• International Journal of High-Rise Buildings
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• v.8 no.2
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• pp.107-116
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• 2019

The use of computational fluid dynamics (CFD) is becoming an increasingly popular means to model wind flows in and around buildings. The first published application of CFD to both indoor and outdoor building airflows was in the 1970's. Since then, CFD usage has expanded to include different aspects of building design. Wind tunnel testing (WTT) on buildings for wind loads goes back as far as 1908. Gustave Eiffel built a pair of wind tunnels in 1908 and 1912. Using these he published wind loads on an aircraft hangar in 1919 as cited in Hoerner (1965 - page 74). The second of these wind tunnels is still in use today for tests including building design ($Damljanovi{\acute{c}}$, 2012). The Empire State Building was tested in 1933 in smooth flow - see Baskaran (1993). The World Trade Center Twin Towers in New York City were wind tunnel tested in the mid-sixties for both wind loads, at Colorado State University (CSU) and the [US] National Physical Laboratory (NPL), as well as pedestrian level winds (PLW) at the University of Western Ontario (UWO) - Baskaran (1993). Since then, the understanding of the planetary boundary layer, recognition of the structures of turbulent wakes, instrumentation, methodologies and analysis have been continuously refined. There is a drive to replace WTT with computational methods, with the rationale that CFD is quicker, less expensive and gives more information and control to the architects. However, there is little information available to building owners and architects on the limitations of CFD for flows around buildings and communities. Hence building owners, developers, engineers and architects are not aware of the risks they incur by using CFD for different studies, traditionally conducted using wind tunnels. This paper will explain what needs to happen for CFD to replace wind tunnels. Ultimately, we anticipate the reader will come to the same conclusion that we have drawn: both WTT and CFD will continue to play important roles in building and infrastructure design. The most pressing challenge for the design and engineering community is to understand the strengths and limitations of each tool so that they can leverage and exploit the benefits that each offers while adhering to our moral and professional obligation to hold paramount the safety, health, and welfare of the public.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.3
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• pp.487-498
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• 2023

Security incidents using vulnerabilities in cloud services occur, but it is difficult to collect and analyze traces of incidents in cloud environments with complex and diverse service models. As a result, the importance of cloud forensics research has emerged, and infringement response scenarios must be designed from the perspective of cloud service users (CSUs) and cloud service providers (CSPs) based on representative security threat cases in the public cloud service model. This simulated hacking-based proactive cloud infringement response framework can be used to respond to the cloud service critical resource attack process from the viewpoint of vulnerability detection before cyberattacks occur on the cloud, and can also be expected for data acquisition. Therefore, in this paper, we propose a framework for preventive cloud infringement based on simulated hacking by analyzing and utilizing Cloudfox, a cloud penetration test tool.

• Journal of Korean Society for Quality Management
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• v.51 no.2
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• pp.315-327
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• 2023

Purpose: Recently, research has continued to predict the time of failure of the facility through measurement data obtained by attaching a sensor to the facility. However, depending on the facility, it may be difficult to attach a sensor. The purpose of this study is to propose a power generation maintenance plan system based on failure record data obtained from Continuous Ship Unloader, one of the facilities that is difficult to attach sensors. Methods: This study uses data collected from 2012 to 2022 from the 'CSU-1B' model among Continuous Ship Unloader operated by Korea Midland Power Co., LTD. By fitting fault record data to the Weibull distribution, appropriate maintenance cycles and ranges for each target facility subsystem are derived. In addition, maintenance group between subsystems is selected through Euclidean distance, a metric often used for time series data similarity. Through this, a system for establishing an maintenance plan for power generation facilities is proposed. Results: The results of this study are as follows. For the 17 subsystems of the Continuous Ship Unloader, proper maintenance cycles and ranges were determined, and a total of four maintenance groups were chosen. This resulted in the creation of an power generation maintenance plan system and the establishment of an maintenance plan. Conclusion: This study is a case study of power generation facilities. We proposed a maintenance plan system for Continuous Ship Unloader among power generation facilities.

• Archives of design research
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• v.15 no.4
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• pp.275-284
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• 2002

To improve the social and economic position of the disabled people and secure their human rights, an integrated society should be buill. To build such a society, an adequate access should be provided to the movement or in using buildings or facilities. The inconveniences from social life on the part of the disabled people might not result from their impairment or disability, but from physical and social barriers in the environment surrounding them. Therefore, it is necessary to reconstruct entire systems of the society as a disabled people-friendly structure in order to remove those barriers, make them stand their own feet in our communities and freely participate in the social activities. This will eventually lead to build a society in which all people including the disabled people can use those facilities in a more convenient way. It is almost impossible for the disabled people to safely and conveniently access to and use facilities and equipments and freely move to their desired places, without any help from others in Korea. Even though, there are currently many disabled people-related convenience facilities, they have been independently built without a connection with other facilities and buildings, thus not greatly useful. Even when convenience facilities have been built, mostly they are superficially set up; therefore, in many cases, the disabled peOple cannot use those facilities. In this. research, I tried a new concept of mobile wheelchair lift design, which the disabled people can operate without restrictions, when using the public facilities. The key to this research was to develop the existing import-oriented simple functional products to a new system with functional safety and high quality orientation. Also, this research aimed at bringing an. import substitution effect, as well as preempting the mobile wheelchair lift market by advancing into overseas markets through application of new image designs in the field of disabled people aid equipments.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.325-338
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• 2003

Video adaptation in response to dynamic resource conditions and user preferences is required as a key technology to enable universal multimedia access (UMA) through heterogeneous networks by a multitude of devices In a seamless way. Although many adaptation techniques exist, selections of appropriate adaptations among multiple choices that would satisfy given constraints are often ad hoc. To provide a systematic solution, we present a general conceptual framework to model video entity, adaptation, resource, utility, and relations among them. It allows for formulation of various adaptation problems as resource-constrained utility maximization. We apply the framework to a practical case of dynamic bit rate adaptation of MPEG-4 video streams by employing combination of frame dropping and DCT coefficient dropping. Furthermore, we present a descriptor, which has been accepted as a part of MPEG-21 Digital Item Adaptation (DIA), for supporting terminal and network quality of service (QoS) in an interoperable manner. Experiments are presented to demonstrate the feasibility of the presented framework using the descriptor.