• Structural Engineering and Mechanics
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• v.85 no.1
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• pp.135-145
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• 2023

This study presents the free vibrational responses of bi-directional axially graded cylindrical shell panels using 3D graded finite element approximation under a temperature field. The cylindrical shell panel is graded in two directions and made of metal-ceramic materials. To extract material properties, the Voigt model is combined with a Power-law material distribution. Convergence and validation studies are performed on the developed computational model to ensure its accuracy and effectiveness. Furthermore, a parametric study is performed to evaluate the developed model, which demonstrates that geometrical parameters, imperfect materials (porosity), support conditions, and surface temperature all have a significant impact on the free vibration responses of a bi-directional axially graded cylindrical shell panel in a thermal environment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.1
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• pp.22-30
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• 2004

As an information-oriented society comes, many people use PC and depend on database that network server has. However, the online data can be missed when a blackout happens and also a power failure effects on standard of judgment on Power Quality. Thus, it is reason of a trend using interruption-free live-line work when a trouble happens to power system. However, the 83％ among the number of people who receive an electric shock experience when a laborer is doing interruption-free live-line works. In interruption-free method, the education and the training problem has been issued. However, we have a few instructors for that training. Furthermore, the trainees have short training period, just 4 weeks. In this paper, to develope the method that has no restriction of a time and place and reduce the wasteful materials, immersion type virtual reality(or environment) technology is used. The users of a 3D immersion type VR training system can interact with the system by doing same action in the real safe environment. Thus, it can be valuable to apply this training system to a dangerous work like as "Interruption-free live-line work exchanging COS(Cut-Out-Switch)". In this program, the user works with a instruction on the window and speaker and can't work other tasks until each part of the task completed. The workers using this system can use their hands and viewpoint movement as he is in a real environment but the trainee can't use all parts and senses of a real body with the current VR technology. Despite of this weak point, when we consider the trends of improvement in electrical devices and communication technology, we can say that 3D graphic VR application has a high potentiality.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.4
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• pp.30-37
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• 2014

The Electronic Toll Collection System based on Free-Flow Multi-Lane is needed to solve some yearly problems such as traffic congestion, safety accident, maintenance by hold-up of one way hi-pass system. The hi-pass communication system is first-in, first-out method in one way environment so, it can't handle various running patterns such as vehicle platoon, switching lane and passing in multi-lane environment. In this thesis we compared and analyzed the communication system of foreign countries ETCS operating system and domestic hi-pass communication system, then studied communication system which can run in multiple-way accepting existing hi-pass OBU. And we formed the communication system of Free-Flow Multi-Lane environment as a plan using incoherent of IR antenna and coherent of RF antenna. The communication system in Free-Flow Multi-Lane environment can be used not alone in parking garages but in expressways of ETCS and toll roads from now on.

• Journal of Soil and Groundwater Environment
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• v.17 no.3
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• pp.32-38
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• 2012

This study was conducted to evaluate the slurping process affecting the variation of free product and VOCs concentration and the bioaugmentation effect on bioremediation process. Free products and soil gas were extracted from 30 extraction wells installed in a petroleum contaminated area. The extraction system was operated for 10 hours per day with 1 hour on-and-off mode. The thickness of free product in extraction well was decreased from 11.7 cm to 4.5 cm and the VOCs concentration was increased from 10.37 ppm to 30.78 ppm during the operation period. After the slurping process for 2 months, contaminated soil was treated with bioremediation process in 2 cells, $15{\times}40$ m, biologically enhanced with adjusting oxygen, moisture and nutrients concentration. Total 1,400 L of microbial inoculant, Naturesys. (Dong Myung Ent. Co.) was added to the pile B, which has an outstanding ability for degrading petroleum hydrocarbons. The results showed that bioremediaton effect in soil with the microorganisms solution is 33% higher than that in soil with only residual bacteria.

• Structural Engineering and Mechanics
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• v.85 no.4
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• pp.445-459
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• 2023

The current investigation is the first endeavor to apply the full layerwise finite element method (FEM) in free vibration analysis of functionally graded (FG) composite plates reinforced with graphene nanoplatelets (GPLs) in thermal environment. Unlike the equivalent single-layer (ESL) theories, the layerwise FEM focuses on all three-dimensional (3D) effects. The GPLs weight fraction is presumed invariable in each layer but varies through the plate thickness in a layerwise model. The modified Halpin-Tsai model is employed to acquire the effective Young's modulus. The rule of mixtures is applied to specify the effective Poisson's ratio and mass density. First, the current method is validated by comparing the numerical results with those stated in the available works. Next, a thorough numerical study is performed to examine the influence of various factors involving the pattern of distribution, weight fraction, geometry, and size of GPLs, together with the thickness-to-span ratio, thermal environment, and boundary conditions of the plate, on its free vibration behaviors. Numerical results demonstrate that employing a small percentage of GPL as reinforcement considerably grows the natural frequencies of the pure epoxy. Also, distributing more square-shaped GPLs, involving a smaller amount of graphene layers, and vicinity to the upper and lower surfaces make it the most efficient method to enhance the free vibration behaviors of the plate.

• The Journal of Sustainable Design and Educational Environment Research
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• v.16 no.3
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• pp.9-17
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• 2017

This study investigates and analyzes the convenience facilities to strengthen or mitigate the Barrier Free awareness and Kindergarten Barrier Free for the kindergarten school staff and the public facility officials of the education office. In addition, to improve the Barrier Free, the improvement facilities of the kindergarten were investigated and analyzed. First, from the institutional viewpoint, it is necessary to amend the existing regulations of the Act for the Promotion of the Convenience Promotion of Disabled Persons, Elderly and Pregnant Women in Korea, and to change the facilities for duties and recommended installation of the kindergarten and the Barrier Free certification standards. Second, in order to apply the Barrier Free certification system to the kindergarten in terms of facility environment, it is necessary to activate the barrier kind of the kindergarten so as to receive the Barrier Free certification by lowering the score of the items difficult to improve due to the terrain or building structure. Third, the perception of Barrier Free is still not high in terms of social awareness. The purpose of this study is to investigate the method of creating a Barrier Free for a kindergarten in the education and living space of children who are the socially underprivileged. Therefore, based on this study, it is anticipated that it will be an opportunity to promote change of Barrier Free in Kindergarten if an attempt is made to improve the Barrier Free certification index suitable for public kindergarten.

• The Journal of Sustainable Design and Educational Environment Research
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• v.18 no.1
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• pp.17-26
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• 2019

Barrier-free design reflects the attention of the disadvantaged groups. As a populous country with the largest population and the largest number of elderly people, China has made great progress in the field of the Barrier-free. The scope of this thesis is from the 1980s to 2012 in China, studying the development process of China's barrier-free design standards by comparing the two barrier-free design standards implemented in the history of such design. In this paper, the two standards are compared and analyzed in the following aspects, which are the numbering, chapters, scope of application, applicable objects and purposes, and so on. Compared with the 2001 barrier-free design standards, the 2012 one can be concluded that the development of barrier-free design in China has been accelerated, the scope of application has been widened than before, the content has been supplemented, and restrictions on terms have been reduced.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.265-276
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• 2019

The purpose of this study was to explore the possibility of creating barrier-free exhibition-appreciation environment based on the visually impaired person's perspectives. Participants were selected by the purposeful sampling method. Researchers conducted a couple of in-depth interviews with four visually impaired persons. Yin's case study method was employed to analyze qualitative information. The analysis revealed nine sub-themes in two sections: three from 'accessibility within the exhibition room'; and six from 'demand for immersive exhibition environment.' Based on the results, following suggestions were presented: First, we need to provide quality information appropriate for artworks-appreciation; secondly, to ensure the visually impaired people to appreciate the culture and arts without any barrier, we need to extend certification of barrier-free living environment to exhibition-appreciation area. Finally, to facilitate these two tasks we need to encourage the convergence research among science and technology, humanities and society, and culture and arts.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1004-1008
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• 1990

This research focuses on developing a new and computationally efficient algorithm for free space structuring and planning collision free paths for an autonomous mobile robot working in an environment populated with polygonal obstacles. The algorithm constructs the available free space between obstacles in terms of free convex area. A collision free path can be efficiently generated based on a graph constructed using the midpoints of common free links between free convex area as passing points. These points correspond to nodes in a graph and the connection between them within each convex area as arcs in this graph. The complexity of the search for collision free path is greatly reduced by minimizing the size of the graph to be searched concerning the number of nodes and the number of arcs connecting them. The analysis of the proposed algorithm shows its efficiency in terms of computation ability, safety and optimality.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.578-585
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• 2020

A new free-living marine nematode species of the genus Belbolla Andrássy, 1973 belonging to the family Enchelidiidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Belbolla wonkimi sp. nov. differs from its congeners by the combination of the following characteristics: a relatively long body (3263-3396 ㎛), the absence of ocelli, nine oesophageal bulbs in the posterior pharynx, well-developed two winged precloacal supplements, longer spicule length(115-130㎛, 1.6-1.8 anal body diameter long), and a triangle-shaped shorter gubernacular apophysis (17-18 ㎛). Comparative tables on the biogeographical and morphological characteristics of Belbolla species are presented. A DIC (differential interference contrast) photomicrograph of the new species is also provided. This is the first taxonomic report on the genus Belbolla from Korean waters.