• Resources Recycling
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• v.23 no.6
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• pp.63-67
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• 2014

Gallium is an important material and is used by industry of oxide semi-conductor and LED chip. However, the most of the gallium-containing waste resources became outflow abroad and the most of which is imported from oversea by following technical problem and low circulation rate. In this research, the recovery of high purity Gallium metal from Gallium scrap, which containing about 30% of Gallium, was investigated by using hydro-metallurgical process. As pretreatment, the Gallium scrap was pulverized and leached by strong acid such as hydro chloric acid. At the leached solution, Indium was separated as an Indium sponge by substitution reaction and then Gallium and Zinc hydroxide separated and filtrated using strong alkaline solution such as sodium hydroxide by precipitation method. Also, Gallium metal and Zinc metal was recovered by electrowinning method. To make an electrolytic solution, Gallium and Zinc hydroxide was leached by strong alkaline solution. Finally, High purity Gallium metal was recovered by vacuum refining process to remove the Zinc impurity.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.403-408
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• 2007

The purpose of this paper is to show a way for measuring the rankings of efficient seaports in Korea by using DEA(data envelopment analysis) and model suggested by Jahanshahloo et al(2006). Two inputs(birthing capacity, and cargo handling capacity) and three outputs(export cargo handling amount, import cargo handling amount, and number of ship calls), and one cross sectional data(2004) for 26 Korean seaports are considered for measuring the efficiencies. An empirical main result indicates that ranking order of efficient seaports are Okpo, Samcheok Ulsan, Daesan, Busan, Gohyun Ports. Samcheok Port is classified as the most strong efficient port among 16 general ports except 10 container ports. The Korean seaport authority can adopt the new measurement way introduced in this paper for measuring the exact ranking order of efficient seaports when it decides the development and investment to each efficient seaport.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.815-825
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• 2016

The inter-industrial inducement effects of the Korean railway services on the output, value-added, and imports of 383 industrial sectors of the Korean economy have been computed by the input-output analysis technique utilizing the '2013 Input-Output Statistics', which was published most recently in December 2015 by the Bank of Korea. The research results are, then, compared and contrasted with the former research results with the '2003 Input-0utput Statistics', which were published in the Journal of the Korean Society for Railway, August, 2008. The economic inducement effects computed in this study are as follows. The Korean railway service industry produced \5,841 billion worth of passenger and freight railroad services in the year 2013, and it induced \8,511 billion worth of output, \84 billion worth of value-added, and \1,050 billion worth of imports for Korean industry as a whole.; the production inducement multiplier, value-added multiplier, and imports inducement multiplier of 2013 results are shown to be quite different from 2003 multipliers.; it has been shown that it is necessary to utilize the most recent Input-Output Statistics for the computation of the most recent inter-industrial analysis.

• Journal of the Korean Regional Science Association
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• v.35 no.1
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• pp.47-57
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• 2019

Daegu Metropolitan City has been continuously carrying out core functions of Yeongnam region, and especially plays a role as export base of textile and chemical products in Korea. Also Daegu Metropolitan City has contributed greatly to the expansion of Korea's import and export trade and the growth of the national economy. The purpose of this study is to analyze the influence of major factors affecting GRDP in Daegu Metropolitan City through regression analysis. For this purpose, this study uses the Vector Error Correction Model(VECM) to estimate the long-run equilibrium function that affects the GRDP in Daegu Metropolitan City. This study is meaningful in that it uses the statistics related to Daegu provided by Province of Gyeongsangbuk-do and explains the dynamic characteristics of major factors affecting the GRDP in Daegu.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.7
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• pp.283-290
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• 2022

Blockchain is a technology that secures integrity and transparency by distributing and storing transaction details within multiple node networks. Recently, research is being conducted to secure integrity by applying blockchain to Bill of Lading (B/L documents) of monetary value. In this paper, we study a blockchain-based bill of lading system to improve usability. The shippers register the issued bill of lading on the blockchain, and banks in each country read it to conduct L/C transactions. The consignees receive the goods after completing certification with a quick response code (QR) containing the bill of lading information. Through this, shippers enjoy merits in that they can shorten the time and cost of sending shipping documents by mail and prove the integrity of the documents. The consignees have the advantage of being able to check the documents at the same time as they are registered and trust the transaction. Finally, on the bank side, the security of shipping documents is ensured and verification can be done quickly.

• Korea Trade Review
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• v.48 no.2
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• pp.153-174
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• 2023

Electronic bill of lading, Letter of Guarantee, Surrender B/L, Seaway Bill, etc. have been proposed as alternative tools to overcome the crisis of bill of lading, but the most useful of these is by far the Surrender B/L. However, since the Surrender B/L has various problems due to the absence of a legal basis, studies so far have been conducted focusing on these legal limitations or problems in use of the Surrender B/L. This study tried to empirically identify the factors that affect the spread of Surrender B/L by expanding this point of research view. A hierarchical regression analysis was conducted by acquiring 190 valid samples centered on member companies of the Korea International Freight Forwarders Association. In addition, the R program was used to diagnose the research data and analyze the degree of spread by region. As a result of the empirical analysis, it was found that the utilization of Surrender B/L increased due to the convenience and cost reduction effect of Surrender B/L and the apprenticeship training of forwarding companies. In addition, as a result of regional analysis, the spread of Surrender B/L was notable not only in neighboring regions but also even in areas far from Korea.

• Resources Recycling
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• v.24 no.2
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• pp.23-28
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• 2015

Most of the domestic need for tin rely on imports. In this work, a pyrometallurgical process was investigated to recover pure tin from the tin oxides in tin bath which results from the production of flat glass and LCD panel. From the results on the effect of reaction temperature, the highest recovery percentage of tin was obtained at $1350^{\circ}C$. The recovery percentage of tin was improved to 88% by employing the first and second smelting step. Electrorefining of the crude tin thus obtained led to pure tin with purity higher than 99.9%.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.129-136
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• 2023

In this paper, we describe a rule-based risk classification algorithm to perform Risk-based Inspection (RBI) on imported goods at customs. The RBI system is a method to automatically select which cargos have to be inspected and manage potential risks in boarder. In this study, we designed a rule-based risk classification algorithm for RBI solutions and implemented them using the Svelte web application framework. The risk classification algorithm proposed in this paper uses different indicative risk factors such as HS code, country of origin, importer's reliability, trade relationships, and logistics routes to classify cargos into Green, Yellow, and Red channels. To achieve this, we assigned risk categories to each risk factor and randomly generated risk scores within a specific range for each risk category. This system is expected to contribute to the increased efficiency of customs operations and protect public safety by minimizing the risk of imported hazardous materials.

• Journal of Korea Port Economic Association
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• v.34 no.1
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• pp.111-132
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• 2018

As China continues to evolve as a major economic power and the Free Trade Agreement (FTA) between the Republic of Korea and China was ratified on June 1, 2015, market volume between the two countries is expected to grow more rapidly. This study aims on improving the efficiency of car-ferry lines. We conducted two surveys- for shippers and forwarders of car-ferry companies, and container liners. The study analyzes the decision factors for delivery companies and their importance for shippers and forwarders of car-ferry companies and container liners. Based on analysis of prior studies on the competition for car-ferry companies and liners, three primary variables are selected-promptness, economics, and safety. The promptness variable consists of shipping time, loading/unloading time, and customs clearing time. The economic variable consists of marine transportation cost from a domestic harbor to China, loading/unloading cost in the harbor, and overland transport cost from the harbor to shippers inland. Finally, the safety variable consists of cargo damage rates, safety facilities, such as lashing and shoring, and punctuality of transportation time. The survey and AHP results show that the promptness, safety, and economics factors are 0.549, 0.309, and 0.142 in the shipper groups of car-ferry companies' category, respectively. It indicates that there is considerable difference in the importance of each factor. In contrast, the factors are 0.350, 0.348, and 0.302 in the forwarders category, which suggests that there is little difference in each factor's importance. As for shippers and forwarders of liners, the importance of each factor is found to be in the following order: economics, safety, and promptness.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.441-451
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• 2000

Sludge produced from water treatment plants contains plenty of aluminum due to addition of coagulants, polyaluminum chloride(PACI) which has been widely used in most of water treatment plants. however. the whole of PACI is imported from other countries. In this research. the effective methods for recycling PACI from sludge of water treatment plants were developed and evaluated. Aluminum chloride hexahydrate($AlCl_3{\cdot}6H_2O$) was obtained by sparging HCl gas aluminum extracted from sludge using hydrochloric acid (HCI). This aluminum chloride hexahydrate was solidified by decomposition at $180^{\circ}C$. and dissolved in water to produce PACI. The optimum extraction rate was obtained at the condition of 10 minutes of reaction time. $105^{\circ}C$ of reaction temperature. 27.65%(W/W) of HCI concentration. The KS experiment proved that manufactured aluminum chloride hexahydrate was 98.7% degree and the recycled PACI coagulants agreed with the KS standard. The optimum temperature of decomposition was $180^{\circ}C$ and the basicity of the PACI was decided upon the extent of decomposition The compared experiments between purchased coagulant and manufactured coagulant presented that both coagulants had same performance for turbidity, DOC, $UV_{254}$ absorbance. and chlorophyll-a.