• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.16 no.2
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• pp.199-210
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• 2005

Objective : Attention deficit hyperactivity disorder(ADHD) affects $5-10\%$ of children in Korea, with more boys and girls being diagnosed. Despite seriousness of ADHD, little is known about its causes. From the current genetic epidemiologic studies, ADHD is known as a heritable disorder. Till now, however, there have been very few genetic studies about ADHD in Korea. The aim of the this study is to examine the association between dopamine transporter gone type 1 and ADHD using case-control design in Korean ADHD probands and normal controls. Materials and Method : Child Psychiatric Genetic research team in Seoul National University Hospital, Clinical Research Institute recruited the ADHD probands using clinical interview/observation, diverse rating scales, and neuropsychological tests. For eliminating phenocopy or ADHD, diagnosis of ADHD was based upon clinical data, psychometric data, and parent/teacher reports. Total 85 ADHD-probands were recruited as final study subjects and independent 100 normal adults participated in this study as control group. For all the ADHD probands, and controls, the 3'-UTR-VNTR polymorphism of DAT1 was analyzed. Based on the DAT1 allele and genotype informations, Chi-square test based on case-control design was performed. Results : As for genetic study, total of 85 probands and 100 controls were included for the genetic analysis. Four different alleles, 350bp (7repeat), 440bp (9repeat), 480bp (10repeat) and 520bp (11repeat) were found in DAT1 gene of study subjects. In case-control analysis, ADHD probands and parents have significantly more 9 repeat allele and 9/10 genotype. Also, The probands with 9repeat allele have more commission errors in ADS. Conclusion : The positive association between ADHD and DAT1 gene was replicated in this report like other previous results for caucasian children and Korean children with ADHD. There are ongoing studies on other candidate genes such as DRD4 and DRD5 and it would be required to explore the association of these candidate genes in Korean children with ADHD. These ongoing genetic research will contribute to the understanding of heterogenous genetic and environmental etiologies of ADHD phenotype, which will lead to the development of more comprehensive treatment and preventive interventions for ADHD.

• Journal of Preventive Medicine and Public Health
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• v.32 no.2
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• pp.177-182
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• 1999

Objectives: To reexamine the association between air pollution and daily mortality in Seoul, Korea using a method of meta-analysis with the data filed for 1991 through 1995. Methods: A separate Poisson regression analysis on each district within the metropolitan area of Seoul was conducted to regress daily death counts on levels of each ambient air pollutant, such as total suspended particulates (TSP), sulfur dioxide $(SO_2)$, and ozone $(O_3)$, controlling for variability in the weather condition. We calculated a weighted mean as a meta-analysis summary of the estimates and its standard error. Results: We found that the p value from each pollutant model to test the homogeneity assumption was small (p<0.01) because of the large disparity among district-specific estimates. Therefore, all results reported here were estimated from the random effect model. Using the weighted mean that we calculated, the mortality at a $100{\mu}g/m^3$ increment in a 3-day moving average of TSP levels was 1.034 (95% Cl 1.009-1.059). The mortality was estimated to increase 6% (95% Cl 3-10%) and 3% (95% Cl 0-6%) with each 50 ppb increase for 9-day moving average of SO2 and 1-hr maximum O3, respectively. Conclusions: Like most of air pollution epidemiologic studies, this meta-analysis cannot avoid fleeing from measurement misclassification since no personal measurement was taken. However, we can expect that a measurement bias be reduced in a district-specific estimate since a monitoring station is hefter representative cf air quality of the matched district. The similar results to those from the previous studios indicated existence of health effect of air pollution at current levels in many industrialized countries, including Korea.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.127-135
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• 2021

To respond to the threat of global warming, countries around the world are promoting the spread of renewable energy and reduction of carbon emissions. In accordance with the United Nation's Sustainable Development Goal to combat climate change and its impacts, global automakers are pushing for a full transition to electric vehicles within the next 10 years. Electric vehicles can be a useful means for reducing carbon emissions, but in order to reduce carbon generated in the stage of producing electricity for charging, a power generation system using eco-friendly renewable energy is required. In this study, we propose a smart electric mobility operating system integrated with off-grid solar power plants established in Tanzania, Africa. By applying smart monitoring and communication functions based on Arduino-based computing devices, information such as remaining battery capacity, battery status, location, speed, altitude, and road conditions of an electric vehicle or electric motorcycle is monitored. In addition, we present a scenario that communicates with the surrounding independent solar power plant infrastructure to predict the drivable distance and optimize the charging schedule and route to the destination. The feasibility of the proposed system was verified through test runs of electric motorcycles. In considering local environmental characteristics in Tanzania for the operation of the electric mobility system, factors such as eco-friendliness, economic feasibility, ease of operation, and compatibility should be weighed. The smart electric mobility operating system proposed in this study can be an important basis for implementing the SDGs' climate change response.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.87-95
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• 2002

The slow degradation rate of sludge in anaerobic digestion is due to rate-limiting step of sludge hydrolysis. To upgrading of sludge hydrolysis and biodegradabiliry, the pre-treatment had been carried out using acidlc (pH 1.5, 3, 4, 5) and alkaline (pH 9, 10, 13), thermal (50, 100, 150, $200^{\circ}C$), and ultrasonic treatment (400W, 20kHz, 15, 20, 25, 30, 40, 50, 60, 90min). In the best conditions of each treatment, the Soluble SCOD Ratio(%)of treated/untreated sample were increased 102% in acid (pH5), 986% in alkali (pH 13), 595% in thermal ($200^{\circ}C$) and 1123% in ultrasonic (35min) treatment. As the result, the ultrasonic treatment was most effective, followed by alkali, thermal, acid treatment. In the effects of total gas productivity in vial test, the thermal ($200^{\circ}C$) pre-treatment was the highest, followed by thermal ($150^{\circ}C$), ultrasonic (90min), alkaline (pH 9), and ultrasonic (50min). We compared untreated samples and the most efficient pre-treatment samples(at $200^{\circ}C$, for 30min) on gas productivity with changes of HRT in continuous experiments IN thermal treated samples were 2.5 times in SCOD, 2 times in soluble protein and 3.3 times high in soluble carbohydrate than untreated ones. In gas productivity, the thermal treated samples were average 2 times high than untreated ones. And HRT 7 days was most effective. followed by HRT 10, HRT 15 days. But The gas productiviry of HRT 2.5 days was less than untreated, the reason of low gas productivity was come from high organic acids accumulation within reactor.

• Journal of Oral Medicine and Pain
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• v.33 no.3
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• pp.257-267
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• 2008

The mentophysical disease causes diseases in digestive, respiratory, circulating systems, including chronic pain, through combined reactions from different individual characteristics, mental stress and temperamental factors. The most common symptom related to orofacial area is pain and the contributive factors include biological, behavioral, environmental, social, emotional, recognitive factors. These factors affect the course of the symptom according to individual's character and human nature. In pain, sleep acts as a contributive factor, and pain could bring about sleep disturbance and vice versa. Deterioration of sleep quality would act as a factor that aggravates mental stress. Therefore, relatively accurate and simple mental examinations and sleep quality test should be carried out for the patients with symptoms related to orofacial area. This study evaluated the mental state in relation to the sleep quality which could affect orofacial pain. The number of poor sleeper was 18 in male subjects, and 1 in female subjects and PSQI global index was higher in male($6.11{\pm}2.38$) than female($4.67{\pm}2.18$). SCL-90-R index showed no sex difference. Poor sleeper showed significantly high value in SOM, O-C, I-S, ANX, PHOB, PSY, GSI, PST. When SCL-90-R T scores were compared according to sleep quality, higher the subjective sleep quality score, O-C and I-S showed significant increase. As sleep disturbances score increased, PAR, PSY, PST showed statistically significant increase. In comparison of SCL-90-R T score according to daytime dysfunction, statistically significant increase in DEP, ANX, HOS, PHOB, PAR, GSI was observed. Therefore, the quality of sleep and psychological status have a high correlation. This is likely to influence chronic pain in the orofacial field. As a result, clinicians treating orofacial pain should evaluate the sleep quality and psychological status of the patient. Further studies of larger sample sizes including various age, occupation, and pain groups are necessary in order to apply the results to clinical practice.

• Korean Journal of Remote Sensing
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• v.31 no.5
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• pp.449-459
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• 2015

The conventional National Forest Inventory(NFI)-based forest carbon stock estimation method is suitable for national-scale estimation, but is not for regional-scale estimation due to the lack of NFI plots. In this study, for the purpose of regional-scale carbon stock estimation, we created grid-based forest carbon stock maps using spatial ancillary data and two types of up-scaling methods. Chungnam province was chosen to represent the study area and for which the $5^{th}$ NFI (2006~2009) data was collected. The first method (method 1) selects forest type map as ancillary data and uses regression model for forest carbon stock estimation, whereas the second method (method 2) uses satellite imagery and k-Nearest Neighbor(k-NN) algorithm. Additionally, in order to consider uncertainty effects, the final AGB carbon stock maps were generated by performing 200 iterative processes with Monte Carlo simulation. As a result, compared to the NFI-based estimation(21,136,911 tonC), the total carbon stock was over-estimated by method 1(22,948,151 tonC), but was under-estimated by method 2(19,750,315 tonC). In the paired T-test with 186 independent data, the average carbon stock estimation by the NFI-based method was statistically different from method2(p<0.01), but was not different from method1(p>0.01). In particular, by means of Monte Carlo simulation, it was found that the smoothing effect of k-NN algorithm and mis-registration error between NFI plots and satellite image can lead to large uncertainty in carbon stock estimation. Although method 1 was found suitable for carbon stock estimation of forest stands that feature heterogeneous trees in Korea, satellite-based method is still in demand to provide periodic estimates of un-investigated, large forest area. In these respects, future work will focus on spatial and temporal extent of study area and robust carbon stock estimation with various satellite images and estimation methods.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.283-288
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• 2011

This study was conducted to study the environment effects on live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score, which are the carcass traits of Hanwoo, based on the estimates and all the possible regression for the selection of variable and significance test for 231,382 heads that underwent the carcass measurements. The average and standard deviation for the live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score were 654.79${\pm}$91.61 kg, 362.30${\pm}$67.15 kg, 59.52${\pm}$0.03%, 81.79${\pm}$12.21 $cm^2$, 11.39${\pm}$5.40 mm, 4.38${\pm}$2.29, respectively. The live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score for cow were 532.79${\pm}$78.38 kg, 313.40${\pm}$44.90 kg, 56.50${\pm}$0.03%, 75.24${\pm}$10.69 $cm^2$, 11.82${\pm}$5.10 mm, 4.30${\pm}$2.06, respectively, while for bull were 619.74${\pm}$93.27 kg, 376.89${\pm}$48.62 kg, 58.61${\pm}$0.02%, 85.61${\pm}$10.46 $cm^2$, 5.64${\pm}$2.71 mm, 1.41${\pm}$0.83, respectively, and for steer were 681.78${\pm}$70.72 kg, 415.23${\pm}$49.43 kg, 60.19${\pm}$0.02%, 88.29${\pm}$10.27 $cm^2$, 12.71${\pm}$5.23 mm, 5.42${\pm}$1.99, respectively. In the environmental variables selection based on the variables selection method, the examination by carcass traits suggested that the most appropriate model could be determined when five variables were selected for the live weight, carcass weight, dressing percentage, eye muscle area, and four variables for backfat thickness, and marbling score. When they were considered at a time altogether based on multiple traits, it was deemed to be desirable to insert all five variables into the variables for analysis. In addition, high significance was found by carcass traits.

• Management & Information Systems Review
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• v.37 no.3
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• pp.1-25
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• 2018

This research performed the empirical test for the effects of learning transfer on perceived usefulness, perceived ease of use, self-efficacy and work environment using 390 employees who have experienced e-learning in domestic and foreign companies. Analyzed the mediating effects of self-efficacy and work environment in addition to direct effect of each factor on learning transfer. The results showed that perceived usefulness and perceived ease-of-use of e-learning learner had a positive(＋) effect on self-efficacy and a positive influence on supervisor and peer support and organizational climate. Self-efficacy showed a positive effect on learning transfer, and supervisor support, peer support and organizational climate had a positive influence on learning transfer as well. Perceived usefulness also had a positive effect on learning transfer. However, perceived ease-of-use had no significant effect on learning transfer. As a result of the mediating effect analysis, self-efficacy and work environment were analyzed to have mediating effects between perceived usefulness, perceived ease of use, and learning transfer. The implications of this study are as follows. First, this study designed a new research model that reflects factors influencing the effect of learning transfer on acceptance of e-learning that is common in corporate education. It has derived a research model of perceived usefulness and perceived ease-of-use, which were used as mediating variables for external characteristics factors, as independent variables, using self-efficacy and work environment as mediating variables, which were studied as external factors. Second, most of the studies on technology acceptance model and learning transfer are conducted in a single country. The reliability was enhanced by testing the study models using different samples from 26 countries. Third, perceived usefulness and ease-of-use in existing studies have been considered as key determinants of acceptance intention and learning transfer. This study explored the mediating effects of learner and environmental factors on the accepted information technology and strengthened and supplemented the path of learning transfer of perceived usefulness and ease-of-use. In addition, based on the sample analysis of various countries used in this study, it is expected that future international comparative studies will be possible.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.59-67
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• 1995

Blood lead assay by $D_2$ lamp background correction method of atomic absorption spectrophotometer(AAS) with wavelength of 283.3 nm is most popular in occupational health practice in Korea. On the other hand, $D_2$ lamp background correction method with wavelength of 217.0 nm is also often used in general chemical analysis for lead assay in general purpose. But both methods have some weakness of background correction which brought direct effect on the results of analysis. Recently blood lead assay with polarized Zeeman effect of AAS was introduced and is now preferred in many laboratory than $D_2$ correction method in blood lead analysis. But still AAS with $D_2$ lamp are widely used in the field of occupational health in Korea. This study compared blood lead assay data with $D_2$ correction methods(283.3 and 217.0 nm) and with that of polarized Zeeman effect correction method to evaluate the validity of 02 correction methods. The results obtained were as follows; 1. Taking the value of polarized Zeeman effect method as reference value of 1.00, the mean relative value of $D_2$ correction method with wavelength of 217.0 nm was 0.92 and that with wavelength of 283.3 nm was 0.90 respectively in the analysis of blood lead whose value were below $20.0{\mu}g/dl$(p<0.001). Both mean values were statistically smaller than polarized Zeeman effect correction method. But in the analysis of blood whose value were between 20.0 to $20.0{\mu}g/dl$, the mean relative value of $D_2$ correction method was 0.96 in both wavelength and did not differ from polarized Zeeman effect method(p<0.001). There was no difference of blood lead between $D_2$ correction method and polarized Zeeman effect method in the analysis of blood lead whose value were over $40.0{\mu}g/dl$. 2. The variations of background correction value in polarized Zeeman effect method were not changed by increase of blood lead, but those in $D_2$ correction methods were increased by the increase of blood lead. While then relative standard deviation(RSD) of data measured by Zeeman effect method were decreased by the increase of blood lead, those by $D_2$ methods were nol differed by the increase of blood lead.

• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.241-252
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• 2016

In this paper, in order to test the possibility of applying K feldspar $pIR-IRSL_{290}$ signal(read out at $290^{\circ}C$) to date old terrace sediments(up to ~ 200 ka, MIS 7) in Korea, we investigated luminescence properties of $pIR-IRSL_{290}$ signals in K feldspar extracts from 27 marine and fluvial terrace sediment samples, and these were compared with those of quartz OSL and conventional K feldspar $IRSL_{50}$ (readout at $50^{\circ}C$) signals. The averaged $2D_0$ value of K feldspar $pIR-IRSL_{290}$ growth curves was ~ 700 Gy, which is consistent with that of $IRSL_{50}$ signal, and this is 3 times higher than that for quartz OSL (~ 250 Gy) on average. Where possible, K feldspar $pIR-IRSL_{290}$ ages were compared with quartz OSL and conventional $IRSL_{50}$ ages. Our preliminary K feldspar $pIR-IRSL_{290}$ ages were older than quartz OSL ages by about 200%, while fading rate-corrected conventional $IRSL_{50}$ ages are in good agreement with those based on quartz OSL. This seems to indicate the possibility of K-feldspar $pIR-IRSL_{290}$ age overestimation due to the presence of unbleachable $pIR-IRSL_{290}$ signals, even with a prolonged exposure to sunlight. Both quartz OSL and K-feldspar $pIR-IRSL_{290}$ signals for the samples from Noeum fluvial terrace and Gusan fault site were all in dose saturation level, thus unable to estimate the formation ages of the sediments. However, $2D_0$ values derived from the dose response growth curves strongly indicate that the Noeum fluvial terrace sediments have formed before 109-140 ka, while the fluvial sediments from Gusan fault were desposited before 100-105 ka. Further, this seems to suggest that the previous quartz OSL ages of ~40-50 ka for Gusan fault sediments should be the underestimated ones due to dose saturation problem.