• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.905-910
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• 2013

This study was performed to determine the influence of pig breed and gender on the ultimate pH and physicochemical properties of pork. The correlations between pH and pork quality traits directly related to carcass grade, and consumer's preference were also evaluated. The pH and meat grading scores for cold carcasses of 215 purebred pigs (Duroc, Landrace, and Yorkshire) from four different farms were obtained. Meat quality parameters of the pork loin were analyzed. Duroc and female animals were more affected compared to other breeds and male pigs. Duroc animals had the highest ultimate pH, carcass back fat thickness, marbling scores, yellowness, and fat content (p<0.05). Landrace pigs had the highest color lightness and cooking loss values (p<0.05). Among all trait parameters, marbling scores showed the highest significant differences when evaluating the impact of breed and gender on meat quality characteristics (p<0.001). Ultimate pH was positively correlated with carcass weight (0.20), back fat thickness (0.19), marbling score (0.17), and color score (0.16) while negatively correlated with cooking loss (-0.24) and shear force (-0.20). Therefore, pork samples with lower ultimate pH had lower cooking loss, higher lightness, and higher shear force values irrespective of breed.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.64-70
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• 2003

This paper suggests a systematic methodology to predict chip forms using the experimental design technique and the neural network. Significant factors determined with ANOVA analysis are used as input variables of the neural network back-propagation algorithm. It has been shown that cutting conditions and cutting tool shapes have distinct effects on the chip forms, so chip breaking. Cutting tools are represented using the Z-map method, which differs from existing methods using some chip breaker parameters. After training the neural network with selected input variables, chip forms are predicted and compared with original chip forms obtained from experiments under same input conditions, showing that chip forms are same at all conditions. To verify the suggested model, one tool not used in training the model is chosen and input to the model. Under various cutting conditions, predicted chip forms agree well with those obtained from cutting experiments. The suggested method could reduce the cost and time significantly in designing cutting tools as well as replacing the“trial-and-error”design method.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.155-158
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• 2002

In general, TVC(Thermal Vapor Compressor) is used to boost/compress a low pressure vapor to a higher pressure for further utilization. The one-dimensional method is simple and reasonably accurate, but cannot realize the detail as like the back flow and recirculation in the mixing chamber, viscous shear effect, and etc. In this study, the axisymmetric How simulations have been performed to reveal the detailed flow characteristics for the various ejector shapes. The Navier-Stokes and energy equations are solved together with the continuity equation In the compressible flow fields. The standard $k-{\epsilon}$ model is selected for the turbulence modeling. The commercial computational fluid dynamic code FLUENT software is used for the simulation. The results contain the entrainment ratio under the various motive, suction and discharge pressure conditions. The numerical results are compared with the experimental data, and the comparison shows the good agreement. The three different flow regimes (double chocking, single chocking and back flow) have been clearly distinguished according to each boundary pressure values. Also the effects of the various shape variables (nozzle position, nozzle outlet diameter, mixing tube diameter, mixing tube converging angle, and etc.) are quantitatively discussed.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.10
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• pp.131-136
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• 2007

In this paper, we estimated the effects of different color stimulation on the cognitive function of human quantitatively. For the stimulations we used color lights with 6 color filters such as red, yellow, green, blue, violet and white. The experiment was performed in a soundproof chamber. 50 young male and female subjects were participated in the experiment. To find the appropriate color cognitive function, the endogenous visuospatial attention task(EVAT) and one back working memory task(OWMT) were performed. The reaction time and accuracy degree were measured. The results showed that the reaction time of EVAT was the fastest and the accuracy degree of attention task was the highest in green environment. The reaction time of OWMT was the fastest in yellow and the accuracy degree of memory task was the highest in blue. For physiological parameters, we measured electrocardiogram(ECG) and HRV spectrum analysis, HF/LF color environment. These results can be used as an indicator in the design of color environment and clinical applications.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.88-94
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• 2012

Development trend of modern HSDI diesel engine is now focusing on low fuel consumption and emission because of strong interest in global environmental protection. Two big branches of criteria for modern diesel engine development are down sizing and down speeding. Down sizing keeps engine operation condition to the direction of higher load and thus pursuing for better thermal efficiency. But this may cause degraded vehicle dynamic performance because of reduced back up torque. Down speeding keeps engine operation condition to the direction of slightly higher load and lower engine speed. Therefore reduction of back up torque can be limited within flat torque area. This study analyzed fuel economy effect of down speeding on a vehicle powered by HSDI diesel engine in aspect of engine friction work, intake and exhaust pumping work, exhaust hat loss and thermal loss of fuel leakage of fuel injection system. Contribution factor of each engine and vehicle related parameters under basic and down speeding condition were compared and work balance of down speeding during NEDC was analyzed.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.39-47
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• 2008

In this research, a web-based design support system is constructed for the design process of automotive steel pulley to gather engineering knowledge from pulley design data. In the design search module, a clustering tool for design data is proposed using K-means clustering algorithm. To obtain correlational patterns between design and FEA (Finite Element Analysis) data, a Multi-layer Back Propagation Network (MBPN) is applied. With the analyzed patterns from a number of simulation data, an estimation of minimum von mises can be provided for given design parameters of pulleys. The case study revealed fast estimation of minimum stress in the pulley within 12% error.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.93-98
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• 1993

In the ternary system of $CaF_2-CaO-P_2O_5$. Apatite$(Ca_{10}(PO_4)_6F_2)$ single crystal having a congruent point was grown by FZ process. The atmospheric condition was kept by oxygen blowing. Adjusting the growth parameters of rotation rate, growth rate and gas amount, we tried to find the optimum growth condition. By partly substituting Ca as Co element, the absorption of infrared is increased and the color effect was observed. Using the Laue back reflection, XRD and FTIR analysis, the characterization of the crystal was carried out.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.370-376
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• 2009

The influence of magnetic saturation on electromagnetic field distribution in both a permanent-magnet direct-current (PMDC) motor and a field-winding (wound-field) direct-current (FWDC) motor, with the same output mechanical power, has been studied. In this paper, an approximate analytical method and time-stepping Finite Element Method (FEM) are used for prediction of Back-EMF and electromagnetic torque. No-load and rotor-lucked conditions, according to experimental measurements, and the FEM and analytical method studies of the motors have been considered. A sensitivity analysis has also been successfully accomplished on the major design parameters that affect motor performance. At last, these two DC motors are compared, in spite of their differences, on the basis of measured output characteristics.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.119-128
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• 1994

Until recently, Stamping tool manufacturing depend on skilled designers and technicians, because it has many parameters. So, Try-out time not controlled. We now apply CAE, preliminary experiment, material database and automated stain measurement in stamping tool manufacturing for concurrent engineering that decreases product development circle time, saves cost, improves product reliability. Automated strain analysis and measurement environment gives very accurately informations to technicians of stamping tool manufacturing. They analysed the part in problem and appled to results in Try-out step.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.660-664
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• 2004

The indirect rotor position detection method using terminal voltage of brushless DC motor (BLDCM) requires simple control circuit, and has wide speed range of sensorless operation. However, because the substantial phase difference exists between real back emf and terminal voltage, the existing indirect detection method using analog filter which is affected by frequency, speed, and load sensitively cannot be synchronized with current, in the end, it advances or delays. This paper presents new analog filter circuit design for rotor position estimation in order to solve the problem, and proposes novel sensorless operation method which is stable even in high speed range and not influenced by parameters with analysis on phase difference by load and speed. Moreover, the appropriateness of the proposed sensorless drive in this paper is verified and analyzed by experimentation.