• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.1
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• pp.147-155
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• 2003

The diffusion of internet infrastructure and a fast increase of Population to use it is becoming a base of the service that can use various information, data and digital contents which were provided through off-line physically and used. Recently, the. techniques for copy deterrence and copyright protection have been important in e-commerce because various contents in digital form can be duplicated easily. The Access Control(AC) technique that only a user having the qualifications can access and use contents normally has been studied. The Conditional Access System(CAS) used in a satellite broadcasting md Digital Right Management System(DRMS) used for contents service are representative models of current commercialized access control. The CAS and DRM can be considered as an access control technique based on the payment based type(PBT). This paper describe the access control method of payment free type(PFT) suggested in ［5］ which are independent on the payment structure. And then we suggest a new access control method of payment free type which is more efficient than the previous one.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1103-1113
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• 2020

Hospitals store and manage personal and health information through the electronic medical record (EMR). However, vulnerabilities and threats are increasing with the provision of various services for information sharing in hospitals. Therefore, in this paper, we propose a model to prevent personal information leakage due to the transmission of patient information in EMR. A method for granting permission to securely receive and transmit patient information from hospitals where patient medical records are stored is proposed using OAuth authorization tokens. A protocol was proposed to enable secure information delivery by applying and delivering the record access restrictions desired by the patient to the OAuth Token. OAuth Delegation Token can be delivered by writing the authority, scope, and time of destruction to view patient information.This prevents the illegal collection of patient information and prevents the leakage of personal information that may occur during the delivery process.

• The Journal of the Acoustical Society of Korea
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• v.25 no.8
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• pp.356-361
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• 2006

We present the performance of differential space-time block decoders. which does not require the channel state information. We suggest the structure of the multiple blocks differential space time decoders. which does not require the channel state information, and analyze the Performances. In quasi-static flat fading channels. the Performance of multiple blocks differential detection (MD-STC) outperforms that of 2 blocks(D-STC) by 1.5dB. But in the time-selective fading channels due to Doppler frequency $(f_d)$, the performance of MD-STC degrades as the vehicular speed is greater than 200km/hr in 802.16e systems, where the data transmission rate is 144kbps.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.22-28
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• 2007

Spectrum spreading, in its general form, can be conceived as an artificial expansion of the signal bandwidth with respect to the minimum Nyquist band required to transmit the desired information. Spreading can be functional to several objectives, including resilience to interference and jammers and reduction of power spectral density levels. In the paper, signal spreading is manly used for increasing the received energy, thus satisfying link budget constraints, for terminals with low aperture antennas, without increasing the transmitted EIRP. As a matter of fact, in many mobile scenarios, even when MODCOD configurations with very low spectral efficiency (i.e. QPSK-1/4) in DVB-S2 standard, are used, the link budget cannot be closed. Spectrum spreading has been recently proposed as a technique to improve system performance without introducing additional MODCOD configurations under the constraint of fixed power spectrum density level at the transmitter side. To this aim, the design of spectrum spreading techniques shall keep into consideration requirements such as spectrum mask, physical layer performance, link budget, hardware reuse, robustness, complexity, and backward compliance with existing commercial equipments. The proposed implementation allows to fully reuse the standard DVB-S2 circuitry and is inserted as an 'inner layer' in the standard DVB-S2 chain.

• Korean Journal of Remote Sensing
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• v.34 no.6_3
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• pp.1415-1425
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• 2018

Kompsat-5 is the first Earth Observation Satellite which is equipped with an SAR in Korea. SAR images are generated by receiving signals reflected from an object by microwaves emitted from a SAR antenna. Because the wavelengths of microwaves are longer than the size of particles in the atmosphere, it can penetrate clouds and fog, and high-resolution images can be obtained without distinction between day and night. However, there is no color information in SAR images. To overcome these limitations of SAR images, colorization of SAR images using Cycle GAN, a deep learning model developed for domain translation, was conducted. Training of Cycle GAN is unstable due to the unsupervised learning based on unpaired dataset. Therefore, we proposed MS Cycle GAN applying multi-scale discriminator to solve the training instability of Cycle GAN and to improve the performance of colorization in this paper. To compare colorization performance of MS Cycle GAN and Cycle GAN, generated images by both models were compared qualitatively and quantitatively. Training Cycle GAN with multi-scale discriminator shows the losses of generators and discriminators are significantly reduced compared to the conventional Cycle GAN, and we identified that generated images by MS Cycle GAN are well-matched with the characteristics of regions such as leaves, rivers, and land.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.129-137
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• 2009

While the broadband network and multimedia technologies have been developing, the commercial market of digital contents also has been widely spreading with recently starting IPTV. As the IPTV services are getting to be generalized and popularized, the contents protection and authentication system tends to draw more attentions. So we need a system that can protect contents and allow only authenticated person to use right service by controling user authority and using content encryption. Until now, the conventional protection and authentication system is taking advantages of merits both in CAS and DRM. But the weak point of this system are in high costs, complexity and using HW. For resolving these problems, in this paper, we proposed IPTV contents protection and authentication system using OTP. When we transmit the content encrypted by OTP key using contents delivery technology, we operate XOR with contents using another settop-box's OTP key which was transmitted from distribution server. And contents are reconstructed and transmitted to the settop-box, In the end, downloaded content are encrypted by OTP key and are superior in content protection when contents redistribution. Since OTP use double-authentication elements in encryption process, this method is excellent in content protection. And it is very effective in cost aspect because it could be implemented by SW program. Another benefit is that we can shorten the development time period. In this paper, we propose and find its possibility as a new content protection and authentication method suitable for IPTV services.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.38-46
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• 2011

3D motion analysis system which is currently widely used for walking analysis has limitations due to both necessity of wide space for many cameras for measurement, high cost, and complicated preparation procedure, which results in low accessability in use and application for clinical diagnosis. To resolve this problem, we developed 3-dimensional wireless ambulatory measurement system based on inertial sensor which can be easily applicable for clinical diagnosis for lower extremity deformity and developed system was evaluated by applying for 10 elderly people with diabetes mellitus. Developed system was composed of wireless ambulatory measurement module that consists of inertial measurement unit (IMU) which measures the gait characteristics, microcontroller which collects and precesses the inertial data, bluetooth device which transfers the measured data to PC and Window's application for storing and processing and analyzing received data. This system will utilize not only to measure lower extremity (foot) problem conveniently in clinical medicine but also to analyze 3D motion of human in other areas as sports science, rehabilitation.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.37-43
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• 2014

The ground station which operates the LEO satellite performs monitoring state of health of the satellite, sending the commands for the imaging mission of receiving the images during about 10 minutes of contact time. To finish the planned procedure in limited contact time, specific level of autonomy is applied in the satellite and the ground system. For example, the attitude and orbit control logic has high level of autonomy because it must be operated alone for long period without operator intervention. On the other hand, the fault management logic has relatively low level of autonomy because of that failure detection and safing operation are performed on-board, whereas failure identification and recovery are on-ground operation. The level of autonomy of the satellite affects also the ground operation. The command set for mission operation is generated by ground system. If the satellite has higher level of autonomy, some of operation currently done on-ground can be performed on-board, so the ground operation can be simplified. In this paper, we discuss the level of autonomy and propose a concept for improving the level of autonomy of an LEO satellite.

• KIISE Transactions on Computing Practices
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• v.24 no.1
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• pp.33-39
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• 2018

For the integration test in the current field of defense simulation, each actual equipment and simulator's logging information is automated. Although the event of the integrated test system is written in the test log, it is not automated, and relies on the operator's handwriting or file creation, resulting in ineffective aspects such as low-quality record content and repetition of the same content. In this study, we propose the automatic test report recording program that solves these problems. Automatic test report recording program uses framework-based technology to receive information from the test control computer and user to record a log of the test log. Automatic test report recording program allows the user to record the repeated test content in a stable manner. Additionally, even if the number of test operators is limited, the efficiency is improved so that we can fucus on the integration test.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.1
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• pp.31-38
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• 2011

With the increasing demand for high-speed transmission systems, adaptive equalizers have been widely used in receivers to overcome the limited bandwidth of channels. In order to reduce the cost for testing high-speed receiver chips, on-chip eye-opening monitoring (EOM) technique which measures the eye-opening of data waveform inside the chip can be employed. In this paper, a 10-Gb/s adaptive 2-tap look-ahead decision feedback equalizer (DFE) with EOM function is proposed. The proposed EOM circuit can be applied to look-ahead DFEs while existing EOM techniques cannot. The magnitudes of the post-cursors are measured by monitoring the eye of received signal, and coefficients of DFE are calculated using them by proposed adaptation algorithm. The circuit designed in 90nm CMOS technology and the algorithm are verified with post-layout simulation. The DFE core occupies $110{\times}95{\mu}m^2$ and consumes 11mW in 1.2V supply voltage.