• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.17 no.1
• /
• pp.10-18
• /
• 2006

Objective : The aims of this study were to explore the relations of internet addiction to depression, impulsivity, and obsessive-compulsivity in adolescents. Methods : 1410 high school students (male=611, female=799 : mean age=$16.2{\pm}0.7$) were included in this study. The questionnaire consisted of items on demographic characteristics and internet use pattern. We assessed the level of internet addiction using Young's internet addiction scale (IAS) Barratt impulsiveness scale (BIS) and Maudsley obsessive compulsive inventory (MOCI) were also self-rated. In this study, We defined upper 25% of IAS as 'addiction group' and lower 25% as 'non-addiction group'. Results : The results were as follows ; 1) Male students had significantly higher mean scores on Internet addiction scale than females and there was significantly higher rate of male students in addiction group. 2) The addiction group spent more time for internet use, especially for games than non-addiction group. 3) The addiction group showed significantly higher total scores on BDI, BIS, and MOCI than non-addiction group. 4) Significant associations have been found between the level of internet addiction and depression, impulsivity, and obsessive-compulsivity, respectively. Conclusion : Depression, impulsivity, and obsessive-compulsivity could be significant factors predicting internet addiction. Especially, direct effect of impulsivity could be the most significant to explain internet addiction. Adolescents with high impulsivity may be vulnerable to internet addiction.

• Economic and Environmental Geology
• /
• v.46 no.5
• /
• pp.425-444
• /
• 2013

This study was carried out in order to determine the remediation of total petroleum hydrocarbons (TPHs), trichloroethylene (TCE), perchloroethylene (PCE), benzene, toluene, ethylbenzene and xylenes (BTEX) compounds for non-aqueous phase liquids (NAPLs) using in-situ air sparging (IAS) / vapor extraction (VE) with the marine sediments of Mandol, Hajeon, Sangam and Busan, South Korea. Surface sediment of Mandol area had sand characteristics (average particle size, 1.789 ${\Phi}$), and sandy silt characteristics (average particle size, 5.503 ${\Phi}$), respectively. Sangam surface sediment had silt characteristics (average particle size, 5.835 ${\Phi}$). Sediment characteristics before experiment in the Busan area showed clay characteristics (average particle size, 8.528 ${\Phi}$). TPHs level in the B1 column of Mandol, Hajeon, Sangam, and Busan sediments were 2,459, 6,712, 4,348, and 14,279 ppm. B2 (3 L/min) to B5 (5 L/min) columns reduced 99.5% to 100.0% of TCE and 93.2% to 100.0% of PCE. Removal rates of TCE, PCE, and BTEX are closely correlated (0.90-0.99) with particle sizes and organic carbon concentrations. However, TPHs (0.76) and benzene (0.71) showed the poorer but moderate correlations with the same parameters.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.3933-3940
• /
• 2013

The purpose of present study was to determine the frequency of RA with age and to investigate the age-related trends and changing-factors in RA, CA and IAs. The refractive power of the eye and the power of corneal anterior surface were measured with auto-refractor among 1,017 inhabitants aged 5 to 59 years in Cheongju in July 2010. The overall frequency of RA was 22.7%, and frequency of RA increased from 8.9% in 5~9 years age group to 36.8% in 20~29 years age group. It then dipped to 19.2% in 40~49 years age group but increased again 28.6% in 50~59 years age group. $J_{45}$ components for RA, CA, and IAs were fairly stable in different age groups, the changes in $J_0$ components for both RA and CA appeared to be decreased after age of 30 years. In addition, the refractive power on the vertical direction was changed slightly with age, but the refractive power on the horizontal direction was changed significantly with age. It was expected that the change in the frequency of astigmatism with age was due to the change in the refractive power of horizontal meridian.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.6
• /
• pp.18-27
• /
• 2006

Air Sparging (IAS, AS) is a ground-water remediation technique, in which organic contaminants are volatilized into air as they rise from saturated to vadose soil zone. This study was conducted to investigate the variation characteristics of TPH, VOCs and $CO_2$ for air sparging of diesel contaminated saturated soil. Initial TPH concentration was 10,000 mg/kg for saturated soil phase and 1,001 mg/L for soil aquifer phase. After 36 days of air sparging, the equilibrium temperature of 2-Dimension experiment system was $24.9{\pm}1.5^{\circ}C$. The saturated soil TPH concentration (in the C10 port close to air diffuser) was reduced to 66.0% of the initial value. The mass amount of $CO_2$ was 3,800 mg and 3,200 mg in air space (C70 port) and in unsaturated soil zone (C50 port), respectively. The VOCs production kinetic parameter was 0.164/day in the air space (C70 port) and 0.182/day in the unsaturated soils (C50 port).

• Korean journal of applied entomology
• /
• v.17 no.1 s.34
• /
• pp.23-28
• /
• 1978

The study has been carried to confirm the pathotypes of Kresek inducing isolates of X. oryzae, and its reaction to the test plants when they were inoculated by the use of various methods. Induction of Kresek symptom by 23 isolates which randomly samplified from 123 Kresek areas through the country also were examined. The specificity of Pathotypes I, II, V in causing Kresek and the potenciality of infected rice straw is a first inoculum for Kresek epidemics in nature were tested. Fifteen out of 23 isolates from kresek area belonged to pathotype group I, while the rest of 8 isolates 5 howed group II reaction, and the most of isolates were originated from infected rice plant of Milyang #23. All of five pathotype groups were abled to produce 'Kresek' symptom although they showed some differences in each group of pathotype. The varieties Milyang #21, 22 and 23 were attacked by all isolates of group I, II and V while the Gogyoku group varieties including Yushin produced kresek symptom only by pathotype group II. Infected and dried straw maintained the pathogens during the winter period, and these straw acted as a first inoculum of Kresek disease when the straw were cutted and used as a manure just before transplanting of rice seedling.

• International Journal of Railway
• /
• v.1 no.4
• /
• pp.143-148
• /
• 2008

This paper is the output of a collaborative European project concerning the barrier free accessibility for disabled persons to regional and long distance trains in Europe. Disabled people represent around 13% of the population in Europe. This is approximately 63 million people. The range of disabilities includes people with reduced mobility including wheel chair users, viewing and hearing impaired people and other forms of impairment. Improving accessibility aims at contributing to the provision of public transport services to all citizens in an equitable way. The purpose of the project was to analyse and to evaluate the existing solutions at selected European railways for all required modules at the entrance (doors, information and safety solutions), to derive a design concept, to develop a mock-up in meeting the needs of rail travellers with the above mentioned impairments and to test it with user groups. The project also aims at deriving components for the determination of standards. The EUPAX Design Mock-up test was performed to verify the advantages of the layout of the train segment including the different modules such as access area (including the access door, gaps between platform and train as well as boarding aid devices), entrance vestibule, information systems inside and outside the train, emergency facilities, toilet with all conveniences and the additional test arrangements regarding push buttons, steps and emergency equipment. For this purpose a questionnaire was developed for the assessment of the EUPAX segment and the additional test arrangements. With the help of this questionnaire it was possible to execute a quantitative and qualitative evaluation. During three test phases 67 experts and handicapped persons from 6 countries have evaluated the Industrial Design mock-up based on this questionnaire. The test group covered persons from North (Denmark) to the South (Italy) and from the West (Spain) to the Middle of Europe (Germany). This is especially important for the generalization (harmonisation) of the results for all European countries. According to COST 335 the information for people with reduced mobility should be clear, concise, accurate and timely. So that all information can be received from persons, they must be transferred on at least two of the three possible ways (acoustical, visual, tactile), a so called "2-sense-principle". Based on the results ergonomic specifications/ solutions for the ergonomic design of the access area, the acoustic, visual and tactile information and the emergency devices including the emergency communication system were developed, related to the benefiting passenger groups.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.1
• /
• pp.10-18
• /
• 2022

With the increase in world trade through ships, the destruction of the marine ecosystem and socioeconomic damage due to invasive alien species (IAS) are continuously increasing. In particular, marine organisms attached on the hull surface and niche area increase the friction resistance of ships as well as the invasion of non-indigenous species, and causes a decrease in operational efficiency and an increase in GHG (Green House Gas) emissions. The International Maritime Organization (IMO) has recently begun revising guidelines for the control and management of ship's biofouling, and New Zealand and California in the United States are already regulating biofouling management under their own laws. This study investigated the management status of the submerged surface of ships and marine organisms attachments on five international ships entering South Korea, and analyzed species group and coverage (%) of biofouling communities to evaluate the LoF (Level of Fouling) rank. Macroflouling was observed on all ships surveyed, and specially, the adhesion of macro organisms in niche areas such as bow thruster, bilge keels and sea-chest gratings appeared to be at a serious level. This study proposed the management direction our country should take with regard to ship's biofouling and the improvement measures for evaluation of LoF rank and inspection methods of hull and niche ares.

• Korean Journal of Radiology
• /
• v.24 no.7
• /
• pp.681-689
• /
• 2023

Objective: Three-dimensional rotational angiography (3D-RA) is increasingly used for the evaluation of intracranial aneurysms (IAs); however, radiation exposure to the lens is a concern. We investigated the effect of head off-centering by adjusting table height on the lens dose during 3D-RA and its feasibility in patient examination. Materials and Methods: The effect of head off-centering during 3D-RA on the lens radiation dose at various table heights was investigated using a RANDO head phantom (Alderson Research Labs). We prospectively enrolled 20 patients (58.0 ± 9.4 years) with IAs who were scheduled to undergo bilateral 3D-RA. In all patients' 3D-RA, the lens dose-reduction protocol involving elevation of the examination table was applied to one internal carotid artery, and the conventional protocol was applied to the other. The lens dose was measured using photoluminescent glass dosimeters (GD-352M, AGC Techno Glass Co., LTD), and radiation dose metrics were compared between the two protocols. Image quality was quantitatively analyzed using source images for image noise, signal-to-noise ratio, and contrast-to-noise ratio. Additionally, three reviewers qualitatively assessed the image quality using a five-point Likert scale. Results: The phantom study showed that the lens dose was reduced by an average of 38% per 1 cm increase in table height. In the patient study, the dose-reduction protocol (elevating the table height by an average of 2.3 cm) led to an 83% reduction in the median dose from 4.65 mGy to 0.79 mGy (P < 0.001). There were no significant differences between dose-reduction and conventional protocols in the kerma area product (7.34 vs. 7.40 Gy·cm², P = 0.892), air kerma (75.7 vs. 75.1 mGy, P = 0.872), and image quality. Conclusion: The lens radiation dose was significantly affected by table height adjustment during 3D-RA. Intentional head off-centering by elevation of the table is a simple and effective way to reduce the lens dose in clinical practice.

• Journal of the Korean Home Economics Association
• /
• v.40 no.3
• /
• pp.67-82
• /
• 2002

The purpose of this study was to investigate the relation of social support and aggression of early adolescents. The subject were 220 adolescents aged 11 & 14 years, who were enrolled 11 child welfare facilities or 6 public schools(3 elementary & 3 middle schools) in Seoul. That is, 110 institutionalized(IA) & 110 middle class home-reared adolescent (HA)s were examined. They subjects were asked to complete the questionnaire on social support and aggression. According to the results, 1)IAs perceived less support from peers or adults and showed more aggressive behaviors than HAs. 2)Significant sex difference was observed in aggression. Girls showed lower level of aggression than boys. 3)Adolescents' aggression was significantly correlated with social support. The more support from friends, classmates, and parents HAs perceive, the less aggression they reported. Though support from peers was correlated significantly only with anger expression, support from parents was correlated significantly with all the components of aggression. And the more support from friends and classmates HAs perceive, the less aggression they reported. These findings implicate that social support is a important factor in preventing aggressive behaviors of early adolescents.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.9
• /
• pp.293-304
• /
• 2020

The study reveals the extent of changes in selective financial numbers caused by fixed asset revaluation (FAR) and explores whether there was a management motive for playing the financial numbers game through using the FAR model. The data set consists of a sample of 142 listed companies purposively selected from 13 industries. The study found a significant impact of FAR on the net asset value (NAV), fixed asset intensity (FAI), and debt-to-equity ratio (DER). These findings are supported by the political cost and the debt covenant hypotheses. The study also observed a high growth of fixed assets by 9.5% to 14,603.8% resulting from FAR. More revealing is that FAR increased NAV in revaluer companies by an average of 427.20% as compared to 6.86% in non-revaluer companies. Even some companies with negative NAV took resort on FAR to show positive NAV. Besides, revaluer companies managed to reduce their DER by 70.45% as opposed to an increase of 8.45% in non-revaluer companies. Hence, the study concludes that most of the publicly-listed companies are involved in financial numbers game by the use of the FAR model. To build confidence among investors, companies should practice FAR rightly and disclose related information to help reduce information asymmetry.