• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.4 s.119
• /
• pp.416-422
• /
• 2007

In this paper, a broadband 2-way power divider which can be used from 20 MHz to 500 MHz in the V/UHF band is designed using transmission-line transformer and ferrite toroid. A 2:1 impedance transformer instead of the conventional 4:1 impedance transformer is realized and this 2:1 transformer is connected with the conventional bridge-type 2-way divider to form a 2-way power divider. Insertion loss of about 3.5 dB, isolation of less than -10 dB, and return loss of less than -10 dB in most band of interest are measured.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.39 no.4
• /
• pp.36-42
• /
• 2002

In this paper, we proposed a multiplicative algorithm for two polynomials with all non-zero coefficients over finite field GF($P^m$). Using the proposed multiplicative algorithm, we constructed the multiplier of modular architecture with parallel in-output. The proposed multiplier is composed of $(m+1)^2$ identical cells, each cell consists of one mod(p) additional gate and one mod(p) multiplicative gate. Proposed multiplier need one mod(p) multiplicative gate delay time and m mod(p) additional gate delay time not clock. Also, our architecture is regular and possesses the property of modularity, therefore well-suited for VLSI implementation.

• Journal of Advanced Navigation Technology
• /
• v.16 no.2
• /
• pp.227-233
• /
• 2012

This paper presents a bandpass fitler of GPS and WLAN band based on LTCC. The structure of bandpass fitler consists of a Butterworth lowpass fitler and highpass filter using CRLH (Composite Right/Left-Handed) transmission line. Using green sheet with dielectric constant 7.2, we fabricated the bandpass filter that satisfied GPS and WLAN band characteristics. We are implemented the bandpass filter at center frequency 1.5 GHz (GPS) and 2.4 GHz (WLAN). Its insertion loss are 1.66 dB at GPS and 3.20 dB at WLAN respectively.

• Current Research on Agriculture and Life Sciences
• /
• v.32 no.3
• /
• pp.165-169
• /
• 2014

This study assessed the economic feasibility of an automatic egg washer. Based on various cost benefit analysis methods, including the net present value (NPV), internal rate of return (IRR) and benefit cost ratio (B/C Ratio), the automatic egg washer was confirmed to have economic feasibility. The NPVs were 38,565,991 won at 5% discount rate and 32,013,916 won at 10% discount rate, respectively. The IRRs were 1.325 at 5% discount rate and 1.299 at 10% discount rate, respectively. Finally, the B/C ratios were 1.726 at 5% discount rate and 1.699 at 10% discount rate.

• Journal of Sericultural and Entomological Science
• /
• v.13 no.2
• /
• pp.145-150
• /
• 1971

During 1968-1970, rearing method being held yearly through was conducted to find adequate rearing season under joint projects in various areas; Chung-nam area, Kyung-buk area, Chun-nam area. The results are summarized as follows: 1. In view of rearing results, earlier transfer represents better, in spring season while early transfer worst in autumn season. If the conventional transfer sets on critical point in autumn season, the value recorded gradually decreased in earlier and later transfer and rapidly in earlier and later. 2. With rearing season, obtained results are degraded in order of spring(1st-4th), autumn(7th-10th), late autumn(11th), summer(5th) , early autumn(6th). Late autumn transfer could be delayed for about 6-7 days in southern area. 3. With referrence to rearing results alone, it may be concluded that 4 time ordinary rearing is adoptable in multi-rearing method, dividing into 2 seasons which are 2 time spring rearing(1st-3rd) and 2 time autumn rearings(8th-10th).1st period of spring rearing should be done 3-4 days ahead of the conventional transfer dates being practiced in each local, and 2nd period of spring transfer 5-6 days delayed. In autumn transfer, 2-5 days ahead and 3-6 days delayed batches tested are preferable. In branch rearing, it is recommended that 4 time branch rearing is conducted to divide into 2 seasons which are 2 time spring rearing(1st-3rd) and 2 time autumn rearing (9th-11th) and that the former is carried out in the same level of the 2 time spring rearing, latter in the same level of the conventional autumn .earing (9th) , and late autumn rearing (11th).

• Microbiology and Biotechnology Letters
• /
• v.26 no.1
• /
• pp.1-6
• /
• 1998

The characteristics of $CO_2$ fixation by Chlorella HA-1 cultured in bubble columns were studied to achieve high photosynthetic rates per basal area. The influence of experimental conditions such as the diameter of a bubble column and gas flow rate, on photosynthesis of Chlorella HA-1 was investigated. The maximum productivity and the overall $CO_2$ fixation rate obtained in a 0.15 L bubble column was 1.09 g dry biomassa-day and 1048 g CO$_2/\m^2$-day, respectively. Light limitation has been observed in the bubble columns having a diameter larger than 3.5 cm.. As the reactor volume increased, the decrease of the $CO_2$ fixation rate was remarkable. High gas flow rate was helpful to mitigate the light limitation problem.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.8
• /
• pp.1188-1195
• /
• 2022

The 6-port phase correlator consists of one in-phase power divider and three 3-dB 90-degree phase difference power dividers, and is mainly used in a demodulation circuit that determines the phase of an input signal. This paper proposes the wideband 6-port phase correlator that consists of an in-phase power divider using a wideband 2:1 impedance transformer with three 37.5-Ω coaxial cables, and a 3-dB 90-degree phase difference power divide using Wireline. The proposed wideband phase correlator fabricated at a center frequency of 1000MHz has the value of the input reflection coefficient(S₁₁ and S₂₂) -14dB or less in the frequency range of 640~1270MHz. Also, the signal transmission characteristic(S_i1), from the in-phase power divider input port to four output ports, has the amplitude of -6.5±0.6dB and the phase error of within ±3.4°, and the signal transmission characteristic(S_i2), from the 90 degree phase difference power divider input port to four output ports, has the amplitude of -6.1±0.6dB and the phase error of within ±6.2°.

• Computational Structural Engineering
• /
• v.12 no.1
• /
• pp.125-136
• /
• 1999

• Journal of KIISE:Computer Systems and Theory
• /
• v.31 no.1_2
• /
• pp.112-117
• /
• 2004

In this paper, we propose a suitable multiplication architecture for cellular automata in a finite field $GF(2^m)$. Proposed least significant bit first multiplier is based on irreducible all one Polynomial, and has a latency of (m+1) and a critical path of $ 1-D_{AND}＋1-D{XOR}$.Specially it is efficient for implementing VLSI architecture and has potential for use as a basic architecture for division, exponentiation and inverses since it is a parallel structure with regularity and modularity. Moreover our architecture can be used as a basic architecture for well-known public-key information service in $GF(2^m)$ such as Diffie-Hellman key exchange protocol, Digital Signature Algorithm and ElGamal cryptosystem.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.4
• /
• pp.425-430
• /
• 1987

The present experiment was carried out to investigate the effects of direct sowing time and transplanting culture of Sculellaria baicalensis GEORGE on the grows, the yield and it's components. The results obtained are summarized as fallows; The number of days from seeding to emergence was recognized lineary negative correlation between seeding dates and transplanting dates. Plant height was longest on Apr. 15 Seeding and Apr. 1 transplanting, and was short in the early seeding and transplanting, and the late seeding and transplanting. Stem diameter was thickest on Apr. 15 seeding and Apr. 1 transplanting, and was thin in the early, and the late seeding and trasplanting. Length and dry weight of root were increased on Apr. 15 seeding. In the transplanting date, Length and dry weight of root were increased on Apr.1. Yield of dry root was highest in Apr. 15 seeding date. In the transplanting culture, yield of dry root was highest in Apr.1.