• JSTS:Journal of Semiconductor Technology and Science
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• 제8권2호
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• pp.115-120
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• 2008

Carrier velocity in the MOSFET channel is the main driving force for improved transistor performance with scaling. We report measurements of the drift velocity of electrons and holes in silicon inversion layers. A technique for extracting effective carrier velocity which is a more accurate extraction method based on the actual inversion charge measurement is used. This method gives more accurate result over the whole range of $V_{ds}$, because it does not assume a linear approximation to obtain the inversion charge and it does not limit the range of applicable $V_{ds}$. For a very short channel length device, the electron velocity overshoot is observed at room temperature in 37 nm MOSFETs while no hole velocity overshoot is observed down to 36 nm. The electron velocity of short channel device was found to be strongly dependent on the longitudinal field.

• 대한조선학회논문집
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• 제53권4호
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• pp.336-342
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• 2016

H-CSR(Harmonized Common Structural Rules) integrating CSR-BC(Common Structural Rules for Bulk Carriers) and CSR-OT(Common Structural Rules for Double Hull Oil Tankers) came into effect in July of 2015, so that bulk carrier and double hull oil tanker should comply with this rules. So far, several studies for trend analysis of requirements of structure scantling based on H-CSR have been carried out briskly. However, those studies are rare to apply H-CSR in actual structural design of ships, especially bulk carriers. In this study, an automated system for compartment arrangement is used to search the design case that minimizes still water bending moment(S.W.B.M) in 38k bulk carrier designed by Far East Ship Design & Engineering Co. Ltd. Also, various structural design cases are considered by changing arrangement of structural members to reduce ship weight. The SeaTrust-Hullscan software developed by Korean Register is used to perform structural design of ships based on mother ship and proper design cases are selected by user. The DSA(Direct Strength Analysis) is performed to evaluate structural safety for the yielding and buckling analysis by using MSC Nastran software. The effect of weight reduction is verified by comparison of ship weight between mother ship and the selected design cases.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.237-238
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• 2006

Vibration incidents hardly happen when a turbine generator usually installed in LNG carrier is operated, different from diesel engine generator. The purpose of this paper is to introduce an actual vibration incident, which hardly occurred in case of turbine generator, and describe all possible countermeasures to prevent from vibrations during operation.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.97-99
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• 2006

A ship owner has been disappointed with the wrinkle, phenomenon visually occurring at the side shell structure of VLCC(very large crude oil carrier). In order to solve this problem, we have firstly performed a variety of actual measurements. Furthermore, comparing the welding deformation level of DSME(Daewoo Shipbuilding & Marine Engineering Co. Ltd.) with that of SHI(Samsung Heavy Industries), the superiority of deformation control level of Korean shipyard has been substantiated.

• 전자공학회논문지A
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• 제28A권5호
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• pp.339-346
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• 1991

In this paper the performance of communication system in the electrical power line using error correcting codes is analysed. The BCH codes and interleaved code are to be used for correcting burst and random errors in the power line channels. The data rate of 2400 bps and the carrier frequency of 12KHz are assumed. Actual power line noise is recorded and simulated in the BPSK PLC system model.

• Journal of Positioning, Navigation, and Timing
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• 제8권2호
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• pp.41-47
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• 2019

Recently, number of intentional jamming has increased significantly. If GNSS jammers are activated, user receivers can be largely influenced due to the vulnerable characteristic of the GNSS (Global Navigation Satellite System) signal. When the reception power of the jamming signal and that of the navigation signal are similar, the C/A (Coarse Acquisition) chip delay error can occur in the delay locked loop. To evaluate the jamming effect, a new measurement model is formulated based on previous research works. The new model explains how the jamming to signal ratio affects the ranging measurement accuracy and other parameters. To evaluate the validity of the newly formulated model, the experiment results of the previous research works under actual jamming environment are utilized. By evaluating the consistency of the carrier-to-noise ratio (C/N0) and the position error with the actual jamming environment, the validity of the newly formulated model is verified.

• 한국해양공학회지
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• 제11권2호
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• pp.100-106
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• 1997

Viscous flow around an actual ship is calculated by an use of RANS(Reynolds-averaged Navier-Stokes) solver. Reynolds stress is modelled by using k-$\varepsilon$ turbulence model and the law of wall is applied near the body. Body fitted coordinates are introduced for the treatment of the complex boundary of the ship hull form. The transformed equations in the computational domain are numerically solved by an employment of FVM(Finite Volume Method). SIMPLE(Semi-Implcit Pressure Linked Equation) method is adopted in the calculation of pressure and the solution of the disssssssscretized equation is obtained by the line-by-line method with the use of TDMA(Tri-Diagonal Matrix Algorithme). The subject ship model of actual calculation is 4,410 TEU class container carrier. For 4 geosim models the calculated viscous resistancce values are compared with the model test results and analyzed on their componentss. The resistance performance of an actual ship is predicted very resonably, so this mothod may be utilized as a design tool of hull form.

• 항공우주정책ㆍ법학회지
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• 제21권2호
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• pp.71-96
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• 2006

본고에서는 국제항공화물운송에 있어서 운송인의 화물의 인도의무와 불법인도에 대한 책임에 관하여 몬트리올 협약, lATA 화물운송약관 및 법원판례를 중심으로 고찰하고자 한다. 몬트리올 협약 제13조에 의하면, 수하인은 화물이 도착지에 도착하였을 때에 운송인에 대하여 채무액을 지급하고 운송의 조건에 따랐을 경우에는 자기에게 화물의 인도를 요구할 수 있는 권리를 가지게 된다. 한편 운송인은 별도의 약정이 없는 한 화물이 도착하자마자 수하인에게 통지를 하여줄 의무가 있다. 몬트리올 협약 제18조에 의하면, 운송인은 화물의 파괴, 분실 또는 훼손으로 인하여 입은 손실에 대하여 그 손해의 원인이 되었던 사실이 항공운송 중에 발생되었다는 것을 유일한 조건으로 하여 책임을 부담하게 된다. 여기서 항공운송이라 함은 그 화물이 운송인의 보관하에 있는 기간을 포함한다. lATA 화물운송약관 제11조에 의하면, 운송인은 화물의 운송 중에 파괴, 멸실, 손상 또는 지연의 경우 입은 손해에 대하여 오직 그렇게 입은 손해의 원인된 사고가 제1조에 정의된 운송 중에 발생한 경우에만 송하인, 수하인 또는 기타인에게 책임을 진다. 여기서 운송이라함은 무상이든 또는 보수를 위한 것이든 간에 항공 또는 기타 운송수단에 의한 화물의 운송을 의미한다. 우리 대법원 판례(2004. 7. 22 선고)에 의하면, 운송인으로서 운송주선인은 보세창고에 입고된 화물이 실수입자에게 불법 인도된 경우에 보세창고를 지정한 자는 운송주선인 이나 그의 운송대리점이 아니라 실수입자이며, 운송주선인은 보세창고업자에 대하여 사용자로서의 지위에 있다고 볼 수 없으므로 보세창고업자의 화물의 무단반출에 대하여 손해배상책임을 지지 아니한다고 판시하였다. 결론적으로 운송인 또는 운송주선인이 항공화물의 불법인도로 인한 손해배상책임을 부담하지 않기 위하여는 항상 회물의 동향이나 상태에 대하여 주의를 기울여 화물이 불법인도 되지 않도록 선량한 관리자로서의 주의를 다하여야 할 것이다. 한편 우리 정부는 이미 발효된 몬트리올 협약에 가입하여 국제항공화물운송인의 권리, 의무 및 책임에 관하여 몬트리올 협약이 적용되도록 하여야 할 것이다.

• 한국항해학회지
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• 제18권2호
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• pp.19-40
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• 1994

Several factors can be chosen for evaluating seakeeping performance, such as deck wetness, propeller racing, slamming, rolling, vertical acceleration and vertical bending moment, in consi-deration of the safety of human being, cargo and ship. In fact, there are few developments for an evalua-tion method of seakeepting performance correponding with each ship's characteristics. The purpose of this paper is to develop an quantitative evaluation method of seakeeping performance according to ship types. The scope and the method of this study are as follow. (1) Obtain each response amplitude of ship's motion in waves by Ordinary Strip Method and apply it to short-crested, irregular wave for random process of the factors on seakeeping performance. (2) Define the evaluation index, the dangerousness, the maximum dangerousness and the evaluation diagram. (3) Figure out the different characteristics according to ship types by computer simulation of evaluating seakeeping performance. (4) Adopt vertical acceleration and one of rolling or lateral acceleration as the factors on seakeeping performance by clarifying the correlation of stochastic process. This study developed an evaluation method coincident with each ship's characteristics, and suggested a device for application to actual ship. This method might be useful in developing the practical system of seakeeping performance in accordance with ship types. The ship models for computer simulation are 175m container ship types, 93m tranning ship HANARA as passenger ship type, 259m bulk-carrier type and 164m pure car-carrier type.

• 대한조선학회논문집
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• 제58권3호
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• pp.144-157
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• 2021

Brake Horse Power (BHP) reduction ratios by air injection to the underside of the hull surface in an actual ship are predicted using an unstructured finite-volume CFD solver and compared with the sea trial results. In addition, air lubrication system installed on the existing vessel is investigated to find a good solution for additional drag reduction. As a results, it is found that the thickness of the air layer should be minimized within a stable range while securing the area covered by the air layer as much as possible. Furthermore, the amount of frictional drag reduced by air injection is found to be independent of surface roughness and still effective on rough surface. Based on the results of this study, it is expected that systematic and reliable air lubrication system can be designed and evaluated using the proposed method.