• Journal of Multimedia Information System
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• v.8 no.2
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• pp.93-100
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• 2021

Under the time-varying temperature, the high-temperature radiation of forgings and the change of reflection characteristics of oxide skin on the surface of forgings lead to the difficulty of obtaining images to truly reflect the geometric characteristics of forgings. It is urgent to study the clear and reliable acquisition method of hot forging feature image under time-varying temperature to meet the requirements of visual measurement of hot geometric parameters of forgings. Based on this, this chapter first puts forward the quality evaluation method of forging feature image, which provides guarantee for the accurate evaluation of feature image quality. Furthermore, the factors that affect the image quality, such as the radiation characteristics of forgings and the photographic characteristics of cameras, are analyzed, and the imaging spectrum which can effectively suppress the radiation intensity of forgings is determined. Finally, aiming at the problem that the quality of image acquisition is difficult to guarantee due to the drastic change of radiation intensity of forgings under time-varying temperature, an image acquisition method based on minimum signal-to-noise ratio (SNR) based laser light intensity adaptation is proposed, which significantly improves the definition of feature light strips in forging images at high temperature, and finally realizes the clear acquisition of feature images of large-scale hot forging under time-varying temperature.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.403-408
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• 2021

Various surface colors are predicted and implemented using the interference color generated by controlling the thickness of nano-level diamond like carbon (DLC) thin film. Samples having thicknesses of up to 385 nm and various interference colors are prepared using a single crystal silicon (100) substrate with changing processing times at low temperature by plasma-enhanced chemical vapor deposition. The thickness, surface roughness, color, phases, and anti-scratch performance under each condition are analyzed using a scanning electron microscope, colorimeter, micro-Raman device, and scratch tester. Coating with the same uniformity as the surface roughness of the substrate is possible over the entire experimental thickness range, and more than five different colors are implemented at this time. The color matched with the color predicted by the model, assuming only the reflection mode of the thin film. All the DLC thin films show constant D/G peak fraction without significant change, and have anti-scratch values of about 19 N. The results indicate the possibility that nano-level DLC thin films with various interference colors can be applied to exterior materials of actual mobile devices.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.151-155
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• 2021

The article is based on a model, in the context of which there are two fundamental building blocks of basic library skills and skills in the use of information technology. The former are formed within the framework of educational programs for users of academic libraries, the latter are formed within the framework of initiatives such as the European Computer Driving License. Between the basic and the highest levels of the concept of "information literacy" there are seven heading skills and attributes, the repeated practice of which leads from the position of a competent user to an expert level of reflection and critical awareness of information as an intellectual resource. Freshmen will likely be at the beginning of the arrow, probably practicing only the first four skills, while graduate students and young scientists will be closer to the end and will use seven skills.

• Journal of Astronomy and Space Sciences
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• v.38 no.1
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• pp.45-53
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• 2021

GLONASS, a satellite navigation system developed in Russia since 1976, is defunct and orbits in an unstable attitude. The satellites in these problems are not managed and there is no precise information, which can increase the risk of collisions with other space objects. In this study, detailed attitude dynamic have to be analyzed through photometry data, which requires spin period and spin axis. The light curve data is obtained by observing through the photometer at the Graz station and the power spectrum is calculated to obtain the cycle of the satellite. The geometric relationship between observer and sun is analyzed for GLONASS-50 satellite. The box-wing model is applied to obtain the phase reflection of the satellite and obtain the Irradiation of the satellite through this information. In Light Curve and Irradiation, the spin axis is calculated for each peak points with the distance square minimum technique. The spin axis of the GLONASS-50 satellite is RA = 116°, Dec = 92°.

• Journal of Information Technology Services
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• v.21 no.1
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• pp.103-125
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• 2022

This study empirically examines the correlation between the data, system, service quality, collective intelligence, innovation activity, and work performance of the KMS for employees of state-run enterprises. This study also confirmed that collective intelligence and innovation activity have a mediating effect on the relationship between KMS system quality and work performance. For this study, employees of state-run enterprises completed a 5-point Likert scale survey, and the data obtained were analyzed with descriptive statistics. The reliability and validity of variables were also verified through a measurement model analysis. Structural equation modeling of IBM SPSS 26 and AMOS 26 were used to prove the hypothesis. Through this study, For the improvement of sustainable work performance of state-run enterprises, which is a difficult issue to solve, not only should the quality of the KMS utilized in the enterprises be improved and managed, but also the design for various incentive schemes tailored to the enterprises' job characteristics, such as rewards, HR bonus, work incentives, job allowance, and encouragement from the head of the enterprise, should be reviewed and continuously developed in reflection of the active collective intelligence of the employees and the effect of innovation activities. Then, the work performance of public institutions will increase.

• Current Optics and Photonics
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• v.6 no.1
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• pp.44-50
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• 2022

An off-axis zone plate is able to focus on a single order while neglecting the zeroth order in a visible imaging system. This allows one to enhance the contrast quality in diffractive images, which is the major advantage of this type of zone plate. However, most previous reflection zone plates are used in focusing X-rays with a small grazing incident angle and are intricately designed with the use of a local grating period. In this study, we suggest the design of an off-axis elliptical zone plate (EZP) that is used to focus a monochromatic light beam with separation between the first and unfocused orders under a large grazing incident angle of 45°. An assumption using the total grating period, which depends on the average and constant grating period, is proposed to calculate the desired distance between the first and zeroth order and to simplify the construction of a novel model off-center EZP. Four diffractive optical elements (DOEs) with different parameters were subsequently fabricated by direct laser lithography and then verified using a performance evaluation system to compare the results from the assumption with the experimental results.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.513-520
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• 2000

An integrated grader which measures soluble solid content, color and weight of fresh apples was developed by NAMRI. The prototype grader consists of the near infrared spectroscopy and machine vision system. Image processing system and an algorithm to evaluate color were developed to speed up the color evaluation of apples. To avoid the light glare and specular reflection, an half-spherical illumination chamber was designed and fabricated to detect the color images of spherical-shaped apples more precisely. A color revision model based on neural network was developed. Near-infrared(NIR) spectroscopy system using NIR reflectance method developed by Lee et al(1998) of NAMRI was used to evaluate soluble solid content. In order to observe the performance of the grader, tests were conducted on conditions that there are 3 classes in weight sorting, 4 classes in combination of color and soluble solid content, and thus 12 classes in combined sorting. The average accuracy in weight, color and soluble solid content is more than about 90 % with the capacity of 3 fruits per second.

• Journal of Korean Port Research
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• v.6 no.1
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• pp.69-91
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• 1992

A new type of horizontal submerged break water or fixed structure to control waves near coastal area is introduced to focus wave energy before or behind it. Intentionally, the water depth near the structure is changed gradually to get a refraction and diffraction effect. The concentration of wave energy due to the structure was analyzed for the selected design of structure. The shape of the submerged structure in consideration is a circular combined with elliptical curve not to cause reflection of waves at the extreme edge of the structure but cause wave scattering. The direction of the structure against the incident wave is changed easily in the model Applying a regular wave train the following were examined. 1) whether a crescent plain submerged structure designed by the wave refraction theory can concentrate wave energy at a focal zone behind and before it without wave breaking phenomenon. 2) Location of maximum wave amplification factor in terms of the incident wave direction, wave period, etc. In any event the study would contribute to control waves near coastal area and to protect a beach from erosion without interruption of ocean view it is an useful study for the concentration of wave energy efficiently with the increase of wave height.

• Human Ecology Research
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• v.62 no.1
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• pp.81-100
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• 2024

This paper presents a case study in which a lesson was designed and applied to enhance preservice home economics teachers' instructional design competence using the metaverse. For 15 weeks from March 6 to June 14, 14 students enrolled on the course 'Multimedia Home Economics Education' for preservice home economics teachers used the metaverse to engage in problem-based learning to solve instructional design problems in home economics classes. In accordance with the ADDIE design model, in the analysis stage, we assessed preservice home economics teachers' level of knowledge of lessons using the metaverse, and their perceptions of the possibility, necessity, and usefulness of using the metaverse in home economics lessons. In the design and development stage, lesson plans, questions for problem-based learning, assessment tools, and teaching and learning materials were developed. The implementation was conducted in parallel with training on understanding multimedia and the metaverse, and instructional design competence was evaluated through pre- and post-testing and reflection journals. The results revealed that the preservice home economics teachers acquired a good understanding of lessons using the metaverse, learned how to design lessons for self-directed learning by applying the metaverse to their home and classroom, and gained confidence in applying it to their teaching practice or in-service work. It is expected that the results of this study will be used as support materials for prospective and current home economics teachers to design home economics lessons using the metaverse, thereby expanding the horizons of home economics education.

• The Korean Journal of Financial Management
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• v.25 no.2
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• pp.1-31
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• 2008

Before the financial crisis in 1997, Korean bond markets had been those of corporate bonds with relatively high market yield. During the period, most of major institutional investors tend to utilize passive strategies such as buying and holding. After the crisis, however, they could not help choosing active bond management strategies because of lowed yield level and intensified competition among the financial institutions. This study is forced on the yield curve, which is the reflection of all information on the bond investment environments. The study also make analysis on the major economic and securities market factors and its structural relationship with the shape of the curve such as level, curvature and slope. For these purposes, an empirical model based on the Nelson-Siegel Model is estimated with the data during $1999{\sim}2006$. Out-of-sample forecasting is also made to test the usefulness of the estimated model. In addition, the dependent variables which are the estimates of level and slope are estimated on the macro variables and securities market variables. VAR and SUR models are used for the estimation. Estimation results show that level and slope of the yield curve are influenced by the target call rate change, exchange rate change rate, inflation rate. These results provide practical implications for the active managements in the overall treasury bond markets.