• International Commerce and Information Review
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• v.19 no.4
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• pp.29-50
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• 2017

In emerging technologies, innovation processes are dynamic in that the government needs to regularly review its policies to resonate with rapid technological advancements, changing public needs, and evolving global trends. In the 1990s, the Internet grew at an explosive rate, but many applications were constrained due to security concerns. Public Key Infrastructure (PKI) seemed to be the fundamental technology to address these concerns by providing security functions. As of 2017, PKI is still one of the best technologies for electronic authentication in an open network, but it is used only in limited areas: for user authentications in closed networks and for server authentications within network security infrastructure like SSL/TLS. The difference between expectation and reality of PKI usage is due to the evolution of the Internet along with the global adoption of new authentication policies under the Internet governance in the early 2000s. The new Internet governance based on the cooperation between multi-stakeholders is changing the way in which a government should act with regard to its technological policies. This paper analyzes different PKI policy approaches in the United States and Korea from the perspective of path-dependence theory. Their different policy results show evidence of the rise of the Internet governance, and may have important implications for policy-makers in the current global Internet society.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.36-44
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• 2010

When multi-user MIMO (Multiple-Input Multiple-Output) systems utilize a sum-rate maximization (SRM) scheduler, the throughput of the systems can be enhanced. However, fairness problems may arise because users located near cell edge or experiencing poor channel conditions are less likely to be selected by the SRM scheduler. In this paper, a weighted sum-rate maximization (WSRM) scheduler is used to enhance the fairness performance of the MIMO systems. Closed-form expressions for the optimal transmit power allocation of WSRM and corresponding weighted sum-rate (WSR) are derived in the 6-sector collaborative transmission system. Using the derived results, we propose an algorithm which searches the optimal power allocation for WSRM in the 3-sector collaborative transmission system. Based on the derived closed-form expressions and the proposed algorithm, we perform computer simulations to compare performance of the WSRM scheduler and the SRM scheduler with respect to the sum-rate and the log-sum-of-average rates. We further verify that the WSRM scheduler efficiently improves fairness performance by showing the enhanced performance of average transmission rates in low percentile region.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.342-354
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• 2014

This paper deals with digital watermarking methods to protect ownership of image with targeting the ultra-high multi-view or free-view image service in which an arbitrary viewpoint image should be rendered at the user side. The main purpose of it is not to propose a superior method to the previous methods but to show how difficult to construct a watermarking scheme to overcome the viewpoint translation attack. Therefore we target the images with various attacks including viewpoint translation. This paper first shows how high the error rate of the extracted watermark data from viewpoint-translated image by basic schemes of the method using 2DDCT(2D discrete cosine transform) and the one using 2DDWT(2D discrete wavelet transform), which are for 2D image. Because the difficulty in watermarking for the viewpoint-translated image comes from the fact that we don't know the translated viewpoint, we propose a scheme to find the translated viewpoint, which uses the image and the corresponding depth information at the original viewpoint. This method is used to construct the two non-blind watermarking methods to be proposed. They are used to show that recovery of the viewpoint affect a great deal of the error rate of the extracted watermark. Also by comparing the performances of the proposed methods and the previous ones, we show that the proposed ones are better in invisibility and robustness, even if they are non-blind.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.684-690
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• 2010

Recently, the NG(Next Generation) system is studied for supporting convergence of various services and multi mode of single terminal. And a demand of user for taking the various services is getting increased, for supporting these services, many systems being able to transmit a large message have been appeared. In the NG system, it has to be supporting the CDMA and WCDMA besides the tele communication systems using OFDM method with single terminal An intergrated system can be improved with adopting of SoC technique. For adopting SoC technique on the intergrated terminal, we have to solve the non linear problem of HPA(High Power Amplifier). Nonlinear characteristic of HPA distorts both amplitude and phase of transmit signal, this distortion cause deep adjacent channel interference. We adopt a polynomial pre-distortion technique for this problem. In this paper, a noble modem design for NG mobile communication service and a method using polynomial pre-distorter with PAPR technique for counterbalancing nonlinear characteristic of the HPA are proposed.

• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.74-82
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• 2016

In this paper, a new automatic speech recognition (ASR) was proposed where ultrasonic doppler signals were used, instead of conventional speech signals. The proposed method has the advantages over the conventional speech/non-speech-based ASR including robustness against acoustic noises and user comfortability associated with usage of the non-contact sensor. In the method proposed herein, 40 kHz ultrasonic signal was radiated toward to the mouth and the reflected ultrasonic signals were then received. Frequency shift caused by the doppler effects was used to implement ASR. The proposed method employed multi-channel ultrasonic signals acquired from the various locations, which is different from the previous method where single channel ultrasonic signal was employed. The PCA(Principal Component Analysis) coefficients were used as the features of ASR in which hidden markov model (HMM) with left-right model was adopted. To verify the feasibility of the proposed ASR, the speech recognition experiment was carried out the 60 Korean isolated words obtained from the six speakers. Moreover, the experiment results showed that the overall word recognition rates were comparable with the conventional speech-based ASR methods and the performance of the proposed method was superior to the conventional signal channel ASR method. Especially, the average recognition rate of 90 % was maintained under the noise environments.

• The Journal of Society for e-Business Studies
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• v.18 no.2
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• pp.205-222
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• 2013

One of the recent important issues in IT fields is the convergence. It had been simply focused on functional convergence of technologyies. However the convergence in terms of businesses or services also has been made in recent years. The convergence between broadcasting and telecommunication industries can be possible because the e-transformation of broadcasting industry based on digital technology such as multimedia and multi-channel, can be combined with the high speed telecommunication network. It is giving a birth of various convergence services such as IPTV. IPTV is a kind of new service that is combined with the convergence of network, contents, and device. Nevertheless the controversy about the scope and the value of this new convergence service has constantly been raised; for example, what is the difference between IPTV and Internet TV? or what are the benefits that customers can have? This study measured the expectation level and the cognitive level of users before and after using the service and analyzed the gap between the importance and the satisfaction of the service. From this study, we proposed the priority of each function by analysing Importance-Performance Analysis(IPA) method to suggest required functions of IPTV service based on N-Screen technology. This study will identify the gap of awareness level between service providers and end users for the functions of broadcasting and telecommunications convergence service and suggest a solution enhancing user satisfaction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2307-2314
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• 2015

This paper focuses on the generation algorithm of BeiDou pseudorange correction (PRC) and simulation based performance verification for design of Differential Global Navigation Satellite System (DGNSS) reference station and integrity monitor (RSIM) in order to prepare for recapitalization of DGNSS. First of all, it discusses the International standard on DGNSS RSIM, based on the interface control document (ICD) for BeiDou, estimates the satellite position using satellite clock offset and user receiver clock offset, and the system time offset between Global Positioning System (GPS) and BeiDou. Using the performance verification platform interfaced with GNSS (GPS/BeiDou) simulator, it calculates the BeiDou pseudorange corrections , compares the results of position accuracy with GPS/DGPS. As the test results, this paper verified to meet the performance of position accuracy for DGNSS RSIM operation required on Radio Technical Commission for Maritime Services (RTCM) standard.

• Journal of KIISE:Databases
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• v.41 no.4
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• pp.249-255
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• 2014

Copy number variations(CNVs) are a recently recognized class of human structural variations and are associated with a variety of human diseases, including cancer. To find important cancer genes, researchers identify novel CNVs in patients with a particular cancer and analyze large amounts of genomic and clinical data. We present a tool called CNVDAT which is able to detect CNVs from NGS data and systematically analyze the genomic and clinical data associated with variations. CNVDAT consists of two modules, CNV Detection Engine and Sequence Analyser. CNV Detection Engine extracts CNVs by using the multi-resolution system of scale-space filtering, enabling the detection of the types and the exact locations of CNVs of all sizes even when the coverage level of read data is low. Sequence Analyser is a user-friendly program to view and compare variation regions between tumor and matched normal samples. It also provides a complete analysis function of refGene and OMIM data and makes it possible to discover CNV-gene-phenotype relationships. CNVDAT source code is freely available from http://dblab.hallym.ac.kr/CNVDAT/.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.49-61
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• 2011

In recent, library is considered as an integrated knowledge convergence center that can respond to various requests about information service of users. Therefor it is necessary to establish a novel information system based on information communications technologies of the era. In other words, it is currently required to develop mobile information service available in portable devices such as smart phones or tablet PCs, and to establish information system reflecting cloud computing, SaaS, Annotation, and Library 2.0 etc. In this paper we design and implement a library information system using collective intelligence and cloud computing. This information system can be adapted for the varieties of mobile service paradigm and abruptly increasing amount of electronic materials. Advantages of this concept model are resource sharing, multi-tenant supporting, configuration, and meta-data supporting etc. In addition it can offer software on-demand type user services. In order to test the performance of our system, we perform an effectiveness analysis and TTA authentication test. The average response time corresponding to variance of data reveals 0.692 seconds which is very good performance in timing effectiveness point of view. And we detect maturity level-3 or 4 authentication in TTA tests such as SaaS maturity, performance, and application programs.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.51-59
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• 2010

We developed an analysis software that automatically detects incoming isotopes for multi-purpose gamma-ray detectors. The software is divided into three major parts; Network Interface Module (NIM), Spectrum Analysis Module (SAM), and Graphic User Interface Module (GUIM). The main part is SAM that extracts peak information of energy spectrum from the collected data through network and identifies the isotopes by comparing the peaks with pre-calibrated libraries. The proposed peak detection algorithm was utilized to construct libraries of standard isotopes with two peaks and to identify the unknown isotope with the constructed libraries. We tested the software by using GammaPro1410 detector developed by NuCare Medical Systems. The results showed that NIM performed 200K counts per seconds and the most isotopes tested were correctly recognized within 1% error range when only a single unknown isotope was used for detection test. The software is expected to be used for radiation monitoring in various applications such as hospitals, power plants, and research facilities etc.