• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.50 no.2
• /
• pp.65-71
• /
• 2001

The step response of the Manabe standard form[2] has little overshoot and show almost same waveforms regardless of the order of the characteristic polynomials. In some situations it is difficult to control the rise time and settling time simultaneously of the step response of the Manabe standard form To control its rise time and settling time efficiently, We develop the Manabe standard form: We try to find out the SRFS(Slow Rise time & Fast Setting time) form which has the slower rise time and faster settling time than those fo the Manabe standard form. We also consider the other three forms: FRSS(Fast Rise time & Slow Settling time), SRFS(Slow Rise time & Fast Settling time) and SRSS(Slow Rise time & Slow Settling time) forms. In this paper, by using the evolutionary strategy, we obtain all the coefficient of the four forms we mention above. Finally, we design a controller for a given plant so that the overall system has the performance that the rise time is faster, the settling time is faster than those of the Manabe standard form.

• 연구논문집
• /
• s.34
• /
• pp.139-146
• /
• 2004

In this study, effect of temperature and time on melt-out of 25wt% Al-alloyed ductile iron has been investigated. The oxidation tests were carried out in a tube furnace at $800^\circC$, $930^\circC$, and $1000^\circC$ for lh, 5h, 10h, 50h. The microstructure, microhardness, and $Al_2O_3$ layer of oxidation-treated 25wt% Al-alloyed ductile iron samples (10 x 10 x 10 mm) were investigated. Phase identification was performed by X-ray diffraction(XRD) and EDS. The oxidation-treated 25wt% Al-alloyed ductile iron samples at $930^\circC$ for lh, 5h, 10h and KS GCD 500 were used for melt-out test in an Al alloy melt. The melt-out test results showed that oxidation tested sample at $930^\circC$ for 5h which on the whole forms $2-3\mum$ $Al_2O_3$ layer showed lowest melt-out depth. It was observed showed that appropriate Al203 layer can affect melt-out behaviors.

• Journal of the Korean Home Economics Association
• /
• v.27 no.4
• /
• pp.51-58
• /
• 1989

The purpose of this study was to investigate the state of eating out and the food preference of college students in Seoul. This survey was carried out through questionaires, and the subjects were 158 male and 159 female students. The results obttained were summarized as follows; 1) Students who took late evening meal at home after eating out were 35.7% and most of the reasons were to custom. 2) During eating out, 30% of students had drinking. Male students had Soju (45.6%), and female had Beer (56.0%). 3) The most cases in date time, eating out cost were 5,000w. They were fond of Western Restaurant and the favorite food were Dongas. 4) Freqency of eating out with family had more than once a month (35%), because of a memorial day and event day, and the most favorite food was Sogalbigui. 5) Male and female students's choice in food at restaurant type were very different.

• Journal of the Korean Home Economics Association
• /
• v.27 no.2
• /
• pp.65-74
• /
• 1989

The purpose of this study was to investigate the state of eating out and the food preference of college students in Seoul. This survey was carried out through questionaires, and the subjects were 158 male and 159 female students. The result obtained were summarized as follows; 1) Female students had more regular breakfast than male students, and male students had more regular dinner than female students. 2) Male and higher grade students brought home-made lunches more frequently than female students, and others ate out in campus dinning room and off campus dinning room. 3) Most of subjects (77.3%) ate out more than once a day, they ate out in lunch time more frequently than other times. 4) Male and female students used different type of restaurant. 5) The most favorite food of male students in eating out was a Dongas, and that of female students was Nangmyun.

• Journal of Families and Better Life
• /
• v.11 no.2
• /
• pp.83-95
• /
• 1993

This study investigated time management behavior of employed wives and variables related. The samples were composed of 396 wives living in Seoul and Kwangju city. The major finding are as follow: 1) The level of the time management of employed wives was slightly high. 2) The dominant factor in time management behavior was goal setting and planning$.$priori-ting 3) The time management behavior was low related to the time use. A negative relationship was found between time management behavior and psysiological time employed time psysical housework time and passive leisure time while a positive relationship was found managerial housework time and active leisure time 4) A employed wife with higher work status education and income level efficiently managed time Education and extend family type turned out facilitating factors the more employed time was found constraint factor in time management.

• 제어로봇시스템학회:학술대회논문집
• /
• 1999.10a
• /
• pp.116-120
• /
• 1999

The step response of the Manabe standard form[1］has little overshoot and shows almost same waveforms regardless of the order of the characteristic polynomials. In some situations it is difficult to control the rise time and settling time simultaneously of the step response of the Manabe standard form. To control its rise time and settling time efficiently, we develop the generalization of the Manabe standard form: we try to find out the SRFS(Slow Rise time & Fast Settling time) form which has the slower rise time and faster settling time than those of the Manabe standard form. we also consider the other three forms: FRSS(Fast Rise time & Slow Settling time), SRFS(Slow Rise time ＆ Fast Settling time) and SRSS(Slow Rise time & Slow Settling time) forms. In this paper, by using the genetic algorithm, we obtain all the coefficient of the four forms we mention above. Finally, we design a controller for a given plant so that the overall system has the performance that the rise time is faster, the settling time is slower than those of the Manabe standard form.

• Korean Institute of Interior Design Journal
• /
• v.24 no.6
• /
• pp.145-153
• /
• 2015

For this research with the objects of spaces in two department stores which can be referred to as representative facility of commercial space, observation test has carried out to estimate how much visitors rivet their eyes to the display of shops. In addition, to find out what effect the difference among the department types has on the selective attention to space element, the observation time was applied as a medium for estimation. The followings are the result from analyzing the observation frequency and the observation intensity feature of each section where the characteristics of design could be found at attention. First, both images of A and B had concentrative dominant-observation at left shops. In case of Image A, Customers began to observe the right shops very attentively after 25 seconds, and with Image B, the attentive observation at right and left took place alternatively after 35 seconds. In other words, regardless of the characteristics of shop displays, the left shops were observed first while in case of the observation after the early and middle time-frame the characteristics of shops were found to have effects on observation. Second, the normal observation showed some difference among attention sections over time while on the whole both images of A and B had the same highly attentive observation at the middle space. Accordingly, it could be concluded that the middle space was playing a faithful role as background for commercial spaces. Third, the ignorant observation, which is the opposite to the attentive observation, was found different between the images of A and B. When the ignorant observation is considered to have intentionality, it will be possible to set up the display which may attract the attention aggressively by the process of figuring out the characteristics of ignored shops.

• KSBB Journal
• /
• v.25 no.2
• /
• pp.187-192
• /
• 2010

We designed the optimal operational strategy in repeated fed-batch ethanol fermentation using Sacchromyces cerevisiae ATCC 24858 in views of ethanol yield, specific ethanol production rate, and ethanol productivity, when the aeration rate were controlled at 0.0 and 0.33 vvm. Coincidentally, the time intervals of withdrawal-fill of culture medium (24 and 36 h) were investigated. Ethanol yield and ethanol productivity when the aeration was carried out at 0.33 vvm were superior to those when the aeration was not carried out. Additionally, those parameters when the time interval of withdrawal-fill of culture medium was 24 h were superior to those when time interval of withdrawal-fill of culture medium was 36 h. The total ethanol production reached at the greatest value, 703.8 g-ethanol, when the aeration was carried out at 0.33 vvm and the time interval of withdrawal-fill of culture medium was 24 h. In this study, we verified experimentally the necessity of designing the operational strategy for increasing ethanol production in terms of aeration rate and time interval of withdrawal-fill of culture medium in the repeated fed-batch ethanol fermentation.

• Journal of Soil and Groundwater Environment
• /
• v.20 no.3
• /
• pp.74-82
• /
• 2015

A method to filter out the effect of river stage fluctuations on groundwater level was designed using an artificial neural network-based time series model of groundwater level prediction. The designed method was applied to daily groundwater level data near the Gangjeong-Koryeong Barrage in the Nakdong river. Direct prediction time series models were successfully developed for both cases of before and after the barrage construction using past measurement data of rainfall, river stage, and groundwater level as inputs. The correlation coefficient values between observed and predicted data were over 0.97. Using the time series models the effect of river stage on groundwater level data was filtered out by setting a constant value for river stage inputs. The filtered data were applied to the hybrid water table fluctuation method in order to estimate the groundwater recharge. The calculated ratios of groundwater recharge to precipitation before and after the barrage construction were 11.0% and 4.3%, respectively. It is expected that the proposed method can be a useful tool for groundwater level prediction and recharge estimation in the riverside area.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.31 no.3
• /
• pp.74-82
• /
• 2003

Under the assumption that the temperature of one location is closely related to land use characteristics around that location, this study is carried out to assess the impact of urban land use patterns on air temperature. In order to investigate the relationship, GIS techniques and statistical analyses are utilized, after spatially connecting urban land use data in Seoul Metropolitan Area with atmospheric data observed at Automatic Weather Stations (AWS). The research method is as follows: (1) To find out important land use factors on temperature, simple linear regressions for a specific time period (pilot study) are conducted with urban land use characteristics, (2) To make a final model, multiple regressions are carried out with those factors and, (3) To verify that the final model could be appled to explain temperature variations beyond the period, the model is extensively used for 5 different time periods: 1999 as a whole; summer in 1999; 1998 as a whole; summer in 1998; August in 1998. The results of simple linear regression models in the pilot study show that transportation facilities and open space area are very influential on urban air temperature variations, which explain 66 and 61 percent of the variations, respectively. However, the other land use variables (residential, commercial, and mixed land use) are found to have weak or insignificant relationship to the air temperatures. Multiple linear regression with the two important variables in the pilot study is estimated, which shows that the model explains 75 percent of the variability in air temperatures with correct signs of regression coefficients. Thus, it is empirically shown that an increase in open space and a decrease in transportation facilities area can leads to the decrease in air temperature. After the final model is extensively applied to the 5 different time periods, the estimated models explain 68 ∼ 75 percent of the variations in the temperatures is significant regression coefficients for all explanatory variables. This result provides a possibility that one air temperature model for a specific time period could be a good model for other time periods near to the period. The important implications of this result to lessen high air temperature we: (1) to expand and to conserve open space and (2) to control transportation-related factors such as transportation facilities area, road pavement and traffic congestion.