• Journal of Fisheries and Marine Sciences Education
• /
• 제26권1호
• /
• pp.126-133
• /
• 2014

For boarding comfort and pleasant boarding sensitivity of passenger in passenger ship, there are a few methods such as motion sickness rate or MSI(Motion Sickness Incidence) to assess safety of passenger ship. To find out MSI or motion sickness rate of the training vessel Kaya of Pukyong National University, we use lots of various factors: sea condition, incident angle in main sail way, economic speed, calculation position of motion sickness, sea state, work place and reduce zone of ship. In this paper, we adopted Maxsurf Seakeeper program based on Strip Theory and carefully compared theoretical results with experimental results.

• Journal of the Korean Society of Marine Environment & Safety
• /
• 제13권4호
• /
• pp.1-7
• /
• 2007

Using field observations, this study estimated the total weight and types of marine debris along the coast of Jinu Island in the Nakdong River Estuary after typhoons Usagi and Nari had passed. A numerical wave model was used to calculate the spatial wave height distribution at the time of the typhoons' passage. This study found that the total accumulation rate of marine debris deposited on the coast after the two typhoons had passed was about $5,769.86\;kg/km^2/day$ at this site, which was 14.42 times as high as that in normal weather. The wave height distribution in the sea off Jinu Island, based on numerical modeling, was $4.1{\sim}3.5\;m$, which was 1.0-2.5 times greater than for the case of other islands. Therefore, it is likely that the concentration of wave energy led to the deposition of marine debris.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권8호
• /
• pp.843-848
• /
• 2015

The objective of this study is to observe and optimize a typical ocean environment and reduce wave reflections in the wave flume. In order to generate ocean waves in the wave flume, a combination of a horizontal piston type wave generator and wave absorbers was installed in the channel. Two probes for measuring the wave heights, i.e., wave level gauges, were used to record the continuous variation of the wave surface, the phase difference, and the maximum (crest) and minimum (trough) points of the propagating waves. In order to optimize the shape and size of the propagating waves, several absorption methods were proposed. Apart from an active wave absorption method, we used methods that involved vertical porous plates, horizontal punching plates, and sloping-wall-type wave absorbers. To obtain the best propagating waves, a sloping-wall-type wave absorber was chosen and tested in terms of the constitutive filling materials and the location and shape of the plate. This study also focused on the theoretical prediction of the wave surface, separating them into the incident and reflective components. From the results, it is evident that the wave absorber comprising a hard filling material exhibits a better performance than the absorber comprising a soft material, i.e., the wave absorber can be a strong sink to control the energy of the incoming wave. In addition, larger wave absorbers correspond to lower reflectance because a larger volume can reduce the incoming wave energy. Therefore, at constant absorber conditions, the reflectance of the wave increases as the wave period increases. Finally, the reflectance of the wave was controlled to be less than 0.1 in this study so that the wave flume can be used to simulate an offshore environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 한국항해항만학회 2012년도 춘계학술대회
• /
• pp.466-468
• /
• 2012

선박산업에서의 국내외 해양사고 통계에 의하면, 모든 해양사고의 80% 정도가 직접적 또는 간접적으로 관련된 인적요인(Human Factors)에 의하여 발생한다고 보고되고 있다. 이러한 해양사고의 원인을 규명함으로써 유사 해양사고의 발생을 방지하고, 또한, 해양사고 조사에 있어서 공통적인 접근방법의 이용과 국가 간의 협력을 증진시키기 위한 목적으로, IMO(International Maritime Organization)에서는 해양사고 인적요인 조사지침(Guidelines for the Investigation of Human Factors in Marine Casualties and Incidents)을 포함한 해양사고조사코드(Casualty Investigation Code: Code of the International Standards and Recommended Practices for a Safety Investigation into a Marine Casualty or Marine Incident)를 채택하였으며, 동 코드는 2010년 1월 1일 발효되었다. 이에 따라, 해양안전심판원에서는, 3단계 절차로 구성된 인적요인 조사 및 분석 방법론을 제안하고, "해양사고 인적요인 분석 매뉴얼"을 마련하였다. 본 논문에서는, 해양안전심판원에서 제안한 인적요인 조사 및 분석 방법론을 실제 해양사고에 적용하여 인적요인 조사분석 모델의 적용사례를 마련하고, 분석 모델을 검토 및 보완하고자 한다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• 제5권2호
• /
• pp.1-14
• /
• 1999

To find characteristics and areas of greater risk of oil spill at the coastal waters in Korea, some of risk factors were analyzed with historical data of oil spill and marine traffic. As a result, it is characterized that frequency of oil spill is increasing year by year and greatest percentage of spill source is fishing boat. It is proposed that the ports of Ulsan, Yeosu, Incheon and Pusan will be designated as primary area of risk as they have a higher risk of oil spills and its response authority is required to maintain appropriate regional response capability for prompt and effective response to a future spill incident. In addition, the regional response equipments at Ulsan are examined under a assumption of a medium size spill and it is found that the use of chemical dispersant can be an alternative when mechanical containment and recovery is not feasible in this area, and the existing response equipments may be appropriate to address that size of spill. However, the response authority is required to maintain more numbers of stronger boom for unsheltered waters and more quantity of concentrate dispersant to disperse all spilled oils on the water, furthermore the response authority should be prepared for a possible future catastrophic spill with sufficient equipments.

• Proceedings of KOSOMES biannual meeting
• /
• 해양환경안전학회 2007년도 추계학술발표회
• /
• pp.15-21
• /
• 2007

Using field observations, this study estimated the total weight and types of marine debris along the coast of Jinu Island in the Nakdong River Estuary after typhoons Usagi and Nari had passed. A numerical wave m며el was used to calculate the spatial wave height distribution at the time of the typhoons' passage. This study found that the total accumulation of marine debris deposited on the coast after the two typhoons had passed was about $5,769.86kg/day/km^2$ at this sitε which was 14.42 times more than during normal weather. The wave height distribution in the sea off Jinu Island, based on numerical modeling， was $4.1^{\sim}3.5$ m, which was 1.0-2.5 times greater than for the case of other islands. Therefore, it is likely that the concentration of wave energy led to the deposition of marine debris.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• 제30권3호
• /
• pp.21-29
• /
• 2016

In this paper, optical tracking and analysis was carried out to find the optical properties with respect to various geometric design parameters of collimator lens which is very efficient when collect the light. As a result, a whole, ellipse incident part can obtain a high light efficiency and a narrow beam angle, and angled cylinder incident part is confirmed to obtain high efficiency and a narrow beam angle at a certain height or more. When Transmission part have a specific surface which can reflect the light in forward direction, a good optical properties was confirmed.

• Fire Science and Engineering
• /
• 제32권6호
• /
• pp.126-133
• /
• 2018

Korea has been preparing and operating crisis management standardized manuals so that over 30 disaster types that need to be managed at the national level can be selected and systematically managed. This study analyzed the crisis alert levels of two standard manuals related to the case with reference to the contents of the Framework Act on the Management of Disaster and Safety and National Crisis Management Basic Guidelines. According to the Act and Guidelines, crisis alerts are issued before a crisis or disaster, but the criteria of crisis alerts of the two manuals showed that the national crisis had already occurred and the disaster occurred due to a marine vessel accident at the serious level. In addition, the results of timing of issuance of crisis alert were reviewed. If the signs can be identified, a crisis alert may be issued prior to the occurrence of the incident, but a crisis alert cannot be issued when an incident occurs without a sign. In the case of an incident where there are no signs, but there is a possibility of spreading to a national level disaster, the disaster management supervision agency could issue a crisis alert.

• Journal of the Korean Society of Marine Environment & Safety
• /
• 제22권1호
• /
• pp.82-89
• /
• 2016

In this study, we proposed a pier of pontoon-type, "Very Large Floating Structure" (VLFS), with the length of 500m, breadth of 200 m and height of 2 m in Yeosu domestic port. Since this structure ought to endure wave loads for long periods at sea, it is essential to analyze the wave response characteristics. Direct-method is used to analyze the fluid-structure problem and the coupled motion of equation is used to obtain response results. The structural part is calculated by using finite element method (FEM) and the fluid part is analyzed by using boundary element method (BEM). Dynamic responses caused by the elastic deformation and rigid motion of structure are analyzed by numerical calculation. To investigate response characteristics of the pier in regular waves, several factors such as the wavelength, water depth, wave direction and flexural rigidity of structure are considered. As a result, wave response of pier changed at the point of $L/{\lambda}$ 1.5 and represented the torsional phenomenon according to the various incident waves. And the responses showed increasing tendency as the water depths increase at the incident point in case of $L/{\lambda}=8.0$ and peak point of vertical displacement amplitude moved from side to side as the flexural rigidity of structure changes.

• Applied Microscopy
• /
• 제38권1호
• /
• pp.51-61
• /
• 2008

This simulation study examined the effect of data acquisition error including the data type of TEM image, and incident beam intensity of the tilt series on 3D tomograms. Simulation was performed with the 3D head phantom model of Kak and Slaney, and the slightly modified 3D head phantom model with enhanced difference in absorption coefficients. Reconstructed tomogram for the original head phantom model using 8-bit gray-scale image was distorted with extremely high level of noise, while an acceptable result was obtained for the modified model. The results for the original model using wrong formulation for the transmitted beam intensity was proved to be incorrect. The high level of noise along the z direction was found in case of the modified model. On the other hand, the wrong value of incident beam intensity in both models gave distorted results. In order to reconstruct an artifacts-free 3D structure from the projections with invisible features in electron tomography, the 16-bit projection images should be used with the correct incident beam intensity which is applied to Beer's law.