• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.147-148
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• 2006

Relative phase distribution of onion epidermal cells was measured by using the relative phase microscope with inverse linear polarizing method. Decrease of relative phase distribution of onion epidermal cells was also investigated as the elapse of time. In decrease of relative phase distribution, relative phase of cell membrane in onion epidermal cells decreased radically as compared with that of cytoplasm.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.242-247
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• 1990

By self-homodyne method we measured the relative phase fluctuation of a light wave. Balanced detection system can eliminate local oscillator excess noise and multiport detection makes it possible ot measure the phase change of the signal beam. Deriving the SB(Signal Beam) and the LO(Local Oscillator) from the same laser source, we find the SB maintain constant phase relative to that of the LO. We have introduced a phase fluctuation in the SB by modulating the beam path of the SB. The measured phase fluctuation agreed well with the predicted one, thereby we confirmed the reliability of our system.

• Journal of Astronomy and Space Sciences
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• v.33 no.1
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• pp.45-54
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• 2016

This study developed an approach for improving Carrier-phase Differential Global Positioning System (CDGPS) based realtime satellite relative navigation by applying laser baseline measurement data. The robustness against the space operational environment was considered, and a Synthetic Wavelength Interferometer (SWI) algorithm based on a femtosecond laser measurement model was developed. The phase differences between two laser wavelengths were combined to measure precise distance. Generated laser data were used to improve estimation accuracy for the float ambiguity of CDGPS data. Relative navigation simulations in real-time were performed using the extended Kalman filter algorithm. The GPS and laser-combined relative navigation accuracy was compared with GPS-only relative navigation solutions to determine the impact of laser data on relative navigation. In numerical simulations, the success rate of integer ambiguity resolution increased when laser data was added to GPS data. The relative navigational errors also improved five-fold and two-fold, relative to the GPS-only error, for 250 m and 5 km initial relative distances, respectively. The methodology developed in this study is suitable for application to future satellite formation-flying missions.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.694-697
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• 2016

Up-converted phase noise, which is induced by the low-frequency relative intensity noise (RIN) of a laser through AM-PM conversion within a photodetector (PD), is first measured here by means of a cross-correlation method. Our proposed measurement system can isolate the RIN-induced phase noise from noise contributions of other components, such as amplifiers, modulators, and mixers. In particular, shot noise and thermal noise generated from the PD are also suppressed by this method, so that standalone characteristics of the RIN-induced phase noise can be obtained. Experimental results clearly show the quantitative relationship between the RIN-induced phase noise and the incident optical power of the PD. Our findings indicate that the least RIN-induced phase noise appeared at the saturation point of the PD, which is about -162 dBc/Hz at 10 kHz offset.

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.147-156
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• 2000

To investigate fatty acid constituents and relative compositions in the fluid of the follicles, oviducts, uterine body and uterine body in Korean native cow, the fluids of the reproductive tract were analyzed using gas chromatography. The samples were taken from various reproductive tract of 23 Korean native cows. q. Caprylic acid (C8:0), myristic acid(C14:0), palmitic acid(C16:0), palmitoleic acid(C16:1), stearic acid(C18:0), oleic acid(C18:1), linoleic acid(C18:2), arachidonic acid(C20:4) were found in the reproductive tracts of the cows, which made 8 kinds of fatty acid in total. 2. Palmitic acid, oleic acid, stearic acid were predominant with 35.67%, 24.98% and 17.52%, respectively. while low levels of fatty acids(<5%) were myristic acid, palmitoleic acid and caprylic acid with 1.75%, 1.28% and 2.69%, respectively. 3. Two kinds of polyunsaturated fatty acids, linoleic acid arachidonic acid were found in the reproductive tracts of cows. 4. Palmitic acid among saturated fatty acids and oleic acid among unsaturated fatty acids were the highest level in all of the reproductive tracts. 5. The Highest level of arachidonic acid was found in the uterine horn. 6. The sum of the palmitic acid and oleic acid were 61.72%, 63.72%, 57.66% and 57.65% for the fluid of follicle, oviduct, uterine horn and uterine body of the cows, respectively. 7. The relative compositions of palmitic acid, palmitoleic acid and caprylic acid were higher during the luteal phase than during the follicular phase. 8. The relative compositions of arachidonic acid was higher during the follicular phase in the fluid of uterine horn and uterine body of the cows. 9. The long chain fatty acid, the palmitic acid, stearic acid, oleic acid and linoleic acidshowed higher relative compositions during the follicular phase(86.49%∼95.51%) than during the luteal phase(85.64%∼88.93%).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.3-10
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• 2005

Every cell position of a maximum-length 90/150 cellular automata(CA) generates the same pseudo-noise(PN) sequence corresponding to the characteristic polynomial of the CA with a phase shift. Unlike LFSRs, the phase shift is generally different between stages of a CA. In this paper, we propose an algorithm to compute relative phase shifts between stage of a CA. Our algorithm does not need Shank's algorithm to compute relative phase shifts and does not need any previous phase shifts to compute a phase shift. Moreover it is done in time $O(2^n)$.

• Journal of Astronomy and Space Sciences
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• v.37 no.3
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• pp.187-197
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• 2020

In order to avoid the high cost and high risk of demonstration mission of rendezvous-docking technology, missions using nanosatellites have recently been increasing. However, there are few successful mission cases due to many limitations of nanosatellites like small size, power limitation, and limited performances of sensor, thruster, and controller. To improve the probability of rendezvous-docking mission success using nanosatellite, a rendezvous-docking phase analysis tool for nanosatellites is developed. The tool serves to analyze the relative position and attitude control of the chaser satellite at the docking phase. In this tool, the Model Predictive Controller (MPC) is implemented as a controller, and Extended Kalman Filter (EKF) is adopted as a filter for noise filtering. To verify the performance and effectiveness of the developed tool for nanosatellites, simulation study was conducted. Consequently, we confirmed that this tool can be used for the analysis of relative position and attitude control for nanosatellites in the rendezvous-docking phase.

• Journal of Astronomy and Space Sciences
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• v.26 no.1
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• pp.59-74
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• 2009

Relative navigation system is presented using GPS measurements from a single-channel global positioning system (GPS) simulator. The objective of this study is to provide the real-time inter-satellite relative positions as well as absolute positions for two formation flying satellites in low earth orbit. To improve the navigation performance, the absolute states are estimated using ion-free GRAPHIC (group and phase ionospheric correction) pseudo-ranges and the relative states are determined using double differential carrier-phase data and singled-differential C/A code data based on the extended Kalman filter and the unscented Kalman filter. Furthermore, pseudo-relative dynamic model and modified relative measurement model are developed. This modified EKF method prevents non-linearity of the measurement model from degrading precision by applying linearization about absolute navigation solutions not about the priori estimates. The LAMBDA method also has been used to improve the relative navigation performance by fixing ambiguities to integers for precise relative navigation. The software-based simulation has been performed and the steady state accuracies of 1 m and 6 mm ($1{\sigma}$ of 3-dimensional difference errors) are achieved for the absolute and relative navigation using EKF for a short baseline leader/follower formation. In addition, the navigation performances are compared for the EKF and the UKF for 10 hours simulation, and relative position errors are mm-level for the two filters showing the similar trends.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.23.5-23
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• 2001

This paper is concerned with the vehicle platooning in the AHS (Automated Highway Systems). For this, a relative navigation system is developed for the vehicles operating as a platoon. The relative navigation system is based on two sensors including GPS and MMWR (Millimeter-Wave Radar) and the federated Kalman Iter processing measurements of them. The architecture of this system requires GPS measurements of a preceding vehicle via communication link. Even if GPS measurements are available, they contain errors which are unacceptably high in vehicle platooning. Therefore, GPS carrier phase is considered. Integer ambiguities of GPS carrier phase measurements are determined by using MMWR ...

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.137-145
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• 2000

To investigate fatty acid constituents and relative compositions in the fluid of the follicles, oviducts, uterine ho군 and uterine body in sows, the fluids of the reproductive tract were analyzed using Gas chromatography. The samples were taken from various reproductive tract of 21 sows slaughtered. 1. Caprylic acid(C8: 0), capric acid(C10:0), lauric acid(C12:0), myristic acid(C14:0), palmitic acid(C16:0), plamitolele acid(C16:1), stearic acid(C18:0), oleic acid(C18:1), linoleic acid(C18:2) and arachidonic acid(C20:4) were found in the reproductive tracts of the sows, which made 10 kinds of fatty acid intotal. 2. Two kinds of polyunsaturated fatty acids, linoleic acid and archidonic acid were found inthe reproductive tracts. 3. Palmitic acid among saturated fatty acids and oleic acid among unsaturated fatty acids were the hihgest level in all of the reproductive tracts. 4. Palmitic acid, oleic acid and stearic acid showed higher rate with 44.89%, 23.69% and 14.36%, respectively, and lauric acid, capric acid, palmitoleic acid, arachidonic acid ad myristic acid showed lower rate with 0.62%, 1.13%, 1.65%, 1.97% and 2.24%, respectively in the reproductive fluid. 5. The highest level of arachidonic acid was found in the uterine horn. 6. The sum of the palmitic acid and oleic acid were 66.91%, 70.41%, 66.14% and 73.36% in the fluid of follicle, oviduct, uterine horn and uterine body, respectively. 7. The relative composition of arachidonic acid was higher during the follicular stage than during the luteal phase in the fluid of oviduct and uterine. 8. The long chain fatty acids such as the palmitic acid, stearic acid, oleic acid and linoleic acid showed higher relative compositions during the follicular phase(93.18%∼96.83%) than during the luteal phase(82.56%∼88.37%). 9. Caprylic acid, luric acid and palmitoleic acid were undetected in the fluid of all of the reproductive tracts during the follicular phase. Low relative compositions of capric acid, myristic acid andarachidonic acid were found during the follicular phase, while the low relative compositions (<5%)of capric acid, lauric acid, myristic acid, plamitoleic acid and arachidonic acid were found during the luteal phase.