• 한국공작기계학회논문집
• /
• 제17권6호
• /
• pp.118-123
• /
• 2008

Weakness process can be called ferrule array and epoxy filling process at connector manufacturing process, and a lot of problems happen as think as general manufacturing process at early investment. Wished to improve this and working environment mend of worker on childhood(planning phase) and problem that is happened at done ferrule array and epoxy injection by emphasis target. By ferrule sorting and Improvement of epoxy filling process, bring authoritativeness elevation of product by fraction defective decrease of product by sized work along with productivity elevation. On the other hand, working jigs are various in characteristics of optical connector manufacturing line. There have been lots of restriction in practice because the applicability of this system is only for single type model though the network should be smooth between lines. Thus, it is not only needed the recognition of necessity in industrial line but also the development of automation system arraying ferrule and filling epoxy in the manufacturing process. It is found that the present system development enhances productivity fairly and prevents industrial disaster in the optical connector manufacturing system.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2005년도 춘계학술대회 논문집
• /
• pp.115-124
• /
• 2005

This paper analyzes the problems that occurred in the magnification process for a fine input image and investigates a method to improve the problems. This paper applies a curve interpolation algorithm in CAD/CAM for the same test images with the existing image algorithm in order to improve the problems. As a result. the nearest neighbor interpolation. which is the most frequently applied algorithm for the existing image interpolation algorithm. shows that the identification of a magnified image is not possible. Therefore. this study examines an interpolation of gray-level data by applying a low-pass spatial filter and verifies that a bilinear interpolation presents a lack of property that accentuates the boundary of the image where the image is largely changed. The periodic B-spline interpolation algorithm used for curve interpolation in CAD/CAM can remove the blurring but shows a problem of obscuration, and the Ferguson's curve interpolation algorithm shows a more sharpened image than that of the periodic B-spline algorithm. For the future study, hereafter. this study will develop an interpolation algorithm that has an excel lent improvement for the boundary of the image and continuous and flexible property by using the NURBS. Ferguson's complex surface. and Bezier surface used in CAD/CAM engineering based on. the results of this study.

• Advances in aircraft and spacecraft science
• /
• 제6권4호
• /
• pp.333-348
• /
• 2019

Low fuel regression rate is the main drawback of hybrid rocket which should be overcome. One of the improvement techniques to this problem is usage of a solid fuel grain with a complicated geometry port, which has been promoted owing to the recent development of additive manufacturing technologies. In the design of a hybrid rocket fuel grain with a complicated geometry port, the understanding of fuel regression behavior is very important. Numerical investigations of fuel regression behavior requires a capturing method of solid fuel surface, i.e. gas-solid interface. In this study, level set method is employed as such a method and the preliminary numerical tool for capturing a hybrid rocket solid fuel surface is developed. At first, to test the adequacy of the numerical modeling, the simulation results for circular port are compared to the experimental results in open literature. The regression rates and oxidizer to fuel ratios show good agreements between the simulations and the experiments, after passing enough time. However, during the early period of combustion, there are the discrepancies between the simulations and the experiments, owing to transient phenomena. Second, the simulations of complicated geometry ports are demonstrated. In this preliminary step, a star shape is employed as complicated geometry of port. The slot number effect in star port is investigated. The regression rate decreases with increasing the slot number, except for the star port with many slots (8 slots) in the latter half of combustion. The oxidizer to fuel ratio increases with increasing the slot number.

• International Journal of Aeronautical and Space Sciences
• /
• 제18권1호
• /
• pp.154-164
• /
• 2017

This work conducts a validation study for the XH-59A helicopter using a rigid coaxial rotor system in order to establish the techniques of the conceptual design and performance analysis for the lift-offset compound rotorcraft. As a tool for conceptual design and performance analysis, NDARC (NASA Design and Analysis of Rotorcraft) is used for the present study. An assumed mission profile is considered for the conceptual design of the XH-59A. As a validation result of the design, the dimensions and weight of the XH-59A are appropriately designed when compared to the target values since the relative error is less than 0.5%. Then, performance analyses are conducted for the designed XH-59A model with and without auxiliary propulsion in hover and forward flight conditions. The present analyses show good validity since the prediction results compare well with both the flight test and previous analyses. Therefore, the techniques for the conceptual design and performance analysis of the lift-offset compound helicopter are overall considered to be appropriately established. In addition, this study investigates the influence of the lift-offset on the rotor effective lift-to-drag ratio of the XH-59A helicopter with auxiliary propulsion. As a result, the improvement of the rotor effective lift-to-drag ratio can be obtained by appropriately increasing the lift-offset in high-speed flight.

• 유통과학연구
• /
• 제18권1호
• /
• pp.47-57
• /
• 2020

Purpose: This study seeks to bridge between the research by Lawrence (1999) and Retegan (1992), where the focus of TQM on his studies rests on customer satisfaction. Whereas in this study trying to recompile TQM by involving the variables Innovation and competitive advantage to stimulate managerial performance improvement where performance measurements include various measurements such as financial performance, marketing performance, and production performance in the property industry. Research design, data, and methodology: Total sample are 105 respondents coming from middle to top level of management in the property sector in Indonesia. To empirically prove the results of this study using multiply regression analysis as a test tool for analysis. Results and Findings: The results of this study confirm that TQM has a positive effect on market competition, innovation, and company performance indirectly. However, it does not have a significant impact if it is directly related to TQM on company performance. In this case, TQM for property companies in Indonesia would not have been possible without the role of innovation and market competition. So that the managerial implications of this study also confirm that TQM is essential and feels obligatory to be implemented optimally.

• 국제물리치료학회지
• /
• 제9권4호
• /
• pp.1591-1595
• /
• 2018

The number of healthy older adults is rapidly increasing recently owing to the increase of the elderly population. Therefore, programs for improving the cognitive functions of these healthy seniors are actively being expanded. This study aimed to prevent the decline of cognitive function due to aging by applying a program enhancing cognitive functions to healthy older adults. The objective of this study was to evaluate the effects of Korean computer-based cognitive rehabilitation program (CoTras), which is commonly used in cognitive therapy for the aging, on the memory of the elderly. The subjects had scored at least 24 points in MMSE-K. CoTras was applied once a week (30 minutes) for one month. Electronic pegboard programs were used as an evaluation tool: order memory (difficulty=low) and location memory (difficulty=medium). The order and location memories were compared before and after the intervention. The Wilcoxon signed rank-sum test was used for the study at the significance level of ${\alpha}=.05$. The results showed that CoTras significantly improved order memory and location memory. Therefore, CoTras can be applied to the healthy elderly for improving that memory improvement training has a positive impact on healthy older adults result in the development of memory enhancement programs can be expanded in the future.

• Journal of Electrical Engineering and Technology
• /
• 제11권1호
• /
• pp.47-54
• /
• 2016

Microgrids offer several reliability benefits, such as the improvement of load-point reliability and the opportunity for reliability-differentiated services. The primary goal of this work is to investigate the impacts of operating condition on the reliability index for microgrid system. It relies on a component failure rate model which quantifies the relationship between component failure rate and state variables. Some parameters involved are characterized by subjective uncertainty. Thus, fuzzy numbers are introduced to represent such parameters, and an optimization model based on Fuzzy Chance Constrained Programming (FCCP) is established for reliability index calculation. In addition, we present a hybrid algorithm which combines scenario enumeration and fuzzy simulation as a solution tool. The simulations in a microgrid test system show that reliability indices without considering operating condition can often prove to be optimistic. We also investigate two groups of situations, which include the different penetration levels of microsource and different confidence levels. The results support the necessity of considering operating condition for achieving accurate reliability evaluation.

• 열처리공학회지
• /
• 제16권3호
• /
• pp.134-140
• /
• 2003

Effects of cryogenic treatment and tempering temperature on the amount of retained austenite, hardness and wear properties has been investigated using alloy tool steel, STD 11. Cryogenic treatments were performed at the temperatures of $-100^{\circ}C$, $-150^{\circ}C$ and $-196^{\circ}C$, and tempering were performed at $200^{\circ}C$ and $530^{\circ}C$. It was shown that lower hardness value was obtained on high temperature ($530^{\circ}C$) tempering even after cryogenic treatment. And retained austenite was not entirely transformed to martensite after cryogenic treatment even at $-196^{\circ}C$, which was not consistent with the belief that $-80^{\circ}C$ was sufficient to entirely transform any austenite retained in the quenched microstructure. Austenite retained in cryogenic treated condition was completely transformed to martensite only after tempering at $530^{\circ}C$. As far as wear test conditions in this investigation, it was found that cryogenic treatments improved the sliding wear resistance, but improvement of wear resistance was not directly related with retained austenite contents. And it was found that predominent wear mechanisms of STD 11 steel were oxidation wear and adhesive wear In sliding wear conditions.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제52권4호
• /
• pp.212-222
• /
• 2003

The ability to efficiently and robustly recover accurate 3D terrain models from sets of stereoscopic images is important to many civilian and military applications. A stereo matching has been an important tool for reconstructing three dimensional terrain. However, there exist many factors causing stereo matching error, such as occlusion, no feature or repetitive pattern in the correlation window, intensity variation, etc. Among them, occlusion can be only resolved by true multi-image stereo. In this paper, we present multi-image stereo method using DEM fusion as one of efficient and reliable true multi-image methods. Elevations generated by all pairs of images are combined by the fusion process which accepts an accurate elevation and rejects an outlier. We propose three fusion schemes: THD(Thresholding), BPS(Best Pair Selection) and MS(Median Selection). THD averages elevations after rejecting outliers by thresholding, while BPS selects the most reliable elevation. To determine the reliability of a elevation or detect the outlier, we employ the measure of self-consistency. The last scheme, MS, selects the median value of elevations. We test the effectiveness of the proposed methods with a quantitative analysis using simulated images. Experimental results indicate that all three fusion schemes showed much better improvement over the conventional binocular stereo in natural terrain of 29 Palms and urban site of Avenches.

• 한국경영과학회지
• /
• 제29권2호
• /
• pp.77-95
• /
• 2004

This paper deals with the process planning of flexible manufacturing systems (FMS) with various flexibilities and multiple objectives. The consideration of the manufacturing flexibility is crucial for the efficient utilization of FMS. The machine, tool, sequence, and process flexibilities are considered In this research. The flexibilities cause to increase the Problem complexity. To solve the process planning problem, an this paper an evolutionary algorithm is used as a methodology. The algorithm is named multiobjective competitive evolutionary algorithm (MOCEA), which is developed in this research. The feature of MOCEA is the incorporation of competitive coevolution in the existing multiobjective evolutionary algorithm. In MOCEA competitive coevolution plays a role to encourage population diversity. This results in the improvement of solution quality and, that is, leads to find diverse and good solutions. Good solutions means near or true Pareto optimal solutions. To verify the Performance of MOCEA, the extensive experiments are performed with various test-bed problems that have distinct levels of variations in the four kinds of flexibilities. The experiments reveal that MOCEA is a promising approach to the multiobjective process planning of FMS.