• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.389-390
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• 1996

The CCDs are widely used in astronomical observations either in direct imaging use or spectroscopic mode. However, the areas of available sensors are too small for large imaging format. One possibility to obtain large detection area is to assemble mosaics of CCD, and drive them simultaneously. Parallel driving of many CCDs together rules out the possibility of individual tuning; however, such optimisation is very important, when the ultimate low light level performance is required, particularly for new, or mixed devices. In this work, a new concept is explored for an entirely novel approach, where the drive waveforms are multiplexed and interleaved. This simultaneously reduces the number of leadout connections and permits individual optimisation efficiently. The digital controller can be designed within a single EPLD (Erasable Programmable Logic Device) chip produced by a CAD software package, where most of the digital controller circuits are integrated. This method can minimise the component. count., and improve the system efficiency greatly, based on earlier works by Han et a1. (1996, 1994). The system software has an open architecture to permit convenient modification by the user, to fit their specific purposes. Some variable system control parameters can be selected by a user with a wider range of choice. The digital controller design concept allows great flexibility of system parameters by the software, specifically for the compatibility to deal with any number of mixed CCDs, and in any format, within the practical limit.

• Knowledge Management Research
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• v.21 no.2
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• pp.77-100
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• 2020

This study conducted a qualitative study on 23 seniors over 55 years old to understand the digital behavior of seniors in the online education acceptance environment. Grounded Theory methodology was applied to the initial enrollment behavior, login behavior, and utilization behavior of online education program. Through the process of open coding, axis coding, and selective coding, the framework in the online education environment of the senior generation was finally derived. As a causal conditions for the senior generation to participate in the online education environment, goal orientation, relationship orientation, leisure orientation and external compulsory were derived, and shadow work appeared as the central phenomenon. Also, contextual conditions resulted in social change, physical and cognitive aging, and psychological atrophy. The intervening conditions included digital device acceptance, educational attitudes, environmental factors, and self-efficacy. Based on this, the action/interactions strategy formed a positive and negative attitude toward shadow work. As a result, positive response behavior, compromising behavior, and shadow work avoidance behavior were shown. It is hoped that this study will be reflected in future researches for the use of digital devices of the elderly and the expansion of online education participation and government policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3079-3085
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• 2014

This paper suggests a power level controllable frequency up-converter which is designed and fabricated using both the filtering technology consisted with only passive devices and a multi-level digital attenuator. The suggested frequency up-converter simultaneously realizes the low power consumption and the low cost model. Because of the possibility for controlling power levels, it is possible to use the suggested frequency up-converter for wide spectral range. According to the experimental results, the average gain value of 0.75dB is obtained for the bandwidth of 160MHz at the center frequency of 1,200MHz. Especially, it is confirmed that the power level can be controlled from 10 to -21.5dBm through the digital attenuator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1003-1010
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• 2006

The usage increase of digital contents required solution for protection technology and interoperability of system. MPEG(Moving Picture Experts Group) proposed MPEG-21 Multimedia Frameworks. MPEG-21 IPMP is standard that provides the means to enable digital item and rights information to be persistently managed and protected across networks and devices. In this paper, MPEG-21 IPMP based system to protect digital contents designed by four structures of license server, production server, consumption server, tool server. License server create rights information document using the XML-based REL about multimedia contents of users. Production server makes a digital item by packaging multimedia resource and metadata, which is combined by REL information and IPMP information of multimedia resource. Consumption server takes care of the functions of players that use digital item, and tool server was implement to transmit for missing tool that might occur in all procedures.

• Convergence Security Journal
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• v.23 no.1
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• pp.97-107
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• 2023

With the popularization of digital devices in the era of the 4th industrial revolution and the increase in cyber crimes targeting them, the importance of securing digital data evidence is emerging. However, the difficulty in securing digital data evidence is due to the use of anti-forensic techniques that increase analysis time or make it impossible, such as manipulation, deletion, and obfuscation of digital data. Such anti-forensic is defined as a series of actions to damage and block evidence in terms of digital forensics, and is classified into data destruction, data encryption, data concealment, and data tampering as anti-forensic techniques. Therefore, in this study, anti-forensic techniques are categorized into data concealment and deletion (obfuscation and encryption), investigate and analyze recent research trends, and suggest future anti-forensic research directions.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.329-335
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• 2010

Digital imaging detectors can use a variety of detection materials to convert X-ray radiation either to light or directly to electron charge. Many detectors such as amorphous silicon flat panels, CCDs, and CMOS photodiode arrays incorporate a scintillator screen to convert x-ray to light. The digital radiography systems based on semiconductor detectors, commonly referred to as flat panel detectors, are gaining popularity in the clinical & hospital. The X-ray detectors are described between a-Silicon based indirect type and a-Selenium based direct type. The DRS of detectors is used to convert the x-ray to electron hole pairs. Image processing is described by specific image features: Latitude compression, Contrast enhancement, Edge enhancement, Look up table, Noise suppression. The image features are tuned independently. The final enhancement result is a combination of all image features. The parameters are altered by using specific image features in the different several hospitals. The image in a radiological report consists of two image evaluation processes: Clinical image parameters and MTF is a descriptor of the spatial resolution of a digital imaging system. We used the edge test phantom and exposure procedure described in the IEC 61267 to obtain an edge spread function from which the MTF is calculated. We can compare image in the processing parameters to change between original and processed image data. The angle of the edge with respect to the axes of detector was varied in order to determine the MTF as a function of direction. Each MTF is integrated within the spatial resolution interval of 1.35-11.70 cycles/mm at the 50% MTF point. Each image enhancement parameters consists of edge, frequency, contrast, LUT, noise, sensitometry curve, threshold level, windows. The digital device is also shown to have good uniformity of MTF and image parameters across its modality. The measurements reported here represent a comprehensive evaluation of digital radiography system designed for use in the DRS. The results indicate that the parameter enables very good image quality in the digital radiography. Of course, the quality of image from a parameter is determined by other digital devices in addition to the proper clinical image.

• Korean Journal of Artificial Intelligence
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• v.11 no.2
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• pp.39-44
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• 2023

The creativity of thesis is that the significance of cyber security challenges in blockchain. The variety of enterprises, including those in the medical market, are the targets of cyberattacks. Hospitals and clinics are only two examples of medical facilities that are easy targets for cybercriminals, along with IoT-based medical devices like pacemakers. Cyberattacks in the medical field not only put patients' lives in danger but also have the potential to expose private and sensitive information. Reviewing and looking at the present and historical flaws and vulnerabilities in the blockchain-based IoT and medical institutions' equipment is crucial as they are sensitive, relevant, and of a medical character. This study aims to investigate recent and current weaknesses in medical equipment, of blockchain-based IoT, and institutions. Medical security systems are becoming increasingly crucial in blockchain-based IoT medical devices and digital adoption more broadly. It is gaining importance as a standalone medical device. Currently the use of software in medical market is growing exponentially and many countries have already set guidelines for quality control. The achievements of the thesis are medical equipment of blockchain-based IoT no longer exist in a vacuum, thanks to technical improvements and the emergence of electronic health records (EHRs). Increased EHR use among providers, as well as the demand for integration and connection technologies to improve clinical workflow, patient care solutions, and overall hospital operations, will fuel significant growth in the blockchain-based IoT market for linked medical devices. The need for blockchain technology and IoT-based medical device to enhance their health IT infrastructure and design and development techniques will only get louder in the future. Blockchain technology will be essential in the future of cybersecurity, because blockchain technology can be significantly improved with the cybersecurity adoption of IoT devices, i.e., via remote monitoring, reducing waiting time for emergency rooms, track assets, etc. This paper sheds the light on the benefits of the blockchain-based IoT market.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1421-1433
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• 2015

For an accurate analysis through the forensic of digital devices and computer, it is a very important validation of the reliability of digital forensic tools. To verify the reliability of the tool, it is necessary to research and development of the data set to be input to the tool. In many-used Windows operating system of the computer, there is a Window forensic artifacts associated with time and system behavior. In this paper, we developed a set of data in the Windows operating system to be able to analyze all of the two Windows artifacts and we conducted a test with published digital forensic tools. Therefore, the developed data set presents the use of the following method. First, artefacts education for growing ability can be analyzed acts standards. Secondly, the purpose of tool tests for verifying the reliability of digital forensics. Lastly, recyclability for new artifact analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.3
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• pp.1-10
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• 2013

Most of the current traffic signal controller use load switches to transmit high voltage power to the signal lamps. The direct transmission of high voltage power may cause a lot of problems like leakages of electric power, obstructions of pedestrian, environmental disfigurements. To overcome these problems, the development of digital type signal controller has been trying in the various methods. Digital communication between a master controller and signal lamps is the most important part to improve control performance in the digital type controller. A communication system for the digital signal controller was developed in this study. The system bases on CAN specification, includes ID structure for most peripheral devices like loops, signal lamps, push buttons, police switches. The operability of this system verified with a software based CAN simulation tool.

• Journal of The Korean Association of Information Education
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• v.19 no.2
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• pp.197-206
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• 2015

The dissemination of smart appliances, along with the development of the latest information and communication technology has an effect on society. Their application can be seen in the smart learning environment, by use of digital textbooks with smart devices in the classroom. Hence in this study, the 4L-ACC activity using digital textbooks was applied in the third grade social studies class to improve critical thinking and problem solving skills of elementary school students. This study compared and analyzed the impact in critical thinking and problem-solving skills using digital textbooks versus standard social studies classes. As a result, in social studies classes that used the 4L-ACC activity compared to common social studies classes, elementary student's problem understanding, critical thinking, problem resolution, reflective thinking, and all lower areas of critical thinking and problem-solving were improved. In conclusion, using digital textbooks enhance student's ability to think critically and problem solve. This should provide learners a more comprehensive learning experience and therefore be integrated into more education environment.