• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.493-498
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• 2005

P2P service is a method that can share various information through direct connection between computer of a person who have information and a Person who have information without server in the Internet and it is getting a lot of popularity by method for free ex change of file. P2P file sharing systems have become popular as a new paradigm for information exchange. Because all users who use service in P2P file sharing system can use shared files of several users freely by equal access privilege, it is happening the 'free rider' that only download shared file of other users without share own files. Although a user share a malicious file including virus, worm or file that have title differing with actuality contents, can use file sharing service without limitation. In this paper, we propose a method that restrict access of 'free rider' that only download using reputation information that indicate reliability of user. Also, we restrict usage ons hared file of other users about users who share harmful file.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.919-926
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• 2002

In this paper, new multicast scheduling algorithms are proposed for the WDM single-hop broadcast-and-select networks. The existing multicast scheduling algorithms are focused on the partitioning a multicast group into several subgroups to reduce the delay time of each receiver. These partitioning algorithms are grouping method of the receivers already tuned to the transmitter's wavelength. However, these algorithms ignore the state of receivers, which leads to increase the number of subgroups and the delay time. Therefore, 1 propose two new multicast scheduling algorithms called H_EAR and PGM that partition a multicast group to subgroups using the tunable transmitter, state information of receivers, and pseudo group concept. The performance of proposed algorithms are evaluated through the computer simulation. They show the better performance comparing with the existing multicast scheduling algorithm.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.3
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• pp.181-189
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• 2004

This paper describes the method for detecting vehicles in the rear and rear-side at night by using headlight features. A headlight is the outstanding feature that can be used to discriminate a vehicle from a dark background. In the segmentation process, a night image is transformed to a binary image that consists of black background and white regions by gray-level thresholding, and noise in the binary image is eliminated by a morphological operation. In the feature extraction process, the geometric features and moment invariant features of a headlight are defined, and they are measured in each segmented region. Regions that are not appropriate to a headlight are filtered by using geometric feature measurement. In region classification, a pair of headlights is detected by using relational features based on the symmetry of a pair of headlights. Experimental results show that this method is very applicable to an approaching vehicle detection system at nighttime.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2129-2137
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• 2015

Lots of research and development works have been actively focused on the self-driving vehicles, locally and globally. In order to implement the self-driving vehicles, lots of fundamental core technologies need to be successfully developed and, specially, it is noted that traffic lights detection and recognition system is an essential part of the computer vision technologies in the self-driving vehicles. Up to nowadays, most conventional algorithm for detecting and recognizing traffic lights are mainly based on the color signal analysis, but these approaches have limits on the performance improvements that can be achieved due to the color signal noises and environmental situations. In order to overcome the performance limits, this paper introduces the morphological analysis for the traffic lights recognition. That is, by considering the color component analysis and the shape analysis such as rectangles and circles simultaneously, the efficiency of the traffic lights recognitions can be greatly increased. Through several simulations, it is shown that the proposed method can highly improve the recognition rate as well as the mis-recognition rate.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.5
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• pp.352-365
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• 2012

A primary study on the rapid modeling of storm surge, which is one of typical coastal disasters, for immediate forecasting in conjunction with typhoon advisories is done and tested for the typhoons Bolaven, Tembin and Sanba which attacked to Korean Peninsula on August and September in this year 2012. Semi automatic rapid computations according to JTWC typhoon advisories were performed and uploaded to the web by models SLOSH in PC and ADCIRC in parallel clusters with 64 cores having 57k nodes encompassing the North-Western Pacific region. It only takes 1 and 2 hours from taking advisory to web uploading, respectively. By comparison with observed water surface elevations for the major tidal stations after Bolaven attack it shows within RMS error of 0.17~0.19 m for surge heights and only deviates 1 hour of peak surge time in ADCIRC model. Thus it is concluded that this approach provides a frame of near real-time immediate forecasting of storm surges with satisfactions.

• Archives of design research
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• v.18 no.3 s.61
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• pp.191-198
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• 2005

Menu is the most common interaction tool to select and execute a specific menu item from multiple menu options. With the very rapid increasing amount of information, various new menu designs have been developed. In this research, the pull-down menu, fisheye menu and grid menu were tested to compare the performance time, error rate, simplicity, usefulness, user friendliness, and overall user preference of each menu type. The grid menu was more efficient in selection speed than the pull-down and fisheye menus when the number of menu-items was 50 and 100. The time needed to choose a menu-item with a grid menu was less affected by the size of menu. The pull-down and the grid menus were considered to be more satisfactory, simple, user friendly, and useful than the fisheye menu. 42.3 percent of subjects indicated that the grid menu was their preferred selection tool among the menus. The grid menu is an efficient and robust alternative menu choice for small and middle size menu list. Further study is required to examine the possibility of grid menu on mobile devices.

• Archives of design research
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• v.19 no.2 s.64
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• pp.273-282
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• 2006

The earlier animations aimed to express the characters realistically by making the illustrations look like moving and alive. Since then, animations have been influenced by development of media technology, men's changed mentality and evolvement of diverse social phenomena, while influencing them, too. Among them, the computer which emerged first in 1946 has sewed to more diversify the tools for realistic expressions of animations, and further, enhance the intellectual power of expression media only to expand the new visual expressions and thereby, usher in a multi-media video information environment. Moreover, this technology or computer has urged every discipline to disintegrate its conventional order for the post-modernism characterized by polysemous, diversified, obscure and sometimes, mutually contradicting elements, and as a result, animations had to find a new breakthrough in the conventional reality (cognitive and reflective reality). Thus, animations have been real enough to be perceived impromptu and emotionally, faster than the logical cognitive process beyond the simple technological barrier or the screen image processing. With such backgrounds in mind and by defining such a reality as 'sensuous reality', this study aimed to apply Gilles Deleuze's, reality of space to animation films and interpret it.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.10-14
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• 2008

Computer-animated crowd scenes are often observed in computer games and feature films. The common way to model locomotion of large human crowds is to employ agent based methods where the behavior of each person is independently modeled. But for large crowds, it is difficult for a user to control all the individuals using individual behavior model. Instead, crowd behaviors can be controlled more intuitively at the group level than at the individual level. In this paper, we present the group force field model to simulate path following behavior for groups. A group is a set of characters who have the same goals, i.e. the same path to follow. We also define three characteristics of grouping behavior: alignment, cohesion, and distribution. Our group force field model preserves these characteristics while avoiding collisions. By using our model, user can generate desired group behaviors from line-up behavior to lumped one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.829-832
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• 2006

The word P2P implies significant changes in current business dynamics. The P2P service enables individuals to be connected to the Internet for the direct provision of information and even downloads from one another without the conventional method of passing through search engines. This can be utilized to extend the path of retrieving information from limited web sites to personal and enterprise databases. That is, it is now possible for individuals to manage their own information on a national or global scope, share various information with other members, form communities of users interested in sharing homogeneous information, and utilize remote conference and remote education using groupware.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1861-1868
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• 2014

In wireless communication systems, a frequency offset exist at the received signal due to the transmitter-receiver oscillator mismatch and Doppler effect in mobile environments. Those offsets rotate the received signal's phase and degrade the receiver performance. Hence, estimation and compensation of the frequency offset is crucial at the receiver. This paper proposes a new frequency offset estimation technique based on partial correlation. The proposed method requires less computational complexity than that of the conventional method. In addition, since the proposed one can estimate a wide range of frequency offset without estimation accuracy loss, the application of the method is desirable for the communication environments that have a large frequency offset. In order to verify the performance of our proposed scheme, a series of computer simulations have been carried out and compared against those of the conventional method.