• Journal of the Korean Society for Nondestructive Testing
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• v.12 no.3
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• pp.7-11
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• 1992

Accurate measurement of green density of compacted part in the powder metallurgy industry is rather fundamental but extremely important process that decide the quality of the sintered part. In case of green sheet P/M product, the green density as well as the distribution of the density must be examined for the same reasons. Currently in most cases, density measuring process is being performed applying conventional Archimedes principles. However this method is not only time-consuming but also often inaccurate because of the inherent nature of the process, such as part sectioning, closing of surface porosity with wax and weighing in air and in water. Therefore, it is necessary to develop a faster and more accurate method to measure the density of green sheet P/M product. In this work, a nondestructive density measurement device using gamma-ray absorption principles was constructed and the optimum condition for measuring green density of P/M sheet and its distribution was sought. The results showed that this method was very effective in terms of measuring time and accuracy.

• Journal of Drive and Control
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• v.19 no.2
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• pp.11-16
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• 2022

It is important to measure the excavator's work productivity that estimates the bucket's payloads on a process. If the bucket isn't filled at every working cycle, the excavator's operator has to drive the machine more to achieve his work quota. If bucket is filled over with the load, the other way around, the transferred object has to spread out on the workplace. That causes additional work to clean the site. This paper proposes a method that can estimate the bucket's payload to improve the excavator's work productivity. This method assumes that the excavator is a lumped mass system. And it uses a 3 points angle (boom link, arm link, swing) and 2 points pressure (boom cylinder's input port and output port) of measurable data. Depending on assumptions, the bucket's payload can be calculated by the payload's motion equation. And this suggested method can be verified by simple experiments.

• International Journal of Control, Automation, and Systems
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• v.3 no.4
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• pp.524-532
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• 2005

This paper concerns delay-dependent guaranteed cost control (GCC) problem for a class of linear state-delayed systems with norm-bounded time-varying parametric uncertainties. By incorporating the free weighing matrix approach developed recently, new delay-dependent conditions for the existence of the guaranteed cost controller are presented in terms of matrix inequalities for both nominal state-delayed systems and uncertain state-delayed systems. An algorithm involving convex optimization is proposed to design a controller achieving a suboptimal guaranteed cost such that the system can be stabilized for all admissible uncertainties. Through numerical examples, it is shown that the proposed method can yield less guaranteed cost than the existing delay-dependent methods.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.391-394
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• 2009

Asymmetrical and unbalanced features such as rotor blade of helicopter, actuator of hard-disk in personal computer are usually manufactured with composite materials. In this case, mass distributions and center of gravity of the parts are important because of their static balancing. Therefore in the manufacturing processes, it is needed to check out the exact data of weight and gravity center. In this study, it has been studied experimentally the balancing of laminated rotor blade by using multiple-point weighing method and lab-view system.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.100-108
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• 1999

This paper reviews some methods on evaluating the impacts of low input farming on profitability, environments and human health. Measuring diverse effects of low input farming on the environmental economic aspects of agriculture poses a challenge because of difficulty in placing the objective value judgement on those impacts. This Study attempts to identify the individual attributes of low input agriculture and to examine the method of consturcting a simple index after assessing its marketed or non-marketed values in numerical terms. Validity of integrating socio-economic value of low input agriculture, which might be measured by multiple criteria approach, into a single index can be criticized. However, it might be meaningful in that this study suggest the guidance for how to assess the environmental and economic value of low input agriculture by single criteria and the possibility of overcoming the controversial subjectivity in weighing the different impact criteria.

• Journal of Nutrition and Health
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• v.28 no.8
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• pp.717-726
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• 1995

This study was to investigate the validity of energy measurement system by using different body size and sex of rats and feed supplementation methods. There appeared no statistical differences in energy(AME, AMEn) utilization between male and female rats with average 200g body weight, and between male rat of 200g and 300g body weight. Glucose replacing corn in the basal diet or replacing diet itself at a level of 30% by weight appeared to have the same metabolizable energy value, suggesting that either methods to supplement test ingredient brought about the same results. Consequently, following suggestions could be made from results of present study : first, Sprague-Dawley rate of either sex weighing 200-300g may be used as an animal model to obtain in vivo metabolizable energy from dietary carbo-hydrates or sea foods. Second, the testing ingredients may be added at the expence of corn in the basal diet at 30% level.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.133-139
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• 2002

In precision instrumentation system, an A/D conversion of signal conditioning has been always suffered from some problems ; offset and drift voltage with environmental situation. This paper suggests a method of reducing the offset voltage and the drift error from the A/D conversion hardware using analog signal switching technique with specific operational amplifier circuits. Also, we have designed a hardware active filter and a software digital filter with Auto Zero Tracking algorithm for better dignal process of the our proposed weighing system. Software technique was performed to obtain the stable data from A/D converter. As a result of our experimental works, the proposed system is expected to be used in the industrial field where a high precision measurement is required.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.110-117
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• 1995

This study presents and algorithm and related techniques which could satisfy the important properties of check weighers and conveyor scales. The algorithm of Recursive Least Squares Regression is applied for the weighing system simulated as a dynamic model of the second order. Using the model and the algorithm, model parameters and then the mass being weighed can be determined from the step input. The performance of the algorithm was tested on a check weigher. Discussions were extended to the development of noise reduction techniques and to the lagged introduction of objects on the moving plate. It turns out that the algorithm shows several desirable features suitable for real-time signal processing with a microcomputer, which are high precision and stability in noisy environment.

• Journal of Nutrition and Health
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• v.27 no.6
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• pp.591-598
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• 1994

The longitudinal changes in transitional milk intakes and body weight of infants(18 boys, 10 girls) have been studied in the part of Kangwon Province from 7 days to 15 days postpartum. Milk intakes at 7, 10, 15 days postpartum were 474$\pm$155, 524$\pm$154 and 547$\pm$130g, respectively. The mean milk intakes were 515g from 7 to 15 days postpartum. Milk intakes of boys were significantly higher than those of girls. The transitional milk intakes per weight of infants appeared 147$\pm$41g/kg. The number of feed per day of boys were significantly higher than those of girls. Milk intakes per fed were 56$\pm$20g. The transitional milk intakes were affected by gestational period(p<0.05), maternal height(p<0.05) and mother's transitional milk yields (p<0.001). Infants transitional milk intakes were 82.6$\pm$17.0% of mothers transitional milk yields. Infants gained its weight 24.6, 40.1 and 39.0g/day at, 7, 10, 15 days postpartum, respectively.

• Journal of Nutrition and Health
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• v.25 no.5
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• pp.404-412
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• 1992

Iron intake and nutritional status of 99 female college students of Chungnam Natiional Unive-rsity were estimateed with dietary survey and measurement of hematological indices including the level of serum ferritin Food intake was measured using the weighing method and iron availability per meal was calculated according to Monsen and Hallberg. The average daily intakes of protein vitamin C. total iron and also total available amount of iron were higher than the Korean R.D.A. The blood indices for iron status however showed that iron status of the subjects was inade-quate. Furthermore the serum ferritin levels indicated marginal iron storage in 75% of the subjects.