• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.733-734
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• 2016

This study proposes a novel approach for ground segmentation of 3D point cloud. We combine two techniques: gradient threshold segmentation, and mean height evaluation. Acquired 3D point cloud is represented as a graph data structures by exploiting the structure of 2D reference image. The ground parts nearing the position of the sensor are segmented based on gradient threshold technique. For sparse regions, we separate the ground and nonground by using a technique called mean height evaluation. The main contribution of this study is a new ground segmentation algorithm which works well with 3D point clouds from various environments. The processing time is acceptable and it allows the algorithm running in real time.

• Korean Journal of Optics and Photonics
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• v.20 no.5
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• pp.288-293
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• 2009

Polarization characteristics of a composite film composed of two optically anisotropic films are analyzed. The procedure to determine the effective optics axis and the equivalent retardation of the composite film is suggested in conjuction with the related ellipsometric expressions. The explicit expressions of the effective optic axis and the equivalent retardation of a non-uniform anisotropic film are derived when all optic axes are parallel. Those expressions of the composite film where optic axes of two constituting anisotropic films are not parallel are also derived. Dependence of those expressions on the polarization state of the incident light or the azimuth angle of the linearly polarized light and their limit when applied to practical use are discussed.

• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.472-478
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• 2001

We determined the optical constants and thickness of organic electroluminescence thin films using variable angle spectroscopic ellipsometry. Using the measured transmittance spectra and the spectroscopic ellipsomeoy data of the organic films on glass substrates in the optically transparent region, we determined the effective thickness and the refractive indices of organic thin films. Then by applying a numerical inversion method to variable angle spectro-ellipsometry data, we determined the complex refractive index at each wavelength including the optically absorbing region, as well as the thickness and surface micro-roughness of the organic thin films. The calculated transmittance spectra showed a tight agreement with the measured ones, confining the validity of the present model analysis.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.503-510
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• 2002

In this paper, a general purpose embedded computer system is designed and implemented. The most crucial points of the system are extensibility and flexibility. The hardware of the developed system is composed of three modules and the software provides hardware independent application program interfaces. Moreover, uC/OS-II, a well-known open realtime kernel. is extended and ported onto the system. The extended uC/OS-II supports that multiple processes can have the same priority and such processes are scheduled in a round-robin manner.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.2
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• pp.177-186
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• 2022

A network QoS model for the joint integrated C4I structure was proposed for the integration of network infrastructure and network operations(NetOps) for NCOE. Detailed QoS requirements process of the joint integrated C4I systems are needs in the Multi-Domain Operation Environment(MDOE). A process is proposed for identifying QoS requirements and establishing in the MDOE using JMT(Joint Mission Thread) reference architecture and solution architecture. Mission analysis identify JCOAs(Joint Critical Operational Activities) and related activities based on JMT & System architecture's OVs, and Information analysis identify QoS attributes using System architecture's SVs. Identifying QoS attributes will be registered at PPS Registry by pre-regulated process, and will be set-up by NetOps. MDOE QoS requirement Process will support efficiently MUM-T and smart defense platform users under the future uncertain battlefield circumstances.

• Journal of the Korean Regional Science Association
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• v.38 no.3
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• pp.41-49
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• 2022

This paper aimed at understanding the effect of infectious disease conditions on willingness to pay for the green roof implemented to reduce the urban heat island. For this purpose, the willingness to pay for the green roof under infectious disease and non-infectious disease conditions was calculated and comparatively analyzed using the contingent valuation method. As a result, there was a statistically significant difference in the willingness to pay according to the infectious disease condition, and it was confirmed that the willingness to pay for the infectious disease condition was lower than the non-infectious disease condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6504-6513
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• 2013

The result can be summarized as follows. First, the following periodically changing characteristics were examined:roof form(gambrel/hipped-flat-gable), structure of roof and wall(wood-framed-cement masonry-RC-Light iron framed), roof material(thatched-tiled-slate-cement/steel sheet-asphalt/sandwich panel/mortar water-proofing), wall material(clay plaster/lime plastered-dressing tile/bricks-painting on the cement plastering-native stone dressing/siding/tile), fence material(masonry of stone and cement bricks), and courtyard materials(clay and concrete). Secondly, the regionally changing characteristics of those elements, rural housing structure, roof form, roof structure material, wall finishing material, fence and courtyard material in the outer space, differed according to the location of rural housing, i.e.north, middle, south region. The changing characteristics of both the roof structure and wall structure are similar to those of the three regions.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.241-248
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• 2009

We suggest a new method to determine the off-alignment error of the composite film, together with in-plane($R_{in}$) and out-of-plane retardation($R_{th}$) of the compensation film, simultaneously. The composite film consists of a polarizing film and a compensation film for improvement of viewing angle of a liquid crystal display. We regarded the compensation film as o-plate with its optic axis along an arbitrary direction. By using an extended Jones matrix method, the polarization characteristics of the composite film are examined. The calculated Fourier constants, ($\alpha$, $\beta$) curves of the composite film as the azimuth angle is varied at the incident angles of $0^{\circ}$ and $50^{\circ}$, respectively, are used to determine the axis misalignment, the tilt angle and the azimuth angle of the compensation film by adopting the linear regressional analysis technique. Since this method can be applied for the inspection of the composite film even after laminating the polarizing film and the compensation film, it will be useful for simplifying the manufacturing process and reducing the production cost of liquid crystal display panels.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.123-135
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• 2020

This study examined how the quality of Netflix service affects user satisfaction and continuance intention. This study classified the quality of Netflix service as content diversity, rate system appropriateness, recommendation system, N-screen service, binge viewing, and service quality, and examined the effect of each dimension on user satisfaction and continuous intention. We conduced an online survey on 202 Netflix users and analyzed the data with the SEM. Results are as follows. First, content diversity, recommendation system, binge-viewing and service quality are positively associated with user satisfaction. Second, the N-Screen service has neither direct nor indirect effects on continuance intention. However, rate system has a direct effect on continuance intention. On the other hand, content diversity, recommendation systems, binge-viewing, and quality of service affect continuance intention positively through user satisfaction. Finally, it is shown that user satisfaction and continuance intention have a significant static correlation as predicted.

• Health Policy and Management
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• v.32 no.3
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• pp.293-303
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• 2022

Background: Coronavirus disease 2019 (COVID-19), which has occurred since the end of 2019, has caused tremendous damage not only in terms of disease and death but also in terms of economy. Accordingly, governments implemented health and quarantine policies to prevent the transmission and spread of COVID-19 and minimize economic effects, and implemented various countermeasures to reduce social and economic damage. However, the damage varies from country to country, and there are differences in the response of each government. Methods: Using 2020 data from the Organization for Economic Cooperation and Development countries, the effectiveness of governments' quarantine and economic policies in response to COVID-19 was calculated, and what factors determine the effectiveness were analyzed. While most of the previous studies analyzed the relationship between the government's quarantine policy and corona transmission and death, this study is characterized by considering the economic aspect in addition. Results: As a result of the analysis, the following results were obtained. First, when economic aspects are not considered, Asian and European countries have similar levels of efficiency, but when economic aspects are taken into account, Asian countries have higher efficiency. Second, population density had a negative effect on the efficiency of each country's policy, and long-term orientation was found to have an important impact when considering the economic aspect. Conclusion: We found that the governance index is an important variable influencing the efficiency, which shows that the effectiveness of government policies in response to the coronavirus depends heavily on the trust relationship between the government and the people.