• 제목/요약/키워드: Rapid Product Development

검색결과 348건 처리시간 0.03초

스마트폰의 지각된 가치와 지속적 사용의도, 그리고 개인 혁신성의 조절효과 (An Empirical Study on Perceived Value and Continuous Intention to Use of Smart Phone, and the Moderating Effect of Personal Innovativeness)

  • 한준형;강성배;문태수
    • Asia pacific journal of information systems
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    • 제23권4호
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    • pp.53-84
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    • 2013
  • With rapid development of ICT (Information and Communications Technology), new services by the convergence of mobile network and application technology began to appear. Today, smart phone with new ICT convergence network capabilities is exceedingly popular and very useful as a new tool for the development of business opportunities. Previous studies based on Technology Acceptance Model (TAM) suggested critical factors, which should be considered for acquiring new customers and maintaining existing users in smart phone market. However, they had a limitation to focus on technology acceptance, not value based approach. Prior studies on customer's adoption of electronic utilities like smart phone product showed that the antecedents such as the perceived benefit and the perceived sacrifice could explain the causality between what is perceived and what is acquired over diverse contexts. So, this research conceptualizes perceived value as a trade-off between perceived benefit and perceived sacrifice, and we need to research the perceived value to grasp user's continuous intention to use of smart phone. The purpose of this study is to investigate the structured relationship between benefit (quality, usefulness, playfulness) and sacrifice (technicality, cost, security risk) of smart phone users, perceived value, and continuous intention to use. In addition, this study intends to analyze the differences between two subgroups of smart phone users by the degree of personal innovativeness. Personal innovativeness could help us to understand the moderating effect between how perceptions are formed and continuous intention to use smart phone. This study conducted survey through e-mail, direct mail, and interview with smart phone users. Empirical analysis based on 330 respondents was conducted in order to test the hypotheses. First, the result of hypotheses testing showed that perceived usefulness among three factors of perceived benefit has the highest positive impact on perceived value, and then followed by perceived playfulness and perceived quality. Second, the result of hypotheses testing showed that perceived cost among three factors of perceived sacrifice has significantly negative impact on perceived value, however, technicality and security risk have no significant impact on perceived value. Also, the result of hypotheses testing showed that perceived value has significant direct impact on continuous intention to use of smart phone. In this regard, marketing managers of smart phone company should pay more attention to improve task efficiency and performance of smart phone, including rate systems of smart phone. Additionally, to test the moderating effect of personal innovativeness, this research conducted multi-group analysis by the degree of personal innovativeness of smart phone users. In a group with high level of innovativeness, perceived usefulness has the highest positive influence on perceived value than other factors. Instead, the analysis for a group with low level of innovativeness showed that perceived playfulness was the highest positive factor to influence perceived value than others. This result of the group with high level of innovativeness explains that innovators and early adopters are able to cope with higher level of cost and risk, and they expect to develop more positive intentions toward higher performance through the use of an innovation. Also, hedonic behavior in the case of the group with low level of innovativeness aims to provide self-fulfilling value to the users, in contrast to utilitarian perspective, which aims to provide instrumental value to the users. However, with regard to perceived sacrifice, both groups in general showed negative impact on perceived value. Also, the group with high level of innovativeness had less overall negative impact on perceived value compared to the group with low level of innovativeness across all factors. In both group with high level of innovativeness and with low level of innovativeness, perceived cost has the highest negative influence on perceived value than other factors. Instead, the analysis for a group with high level of innovativeness showed that perceived technicality was the positive factor to influence perceived value than others. However, the analysis for a group with low level of innovativeness showed that perceived security risk was the second high negative factor to influence perceived value than others. Unlike previous studies, this study focuses on influencing factors on continuous intention to use of smart phone, rather than considering initial purchase and adoption of smart phone. First, perceived value, which was used to identify user's adoption behavior, has a mediating effect among perceived benefit, perceived sacrifice, and continuous intention to use smart phone. Second, perceived usefulness has the highest positive influence on perceived value, while perceived cost has significant negative influence on perceived value. Third, perceived value, like prior studies, has high level of positive influence on continuous intention to use smart phone. Fourth, in multi-group analysis by the degree of personal innovativeness of smart phone users, perceived usefulness, in a group with high level of innovativeness, has the highest positive influence on perceived value than other factors. Instead, perceived playfulness, in a group with low level of innovativeness, has the highest positive factor to influence perceived value than others. This result shows that early adopters intend to adopt smart phone as a tool to make their job useful, instead market followers intend to adopt smart phone as a tool to make their time enjoyable. In terms of marketing strategy for smart phone company, marketing managers should pay more attention to identify their customers' lifetime value by the phase of smart phone adoption, as well as to understand their behavior intention to accept the risk and uncertainty positively. The academic contribution of this study primarily is to employ the VAM (Value-based Adoption Model) as a conceptual foundation, compared to TAM (Technology Acceptance Model) used widely by previous studies. VAM is useful for understanding continuous intention to use smart phone in comparison with TAM as a new IT utility by individual adoption. Perceived value dominantly influences continuous intention to use smart phone. The results of this study justify our research model adoption on each antecedent of perceived value as a benefit and a sacrifice component. While TAM could be widely used in user acceptance of new technology, it has a limitation to explain the new IT adoption like smart phone, because of customer behavior intention to choose the value of the object. In terms of theoretical approach, this study provides theoretical contribution to the development, design, and marketing of smart phone. The practical contribution of this study is to suggest useful decision alternatives concerned to marketing strategy formulation for acquiring and retaining long-term customers related to smart phone business. Since potential customers are interested in both benefit and sacrifice when evaluating the value of smart phone, marketing managers in smart phone company has to put more effort into creating customer's value of low sacrifice and high benefit so that customers will continuously have higher adoption on smart phone. Especially, this study shows that innovators and early adopters with high level of innovativeness have higher adoption than market followers with low level of innovativeness, in terms of perceived usefulness and perceived cost. To formulate marketing strategy for smart phone diffusion, marketing managers have to pay more attention to identify not only their customers' benefit and sacrifice components but also their customers' lifetime value to adopt smart phone.

국제통화제도의 개혁과 G20 (International Monetary System Reform and the G20)

  • 조윤제
    • KDI Journal of Economic Policy
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    • 제32권4호
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    • pp.153-195
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    • 2010
  • 세계금융위기의 근본적인 원인은 시장과 제도의 괴리에서 나오는 '제도의 실패'라고 할 수 있다. 특히 현재의 국제통화제도는 무제도(non-system)나 다름없다고 할 수 있다. 현재 당면하고 있는 국제통화제도의 문제점들을 볼 때 개편 방향의 핵심은 (1) 수요 측면에서는 과대한 외환보유고를 축적하려는 인센티브를 어떻게 줄일 수 있을 것인가 하는 것이며, (2) 공급 측면에서는 현재 미국 달러화에 주로 의존하고 있는 제도를 탈피, 보다 다양한 국제통화 혹은 대체적 외화준비자산(SDR을 포함하여)으로 전환해 나가거나 혹은 보다 근본적인 개혁방안으로서 새로운 세계통화(global reserve currency)를 창출하는 것이다. 그리고 (3) 이러한 변화를 뒷받침 하기 위해 필요한 기구적 개편, 특히 IMF의 개혁을 추진하는 것이다. 이러한 개편은 현실적 국제역학관계로 볼 때 오직 점진적으로 일어날 수 있는 것이다. 따라서 현재 세계경제의 안정적 성장을 위해 중요한 것은 이러한 개편을 점진적으로 추진함과 동시에 주요국 간의 거시경제정책공조를 이뤄 나가는 것이다. 이러한 과정을 원활히 해나가기 위해서는 효율적인 세계경제 지배구조를 갖추는 것이 필수적이다. 세계금융위기 이후 출범한 G20 정상회의가 효율적인 협의체가 되기 위해서는 의사결정이 원활히 이루어질 수 있는 방안과 장치를 세워나갈 필요가 있다. 사무국(secretariat) 혹은 그와 유사한 기능을 행사할 수 있는 조직의 설립과 위원회제도 같은 것을 활용할 필요가 있을 것으로 보인다.

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PCR을 이용한 식품 중 알레르기 유발물질 검출법 개발 (Development of PCR Method for Rapid Detection of Allergic Materials in Foods)

  • 박용춘;김미라;신준호;김규헌;이재황;조태용;이화정;이상재;한상배
    • 한국식품위생안전성학회지
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    • 제28권2호
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    • pp.124-129
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    • 2013
  • 본 연구에서는 분자생물학적 방법을 통한 알레르기 유발 원재료 확인을 위해 PCR방법의 최적 조건을 구축하였다. 가공식품에서 알레르기 원료성분 확인을 위하여 200bp 내외의 PCR 산물을 생성할 수 있는 종특이 프라이머를 설계하거나 선행연구사업 결과를 활용하였다. 대상 원료로는 국내 식품알레르기 표시대상인 난류, 우유, 메밀, 땅콩, 대두, 밀, 고등어, 게, 새우, 돼지고기, 복숭아 및 토마토와 제외국에서 알레르기 유발 성분으로 규정하고있는 아몬드, 참깨를 포함하여 총 14종을 대상으로 하였다. 특이 프라이머를 사용하여 PCR 한 결과 난류, 우유, 메밀, 땅콩, 대두, 밀, 고등어, 게, 새우, 돼지고기, 복숭아, 토마토, 아몬드 및 참깨로부터 각각 281, 131, 138, 120, 118, 127, 211, 174, 231, 138, 174, 132, 103 및 220bp의 특이 밴드를 확인하였으며 상호간의 비 특이적 밴드는 검출되지 않았다. 본 연구에서 확립한 알레르기 유발 원재료 검출법은 식품의 부정확한 표시나 가공식품의 제조과정 중 알레르기 유발물질의 비의도적 혼입 등으로부터 소비자를 보호하고 향후 수출 제품에 있어서 정확한 알레르기 유발원재료 표기에 활용이 가능할 것으로 판단된다.

고 기능성 수질 정화 여과재로서의 장석질 모래 활용연구 (A Study of the Utilization of Feldspathic Sand as a Fortified Functional Filtering Material for Water Purification)

  • 고상모;송민섭;홍석정
    • 한국광물학회지
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    • 제16권4호
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    • pp.283-293
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    • 2003
  • 국내 정수장에서는 여과사를 이용하여 원수를 정수하는 급속 및 완속 여과시스템을 이용하고있다. 대부분의 여과사는 해사인 규사로써, 구성광물의 광물학적 특성이 매우 제한되어 중금속이나 유기 오염물의 여과능력이 높은 편이 아니다. 따라서 항상 예기치 않게 발생될 수 있는 오염된 원수를 효율적이고 경제적으로 여과할 수 있는 여과물질 개발이 요구되고 있다. 따라서 이 연구에서 해사를 대체할 수 있는 화강암 풍화산물인 장석질 모래에 일정량의 불석을 혼화하여 원수를 여과하였을 때 일어나는 지화학성의 변화 및 Cd, Cu, Pb와 같은 중금속의 제거능력을 시험하였다. 시험 대상 물질은 현재 정수장에서 사용하는 주문진 규사와 이 연구에서 제조된 장석질 여과사, 장석질 혼합사 I(불석 10% 혼화), 장석질 혼합사 II(불석 20% 혼화)이다. 장석질 혼합사 I 및 II는 주문진 규사와 장석질 여과사에 비해 대부분의 양이온 및 음이온이 높게 용출되었으며, Si, Ca, $SO_4$ 이온 용출은 Al,$ NO_3$, Fe, K, Mg, P 에 비해 높게 일어났다. 제올라이트의 함량을 높인 혼합사 II가 혼합사 I 비해 Na, Ca, Al과 같은 양이온의 용출농도가 보다 높게 일어났으며, 이 양이온들은 크리높틸로라이트 계열의 제올라이트로부터 주로 용출되었다. 주문진 규사와 장석질 여과사는 Cd, Cu, Pb에 대해 제거능이 거의 없거나 약한 제거율을 보였다. 이에 반하여 장석질 혼합사I, II는 Cd과 Cu에 대해 낮은 제거율을 보였으나 Pb에 대해서는 상대적으로 매우 높은 제거율을 보였다. 장석질 혼합사 I, II는 저농도(100 ppm)의 Cd, Cu, Pb에 대하여 비교적 높은 제거율을 보이는 것으로 나타났으며, 장석질 혼합사 II는 저농도(100 ppm)의 Pb 용액과 반응시킨 경우 상당히 높은 제거율 (90.7%)을 보였다. 고농도(500 ppm) 영역에서는 장석질 혼합사 I, II는 Cd의 흡착량이 Cu, Pb에 비하여 높게 나타났으며, 제거율도 각각 24.0%, 28.2%로 가장 높게 나타났다. 제올라이트의 혼합비가 10%에서 20%로 증가할수록 중금속의 흡착량과 제거율이 향상되었다. 이는 장석질 혼합사를 여과사로 이용 할 경우 제올라이트를 적정 비율로 혼화하면 높은 중금속 제거 효과가 있는 것으로 판단된다.

영역별 맞춤형 감성사전 구축을 통한 영화리뷰 감성분석 (Sentiment analysis on movie review through building modified sentiment dictionary by movie genre)

  • 이상훈;최정;김종우
    • 지능정보연구
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    • 제22권2호
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    • pp.97-113
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    • 2016
  • 인터넷상의 데이터가 급속하게 증가함에 따라 막대한 양의 데이터를 목적에 맞게 적절히 활용하는 빅데이터 분석이 활발하게 진행되고 있다. 최근에는 기존의 정형 데이터분석이 가진 한계점을 보완하는 방법으로 비정형 데이터 분석 분야 중 하나인 텍스트마이닝 기법에 대한 연구들이 다수 이루어지고 있으며, 특히 텍스트를 기반으로 문장의 긍정, 부정을 판별하고 분류하는 감성분석과 관련된 연구들이 활발하게 이루어지고 있다. 이러한 연구의 연장선 상에서, 본 연구는 감성분석에 사용되는 감성사전을 데이터의 특성에 맞게 적절하게 변형하여 구축하는 방법을 시도하였다. 데이터가 속한 영역의 특성을 고려하지 않은 기존의 범용 감성사전을 감성분석에 사용할 경우, 해당 영역에서 쓰이는 단어 또는 감정 표현을 반영하지 못하므로 감성분석의 정확성이 떨어질 수 있다. 따라서 감성분석에 있어서 영역 맞춤형 감성사전의 사용 시 데이터 영역의 특성을 정확하게 반영해 분석의 정확성을 높여줄 것으로 기대할 수 있다. 본 연구에서는 영화 리뷰 데이터를 분석 대상으로 선정하였으며, 대표적 영화정보 사이트 IMDb에서 발생된 약 2년간의 영화리뷰 데이터를 수집 분석하였다. 분석에 앞서 영화 장르별 사용되는 단어의 의미가 각각 다를 것을 고려하여 영화를 '액션', '애니메이션', '코메디', '드라마', '공포', '과학공상' 6개 장르로 분류했다. 맞춤형 감성사전 구축을 위한 핵심 기법으로 SO-PMI(Semantic Orientation from Point-wise Mutual Information)를 활용하였으며, 어휘 간 극성이 뚜렷하게 구분되는 형용사에 한정하여 연구를 진행했다. 분석결과 맞춤형사전을 활용한 감성분석 예측정확도는 영화 장르별로 상이했다. '애니메이션'을 제외한 5개 장르에서 기존의 범용 감성사전대비 맞춤형 감성사전의 예측정확도가 통계적으로 유의한 수준의 성능 향상을 보였다. 본 연구에서는 데이터 영역의 특성에 맞는 맞춤형 사전 구축을 통한 감성분석의 예측의 성능 향상을 확인하였다. 향후 감성사전 구축 시 동사, 부사 등 다양한 품사의 어휘를 추가하여 감성분석 예측정확도를 높이는 방안을 모색할 수 있을 것이다.

사용자 리뷰의 평가기준 별 이슈 식별 방법론: 호텔 리뷰 사이트를 중심으로 (Methodology for Identifying Issues of User Reviews from the Perspective of Evaluation Criteria: Focus on a Hotel Information Site)

  • 변성호;이동훈;김남규
    • 지능정보연구
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    • 제22권3호
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    • pp.23-43
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    • 2016
  • 최근 IT기술의 발전에 따라 많은 사람들이 자신들의 여가활동에 대한 경험을 공유하고 있으며, 역으로 다른 사람들의 여가활동에 대한 경험을 참고하여 더 나은 여가활동을 누릴 수 있는 기회를 얻게 되었다. 이러한 현상은 영화, 숙박, 음식, 여행 등 여가활동 전반에 걸쳐 나타나고 있으며, 그 중심에는 여가활동에 대한 정보를 요약하여 제공하는 수많은 사이트가 있다. 대부분의 여가활동 정보 사이트는 각 상품에 대한 평균 평점뿐만 아니라 상세 리뷰를 제공함으로써, 해당 상품을 구매하고자 하는 잠재고객의 의사결정을 지원하고 있다. 하지만 기존 대부분의 사이트는 한 단계의 평가기준에 따라 평점과 리뷰를 제공하기 때문에, 각 평가기준을 구성하는 세부요소에 대한 특징과 평가기준 별 주요 이슈를 파악하기 위해서는 상당히 많은 수의 리뷰를 직접 읽어야 한다는 불편이 따른다. 즉 사용자는 자신이 중요한 것으로 생각하는 평가기준에 대한 조건을 파악하기 위해, 많은 수의 리뷰를 하나하나 읽어보는 과정에서 많은 시간과 노력을 소비하게 된다. 예를 들어 호텔의 접근성, 객실, 서비스, 음식 등 한 단계의 평가기준만을 사용하여 평점과 리뷰를 제공하는 사이트의 경우, 접근성 중 특히 지하철역과의 거리, 객실 중 특히 욕실의 상태를 살펴보고자 하는 사용자에게 필요한 정보를 충분히 제공하지 못하게 된다. 따라서 본 연구에서는 기존 여가활동 정보 사이트의 한계, 즉 평가기준별로 입력된 리뷰를 신뢰하기 어렵다는 점과 평가기준을 구성하고 있는 세부 내용을 파악하기 어렵다는 점을 극복하기 위한 방안을 제시하고자 한다. 본 연구에서 제안하는 방법론은 사용자가 별도의 구분 없이 입력한 리뷰를 그 내용에 따라 평가기준별로 자동 분류하고, 각 평가 기준 별 주요 이슈를 요약하여 제공한다. 제안 방법론은 최근 텍스트 분석에 활발하게 사용되고 있는 토픽 모델링(Topic Modeling)에 기반을 두고 있으며, 각 리뷰를 하나의 문서 단위로 사용하는 것이 아니라 리뷰를 문장 단위로 끊어 개별 리뷰 유닛(Review Unit)으로 분해한 뒤, 평가기준별로 리뷰 유닛을 재구성하여 분석한다는 측면에서 기존의 토픽 모델링 기반 연구와 큰 차이가 있다고 할 수 있다. 본 논문에서는 제안 방법론을 실제 호텔 정보 사이트에서 수집한 423건의 리뷰 문서에 적용하여 6가지 평가기준에 대해 총 4,860건의 리뷰 유닛을 재구성하고, 이에 대한 분석 결과를 소개함으로써 제안 방법론의 유용성을 간접적으로 보인다.

참여자관점에서 공급사슬관리 시스템의 성공에 영향을 미치는 요인에 관한 실증연구 (An Empirical Study on the Determinants of Supply Chain Management Systems Success from Vendor's Perspective)

  • 강성배;문태수;정윤
    • Asia pacific journal of information systems
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    • 제20권3호
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    • pp.139-166
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    • 2010
  • The supply chain management (SCM) systems have emerged as strong managerial tools for manufacturing firms in enhancing competitive strength. Despite of large investments in the SCM systems, many companies are not fully realizing the promised benefits from the systems. A review of literature on adoption, implementation and success factor of IOS (inter-organization systems), EDI (electronic data interchange) systems, shows that this issue has been examined from multiple theoretic perspectives. And many researchers have attempted to identify the factors which influence the success of system implementation. However, the existing studies have two drawbacks in revealing the determinants of systems implementation success. First, previous researches raise questions as to the appropriateness of research subjects selected. Most SCM systems are operating in the form of private industrial networks, where the participants of the systems consist of two distinct groups: focus companies and vendors. The focus companies are the primary actors in developing and operating the systems, while vendors are passive participants which are connected to the system in order to supply raw materials and parts to the focus companies. Under the circumstance, there are three ways in selecting the research subjects; focus companies only, vendors only, or two parties grouped together. It is hard to find researches that use the focus companies exclusively as the subjects probably due to the insufficient sample size for statistic analysis. Most researches have been conducted using the data collected from both groups. We argue that the SCM success factors cannot be correctly indentified in this case. The focus companies and the vendors are in different positions in many areas regarding the system implementation: firm size, managerial resources, bargaining power, organizational maturity, and etc. There are no obvious reasons to believe that the success factors of the two groups are identical. Grouping the two groups also raises questions on measuring the system success. The benefits from utilizing the systems may not be commonly distributed to the two groups. One group's benefits might be realized at the expenses of the other group considering the situation where vendors participating in SCM systems are under continuous pressures from the focus companies with respect to prices, quality, and delivery time. Therefore, by combining the system outcomes of both groups we cannot measure the system benefits obtained by each group correctly. Second, the measures of system success adopted in the previous researches have shortcoming in measuring the SCM success. User satisfaction, system utilization, and user attitudes toward the systems are most commonly used success measures in the existing studies. These measures have been developed as proxy variables in the studies of decision support systems (DSS) where the contribution of the systems to the organization performance is very difficult to measure. Unlike the DSS, the SCM systems have more specific goals, such as cost saving, inventory reduction, quality improvement, rapid time, and higher customer service. We maintain that more specific measures can be developed instead of proxy variables in order to measure the system benefits correctly. The purpose of this study is to find the determinants of SCM systems success in the perspective of vendor companies. In developing the research model, we have focused on selecting the success factors appropriate for the vendors through reviewing past researches and on developing more accurate success measures. The variables can be classified into following: technological, organizational, and environmental factors on the basis of TOE (Technology-Organization-Environment) framework. The model consists of three independent variables (competition intensity, top management support, and information system maturity), one mediating variable (collaboration), one moderating variable (government support), and a dependent variable (system success). The systems success measures have been developed to reflect the operational benefits of the SCM systems; improvement in planning and analysis capabilities, faster throughput, cost reduction, task integration, and improved product and customer service. The model has been validated using the survey data collected from 122 vendors participating in the SCM systems in Korea. To test for mediation, one should estimate the hierarchical regression analysis on the collaboration. And moderating effect analysis should estimate the moderated multiple regression, examines the effect of the government support. The result shows that information system maturity and top management support are the most important determinants of SCM system success. Supply chain technologies that standardize data formats and enhance information sharing may be adopted by supply chain leader organization because of the influence of focal company in the private industrial networks in order to streamline transactions and improve inter-organization communication. Specially, the need to develop and sustain an information system maturity will provide the focus and purpose to successfully overcome information system obstacles and resistance to innovation diffusion within the supply chain network organization. The support of top management will help focus efforts toward the realization of inter-organizational benefits and lend credibility to functional managers responsible for its implementation. The active involvement, vision, and direction of high level executives provide the impetus needed to sustain the implementation of SCM. The quality of collaboration relationships also is positively related to outcome variable. Collaboration variable is found to have a mediation effect between on influencing factors and implementation success. Higher levels of inter-organizational collaboration behaviors such as shared planning and flexibility in coordinating activities were found to be strongly linked to the vendors trust in the supply chain network. Government support moderates the effect of the IS maturity, competitive intensity, top management support on collaboration and implementation success of SCM. In general, the vendor companies face substantially greater risks in SCM implementation than the larger companies do because of severe constraints on financial and human resources and limited education on SCM systems. Besides resources, Vendors generally lack computer experience and do not have sufficient internal SCM expertise. For these reasons, government supports may establish requirements for firms doing business with the government or provide incentives to adopt, implementation SCM or practices. Government support provides significant improvements in implementation success of SCM when IS maturity, competitive intensity, top management support and collaboration are low. The environmental characteristic of competition intensity has no direct effect on vendor perspective of SCM system success. But, vendors facing above average competition intensity will have a greater need for changing technology. This suggests that companies trying to implement SCM systems should set up compatible supply chain networks and a high-quality collaboration relationship for implementation and performance.

한국주요빙계의 소유역에 대한 순간단위권 유도에 관한 연구 (I) (Studies on the Derivation of the Instantaneous Unit Hydrograph for Small Watersheds of Main River Systems in Korea)

  • 이순혁
    • 한국농공학회지
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    • 제19권1호
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    • pp.4296-4311
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    • 1977
  • This study was conducted to derive an Instantaneous Unit Hydrograph for the accurate and reliable unitgraph which can be used to the estimation and control of flood for the development of agricultural water resources and rational design of hydraulic structures. Eight small watersheds were selected as studying basins from Han, Geum, Nakdong, Yeongsan and Inchon River systems which may be considered as a main river systems in Korea. The area of small watersheds are within the range of 85 to 470$\textrm{km}^2$. It is to derive an accurate Instantaneous Unit Hydrograph under the condition of having a short duration of heavy rain and uniform rainfall intensity with the basic and reliable data of rainfall records, pluviographs, records of river stages and of the main river systems mentioned above. Investigation was carried out for the relations between measurable unitgraph and watershed characteristics such as watershed area, A, river length L, and centroid distance of the watershed area, Lca. Especially, this study laid emphasis on the derivation and application of Instantaneous Unit Hydrograph (IUH) by applying Nash's conceptual model and by using an electronic computer. I U H by Nash's conceptual model and I U H by flood routing which can be applied to the ungaged small watersheds were derived and compared with each other to the observed unitgraph. 1 U H for each small watersheds can be solved by using an electronic computer. The results summarized for these studies are as follows; 1. Distribution of uniform rainfall intensity appears in the analysis for the temporal rainfall pattern of selected heavy rainfall event. 2. Mean value of recession constants, Kl, is 0.931 in all watersheds observed. 3. Time to peak discharge, Tp, occurs at the position of 0.02 Tb, base length of hlrdrograph with an indication of lower value than that in larger watersheds. 4. Peak discharge, Qp, in relation to the watershed area, A, and effective rainfall, R, is found to be {{{{ { Q}_{ p} = { 0.895} over { { A}^{0.145 } } }}}} AR having high significance of correlation coefficient, 0.927, between peak discharge, Qp, and effective rainfall, R. Design chart for the peak discharge (refer to Fig. 15) with watershed area and effective rainfall was established by the author. 5. The mean slopes of main streams within the range of 1.46 meters per kilometer to 13.6 meter per kilometer. These indicate higher slopes in the small watersheds than those in larger watersheds. Lengths of main streams are within the range of 9.4 kilometer to 41.75 kilometer, which can be regarded as a short distance. It is remarkable thing that the time of flood concentration was more rapid in the small watersheds than that in the other larger watersheds. 6. Length of main stream, L, in relation to the watershed area, A, is found to be L=2.044A0.48 having a high significance of correlation coefficient, 0.968. 7. Watershed lag, Lg, in hrs in relation to the watershed area, A, and length of main stream, L, was derived as Lg=3.228 A0.904 L-1.293 with a high significance. On the other hand, It was found that watershed lag, Lg, could also be expressed as {{{{Lg=0.247 { ( { LLca} over { SQRT { S} } )}^{ 0.604} }}}} in connection with the product of main stream length and the centroid length of the basin of the watershed area, LLca which could be expressed as a measure of the shape and the size of the watershed with the slopes except watershed area, A. But the latter showed a lower correlation than that of the former in the significance test. Therefore, it can be concluded that watershed lag, Lg, is more closely related with the such watersheds characteristics as watershed area and length of main stream in the small watersheds. Empirical formula for the peak discharge per unit area, qp, ㎥/sec/$\textrm{km}^2$, was derived as qp=10-0.389-0.0424Lg with a high significance, r=0.91. This indicates that the peak discharge per unit area of the unitgraph is in inverse proportion to the watershed lag time. 8. The base length of the unitgraph, Tb, in connection with the watershed lag, Lg, was extra.essed as {{{{ { T}_{ b} =1.14+0.564( { Lg} over {24 } )}}}} which has defined with a high significance. 9. For the derivation of IUH by applying linear conceptual model, the storage constant, K, with the length of main stream, L, and slopes, S, was adopted as {{{{K=0.1197( {L } over { SQRT {S } } )}}}} with a highly significant correlation coefficient, 0.90. Gamma function argument, N, derived with such watershed characteristics as watershed area, A, river length, L, centroid distance of the basin of the watershed area, Lca, and slopes, S, was found to be N=49.2 A1.481L-2.202 Lca-1.297 S-0.112 with a high significance having the F value, 4.83, through analysis of variance. 10. According to the linear conceptual model, Formular established in relation to the time distribution, Peak discharge and time to peak discharge for instantaneous Unit Hydrograph when unit effective rainfall of unitgraph and dimension of watershed area are applied as 10mm, and $\textrm{km}^2$ respectively are as follows; Time distribution of IUH {{{{u(0, t)= { 2.78A} over {K GAMMA (N) } { e}^{-t/k } { (t.K)}^{N-1 } }}}} (㎥/sec) Peak discharge of IUH {{{{ {u(0, t) }_{max } = { 2.78A} over {K GAMMA (N) } { e}^{-(N-1) } { (N-1)}^{N-1 } }}}} (㎥/sec) Time to peak discharge of IUH tp=(N-1)K (hrs) 11. Through mathematical analysis in the recession curve of Hydrograph, It was confirmed that empirical formula of Gamma function argument, N, had connection with recession constant, Kl, peak discharge, QP, and time to peak discharge, tp, as {{{{{ K'} over { { t}_{ p} } = { 1} over {N-1 } - { ln { t} over { { t}_{p } } } over {ln { Q} over { { Q}_{p } } } }}}} where {{{{K'= { 1} over { { lnK}_{1 } } }}}} 12. Linking the two, empirical formulars for storage constant, K, and Gamma function argument, N, into closer relations with each other, derivation of unit hydrograph for the ungaged small watersheds can be established by having formulars for the time distribution and peak discharge of IUH as follows. Time distribution of IUH u(0, t)=23.2 A L-1S1/2 F(N, K, t) (㎥/sec) where {{{{F(N, K, t)= { { e}^{-t/k } { (t/K)}^{N-1 } } over { GAMMA (N) } }}}} Peak discharge of IUH) u(0, t)max=23.2 A L-1S1/2 F(N) (㎥/sec) where {{{{F(N)= { { e}^{-(N-1) } { (N-1)}^{N-1 } } over { GAMMA (N) } }}}} 13. The base length of the Time-Area Diagram for the IUH was given by {{{{C=0.778 { ( { LLca} over { SQRT { S} } )}^{0.423 } }}}} with correlation coefficient, 0.85, which has an indication of the relations to the length of main stream, L, centroid distance of the basin of the watershed area, Lca, and slopes, S. 14. Relative errors in the peak discharge of the IUH by using linear conceptual model and IUH by routing showed to be 2.5 and 16.9 percent respectively to the peak of observed unitgraph. Therefore, it confirmed that the accuracy of IUH using linear conceptual model was approaching more closely to the observed unitgraph than that of the flood routing in the small watersheds.

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