• International Journal of Reliability and Applications
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• v.3 no.2
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• pp.61-80
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• 2002

Tree-harvesting worker data of 508 separate worker accidents are analyzed and an exploratory approach taken. The worker accident data cover a sample of five years. The scope of the study was the southeastern United States of America. As might be hypothesized, the chainsaw was the most hazardous type of tree-harvesting equipment. It accounted for 55％ of the tree-harvesting accidents. Most chainsaw accidents resulted in injuries to the lower extremities and were more frequent among younger employees. The probability of one or more chainsaw accidents occurring in any 30-day period was approximately 0.856. Chainsaw accidents were more likely to occur in late morning and early afternoon. We used statistical tools such as Pareto charts, c-charts and Ishikawa diagrams. Such tools are useful in diagnosing the root-cause of tree-harvesting worker accidents and help in developing preventive safety programs. Recommendations to help improve the quality of information of accident data collected by insurance companies and others are briefly given. The strategy and culture of continuous process improvements are stressed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1083-1093
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• 1993

Recently, some applications require the multicast service that transmit messages to multiple destinations in computer communication network enviroment. Multicast service is to send messages to the group which consists of a number of processes. A multicast group is a collection of processes which are destinations of the transmitted messages and these processes may run on one or more hosts. Therefore, it is important to manage each member of process groups in order to provide efficient multicast services. In this paper, we design and implement group management system to support multicast services. Group Management System was designed with Process Group Management System(PGMS) and Host Group Management System(HGMS). We have implemented basic primitives of PGMS, HGMS. Also, membership tree management algorithm is designed and implemented. Membership tree provides the relation of the members of multicast groups and routing Informations.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.878-881
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• 2008

To index the object's trajectory is an important aspect in moving object database management. This paper implements an optimizing index structure named Rend 3D R-tree based on 3D R-Tree. This paper demonstrates the time period update method to reconstruct the MBR for the moving objects in order to decrease the dead space that is produced in the closed time dimension of the 3D R-tree, then a rend method is introduced for indexing both current data and history data. The result of experiments illustrates that given methods outperforms 3D R-Tree and LUR tree in query processes.

• Korean Journal of Remote Sensing
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• v.27 no.6
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• pp.703-715
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• 2011

Forests have been considered one of the most important ecosystems on the earth, affecting the lives and environment. The sustainable forest management requires accurate and timely information of forest and tree parameters. Appropriately interpreted remotely sensed imagery can provide quantitative data for deriving forest information temporally and spatially. Especially, analysis of individual tree detection and crown delineation is significant issue, because individual trees are basic units for forest management. Individual trees in aerial imagery have reflectance characteristics according to tree species, crown shape and hierarchical status. This study suggested a method that identified individual trees and delineated crown boundaries through adopting gradient method algorithm to amplified greenness data using red and green band of aerial imagery. The amplification of specific band value improved possibility of detecting individual trees, and gradient method algorithm was performed to apply to identify individual tree tops. Additionally, tree crown boundaries were explored using spectral intensity pattern created by geometric characteristic of tree crown shape. Finally, accuracy of result derived from this method was evaluated by comparing with the reference data about individual tree location, number and crown boundary acquired by visual interpretation. The accuracy ($\hat{K}$) of suggested method to identify individual trees was 0.89 and adequate window size for delineating crown boundaries was $19{\times}19$ window size (maximum crown size: 9.4m) with accuracy ($\hat{K}$) at 0.80.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.3
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• pp.79-89
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• 2013

This paper proposes a watermarking scheme to protect ownership of a digital hologram, an ultra-high value-added content. It performs pre-defined levels of quad-tree Fresnelet transforms. The relationship among the same-positional-blocks is extracted as the digital pre-watermark. For the relationship, we use properties of a digital hologram that a hologram pixel retains all the information of the object and that the same size of partial holograms reconstructs the same size of object but different in their view points. Also we mix a set of private data with the pre-watermark and the result is encrypted by a block cipher algorithm with a private key. Experimental results showed that the proposed scheme is very robust for the various malicious and non-malicious attacks. Also because it extracts the watermarking data instead of inserting, the watermarking process does not harm the original hologram data. So, it is expected to be used effectively for invisible and robust watermark for digital holograms.

• Information Systems Review
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• v.8 no.3
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• pp.125-134
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• 2006

This article adopts a decision tree algorithm(C5.0) to predict customer churning in online auto insurance environment. Using a sample of on-line auto insurance customers contracts sold between 2003 and 2004, we test how decision tree-based model(C5.0) works on the prediction of customer churning. We compare the result of C5.0 with those of logistic regression model(LRM), multivariate discriminant analysis(MDA) model. The result shows C5.0 outperforms other models in the predictability. Based on the result, this study suggests a way of setting marketing strategy and of developing online auto insurance business.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.678-691
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• 2000

A variety of multimedia applications require multimedia database management systems to manage multimedia data, such as text, image, and video, as well as t support content-based image or video retrieval. In this paper we design and implement a content-based image retrieval system, BADA-IV/I$^2$R(Image Information Retrieval), which is developed based on BADA-IV multimedia database management system. In this system image databases can be efficiently constructed and retrieved with the visual features, such as color, shape, and texture, of image. we extend SQL statements to define image query based on both annotations and visual features of image together. A high-dimensional index structure, called CIR-tree, is also employed in the system to provide an efficient access method to image databases. We show that BADA-IV/I$^2$R provides a flexible way to define query for image retrieval and retrieves image data fast and effectively: the effectiveness and performance of image retrieval are shown by BEP(Bull's Eye Performance) that is used to measure the retrieval effectiveness in MPEG-7 and comparing the performance of CIR-tree with those of X-tree and TV-tree, respectively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.83-91
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• 2008

IISO/IEC 9594-8 defines the public key framework and attribute certificate framework. Attribute certificate framework deals with privilege management infrastructure(PMI). In PMI, for privilege management using attribute certificates, role assignment certificates and role specification certificates are used to assign and specify privileges independently. Role specification certificates includes privilege specifications and the details far privilege management of network environments. Privilege management of unreliable network environment tries to enhance the reliability and efficiency of privilege information transmission forwarding over unreliable routes in the presence of potentially faulty nodes and edges. Each node forms a role specification tree based on role specification relationship data collected from the network. In this paper privilege management cost with the role specification certificates tree structure is evaluated trying to reduce the overhead incurred by role creation and modification of privileges. The multicasting of packets are used for scalability. We establish management cost model taking into account the packet loss and node reliability which continuously join and leave for network. We present quantitative results which demonstrate the effectiveness of the proposed privilege management scheme.

• Industrial Engineering and Management Systems
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• v.4 no.1
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• pp.102-108
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• 2005

This paper studies medical data classification methods, comparing decision tree and system reconstruction analysis as applied to heart disease medical data mining. The data we study is collected from patients with coronary heart disease. It has 1,723 records of 71 attributes each. We use the system-reconstruction method to weight it. We use decision tree algorithms, such as induction of decision trees (ID3), classification and regression tree (C4.5), classification and regression tree (CART), Chi-square automatic interaction detector (CHAID), and exhausted CHAID. We use the results to compare the correction rate, leaf number, and tree depth of different decision-tree algorithms. According to the experiments, we know that weighted data can improve the correction rate of coronary heart disease data but has little effect on the tree depth and leaf number.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.59-65
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• 2012

Emergency medical information center performs role of medical direction about disease consult and pre-hospital emergency handling scheme work to people. Emergency medical information system plays a major role to be decreased mortality and disability of emergency patient by providing information of medical institution especially when emergency patient has appeared. But, various attacks as a hacking have been happened in Emergency medical information system recently. In this paper, we proposed security structure which can protect the system securely by detecting attacks from outside effectively. Intrusion detection was performed using rule based detection technique according to protocol for every packet to detect attack and intrusion was reported to control center if intrusion was detected also. Intrusion detection was performed again using decision tree for packet which intrusion detection was not done. We experimented effectiveness using attacks as TCP-SYN, UDP flooding and ICMP flooding for proposed security structure in this paper.