• Journal of the Institute of Convergence Signal Processing
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• v.14 no.3
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• pp.147-153
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• 2013

Functional game, which is the combination of play and learning and a futuristic tool, can minimize the dysfunction and maximize the proper functions, and furthermore, has taken root as a new alternative that can change the game industry and game culture. Recently, the focus of game and education markets is shifting to the development of more advanced learning contents, rather than emphasizing the self-control and motivation of users. Along with that, the game market has excluded the socially dysfunctional elements, such as the addiction and learning disabilities, and has witnessed a diversification into the human-friendly entertainment business that emphasizes the mental and physical health and pursues scientific educational effects. In addition, functional games are expanding its reach from the professional sectors - such as medical aide/medical learning, military simulation, health, auxiliary tools, special education and learning tools - to the realm of routine education, mental health, etc., and has seen a steady growth. However, most functional games, which are being currently planned and developed to cope with the special characteristics of the market, have not undergone accurate scientific assessment of their functions and have not proven their effectiveness. An overwhelming proportion of the functional games are being developed based on the intuition and experience of game developers. Moreover, the type of games, which involve the repetition of simple tasks or take the form of simple puzzles, cannot effectively combine the practically interesting factors and the learning effects. Most games incorporate unscientific methods leading to the vague anticipation of improvement in functions, rather than the assessment of human functions. In this paper, a study was conducted to present the measures that could maximize the effects of functional games in relation to the changes in the visual and auditory stimulations in order to maximize the effects of functional games, i,e., the immersion and concentration. To compare the degree of effects arising from the visual stimulation, the functional game contents made in the form of 2D and 3D were utilized. In addition. ultra sound and 3-dimensional functional game contents were utilized to compare the degree of effects resulting from the changes in the auditory stimulation. The brainwave of the users were measured while conducting the experiments related to the response to the changes in visual and auditory stimulations in 3 steps, and the results of the analysis were compared.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.2
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• pp.94-101
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• 2015

To mitigate the greenhouse gas emission, many carbon capture and storage projects are underway all over the world. In Korea, many studies focus on the storage of $CO_2$ in the offshore sediment. Assurance of safety is one of the most important issues in the geological storage of $CO_2$. Especially, the assessment of possibility of leakage and amount of leaked $CO_2$ is very crucial to analyze the safety of marine geological storage of $CO_2$. In this study, the leakage of injected $CO_2$ through fault was numerically studied. TOUGH2-MP ECO2N was used to simulate the subsurface behavior of injected $CO_2$. The storage site was 150 m thick saline aquifer located 825 m under the continental shelf. It was assumed that $CO_2$ leak was happened through the fault located 1,000 m away from the injection well. The injected $CO_2$ could migrate through the aquifer by both pressure difference driven by injection and buoyancy force. The enough pressure differences made it possible the $CO_2$ to migrate to the bottom of the fault. The $CO_2$ could be leaked to seabed through the fault due to the buoyancy force. Prior to leakage of the injected $CO_2$, the formation water leaked to seabed. When $CO_2$ reached the seabed, leakage of formation water stopped but the same amount of sea water starts to flow into the underground as the amount of leaked $CO_2$. To analyze the effect of injection rate on the leakage behavior, the injection rate of $CO_2$ was varied as 0.5, 0.75, and $1MtCO_2/year$. The starting times of leakage at 1, 0.75 and $0.5MtCO_2/year$ injection rates are 11.3, 15.6 and 23.2 years after the injection, respectively. The leakage of $CO_2$ to the seabed continued for a period time after the end of $CO_2$ injection. The ratios of total leaked $CO_2$ to total injected $CO_2$ at 1, 0.75 and $0.5MtCO_2/year$ injection rates are 19.5%, 11.5% and 2.8%, respectively.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.253-261
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• 2002

A spatially adaptive falter was formulated to imrove PET image qualify and the Performance of the filter was evaluated using simulation and phantom and human PET studies. In the proposed filter. if a pixel was identified as the edge Pixel, the Pixel value was Preserved. Otherwise a Pixel was replaced by the mean of the pixel values weighted by 2:7: 2. A Pixel was identified as the edge Pixel. if it satisfies the following conditions : the number of ADs (absolute difference between center and neighborhood pixels) which is smaller than THl (($pix_max{\times}0.1/log_2(NPM)$, NPM : mean of 6 neighborhood pixels excluding minimum and maximum) is 8-k and the number of ADs which is lager than TH2 ($NPM{\times}0.1$) is k. where k : 2, 3, …, 6. The results of this study demonstrate the superior performance of the Proposed titter compared to Gaussian fitter, weight median filter and subset averaged median filter. The proposed tittering method is simple but effective in increasing uniformity and contrast with minimal degradation of spatial resolution of PET images and thus. is expected to Provide improved diagnositc quality PET images .

• Journal of the Society of Disaster Information
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• v.9 no.4
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• pp.449-461
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• 2013

As the hydrofluoric acid leak in Gumi-si, Gyeongsangbuk-do or hydrochloric acid leak in Ulsan, Gyeongsangnam-do demonstrated, chemical related accidents are mostly caused by large amounts of volatile toxic substances leaking due to the damages of storage tank or pipe lines of transporter. Safety assessment is the most important concern because such toxic material accidents cause human and material damages to the environment and atmosphere of the surrounding area. Therefore, in this study, a hydrofluoric acid leaked from a storage tank was selected as the study example to simulate the leaked substance diffusing into the atmosphere and result analysis was performed through the numerical Analysis and diffusion simulation of ALOHA(Areal Location of Hazardous Atmospheres). the results of a qualitative evaluation of HAZOP (Hazard Operability)was looked at to find that the flange leak, operation delay due to leakage of the valve and the hose, and toxic gas leak were danger factors. Possibility of fire from temperature, pressure and corrosion, nitrogen supply overpressure and toxic leak from internal corrosion of tank or pipe joints were also found to be high. ALOHA resulting effects were a little different depending on the input data of Dense Gas Model, however, the wind direction and speed, rather than atmospheric stability, played bigger role. Higher wind speed affected the diffusion of contaminant. In term of the diffusion concentration, both liquid and gas leaks resulted in almost the same $LC_{50}$ and ALOHA AEGL-3(Acute Exposure Guidline Level) values. Each scenarios showed almost identical results in ALOHA model. Therefore, a buffer distance of toxic gas can be determined by comparing the numerical analysis and the diffusion concentration to the IDLH(Immediately Dangerous to Life and Health). Such study will help perform the risk assessment of toxic leak more efficiently and be utilized in establishing community emergency response system properly.

• Journal of Nutrition and Health
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• v.43 no.4
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• pp.404-412
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• 2010

This paper specifically discusses the risk assessment on the pesticide residues in vegetables collected from traditional markets, big marts and departments in the southern part of Seoul. Vegetable samples were 6,583 cases from January to December in 2009. Monte-Carlo simulation was used to calculate the uncertainty for the risk index using pesticide residues, average dietary intake for vegetables and acceptable daily intake. Deterministic risk indexes were 7.33% of diethofencarb, 5.13% of indoxacarb, 3.96% of EPN, 3.92% of diniconazole and 3.09% of chlorothalonil, respectively. And other pesticides were below 3%. Distributions of risk indexes obtained by the Monte-Carlo simulations were similar to the deterministic values, even though the confidence intervals for 95% were very wide. We confirmed that health risks caused by eating vegetables exceeded maximum residue limits of pesticide are very low and the population is generally safe, judging from the risk indexes located between 0.07 to 9.49%.

• Journal of Nutrition and Health
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• v.41 no.6
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• pp.561-572
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• 2008

Currently, Korea is facing dramatic nutrition transition among children, which may increase risk of degenerative diseases due to excessive intakes of fats, sugars and sodium. Promotion of eating healthier foods among children is difficult because the present nutrition label is not easily understood. Therefore, to promote healthier foods this study was aimed at developing guidance of standard amounts of high, medium and low levels of sugars, sodium, fats and other components contained in foods or drinks that are promoted to or formulated for consumption by children. Multipronged approach was used to collecting information, including key word searches in Medline and other databases, internet searches, reports from world organization, and contact of key individuals who work in organizations. We reviewed dietary reference intakes for Koreans, nutrient reference values, nutrient content claims of nutrition labeling, guideline daily amounts of United Kingdom, dietary guidelines and consumption data of nutrients, and selected components for labeling. And we decided goals of guideline daily amounts for children and nutrient criteria to underpin the high, medium and low content of each component. Then we collected data on processed foods sold at 12 middle schools and 11 high schools in Seoul, and classified processed foods into food category. Sales per one student per day were in the order of snacks, breads, and non-carbonated drinks. One hundred forty five mostly consumed products were selected and classified into criteria of high, medium and low total fat or sodium. Eighty five(58.6%) were classified into high fat food and only 11(7.6%) into high sodium food, in case that the base is chosen per 100 g or 100 mL. In conclusion, the nutrient criteria and choice of 100 g base, which we suggest in this study, need to be tested by simulation with more processed foods and refined in view of the practical issues suggested by stakeholders in future.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.63-72
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• 2012

Current analysis method drives an irrationality a road, signal operation and cause confusion of road such as weaving, bottleneck being not including main traffic flow in analysis subject. Therefore, this research develops analysis method of simple grade facilities to grasp target equipment relationship effect as virtue process to grasp effect of simple grade facilities in city and there is the purpose to apply optimum space of analysis intersection. In this paper, get at effect of simple grade facilities in urban area, as well as, develop new analysis method of simple grade facilities and adapt optimal interval of intersection point. New method of this paper reasonably estimated to optimal interval of the traffic flow(diverge area, merge area). As research result, analysis method to present in this research could clarify vague part of existing analysis method and presume reasonable result. Optimal interval of diverge and merge area with facilities was appeared more then 65m from the main line and more then 45m from the frontage road. Meaning of this paper as follow. First, the effect of simple grade facilities estimate. as consider optimal interval of simple grade facilities in urban can plan efficiently operation planning of road and signal in connection with nearby intersection. Second, new method then previous methods. planner of transportation easily access due to run parallel with existing method. Third, new method is contained through traffic volumes. the existing method did not reflect one. and this new method reduce error to the minimum. when analysis of intersection and link. Fourth, using the new method propose improvement plan with road operation and signal operation.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.337-347
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• 2015

Since the application of roundabouts by 2010 have been started, more than 350 roundabouts were installed in Korea. Recently the types of constructed roundabouts become various, and the intersection conditions for installing roundabouts were also various. However, there were some difficulties to install roundabouts around school zone due to safety problems. In this study, appropriate distance from adjacent signal crosswalks to roundabouts were estimated for securing pedestrian safety and operation efficiency around school zone. With the analyses, the minimum distance standard was suggested to obtain operational effectiveness of roundabout according to traffic volume, traffic flow, pedestrian green time and secures pedestrian safety and convenience. In this paper, average delay of roundabout as various length of distances between an adjacent crosswalk and a roundabout as different pedestrian signal times, traffic volumes, traffic flow rates were analyzed. Through this study, it was found that about four times of delay in a roundabout was generated if there was adjacent signal crosswalk. However if there is enough distance between an adjacent crosswalk and a roundabout, the value of increasing delay on roundabouts with adjacent a signalized crosswalk can be considerably reduced. Critical value of the distance between a roundabout and a signal crosswalk in case of roundabouts within 200-500 vehicle/hour/lane entry traffic flow, 20-40% of left turn traffic, and over 15 seconds pedestrian green time was about 50 meters. In conclusion, if there is minimum 40 meter distance from roundabouts, adjacent signal crosswalks can be installed and operated for students' safety around school zone.

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.9-17
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• 2017

A high degree of precision and accuracy in Gamma Knife Radiosurgery(GKRS) is a fundamental requirement for therapeutical success. Elaborate radiation delivery and dose gradients with the steep fall-off of radiation are clinically applied thus necessitating a dedicated Quality Assurance(QA) program in order to guarantee dosimetric and geometric accuracy and reduce all the risk factors that can occur in GKRS. In this study, as a part of QA we verified the accuracy of single-shot dose profiles used in the algorithm of Gamma Knife Perfexion(PFX) treatment planning system employing Variable Ellipsoid Modeling Technique(VEMT). We evaluated the dose distributions of single-shots in a spherical ABC phantom with diameter 160 mm on Gamma Knife PFX. The single-shots were directed to the center of ABC phantom. Collimating configurations of 4, 8, and 16 mm sizes along x, y, and z axes were studied. Gamma Knife PFX treatment planning system being used in GKRS is called Leksell GammaPlan(LGP) ver 10.1.1. From the verification like this, the accuracy of GKRS will be doubled. Then the clinical application must be finally performed based on precision and accuracy of GKRS. Specifically the width at the 50% isodose level, that is, Full-Width-of-Half-Maximum(FWHM) was verified under such conditions that a patient's head is simulated as a sphere with diameter 160mm. All the data about dose profiles along x, y, and z axes predicted through VEMT were excellently consistent with dose profiles from LGP within specifications(${\leq}1mm$ at 50% isodose level) except for a little difference of FWHM and PENUMBRA(isodose level: 20%~80%) along z axis for 4 mm and 8mm collimating configurations. The maximum discrepancy of FWHM was less than 2.3% at all collimating configurations. The maximum discrepancy of PENUMBRA was given for the 8 mm collimator along z axis. The difference of FWHM and PENUMBRA in the dose distributions obtained with VEMT and LGP is too small to give the clinical significance in GKRS. The results of this study are considered as a reference for medical physicists involved in GKRS in the whole world. Therefore we can work to confirm the validity of dose distributions for all collimating configurations determined through the regular preventative maintenance program using the independent verification method VEMT for the results of LGP and clinically assure the perfect treatment for patients of GKRS. Thus the use of VEMT is expected that it will be a part of QA that can verify and operate the system safely.

• Journal of Korean Society of Rural Planning
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• v.24 no.3
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• pp.73-86
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• 2018

Agricultural or rural landscape provides various ecosystem services. However, the ecosystem services function is declining due to various environmental problems such as climate change, land use change, stream intensification, non-point pollution and garbage. The A1B scenario predicts that the mean air temperature of South Korea will rise $3.8^{\circ}C$ degrees celsius in 2100. Agricultural sector is very vulnerable to climate change, so it must be thoroughly predicted and managed. In Korea, the facility horticulture complex is 54,051ha in 2016 and is the 3rd largest in the world(MAFRA, 2014). Facilities of horticultural complexes are reported to cause problems such as groundwater decrease, vegetation and insects diversity reduction, landscapes damage and garbage increase, compared with the existing land use paddy fields. Heat island phenomenon associated with climate change is also accelerated by the high heat absorption of horticultural sites. Therefore, we analyzed the heat island phenomenon occurring in the facility of horticultural complex in Korea. As an improvement measurement, I examined how much air temperature is reduced by putting the channel and the open space. In the case of the Buyeo area, the Computational Fluid Dynamics (CFD) simulation was analyzed for the average summer temperature distribution in the current land use mode at $38.9^{\circ}C$. As an improvement measurement, CFD simulation after 10% of 6m water channel was found to have an effect of lowering the summer temperature of about $2.7^{\circ}C$ compared with the present average of $36.2^{\circ}C$. In addition, CFD simulations after analyzing 10% of the open space were analyzed at $34.7^{\circ}C$, which is $4.2^{\circ}C$ lower than the present. For the Jinju area, CFD simulations were analyzed for the average temperature of summer at $37.8^{\circ}C$ in the present land use pattern. As an improvement measure, CFD simulations after 10% of 6m water channel were found to have an effect of lowering the summer temperature of about $2.6^{\circ}C$ compared to the current average of $35.2^{\circ}C$. In addition, CFD simulations after analyzing 10% of the open space were analyzed at $33.9^{\circ}C$, which is $3.9^{\circ}C$ lower than the present. It can be said that the effect of summer temperature drop in open space and waterway has been proven. The results of this study are expected to be reflected in sustainable agriculture land use and used as basic data for government - level policy in land use planning for climate change.