• Smart Structures and Systems
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• v.15 no.1
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• pp.227-244
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• 2015

This study develops a two stage procedure to identify the structural damage based on the optimized artificial neural networks. Initially, the modal strain energy index (MSEI) is established to extract the damaged elements and to reduce the computational time. Then the genetic algorithm (GA) and artificial neural networks (ANNs) are combined to detect the damage severity. The input of the network is modal strain energy index and the output is the flexural stiffness of the beam elements. The principal component analysis (PCA) is utilized to reduce the input variants of the neural network. By using the genetic algorithm to optimize the parameters, the ANNs can significantly improve the accuracy and convergence of the damage identification. The influence of noise on damage identification results is also studied. The simulation and experiment on beam structures shows that the adaptive parameter selection neural network can identify the damage location and severity of beam structures with high accuracy.

• Journal of Wind Energy
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• v.14 no.3
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• pp.34-42
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• 2023

The reduction of operation and maintenance (O&M) costs is a critical factor in determining the competitiveness of wind energy. Predictive maintenance based on the estimation of remaining useful life (RUL) is a key technology to reduce logistic costs and increase the availability of wind turbines. Although a mechanical component usually has sudden changes during operation, most RUL estimation methods use the trend of a state index over the whole operation period. Therefore, overestimation of RUL causes confusion in O&M plans and reduces the effect of predictive maintenance. In this paper, two RUL estimation methods (load based and data driven) are proposed for the bearings of a wind turbine with the results of trend classification, which differentiates constant and increasing states of the state index. The proposed estimation method is applied to a bearing degradation test, which shows a conservative estimation of RUL.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.7
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• pp.917-925
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• 2014

An accurate feed formulation is essential for optimizing feed efficiency and minimizing feed cost for swine and poultry production. Because energy and amino acid (AA) account for the major cost of swine and poultry diets, a precise determination of the availability of energy and AA in feedstuffs is essential for accurate diet formulations. Therefore, the methodology for determining the availability of energy and AA should be carefully selected. The total collection and index methods are 2 major procedures for estimating the availability of energy and AA in feedstuffs for swine and poultry diets. The total collection method is based on the laborious production of quantitative records of feed intake and output, whereas the index method can avoid the laborious work, but greatly relies on accurate chemical analysis of index compound. The direct method, in which the test feedstuff in a diet is the sole source of the component of interest, is widely used to determine the digestibility of nutritional components in feedstuffs. In some cases, however, it may be necessary to formulate a basal diet and a test diet in which a portion of the basal diet is replaced by the feed ingredient to be tested because of poor palatability and low level of the interested component in the test ingredients. For the digestibility of AA, due to the confounding effect on AA composition of protein in feces by microorganisms in the hind gut, ileal digestibility rather than fecal digestibility has been preferred as the reliable method for estimating AA digestibility. Depending on the contribution of ileal endogenous AA losses in the ileal digestibility calculation, ileal digestibility estimates can be expressed as apparent, standardized, and true ileal digestibility, and are usually determined using the ileal cannulation method for pigs and the slaughter method for poultry. Among these digestibility estimates, the standardized ileal AA digestibility that corrects apparent ileal digestibility for basal endogenous AA losses, provides appropriate information for the formulation of swine and poultry diets. The total quantity of energy in feedstuffs can be partitioned into different components including gross energy (GE), digestible energy (DE), metabolizable energy (ME), and net energy based on the consideration of sequential energy losses during digestion and metabolism from GE in feeds. For swine, the total collection method is suggested for determining DE and ME in feedstuffs whereas for poultry the classical ME assay and the precision-fed method are applicable. Further investigation for the utilization of ME may be conducted by measuring either heat production or energy retention using indirect calorimetry or comparative slaughter method, respectively. This review provides information on the methodology used to determine accurate estimates of AA and energy availability for formulating swine and poultry diets.

• Korean Journal of Mathematics
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• v.6 no.1
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• pp.77-85
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• 1998

In this paper we study the Hessian at critical points of energy function on Teichm$\ddot{u}$ller space T(R) and apply it to the index of minimal surfaces.

• The Korean Journal of Food And Nutrition
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• v.11 no.6
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• pp.647-686
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• 1998

The purpose of this study was to investigate selected nutrient intakes, dietary atherogenesity, energy balance and activity level of college students. One hundred and thirty onoe students (61 males and 70 females) made their three-day dietary records and one-day activity records along with one-day dietary records. BMI of the surveyed students was 22.33 for males and 20.28 for females. Average calorie intakes of male and female students was respectively 2166.20kcal and 1793.60kcal. Females had slightly higher fiber intakes than males in terms of fiber g/1000kcal. Carbohydrate, protein and fat ratios in energy composition of males and females were respectively 56.62 : 15.33 : 24.70 and 57.64 : 16.49 : 25.79. Average cholesterol intakes of male and female students were 295.66mg and 259mg respectively. The male showed higher saturated fat intake. and had higher atherogenic indices of diets such as cholesterol index(CI) and cholesterol-saturated fat index(CSI) than the female. Males spent an average of 1039.00 kcal/day compared to females of 687.93 kcal/day for all physical activities. Most students participated in light (100% of males and females) and moderate (33% of males and 3% of females) activities level. Few students spent time at severe and very severe activity level. Seventeen of the 131 students were in positive energy balance whereas 83% were in negative balance. Both genders with positive energy balance tended towards smaller weight and BMI, and larger food intakes than those with negative energy balance. Students with positive energy balance had higher saturated fat intakes and dietary atherogenic scores of CI and CSI than the counterparts with negative energy balance. Males with positive energy balance had decreased physical activity and daily energy expenditure whereas increased food and saturated fat intakes. Females with positive energy balance had singificantly increased food, saturated fat and sugar intakes.

• Journal of Distribution Science
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• v.12 no.3
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• pp.75-83
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• 2014

Purpose - The oil price affects company value, which is the present value of the expected cash flow, by affecting the discount rate and cash flow. This study examines the nonlinear relationships between oil price and stock price using the AlphaShares Chinese Volatility Index as the threshold. Research design, data, and methodology - Data comprise daily closing values of the Shanghai Stock Exchange Composite Index, Shenzhen Stock Exchange Composite Index, and Hang Seng Index of ChinaWest Texas Intermediate crude oil spot price and AlphaShares Chinese Volatility Index from May 25, 2007 to May 24, 2012. The Threshold Error Correction Model is used. Results - The results demonstrate different relationships between the stock price index and oil price under different investor sentiments; however, the stock price index and oil price could adjust to a long-term equilibrium the long-term causality tests between them were all significant. Conclusions - The relationship between the WTI and HANG SENG Index is more significant than the Shanghai Composites Index and Shenzhen Composite Index, when using the AlphaShares Chinese Volatility Index (ASC-VIX) as the investor sentiment variable and threshold.

• Journal of Nutrition and Health
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• v.43 no.5
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• pp.500-512
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• 2010

The relationship between food and nutrient intake, glycemic index (GI), glycemic load (GL), and body weight was investigated with high school girls residing in Seoul. As subjects, 159 girls were divided into a normal weight (NW) group (18.5 kg/$m^2$ $\leq$ BMI < 23 kg/$m^2$, n = 110) and an overweight (OW) group (BMI $\geq$ 23kg/$m^2$, n = 49) by body mass index (BMI). The food and nutrient intake data obtained by the 3-day food record were analyzed by Can pro 3.0 software. Anthropometric measurements were collected from each subject. Daily dietary GI (DGI) and dietary GL (DGL) were calculated from the 3-day food record. Body weights and BMI of NW were 52.4 kg and 20.4 kg/$m^2$ and those of OW were 65.2 kg and 25.4 kg/$m^2$, respectively. Total food, animal food, and other food intakes of NW were higher than those of OW, and vegetable food intakes of NW were lower than those of OW. Sugars intake of NW was significantly higher than OW. Nutrient intakes were not different between the two groups. Dietary fiber, calcium, and folate intakes of NW and OW were under 65% of the dietary reference intakes (DRIs). Major food sources of energy intake for both groups were rice, pizza, ice cream, pork, instant noodle, and chicken. Mean adequacy ratio (MAR), an index of overall dietary quality, was higher in NW (0.82) than in OW (0.80). Mean daily DGI of NW and OW was 66.5 and 66.4, respectively. Mean daily DGL of NW and OW was higher in NW (162.0) than in OW (155.9). DGI and DGL adjusted to energy intake were not significantly correlated with anthropometric data.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.70-74
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• 2004

There is a need to have a dredging index for decision of contaminated sediments dredging. Some differences from nation to nation were found in sediment quality guideline being applied by several nations because of economic level, environmental nature, and multiple uses. Therefore, it is not reasonable to adapt one guideline to be applied to sediments dredging. In this study, we developed dredging index by combining four numerical sets of sediment quality judgement into a quadrodiagram for prudential decisions. This newly developed dredging index was applied to the data obtained from Masan Bay before and after the dredging process. The quadrodiagrams of DI give us a nice graphical comparison and numerical values to explain the relative dredging effect under the circumstances of continuous input loadings. When the guideline value of DI is determined for the judgement of dredging considering social and economic impacts on local community, the DI value will be a scientific and reasonable tool in deciding dredging area and dredging depth.

• Journal of Korean Physical Therapy Science
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• v.7 no.1
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• pp.285-294
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• 2000

80 persons who don't have past history of cardiopulmonary and neuromuscular disease. The results were as follow; 1. PCI(Physiological Cost Index) value without loading to ankle were significantly increased compared to 1kg, and 2kg (p<0.01). 2. Female Subjects showed more increased PCI value in without loading and lkg, 2kg loading compared to male subjects (p<0.01). 3. In every PCI condition the difference among height groups was observed (p<0.01). 4. The difference among weight groups in each PCI condition was observed (p<0.01). These results showed that energy consumption was increased according to loading on the ankle during gait so weight of orthosis or prosthesis must be considered when choosing them and during gait training with these ones.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.11a
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• pp.31-36
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• 1993

Three different methods were employed to measure the degree of aerial oxidation in coal and the resulting oxidation/weathering indices were applied to obtain kinetic parameters of aerial oxidation processes, The index (i.e., slurry pH, Free Swelling Index, weight gain) values were subjected to kinetic analysis based on power-law Arrhenius type reaction model. The results show that activation energy of the aerial oxidation in 20-29$0^{\circ}C$ is in the range of 12-16 ㎉/㏖ and the agreement among three techniques is remarkable. The first order kinetic model is suitable in describing low temperature aerial oxidation process, except in the FSI case where the zero order expression is the best one.