• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.2
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• pp.250-260
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• 1993

Packet Reservation Multiple Access(PRMA) protocol provides a very efficient mechanism for many number of voice and data terminals with bursty traffic characteristics to share efficiently a common transmission channel. This protocol, however, cannot operate in high load conditions. That is, there occurs a instability problem, since the reservation channel is allowed to shrink to zero. In this paper, a more stable PRMA protocol which can avoid such problems and integrates voice and data traffic efficiently is proposed. Also, the performance of the proposed protocol is analyzed by a computer simulation. According to the simulation results, it can be shown that the proposed protocol provides a more efficient mechanism for voice/data integration and ensures a more stable operation than conventional PRMA protocol in high load conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.746-749
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• 2015

The purpose of this study is to investigate the source of competitive advantage to create a successful business model. in IT firm. Business Model is strategic management tool to successful marketplace entry. This study provide that how business model works and what elements is important. When developing a business model framework and hoe they structure relationship between the proposed framework from product or service point of view. Business model must use a various platform as a online.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.951-969
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• 2010

A Study on the Management Performance of the Distribution channel's CRM : Balanced Scorecard Approach as to CRM application field of the Distribution Company About Korea Airport Service In this paper, the performances of Distribution channel's estimation schemes for CRM system are investigated. We anticipate these moves will have a positive effect on the CRM Scorecard infra, process, elevate royalty environments. As is study of used SPSSWN 15.0 correlation analysis, regression analysis & AMOS 7.

• Asia Marketing Journal
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• v.7 no.2
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• pp.123-139
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• 2005

Until now, There are many studies of reward program effect about retaining current customers. But main goal of this study is acquiring new customer in competitive environment. We also reveal strategic framework for maximizing acquisition of new customer. For increasing customer loyalty of non-use brand, we'd better to give Out My Own reward non-user immediately and for increasing customer loyalty of use brand we'd better to give In My own Brand user accumulatively. Implication of the results for markets and future research are discussed

• Korean Journal of Construction Engineering and Management
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• v.17 no.3
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• pp.61-70
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• 2016

Construction enterprises have performed various projects such as buildings, infrastructure and plant projects in the international market. Among these, the plant project's amount of orders accounted for about 68.9% of all. However, because of the enterprises won a contract with a low-budget for plant project in the last 10 years, the profit has dropped dramatically. And it is forecasted that there are extreme competition for bid award of plant projects because of the current falling oil prices and raising interest rates. In this circumstance, the comprehending of enterprises strength and weakness must be a priority to get a sustainable competitive advantage. Therefore this research suggests the enterprises's capability assessment framework and it is in order to diagnose the korean construction enterprises capabilities. The framework is based on the VRIO model that is on the basis of resource based theory. First, the capability assessment indices and their importance and priority that based on the life-cycle of plant project is deducted by literature review and survey. Second, the 5 point likert score applied VRIO survey is conducted to diagnose the enterprises and quantified the survey result using the fuzzy theory. Lastly, the competitvie implication and capability assessment are deducted.

• The Korean Journal of Financial Management
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• v.8 no.2
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• pp.209-255
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• 1991

This paper develops a simple model to explain the reasons why foreign acquirers pay significantly higher premiums for U.S. target firms than do U.S. buyers. We also provide empirical work on the valuation effect of foreign takeovers and the determinants of the wealth gains of U.S. target shareholders involved in foreign takeovers. The results indicate that target wealth gains are significantly higher in foreign takeovers than in domestic takeovers, after controlling for the wealth effects of payment method, acquisition type, tax status, size and time period of bids. This confirms the valuation effect of foreign takeovers. Furthermore, the results of cross-sectional regression analysis show that the variation in U.S. target wealth gains is explained by extra tax benefits stemming from double tax deductions for acquisition-related interest expenses incurred by foreign acquirers. These findings imply that differential taxation across tax jurisdictions is the main source of the valuation effect of foreign takeovers. In addition, we find that there exists a valuation effect of the nationality of the foreign acquirers. Japanese companies pay significantly higher premiums than do non-Japanese acquirers. The finding also indicates that competition among bidders increases the abnormal returns to U.S. target shareholders in foreign takeovers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.42-48
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• 2002

In broadband wireless networks, the effective meeting of the QoS guarantees may strongly depend on the Contention Resolution Algorithm used in the uplink contention period. The time it takes a station to transmit a successful request to the base station, or request delay, must be kept low even during periods of high contention. If a request suffers many collisions, it cannot rely on the preemptive scheduler to receive low access delays. However, the conventional collision resolution algorithm has a problem that all collided stations are treated equally regardless of their delay from previous contention periods. Some requests may have very long request delay caused by continuous collisions. In this paper, we propose an adaptive collision resolution algorithm for fast random access in broadband wireless networks. The design goal is to provide quick access to the request with a high number of collisions. To do this, the proposed algorithm separates the whole contention region into multiple sub regions and permits access through each sub region only to the requests with equal number of collisions. The sub region is adaptively created according to the feedback information of previous random access. By simulation, the proposed algorithm can improve the performance in terms of throughput, random delay and complementary distribution of random delay by its ability to isolate higher priorities from lower ones. We can notice the algorithm provides efficiency and random access delay in random access environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.104-104
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• 2011

2010년 기준 세계 물산업은 약 4,800억불 규모이며, 2025년에는 약 1조 달러 규모로 성장할 것으로 전망된다. 또한 기후변화 등의 요인으로 물산업의 범위는 물순환체계 전과정을 포괄하는 "유역종합개발+상하수도+대체수자원"으로 확장될 것으로 예측된다. 그러나 지금까지의 국내 물산업 육성은 주로 상하수도 분야 중심으로 국한되어, 기후변화에 대응한 유역종합개발 분야에 대한 시장 진출기회를 상실하고 있다. 상하수도 중심의 물산업은 이미 선진 메이저 기업들이 선점하여 치열한 경쟁이 벌어지고 있는 '레드오션'이라 할 수 있으므로, 새로운 물산업의 강국으로 부상하기 위해서는 우리가 가진 장점을 바탕으로 물산업의 새로운 영역을 개척하는 방안에 대한 연구가 필요한 시점이다. 본 연구는 먼저 국내외 물순환체계 전과정(유역종합개발+상하수도+대체수자원)에 대한 시장 조사을 통해 세계 물산업 시장을 프로젝트 유형별, 지역별로 분석하고, 이를 토대로 국내 물산업 육성과 해외진출을 위한 당면 과제를 다음과 같이 제시하였다. 첫째, 민관협력을 위한 제도적 틀을 형성할 필요가 있다. 정부의 역할이 매우 중요한데, 정부 또는 기금이 자금의 단순한 대부자에서 적극적인 투자자로 전환함으로서 국내 민간기업들의 해외시장 진입장벽을 낮추어 줄 필요가 있다. 정부 주도의 민관협력이 활성화되면 참여 기업의 재무적 리스크를 현저히 줄일 수 있다. 또한, 상하수도 운영 경험을 축적한 공기업이 해외진출 지원기능을 수행하도록 하여야 한다. 즉, 공기업이 민간 기업의 경쟁자가 아니라 지원자가 될 수 있도록 프레임을 바꿔주어야 한다. 둘째, 물산업 클러스터의 형성이다. 물산업 제조업은 대부분 중소 벤처기업으로 독자적인 해외진출이 곤란하므로, 물전문 공기업이 중소 벤처기업 육성 및 해외진출의 앵커 역할을 담당하는 것이 필요하다. 이스라엘이나 싱가포르의 물산업 클러스터처럼 Anchor 역할을 행하는 공기업과 민간기업이 장기적 협력관계를 구축할 수 있는 기반을 마련해야한다. 셋째, 신시장 역량의 창출이다. 기후변화로 크게 성장할 전망인 통합물관리 시장에 대한 전략적 접근이 요구된다. 우선 ODA 등 대외 원조자금을 활용하여 투자비가 적게 들고 정보를 선점할 수 있는 조사 설계부터 시작하여, 댐 및 수력개발, 상하수도 건설 운영 등에 단계적으로 접근할 수 있을 것이다. 또한, 향후 도입될 예정인 물인프라의 Smart 기술, 첨단 수처리 기술 등을 활용하여 새로운 시장을 개척해야 한다. 4대강살리기 사업, 해수담수화 등 조기에 경쟁우위를 갖출 수 있는 사업과 기술을 Flagship Project로 브랜드화하여 우리나라를 "물강국"으로 포지셔닝할 경우 세계 물시장 공략에 보다 효과적일 것으로 판단된다.

• The Korean Journal of Applied Statistics
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• v.30 no.4
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• pp.539-553
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• 2017

We propose a multi-state model to analyze semi-competing risks data with interval-censored or missing intermediate events. This model is an extension of the three states of the illness-death model: healthy, disease, and dead. The 'diseased' state can be considered as the intermediate event. Two more states are added into the illness-death model to incorporate the missing events, which are caused by a loss of follow-up before the end of a study. One of them is a state of the lost-to-follow-up (LTF), and the other is an unobservable state that represents an intermediate event experienced after the occurrence of LTF. Given covariates, we employ the Lin and Ying additive hazards model with log-normal frailty and construct a conditional likelihood to estimate transition intensities between states in the multi-state model. A marginalization of the full likelihood is completed using adaptive importance sampling, and the optimal solution of the regression parameters is achieved through an iterative quasi-Newton algorithm. Simulation studies are performed to investigate the finite-sample performance of the proposed estimation method in terms of empirical coverage probability of true regression parameters. Our proposed method is also illustrated with a dataset adapted from Helmer et al. (2001).

• Journal of Science and Technology Studies
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• v.1 no.2 s.2
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• pp.291-309
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• 2001

Let us critique the common notion that ethical examination retards the development of science and technology. First, I shall reformulate such a notion in the following statements: 'To survive the competitive society, we must develop science and technology before others do. It will cost too much time to examine ethically the influence of developing science and technology. Therefore, we cannot but suspend the ethical matters until we have developed science and technology.' I will then show that even if we reconstruct the above argument in a deductively valid form, the second premise is not necessarily true and that we cannot accept the conclusion because the meaning of 'competing for better lives', in the first premise, is diverse. Especially if we are to take into account all the areas of ethics and base them upon the autonomous ethics of democratic societies, it cannot be concluded that ethics is an enemy of developing science and technology. In addition, I will argue that our moral considerations must be based upon autonomous ethics in order to make the development of science and technology contribute to enhancing the desirable science culture. In the midst of making the above argument, it is proposed that the title of the 1aw of bio-ethics be changed, for it has a mistaken implication that acting against ethics results in legal punishments.