• Journal of Environmental Impact Assessment
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• 제20권5호
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• pp.705-716
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• 2011

For the efficient discovery of knowledge and information from the observed systems, data mining techniques can be an useful tool for the prediction of water quality at intake station in rivers. Deterioration of water quality can be caused at intake station in dry season due to insufficient flow. This demands additional outflow from dam since some extent of deterioration can be attenuated by dam reservoir operation to control outflow considering predicted water quality. A seasonal occurrence of high ammonia nitrogen ($NH_3$-N) concentrations has hampered chemical treatment processes of a water plant in Geum river. Monthly flow allocation from upstream dam is important for downstream $NH_3$-N control. In this study, prediction models of water quality based on multiple regression (MR), artificial neural network and data mining methods were developed to understand water quality variation and to support dam operations through providing predicted $NH_3$-N concentrations at intake station. The models were calibrated with eight years of monthly data and verified with another two years of independent data. In those models, the $NH_3$-N concentration for next time step is dependent on dam outflow, river water quality such as alkalinity, temperature, and $NH_3$-N of previous time step. The model performances are compared and evaluated by error analysis and statistical characteristics like correlation and determination coefficients between the observed and the predicted water quality. It is expected that these data mining techniques can present more efficient data-driven tools in modelling stage and it is found that those models can be applied well to predict water quality in stream river systems.

• Korean Journal of Remote Sensing
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• 제36권1호
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• pp.67-81
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• 2020

The rapid climatic changes being caused by global warming are resulting in abnormal weather conditions worldwide, which in some regions have increased the frequency of landslides. This study was aimed to analyze and compare the landslide susceptibility using the Frequency Ratio (FR), Statistical Index, Weight of Evidence, Certainty Factor, and Index of Entropy (IoE) at Woomyeon Mountain in South Korea. Through the construction of a landslide inventory map, 164 landslide locations in total were found, of which 50 (30%) were reserved to validate the model after 114 (70%) had been chosen at random for model training. The sixteen landslide conditioning factors related to topography, hydrology, pedology, and forestry factors were considered. The results were evaluated and compared using relative operating characteristic curve and the statistical indexes. From the analysis, it was shown that the FR and IoE models were better than the other models. The FR model, with a prediction rate of 0.805, performed slightly better than the IoE model with a prediction rate of 0.798. These models had the same sensitivity values of 0.940. The IoE model gave a specific value of 0.329 and an accuracy value of 0.710, which outperforms the FR model which gave 0.276 and 0.680, respectively, to predict the spatial landslide in the study area. The generated landslide susceptibility maps can be useful for disaster and land use planning.

• Applied Chemistry for Engineering
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• 제17권3호
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• pp.296-302
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• 2006

The kinetics of the thermal-oxidative decomposition of waste polyurethane (PU) according to oxygen concentration has been studied using a non-isothermal thermogravimetric technique at several heating rates from 10 to $50^{\circ}C/min$. A kinetic model accounting for the effects of the oxygen concentration by the differential and integral method based on Arrhenius equation was proposed to describe the thermal-oxidative decomposition of waste PU. To obtain the information on the kinetic parameters such as activation energy, reaction order, and pre-exponential factor, the thermogravimetric analysis curves and its derivatives have been analyzed using the kinetic analysis method proposed in this work. From this work, it was found that reaction orders for oxygen concentration had a negative sign, and activation energy decreased as the oxygen concentration increased. It was also found that the kinetic parameters obtained from the integral method using the single heating rate experiments varied with heating rates. Therefore, it is thought that the differential method using the multiple heating rate experiments more effectively represents the thermal-oxidative decomposition of waste polyurethane.

• Journal of Internet Computing and Services
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• 제8권2호
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• pp.43-54
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• 2007

The effective power consumption is the primary issue in a sensor network which consists of the sensor nodes with limited battery power. So, most of the MAC protocols in sensor networks have been designed with the consideration of energy efficiency. Generally, these protocols make use of the listen and sleep mode periodically. However, this approach inevitably causes a long transmission delay on the data forwarding path, which is mainly resulted from the sleep time of the receiver node. This paper deals with a design of DT-MAC(Data Transmission centric MAC) protocol, with minimizes the data transmission delay while it forces each node to consume its energy efficiently. Thus, a node received a packet converts its remained sleep time to the pseudo_listen time, in which the node is able to transmit a packet. With benefit of the pseudo_listen period, the data transmission delay along with the data forwarding path will be shortened as much as it possible. Therefore, DT-MAC protocol is very suitable to the various applications which require a real time sensing data such as disaster and fire alarm.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• 제21권2호
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• pp.181-189
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• 2003

A virtual flood scenario has been constructed to investigate the overflowing process in the flooding area. The topography is constructed using the airborne LIDAR data. In addition, the frequency and scale of the flooding and the destruction condition of the flooding defensive structure are used as input to the scenarios. Through the scenario, the inundation depth with respect to time and maximum depth has been analyzed. This analysis shows the water level variation with time which show the flooding process. Moreover, a flooding map is drawn using the results from the scenario, distribution of the defensive structure, vulnerable area, and expected destruction points in the study area. It is expected that this study can be effectively used to examine the flooding process and flood disaster management. Furthermore, it could provide important basic information for the land development and the city planning of a possible flooding area.

• Journal of Korean Society of Archives and Records Management
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• 제4권1호
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• pp.101-116
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• 2004

Deterioration and brittleness of resources on the shelves of institutions such as libraries and archives have been increased and accelerated as time passes in accordance with the preservation environment and the nature of their own material. It can be a loss of current information with little importance in prolong the life of valuable materials and to preserve them in security, integrated preservation programs should be developed and implemented according to missions, sizes, the nature of collections, users, and budgets of individual institutions. In reality, most institutions, however, are not able to implement perfect preservation programs due to lack of budget, human resources, and expertise. To solve this problem, some institutions in similar circumstances have planned cooperative preservation programs in various levels. Through cooperative systems individual institutions can not only pursue common interests but gain real benefits for themselves. Consequently institutions are recommended to collaborate with in development and implementation of various preservation programs at local, national, and international levels in addition to individual institutional programs.

• Fire Science and Engineering
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• 제24권4호
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• pp.98-103
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• 2010

The design disaster prevention of first consideration is security for the people in the buildings. However, it is difficult to make a project for considering variable cases, declined visibility of smoke, distance from another person, mentality, knowledge of clearway etc. This study purpose is, analysis variable cases and modularization of pattern movement to practice basic information for evacuation of simulation which is used RTLS (Real Time Location System) system. It is useful to sense the electric waves from the Tag and grasp the real-time position. The pattern movement of evacuation were analyzed prescription eyeglasses which is used RTLS system to consider following 3 actions; analysis of relations that declined visibility effect the decline of movement velocity, analysis rate of flow with the size of door to estimate the optimum size of door in building and analysis the pattern movement that a bottleneck situation with abundant of people passed together to these exit. The confirmed of propriety of the interpretation about the actual people to evacuate is expected applying the numerical formula in various situation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.91-96
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• 2012

Ad-hoc networks can be used various environment, which it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio (CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. In CR based wireless ad-hoc networks, cluster-head decides the existence of primary user using sensing information of primary user from each ad-hoc device. However, it is still defective research to decide cluster head among the a lot of ad-hoc devices. So, in this paper, we show the decision method of cluster head in CR based wireless and detection probabilities of primary user based on decision method of cluster head.

• Journal of the Korean GEO-environmental Society
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• 제11권3호
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• pp.63-68
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• 2010

The purpose of this paper is estimating of the amount of debris flow in hazard area using terrestrial LiDAR surveying data. Jecheon area was selected for this study. Then, the surveyed LiDAR information of DEM and 1:5000 digital map of DEM have been compared with each other and the amount of debris flow has been estimated. The result of this study was shown that the amount of erosion was $24,150m^3$ and deposition was $14,296m^3$. Well shape of channelized debris flow, hillslope debris and deposition at the bending reach of a channel can be found in the area. This study on estimation of the amount of debris flow was expected to provide more informations for debris flow of disaster mitigation and simulation work.

• Journal of the Korean Institute of Intelligent Systems
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• 제27권2호
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• pp.164-169
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• 2017

The primary purpose of this study is to determine NDVI analysis methodologies for green algae monitoring system. A fixed wing UAV integrated with multi-spectral sensor has been adopted to capture the images along the watershed in Gumgang River. The study area was near the Baekje water reservoir and the images was captured on July 2016. Pix4D Mapper Pro was used to process the captured images. Through the comparison actual chlorophyll measurement values with NDVI output image, empirical formula was suggested and geo-locational conversion was carried out. As a result of this study chlorophyll image set applied to actual measurement values was able to extracted. For the efficient management of green algae, its monitoring and prevention in terms of disaster management, gathering chlorophyll information using UAV is very beneficial.