• International Journal of Fluid Machinery and Systems
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• v.8 no.4
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• pp.274-282
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• 2015

This paper deals with the influence of leakage flow existing in SHF pump model on the analysis of internal flow behaviour inside the vane diffuser of the pump model performance using both experiments and calculations. PIV measurements have been performed at different hub to shroud planes inside one diffuser channel passage for a given speed of rotation and various flow rates. For each operating condition, the PIV measurements have been trigged with different angular impeller positions. The performances and the static pressure rise of the diffuser were also measured using a three-hole probe. The numerical simulations were carried out with Star CCM+ 9.06 code (RANS frozen and unsteady calculations). Some results were already presented at the XXth IAHR Symposium for three flowrates for RANS frozen and URANS calculations. In the present paper, comparisons between URANS calculations with and without leakages and experimental results are presented and discussed for these flow rates. The performances of the diffuser obtained by numerical calculations are compared to those obtained by the three-holes probe measurements. The comparisons show the influence of fluid leakages on global performances and a real improvement concerning the efficiency of the diffuser, the pump and the velocity distributions. These results show that leakage is an important parameter that has to be taken into account in order to make improved comparisons between numerical approaches and experiments in such a specific model set up.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.155-162
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• 2008

The quality of the fruits is measured by a lot of parameters. The grader of the fruits to measure the size of them is using the rotation drum method. Therefore when we classify the size of the fruits, they will be damaged. Also the optical grader used for estimating the degree of the saccharinity will incur high cost for it. In the proposed system, to select the characteristics of the fruits, three cameras are used. Because the information such as the volume and the degree of the maturity is used to classify the fruits, the degree of the saccharinity can't be estimated itself, but the information such as the color and the damage of the fruits can be estimated. Therefore, because we don't need the digital image with high resolution, we can develop the grader system of the fruit with low cost. To evaluate the performance of the proposed system, we compared it with the sight estimation and then we classified the sample. The result shows the accuracy of 96.7%.

• PNF and Movement
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• v.16 no.1
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• pp.27-32
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• 2018

Purpose: This study examined changes in gait speed and stride length after an intervention involving simultaneous scapular and pelvic patterns of proprioceptive neuromuscular facilitation in a hemiplegic patient. Methods: A 58-year-old woman with left hemiplegia who had complained of slowness of gait speed and weakness of leg strength took part in an intervention involving scapular postdepression patterns on the affected side and pelvic postdepression patterns on the nonaffected side. The intervention was performed with the patient lying on her left side, in a half kneeling position, and in a standing posture. Rhythmic initiation was used for teaching the movements to the patient and improvement of kinesthesia, and a combination of isotonic was employed for increasing strength and irradiation of the scapula and pelvic movement. The intervention took place for 30 min. It was implemented twice a day, 5 days a week, for 3 weeks. After three repetitions, the average time taken to complete the 10-m walk test (10 MWT), in addition to stride length, was measured to determine gait speed. Results: After the 3-week program, the patient's performance in the 10 MWT improved from 21.7sec to 17.1sec, and her stride length improved from 31.4cm to 38.7cm. Conclusion: The results showed that trunk movement exercise, especially coordinative movements of the scapula and pelvis can improve gait speed and stride length by increasing trunk stability and mobility. A combination of pelvic and scapular patterns can facilitate trunk rotation, thereby improving gait speed and stride length.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.335-342
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• 2013

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.117-117
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• 2016

Total ankle replacement (TAR) is a visible option in the surgical treatment of degenerative or inflammatory diseases of ankle joint. it is attributed to the current TAR which has improvements in surgical technique, uncemented implant fixation and minimally constrained articulation. In the clinical result, they can show promised surgical result when compared to earlier attempts in TAR. However, TAR is still not as successful as total knee replacement (TKR) or total hip replacement (THR), it needs to be note that there are limitations in concerning of long term performance of TAR, the high failure rate still associated with wear of the PE (polyethylene) component that has related with their material property and surface roughness. The aim of this study was to introduce the tribology characteristics of total ankle joint prosthesis with one of TDR model which was fabricated to try multi-axis wear test as a region of motion in ankle joint. The wear specimen of TDR was prepared with Ti-6Al-4V alloy and UHMWPE (ultra-high molecular weight polyethylene) for tibia-talus and bearing component, respectively. A wear test was carried out using a Force 5 (AMTI, Massachusetts, US) wear simulator which can be allowed to move in three axis to flexion-extension ($+3^{\circ}{\sim}-6^{\circ}$), internal-external axial rotation (${\pm}5^{\circ}$), as well as sinusoidal compressive load (1.6 kN, R=10). All tests were performed following standard ISO 14243, wear rate was calculated with weight loss of UHMWPE bearing while the specimen has tested at certain cycles. As based on the preliminary results, wear rate of UHMWPE bearing was $7.9{\times}10^{-6}mg/cycles$ ($R^2=0.86$), calculated loss weight until $10^7cycles$ was 79 mg, respectively.

• Journal of Powder Materials
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• v.13 no.1 s.54
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• pp.62-67
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• 2006

Friction welding of $Al_2O_3$ particulate reinforced aluminum composites was performed and the following conclusions were drawn from the study of interfacial bonding characteristics and the relationship between experimental parameters of friction welding and interfacial bond strength. Highest bonded joint efficiency (HBJE) approaching $100\%$ was obtained from the post-brake timing, indicating that the bonding strength of the joint is close to that of the base material. For the pre-brake timing, HBJE was $65\%$. Most region of the bonded interface obtained from post-brake timing exhibited similar microstructure with the matrix or with very thin, fine-grained $Al_2O_3$ layer. This was attributed to the fact that the fine-grained $Al_2O_3$ layer forming at the bonding interface was drawn out circumferentially in this process. Joint efficiency of post-brake timing was always higher than that of pre-brake timing regardless of rotation speed employed. In order to guarantee the performance of friction welded joint similar to the efficiency of matrix, it is necessary to push out the fine-grained $Al_2O_3$ layer forming at the bonding interface circumferentially. As a result, microstructure of the bonded joint similar to that of the matrix with very thin, fine-grained $Al_2O_3$ layer can be obtained.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.64-76
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• 1998

In this paper, we propose the dynamic modeling, path planning and tracking algorithms of 4-wheeled 2-d.o.f.(degree of freedom) mobile robot(WMR). The gaussian functions are applied to design the smooth path of WMR. To calculate the WMR position in real time, we use three components of inertial measurement units(IMU). These units have initial error because of the rotation rate of earth, gravity acceleration and so on. Therefore we derive the initial error model of IMU, and compare the fitness diagnosis about probability characteristics of real data adn estimated data. The performance of IMU with error model and Kalman filter is compared to that without filter and error model. The simulation results show that the proposed dynamic model, path planning and tracking algorithms are more useful than the conventional control algorithm.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.260-267
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• 2017

Quantum-inspired Genetic Algorithm (QGA) is a probabilistic search optimization method combined quantum computation and genetic algorithm. In QGA, the chromosomes are encoded by qubits and are updated by quantum rotation gates, which can achieve a genetic search. Asset-based weapon target assignment (WTA) problem can be described as an optimization problem in which the defenders assign the weapons to hostile targets in order to maximize the value of a group of surviving assets threatened by the targets. It has already been proven that the WTA problem is NP-complete. In this study, we propose a QGA and a hybrid-QGA to solve an asset-based WTA problem. In the proposed QGA, a set of probabilistic superposition of qubits are coded and collapsed into a target number. Q-gate updating strategy is also used for search guidance. The hybrid-QGA is generated by incorporating both the random search capability of QGA and the evolution capability of genetic algorithm (GA). To observe the performance of each algorithm, we construct three synthetic WTA problems and check how each algorithm works on them. Simulation results show that all of the algorithm have good quality of solutions. Since the difference among mean resulting value is within 2%, we run the nonparametric pairwise Wilcoxon rank sum test for testing the equality of the means among the results. The Wilcoxon test reveals that GA has better quality than the others. In contrast, the simulation results indicate that hybrid-QGA and QGA is much faster than GA for the production of the same number of generations.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.325-330
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• 2017

Face recognition technology has been studied for decades and is being used in various areas such as security, entertainment, and mobile services. The main problem with face recognition technology is that the recognition rate is significantly reduced depending on the environmental factors such as brightness, illumination angle, and image rotation. Therefore, in this paper, we propose a robust face recognition against lighting variation using CNN which has been recently re-evaluated with the development of computer hardware and algorithms capable of processing a large amount of computation. For performance verification, PCA, LBP, and DCT algorithms were compared with the conventional face recognition algorithms. The recognition was improved by 9.82%, 11.6%, and 4.54%, respectively. Also, the recognition improvement of 5.24% was recorded in the comparison of the face recognition research result using the existing neural network, and the final recognition rate was 99.25%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.4
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• pp.607-616
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• 2014

Face recognition is a big challenge in surveillance system since different rotation angles of the face make the difficulty to recognize the face of the same person. This paper proposes a novel method to recognize face with different head poses by using 3D information of the face. Firstly, head pose estimation (estimation of different head pose angles) is accomplished by the POSIT algorithm. Then, 3D face image data is constructed by using head pose estimation. After that, 2D image and the constructed 3D face matching is performed. Face verification is accomplished by using commercial face recognition SDK. Performance evaluation of the proposed method indicates that the error range of head pose estimation is below 10 degree and the matching rate is about 95%.