• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.1-10
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• 2013

With the help of information technology, PVR has been evaluated as an innovative device that brings epochal changes for program selection and convenience of receivers with the convergence between broadcasting and telecommunication. Satellite broadcasters introduced PVR service to strengthen its interactive function. This study analyzed PVR user behavior and how it changed the existing TV viewing behavior through satellite subscribers. The results revealed that PVR subscribers mainly used it for time shifting like VCR use. FUrthermore, heavy PVR users watched TV more than on average and enjoyed a divers genre of programs. This study provides scholarly implication for PVR using behavior and its effects and its useful information for contents and marketing strategy to help PVR service popularization.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.181-191
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• 2010

Lightweight panels are currently used in many ways, such as inner walls of the skyscrapers and residential buildings in Korea. Moreover there has been an increasing of interest in developing construction method and quality improvement as many buildings became higher, because there are more advantages like constructability, finishability, and economic efficiency, etc. than previous heavy weight concrete wall. It is necessary to analyze the characteristics and evaluate the performance of lightweight panels when selecting proper methods and materials to building characteristics and builder's demand. However, there doesn't exist systematic data with a classification of lightweight panels' type and performance. The purpose of this study is to classify domestic lightweight panels by both type of exterior board and construction method, and also to evaluate each performance by surveying user's opinion.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.59-67
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• 1998

In this paper, a rigorous three-dimensional Monte Carlo approach to simulate the sputter yield as a function of the incident ion energy and the incident angle as well as the atomic ejection distribution of the target is presented. The sputter yield of the target atom (Cu, Al) has been calculated for the different species of the incident atoms with the incident energy range of 10 eV ~ 100 KeV, which coincides with the previously reported experimental results. According to the simulation results, the calculated sputter yield tends to increase with the amount of the energy of the incident atoms. Our simulation revealed that the maximum sputter yield can be obtained for the incident atom with 10 KeV for the heavy ion, while the maximum sputter yield for the light ion is for the incident atoms with an energy less than 1 KeV. The sputter yield increases with angle of incidence and seems to have the maximum value at 68$^{\circ}$. For angular distributions of the sputtered particle, the atoms in the direction normal to the surface increase with angle of incidence. Furthermore, we has conducted the parallel computation on CRAY T3E supercomputer and built a GUI(Graphic User Interface) system running the sputter simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.858-865
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• 2006

A certificate that is issued by the certification authority can be revoked within the period of validity by various reasons such as the loss of private key, disqualification or the change in key. Therefore, the certificate status verification must precede prior to use Currently, the CRL or the OCSP methods are used in most cases. But the CRL system can't guarantee the present status of the certificate, and the OCSP generates heavy network traffic by checking or requesting certificate status in real-time using high-capacity messages. In this paper, we propose a system that requests the certificate verification by creating VDN for user identity information. Through this system, the certification authority will be able to guarantee the certificate's status in real-time, and solve the problem of the sewer and network overload by verifying and finding user identity information from VDN, Based on the results, we propose a real-time certificate status verification system which can improve the speed of the verification. We confirmed the improvement in speed by testing and comparing it with the existing methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.11-20
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• 2008

Three-party key exchange protocol is a cryptographic protocol which permits two clients share a common session key using different passwords by the help of a trusted server. In a three-party key exchange protocol, an user remember only one password which shared with a trusted server for establish a common key with another user. The trusted server should participate in an execution of the protocol between two clients. This impose heavy burden on the server when many users want to establish a session key using the protocol. In this paper, we propose a three-party key exchange protocol based on a smart card which reduce the computational complexity and communication overhead for the trusted server. In our protocol, the server does not participate in an key exchange procedure between two clients.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.139-148
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• 2005

The desired level for multimedia services in the mobile web environment, the next generation web environment, is expected to be of PC level quality. And great efforts have been made in the development of hadware technology, communication technology, various kinds of services and standardization to support these services, In the mobile web environment, multimedia contents adaptation services should be available through supporting various kinds of devices, network abilities and users' preferences. It means that due to the variety of both desired devices' hardware specifications, called destinations, and desired QoSes, the QoSes in the destinations are not fixed or defined. If a new user wants to stream multimedia contents in a server through a new kind of terminal device, it should be considered whether the existing transcoders are able to adapt the multimedia contents. However, the existing libraries for multimedia adaptation have heavy transcoder figures which include all adaptive functions in one library, The challenge of universal access is too complex to be solved with these all in one solutions. Therefore, in this paper we propose an application independent multimedia adaptation framework which meets the QoS of new and varied mobile devices. This framework is composed of a group of unit transcoders having only one transcoding function respectively, Instead of heavy transcoders. Also, It includes the transcoder manager supporting the dynamic connections of the unit transcoders in order to satisfy end to end QoS.

• Journal of Korea Multimedia Society
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• v.15 no.2
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• pp.273-280
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• 2012

Recently, our society is affected by frequent occurrence of disaster such as local heavy rain and landslide. So, disaster organization and facility are stepping up their efforts to establish an effective disaster information system. Especially, researches of smartphone based disaster information service are conducted actively because smartphone becomes an ubiquitous to society and has various advantages. However, in general, these services only provide simple disaster information and do not consider several elements that is desired by the situation and conditions. Therefore, this paper establishes efficient disaster information service through implementation of application that connect disaster collection system and ability to search disaster information according the terms desired of user.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.134-141
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• 2003

A major research issue associated with service robots is the creation of an environment recognition system for mobile robot navigation that is robust and efficient on various environment situations. In recent years, intelligent autonomous mobile robots have received much attention as the types of service robots for serving people and industrial robots for replacing human. To help people, robots must be able to sense and recognize three dimensional space where they live or work. In this paper, we propose a three dimensional environmental modeling method based on an edge enhancement technique using a planar fitting method and a neural network technique called "Growing Neural Gas Network." Input data pre-processing provides probabilistic density to the input data of the neural network, and the neural network generates a graphical structure that reflects the topology of the input space. Using these methods, robot's surroundings are autonomously clustered into isolated objects and modeled as polygon patches with the user-selected resolution. Through a series of simulations and experiments, the proposed method is tested to recognize the environments surrounding the robot. From the experimental results, the usefulness and robustness of the proposed method are investigated and discussed in detail.in detail.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.1235-1243
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• 2015

The purpose of this study was to find if the password composition of domestic users is affected by the different form of the word 'Password' in the interface of login or password change. In particular, 'Password', foreign notation, and 'Secret Number', notation translated by Korean, have a semantic difference. According to the survey of 200 students in S university, passwords made under the word 'Secret Number' are heavy on numbers than alphabet. Because these passwords make much smaller composition space than another case, they have bad security impact. We expect to make use of this paper as a base line data for study to find how improve domestic user's password security.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.5 s.149
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• pp.619-629
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• 2006

The safety assessment of the structure related to people has become the most important part in the process of the design. Especially, in the case of a ship, as regulations about the safety of passengers and the pollution in the ocean are strictly reinforcing, the safety assessment has become the most important part in the process of the design. In this paper, we suggested network-based simulation system framework using HLA (High Level Architecture) among many kind of simulations to assess the safety of the ship. In addition, the visualization method which is composed of graphic user interface for ship modeling and the visualization of ship motion is presented.