• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.337-344
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• 2020

The purpose of this study was to investigate the effect of theratainment low extremity complex exercise using unstable surface on knee and static plantar pressure in patient with genu varum. 25 adult subjects were recruited and randomized into stable surface exercise group(SEG) and unstable surface exercise group(UEG). Subjects carried out complex exercise(elastic band exercise & squat exercise) for 40 minutes, 4 times per week for 5 weeks. The knee joint distance and Q-angle of all subjects measured, the foot pressure measured distribution on the front and rear of both foots during pre and post. The most outcome at post was significantly improved than the pre outcome in the both group(p<.05). The result of this study show that the low extremity complex exercise using unstable surface may be appropriate for improving structure of knee joint and static plantar pressure in patient with genu varum. This will enable the application of low extremity complex exercise using unstable surface in rehabilitation therapy of genu varum and it will help guide the selection of the therapist as one therapeutic basis.

• Polymer(Korea)
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• v.38 no.4
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• pp.535-543
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• 2014

This work, which was about the synthesis of naphthalimidopropyl acrylate and GMA copolymers and their physical properties, investigated the compositions of the copolymer, the reactivity ratios of the monomer, resonance effect (Q), polar effect (e) and fluorescence of naphthalene. Azobisisobutyronitronitryl (AIBN) as an initiator was employed at $60^{\circ}C$ with dimethylformamide (DMF) of solvent for the copolymerization of NIPA. $r_1$ was found to be higher than $r_2$ from the reactivity ratios of the monomer obtained from Fineman-Ross (F-R), Kelen-$T{\ddot{u}}d{\ddot{o}}s$(K-T) methods. NIPA was found to be more copolymerized than GMA. $r_1{\cdot}r_2$ product was lower than 1, copolymerization was maked random-alternating type. The fluorescence spectrum of these polymers showed a weak monomer fluorescence band at 380 nm and a strong excimer fluorescence band at about 460 nm. Fluorescence life time of NIPA monomer showed fluorescence cover with UV 355 nm at room temperature, and life time showed $5.1449{\times}10^{-7}s$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.761-768
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• 2010

This paper presents an effective method to achieve the wideband waveform for high resolution SAR(Synthetic Aperture Radar) using the frequency multiplication technique. And also this paper analyzes the root causes for the spectral regrowth due to 3rd-order intermodulation in chirp bandwidth expansion scheme using quadrature modulator and frequency multipliers. The amplitude and phase imbalance requirement are defined based on the simulation results in terms of quadrature channel imbalance. This minimizes the degradation of range resolution, peak sidelobe ratio and integrated sidelobe ratio. The wideband chirp generator using the frequency multiplier and memory map scheme was manufactured and the compensation technique was presented to reduce the spectral regrowth of SAR waveform by minimizing the amplitude and phase imbalance. After I and Q channel imbalance adjustment, the carrier level reduces －28.7 dBm to －53.4 dBm. Chirp signal with 150 MHz bandwidth at S-band expands to 600 MHz bandwidth at X-band. The sidelobe levels are reduced by about 8 to 9 dB by compensating the amplitude balance between I and Q channels.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.59.2-59.2
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• 2015

We present the results of simultaneous observations of the H2O and SiO masers emitted from the circumstellar envelopes of the late-type stars. These observations have been carried out at the K and Q bands using KVN since 2014 August and were scheduled to test the feasibility of multi-frequency phase referencing analysis on the maser lines. In order to increase the accuracy of group delay solution in the fringe search on the continuum source, the IF channels were randomly distributed within the available bandwidth of 500 MHz in each band. The positions of all maser spots are relatively described with respect to the position of the reference continuum source through the source frequency phase referencing technique, and this provides the astrometric position accuracy. Therefore, the relative locations of the H2O maser spots with respect to the SiO maser spots are determined from our observations, and the capability of the simultaneous multi-band observation of KVN is proved to be powerful to study the maser pumping mechanism around the late-type stars.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.35.2-35.2
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• 2015

We present the results of simultaneous observations of the H2O and SiO masers emitted from the circumstellar envelopes (CSEs) of the late-type stars. These observations have been carried out at the four frequency bands (K, Q, W and D bands) using KVN to apply the source frequency phase referencing (SFPR) analysis to the maser lines. We obtain the relative positions between the H2O and the SiO maser spots by using the SFPR method, which are very important to study the physical links between the inner and the outer parts of the CSEs of the late-type stars. The relative positions between the SiO maser spots of the different transitions are also obtained very accurately, which are very crucial to investigate the pumping mechanism of the SiO maser lines. From our results, the capability of the simultaneous multi-band observation of KVN is proved to be powerful to study the complicated physical environments of the CSEs and the stellar evolution of the late-type stars.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.32-32
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• 2013

The Korean VLBI Network (KVN) as a world-first multi-frequency VLBI system is operated at four bands of 22, 43, 86, and 129 GHz simultaneously. The performances of both single dish and VLBI network were already confirmed through single dish researches and VLBI evaluation test observations. The VLBI common use of the KVN at 22/43 GHz bands has been started from this autumn. The combined network of KVN and Japanese VERA (KaVA) will start the common use from the first half of next year. Here we present several observational results in the fields of star forming regions, late-type stars, and active galactic nuclei using the KVN and KaVA. The fringes of 44 GHz $CH_3OH$ (Class I) masers were detected from 26 sources for the first time using the KVN and imaging observations are under performing. Simultaneous observations of SiO and $H_2O$ masers toward about 1000 evolved stars showed the different maser properties between SiO and $H_2O$ masers according to the evolutionary stages of AGB and post-AGB stars. The catalog of correlated flux densities were established from a 43 GHz (Q-band) survey of 637 extragalactic sources. At 22 GHz (K-band), flux density measurement and fringe survey for new sources were performed toward a large number of sources. In addition, the large program of KVN and/or KaVA under planning is introduced.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.2
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• pp.27-34
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• 1995

In this paper, an X-band TDRO(transistor dielectric resonator oscillator) is designed and experimented with the oscillator constructed. Design of the TDRO is carried out by deriving analycally the coupling parameters between a microstrip line and a dielectric resonator. The coupling parameters take account of the relations among substrate material, ground plane, metallic boundaries surrounding the resonator, distance between a microstrip line and a resonator. Two criteria, external quality factor and coupling coefficient, have been chosen in order to evaluate the performance of the TDRO designed. TDRO studed in this paper may be useful for the application of a microwave system requiring a stable and effective oscillator frequency.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.128-132
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• 2017

In this thesis, a BPF(band-pass filter) at the center frequency of 2.14GHz, and bandwidth of 20MHz is designed and implemented using high Q dielectric resonators with ${\varepsilon}_r=38$. The DR(dielectric resonator) is resonated by $TE_{01{\delta}}$-mode and it has a hole in the center of DR. The BPF consists of 6-poles dielectric resonators and the characteristic of elliptic function is obtained by non-adjacent coupling. It has the average insertion loss of 0.97dB and the return loss over 25dB in its passband. In this thesis, the frequency selectivity is more improved by the coupling characteristics between non-adjacent resonators than that of dielectric resonator filters with a Chebyshev response.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.205-207
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• 2003

In this paper, we propose novel, small and integrated microwave chip filter using high dielectric substrates. A variety of dielectric substrates can be selected for the specifications of products according to dielectric, Q-factors, temperature stability ect. This paper describes an application of the very high dielectric constant (K=133) substrate for design of a band pass filter to a 5.8GHz Transmitter/receiver(T/R) module.

• Agricultural and Biosystems Engineering
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• v.6 no.1
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• pp.1-7
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• 2005

Assessing health condition of crop in the field is one of core operation in precision fanning. A sensing system was proposed to remotely detect the crop health condition in terms of SP AD readings directly related to chlorophyll contents of crop using a multispectral camera equipped on ground-based platform. Since the image taken by a camera was sensitive to changes in ambient light intensity, it was needed to convert gray scale image data into reflectance, an index to indicate the reflection characteristics of target crop. A reference reflectance panel consisting of four pieces of sub-panels with different reflectance was developed for a dynamic calibration, by which a calibration equation was updated for every crop image captured by the camera. The system performance was evaluated in a field by investigating the relationship between com canopy reflectance and SP AD values. The validation tests revealed that the com canopy reflectance induced from Green band in the multispectral camera had the most significant correlation with SPAD values $(r^2=0.75)$ and NIR band could be used to filter out unwanted non-crop features such as soil background and empty space in a crop canopy. This research confirmed that it was technically feasible to develop a ground-based remote sensing system for assessing crop health condition.