• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.766-769
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• 2005

본 연구에서는 카오스 랜덤 캐리어 PWM에 의한 3상 유도 전동기의 스위칭 소음 저감에 대하여 다루고 있다. 랜덤 수 발생기로서는 종전부터 사용해 온 선형일치발생기(LCG)대신에 Logistic map의 분기트리를 사용하였다. 카오스 랜덤 수 발생은 80C196 마이크로 콘트롤러가 담당하고 있으며, 80C196으로부터 발생된 카오스 랜덤 수와 MAX038에 의하여 삼각파 랜덤 캐리어가 발생되고 있다. 1.5kw급 3상 유도전동기 구동 시스템에 카오스 랜덤 PWM와 종전의 방법을 적용하여 전동기 전압 및 전류 그리고 스위칭 소음의 스펙트럼을 고찰하였다.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.9
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• pp.101-108
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• 2019

Chinese ethnic minorities are inheriting their own traditions based on thousands of years of community life. Yunnan province in china is a castle in which many ethnic minorities have been living on the basis of various natural environments. Their traditional village can be regarded as a place reflecting minorities' thousands year of history and culture, and elements of positive social spaces are seen from the old village. Streets and places of the village are accumulated as images for residents. Based on their imagination-concept, sketch maps, reflecting residents' cognitive perception were collected. Analysis of 21 sketch maps shows that architectural elements, forming a unique landscape and community life contribute to establish a unity of one nation. the oldest tree in the village has a strong specificity as a place with the belief that the tree protects all residents in the village. Space in the head of the residents and Social spaces, embedded in the memories of the residents living in the community continued organically and the roads of the village showed clear recognition. Following this, the analysis methodology of social spaces and sketch will be examined in depth.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.35-47
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• 2018

Tree height is information that is used as a parameter for variety of tasks related to forests. Specifically, customized topics related to forests such as afforestation map are also used for production. In order to calculate tree height information, a field survey or drawing was using aerial photographs. However, there is a problem that is costing a lot of time and money. Therefore, it was suggested to calculate tree height using aerial photographs taken every two years. Thus, the method for calculating tree heights was validated by unmanned aerial photogrammetry, and tree heights were calculated using outputs generated by unmanned aerial photogrammetry applied to the unmanned aerial photograph and Aerial photograph DB. The comparison of calculated tree heights shows that the measures proposed in this study are efficient. and We expect to improve the usability of aerial photographs DB.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1721-1730
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• 2023

As awareness of the problem of global warming emerges around the world, the role of carbon sinks in settlement is increasingly emphasized to achieve carbon neutrality in urban areas. In order to manage carbon sinks in settlement, it is necessary to identify the current status of carbon sinks. Identifying the status of carbon sinks requires a lot of manpower and time and a corresponding budget. Therefore, in this study, a map predicting the location of trees was created using already established tree location information and Sentinel-2 satellite images targeting Seoul. To this end, after constructing a tree presence/absence dataset, structured data was generated using 16 types of vegetation indices information constructed from satellite images. After learning this by applying the Extreme Gradient Boosting (XGBoost) model, a tree prediction map was created. Afterward, the correlation between independent and dependent variables was investigated in model learning using the Shapely value of Shapley Additive exPlanations(SHAP). A comparative analysis was performed between maps produced for local parts of Seoul and sub-categorized land cover maps. In the case of the tree prediction model produced in this study, it was confirmed that even hard-to-detect street trees around the main street were predicted as trees.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.589-590
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• 2010

Recently, as various smart phones released smart phones are becoming popular.Accordingly, the growing interest in mobile information service or advertising serviece, and attention has been concentrated in the mobile environment. These servieces should be carried out smoothly in the all situation (cannot access mobile Wi-Fi networks and 3G services), and should have the uniqueness that is fit for purpose. In this papaer, module for a particular purpose of the foundation of specialized location-based map services was implemented using a Packing R-tree by using a GIS engine based on Microsoft Window Mobile and Android operating system without communication device like 3G or Wi-Fi.

• Korean Journal of Computational Design and Engineering
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• v.15 no.6
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• pp.460-466
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• 2010

These days, it is getting important to have more chances to visit natural environment for the wellbeing life. The advancement of digital technologies allows us to get useful information regardless of time and location. In this paper, we investigate a way of improving user experience in the natural green environment using the digital technologies. This paper proposes a system called Green-UX-Story which supports users to create and share their story through the online and offline green experience. The system consists of two main systems: the "Story-Field" and the "Story-Tree". The Story-Field consists of a certain number of the Story-Trees allocated to a certain green site. In the Story-Field, users can see the Story-Trees that are owned by other users and share their stories. The Story-Tree contains the user-story in each branch and green information that are captured by the user on the web. The Story-Tree is generated using the L-system algorithm as the user adds stories. The main purpose of the system is to enable users to write their green stories from the both online and offline experiences. This paper describes the system configuration and the user scenario of the Green-UX-story.

• Current Research on Agriculture and Life Sciences
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• v.26
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• pp.45-54
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• 2008

The purpose of this research is to develope street trees management program for more an effective street trees management. The principal point of this program is to relate spatial data and attribute data that is the main concept in GIS(Geographic Information System). To do this function, MapObjects which is ESRI's mapping and GIS components was used to process spatial data and Access which had been developed by MS was used to manipulate attribute data in this program. Visual Basic also was used to design and develop user interfaces and procedures, relate two sort of data, and lastly complete Application. Relational data model was adopted to design tables and their relation, Antenucci's GIS development model was selected to design and complete this program. The configuration of this application is composed of management data and reference data. The management data includes the location of street tree, a growth condition, a surrounding environment, the characters of tree, an equipments, a management records and etc. The reference data include general information about tree, blight and insects.

• Geomechanics and Engineering
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• v.36 no.5
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• pp.441-453
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• 2024

Sinkhole subsidence and collapse is a common geohazard often formed in karst areas such as the state of Florida, United States of America. To predict the sinkhole occurrence, we need to understand the formation mechanism of sinkhole and its karst hydrogeology. For this purpose, investigating the factors affecting sinkholes is an essential and important step. The main objectives of the presenting study are (1) the development of a machine learning (ML)-based model, namely C5.0 decision tree (C5.0 DT), for the prediction of sinkhole susceptibility, which accounts for sinkhole/subsidence inventory and sinkhole contributing factors (e.g., geological/hydrogeological) and (2) the construction of a regional-scale sinkhole susceptibility map. The study area is east central Florida (ECF) where a cover-collapse type is commonly reported. The C5.0 DT algorithm was used to account for twelve (12) identified hydrogeological factors. In this study, a total of 1,113 sinkholes in ECF were identified and the dataset was then randomly divided into 70% and 30% subsets for training and testing, respectively. The performance of the sinkhole susceptibility model was evaluated using a receiver operating characteristic (ROC) curve, particularly the area under the curve (AUC). The C5.0 model showed a high prediction accuracy of 83.52%. It is concluded that a decision tree is a promising tool and classifier for spatial prediction of karst sinkholes and subsidence in the ECF area.

• Journal of Environmental Science International
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• v.17 no.6
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• pp.647-655
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• 2008

The purpose of the study is to find the problems related to the current state of the stand age classes and the method of calculating it defined in the existing forest type map and propose the more accurate method of calculating the stand age classes. The object for the study was selected as the forest scattered around the Geesan village Paju city in Kyunggi province. For the accurate method of calculating the stand age classes, such items as, the type of actual vegetation, establishment of grid-type standard area scaled down at the level of the 5% of the actual area, the types, number, DBH and age of tree found by the plots, were investigated. It was found out actual vegetation was divided into the total 24 types and the 20 types of them belonged to the growing tree areas. As the plots, the 125 places(unit area: $400m^2$) were established the types of the trees found were distributed in the range where the minimum was 1 type, the maximum was 9, the mean was $4.4{\pm}1.5$, and the mode was 4 types. The number of the trees found was distributed in the range where the minimum was 17, the maximum was 125, the mean was $4.4{\pm}1.5$, and the mode was 70. In the DBH, the minimum was 6 cm, the maximum was 30 cm, the mean was 13 cm and the mode was 10 cm. As the result of measuring the age of the 5 trees corresponding to the value of the mode in DBH, selected among the dominant species by the plots, less than 20 years was 17 places, the 115 places were included in the range from 21 to 30 years, and more than 31 years was the 6 places.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.229-236
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• 2017

An efficient frequent pattern algorithm is essential for mining association rules as well as many other mining tasks for convergence with its application spread over a very broad spectrum. Models for mining pattern have been proposed using a FP-tree for storing compressed information about frequent patterns. In this paper, we propose a centroid frequent pattern growth algorithm which we called "CAWFP-Growth" that enhances he FP-Growth algorithm by making the center of weights and frequencies for the itemsets. Because the conventional constraint of maximum weighted support is not necessary to maintain the downward closure property, it is more likely to reduce the search time and the information loss of the frequent patterns. The experimental results show that the proposed algorithm achieves better performance than other algorithms without scarifying the accuracy and increasing the processing time via the centroid of the items. The MapReduce framework model is provided to handle large amounts of data via a pseudo-distributed computing environment. In addition, the modeling of the proposed algorithm is required in the fully distributed mode.