Earticle

최근 국내‧외적으로 많은 지진이 발생하고 있는 상황에서, 우리나라의 건물은 내진설계 및 지진피해에 매우 취약한 상황이다. 따라서 현 연구의 목적은 건물에 대한 지진취약도 등급화 및 위험건물 밀도분석을 수행하는 효과적인 방법을 발굴 하고 이를 모델화하여, 시범지역(서울시)자료를 활용해 검증해 보는데 있다. 이를 위해 활용된 두 가지 모델링 기법 중, 통계 분석 기법의 예측정확도는 87%였고, 머신러닝 기법은 Random Forest모델의 예측정확도가 가장 높았으며, 해당 모델의 Test Set 정확도는 97.1%로 도출되었다. 분석결과, 구별 등급화 결과는 광진구와 송파구가 상대적으로 위험하다고 예측되었 으며, 위험건물 밀도분석은 서초구, 관악구, 강서구가 상대적으로 위험하다고 예측되었다. 최종적으로, 통계분석 기법을 활용 한 분석결과가 머신러닝 기법을 활용한 분석결과보다 위험하게 도출되었으나, 우리나라에서는 지진 강도 6.5(MMI)가 내진설 계의 기준인데, 서울시 건물의 약 18.9%가 내진설계 되어있는 것으로 확인된 것을 고려하면, 머신러닝 기법의 결과가 더 정 확할 것으로 예측되었다. 현 연구는 인구 및 인프라와 경찰서, 소방서 등을 고려 않은 오직 건물만을 고려한 한계점이 있으며, 해당 한계를 포함해 수행하면 더욱 포괄적인 연구가 될 것이다.

In the recent period, there have been numerous earthquakes both domestically and internationally, and buildings in South Korea are particularly vulnerable to seismic design and earthquake damage. Therefore, the objective of this study is to discover an effective method for assessing the seismic vulnerability of buildings and conducting a density analysis of high-risk structures. The aim is to model this approach and validate it using data from pilot area(Seoul). To achieve this, two modeling techniques were employed, of which the predictive accuracy of the statistical analysis technique was 87%. Among the machine learning techniques, Random Forest Model exhibited the highest predictive accuracy, and the accuracy of the model on the Test Set was determined to be 97.1%. As a result of the analysis, the district rating revealed that Gwangjin-gu and Songpa-gu were relatively at higher risk, and the density analysis of at-risk buildings predicted that Seocho-gu, Gwanak-gu, and Gangseo-gu were relatively at higher risk. Finally, the result of the statistical analysis technique was predicted as more dangerous than those of the machine learning technique. However, considering that about 18.9% of the buildings in Seoul are designed to withstand the Seismic intensity of 6.5 (MMI), which is the standard for seismic-resistant design in South Korea, the result of the machine learning technique was predicted to be more accurate. The current research is limited in that it only considers buildings without taking into account factors such as population density, police stations, and fire stations. Considering these limitations in future studies would lead to more comprehensive and valuable research.

Purpose: We aimed to evaluate the accessibility and equity of automated external defibrillators (AEDs)in areas with a high concentration of older adults and to propose evidence-based policy directions usinggeographic information systems (GIS). Methods: For the secondary analysis, multiple datasets were integrated from the Korea's NationalGeographic Information Institute, the Ministry of the Interior and Safety, the Suwon Fire Department,and the Suwon Southern Fire Station, including continuous digital topographic maps, demographicstatistics, AED locations, road networks, and out-of-hospital cardiac arrest incidence data. The clusteringand spatial heterogeneity of AED deployment were examined using kernel density estimation andspatial autocorrelation analysis. Service areas reflecting the walking speeds of older adults weredelineated, and equity was assessed using the Gini coefficient. A two-step floating catchment areaanalysis was used to provide supply-to-demand ratios and accessibility indices. Results: AEDs exhibited clustered patterns centered on public locations, and several areas were identified as potential service blind spots, revealing inequities at the neighborhood level. Several AED siteswere insufficient for the local older-adult population, and only a subset of areas demonstrated relativelyhigh accessibility indices. Conclusion: As the population age structure shifts toward older age groups, AED policy criteria should beredesigned to reflect the mobility and accessibility of older adults. Implementing mixed relocationstrategies that incorporate age-friendly criteria, conducting periodic policy performance evaluations,and enhancing AED visibility and tailored education that accounts for the cognitive characteristics ofolder adults will contribute to improving the health of older populations.

Background: As the number of households raising companion dogs increases, the pet genetic analysis market also continues to grow. However, most studies have focused on specific purposes or native breeds. This study aimed to collect genomic data through single nucleotide polymorphism (SNP) chip analysis of companion dogs in South Korea and perform genetic diversity analysis and SNP annotation. Methods: We collected samples from 95 dogs belonging to 26 breeds, including mixed breeds, in South Korea. The SNP genotypes were obtained for each sample using an Axiom™ Canine HD Array. Quality control (QC) was performed to enhance the accuracy of the analysis. A genetic diversity analysis was performed for each SNP. Results: QC initially selected SNPs, and after excluding non-diverse ones, 621,672 SNPs were identified. Genetic diversity analysis revealed minor allele frequencies, polymorphism information content, expected heterozygosity, and observed heterozygosity values of 0.220, 0.244, 0.301, and 0.261, respectively. The SNP annotation indicated that most variations had an uncertain or minimal impact on gene function. However, approximately 16,000 non-synonymous SNPs (nsSNPs) have been found to significantly alter gene function or affect exons by changing translated amino acids. Conclusions: This study obtained data on SNP genetic diversity and functional SNPs in companion dogs raised in South Korea. The results suggest that establishing an SNP set for individual identification could enable a gene-based registration system. Furthermore, identifying and researching nsSNPs related to behavior and diseases could improve dog care and prevent abandonment.

Background: As per guidelines for treating dyslipidemia, the recommended low-density lipoprotein cholesterol (LDL-C) level in extremely high-risk patients, including those with coronary artery diseases is <55 mg/dL. Although this recommendation has been adopted in the guidelines for dyslipidemia in various countries, there is limited evidence of its efficacy in reducing cardiovascular diseases (CVDs), especially among East Asian patients. This study aimed to investigate whether an LDL-C value below 55 mg/dL is associated with decreased risk of CVDs. Methods: Seven clinical trials including 50,970 patients that compared intensive lipidlowering therapy with less therapy or placebo in patients who had >6 months of follow-up, those with a sample size of ≥150 were selected as the final literature for analysis. Risk ratios (RR) using random effects were represented with 95% confidence intervals (CI) for the reliability of the results. Results: An LDL-C level of <55 mg/dL was related to significantly reduced events of major CVDs (RR: 0.88; 95% CI: 0.80-0.98) and myocardial infarction (RR: 0.81; 95% CI: 0.73-0.90) and a reduced risk of ischemic stroke (RR 0.79; 95% CI 0.69-0.89, mean follow-up=2 years). However, an LDL-C level below 55 mg/dL did not reduce the incidence of CVD in intensive therapy in East Asian patients. Conclusions: A goal LDL-C value below 55 mg/dL was identified to be related to a decreased risk of developing CVD. However, the relation to LDL-C below 55 mg/dL with a decreased risk of CVD was not observed in East Asian patients.

본 연구에서는 염분과 온도차에 의한 밀도류를 해석하기 위하여 기존의 3차원 파동장 모델(LES-WASS-3D ver. 1.0)을 토대로 염분과 온도에 관한 상태방정식 및 3차원 이류-확산 방정식을 도입하여 새로운 수치모델(LES-WASS-3D ver. 2.0)을 개발하였다. 새롭게 개발한 수치모델의 적용성을 검토하기 위하여 기존의 수리모형실험결과와 비교 분석하였다. 그 결과, 이류-확산하는 해수의 형태 및 연직 염분농도 뿐만 아니라 방출하는 온수의 유속 및 온도를 매우 잘 재현하는 것으로 나타났다. 이로써 본 연구에서 개발한 수치모델의 타당성 및 유효성이 검증되었다.

In order to analyze the density current due to salt and temperature difference, this study develops new numerical model (LES-WASS-3D ver. 2.0) by introducing state equation for salt and temperature and 3D advection-diffusion equation to existing 3D numerical wave tank (LES-WASS-3D ver. 1.0). To verify the applicability, the newly-developed numerical model is analyzed comparing to the experimental result of existing numerical model. In the result, it well implement the behavior and vertical salt concentration of advected and diffused seawater as well as flow velocity and temperature of the discharged warm water. This confirms the validity and effectiveness of the developed numerical model.

수공구조물의 설계를 위한 확률강우량의 산정방법은 크게 지점빈도해석과 지역빈도해석으로 구분된다. 일반적으로 확률강우량은 대상유역에 위치하는 강우관측소에서 관측된 강우량자료를 지점빈도해석으로 추정하게 된다. 지점빈도해석을 통한 확률강우량을 산정하기 위해서는 충분한 기간 동안의 관측된 강우량자료의 확보가 필수적이라 할 수 있으나 관측자료의 부족으로 인해 매개변수의 편의가 발생할 수 있다. 따라서 부족한 강우자료를 보완하고 안정적인 확률강우량을 산정하기 위한 방안으로 지역빈도해석이 추천되어지고 있다. 따라서 본 연구에서는 우리나라 강우관측소의 위치 및 시간강우량 특성을 이용한 군집분석을 수행하여 강우관측소를 군집화 하였다. 군집화 된 강우관측소를 대상으로 L-moment 법을 통해 산정한 매개변수를 이용하여 각각의 지역별로 불일치성 및 이질성 검정을 통한 지역구분을 수행하여 우리나라 강우관측소를 6개 지역으로 구분하였다. 구분된 지역별로 L-moment 법, 지수홍수법 및 변동핵밀도함수를 적용한 지역빈도해석을 수행하여 각각 확률강우량을 산정하여 비교하였다. 분석결과에서 변동핵밀도함수를 이용한 지역빈도해석은 다른 기법에서 적합한 확률분포형 결정이 어려운 경우 등에 충분히 활용할 수 있는 것으로 나타났다.

The techniques to calculate the probability precipitation for the design of hydrological projects can be determined by the point frequency analysis and the regional frequency analysis. Probability precipitation usually calculated by point frequency analysis using rainfall data that is observed in rainfall observatory which is situated in the basin. Therefore, Probability precipitation through point frequency analysis need observed rainfall data for enough periods. But, lacking precipitation data can be calculated to wrong parameters. Consequently, the regional frequency analysis can supplement the lacking precipitation data. Therefore, the regional frequency analysis has weaknesses compared to point frequency analysis because of suppositions about probability distributions. In this paper, rainfall observatory in Korea did grouping by cluster analysis using position of timely precipitation observatory and characteristic time rainfall. Discordancy and heterogeneity measures verified the grouping precipitation observatory by the cluster analysis. So, there divided rainfall observatory in Korea to 6 areas, and the regional frequency analysis applies index-flood techniques and L-moment techniques. Also, the probability precipitation was calculated by the regional frequency analysis using variable kernel density function. At the results, the regional frequency analysis of the variable kernel function can utilize for decision difficulty of suitable probability distribution in other methods.

A연속류도로는 교통량-속도-밀도 간에 상호 밀접한 관계가 있기 때문에 연결로교통류가 본선에 합류하게 되면 속도나 밀도가 변할 뿐만 아니라 이들 간의 상관관계를 나타내는 모형식도 달라진다. 따라서, 본 연구는 합류영향권역에서 시공간적으로 연속된 교통자료를 이용하여 속도-밀도 변수간의 상관관계 변화구간을 파악하고, 구간별 변화내용을 분석하였다. 분석결과, 상류 및 합류구간에서는 "Underwood"모형의 지수형태를 보이며, 합류구간을 통과한 하류구간에서는 "Greenshields"모형의 직선형태를 나타내었다. 속도-밀도 상관관계가 변화된 하류변화구간은 연결로와 접속한 3차로의 합류 종점부를 기점으로 하류 100m~500m 범위에서 내측차로로 갈수록 점차 하류방향으로 이동하는 현상을 보였다. 또한, 상류구간, 합류구간, 하류변화구간은 속도-밀도 모형에서 자유속도(상수)와 혼잡밀도에 대한 자유속도비(기울기)가 통계적으로 서로 다른 이질적인 교통류로 나타났다.

Uninterrupted facility - since there is a close relationship between traffic volume, speed and density -, when a ramp traffic flow merges into the main line, will change the traffic speed or density, and the corresponding correlational model equation will be changed. Thus, this study, using time and space-series traffic data on areas under the influence of such a merging, identified sections which changed the correlation between speed and density variables, and examined such changes. As a result, the upstream and merging sections showed the "Underwood"-shaped exponent, and the downstream after passing the merging section showed a straight line "Greenshields" model. The downstream section which changed the correlation between speed and density showed a gradual downstream movement phenomenon within 100 m-500 m from the end of the third lane linking with the ramp, as the traffic approached the inner lanes. Also, the upstream section, merging section, and downstream section involving a change showed heterogeneous traffic flows which, in the speed-density model, have a statistically different free flow speed (constant) and a different ratio of free flow speed to jam density (gradient).

Purpose: This study aims to suggest clinical basis of physical therapy to skeletal system complication in type II diabetic patients through a variety of analysis methods. Methods: 75 subjects(type II diabetic patients; age from 40 to 80) of this study were participated in BMD(Bone Mineral Density) and Dual energy X-ray absorptiometry, blood test to their skeletal system. Results: Incidence of osteopenea was higher than normal group as women(91.2%) and men(53.5%) in diabetes group. However, women were showed no significantly difference in comparison group. Above age 60(in diabetes group; men and women) showed to highly incidence of osteopenea as well as significantly difference in osteopenea(peripheral neuropathy). As a result of analyzing blood through presence and absence of osteopenea in diabetes group, men were showed significantly difference in DPD/creatinine ratio and women were showed significantly difference in Alkaline phosphatase, Corrected Calcium. Conclusion: This study shows that decreased BMD and increased osteopenea through type II diabetes. Women were particularly lower BMD and higher incidence of osteopenea than men and men influence of type II diabetes on change of BMD was greater than women.

The distribution of magnetic flux density of electro-magnetic chucks may clarify the clamping characteristics which are strongly related to the machining efficiency and machining accuracy in a surface grinder. Therefore the distribution of the normal and the tangential components of magnetic flux density has been analyzed theoretically. It appears that the normal and the tangential components of magnetic flux density increase as the ratio of the separator width to the pitch e/p decreases. The results seem to increase the uniformity and stability of normal component of magnetic flux density for the decreased e/p.

The MIAB welding uses a rotating arc as its heat source and is known as an efficient method fur pipe butt welding. The arc is rotated around the weld line by the electro-magnetic force resulting from the interaction of arc current and magnetic field. The electro-magnetic force is affected by magnetic flux density, arc current, and arc length. Especially, the magnetic flux density is an important factor on arc rotation and weld quality. This paper presents a 2D finite element model for the analysis of magnetic flux density in the actual welding conditions. The magnetic flux density is mainly dependent on gap between two pipes, the position of coil from gap center, exciting current, and relative permeability. Thus, the relations between magnetic flux density and main factors were investigated through experiment and analysis. Experiments were performed for the steel pipes(48.1mm O.D and 2.0mm thickness). The analysis results of magnetic flux density reveal that it increases with increasing exciting current, increasing relative permeability, decreasing distance from gap center to coil, and decreasing gap size. It is considered that the results of this study can be used as important data on the design of coil system and MIAB welding system.

우리나라는 수공구조물 설계할 때 강우빈도해석과 강우-유출 모형으로 홍수량을 산정하여 사용하고 있다. 그러나 강우자료의 확률분포 및 자료기간 등에 따른 매개변수 추정에 많은 불확실성이 존재하나 이를 고려한 해석은 이루어지지 않고 있다. 이러한 점에서 Gumbel 분포형과 확률가중 모멘트법을 기준으로 확률강우량의 신뢰구간을 평가함과 동시에 매개변수의 불확실성을 평가하는데 있어서 우수한 성능을 발휘하는 Bayesian방법을 도입하여 서울지역의 확률강우량의 불확실성을 정량적으로 평가하였다. 두 가지 방법의 비교결과 확률가중모멘트법의 신뢰구간이 Bayesian 방법의 불확실성 구간보다 전반적으로 크게 나타났다. 신뢰구간의 경우 정규분포를 따르기 때문에 좌우대칭의 형태를 갖는 반면에 Bayesian 방법의 불확실성은 Gumbel 분포로부터 유도되어, 보다 현실적인 불확실성 평가가 가능하였다. 자료의 구간 및 기간에 따른 확률강우량의 불확실성을 평가한 결과 자료에 증가에 따른 불확실성 감소를 확인할 수 있었으며, Bayesian 방법이 자료 증가에 따른 불확실성 범위 감소가 보다 뚜렷하게 나타나는 것을 확인할 수 있었다.

Rainfall-runoff modeling in conjunction with rainfall frequency analysis has been widely used for estimating design floods in South Korea. However, uncertainties associated with underlying distribution and sampling error have not been properly addressed. This study applied a Bayesian method to quantify the uncertainties in the rainfall frequency analysis along with Gumbel distribution. For a purpose of comparison, a probability weighted moment (PWM) was employed to estimate confidence interval. The uncertainties associated with design rainfalls were quantitatively assessed using both Bayesian and PWM methods. The results showed that the uncertainty ranges with PWM are larger than those with Bayesian approach. In addition, the Bayesian approach was able to effectively represent asymmetric feature of underlying distribution; whereas the PWM resulted in symmetric confidence interval due to the normal approximation. The use of long period data provided better results leading to the reduction of uncertainty in both methods, and the Bayesian approach showed better performance in terms of the reduction of the uncertainty.

에너지 부족과 지구온난화 문제들을 동시에 만족 시킬 수 있는 바이오매스 자원의 효율적 이용을 위해 국내에서 공급받을 수 있는 농산, 임산, 축산, 도시 생활 폐기물 등의 바이오매스 자원량을 기존에 발표된 자료들을 통합하여 분석하였다. 또한 자원량을 각 지역별 면적으로 나눈 지역별 바이오매스 자원 밀집도를 구하였다. 바이오매스 발생량의 분석은 가용할 수 있는 자원 잠재량을 파악할 수 있으나 지역별 밀집도 분석은 바이오매스 수집에 따른 비용을 고려한 바이오매스 자원 이용 가능성을 예측할 수 있도록 도와주고 바이오매스 자원에 따른 적절한 전환 공정 선택도 예측할 수 있도록 해준다.

The biomass resources is one of promising ways to solve energy exhaustion issues and global warming issues at the same time. To evaluate domestic biomass resources potential such as agricultural wastes, forestry wastes, livestock wastes and municipal solid wastes, statistics data from various organizations were collected and analyzed in this study. Also, space energy densities of each districts in Korea were calculated and analyzed. The results from the evaluation of biomass energy potential and space energy densities in Korea might be useful to estimate the availability of biomass energy conversion processes and to choice a appropriate process to convert domestic biomass into energy.

본 연구는 국가간 공동연구 네트워크가 기술 지식의 확산에 어떠한 영향을 미치는 가와 네트워크 상에서 중심성이 높은 국가가 새로운 기술을 얼마나 받아들이는지 분석하고 그 의미를 찾는 것을 목적으로 한다. 이를 위해 이차전지 분야와 전기 자동차 분야 논문 정보를 이용하여 연도별 국가간 공동연구 네트워크 밀도와 참여국가 수를 측정하고 변수간의 회귀분석을 수행하였다. 분석결과, 이차전지 분야 공동연구 네트워크 밀도가 증가할수록 참여국가 수는 선형관계로 증가하는 것으로 나타났다. 또한 공동연구 네트워크 상에서 연결정도 중심성이 높은 국가들이 중대형 이차전지 분야 개발을 주도하고 있는 것으로 나타났다. 반면에 전기 자동차 분야의 경우, 네트워크 밀도값은 증가 추세가 나타나지 않지만, 참여국가 수는 증가하고 있는 것으로 나타났다. 이는 기술 확산을 촉진하는데 있어서, 국가간 공동연구가 중요한 역할을 하지만 필요충분 조건은 아닌 것으로 분석되었다. 이러한 결과는 기술 성장에 있어서 반드시 필요한 기술 확산을 촉진하는 요인을 통계적으로 검증하였다는 점에서 의의가 있으나, 네트워크 상에서 중심적 역할에 대한 지표를 연결정도 중심성 만으로 측정하였다는 점과 네트워크 밀도가 행위자간 상호작용에 있어서 반드시 두 행위자간 관계만을 측정한다는 점에서 연구의 한계가 존재한다. 따라서 향후 다수의 연구자간 상호작용을 측정할 수 있는 방안에 대한 연구가 필요하다.

The purpose of this study is to analyze how a joint research network between countries affects the diffusion of technology information and how much countries with high centrality on the network accept new technology and to seek their meaning. With this aim, the joint research network density between countries by year and the number of participating countries were measured using thesis information regarding the secondary battery field and the electric vehicle field, and a regression analysis of relevant variables was conducted. As a result of the analysis, the greater the joint research network density in the secondary battery field, the higher the number of participating countries in a linear relationship. Also, on the joint research network, countries with high degree centrality were discovered to have led development in the mid to large size secondary battery field. Meanwhile, for the electric vehicle field, although there appeared no increase in the network density value, the number of participating countries was found to have increased. This was analyzed that joint research between countries was not a necessary and sufficient condition although it played a crucial role in promoting technology diffusion. Such a result is meaningful in that it verified promoting factors for essential technology diffusion statistically; however, with this research, there exist limitations that the index of a central role on the network was measured only with degree centrality and that only the relationship between two players was measured for network density in interactions between players. Accordingly, it is necessary to carry out research into a method to measure interactions among multiple researchers in the future.

밀도가 큰 유체의 유입으로 인한 소규모저수지의 바닥밀도류에 의한 순환이 수치해에 의하여 해석된다. 밀도류전면이 하류경계에 도달하기전에는 밀도류전면의 이동에 따라 침강점 하류에 형성된 반시계방향 와의 이동에 의하여 저수지내 순환과 혼합이 이루어지며, 밀도류전면이 하류경계에 도달한 후에는 하류경계에서 밀도류의 상승으로 인한 일종의 내부파가 형성되고 이 파의 상 하류 반복 전파됨에 따라 저수지내 혼합이 이루어지면서 밀도층의 두께는 증가한다. 하류경계에서 유출되는 유체의 희석은 유입밀도후르드수 Fre, 저수지길이, 시간의 함수이며 유출유체의 밀도가 일정값에 도달되는 시간은 저수지길이가 길수록, Fre가 작을수록 증가하는 것으로 나타났다.

The ciculation due to bottom density current produced by a dense inflow into a small reservoir is analysed by numerical scheme. Before the front of the density current arrives at the downstream end, the mixing in the reservoir is mainly caused by the anticlockwise vortex formed at the downstream of plunging point along the movement of bottom density current. Upon the arrival of the front of the density current at the downstream end an internal surge is created through an internal hydraulic jump. With repeated propagation of the internal surge back and forth the mixing in the reservoir is progressed and the thickness of dense layer is increased upward. The dilution of the overflow at downstream end is found to depend on inflow densimetric Froude number, reservoir length and elapsed time. The time required for the overflow to attain a specified dilution increases as reservoir length increases and Fre decreases.

최근 CCTV 영상을 기반으로 인파사고를 예방하는 방안이 추진되고 있다. 그러나 CCTV는 공간적 한계점이 있어 이를 보완하기 위한 연구가 필요한 실정이다. 본 연구에서는 드론 영상 을 사용하여 보행자의 밀도를 측정하는 연구를 수행하였다. 기존 연구문헌을 통해 군중의 인 파사고 임계값인 1m2당 6.7명을 위험수준으로 선정하였다. 또한 드론의 파라미터를 도출하기 위해 선행연구를 수행한 결과, 고도 20m, 각도 60°에서 보행자의 인식률이 높은 것으로 나타났 다. 이후 선행연구를 기반으로 보행자가 밀집한 대상지를 선정하여 밀집도를 측정한 결과, 단 위 면적당 0.27~0.30명 수준으로 나타났다. 본 연구를 통해 드론 영상을 사용하여 대상지의 보 행자 밀집도에 따른 위험수준 측정이 가능한 것으로 확인되었으며, 향후 인파사고 안전관리 대체 수단으로 활용이 가능할 것으로 판단된다.

Recently, the use of CCTV to prevent crowd accidents has been promoted, but research is needed to compensate for the spatial limitations of CCTV. In this study, pedestrian density was measured using drone footage, and based on a review of existing literature, a threshold of 6.7 people/m2 was selected as the cutoff risk level for crowd accidents. In addition, we conducted a preliminary study to determine drone parameters and found that the pedestrian recognition rate was high at a drone altitude of 20 meters and an angle of 60°. Based on a previous study, we selected a target area with a high concentration of pedestrians and measured pedestrian density, which was found to be 0.27~0.30 per m2. The study shows it is possible to measure risk levels by determining pedestrian densities in target areas using drone images. We believe drone surveillance will be utilized for crowd safety management in the near future.

This study was to evaluate the body composition and bone mineral density according to aging in adult and investigated the relationship between various parameters such as body mass index(BMI), bone mineral density(BMD), bone mineral content(BMC), lean body mass(LBM), fat mass(FM) and the value obtained from dual energy X-ray absorptiometry(DEXA). The subjects were composed of healthy adult male and female who were $20^{\sim}73$ years old and they were divided three group according to age (A group : 20-39 yrs., B group : 40-59 yrs., C group : more than 60 yrs.). The conclusion derived from statistical analysis was as follows : 1. Bone mineral content and density were significantly affected by lean body mass(relatively, R=0.85 - 0.63). 2. There was significant difference among age groups in total bone mineral density. 3. There was significant difference among age groups in bone mineral content of male and female. 4. Lean body mass is diminished according to age, but there was not significant difference among age groups. 5. Fat mass of A group in male had the highest mass and followed by C group and B group. In female groups, fat mass of A group had the highest mass and followed by B group and C group. Abdominal fat mass is increased according to age. This result suggest that aging was closely relation with loss of muscle mass, bone mineral density and bone mineral content.

PURPOSE: This study conducted aA forward-looking study of elite water polo athletes, who trained at National Training Center, was conducted to determine the correlation between the incidence of sports injuries and the bone density among national water polo players. METHODS: Data on the general characteristics of all study subjects were analyszed usingin descriptive statistics. The incidence of sports injuries was calculated from the incidence of sports injuries per 1,000 hours and the incidence of sports injuries resulting from exposure to 1,000 training sessions. The incidence of all sports injuries was calculated with a 95% confidence interval. Furthermore, Pearson's correlation was calculated conducted to determine the correlation between sports injuries and bone density, bone mass and body composition. RESULTS: Water polo athletes suffered a total of 127 sports injuries in the three-year period, while the athletes suffered 3.5 sports injuries each year. The Ooverall injury rate of 3.2(95% CI 2.68-3.81) per 1,000h, 18.0(15% CI 14.89-21.16) of sports injuries per 1,000AE. For all athletes, 50.4% of the injuries were classified as mild, followed by moderate (26.8%) and severe (22.8%). The lower the bone density in all areas of sports injuries, the higher the incidence of sports injuries. In addition, and the lower the bone mass in all areas except for light injuries, the higher the incidence of sports injuries. CONCLUSION: In tThe correlation between sports injuries and bone density and bone composition of water polo athletes, revealed a significant correlation between the bone density and bone mass were statistically significant, and the lower the bone density and bone mass, the higher the incidence of sports injuries.

Objectives: Scientific verification for health effects has been constantly demanded through the forest healing factors. In this study, phytoncide concentration which is one of the forest healing factors, was investigated according to stand density, season and visiting time, and analyzed correlation with micrometeorology factors. Methods: Total volatile organic compounds (TVOCs) and Natural volatile organic compounds (NVOCs) were collected using a measuring instrument which is connected to an air pump with the Tenax TA tube. The 32NVOCs were selected through the detailed criteria of adequacy assessment for recreational forest. The statistical analysis (correlation and stepwise regression analysis) was conducted between phytoncide concentration and micrometeorology factors. Results: NVOCs concentration linearly increased according to stand density. The high level showed in the summer (p<0.05), and there is no significant difference according to visiting hours of the Healing forest. NVOCs is a negative correlation with solar radiation, PAR and wind direction, and a positive correlation with relative humidity and temperature (p<0.01). NVOCs increased following the increase of humidity and temperature ($R^2=0.55$). Conclusions: Phytoncide linearly increased according to stand density, and showed the correlation significantly with microclimate factors. In future, these results will be utilized as a basic material to promote the generation of phytoncide, which positively influences human health promotion and manage the forest welfare space.

PURPOSES : This study deals with the traffic accidents classified by the traffic analysis zone. The purpose is to develop the accident density models by using zonal traffic and socioeconomic data. METHODS : The traffic accident density models are developed through multiple linear regression analysis. In this study, three multiple linear models were developed. The dependent variable was traffic accident density, which is a measure of the relative distribution of traffic accidents. The independent variables were various traffic and socioeconomic variables. CONCLUSIONS : Three traffic accident density models were developed, and all models were statistically significant. Road length, trip production volume, intersections, van ratio, and number of vehicles per person in the transportation-based model were analyzed to be positive to the accident. Residential and commercial area ratio and transportation vulnerability ratio obtained using the socioeconomic-based model were found to affect the accident. The major arterial road ratio, trip production volume, intersection, van ratio, commercial ratio, and number of companies in the integrated model were also found to be related to the accident.