• Ecology and Resilient Infrastructure
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• 제9권3호
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• pp.183-193
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• 2022

초음파 (ultrasonic) 조사시간 (irradiation time)에 따른 Microcystis aeruginosa (M. aeruginosa)의 성장억제 (growth inhibition) 효과를 대용량 (10 L) 조류 시료를 활용해 다양한 초음파 조사시간 동안 (0.5, 1, 1.5, 2, 2.5, 3 hr) 실험실 규모 (lab-scale) 실험을 진행하였다. Chl-a와 M. aeruginosa 개체수 (cell number) 분석 결과, 초음파 조사 종료 이후 모든 실험군에서 Chl-a와 개체수가 감소되어 조류 성장억제가 관찰되었으며, 초음파 조사시간이 2시간 미만인 실험군 (T_B, T_C, T_D)은 저감 이후 조류의 급격한 재성장 (regrowth)이 관측되었으나, 조사시간이 2시간 이상인 실험군 (T_E, T_F, T_G)은 2시간 미만 조사한 실험군 대비 조류성장억제가 1 - 2일 더 지속되는 것을 확인하였다. 또한, 조류의 개체수가 초기 개체수까지 회복 시간 (recovery time)을 검토한 결과 조사시간 2시간을 기준으로 실험군 T_B (0.5 hr)는 7일, T_C (1 hr)와 T_D (1.5 hr)는 약 20일, T_E, T_F, T_G (≥ 2 hr)는 약 30일이 소요되어 초음파 조사 종료 후 초기 개체수까지의 회복 시간의 차이를 확인하였다. 비성장속도 (𝜇)와 일차분해속도(𝜅)를 도출한 결과, 실험군은 성장억제 기간 동안 초음파 조사시간과 비례하여 높은 일차분해율이 도출되었으며, 조사시간이 2시간 이상인 실험군의 재성장 시 비성장속도 (𝜇)는 2시간 미만인 실험군 대비 비성장속도 (𝜇)가 상대적으로 낮은 것으로 확인되었다. 따라서 정체수역 내 장기적인 (30일) 조류 성장억제를 위해서는 최소한 2시간 이상의 초음파 조사가 필요한 것으로 판단되나, 조류 성장억제를 위한 적정 초음파 조사시간은 정체수역의 규모, 수심, 흐름속도, 조류 농도 등의 다양한 현장조건에 따라 결정돼야 하며, 실제 적용 가능성을 높이기 위한 추가 연구가 필요한 것으로 판단된다. 초음파의 영향으로 인한 M. aeruginosa의 세포 표면 및 내부형질 변화를 관찰한 결과, 조류 세포 표면 및 세포막의 손상이 명확히 관측되었으며, 대조군 대비 실험군의 M. aeruginosa의 기낭 파괴 및 교란이 확인되었다.

• 한국전자파학회논문지
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• 제16권5호
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• pp.541-548
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• 2005

본 논문에서는 모의 실험과 측정을 통해 단면이 직사각형인 터널에서 위성 DMB 상용 주파수 대역인 2.65GHz 신호의 전파전파 특성을 분석하였다. 스펙트럼 분석기와 위성 DMB 말기를 이용하여 직선 터널과 300 m의 곡률 반경을 갖는 곡선 터널에서 수신 전력을 측정하여 경로 손실 특성을 비교 분석하였다. 또한 동일한 환경에 대해 ray-launching 방법을 이용한 모의 실험을 수행하여 경로 손실을 예측하고 측정 결과와 비교 분석하였다. 모의실험을 통한 수신신호의 평균 전력은 측정 결과와 2 dB 이내의 오차를 보였으며 이를 통해 시뮬레이터의 신뢰성을 확인할 수 있었다. 측정 결과를 통해 직선 터널과 곡선 터널의 경로 손실 지수는 3.21, 3.98로 차이가 발생함을 알 수 있었다. 이는 곡선 터널의 경우 직접파는 존재하지 않으며 다수의 벽면 반사로 감쇄되어 수신되는 반사파만이 수신기에 도달하기 때문이다. 모의 실험 결과 또한 직선 터널과 곡선 터널의 경로 손실 지수는 3.2, 3.95로 예측할 수 있었으며 이 값은 측정 결과와 거의 일치함을 확인할 수 있었다.

• 한국IT서비스학회지
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• 제18권5호
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• pp.17-30
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• 2019

With the advent of the Fourth Industrial Revolution, virtual reality, a technology that has recently attracted attention, is emerging as a core technology that will lead the future industry by changing the paradigm of various industries. The development of 3D rendering, computer graphics, and mobile technologies enabled the development of various smart devices and led to the popularization of virtual reality services using them. Recently, with the development of virtual reality-related technology, various devices and contents such as VR-related HMDs are being developed and released. However, since the classification for VR technology has not yet been established, it is difficult to define a range of industries and services to which VR can be applied. Therefore, in this study proposes a service classification system in terms of industries that can apply VR technology and services that can be provided based on the studies on industries and services of VR technology related to the Fourth Industrial Revolution. VR's industrial classification consists of eight industries including entertainment, media, education, medical care, architecture, manufacturing, distribution, tourism and each service is divided into two service categories and composed 16 services. Through the collection and analysis of virtual reality service cases, the service distribution and characteristics of each industry can be analyzed. In addition, we can develop a virtual reality new business model and present a service case for the intersecting areas. This study is expected to be used as a basic research for the activation of virtual reality services in the future.

• 패션비즈니스
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• 제14권3호
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• pp.35-51
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• 2010

This study aims at providing data for establishing a marketing strategy which can enhance the competitiveness of Korea domestic SPA(Specialty Store Retailer of Private Label Apparel) Brands by suggesting countermeasure strategy through the observation and analysis for SPA Brands, under the current circumstance in which the systematic and scholastic discussion for the matter, is lack, despite the diastrophism in fashion industry is prospected according to the rapid growth of Global SPA Brands. For this purpose, the characteristic and current status of Global SPA Brands is examined, and the main cause of growth is analyzed by approaching to their marketing characteristic, in this study. In relation with this situation, this study suggests the provisions as below, which are drawn from the analysis on Global SPA Brands' marketing strategy, so that Korea domestic SPA Brands could achieve successive performance under fierce competition. First, to be a competitive SPA Brands a business should be able to supply products with frequent product turnover by an interval level of one week or so, the existent product planning by seasons, as a business obtains various swift informations on consumers' demand with R&D center foundation. Secondly, SPA Brands should establish a strategy that a business can create high net profit by inventory management which enables lowering inventory ratio remarkably, and a strategy for innovative product supply by small quantity batch production, along with founding a high technological logistics system. Third, SPA Brands should establish a strategy for primary cost reduction by overseas dispersed outsourcing in order to enable diverse product development and rational price setting. Fourth, fashion marketers should establish also a strategy for communication by which brand image can be delivered effectively, by firming the brand identity and by informing product characteristic and customer service totally, with the method of VMD and flagship store. Additionary, fashion marketers also should establish a strategy by developing mobile application which can provide brand image and diverse other fashion related information.

• 한국실내디자인학회논문집
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• 제20권3호
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• pp.249-258
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• 2011

As the elderly population are rapidly growing, the elderly who needs special care and nursing homes for them are also growing. However, many nursing homes were planned without considering the hierarchial space organization such as division of housing unit and nursing unit based on the cognitive and behavioral characteristics of the elderly or accessibility and supportiveness of the staff. This study was to examine the hierarchial characteristics in space organization of nursing homes by using Space Syntax. The subjects were 8 nursing homes in Busan. First, spaces in nursing homes were divided into five areas based on the literature review. Then the hierarchy of space organization for the access layer and layers of living floors was grasped by using G-graph. The access layer has a tree-type hierarchical structure and high visuality. Also, average depth of the space was 5. Then the full integration was analyzed. Mobile area, such as elevator, hallways, or living rooms has a high accessibility and the middle corridor type has commonly been characterized. The nursing stations were analyzed through the control degree and it was low in three nursing homes such as B, C, and G. The low clarity was showed in B, D, and F. The low clarity means that it is relatively difficult to recognize the whole space organization of nursing home. Even though the hierarchy of their living floors was tree-type structure with a high visuality, they has a type of grouping spaces around hallways and spreading, or a ring type.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.110-119
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• 2013

As the technologies such as middle-range resonant WPT (wireless power transfer) advance that utilizes medium and low-frequency magnetic field, the importance of safety of such magnetic field is growing. The research on the effect of electromagnetic field on the human body has been mainly done on the GHz range of mobile phones, or 50~60Hz range of electric power systems. However, there has been relatively few works on the 100kHz~10MHz range used in the resonant wireless power transfer. Since there is a difference in the limiting value of magnetic field between widely used ICNIRP EMF guideline and IEEE C95.1 standard, there can be possible confusion when establishing EMF (Electromagnetic Field) standard on the wireless power transfer device in the future. In this paper, the induced current in the human body, which is the basic restriction of the EMF guideline, is calculated using Quasi-static FDTD method when 3D high-resolution human model is exposed to the 100kHz~10MHz magnetic field. Using this result, the feasibility of the magnetic field reference level in the ICNIRP guideline is analyzed.

• 한국정보통신학회논문지
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• 제20권12호
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• pp.2297-2304
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• 2016

본 연구에서는 스마트매트와 카메라 센서를 이용한 가상현실 체험형 운동게임 시스템 설계 및 구현하였다. 사용자 상반신 운동자세인식을 위해 키넥트 카메라 센서를 활용하고 사용자의 걷기 동작을 정확하게 인식하고 다음 취해야할 걷기 운동 동작에 대한 가이드를 제공하기 위해서 LED 표시가 가능한 스마트 매트를 개발하였다. 이를 통합하고 기능성 게임의 재미요소를 결합하여 실제 운동 상황에서 사용자에게 실시간으로 상호작용 정보를 제공하는 가상현실 체험형 운동게임 통합 시스템을 설계 및 구현하였다. 사용자들이 보다 자립적이고 독립적으로 가정 및 건강증진 관련 기관에서 쉽게 운동하는데 기여하는 체험형 운동게임 시스템으로 활용될 것이다.

• 약학회지
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• 제52권1호
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• pp.7-11
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• 2008

A high performance liquid chromatographic (HPLC) method for the determination of glycyrrhizic acid was developed for the quality control of traditional herbal medicinal preparation Bu-Zhong-Yi-Qi-Tang (BZYQT), which is well-known herbal medicine used as tonic. RP-HPLC analysis was carried out using Capcell pak $C_{18}$ MG column $(5\;{\mu},\;150{\times}4.6\;mm)$ and a mobile phase consisting of acetonitrile and water containing 0.03% phosphoric acid (pH 2.46) at a flow rate of 1.0 ml/min. The optimum wavelength for the detection of the glycyrrhizic acid was found at 250 nm using diode-array UV/VIS detector. The glycyrrhizic acid in BZYQT shows good linearity $(r^2>0.999)$ in the range of $15\;{\mu}g/ml$ to 500 ${\mu}g/ml$. The limit of detection (LOD) was less than 5 ng and R.S.D for intra-day and inter-day reproducibility was less than 7%. The mean recovery of the glycyrrhizic acid was $97.3{\sim}113.0%$. These results suggest that the developed HPLC method is simple and efficient, and could be contributed for the quality control of commercial BZYQT products.

• 융합보안논문지
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• 제12권4호
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• pp.3-8
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• 2012

스마트폰의 최근 보급 확대와 함께 비접촉식 초단거리 무선통신 기술인 NFC(Near Field Communication)기술이 탑재된 모바일 NFC 단말기가 주목을 받고 있다. 본 논문은 모바일 NFC 단말기의 개방형 특성과 다양한 서비스, 통신 기술과의 접목으로 인한 보안 취약성 발생 가능성을 알아보고자 한다. 해커는 악성코드가 포함된 URL을 기록한 NFC 태그를 대중 교통 단말기 근처 숨겨진 장소에 부착한다. 이는 온 오프라인이 결합된 융 복합 하이브리드 성격의 공격시도로서 스마트폰은 NFC 운용모드 중 하나인 Reader/Writer 모드를 통해 악의적으로 부착된 NFC 태그를 인식하여 악성코드에 감염이 된다. 다음으로 단말기 사용자는 NFC 운용모드 중 하나인 Peer-to-Peer 모드 이용으로 불특정 다수에게 무의식적인 악성코드 확산을 돕고, 마침내 지정된 D-day에 모바일 DDoS의 형태로 최종 목표지점을 공격한다는 취약점에 대해서 연구한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.63-71
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• 2004

Recently, a sheet forming process of Mg alloys is highlighted again due to increasing demand for Mg wrought alloys in the applications of casings of mobile electronics and outer-skins of light-weight transportation. Microstructure control is essential for the enhancement of workability and formability of Mg alloy sheets. In this research, AZ31 Mg alloy sheets were prepared by hot rolling process and the rolling condition dependency of the microstructure and texture evolution was studied by employing a conventional rolling mill as well as an asymmetric rolling mill. When rolled through multiple passes with a small reduction per pass, fine-grained and homogeneous microstructure evolved by repetitive dynamic and static recrystallization. With higher rolling temperature, dynamic recrystallization was initiated in lower reduction. However with increasing reduction per pass, deformation was locallized in band-like regions, which provided favorable nucleation sites f3r dynamic recrystallization. Through post annealing process, the microstructures could be transformed to more equiaxed and homogeneous grain structures. Textures of the rolled sheets were characterized by $\{0002\}$ basal plane textures and retained even after post annealing. On the other hand, asymmetrically rolled and subsequently annealed sheets exhibited unique annealing texture, where $\{0002\}$ orientation was rotated to some extent to the rolling direction and its intensity was reduced.