• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.1-9
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• 1990

The performance of noncoherent FH/FSK system in the presence of multitone jamming and noise is analyged. Random and the structured jammings are considered as a multitone jamming model. The probability density function is derived and then optimum decision rule is applied to determine error probability of each cases. As a result, error probabilities of random and structured multitone jamming are shown as a function of number of jamming tones, jamming to signal power ratio, jamming signal phase and one jamming tone power to signal power ratio under Worst-case Jamming interference. It is found that error probability is maximam when one jamming tone power to signal power ratio is 1. Also we know that error performance of random and structured jamming is almost equal.

• The Journal of Information Technology
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• v.9 no.4
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• pp.57-63
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• 2006

The intelligent elder brother groove network robot service the new broadband presence line is conversionce application service. Robot control data transmission hazard UDP packet of the remote control data which stands duplication necessary to transmit. TCP the error ratio to be high qualitative recording transmission pattern it of the transmission unit and is irregular the distance is distant to show and also the transmission lag is visible increases. The recording packet drop whose UDP degree error ratio will be high is frequent and does not arrive packet little by little increases is a possibility of knowing in the transmission unit. The technique which it proposes with traffic pattern of the transmission unit is visible the transfer characteristic of the same shape from 1% packet error ratio degree. The effective transmission technique of the robot control data which puts a base in UDP protocols was proposed from the present paper. Following research it leads and it follows the duplication transmission number of time in error rate of radio link and it was thought all that controls petty the research of the mechanism which progresses is necessary.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.11
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• pp.9-14
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• 2008

This paper presents the performance analysis of 10[Gb/s] optical duobinary transmitters with the non-ideal Mach-Zehnder modulator which does not have exactly 50/50 splitting/combining ratios by computer simulations. For driving voltage ratios(=driving voltage/switching voltage) with smaller than 100[%], the transmission performance has been greatly affected by extension of LPF bandwidths. Nevertheless, the performance has been degraded when the driving voltage ratio is 100[%]. The smaller driving voltage ratios has, the more sensitivity improves by extension of LPF bandwidths under the asymmetry condition. But the driving voltage ratio with 80[%] has better bit error rate(BER) than those with 50[%] and 25[%].

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.5
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• pp.217-221
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• 2005

A inductive voltage divider(IVD) is widely used as a ratio arm of precise impedance measurement bridges at low frequencies of audio frequency range and a well fabricated IVD has ratio error of $10^{-7}$ order without any calibration. Recently, the order of $10^{-8}$ of the best measurement uncertainty is needed for calibration and maintenance of impedance standards as national standards. In order to achieve that uncertainty, the IVD which is used for a ratio arm of precise impedance measurement bridge should be calibrated within the uncertain of order of $10^{-8}$ For this purpose, a ratio calibration bridge for IVDs has been developed. The measurement uncertainties of both inphase and quadrature of the bridge are analyzed less then $3{\times}10^{-8}$ respectively at 1 kHz and 25 V.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.27-33
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• 2001

In this study, it is observed that the distribution of combustion chamber volume affects the volumetric efficiency. The distribution ratio was adjusted by controlling combustion chamber volume of head and piston bowl one. Four cases were investigated, which are the combination of different distribution ratios and different compression ratios (9.8-10.0). A commercial SOHC 3-valve engine was modified by cutting the bottom face of the head and/or replacing the piston by the one that has different volume. The result shows that the less the head side volume, the more volumetric efficiency is achieved under the same compression ratio. It is also observed that increasing volumetric efficiency results in early knock occurrence due to increased "real" compression ratio. To consider reliability in estimating the volumetric efficiency, we examined the sensitivity of the AFR equation to possible errors in emission measurements. It is shown that the volumetric efficiency, which is calculated by measuring AFR and fuel consumption, can be controlled in 1% error. 1% error.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.380-386
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• 2019

In this paper, in order to compare the mixing ratio according to the feeding method, the input error of the main material and the sub material was measured and analyzed for 100 cycles using raw material having the same viscosity. As a result of the piston pump method, the input error of main material and sub material varied greatly from 0g to 3g, and the maximum error ratio was 10.3%. In the dual-screw rotation method, the input error varied from 0.01g to 0,4g, and the maximum error ratio was 0.41%, and almost no input error occurred. As the process cycle increased, it was found that the feed was almost uniform. The dual-screw rotary two-component mixing system was used to measure and analyze the inputs of the main and sub materials for 100 using three types of liquid silicones with different viscosities of the raw materials. As a result, the average error was 0.75g and the error rate was less than 1% regardless of the viscosity of the applied raw materials. When rae materials having the same viscosity were used, the average error ratio of the piston pump method was 4.09%.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.3
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• pp.66-72
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• 1984

In this paper, the error rate performance of L-level amplitude shift keying (ASK), M-ary phase shift keying (PSK) and amplitude phase keying (APK) systems have been studied in the presence of interference and noise. Using the derived error probability equations, the error rate performance of each L-level ASK and M-ary PSK system has been evaluated in terms of carrier-to-noise power ratio (CNR), carrier-to-interferer power ratio (CIR), and envelope distribution of interferer. These results are combined and then the error rate performance of APK signal has been found. Finally, the error rate performance is compared and discussed.

• ETRI Journal
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• v.31 no.1
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• pp.21-30
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• 2009

In low bit-rate video transmission, the payload of a single packet can often contain a whole coded frame due to the high compression ratio in both spatial and temporal domains of most modern video coders. Thus, the loss of a single packet not only causes the loss of a whole frame, but also produces error propagation into subsequent frames. In this paper, we propose a novel whole frame error concealment algorithm which reconstructs the first of the subsequent frames instead of the current lost frame to suppress the effects of error propagation. In the proposed algorithm, we impose a constraint which uses side match distortion (SMD) and overlapped region difference (ORD) to estimate motion vectors between the target reconstructed frame and its reference frame. SMD measures the spatial smoothness connection between a block and its neighboring blocks. ORD is defined as the difference between the correlated pixels which are predicted from one reference pixel. Experimental results show that the proposed algorithm effectively suppresses error propagation and significantly outperforms other conventional techniques in terms of both peak signal-to-noise ratio performance and subjective visual quality.

• International Journal of Control, Automation, and Systems
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• v.6 no.1
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• pp.54-61
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• 2008

This paper presents a method for reducing modelling error in the linear motion system with voicecoil actuator (VCA). A model of linear motion system composed of a mechanism and control was prepared to verify the proposed method. In modeling of the system, the damping coefficient obtained experimentally is applied to the model in order to consider the effect of the viscous friction for the moving part in VCA. The response velocity of VCA for duty ratio of PWM signal was analyzed in the time domain. Consequently, the relation between velocity and duty ratio was obtained. The result from the experiment showed an error of 9% when compared with that of simulation. In order to reduce the modeling error, impedance variation according to input frequency was analyzed, and equivalent impedance with multi-frequency was applied to the control part. As a result, the modeling error decreased to 5%.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.299-303
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• 2012

Purpose: In this study the correlation among the myopic refractive error and ocular components in primary school students was investigated. Methods: The subjects were 62 children who had no eye diseases. The refractive error, corneal radius, anterior chamber depth, lens thickness, axial length were measured and analysed. Results: Myopic refractive error in primary school students was negatively correlated with the axial length (1~3rd grade r=-0.653, p=0.000/4~6th grade r=-0.742, p=0.000), AL/CR ratio (1~3rd grade r=-0.571, p=0.000/4~6th grade r=-0.852, p=0.000). Conclusions: It was shown that the axial length and axial length(AL)/corneal radius(CR) ratio were very important data for myopic refractive error in primary school students.