• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.137-143
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• 2008

The spherical glasses lenses are typically classified into two groups such as (+) diopter lens and (-) diopter lens by the refractive power index. The thermal deformation of a lens is occurred by external heat source and is changed respected to the diopter of a lens. In this paper, the thermal deformation of spherical glasses lenses were quantitatively measured by using ESPI (electronic speckle pattern interferometry) which has an advantage that the non-contact, non-destructive and precise deformation measurement is available due to the coherency characteristic. The temperature changes were measured by IR camera. It makes experiments over 14 types of the plastic glasses lenses. From the results, it was confirmed that the larger diopter lens showed the less thermal deformation in case of the (+) diopter lens. On the other hand, the thermal deformation of the (-) diopter lens was measured with uniform pattern when the same temperature changes were applied. Also, it was found that the thermnal deformation of the (+) diopter lens is less than that of the (-) diopter lens. Therefore, it is expected that when the thermal deformation is occurred to the various types of the lens, the variation of the focal length caused by the thermal distortion of a lens would be measured quantitatively.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.221-225
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• 1999

In this paper, a new type of predistortion linearizer has been studied. It employs a series feedback amplifier with a large source inductance as a predistortion linearizer, which provides positive amplitude and negative phase deviations for input Power and can compensate for AM-AM and AM-PM distortions of power amplifier. This predistortion lineariaer consists of only one CaAs FET, large source inductor, input output matching networks and bias circuits. Because of its simple circuit, the linear can be operated over a broad bandwidth and has good thermal stability The characteristics of this linearizer can be easily tuned using source inductor, its gate bias condition. In fabricated linearizer, the third-order intermodulation distortion(IMD) for main amplifier alone is 10.61dBc, and the $IM_3$ for main amplifier with predistorter is 21.91dBc. Therefore, the $IM_3$ characteristic results an improvement of approximately 11dB.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.57-62
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• 2014

This paper proposes the improving the equalization performance using the adaptive modulus concept to the MCMA blind equalizer in order to the reduction of intersymbol interference which occurs in the band limited and time dispersive communication channel. In MCMA blind algorithm, it is possible to reducing the amplitude and phase rotation of intersymbol interference without training sequence, the fixed constant modulus of transmission signal is used. But in proposed algorithm, the modulus are adaptively varies according to the equalizer output signal, then the improved equalization performance were obtained by the computer simulation. For this, the recovered signal constellation that is the output of the equalizer, the convergence performance by MSE, MD (maximum distortion) and residual isi characteristic learning curve were used. The propose algorithm has fairly good performance compared to the traditional MCMA algorithm in the same adaptive equalization algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.79-86
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• 2005

This paper describe a method for measuring line impedance as a function of frequency for an energized powerline in normal operation. A small sinusoidal signal of a powerline communication utility frequency $30khz\~1Mhz$ band is continuously injected into the line, and a implemented impedance analyzer calculates the indoor powerline channel impedance from the measured magnitude and phase of resulting voltage and current. The impedance measurement is executed over a range of frequencies to produce a wideband impedance versus frequency characteristic. Implemented impedance analyzer can analysis powerline communication environments measuring line impedance due to load caused in indoor. And measured analysis information through the database can use to evaluate performance of modem and to decide test environment standard.

• Food Science and Preservation
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• v.13 no.2
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• pp.269-272
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• 2006

Aroma compounds in chungkukjang with Astragalus membranaceus (Hwangki) were extracted by the simultaneous distillation and extraction (SDE), headspace and solid phase microextraction (SPME), and aroma compounds obtained by this method were identified with GC-MS. Thirty compounds were identified, including six ketones, eight alcohols, three heterocyclic compounds, three aldehydes, five hydrocarbones and five other compounds. Major aroma compounds were identified as 3-hydroxy-2-butanone, 2-furanmethanol, 2-methoxy-4-vinylphenol, and 4-vinylphenol in SDE, 2,3-butanedione, 3-hydroxy-2-butanone, ethanol, 2,6-dimethyl pyrazine and acetic acid in headspace and acetone, ethanol, 2,5-dimethyl pyrazine, tetramethyl pyrazine and acetic acid in SPME. The content of pyrazines identified in headspace and SPME methods was higher than that of SDE method, and the content of pyrazines containing 2,5-dimethyl pyrazine, 2,6-dimethyl pyrazine and tetramethyl pyrazine in chungkukjang was higher than that of Hwangki chungkukjang.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1123-1129
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• 2006

Pyrene of natural and anthropogenic sources is one of the toxic, mutagenic polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants. The objectives of this research are to break down pyrene by using ozonation, identify the intermediates and byproducts of pyrene, and test the biodegradability of intermediates and byproducts of pyrene in the aqueous phase. Since pyrene is non-polar, hexane was chosen as a solvent to effectively dissolve pyrene. Pyrene solutions were treated with ozone, as it has high oxidation capacity and electrophilic characteristic. After different ozonation pretreatment times (2, 3, and 10 minutes), intermediates of pyrene in the form of yellowish solid were collected from the hexane solution using a centrifuge. They were identified by gas chromatography/mass spectrometer (GC/MS). $BOD_5$, COD, and E-coli toxicity tests have been performed to assess the ozonation products.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.58.2-58.2
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• 2018

Fossil groups of galaxies have characteristic features of a dominant central elliptical galaxy (${\Delta}M_{12}$ > 2 in $0.5R_{vir}$) embedded in highly relaxed X-ray halo, which indicates dynamically stable and evolved systems. These are thought as a final stage of the evolution of galaxy groups in the hierarchical structure formation scenario. However, the formation and evolution of fossil clusters are still unclear due to lack of detailed studies. Therefore, we perform a kinematic research of a known fossil cluster Abell 2261 (A2261 hereafter) using spectroscopic data of 589 galaxies in the A2261 field. Even though A2261 is known as a fossil cluster, previous studies found several unusual features such as quite high X-ray entropy for a stable cluster, and an elongated shape, which are not expected in standard fossil clusters. Using the caustic method, we identify cluster member galaxies and discover a second bright galaxy (${\Delta}M_{12}=1.68$) at ${\sim}1.5R_{vir}$. The presence of such a bright galaxy can break the current fossil state of cluster in the near future. In addition, with two independent substructure finding methods, we confirm that the previously detected elongated galaxy distribution of the cluster is a real feature. These findings indicate that A2261 is not in a fully stable state, unlike the existing fossil definition diagnostic. We require a more stringent criterion for the fossil definition to represent a genuinely final stage of cluster evolution.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.81-87
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• 2016

This paper analysis the AM-SCS-MMA (Adaptive Modulus-Soft Constraint Satisfaction-MMA) based on the adaptive modulus and minimus-disturbance technique in order to improve the stability and robustness in low signal to noise power of current MMA adaptive equalization algorithm. In AM-SCS-MMA, it updates the filter coefficient applying the adaptive modulus and minimum-disturbance technique of deterministic optimization problem instead of LMS or gradient descend algorithm for obtain the minimize the cost function of adaptive equalization. It is possible to improve the equalizer filter stability, robustness to the various noise characteristic and simultaneous reducing the intersymbol interference due to the amplitude and phase distortion occurred at channel. The computer simulation were performed for confirming the improved performance of SCS-MMA. For these, the output signal constellation of equalizer, residual isi, MSE, EMSE (Excess MSE) which means the channel traking capability and SER which means the robustness were applied. As a result of computer simulation, the AM-SCS-MMA have slow convergence time and less residual quantities after steady state, more good robustness in the poor signal to noise ratio, but poor in channel tracking capabilities was confirmed than MMA.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.1
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• pp.52-58
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• 2006

Single-electron transistor (SET)-based logic cells and SET/FET hybrid integrated circuits have been fabricated on SOI chips. The input-output voltage transfer characteristic of the SET-based complementary logic cell shows an inverting behavior where the output voltage gain is estimated to be about 1.2 at 4.2K. The SET/FET output driver, consisting of one SET and three FETs, yields a high voltage gain of 13 and power amplification with a wide-range output window for driving next circuit. Finally, the SET/FET literal gate for a multi-valued logic cell, comprising of an SET, an FET and a constant-current load, displays a periodic voltage output of high/low level multiple switching with a swing as high as 200mV. The multiple switching functionality of all the fabricated logic circuits could be enhanced by utilizing a side gate incorporated to each SET component to enable the phase control of Coulomb oscillations, which is one of the unique characteristics of the SET-based logic circuits.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.265-270
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• 2004

This paper addresses the effect of group delay in satellite communication system. Phase of signal is distorted by the non-constant group delay. Group delay can be modeled as linear, parabolic and cubic type according to the polynomial characteristic. We investigate BER performance of satellite communication system with each 3 kinds of group delay. As signal bandwidth becomes wider, group delay makes more influence on the signal. BNR performance of satellite communication system is found when data rates are 1Mbps, 4Mbps and 8Mbps. Convolution coding with the code rate of 1/2 or 7/8 is used. At BER =10$\^$-5/, system with group delay needs more SNR of minimum 0.3㏈ to maximum 4.4㏈ than system without group delay. The worst case of BER performance happens in the linear group delay, 7/8 punctured convolution coding and 8 Mbps. The required SNR is increased by 4.4㏈ at this worst case.