• Journal of Digital Convergence
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• v.11 no.9
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• pp.95-102
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• 2013

The purpose of this study is to explain why the social phenomenon of the wisdom of the crowd does not empirically apply. The motivation of this study is to explain the Korean social issue: the Tablo incident. In this study, 50 university students participated in the experiments to assess the impact of social media on the wisdom of crowds effect. We find evidence of a positive wisdom of crowds effect, when respondents are less exposed to media. In contrast, the collective information seems to be negatively distorted by respondents highly exposed to media. This research has strong implication for education policy and theories of social interaction.

• Journal of Ocean Engineering and Technology
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• v.26 no.5
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• pp.47-54
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• 2012

In this study, numerical simulations were performed to evaluate the current loads acting on the multi-legged underwater robot "Crabster" with a variety of incident angles using the ANSYS-CFX package. The Reynolds-averaged Navier-Stokes equations were solved to simulate the fluid flow around Crabster to calculate the forces and moments induced by incoming currents with various angles. First, to assess the posture stability of the body, the forces and moments were calculated with various incident angles when the current acted in the vertical and horizontal directions. Next, two forms of legs (box and foil types) were evaluated to determine the hydrodynamic force variation. Finally, the current forces and moments acting on the Crabster body with the legs attached were estimated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.3
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• pp.21-29
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• 2016

In this paper, optical tracking and analysis was carried out to find the optical properties with respect to various geometric design parameters of collimator lens which is very efficient when collect the light. As a result, a whole, ellipse incident part can obtain a high light efficiency and a narrow beam angle, and angled cylinder incident part is confirmed to obtain high efficiency and a narrow beam angle at a certain height or more. When Transmission part have a specific surface which can reflect the light in forward direction, a good optical properties was confirmed.

• Journal of Preventive Medicine and Public Health
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• v.52 no.1
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• pp.41-50
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• 2019

Objectives: The aim of this study was to investigate cancer patients' utilization of tertiary hospitals in Seoul before and after the benefit expansion policy implemented in 2013. Methods: This was a before-and-after study using claims data of the Korean National Health Insurance Service from 2011 to 2016. The unit of analysis was inpatient episodes, and inpatient episodes involving a malignant neoplasm (International Classification of Diseases, Tenth Revision codes: C00-C97) were included in this study. The total sample (n=5 565 076) was divided into incident cases and prevalent cases according to medical use due to cancer in prior years. The tertiary hospitals in Seoul were divided into two groups (the five largest hospitals and the other tertiary hospitals in Seoul). Results: The proportions of the incident and prevalent episodes occurring in tertiary hospitals in Seoul were 34.9% and 37.2%, respectively, of which more than 70% occurred in the five largest hospitals in Seoul. Utilization of tertiary hospitals in Seoul was higher for inpatient episodes involving cancer surgery, patients with a higher income, patients living in areas close to Seoul, and patients living in areas without a metropolitan city. The utilization of the five largest hospitals increased by 2 percentage points after the policy went into effect. Conclusions: The utilization of tertiary hospitals in Seoul was concentrated among the five largest hospitals. Future research is necessary to identify the consequences of this utilization pattern.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.835-836
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• 2014

In this paper, we have designed the collimator of different sizes structure for the development of stereo radiation detector. And we conducted a study of the optimal structure of collimator using the results of the Gamma-ray irradiation test associated with the change of the incident angle. According to the results of the performance analysis, and showed the results of the optimal incident angle 2. Results of the paper are used as basic data for designing the structure of the detector efficiency for radiation detection.

• Convergence Security Journal
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• v.19 no.1
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• pp.87-95
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• 2019

The damage is increasing due to many encroachment accidents caused by increasingly sophisticated cyber attacks. Many institutions and businesses lack early response to invest a lot of resources in the infrastructure for incident detection. The initial response of an intrusion is to identify the route of attack, and many cyber attacks are targeted at software vulnerabilities. Therefore, analyzing the artifacts of a Windows system against software vulnerabilities and classifying the analyzed data can be utilized for rapid initial response. Therefore, the remaining artifacts upon entry of attacks by software are classified, and artifact grouping is presented for use in analysis of encroachment accidents.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.104-115
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• 2019

Since the Fukushima Daiichi accident, there has been an emphasis on the risk resulting from multi-unit accidents. Human reliability analysis (HRA) is one of the important issues in multi-unit probabilistic safety assessment (MUPSA). Hence, there is a need to properly identify all the human and organizational factors relevant to a multi-unit incident scenario in a nuclear power plant (NPP). This study identifies and categorizes the human and organizational factors relevant to a multi-unit incident scenario of NPPs based on a review of relevant literature. These factors are then analyzed to ascertain all possible unit-to-unit interactions that need to be considered in the multi-unit HRA and the pattern of interactions. The human and organizational factors are classified into five categories: organization, work device, task, performance shaping factors, and environmental factors. The identification and classification of these factors will significantly contribute to the development of adequate strategies and guidelines for managing multi-unit accidents. This study is a necessary initial step in developing an effective HRA method for multiple NPP units in a site.

• Journal of Contemporary Eastern Asia
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• v.19 no.2
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• pp.148-168
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• 2020

In April, 2020, amid widespread fear of a second wave of infections of the novel coronavirus in China, local authorities in Guangzhou cracked down on the city's black population, resulting in mass evictions of Africans. The incident raises several questions about racism in China. How should we interpret this heavy-handed treatment of black people? Was this an isolated incident? What motivated such operations? In this article, I explain social control of Guangzhou's African communities as a problem of municipal politics. What underlies the government's heavy handed approach, I argue, are those communities' ties to rurality, which constitute a roadblock in the city's urban upgrade. Using Dengfeng Village, one of the best known African communities in China, as a case study, I show that efforts to upgrade the area by the local state and the real estate industry were frustrated by the community's status as an urban village. Africans, whom Chinese have historically associated with rurality, are seen as contributing to a space that has long been stigmatized as a spatial manifestation of rural people's lack of self-discipline. To better reveal the interconnection between social control and urban politics, I place official action in context of the history of the community's formation and the lived experience. This analysis of Dengfeng applies to various extents to other major African communities in Guangzhou.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.6
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• pp.237-246
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• 2022

Based on the random-vibration-theory methodology, dynamic responses of nuclear facilities subjected to obliquely incidental and incoherent earthquake ground motions are calculated. The spectral power density functions of the 6-degree-of-freedom motions of a rigid foundation due to the incoherent ground motions are obtained with the local wave scattering and wave passage effects taken into consideration. The spectral power density function for the pseudo-acceleration of equipment installed on a structural floor is derived. The spectral acceleration of the equipment or the in-structure response spectrum is then estimated using the peak factors of random vibration. The approach is applied to nuclear power plant structures installed on half-spaces, and the reduction of high-frequency earthquake responses due to obliquely incident incoherent earthquake ground motions is examined. The influences of local wave scattering and wave passage effects are investigated for three half-spaces with different shear-wave velocities. When the shear-wave velocity is sufficiently large like hard rock, the local wave scattering significantly affects the reduction of the earthquake responses. In the cases of rock or soft rock, the earthquake responses of structures are further affected by the incident angles of seismic waves or the wave passage effects.

• Wind and Structures
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• v.37 no.1
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• pp.1-13
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• 2023

Due to the irregular shape and the deviation of stiffness center and gravity center, buildings always suffer from complex surface load and vibration response under wind action. This study is dedicated to analyze the surface wind load and wind-induced response of an irregular building, and to discuss the possibility of top swimming pool as a TLD to diminish wind-induced vibration of the structure. Wind tunnel test was carried out on a hotel with irregular shape to analyze the wind load and structural response under 8 wind incident angles. Then a precise numerical model was established and calibrated through experimental results. The top swimming pool was designed according to the principle of frequency modulation, and equations of motion of the control system were derived theoretically. Finally, the wind induced response of the structure controlled by the pool was calculated numerically. The results show that both of wind loads and wind-induced responses of the structure are significantly different with wind incident angle varies, and the across-wind response is nonnegligible. The top swimming pool has acceptable damping effect, and can be designed as TLD to mitigate wind response.