• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.85-92
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• 2005

Due to the friction characteristic of pump, cylinder, and between passenger car and the rail, there exist dead zone in the hydraulic system actuated with inverter, which can not be controlled by a PID controller. In this paper, the friction characteristic of a cylinder is considered first, which may cause the uncontrolled speed in the zero-crossing speed region. And then, the zooming fuzzy logic controller is designed to overcome the drawback by the existing PID speed controller. Finally, The proposed hybrid fuzzy controller is applied to the PID controller in the normal speed region and to the fuzzy controller in the zero-crossing speed region. The reason is that the problem of the uncontrolled speed in the zero-crossing speed region caused by the friction characteristic of the cylinder in hydraulic elevator can be solved, and the effectiveness of the controlling system not only in the zero-crossing speed region but also the overall controlling region including steady-state can be simulated and performed.

• Korean Journal of Environment and Ecology
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• v.23 no.4
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• pp.302-308
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• 2009

For the proper tree management of Taxus cuspidata, distributed in the High 1 Ski Slope construction area in Baekwoonsan, Jeungsun-gun, Kangwon-do, the growing states of 323 trees(including transplanted 57trees) are investigated. Tree height, rootcollar diameter, D.B.H., stem condition, apical shoot, dead branch, needle growth condition, 2-year-old needle loss, root condition, tree form are investigated. Taxus cuspidata are mainly growing at the sites, high elevated mountain ridge or slopes facing north. Growing states of Taxus cuspidata, distributed in Baekwoonsan are relatively better than those of Taxus cuspidata and Abies koreana at other subalpine zone in Korea. Damaged trees are mainly due to root-removal through transplanting, root-damages by raising the ground level and digging. Several methods of Taxus cuspidata conservation were suggested.

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.55-64
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• 2007

In general mechanical servo systems, friction deteriorates the performance of controllers by its nonlinear characteristics. Especially, friction phenomenon causes steady-state tracking errors and limit cycles in position and velocity control systems, even though gains of controllers are tuned well in linear system model. Even if sensor is used higher accuracy level, it is difficult to improve tracking performance of the position to the same level with a general control method such as PID type. Therefore, many friction models were proposed and compensation methods have been researched actively. In this paper, we consider that the variation of mover's mass is various by loading and unloading. The normal force variation occurs by it and other parameters. Therefore, the proposed control system is composed of main position controller and a friction compensator. A parameter estimator for a nonlinear friction model is designed by adaptive control law and adaptive backstepping control method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.116-127
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• 2013

Korea, like most of other countries, is enforcing the national pension as social insurance which is a kind of the income policy. Despite the fundamental limitation on public pension or the imperfect policy, the guarantee of the minimum living standard for maintaining dignity of human being is not being reached for the standard. Poverty rate of the elderly in Korea is the first among the OECD countries and public pension dead zone is very large. The elderly low income class could become a serious social problem if low fertility and aging keep getting worse. In this study, I will analyze the present condition of the retirement security for the elderly in South Korea. Also, I will look into the present situation of old-age income security and determine problems, and propose the improvement devices for related laws.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1660-1670
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• 2015

Many robust controllers have been studied but most are considered in the theoretical point of view and can be used for only specific systems. So, in this paper, a more practical robust controller is proposed based on SMC(sliding mode control) and disturbance observer. The integral sliding mode is used to eliminate the reaching phase and minimizes the steady-state error, and the disturbance observer reduces the chattering due to the switching input for the bounded disturbances. The inevitable chattering of SMC is also removed by replacing the sign function with dead-zone function. The proposed controller has the improved steady-state error and robustness compared to PID controller.

• Journal of Legislation Research
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• no.41
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• pp.171-200
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• 2011

Protection of vulnerable people in our country today, "the National Basic Livelihood Security Act," is primarily responsible. But current law income and wealth, and by a person responsible for supporting consider only the absolute protection of the poor, and because it is insufficient for the protection of vulnerable people. Specifically, current law does not mean the relative poverty of vulnerable people is limited to the protection of economic demand. It also incorporates the payment of salaries paid individual because the people most vulnerable to social protection is insufficient demand. Dependent regulation is too strict and a person responsible for supporting do not receive legal protection by forming a dead zone is a major cause. In this study, the development direction for the protection of vulnerable people suggests. The first, "National Basic Livelihood Security Act" award in determining the minimum cost of living is relatively proposed to introduce the concept of poverty. Second, payment of the consolidation benefit and the individual benefit to adopt a intermix approach, the social needs of vulnerable people to adapt to that proposed. Third, a person responsible for supporting dependent criteria and whether according to the actual supporting to be judged.

• Journal of Biomedical Engineering Research
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• v.43 no.6
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• pp.390-398
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• 2022

Ultrasound examination using ultrasound equipment is an ultrasound device that images human organs using sound waves and is used in various areas such as diagnosis, follow-up, and treatment of diseases. However, if the quality of ultrasound equipment is not guaranteed, the possibility of misdiagnosis increases, and the diagnosis rate decreases. Accordingly, The Korean Society of Radiology and Korea society of Ultrasound in Medicine presented guidelines for quality management of ultrasound equipment using ATS-539 phantom. The DenseNet201 classification algorithm shows 99.25% accuracy and 5.17% loss in the Dead Zone, 97.52% loss in Axial/Lateral Resolution, 96.98% accuracy and 20.64% loss in Sensitivity, 93.44% accuracy and 22.07% loss in the Gray scale and Dynamic Range. As a result, it is the best and is judged to be an algorithm that can be used for quantitative evaluation. Through this study, it can be seen that if quantitative evaluation using artificial intelligence is conducted in the qualitative evaluation item of ultrasonic equipment, the reliability of ultrasonic equipment can be increased with high accuracy.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.275-280
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• 2022

Suspended solids play an important role in the growth and survival of aquatic organisms. The marine zooplankton species tested in this study were Tigriopus west (Copepoda) and Haustorioides koreanus (Amphipoda) sampled from the intertidal zone, including Artemia nauplii(Branchiopoda) hatched from cysts. The study design included six concentrations (0, 50, 100, 250, 500, and 1,000mg L^-1) of the suspended test particles assayed in triplicate. Experimental cultures in 500 mL-round polycarbonate bottles were subsampled after 96 h to count dead zooplankton. The culture bottles were agitated at 4 RPM on a rotating wheel at 23℃ and 30 PSU. The survival rates of Artemia nauplii and T. west were not affected by suspended solid concentrations higher than 50.0 mg L^-1, whereas the survival rate of H. koreanus decreased with increasing concentrations (p<0.05). In conclusion, H. koreanus and T. west, which were continuously exposed to suspended solid concentrations higher than 50.0 mg L^-1, were affected by low-intensity ecological stress. However, in the case of H. koreanus, a concentration of 50.0 mg L^-1 may be considered to be the limit of tolerance to suspended solids, suggesting that the number of individuals who eventually die will increase if continuously exposed.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.147-153
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• 1975

During 1973 a field experiment was carried out to evaluate effectiveness of the root zone application of insecticides in medical gelatin capsules for control of several rice insect pests and dwarf virus disease. At three days after transplanting the capsules were pushed by hand about 2.5cm into the soil, near roots of Tongil rice plants. At the given day intervals number of leaf-and plant-hoppers on the hills were recorded by direct count, and dead hearts and white heads by stem borers and dwarf virus infected hills were observed in the experiment plots. Finally grain yields were measured. The percentages of dead hearts and white heads in all the plots were too low for evaluating the effectiveness of insecticides against the striped rice borers. Carbofuran of the insecticides tested was relatively effective against green rice leafhopper (Nephotettixcincticeps) and small brown planthopper (Laodelphax striatellus), although small number of insects on the hills were recorded. Relatively small number of white-backed planthopper (Sogatella furcifera) was occured in the BPMC and Diazinon treated plots. BPMC and Carbofuran were highly effective against the brown planthopper (Nilaparvata lugens) to 80 days after treatment. Incidence of dwarf virus disease was least in the plots of Carbofuran treatment. The highest grain yield was recorded in the plots treated with Carbofuran, and it seemed to be related with good protection from the dwarf virus disease and leaf-and plant-hoppers.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.216-233
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• 2020

This study set out to review tomb culture in the Gyeongju region during the Bronze Age, and also examine the patterns of dolmens during their end phase. For these purposes, the study analyzed 18 tomb relics from the Bronze Age and nine from the early Iron Age. Gyeongju belongs to the Geomdan-ri cultural zone. Approximately 120 tombs from the Bronze Age have been excavated in the Gyeongju region. There are fewer tombs than dwellings in the region, which is a general characteristic of the Geomdan-ri cultural zone. Although the number of tombs is small, the detailed structure of the dead body is varied. During the Bronze Age, tombs in the Gyeongju region were characterized by more prolific construction of pit tombs, dolmens with boundaries, and stacked stone altars than were the cases in other areas. There is a great possibility that the pit tombs in the Gyeongju region were influenced by their counterparts in the northeastern parts of North Korea, given the spindle whorl artifacts buried at the Dongsan-ri sites. Dolmens with boundaries and stacked stone altars are usually distributed in the Songguk-ri cultural zone, and it is peculiar that instances of these are found in large numbers in the Gyeongju region as part of the Geomdanri cultural zone. Even in the early Iron Age, the building of dolmens with boundaries and stacked stone altars continued in the Gyeongju region under the influence of the Bronze Age. A new group of people moved into the area, and they crafted ring-rimmed pottery and built wooden coffin tombs. In the early Iron Age, new rituals performed in high places also appeared, and were likely to provide venues for memorial services for heavenly gods in town-center areas. The Hwacheon-ri Mt. 251-1 relic and the Jukdong-ri relic are ruins that exhibit the aspect of rituals performed in high places well. In these rituals performed in high places, a stacked stone altar was built with the same form as the dolmens with boundaries, and a similar rock to the cover stone of a dolmen was used. People continued to build and use dolmens with boundaries and stacked stone altars while sustaining the Bronze Age traditions, even into the early Iron Age, because the authority of dolmens was maintained. Some dolmens with boundaries and stacked stone altars, known as being Bronze Age in origin, would have continued to be used in ritual practices until the early Iron Age. Entering the latter half of the second century B.C., wooden coffin tombs began to propagate. This was the time when the southern provinces, including the Gyeongju region, were included in the East Asian network, with the spread of ironware culture and the arrival of artifacts from central China. Around this time, dolmen culture faded into history with a new era beginning in its place.