• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.193-200
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• 2006

The purpose of this study is to compare the part-load performance of a SOFC/GT hybrid power system with three different kinds of load-following operation modes. The primary mode for the part load operation of a hybrid power system is the reduction of supplied fuel (e.g., fuel control mode) to the hybrid system. The other two options, i.e., variable speed and VIGV controls, are related to the reduction of supplied air simultaneously with the reduction of supplied fuel to the system. With the performance analysis of a SOFC/GT hybrid power system, it is concluded that the variable speed con佐ol mode Provides the best performance for the part-load operations. It is also found that the VIGV control mode, with its better performance behavior than the fuel control mode, can be used as an important option for the part-load operation especially in case that the variable speed control mode can not be adopted.

• Science of Emotion and Sensibility
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• v.17 no.4
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• pp.51-60
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• 2014

This double-blind study, as a human experiment of nonlocality, investigated the effects of senders' intention on the central nervous system of a distant human receiver and it explored the roles that motivation might have in modulating these effects. Whole brain activity was measured in the receiver whom was asked to relax in a distant room for 16 minutes; the sending person directed intention of oneness toward the receiver during repeated variable-second epochs separated by variable-second non-intention epochs. The total length of intention epochs and that of nonintention epochs were balanced. Eighteen sessions were conducted. In 9 of those sessions, the sender was the receiver's lover. In another 9 of those sessions, the sender was just acquainted with the receiver before the session. The receiver's whole brain activity recorded during the intention epochs were compared with the same measures recorded during the nonintention epochs used as controls. The statistical difference between the intentions versus controls across 18 sessions was examined by paired-t test. In addition, subgroup analysis for the 9 couple sessions and 9 non-couple sessions were additionally examined by the same test. The effect of distant intentionality decreased slow waves or increased EEG fast waves mainly in frontal regions, and increased EEG coherence during the intention epochs. The effects was not statistically significant after Bonferroni correction, but the couple sessions combined showed the largest effect followed by all sessions combined. Non-couple sessions combined showed the smallest effect. The changes in EEG power mean that receiver participants became more alert during the intention epochs and the change in EEG coherence might be evidence of coherent heart influence on EEG activity. Planned comparison with specific hypothesis testing for the suggested changes in this study have to be followed for an evidence of electroencephalographic changes in isolated subjects for the distant mental intention.

• The Journal of the Acoustical Society of Korea
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• v.23 no.6
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• pp.446-453
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• 2004

In this paper, a new adaptive perceptual filter using variable threshold to enhance audio signals degraded by additively nonstationary noise is proposed. The adaptive perceptual filter updates variable threshold each time according to the power of signal and the effect of noise variation. So the noisy audio signal is enhanced by the method which controls a residual noise effectively. The proposed algorithm uses the perceptual filter which transforms a time domain signal into frequency domain and calculates an intensity energy and an excitation energy in bark domain. In this method. the stage updated the response of filter is decided by threshold. The proposed algorithm using vairable threshold effectively controls a residual noise using the energy difference of audio signals degraded by the additive nonstationary noise. The proposed method is tested with the noisy audio signals degraded by nonstationary noise at various signal -to-noise ratios (SNR). We carry out NMR and MOS test when the input SNR is 15dB. 20dB. 25dB and 30dB. An approximate improvement of 17.4dB. 15.3dB, 12.8dB. 9.8dB in NMR and enhancement of 2.9, 2.5, 2.3, 1.7 in MOS test is achieved with the input signals. respectively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.430-440
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• 2011

The purpose of this study was to investigate the interactions between the thermal factors in existing thermal control methods and to find out the control logic that can create more comfortable thermal conditions. For it, four thermal control logics were developed：conventional temperature-based control; temperature-based and humidity-based control; PMV-based control; and TS-based control. Their performance was comparatively tested in the U.S. typical 5-story office building in two climate zones (Detroit, Michigan and Miami, Florida) for two seasons (winter and summer) incorporating IBPT (International Building Physics Toolbox) and Matlab/Simulink. Analysis on the thermal conditions and energy efficiency revealed that each control logic created comfortable conditions for their respective target, i.e., temperature, humidity, PMV or TS, but uncomfortable for others (e.g., temperature-based control logic maintained PMV or TS uncomfortably or vise versa). In addition, energy efficiency was significantly different by logics. In conclusion, it can be said that the overall thermal comfort can be improved by the adoption of the PMV and TS as a target variable and their economical benefits are expected in the hotter climate zones with the reduced cooling and dehumidifying energy consumptions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.931-940
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• 2001

In this paper, I propose Fuzzy Policing Mechanism(FPM) over ATM networks for the control of traffic which is unpredictable and bursty source. The FPM is consist of counter, subtracter and Fuzzy Logic Controller(FLC). The FLC is divided to fuzzifier, inference engine and defuzzifer The output of FLC inputs to the subtractor and it controls the counter. The counter works as a switch in transmission of cells. In simulation, I compared the FPM with the Leaky Bucket algorithm(LBM) in cell loss probability and performance characteristics. As a result, FPM gives lower cell loss probability than that of LBM and has good response behavior The FPM efficiently controls the transmission of packets which are variable traffic source and, it also has good selectivity.

• Childhood Kidney Diseases
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• v.20 no.1
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• pp.23-28
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• 2016

Purpose: We investigated whether serum levels of insulin growth factor-1 (IGF-1) and insulin growth factor binding protein-3 (IGFBP-3) are valuable in predicting clinical outcomes or are correlated with other laboratory findings in children with Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP). Methods: We examined 27 children who were consecutively admitted to our hospital with HSP between January 2011 and February 2012. Blood tests (C-reactive protein, white blood cell count, platelet count, erythrocyte sedimentation rate, albumin, immunoglobulin A, complement C3, antineutrophil cytoplasmic antibody, IGF-1, IGFBP-3) and urine tests were performed upon admission. IGF-1 and IGFBP-3 were resampled in the recovery phase. Controls included 473 children whose IGF-1 and IGFBP-3 were sampled for evaluating their growth, at the outpatient department of pediatric endocrinology in our hospital. IGF-1 and IGFBP-3 were compared between the HSP children and controls, and between the acute and recovery phases in HSP children. The ability of these values to predict clinical outcomes including renal involvement was analyzed using bivariate logistic regression analysis (BLRA). Results: IGF-1 and IGFBP-3 were not different between the HSP children and controls ($148.7{\pm}117.6$ vs. $69.2{\pm}96.9$, P=0.290: $3465.9{\pm}1290.9$ vs. $3597.2{\pm}1,127.6$, P=0.560, respectively). There was no significant difference in IGF-1 or IGFBP-3 between acute and recovery phases. Based on the BLRA, no variable, including IGF-1 and IGFBP-3, could predict clinical outcomes including the presence of nephritis Conclusion: We concluded that IGF-1 and IGFBP-3 do not predict clinical outcomes of HSP, including renal involvement, in this study.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.10
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• pp.910-916
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• 2015

A sensorless motor control scheme with conventional back-Electro Motive Force (EMF) sensing based on zero crossing point (ZCP) detection has been widely used in various applications. However, there are several problems with the conventional method for effectively driving sensorless brushless motors. For example, a phase mismatch of 30 degrees occurs between the ZCP and commutation time. Additionally, most of the motor speed/current controls are achieved based on a pulse width modulation (PWM) method, which generates significant noise that distracts the back-EMF sensing. Due to the PWM switching, the ZCP is not deterministic, and thus the efficiency of the motor is reduced because the phase transition points become uncertain. Moreover, the motor driving performance is degraded at a low speed range due to the effect of PWM noise. To solve these problems, an improved back-EMF detection method based on a differential line method is proposed in this paper. In addition, the proposed sensorless BLDC driver addresses the problems by using a variable voltage driver generated from a buck converter. The variable voltage driver does not generate the PWM switching noise. Consequently, the proposed sensorless motor driver improves 1) the signal-to-noise ratio of back-EMF, 2) the operation range of a BLDC motor, and 3) the torque characteristics. The proposed sensorless motor driver is verified through simulations and experiments.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.410-416
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• 2003

In the affine projection algorithm(APA), the projection dimension depends on a number of projection basis and of elements of input vector used for updating of coefficients of the adaptive filter. The projection dimension is closely related to a convergence speed of the APA, and it determines computational complexity. As the adaptive filter approaches to steady state, convergence speed is decreased. Therefore it is possible to reduce projection dimension that determines convergence speed. In this paper, we proposed the variable dimension affine projection algorithm (VDAPA) that controls the projection dimension and uses the relation between variations of coefficients of the adaptive filter and convergence speed of the APA. The proposed method reduces computational complexity of the APA by modifying the number of projection basis on convergence state. For demonstrating the good performances of the proposed method, simulation results are compared with the APA and normalized LMS algorithm in convergence speed and computational quantity.

• IMMUNE NETWORK
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• v.3 no.3
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• pp.242-247
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• 2003

Background: Psoriasis is an inflammatory skin disorder that is characterized by a marked proliferation of keratinocytes, vascular dilation and leukocyte infiltration. Cytokines play important roles in the pathogenesis of inflammatory disorders. An overexpression of proinflammatory cytokines was characterized in psoriasis plaque. Among these cytokines, IL-$1{\beta}$ is major pro-inflammatory cytokine synthesized during the infection and inflammatory process. The IL-1 receptor antagonist (IL-1Ra) competes for the same IL-1 receptor for $IL-1{\alpha}$ and $-1{\beta}$, which prevents activation of the target cells. Three single nucleotide polymorphisms (SNPs) in the IL-$1{\beta}$ gene have been reported at position -31, -511 and +3954. Within the IL-1Ra gene (IL-1RN), there is a variable number of tandem repeats (VNTR) of an 86 bp length in intron 2. These polymorphisms related to cytokine production and associated with various diseases. Methods: We investigated the polymorphisms of IL-1B (promoter -511 and +3954) and IL-1RN on 114 psoriasis patients and 311 healthy normal controls in Korean. We performed PCR-RFLP on single nucleotide polymorphisms (SNPs) of IL-1B (promoter -511 and +3954) and fragment analysis on IL-1RN 86 bp VNTR polymorphism. Results: The frequency of IL-1B $-511^*1$ allele (patients vs. controls; 50.0% vs. 42.3%, RR=1.4) was significantly increased and IL-1B $-511^*2$ allele (patients vs. controls; 50.0% vs. 57.7%, RR=0.7) decreased in psoriasis patients compared to normal controls. We also analyzed the IL-1B -511 polymorphism according to patients' characters (age of onset, sex and family history). The IL-1B -511 alleles were significantly associated in patients with male and family history than health normal controls. There were no significant associations of IL-1B +3954 and IL-1RN polymorphisms with psoriasis patients. Conclusion: These results suggest that the polymorphism of IL-1B -511 could be genetic susceptibility to psoriasis in Koreans.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.2
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• pp.123-130
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• 2013

Autonomous agricultural machines that are operated in small-scale farmland frequently experience turning and changes in direction. Thus, unlike when they are operated in large-scale farmland, the steering control systems need to be controlled precisely so that travel errors can be minimized. This study aims to develop a control algorithm for improving the path tracking performance of a steering system by analyzing the effect of the setting of the waypoint, which serves as the reference point for steering when an autonomous agricultural machine moves along a path or a coordinate, on control errors. A simulation was performed by modeling a 26-hp tractor steering system and by applying the equations of motion of a tractor, with the use of a computer. Path tracking errors could be reduced using an algorithm which sets the waypoint for steering on a travel path depending on the radius of curvature of the path and which then controls the speed and steering angle of the vehicle, rather than by changing the steering speed or steering ratio which are dependent on mechanical performance.