• The Journal of Information Technology
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• v.9 no.4
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• pp.65-74
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• 2006

The back propagation of neural networks has the problems of falling into local minimum and delay of the speed by the iterative learning. An algorithm to solve the problem and improve the speed of the learning was already proposed in[8], which updates the learning parameter related with the connection weight. In this paper, we propose the algorithm generating initial weight to improve the efficiency of the algorithm by offering the difference between the input vector and the target signal to the generating function of initial weight. The algorithm proposed here can classify more than 98.75% of the handwritten digits and this rate shows 30% more effective than the other previous methods.

• KDI Journal of Economic Policy
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• v.43 no.2
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• pp.81-101
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• 2021

This paper estimates the expectation-augmented Phillips curve, which explains inflation dynamics, in Korea. The phenomenon of low inflation in Korea has been going on for quite some time, in particular since 2012. During the Covid-19 crisis, due to low inflation expectations the operation of monetary policy was limited as the base rate approached the zero lower bound. The main objective of this paper is to estimate where and how tightly inflation expectations are anchored. It was found that long-term inflation expectations fell to around 1%, falling short of the inflation target, and that inflation expectations are strongly anchored to long-term expectations, which implies that the low inflation phenomenon is likely to extend into the future. The results also imply that even if inflation fluctuates due to temporary disturbances, it may converge to a level below the inflation target. The slight rebound of long-term expectations during the Covid-19 crisis suggests that the aggressive monetary policy may have contributed to improving economic agents' beliefs about the commitment of monetary authorities to inflation stability. This may also help long-term expectations gradually to approach the inflation target.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.183-184
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• 2021

Defects such as falling and cracking of tiles installed in the bathrooms of apartment houses are frequently occurring. Therefore, in order to solve this problem, the A/S cost of construction companies and consumer complaints are increasing. The causes of tile defects include problems such as the selection of tile adhesive and lack of adhesive strength, the carelessness of the installer, the base surface, and the absorption rate of the tile. Therefore, in this study, an adhesive construction method using tile adhesives with high resistance to deformation of floors and tiles was studied. In addition, the properties and construction methods of tile adhesives were evaluated.

• Journal of information and communication convergence engineering
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• v.22 no.3
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• pp.231-236
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• 2024

This paper presents a method used to identify partial discharge defects in cast-resin power transformers using a back-propagation algorithm. The Rogowski-type partial discharge (PD) sensor was designed with a planar and thin structure based on a printed circuit board to detect PD signals. PD electrode systems, such as metal protrusions, particle-on-insulators, delamination, and void defects, were fabricated to simulate the PD defects that occur in service. PD characteristics, such as rising time, falling time, pulse width, skewness, and kurtosis without phase-resolved partial discharge patterns, were extracted to intuitively analyze each PD pulse according to the type of PD defect. A backpropagation algorithm was designed to identify PD defects using a virtual instrument (VI) based on the LabVIEW program. The results show that the accuracy rate of back-propagation (BP) algorithm reaches over 92.75% in identifying four types of PD defects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1153-1160
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• 2010

The detection algorithm for loss of balance had three main parts: one for processing data, another for constructing an internal model, and a third for detecting the loss of balance. The part related to the internal model is the most important part of the algorithm. The purpose of this study is to evaluate the effect of variables associated with the internal model on the success rate of the algorithm. The internal model depends on the type of linearization adopted and the operating period of the algorithm. The design variables were evaluated by performing sensitivity analysis of the variables of the internal model in order to obtain the success rate of the algorithm. The results showed that the most sensitive variable was the period and the period of 0.3 s yielded the highest success rate of 97.1%. Further, the ranges of the design variables that can facilitate a success rate of over 95% are presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2364-2369
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• 2015

In this paper, the optimum RPM was suggested comparing rotor filling rate of RPM through the analysis of rotor's filling rate as studying and developing centrifugal-casting machine's method for high precision rotor in order to increase the related types of business's productivity. The result was similar to other result in industrial site, showing 99.47% of filling rate when rotational speeds are 600 rpm, so it is considered that if this result is conducted with additional research, it will be possible to plan a better process design. Besides, the optimum temperature of compact ladle was examined to produce high quality casting product through the analysis of compact ladle's conductivity. In the case of the heating device's absence using nicrome wire, Al solution solidifies falling drastically into $427^{\circ}C$. However, it is feasible to work over $427^{\circ}C$ which is the melting temperature of aluminium solution when the heating device of nicrome wire is included. It reveals that there is little temperature change.

• Quality Improvement in Health Care
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• v.3 no.1
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• pp.94-103
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• 1996

Background : Blood pressure is an important indicator in diagnosis and assessing treatment of a patient. Clinical staffs use blood pressure on the assumption that measured value is accurate and reliable. However, whether measured blood pressure is accurate has been rarely investigated in Korea. Objectives : The aims of this study are to evaluate clinical staffs' knowledge and technique as well as accuracy of sphygmomanometer. Also the program to improve the measurement is developed. Methods : Seventy-three registered nurses were asked nine multiple choice questions including Korotkoff sound, cuff size, and deflation rate. Simultaneously characteristics of nurses were examined, age, working place, duration of employment and academic degree. A testing videotape(Standardizing Measurement Video-Tutored Course) was used for evaluating the accuracy of measurement. Testees were to read and record the 12 cases of blood pressure measurement, watching a falling mercury column and hearing Korotkoff sounds. After 10 minutes' education, they were again tested with the same cases. Additionally, 83 mercury sphygmomanometers were checked to find defects such as inaccurate calibration and zero setting, leaky bladder, etc. Results: For the knowledge testing correct response rate was 41.1%. They were the lowest in selecting the proper cuff size and Korotkoff sound. In examining accuracy of blood pressure with videotape, nurses had 67.7% correct response rate. The correct response rate was significantly improved by a session of education. About 23% of sphygmomanometers was without discernable defects. Conclusion : The knowledge and skill of clinical staffs along with the accuracy of equipment have to be improved. A properly designed education program would contribute to the accuracy improvement of blood pressure measurement. Also, more concerns should be given to the precision and maintenance of equipment.

• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.381-393
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• 1993

This paper presents the experimental results on flooding of countercurrent flow in vertical multirod channels, which consists of falling water film and upward air flow. In particular, the effects of spacer grids, with and without mixing vane, and of blockage in the multirod bundle on the behaviour of flooding were investigated. The 5$\times$5 zircaloy tube bundle was used for the test section. The comparison of previous analytical models and empirical correlations with present data on flooding showed that the existing models and correlations predict much higher flooding curves. The spacer grid causes the lower flooding air flow rate to compare with the bare rod bundle. However, the mixing spacer grids need a higher flooding air flow rate for a constant liquid flow rate than the spacer grids without mixing vanes. The bundle containing blockages has the highest flooding air flow rate among the bundles with spacer grids and blockages. Empirical flooding correlations for the three types of test section have been made.

• Journal of Preventive Medicine and Public Health
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• v.37 no.3
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• pp.274-281
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• 2004

Objectives : This study was performed to investigate the injury rates and risk factors for preschool children in Daegu city and Kyungpook province. Method : A questionnaire survey about medically attended injuries during the preschool period was performed in nine primary schools located in Daegu city, Pohang city and Goryung County. The overall injury rate was estimated using person-year. The causes and patterns of the injuries, and their risk factors were examined. Result : A total of 469 medically attended injuries were reported in 330 of the 959 study subjects during the preschool period. The overall annual injury rate was 7.5 per 100 children. The injury rate increased sharply during the period from infant (2.4) to 1 year of age (7.5), and the peak injury rate (9.2) was reported for 5 year olds. The most common causes of injuries were falling (36.0%), followed by being struck by an object (23.7%), and traffic accidents (14.1%). Among the traffic accidents, 72.8% occurred while playing on the road, riding a bicycle or roller-skating. A proportional hazard model showed that males (hazard ratio=1.49, p<0.001 compared with female) and the mother's higher education level (hazard ratio of college or higher= 1.51, p=0.013; high school=1.32, p=0.085 compared with those of middle school or lower) were significant risk factors of childhood injury. Conclusion : The results of this study suggested that efforts for children's safety should be made, especially from the toddler stage, and in male children. To develop a more specific childhood injury prevention program, a surveillance system for injuries should be established. Further study of the relationship between mother's occupation and injury rates is also needed.

• Ocean and Polar Research
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• v.44 no.2
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• pp.127-137
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• 2022

This study examined the growth pattern and environmental factors affecting the growth of the halophyte, Suaeda japonica, which is prevalent on tidal flats in the west coast of Korea in order to calculate annual carbon production. Quantitative sampling was conducted every month for three years from 2018 to 2020 on salt marshes located on the southern coast of Ganghwa Island. In terms of annual density affected by the germination rate at first period, especially when air temperature for winter time was constantly below 0℃ for long periods of time, germination decreased and precipitation in summer also exerted an influence. In terms of annual growth with regard to length, the part below the ground grew rapidly in the beginning after budding, while the part above ground grew at a relatively steady rate at all times. With regard to biomass, the part below the ground also increased from April in a manner similar to length growth, but decreased drastically from September with leaves falling off and water loss occurring. The part above ground showed a rapid increase from the beginning of the rainy season. Size-frequency distribution revealed broader patterns after the rainy season as individual growth varied, but from September, it stopped at all year. High growth rates were recorded in the initial phase of growth after budding and growth was rapid, but growth declined in summer when biomass increased. The annual mean production based on growth rate was calculated at 352 gDWt/m²/yr, and the highest production was 519 gDWt/m²/yr in 2018, but it has decreased since 2019. Annual carbon production was at calculated 143.41 gC/m²/yr for Suaeda japonica in the vicinity of the southern coast of Ganghwa Island.