• Journal of the Optical Society of Korea
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• 제12권4호
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• pp.232-239
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• 2008

We investigated how the polarization-mode dispersion (PMD) tolerance was degraded by semiconductor optical amplifier (SOA)-induced chirp for the 10 Gb/s nonreturn-to-zero (NRZ), duobinary NRZ, return-to-zero (RZ), and carrier-suppressed RZ (CS-RZ) modulation formats. The power penalty was calculated as a measure of the system performance due to PMD for a given SOA-induced chirp. Considering only first-order PMD, all modulation formats have a similar PMD tolerance regardless of SOA-induced chirp. On the other hand, when both first- and second-order PMD are considered, the PMD tolerance of all modulation formats with the exception of the CS-RZ modulation format are degraded by SOA-induced chirp. Among all modulation formats considered here, the NRZ modulation format has the PMD tolerance with the highest sensitivity to SOA-induced chirp. When the peak-to-peak chirp induced by SOAs is $0.28{\AA}$, its PMD tolerance is degraded up to 4 dB for a differential group delay (DGD) of 50 ps. However, the PMD tolerance of the CS-RZ modulation format is largely unaffected by SOA-induced chirp.

• 벤처창업연구
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• 제12권5호
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• pp.141-162
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• 2017

IMF 외환위기 이후 기업의 주기적인 구조조정과 최근 경기 불황의 지속에 따른 명예퇴직, 조기퇴직이 증가하고, 고용 없는 경제성장으로 기업의 신규채용이 증가하지 않는다. 본 연구는 이러한 창업시장이 확대되는 사회적, 경제적 환경과 프랜차이즈 산업의 장 단점 및 산업환경에 따른 기회와 위기에 주목하여 외식프랜차이즈를 중심으로 SWOT요인의 상대적 중요도와 우선순위를 제안하고자 한다. 연구방법으로는 SWOT요인들의 중요도를 분석하기 위해 AHP분석과 ANP분석을 실시하였으며 호환성에 문제가 없어 AHP 분석 결과를 활용하여 중요도 분석을 하였다. 분석결과 첫째, SWOT 분석에서 내부적 요인 중 강점요인을 약점요인보다 중요하게 생각하고 있으며 외부적 요인 중 기회요인을 위기요인보다 중요하게 생각하고 있는 것으로 나타났다. 이는 국내 외식프랜차이즈 사업이 갖는 약점요인과 위기요인이 있긴 하지만 이러한 부정적인 요인보다는 강점요인과 기회요이 갖는 긍정적인 점을 더 중요하게 판단하여 국내 외식프랜차이즈의 전체적인 성장 가능성을 높이 평가한 결과라 할 것이다. 둘째, 강점요인 중에서는 업체그룹은 검증된 비즈니스모델 사용으로 사업안정화(S3)가 가장 중요도가 높았으며 전문가그룹은 가맹본부의 표준화된 제품(서비스) 및 경영지원(S2)이 가장 중요도가 높았다. 셋째, 약점요인 중에는 가맹본부와의 불리한 지위에서 협상 및 해결(W3)과 계약기간 내 계약파기 어려움과 파기 시 막대한 손실발생(W4)의 중요도 합계가 60%에 이른다. 넷째, 기회요인 중에서는 라이프 스타일, 가치관, 소비의식 구조의 변화(O3)가 압도적으로 중요하게 나왔다. 다섯째, 위기요인 중에서는 소비시장이 다양화에 따른 고객의 욕구변화(T1)를 가장 중요하게 생각하는 것으로 나타났다. 향후 다양하게 변할 소비자의 욕구를 어떻게 만족시킬 것인가가 국내 외식프랜차이즈의 위기를 극복하는 가장 중요한 요인임을 반증하고 있다 할 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권7호
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• pp.1044-1052
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• 2015

The aim of this modelling study was to investigate the effect of large herd size (and land areas) on walking distances and milking interval (MI), and their impact on milk yield and economic penalties when 50% of the total diets were provided from home grown feed either as pasture or grazeable complementary forage rotation (CFR) in an automatic milking system (AMS). Twelve scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as 'moderate'; optimum pasture utilisation of 19.7 t DM/ha, termed as 'high') and 2 rates of incorporation of grazeable complementary forage system (CFS: 0, 30%; CFS = 65% farm is CFR and 35% of farm is pasture) were investigated. Walking distances, energy loss due to walking, MI, reduction in milk yield and income loss were calculated for each treatment based on information available in the literature. With moderate pasture utilisation and 0% CFR, increasing the herd size from 400 to 800 cows resulted in an increase in total walking distances between the parlour and the paddock from 3.5 to 6.3 km. Consequently, MI increased from 15.2 to 16.4 h with increased herd size from 400 to 800 cows. High pasture utilisation (allowing for an increased stocking density) reduced the total walking distances up to 1 km, thus reduced the MI by up to 0.5 h compared to the moderate pasture, 800 cow herd combination. The high pasture utilisation combined with 30% of the farm in CFR in the farm reduced the total walking distances by up to 1.7 km and MI by up to 0.8 h compared to the moderate pasture and 800 cow herd combination. For moderate pasture utilisation, increasing the herd size from 400 to 800 cows resulted in more dramatic milk yield penalty as yield increasing from c.f. 2.6 and 5.1 kg/cow/d respectively, which incurred a loss of up to $AU 1.9/cow/d. Milk yield losses of 0.61 kg and 0.25 kg for every km increase in total walking distance (voluntary return trip from parlour to paddock) and every one hour increase in MI, respectively. The high pasture utilisation combined with 30% of the farm in CFR in the farm increased milk yield by up to 1.5 kg/cow/d, thereby reducing loss by up to $0.5/cow/d (c.f. the moderate pasture and 800 cow herd scenario). Thus, it was concluded that the successful integration of grazeable CFS with pasture has the potential to improve financial performance compared to the pasture only, large herd, AMS.

• 한국콘텐츠학회논문지
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• 제19권12호
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• pp.615-622
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• 2019

근래 인도에서의 잔혹한 집단 성폭행 사건에 대한 보도를 자주 접하고 있다. 인도에서 가장 부각된 집단 성폭행 사건은 2012년 의대생인 조티 싱을 버스에서 6명이 집단 성폭행한 후 성기와 장기를 손상해 사망하게 만든 사건이다. 이 사건을 계기로 성폭행에 대해 사형까지도 포함한 강력한 처벌 법안이 발의되고 통과되었다. 그러나 그 이후로도 성폭행은 여전히 증가하고 있다. 이에 성폭행 사건 발생지역을 중심으로 지역적 특성과의 연관성을 살펴본 결과, 언론에 보도된 집단 성폭행 사례의 대부분이 인도 중북부에서 발생하는 것으로 나타났으며, 이것은 지역적으로 힌두 강세지역과 일치하는 것을 확인하였다. 그렇다면 그 원인은 여성 경시가 심각한 힌두 근본주의가 그 원인이라고 결론 내릴 수밖에 없다. 힌두 근본주의자들은 강한 복고주의적 경향을 가지고 여성에 관한 전통적 가치를 부활시키려 한다. 인도 사회에서 여성은 아직도 종속적인 피해 위험에 노출되어 있다. 집권당과 정치지도자들의 힌두 근본주의 노선 추구는 인도 여성의 사회적 지위와 인권을 개선하는 데는 많은 시간이 더 필요할 것으로 보인다.

• 응용통계연구
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• 제37권1호
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• pp.1-12
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• 2024

동일한 설명변수 집합에 여러 개의 반응 변수들이 종속되어 있는 경우를 많은 실제 자료에서 볼 수 있다. 특히, 여러 개의 반응변수가 서로 상관관계를 가지고 있으면 각각의 반응변수에 대한 개별적인 분석보다는 반응변수들 사이의 상관관계를 고려한 동시 추정(simultaneous estimation)이 매우 효과적이다. 이러한 다변량 회귀분석에서 최소거리추정량(least distance estimator; LDE)은 반응변수들간의 상관관계를 모형 적합 과정에 반영하여 다차원 유클리드 공간에서 각 훈련 개체와 추정값 사이의 거리를 최소화하도록 회귀계수들을 동시에 추정한다. 뿐만 아니라 최소거리추정량은 이상치에 대한 강건성을 제공한다. 본 논문에서는 다변량 선형 회귀분석에서의 최소거리추정법에 대해 살펴보고, 나아가 효율적인 변수선택을 위한 벌점화 최소거리추정량을 제시하였다. 본 연구에서 제안하는 adaptive group LASSO 벌점항을 적용한 AGLDE 기법은 반응변수들간의 상관관계를 모형 적합에 반영함과 동시에 설명변수의 중요도에 따라 효율적으로 변수선택을 수행할 수 있다. 제안 방법의 유용성은 모의실험과 실제 자료 분석을 통해 확인하였다.

• 대한조선학회논문집
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• 제50권3호
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• pp.175-181
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• 2013

This paper presents a simulation for passenger ship evacuation considering the inclination of a ship. In order to describe a passenger's behavior in an evacuation situation, a passenger is modeled as a rigid body which translates in the horizontal plane and rotates along the vertical axis. The position and rotation angle of a passenger are calculated by solving the dynamic equations of motions at each time step. To calculate inclined angle of damaged ship, static equilibrium equations of damaged ship are derived using "added weight method". Using these equations, physical external forces due to the inclination of a ship act on the body of each passenger. The crowd behavior of the passenger is considered as the flock behavior, a form of collective behavior of a large number of interacting passengers with a common group objective. Passengers can also avoid an obstacle due to penalty forces acting on their body. With the passenger model and forces acting on its body, the test problems in International Maritime Organization, Maritime Safety Committee/Circulation 1238(IMO MSC/Circ.1238) are implemented and the effects of ship's inclination on the evacuation time are confirmed.

• 대한전자공학회논문지TC
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• 제43권1호
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• pp.89-94
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• 2006

준정적 플랫 페이딩 환경에서 시공간 트렐리스 부호의 준최적 복호법인 principal ratio combining(PRC) 기법[1]의 일반화된 버전을 제안한다. [1]에서는 수신 안테나의 수가 증가함에 따라 성능 저하 폭이 증가하는 문제가 있다. 제안하는 방식은 수신 안테나들을 K개의 그룹으로 나누어 각 그룹에 PRC 기법을 적용하는 일반화된 PRC 기법이다. 일반화된 PRC에서는 수신 안테나의 수가 증가하여도 기존의 PRC 기법에 비해 성능 저하 폭이 상당히 감소한다. 그러나 복호기의 복잡도는 다소 증가한다. 따라서 시스템의 QoS(qualify of service), 성능 및 복잡도의 tradeoff에서 적당한 K를 선택해야만 한다 또한, 수신 안테나 수가 증가함에 따라, K개로 그룹핑하는 방법이 여러 가지 나을 수 있는데, 각 경우에 최종 성능 차이를 간단히 예측할 수 있는 성능지표(performance index, PI)를 제안한다.

• 대한조선학회논문집
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• 제50권5호
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• pp.307-313
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• 2013

This paper presents a simulation for passenger ship evacuation considering determination of evacuating direction based on walking direction potential function. In order to determine walking direction of a passenger, his/her position in two dimensional plane was adopted as a design variable, and fixed boundaries such as walls and obstacles were adopted as constraints. To solve this optimum problem, a walking direction potential function was adopted as an objective function. This potential function was configured as a kind of penalty function and it contained two components. One is a potential function concerned with the distance to the destination, and other is a potential function based on the effect of walls and obstacles. To determine evacuating direction, this problem was solved by minimizing the walking direction potential function every unit time during the simulation. The crowd behavior of the passenger consisted of the flock behavior, a form of collective behavior of a large number of interacting passengers with a common group. With the proposed algorithm, the test problems in International Maritime Organization, Maritime Safety Committee/Circulation 1238(IMO MSC/Circ.1238) were implemented and the direction of passengers and total evacuation time was analyzed.

• 한국병원경영학회지
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• 제22권3호
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• pp.74-87
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• 2017

Purposes: The purpose is to establish the direction of healthcare R&D through private nonprofit organization. Methodology: The data is divided into two groups: 12 physicians and pharmacists, and 16 persons including professors related to university donation, non-profit foundation executives. Each group was subjected to two Delphi surveys. To analyze the validity of the opinion, the content validity ratio and the consensus of experts were verified. Findings: Funding should be invested in 'development research' and 'application research'. The factors that hinder the donation culture are 'donation prevention system such as tax imposition system and rebate double penalty system', 'insufficient motivation of fund raising person', and 'lack of fund specializing specialist'. The fund raising strategy should be centered on a small number of large donors or a balance between large and small donors. The fund raising target should be effective to raise funds for corporate and individual donors. It is necessary to clarify the purpose of the social problem to be solved by the campaign strategy for promoting donation, to announce the validity of the trust and transparency of the institution, and to emphasize the social investment by the private sector. Practical Implications: It is necessary to present directions through private nonprofit organizations for the future development of healthcare R&D. The legal and institutional deficiencies of the domestic nonprofit organization fundraising infrastructure should be improved. In order to create a social investment climate, it is necessary to improve the awareness of donations and develop various donation programs for the private sector.

• 한국병원경영학회지
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• 제22권4호
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• pp.50-60
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• 2017

Purposes: The purpose of this study was to identify the preferred types of the hospital reservation cancellation management to help reduce the reservation cancellations. Methodology: This study sampled 327 outpatients or their guardians who had reserved a university hospital and a general hospital located in the southwestern part of Seoul, and the responses from 300 of them were used for the final analysis. The subjects' preferences of reservation cancellation management types were analyzed in reference to their demographic variables. The timing and frequency of pre-notification preferred by the subjects were examined. A multidimensional scaling methods and correspondence analysis was used to identify preference for management methods of no-show and type of reservation guide. Findings: As a result, 77.3% of the respondents were perceived that the reservation cancellation was a habit. The most preferred method of managing the reservation cancellation would be refusal to refund the reservation deposit (61.7%), followed by payment for cancellation (16.0%), limit of future reservations (16.0%) and penalty (6.3%) in their order. 186 of the subjects (62.0%) preferred the texting for prevention of reservation cancellations, and 102 of the subjects (34.0%) preferred the phone calls. The preferred timing and frequency of the SMS were twice 3 days before, once a day before and three times 7 days before, while the preferred timing and frequency of phone call was once a day before. Practical Implications: The no-show rate can be improved by enhancing SMS pre-notification and by improving afterwards telephone counseling. For other factors, it needs to study on the service differentiation with the characteristics of each patient group.