• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.37-42
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• 2004

In order to monitor the impact locations in smart structures, multipoint ultrasonic sensors are to be employed. In this study, a multiplexing demodulator with wide dynamic range was proposed to detect the impact locations using FBG sensors, and a stabilization controlling system was also developed for the maintenance of maximum sensitivity of sensors. Two FBG sensors were attached on the bottom side of the aluminum beam specimen and low velocity impact tests were performed to detect the one-dimensional impact locations. As a result, multiplexed in-line FBG sensors could detect the moment of impact precisely, and found the impact locations with the average location error below 0.58mm.

• Journal of Life Science
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• v.24 no.7
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• pp.762-768
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• 2014

Diet exerts a major stress on the body and may affect gene expression and physiological functions. Understanding of cellular responses during starvation is necessary in developing strategies to reduce damage caused by diet. In this study, we isolated 10 genes (Comt, RGN, Scd1, Temt, Idi1, Fabp5, Car3, Cyp2c70, Pinx1, and Poldip3) that are down-regulated in starvation and are closely related to liver metabolism. Water supply during starvation had no effect on the induction of apoptosis, autophagy, and ERQC. The genes down-regulated by starvation were associated with many related pathways rather than limited to the liver homeostasis pathway. Water supply during starvation is important. However, maintaining NaCl homeostasis is more important. The results are thought to be closely related to gender-specific metabolism in starvation and NaCl.

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.85-95
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• 1995

Radiation measuring system using wireless communication method with single channel has been diveloped and tested. In this system, radiation signals from GM tube are transformed into digital pulses in pulse processing circuit and modulated in FSK (frequency shift keying) circuit for digital communication and then wirelessly transmitted to a receiving unit. The digital pulses received are then demodulated in FSK circuit and converted into radiation dose/dose rate in the data acquisition unit to display on the screen of a personal computer. The performance of this system was evaluated by using both a pulse generator and a standard radiation source(Cs-137). In both cases, digital pulses with 5V were observed in pulse processing circuit without distortion of their shape through wireless communication system. The experimental results of radiation measurement by this system after several test-irradiation of GM detector to a standard radiation source(Cs-137), showed good agreement with irradiation dose rate within 10% difference, and proved that this system could be effectively utillized as radiation measuring instrument. It is expected that this wireless radiation measuring system developed for the first time in Korea, can be used as a radiation monitor as well as a personal dosimeter if we can further improve this system to adopt wireless multichannel communication system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.678-687
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• 2003

8SQAM(8-state Superposed Quadrature Amplitude Modulation) being a new modem technique for use in power and bandwidth limited digital communication system generates output signals which have a mか and continuous phase transition and a reduced envelope fluctuation by keeping correlation between amplitudes and phases of two subsequent symbols. Also, 8SQAM signal is free of inter-symbol interference(ISI), and has a compact power spectrum. Accordingly 8SQAM, as compared with a conventional 8PSK, is influenced a little by inter-modulation(IM), inter-symbol interference(ISI) and adjacent channel interference(ACI) in a nonlinearly amplified multi-channel(SCPC-FDMA) environment. In this paper, the performance of 8SQAM system in a nonlinearly amplified multi-channel interference environment is analyzed via computer simulation The simulation result shows that 8SQAM outperforms 8PSK with roll-off value of $\alpha$ = 0.3 by 2.7dB in CNR to maintain BER=1$\times$10$^{-4}$ when input back-off(IBO) of HPA is 1dB and channel space is 41.7% of the data bit rate(i.e., spectral efficiency = 2.40b/s/Hz).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1563-1570
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• 1999

This paper relates to the soft decision method with erasure technique in digital terrestrial television broadcasting system. The proposed decoder use the CSI derived from using the pilots in receiver. The active real(I) and imaginary(Q) data are transferred to the branch metric calculation block that decides the Euclidean distance for the soft decision decoding and also the estimated CSI values are transferred to the same block. After calculating the Euclidean distance for the soft decision decoding, the Euclidean distance of branch metric is multiplied by CSI. To do so, new branch metric values that consider each carrier state information are obtained. We simulated this method in better performance of about 0.15dB to 0.17dB and 2.2dB to 2.9dB in Rayleigh channel than that of the conventional soft decision Viterbi decoding with or without bit interleaver where the constellation is QPSK, 16-QAM and 64-QAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.187-198
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• 2004

In this paper, we analyze the performance of BPM (Bi-Phase Modulation) UWB (Ultra Wide Band) multiple access system using PN (Pseudo Noise) code based time hopping sequence in indoor wireless channels. In particular, we compare BPM UWB multiple access system with PPM (Pulse Position Modulation) UWB multiple access system in terms of signalling and demodulation schemes. Moreover, we analytically evaluate the performance of these UWB systems by deriving the bit error rate expressions under the assumption that pulse energy and data transmission rate are identical for both systems. Simulation results in additive white Gaussian noise and realistic indoor multipath wireless channels show that the performance of BPM scheme is approximately 1 dB better than that of PPM scheme. However, the performance discrepancy becomes negligible as the number of users increases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.669-677
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• 2003

A new Modem technique - 8SQAM(8-state Superposed Quadrature Amplitude Modulation) - for use in power and bandwidth limited digital communication system is proposed. 8SQAM is free of inter-symbol interference(ISI) and generates output signals which have a smooth and continuous phase transition and a reduced envelope fluctuation by keeping correlation between amplitudes and phases of two subsequent symbols. Accordingly, 8SQAM, as compared with a conventional 8PSK, is influenced a little by ISI and inter-modulation(IM) caused by nonlinear distortions. In this paper, the performance of the 8SQAM system, in a nonlinearly amplified channel impaired by additive white Gaussian noise(AWGN), ISI and IM, is analyzed via computer simulation. The simulation result shows that 8SQAM outperforms 8PSK with roll-off value of $\alpha$=0.25 by 2.5dB in CNR to maintain BER=1$\times$10$^{-4}$ when input back-off(IBO) of HPA is 3dB.

• Journal of Digital Contents Society
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• v.7 no.3
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• pp.147-151
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• 2006

In recent years, the Internation Standard ISO/IEC 18000-6 is announced and a new scheme of Type C is added to conventional standard. Among the RFID systems the ISO/IEC 18000-6 standard is the most interesting to companies due to its potential market growth. The operating frequency is between 860-960 MHz, and three kinds of RFID system are included in the standard, i.e. type A, B and C. In this paper, we implemented the data frame of type C with baseband coding using VHDL. The data frame is encoded based on Miller code and FM0. We showed the implementation results with waveforms. The data frame was proved that it is properly implemented by the experiment of transmission and receiving operation.

• Journal of Life Science
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• v.23 no.7
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• pp.955-961
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• 2013

Genetic engineering, which was started by the E. coli gene manipulation, has led to rapid development in all area of life sciences. Recently, genetic engineering, which is an insertion or a removal technique of a specific gene on chromosomes, has been established and is usefully available in the applied life sciences including medicine and agriculture. In this review, we briefly explain pest management focusing on Release of Insects carrying a Dominant Lethal (RIDL) that is a highly economic and environment-friendly method of biological pest control. Although at present RIDL confronts many difficulties in applying directly in fields, it will be one of the best methods for the pest management in the near future without pesticides and disturbing ecosystem by the continued development of genetic engineering. However, these powerful techniques must be considered with great care to avoid harm to ecosystem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.528-537
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• 2008

This paper proposes a dynamic job distribution algorithm in a hybrid NoC structure which can improve system network performance by reducing deadlock and packet drop rate for various multimedia applications. The proposed job distribution algorithm schedules every job to the sub-cluster where packet drop rate can be minimized for each multimedia application program. The proposed Job distribution algorithm and network topology targets multimedia applications frequently used in modern embedded systems, such as MPEG4 and MP3 decoder, GPS positioning system, and OFDM demodulator. Experimental results show that packet drop rate was reduced by about 13.0%, and chip area was increased by about 2.7% compared to the APSRA algorithm. When compared to the XY algorithm popularly used for benchmarking, the packet drop rate was reduced by about 23.9%, while chip area was increased by about 3.0%.