• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.2012-2021
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• 1995

An experimental study was performed for the analysis of dynamic characteristics of refrigeration system by controlling the evaporator superheat. Experimental data have been taken utilizing two different devices, thermostatic expansion valve(T.E.V.) and electronic expansion valve(E.E.V.), for the control of the evaporator superheat. The ranges of parameters, such as superheat, mass flow rate of refrigerant and inlet temperature of evaporator were 5-30.deg. C 90-170 kg/h and 10-25.deg. C, respectively. The data taken from the T.E.v.and E.E.v.were discussed with the control of the superheat, pressure drop, refrigerating capacity, compression work, evaporating temperature, condensing temperature and COP affecting performance characteristics of refrigeration system. In case of the refrigerant flow control with T.E..V., the superheat and pressure drop of the evaporator varied periodically, but the control with E.E.V., the parameters were very stable. In E.E.v.control, refrigerating capacity, compression work and evaporating temperature were decreased with increasing superheat, and the highest COP was obtained in the range of superheat from 5.deg. C to 15.deg. C.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.4
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• pp.380-387
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• 1994

An experimental study was performed to investigate the characteristics of refrigerant flow rate control and superheat in an evaporator with an electronic expansion valve(EEV). The EEV used in this study was devised using a needle valve coupled with a stepping motor controlled by a personal computer. A Pill control equation was used to control the superheat of the evaporator and to set the superheat to $5^{\circ}C$. In order to determine an optimum running condition for the system, Pill parameters were varied for the wide range of values. The running condition of an air conditioning system with a PI control was reasonably stable compared with that of the Pill control. Experimental results for the PI control using parameter values, $K_p=1.5$, $T_i=400(sec)$ and $T_s=6(sec)$ show that the superheat reached its target value. When external disturbances were introduced to the system, the superheat target value was reached within about 3 minutes. When the EEV was applied to the air conditioning system driven by an inverter, room temperature control was excellent.

• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.405-408
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• 1988

The origin of Jindo dogs has been controversial. It has been informed by words of mouth that they are the offsprings of either the digs of Sung dynasty (960~1279 A.D.) in China or the Mongolian dogs. Some breeds of dogs in Japan now have almost same appearance as Jindo dogs. The authors reviewed the history of Japan and found that Korean hunting dogs were sent to Japan in early 5th century, which was before Sung dynasty of China. Dr. Jae-Keun Ryu of National Institute of Environmental Research has done some work on serums of dogs of both Korea and Japan; the results of his serological and molecular biological studies indicated that Korean dogs were sent to Japan 1,300~2,500 years ago. Jindo dogs appear to be the descendants of the dogs of the Stone Age. They have adapted themselves to the unfavorable environment of Jindo island so that they can maintain pure line-age and wild nature until today. It was concluded that they are Korean native dogs, not the offsprings of the dogs of Sung dynasty or the Mongolian dogs.

• KOMUNHWA
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• no.56
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• pp.3-27
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• 2000

Hunting and gathering was the primary way to live in the Korean peninsula during the neolithic age. People were not able to invest much labor in making their tombs because of so much activity for their living. Small tombs like the shallow pit tomb(土壙墓) we

• Journal of Families and Better Life
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• v.3 no.1
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• pp.15-22
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• 1985

This study was designed to examine leisure time and leisure activities of homemakers and to predict future leisure time and future leisure time orientation. Present leisure time and future leisure time orientation were studied in relation to sociodemographic and physical environmental variables, time use variables and attitude variables. The major findings were the average daily housework time of homemakers was 6.5 hours on weekends. Housework time of employed homemakers was 3.5 hours and full-time homemakers was 8.0 hours. Daily leisure time of homemakers was 4.0 hours on weekdays and 4.8 hours o weekends. Most homemakers leisure activities on weekdays and weekends were reading, watching TV or listening to the radio and resting. In the future, they want to go hiking, hunting, traveling or fishing, attending concerts, drama or movies and playing sports games. The homemakers who felt their amount of present leisure time was sufficient were 35.4% and insufficient were 37.9%. Regarding the present leisure activities, 43.1% of homemakers expressed dissatisfaction, though 21.9% of them satisfied. Factors affecting the homemakers weekday leisure time were homemakers' occupation, family type, type of heating form house and cooking, weekday and weekend housework time of homemakers. Weekend leisure time interacted with family life cycle, number of children, income, education and occupation of homemakers, size of house, type of heating for house and cooking, weekday housework time of homemakers. housework time of employed housekeeper, husbands' weekend housework time, weekday leisure time of homemakers.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.69-70
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• 2008

Automatic control systems(AVR, Governor, Synchronizer) installed $1970{\sim}1980$ in K-water were considered to be rehabilitated around 2000. Moreover, Korea Power Exchange market system was changed from PPA (Power Purchase Agreement) to a bidding system. Therefore, depending on the power quality, the power provider could achieve additional profits. It is the excitation system and governor that have the functions of enhancing power necessities. During the 20 to 30 years of generator operation, there were many major and minor problems. Examples are SCR burnout (Andong: Excitation system), hunting (Imha: governor), field circuit breaker failure (Chungju 1st: excitation system), the rise of leakage current (Chungju 2nd: excitation system), power supply burnout (Chungju 2nd: governor). These are the typical examples of malfunction which hindered the generator operation and, consequently, diminished the profit of power business. In order to satisfy the needs of the power market and prevent malfunctions mentioned above, the rehabilitation of AVRs and governors were executed. A new system was made to have the flexibility of ancillary service (GF, AGC, etc.), PSS function. With user friendly HMI software, it is more convenient for the operator to fulfill suitable maintenance. It was possible to connect SCADA system by opening protocol of AVR, governor for the efficiency of operation and maintenance.

• Steel and Composite Structures
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• v.37 no.1
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• pp.1-14
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• 2020

Composite beams with corrugated steel webs represent a new innovative system which has emerged in the past decade for medium span in the construction technology. The use of composite beams with corrugated steel webs results in a range of benefits, including flexible spaces and reduced foundation costs in the construction technology. The thin corrugated web affords a significant weight reduction of these beams, compared with hot-rolled or welded ones. In the current research, an optimal designed I-girder beam with corrugated web has been proposed to improve the structural performance of continuous composite girder under bending moment. The experimental program has been conducted for six simply supported composite beams with different loading conditions. The tested specimens are designed by using one of the stochastic techniques called hunting search algorithm. In the optimization process, besides the thickness of concrete slab and studs, corrugated web properties are considered as design variables. The design constraints are respectively implemented from Eurocode 3, BS-8110 and DIN 18-800 Teil-1. The last part of the study focuses on performing a numerical study on composite beams by utilizing finite element analysis and the bending behavior of steel girders with corrugated webs experimentally and numerically verified the results. A nonlinear analysis was carried out using the finite element software ANSYS on the composite beams which were modelled using the elements ten-node high order quadrilateral type.

• BMB Reports
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• v.50 no.1
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• pp.3-4
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• 2017

Recent advances in genome sequencing technologies have enabled humans to generate and investigate the genomes of wild species. This includes the big cat family, such as tigers, lions, and leopards. Adding the first high quality leopard genome, we have performed an in-depth comparative analysis to identify the genomic signatures in the evolution of felid to become the top predators on land. Our study focused on how the carnivore genomes, as compared to the omnivore or herbivore genomes, shared evolutionary adaptations in genes associated with nutrient metabolism, muscle strength, agility, and other traits responsible for hunting and meat digestion. We found genetic evidence that genomes represent what animals eat through modifying genes. Highly conserved genetically relevant regions were discovered in genomes at the family level. Also, the Felidae family genomes exhibited low levels of genetic diversity associated with decreased population sizes, presumably because of their strict diet, suggesting their vulnerability and critical conservation status. Our findings can be used for human health enhancement, since we share the same genes as cats with some variation. This is an example how wildlife genomes can be a critical resource for human evolution, providing key genetic marker information for disease treatment.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.119-129
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• 1999

It may be said that ancient wild Chinese garden had been founded during Qin dynasty and completed through Han, Sui and Tang dynasties. At first used as hunting areas for kings, the ancient resort forests began to take forms of garden. They dug a pond in the garden and made a simulated mountains with the soil that came from the excavations for the pond and suc pavilions has Gyong, Ru, Gak etc. were built around the pond. The ponds were different in size from those in Korea, being of the lake-like size. they made three island in the pond, which were the islands of Taoist hermits with supernatural powers, called Bong-lae, Young-ju and Band-jang respectively. the traditional of making those islands began in the Qin era and were completed in the Han era, being descended to posterity as a traditional garden structure of 'three islands in one pond' garden style. Such style was brought to Korea and first appeared as Kung-Nam-Ji in Back-jae kingdom and then brought to Japan, becoming the tradition of constructing ponds from early Heian era. Those lake-like huge Chinese ponds constituted the core of ancient garden where various feasts took place. Such ponds were also placed at the center of the gardens and played the roles of feasting garden ponds. Through the above-mentioned studies of the ancient Chines garden, the origin of them and the influence of the ancient Chinese ponded garden upon those of Korea and Japan were investigated.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.2
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• pp.187-192
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• 2004

In this paper, we proposed the method to design fuzzy controller using the experience of the operating expert and experimental numeric data for the robust control about the noise and disturbance instead of the traditional PID controller for the main steam temperature control of the thermal power plant. The temperature of main steam temperature process has to be controlled uniformly for the stable electric power output. The process has the problem of the hunting for the cases of various disturbances. In that case, the manual action of the operator happened to be introduced in some cases. We adopted the TSK (Takagi-Sugeno-Kang) model as the fuzzy controller and designed the fuzzy rules using the informations extracted directly from the real plant and various operating condition to solve the above problems and to apply practically. We implemented the real fuzzy controller as the Function Block module in the DCS(Distributed Control System) and evaluated the feasibility through the experimental results of the simulation.