• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.331-337
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• 2015

By comparing and evaluating the neutron dose when running cyclotron in fixed type measuring machine and portable type measuring machine, we performed this study to see if there is any difference between the doses in both measuring devices. We performed correction 3 times for the portable type during the experiment. We measured the values 12 times for each correction, so total 36 times by using the fixed type and portable type once every 2 weeks from June 2012 to February 2014. The statistics for the portable type and fixed type for each experiment showed 0.186, 0.511, and 0.057, which are not statistically significant. Therefore, we have come to the conclusion that unless there is deviation based on the correction period of the portable type, correction of fixed type wouldn't be necessary. Also, reduction of social costs may be achieved if we install an alarm meter, which is relatively low priced compared to the high cost neutron measuring machine, when detecting higher level than the interested standard level.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.3
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• pp.72-83
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• 2000

This paper presents the implementation of the position control system for 3 phase induction motor using reaching mode controller and neural networks. The reaching mode controller is used to bring the position error and speed error trajectories toward the sliding surface and to train neural networks at the first time. The structure of the reaching mode controller consists of the switch function of sliding surface. And feedforward neural networks approximates the equivalent control input using the reference speed and reference position and actual speed and actual position measured form an encoder and, are tuned on-line. The reaching mode controller and neural networks are applied to the position control system for 3 phase induction motor and, are compared with a PI controller through computer simulation and experiment respectively. The results are illustrated that the output of reaching mode controller is decreased and feedforward neural networks take charge of the main part for the control action, and the proposed controllers show better performance than the PI controller in abrupt load variation and the precise control is possible because the steady state error can be minimized by training neural networks.

• Journal of the Korean Vacuum Society
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• v.9 no.2
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• pp.172-178
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• 2000

We developed the model equations to investigate the particle movement and growth theoretically in a-Si plasma CVD reactor, where those particles act as the source of contamination. We included the effects of fluid convection, particle diffusion and external forces (ion drag force, electrostatic force and gravitational force) onto the particles to analyze the movements of particles in plasma reactor. Taking into account the particle charge distribution, the particle growth by coagulation between the charged particles was investigated. Most of those particles are located in the region near the sheath boundaries by the balance between the ion drag and electrostatic forces. The particle concentrations in the sheath region and in the bulk plasma region are almost zero. The sizes of the predator particles increase with time by the coagulation with protoparticles and, as a result, the surface area and the average charge of predator particles also increase with time.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.2
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• pp.157-165
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• 2002

This paper presents the implementation of the speed control system for 3 phase induction motor using PD controller and neural networks. The PD controller is used to control the motor and to train neural networks at the first time. And neural networks are widely used as controllers because of a nonlinear mapping capability, we used feedforward neural networks(FNN) in order to simply design the speed control system of the 3 phase induction motor. Neural networks are tuned online using the speed reference, actual speed measured from an encoder and control input current to motor. PD controller and neural networks are applied to the speed control system for 3 phase induction motor, are compared with PI controller through computer simulation and experiment respectively. The results are illustrated that the output of the PD controller is decreased and feedforward neural networks act main controller, and the proposed hybrid controllers show better performance than the PI controller in abrupt load variation and the precise control is possible because the steady state error can be minimized by training neural networks.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.413-424
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• 2003

Up to now it has been widely conceived that mariner's compass was introduced to Europe from China via the Arabic people. But the proofs to support the above orthodox dissertation have not been found yet. In general it has been approved that the Chinese used the compass for navigation in the 11th century and European did in the 12th century. During the above period the communication between the Europe and the China was made only by the mediation of the Arabic people. But it is known that the beginning of Arabic people's compass usage was one century later than that of the European. It may raise a historical question about ‘was mariner's compass introduced to Europe from China via the Arabic people\ulcorner’ In this paper the authors tried to prove the simultaneity of the mariner's compass usage by the European with the Chinese by reviewing historical materials and modern researches. The results are as following; The first, there is a strong similarity in the evolving steps of compass appliance of both civilizations, such as from using magnetized and pivoted needle to fixing card thereto. Second, the Chinese and the European started to use the mariner's compass almost at the same time, and they developed it independently.

• Research in Plant Disease
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• v.10 no.3
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• pp.159-166
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• 2004

This study were carried out to identify pathogens and determine the seasonal occurrence and chemical control of safflower (Carthamus tinctorius) diseases from 2000 to 2002 in Gyengbuk province, Korea. Major diseases of safflower were, anthracnose caused by Colletotricum acutatum in open field, and gray mold by Botrytis cinerea in rain sheltered plastic house. Other diseases occurred were powdery mildew caused by Sphaerotheca fuliginea, collar rot by Sclerotium rolfsii, leaf spot by Alternaria carthami and A. alternata, rust by Puccinia carthami, root-rot and stem-rot by Phytophthora cactorum, root-rot and wilt by Fusarium oxysporum and damping-off by Pythium ultimum. Seasonal occurrence of anthracnose on safflower has begun from late April, and increased until harvesting, especially rapid increased after rainfall during stem elongation season that is from May to June. In open fields, maximum incidence of anthracnose was 67 ％ in late July. But in rain-sheltered plastic house, it was very low, about 5％ in July. Gray mold caused by Botrytis cinerea was most important disease in rain-sheltered plastic house cultivation. Maximum incidence of gray mold on floral head was 27.4％, whereas other diseases occurred below 1 ％. In the test of the chemical control of the safflower anthracnose, metiram WP, carbendazim$.$kasugamycin WP and iminoctadintris$.$thiram WP were the highest controlling chemicals. In chemical control of gray mold, iminoctadintris$.$thiram WP, fluazinam WP and iprodion WP showed highest controlling effects.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.973-978
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• 2010

The emission of volatile organic compounds (VOCs) from building materials is one of great concerns due to maintain airtight condition of a building to reduce energy consumption, and it causes the deterioration of indoor air quality. Therefore, the emission characterization of VOCs from building materials is necessary to improve indoor air quality. Emission characteristics of VOCs from a plywood flooring that is one of the most commonly used materials in an under-heating system, and from an adhesive that is generally used to stick a plywood flooring to a concrete floor were investigated using an emission chamber test in this study. It was found that the VOCs emission factor was dependent upon and proportional to indoor temperature, and the emission characteristics were closely related to the existing places and conditions of VOCs sources inside the building materials. Maximum emission factors of hexane and toluene from building materials were generally observed at the beginning, however, only that of toluene from a plywood flooring was shown after 6 hours from the beginning. It could be considered that the existing place and condition of toluene source inside a plywood flooring could influence on the VOCs emission. From this study, bake-out time more than 72 hours could be recommended before moving in to avoid the exposure to high concentration of VOCs emitted from an under-heating system.

• Korean Journal of Social Welfare
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• v.62 no.3
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• pp.83-108
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• 2010

This study aims to estimate the trajectory of outpatient medical service use and examine what factors are associated with the trajectory among older adults 60 and over with specific focuses on age variations. Using the first three waves of the Korean Welfare Panel Study data, the trajectory and predictors were examined through the Latent Growth Curve Modeling and age variations were examined through the Multi-group Comparison Analyses. The research model was developed based on the Anderson Model. The results showed that study participants tend to increase outpatient medical service use with years. Individuals 75 or younger presented a much faster increasing rate of medical service use than those 75 and over. Similar to the findings of the previous studies, most predisposing factors, resource factors, and needs factors were found to be associated with the trajectory of outpatient medical service use. Needs factors were more closely associated with the medical service use trajectory than resource factors. With regard to age variations in predictors, few significant age variations were found. Based on the finding of the study, implications and future research directions were discussed.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.13-17
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• 1995

In order to induce haploid plant through pollen culture, pollens of Paeonia albiflora were cultured on MS liquid medium The development of micospore through pollen culture was examined The effect of low temperature (5$^{\circ}C$, 10 days) pretreatment on callus induction and embryogenesis in pollen culture was not evident Calli derived from pollen gave rise to globular embryos when transferred onto solid medium containing 0.5 mg/, 2,4-L. The effect of low temperature pretreatment and medium. combination to pollen viability was unrecognized. Pollen viability was reduced as the culture proceeded.

• 한국해양학회지
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• v.25 no.3
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• pp.131-134
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• 1990

Estimates of larval mortality for many marine fishes are based on field collections from several consecutive ichthyoplankton surveys, assuming that the surveys have covered the entire areas of larval habitats. The oceanic environment, however, is so dynamic and complicated that planktonic forms cannot stay within a confined area for a prolonged period. This note is prepared as a more detailed explanation of the estimates of fish larval mortality in the oceanic dispersing system, as a supplement of Kim and Bang (1990).