• Journal of Environmental Science International
• /
• v.23 no.1
• /
• pp.81-88
• /
• 2014

In this study, one of the measures for the promotion of the growth of trees planted in poor drainage areas, which functionality pipe supplying oxygen in the soil, and promotes drainage, barren soil and poor drainage areas in planting design was to provide the basic data to compare the impact on the application of functionality pipe. The Zelkova serrata testing materials were selected, planted a total of 12 by three to four individual experiments were conducted. Growth measurements of the items Plot A > Plot C > Plot D > Plot B were excellent in the order of height, number of leaves, leaf width, and chlorophyll content, Plot A > Plot C > Plot D > Plot B was in good order of the growth of the length of the root-collar diameter, Plot C > Plot A > Plot B > Plot D in order rate of variation was good. This has adverse effects on plant growth, poor drainage planting base represents, promote drainage and oxygen supply technique can be applied good to the planting from Zelkova serrata growth based drainage is poor and barren presented as part of research to be done in the future include a means for promoting the growth of plants in soil, the planting design.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.2
• /
• pp.303-308
• /
• 2001

An objection of this study is to develop a high stable measuring circuits and a analytic system for radioactive pulses. The proposed system consists of a pulse detection units for neutrons and gamma-rays a programmable high voltage supply unit and a digital signal processor. The programmable high voltage supply unit designed can generate DC voltage up to 1,500 V at 5 V input and have a series voltage regulator to maintain the output voltage constantly, resulting in less than 1.63% of voltage regulation. The pulse detection parts consists of an active integrator, a pole-zero circuit, and a 3-stage amplifier of 60 dB, and its frequency bandwidth is from 37 Hz to 300 kHzAlso, pulse height distribution in accordance with pulse counts is important data in analyzing radioactive pulses. In this study, A/D convertor (12bit, 100ms) and DSP (TMS320C31-60) are used to analyze the pulse height, and the analytic system is designed to be operated in PC-base.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.7
• /
• pp.715-725
• /
• 2010

Orthgonal Frequency Division Multiplexing(OFDM) system is effective for the high data rate transmission in the frequency selective fading channel. In this paper we propose PAPR(Peak to Average Power Ratio) reduction method of problem in OFDM system used Fuzzy theory that often control machine. This thesis proposes PAPR reducing method of OFDM system using Fuzzy theory. The advantages for using Fuzzy theory to reduce PAPR are that it is easy to manage the data and embody the hardware, and required smaller amount of operation. Firstly, we proposed simple algorithm that is reconstructed at receiver with transmitted overall PAPR which is reduced PAPR of sub-block using Fuzzy. Although there are some drawbacks that the operation of the system is increased comparing conventional OFDM system and it is needed to send the information about Fuzzy indivisually, it is assured that the performance of the system is enhanced for PAPR reducing. To evaluate the perfomance, the proposed search algorithm is compared with the proposed algorithm in terms of the complementary cumulative distribution function(CCDF) of the PAPR and the computational complexity. As a result of using the QPSK and 16QAM modulation, Fuzzy theory method is more an effective method of reducing 2.3 dB and 3.1 dB PAPR than exiting OFDM system when FFT size(N)=512, and oversampling=4 in the base PR of $10^{-5}$.

• Nuclear Engineering and Technology
• /
• v.23 no.1
• /
• pp.66-80
• /
• 1991

The LOFT intermediate break experiment L5-1, which simulates 12 inch diameter ECC line break in a typical PWR, has been analyzed using the reactor thermal/hydraulic analysis code RELAP5/MOD2, Cycle 36.04. The base calculation, which modeled the core with single flow channel and two heat structures without using the options of reflood and gap conductance model, has been successfully completed and compared with experimental data. Sensitivity studies were carried out to investigate the effects of nodalization at reactor vessel and core modeling on major thermal hydraulic parameters, especially on peak cladding temperature(PCT). These sensitivity items are : single flow channel and single heat structure (Case A), two flow channel and two heat structures (Case B), reflood option added (Case C) and both reflood and gap conductance options added (Case D). The code, RELAP5/MOD2 Cycle 36.04 with the base modeling, predicted the key parameters of LOFT IBLOCA Test L5-1 better than Cases A,B,C and D. Thus, it is concluded that the single flow channel modeling for core is better than the two flow channel modeling and two heat structure is also better than single heat structure modeling to predict PCT at the central fuel rods. It is, therefore, recommended to use the reflood option and not to use gap conductance option for this L5-1 type IBLOCA.

• 한국전산유체공학회:학술대회논문집
• /
• 2009.04a
• /
• pp.303-309
• /
• 2009

In this study, the heat transfer and flow field of condenser used on Kim-chi refrigerator is analysed with numerical method. Main objective is to present the base data for designing new condenser model with improvement of heat transfer performance. For CFD analysis, a commercial code, STAR-CCM+ was used. The water was used for the inner working fluid and the air was used for the outer fluid. The condenser type used in this study is a flat plate fin-and-tube heat exchanger. As factors for performance analysis, the effect of condenser geometry and air velocity was investigated. As a result, it has been observed that there is a suitable fin pitch with which heat transfer performance of condenser is maximized.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.252-257
• /
• 1999

The distinguished geological characteristic of Taegu area is consist of anisotropic shale or sedimentary rock. Therefore if rocks are used for construction, it would've some difficulties of reuse showing the aspect of resource engineering. We made physical and mechanic properties for rock discrimination and then whether it had utilization worth or not. So we studied the engineering propriety through the aggregate tests based on rock's in laboratory. The last passed aggregate were D, E and B1 at KS and the rest couldn't use the place where weather phenomenon is caprice. This sis for base-line data of aggregate development research before the porpriety investigation for aggreagte of excavated rock in Taegu area.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.10
• /
• pp.1183-1188
• /
• 2015

The FM-QCSK(: Frequency Modulated Quadrature Chaos Shift Keying) system is one of the most efficient systems in chaotic literature. One of the problems in this system is that half the bit duration is used for sending a chaotic reference signal which leads to increase the energy losses and reduces the data rate. In this paper, a novel scheme to enhance the performance of FM-QCSK system has been proposed. With the proposed scheme, FM-QCSK would be able to operate at higher data rates with reduced BER(: Bit Error Rate) and energy consumption. The basic modification introduced by the proposed scheme is the use one reference chaotic signal to transmit multi information signals in both in-phase and quadrature-phase channels. The results showed that the proposed scheme have achieved more than 3 dB gains in SNR for AWGN channels respectively at $BER=10^{-3}$ over the conventional one. The results also showed that the optimum number information signals can be send per reference signal is 8.

• Journal of the Institute of Convergence Signal Processing
• /
• v.8 no.4
• /
• pp.266-271
• /
• 2007

In mobile channel environments, the effect of the multi-path fading reduces the performance of the mobile communication severely. Previous studies on the effect of the multi-path fading show that, only the channel between fixed base stations and mobile terminals are considered. However, the future mobile communication service such as telematics may use the communication between moving mobile terminals, so called mobile ad-hoc communication, the studies on the channel is required for such situations. In this paper we have measured the mobile channel and analyzed the fading characteristics when using the linear array antennas. In the data measurements, we sent the QPSK modulated signal with carrier frequency of 2GHz band and received the signal using the array antennas equipped on moving vehicles. We have analyzed the fading characteristics and the effects of the fading reduction using the CDF of fading depth using data collected from two moving vehicles. The simulation results show that the beamforming technique adds 6 or 7dB to the fading margin than that of the selection diversity depending on channel environments.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.234-238
• /
• 2007

Since the plant industry is a total business, it has great impact on the related industries and generates high value. However, in order to have a competitive engineering skills and capabilities, the plant industry requires long-term investment and a continuous strategic planning at the consortium level or national level. Also, a system needs to be established to share the information of the plant industry's overseas orders awarded and success factors. Thus, this study has conducted a survey and case study of the plant construction in foreign countries. Statistical analysis was performed and a basic data structure was built as a means of improving the future technological capabilities of the plant industry.

• Korean Journal of Pharmacognosy
• /
• v.33 no.4 s.131
• /
• pp.399-403
• /
• 2002

Three melanogenesis inhibitors were isolated from the roots and rhizomes of Veratrum nigrum L. and were identified as (3S,20S,25S)-22,26-iminocholesta-5,22(N)-dien-3-ol (verazine), (3S,2OR,25S)-22,26-iminocholesta-5,22(N)-dien-3-ol (epi-verazine) and (3R,23R)-14,15,16,17- tetradehydroveratraman-3,23-diol (veratramine) on the basis of their spectroscopic data. It was turned out that these compounds did not directly inhibit tyrosinase activity, the key enzyme responsible for the formation of melanin pigment while these compounds showed strong inhibition on the melanogenesis in B16 F1 mouse melanoma $(IC_{50}<1\;{\mu}g/ml)$. Due to the strong inhibitory activity and safety compared to current whitening agents such as arbutin, kojic acid and AHA, the compound can be a good candidate for new skin whitening agents.