• Atmosphere
• /
• v.18 no.1
• /
• pp.25-32
• /
• 2008

Log normalized volume size distribution (dV/dlog$D_p$) with 52 size ranges from 0.5 to $20.0{\mu}m$ was measured for the cases of high $PM_{10}$ mass concentration (> $200{\mu}gm^{-3}$) using the Aerodynamic Particle Sizer (APS) at the Korea Global Atmosphere Watch Center (KGAWC) from 6 April, 2006 to 5 April, 2007. Black Carbon (BC), gaseous pollutants of $NO_X$ and $SO_2$ and ${\AA}ngstr\ddot{o}m$ exponent were also measured to examine the properties of the volume size distribution. From distinct difference of the high volume concentration (> $100{\mu}m^3cm^{-3}$), the volume size distribution for each event day was clasified into four types: (1) Type 1 had the high volume concentration for supermicron particles from 2.3 to $6.0{\mu}m$ and maximum average volume concentration was $160.7{\mu}m^3cm^{-3}$ at $3.5{\mu}m$. (2) Type 2 represented the high volume concentration in the both size range of submicron ($0.7-1.0{\mu}m$) and supermicron particles ($2.1-4.1{\mu}m^3cm^{-3}$ and $136.2{\mu}m^3cm^{-3}$ were found at 0.8 and $3.3{\mu}m$ respectively. (3) Type 3 showed the high volume concentration in the size range of $0.5-3.5{\mu}m$ and highest volume concentration of $201.1{\mu}m^3cm^{-3}$ at the particle size bin of $0.8{\mu}m$. (4) Type 4 was characterized by the high volume concentration for the fine particles less than $1.2{\mu}m$ and very high concentration of $446.8{\mu}m^3cm^{-3}$. ${\AA}ngstr\ddot{o}m$ exponent, concentration of gaseous ($NO_X$ and $SO_2$), and particle (BC) pollutants suggested that Type 1 was a typical volume size distribution for the Asian dust and Type 3 provided transportation of air pollutants. The distribution in Type 2 found to have both characteristics of the Asian dust and air pollutants, and Type 4 was took place during the foggy atmosphere containing high density of local pollutants. Based on the properties of volume size distribution, we can identify the three major events contributing the increase of $PM_{10}$ mass concentration, and hope to provide a guideline for discriminating the Asian dust from high $PM_{10}$ events. More case studies and longeto advance this determination method.

• Water for future
• /
• v.25 no.1
• /
• pp.93-100
• /
• 1992

A study on the Derivation of the Unit Hydrograph using Multiple Regression Moe이. The purpose of this study is to deriver an optimal unit hydrograph suing the multiple regression model, particularly when only small amount of data is available. The presence of multicollinearity among the input data can cause serious oscillations in the derivation of the unit hydrograph. In this case, the oscillations in the unit hydrograph ordinate are eliminated by combining the data. The data used in this study are based upon the collection and arrangement of rainfall-runoff data(1977-1989) at the Soyang-river Dam site. When the matrix X is the rainfall series, the condition number and the reciprocal of the minimum eigenvalue of XTX are calculated by the Jacobi an method, and are compared with the oscillation in the unit hydrograph. The optimal unit hydrograph is derived by combining the numerous rainfall-runoff data. The conclusions are as follows; 1)The oscillations in the derived unit hydrograph are reduced by combining the data from each flood event. 2) The reciprocals of the minimum eigen\value of XTX, 1/k and the condition number CN are increased when the oscillations are active in the derived unit hydrograph. 3)The parameter estimates are validated by extending the model to the Soyang river Dam site with elimination of the autocorrelation in the disturbances. Finally, this paper illustrates the application of the multiple regression model to drive an optimal unit hydrograph dealing with the multicollinearity and the autocorrelation which cause some problems.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.3
• /
• pp.61-69
• /
• 2008

The purpose of this study is to examine the success or failure on the balance beam in element group requirements posture which is bending salto side-ward tucked through kinetic analysis. The national team players were participated. The goal was to present training methods to coaches and athletes so as to provide scientifically useful information. The results from this study were summarized as below. When the performance was successful, the features of the body's center of gravity during the side somersault motion showed to spread from the center of the balance beam and the center of the gravity moved to the direction of the body's rotation. In the spring sections - event2 and 3, when the performance was successful, up/down fluctuation became more wider and increased air time. It supported the result that the projecting variable was higher than in failure trial. In addition, the right side hip joint angles and speed, and angular velocity as jumping up for a leap were larger than in failure trial. Those variables showed the optimal conditions for a leap. By increasing the speed of the upper limb from the shoulder and the speed of the shoulder joint angular velocity, the momentum was increased. Especially the right side shoulder joint angular velocity increased dramatically because the right leg was held. As to the side somersault motion, the angular momentum of successful trial with respect to x-axis was bigger than failed trial. It indicated that the increasing angular momentum with respect to x-axis was an important factor in flying motion. Besides, as to side somersault, the appropriate proportion of angular momentum with respect to y-axis and z-axis was a key to successful trails.

• Journal of Environmental Science International
• /
• v.21 no.8
• /
• pp.977-988
• /
• 2012

This study analyzed the characteristics of stormwater runoff by rainfall type in orchard areas and transportation areas for 2 years(2010~2011year). Effluents were monitored to calculate the Event Mean Concentrations(EMCs) and runoff loads of each pollutant. The pollutant EMCs by volume of stormwater runoff showed the ranges of BOD 0.9~13.6 mg/L, COD 13.7~45.2 mg/L, SS 4.1~236.4 mg/L, T-N 2.123~21.111 mg/L, T-P 0.495~2.214 mg/L in the orchard areas, and was calculated as BOD 2.3~22.5mg/L, COD 4.4~91.1 mg/L, SS 4.3~138.3 mg/L, T-N 0.700~13.500 mg/L, T-P 0.082~1.345 mg/L in the transportation areas. The correlation coefficient of determination in the orchard area was investigated in the order of Total Rainfall(0.81) > Total Runoff(0.76) > Rainfall Intensity(0.56) > Rainfall Duration(0.46) > Antecedent Dry Days(0.27). Also, in the case of the transportation area was investigated in the order of Total Rainfall (0.55) > Total Runoff(0.54) > Rainfall Intensity(0.53) > Rainfall Duration(0.24) > Antecedent Dry Days(0.14). As the result, comparing valuables relating to runoff of non-pollutant source between orchard areas and transportation areas, orchard area($R^2{\geq}0.5$ : X3, X4, X5) was investigated to have more influence of diverse independent valuables compared to the transportation area($R^2{\geq}0.5$ : X3, X4) and the difference of discharge influence factor by the land characteristics appeared apparently.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.1
• /
• pp.26-37
• /
• 2009

Recently rapid environmental changes due to desertification and industrialization in China make a threat to Korea, especially during Asian Dust Event (ADE). This study was aimed to compare symptoms and behaviors related to ADE between Korea and China. We conducted questionnaires on self-reported symptoms and behaviors before and during ADE. Korean and Chinese subjects were grouped into children, adults, and elderly by nation (n=791). Statistical analyses were performed by $X^2$-test, Fisher's exact test, t-test and chow's test for comparing differences between Korean and Chinese. We estimated the odds ratio for perceived symptoms during ADE by preventive behavior, using Generalized Estimation Equation (GEE). The study indicated that there were significant differences between symptoms in Korea and those in China such as cold, cough, and sore throat, especially in elderly. Preventive behaviors such as avoiding outdoor activity and wearing sunglasses were more often performed in China than Korea. However wearing mask was more often performed in Korea than China. After adjusting for age, sex, educational level, and smoking status, the odds ratio (OR) of dry cough symptom in Korea was significantly decreased by closing the windows and wearing a mask during ADE. In China, the OR of dry cough symptom was decreased by wearing a mask and avoiding outdoor activity. We found that China which had higher performance of preventive behavior showed lower prevalence of symptoms during ADE than Korea. Also preventive behaviors could affects prevalence of symptoms during ADE. This results suggest that preventive behavior. could reduce symptoms during ADE and there are needed for. more attentions to reduce a threat of ADE.

• Journal of Environmental Science International
• /
• v.11 no.5
• /
• pp.419-436
• /
• 2002

The current paper reports on the enhancement of O$_3$, CO, NO$_2$, and aerosols during the Asian dust event that occurred over Korea on 1 May 1999. To confirm the origin and net flux of the O$_3$, CO, NO$_2$, and aerosols, the meteorological parameters of the weather conditions were investigated using Mesoscale Meteorological Model 5(MM5) and the TOMS total ozone and aerosol index, the back trajectory was identified using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model(HYSPLIT), and the ozone and ozone precursor concentrations were determined using the Urban Ashed Model(UAM). In the presence of sufficiently large concentrations of NO$\sub$x/, the oxidation of CO led to O$_3$ formation with OH, HO$_2$, NO, and NO$_2$ acting as catalysts. The sudden enhancement of O$_3$, CO, NO$_2$ and aerosols was also found to be associated with a deepening cut-off low connected with a surface cyclone and surface anticyclone located to the south of Korea during the Asian dust event. The wave pattern of the upper trough/cut-off low and total ozone level remained stationary when they came into contact with a surface cyclone during the Asian dust event. A typical example of a stratosphere-troposphere exchange(STE) of ozone was demonstrated by tropopause folding due to the jet stream. As such, the secondary maxima of ozone above 80 ppbv that occurred at night in Busan, Korea on 1 May 2001 were considered to result from vertical mixing and advection from a free troposphere-boundary layer exchange in connection with an STE in the upper troposphere. Whereas the sudden enhancement of ozone above 100 ppbv during the day was explained by the catalytic reaction of ozone precursors and transport of ozone from a slow-moving anticyclone area that included a high level of ozone and its precursors coming from China to the south of Korea. The aerosols identified in the free troposphere over Busan, Korea on 1 May 1999 originated from the Taklamakan and Gobi deserts across the Yellow River. In particular, the 1000m profile indicated that the source of the air parcels was from an anticyclone located to the south of Korea. The net flux due to the first invasion of ozone between 0000 LST and 0600 LST on 1 May 1999 agreed with the observed ground-based background concentration of ozone. From 0600 LST to 1200 LST, the net flux of the second invasion of ozone was twice as much as the day before. In this case, a change in the horizontal wind direction may have been responsible for the ozone increase.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.1
• /
• pp.33-40
• /
• 2012

This paper proposes a method to implement biological early warning systems(BEWS). This system generates periodically data event using a monitoring daemon and it extracts the feature parameters from this data sets. The feature parameters are derived with 6 variables, x/y coordinates, distance, absolute distance, angle, and fractal dimension. Specially by using the fractal dimension theory, the proposed algorithm define the input features represent the organism characteristics in non-toxic or toxic environment. And to find a moderate algorithm for learning the extracted feature data, the system uses an extended learning algorithm(UChoo) popularly used in machine learning. And this algorithm includes a learning method with the extended data expression to overcome the BEWS environment which the feature sets added periodically by a monitoring daemon. In this algorithm, decision tree classifier define class distribution information using the weight parameter in the extended data expression. Experimental results show that the proposed BEWS is available for environmental toxicity detection.

• The Journal of the Korea Contents Association
• /
• v.13 no.10
• /
• pp.523-532
• /
• 2013

When the golf club hits the ground prior to making contact with the golf ball, we define it as 'fat shot'. The aim of this research was to investigate the difference between normal shot and fat shot in golf. Five candidates playing as recreational golfer participated in this research and they were all right-handed people. Time phase between each event, wrist cocking angle, elbow extension-flexion angle, backswing height, pelvis angle, thorax angle, L-GRF, R-GRF, pelvis linear velocity, pelvis angular velocity and COG path were calculated. For statistical analysis the paired T-test was used. An early un-cocking, an early right elbow extension and impact with leaving their weight behind foot were not reasons of fat shot. Backswing height, X-Factor, pelvis angle and thorax rotation angle were not different between normal shot and fat shot. But we could find a pattern of abrupt pelvic movement and weight shift to target direction just before impact in case of fat shot. In addition fat shot showed time-delayed and small value of pelvis linear velocity pattern to upward during downswing phase as against normal shot.

• Journal of Preventive Medicine and Public Health
• /
• v.46 no.5
• /
• pp.261-270
• /
• 2013

Objectives: This study investigated the socio-demographic characteristics and medical causes of death among meteorological disaster casualties and compared them with deaths from all causes. Methods: Based on the death data provided by the National Statistical Office from 2000 to 2011, the authors analyzed the gender, age, and region of 709 casualties whose external causes were recorded as natural events (X330-X389). Exact matching was applied to compare between deaths from meteorological disasters and all deaths. Results: The total number of deaths for last 12 years was 2 728 505. After exact matching, 642 casualties of meteorological disasters were matched to 6815 all-cause deaths, which were defined as general deaths. The mean age of the meteorological disaster casualties was 51.56, which was lower than that of the general deaths by 17.02 (p<0.001). As for the gender ratio, 62.34% of the meteorological event casualties were male. While 54.09% of the matched all-cause deaths occurred at a medical institution, only 7.6% of casualties from meteorological events did. As for occupation, the rate of those working in agriculture, forestry, and fishery jobs was twice as high in the casualties from meteorological disasters as that in the general deaths (p<0.001). Meteorological disaster-related injuries like drowning were more prevalent in the casualties of meteorological events (57.48%). The rate of amputation and crushing injury in deaths from meteorological disasters was three times as high as in the general deaths Conclusions: The new information gained on the particular characteristics contributing to casualties from meteorological events will be useful for developing prevention policies.

• Clinical and Experimental Pediatrics
• /
• v.59 no.6
• /
• pp.280-284
• /
• 2016

Cerebral cavernous malformation (CCM) is a vascular malformation characterized by abnormally enlarged capillary cavities without any intervening neural tissue. We report 2 cases of familial CCMs diagnosed with the CCM1 mutation by using a genetic assay. A 5-year-old boy presented with headache, vomiting, and seizure-like movements. Brain magnetic resonance imaging (MRI) revealed multiple CCM lesions in the cerebral hemispheres. Subsequent mutation analysis of his father and other family members revealed c.940_943 del (p.Val314 Asn315delinsThrfsX3) mutations of the CCM1 gene. A 10-month-old boy who presented with seizure-like movements was reported to have had no perinatal event. His aunt was diagnosed with cerebral angioma. Brain and spine MRI revealed multiple angiomas in the cerebral hemisphere and thoracic spinal cord. Mutation analysis of his father was normal, although that of the patient and his mother revealed c.535C>T (p.Arg179X) mutations of the CCM1 gene. Based on these studies, we suggest that when a child with a familial history of CCMs exhibits neurological symptoms, the physician should suspect familial CCMs and consider brain imaging or a genetic assay.