• IE interfaces
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• v.15 no.4
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• pp.444-451
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• 2002

Recently, the interest in technology valuation is revived and increasing mainly due to the lack of suitability of the traditional valuation methods in explaining the market reaction to newly-emerging knowledge-oriented companies. Moreover, many firms are now gearing their efforts to the strategic use of technology asset such as technology licensing, transfer and commercialization. Firms are also trying to enhance their technological competitiveness by re-evaluating their technology level and thus identifying the strengths/weaknesses of their technology portfolio. To accomplish this objective, the development of an integrated evaluation system for technology assets is essential. This paper presents a technology valuation system developed for a steel manufacturing company in South Korea. The valuation framework is based on; (1) the multi-attribute evaluation of technological competitiveness using Analytic Hierarchical Process and; (2) the expected future benefit of the technology using four different methods of discounted cash flow estimation. The suggested framework will be easily applicable to various industries where technological competitiveness should be evaluated systematically.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.37.1-37.1
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• 2008

Space Science and Technology Laboratory at Kyung Hee University developed an 80cm Nasmyth telescope with the joint work of Space & Astronomy, Inc. It was set up at Muju county public astronomical observatory in Jeonlabuk-Do. Nasmyth focus system was selected for the telescope to use two focal points by a rotatable tertiary mirror. Focal ratios of the telescope are f10, f5 respectively. Support of the main mirror is made with Lasalle-system. This system uses 24-points in the back side of the mirror that are all resting on small counter-weights and side support is 10-points Boll link Flexible type with 2 Lasalle type. The mount is wheel & disk type Alt-Azimuth design using DC-servo motors. External high accuracy encoder has 47,600 sine-waves/rot. These encoders are used to make real-time corrections on all gearing errors.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.85-92
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• 1998

This present paper describes a mathematical model of profile shifted elliptical gears, and this model is based on the concepts of envelope theory and conjugate geometry between the blank and the straight-sided rack cutter. The geometric model of the rack cutter includes working regions generating involute curves and fillets for trocoidal curves, and furthermore the addendum modified coeff. is considered for avoiding undercutting. The addendum modified coeff. is changed linearly along with pitch curves and must be the same absolute value at both major semi-axis and minor semi-axis. If undercutting is at all pronounced, the undercut tooth not only are weakened in strength, but lose a small portion of the involute adjacent to the base circle, then this loss of involute may cause a serious reduction in the length of contact. A very effective method of avoiding undercutting is to use the so-called profile shifted gearing. Non-undercutting condition is examined with the change of eccentricity and addendum modified coeff. in elliptical gears and then the minimum number of tooth is proposed not to gernerate undercutting phenomenon.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.572-577
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• 1997

This present paper describes a mathematical model of profile elliptical gears, and this model is based on the concepts of envelop theory and conjugate geometry between the blank and the straight-sided rack cutter. The geometric model of the rack cutter includes working regions generating involute curves andd fillets for trocoidal curves, and furthermore the addendum modified coeff,is considered for avoiding undercutting. The addendum modified coeff, is changed linearly along with pitch curves and must be the must be the same absolute value at both major semi-axis and minor semi-axis. If undercutting is at all pronounced, the undercut tooth not only are weakened in strength, but lose a small portion of the involute adjacent to the base circle, then this loss of involute may ncause a serios reduction in the length of contact. A very effective method of avoiding undercutting is to use the so-called profile shifted gearing. Non-undercutting conditon is examined with the change of eccentricity and addendum modefied coeff. in elliptical gears and then the minimum number of tooth is proposed not to gernerate undercutting phenomenon.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1057-1067
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• 2010

Vibration and noise analysis as well as strength of gear teeth, gear profile design are considered in order to develop the multi-gear train devices of synchro system for the guns of a warship. A new approach to the critical speed calculation of practical industrial multi-mesh geared system is presented. A transfer matrix model based on Hibner's branch method is developed and the natural properties of the branched rotor system are calculated with using the ${\lambda}$-matrix formulation. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered, shows that, at theoperating speed, there are not the critical speed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.420-427
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• 2016

Diverse research on gearing systems have been made to resolve gear NVH problems for many decades, and transmission error (T.E.) has been identified as one of the main sources generating gear noises. While gear profiles and amounts of tooth modifications have influences on gear noise in the design aspect, it is found that bad manufacturing conditions such as burrs, bumps and damage, which result in improper gear operating conditions, produce gear noise with respect to manufacturing process. In this paper, T.E. measurement system was introduced to examine the gears damaged or improperly manufactured, while they are assembled, by comparing T.E. values and various gear conditions with theoretical ones. This T.E. measurement system, following grinding machining process, has been installed in a manufacturing line in 2014, and it results that the transmission rework to resolve manufacturing problems is not needed at the end of line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.270-275
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• 2008

The straight bevel gear for automobile part has been manufactured by the cold forging instead of the gear machining tool for the mass production. The application to CAD/CAM system has been necessary in order to develop the precision product quickly by forging through the minimization of trial and error and confirm the reproducibility. In the study, the straight bevel gear with the crown teeth has been modelled by the CAD/CAM system. The master gear after the gearing test has been machined after the modelling, NC data generation and verification. The die for forging and the jig for machining has been manufactured using the master gear.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.11
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• pp.213-221
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• 2021

The paper attempts to investigate the optimal capital structure of Vietnamese listed firms based on a structural approach. Using the data from around 70 companies in the Consumer Staples sector listed on the Vietnamese Stock Exchange during the period 2018-2020, this study finds that the optimal capital structure of examined companies has a wide range of diversification. This can be explained by the various types of actual products for each typical firm within the chosen sector. The result also confirms that a large proportion of researched firms were actually overleveraged, which is consistent with the trade-off hypothesis that firms wish to take tax advantages while using more debt, which creates the benefits from tax-shield. Furthermore, the research highlights the reversed correlation, which suggests that the lower the company's risk (the lower the sigma of the assets), the greater the optimal capital structure is suggested. Another interesting finding is that almost all consumer staples companies have a better optimal capital structure under the Leland and Toft (1996) model than under the Leland (1994) model. Furthermore, there is a strong correlation of optimal financial leverage ratio between years. In other words, the optimal debt levels of the latter year are strongly dependent on the gearing levels of the previous years.

• International Journal of Computer Science & Network Security
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• v.23 no.2
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• pp.193-198
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• 2023

The article focuses on the areas of education activities in using techniques for teaching and learning with information and communication technologies (ICTs), researching and analyzing the available ICTs, gearing the technologies to the specific psychological and pedagogical conditions, independently building and modeling ICTs, enlarging and developing their use in the learning environment. The visualization of scientific research has been determined to be part of the educational support for building students' ICT competence during teaching and learning and is essential to the methodology culture. There have been specified main tasks for pedagogy technologies (PTs) to develop the skills of adaptability to the global digital space in students, their effective database operation and using the data bases as necessary elements for learning and as part of professional training for research. We provided rationalization for implementing the latest ICTs into the Ukrainian universities' curricula, as well as creating modern methods for using the technologies in the learning / teaching process and scientific activities.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.2
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• pp.100-107
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• 2023

This study intends to present the UAM pilot qualifications and training and education systems based on the roadmap of technology for K-UAM operation system, which is being promoted for commercialization in 2025. There are currently about 250 eVTOL manufactures around the world, and they are gearing up to produce a variety of UAM aircrafts. In Korea, 35 companies including Hyundai Motor company, Korean Air, Lotte and SKT are accelerating the development of UAM aircrafts. UAM is being developed as a public goods concept centered on public transportation and urban aviation rather than private transportation. Therefore, the UAM pilot qualification and education and training system should be suitable for operations in densely populated areas and complex urban enviroments. In other words, in order to ensure safe UAM operations, the competencies and qualifications of UAM pilots should be clearly established.