• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.343-350
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• 2004

LNGC suffers a great heat inflow during navigation and this heat inflow inevitably boils off the LNG. The boiled off gas(BOG) is normally consumed as a fuel for ship's engine. The boiled off LNG means a loss of cargo during transportation from the viewpoint of shipper. Therefore, a contract between shipper and ship operator is made on the limit of boiled off rate(BOR) under 0.15 ％／day based on laden voyage. This contract on BOR limit requires that ship's officer has a correct knowledge on BOR for his ship. But, in most cases ship is operated based on only officer's experiences. In this study, author presented a simple model to predict the boiled off gas(BOG) during navigation based on the existing precision heat exchange design technology about the heat distribution on the hull and heat inflow from outside through the hull. The BOG is calculated for ballast and laden voyage based on the actual weather conditions and verified by comparing with the measured BOG for the study ship. The study ship is a membrane type LNGC which is now servicing in Middle east route. Thus, the BOG prediction method which is presented in this study is expected to be used for an useful tool to manage the BOG in now servicing LNGC.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.365-372
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• 2004

LNGC suffers a great heat inflow during navigation and this heat inflow inevitably boils off the LNG. The boiled off gas(BOG) is normally consumed as a fuel for ship's engine. The boiled off LNG means a loss of cargo during transportation in the viewpoint of shipper. Therefore, a contract between shipper and ship operator is made for the limitation of BOR under 0.15 ％/day based on laden voyage. This contract on BOR limit requires that ship's officer has a correct knowledge on BOR for his ship. nut, in most cases ship IS operated based on only officer's experiences. In this study, author presented a simple model to predict the BOG during navigation based on the existing precision heat exchange design technology about the heat distribution on the hull and heat inflow from outside through the hull. The BOG is calculated for ballast and laden voyage based on the actual weather conditions and verified by comparing with the measured BOG for the study ship. The study ship is a membrane type LNGC which is now servicing in Middle east route. Thus, the BOG prediction method which is presented in this study is expected to be used for an useful tool to manage the BOG in now servicing LNGC.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.827-837
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• 2022

If the hydrogen industry is activated, the introduction of C-type and pressurized liquefied hydrogen (LH2) tank suitable for small and medium-sized transp- ortation and storage will be given priority in the future. Therefore in this paper, the behavior for the LH2 property changes and boil-off gas (BOG) treatment of the C-type cargo tank through voyage of the LH2 carrier and pressurized tank of the LH2 receiving terminal were analyzed through computational simulations by making assumptions about the carrier operation and unloading conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.191-193
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• 2015

우리나라 산업단지의 수출경쟁력은 중국 등 주변 국가들의 원가에 상대적으로 취약하다. 수출경쟁력 차원에서 원가를 구성하는 항목들은 여러가지가 있겠으나, 원가절감이 가능한 항목은 그리 많지 않다. 본 연구에서는 국내 수출기업들의 수출경쟁력 향상을 위해 해상물류비용의 절감이 가능한 방안을 탐색하여 연구하였다. 특히 해외에서 소금과 같은 살화물을 수입하고 공선으로 나가 다시 수입하는 벌크선의 경우에는 국내에서 공선상태로 나가는 선박을 대상으로 컨테이너 적재가 가능한 겸용선으로 개조하여 운항시에 컨테이너로 수출하는 해상물류비용을 낮출 수 있다. 따라서 산업단지의 수출기업들이 이를 활용하면 해상물류비용을 획기적으로 낮출수 있으므로 수출경쟁력을 향상시킬수 있고, 이러한 절감방안 모델은 정부, 항만운영사업자, 수출기업 및 하역사업자 모두에게 도움이 되는 모델로 해상물류비용을 절감하기 위해 충분한 연구 가치가 있다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.81-82
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• 2018

선박안전법에 따라 대다수의 관공선 주기관은 8년마다 정기 개방검사를 해야 한다. 주기관 특성상 개방검사는 많은 예산 소요 및 엔진 효율성의 저하가 우려되어 이를 해결하고자 관련법에 따라 8년간 개방검사 면제 사전 준비로 예산을 절감하고 기관의 성능을 최적화 시켰다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.99-101
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• 2011

접이안 조선은 도선사들의 필수 업무에 해당하는 것이며 이에 대한 안전성 확보는 무엇보다 중요하다. 새로운 항만의 개발, 새로운 선형 선박의 등장 등으로 도선사가 접이안 하는 항만은 계속 그리고 빠르게 변화하고 있다. 이런 변화에 능동적으로 대처하여 도선사 개개인의 선박조종 능력을 함양할 수 있는 방법의 하나로서 도선사들이 쉽게 어디서나 접할 수 있도록 랩탑(laptop) 기반의 선박조종 시뮬레이터를 개발하였다. 도선사들이 다루는 선박에서는 통상의 정속의 항행속력이 아닌 저속에서의 선박 조종이 주가 되므로 이에 대하여 특별히 고려하여 선박모델을 개발하였다. 선박 텔러그래프의 해당 속력 및 그 속력에 도달하는 시간 등이 실선에 부합할 수 있도록 하였다. 선박은 일본의 MMG 모델을 기반으로 하였으며 실제 선박의 시운전 데이터를 참고하여 개발하였다. 실선박이 가진 시운전 자료는 공선의 경우가 많으므로 이에 대하여서는 각 도선사들의 자문을 받아 수정 보완하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.129-131
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• 2011

해상기상은 재박 및 운항 선박의 안전에 중요한 영향을 미친다. 따라서, 관제구역에서 선박 안전운항을 관리하는 VTS에 있어 기상예보 및 국지적 실시간 기상정보를 모니터링 하여 대상선박에 대해 사전 안전조치를 취하거나 실무 관제에 중요한 참고자료로 활용해야 함이 해양사고 예방을 위해서 절대적으로 요청되고 있다. 이 논문에서는 겨울철 기압골 형성에 따라 동해안에서 자주 발생하고 있는 북동방향으로 부터의 스웰 유입에 대해, 2011년 1월 1일 포항항에 큰 스웰 유입 당시의 해상기상에 대한 예보 및 실측 자료를 분석하여, 문제점을 고찰하고 선박관제 운용에 있어 기상정보 활용의 중요성을 부각시키고자 노력 하였다. 아울러, 기상청 홈페이지에서 제공하고 있는 상세 기상정보를 선박관제 운용에 활용하고 있는 포항청 사례를 소개하여 타 항만에서도 해상기상 악화에 대비 대응할 수 있는 방안 모색에 도움이 되고자 한다.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.335-343
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• 2019

As the regulations of ship exhaust gas have been strengthened recently, many measures are under consideration to reduce fuel consumption. Among them, research has been performed actively to develop a machine-learning model that predicts fuel consumption by using data collected from ships. However, many studies have not considered the methodology of the main parameter selection for the model or the processing of the collected data sufficiently, and the reckless use of data may cause problems such as multicollinearity between variables. In this study, we propose a method to predict the fuel consumption of the ship by using the principal component analysis to solve these problems. The principal component analysis was performed on the operational data of the 13K TEU container ship and the fuel consumption prediction model was implemented by regression analysis with extracted components. As the R-squared value of the model for the test data was 82.99%, this model would be expected to support the decision-making of operators in the voyage planning and contribute to the monitoring of energy-efficient operation of ships during voyages.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.111-121
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• 1999

From the traffic analyses, and model constructions and verifications for speed prediction on the freeway ramp junctions with 70mph speed limit, the following results obtained: ⅰ) The traffic flow distribution showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period when compared with the afternoon peak period. ⅱ) The occupancy distribution was also shown to be varied by a big difference depending on the time periods. Especially, the occupancy in the morning peak period showed over 100% increase when compared with the 24hours average occupancy, and the occupancy in the afternoon peak period over 25% increase when compared with the same occupancy.ⅲ) The speed distribution was not shown to have a big difference depending on the time periods. Especially, the speed in the morning peak period shown 10mph decrease when compared with the 24hours' average speed, but the speed did not show a big difference in the afternoon peak period.ⅳ) The analyses of variance showed a high explanatory power between the speed predictive models(SPM) constructed and the variables used, especially the upstream speed. ⅴ) The analysis of correlation for verifying the speed predictive models(SPM) constructed on the ramp junctions were shown to have a high correlation between observed data and predicted data. Especially, the correlation coefficients showed over 0.95 excluding the unstable condition on the diverge sectionⅵ) Speed predictive models constructed were shown to have the better results than the HCM models, even if the speed limits on the freeway were different between the HCM models and speed predictive models constructed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.131-140
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• 1999

Today freeway is experiencing a severe congestion with incoming or outgoing traffic through freeway ramps during the peak periods. Thus, the objectives of this study is to identify the traffic characteristics, analyze the relationships between the traffic characteristics and finally construct the delay predictive models on the ramp junctions of freeway with 70mph speed limit. From the traffic analyses, and model constructions and verifications for delay prediction on the ramp junctions of freeway, the following results were obtained: ⅰ) Traffic flow showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period when compared with the afternoon peak period. ⅱ) The occupancy also showed a big difference depending on the time periods, and the downstream occupancy(Od) was especially shown to have a higher explanatory power for the delay predictive model construction on the ramp junction of freeway. ⅲ) The speed-occupancy curve showed a remarkable shift based on the occupancies observed ; Od < 9% and Od$\geq$9%. Especially, volume and occupancy were shown to be highly explanatory for delay prediction on the ramp junctions of freeway under Od$\geq$9%, but lowly for delay predicion on the ramp junctions of freeway under Od<9%. Rather, the driver characteristics or transportation conditions around the freeway were through to be a little higher explanatory for the delay perdiction under Od<9%. ⅳ) Integrated delay predictive models showed a higher explanatory power in the morning peak period, but a lower explanatory power in the non-peak periods.