• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.156-161
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• 2001

Currently, agricultural facilities are evaluated using either basic inspections or detailed analysis. However, conventional analyses as well as methods based on fuzzy logic and rule of thumb have not been very successful in providing a clear relationship between rating and real state of agricultural facilities, because they can't provide exactly acceptable reliability of degraded structures with manager or supervisor. Therefore, in this stage, we must define probabilistic variables for representing degradation of structures being given damages during a survival time. This paper describes the application of neural network system in developing the relation between subjective ratings and parameters of agricultural reservoir as well as that between subjective and analytical ratings. It is shown that neural networks can be trained and used successfully in estimating a rating based on several parameters. The specific application problem for agricultural reservoir in the rural area of Korea is presented and database is constructed to maintain training data set, the information of inspection and facilities. This study showed that a successful training of a neural network could be useful, especially if the input data set for target problem contains parameters with a diverse combination of inter-correlation coefficients. And the networks had a prediction rating of about $^{\ast}^{\ast}^{\ast}%$. The neural network system is expected to show high performance fairly in estimate than statistical method to use equation that is consisted of very lowly interrelated variables.

• 정보와 통신
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• 제4권4호
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• pp.505-524
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• 1987

Nowaday all the countries of the world have studied the various problems caused in operating their own ports efficiently. Ship delay in the port is attributal to the inefficient operation in the navigation aids, the cargo handling, the storage and transfer facilities, and to the inefficient allocation of gangs or to a bad service for ships. Among these elements the allocation of gangs is the predominating factor in minimizing ship's turn round time. At present, in the case of Pusan Port. the labour union and stevedoring companies allocate gangs in every hatches of ships by a rule of thumb, just placing emphasis on minimizing ship's turn round time, without applying the principle of allocation during the cargo handling. Owing to this the efficiency of the cargo handling could not be expected to be maximized and this unsystematic operation result in supplying human resources of much unnecessary surplus gangs. Therefore in this paper the optimal size and allocation of gangs for minimizing the ship's turn round time is studied and formularized. For the determination of the priority for allocation the evaluation function, namely $F=PHi^{n}{\times}(W+H)$, can be obtained; where, PHI : Principal Hatch Index W : Total Cargo Weight represented in Gang-Shifts H : Total Number of Ship's hatches and also for the optimal size of gangs the average number of gang allocated per shift (Ng), namely Ng=W/PHI, is used. The proposed algorithm is applied to Pusan Port and its validity is verified.

• 정보학연구
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• 제5권3호
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• pp.169-179
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• 2002

국내시장과는 환경과 여건이 판이한 해외시장을 표적시장(target market)으로 하는 국제마케팅은 시장자체의 형태가 천차만별일 뿐만 아니라 그 시장을 형성하는 상황, 시장구조 등이 전혀 다르며 다이나믹하게 급변하고 있다. 이러한 시장을 유지, 확대, 개척한다는 것은 효율적인 교역촉진의 수행 없이는 매우 어렵다. 보다 진보적이고 마케팅 정보를 토대로 하여 보다 세분화되고 구체화된 마케팅믹스 전략을 수행하는 것이 궁극적 목표이다.

• 한국항해항만학회지
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• 제28권7호
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• pp.609-617
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• 2004

The total tug capacity needed for berthing/unberthing operations of a ship may vary depending on the ship's type, size, loading conditions, and environmental circumstances. Traditionally, total tug capacity is determined based on the local guidelines of port authorities or on the rule of thumb. However, the social demands for the enhancement of ship safety at harbor and the economical demands for the cost-effectiveness of tug usage makes it necessary for port authorities to develop more reasonable and detailed guidelines on tug usage which takes various conditions into account. In this paper, the method to estimate the optimum tug capacity of VLCC is suggested by considering various ship conditions such as its size, loading conditions, and environmental circumstances including wind, wave, tidal currents, and geographical characteristics of a terminal. This method is applied to the VLCC terminal located in Gwang-Yang harbor of Korea and the results are compared with the local guidelines of the harbor, which shows that there may be a room for the amendment of local guidelines on tug usage.

• 한국소음진동공학회논문집
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• 제12권4호
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• pp.302-309
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• 2002

A FRF-based substructuring method attempts to predict the dynamic characteristics of a complex structure from predetermined FRFs of the comprising uncoupled substructures. Although this method has the advantage of being able to incorporate experimental component FRFs directly, it is prone to errors : measurement errors, coordinate incompleteness, modal incompleteness, etc. Among the various sources of errors, this paper deals with the problem of modal incompleteness (or residual problem) of which importance is underestimated compared to others. It is a well-known rule of thumb that such a problem can be overcome by including modes up to 2 or 3 times the upper frequency of interest. Using a simulated case study, it is demonstrated that even including modes up to 20 times the upper frequency of interest does not guarantee a satisfactory result. A method to compensate the residual errors is introduced. This method requires the whole FRF matrices of substructures which is practically impossible for a complex structure. An applicable alternative is suggested and applied successfully to the case study. Finally, the effects of measurement errors on the residual compensation are also discussed.

• 대한조선학회논문집
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• 제36권3호
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• pp.115-121
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• 1999

선박의 사고는 인명과 재산의 손실뿐만 아니라 사고 선박으로부터 유출되는 기름과 유해한 산적 화물에 의한 환경 오염을 초래하기 때문에 사고를 미연에 방지하는 것 뿐 만 아니라, 사고가 발생하였을 때 이에 신속히 대처함으로써 오명을 최소화하고 2차 사고의 위험을 줄이는 것이 매우 중요한 문제이다. 그러나 지금까지의 기술적 지원이 결여된 경험위주의 대처 방법으로는 사고선박에 대한 구난을 안전하고 신속하게 처리하기가 쉽지 않다. 본 연구에서는 체계적이고 과학적인 구난지원 도구를 개발하여 이를 사고 현장의 구난지원 작업에 투입하고자 한다. 이를 위하여 구난지원 체계를 구축하고, 프로토타입 시스템을 개발하여 사고선박에 대한 안전하고 신속한 구난지원 가능성을 검토하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.428-435
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• 2011

In general, thickness of the sublayers under track is designed based on concept of vertical soil reaction value or vertical stiffness. However, this design method cannot take consideration into soil-track interaction under repetitive load, traffic condition and velocity of the train. Furthermore, the reinforced roadbed soils experience complex behavior that cannot be explained by conventional stress-strain relation expressed as soil reaction value k. The reinforced roadbed soils also can produce cumulative permanent deformation under repetitive load caused by train. Therefore new design method for the sublayers under track must be developed that can consider both elastic modulus and permanent deformation. In this study, a new design concept, a rule-of-thumb, is proposed as the form of design monograph that is developed using elastic multi-layer and finite element programs by analyzing stress and deformation in the sublayers with changing the thickness and elastic modulus of the sublayers and also using data obtained from repetitive triaxial test. This new design concept can be applied to design of the reinforced roadbed before developing full version of design methodology that can consider MGT, axial load and the material properties of the layers. The new design monograph allows the user to design the thickness of the reinforced roadbed based on permanent deformation, elastic modulus and MGT.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 추계학술대회
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• pp.187-188
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• 2009

본 연구에서는 비선형예측기법으로서 현재 많은 관심을 받고 있는 인공신경망을 사용하여 컨테이너 물동량 예측을 수행하여 ARIMA모형과 비교하였다. 인공신경망의 예측성과에 많은 영향을 주는 네트워크 구조설계에 있어 기존의 선행연구들은 경험에 바탕을 둔 방법론을 사용하였다. 하지만 본 연구에서 그 대안으로 구조설계 문제에 있어 방대하며 복잡한 탐색공간에서 효과적으로 알려진 유전알고리즘을 사용하였다.

• Membrane and Water Treatment
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• 제3권4호
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• pp.253-266
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• 2012

In this work, the effect of hybrid salts precipitation-nanofiltration (SP-NF) process on the scale deposits in thermal and membrane desalination processes has been studied. The analysis was carried out to study the scale formation from the Arabian Gulf seawater in MSF and RO reference processes by changing the percentage of pretreatment from 0 to 100%. Four different SP-NF configurations were suggested. A targeted Top Brine Temperature (TBT) of $130^{\circ}C$ may be achieved if 30% portion is pretreated by SP and/or NF processes. As a rule of thumb, each 1% pretreatment portion increases the reference TBT of $115^{\circ}C$ by $0.6^{\circ}C$. For both MSF and RO, parallel pretreatment of certain percentage of the feed by SP and the rest by NF, showed the lowest scale values. The case showed the best values for sulfate scale prevention and the highest values of increasing the monovalent ions relative to the divalent scale forming ions. Sulfate scale is significant in MSF process while carbonate scale is significant in RO. Salt precipitation was suggested because it is less costly than nanofiltration, but nanofiltration was used here because it is efficient in sulfate ions removal.

• 터널과지하공간
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• 제11권4호
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• pp.328-338
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• 2001

Fiber Glass Tube(FGT) 또는 steel pipe를 이용한 터널막장의 수평보강공법 그리고 강관다단공법 등은 터널 굴착시 터널막장의 안정성이 확보되지 못할 경우에 흔히 사용된다. 그러나 이러한 공법이 사용된 터널의 역학적 거동은 아직 충분히 알려진 바가 없으며, 따라서 설계와 전산해석 과정에서 경험에 의존하는 경우가 많고 공법의 합리적인 적용이 어려운 실정이다. 본 연구에서는 복합체 역학을 이용한 보강공법의 전산해석 단순화 방법의 적용성을 검증하였고, 강화지반의 등가탄성계수는 평균장 이론과 변형률 에너지 이론을 사용하여 도출하였다. 다양한 보강패턴에 따른 터널막장의 거동에 관한 매개변수 연구를 수행하였다.