• Journal of Digital Contents Society
• /
• v.6 no.2
• /
• pp.101-106
• /
• 2005

In this paper, performance evaluation of mobile access layer for multiple-input multiple-output (MIMO) MultiCarrier(MC)/CDMA 16 QAM system is considered to mitigate multiple access interference and enhance system channel capacity in Rayleigh wireless fading channel. Traditionally, multi-path is viewed as an undesirable feature of wireless communications. Therefore, diversity and adaptive array schemes are proposed to mitigate its effects. Recently, to increase the spectrum efficiency and the link reliability, MIMO schemes is devised to exploit multi-path in a scattering wireless channel. In particular, the channel capacity of MIMO-MC/CDMA 16 QAM system is evaluated according to Eb/No, Mc, p. From the results, in order to improve the channel capacity, the signals at various elements must be uncorrelated. And if the paths are correlated due to inappropriate spacing or mutual coupling effects, the channel capacity of MIMO-MC/CDMA 16 QAM system becomes substantially smaller.

• Journal of Digital Contents Society
• /
• v.6 no.3
• /
• pp.137-142
• /
• 2005

CDMA scheme has received a great deal of attenttion as a multiple-access method for future mobile networks. Its main advantage: are higher radio capacity and the capacity of flexible data tranmission. And CDMA scheme is a key technology in the proposals submitted to the ITU on next generation multimedia system with integrated services, namely real-time voice services and non real-time data services. In this paper, capacity evaluation of multiple-input multiple-output(MIMO) Multi-Carrier(MC)/CDMA system is considered to mitigate multiple access interference, partial-band interference and enhance system channel capacity in wireless channel. Recently, to increase the spectrum efficiency and the link reliability, MIMO-MC/CDMA scheme is devised to exploit multi-path in a scattering wireless channel. In particular, the channel capacity of MIMO-MC/CDMA system is evaluated according to Eb/No. Mc, p and B. From the results, in order to inappropriate spacing and the signals are frequency overlapped by partial band interference, the channel capacity of MIMO-MC/CDMA system becomes substantially smaller.

• Nuclear Engineering and Technology
• /
• v.41 no.7
• /
• pp.945-952
• /
• 2009

The Three Mile Island Unit 2 (TMI-2) accident provides unique full scale data, thus providing opportunities to check the capability of codes to model overall plant behavior and to perform a spectrum of sensitivity and uncertainty calculations. As part of the TMI-2 analysis benchmark exercise sponsored by the Organization for Economic Cooperation and Development Nuclear Energy Agency (OECD NEA), several member countries are continuing to improve their system analysis codes using the TMI-2 data. The Republic of Korea joined this benchmark exercise in November 2005. Seoul National University has analyzed the TMI-2 accident as well as the currently proposed alternative scenario along with a sensitivity study using the Modular Accident Analysis Program Version 4.03 (MAAP4.03) code in collaboration with the Korea Hydro and Nuclear Power Company. Two input files are required to simulate the TMI-2 accident with MAAP4: the parameter file and an input deck. The user inputs various parameters, such as volumes or masses, for each component. The parameter file contains the information on TMI-2 relevant to the plant geometry, system performance, controls, and initial conditions used to perform these benchmark calculations. The input deck defines the operator actions and boundary conditions during the course of the accident. The TMI-2 accident analysis provided good estimates of the accident output data compared with the OECD TMI-2 standard reference. The alternative scenario has proposed the initial event as a loss of main feed water and a small break on the hot leg. Analysis is in progress along with a sensitivity study concerning the break size and elevation.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.43 no.5 s.311
• /
• pp.48-56
• /
• 2006

In this paper, we proposed the high quality audio watermarking algorithm using MDCT/IMDCT (Modified DCT/Inverse Modified DCT) with psychoacoustic model. Generally, a digital audio watermark is embedding the frequency domain after frequency transform of the digital audio data but the digital audio quality is affected by watermarking. In our scheme, the digital audio data is spread with PN((Pseudo Noise) code and then audio watermark is embedded in MDCT processing that refers psychoacoustic model. In MDCT processing, according to the shape of filter bank output, the block switching selects a window sequence that has 256, 1,024 or 2,048 points interval for high quality audio. The author confirm that when watermark weight ${\alpha}$ is 2.5 below, the detection ratio of watermark is a satisfied to SDMI's(Secure Digital Music Initiative) recommendation 50% above and SM is $50{\sim}68dB$ range with mainly 4 kind of attacks(Compression, Cropping, FFT and Echo).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.1121-1124
• /
• 2015

In this paper, we propose and demonstrate an optimal design of wideband pulsed gamma-ray detectors. Pulsed gamma-ray detectors are designed to operate in a dose rate of $1{\times}10^6{\sim}1{\times}10^8rad(Si)/s$. The input parameter was derived based on the energy ratio of pulse gamma-ray spectrum and the time of the energy. The sensor output current was calculated based on the dose rate control circuit. Using the N-type Epi Wafer, the optimum condition detection sensor was designed based on TCAD. The simulation results show that the optimal Epi layer thickness is 45um when applied voltage 3.3V. The doping concentrations are as follows : N-type is an Arsenic as $1{\times}10^{19}/cm^3$, P-type is a Boron as $1{\times}10^{19}/cm^3$ and Epi layer is Phosphorus as $3.4{\times}10^{12}/cm^3$. Pulse gamma-ray detector diameter is the 1.3mm.

• 대한공업교육학회지
• /
• v.31 no.1
• /
• pp.185-199
• /
• 2006

In this paper, to detect lateral direction sound pressure fiber optic sensor using Fabry-Perot interferometeric sensor array was fabricated and experimented. This parallel sensor array composed of one light source and the light split into each sensor using directional coupler and to see the output signal the array system do not need any digital signal processor. As a lateral direction sound source arbitrary sound frequency of 100Hz, 200Hz, and 655Hz using by nondirectional speaker were applied to the array sensor which installed on $60cm{\times}60cm{\times}60cm$ latticed structure. The detected signals from the two sensors were analyzed in the time and frequency domains. It was confirmed that the suggested sensor array detected applied sound source well but there were a little amplitude differences in between the sensors. Because the sensor supported simply at both ends theoretical analysis was performed and its solution was suggested. To compare the theoretical and experimental results arbitrary sound frequency of 2kHz was applied to the sensor array. It shows that experimental results was good agreement with theoretical results.

• Journal of Acupuncture Research
• /
• v.27 no.5
• /
• pp.51-58
• /
• 2010

Objectives : The purpose of this study is to assess the effect of laser acupuncture at $HT_7$ for reducing mental stress using power spectrum analysis of the heart rate variability. Methods : 36 healthy volunteers(control group: 18, treatment group: 18) participated in this study. After instrumentation and 5-minute rest period, 5-minute metal stress by operation was provided. HRV was recorded before and after the mental stress(1st, 2nd HRV). After 2nd HRV recording, the control group rested for 15 minutes without any treatments. Participants in the treatment group received laser acupuncture to $HT_7$ unilaterally and rested for 15minutes. Points were irradiated for 60seconds, and the intensity was 1.8J(output 20%). And then 3rd HRV was recorded. Results : In simple rest group, LF norm showed a significant change after mental stress. In laser acupuncture group, LF norm, HF norm, LF, HF and LF/HF ratio showed a significant change after mental stress. But there were no significant difference between two groups(ANCOVA test, p>0.05). In laser acupuncture group, LF norm, HF norm, HF and LF/HF ratio showed a significant change after laser acupuncture treatment. And there were significant differences between two groups(p<0.05). Conclusions : This study suggests that laser acupuncture at $HT_7$ can regulate and prevent the alternation of autonomic nervous system due to mental stress.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.5
• /
• pp.294-300
• /
• 2005

Generally, traditional approaches to track the target position are to estimate ranges and bearings by 2-D MUSIC (MUltiple 519na1 Classification) method. and to associate estimates of 2-D MUSIC made at different time points with the right targets by JPDA (Joint Probabilistic Data Association) filter in the near field. However, the disadvantages of these approaches are that these have the data association Problem in tracking multiple targets. and that these require the heavy computational load in estimating a 2-D range/bearing spectrum. In case multiple targets are adjacent. the tracking performance degrades seriously because the estimate of each target's Position has a large error. In this paper, we proposed a new tracking algorithm using Position innovations extracted from the senor output covariance matrix in the near field. The proposed algorithm is demonstrated by the computer simulations dealing with the tracking of multiple closing and crossing targets.

• Journal of the Korean Society for Library and Information Science
• /
• v.50 no.1
• /
• pp.189-207
• /
• 2016

Sharing and reutilizing of research data could not only enhance efficiency and transparency of research process, but also create new science through data integrating and reinterpretationing. Diverse policies about research data sharing and reutilizing have been developing, along with extending of research evaluating spectrum that across research data citation rate to social impact of research output. This study analyzed the scale and citation number of research data which has not been analyzed before in korea through data citation index using Kruskal-Wallis H analysis. As result, genetics and biotechnology are identified as subject areas which have most huge number of research data, however the subject areas that have been highly cited are identified as economics and social study such as, demographic and employment. And Uk Data Archive, Inter-university Consortium for Political and Social Research are analyzed as data repositories which have most highly cited research data. And the data study which describes methodology of data survey, type and so on shows high citation rate than other data type. In the result of altmetrics of research data, data study of social science shows relatively high impact than other areas.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.2 no.3
• /
• pp.317-323
• /
• 1998

A synchronization is important element not only wire communication but also wireless communication. Especially, In SS(Spread Spectrum) communication method used GPS(Global Positioning System) synchronization is more important. A synchronous oscillator(SO) is a network which synchronizes, tracks, filter, amplifies and divides (if necessary) in a single process. Without an input signal, the SO is a free-running oscillator, oscillating at a frequency $w_0$, but phase changes $180^{\circ}$ within tracking range of SO. Therefore CPSO was used for this problem. The coherent phase synchronous oscillator(CPSO) is created by adding two external loops to the SO and has a wider tracking bandwidth and a zero-offset phase response (coherent) while maintaining the SO properties of high signal-to-rejection and fast frequency acquisition times. Therefore phase between input signal and output signal is synchronized. In this paper, GPS data recovery circuit has applied CPSO using front reference characters and has certified an excellent data recovery capability.