• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.2
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• pp.94-101
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• 1993

Recently, efforts of decreasing energy consumption are continously increased and user's preference is also diversified in refrigeration and air conditioning systems. Thus, in order to satisfy these demands, high efficiency, high intelligence, and energy saving for those systems are essential. As the basic study for diverse functions and intelligence of those systems, we investigated the response characteristics through the compressor capacity control concerned with superheat and refrigeration room temperature. And, response characteristics are investigated experimentally by using micro computer based PWM inverter control method. Experimental result of the conventional on-off control method is given in order to be compared to the results of inverter control method. The results obtained through this study are summarized as follows. It is shown from the experimental results of the on-off control method that the range of temperature variation around the steady state ($-18^{\circ}C$) is very large (about $7{\sim}8^{\circ}C$) and the settling time bringing the steady state is not found. In the inverter control method, we can see that the refrigeration room temperature after reaching the setting temperature is very stable without fluctuation and a robust control for disturbance such as opening the door has been realized.

• Journal of the Korean Dietetic Association
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• v.6 no.2
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• pp.79-85
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• 2000

This study was undertaken to investigate the physicochemical characteristics and intake rate of Kimchi provide to five foodservice elementary schools in Sungnam area selecting 4th and 6th grade students pH indicated 4.73-5.29 at before-serving state. Total acidity were 0.23-0.44% and salinity just before-serving state were 2.41-2.82%. Vitamin C were 6.88-8.12mg% and Total dietary fiber showed the range of 19.18-22.60. While the intake rate of kimchi of female students was higher than that of male students for 4th grade students, the intake rate of kimchi of male students was higher than that of female students for 6th grade students. As a whole, the intake rate of male students was higher than that of female students. The intake rate of male students correlated significantly that of female students, the preference rate of kimchi was almost the same regardless of sex distinction.

• Journal of the Korean Home Economics Association
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• v.32 no.5
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• pp.135-142
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• 1994

This research was undertaken to investigate the state of lunchbox preperation and the opinion of operating school lunch program. The subjects were 180 mothers and their children in the 6th grade of elementary school in Seoul, where a school lunch program were not operated. The results were summarized as follows ; The age of mothers were from 30's to 40's and among them over 80% graduated from a high school and 26.1% had a job. 88.9% of mothers prepared lunchbox everytime and main dish was mostly bab. The average time spent in preparing meal for one day and lunchbox were 1 hour and 58 minutes, and 28.6 minutes respectively. The number of side dishes cooked per day and for lunchbox were 9 and 3, respectively. The side dishes for lunchbox were kimchi, dried layer, ham, dried squid, egg in decreased order, which were similar to preference of children. Animal protein foods were mainly used in lunchbox than vegetables. On preparing lunchbox, mothers considered preferance, nutrition, convenience of cook, economic, appearance of food in decreased order. 92% of mothers and 75% of their children approved of operating school lunch program, and the reason, answered by their mothers, was nutritional balance of their children. In conclusion, it's needed to operate of school lunch program for optimal nutritional intake and growth of children.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.210-219
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• 2010

Consumers differ in both horizontally and vertically. Market segmentation aims to divide horizontally different (or heterogeneous) consumers into more similar (or homogeneous) small segments. A specific consumer, however, may differ in vertically. He (or she) may belong to a different market segment from another one where he (or she) belonged to before. In consumer panel data, the vertical difference can be observed by his (or her) choice among brand alternatives are changing over time. The consumer's vertical difference has been defined as 'dynamics'. In this research, we have developed a binary probit model with random-walk coefficients to capture the consumer's dynamics. With an application to a consumer panel data, we have examined how have the random-walk coefficients changed over time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.246-256
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• 1999

This study was undertaken to investigate the perception and the consumption behavior for the meats in Koreans. The subjects were 491 Koreans including the ones residing in New Zealand. Most of subjects answered the meats are used for supper time. The frequency of the meats intake was affected by education and monthly income level. 69.2% of the subjects had positive response such as increased stamina and fulled stomach for psychological state after the meats intake. The use of meats recently revealed that 48% of the subjects have decreased its consumption. The main reasons diminished the use of meats were for the good health and economic state. Women were found to avoid the meats fat to a greater degree than men. The kinds of the meat used frequently were beef, pork and chicken. The younger tended to higher the frequency of the processed meats intake than the older. According to 3 level of BMI of the subjects, there were significant differences in the amount of the meat intake and perception for necessity of the meat. This study showed that the higher the preference for meat, the education and the monthly income level, the more the meat intake frequency. There were not significant differences between Koreans residing in domestic and New Zealand except the dog meat in the perception and consumption of the meat.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2805-2826
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• 2021

In most cases, the routing policy of networks shows a preference for a static one-to-one mapping of communication pairs to routing paths, which offers adversaries a great advantage to conduct thorough reconnaissance and organize an effective attack in a stress-free manner. With the evolution of network intelligence, some flexible and adaptive routing policies have already proposed to intensify the network defender to turn the situation. Routing mutation is an effective strategy that can invalidate the unvarying nature of routing information that attackers have collected from exploiting the static configuration of the network. However, three constraints execute press on routing mutation deployment in practical: insufficient route mutation space, expensive control costs, and incompatibility. To enhance the availability of route mutation, we propose an OpenFlow-based route mutation technique called Polymorphic Path Transferring (PPT), which adopts a physical and virtual path segment mixed construction technique to enlarge the routing path space for elevating the security of communication. Based on the Markov Decision Process, with considering flows distribution in the network, the PPT adopts an evolution routing path scheduling algorithm with a segment path update strategy, which relieves the press on the overhead of control and incompatibility. Our analysis demonstrates that PPT can secure data delivery in the worst network environment while countering sophisticated attacks in an evasion-free manner (e.g., advanced persistent threat). Case study and experiment results show its effectiveness in proactively defending against targeted attacks and its advantage compared with previous route mutation methods.

• Asia Marketing Journal
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• v.18 no.4
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• pp.125-138
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• 2017

The goal of the study is to understand how consumers' constraint as opposed to utility structure gives rise to final decision when consumers purchase more than one variant of product at a time, i.e., horizontal variety seeking or multiple-discreteness. Purchase and consumption decision not only produces utility but also involves some sort of cognitive pressure. Past consumption or last purchase is likely to be linked to this burden we face such as concern for obesity, risk of harm, and guilt for mischief. In this research, the existence and the role of dynamic constraint are investigated through a microeconomic utility model with multiple dynamic constraint. The model is applied to the salty snacks data collected from field study where burden for spiciness serves as a constraint. The results are compared to the conventional multiple discreteness choice models of static constraints, and policy implications on price discounts is explored. The major findings are that first, one would underestimate the level of consumer preference for product offerings when ignoring the carry-over of the concern from the past consumption, and second, the impact of price promotion on demand would be properly evaluated when the model allows for the role of constraint as both multiple and dynamic. The current study is different from the existing studies in two ways. First, it captures the effect of 'mental constraint' on demand in formal economic model. Second, unlike the state dependence well documented in the literature, the study proposes the notion of state dependence in different way, via constraint rather than utility.

• The Journal of Economics, Marketing and Management
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• v.3 no.4
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• pp.5-11
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• 2015

The study examined the socio-economic factors influencing the participation of rural farming households in barter trade in Ondo State, Nigeria. The objectives were to compare the socio-economic characteristics of the participants and non-participants in barter trade, analyze the preference for barter trade and identify the constraints to it. Also, the factors affecting respondents' participation in barter trade were identified. Empirical results indicated that there were significant differences in the socio-economic characteristics of the participants and non-participants in barter trade. The SWOT analysis showed that possession of agrarian attributes by the locality where the trade is practiced was the strongest factor ensuring the survival of barter in the study area. Double coincidence of wants was found to be the most prevailing weakness associated with barter while the major reason for participation by some households was that the quantity of commodities received is usually higher compared with cash transactions. Transportation cost to barter markets was found to be the greatest threat to the continued existence of barter trade in the area. The results of the Probit model showed that age, household size, transportation cost to cash markets, farm size, distance to barter markets, and formal education significantly affected the probability participating in barter trade.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.83-91
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• 2006

As a demand for sustainable development rises, the preference for earth house (earth construction) increases gradually. However, there are few data for predicting and evaluating the thermal environment and indoor air quality of earth house. Thus, this study aims to measure thermal properties(thermal conductivity, density and specific heat) and pollutants emission intensities(formaldehyde and volatile organic compounds) of current main earth construction materials and make a comparison between earth and cement construction materials. As results, quantitative thermal properties and pollutants emission intensities of current main earth construction materials are shown.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.294-297
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• 2004

Mean squared error (MSE) is an effective criterion to combine the mean and the standard deviation responses in dual response surface optimization. The bias and variance components of MSE need to be weighted properly in the given problem situation. This paper proposes a systematic method to determine the relative weights of bias and variance in accordance with a decision maker's prior and posterior preference structure.