• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.126-129
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• 1999

In this paper, it is assumed that a mobile radio channel is a Rayleigh distributed multipath fading channel and Erlang capacity and equivalent channel numbers are calculated for the reverse link of a imperfect power controlled DS/CDMA cellular system considering both shadowing and multipath fading. The DS/CDMA blocking probability is calculated based on a new analysis method that considers Erlang capacity and ICF(interference correction factor) using the median value of $E_{b(i)}$/ $I_{o}$ corresponding to each reverse link user. It is showed that the effect of multipath fading must not be ignored in Erlang capacity of the IS-95 DS/CDMA cellular system and the Erlang capacity is decreased according to the increase of the deviation of the imperfect power control, to the decrease of the processing gain, to the increase of the voice activity.y.

• KSTLE International Journal
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• 제1권1호
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• pp.59-62
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• 2000

This paper deals with an experimental study on the dynamic response of an elastomeric oil seal when the interferences between shaft and lip as well as the dynamic eccentricities are present. The dynamic response of seal lip in oil seals was observed with the aid of an image processing apparatus. The temperature of the seal lip edge, friction torque and the dynamic sealing gap between shaft and lip are measured at different conditions of the initial interference and the shaft eccentricity, The data were simultaneously measured under dynamic conditions. Experimental results show that, as the shaft speed is increased, S/e$_{d}$ has nearly reached a constant asymptotic value fur a certain range of shaft speeds. The results indicate that the gap separation between shaft and lip is provided due to the shaft eccentricity because the seal lip cannot follow quickly the radial displacements with increasing shaft speed.d.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.2891-2903
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• 2020

Phase-generated carrier (PGC) demodulation algorithm is the main demodulation methods in Fiber-optic interferometric sensors (FOISs). The conventional PGC demodulation algorithms are influenced by the carrier phase delay between the interference signal and the carrier signal. In this paper, an automatic carrier phase delay synchronization (CPDS) algorithm based on orthogonal phase-locked technique is proposed. The proposed algorithm can calculate the carrier phase delay value. Then the carrier phase delay can be compensated by adjusting the initial phase of the fundamental carrier and the second-harmonic carrier. The simulation results demonstrate the influence of the carrier phase delay on the demodulation performance. PGC-Arctan demodulation system based on CPDS algorithm is implemented on SoC. The experimental results show that the proposed algorithm is able to obtain and eliminate the carrier phase delay. In comparison to the conventional demodulation algorithm, the signal-to-noise and distortion ratio (SINAD) of the proposed algorithm increases 55.99dB.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.268-271
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• 2002

The goal of the research is to study and describe a new stressed state of High Temperature Superconducting (High-Tc) YBCO Films, to create of SQUIDs (Superconducting Quantum Interference Device) on the bases of these Films with maximal sensitivity. The experimental investigation of the stressed films grown by laser ablation method and its properties, the fabrication of the dc-SQUIDs with maximal sensitivity on the bases of the stressed YBCO films were carried out. The stressed film having the value of the critical current density $J_{c}=3{\cdot}10^{5}A/cm^{2}$ was the more stable than others.

• Mycobiology
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• 제44권2호
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• pp.67-78
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• 2016

Rice contaminated with fungal species during storage is not only of poor quality and low economic value, but may also have harmful effects on human and animal health. The predominant fungal species isolated from rice grains during storage belong to the genera Aspergillus and Penicillium. Some of these fungal species produce mycotoxins; they are responsible for adverse health effects in humans and animals, particularly Aspergillus flavus, which produces the extremely carcinogenic aflatoxins. Not surprisingly, there have been numerous attempts to devise safety procedure for the control of such harmful fungi and production of mycotoxins, including aflatoxins. This review provides information about fungal and mycotoxin contamination of stored rice grains, and microbe-based (biological) strategies to control grain fungi and mycotoxins. The latter will include information regarding attempts undertaken for mycotoxin (especially aflatoxin) bio-detoxification and microbial interference with the aflatoxin-biosynthetic pathway in the toxin-producing fungi.

• 한국CDE학회논문집
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• 제13권5호
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• pp.382-390
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• 2008

Five-axis machining has been applied to manufacture of turbine blades, impellers, marine propellers. Nowadays it extends to mold & die machining, where more productivity as well as added value is expected. The five-axis machining can be divided into positional and continuous, according to the variableness of tool orientation during material removal process. The positional five-axis machining is commonly applied to the regional machining on a whole part surface in mold manufacturing industry, where the tool orientation for each region (area) should be determined to be feasible, that is, avoiding any interference such as machine tool collision, etc. Therefore it is required for a CAM programmer to decide a feasible tool orientation in generating tool-paths on a designated area, because it is a very tedious job to obtain such information by utilizing a commercial CAM system. The developed system generates feasibility data on tool orientation and machining region, which facilitates the CAM programmer's decision on a feasible tool orientation.

• 음성과학
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• 제8권4호
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• pp.221-228
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• 2001

The purpose of this study is to analyze the problems Korean students, having acoustic structure of Korean vowels, have when they pronounce English vowels by measuring formant frequencies. The experimental results show that the pronunciation of English vowels by Korean students is partially influenced by their Korean vowels. There is little distinction between /i/ and /I/, /U/ and /u/ due to the absence of short and long vowels in Korean pronunciation. Also, as observed in typical Korean vowel pronunciation, there is little difference between the F1 values of /$\varepsilon$/ and /$\{\ae}$/ by Korean speakers, resulting in inaccurate English pronunciation. In addition, compared to English native speakers, Korean speakers show the biggest difference in F1 value of /c/. The fact that they make pronunciation of /c/ covering /e/, /$\Lambda$/ and /c/ positions probably accounts for such phenomenon. The results of this experiment show the interference of Korean that occurred in some English vowels by native Korean speakers.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.15-19
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• 2003

In this paper, the bit error rate (BER) performance of the fast frequency hopping/M-ary frequency shift keying system using the clipper receiver is analyzed by using the characteristic function (CF) technique in the presence of n=1 band multitone jamming and additive white Gaussian noise environment. The CFs of the clipper receiver outputs are derived as a infinite series representation using Gamma function and Marcum's Q -function. The analytical results are validated with various simulation results. Performance comparisons with linear combining receiver are shown that the BER performance of the clipper receiver is much better than that of the linear combining receiver In addition, as the clipping level approaches to infinity, it is shown that the clipper receiver simply performs a linear combining without clipping and there exists an optimum value of diversity level (the number of hops per symbol) that maximizes the worst case BER performance of the clipper receiver.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.59-64
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• 2001

The necessity of six axis force-torque sensors have been increased in the field of automatic assembly, polishing and deburing using robotic manipulator recently. This paper presents a simple and compact elastic structure design of the six axis force-torque sensor with a cross-shaped structure and the expected deflection value was induced by theoretical method to design a six axis force-torque sensor and then this theoretical method was verified by comparing with the results using the Finite Element Method(FEM).

• ETRI Journal
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• 제29권5호
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• pp.607-613
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• 2007

Most signal-to-noise ratio (SNR) estimation techniques in digital communication channels derive the SNR estimates solely from samples of the received signal after the matched filter. They are based on symbol SNR and assume perfect synchronization and intersymbol interference (ISI)-free symbols. In severe channel distortion where ISI is significant, the performance of these estimators badly deteriorates. We propose an SNR estimator which can operate on data samples collected at the front-end of a receiver or at the input to the decision device. This will relax the restrictions over channel distortions and help extend the application of SNR estimators beyond system monitoring. The proposed estimator uses the characteristics of the second order moments of the additive white Gaussian noise digital communication channel and a linear predictor based on the modified-covariance algorithm in estimating the SNR value. The performance of the proposed technique is investigated and compared with other in-service SNR estimators in digital communication channels. The simulated performance is also compared to the Cram$\acute{e}$r-Rao bound as derived at the input of the decision circuit.