• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2003년도 춘계공동학술대회논문집
• /
• pp.242-248
• /
• 2003

본 논문에서는 다양한 종류와 다양한 크기의 화물에 대해 3차원 적재하는 방법으로서 휴리스틱 기법을 이용한 해법을 제안하였다. 먼저, 컨테이너 비용을 적재비용, 수송비용 및 처리비용의 합으로 나타내며. 화물간 우선순위 및 화물 내에서의 개수 간 우선순위를 적용하였다. 주어진 화물을 적재 공간 및 중량을 만족하면서 위의 컨테이너 비용을 최소화하는 컨테이너 종류 및 개수를 산출하였으며, 적재 시 화물의 팔레타이져 및 디팔레타이져로서 컨테이너 내의 공간 이용률을 극대화시켰다. 마지막으로 화물의 무게 균등화를 고려하여 취급중의 화물의 손상방지를 행하였다.

• 전기학회논문지P
• /
• 제64권2호
• /
• pp.74-78
• /
• 2015

With the improvement of living standards and economic development, electricity consumption continues to grow. The electricity is a special energy which is hard to store, so its supply must be consistent with the demand. The objective of electricity demand forecasting is to make best use of electricity energy and provide balance between supply and demand. Hence, it is very important work to forecast electricity demand with higher precision. So, various forecasting methods have been developed. They can be divided into five broad categories such as time series models, regression based model, artificial intelligence techniques and fuzzy logic method without considering special-day effects. Electricity demand patterns on holidays can be often idiosyncratic and cause significant forecasting errors. Such effects are known as special-day effects and are recognized as an important issue in determining electricity demand data. In this research, we developed the power demand forecasting method using ELM(Extreme Learning Machine) for special day, particularly, lunar new year and Chuseok holiday.

• Environmental Engineering Research
• /
• 제24권2호
• /
• pp.220-237
• /
• 2019

Solid waste management (SWM) is one of the poorly rendered services in developing countries - limited resources, increasing population, rapid urbanization and application of outdated systems leads to inefficiency. Lack of proper planning and inadequate data regarding solid waste generation and collection compound the SWM problem. Decision makers need to formulate solutions that consider multiple goals and strategies. Given the large number of available options for SWM and the inter-relationships among these options, identifying SWM strategies that satisfy economic or environmental objectives is a complex task. The paper develops a mathematical model for a municipal Integrated SWM system, taking into account waste generation rates, composition, transportation modes, processing techniques, revenues from waste processing, simulating waste management as closely as possible. The constraints include those linking waste flows and mass balance, processing plants capacity, landfill capacity, transport vehicle capacity and number of trips. The linear programming model integrating different functional elements was solved by LINGO optimization software and various possible waste management options were considered during analysis. The model thus serves as decision support tool to evaluate various waste management alternatives and obtain the least-cost combination of technologies for handling, treatment and disposal of solid waste.

• 한국기계가공학회지
• /
• 제18권5호
• /
• pp.23-28
• /
• 2019

In recent years, medium- to large-scale transportation machinery and machine tool manufacturing process lines have shown a trend toward centralization, softening, lightening, and slimming to reduce costs and increase productivity. This has increased the demand for vertical articulated robots. When developing and introducing a heavy weight-handling robot that can be easily applied to existing production lines, it is expected to have a great effect in securing industrial competitiveness by solving industrial issues such as the decreased productivity and increased risk of accidents due to work involving heavy lifting. In this study, we design a 6-axis robot mechanism with a heavy load-handling capacity of 700kg or more for large-sized materials of various types supplied in small quantities.

• 국토계획
• /
• 제54권4호
• /
• pp.26-37
• /
• 2019

It is necessary to implement a wide range of housing welfare policies that citizens can experience in order to improve residents' the quality of life, as it emphasizes the balance of supply and management of public housing. The purpose of this study is to analyze the factors affecting residential satisfaction considering the three hierarchical levels of individual, household, and area. In the background of the study, the individuals' quality-of-life satisfaction determined not only by the individual but also by the various influencing environmental factors. This study targets 1,736 households, 3,239 persons in 464 areas in Seoul. The main research results are as follows. At the level one, there were influencing factors such as age(-), education level and income, and housing area per person, recipient of basic living(-), period(-) and RIR (at the level two). At the level three, west-south region(-) and social mix affect the complex of public housing. In consideration of living infrastructure, the closer to public transportation, public facilities, and medical facilities, the higher the satisfaction of public housing. The results of this analysis suggest that public support needs to focus on individual household members, but there is a need for ways to link it with the complex and the region.

• Strategy21
• /
• 통권30호
• /
• pp.200-235
• /
• 2012

Over the past few years, due to the climate change of the earth, the Arctic's sea ice cover is undergoing a historic transformation - thinning, extent reduction in all seasons, and mitigation in the area of multi-year ice in the central Arctic Ocean. These changes allow for increases in maritime access throughout the Arctic Ocean and for potential longer seasons of navigation and possibly transarctic voyage in the summer. These changes also allow more exploration for oil, gas, and other minerals. The Arctic is now an archetype of the complex, multi-dimensional global problems of the twenty-first century. Military security, environmental security, and economic security interact. The potentially enormous economic stakes, sufficient to change the strategic balance among the states of the region, set off competitive pressures for national advantage. Korea, which is heavily dependent upon the sea lane in terms of transportation of its exports and imports, is very much interested in the Arctic sea routes. Korea believes that the Artic sea route, particularly the Northern Sea Route (NSR), could serve as a new useful sea lane, which will enable shorter times between East Asia and Europe, thus resulting in substantial cost saving for ship operators. In addition to shipping, Korea is interested in other Arctic-related maritime industries. Korea, as a leading shipbuilder in the global market, is interested in building ice breakers, drill ships, and other vessels which can contribute to safe operation in Arctic resource development and exploration. Korea, as one of the future stakeholders in Arctic maritime activities, should be ready to foster international cooperation in the region.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2023년도 추계학술대회
• /
• pp.120-121
• /
• 2023

최근에 해운산업의 수요와 공급이 지속적으로 일치하지 않으면서 불균형 현상이 이어지고 있다. 이에 따라 해운선사들은 선박의 공급량을 조절하기 위해 블랭크 세일링을 실시하며 수요와 공급의 균형을 맞추고 있다. 블랭크 세일링은 화물 운송을 지연시키는 부정적인 연쇄효과를 발생시키기 때문에 본 연구에서는 포아송 회귀분석을 이용하여

• Tribology and Lubricants
• /
• 제40권3호
• /
• pp.71-77
• /
• 2024

Hydrogen has emerged as an eco-friendly and sustainable alternative to fossil fuels. However, the utilization of hydrogen requires high-pressure compression, storage, and transportation, which poses challenges to the durability of compressor components, particularly the diaphragm. This study aims to improve the durability of 304 stainless steel diaphragms in hydrogen compressors by optimizing their surface roughness and corrosion resistance through wet etching. The specimens were prepared by immersing 304 stainless steel in a mixture of sulfuric acid and hydrogen peroxide, followed by etching in hydrochloric acid for various durations. The surface morphology, roughness, and wettability of the etched specimens were characterized using optical microscopy, surface profilometry, and water contact angle measurements. The friction and wear characteristics were evaluated using reciprocating sliding tests. The results showed that increasing the etching time led to the development of micro/nanostructures on the surface, thereby increasing surface roughness and hydrophilicity. The friction coefficient initially decreased with increasing surface roughness owing to the reduced contact area but increased during long-term wear owing to the destruction and delamination of surface protrusions. HCl-30M exhibited the lowest average friction coefficient and a balance between the surface roughness and oxide film formation, resulting in improved wear resistance. These findings highlight the importance of controlling the surface roughness and oxide film formation through etching optimization to obtain a uniform and wear-resistant surface for the enhanced durability of 304 stainless steel diaphragms in hydrogen compressors.

• 드라이브 ㆍ 컨트롤
• /
• 제21권2호
• /
• pp.1-7
• /
• 2024

This paper proposes a novel cooling system for hydrogen fuel cell cooling systems by integrating heat pump technology to enhance operational efficiency. The study analyzed the cooling efficiency of the fuel cell cooling system. With the increasing focus on eco-friendly vehicle technologies to address environmental concerns and global warming, the transportation sector, a major contributor to greenhouse gas emissions, needs technological enhancements for better efficiency. The proposed cooling system was modeled through 1-D simulations. The analysis results of parameters such as thermal balance, temperature, and pressure of each component confirmed the stable operation of the system. By examining variations in the cooling system's flow rate, compressor RPM, and the Coefficient of Performance (COP) based on different refrigerants, initial research was conducted to derive optimal operating conditions and parameter values.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2014년도 춘계학술대회
• /
• pp.73-75
• /
• 2014

본 연구는 해상교통안전시설 투자로 인한 해양사고 예방의 경제적 효과를 분석하는 것이다. 안전시설 투자의 경제적 효과 분석을 위해, 조건부 가치측정법을 이용하였다. 조건부 가치측정법은 특정 응답자들을 대상으로 설문지 또는 면접을 통해 환경재와 같은 비시장재의 가치를 계량적으로 측정하기 위해서 사용하는 방법이다. VTS는 시장재가 아니므로 VTS 시설투자에 대한 경제적 타당성을 추정하기 위하여 향후 VTS 시설 설치 예정 지역의 어민 및 선사 등을 대상으로 설문조사를 실시하였다. 설문조사를 실시한 결과, 통역지역 VTS 신설로 인해 발생할 수 있는 연간 총편익은 약110억으로 추정되었다. 2014년부터 5년간 소득세의 형태로 지불하게 된다면, 5년 동안 발생하게 되는 편익은 현재가치 기준으로 약473억원이다. 통영 VTS신설에 따른 경제성 분석결과, 편익-비용비율(B/C ratio)이 3.193로 1보다 높게 나왔고, 순현재가치(NPV)가 325억, 그리고 내부수익률(IRR)이 37.4%로 사회적 할인율인 5.5%보다 높아, 경제적 타당성이 있는 것으로 분석되었다.