• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.394-397
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• 1999

Impact ionization, which is a kind of a carrier-carrier interaction process occurring in a semiconductor under the influence of a high electric field, is necessary to analyse carrier transport properties. Since the parabolic or nonparabolic E-k relation is different from real band structure in high energy range, exact model of impart ionization have been presented using full band I-k relation and Fermi's golden rule. We have investigated relation of density of states, energy band structure and overlap integral. We make use of empirical pseudopotential method in order to calculate energy band structure of silicon, tetrahedron method in order to calculate density of states. We know density of states very depends on energy band structure and overlap integral depends on the primary electron energy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.93-98
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• 1999

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, Any-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed Any-PACS consists of mainly four parts such as Web Module, Client-Server Module, Internal Module, Acquisition Module. In addition, Any-PACS system includes DICOM Converter that Non-DICOM file format converts standard file format. In Client-Server Module case, Proposed system is combined both SCU(Service Class Use: Client) part and SCP(Service Class provider: Server)part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for Medium and Small hospitals to install and operate the full-PACS. Also, we constructed Web Module for database connection through the WWW.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.419-425
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• 2001

In land mobile communications, multipath fading is one of the key factors which affect the system performance. Some extensive studies have been carried out to improve the degraded performance under this fading channels. The PSAM channel compensation method using channel fading estimation is widely used and TCM is a combined coding and modulation technique that has been shown to provide significant coding gain without increasing the transmission bandwidth. In this paper, we analyze the performance of PSA-TC-8PSK which combines PSAM and TCM over frequency nonselective fading channels. To estimate channel fading, Wiener filter which minimizes error variance is used as compensation method and we analyze the affects on the system performance of the number of filter taps, period of the pilot symbol frame, and the Doppler frequency. In addition, we consider the symbol timing recovery circuit which can be implemented in the full-digital method and analyze the effects of symbol timing error on the system performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1095-1104
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• 2000

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, mini-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed mini-PACS consists of mainly four parts such as web module, client-server module, internal module, acquisition module. In addition, mini-PACS system includes DICOM converter that non-DICOM file format converts standard file format. In client-server module case, proposed system is combined both SCU (service class user: client) part and SCP(service class provider: sewer)part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for medium and small hospitals to install and operate the full-PACS. Also, we constructed web module for database connection through the WWW.

• Journal of the Korean Society for information Management
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• v.19 no.3
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• pp.211-326
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• 2002

This study is to analyze and evaluate copyright protection environment in digital reproduction and transmission, find out problems involved. and suggest recommendations for improvement. Data was collected 50 libraries to which digital reproduction and transmission is permitted under the Copyright Act were surveyed to examine the present states of digitalization and the systems employed. Also, library users, sampled from 5 libraries carrying out all the 6 technical measures obliged by the Copyright Act, were surveyed to examine their use of digital materials and perception on the copyright. After reviewing descriptive statistics, frequency and cross-tabulation analysis were made. The results of the analysis are most of the libraries. except for the industry university libraries, have implemented digital library systems, but the introduction rate of both digital reproduction system and transmission system are high (68.0% and 84.0%. respectively), while that of copyright protection system was low (26.0%). 84.0% of the libraries surveyed digitalize the full text, but the Libraries have digital collection less than 5,000 items, and only 33.3% of them digitalize materials with securing the copyrights. Regulations on copyright protections are not obliged properly. and it appeared that not only users' perception and perception of copyright as well as their use of electronic books are relatively low.

• Journal of Korea Multimedia Society
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• v.15 no.11
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• pp.1349-1357
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• 2012

In recent years, security accidents which are becoming the socially hot issue not only cause financial damages but also raise outflow of private information. Most of the accidents have been immediately caused by the software weakness. Moreover, it is difficult for software today to assure reliability because they exchange data across the internet. In order to solve the software weakness, developing the secure software is the most effective way than to strengthen the security system for external environments. Therefore, suggests that the coding guide has emerged as a major security issue to eliminate vulnerabilities in the coding stage for the prevention of security accidents. Developers or administrators effectively in order to use secure coding coding secure full set of security weaknesses organized structurally and must be managed. And the constant need to update new information, but the existing Secure Coding and Security weakness is organized structurally do not. In this paper, we will define and introduce the structured weakness for mobile applications by the surveys of existing secure coding and coding rules for code analysis tools in Java.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2231-2238
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• 2011

In this paper, the extract method of eye and eye-line from picture of a person is proposed. Most of existing papers are to extract the position of eyeball but in this paper, by extracting not only the position of eyeball but also eye-line, it can be applied to the face application program variously. The experimental data of the input picture is a full face photograph taken by smart phone, basically the picture is limited to the face of one person and back ground can be taken from every where and no restriction of race. The proposed method is to extract face candidated area by using Harr Classifier and set up the candidate area of eye position from face candidate area. To extract high value from eye candidate area using dilate operation, and proposed the method to classify eye and eyelash by local thresholding of the picture. After that, using thresholding image from eyemapC that Hsu's suggested, and separated the area with eye and without eye. Finally extract the contour of eye and detect eye-line using optimum ellipse estimation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.981-989
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• 2015

In a log likelihood ratio(LLR) calculation of the detected symbol, multiple-input multiple-output(MIMO) system applying an optimal or suboptimal algorithm such as a maximum likelihood(ML) detection, sphere decoding(SD), and QR decomposition with M-algorithm Maximum Likelihood Detection(QRM-MLD) suffers from exponential complexity growth with number of spatial streams and modulation order. In this paper, we propose a LLR calculation method with very low complexity in the QRM-MLD based symbol detector for a high order modulation based $N_T{\times}N_R$ MIMO system. It is able to approach bit error rate(BER) performance of full maximum likelihood detector to within 1 dB. We also analyze the BER performance through computer simulation to verify the validity of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.481-487
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• 2014

In this paper, we have proposed gigabit serial transceiver based on backplane architecture at the satellite communication digital transponder. The transponder supports the full combinational switching function with broadband multi-channel using programmable device - Xilinx space-grade Virtex-5 FPGA. In order to implement the switching function, GTX transceiver solution inside Virtex-5 FPGA is used. Also hardware implementation is simple because of no additional component. In order to use a GTX transceiver, signal integrity(SI) simulation of PCB design is essential. We investigate the characteristics of the S-parameter, eye diagram, channel jitter of GTX transmission line and conform that GTX Transceiver operates without error. Finally the proposed PCB design will be utilized at satellite communication digital transponder EQM-2(Engineering Qualification Model-2).

• KIPS Transactions on Software and Data Engineering
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• v.4 no.4
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• pp.187-194
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• 2015

In this paper, we present an effective visual odometry estimation system to track the real-time pose of a camera moving in 3D space. In order to meet the real-time requirement as well as to make full use of rich information from color and depth images, our system adopts a feature-based sparse odometry estimation method. After matching features extracted from across image frames, it repeats both the additional inlier set refinement and the motion refinement to get more accurate estimate of camera odometry. Moreover, even when the remaining inlier set is not sufficient, our system computes the final odometry estimate in proportion to the size of the inlier set, which improves the tracking success rate greatly. Through experiments with TUM benchmark datasets and implementation of the 3D scene reconstruction application, we confirmed the high performance of the proposed visual odometry estimation method.