• 한국컴퓨터정보학회논문지
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• 제14권4호
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• pp.69-76
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• 2009

인터넷을 구성하는 IP 기반의 네트워크 구성은 다양한 회사의 라우터와 스위치 장비들로 구성되어 있다. 다양한 장비의 구성은 웜, 바이러스, DDoS 등과 같은 유해트래픽을 필터링하기 위하여 각 회사마다 서로 다른 형태의 문자 명령어 기반인 CLI가 주로 사용되고 있어 관리 및 제어의 복잡성이 높다. 이의 대안으로 IETF에서는 XML 기반으로 구성관리 표준을 NETCONF 작업 그룹에서 제정하고 있지만, NETCONF의 명령어 처리 단계에서 처리되는 명령어 몇 가지만 표준으로 정의되어 있고, 유해트래픽을 차단하기 위한 XML 명령어는 각 회사 장비마다 서로 다르게 되어 있으므로 이 기종 장치간의 일관된 제어 명령어 처리가 어렵다. 본 논문에서는 이 기종 장치의 일관된 제어 명령어를 통하여 네트워크로 유입되는 유해트래픽을 싱크홀 라우터로 우회시키고, 유입된 트래픽을 대상으로 유해성 여부를 판단하여 다양한 공격을 효과적으로 차단할 수 있는 제어시스템을 설계하여, 유해트래픽으로 부터 보호되고, 보다 안정된 네트워크 효율을 높일 수 있는 방법을 제안하였다.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.397-402
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• 2013

In super-tall building construction projects, schedule risk factors which vertically change and are not found in the low and middle-rise building construction influence duration of a project by vertical attribute; and it makes hard to estimate activity or overall duration of a construction project. However, the existing duration estimating methods, that are based on quantity and productivity assuming activities of the same work item have the same risk and duration regardless of operation space, are not able to consider the schedule risk factors which change by the altitude of operation space. Therefore, in order to advance accuracy of duration estimation of super-tall building projects, the degree of changes of these risk factors according to altitude should be analyzed and incorporated into a duration estimating method. This research proposes a simulation model using Monte Carlo method for estimating activity duration incorporating schedule risk factors by weather conditions in a super-tall building. The research process is as follows. Firstly, the schedule risk factors in super-tall building are identified through literature and expert reviews, and occurrence of non-working days at high altitude by weather condition is identified as one of the critical schedule risk factors. Secondly, a calculating method of the vertical distributions of the weather factors such as temperature and wind speed is analyzed through literature reviews. Then, a probability distribution of the weather factors is developed using the weather database of the past decade. Thirdly, a simulation model and algorithms for estimating non-working days and duration of each activity is developed using Monte-Carlo method. Finally, sensitivity analysis and a case study are carried out for the validation of the proposed model.

• 한국지능시스템학회논문지
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• 제16권6호
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• pp.683-690
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• 2006

무선 센서 네트워크에서 에너지 소비의 효율성은 전체 네트워크 수명 시간을 결정하기 때문에 에너지 소비를 최소화하기 위한 연구가 활발히 진행되고 있다. 무선 센서 네트워크에서 에너지 보전을 위해서는 운영에 필요한 최소한 센서 노드만을 활성화된 상태로 유지하고 나머지 노드들은 휴면 상태로 유지하여 불필요한 에너지 소비가 일어나지 않도록 하여야 한다. 그러나 얼마만큼의 센서 노드들을 최적의 운영 노드 집합에 포함시킬 것인지를 계산하는 것은 NP-hard 문제로 알려져 있다. 본 논문에서는 최적에 근접한 커버 집합(cover set)을 생성하기 위하여 CVT 기반의 근사화 알고리즘을 제안하였다. 제안된 알고리즘에서는 센서의 통신 범위가 센싱 범위의 두 배 이상이면 커버 집합에 속한 센서 노드 간의 연결이 즉시 이루어지도록 하고 반면에 통신 범위가 센싱 범위의 두 배 이하이면 커버 집합의 접속성 보장을 위하여 보조 노드를 결정하는 연결 기법을 제시하였다. 마지막으로 제안된 알고리즘의 성능 평가를 위하여 이론적 분석과 실험을 수행하였으며, 실험결과를 통해 제안된 알고리즘이 Greedy 알고리즘보다 CCS(Connected Cover Set)의 크기와 실행 시간 측면에서 우수함을 보였다.

• 한국주조공학회지
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• 제20권5호
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• pp.330-335
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• 2000

Functional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported. But a system which can build directly 3D parts of high performance functional material as metal park would get long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we translated the wax patterns to numerous metal tool prototypes by new investment casting process combined conventional investment casting with rapid prototyping & rapid tooling process. With this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P pare to metal part.

• 수산경영론집
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• 제31권1호
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• pp.73-93
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• 2000

This study analyzed and mutually compared the fishery manpower problems in Northeast Asia region including Korea, China, Japan by fishery industry structure, fishery education, fishery manpower and presented fishery cooperative schemes of Northeast Asia. In case of fishery manpower problems, China is still in a better situation whereas Korea and Japan have a hard time of a labor shortage. Korean companies have employed foreign crews to find a way out of the difficulties and the foreign crew rate is growing but the problem is that the reduction of Korean crew could deteriorate the safety of vessel-sailing, efficient operations, and fishery efficiency. Therefore crew management should be placed focus on improvement of working conditions and guarantee positions to foreign crew as assistants in fishery surroundings and systems. Fishery manpower problems are complementary to each nation in Northeast Asia. In consideration of this fact, fishery manpower management needs the mutual fishery manpower and information exchange and for the sake of it, the most urgent task is to build up the international fishery cooperative network through establishing fishery-related information systems of Northeast Asia.

• 농촌의학ㆍ지역보건
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• 제22권1호
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• pp.75-83
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• 1997

The medical insurance system has been adopted in 1989. Since then, the utilization of medical care services has increased rapidly. It appears that the medical institution needs more nursing manpower such as nurses and nurse aides to meet an increased demand for medical care for the residents. However, the medical care clinics run by a medical practitioners has a more shortage of nursing manpower than hospitals. The purpose of this survey was to analyze the current employment status and to obtain an opinion on the improvement of utilization such as recruitment and retention of nursing manpower. The questionnaire sent to the private physician and the response rate was 28.7% ; 87 out of 300 physicians. 82.6% of the respondents employed nurses aides rather than nurses and an average number of employees per clinic was 2.5 persons. Most physicians had difficulties in recruiting nursing manpower. It took more than one month for replacement on average, therefore, they were suffering from giving good continual care for the patient and also high resignation of nursing personnel. The low wage, long working hours, hard work and lack of incentives are the biggest reasons for the difficulty in recruiting and retaining of the nursing personnel obtained for the clinics survey. The above mentioned problems would be solved in the near future by changing those difficulties. In the meantime, the private physicians are marking an effort to retain the nursing personnel by keeping a relationship of the private physician's cooperatives.

• 간호행정학회지
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• 제20권5호
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• pp.514-524
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• 2014

Purpose: The purpose of this study was to explore the experiences of clinical nurses over 40 years of age who were shift workers. Methods: Data were collected from in-depth interviews with 10 clinical nurses over 40 years of age who had at least 10 years of clinical experience and who worked in 5 acute care hospitals. The data were analyzed using Braun & Clark's thematic analysis. Results: One main theme, 3 themes, and 9 subthemes were derived. The main theme was "Sustaining a position still in conflict", and themes were as follows; "Being trained as a professional nurse", "Having unfavorable working conditions and damaged self-esteem", "Trying hard to get a sense of value as an experienced nurse" Conclusion: The results of this study show the issues of age and generational diversities in nurses in acute care hospitals. It is necessary to explore various ways to utilize the experience of older clinical nurses for the integrity of nursing organization and the development of the nursing profession.

• 한국주거학회논문집
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• 제23권2호
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• pp.79-87
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• 2012

The purpose of this study was to offer improvements, by deriving practical problems and suggesting ways to improve more realistic solutions in the multi-family housing management industry. This study is conducted in two ways. First, it was performed by reviewing related previous studies and clarifying major issues in the multi-family housing management. Second, it was performed by a questionnaire survey method, focused on the worker's opinions for that matters. The respondents work in an apartment in Seoul and the metropolitan area. A questionnaire distributed via e-mail, and then were collected. And questionnaire did not respond were excluded from the analysis. Finding were as follows -; first, it was possible to clarify four types regarding major issues in the multi-family housing management such as 'management system', 'housing management market conditions', 'management consciousness of resident', 'management performances'. Second, it was found that the competition was fierce in the same kind. And it was quite a high turnover rate of workers because of poor working conditions. Third, the most hard part was that the employee welfare was not good at work.

• 대한산업공학회지
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• 제34권1호
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• pp.49-56
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• 2008

Reliability has been considered as an important design measure in various industrial systems. We discuss a reliability optimization problem with component choices (ROP-CC) subject to a budget constraint. This problem has been known as a NP-hard problem in the reliability design fields. Several researchers have been working to find the optimal solution through different heuristic methods. In this paper, we describe our development of simulated annealing (SA) and tabu search (TS) algorithms and a reoptimization procedure of the two algorithms for solving the problem. Experimental results for some examples are shown to evaluate the performance of these methods. We compare the results with the solutions of a previous study which used ant system (AS) and the global optimal solution of each example obtained through an optimization package, CPLEX 9.1. The computational results indicate that the developed algorithms outperform the previous results.

• 산업공학
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• 제2권1호
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• pp.79-96
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• 1989

Abundant hard-working and well-educated human resources were the important sources of the spectacular economic success during the last decades. In contrast to the past sources of economic growth during the 1970's when labor and capital along with economies of scale were the dominant factors (the university has played an important role in the national economic success by supplying quality labour and intellectual talent.), the level of science, technological innovation and capital inputs will be of vital importance for future economic growth in Korea. The balance of payments in technology transfer together with the current state of R & D activities has been reviewed and some of the issues and problems underlying the university system that tend to hinder research in collaboration with research institutes and industries have been outlined. Serious imbalance in the allocation of research funds among research sectors was identified as the most serious problem to be fixed. The importance of science and technology education in private universities for the enhancement of the national level of science and technology has been re-examined. Also research and development in engineering and technical services has been emphasized. In conclusion, ways to bolster the role of universities in the research environment in cooperation with industry and research institutes have been suggested.