대형 LNG 선박의 선체 운동은 선박의 안전에 영향을 미친다. 본 연구의 목적은 153,000 m3 급 대형 LNG 선박의 선체 운동 중에서 롤 운동에 대한 전달함수를 추정하기 위한 것이다. 단일-입력과 단일-출력 그리고 시스템 전달함수를 갖는 선형 시 불변(Linear Time-Invarient) 시스템을 이용하여 선체 운동 전달함수를 모델링 하였다. 모델의 입력으로 단일 해양파를 이용하고, 모델의 출력으로는 ANSYS를 통해서 획득한 LNG 선박의 롤 운동을 이용하여 시스템 식별법을 기반으로 선체 운동의 전달함수를 추정하였다. 실험 결과의 유용성은 전달함수 차원이 서로 다른 경우에 대한 모델의 안정도와 추정률을 이용하여 평가하였다. 실험 결과 안정도는 99%와 98%로 나타나고, 추정률은 78%와 50%로 나타났다. 이러한 결과로부터, 본 연구에서 제안한 선체 운동 전달함수 추정 방법이 타당함을 알았다. 향후, 실제 해상에서 운항 중인 선박의 선체 운동 데이터를 획득하여 다중-입력 그리고 다중-출력을 갖는 모델 구축에 적용하여 실용화를 추진할 예정이다.

선박이 계류삭을 이용하여 부두에 접안하는 경우, 과도한 선박 속력은 계류삭이 절단되는 사고를 야기할 수 있다. 이러한 계류삭의 파단 사고를 방지하기 위해서는 계류삭 파단 방지에 선박의 한계치 접안 속력을 알아야 한다. 본 연구의 목적은 계류삭 파단을 방지하기 위한 선박의 한계치 접안 속력 추정에 있다. 본 연구의 핵심은 선박의 속력을 모르는 경우 선박제원과 계류삭 제원을 이용하여 접안 시 한계치 접근 속력을 추정하는 방법이다. 본 연구에서는 선체저항과 계류삭의 탄성력 등에 관한 이론을 바탕으로 한계치 접안 속력의 추정 방법과 절차를 제안하였다. 135K LNG 선박과 IWRC, 6×36의 강선 계류삭을 대상으로 한계치 접안 속력을 추정한 결과, 추정한 접안 속력으로 접안하는 경우 계류삭이 파단이 되지 않는 것으로 분석되어 제안한 방법이 유효함을 알았다. 본 연구에서 제안한 방법은 실제 선박에서 계류삭 파단을 방지하는데 기여할 수 있을 것으로 기대된다.

This paper is mainly concerned with the interaction effects between two vessels and sidewall with a mound. Experimental study on hydrodynamic forces between ship and sidewall with a mound was already shown in the previous paper, measured by varying the distances between ship and sidewall. The ship maneuvering simulation was conducted to find out the minimum safe distance between vessels, which is needed to avoid sea accident in confined waters. From the inspection of this investigation, it indicates the following result. When and if one vessel passes the other vessel through the proximity of sidewall with a mound, the spacing between two vessels is needed for the velocity ratio of 1.2, compared to the case of 1.5. Also, for the case of ship-size estimation, the ship maneuvering motion is more affected by interaction effects for the overtaken small vessel, compared to the overtaking large vessel.

새로운 참깨품종 ‘밀성’을 농촌진흥청 작물시험장 영남 시험장에서 2007년에 개발하였다. 교배조합은 이리4호와 ‘수원131호’로 고품질, 다수성, 내병성을 목적으로 하였다. ‘밀성’은 계통육종법을 이용하여 생산력검정시험, 지역적응성 검정시험을 거쳐 개발되었다. ‘밀성’은 소분지이고 3과성, 2실 4방의 꼬투리를 가지고 있다. 그리고 ‘밀성’의 개화기는 7월 1일로 표준품종인 ‘양백’보다 2일 빨랐다. 또한 성숙기는 8월20일로 ‘양백’과 같았다. ‘밀성’의 경장은 129 cm로 ‘양백’과비슷했다. 하지만 ‘밀성’은 ‘양백’보다 많은 27개의 착삭절을가지고 있어 밀삭형이다. ‘밀성’의 천립중은 2.79 g으로 ‘양백’보다 컸다. ‘밀성’의 역병저항성 및 도복저항성은 ‘양백’과비슷했고 ‘밀성’의 수량은 98 kg/10a로 ‘양백’보다 5% 증수하였다. ‘밀성’은 유지함량은 ‘양백’보다 적었으나 단백질함량은 많았다. 지방산 중 올레산의 비율은 45.8%였고 세사민함량은 2.8 mg/g, 세사몰린 함량은 3.0 mg/g이었다.

Maize is expected to be planted in June after harvest of winter barley for the double cropping of forage maize-barley. But maize yield tends to be reduced rapidly with late planting after mid-May, so the pre-requisite of maize variety for the double cropping of maize-barley is less reduction of growth and yield at the condition of late planting in June. In order to select domestic forage maize variety adapted to late planting in June after barley harvest, Kwangpyeong-ok, Gangda-ok and Jangda-ok in 2007 and Kwangpyeong-ok, Gangda-ok and Cheongan-ok in 2008 were planted on June 13 and June 21, and plant growths and yields were compared with early planting on April 24 and May 31, respectively. In 2007, Ear number per plant was as high as 0.98 at Kwangpyeong-ok compared to 0.89 and 0.56 of Gangda-ok and Jangda-ok, respectively, at late planting on June 13. TDN and grain yield of Kwangpyeong-ok were the highest among three variety as 1,037 and 710 kg/10a, and yield reduction of Kwangpyeong-ok compared to early planting were 24% and 28 %, which were 7% and 8% lower than Gangda-ok and 22% and 50% lower than Jangda-ok, respectively. In 2008, TDN and grain yield at late planting on June 21 of Kwangpyeong-ok were also the highest among three varieties as 1,157 and 854 kg/10a at late planting on June 24, and yield reduction of Kwangpyeong-ok by late planting were 21% and 19%, which were 10% and 11% lower than Gangda-ok and 22% and 50% lower than Jangda-ok, respectively. It was concluded that proper maize variety adapted to late planting for the double cropping of forage maize-barley was Kwangpyeong-ok because of its higher ear bearing, less reduction of TDN and grain yields at the condition of late planting.

The object of this study is to develop the method of safe conducting of a vessel through stormy sea when we encounter typoon or hurricane on ocean. The scope of investigation in this paper will be limited to safe maneuvering related only with rolling motions of a vessel. The processes of investigations are as follows; Firstly, we decide a CPA(Closest Point of Approach) with the center of the storm and decide significant wave height(H1/3) by SMB method and then calculate wave height of the highest of 1000 waves(H1/1000) and other data. Secondly, we make mathematical model of rolling motions of the vessel on the stormy sea and calculate the biggest rolling angle of the vessel and etc. Thirdly, we decide the most safe maneuvering method to ride out the stormy sea. By the above mentioned method we are able to calculate the status of the stormy sea and ships motions to be encountered and ride out safely through violently rough sea.

The objective of this paper is to make clear the difference of maneuvering characteristics of a VLCC in standstill from those of her in running. The authors made mathematic models to calculate maneuvering motions of a VLCC in standstill using various ahead engine with full rudder angle and calculated their motions in each case and compared the calculated values with those of the same vessel running in sea trial tests. The difference of motions between them is great. For example, a VLCC in standstill can achieve a great alteration of heading over 90 degrees within the distance of 0.2L advance while she advances 3.0L for 90 degrees turning in full running sea trial turning test. Therefore whenever a VLCC in standstill meets a vessel approaching in collision course situation in near distance, it is better and recommendable that she should use her ahead engine with full rudder to avoid collision. So "maneuvering trial tests in standstill conditions" should be added to the content of sea trial tests when a newly built VLCC commence to take sea trials, that has not been included until now.

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.l37(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning circle test of the actual vessel. (2) Course keeping quality standard : Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard : Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds of actual vessels and examined separately the validity of all criteria of the standard.

The emphasis is put on the detailed knowledge on manoeuvring characteristic for the safe navigation while avoiding terrible collision between ships and on the guideline to the design and operation of the ship-waterway system The numerical simulation of manoeuvring motion was carried out parametrically for different ship types, ship-velocity ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference (hereafter, U2/U1 ) between two ships were considered as 0.6, 1.2, 1.5. From the inspection of this investigation, it indicates the following result. Considering the interaction force only as parameter, the lateral distance between ships is necessarily required for the ship-velocity ratio of 1.2, compared to the cases of 0.6 and 1.5 regardless of the ship types. Furthermore, regardless of the ship-velocity ratio, an overtaking and overtaken vessel can be manoeuvred safely without deviating from the original course under the following conditions: the lateral distance between two vessels is approximately kept at 0.5 times of ship-length and 5 through 10. degrees of range in maximum rudder angle. The manoeuvring characteristic based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in restricted waterways.

This paper is mainly concerned with the assessment of safe navigation between ships moving each other in restricted waterways. The numerical simulation of manoeuvring motion was conducted parametrically to propose an appropriate safe speed and distance, which is required to avoid sea accident under the different conditions, such as ship-velocity ratios, ship-length ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference between two ships were considered as 0.6, 1.2, 1.5 and the ones of ship-length difference were regarded were regarded as 0.5, 1.0, 1.18. From the inspection of this investigation, it indicates the following result. Firstly, the separation between ships is more needed for the small vessel, compared to the large vessel. Secondly, the lateral distance between ships is necessarily required for the velocity ration of 1.2, compared to the cases of 0.6 and 1.5. The manoeuvring characteristics based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in confined water.