• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.351-360
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• 2013

Harmonic analysis enables to characterize patterns of variation in MODIS NDVI time series data and track changes in ground vegetation cover. In harmonic analysis, a periodic phenomenon of time series data is decomposed into the sum of a series of sinusoidal waves and an additive term. Each wave is defined by an amplitude and a phase angle and accounts for the portion of variance of complex curve. In this study, harmonic analysis was explored to tract ground vegetation variation through time for land-cover vegetation change detection. The process also enables to reconstruct observed time series data including various noise components. Harmonic model was tested with simulation data to validate its performance. Then, the suggested change detection method was applied to MODIS NDVI time series data over the study period (2006-2012) for a selected test area located in the northern plateau of Korean peninsula. The results show that the proposed approach is potentially an effective way to understand the pattern of NDVI variation and detect the change for long-term monitoring of land cover.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.18-31
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• 2018

It is important to conduct various analyzes to evacuate occupants in advance, because the disaster can cause serious injury. Therefore, it is necessary to analyze all the predictable scenarios that may occur. In this study, we propose a method to analyze the evacuation of indoor disaster using activity - based transport model MATSim. We have developed the university building as target area and simulated about 5,000 occupants. The analysis scenarios are set as basic evacuation conditions, exit closures and emergency stair closures. As a result of analysis of each scenario, the evacuation time was analyzed to be about 5:40(340s) in the base scenario, increased by 15% in the scenario 2 and increased by 23% in scenario 3. As a result of this study, we suggest that it is important to manage illegal obstacles of emergency stairs for rapid evacuation. Therefore, this study can contribute to the effective disaster prevention strategy of the building.

• Journal of the Korean Geographical Society
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• v.42 no.5
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• pp.788-807
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• 2007

To better publish geographical information on the Web, it is important to capture how Web technologies are changing. For a recent decade, Semantic Web has been developed by incorporating ontologies into the current Web, with an aim to make computers understand rather than simply display. Ontology, an explicit specification of a conceptualization, and the Semantic Web grounded on the ontology, have the potential for effective sharing and appropriate retrieval of geographical information. This paper describes a Semantic Web Service over the mobile Web that can offer pertinent tourism information according to user contexts. To do this, a tourism ontology was formalized in the PARA(Place-Attraction-Resource-Activity) ontology model by organizing tourist places, tourist attractions, tourism resources, and activities. Locational relationships between tourist places were also included in the PARA ontology model to take into account the movements of tourists on a railway network. The XML(Extensible Markup Language) Web Service in the middle tier manages the client-side request for information retrieval and the corresponding server-side response from the data provider. The PARA ontology was integrated into the XML Web Service for the concept-based discovery of tourism information. The applicability of the proposed system was tested through a simulation experiment for Tokyo tourism.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.2
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• pp.23-29
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• 2012

Existing pedestrian and evacuation models generally seek to find locally optimal solutions for the shortest or the least time paths to exits from individual locations considering pedestrian's characteristics (eg. speed, direction, sex, age, weight and size). These models are not designed to produce globally optimal solutions that reduce the total evacuation time of the entire pedestrians in a building when all of them evacuate at the same time. In this study, we suggest a globally optimal model for indoor pedestrian evacuation to minimize the total evacuation time of occupants in a building considering different distributions of them. We used the genetic algorithm, one of meta-heuristic techniques because minimizing the total evacuation time can not be easily solved by polynomial expressions. We found near-optimal evacuation path and time by expressing varying pedestrians distributions using chromosomes and repeatedly filtering solutions. In order to express and experiment our suggested algorithm, we used CA(cellular automata)-based simulator and applied to different indoor distributions and presented the results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.2
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• pp.221-230
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• 1997

In hydrology analysis, the result of a slope analysis for terrain have an very important effect on water quality and water quantity Recently, a slope analysis tend to use the digital elevation model rater than the traditional map sheet. But a terrain slope analysis by the digital elevation model depends on grid size of the digital elevation model. Hence the effect of a slope analysis by the digital elevation model is a important factor. In this study, therefor, in order to determine a hydrological parameter and a terrain parameter for simulation of the water quality and the hydrological property, we adapted two sample area that are the Nerin stream of the basin of the Soyang lake and a Osip stream of Samchuk, and its individual coverages are $640\;km^2$ and $33\;km^2$. Also to analyze the effect of grid size in the slope of a basin, we apply DEM changing a grid size respectively at intervals of 100 m from 100 m to 1.000m for the Nerin stream basin and at intervals of 10 m from 20 m to 300 m for the Osip stream basin.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4B
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• pp.378-385
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• 2011

The three-dimensional triangulation algorithm that the beacon nodes can be allocated to dynamically in not the experimental region but the practical region is suggested, and the performance of the localization system adapting the suggested algorithm is analyzed. The suggested algorithm adapts the computation method of the three dimensional point that the surfaces of three spheres overlapped, while the traditional triangulation algorithm adapts the computation method of the two dimensional point that three circles are overlapped in order to compute the distance between beacon nodes and mobile node that means a radius. In addition to this, to analyze the performance of the localization system adapting the suggested algorithm, first of all, the allocation layout of beacon nodes is made, and the allocation layout is modeled by selection of ten random distance values between mobile node and beacon nodes for computer simulation of the practical model. Next, the two dimensional coordinator of mobile node that is calculated by the suggested algorithm and the traditional triangulation algorithm is compared with each other. The localization measuring performance about three dimensional coordinator(z axis) of the suggested algorithm is also obtained by comparing with that of the practical model.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.53-61
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• 2012

This study developed a growth model for Larix leptolepis based on the WLS model to examine the effects of climate change on them. The site index was chosen as the dependent variable and location, weather, and edaphic factor were chosen as independent variables. Simulations were performed under three A1B climate change scenarios with the temperature ranging from $-3.3^{\circ}C$ to $+3.3^{\circ}C$. The simulation results showed that the site index decreased with peak at $-0.8^{\circ}C$. The decrease level of the site index by region was also analyzed. Each scenario, site index has decreased mostly but some region was increased. When the temperature increased up to $3^{\circ}C$, site index was decreased to everywhere.

• The Korean Journal of Applied Statistics
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• v.28 no.1
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• pp.33-47
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• 2015

We consider an $M/E_n/1$ queueing model where customers arrive at a facility with a single server according to a Poisson process with customer service times assumed to be independent and identically distributed with Erlang distribution. We concentrate on the overshoot of the workload process in the queue. The overshoot means the excess over a threshold at the moment where the workload process exceeds the threshold. The approximation of the distribution of the overshoot was proposed by Bae et al. (2011); however, but the accuracy of the approximation was unsatisfactory. We derive an advanced approximation using the property of the Erlang distribution. Finally the newly proposed approximation is compared with the results of the previous study.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1128-1141
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• 2009

Graphical expressions are continuously improving, spurred by the astonishing growth of the game technology industry. Despite such improvements, users are still demanding a more natural gaming environment and true reflections of human emotions. In real life, people can read a person's moods from facial color and expression. Hence, interactive facial colors in game characters provide a deeper level of reality. In this paper we propose a facial color adaptive technique, which is a combination of an emotional model based on human emotion theory, emotional expression pattern using colors of animation contents, and emotional reaction speed function based on human personality theory, as opposed to past methods that expressed emotion through blood flow, pulse, or skin temperature. Experiments show this of expression of the Facial Color Model based on facial color adoptive technique and expression of the animation contents is effective in conveying character emotions. Moreover, the proposed Facial Color Adaptive Technique can be applied not only to 2D games, but to 3D games as well.

• Journal of Intelligence and Information Systems
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• v.12 no.4
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• pp.91-107
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• 2006

This study introduces a software system for supporting the engineering process of container terminals. The design procedure consists of data input, capacity requirements, alternative design, alternative evaluation, and results output. In order to design and evaluate alternatives rapidly, a set of libraries for container terminals was developed. The libraries consist of Wharf, Yard, TravellingArea, and Gate. The architecture of the set of libraries was designed by an object-oriented approach. Various types of container terminal models can be constructed by using a user friendly interface, the CAD based environment, and the combinations of the elements of the libraries. Alternative models can be evaluated by a simulation.