The Comparative Analysis on the Scrap Transport Costs of Container and Bulk Ship

철강산업은 자동차, 조선, 기계, 건설, 방위산업을 비롯한 전 산업의 기초소재를 제공하는 산업으로 매우 중요한 산업이다. 우리나라는 주요 철강생산 강국으로 세계 조강 생산 중 국내에서 생산되는 조강생산 비중은 1970년 0.1%에서 1995년도 4.9%로 급격히 증가, 2000년도에서 2007년도 사이에는 대략 4~5%를 점유하고 있으며, 철강재의 지속적인 수출은 무역수지 개선에 크게 기여하고 있다. 그러나 우리나라의 경우 철강산업 원자재의 대부분을 수입에 의존하고 있는 실정이며, 이때 원료의 중량이 무겁기 때문에 수송비 부담이 매우 크다. 따라서 철강산업은 원자재의 안정적인 공급과 원자재의 운송 시 발생하는 물류비용의 효율적인 관리가 매우 중요하다 할 수 있다. 따라서 본 연구에서는 철스크랩 화물의 수송합리화를 위한 운송경로별 경제성을 컨테이너선 운송과 벌크선 운송의 운송비 및 물류비의 비교·분석을 통하여 고찰해 보고자한다.The steel industry, as the national representative strategic industry of our country, has played the motive power for the economic growth of Korea in 1970s as the positive support of the government and the management endeavor of the private were harmonized. However, in case of our country, we have mostly relied on import of the raw materials for the steel industry, and as the weight of the imported raw materials is heavy, the steel industry is the industry whose transport burden is big as it is called ‘transport industry’. So, the transport rationalization will be the important task of the steel industry. So, this study has analyzed the economic efficiency per the transport route (container ship vs bulk ship) of the sea transport related to import/export of the steel scrap on the level acquiring the stable supply of the steel scrap. For this, this study firstly researched the status of domestic/foreign steel industry and analyzed the world crude steel production volume, steel scrap consumption volume and world steel scrap trading structure. Also, in order to compare the transport logistics expenses between two transport devices, namely, container ship and bulk ship, related to import/export of annual world crude steel scrap, this study calculated the logistics expenses per ton by using the traffic hours and traffic expenses items as the imported/exported steel scrap freights between Korea and USA, and between Korea and China of ‘D’ company, which is the import/export company of steel scrap, become the objectives. As per the analysis results of the transport logistics expenses through the routes of the container ship and bulk ship, as for the steel scrap transport line between Korea and USA, firstly, the logistics expenses through the bulk ship from 2002 to 2006 is shown economical, and as for the period from 2007 to 2008, the time when the irregularity market status reached the maximum, the logistics expenses through the container line is shown economical. And it was expected that as for the transport logistics expenses per each container of the container liner between Korea and USA, 40ft dry container was more economical than that of 20ft, but it has been appeared that 20ft is more economical than 40ft in the logistics expenses per ton. So, it has been decided that as for the export/import transport route of the steel scrap between Korea and USA, it is more proper to be transported through the transport device of the bulk ship rather than the container ship, but that in case the transport logistics expenses of the bulk ship is higher than that of the container ship as per the tramper market status, it is more proper to transported through the container ship. And, in case the steel scrap freight is transported through the container ship, it was efficient decision-making to use 20ft dry container than 40ft dry container.제1장 서론 = 1 제1절 연구의 필요성과 목적 = 1 제2절 연구방법 및 구성 = 3 제2장 이론적 배경 = 5 제3장 철강산업의 현황 = 11 제1절 철강산업의 개념과 특성 = 11 제2절 세계 철강산업의 현황 = 12 제3절 국내 철강산업의 현황 = 17 제4장 철 스크랩화물의 운송현황 = 20 제1절 철 스크랩의 개념 = 20 제2절 국내외 철 스크랩의 교역구조 = 22 제3절 국내의 철 스크랩 유통구조 = 27 제4절 스크랩 화물의 수출입 절차 = 29 제5장 철 스크랩 화물의 운송경로별 경제성 평가 = 36 제1절 한-미간 철 스크랩 해상운송을 통한 물류비용 = 36 제2절 한-중간 철 스크랩 해상운송을 통한 물류비용 = 41 제3절 철 스크랩 화물의 해상운송 수단별 경제성 평가 = 46 제6장 스크랩 화물의 효율적인 해상운송 방안 = 53 제1절 최적 운송경로의 선택 = 53 제2절 경제적 환경 변화에 대한 대응 = 55 제7장 결론 = 57 제1절 결론 및 연구요약 = 57 제2절 연구의 의의 및 한계 = 59 참고문헌 = 6

공개키 기반구조에서의 인증서 연구

학위논문(석사) - 한국정보통신대학원대학교 : 공학부, 2002, [ viii, 45 p. ]The Public Key Infrastructure (PKI) and Wireless PKI(WPKI) are essential to many kinds of electronic businesses through the Internet. A certificate and related mechanism such as the Certificate Revocation List (CRL), and the certificate path validation are important components in PKI and WPKI. However, because a certificate does not contain its full path, a verifier must check the certificate revocation status and perform the certificate path validation, step by step. Even though a verifier finished to check the certificate revocation status and perform the certificate path validation, a verifier can only know the probabilistic answer about thaget certificate, because a CRL is published in every periodic time. In this thesis, we will propose two schemes. One is a new approach of X.509v3 certificate for full path validation. Using our proposal scheme, we can reduce the time complexity of the certificate path validation from $\emph{O(n)}$ to $\emph{O(n)}$, when $\emph{n}$ is the size of the certificate full path. In addition, using our proposed scheme, we will show an application, the Online Certificate Verification Protocol(OCVP), which requires neither the CRL mechanism nor a new trusted server. With respect to the computational load, the loads in OCVP is $\emph{2n}$ which the same in the Simple Certificate Validation Protocol (SVCP). However, SCVP uses the CRL mechanism and a new trusted server, and gives us a probabilistic answer. But, OCVP uses all CAs who are located on the certification full path and gives us an exact answer. The other can be considered as one of alternatives for CRL, a CA live list (write CAL). The point of our proposed concept is that for CA``s certificate we manage a live list in the place of a revoked list. In the ordinary case, we must check the certificate revocation status and perform the certificate path validation. However, using CAL, we only check the CA live status. Therefore, in the certificate path validation, we reduce...한국정보통신대학원대학교 : 공학부