• 한국지리정보학회지
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• 제10권4호
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• pp.60-74
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• 2007

해양환경의 시공간적 분포 패턴을 정량적으로 분석하기 위해 남해 광양만 해양환경 관측 자료를 이용하여 글로벌 및 국지적 공간자기상관 통계를 적용하였다. 연구지역 전체의 해양환경 분포 패턴을 이해하기 위해 Moran's I, General G와 같은 글로벌 공간자기상관 지수를 사용하였으며, 대상 피쳐(feature)와 이웃 피쳐들과의 유사성 정도를 측정하고 hot spot 및 cold spot을 탐지하기 위해 국지적 Moran's I ($I_i$), $G_i{^*}$와 같은 LISA(local indicators of spatial association)를 사용하였고, 공간 군집 패턴의 신뢰성은 Z-score를 통한 통계적 유의성 검증을 수행하였다. 공간 통계 결과를 통해 년 중 해양환경 공간분포 패턴의 변화를 정량적으로 알 수 있었는데, 일반 해양수질, 영양염, 클로로필 및 식물플랑크톤은 여름철에 강한 군집 패턴을 보였다. 글로벌 지수에서 강한 군집 패턴을 보였을 때 속성 값의 공간적인 변화가 심한 음적 $I_i$ 값을 가지는 전선지역이 탐지되었다. 또한, 글로벌 지수에서 임의적 패턴을 보였을 때 국지적 지수인 $G_i{^*}$에서는 좁은 지역에서 hot spot과(또는) cold spot이 탐지되었다. 따라서 글로벌 지수는 연구 지역 전체 군집 패턴의 강도와 시계열적 변화 과정 탐지에, 국지적 지수를 통해서는 hot spot과 cold spot 위치 추적에 유용함을 알 수 있었다. 해양환경 공간분포 패턴과 군집 특성을 정량화는 것은 해양환경을 보다 깊이 이해할 수 있도록 할 뿐 아니라, 패턴의 원인을 찾는데도 중요한 역할을 할 것이다.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E3호
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• pp.95-105
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• 2005

The concentrations of sulfur dioxide ($SO_{2}$) were measured from seven major cities and nine provinces in Korea for the period covering 1998 to 2003. Its concentration data were analyzed to explore the possible influences of spatial and temporal factors on the $SO_{2}$ distribution characteristics. Examination of spatial trends of $SO_{2}$ distribution and behavior indicated several interesting features. Although its annual trends appeared to be affected by the changes in the surrounding environmental conditions (e.g., regulation on the use of S-containing fuels), the seasonal trends indicated a cyclic and systematic pattern that may be characterized as: a gradual decrease in concentrations across winter, spring, fall, and summer. The results showed the generally enhanced mean concentrations of $SO_{2}$ from Ulsan, Busan, and Daegu with 12.8, 10.1, and 8.80 ppb, respectively. On the other hand, notably reduced $SO_{2}$ concentrations were seen from Gwangju and Jeju sites with its mean values of 5.43 and 3.88 ppb, respectively. The overall results of our study indicate that a decrease in $SO_{2}$ concentration levels continued through time, while its spatial distribution appears to be affected most sensitively by such factor as city scale and industrial activities.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.73-76
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• 2001

We have simulated the effect of fracture characteristics on reduction of effective permeability of the fractured rocks due to in-situ bacteria growth. A nutrient is injected continuously for growth of in-situ bacteria. We used a power law for fracture length distribution and a fBm for fracture aperture spatial distribution. The results show that in-situ bacteria growth reduces the Permeability hyperbolically, but the porosity of backbone fracture does not change significantly. It shows that reduction of the permeability proceeds at faster speed for smaller value of length exponent(a) and for larger value of Hurst exponent(H). The fracture length distribution has stronger effect on speed of reduction than the aperture spatial distribution. The time needed to reduce permeability is inversely proportional to the hydraulic gradient.

• 한국환경과학회지
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• 제20권1호
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• pp.107-118
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• 2011

While the assessment of mean flow field is very important to characterize the hydrodynamic aspect of the flow regime in river, the conventional methodologies have required very time-consuming efforts and cost to obtain the mean flow field. The paper provides an efficient technique to quickly assess mean flow field by developing and applying spatial averaging method utilizing repeatedly surveyed acoustic Doppler current profiler(ADCP)'s cross-sectional measurements. ADCP has been widely used in measuring the detailed velocity and discharge in the last two decades. In order to validate the proposed spatial averaging method, the averaged velocity filed using the spatial averaging was compared with the bench-mark data computed by the time-averaging of the consistent fix-point ADCP measurement, which has been known as a valid but a bit inefficient way to obtain mean velocity field. The comparison showed a good agreement between two methods, which indicates that the spatial averaging method is able to be used as a surrogate way to assess the mean flow field. Bed shear stress distribution, which is a derived hydrodynamic quantity from the mean velocity field, was additionally computed by using both spatial and time-averaging methods, and they were compared each other so as to validate the spatial averaging method. This comparison also gave a good agreement. Therefore, such comparisons proved the validity of the spatial averaging to quickly assess mean flow field. The mean velocity field and its derived riverine quantities can be actively used for characterizing the flow dynamics as well as potentially applicable for validating numerical simulations.

• 한국소음진동공학회논문집
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• 제18권1호
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• pp.20-25
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• 2008

음향홀로그래피는 시간 영역 혹은 주파수 영역에서 음압의 공간 분포를 가시화하는 방법이다. 그러나, 재구성된 음압은 종종 실제적으로 우리가 원하는 음장의 정보보다 훨씬 많은 정보를 가지고 있다. 예를 들어, 우리가 소음 제어를 위해 필요로 하는 정보는 소음원의 위치와 전체적인 방사형태의 정보만으로 충분하다. 따라서, 이렇게 필요로 하는 정보만을 보여줄 수 있는 방법이 필요하다 볼 수 있다. 이를 위한 한 가지 방법으로 공간에서의 포락을 생각할 수 있다. 공간복소포락은 소음원의 위치와 느리게 변하는 전체적인 변화에 대한 정보를 가지고 있는 포락 신호를 의미한다. 공간복소포락을 이용함으로써, 우리는 음장에서 불필요한 정보를 제거하여 필요한 정보를 얻을 수 있을 뿐만 아니라, 가시화 과정에서의 연산 시간도 줄일 수 있다. 이 공간포락을 얻기 위한 공간변조 방법을 이론적으로 유도하고 제안한다. 그리고, 여러 개의 단극음원에 의해 형성되는 복잡한 음장을 제안하는 방법을 이용해 단순화시킨 결과를 통해 제안하는 방법에 대한 타당성을 검증한다.

• Asian-Australasian Journal of Animal Sciences
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• 제9권5호
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• pp.603-610
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• 1996

Spatial distribution of faeces by Japanese Black heifers and steers was investigated. The animals grazed a bahiagrass (Paspalum notatum $Fl\ddot{u}gge$) pasture in the daytime from 9 a.m. to 4 p.m., and spent the rest of the day in a barn. The pasture consisted of three paddocks, an alley and a resting area, and the paddocks were grazed rotationally. The number of defecations and the faecal weight excreted in the pasture were greater than those expected from the proportion of time that the animals spent in the pasture. These values were correspondingly smaller in the barn. The distribution of faeces to the paddock, alley and resting area of the pasture was usually not proportional to the area of the respective places. The number of defeations and the faecal weight were usually distributed less densely in the paddock than in the resting area. The degree of aggregation of defecation in the paddock, alley and resting area varied with the meteorological factors such as the air temperature, solar radiation and rainfall during the grazing, and the intake of hay supplement of the previous day.

• The Korean Journal of Ecology
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• 제16권3호
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• pp.305-316
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• 1993

Stands profiles, yearly changes in growth of annual rings, age and diameter structure, and spatial distribution pattern of individuals in the Pinus densiflora stands around the Yeocheon industrial complex were investigated. Growth of annual ring in Pinus densiflora, which survived when vegetation of this area was damaged by air pollutants, was suppressed for about 10 years since 1974 when factories in this area began to operate, but since then such suppressed growth tended to be recovered. It was supposed that the suppresed growth was originated from air pollution and that improvement of growth since the suppressed period was due to the release from competition with them by death of neighbouring trees and the resuction of the amount of air pollutants. Physiognomy of Pinus densiflora stands showed mosaic pattern composed of different patches. Spatial distribution pattern of individuals an stand profiles were similar to those of Pinus densiflora stands regenerated after natural and artificial disturbances. In an age distribution diagram, age of Pinus densiflora population ranged from 1 to 33 years, Among these individuals were recrited corresponded to the suppresed period of growth of annual ring in Pinus densiflora survived when the vegetation was damaged by air pollution. On the other hand, from the result of analysis of frequency distribution diagram of diameter, it was postulated that even if whis Pinus densiflora community can be maintained as it is for the time being, it might be changed to Quercus community with the lapse of time.

• Computers and Concrete
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• 제32권3호
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• pp.247-261
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• 2023

Due to the non-uniform distribution of meso-structure, the diffusion of chloride ions in concrete show the characteristics of characteristics of randomness and fuzziness, which leads to the non-uniform distribution of chloride ions and the non-uniform corrosion of steel rebar in concrete. This phenomenon is supposed as the main reason causing the uncertainty of the bearing capacity deterioration of reinforced concrete structures. In order to analyze and predict the durability of reinforced concrete structures under chloride environment, the random features of chloride ions transport in concrete were studied in this research from in situ meso-structure of concrete. Based on X-ray CT technology, the spatial distribution of coarse aggregates and pores were recognized and extracted from a cylinder concrete specimen. In considering the influence of ITZ, the in situ mesostructure of concrete specimen was reconstructed to conduct a numerical simulation on the diffusion of chloride ions in concrete, which was verified through electronic microprobe technology. Then a stochastic study was performed to investigate the distribution of chloride ions concentration in space and time. The research indicates that the influence of coarse aggregate on chloride ions diffusion is the synthetic action of tortuosity and ITZ effect. The spatial distribution of coarse aggregates and pores is the main reason leading to the non-uniform distribution of chloride ions both in spatial and time scale. The chloride ions concentration under a certain time and the time under a certain concentration both satisfy the Lognormal distribution, which are accepted by Kolmogorov-Smirnov test and Chi-square test. This research provides an efficient method for obtain mass stochastic data from limited but representative samples, which lays a solid foundation for the investigation on the service properties of reinforced concrete structures.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.61-64
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• 2005

The purpose of this paper is to take a closer look at an area having shorted emergence facilities and to determine optional candidate sites instead of vulnerable area by using GIS spatial analysis. Newly determined new candidate is performed by concerning spatial efficiency and spatial equity for a public service. It was determined through using the analyzing of the physical accessibility measure, the Location-Allocation, sort of classic model in spatial statistics and general network analysis. The area of this research has been used in administrative boundary of Young-Dong in Gangneung including 13 emergency, medical hospitals, 46 fire-stations and sub-fire stations. In general terms, what all this show is that the way we are approached for geographical view from using GIS spatial analyzing technique of determined location and allocation problem by the social, economical, political factor and simple administrative discrimination at the meantime. At the same time, with problem occurred in the space it is possible to make an Effective proposal or means, policy, decision for new candidate location-allocation suggesting optimum model.

• 환경생물
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• 제23권2호
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• pp.93-97
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• 2005

Zooplankton dynamics were investigated based on samples collected monthly during the period between November 1998 and October 1999 at 15 stations in Gwangyang and Sachon Bay. Zooplankters were quantitatively collected with horizontal towing through the surface and oblique hauling from the bottom to surface at each station, simultaneously. A total of 88 taxa of zooplankton were distributed and 60 taxa were identified to species. Copepods showed the prosperity in species number of 52 species. Number of taxa occurred in samples hauled obliquely always showed $2\~5$ more species than those captured in the surface except for stations near the Namhae bridge. In waters near Namhae bridge, fast current seemed to mix waters vertically. Seasonally these differences were more distinct in the spring and summer than those in other seasons possibly due to the stratification in warmer seasons. In quantitative aspects, differences between two layers seemed to be obscure. Spatial and temporal variations in species diversity of copepods showed more prosperity in pelagic realm than those in the surface. Our collection carrying out in day time might be one of the important reason to cause these differences in zooplankton dynamics between two layers.