• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.217-223
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• 2015

In this paper, the performance of a system was analyzed according to the design parameters of a LED secondary lens that can be applied at a very close range, e.g., for direct lighting or display systems. We designed the secondary lens of the very-close-range LED using an aspheric equation and analyzed its performance-particularly the angle of the beam spread, central luminous intensity, and light uniformity-with respect to the thickness of lens, radius, conic constant, and asphericity (4th). Our analysis shows that four parameters affect the performance. The simulation results indicate an optimal thickness of 1 mm and show that a larger radius yields higher performance. The optimal range for the conic constant was determined as -1.21 to -1.25, the optimal range for the asphericity was determined as 0.0047xx to 0.0049xx (4th).

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.3
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• pp.328-336
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• 2017

The exit surface of a lens is designed using a three-dimensional free-form expression in order to easily modify a curved surface. This enables the design of numerical values and mathematical things using three-dimensional free-form expression, and enhances precision because it can be fine-tuned via numerical control. The standard of "Classification of Luminaire Light Distribution" for outdoor lighting fixtures by IESNA is adopted in order to examine the correlation between three-dimensional free-form surface expression and lighting performance. The variation of light distribution type and range is analyzed using the values of maximum light intensity and 50% light intensity. The actual tolerance occurs owing to parameters such as the thickness of the lens, the distance between LEDs, and the movement of the center of the incident surface; the effects of changes in these parameters on the performance are compared and analyzed.

• Journal of Korea Game Society
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• v.18 no.4
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• pp.5-14
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• 2018

Nowadays, game development of new genres continues through convergence among existing genres, and the games of this hybrid-genre are gaining popularity around the world. Following this trend, it is meaningful to analyze the characteristic contents of the existing genre for more effective genre fusion. In this paper, in the genre of survival game, a genre of digital game, we would like to select a representative survival game for analysis of survival content, which is a key goal and core of the game, to identify common and differentiated features. For this purpose, we have studied game mechanics and game dynamic components around the contents of the survival game, based on the MDA framework.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.651-659
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• 2009

There are a great number of man-made and natural slopes in many parts of the world including Hong Kong and Mainland China. For example, there are over 40,000 slopes in Hong Kong registered by the Hong Kong Government. Landslides due to slope failures can often cause catastrophes that involve the loss of both lives and important facilities. GPS has been demonstrated to have great potentials for use in monitoring slope stability and landslides. However, the high hardware cost of GPS has limited the wide spread use of GPS for such applications. The multi-antenna GPS technology initiated by the research group and our collaborators has significantly reduced the cost of GPS and provided a solution to a number of associated problems such as data management and power supply. This paper discusses practical applications of multi-antenna GPS technology in slope monitoring, including system design, setting up, data transmission and management, and data quality analysis and control. Some slope monitoring examples are given to illustrate the points discussed.

• International Journal of High-Rise Buildings
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• v.1 no.4
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• pp.283-300
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• 2012

Wind-induced vibrations of buildings can be perceived when movement of objects caused by the vibration is seen. However, movement of objects that would normally be expected to trigger visual perception of building vibrations is not necessarily seen in actual building environments. Therefore, to evaluate habitability to building vibrations, it is necessary to examine the influence of movement of objects on vibration perception taking into account probability of seeing the objects. As the first step in this study, those data necessary to estimate probability of vibration perception from seeing of swaying objects have been measured during normal activities in actual buildings. In addition, statistical analysis of the data has also been carried out. As the second step in this study, the probability distribution of vibration perception by visual sensation is estimated using the series of data measured in the first step. Probability of seeing object is considered in the estimated probability distribution.

• Computers and Concrete
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• v.13 no.6
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• pp.799-827
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• 2014

In this paper, a theoretical and experimental study of the sectional behaviour of reinforced concrete beams subjected to short-term loads is carried out. The pure bending behaviour is analysed with moment-curvature diagrams. Thus, the experimental results obtained from 24 beams tested by the authors and reported in literature are compared with theoretical results obtained from a layered model, which combines the material parameters defined in Model Code 2010 with some of the most recognized tensions-tiffening models. Although the tests were carried out for short-term loads, the analysis demonstrates that rheological effects can be important and must be accounted to understand the experimental results. Another important conclusion for the beams tested in this work is that the method proposed by EC-2 tends to underestimate the tension-stiffening effects, leading to inaccuracies in the estimations of deflections. Thus, the actual formulation is analysed and a simple modification is proposed. The idea is the separation of the deflection prediction in two parts: one for short-term loads and other for rheological effects (shrinkage). The results obtained are in fairly good agreement with the experimental results, showing the feasibility of the proposed modification.

• Advances in aircraft and spacecraft science
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• v.2 no.3
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• pp.345-365
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• 2015

This paper focuses on the design, fabrication, testing and analysis of a novel load-bearing element with energy dissipation capability. A single element comprises two von-Mises trusses (VMTs), which are sandwiched between two plates and connected to dashpots that stroke as the VMTs cycle between stable equilibrium states. The elements can be assembled in-plane to form a large plate-like structure or stacked with different properties in each layer for improved load-adaptability. Also introduced in the elements are pre-loaded springs (PLSs) that provide high initial stiffness and allow the element to carry a static load even when the VMTs cannot under harmonic disturbance input. Simulations of the system behavior using the Simscape environment show good overall correlation with test data. Good energy dissipation capability is observed over a frequency range from 0.1 Hz to 2 Hz. The test and simulation results show that a two layer prototype, having one soft VMT layer and one stiff VMT layer, can provide good energy dissipation over a decade of variation in harmonic load amplitude, while retaining the ability to carry static load due to the PLSs. The paper discusses how system design parameter changes affect the static load capability and the hysteresis behavior.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.137-141
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• 2006

The purpose of GPS structural vibration monitoring is to obtain information on the frequency and amplitude of vibrations based on GPS observations that are often affected by various errors. Filters are frequently used to improve GPS accuracy and to retrieve vibration signals from GPS observational series. This paper studies the performances of four commonly used filters, i.e., Vondrak, wavelet, adaptive FIR and Kalman filters, for such applications. Controlled experiments are carried out and the results show that the capability of GPS in tracking structural dynamics and complex signals can be improved with any of the filters. The performances of Vondrak and wavelet filters are almost the same and superior to the adaptive FIR and Kalman filters. Recommendations are given for the selection of filters and filter parameters for different situations based on an analysis of the advantages and disadvantages of each of the filters.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.89-96
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• 2015

The study was conducted with statical analysis of data (828 data in 2010, 752 data in 2012, 648 data in 2014) in order to evaluate laboratory awareness difference of research employees working in different types of universities. Results of the study were as follows: First, university institutes in the order of polytechnic colleges, university, and junior college showed the highest laboratory safety awareness in 'awareness and education of laboratorial safety regulation' and 'awareness in laboratory risk factors'. Second, the difference in safety awareness of universities by year(years that conducted current status survey) was the highest in year 2014, then in 2010, and in 2008. Third, the difference of research employees working for laboratory safety management by year(years that conducted current status) showed that university had the highest laboratory safety awareness in year 2010, but it changed to polytechnic colleges in year 2012 and 2014. Through this study, we could recognize the difference in safety awareness of research employees working in university institutes.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.12
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• pp.509-518
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• 2021

Amid the Covid pandemic surge last year, customers and businesses started embracing digital transactions. Digital banking, as an answer to the cash-less-contact-less way of doing financial transactions, was highly convenient during the pandemic, especially in the Philippines. This position examines the Gen Y and Gen Z in the Philippine case and its willingness to encourage digitalization of the financial sector. This study aimed at evaluating the intention to use digital banking services using the factors (1) ease of use; (2) perceived usefulness; (3) perceived risk; (4) trust; (5) convenience. A total of 226 respondents were selected by random sampling method and linear regression was used to analyse the collected data. Analysis of the results show that the components (1) perceived ease of use; (2) perceived usefulness; (3) perceived risk; (4) trust; (5) convenience had a significant effect on intention to use digital banking while the demographics - gender, age, monthly income, and educational attainment do not have any significance on the intention to use digital banking. The relevance of the study can be used for marketing and financial strategies to increase the intention to use digital banking and to contribute to the enhancement of technology acceptance concerning digital banking.