• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.5-13
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• 2014

Objectives: Depression, sleep complaints and cognitive impairments are commonly observed in the elderly. Elderly subjects with depressive symptoms have been found to show both poor cognitive performances and sleep disturbances. However, the relationship between sleep complaints and cognitive dysfunction in elderly depression is not clear. The aim of this study is to identify the association between sleep disturbances and cognitive decline in late-life depression. Methods: A total of 282 elderly people who underwent nocturnal polysomnography in a sleep laboratory were enrolled in the study. The Korean version of the Neuropsychological Assessment Battery developed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) was applied to evaluate cognitive function. Depressive symptoms were assessed with the geriatric depression scale (GDS) and subjective sleep quality was measured using the Pittsburg sleep quality index (PSQI). Results: The control group ($GDS{\leq}9$) when compared with mild ($10{\leq}GDS{\leq}16$) and severe ($17{\leq}GDS$) depression groups, had significantly different scores in the Trail making test part B (TMT-B), Benton visual retention test part A (BVRT-A), and Stroop color and word test (SCWT)(all tests p<0.05). The PSQI score, REM sleep duration, apnea-hypopnea index and oxygen desaturation index were significantly different across the three groups (all indices, p<0.05). A stepwise multiple regression model showed that educational level, age and GDS score were predictive for both TMT-B time (adjusted $R^2$=35.6%, p<0.001) and BVRT-A score (adjusted $R^2$=28.3%, p<0.001). SCWT score was predicted by educational level, age, apnea-hypopnea index (AHI) and GDS score (adjusted $R^2$=20.6%, p<0.001). Poor sleep quality and sleep structure alterations observed in depression did not have any significant effects on cognitive deterioration. Conclusion: Older adults with depressive symptoms showed mild sleep alterations and poor cognitive performances. However, we found no association between sleep disturbances (except sleep apnea) and cognitive difficulties in elderly subjects with depressive symptoms. It is possible that the impact of sleep disruptions on cognitive abilities was hindered by the confounding effect of age, education and depressive symptoms.

• Journal of Intelligence and Information Systems
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• v.16 no.4
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• pp.147-157
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• 2010

With the immergence of the iPhone, the interest in Smartphones is getting higher as services can be provided directly between service providers and consumers without the network operators. As the number of international tourists increase, individual tourists are also increasing. According to the WTO's (World Tourism Organization) prediction, the number of international tourists will be 1.56 billion in 2020,and the average growth rate will be 4.1% a year. Chinese tourists, in particular, are increasing rapidly and about 100 million will travel the world in 2020. In 2009, about 7.8 million foreign tourists visited Korea and the Ministry of Culture, Sports and Tourism is trying to attract 12 million foreign tourists in 2014. A research institute carried out a survey targeting foreign tourists and the survey results showed that they felt uncomfortable with communication (about 55.8%) and directional signs (about 21.4%) when they traveled in Korea. To solve this inconvenience for foreign tourists, multilingual servicesfor traffic signs, tour information, shopping information and so forth should be enhanced. The appearance of the Smartphone comes just in time to provide a new service to address these inconveniences. Smartphones are especially useful because every Smartphone has GPS (Global Positioning System) that can provide users' location to the system, making it possible to provide location-based services. For improvement of tourists' convenience, Seoul Metropolitan Government hasinitiated the u-tour service using Kiosks and Smartphones, and several Province Governments have started the u-tourpia project using RFID (Radio Frequency IDentification) and an exclusive device. Even though the u-tour or u-tourpia service used the Smartphone and RFID, the tourist should know the location of the Kiosks and have previous information. So, this service did not give the solution yet. In this paper, I developed a new convenient service which can provide location based information for the individual tourists using GPS, WiFi, and 3G. The service was tested at Insa-dong in Seoul, and the service can provide tour information around the tourist using a push service without user selection. This self-tour service is designed for providing a travel guide service for foreign travelers from the airport to their destination and information about tourist attractions. The system reduced information traffic by constraining receipt of information to tourist themes and locations within a 20m or 40m radius of the device. In this case, service providers can provide targeted, just-in-time services to special customers by sending desired information. For evaluating the implemented system, the contents of 40 gift shops and traditional restaurants in Insa-dong are stored in the CMS (Content Management System). The service program shows a map displaying the current location of the tourist and displays a circle which shows the range to get the tourist information. If there is information for the tourist within range, the information viewer is activated. If there is only a single resultto display, the information viewer pops up directly, and if there are several results, the viewer shows a list of the contents and the user can choose content manually. As aresult, the proposed system can provide location-based tourist information to tourists without previous knowledge of the area. Currently, the GPS has a margin of error (about 10~20m) and this leads the location and information errors. However, because our Government is planning to provide DGPS (Differential GPS) information by DMB (Digital Multimedia Broadcasting) this error will be reduced to within 1m.

• Korea and Global Affairs
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• v.2 no.1
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• pp.69-92
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• 2018

North Korea conducted a total of six nuclear tests from the 1st test of 2006 to September, 2017. North Korea developed an armed forces security strategy at the level of regime protection and defense to respond to U.S. hostile policy. However, it is certain that strategic goals of North Korea's nuclear test were to overcome a crisis in North Korea's regime through US-North Korea negotiation and complete nuclear armed forces for socialist unification on the Korean Peninsula. North Korea's continuous nuclear test is a direct factor in threatening peace on the Korean Peninsula and an indirect factor in security dynamics of Northeast Asia. The U.N. Security Council has enforced sanctions against North Korea through six resolutions against North Korea's reckless nuclear test for the past 10 years. However, Kim Jong-Un's regime is in a position to stick to simultaneous pursuit of nuclear and economic development in spite of anti-North sanction of international society including U.N. and U.S.A. It is understood that North Korea was stimulated to conduct intense nuclear test as U.N. and U.S.A's anti-North sanction was not effective on North Korea. Full-scale and local wars are expected as military options, one of anti-North sanctions of the Trump administration. The Trump administration has attempted diplomatic pressure strategy as a secondary boycott unlike previous administrations. Nevertheless, North Korea has stood against U.N. and U.S.A's anti-North sanction with brinkmanship tactics, announcing full-scale military confrontation against U.S. It is judged that North Korea will pursue simultaneous nuclear weapons and economic development in terms of regime survival. North Korea will have less strategic choices in that its regime may collapse because of realistic national strategy between U.S.A. and China.

• Progress in Medical Physics
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• v.23 no.2
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• pp.81-90
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• 2012

The effect of setup uncertainties on CTV dose and the correlation between setup uncertainties and setup margin were evaluated by Monte Carlo based numerical simulation. Patient specific information of IMRT treatment plan for rectal cancer designed on the VARIAN Eclipse planning system was utilized for the Monte Carlo simulation program including the planned dose distribution and tumor volume information of a rectal cancer patient. The simulation program was developed for the purpose of the study on Linux environment using open source packages, GNU C++ and ROOT data analysis framework. All misalignments of patient setup were assumed to follow the central limit theorem. Thus systematic and random errors were generated according to the gaussian statistics with a given standard deviation as simulation input parameter. After the setup error simulations, the change of dose in CTV volume was analyzed with the simulation result. In order to verify the conventional margin recipe, the correlation between setup error and setup margin was compared with the margin formula developed on three dimensional conformal radiation therapy. The simulation was performed total 2,000 times for each simulation input of systematic and random errors independently. The size of standard deviation for generating patient setup errors was changed from 1 mm to 10 mm with 1 mm step. In case for the systematic error the minimum dose on CTV $D_{min}^{stat{\cdot}}$ was decreased from 100.4 to 72.50% and the mean dose $\bar{D}_{syst{\cdot}}$ was decreased from 100.45% to 97.88%. However the standard deviation of dose distribution in CTV volume was increased from 0.02% to 3.33%. The effect of random error gave the same result of a reduction of mean and minimum dose to CTV volume. It was found that the minimum dose on CTV volume $D_{min}^{rand{\cdot}}$ was reduced from 100.45% to 94.80% and the mean dose to CTV $\bar{D}_{rand{\cdot}}$ was decreased from 100.46% to 97.87%. Like systematic error, the standard deviation of CTV dose ${\Delta}D_{rand}$ was increased from 0.01% to 0.63%. After calculating a size of margin for each systematic and random error the "population ratio" was introduced and applied to verify margin recipe. It was found that the conventional margin formula satisfy margin object on IMRT treatment for rectal cancer. It is considered that the developed Monte-carlo based simulation program might be useful to study for patient setup error and dose coverage in CTV volume due to variations of margin size and setup error.

• Progress in Medical Physics
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• v.24 no.4
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• pp.315-322
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• 2013

The aim of this work is to verify the self-quality assurances in medical institutions in Korea through the external audits by the group of experts and have a mutual discussion of the systematic problems. In order to validate the external audits 30 of 80 medical institutions across the nation were picked out considering the regional distribution and the final 25 institutions applied voluntarily to take part in this work. The basic rules were setup that any information of the participants be kept secrete and the measurements be performed with the dosimetry system already verified through intercomparision. The outputs for 2 or more photon beams, the accuracy of gantry rotation and collimator rotation and the poistional accuracy of MLC movement were measured. The findings for the output measurement showed the differences of -0.8%~4.5%, -0.79%~3.01%, and -0.7%~0.07% with respect to that of the verified dosimetry system for the 6MV, 10MV, and 15MV, respectively. For the reference absorbed dose 8 (16%) of 50 photon beams in 25 medical institutions differed 2.0% or greater from the reference value. The coincidences of Field size with x-ray beam and radiation isocenters of Gantry roration and collimator rotation gave the results of within ${\pm}2$ mm for every institute except 2 institutions. The positional accuracy of MLC movement agreed to within ${\pm}1$ mm for every institute. For the beam qualities of 6 MV photon beams kQ values showed the distribution within 0.4% between maximum and minimum. For the protocols 21 institutions (84%) used absorbed dose to water based protocol while 4 insitutions (16%) used air kerma based one. 22 institutions employed the SSD technique while 3 institutions did the SAD one. External audit plays an important role in discovering the systematic problems of self-performing Quality Assurances and having in depth discussion for mutual complementation. Training experts of international level as well as national support system are required so that both the group of experts of medical physicists and government laboratory could perform together periodical and constant external audits.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.383-392
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• 2007

Karstic features and mining-related cavities not only lead to severe restrictions in land utilizations, but also constitute serious concern about geohazard and groundwater contamination. A microgravity survey was applied for detecting, mapping and monitoring karstic cavities in the test site at Muan prepared by KIGAM. The gravity data were collected using an AutoGrav CG-3 gravimeter at about 800 stations by 5 m interval along paddy paths. The density distribution beneath the profiles was drawn by two dimensional inversion based on the minimum support stabilizing functional, which generated better focused images of density discontinuities. We also imaged three dimensional density distribution by growing body inversion with solution from Euler deconvolution as a priori information. The density image showed that the cavities were dissolved, enlarged and connected into a cavity network system, which was supported by drill hole logs. A time-lapse microgravity was executed on the road in the test site for monitoring the change of the subsurface density distribution before and after grouting. The data were adjusted for reducing the effects due to the different condition of each survey, and inverted to density distributions. They show the change of density structure during the lapsed time, which implies the effects of grouting. This case history at the Muan test site showed that the microgravity with accuracy and precision of ${\mu}Gal$ is an effective and practical tool for detecting, mapping and monitoring the subsurface cavities.

• Journal of Plant Biology
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• v.28 no.2
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• pp.105-118
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• 1985

This study was carried out to investigate the epidermal structure and types of stomata on the upper and lower surfaces of the leaves in six species and one variety belonging to Korean Crassulaceae. The shape of epidermal cells was polygonal, isodiametric, or elongated. The cell wall was thick, sinuous or deeply sinuous. The subsidiary cell wall was thin or mostly arched. The cytolith-containing cells were found in Orostachys japonicus. The distribution of stomata was more on the upper surface than on the lower surface in the leaves of O. japonicus and Sedum sarmentosum. The stomata in the other species were less on the upper surface than on the lower surface, and stomatal size was different in each species. The great majority of stomatal types was the helico-eumesogenous type. This type was subdivided into two, parahelico-eumesogenous type and diahelico-eumesogenous type by us on the basis of the angle of division of guard mother cell and the long axis of the last-formed subsidiary cells. Sometimes allelo-eumesogenous type as well as aniso-eumesogenous type was found. The tetra-eumesogenous type with four mesogenous subsidiary cells was rarely observed. It was observed that the varieties of aniso-eumesogenous type with one to three subsidiary cells and one helix of subsidiary cells were developed by the secondary division of subsidiary cells of aniso-eumesogenous stoma. The compound shape of helico-eumesogenous stomata was found. Five new kinds of stomatal types were observed as follows; the helico-tetra-eumesogenous type, the coallelohelico-eumesogenous type, the cohelico-allelo-eumesogenous type, the duplotetra-eumesogenous type, and the aniso-euperigenous type. These types were reported here in the vascular plants for the first time.

• Journal of agricultural medicine and community health
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• v.30 no.1
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• pp.51-62
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• 2005

Objectives: This study was conducted to understand the recognition on brucellosis in rural communities and to apply the results to counterplan for brucellosis control and prevention. Methods: The authors conducted a questionnaire survey from September 8 to 13, 2004 among the residents in 2 rural communities: 507 people at Gigye-myeon and 521 people at Buk-myeon. The authors developed a questionnaire which investigated age, gender, general recognition of brucellosis, status of cattle breeding, compensation for loss due to brucellosis and so on. Results: The study group contained 195 (19.0%) stock breeders (veterinarians and cattle merchants were included) and 833 (81.0%) non-stock breeders. For the question, 'Have you ever heard about brucellosis or do you know about brucellosis?', 283 respondents (27.5%) replied affirmatively. For the question, 'Do you know that pregnant women who suffer brucellosis may have a miscarriage?', 98 respondents (35.1%) replied affirmatively. For the question, 'Have your cattle ever aborted or calved a premature calf?', 28 respondents (14.9%) replied affirmatively. For the question, 'Have you ever handled an abortus or a premature calf with your bare hands?', 10 respondents (5.3%) replied affirmatively. For the question, 'Do you know that the government compensates for slaughter loss due to brucellosis?', 46 respondents (25.0%) replied affirmatively. Conclusions: Many people were ignorant about brucellosis. Therefore, their ignorance must be corrected by a publicity campaign. Some stock breeders handled the cattle abortus with their bare hand. Stock breeders must wear protective equipment during working. The authors expect that this study will assist in establishing both a safe cattle breeding environment and preventive strategies for diminishing the incidence of brucellosis.

• Journal of agricultural medicine and community health
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• v.25 no.1
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• pp.113-131
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• 2000

Transtheoretical model of change has been proven very effective in explaining both the acquisition and cessation of many health related behaviors. The objectives of this study were to describe the distribution of smokers by stage of change of smoking, alcoholic drinking, and exercising in rural residents and to develope health promotion strategies. This study was done in Okchun County of Chungbuk Province. The representative sample were 892 residents over 30 years old. The questionnaires of interview included socio-demographic, the six stage distribution of smoking, alcoholic drinking, and exercising. In male, 50.6% of smokers were in the precontemplation stage, 32.5% in the contemplation. In female, corresponding figures were 60.6% and 28.8%. Precontemplation and contemplation stage of drinker were 72.8%, 19.3% in male and 80.3%, 15.5%. Distribution of exercise were 80.6%, 1.8% in male, 87.6%, 1.2% in female, respectively. The stage distribution of smoker, alcoholic drinker, and exerciser was shift to left of the distribution. And the stage distribution was slightly differ with each health behavior. The stage of change with smoking, drinking and exercising was correlated with each other but not concordant. So interventions in rural residents need to take into account the large proportion of precontemplators repeatedly observed among smoker, drinker, and non-exerciser. And intervention strategies of each risk behavior should be different approach. Result of concordance analysis suggest reconstruct validity of the transtheoretical model in our country due to ethnic and sociocultural difference. This results and theory should be tested in prospective intervention studies for seeking the possible gateway of health behavior.

• Journal of agricultural medicine and community health
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• v.28 no.1
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• pp.39-51
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• 2003

Objectives: The oriental medical care has been getting popular in community health centers because of uniqueness, changing of disease patterns, and increasing of elderly population. From 1998, oriental medical doctors has been working in several rural community health centers for their military obligations. At this point of time, it is necessary to evaluate the oriental public health doctors system. This study was performed to investigate the utilization patterns, the degree of satisfactions, needs of oriental medical care service provided by community health center in a designated Gun area. This study focused on the need for extending over Myun area of community health center's oriental medical care services. Methods: Person-to-person interview survey method through a structured questionnaire was done by a personnel at a oriental medical care service room in a Gun community health center. The major statistical method used for the analysis were the t-test, ANOVA, and logistic analysis. Results: The total number of responded subjects in this study was 163 residents. Among these 65.0% were aged 61 or over, and only 13.5% recognized themselves were healthy. 73.7% of the respondents demanded establishment of more oriental medical care services provided by community health center to other Myun area. Factors affecting the need for enlargement of oriental medical care service room were education level, subjective awareness of access to community health center, and cost satisfaction of oriental medical service provided by community health center. Thus, a resident who had graduation of middle school achievement or above(OR=3.35), had a long way to center(OR=2.47), satisfied with oriental medical service cost(OR=2.78) had demonstrated increased chance of need by logistic regression analysis.