• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.944-947
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• 2002

We implemented a cryptoprocessor with a on-the-fly key scheduler which performs forward key scheduling for encryption and reverse key scheduling for decryption. This scheduler makes the fast generation of the key value and eliminates the memory for software key scheduler. The 128-bit Rijndael processor is implemented based on the proposed architecture using Verilog-HDL and targeted to Xilinx XCV1000E FPGA device. As a result, the 128-bit Rijndael operates at 38.8MHz with on-the-fly key scheduler and consumes 11 cycles for encryption and decryption resulting in a throughput of 451.5Mbps

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.11
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• pp.39-46
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• 1997

In this paper, we propose an area-efficient architecture of a reed-solomon (RS) decoder/encoder for digital VCRs. The new architecture of the decoder/encoder targeted to reduce the circit size and decoding latency has the following two features. First, area-efficeincy has been significantly improved by sharing a functional block for encoding, modified syndrome computation, and erasure locator polynomial evaluation. Second, modified euclid's algorithms has been implemented by using a new architecture. Experimental results have showed that the decoder/encoder designed by using the proposed method has been implemented with 25% smaller sie over straight forware implementation based on the conventional method [1] and the decoding latency has been reduced.

• Electronics and Telecommunications Trends
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• v.35 no.4
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• pp.149-157
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• 2020

Security threats in supply-chains can be targeted at all the users who use products related to these supply-chains as well as at single equipment or individuals. This implies that these security threats can cause nationwide economic and social damages. In particular, it is true that hardware security threat analysis technology in supply-chains has significant technical barriers due to the lack of software knowledge as well as the need to study and understand undisclosed hardware designs. In this paper, we discuss the future direction of studies by introducing basic concepts and attack cases, along with domestic and foreign technology trends related to supply-chain security technology.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.394-397
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• 2002

A design study of phase detectors for the 2.5 Gb/s CDR circuit using a standard 0.18-${\mu}{\textrm}{m}$ CMOS process has been performed. The targeted CDR is based on the phase-locked loop and thus it consists of a phase detector, a charge pump, a LPF, and a VCO. For high frequency operation of 2.5 Gb/s, phase detector and charge pump, which accurately compare phase errors to reduce clock jitter, are critical for designing a reliable CDR circuit. As a phase detector, the Hogge phase detector is selected but two transistors are added to improve the performance of the D-F/F. The charge pump was also designed to be placed indirectly input and output.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.206-212
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• 2015

This paper introduces new wideband antenna-filter-antenna (AFA) uniform arrays that can be utilized as frequency selective surfaces (FSS) with low loss and sharp roll-off response, which are highly desirable characteristics for millimeter wave applications. The design adopts a simple 3-layer single polarization structure consisting of two patch antennas and a resonator. Both simulations and measurements are used to characterize the performances of the proposed design. Overall results show 18.5% 10-dB bandwidth. For the targeted band the insertion loss is less than 0.2 dB. Possible applications include quasi-optical amps, grid mixers and radomes for aircraft radar antennas.

• International Journal of Human Ecology
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• v.14 no.2
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• pp.1-13
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• 2013

This study examined the factors that influenced school adaptation by adolescents from non-military families and military families; subsequently, our research targeted 387 middle school children located in Chungnam province. Questionnaires were used and data analysis was conducted by t-tests and multiple regression analysis. The results were as follows: First, adolescents from non-military families perceived higher levels of attachment to fathers and self-esteem than adolescents from military families. However, the stress level for adolescents from military families was higher than adolescents from non-military families and adolescents from non-military families adapted better to school than adolescents from military families. Secondly, family dynamic, attachment to fathers, and stress influenced school adaptation by adolescents of non-military families and family dynamic and the attachment to friends influenced the adaptation to school by adolescents from military families.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.129-139
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• 2007

In this paper, attitude control laws for simultaneous pointing of multiple spacecrafts are considered under a formation flying scenario. The basic approach lies in adaptive feedback gains using relative attitude information or maneuver time approximation for coordinated attitude control. Each control law is targeted to balancing mean motion or to correcting system response to the slowest satellite. The control gain adaptation is constructed by two approaches. The first one is using variable damping gain to manipulate speed of a fast system response, and the second one uses alternate natural frequency of the system under control. The validity and stability of the proposed approaches are examined analytically and tested through numerical simulations.

• Biomedical Science Letters
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• v.21 no.4
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• pp.165-171
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• 2015

Microbial pathogens are responsible for most of the rapidly-spreading deadly infectious diseases against humans. Thus, there is an urgent need for efficient and rapid detection methods for infectious microorganisms. The detection methods should not only be targeted and specific, but they have to be encompassing of potential changes of the pathogen as it evolves and mutates quickly during an epidemic or pandemic. The existing diagnostics such as the antibody-based ELISA immunoassay and PCR methods are too selective and narrowly focused; they are insufficient to capture newly evolved mutant strains of the pathogen. Here, we introduce a fresh perspective on some new technologies, including aptamers and next generation sequencing for pathogen detection. These technologies are not in their infancy; they are reasonably mature and ready, and they hold great promise for unparalleled applications in pathogen detection.

• Biomedical Science Letters
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• v.21 no.4
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• pp.241-247
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• 2015

Lactate and ketone bodies are considered biological markers for ketosis and several inherited metabolic disorders. In the current study, the specific ratios of lactate and ketone bodies as analytical tools for differential diagnosis of various lactic acidosis were devised. The study included a protein precipitation step following tert-butyldimethylsilyl derivatisation. Total run time was approximately 30 min including sample preparation and GS/MS analysis. The limits of detection were below 0.1 pg/mL over the targeted 4 analytes. The calibration curve was linear over the concentration range of $0.001{\sim}250{\mu}g/mL$ for pyruvate, beta-hydroxybutyrate, and acetoacetate ($R^2$ > 0.99). Inter-day accuracy and precision were 87.7~94.8% with RSD of 2.5~5.7% at 2 levels. Absolute recoveries (%) of target analytes were 87.0~98.4%. The method was validated for the quantification of lactate and ketone bodies for differentiation of lactic acidosis.

• Korean Journal of Biological Psychiatry
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• v.23 no.3
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• pp.89-101
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• 2016

Transcranial magnetic stimulation (TMS) is a safe, noninvasive and useful technique for exploring brain function. Especially, for the study of cognition, the technique can modulate a cognitive performance if the targeted area is engaged, because TMS has an effect on cortical network. The effect of TMS can vary depending on the frequency, intensity, and timing of stimulation. In this paper, we review the studies with TMS targeting various regions for evaluation of cognitive function. Cognitive functions, such as attention, working memory, semantic decision, discrimination and social cognition can be improved or deteriorated according to TMS stimulation protocols. Furthermore, potential therapeutic applications of TMS, including therapy in a variety of illness and research into cortical localization, are discussed.