• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.21-35
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• 2022

With the support of local and central governments, various incentive policies for "green" cars have been established, and the number of electric vehicle users has been rapidly increasing in recent years. As a result, much attention is being given to establishing a user-centered charging infrastructure. A standard for the number of electric vehicle chargers to be supplied is being prepared based on building characteristics, but there is quite limited research on the appropriate ratio of slow and fast chargers based on the characteristics of each place. Therefore, this study derived an appropriate penetration ratio based on data about the distribution ratio of common slow chargers. These data were collected using a survey of actual electric vehicle users. Next, an analysis was done on how to categorize the needs of charging environments and to determine what criteria or characteristics to use for categorization. Based on the results of the survey analysis, three types of places were derived. Type-1 places require 10% of chargers to be slow chargers, Type-2 places require 40-60% of chargers to be slow chargers (i.e., around equal distribution of slow and fast chargers), and Type-3 places require more than 80% of chargers to be slow chargers. The required levels of slow chargers were classified by place type and by individual using latent class cluster analysis, which made it possible to categorize them into five clusters related to socioeconomic variables, vehicle characteristics, traffic, and charging behaviors. It was found that there was a high correlation between charging behavior, weekend travel behavior, gender, and income. The results and insights from this study could be used to establish charging infrastructure policies in the future and to prepare standards for supplying charging infrastructure according to changes in the electric vehicle market.

• Journal of Intelligence and Information Systems
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• v.23 no.2
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• pp.107-122
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• 2017

Volatility in the stock market returns is a measure of investment risk. It plays a central role in portfolio optimization, asset pricing and risk management as well as most theoretical financial models. Engle(1982) presented a pioneering paper on the stock market volatility that explains the time-variant characteristics embedded in the stock market return volatility. His model, Autoregressive Conditional Heteroscedasticity (ARCH), was generalized by Bollerslev(1986) as GARCH models. Empirical studies have shown that GARCH models describes well the fat-tailed return distributions and volatility clustering phenomenon appearing in stock prices. The parameters of the GARCH models are generally estimated by the maximum likelihood estimation (MLE) based on the standard normal density. But, since 1987 Black Monday, the stock market prices have become very complex and shown a lot of noisy terms. Recent studies start to apply artificial intelligent approach in estimating the GARCH parameters as a substitute for the MLE. The paper presents SVR-based GARCH process and compares with MLE-based GARCH process to estimate the parameters of GARCH models which are known to well forecast stock market volatility. Kernel functions used in SVR estimation process are linear, polynomial and radial. We analyzed the suggested models with KOSPI 200 Index. This index is constituted by 200 blue chip stocks listed in the Korea Exchange. We sampled KOSPI 200 daily closing values from 2010 to 2015. Sample observations are 1487 days. We used 1187 days to train the suggested GARCH models and the remaining 300 days were used as testing data. First, symmetric and asymmetric GARCH models are estimated by MLE. We forecasted KOSPI 200 Index return volatility and the statistical metric MSE shows better results for the asymmetric GARCH models such as E-GARCH or GJR-GARCH. This is consistent with the documented non-normal return distribution characteristics with fat-tail and leptokurtosis. Compared with MLE estimation process, SVR-based GARCH models outperform the MLE methodology in KOSPI 200 Index return volatility forecasting. Polynomial kernel function shows exceptionally lower forecasting accuracy. We suggested Intelligent Volatility Trading System (IVTS) that utilizes the forecasted volatility results. IVTS entry rules are as follows. If forecasted tomorrow volatility will increase then buy volatility today. If forecasted tomorrow volatility will decrease then sell volatility today. If forecasted volatility direction does not change we hold the existing buy or sell positions. IVTS is assumed to buy and sell historical volatility values. This is somewhat unreal because we cannot trade historical volatility values themselves. But our simulation results are meaningful since the Korea Exchange introduced volatility futures contract that traders can trade since November 2014. The trading systems with SVR-based GARCH models show higher returns than MLE-based GARCH in the testing period. And trading profitable percentages of MLE-based GARCH IVTS models range from 47.5% to 50.0%, trading profitable percentages of SVR-based GARCH IVTS models range from 51.8% to 59.7%. MLE-based symmetric S-GARCH shows +150.2% return and SVR-based symmetric S-GARCH shows +526.4% return. MLE-based asymmetric E-GARCH shows -72% return and SVR-based asymmetric E-GARCH shows +245.6% return. MLE-based asymmetric GJR-GARCH shows -98.7% return and SVR-based asymmetric GJR-GARCH shows +126.3% return. Linear kernel function shows higher trading returns than radial kernel function. Best performance of SVR-based IVTS is +526.4% and that of MLE-based IVTS is +150.2%. SVR-based GARCH IVTS shows higher trading frequency. This study has some limitations. Our models are solely based on SVR. Other artificial intelligence models are needed to search for better performance. We do not consider costs incurred in the trading process including brokerage commissions and slippage costs. IVTS trading performance is unreal since we use historical volatility values as trading objects. The exact forecasting of stock market volatility is essential in the real trading as well as asset pricing models. Further studies on other machine learning-based GARCH models can give better information for the stock market investors.

• Clinical and Experimental Pediatrics
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• v.49 no.1
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• pp.24-28
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• 2006

Purpose : The purpose of this study was to investigate the health status and nutritional condition of children living in a low-income community through anthropometric, laboratory evaluation. Methods : A community-based survey identified children below 15 years living in a low-income community. Their weight, height, visual acuity, hearing level and dental status were measured. Blood sample were obtained on June and July, 2004. Hemoglobin, serum cholesterol, Hepatitis B antigen/antibody, AST and ALT were measured. Results : A total of 285 students(M : F=141 : 144) aged 6 to 14 years were included in this study. The heights and weights in some grades were smaller than controls. The prevalence of obesity was 10.6 percent in males and 10.7 percent in females. The prevalence of abnormal visual acuity, hearing impairments and dental carries were 20.5 percent, 0.3 percent and 69.4 percent. The prevalence of anemia was 10.1 percent. Serum total cholesterol was over 200 mg/dL in 7 percent. They complained of abdominal pain(22.1 percent) and headache(17.1 percent). Hyperthyroidism, cataract, neurofibromatosis, severe atopic dermatitis, ventricular septal defect, strabismus and inguinal hernia were newly diagnosed. Conclusion : Mean heights and weights of children in the low-income community were smaller than controls. The prevalence of abnormal visual acuity, hearing impairment and dental carries were higher than in the 2003 national health survey. Additional research is needed to evaluate the health status of the low-income community.

• Journal of the Korean Geographical Society
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• v.50 no.3
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• pp.255-276
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• 2015

This paper presents a multi-agent system model of land-use and cover changes, which is developed and applied to the Gariwang-san and its vicinity, located in Pyeongchang and Jeongseon-gun, Gangwon province, Korea. The Land Use Dynamics Simulator (LUDAS) framework of this study is well suited for representing the spatial heterogeneity and dynamic interactions between human and natural environment, and capturing the impacts of forest-opening policy interventions to future socio-economic and natural environment changes. The model consists of four components: (1) a system of human population, (2) a system of landscape environment, (3) decision-making procedures integrating human(or household), environmental and policy information into forest land-use decisions, and (4) a set of policy scenarios that are related to the forest-opening. The results of model simulation by different combination of various forest management scenarios are assessed by the levels of household income, ecosystem service value and income inequality in the study region. As a result, the optimal scenario of forest-opening policies in the study region is to open the forest to local residential community for the purpose of recreation, considering the distinctive topographical feature. The model developed in this research is expected to contribute to a decision support system for sustainable forest management and various land-use policies in Korea.

• Journal of Technology Innovation
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• v.25 no.2
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• pp.153-179
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• 2017

Korean government has granted fixed indirect cost rates to several exceptional R&D programs which is lower than the predetermined rate by the government. It has been needed to evaluate the validity of exceptional R&D programs and determine the optimal indirect costs rate of the programs. This study analyzes the cost structure and explores drivers of indirect costs of exceptional R&D programs and evaluates the validity of current indirect costs rates. Finally, we propose the formulas for indirect costs rates of exceptional R&D programs. We analyze the cost structure of the exceptional R&D programs. Equipments and material costs are 50% in infra building program. Scholarship to students is 43% in HRD program. Equipments and material costs are 50% and R&D activity costs are 31% in international R&D program. Main cost components of evaluation program are salary(37%), R&D execution costs(21%) and R&D activity costs(19%). We propose three formulas of indirect costs for exceptional programs. 1) The cost items with exceptionally large amount are excluded in the base of formula for indirect costs. 2) Fixed indirect cost rate is applied for specific R&D programs. 3) Upper bound is set for the cost items with exceptionally large amount in the calculation of indirect costs rate. Our proposal is expected to contribute to the improvement of the efficiency of national R&D programs.

• Korean Journal of Heritage: History & Science
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• v.53 no.3
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• pp.110-127
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• 2020

The term "conserved remains" refers to cultural remains that are preserved in accordance with the valuation of buried cultural properties when important remains are recognized in rescue excavations during construction work. South Korea's rapid economic growth and ensuing land development over the past few decades compelled a sharp increase in the number of rescue excavation cases, and, naturally, of conserved remains. Today, an increasingly large number of conserved remains have raised issues, including those concerning land expropriation as well as the management and utilization of such remains, but no clear solutions have been proposed. This study attempts to propose plans for improvement based mainly on the recognition of institutional issues rather than technical issues related to the conservation of cultural remains. This is because the identification and review of institutional deficiencies must be prioritized in order to efficiently manage conserved remains with limited resources and manpower. Among many possible proposals to demand improvement of conservation policies, one that must first be examined under the current system is the rapid transition, or review thereof, of "conserved remains" to "designated cultural properties." Unlike designated cultural properties, conserved remains are merely a temporary means of conservation, because they lack regulations for follow-ups subsequent to preliminary measures. Naturally, deferring the definition of relics as "conserved remains" for extended periods causes numerous problems. Measures to resolve such problems may include establishing a legal system to manage conserved remains at a level similar to designated cultural properties or seeking ways to improve management under the current system. This study focuses on areas where institutional improvement for conserved remains is possible by methods other than through the rapid transition to designated cultural properties and presents several proposals. Currently, conservation measures are divided into three categories: on-site conservation, relocation conservation, and record conservation. This study reclassifies these categories from three into four categories. On-site conservation includes only two categories: conserved remains and the newly-proposed soil-covered remains. Two remaining categories, the relocation conservation remains and the record conservation remains, are presented as classifications in which development projects are possible, and they are presented as alternative conservation types that contrast with on-site conservation. Unlike conserved remains, soil-covered conservation presented as a new category in which development projects are possible.

• Cartoon and Animation Studies
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• s.32
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• pp.189-220
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• 2013

It is expected that interests and supports for 'the creative economy' will increase considerably since the establishment of the Park Geun Hye Administration. According to a report with respect to its cultural policy handed in by the Minister of Culture to the president on March 28, 2013, the administration will set up a basic plan of establishing regional fusion-typed laboratories including such genres as story telling, animations, games, cartoons, performances, etc. in May this year, and opening contents Korea laboratories across the country by the first quarter in 2014 as part of its core task. Furthermore, it will focus on implementing such policies for training professional manpower as creative mentoring programs, expansion of education for field employees and expansion of a creative education for young students, including a plan to train 1,000 creative contents talents by 2017 as described in the report. Since the Comics Promotional Law took effect in August 2012, the Korea Culture and Content Agency and the Comics Industry have been establishing the third plan for medium and long term development of the comics industry together. One of the most important policy is about training professional manpower. "Joint Business with Creative Talents," in which the amount of 4.5 billion won was invested, has already been implemented, and "Support Business for Field Employees of Comics Creating Enterprises," in which the amount of 0.6 billion won was invested, has been performed so far through the Korea Comics Contents Agency upon the request of the Comics Industry. The government's plan to train professional manpower is interlocked with its foundation and employment policies, and thus, this will be a good opportunity for colleges and universities that have comics related majors, especially for those that need proper measures for bring their graduates a chance to get a job. Accordingly, it seems that if the government develops more aggressive policies, reflects this on the third medium and long term development plan of the comics industry, and then organizes policy and study meetings led by the learned societies to implement this, it will be able to generate a significant synergy effect. This Article will concentrate on first examining the flow and patterns of the policy to train special manpower by the comics industry, the Ministry of Culture and related institutions since the establishment of the Comics Promotional Law, analyzing some problems in the first and second medium and long term development plan of the comics industry to be implemented from 2003 through 2013 and the third medium and long term development plan to be announced in June 2013 to train professional manpower, and then suggesting an effective direction and some alternatives to train professional manpower in universities in a medium and long term way.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.47-56
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• 2014

Recently, the velocity of sea-level rising has increased due to the global warming and the natural disasters have been occurred many times. Therefore, there are various demands for the integration of vertical reference datums for the ocean and land areas in order to develop a coastal area and prevent a natural disaster. Currently, the vertical datum for the ocean area refers to Local Mean Sea Level(LMSL) and the vertical datum for the land area is based on Incheon Mean Sea Level(IMSL). This study uses 31 points of Tidal Gauge Bench Mark (TGBM) in order to compares and analyzes the geometric heights referring LMSL, IMSL, and the nationally determined geoid surface. 11 points of comparable data are biased more than 10 cm when the geometric heights are compared. It seems to be caused by the inflow of river, the relocation of Tidal Gauge Station, and the topographic change by harbor construction. Also, this study analyze the inclination of sea surface which is the difference between IMSL and LMSL, and it shows the inclination of sea surface increases from the western to southern, and eastern seas. In this study, it is shown that TGBM can be used to integrate vertical datums for the ocean and land areas. In order to integrate the vertical datums, there need more surveying data connecting the ocean to the land area, also cooperation between Korea Hydrographic and Oceanographic Administration and National Geographic Information Institute. It is expected that the integrated vertical datum can be applied to the development of coastal area and the preventative of natural disaster.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.54-69
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• 2000

There are groundwater trouble by high-salinity yield inducing sea-water intrusion in Cheju Island. It is used groundwater-GIS(Well-lnfo) in the maintenance and management of groundwater in Cheju Island to grasp groundwater trouble area and cause of high-salinity yield. For 16 wells certain to yield high-salinity, we logged specific electrical conductivity(EC) and tried to get hold of freshwater and saltwater relationship. As result of distribution of $Cl^-$ by depth, it is showed up groundwater trouble by high-salinity yield in the east coastal area and the partly north coastal area. The reason of high-salinity groundwater yield are low-groundwater level by the structure of geology and low-hydraulic gradient etc. There is necessity for management to development and use of groundwater in the high-salinity area, special management area.

• Journal of agricultural medicine and community health
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• v.36 no.1
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• pp.1-12
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• 2011

Objectives: The purpose of this study was to find out the suicide ideation of high school students in urban and rural areas, and especially to research the relationship between suicide ideation, and general characteristics, characteristics of school life, and empirical characteristics of suicide. Methods: This research targeted four urban and four rural high schools in two cities. The study subjects were 1,114 students in urban area and 968 students in rural area, total 2,082 students. The survey was conducted from July 1, 2009 to July 31, 2009. For statistical analysis, chi-square test, t-test and ANOVA were used for investigating related factors with suicide ideation in urban and rural areas, respectively, with multiple logistic regression for multivariate analysis. Results: The results showed that 38.8% of respondents had suicide ideation within 1 year. The percentage of female students (44.8%) was significantly higher than that of male students (33.4%). However, there was no significant difference between urban (38.0%) and rural area (39.9%). The significant influencing factors on suicide ideation in multiple logistic regression were gender [female student OR(odds ratio)=1.80 (95% CI 1.31-2.47) compared with male student] and grade [second year OR=1.40 (95% CI 0.98-2.00), third year OR=2.15 (95% CI 1.49-3.12) compared with first year] in urban area. Those in rural area were gender [female student OR(odds ratio)=2.71 (95% CI 1.23-2.38) compared with male student], economic deterioration [yes OR=1.81 (95% CI 1.24-2.64) compared with no], and grade [second year OR=2.80 (95% CI 1.82-4.32), third year OR=3.84 (95% CI 2.52-5.87) compared with first year]. Conclusions: This study showed about 40% of high school students had suicide ideation within 1 year. A suicide prevention program may be implemented considering factors related with suicide ideation identified in this study.