• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.357-367
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• 2015

This study aims to propose integrated management strategies based on the relationship between co-benefits and total benefits of greenhouse gases and air pollutant emissions for establishing a transport and environmental policy. The results show that the integrated management of the following policies: 'Car Free Day' and 'Early Scrapping of Decrepit Diesel Vehicle', which are used for reducing reduce gasoline and diesel, can together reduce both PM and $CO_2$ emissions and increase total benefits. In addition, the integrated management of 'Car Free Day' with environment policies and 'Congestion Charge' with environment policies simultaneously controls the three factors which influence emissions, including travel volume, travel speed and emissions factor, and was found to be effective in terms of co-benefits. This study reduces both air pollutants, which are harmful to health, and greenhouse gas emissions, which influence climate change, and improves the efficiency of policy through the integrated management of policies.

• Environmental and Resource Economics Review
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• v.16 no.3
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• pp.575-605
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• 2007

Korea's tidelands policy IS examined and criticized in the paper. Korea's major tidelands in the west coast might disappear within a decade. The anachronistic development IS driven by the political interest group, forming coalition for reclamation and busily fulfilling its own profits under the facade of public good and regional development. But all regions of the world have been gradually scrapping the massive reclamation projects since the 1970's and active movements to reverse the reclamation and restore the nature are on the rise. In 1978, the U.S. Supreme Court decided to suspend the construction of the dam and to protect the snail darter despite that over 100 million dollars had been injected. This court ruling became famous and caused the American public to change their perception about the environment. In the Netherlands, following a prolonged discussion on pros and cons of reclamation, open type seawall was adopted to strike a balance among the available alternatives. Japan's Ministry of Environment was praised for forming the National Wetland Committee in order to designate 20 new Ramsar sites by 2008, with an objective to reach 33 designated Ramsar sites. Away from the large-scale reclamation projects, Korea has to move towards smaller-scale projects focusing on the knowledege intensive and circular economy society that are more in harmony with the environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.693-702
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• 2009

In the Seoul metropolitan area (SMA), transportation sector is the largest source of air pollutant emissions. Of the total amount of air pollutant emissions in the SMA, about 52% of the particulate matter emissions and 59% of the nitrogen oxide emissions are from superannuated heavy diesel vehicles. To lessen the air pollutant emissions from superannuated heavy vehicles in the SMA, this study devised several strategies for operating Environmental Zone (EZ) program, which requires superannuated heavy diesel vehicles to install reduction equipments as well as restricts them entering part of the SMA, and evaluated the effects of different strategies on air pollution in the SMA. By using the Korean traffic statistics, an evaluation has been made of six EZ scenarios, which were devised by different target areas and vehicles. The results showed that the EZ program with retrofitting a DPF (Diesel Particulate Filter) equipment to 7-year-old heavy diesel vehicles and early scrapping of pre-1998 heavy diesel vehicles is the most efficient alternative in terms of air pollution reduction. In addition, the results showed that the magnitude of air pollution reduction increases when implementing the EZ program to all entering superannuated heavy diesel vehicles to the SMA rather than registered ones in the SMA.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.208-222
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• 2023

With the recent revision of 「Act on Promotion of the Transportation Convenience of Mobility Disadvantaged Persons」 and the Enforcement Regulations of the Act, bus business operators must introduce low-floor buses when scrapping buses. On the other hand, in the case of routes where low-floor buses cannot be operated, bus business operators can be exempted from introducing low-floor buses with the approval of their transportation administrative agency according to Article 4-2 of 「Enforcement Regulation of the Act on Promotion of the Transportation Convenience of Mobility Disadvantaged Persons」. According to the data from the Korea Bus Transportation Associations Federation, approximately 5.9% of all city bus routes were surveyed as the exceptions to introducing low-floor buses. Nevertheless the proportion is expected to increase because some regions with difficulties introducing low-floor buses are not included when calculating the proportion. By confirming the process of approving exceptions for introducing low-floor buses through local governments, there was no specific examination method or standard for approval of exceptions. Hence, there is the problem that some routes are approved as exceptions to introducing low-floor buses, even though low-floor buses can be operated on those routes. Therefore, this study aims to develop a manual that can objectively diagnose the overall operation environment of low-floor buses, such as road geometry and road facilities. Future research plans to apply it to more cases and improve it for more precise application in various contexts.

• Journal of Navigation and Port Research
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• v.48 no.1
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• pp.62-77
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• 2024

In the maritime shipping industry, imbalance between supply and demand has persistently increased, leading to the utilization of blank sailings by major shipping companies worldwide as a key means of flexibly adjusting vessel capacity in response to shipping market conditions. Traditionally, blank sailings have been frequently implemented around the Chinese New Year period. However, due to unique circumstances such as the global pandemic starting in 2020 and trade tensions between the United States and China, shipping companies have recently conducted larger-scale blank sailings compared to the past. As blank sailings directly impact freight transport delays, they can have negative repercussions from perspectives of both businesses and consumers. Therefore, this study employed Poisson regression models and negative binomial regression models to analyze the influence of maritime freight rate determinants on shipping companies' decisions regarding blank sailings, aiming to proactively address potential consequences. Results of the analysis indicated that, in Poisson regression analysis for 2M, significant variables included global container shipping volume, container vessel capacity, container ship scrapping volume, container ship newbuilding index, and OECD inflation. In negative binomial regression analysis, ocean alliance showed significance with global container shipping volume and container ship order volume, the alliance with container ship capacity and interest rates, non-alliance with international oil prices, global supply chain pressure index, container ship capacity, OECD inflation, and total alliance with container ship capacity and interest rates.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.243-254
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• 2023

This study investigates the factors contributing to price fluctuations in the shipscrapping market, the final stage in a vessel's life cycle. Shipping companies make decisions on ship dismantling based on factors such as declining freight rates, increasing vessel age leading to higher costs, or compliance with new environmental regulations. Utilizing the FMOLS (Fully Modified Ordinary Least Squares) and VECM (Vector Error Correction Model) methodologies, the research explores the long-term elasticities of factors influencing shipscrapping prices and examines short-term causal relationships. Using a time series dataset spanning from December 2015 to April 2023, covering a total of 90 months, the study focuses on the shipscrapping prices of Capesize vessels in India and Bangladesh, which constitute a significant portion of the shipbreaking market. The findings indicate that, in the long term, shipscrapping prices are closely related to global scrap prices, 20-year-old secondhand Capesize vessel prices, newbuilding prices, and exchange rates. In terms of short-term causal relationships, an increase in global scrap prices induces a rise in shipscrapping prices, while the remaining variables do not contribute to such increases. Specifically, an escalation in shipscrapping prices is associated with increased prices of 20-year-old secondhand vessels, newbuilding prices, and exchange rates. However, the other variables do not show a significant influence on short-term increases in shipscrapping prices.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.103-109
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• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• Journal of Intelligence and Information Systems
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• v.19 no.1
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• pp.95-110
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• 2013

Recently, the amount of unstructured data being generated through a variety of social media has been increasing rapidly, resulting in the increasing need to collect, store, search for, analyze, and visualize this data. This kind of data cannot be handled appropriately by using the traditional methodologies usually used for analyzing structured data because of its vast volume and unstructured nature. In this situation, many attempts are being made to analyze unstructured data such as text files and log files through various commercial or noncommercial analytical tools. Among the various contemporary issues dealt with in the literature of unstructured text data analysis, the concepts and techniques of opinion mining have been attracting much attention from pioneer researchers and business practitioners. Opinion mining or sentiment analysis refers to a series of processes that analyze participants' opinions, sentiments, evaluations, attitudes, and emotions about selected products, services, organizations, social issues, and so on. In other words, many attempts based on various opinion mining techniques are being made to resolve complicated issues that could not have otherwise been solved by existing traditional approaches. One of the most representative attempts using the opinion mining technique may be the recent research that proposed an intelligent model for predicting the direction of the stock index. This model works mainly on the basis of opinions extracted from an overwhelming number of economic news repots. News content published on various media is obviously a traditional example of unstructured text data. Every day, a large volume of new content is created, digitalized, and subsequently distributed to us via online or offline channels. Many studies have revealed that we make better decisions on political, economic, and social issues by analyzing news and other related information. In this sense, we expect to predict the fluctuation of stock markets partly by analyzing the relationship between economic news reports and the pattern of stock prices. So far, in the literature on opinion mining, most studies including ours have utilized a sentiment dictionary to elicit sentiment polarity or sentiment value from a large number of documents. A sentiment dictionary consists of pairs of selected words and their sentiment values. Sentiment classifiers refer to the dictionary to formulate the sentiment polarity of words, sentences in a document, and the whole document. However, most traditional approaches have common limitations in that they do not consider the flexibility of sentiment polarity, that is, the sentiment polarity or sentiment value of a word is fixed and cannot be changed in a traditional sentiment dictionary. In the real world, however, the sentiment polarity of a word can vary depending on the time, situation, and purpose of the analysis. It can also be contradictory in nature. The flexibility of sentiment polarity motivated us to conduct this study. In this paper, we have stated that sentiment polarity should be assigned, not merely on the basis of the inherent meaning of a word but on the basis of its ad hoc meaning within a particular context. To implement our idea, we presented an intelligent investment decision-support model based on opinion mining that performs the scrapping and parsing of massive volumes of economic news on the web, tags sentiment words, classifies sentiment polarity of the news, and finally predicts the direction of the next day's stock index. In addition, we applied a domain-specific sentiment dictionary instead of a general purpose one to classify each piece of news as either positive or negative. For the purpose of performance evaluation, we performed intensive experiments and investigated the prediction accuracy of our model. For the experiments to predict the direction of the stock index, we gathered and analyzed 1,072 articles about stock markets published by "M" and "E" media between July 2011 and September 2011.