• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1448-1458
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• 1997

In this paper the reverse link of the GLOBALSTAR-the representative CDMA LEO satellite system and LEO mobile satellite channel are developed by the SPW software simulation tool. And the performance of the system is evaluated. GLOBALSTAR is designed to give cellular-type service to hand-held user terminals through a constellation of 48 LEO satellites in circular orbites with 1414 Km altitude. Since LEO mobile satellite system communicates with mobile unit, it is suffered from severe multipath fading and shadowing. The fast mobility of LEO satellites makes the channel condition time vering. So, the LEO mobile satellite channel is different from land mobile channels. In this unique LEO satellite channel, it is shown that the performance of the GLOBALSTAR reverse link is varied according to the elevational angle, but this variation is overcome by satellite path diversity.

• Journal of the Korean Home Economics Association
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• v.33 no.3
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• pp.59-70
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• 1995

This paper is to introduce cybernetic epistemology, which is one of the nonlinear or circular epistemology and have provided the basis for the development of various theories and models of family therapy. First, the history and the concept of the term cybernetics is briefly described, and then cybernetics is compared with general systems theory. following is the discussion of different levels of cybernetics, i.e., simple cybernetics and cybernetics of cybernetics, and of their major concepts, respectively. the ways in which cybernetic epistemology is applied to family therapy are also discussed in terms of diagnosis of problems, unit of therapy, goal of therapy, and role of family therapist. Finally, some implications for training and educating cybernetic family therapist are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.8
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• pp.2053-2067
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• 2023

This paper proposes two video quality assessment methods based on deep neural network. (i)The first method uses the IQF-CNN (convolution neural network based on image quality features) to build image quality assessment method. The LIVE image database is used to test this method, the experiment show that it is effective. Therefore, this method is extended to the video quality assessment. At first every image frame of video is predicted, next the relationship between different image frames are analyzed by the hysteresis function and different window function to improve the accuracy of video quality assessment. (ii)The second method proposes a video quality assessment method based on convolution neural network (CNN) and gated circular unit network (GRU). First, the spatial features of video frames are extracted using CNN network, next the temporal features of the video frame using GRU network. Finally the extracted temporal and spatial features are analyzed by full connection layer of CNN network to obtain the video quality assessment score. All the above proposed methods are verified on the video databases, and compared with other methods.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.75-86
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• 1996

In this paper, we propose a new fuzzy-neural network control scheme for the speed and azimuth control of a mobile robot. The proposed control scheme uses a gaussian function as a unit function in the fuzzy-neural network, and back propagation algorithm to train the fuzzy-neural network controller in the frame-work of the specialized learning architecture. It is proposed a learning controller consisting of two fuzzy-neural networks based on independent reasoning and a connection net woth fixed weights to simply the fuzzy-neural network. The effectiveness of the proposed controller is illustrated by performing the computer simulation for a circular trajectory tracking of a mobile robot driven by two independent wheels.

• Journal of Biosystems Engineering
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• v.8 no.2
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• pp.18-25
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• 1983

The binders introduced in Korea were originally designed to be used for Japonica varieties which have realtively long stem and are highly resistant to shattering. In order to use it for Tongil varieties which are short and easy to be shattered, mechanical modifications are necessary to reduce a grain loss incurred during its operation. This study was intended to investigate the binding unit, one of the major factors affecting grain losses. The binding parts of three binders used in Korea were analyzed and the grain loss was experimentally assessed for these binders. The results obtained from this study are summarized as follows: 1. From the motion analysis of discharge mechanism, the trajectory of the discharge arm appeared to be either circular or skewed elliptic. The velocity of a circular path mechanism was constant and smaller than that of a skewed elliptic path mechanism. The discharge grain loss of the former was about twice less than that of the latter. 2. It was found that the grain loss incurred due to the collision of the paddy bundles and ground was considerably high for Tongil varieties. The auxiliary discharge bar gave a significant influence on the motion and posture of the bundles, and the degree of impact on ground. 3. The installation of an auxiliary bar, which guides the paddy bundles smoothly to ground in order to reduce impact when the bundles fall down on ground, appeared to be very effective since the grain losses could be decreased by about 1.6 percentage point. However, the guide bar should be installed after some mechanical modification to reduce the velocity of discharge arm has been made.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.86-91
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• 2016

Convenient design guideline for Waveguide-below-cutoff (WBC) array is proposed to obtain the minimum waveguide length for electromagnetic pulse (EMP) shielding. The analysis includes circular, rectangular, and hexagonal WBC, determine the total length of the waveguide. When the unit side of rectangular WBC and the diagonal line of hexagonal WBC are given as 30 mm, the length of hexagonal WBC is 5 mm shorter than rectangular case with shielding effectiveness (SE) 80 dB. The length difference is deepened with SE of 100 dB, which shows approximately 30 mm shorter length for hexagonal case than others. In addition, hexagonal WBC requires much shorter length than circular WBC. In conclusion, hexagonal case is the most effective with respect to flow velocity and pressure loss for equivalent SE.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2427-2433
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• 2015

A high-gain circularly-polarized patch antenna with a double-layered superstrate is proposed operating at a wireless LAN frequency. A superstrate has an array of metallic periodic unit cells and is located above the patch antenna with an air-gap. The designed antenna has a high gain of over 9.59dBi, which is the gain enhancement of 6.48dB compared to the patch antenna without superstrate. And it has a low axial ratio of under 3dB, so that it maintains the circular polarization of the patch antenna. The optimum air-gap height at the superstrate of $4{\times}4$ arrays is 25mm, which is equivalent to about $0.2{\lambda}$ at the frequency of 2.45GHz. We confirmed that the double-layered stacking of a superstrate increases the effective aperture size and hence it leads to enhance a gain of the patch antenna.

• BMB Reports
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• v.41 no.1
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• pp.62-67
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• 2008

The present study was aimed to elucidate the mechanism of stabilization of tubulin by deuterium oxide ($D_2O$). Rate of decrease of tryptophan fluorescence during aging of tubulin at 4$^{\circ}C$ and 37$^{\circ}C$ was significantly lower in $D_2O$ than in $H_2O$. Circular dichroism spectra of tubulin after incubation at 4$^{\circ}C$, suggested that complete stabilization of the secondary structure in D2O during the first 24 hours of incubation. The number of available cysteine measured by DTNB reaction was decreased to a lesser extent in $D_2O$ than in $H_2O$. . During the increase in temperature of tubulin, the rate of decrease of fluorescence at 335 nm and change of CD value at 222 nm was lesser in $D_2O$. Differential Scanning calorimetric experiments showed that the $T_m$ values for tubulin unfolding in $D_2O$ were 58.6$^{\circ}C$ and 62.17$^{\circ}C$, and in $H_2O$. those values were 55.4$^{\circ}C$ and 59.35$^{\circ}C$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.1
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• pp.1-7
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• 1990

Theoretical evaluations of the vertical displacement at the epicenter on the circular glass plate have been carried out in the case of the unit point loading(1 dyne force strength) with the Heaviside step-function time dependency. Acoustic emission signals generated during pencil lead($\Phi$=0.5mm, HB) fracture on the soda-lime glass($\Phi$=22cm, thickness=2.8cm) were observed by the optical Michelson interferometer with the stabilized circuit, and then the source function of the observed acoustic emission signals was analyzed by the deconvolution method. The source function of acoustic emission during pencil lead fracture had a 'dip' of~0.7$\mu$sec duration time at the front portion and a step function of~0.5$\mu$sec rise time with a force strength of~4.5N.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.34-42
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• 2001

A battery is the device that transforms the chemical energy into the direct-current electrical energy directly without a mechanical process. Unit cells are connected in series to obtain the required voltage, while being connected in parallel to organize capacity for load current and to decrease the internal resistance for corresponding the sudden shift of the load current. Because the voltage droop down in one set of battery is faster than in tow one, it amy result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However, when the system being driven in parallel, a circular-current can be generated. The changing current differs in each set of battery because the system including batteries, rectifiers and loads is connected in parallel and it makes the charge voltage constant. It is shown that, as a result the new batteries are heated by over-charge and over-discharge, and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper, we can detect the unbalance current using the micro-processor and achieve the balance current by adjusting resistance of each set. The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.