• Journal of the Korean Institute of Landscape Architecture
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• v.20 no.3
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• pp.93-102
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• 1992

This study was carried out to estimate the recreation carrying capacity of lawn areas in parks. Recreation carrying capacity in this study is composed of two parts, ecological carrying capacity. This part deals with the psychological carrying capacity, based on the perception of crowding level and recreation satisfaction of users. The survey was conducted at the lawn areas of Doturag World and Seorabul Plaza in Bomun Resort Complex in Kyungju. The major results are as follows: 1. As the result of regression of regression analysis between use density of lawn area and level of perceived crowding, the capacity was estimated as 60.0㎡ man. 2. As the result of regression analysis between use density of lawn areas and total recreation satisfaction, the capacity was estimated as 48.5㎡/man. 3. As the result of regression analysis between use density of lawn areas and satisfaction to use density, the capacity was estimated as 63.2㎡/man. 4. As a conclusion, the psychological carrying capacity was estimated as 60.0㎡/man. And this value is based on user's perception of crowding and recreation satisfaction level for each use densities.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.247-254
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• 2004

The mechanical informations such as the rotor speed and angle are required to operate the Cylindrical Permanent Magnet Synchronous Motor(PMSM). A resolver or encoder is typically used to supply the mechanical informations. This position sensor adds length to the machine, raises system cost, increases rotor inertia and requires additional devices. As the result, there has been a significant interest in the development of sensorless strategies to eliminate the position sensor. This paper presents an implementation of the new sensorless speed comtrol scheme for a PMSM. In the proposed algorithm, the line currents are estimated by a observer and the estimated speed can be yielded from the voltage equation because the information of speed is included in back emf. But the speed estimation error between the estimated and the real speeds is occured by errors due to measuring the motor parameters and sensing the line current and the input voltage. To minimize the speed estimations error, the estimated speeds are compensated by using an instantaneous reactive power in synchronously rotating reference frame. In this paper, the proposed algorithm is not affected by mechanical motor parameters because the mechanical equation is not used. The effectiveness of algorithm is confirmed by the experiments.

• Journal of the Korean Society of Costume
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• v.55 no.1 s.91
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• pp.139-150
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• 2005

The purpose of this study was to find out differences of image evaluation according to perceiver's gender and clothing style, and to investigate the clothing preference according to the style of campus wear. Subjects were 340 college males and females in Seoul. The image of campus wear was divided into four dimensions: neatness, polishing, potency, and activity. Gender had significant influences on the perception of neatness, polishing, and potency. Males perceived the campus wear to be neater, more polished and potent than females. There were significant differences in evaluating neatness, polishing, potency, and activity according to campus wear style. The sweatshirt was estimated low in polishing and potency but high in activity. The T-shirt${\cdot}$short pants was estimated low in polishing and neatness but high in activity. The jumper was rated high in activity, and pants suit high in neatness, polishing, and potency, but it was estimated low in activity. The skirt suit was rated high in neatness and low in activity. The knit cardigan was perceived as polished image. College students preferred knit cardigan, one-piece dress, jumper, and pants suit, however, T-shirt${\cdot}$short pants was comparatively less preferred. Males estimated the knit cardigan to be more favorable than females. Characteristics of clothing image which influenced on preference of campus wear were different between males and females.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.57-64
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• 2000

In order to regulate cutting torque in milling, monitoring system should be set to a certain threshold. Radial immersion ratio is an important factor to determine the threshold and should be estimated in process for automatic regulation. In this paper, on-line estimation of the radial immersion ratio using spindle motor current in face milling is presented. When a tooth finishes sweeping, a sudden drop of cutting torque occurs. This torque drop is equal to the cutting torque acting on a single tooth at the swept angle of cut and can be acquired from cutting torque signals. Average cutting torque per revolution can also be calculated from cutting torque signals. The ratio of cutting torque acting on a single tooth at the swept angle of cut to the average cutting torque per revolution is a function of the swept angle of cut and the number of teeth. Using the magnitude of this ratio, the radial immersion ratio is estimated. Identical algorithm is adopted to estimate the immersion ratio based on the spindle motor current measurement. The experiments performed under different cutting conditions show that the radial immersion ratio can be estimated within 10% error range by the proposed method using spindle motor current. Varying immersion ratio is also estimated well using the presented algorithm.

• Animal cells and systems
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• v.14 no.4
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• pp.291-296
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• 2010

Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients ($q_t$). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The $q_t$ for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the $q_t$ was taken into account. The mortality coefficient, survival rate, $q_t$ and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

• Journal of Environmental Science International
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• v.23 no.4
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• pp.605-613
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• 2014

In this work, the delay time for groundwater recharge was estimated by comparing simulated recharges by means of SWAT(Soil and Water Assessment Tool) model and WTF(Water Table Fluctuation) method. The delay time for groundwater recharge means that the time when the water from rainfall travelled through vadose zone just after getting out of soil zone bottom. As measuring this delay time is almost impossible, we used to compare the estimated values from modeling(SWAT) and analytic method(WTF). The test site is Hancheon watershed which has 8 groundwater measurement stations. The results show that the altitude has a linear relationship with the estimated delay time values. To validate these results, we conducted corelation analysis between transformed groundwater levels and observed ones. The results showed that computed groundwater levels have good corelation($R^2$=0.97, 0.87, respectively). The estimated delay time would be used for the groundwater behaviour characteristics in vadose zone. As recharge rates vary according to the height, the delay time is thought to be an import variable for the proper groundwater recharge estimation.

• KDI Journal of Economic Policy
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• v.36 no.2
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• pp.1-64
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• 2014

This paper attempts to search the driving forces of the Korean economy after 2000 by analyzing an estimated DSGE model and observing the degree of implementation regarding non-systematic parts of both the monetary and fiscal policy during the global financial crisis. Two types of trends, various cyclical factors and frictions are introduced in the model for an empirical analysis in which historical decompositions of key macro variables are quantitatively assessed after 2000. While the monetary policy during the global financial crisis have reacted systematically in accordance with the estimated Taylor rule relatively, the fiscal policy which was aggressively expansionary is not fully explained by the estimated fiscal rule but more by the large magnitude of non-systematic reaction.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.120-129
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• 2004

Urban stream restoration projects can improve water quality, wildlife habitats, urban landscape, outdoor recreation spaces, and urban microclimate. The objectives of this research were to investigate temperature cooling effect of urban streams by using satellite imagery, to evaluate environmental variables related to stream cooling effect, and to estimate the cooling effect of the Cheonggye stream restoration project of Seoul, Korea. Findings of this research can be summarized as follows. First, a method of estimating temperature distribution around urban streams by using satellite imagery was developed. Scatter plots of distance from stream edges and average temperature obtained through multiple buffering were used for the estimation. Second, urban temperature cooling effect of streams was estimated by comparing background temperature and temperature of each buffer zone. Third, environmental factors affecting stream cooling effect were also identified. Fourth, the temperature cooling effect of the restoration project was estimated based on three scenarios. An estimated cooling effect based on the average cooling effect of existing tributaries showed the most significant effect; $2.0^{\circ}C$ lower than the present level at the edge of the renovated stream. It was estimated that the temperature of the same area would be $1.4^{\circ}C$ cooler than the present level if the cooling effect of the Yangjaechun was used as the bench mark But the effect would be $1.2^{\circ}C$ lower than the present level if environmental variables related to the temperature cooling effect of urban streams were used as the bench mark.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.288-290
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• 2005

Deicing system operated in high speed line is to melt frost or ice freezed in catenary line when the temperature is lower than 0 in winter. The principle of deicing system is to m디t frost or ice by Joule heat of catenary impedance. The performance of deicing is dependant of deicing current determined by the length of deicing section, deicing impedance and current division ratio of catenary line and messenger line. So, We present technique for estimating deicing current in convention line. Deicing impedance is estimated using Carson - Pollaczek, current division ratio of catenary line and messenger line is estimated using voltage drop, and deicing current is estimated using power system data of operation secion for deicing system in this technique. To verify the validity of technique, we compare the estimated current using technique of this paper with deicng current of high speed line.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.287-292
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• 2005

This paper presents a rational polynomial approximation method to estimate modal parameters of wind excited structures using incomplete noisy measurements of structural responses and partial measurements of wind velocities only. A stochastic model of the excitation wind force acting on the structure is estimated from partial measurements of wind velocities. Then the transfer functions of the structure are approximated as rational polynomial functions. From the poles and zeros of the estimated rational polynomial functions, the modal parameters, such as natural frequencies, damping ratios, and mode shapes are extracted. Since the frequency characteristics of wind forces acting on structures can be assumed as a smooth Gaussian process especially around the natural frequencies of the structures according to the central limit theorem (Brillinger, 1969; Yaglom, 1987), the estimated modal parameters are robust and reliable with respect to the assumed stochastic input models. To verify the proposed method, the modal parameters of a TV transmission tower excited by gust wind are estimated. Comparison study with the results of other researchers shows the efficacy of the suggested method.