• Journal of KIISE:Software and Applications
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• v.41 no.7
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• pp.481-491
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• 2014

The power production using renewable energy is more important because of a limited amount of fossil fuel and the problem of global warming. A concentrative photovoltaic system comes into the spotlight with high energy production, since the rate of power production using solar energy is proliferated. These systems, however, need to sophisticated tracking methods to give the high power production. In this paper, we propose a hierarchical tracking system using modular Bayesian networks and a naive Bayes classifier. The Bayesian networks can respond flexibly in uncertain situations and can be designed by domain knowledge even when the data are not enough. Bayesian network modules infer the weather states which are classified into nine classes. Then, naive Bayes classifier selects the most effective method considering inferred weather states and the system makes a decision using the rules. We collected real weather data for the experiments and the average accuracy of the proposed method is 93.9%. In addition, comparing the photovoltaic efficiency with the pinhole camera system results in improved performance of about 16.58%.

• Journal of Distribution Research
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• v.6 no.2
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• pp.19-40
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• 2002

According to the secondary data, private brand(PB)'s share of retail sales is 25-30% in the USA, but about 45 in Korea. In Korea PB's average price is 23.3% less than manufacturer brand. It is very interest that PB's price advantage doesn't have a good effect on it's share of retail sales. This research's objective is to study why Korean consumers don't purchase private brand cheaper than manufacturer brand. A theoretical reasoning depends on information cue theory and means-ends model of perceived value. A unit of analysis is consumers who purchase private brand at E-mart in Pusan city, one of largest discount store in Korea. Hypothesis tested by Lisrel's structural equation model and interesting results as follows: First, favorable brand image among extrinsic cues is most positively correlated with perceived quality/sacrifice and intrinsic cues is also statistically significant. This fact imply that intrinsic cues; package, logo, country of origin are very important in the adoption of private brand in Korea. Second, compared with manufacturer's brand, PB's perceived price is positively correlated with perceived quality/sacrifice. This fact imply a assimilation effect between manufacturer's brand and private brand. Finally, a correlation between perceived sacrifice and PB proneness is satistically insignificant, but perceived quality has a significant effect on its proneness. this fact imply that innovators(about 4% of potential consumer) are risk-taker.

• Journal of Astronomy and Space Sciences
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• v.19 no.1
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• pp.67-74
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• 2002

Optical observations of Geostationary and Molynia orbit spin-stabilized satellites over the Korean peninsula have been carried out at the Kyung Hee University Observatory with a 30 inch telescope. We have observed 5 spin-stabilized satellites, and obtained 0spin periods, which can be used for deducing a design for each bus model. Verifications of spin periods of 3 known satellites from manufacturer, and observations of 2 unknown satellites were made. The difference between known spin periods and observed spin periods is 0.06sec on the average and the difference of those spin rates is 3.3rpm on the average. Those results indicate that spin periods and spin rates of observed geostationary spin-stabilized satellites are within operating limits. Spin rates of unknown satellites, Fengyun 2B and Molynia 1-87 are 89.3rpm, 78.4rpm earh. It is suggested that the research of spin stabilized satellites can be used for the determinations of standard light sources for short period celestial objects and helpful for the constructions of satellite databases with photometric and/or spectroscopic satellite observations.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.475-484
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• 2000

The purpose of this study was to develop model for estimating biodegrability of organic sludge (sewage and papermill) in various environmental conditions. to assume degradable degree with operating time of SRB reactor. and evaluate duratior of organic sludge as carbon source. Average TCOD was 28.7~63.2mg/L in effluent. organic sludge did not much supply carbon source for experimental period. But in point of durability. it seemed that organic sludge was efficient because it was not consumed by degradation of much organic matter within short period. With increasing $SO_4{^{2-}}$ reduction rate. Pb and Fe was removed 77~82% and 33~59%. respectively. Because Al was precipitated as a hydroxide. its removal rate wa,. about $54{\pm}2%$ in R-l~R-3 maintaining low pH but about 78% in R-4 maintaining high pH. Because Mn was large in solubility. it showed to be much lower than other heavy metals. Considering supportable capacity or durability of orgainc matter for initial SRB mixing ratio of sewage/papermill 0.5 was regarded as appropriate substituting material and at this time. it estimated that carbon source continued about 3.08 year but safety factor must apply to be thought over. because various factors had an effect on degradation of organic sludge.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.827-834
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• 2013

The water footprint of product and service is the total volume of freshwater consumed, directly and indirectly, in the life cycle of a product and service. Up to date, water consumption data for industries and products were not well quantified and developed. Especially it is important to construct for agriculture industry which consumes lots of water. In this study, by using Cropwat 8.0 model, we tried to evaluate regionalized water consumption related with rice production in agriculture industry in eight regions (Gangwon, Gyeongi, Gyeongbuk, Gyeongnam, Jeonnam, Jeonbuk, Chungnam, Chungbuk). As a result, Gyeongbuk region has the lowest water consumption in rice production, which is $1,356.68m^3/ton$, on the other hand, Jeonnam region has the highest water consumption ($1,669.54m^3/ton$). By using the average indirect water consumption ($1,487.87m^3/ton$) of eight regions and direct water consumption, the total water footprint for the rice amount of rice bowl size (130 g), which is 193.6 L was calculated. Based on this research approach, we should develop water footprint database of all agriculture products and expand to other industrial sectors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6602-6609
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• 2013

This study is expected to provide background data for establishing mitigation measures for malodor and for comparing complex odor criteria. The impact of malodor at the afflicted locations was analyzed using Industrial Source Complex Short Term 3 (ISCST3) model, which was recommended by the EPA. The Odor Emission Rates (ODR) for piglets and hogs were predicted based on the average, minimum, and maximum emission rates as classification. The forecasting result of the complex odor modelling of pigsty showed that tolerance limit was exceeded at an adjacent administration building, but tolerance limit was not surpassed at an afflicted location which was within 185m from the pigsty. The ISCST3 modelling of the satisfactory ODR for tolerance limit was accomplished at the administration building. From the prediction of this modelling, maximum emission rates based on 1hr at administration building were 10.59~52.93, 19.05~31.76, and 10.59 $OU/m^3/s/m^2$ at emission rates of 50%, 30%, and 10%. This emission rate was slightly higher than the tolerance limit of 10.00 $OU/m^3/s/m^2$. However, it was inferred that the tolerance limit could be satisfied if the emission rate of 10% was controlled.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2020-2028
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• 2015

This study was conducted in order to identify factors influencing maternal-fetal attachment among pregnant women, considering the factors presented in Mercer's theory: Becoming a Mother(pregnancy stress, self-esteem, dyadic adjustment, sense of mastery, antepartum stress). The data was collected through structured questionnaires from 140 pregnant women who visited the obstetric clinic and public health centers in a metropolitan area to have prenatal tests from August 23th to November 25th 2014. The data were analyzed by SPSS 20 software using descriptive statistics, the t-test, ANOVA, the Pearson's correlation coefficients and a stepwise multiple regression. The results were as follows: Maternal-fetal attachment in the group of pregnant women under 30 years of age was significantly higher than that in the group of over the age of 31(t=2.79,p=.004). Primiparas had higher maternal-fetal attachment than multiparas(F=3.27, p=.041). There was a negative correlation between pregnancy stress(r=-0.22, p=.009) and maternal-fetal attachment. Self-esteem (r=0.45, p<.001), dyadic adjustment(r=0.42, p<.001), sense of mastery(r=0.24, p=.005) and maternal-fetal attachment were, however, positively correlated. It was found that self-esteem, dyadic adjustment and age were some of the factors influencing maternal-fetal attachment among pregnant women. These variables explained 26.1% of the variance in maternal-fetal attachment. Findings of this study indicate needs for comprehension and assessment of self-esteem and dyadic adjustment in pregnant women through prenatal tests. Also, the intervention programs to improve maternal-fetal attachment among older mothers should be developed and implemented.

• Journal of KIISE:Software and Applications
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• v.30 no.7_8
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• pp.672-680
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• 2003

A shopbot is a software agent whose goal is to maximize buyer´s satisfaction through automatically gathering the price and quality information of goods as well as the services from on-line sellers. In the response to shopbots´ activities, sellers on the Internet need the agents called pricebots that can help them maximize their own profits. In this paper we adopts Q-learning, one of the model-free reinforcement learning methods as a price-setting algorithm of pricebots. A Q-learned agent increases profitability and eliminates the cyclic price wars when compared with the agents using the myoptimal (myopically optimal) pricing strategy Q-teaming needs to select a sequence of state-action fairs for the convergence of Q-teaming. When the uniform random method in selecting state-action pairs is used, the number of accesses to the Q-tables to obtain the optimal Q-values is quite large. Therefore, it is not appropriate for universal on-line learning in a real world environment. This phenomenon occurs because the uniform random selection reflects the uncertainty of exploitation for the optimal policy. In this paper, we propose a Mixed Nonstationary Policy (MNP), which consists of both the auxiliary Markov process and the original Markov process. MNP tries to keep balance of exploration and exploitation in reinforcement learning. Our experiment results show that the Q-learning agent using MNP converges to the optimal Q-values about 2.6 time faster than the uniform random selection on the average.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.26-35
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• 2006

In this paper, an automatic mobile robot system for a intelligent path planning using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth information can be detected. Finally, based-on the analysis of these calculated coordinates, a mobile robot system is derived as a intelligent path planning and a estimation. From some experiments on robot driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the distance between the mobile robot and the objects, and relative distance between the other objects is found to be very low value of $2.19\%$ and $1.52\%$ on average, respectably.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.227-238
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• 2006

Line density index(LDI) was developed to quantify a densely isothermal line rate as standard index in the ocean environment. Theoretical background on the LDI development process restricting index range 0 to 100 was described. And validation test was done for the LDI application condition that total line length is not greater than 1/10 of unit area. NOAA SST(Sea Surface Temperature) data were used for the experimental application of LDI in the South Sea of Korea. Using GIS, $0.1^{\circ}C$ isothermal lines were linearized as vector data form SST raster data, and unit area were built as polygon data. For the LDI calculation, spatial overlapping(line in polygon) was implemented. To analyze the effect of unit area size for the LDI distribution, two cases of unit area size were designed and descriptive statistics was calculated including performing normality test. The results showed no change of LDI's essential characteristics such as mean and normality except for the range of value, variance and standard deviation. Accordingly, it was found that complex structure of thermal front and even smaller scale of front width than unit area size could influence on the LDI distribution. Also, correlation analysis performed between LDI and difference of temperature(${\Delta}T^{\circ}C$), and horizontal thermal gradient(${\Delta}T^{\circ}C/km$) on the front was obtained from linear regression model. This obtained value was compared with the results from previous researches. Newly developed LDI can be used to compare the thermal front regions changing spatio-temporally in the ocean environment using absolute index value. It is considered to be significant to analyze the relationship between thermal front and marine environment or front and marine organisms in a quantitative approach described in this study.