• 한국항만경제학회지
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• 제34권1호
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• pp.81-98
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• 2018

우리나라의 경제발전은 무역을 주축으로 하고 있어 항만을 통한 물류가 필수적이다. 항만의 운영과 개발을 위해 막대한 자본과 시간이 투자되고 있으며 항만은 국가 경제 전반에 영향을 미치고 있다. 따라서 사회 경제적 손실을 방지하기 위해선 적정수준의 개발계획이 중요하다. 항만시설 계획은 항만 물동량 예측을 기반으로 수립되므로, 정확한 물동량 예측이 선행되어야 한다. 더불어 항만에서는 품목별로 취급 방식이 다르므로 품목별 예측이 이루어져야 구체적인 시설계획이 가능하다. 따라서 컨테이너 화물이나 항만 전체 물동량에 대해 주로 예측했던 선행 연구들과는 달리 본 논문에서는 전체 물동량에서 큰 비중을 차지하고 있는 유류화물을 분석 대상으로 설정하였다. 단기, 중장기의 주기적 특성과 추세를 갖고 있는 유류화물 물동량을 효율적으로 예측하고자 새로운 예측모형인 TSMR을 개발하였다. TSMR모형의 검증을 위해 기존의 시계열 모형들과 비교분석을 진행하였으며 ARIMA모형의 경우 물동량 데이터가 안정화되지 않아 유효한 결과를 산출할 수 없었다. 윈터스 가법, 단순계절모형과 비교하였을 때 단기적인 예측에는 다소 취약하였으나, TSMR모형의 전반적인 적합도와 예측력은 우수한 것으로 나타났다. 또한 철강, 유연탄, 기계류의 물동량 분석결과 TSMR모형의 일반화 가능성도 충분한 것으로 나타났다.

• 한국항공운항학회지
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• 제29권2호
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• pp.106-110
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• 2021

In this study, the main factors affecting the number of passengers and cargo volume transported by air between Korea, China and Japan over the past 20 years are to be identified. For the analysis, data from three countries' GDP and per capita as well as exchange rates and international oil prices were used, and OLS multiple regression analysis and fixed effect analysis were performed. As a result of the analysis, both the number of passengers and cargo volume transported by air showed a negative (-) direction for GDP, which represents the country's economic power, and a positive (+) direction, for per capita GDP, which represents income level. And the increase in the exchange rate between China and Japan acted in a positive (+) direction on the increase in the number of passengers, and the effect of oil prices was found to be limited.

• 산업경영시스템학회지
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• 제43권4호
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• pp.15-22
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• 2020

Economic indicators are a factor that affects air cargo volume. This study analyzes the different factors affecting air cargo volume by each Chinese cities according to the main characteristics. The purpose of this study is to help companies related to China, airlines, and other stakeholders predict and prepare for the fluctuations in air cargo volume and make optimal decisions. To this end, 20 economic data were used, and the entire data was reduced to 5 dimensions through factor analysis to build a dataset necessary and evaluated the influencing factors by multi regression. The result shows that Macro-Economic Indicators, Production/Service indicators are significant for every cities and Chinese manufacture/Customer indicators, Korean manufacture/Oil Price indicators, Trade/Current indicators are significant for each other city. All adjusted R2 values are high enough to explain our model and the result showed excellent performance in terms of analyzing the different factors which affects air cargo volume. If companies that are currently doing business with China can identify factors affecting China's cargo volume, they can be flexible in response to changes in plans such as plans to enter China, production plans and inventory management, and marketing strategies, which can be of great help in terms of corporate operations.

• 한국컴퓨터정보학회논문지
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• 제28권5호
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• pp.155-161
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• 2023

우리나라 수출의 97.5%, 수입의 87.2%가 해상운송으로 이뤄지며 항만이 한국 경제의 중요한 구성요소이다. 이러한 항만의 효율적인 운영을 위해서는 항만 물동량의 단기 예측을 통해 개선시킬 수가 있으며 과학적인 연구방법이 필요하다. 이전 연구는 주로 장기예측을 기반으로 대규모 인프라투자를 위한 연구에 중점을 두었으며 컨테이너 항만물동량에만 집중한 측면이 크다. 본 연구는 국내 대표적인 석유항만인 울산항의 석유 및 가스화물 물동량에 대한 단기 예측을 수행하였으며 딥러닝 모델인 LSTM(Long Short Term Memory) 모델을 사용하여 RMSE기준으로 예측성능을 확인하였다. 본 연구의 결과는 석유 및 가스화물 물동량 수요 예측의 정확도를 높여 항만 운영의 효율성을 개선하는 근거가 될 수 있을 것으로 기대된다. 또한 기존 연구의 한계로 컨테이너 항만 물동량뿐만 아니라 석유 및 가스화물 물동량 예측에도 LSTM의 활용할 수 있다는 가능성을 확인할 수 있으며 향후 추가 연구를 통해 일반화가 가능할 것으로 기대된다.

• 한국항만경제학회지
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• 제24권2호
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• pp.1-17
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• 2008

본 연구에서는 부산 북항의 장래 물동량을 시계열 모형을 이용하여 정량적으로 예측하였다. 항만물동량을 화물의 특성에 따라 크게 컨테이너, 유류, 일반화물 3가지로 구분하였다. 북항의 물동량 예측에서는 먼저 기존 물동량의 계절지수를 산정하고, 지수평활모형과 ARIMA모형 중에서 최적모형을 선정하였다. 이를 통해 추정된 각 화물별 해당연도의 물동량에 계절지수를 적용하여 물동량을 월별로 산출하였다. 2011년과 2015년의 컨테이너 예측 물동량은 각각 21,390만톤, 23,144만톤이며, 이는 2007년 대비 2011년과 2015년에 각각 약 7.4%, 16.2%로 증가한 것이다. 유류화물의 물동량은 동일하게 약 705만톤으로 2007년 대비 약 4.7% 증가하는 것으로 나타났으나 2002년의 물동량보다는 낮을 것으로 예측되었다. 그리고 일반화물의 물동량은 약 805만톤으로 2007년 대비 2011년과 2015년에 각각 약 0.74%, 0.75% 감소할 것으로 나타나 2007년과 거의 비슷한 수준을 유지할 것으로 예측되었다. 향후 북항에서 처리될 것으로 예측된 전체 항만물동량은 2011년과 2015년에 각각 22,900만톤과 24,654만톤으로 예상되었다. 이는 2007년 대비 각각 약 7.0%, 15.2% 증가한 물동량이다. 이러한 물동량의 증가는 컨테이너화물의 견인차 역할로 인한 결과로 예측되었다. 또한 북항 전체의 장래 월별 물동량을 보면 4월에 가장 많고, 2월에는 가장 적을 것으로 나타났다.

• 한국항해학회지
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• 제11권1호
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• pp.1-38
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• 1987

The amount of cargoes by cargo vessels has increased tremendously during the last decade due to the great growth of korea economy. But in spite of this trend, there is rarely the substantial analyzed on the operational status of coastal shipping. In this paper, the characteristics of seaborne cargo and traffic flow of coastal shipping surveyed in detail through the statistical and the origintain and destination (O.D) analysis. Also, the basic ship's tonnage of coastal shipping representing the minimum tonnage which is capable of carrying the given seaborne cargo is suggested through the computer simulation using the data of 1985 year. The results are as follows; 1) the about 80% of total coastal traffic volume is going in/out to the port of Incheon, Busan, Pohang, Samil, Bukpyung, Mukho, Samchuk, and Jeju. 2) The main cargo items such as oil, iron material, cement, anthracite grain, fertilizer, other ore are reached to the about 70% of total amount of coastal trade. 3) ship's tonnage going in/out to the port of Bukpyiung, Busan, Pohang is increasing linearly year by year, and the amount of oil, iron material, cement, anthracite, grain, fertilizer, other ore are also increasing in linear pattern. 4) As a result of simulation, the optimum (basic) ship's tonnage.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.662-670
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• 2019

Tanker cargo tanks are equipped with the means of raising and maintaining the cargo discharge temperature to a suitable level. In this paper, a new heating coil design is proposed and analyzed. Contrary to conventional designs, wherein the heating coils are evenly distributed over the tank bottom, the proposed design arranges the heating coils in the central part of the tank bottom, in a vertical direction. Due to the intensive cargo circulation generated, a forced convection is superimposed on a buoyancy-driven natural convection, providing a more efficient mixed convection heat transfer mechanism. Numerical simulations performed by using a finite volume method show that in the case of 7-bar steam Bunker C heavy fuel oil heating, a five-hour circulation phase average heat transfer coefficient equals 199.2 W/m²K. This result might be taken as an impetus for the more thorough experimental examination.

• 한국가시화정보학회지
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• 제9권2호
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• pp.54-60
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• 2011

This paper is a basic study on volatile organic compounds(VOC) recovery system in a crude oil carrier. VOC is easily evaporated in cargo tankers during loading and transportation of crude oil, causes serious environmental contamination and a huge economic loss. An ejector system is designed to mix VOC gas into crude oil flow to reduce VOC concentration. Detail two-phase flow inside the ejector is simulated using a commercial CFD code. To verify the numerical prediction, a scale-down experiment is conducted. Instead of crude oil and VOC, water and air are used as the working fluids. Flow characteristics and main parameters are obtained by two-phase flow visualization and PIV measurements. Air volume flow rate induced by the ejector is compared with respect to the volume flow rate of water using experimental and numerical results. Overall performance of the two-phase ejector predicted by the CFD simulation agrees well with that of the experiment.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권1호
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• pp.142-156
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• 2015

A new method for ship Inner Shell optimization, which is called Parametric Inner Shell Optimization Method (PISOM), is presented in this paper in order to improve both hull performance and design efficiency of transport ship. The foundation of PISOM is the parametric Inner Shell Plate (ISP) model, which is a fully-associative model driven by dimensions. A method to create parametric ISP model is proposed, including geometric primitives, geometric constraints, geometric constraint solving etc. The standard optimization procedure of ship ISP optimization based on parametric ISP model is put forward, and an efficient optimization approach for typical transport ship is developed based on this procedure. This approach takes the section area of ISP and the other dominant parameters as variables, while all the design requirements such as propeller immersion, fore bottom wave slap, bridge visibility, longitudinal strength etc, are made constraints. The optimization objective is maximum volume of cargo oil tanker/cargo hold, and the genetic algorithm is used to solve this optimization model. This method is applied to the optimization of a product oil tanker and a bulk carrier, and it is proved to be effective, highly efficient, and engineering practical.

• 한국항해학회지
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• 제7권2호
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• pp.65-113
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• 1983

A lot of studies of ship's economy are on the traditional fields such asreducing propulsion resistance, raising cargo handling rates and lessening building consts, but there are few researches on the merchant ship's economy concerning their deadweights and speeds according to shipping companies managerial cercumstances. Contrary to the contemporary trend that "the bigger, the better, if the cargo handling rate could increased sufficiently to hold down port time to that rate of smmaler vessels", this paper demonstrates the existence of certain limits in ship's size and speed according to the coditions of the freight rates, voyage distances, cargo handing rates, prices of fuel oil, interst rates etc. Fom the curves of criteria contour for various ship's deadweights and speeds which are depicted from the gird search method, one can get the costs and the yearly profit rates under the conditiions of large volume with long term contracts for the transportation of bulk cargoes. In estimating ship's transportation economy, the auther takes the position that the profit rate method is properer than the cost method, and introduces the calculation table of the voyage profit rate index. The use of the criteria contours will be of help to ship owners in determining the size and speed of the ship which will be built or purchased and serve in a certain trade route.