• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.306-309
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• 1993

Digital redesign techniques are to derive a digital controller fred the existing continuous controller and its plant so that the performance of the digitally controlled system is matched as closely as possible to that of the original continuous system at the sampling instants. Recently a new digital redesign technique, was developed to use the generalized sampled-data hold function(GSHF) based on the the grammian matrix. With this new technique the digitally redesigned system showed several good features compared with any existing technique in terms of the state match at the sampling instants, the large sampling period, and the transient reponses. This paper concerns a further improvement of the new digital redesign technique by employing the discrete grammian matrix instead of the continuous grammian matrix in defining GSHF. With this modification, it was observed by simulation that the transient response of the modified digital system shows far better performance than the digital system based on the continuous grammian matrix.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.95-101
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• 2006

The purpose of this study is to present the simulation results and an overview of the performance assessment of the Ground-Source Heat Pump(GSHF) system. The calculation was performed for two design factors: the spacing between boreholes and the depth of the vertical ground heat exchangers. And the simulation was carried out using the thermal simulation code TRNSYS with new model of water to water heat pump developed by this study. As a result, it was anticipated that the yearly mean COPs of heat pump for heating and cooling are about 3.7 and 5.8 respectively and the heat pump can supply 100% of heating and cooling load all the year around.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.3
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• pp.240-246
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• 2002

Bypass air conditioning systems are divided into three types; an outdoor air bypass, a mixed air bypass and a return air bypass system. What makes the return air by pass system more effective is that it directs all of moist outdoor air through the cooling coil. The bypass air conditioning system can maintain indoor R.H (Relative Humidity) less than a conventional CAV (Constant Air Volume) air conditioning system by adjusting face and bypass dampers at part load. When a design sensible load (the ratio of sensible load to total sensible load) is 70 percent (at this time, RSHF (Room Sensible Heat Factor) . 0.7), indoor R.H was maintained 59 percent by the return air bypass system, but 65 percent by the conventional CAV air conditioning system (valve control system). The bypass air conditioning system can also improve IAQ (Indoor Air Quality) in many buildings where the number of air change is high.

• Journal of Nutrition and Health
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• v.38 no.1
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• pp.3-10
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• 2005

The study analyzed the lipid patterns and fatty acid compositions of serum and liver tissues in groups of Sparague-Dawley rats. Some of the groups were fed with an basal diet, which contained com oil (C), grape seed oil (GSO), or perilla oil (P), and the others were fed with a high fat diet, which had cholesterol (1%) and lard (10%) mixed with corn oil (CHF), grape seed oil (GSHF), or perilla oil (PHF). The amount of dietary intake was higher for the basal diet groups than the high fat diet groups. And diet efficiency was significantly low in the group of rats fed with the basal diet mixed with perilla oil. From the analysis of the serum lipid patterns, a significant decrease in total lipid concentration was observed in the group of rats fed on the basal diet mixed with perilla oil and the high fat diet group. The levels of triglyceride and phospholipid were significantly low in the basal diet group when perilla oil or grape seed oil was involved. The ordinary diet groups showed significantly higher in HDL-C than the high fat diet groups. There was no significant difference among the basal diet groups, whether the diet was mixed with grape seed oil, perilla oil, or com oil. However, a significant increase in HDL-C was observed in the group of rats fed with the high fat diet containing perilla oil. For LDL-C, there was a significant difference between the high fat diet groups and the basal diet groups. LDL-C was especially low in the group of rats fed with the high fat diet to which perilla oil was added, and the grape seed-added high fat diet group showed a decreasing tendency in LDL-C. The content of total fat, total cholesterol, and triglyceride was the lowest in the group of rats fed with the perilla oil-containing basal diet, and this group was followed in order by the grape seed oil-containing diet group and com oil-containing diet group. In the analysis of the fatty-acid composition in liver tissue, the high fat diet groups showed an increase in saturated fatty acids and polyunsaturated fatty acids, but a decrease in mono unsaturated fatty acids when compared to the basal diet groups. The composition ratio of fatty acids varied according to which type of oil the diet contains. Our finding suggest that grape seed oil was an apparent diet effect on the fatty-acid composition.