• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1464-1474
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• 1994

GPS(Global Positioning System)is a satellite-based navigation system that we can survey where we are, anywhere and anytime. In this paper, delay-lock loop of the receiver which detects the navigation data is theoretically analyzed, and designed using the digital logic circuit. Also logic operations for the synchronization are analyzed. The designed system consists of the correlator which correlates the received C/A code and the generated C/A code in the receiver, the C/A code generator which generates C/A code of selected satellite, and the direct digital clock syntheizer which generates the clock of the C/A code generator to control the C/A code phase and clock rate. From the analyses results of the proposed digital delay-lock loop system, the system has the detection propertied over 90% when its input signal power is above-113.98dB. The influence of input signal variation of digital delay loop, which is the input of A/D converter, is investigated and the performance is analyzed with the variation of threshold level via the computer simulation. The logic simulation results show that the designed system detects precisely the GPS navigation data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.998-1004
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• 2002

This paper reports a design of feedforward linear power amplifier using pilot tone for IMT-2000 band repeaters accepting multi-carrier. As this time pilot tone is applied to the circuit differently from the existing method. Only one pilot tone is used in both 1-st loop(IMD abstraction loop) and 2-nd loop(IMD cancellation loop) to cancell IMD signals automatically according to variation of frequency or power level of input signals. As an experiment, in range of 2110 MHz - 2170 MHz at LPA output power of $20 W_{avg}$, IMD characteristics of over 20 dB was improved maintaining below -60 dBc considering respective 20 MHz. Therefore the supposed feedforward linear power amplifier can be used for linear power amplifier in IMT-2000 band repeaters.

• Journal of Power Electronics
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• v.15 no.1
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• pp.65-77
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• 2015

Resonant converters are well suited for induction heating (IH) applications due to their advantages such as efficiency and power density. The control systems of these appliances should provide smooth and wide power control with fewer losses. In this paper, a simple phase locked loop (PLL) based variable duty cycle (VDC) pulse density modulation (PDM) power control scheme for use in class-D inverters for IH loads is proposed. This VDC PDM control method provides a wide power control range. This control scheme also achieves stable and efficient Zero-Voltage-Switching (ZVS) operation over a wide load range. Analysis and modeling of an IH load is done to perform a time domain simulation. The design and output power analysis of a class-D inverter are done for both the conventional pulse width modulation (PWM) and the proposed PLL based VDC PDM methods. The control principles of the proposed method are described in detail. The validity of the proposed control scheme is verified through MATLAB simulations. The PLL loop maintains operation closer to the resonant frequency irrespective of variations in the load parameters. The proposed control scheme provides a linear output power variation to simplify the control logic. A prototype of the class-D inverter system is implemented to validate the simulation results.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.218-225
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• 2005

This study was performed to determine sequence variation and RFLP of the mt DNA D-loop region using Southern blot hybridization analysis and to develop mt DNA marker affecting milk production traits in Hanwoo cows. The PCR was used to amplify an 1142 bp fragment within the D-loop region of mt DNA using specific primers. Mt DNA were digested with seven restriction enzymes and hybridized using DIG-labeled D-loop probe. The mt DNA RFLP polymorphisms were observed in the four enzymes, BamHI, RsaI, XbaI and HpaII. Nucleotide substitutions were detected at positions 441 (G/C), 469 (T/C), 503 (C/T), 569 (G/A), 614 (C/A) and 644 (C/T) of the mt DNA D-loop region between two selected lines. Significant relationship between the XbaI RFLP type and breeding value was found(p<0.05). Cows with A type had higher estimated breeding values than those with B type (P<0.05) between high and low milk production lines. Therefore, the RFLP marker of mt DNA could be used as a selection assisted tool for individuals with high milk producing ability in Hanwoo.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.303-310
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• 2011

Phylogenetic relationships of Jeju dogs to other domestic and foreign dog breeds were assessed using mtDNA D-loop sequences. Neighbor-joining trees were constructed using complete sequences (970 bp excluding the tandem repeat region) determined for five Cheju, four Jindo, four Sapsaree, five Pungsan, two of each East and West Laika dogs (Canis familiaris), two gray wolves (Canis lupus) and two coyotes (Canis latrans) and also published complete sequences for dogs. Coyote sequences were used as outgroups. In addition, a total of 214 haplotypes of 598bp D-loop sequences from 30 dog breeds were collected from GenBank and used to investigate genetic structure of population. In the analyses of full D-loop sequence variation and the phylogenetic trees constructed by neighbor-joining method, neither haplotypes nor clades specific for any domestic dog breeds were observed. The inter-species sequence variation (4.51%) between domestic dogs and wolves was much higher than the intra-species sequence variation within domestic dogs (1.63%) and wolves (3.64%). The divergence of the dog and wolf occurred approximately 1~2 million years ago based on these values. The taxa of Jeju dog breed in the phylogenetic tree are clustered separately and intermingled with other taxa of breeds, suggesting that active crossbreeding of Jeju dogs with other domestic breeds.

• Journal of the Optical Society of Korea
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• v.4 no.1
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• pp.14-18
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• 2000

We have investigated gain flattening of EDFA systems with or without a gain equalizer for WDM long-haul transmission using a re-circulating EDFA loop. Without a gain equalizer, gain variation as small as 2.9 dB was achieved over the 10-nm band of a 100 cascaded EDFA system by the inversion principle. With a gain equalizer based on all-fiber acousto-optic tunable filters, two different config-urations of EDFAs were tested. For a single-stage EDFA scheme, the 21-nm band has shown 3.8 dB of gain variation at 17.4 ∼ 20.3 dB of OSNRs after the 100the stage of EDFAs. For a dual-stage EDFA scheme, a wider bandwidth of 34 nm has shown 3.6-dB variation after 40 cascaded EDFAs.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.178-183
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• 2007

China has numerous native domestic goat breeds, but so far there has been no extensive study on genetic diversity, population demographic history, and origin of Chinese goats. To determine the origin and genetic diversity of Chinese goats, we analyzed the complete mtDNA D-loop sequences of 183 goats from 13 breeds. The haplotype diversity value found in each breed ranged from 0.9333 to 1.0000. The nucleotide diversity value ranged from 0.006337 to 0.025194. Our results showed that there were four mtDNA lineages (A, B, C and D), in which lineage A was predominant, lineage B was moderate, and lineages C and D were at low frequencies. Lineages C and D were observed only in the Tibetan breed. The results revealed multiple maternal origins of Chinese domestic goats. There was weaker geographical structuring in the 13 Chinese goat populations, which suggested that there existed high gene flow among goat populations caused by the extensive transportation of goats in the course of history.

• Smart Structures and Systems
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• v.26 no.6
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• pp.797-807
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• 2020

Due to the influence of nonlinearity and time-variation, it is difficult to establish an accurate model of concrete frame structures that adopt active controllers. Fuzzy theory is a relatively appropriate method but susceptible to human subjective experience to decrease the performance. This paper proposes a novel artificial intelligence based EBA (Evolved Bat Algorithm) controller with machine learning matched membership functions in the complex nonlinear system. The proposed affine transformed membership functions are adopted and stabilization and performance criterion of the closed-loop fuzzy systems are obtained through a new parametrized linear matrix inequality which is rearranged by machine learning affine matched membership functions. The trajectory of the closed-loop dithered system and that of the closed-loop fuzzy relaxed system can be made as close as desired. This enables us to get a rigorous prediction of stability of the closed-loop dithered system by establishing that of the closed-loop fuzzy relaxed system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.2
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• pp.91-97
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• 2000

Tn this paper, a novel control circuit applicable to the error sensor loop block in the feedforward linearizer system is proposed. The proposed control circuit is applied to the error sensor loop block, where in the 11dB power range, it operates stably, and makes main carrier signals to be eliminated more than 40dB below 3$\^$rd/ order IM level. In the operating point, the amplitude control error is 0.05∼0.12dB, and the phase control error is smaller than 0.02。. It is verified theoretically as well as experimentally that the control circuit can precisely compensate the variation of nonlinear characteristics in a high power amplifier, due to the variations of input power, operating temperature, humidity and the other system environments.

• Korean Journal of Optics and Photonics
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• v.9 no.6
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• pp.413-416
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• 1998

We have flattened the gain of EDFA by using a long-period FBG filter and AOTF's. The gain and optical SNR characteristics of the gain-flattened EDFA in long-haul transmission been evaluated in a recirculating EDFA loop. The gain variation was less than 4.6 dB and the optical SNR was higher than 14 dB over 20-nm wavelength range when the optical signal went through the EDFA as many as 200 times. These results indicate that this gain-flattened EDFA is applicable for ultra long-haul WDM optical transmissions over 8000 km.