CoNbZr free layer exhibited a GMR ratio of about 4.3% with a free layer coercivity of about 12 Oe. The GMR ratio of the spin valves increased by addition of Co between Cu and a-CoNbZr. It has been confirmed that the coercivity of free layer can be decreased by increasing the thickness of a-CoNbZr. It has been confirmed that the coercivity of free layer can be decreased by increasing the thickness of a-CoNbZr layer without losing the GMR ratio substantially, which was mainly due to high resistivity of the amorphous "layers".

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.5
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• pp.611-618
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• 1999

An efficient and effective access to needed information becomes an important factor in the modern information society. Many people have developed information retrieval (IR) systems that retrieve needed information from a large amount of data at a given time. However, most freely available IR systems have been developed for English text rather than for Korean text. In this research, we have analyzed the IR system freeWAIS-sf, and localized it with the Korean morphological analyzer, namely HAM. The localized freeWAIS-sf can handle both English text and Korean text simultaneously. We have also modified the weighting scheme of freeWAIS-sf. The experimental result shows that the modified weighting scheme outperforms the original one in terms of retrieval effectiveness.

• Journal of The Korea Institute of Healthcare Architecture
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• v.16 no.4
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• pp.25-32
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• 2010

Despite the growing interest in recreation as one of the ways to maintain physical and mental health in modern society, access to leisure facility is an issue for individuals with disabilities. This paper identifies inaccessible features to propose the ways to promote participation and usage of the leisure facilities for individuals with disabilities. A survey of individuals with disabilities is conducted to determine preferred leisure facilities depending on types of disabilities. The result of this survey is used to evaluate current condition of regulated National leisure facility and forest, which include barrier-free facilities (e.g. interconnecting zones, interior spaces, lavatories and other facilities), signage, approachable information kiosks, emergency egress, and detectable warnings. The common issues (e.g. guiding mechanism, accessible route, safety factors, and barrier-free facilities/services) in various types of recreational facilities (e.g. forest recreational center, spa and hot springs, Amusement Park, ski resort) were identified and analyzed.

• Archives of Reconstructive Microsurgery
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• v.23 no.2
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• pp.45-50
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• 2014

Palmar soft tissue defects are best reconstructed using a replacement flap of proper size with adequate soft tissue stability for mechanical resistance as well as with protective sensation. Reconstructive approaches are dictated by injury mechanism, defect size and location, and the status of the wound bed and tendino-skeletal structure. While uninjured portions of the hand can be used as a source for local flaps, the use of free flaps allows for maximal access for selection of the most ideal replacement tissue for the defect to be restored as close to the initial state as possible. Here, we review the garden variety of free flaps used in reconstruction of palmar soft tissue defects.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.8
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• pp.821-827
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• 2014

Many researches on the usage of shared spectrum have continuously been carried out to solve the recent frequency shortage problem and to use efficiently the spectrum without interference. Also, exponential mobile data growth and the solutions needed to address this challenge are parallel key objectives addressed in many countries. Spectrum policy innovation to meet this challenge is the ASA/LSA (Authorized Shared Access/Licensed Shared Access), which is the best access model to employ the small cell technology to meet this mobile traffic growth. Because 3.5 GHz bands is considered as the ASA/LSA frequency, in this paper, we propose the SAM(Spectrum Access Model) in 3~4 GHz bands to estimate the available ASA/LSA bands and to open more free spectrum. These results are utilized as the data to develop the SAM for the small cell and the open frequency in future.