• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.113-118
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• 2006

Recently, wireless LANs are often applied in home or office because of its various of convenience. Frequency rage of wireless LANs specified by IEEE 802.11b is at 2.4 GHz. The bluetooth, the microwave oven, and the PDA(Personal Digital Assistants) uses ,however, the same frequency band. So problems will be produced in these environments, such as multi-pass interference and system-to-system interference. These problems can be eliminated by using EM wave absorber. In this paper, we designed and fabricated EM wave absorber using Sendust, $Al(OH)_3$, and CPE. The double-layered EM wave absorber with thickness of 1.5 mm has absorption ability more than 10 dB at 2.4 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.906-912
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• 2012

A ship ad-hoc network (SANET) can provide ships with diverse multimedia services by replacing expensive satellite communications. While ITU-R M. 1842-1, standards for maritime VHF band digital communications, can be used as the specifications of physical layer for SANETs, no standards are specified for higher layers of SANETs. In this paper, we propose a ship ad-hoc communication (SAC) protocol for SANETs, based on medium access control (MAC) and routing protocols for terrestrial ad-hoc networks. SAC protocol is a cross-layer protocol which combines MAC and routing into one algorithm and considers maritime environments, including the existence of neighboring ships, the possibility of routing to a destination, and changing the communication mode in case of VHF channel failure.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.865-868
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• 2007

Recently, wireless LANs are often applied in home or office because of its various of convenience. Frequency range of wireless LANs specified by IEEE 802.11b is at 2.4 GHz. The bluetooth, the microwave oven, and the PDA(Personal Digital Assistants) uses, however, the same frequency band. So problems will be produced in these environments, such as multi-pass interference and system-to-system interference. These problems can be eliminated by using EM wave absorber. In this paper, we designed and fabricated EM wave absorber using MnZn-Ferrite, Sendust, and CPE( Chlorinated Polyethylene). The EM wave absorber with the ratio of material (MnZn-Ferrite : Sendust : CPE = 64 : 16 : 20 wt.%) has thickness of 3.7 mm and absorption ability more than 17 dB at 2.4 GHz.

• Journal of Information Technology Services
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• v.16 no.1
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• pp.139-162
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• 2017

Museums contain a significant meaning as a place that reflects empirical knowledge that have been accumulated socially and scientifically in overall life of the public and provides the opportunity to enjoy prestigious culture, while serving as the extended place of education. The first objective of this study is to increase the accessibility of general public through the development of online museum programs as service contents and to present the ultimate direction the development of in art appreciation contents that can effectively expand the infrastructure of culture and art. Second, the effectiveness of online art appreciation programs by registered private museums, which continuously develop smart media-based online museum contents and systemization of archive as the distribution rate of smart devices is increased due to generalization of digital environments, was analyzed by each case to examine the objective distinctions strategies. Third, in terms of museum visitors and smart contents users, this study examines the expected effects of popular distribution by seeking various ways that can enhance the desired exhibit appreciation and autonomous utilization of educational programs, while not being restricted by the physical accessibility and limitation of space at the museums. The subjects of this study included cases of BoroomSan Museum, Savina Museum of Contemporary Art, Imageroot, Sangwon Museum of Art, Hello Museum, etc. and the online smarts contents art appreciation educational programs by registered private museums were analyzed. Results expected to achieve from such processes are as follows. First, the possibility to expand cultural participation in museum exhibition appreciation and museum education infrastructure became widen. Second, the educational program resources can be utilized as the culture and art asset that strengthens the museums' responsibilities in their social role. Third, museum archive can be constructed in more systematic way, and the efficiency of museum archive system can be enhanced to maintain the museum collection database in a consistent format. Fourth, the museum's smart contents users' continued access to museum's online contents may induce the exhibition effect of the site and voluntary participation in education, and can also expect an economic synergy effect as the users become potential visitors that may actually visit the museum in the future.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.2
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• pp.71-76
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• 2016

Digital image processing is being utilized in various fields including medical industry, satellite photos, and factory automation image recognition. However, this kind of image data produces heat by an external cause in the course of being processed, transmitted, and stored. Most typical noises added in the images are AWGN and salt and pepper. MF, CWMF, and AWMF are methods used to restore images damaged by AWGN and the existing methods are likely to damage detailed information such as an edge. Therefore, this paper suggests an algorithm applying weight of average filter, average filter depending on pixel, and spatial weight filter based on edge size of local mask in an AWGN environment, in a different way. Also, this paper compares functions of existing methods by using PSNR to prove excellence of the suggested algorithm.

• The Journal of Information Technology
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• v.1 no.1
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• pp.173-188
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• 1998

In this paper we discussed various types of electronic payment schemes that are emerging. Threats vary from malicious hackers attempting to crash a system, to threats to data or transaction integrity. An understanding of the various types of threats can assist a security manager in selecting appropriate cost-effective controls to protect valuable information resources. An overview of many of today's common threats presented in this paper will be useful to mangers studying their own threat environments with a view toward developing solutions specific to their organization. To ensure security on the Internet, several methods have been developed and deployed. They include authentication of users and servers, encryption, and data integrity. Transaction security is critical : without it, information transmitted over the Internet is susceptible to fraud and other misuse. So computer systems represents an Intermediary with the potential to access the flow of information between a user. Security is needed to ensure that intermediaries cannot eavesdrop on transactions, or copy/modify data. Online firms must take additional precautions to prevent security breaches. To protect consumer information, they must maintain physical security of their servers and control access to software passwords and private keys. Techniques such as secret and public-key encryption and digital signatures play a crucial role in developing consumer confidence in electronic commerce.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.542-554
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• 2007

Seamless streaming of multimedia content via heterogeneous networks to viewers using a variety of devices has been a desire for many multimedia services, for which the multimedia contents should be adapted to usage environments such as network characteristics, terminal capabilities, and user preferences. Scalability in video coding is one of attractive features to meet dynamically changing requirements of heterogeneous networks. Currently a new scalable video coding (SVC) is standardizing in the Joint Video Team (JVT) of the ISO/IEC Moving Picture Experts Group (MPEG) and the ITU-T Video Coding Experts Group (VCEG), which will be released as Extension 3 of H.264/MPEG-4 AVC. In this paper, we introduce new technologies of SVC and evaluate performance of it especially regarding on overhead bit-rate and coding efficiency to support spatial, temporal, and quality scalability.

• Journal of Korea Technology Innovation Society
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• v.20 no.4
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• pp.1036-1056
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• 2017

The rapid increase of ageing population and chronic disease patients cause high medical expenses, and it led an increased attention to digital healthcare. Smart car technologies for healthcare have been developing to recognize drivers' status and predict diverse driving environments. The present study aimed to understand the research trends of autonomous vehicle technologies of Korea and the United States through time series analysis, network analysis, visualization, and comparison between the two countries. The results suggest that cooperative study needs to be done in common research areas such as driver's safety and algorithms. It is also needed to conduct studies and benchmark about liking technique related to part-to-part and vehicle-to-vehicle as America's competitive advantaged area. In the US, diverse approaches of autonomous vehicle technologies have used to consider the characteristics of various age groups and passengers' health status through sensor, while in Korea, only one aspect, older drivers, is mentioned. Implications for the development direction of autonomous vehicle technologies with competitiveness in considering public health, ethics, and driver's safety and convenience are discussed in detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5486-5492
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• 2011

This paper presents a model of ubiquitous learning environment system based on the concepts of ubiquitous computing technology that enables learning to take place anywhere at anytime. This ubiquitous learning environment is described as an environment-friendly learning scheme that supports students' learning using digital media in geographically distributed environments. The u-learning model is a web-based e-learning system that could enable learners to acquire knowledge and skills through interaction between them and the ubiquitous learning environment. Education is happening all around the student but the student may not even be conscious of the learning process. Source data is present in the embedded objects and students do not have to do anything in order to learn. The communication between devices and the embedded computers in the environment allows learners to learn in an environment of their interest while they are moving, hence, attaching them to their learning environment.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.12
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• pp.673-681
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• 2004

As the use of digital videos is getting popular, there is an increasing demand for efficient browsing and retrieval of video. To support such operations, effective video indexing should be incorporated. One of the most fundamental steps in video indexing is to parse video stream into shots and scenes. Generally, it takes long time to parse a video due to the huge amount of computation in a traditional single computing environment. Previous studies had widely used Round Robin scheduling which basically allocates tasks to each slave for a time interval of one quantum. This scheduling is difficult to adapt in a heterogeneous environment. In this paper, we propose two different parallel parsing algorithms which are Size-Adaptive Round Robin and Dynamic Size-Adaptive Round Robin for the heterogeneous distributed computing environments. In order to show their performance, we perform several experiments and show some of the results.