Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Marine Environment & Safety
Journal Basic Information
Journal DOI :
The Korean Society of Marine Environment and safety
Editor in Chief :
Volume & Issues
Volume 21, Issue 6 - Dec 2015
Volume 21, Issue 5 - Oct 2015
Volume 21, Issue 4 - Aug 2015
Volume 21, Issue 3 - Jun 2015
Volume 21, Issue 2 - Apr 2015
Volume 21, Issue 1 - Feb 2015
Selecting the target year
Characteristic Distributions of Nutrients and Water Quality Parameters in the Vicinity of Mokpo Harbor after Freshwater Inputs
Kim, Yeong-Tae ; Choi, Yoon-Seok ; Cho, Yoon-Sik ; Choi, Yong Hyeon ; Jeon, Seungryul ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 617~636
DOI : 10.7837/kosomes.2015.21.6.617
The Mokpo coastal waters receive discharges from three artificial lakes(Youngsan, Youngam, Geumho) and other terrigenous freshwater inflows(streams, sewage treatment effluent, fresh groundwater), which exhibit very high concentrations of nutrients and/or organic matters. To understand spatial distributions of nutrients(DIN, DIP, DSi) and other water quality parameters(Chl-a, water temperature, salinity, DO, COD, SS), field surveys were conducted at 10 stations in the Mokpo harbor and adjacent estuaries on May, July, September, and November 2008 within 10 days following discharge events from artificial lakes. In this study, the freshwater flow rate influxed by the operation of sea dike sluice had significant influence on water qualities of the Mokpo coastal waters, although nutrient concentrations in other freshwater sources such as streams, sewage treatment effluent, and fresh groundwater were much higher. As a result of statistical analysis, DIN, COD, and Chl-a had a negative correlation with salinity. Therefore it was shown that discharge extents, time, and nutrients from the Youngsan lake were major impact factors dominating the spatial characteristics of nutrients and other water quality parameters in the Mokpo harbor and adjacent waters. However, despite non-discharge from the Youngsan Lake on September of this investigated period, it was observed that the nutrient addition was taking place in the lower layer of the estuary suggesting nutrient supply through different pathways. This result has emphasized the need to implement the combined assessment about the cumulative impacts on the Youngsan Estuary environment and ecosystem due to freshwater inputs derived from the artificial lakes as well as other terrigenous inflows, or benthic releases.
Improvement of the Estimation Method for Harbor Tranquility of Fishery Harbor
Tac, Dae-Ho ; Kim, Gui-Young ; Jeon, Kyeong-Am ; Lee, Dae-In ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 637~644
DOI : 10.7837/kosomes.2015.21.6.637
In order to estimate harbor tranquility, it is needed to simulate wave propagation in a harbor by using both methods under abnormal wave condition and normal wave condition. The problem is the latter case was not simulated in the statement for the Sea Area Utilization Conference. As harbor calmness about normal wave condition has the same meaning as harbor serviceability, in order to assess harbor tranquility, it is needed to survey wave data for long periods but the survey was not done by reason of a lack of budget and shortage of time for plan. It is more important to make a plan for minimizing environmental impact and to assess an improvement of fisherman's living environmental as the assessment of the harbor serviceability is related with the propriety of the plan. In order to assess it, it is needed to understand it clearly, survey for long period of wave data, and clarify the procedure for computation of it. And also providing wave data like tide and tidal current data from KHOA (Korea Hydro graphic and Oceanographic Agency) and making a guideline for assessing it are needed.
The Conservation Value of Endangered Marine Species: The Case of the Ellobium Chinense
Lim, Seul-Ye ; Lee, Chang-Su ; Kim, Min-Seop ; Yoo, Seung-Hoon ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 645~654
DOI : 10.7837/kosomes.2015.21.6.645
This paper attempts to quantitatively assess the conservation value of Ellobium chinense (EC), which belongs to the endangered marine species designated by Ministry of Oceans and Fisheries. To this end, we apply the contingent valuation (CV) method, an economic technique of valuing a non-market goods such as EC. A national survey of randomly selected 1,000 households was administered in order to derive the public's willingness to pay (WTP) for conserving EC. One-and-one-half-bound model was adopted to elicit the WTP responses and a spike model was employed to deal with the zero WTP responses. The results show that the conservation value of EC is estimated to be 2,346 won per household per year that is statistically significant at the 1% level. Expanding the value to the national population gives us an annual value of 43.8 billion won. We can judge that the Korean people are willing to pay a significant amount to conserve EC.
Marine Ecotoxicological Evaluation on HNS Spill Accident : Nitric Acid Spill Case Study
Kim, Tae-Won ; Kim, Young Ryun ; Jo, So Eun ; Son, Min Ho ; Lee, Moonjin ; Oh, Sangwoo ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 655~661
DOI : 10.7837/kosomes.2015.21.6.655
This study intends to evaluate the effect of nitric acid(
) spill accidents on the marine ecosystem, while
is known as one of the typical HNS. For this purpose, we performed (1) the growth inhibition test by using phytoplankton(Skeletonema costatum), (2) acute and chronic toxicity test by using invertebrate(Brachionus plicatilis and Monocorphium acherusicum), (3) fish(Cyprinodon variegatus) and (4) bacteria(Vibrio fischeri). In these tests, we observed the (1) pH changes induced by the nitric acid spill and (2) changes in nitrate(
) concentration disassociated from nitric acid after the accident, respectively. The toxicity test result on pH changes induced by
shows that the no observed effect concentration(NOEC), lowest observed effect concentration(LOEC) and 50 % effect concentration(
) values of M. acherusicum are pH 7 (0.3 mM), pH 5(1.1 mM) and pH 5.2(1.4 mM), respectively, indicating that M. acherusicum is the most sensitive species. The chronic toxicity test (population growth rate test) on
of B. plicatilis show that the NOEC, LOEC and
are 5.9 mM, 11.8 mM and 32.6 mM, respectively, indicating that B. plicatilis is the most sensitive species. In conclusion, toxic effecst on the marine organism caused by the nitric acid spill accident is determined to be so slightly except for the most adjacent area of the ship in pH scale and such concentration of nitrate, to the extent of directly influencing the survival and reproduction of the marine organism, is determined practically not to be applicable in the typical accidents in the sea.
Comparison of Response Systems and Education Courses against HNS Spill Incidents between Land and Sea in Korea
Kim, Kwang-Soo ; Gang, Jin Hee ; Lee, Moonjin ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 662~671
DOI : 10.7837/kosomes.2015.21.6.662
As the type of Hazardous and Noxious Substances(HNS) becomes various and the transport volume of HNS increases, HNS spill incidents occur frequently on land and the sea. In view of various damages to human lives and properties by HNS spills, it is necessary to educate and train professional personnel in preparation for and response to potential HNS spills. This study shows the current state of response systems and education courses against HNS spill incidents on land and the sea to compare those with each other between land and sea in Korea. Incident command system on land are basically similar to that at sea, but leading authority which is responsible for combating HNS spills at sea is changeable depending on the location of HNS spill, as it were, Korea Coast Guard(KCG) is responsible for urgent response to HNS spill at sea, while municipalities are responsible for the response to HNS drifted ashore. Education courses for HNS responders on land are established at National Fire Service Academy(NFSA), National Institute of Chemical Safety(NICS), etc., and are diverse. Education and training courses for HNS responder at sea are established at Korea Coast Guard Academy(KCGA) and Marine Environment Research & Training Institute(MERTI), and are comparatively simple. Education courses for dangerous cargo handlers who work in port where land is linked to the sea are established at Korea Maritime Dangerous Goods Inspection & Research Institute(KOMDI), Korea Port Training Institute(KPTI) and Korea Institute of Maritime and Fisheries Technology(KIMFT). Through the comparison of education courses for HNS responders between land and sea, some recommendations such as extension of education targets, division of an existing integrated HNS course into two courses composed of operational level and manager level with respective refresh course, on-line cyber course and joint inter-educational institute course in cooperation with other relevant institutes are proposed for the improvement in education courses of KCG and KOEM(Korea Marine Environment Management Corporation) to educate and train professionals for combating HNS spills at sea in Korea.
A Study on Prioritization of HNS Management in Korean Waters
Kim, Young Ryun ; Kim, Tae Won ; Son, Min Ho ; Oh, Sangwoo ; Lee, Moonjin ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 672~678
DOI : 10.7837/kosomes.2015.21.6.672
The types of hazardous and noxious substances (HNS) being transported by sea in Korea are at about 6,000, HNS transport volume accounts for 19% of total tonnage shipped in Korea, and the increase rate of seaborne HNS trade in Korea is 2.5 times higher than the average increase rate of the world seaborne HNS trade. Reflecting this trend, HNS spill incidents have been frequently reported in Korean waters, and there are increasing social demands to develop HNS management technology for the preparedness, response, post-treatment and restoration in relation to HNS spill incidents at sea. In this study, a risk-based HNS prioritization system was developed and an HNS risk database was built with evaluation indices such as sea transport volume, physicochemical properties, toxicities, persistency, and bioaccumulation. Risk scores for human health and marine environments were calculated by multiplying scores for toxicity and exposure. The top-20 substances in the list of HNS were tabulated, and Aniline was ranked first place, but it needs to be managed not by individuals but by HNS groups with similar score levels. Limitations were identified in obtaining data of chronic toxicity and marine ecotoxicity due to lack of testing data. It is necessary to study on marine ecotoxicological test in the near future. Moreover, the priority list of HNS is expected to be utilized in the development of HNS management technology and the relevant technologies, after the expert's review process and making up for the lack of test data in the current research results.
Study on the Energy Security Strategy of South Korea - Focused on the Innovation System Perspective -
Choi, Jeong-Hwan ; Lee, Hong-Hoon ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 679~688
DOI : 10.7837/kosomes.2015.21.6.679
Stability and security of energy resources are one of the most important factors for a national-development. In this research, we analyzed the Republic of Korea's policy making system on energy security and identified the problems from an innovation system perspective. In terms of the actors, they had limitations that ROK's navy do not have enough strategic plan for energy transportation. The links between innovation actors except defense area were relatively good, but links between the military area(navy) and other innovation actors had weak linkage. The infrastructure did't have enough consideration for military force development. For the institution; the role of the military area on energy security was not completely established. Therefore, participation of the defense area(navy) is required to be stated institutionally.
A Study on Improving the Efficiency of the Survival Rate for the Offshore Accommodation Barge Resident Using Fire Dynamic Simulation
Kim, Won-Ouk ; Lee, Chang-Hee ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 689~695
DOI : 10.7837/kosomes.2015.21.6.689
The offshore plant crews that were commissioned in the commercial startup phase boarded the offshore plant in two shifts until the end of the project. The crews who were hired by the owner side stayed in the original offshore plant during the project. However, most of the offshore plant commissioned members who were dispatched from the shipyard were accommodated in the offshore accommodation barge. For this reason, they were exposed to many accidents since there are a lot of people staying in a small space. This study suggested a method for improving survival rate at offshore accommodation barge in terms of life safety. It is assumed that the fire accident among unfortunate events which take place in the offshore accommodation barge mainly occurred. So, this study analyzed the safety evacuation for offshore plant employees using fire simulation model based on both domestic and international law criteria. In particular, When fire occurs in the offshore accommodation barge, the periodically well trained crews are followed safety evacuation procedure. whereas many employees who have different background such as various occupations, cultural differences, races and nationality can be commissioned with improper evacuation behaviors. As a result, the risk will be greater than normal situation due to these inappropriate behaviors. Therefore, This study analyzed the Required Safe Escape Time (RSET) and Available Safe Escape Time (ASET). Also it was suggested the improvement of structure design and additional arrangement of safety equipment to improve the survival rate of the residents in offshore accommodation barge.
A Study on the Development of Evaluation Index for Safety Management Level of Shipping Company(2) : Development of Evaluation Items for Safety Management Index
Kim, Joo Hwan ; Kim, Hwa Young ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 696~703
DOI : 10.7837/kosomes.2015.21.6.696
This paper is a follow-up research of 'A study on the development of Safety Management Evaluation Index for Shipping Company'. It aims to develop the evaluation items of Safety Management Index(hereafter called as 'SMI') applicable to 'Safety Advantage Point', which is suggested as the sub-index of 'Safety Management Evaluation Index' function in the preceding research and also verify their adequacy. For that purpose, firstly, the 11 evaluation items were developed after collecting the practical opinions from safety management personnels in Korean shipping companies. Secondly, the survey was carried out for the verification of the adequacy of the 11 evaluation items. And lastly, its results was analysed, whether it has statistical meanings of differences in adequacy awareness amongst safety managers grouped depending on business type(coastal, ocean-going) and business capacity(number of owned-operating ships). As a result, there was no relevance between their adequacy awareness and business type of their companies. However, a difference in their adequacy awareness existed depending on their companies' business capacity(small, medium and large sized). In conclusion, when the safety management level of shipping companies is evaluated by SMI, the same indices can be applicable to both coastal and ocean-going shipping companies by a grouping of companies' business capacity.
A Study on the Improvement of Risk Assessment Items and Index for Sunken Ship
Lee, Seung-Hyun ; Choi, Hyuek-Jin ; Suh, Jae-Joon ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 704~711
DOI : 10.7837/kosomes.2015.21.6.704
In this study, we have conducted a survey of AHP technique through the ocean experts to derive new items and revise assessment items and indices for risk of sunken ships based on the survey results. As a result of the survey, two new items such as accident cause and tidal current are derived. And it shows that existing items such as toxic liquid substance, remaining oil and explosive gas which were evaluated as one group are desirable to be evaluated respectively. Accordingly, we analyze the indices of the new eleven assessment items adjusted from the existing seven assessment items. As a result, the indices are ordered by toxic liquid substance, possibility of leaking, explosive gas, carrying capacity of fuel oil, sensitivity of sea environment, marine traffic environment, cause of accident, tidal current, keel clearance, ship type, and ship size. Especially, as compared with the indices of existing assessment items, the indices of sensitivity of sea environment and possibility of leaking are higher and the index of keel clearance is lower.
A Study on the Seafarers Education for Cabotage in KOREA
Kim, Sung-Kuk ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 712~720
DOI : 10.7837/kosomes.2015.21.6.712
The cabotage rule has been protecting the domestic industry from foreign competitions as a kind of trade barrier. In the United States, the shipbuilding industry has been maintained with the help of to the strict cabotage operations by reinforcing advantages for domestic crews and ships which are built in the U.S. For most countries, cabotage has been granted legitimacy in their coastal shipping by Low Carbon Transport in terms of economic and emergency reasons. The cabotage rule is required in the stable supply of the seafarers which rely on the legitimate maritime education. This study analyzes Korean cabotage system and the problems with regard to seafarers education. It is found that the resolution is set up the cabotage act such as Jones Act, U.S.
Impact of Emotional Labor on Job Burnout Marine Police Officials
Kim, Jong-Gil ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 721~728
DOI : 10.7837/kosomes.2015.21.6.721
Due to paradigm shift in administration, the field of police administration, like its civilian counterpart, is spending effort to improve customer-oriented civil complaint service system, and this is leading to a negative factor in service providers, emotional labor, among police officers. This study examines amount of emotional labor of maritime police officers, and verify the effects of emotional labor on exhaustion. Results show maritime police officers experience about the same amount of emotional labor as other public workers, and emotional labor has effects on work exhaustion. In other words, perception of incongruity of emotion has positive effects on exhaustion on cynical attitude. Attention to emotional expression has negative effects on decrease of job effectiveness. As such, if the problem of emotional labor is neglected, it leads to exhaustion and can become a significant obstacle to performance due to negative organizational influence. Also, it can lead to serious physical and mental problems on the individual level. Therefore, policy implementation to prevent this problem is necessary.
Basic Research on Structural Optimum Design of G/T 250ton Class Double-ended Car-Ferry Ship
Kang, Byoung-Mo ; Oh, Young-Cheol ; Seo, Kwang-Cheol ; Bae, Dong-Gyun ; Ko, Jae-Yong ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 729~736
DOI : 10.7837/kosomes.2015.21.6.729
In this paper, It was performed to optimize for the deck's structural design of a double ended car ferry ship respect to Goal-Driven Optimization (GDO). It was examined for the strength and deformation of the deck and determined to save economic cost the optimal point. The deck thickness based on the Design of Experiments (DOE) and response surface method was increased to 110%. and can improve the deck's strength and stiffness. By performing the regression analysis respect to the result, we propose the optimal regression model formula as a third degree polynomial regression models. The coefficient of determination
was about 0.98 and reliability could be obtained.
Analysis of Radar Cross Section for Naval Vessels with Metamaterials and Radar Absorbing Materials
Hwang, Joon-Tae ; Hong, Suk-Yoon ; Kwon, Hyun-Wung ; Kim, Jong-Chul ; Song, Jee-Hun ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 737~743
DOI : 10.7837/kosomes.2015.21.6.737
This paper are mainly focusing on the facts influencing on RCS reductions, appling radar absorbing materials by using RCS contributions of elements and appling a metamaterials which is high-tech radar absorbing materials. RCS analysis results are given for a simplified ship model, with radar absorbing materials and metamaterials cause RCS reduction in terms of mean values.
A Study on the Development of Mobile Robot for Inspection of Hull Surface
Kim, Jin-Man ; Kim, Heon-Hui ; Nam, Taek-Kun ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 744~750
DOI : 10.7837/kosomes.2015.21.6.744
In this paper, development of mobile robot for the inspection of hull surface was mentioned. In the sea, it is difficult to proceed with the visual inspection of hull side and thus mobile robot for checking the status could be run with strap-on its surface. To do this, permanent magnet module to generate magnetic force between hull surface and mobile robot, and structure to minimize variance of the force under curvature circumstance were considered on the design. Based on the design, mobile robot with four NdFeB, four driving wheels and image aquisition module was applied. Load experiment to check the adhesive force, slip test during stop state and driving test to measure driving speed were executed. From the experiments 13 Kgf adhesive force was obtained and slip was not happened until 8 Kgf load on the inclined plate. Driving speed of mobile robot was measured at 0.82 m/s corresponding to 6.5 ampere. We confirmed the effectiveness of developed mobile robot by experiments to check its characteristics.
Computational Analysis on the Noise Characteristics of Ship Large Duct
Song, Jee-Hun ; Hong, Suk-Yoon ; Lee, Yi-Soo ; Kwon, Hyun-Wung ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 751~758
DOI : 10.7837/kosomes.2015.21.6.751
Noise prediction for HVAC(Heating, Ventilating and Air Conditioning) systems are normally performed by empirical method suggested by NEBB(National Environmental Balancing Bureau, 1994). However, the method is not suitable for large ducts in ships. In this paper, computational analysis methods are used to develop a noise prediction method for the large ducts in ships. To develop regression formula of attenuation of sound pressure level in large ducts, Boundary Element Method(BEM) is used. BEM and Computational Fluid Dynamics(CFD) are applied to the analysis of flow-induced noise in ducts with stiffeners inside. Loud noise above 100 dB can be generated in some cases. Breakout noises of large ducts are also analyzed by using BEM and Finite Element Method(FEM). The acoustic pressure level shows about 10-15dB difference between inside and outside of the duct. Utilizing the results of this study, it is expected that shipyard planners can predict noise of the HVAC system for ships.
Harmonic Reduction Scheme By the Advanced Auxiliary Voltage Supply
Yoon, Doo-O ; Yoon, Kyoung-Kuk ; Kim, Sung-Hwan ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 759~769
DOI : 10.7837/kosomes.2015.21.6.759
Diode rectifiers are very popular in industry. However, they include large low-order harmonics in the input current and do not satisfy harmonic current content restrictions. To reduce the harmonics to the power system, several methods have been introduced. It is heavy and expensive solution to use passive filters as the solution for high power application. Another solution for the harmonic filter is utilization of active filter, but it is too expensive solution. Diode rectifiers with configurations using switching device have been introduced, but they are very complicated. The combined 12-pulse diode rectifier with the square auxiliary voltage supply has been introduced. It has the advantages that auxiliary circuit is simple and inexpensive compared to other strategies. The advanced auxiliary voltage supply in this thesis is presented as a new solution. When the square auxiliary voltage supply applied, the improvement of THD is 6~60[%] in whole load range. But when the advanced auxiliary voltage supply applied, it shows stable and excellent reduction effect of THD as 57~71[%]. Especially, for the case with 10[%] load factor, reduction effect of THD has little effect as 6[%] in the case of inserting a square auxiliary voltage supply. But when the proposed new solution applied, reduction effect has excellent effect as 71[%]. Theoretical analysis of the combined 12-pulse diode rectifier with the advanced auxiliary voltage supply is presented and control methods of the auxiliary supply is proposed. The reduction in the input current harmonics is verified by simulation using software PSIM.
An Analysis on the Effectiveness of Harmonics Reduction for Variable Frequency Drive by Reactors
Kim, Deok-Ki ; Yoon, Kyoung-Kuk ; Kim, Hee-Moon ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 770~777
DOI : 10.7837/kosomes.2015.21.6.770
Recently, due to the rapid development of Power Electronics, the usage of Non Linear Load variable frequency drivers (VFDs) is increasing in the electric propulsion vessels and offshore plants. And harmonics which is generated by the variable frequency drives is an important issue should be solved. Ac line reactors and dc link reactors are widely used in variable frequency drives to improve the drive performance such as reducing input current harmonics, elevating input power factor, and protecting the drives from surges, etc. The effectiveness of both types of reactors in reducing input harmonics is affected by the loading of the drives and the system source impedance. And it considered that inductance of DC link reactors should be about 1.7 times of AC line reactors for same effect. The rules to evaluate the needs and effectiveness using ac line or dc link reactors are proposed for practical appications. In this paper, a simulation is performed to investigate of such factors using software PSIM.
A Study on the Strength Characteristics of the FRP Bonding Method
Kim, Kung-Woo ; Kang, Dae-Kon ; Baek, Myoung-Kee ; Park, Jai-Hak ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 778~783
DOI : 10.7837/kosomes.2015.21.6.778
We studied about the strength characteristics of the FRP bonding method due to reduce accident on the oceans and protect life for my people. We test tension and bending strength of butt joint, lap joint, V-scarf joint, X-scarf joint. The result of test, it's pattern is similar both tension and bending strength. Tension strength and bending strength was excellent in order to X-scarf-butt joint-V-scarf-lap joint. The tension strength is the best properties X-scarf showed a 57% strength rate of the basic material, and bending strength showed a 77% strength rate of the basic material. Overall, the X-scarf 12t joint has most excellent properties of tension and bending strength. The lap joint has worst properties of tension and bending strength. We have to test having different over-lay of V-scarf and X-scarf joint each 12t, 16t, 20t. V-scarf of 20t over-lay has excellent character of tension and bending strength. But X-scarf of 12t over-lay has excellent character of tension and bending strength. The results are shown to the contrary. The ship is received a lot of stress. it's hard to compare a direction both actual and test. But we can acknowledge material basic characteristic of strength through tension and bending test. We give the four repair method; butt joint, lap joint, V-scarf joint, X-scarf joint and the reduced ratio in comparison with basic material; In addition give the separated data for V-scarf and X-scarf characteristic of 12t, 16t, 20t overlay length. For our study repair man can select good repair method in his work station.
A Study on Operating Limit Analysis for Small High-speed Boat
BAE, Jun-Young ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 784~789
DOI : 10.7837/kosomes.2015.21.6.784
It was carried out a review of operating limit analysis for small high-speed boat by author. In general, a review of ship's seakeeping performance is performed in the step of ship design, but this study was carried out in the state of completion of boat. Motion performance of Pitch, Vertical and Lateral acceleration and Slamming were satisfied in some encounter angle but deck wetness was not satisfied in all it does the analysis. As a result, sea state rather than the speed and encounter angle of vessel have a greater effect on the seakeeping performance of target vessel. It seems to be due to the size of the target ship.
A Case Study of Nitrox Usage in Diving Operation of the Busan-Geoje Fixed Link Immersed Tunnel
Woo, Dae-Hee ; Kang, Sin-Young ; Lee, Min-Gu ;
Journal of the Korean Society of Marine Environment & Safety, volume 21, issue 6, 2015, Pages 790~797
DOI : 10.7837/kosomes.2015.21.6.790
This study tried to evaluate the safety and economical benefit of Nitrox-diving by comparing with Air diving. We used actual diving data which was recorded in construction site of the Busan-Geoje fixed link immersed tunnel in 2010. The study method was to assort and analyze the diving data by divers, depth, breathing air, and diving table. Furthermore, the study examined the possibility of outbreak decompression sickness by comparing Nitrox diving and Air diving in no-decompression limit time, decompression time, working time. As a result, this study confirms that if certain diver breathe Nitrox for diving and oxygen for decompression, not only the risk of decompression sickness could be minimized, but also duration of decompression could be shortened. Moreover, it was estimated that a remarkable difference(more than 3 times) between actual duration of underwater construction period and virtual construction period by using air. As a result, the study confirmed that Nitrox diving is more efficient and economical than Air diving in physically limited and hazardous diving environment.