• Journal of Korean Society for Geospatial Information Science
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• v.24 no.4
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• pp.75-81
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• 2016

This study focused on exploring real transaction price of apartment and spatial and temporal heterogeneity of the variables that influence real transaction price of apartment from the spatial and temporal perspective. As independent variables that are considered to influence real transaction price of apartment, transport, local characteristics, educational conditions, population, and economic characteristics were taken into account. Accordingly, the influence of independent variables and spatial distribution pattern were analyzed from the global and local aspects. The spatial and temporal changing patterns of real transaction price of apartment which is a dependent variable were analyzed. First, to establish an analysis model, OLS analysis and GWR analysis were conducted, and thereby more efficient and proper model was selected. Secondly, to find spatial and temporal heterogeneity of independent variables with the use of the selected GWR model, Local $R^2$ was used for local analysis. Thirdly, to look into spatial distribution of independent variables, kriging analysis was carried out. Therefore, based on the results, it is considered that it is possible to carry out more microscopic housing submarket analysis and lay the foundation for establishing a policy on real property.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.159-169
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• 2012

The purpose of this study was to assess the vulnerability of forest ecosystem to climate change in South Korea using socio-environmental indicators and the results of two vegetation models named as Hydrological and Thermal Analogy Group(HyTAG), and MAPSS-Century 1(MC1). The changing frequency and direction of biome types estimated by HyTAG model was used for quantifying sensitivity and adaptive capacity of forest distribution. Similarly, the variation and changing tendency of net primary production and soil carbon storage estimated by MC1 model was used for quantifying sensitivity and adaptive capacity of forest function. As socio-environmental indicators, many statistical data such as financial autonomy rate and the number of forestry officer was prepared. All indicators were standardized, and then calculated using the vulnerability assessment equation. The period of vulnerability assessment was divided into the past(1971-2000) and the future(2021-2050). To understand what policy has a priority to climate change, distribution maps of each indicators was depicted and the vulnerability results were compared among administrative districts. Evident differences could be found in entire study area. These differences were mostly derived from regionalspecific adaptive capacity. The result and methodology of this study would be helpful for the development of decision-making supporting system and policy making in forest management with respect to climate change.

• Spatial Information Research
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• v.19 no.3
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• pp.63-72
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• 2011

Urban space structure tends to have a significant change in accordance with maintenance of urban infrastructure such as a traffic route. For this reason, quantitative analysis has been needed to establish spatial distribution and location patterns by considering change of both road accessibility and urban infrastructure level, which can have the most pervasive influence in urban development process. Therefore, this paper aims to analyze spatio-temporal urban morphology through considering distribution patterns of road among transportation infrastructures, population, and spatial structure of metropolitan areas, focusing on Seoul where population growth and the size of urban area have been dramatically increased. For this, we firstly developed and constructed time-series GIS database by using satellite images and topographic maps of the last 70 years to analyze variables which affect urban growth and transportation. In particular, we analyzed the transform of the system of the street by Space Syntax which is able to grasp hierarchical spatial structure through visibility of space and spatial cognition in terms of accessibility. What's more, we analyzed and visualized the relationship urban morphology and road according the regions of Seoul through IPA(Importance Performance Analysis). In terms of the integration land-use and transportation, Space Syntax approach is expected to contribute to efficient urban planning through understanding the influence which various transportation phenomena has an effect on urban development patterns.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.144-150
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• 2016

In southwestern East Sea, we investigated the spatio-temporal distribution characteristics of particulate organic carbon (POC) and nitrogen (PON) in September 2011 (summer), January (winter) and May 2012 (spring). Although cold waters known as the origin upwelling in the surface layer of September were not observed, this periods showed high primary productivity because of high concentrations of chlorophyll, low percentage of non-autotrophic particulate fraction among POC calculated by POC/Chl-a ratio (27%) and low POC/PON ratio (6.2), which means active amino acid and protein synthesis, However, May, 2012 showed low primary productivity because of high percentage of non-autotrophic particulate fractions among POC (66%) and high POC/PON ratio (8.1), Although spring bloom and high primary productivity has been reported in the East Sea, high percentage of non-autotrophic particulate fractions in POC, observed in the East sea during the post 2012 spring, is suggested to be due to the increase of phaeo-pigment during post spring bloom. Thus, composition of particulate organic matter may have sensitively changed by marine environmental factors in spite of same season.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.139-148
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• 2008

Many types of sensor data exhibit strong correlation in both space and time. Suppression, both temporal and spatial, provides opportunities for reducing the energy cost of sensor data collection. Unfortunately, existing clustering algorithms are difficult to utilize the spatial or temporal opportunities, because they just organize clusters based on the distribution of sensor nodes or the network topology but not correlation of sensor data. In this paper, we propose a novel clustering algorithm with suppression techniques. To guarantee independent communication among clusters, we allocate multiple channels based on sensor data. Also, we propose a spatio-temporal suppression technique to reduce the network traffic. In order to show the superiority of our clustering algorithm, we compare it with the existing suppression algorithms in terms of the lifetime of the sensor network and the site of data which have been collected in the base-station. As a result, our experimental results show that the size of data was reduced by $4{\sim}40%$, and whole network lifetime was prolonged by $20{\sim}30%$.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.481-492
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• 1999

The observations on the spatio-temporal distribution and seasonal fluctuations of phytoplankton community were carried out in Deukryang Bay of the Korean Southwestern Sea from June 1992 to April 1993. A total of 75 species of phytoplankton belonged to 47 genera was identified. In Deukryang Bay seasonal succession in dominant species; P. alata, G. flaccida, S. costatum, L. danicus and N. longissima in summer, St. palmeriana, Ch. curvisetus and B. paxillifera in autunm, S. costatum, Ch. curvisetus, E. zodiacus and Pn. pungens in winter, and As. glacialis, As. kariana, N. pelagica, Th. nitzschioides and S. costatum in spring, were very marked, that is to say, the communities structure of phytoplankton in Deukryang Bay appeared to be various species composition and it was occupied with diatoms all the year round. Phytoplankton standing crops fluctuated with an annual mean of $1.4{\times}10^5 cells/1 between the lowest value of 2.6{\times}10^3 cells/1 in July and the highest value of 1.0{\times}10^6 cells/1$ by S. costatum in January. Densities of the phytoplankton cell number by the samples of Deukryang Bay ranged from $2.6{\times}10^3cells/1 to 1.2{\times}10^5 cells/1 with the mean value of 3.6{\times}10^4cells/1 in summer, from 6.0{\times}10^3cells/1 to 2.6{\times}10^5 cells/1 with mean of 1.5{\times}10^5 cells/1 in autumn, from 1.3{\times}10^4cells/1 to 1.0{\times}10^6 cells/1 with mean 3.5{times}10^5 cells/1 in winter, and from 4.8{\times}10^3cells/1 to 6.0{\times}10^5 cells/1 with mean of 1.6{\times}10^5 cells/1$ in autumn. That is to say, phytoplankton standing crops was large in low temperature seasons, on the other hand small in high temperature seasons. Chlorophyll $\alpha$ concentration fluctuated between 0.l9 $\mu$g/l and 12.3 $\mu$g/l in March. in Deukryang Bay seasonal flucturation in chi-$\alpha$ concentration was not marked. Especially, chl-$\alpha$ concentration in the water around Deukryang Island located in the middle part of Deukryang Bay showed patchy distributions with a very high concentration. And chl-$\alpha$ concentration was high during a year. Therefore, phytoplankton production in Deukryang Bay could be very high year-round.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.77-93
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• 2000

Field survey on the spatio-temporal distribution of water quality and chlorophyll a concentration, and the environmental factors on the variation of phytoplankton biomass were carried out at the 23 stations for four seasons in the Shiahae, southwestern coast of Korean Peninsula from February to October in 1995. I made an analysis on biological factor as chlorophyll a concentration as well as environmental factors such as water temperature, salinity and nutrients; ammonia, nitrite, nitrate, dissolved inorganic nitrogen, phosphate, N/P ratio, silicate and Si/P ratio. The waters in the Shiahae were not stratified due to the tidal mixing and high velocity of tidal current. And the high productivity in photic layer were supported by high nutrients concentration from freshwater on lands and bottom waters The low depth of transparency in the Shiahae had a bad influence upon primary production and marine biology. In Shiahae had a sufficient nutrients for primary production during a year. Especially dissolved inorganic nitrogen and silicate were high, the other side, phosphate was low. The source of nutrients in summer and silicate supply depend on input of freshwater from lands, the other side, dissolved inorganic nitrogen and phosphate were depend on rather supplied from bottom layer by the mixing and input of seawater from outside than input of freshwater from lands. Phosphate seemed to become a limiting nutrient for the primary production at all area of Shiahae in winter and at the northern parts in other seasons. However, dissolved inorganic nitrogen seemed to do it at the southern parts in other seasons except winter. Silicate didn't become a limiting nutrient for diatoms in Shiahae. Phytoplankton biomass as measured by chlorophyll a concentration was very high all the year round, it was controlled by the combination of the several environmental factors, especially of nitrogen, phosphorus and the physical factors such as light intensity. [Spatio-temporal distribution, Seasonal fluctuation, Nnutrients, Chlorophyll a, Environmental factors, Nutrient source, Limiting Nutrient, Light, Shiahae] .

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.6 s.312
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• pp.57-64
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• 2006

Motion estimation plays an important role for the compression of video signals. The proposed method utilizes an adaptive threshold and characteristics of a distribution of SAD (sum of absolute difference). Generally, the more complex the SAD distribution is, the larger SAD value tends to be. This proposed algorithm tries to reduce the search points in a simple distribution but increase them in a complex distribution to avoid local minima. A macro block is divided into 9 areas. One of them chosen using spatio-temporal correlation is called the primary area and the others are called the secondary area that will be searched to avoid local minima. The proposed algorithm decides if just one area (the primary area or the secondary area) will be enough to be searched or both areas should be searched, using adaptive threshold. Compared with famous motion estimation algorithms, the simulation result shows that the searching points per macro block and MSE decreases about 16.4% and 32.83 respectively on the average.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.335-343
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• 2016

The spatio-temporal distribution of jellyfish in Masan Bay was investigated in this study using a numerical model. First, a three-dimensional hydrodynamic model (POM) was constructed,taking into account residual flows, tides, temperature, salinity, and wind effects. A particle tracking model based on residual flow was then used to investigate the jellyfish present in Masan Port, referred to as the Heavy Industry and Gapo New Port in Masan. Jellyfish distribution was concentrated with maximum (2,533 individual) in the North Sea near Machang Bridge. Itcan be concluded that this concentration was due to multi-directional residual flows and topography effects. Residual flow currents are a dominant factor in understanding the aggregation of jellyfish, and this study used a numerical simulation of tide-induced residual currents, wind-driven currents and density currents in distinct cases to thoroughly address the topic. As a result, wind-driven currents (effect of the wind) was found to be superior to other components as an influence on the distribution of jellyfish near Machang Bridge and Modo in Masan Bay.

• Journal of the Korean association of regional geographers
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• v.22 no.3
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• pp.628-642
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• 2016

In small countries such as Korea, rapid expansion of cities has been pointed out as the main cause of urban and environmental issues. In order to understand the urban problems caused by urban sprawl and prepare countermeasures for it, urban sprawl must be accurately measured first of all. The purpose of this study is to analyze the spatio-temporal changes of urban sprawl process in Seoul Metropolitan Area using landscape indices which measure the degree of urban sprawl in terms of urban structure such as area, distribution, and shape of urbanized area. FRAGSTATS, which is a tool for landscape analysis, is utilized to calculate landscape indices. Major findings are as follows. First, the urban sprawl in Seoul Metropolitan Area has been continually intensified since the late 1980s and this tendency was more clearer in the 1990s than the 2000s. While leapfrog development is relatively prominent in the 1990s, infilling development is remarkable in the 2000s. Second, the progress and development types of sprawl progress were different according to the zones which are defined based on Seoul Metropolitan Area Readjustment Planning Act. Congestion Restrain Zone shows the highest level of urban sprawl in terms of the evaluated landscape indices, but infilling development was predominant. In Growth Management Zone1, leapfrog development was dominant in the 1990s and infilling development in the 2000s. In Growth Management Zone1, leapfrog development has been continually remarkable since the late 1980s. Nature Conservation Zone shows the lowest level of sprawl, but its sprawl tendency is gradually being intensified. Third, the sprawl tendency in Seoul Metropolitan Area was different according to the distance and direction from Seoul. Urban sprawl was remarkable at Si-Guns close to Seoul in the late 1980s, Si-Guns close to Seoul and the southern part of Seoul in the late 1990s, and the southern and northern parts of Seoul in the late 2000s.