• Journal of the Korea Society of Computer and Information
• /
• v.21 no.8
• /
• pp.95-103
• /
• 2016

Food habit forming the basis for a lifetime of food and nutrient intake is established in early childhood and has an effect to the child's growth, sociality, and obesity. A variety of nutrition screening tools exists for assessing the health and nutrition status of children such as the Growth Curve, for determining if growth is appropriate. Body mass index(BMI) as a more reliable index of overweight to prevent childhood obesity, and Nutrition Quotient(NQ) and eating behaviors questionnaire for young children and parents to estimate their nutrient intake adequate or not. Such tools are mainly used by health practitioners, such as doctor and dietitian to provide nutrition intervention services to children at risk, especially and are not easy to use for general parents, who need assessment at any time and at any place. We propose Growth Assistance System for infants and children, which is possible to assess their physical condition, nutritional status, and eating behavior integrated. To be convenient and portable, it is implemented over the smartphone as an application. The system offers the growth charts, the BMI curves, NQ and eating behavior questionnaire to take a monitoring and the functionalities operate well. We hereby expect this system support the normal growth and development of infants and young children. And also support for the health practitioner (dietitians and nutritionists) to take a role in providing nutrition counseling and education to children needing nutrition services.

• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.4
• /
• pp.77-84
• /
• 2004

Active control is regarded as one of the most efficient and economic countermeasures to reduce excessive vibration of ship superstructure. However, it is difficult to find its practical application in real ships in spite that many studies on such systems have been done. In this study, for the practical use of an active control system to reduce ship superstructure vibration, we have developed an active vibration compensator consisting of a mechanical actuator having compact size and expected lifetime over 20 years, its control panel including exclusive signal processing and computing board, sensors to detect phase and vibration, and its operation software providing various user-interface functions. From the performance verification test of the system at a 5,500 TEU container carrier, we have confirmed the system could reduce ship superstructure vibration of a harmonic component of main engine rotating frequency up to 0.1 mm/s.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.3
• /
• pp.143-149
• /
• 2018

It has become ever harder to design reliable circuits with each nanometer technology node; under normal operation conditions, a transistor device can be affected by various aging effects resulting in performance degradation and eventually design failure. The reliability (aging) effect has traditionally been the area of process engineers. However, in the future, even the smallest of variations can slow down a transistor's switching speed, and an aging device may not perform adequately at a very low voltage. Therefore, circuit designers need to consider these reliability effects in the early stages of design to make sure there are enough margins for circuits to function correctly over their entire lifetime. However, such an approach excessively increases the size and power dissipation of a system. As the impact of reliability, new techniques in designing aging-resilient circuits are necessary to reduce the impact of the aging stresses on performance, power, and yield or to predict the failure of a system. Therefore, in this paper, a novel low power on-chip self-tuning circuit considering the aging effects has been proposed.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.1C
• /
• pp.97-108
• /
• 2012

This paper introduces a health monitoring system based on a wireless sensor network for weapon asset. This system can estimate the remaining lifetime and decide what should be done and when should it be done using the environmental conditions such as temperature, humidity and shock for weapon assets by sensor tag. And we describes its operating scenario and routing method for this system. Finally we introduce the developments of the sensor tag, portable reader, gateway and monitoring server.

• The Journal of the Korea Contents Association
• /
• v.17 no.9
• /
• pp.466-475
• /
• 2017

Various factors in daily life cause stress, which could stem from trivial or major events. Stress is not appeared at any time but is appeared over the lifetime. Therefore, it is necessary to conduct studies to identify ways to manage stress. In the present study, we developed an iris analysis-based system to diagnose and manage stress. By analyzing its correlation with the degree of stress measured using the iris diagnosis and a questionnaire, the user's degree of stress quantitates. The system proposed in this study can be used to measure the degree of stress experienced by the user, which can be an effective method for the early diagnosis and prevention of stress-related diseases.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.2
• /
• pp.635-642
• /
• 2014

The space charge behaviors of oil-paper insulation affect the stability and security of oil-filled converter transformers of traditional and new energies. This paper presents the results of the electrical aging of oil-impregnated paper under AC-DC combined voltages by the pulsed electro-acoustic technique. Data mining and feature extractions were performed on the influence of electrical aging on charge dynamics based on the experiment results in the first stage. Characteristic parameters such as total charge injection and apparent charge mobility were calculated. The influences of electrical aging on the trap energy distribution of an oil-paper insulation system were analyzed and discussed. Longer electrical aging time would increase the depth and energy density of charge trap, which decelerates the apparent charge mobility and increases the probability of hot electron formation. This mechanism would accelerate damage to the cellulose and the formation of discharge channels, enhance the acceleration of the electric field distortion, and shorten insulation lifetime under AC-DC combined voltages.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.666-672
• /
• 2008

Train wheels are the most important part of the high-speed rail system with supporting body, running stably and safely. Wheel exchange and fix plan is computed by the worker who managing entire Train Maintenance Process based on his know-how so that this system is losing its reliability and accuracy. And predicting of the wheel's lifetime is absolutely difficult matter because of uncertainty between trains like mileage of the type of trains, condition of operation, curve section and wheel's cutting pattern. Therefore workers always used to hold many wheels. For this reason, the cost of stock is soar when the level of stock was normal. If the stock is sufficient, the cost of stock will rise. On the other hand, If the stock is deficient, we would have trouble that the plan of the train maintenance process will be failed. Thus this paper aimed at application that "Wheel Managing System" which is able to predict wheel's life-cycle and demands under the RIMS(Rolling-Stock Information Maintenance System) with analysing wheel exchanging and cutting status considering economical or stable aspects.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.5
• /
• pp.357-363
• /
• 2021

Eco-friendly hybrid railroad propulsion system with fuel-cell and battery was suggested to reduce carbon dioxide gas and replace retired diesel railroads. Lithium-ion battery with high energy/power density and long lifetime is selected as the energy source at the battery side due to its excellent performance. However, the performance of lithium-ion batteries was affected by temperature, current rate, and operating condition. Temperature is known to be the most influential factor in changing battery parameters. In addition, appropriate thermal management is required to ensure the safe and effective operation of lithium-ion battery. Electro-thermal coupled model with varying parameter depends on temperature, and state-of-charge (SOC) is suggested to estimate battery temperature. The electric-thermal coupled model contains diffusion current using parameter identification by adaptive control algorithm when considering thermal diffusion effect. An experiment under forced convection was conducted using cylindrical cell and 18 parallel-connected battery module to demonstrate the method.

• Journal of the Mineralogical Society of Korea
• /
• v.24 no.1
• /
• pp.43-53
• /
• 2011

Health risk assessments for the abandoned asbestos mine were usually performed with activity-based sampling (ABS) method, which was not a effective tool for indexing health risk on an exact small area of mine. A newly proposed potential index of health risk (PIHR) was applied with proper spatial determination of geographical information system (GIS) to assess quantitatively health risks. A new trial was applied to a certain abandoned mine in Boryong as follows: A high grade area of PIHR was estimated 7.8% of the whole area of the mine (about 27.3 ha). Based on US EPA IRIS (integrated risk information system) model considering lifetime excess cancer risk (LECR), the health risk assessment indicated that the high grade area increased from 3.0 ha through 12.9 ha to 19.5 ha with an increase of asbestos contents in soil from 0.36% (1E-04 level) through 0.1% (3E-05 level) to 0.04% (1E-05 level). These results can be effectively applied to determine reclamation area of the abandoned asbestos mine.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5487-5495
• /
• 2012

The important issue that applies security key are secure rekeying, processing time and cost reduction. Because of sensor node's limited energy, energy consumption for rekeying affects lifetime of network. Thus it is necessary a secure and efficient security key management method. In this paper, I propose an energy efficient group-based cluster key management (EEGCK) in the large scale sensor networks. EEGCK uses five security key for efficient key management and different polynomial degree using security fitness function of sector, cluster and group is applied for rekeying and security processing. Through both analysis and simulation, I also show that proposed EEGCK is better than previous security management method at point of network energy efficiency.