• 농업과학연구
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• 제38권3호
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• pp.513-524
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• 2011

To evaluate the applicability of inflow runoff model to reservoir operation in Korea, DAWAST model and TPHM model which are conceptual lumped daily runoff model and were developed in Korea, were selected and applied to simulate inflows to Daecheong multipurpose dam with watershed area of 4,134 $km^2$, and water storages in Geryong reservoir with watershed area of 15.1 $km^2$ and total water storage of 3.4 M $m^3$. Evaluating inflows on an yearly, monthly, ten-day, and daily basis, inflows by DAWAST model showed balanced scatters around equal value line. But inflow by TPHM model showed high in high flows. Annual mean water balance by DAWAST model was rainfall of 1,159.9 mm, evapotranspiration of 622.1 mm, and inflow of 644.6 mm, from which rainfall was 104.8 mm less than sum of evapotranspiration and inflow, and showed unbalanced result. Water balance by TPHM model showed satisfactory result. Reservoir water storages were shown to simulate on a considerable level from applying DAWAST and TPHM models to simulate inflows to Geryong reservoir. But it was concluded to be needed to improve DAWAST and TPHM model together from imbalance of water balance and low estimation in high flow.

• Journal of Advanced Marine Engineering and Technology
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• 제22권2호
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• pp.146-173
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• 1998

It is one of the most important factors Seafarers Education Quality Assurance and management in Higher Maritime Education Institution. The educational process and result of Higher Maritime Educational Institution. The educational process and result of Higher Maritime Educational Institution should be evaluated according to the 1995 Amendments to the International Convention on Standards of Training Certification and Watchkddping for Seafares(STCW) 1978. Actuall above-mentioned evaluation is deemed to make foundation in order to enhance the efficiency of shipboard education by surveying the satisfaction of shipboard training for Marine Engineering part cadets by the group. In this paper we carried out the questionnaire survey to study stisfactory value and the reason of dissatisfaction of 89 cadets being trained on board the Training Ship in Maritime College of Korea Maritime University The results were calculated by frequency and percentage; the significance of difference among Department groups like Marine Engineering Maritime polic and Ship Operating Systems Engineering Engineering was analysed by $x^2$ inspection.

• 한국생산제조학회지
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• 제21권3호
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• pp.433-438
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• 2012

We have studied on welding dissimilar materials of Carbon steel SCP1-S by using laser beam. In this research we have performed some experiments to know the possibility of welding dissimilar materials using laser beam and magnetic fields by adjusting the power output of 35W laser. Other conditions of the experiments were as follows : the welding speed was varied in the range 10 m/min nitrogen gas was used as shield gas, the flow value of shield gas was ranged 10 L/min. In order to ascertain of the welded surface, we have done the tensile strength testing, the hardness testing and the microscope observation. As a result, we have found that tensile strength was the highest at the condition of the welding speed of 10mm/s, the flow value of 10 L/min, the gap of two materials 0, and the use of nitrogen gas. Above testings have also showed that the tensile strength was generally satisfactory since the penetration of welding was almost complete due to the thinness of the materials. In addition, the formation of the welded area was excellent when it had the highest tensile strength.

• Journal of Communications and Networks
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• 제17권5호
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• pp.491-498
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• 2015

Recognition of radar emitter signals is one of core elements in radar reconnaissance systems. A novel method based on singular value decomposition (SVD) and the main ridge slice of ambiguity function (AF) is presented for attaining a higher correct recognition rate of radar emitter signals in case of low signal-to-noise ratio. This method calculates the AF of the sorted signal and ascertains the main ridge slice envelope. To improve the recognition performance, SVD is employed to eliminate the influence of noise on the main ridge slice envelope. The rotation angle and symmetric Holder coefficients of the main ridge slice envelope are extracted as the elements of the feature vector. And kernel fuzzy c-means clustering is adopted to analyze the feature vector and classify different types of radar signals. Simulation results indicate that the feature vector extracted by the proposed method has satisfactory aggregation within class, separability between classes, and stability. Compared to existing methods, the proposed feature recognition method can achieve a higher correct recognition rate.

• Journal of the Korean Wood Science and Technology
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• 제20권2호
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• pp.43-50
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• 1992

This study was carried out to investgate the possiblity of using waste bamboo and bast fiber from paper mulberry for Hwaseonji production. 3 types of Hwaseonji were made in an experimental system, 100% bamboo pulp, bamboo pulp mixed with bast fiber in two different ratios, 70% : 30% and 40% : 60%, respectively. The result were as follows: 1. The chinese ink blots of Hwaseonji made from bamboo pulp only was satisfactory, but its tensile strength showed a low value. In order to improve the tensile strength, we must develope a new beating method with musilige. 2. The burst strength increased as the bast fiber content increased. But it is a special characteristic of Hwaseonji, that an even formation of paper is required. Therefore, only the short bast fiber is needed. 3. The tensile strength was raised by increasing the bast fiber content to 60%, resulting in a more durable Hwaseonji. 4. In even thickness, the higher opacity showed the more bast fiber. So the opacity of product III (bamboo: 40%, bast fiber: 60%) is the highest. 5. The commodity value of hand-made paper should be grade-up after a dedusting process.

• 한국지능시스템학회논문지
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• 제17권7호
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• pp.964-969
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• 2007

본 논문은 원본 영상과 은닉 영상의 좋은 압축률과 만족할만한 이미지의 질, 그리고 외부공격에 강인한 영상 은닉의 한 방법을 제안한다. 이 워터마킹 방법은 특이치 분해와 퍼지 군집화 기반 벡터양자화를 이용한다. 실험에서는 은닉된 영상의 비가시성과 외부공격에 대한 강인성을 증명하였다. 이 워터마킹기법의 장점은 워터마크된 영상이 이미 압축되어 있으므로 압축과정과 동시에 저작권 보호에 이용할 수 있다는 장점이 있다.

• 한국항해항만학회지
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• 제26권2호
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• pp.161-166
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• 2002

컨테이너 처리량(CHC)은 항만의 능력을 나타내는 중요한 지표다. 그러나 중국항만의 컨테이너 처리능력에 대한 연구는 부족하며, 연구결과 또한 예측치와 실제치와의 차이가 크다. 이는 컨테이너처리량이 다양한 경제적인 측면을 내포하고 있고 예측모델의 선택이 매우 어렵다는데 기인한다. 대체로 지금까지 사용되어왔던 회귀분석, 신경망분석 등은 과거행태모델을 벗어나지 못하고 있어 경제체제나 항만물동량의 동태적변화에 대한 고려가 결여되어 있다. 따라서 본 논문에서는 동태적 보정인과모델을 사용한 동태적 예측법을 사용해 보았고 그 결과 보다 신뢰성이 높고 현실성이 있는 연구결과를 도출할 수 있었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.399-400
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• 2012

The proposed battery charger presented in this paper is suitable for Lead-Acid Battery and the dc/dc buck converter topology is applied as a charger circuit. The technique adopted in this charger is constant current & constant voltage dual mode, which is decided by the value of voltage of proposed battery. Automatic mode change function is detected by the percentage value of level of battery charging. CC Mode (Constant Current Mode) is operated when charging level is below 80% of the total charging of Battery voltage and above 80% of battery voltage charging, CV Mode (Constant Voltage Mode) is automatically operated. As the charging level exceeds 120%, it automatically terminates charging. The feedback signal to the PWM generator for charging the battery is controlled by using the current and voltage measurement circuits simultaneously. This technique will degrade the damage of proposed type of battery and improve the power efficiency of charger. Finally, a prototype charger circuit designed for a 12-V 7-Ah lead acid battery is constructed and tested to confirm the theoretical predictions. Satisfactory performance is obtained from simulation and the experimental results.

• Natural Product Sciences
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• 제22권1호
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• pp.20-24
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• 2016

Pentacyclic triterpenes, mainly, asiatic acid, madecassic acid, asiaticoside, and madecassoside are the active constituents of Centella asiatica. A pentacyclic triterpene enriched C. asiatica extract (PRE) was prepared and standardized to contain a total pentacyclic triterpenes not less than 65% w/w. This work was focused on determination of antiinflammatory, antioxidant, and tyrosinase inhibitory activities of PRE and its stability. The PRE exhibited a satisfactory nitric oxide inhibitory effect, with an $IC_{50}$ value of $64.6{\mu}g/mL$. In addition, the PRE inhibited tyrosinase enzyme activity with an $IC_{50}$ value of $104.8{\mu}g/mL$. In contrast, the PRE possessed only weak antioxidant activity. The PRE was stable over a period of four months when stored as a dried powder but only in a well-closed container protected from light at $4^{\circ}C$. An aqueous alcoholic solution of the PRE was stable at pH values of 5.8 and 7.0, but was not stable at a pH of 8.2. Preparations of the PRE in an aqueous solution should be performed in acidic or neutral conditions.

• Journal of Nutrition and Health
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• 제17권2호
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• pp.137-144
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• 1984

Due to the fact that blood gathering is not readily accepted by people, it has been difficult to make a full-scale study on zinc through blood analysis. For that reason, in this paper, a correlation of zinc contents in serum and hair was studied to find out whether only hair, which is relatively easy to collect, can be used for a measurement of zinc content. The subjects were 47 healthy female collegians selected at random whose average age was 22, mean height 159.1cm and average weight 49.7kg. The mean zinc value in serum of subjects was ${107.1}\pm{29.0}{\mu}g{/100ml}$, while the mean value in hair was ${150.2}\pm{42.7}ppm$. Correlation analysis shows that there was a significant correlation in zinc contents of serum and hair ( p<0.01). The results shows that measuring zinc level by using only hair samples would be satisfactory. But the use of hair sample for a measurement of zinc level has one demerit. That is, the method is more likely to be subjected to contamination because it makes more complicated procedures in sample preparation than the method of using blood sample.