• 한국전자파학회논문지
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• 제22권4호
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• pp.462-469
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• 2011

본 논문에서는 레일리 분포를 가지는 DFT 행렬 기반의 코드북에 LOS용 코드북을 라이시안 페이딩 채널에서 최소 거리를 최대화하는 조건에 맞게 결합, 새로운 하이브리드 코드북 설계 방법을 제안한다. 제안하는 코드북을 LTE 하향 링크 시스템에 적용, 기존의 DFT 행렬을 이용한 코드북과 제안하는 하이브리드 코드북의 성능을 분석한다. 하이브리드 코드북은 K값이 0.28~0.99인 경우, 가장 우수한 성능을 보이면서 레일리 페이딩 채널 및 LOS 성분이 강해지는 모든 경우에서 우수한 성능을 보인다.

• 한국지구과학회:학술대회논문집
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• 한국지구과학회 2010년도 춘계학술발표회 논문집
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• pp.120-120
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• 2010

두 개의 별로 구성되었을 것이라고 여겨진 공생별은 밝기변화는 궤도운동에 따라 밝기가 변하는 것으로 알려졌다. 분광 관측 자료에는 이러한 궤도 변화 외에도 다양한 요소가 밝기 변화에 관여하는 것이 특성으로 나타난다. 또한 공생별은 밝기가 급격하게 증가하고 혹은 감소하기도 하는데, 이는 폭발에 기인하는 것으로 판단된다. 이러한 변화, 궤도 운동에 따라 기하학적 변화와 폭발 현상을 모두 볼 수 있는 대표적인 공생별이 Z And이다. 우리는 선행연구(MIKOLAJEWSKA & KENYON, 1996)에서 발표한 저분산 분광 자료를 이용하여 위상별로 변하는 상대적 선세기 변화를 조사하였다. MIKOLAJEWSKA & KENYON (1996)의 자료는 저분산 기기로(${\Delta\lambda\sim}3{\AA}$), HeI, HII, [OIII]5007, [NeV]등이 관측되었는데, 이러한 선들의 세기를 광이온 모델을 이용하여 예측한 후, 공생별 가스를 이온화시킨 중심별(WD)의 물리적 특성을 연구하였다. 또한 Hyung & Aller가 2002년 8월 12일 Lick Observatory에서 Hamilton Echelle Spectrograph (HES)를 사용하여 3600초 노출 관측한 고 분산 분광자료(${\Delta\lambda\sim}0.1{\AA}$)도 분석하였다. HES 관측 자료는 공생별의 위상이 $\Phi$=0.22이며, HES자료는 $3470{\AA}-9775{\AA}$에서 HI, HII, HeI, HeII, NII, NIII, OII, [OI], [OII], [OIII] 등이 있었다. 이 선들의 선 윤곽을 IRAF와 StarLink/Dipso를 이용하여 분석하고, 각 성분이 위상($\Phi$=0.22)인 상태에서의 관측자에 대해 어떠한 기하학적인 구조를 가지고 있는지 연구하였다. CLOUDY를 사용하여 광 이온 모형성운을 만들어 화학원소 및 성운가스의 물리적 조건을 연구하였다. Z And의 수소의 수밀도($N_H$)는 $10^{8.5}/cm^3$으로 가정하였다. 중심별 온도는 약 110,000K, 광도는 태양의 2000배로 추정되었다.

• Wind and Structures
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• 제22권6호
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• pp.685-701
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• 2016

Downbursts are of great harm to transmission lines and many towers can even be destroyed. The downburst wind field model by Chen and Letchford was applied, and the wind loads of two typical transmission towers in inland areas and littoral areas were calculated separately. Spatial finite element models of the transmission towers were established by elastic beam and link elements. The wind loads as well as the dead loads of conductors and insulators were simplified and applied on the suspension points by concentrated form. Structural analysis on two typical transmission towers under normal wind and downburst was completed. The bearing characteristics and the failure modes of the transmission towers under downburst were determined. The failure state of tower members can be judged by the calculated stress ratios. It shows that stress states of the tower members were mainly controlled by 45 degree wind load. For the inland areas with low deign wind velocity, though the structural height is not in the highest wind velocity zone of downburst, the wind load under downburst is much higher than that under normal wind. The main members above the transverse separator of the legs will be firstly destroyed. For the littoral areas with high deign wind velocity, the wind load under downburst is lower than under normal wind. Transmission towers are not controlled by the wind loads from downbursts in design process.

• Wind and Structures
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• 제22권6호
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• pp.663-684
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• 2016

Conical vortices generated at the corner regions of large-span flat roofs have been investigated by using the Particle Image Velocimetry (PIV) technique. Mean and instantaneous vector fields for velocity, vorticity, and streamlines were measured at three visual planes and for two different flow angles of $15^{\circ}$. The results indicated that conical vortices occur when the wind is not perpendicular to the front edge. The location of the leading edge corresponding to the negative peak vorticity and maximum turbulent kinetic energy was found at the center of the conical vortex. The wind pressure reaches the maximum near the leading edge roof corner, and a triangle of severe suctions zone appears downstream. The mean pressure in uniform flow is greater than that under turbulent flow condition, while a significant increase in the fluctuating wind pressure occurs in turbulent streams. From its emergence to stability, the shape of the vortex cross-section is nearly elliptical, with increasing area. The angle that forms between the vortex axis and the leading edge is much smaller in turbulent streams. The detailed flow structures and characteristics obtained through FLUENT simulation are in agreement with the experimental results. The three dimensional (3-D) structure of the conical vortices is clearly observed from the comprehensive arrangement of several visual planes, and the inner link was established between the vortex evolution process, vortex core position and pressure distribution.

• 한국시뮬레이션학회논문지
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• 제22권1호
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• pp.41-51
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• 2013

이 논문에서는 EV-DO나 브로드캐스트 멀티캐스트 서비스와 같은 CDMA 셀룰러 표준을 목표로 하는 시스템 수준 시뮬레이터의 설계 방법론을 소개한다. 셀 레이아웃, 모바일 분포, 채널 모델링, 수신 전력 계산, 스케줄링, 패킷 에러 예측, 트래픽 생성 등의 절차를 따라 가면서, 시스템 수준 시뮬레이터의 기본 구조와 시뮬레이션 흐름을 기술하였다. 시뮬레이터를 모델링하기 위해, CDMA 시스템과 EV-DO 방송 시스템의 순방향 링크에서의 패킷 데이터 전송을 고려하였다. 셀룰러 표준을 위한 시스템 수준 시뮬레이터는 상위 수준 언어로 모델링 및 개발 되었고, 용량과 커버리지를 포함한 에어 접속부 성능 지표들을 계산 및 예측하는 데에 이용되었다.

• 한국컴퓨터정보학회논문지
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• 제22권11호
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• pp.169-175
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• 2017

In this paper, we propose the elementary school teacher's training direction for effective SW education. In an effort to better understand the efficient SW training contents and methods for teachers, 200 of elementary teachers had been selected from different places in South Korea. The results showed that 1)it should be operated by focusing on the training of female teachers, especially, strengthening the contents of SW ethics. 2)It will need to actively operate the teacher training program to foster the necessary computational thinking and programing for elementary school teacher who work in big cities. 3)It need to create a training program for expanding the SW studying groups. 4)In order to improve the effectiveness of training courses in the development of in-service training programs, the SW ethics contents need to be coordinated with the link the computational thinking and programing. These results are expected to provide the efficient methods to design the future SW training programs.

• 전력전자학회논문지
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• 제22권6호
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• pp.527-534
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• 2017

This paper proposes a new DC link voltage controller for a single-phase power factor correction (PFC) boost converter. The load current of the PFC boost converter affects the capacitor current, whereas the load current changes the output voltage. However, previous works that compensate output current have failed to consider the relationship between load current and duty. Thus, they also fail to maintain a constant output voltage if the load fluctuates under the conditions of a non-rated input voltage. By considering the duty in the load current compensation, the proposed method improves the load transient response regardless of the input voltage. To demonstrate its effectiveness, the proposed method is compared with other control methods by conducting PSM simulations and experiments under a rapidly changing load.

• Structural Engineering and Mechanics
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• 제22권1호
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• pp.85-105
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• 2006

Control of structural response due to seismic excitation in a manner of coupling adjacent buildings has been actively developed, and most attention focused on those buildings of similar height. However, with the rapid development of some modern cities, multi-story buildings constructed with an auxiliary low-rise podium structure to provide extra functions to the complex become a growing construction scheme. Being inspired by the positively examined coupling control approach for buildings with similar height, this paper aims to provide a comprehensive analytical study on control effectiveness of using friction dampers to link the two buildings with significant height difference to supplement the recent experimental investigation carried out by the writers. The analytical model of a coupled building system is first developed with passive friction dampers being modeled as Coulomb friction. To highlight potential advantage of coupling the main building and podium structure with control devices that provide a lower degree of coupling, the inherent demerit of rigid-coupled configuration is then evaluated. Extensive parametric studies are finally performed. The concerned parameters influencing the design of optimal friction force and control efficiency include variety of earthquake excitation and differences in floor mass, story number as well as number of dampers installed between the two buildings. In general, the feasibility of interaction control approach applied to the complex structure for vibration reduction due to seismic excitation is supported by positive results.

• 패션비즈니스
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• 제22권6호
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• pp.115-130
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• 2018

This study looked at how New Zealand's national brand is expressed in fashion design. In other words, the objective of this study was to offer a research methodology about the process that the conceptual national brand materializes through design. The method used in this research was the review of previous literature and research reports for New Zealand national branding. A direct market survey on the characteristics of fashion brands in each travel destination was conducted from February 2017 to February 2018. New Zealand announced its slogan for the national brand '100% pure New Zealand' in 1999, and in 2003 it announced the slogan 'new thinking New Zealand' with the value of 'newness' and 'innovation'. It also has 'Maori branding'. The study found that the three slogans had a consistent link from keywords to associated visual images. The above results were compared to the reminiscent visual images extracted from the website contents of the fashion brand. Then, using a t-shirt as an item, the t-shirt corresponding to each group was classified, and the design element analyzed. As a result, the four groups showed images of 'New Zealand ecology image', 'ethnic & Kiwiana image', 'nostalgic travel image' and 'pop image'.

• 패션비즈니스
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• 제22권6호
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• pp.25-38
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• 2018

Recently, issues on the environment, which have become key bottlenecks relative to sustainable economic development, have generated common concern. However, relatively scant research has been devoted to consideration of relations between consumers' environmental concern, green fashion advertisement value, and green consumption. In this study, using structural equation modeling (SEM), effects of environmental concern, perceived green fashion advertisement value, and attitude towards green fashion advertisements, on ecological purchases and their interrelationships are investigated. A model is constructed to link aforementioned constructs. Data, was collected through a questionnaire-based online survey (www.sojump.com) of 260 Korean consumers and 260 Chinese consumers. Findings suggest that environmental concern can improve their perception of green advertisement value. One of the findings showed strong positive relationship among green advertisement value, positive attitude, and purchase intention towards green fashion advertisement, while environmental concern negatively influenced their attitude towards green fashion advertisements. It suggests that if companies adopt green advertising strategies, environmentally-conscious consumers are willing to pay more, to purchase green fashion goods in to satisfy their needs. We should put more effort in educating consumers about environmental issues, to raise the level of environmental awareness and satisfy their concerns relative to green fashion goods. Conversely, there is significant positive relationship with the moderating effect of consumers' nationality in all paths, so results above would make significant contributions to green literature, and would also contribute to advertisement strategy implications as well. Especially fashion marketers, an use accurate and fair environmental claims in their advertisements to increase sale and profits.