본 연구는 우적크기분포의 통계적 특성과 변동성을 알아보기 위하여, 2011-2012년 대구지역 2차원광학우적계 자료를 분석하여 Marshall and Palmer(1948)의 우적크기분포 특성과 비교하였다. 우적크기분포의 특성변수로 강우강도(R), 레이더 반사도(Z), 보편특성수농도(N0'), 보편특성직경(Dm')을 계산하였다. 또한 스케일링 법칙을 사용하여 우적크기분포의 정규화 여부를 확인하였다. 분석 결과, 대구지역의 우적크기분포는 평균적으로 log10N0' =2.37, Dm' =1.04 mm이며 형태 인자의 경우 c =2.37, μ =0.39를 가졌다. 대구지역의 우적크기분포를 Marshall and Palmer의 우적크기분포로 가정하여 계산한 결과, 평균적으로 log10N0' =2.27, Dm' =0.9 mm, c =1, μ =1를 가졌다. 이 차이로부터 대구지역 우적크기분포는 Marshall and Palmer(1948)의 우적크기분포보다 통계적으로 더 높은 액체수함량을 가짐을 알 수 있다. 우적크기분포의 형태를 비교한 결과, 대구지역 우적크기분포는 위로 볼록한 모양이었다. Z > 45 dBZ를 기준으로 우적크기분포 형태에 변화가 있었다. 35 dBZ ≤ Z > 45 dBZ에서 대구지역 우적크기분포 특성은 해양성 기후대와 유사하였으나 Z > 45 dBZ에서는 Marshall and Palmer의 우적크기분포 특성과 유사하였다.

The chemical structures of perfluorinated compounds(PFCs) have unique properties such as thermal and chemical stability that make them useful components in a wide variety of consumer and industrial products. Two of these PFCs, perfluorooctane sulfonate(PFOS) and perfluorooctanoic acid(PFOA), have received attention and were the most commonly detected. In this study it was analyzed the concentrations of 8 PFCs in samples were collected from drinking water treatment plants for 5 years(2012-2016). PFOS and PFOA were also high concentration and frequency. The mean concentrations of PFOA and PFOS were detected 0.0026-0.0069 μg/L and 0.0009-0.0024 μg/L in samples from drinking water treatment plants. These were relatively lower or similar compared to PFOS concentrations in Osaka(Japan). In general, these levels are below health-based values set by international authoritative bodies for drinking water. These results will be serve as the first monitoring data for PFCs in drinking water and be useful for characterizing the concentration distribution and management of PFCs in future studies.

An analysis of recent studies and a field survey were conducted to investigate the distribution of the exotic species Ophraella communa LeSage (Coleoptera, Chrysomelidae) and the results’ applicability for biological control against ragweed, which disturbs the island’s ecosystem. The ragweed beetle (O. communa) can be found anywhere on the host plant Ambrosia artemisiifolia L., which grows in Jeju Island. Moreover, ragweed beetles possess the following characteristics: a high host plant specificity, a high-temperature resistance, an excellent mobility, and multivoltinism. Ragweed is extensively distributed and gradually expands its habitat further on Jeju Island. For this reason, it is recommended to take advantage of O. communa for the biological control of ragweed instead of pesticides or direct removal, considering that Jeju is endowed with many natural reserves and unique insular traits.

In order to investigate distribution of vascular plants along elevational gradient in the Nodong valley of Gyebangsan, vascular plants of eight sections with 100-meter-high were surveyed from the Auto-camping site (800 m) to the top of a mountain (1,577 m). There were a total of 382 taxa: 89 families, 234 genera, 339 species, 7 subspecies, 34 varieties, and 2 forms. As a result of analyzing the pattern of species richness, it showed a reversed hump-shaped with minimum richness at mid-high elevation. As a result of analyzing habitat affinity types, the proportion of forest species increased with increasing elevation. But, the ruderal species decreased with increasing elevation, and then increased at the top of a mountain. As for the proportion of life forms, the annual herbs gradually decreased with increasing elevation, but it did not appear between 1,300 m and 1,500 m and then increased at the top of a mountain. The trees gradually increased with elevation and decreased from 1,300~1,400 m. The vascular plants divided into four groups by using DCA. The arrangement of each stands was arranged in order from right to left on the Ⅰ axis according to the elevation. The distribution of vascular plants is determined by their own optimal ranges of vegetation. Also, rise in temperature due to climate change affects the distribution of vascular plants, composition, and diversity. Therefore, continuous monitoring is necessary to confirm ecological and environmental characteristics of vegetation, distribution ranges, changes of habitat. Furthermore, plans for conservation and management based on these data should be prepared according to climate change.

2010년 에야피얏라흐요쿳(Eyjafjallajökull) 화산 분화에 의한 화산재의 확산은 유럽 전역의 항공기 운항을 중단시켰으며 전 지구적인 사회 및 경제적 관심을 불러일으켰다. 또한 국내에서도 한반도에 영향을 미칠 수 있는 주변 화산 분화 활동과 백두산 분화 전조현상에 대한 연구 활동이 꾸준히 진행되고 있다. 화산재 확산 예측은 기상데이터를 이용한 확산 수치 모형이 일반적으로 이용되는데, 기상데이터와 수치 모형의 불확실성을 줄이기 위한 방법으로 앙상블 분석이 주로 활용되고 있다. 본 연구에서는 오일러 방법 기반의 수치 모형에 의한 화산재 확산 해석을 유사한 기상장을 갖는 날짜에 대하여 수행했으며, 앙상블 분석을 통한 불확실성 감소 방법을 제시하였다. 특히 대부분의 앙상블 방법은 현장 관측데이터를 주요 데이터로 간주하는데 반하여, 화산재의 현장 측정은 얻기가 매우 어려운 상황이다. 그러므로 신뢰도 앙상블 평균(REA; Reliability Ensemble Averaging) 방법의 과거기간 시나리오의 모의 변수에 대 한 오차항을 배제하고 시나리오간 모의 변수의 평균 차이항만을 고려하여 화산재 확산 해석 결과만을 이용해 앙상블을 수행했으며 단순 모형 평균(SMA; Simple Model Averaging) 방법과 비교하여 불확실성이 감소하는 것을 확인할 수 있었다.

The purpose of this study is to present the basic data of species composition and characteristics of agricultural ecosystem by surveying and analysing the flora distributed in farmland, Daegu Metropolitan City. The numbers of flora were summarized as 207 taxa including 52 families, 157 genera, 188 species, 17 varieties and 2 forms. Among the cultivated plants, Cryptotaenia japonica, Pimpinella brachycarpa, Petasites japonicus and so forth were wild. The naturalized plants were 44 taxa including Fallopia dumetorum, Chenopodium album, Thlaspi arvense, Verbesina alternifolia, Festuca myuros and so forth. Plants that expected to spread nationwide were 11 taxa including Amaranthus patulus, Lepidium virginicum, Xanthium canadense, Bromus unioloides and so forth. The NI and UI were about 21.3% and 13.7%. The invasive alien plants were 3 taxa including Ambrosia artemisiifolia, Aster pilosus and Lactuca scariola. The C4 plant were 21 taxa including Commelina communis, Cymbopogon tortilis var. goeringii, Imperata cylindrica var. koenigii, Cyperus amruicus and so forth.

PURPOSES : The purpose of this study is to investigate the stresses of the middle slab in a double-deck tunnel owing to the slab lift to replace the underlying elastic pads during maintenance workMETHODS: The middle slab was divided into three different sections: typical section, expansion joint section, and emergency passageway section. Finite element analysis models of these three sections of middle slab were developed, and the stress distribution and maximum stresses were obtained using the models when the middle slab was lifted to replace the underlying elastic pads. Various slab lifting methods were examined in this study such as one-, two-, and multiple-point lifts, distributed lifts, and one or both slab side edge lifts.RESULTS: When the slab side edge is lifted, the longitudinal stresses of the slab are almost the same as the principal stresses. This implies that the governing stresses are the longitudinal stresses. The maximum stresses with both-edge lifts are generally smaller than those with one-edge lifts at all three sections of middle slab.CONCLUSIONS: If the middle slab in a double-deck tunnel is lifted for maintenance, the slab should be lifted at multiple points along the longitudinal direction to reduce the tensile stresses.

This study investigated in the vascular plants of high value ecological conservation Unjangsan (Mt.), Jeollabuk-do, Korea. The numbers of vascular plants were summarized as 604 taxa including 107 families, 343 genera, 530 species, 5 subspecies, 58 varieties and 11 forms. The rare plants were 12 taxa including Paeonia japonica (VU), Syringa patula var. kamibayshii (LC), Cynanchum inamoenum (VU), Schpolia japonica (LC), Scrophularia koraiensis (DD) and so on. The Korean endemic plants were 16 taxa including Pseudostellaria coreana, Clematis trichotoma, Stewartia pseudocamellia, Ajuga spectabilis, Cirsium setidens and so on. In the specific plants by floristic region were 60 taxa, a degree I were 29 taxa (Sisymbrium leteum, Ilex macropoda, Eleutherococcus sessiliflorus, Cirsium pendulum, Veratrum versicolor and so on), 21 taxa of a degree II (Morus cathayana, Phellodendron amurense, Euonymus pauciflorus, Angelica tenuissima, Heloniopsis koreana and so on), 8 taxa of a degree III (Rhynchosia acuminatifolia, Stewartia pseudocamellia, Cynanchum inamoenum, Schpolia japonica, Scrophularia koraiensis and so on), Wisteria floribunda (Planted) of a degree IV and Prunus yedoensis (Planted) of a degree V. The naturalized plants were 42 taxa including Phytolacca americana, Solanum carolinense, Ambrosia artemisiifolia, Aster pilosus, Poa pratensis and so on. Naturalization rate (NR) was 6.9% of all 604 taxa of vascular plants and the invasive alien plants were 3 taxa including Solanum carolinense, Ambrosia artemisiifolia, Aster pilosus. This study is to identify the main plant distribution and protecting valuable plant populations Unjangsan areas in Jeollabuk-do is located in the inland performing will want to take as the basis for designating an ecological and landscape conservation areas.

목적: 6~24세에 해당하는 연구대상자에서 세대에 따른 근시의 분포변화와 진행 정도를 비교하고자 하였다. 방법: 1987년부터 2012년 10월까지 청주와 천안소재의 안경원에 굴절이상 교정을 위해 방문한 사람 64,292명(남성 15,567명, 여성 48,725명)의 굴절검사 데이터를 수집하여 분석하였다. 근시 진행률 비교를 위해 연구대상자의 안경원 방문횟수를 고려하여 단위 기간 당 근시 진행 정도를 파워벡터 방법에 의한 MOD(magnitude of difference)와 VDD(vector difference in diopter)값을 이용하였다. 결과: 6~24세 이르는 연구대상자를 학제에 따라 5개 그룹으로 나누고 5년 간격으로 구분하여 평균 굴절 이상 정도를 비교하였을 때 6~7세를 제외한 모든 그룹에서 (-)방향으로의 유의한 차이를 나타냈다. 방문연 도에 따른 경도, 중등도, 고도 근시의 분포에서는 경도근시의 감소와 중등도 및 고도근시의 증가로 유의한 차이가 있었다. 이러한 추세의 차이는 6~7세 그룹을 제외한 모든 연령그룹에서 동일하게 나타났다. 안경원 에 연속 방문한 경우를 이용해 파워벡터로 환산한 근시 진행 정도는 8~13세 그룹과 14~16세 그룹에서 방문 연도에 따라 유의한 차이를 보였다(p=0.000, p=0.006). 방문 연도에 따른 근시 진행 정도는 전체 대상자에 서 –0.344 D로 나타났고(p=0.000), 특히 6~15세의 경우는 –0.524 D로 더욱 높게 나타났다(p=0.000). 결론: 동일 연령그룹에서 방문 연도가 최근에 가까워짐에 따라 평균 굴절이상 정도가 (-)방향으로 변화 되며, 고도근시의 비율이 높게 나타났다. 또한 과거에 비해 최근에 가까울수록 근시 진행 정도가 더 크게 나 타났다.

The purpose of this study was to characterize the concentration of and evaluate the pollution level of indoor air pollutants among the public-use facilities located in Seoul that are mainly used by medically sensitive users. The data used in this study were analyzed based on the supervision data provided by Seoul Metropolitan Government Research Institute of Public Health and the Environment. There were 399 nursery schools, 188 medical facilities, 42 elderly care facilities and 96 postnatal care centers. The indoor air pollutants to be investigated were analyzed for PM10, CO2, HCHO, TAB and CO. Through the analysis, it was found that among the surveyed pollutants, TAB levels exceeded the criteria most often, in 54 facilities. Among the surveyed facilities, nursery schools exceeded the criteria most often, in 49 facilities. There was a statistically significant difference between the pollutants in each facility (p<05). However, considering the characteristics of the data used in this study, additional factors should be investigated for factors affecting the concentration of each indoor air pollutant for a more rational evaluation.

This study aims to analyze the effects of 4 directions of wind, wind speed, year of construction of slate roofs, installation area and other factors on the concentration and size distribution of airborne fiber particles in farmhouses with a slate roof containing asbestos. Airborne fiber particle samples were collected from the air in six houses with a slate roof containing asbestos using a high flow rate pump (10 L/min) for 2 hours, three times a day with a different condition, 72 times in total. The airborne fiber particle concentrations were measured using a phase contrast microscope, and the size of fiber particles of 72 samples in total was estimated using the mean value of those in each sample measured at 100 with a field of view. The total average concentration of fiber particles collected from in the air in four directions of the targeted farmhouses was 2.83 fiber/L, and its maximum concentration was 5.75 fiber/L, which means that among all samples there was no place that exceeded 10 fiber/L, a recommended indoor air quality standard. The average size of the fiber particles was 11.55 μm, and the maximum size was 40 μm. A multiple regression analysis of factors affecting the concentration and size of fiber particles in the air collected from the farmhouses with a slate roof containing asbestos found that the closer to the main wind direction (p<0.001) and the faster the average wind speed (p<0.05), the fiber particles concentration became significantly higher. In this case, the coefficient of determination was 52.8%. It was also found that the wider the total area of the slate roof (p<0.001) and the slower the average wind speed (p<0.05), the longer the fiber particles; the coefficient of determination for this finding was 19.6%. The concentration of fiber particles in the air of farmhouses with a slate roof appeared to be the highest under the main wind direction, and became significantly higher as the wind speed became faster. This proved that fiber particles were leaked from the slate roof. The size of the fiber particles became significantly longer as the area of the slate roof became wider and the wind speed became slower.

Distribution and composition of the seabed litters in the exclusive economic zone of the West Sea of South Korea including 18 sea-blocks were investigated using a bottom trawl gear of the R/V Tamgtu 20 (National Institute of Fisheries Science) from 24th April 2011 to 4th May 2012. Each trawl shot was conducted for an hour in each sea-block and the total trawl shots was 18. As a result, 325.6 kg of seabed litter in total has been collected.　The quantity of the seabed litter was highest at No. 202 of the sea-block, close to the Heuksan-Do. The highest occupied sea material was plastic (83.1% of entire seabed litters), the second highest material was metal combined with plastic (10.6%), and glass (2.9%), metals (2.3%), vinyl (0.6%), cloth (0.4%) and wood (0.2%) in order. The origin of seabed litters was from fishing gear (89.0% of all seabed litters). Therefore, it could be assumed that most seabed litters were derived from the fishing activity for example fishing nets and ropes.

The objective of this study was to prove possible effects of a habitable place for fish around semi-submersible drilling rig which measured underwater radiated noise, irradiance distribution of rig's light and conducted experimental fishing in Malaysia territory and observed for distribution of fishes around the rig by ROV during drilling operation in the East Sea of Korea. As a result underwater radiated noise was 130 dB/μPa from 156.25 to 187.50 Hz, irradiance distribution of light was between 21.5 and 43.1 lx. Despite this result, underwater radiated noise was not a threat to fish around rig and low irradiance distribution of light also played a role in the luring influence of the fishes at night. Fish showed up in the beginning of drilling operation and at the end of drilling operation. However, there are few fish in the midst of drilling operation. The main reason for this result was the destruction of the habitable place due to blow out mud and broken pieces of ground formation in drilling hole. The results are expected to contribute to reasonable fishery management around rig.

Numerical analysis has been performed to investigate the stress distribution characteristics of auxiliary axle system in a compact special vehicle. Structural and running stability of compact special vehicle is largely affected by auxiliary axle system installation. Structural characteristics of stress and deformation distributions with safe factor in the auxiliary axle system are analyzed. It can be seen that maximum stress happens near the local axle position, and deformation is also predicted. Simulation results are also compared with experimental test data. These results from this study could be applicable for optimal design of diverse axle systems in the compact special vehicle.

PURPOSES: This study aims to develop a rational procedure for estimating the pavement roughness index considering vehicle wandering. METHODS: The location analysis of the passing vehicle in the lane was performed by approximately 1.2 million vehicles for verification of the wandering distribution. According to verification result, the distribution follows the normal distribution pattern. The probability density function was estimated using each lane's wandering distribution model. Then the procedure for applying a weighted value into the lane profile was conducted using this function. RESULTS : The modified index, MRIw, with consideration towards applying the wandering weighted value application was computed then compared with MRI. It was found that the Coefficient of Variation for distribution of lateral roughness index in the lane was high in the case of a large difference between each index (i.e., MRIw and MRI) observed. CONCLUSIONS : This result confirms that the new procedure with consideration of the weight factor can successfully improve the lane representative characteristics of the roughness index.

대형저서동물은 갯벌에서 우점을 차지하고 있으며, 저서환경을 유지하고 환경을 정화하는데 중 요한 역할을 담당하고 있다. 퇴적환경에서 유기물 함량은 저서동물의 서식, 먹이행동, 생존 등 에 영향을 미치게 된다. 본 연구에서는 무안만 초입의 목포연안 인근갯벌(목포지역과 압해지 역)에서 유기물 함량과 저서동물 분포 특성에 대해서 조사하였다. 목포지역은 압해지역에 비해 높은 유기물 함량을 보였으며, 오염지표종인 Musculista senhousia가 우점을 차지하였다. 무안만 초입 인근 갯벌에서 대형저서동물의 분포는 퇴적층 유기물 함량과 유의적 상관관계를 나타내며 두 지역으로 나누어졌다.