• KIEAE Journal
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• 제1권2호
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• pp.47-54
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• 2001

Single sound absorbers such as porous materials, panels, and Helmholts resonators have limited performance with some extents of frequency region. For example, porous materials do not attenuate low frequency sounds, while panels do not absorb high frequency sounds. Composite absorption structure with coverings, porous materials, and air gaps are an alternative for wide band sound absorption. Slits, panels, perforated panels are those materials for coverings, glass wool, mineral wool, polyester, and polyurethane are frequently used porous materials. Air gap between the porous material and background surface is one of major factors which governs the absorption characteristics of composite absorption structures, especially in the low frequency area. Calculations and measurements show that the absorption coefficients of composite absorption structure, in mid and low frequency bands, are getting higher with increased air gaps. Perforated panels rather than slits and panels are good coverings with higher number as far as absorption coefficient is concerned. Perforated panels with porous materials and 37 cm of air gaps in background have high absorption coefficients for all frequency bands, above 0.7 to 1.0. All measurements are performed in reverberation chamber, Mokpo National University, according to ISO 354 and ISO 3382.

• Wind and Structures
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• 제22권3호
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• pp.307-328
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• 2016

This paper describes an investigation of the net wind loads on solar panels and wind loads on the underlying roof surface for panels mounted parallel to pitched roofs of domestic buildings. Typical solar panel array configurations were studied in a wind tunnel and the aerodynamic shape factors on the panels were put in a form appropriate for the Australian/New Zealand Wind Actions Standard AS/NZS 1170.2:2011. The results can also be used to obtain more refined design data on individual panels within an array. They also suggest values for the aerodynamic shape factors on the roof surface under the panels, based on a gust wind speed at roof height, of ${\pm}0.5$ for wind blowing parallel to the ridge, and ${\pm}0.6$ for wind blowing perpendicular to the ridge. The net loads on solar arrays in the middle portion of the roof are larger than those on the same portion of the roof without any solar panels, thus resulting in increased loads on the underlying roof structure.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.154-155
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• 2016

Although there is an increase in demand for free-form buildings, there are several problems such as increased cost and duration and decreased constructability arising from difficult member production and installation. To solve these problems, a technology to produce free-form panels using CNC machine was developed. According to the technology, the information on free-form buildings designed is delivered to the CNC machine, a form is shaped using the delivered information and free-form concrete panels are produced using the form. The limited construction site, duration and project cost as well as interferences with other work types should be considered upon in-situ production of free-form concrete panels. Thus, the purpose of this study is to conduct a base study on in-situ production layout of free-form concrete panels by system dynamics. With this study, we will discover the causal relationship of influence factors on in-situ production of free-form concrete panels, and improved productivity is expected through the production layout.

• 한국멀티미디어학회논문지
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• 제24권2호
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• pp.222-232
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• 2021

The power output of solar panels highly depends on environmental situations like weather and air pollution. Due to bad weather or air pollution, it is difficult for solar panels to operate at their full potential. Knowing the power output of solar panels in advance helps set up the solar panels correctly and work their possible potential. This paper presents an approach to predict the power output of solar panels based on weather and air pollution features using machine learning methods. We create machine learning models with three kinds set of features, such as weather, air pollution, and weather and air pollution. Our datasets are collected from the area of Seoul, South Korea, between 2017 and 2019. The experimental results show that the weather and air pollution features can be efficient factors to predict the power output of solar panels.

• 수완나부미
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• 제2권1호
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• pp.17-53
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• 2010

The Chandi Borobudur was likely constructed around 800 AD, during the period of the Sailendra dynasty in central Java, Indonesia. The Chandi Borobudur have 1460 narrative panels of reliefs which are distributed from the hidden foot to the fourth gallery. The 160 panels show various scenes of actions producing the corresponding results according to the Karmavibhanga(分別善惡報應經) text. Blameworthy activities with their purgatorial punishments and praiseworthy activities with their subsequent rewards are both shown. The 120 panels depict the biography of Buddha according to the Lalitavistara (方廣大莊嚴經) text. The 620 panels depict stories from Jatakas (本生譚) and Avadanas (譬喩經). The stories of 560 panels are based on Mahayayana (入法界品, 488 panels) and Bhadrucari (普賢行願讚, 72 panels) of Gandavyuha (華嚴經) text. In this study, among the 120 narrative reliefs which tell the life story of Buddha according to the Lalitavistara text in Chandi Borobudur, the images of Birth of Siddhārtha(誕生), The Great Departure (出家), Attaintment of Enlightenment (成道) and The First Sermon (初轉法輪) have been compared with the images of biography of Buddha showing in Ancient India, Gandhara and South India, and China. From a historical perspective of cultural exchange, Borobudur is very important site because it is located on the south route of transmission of Buddhism from India to South Asia, China, Korea and Japan. Study on the reliefs sculptured on the wall of Chandi Borobudur provide us information to understand the process of spreading and changes in styles of Buddhist arts.

• 소음진동
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• 제7권6호
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• pp.945-952
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• 1997

This paper shows the feasibility of the suggestion that the angle distribution of incident sound to panels might be gaussian, instead of the conventional uniform distribution in the analysis of transmission loss of panels. To prove the suggestion, the problems with the diffuse sound field in a reverberation room are examined by case studies and the comparision of the prediction with the measurement of sound transmission loss of walls are performed. The results of the comparision show good agreement between the two values.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.32-38
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• 1998

In order to investigate the relationship between the stiffness and structure of the automotive roof panels, two kinds of glass fiber reinforced plastic(GFRP) roof panels without and with insert material were fabricated by resin transfer molding(RTM) method. The stiffness test was performed at the same condition as it of actual driving. The structural design and material selection for improving the recyclability of GFRP roof panels were also covered.

• 대한기계학회논문집A
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• 제20권10호
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• pp.3199-3210
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• 1996

The buckling and postbuckling behaviors were sutdied analytically and experimentally for stiffened laminated composite panels under compression loading. The panels with I-, blade, -and hat-shapeed stiffeners were investigated. In the analysis, the stiffened panels were anlyzed using the nonlinear finite element method combined with an improved arc-length method. The progressive failure analysis was done by adopting the maximum stress criterion and complete unloading failure model. The effects of the fiber angles were investigated on the buckling and postbuckling behaviors. In the experiment, the web and the lower cap of each stiffener were formed by the continuous lay-up of the skin for cocuring the stiffened panels. Therefore, the separation between stiffener and skin was not found in the junction part even after postbuckling ultimate load and the stiffened panels had excellent postbuckling load carrying capacity. A shadow moire thchnique was used to monitor the out-of-plane deformations of the panels. The piezoelectric films were attached to the panels to get the failure characteristics of the panel. The analytical results on the buckling load, postbuckling ultimate load, and failure pattern showed good agreement with the experimental results.

• Computers and Concrete
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• 제10권1호
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• pp.1-18
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• 2012

This paper presents the details of studies conducted on hollow concrete block masonry (HCBM) units and wall panels. This study includes, compressive strength of unit block, ungrouted and grouted HCB prisms, flexural strength evaluation, testing of HCBM panels with and without opening. Non-linear finite element (FE) analysis of HCBM panels with and without opening has been carried out by simulating the actual test conditions. Constant vertical load is applied on the top of the wall panel and then lateral load is applied in incremental manner. The in-plane deformation is recorded under each incremental lateral load. Displacement ductility factors and response reduction factors have been evaluated based on experimental results. From the study, it is observed that fully grouted and partially reinforced HCBM panel without opening performed well compared to other types of wall panels in lateral load resistance and displacement ductility. In all the wall panels, shear cracks originated at loading point and moved towards the compression toe of the wall. The force reduction factor of a wall panel with opening is much less when compared with fully reinforced wall panel with no opening. The displacement values obtained by non-linear FE analysis are found to be in good agreement with the corresponding experimental values. The influence of mortar joint has been included in the stress-strain behaviour as a monolith with HCBM and not considered separately. The derived response reduction factors will be useful for the design of reinforced HCBM wall panels subjected to lateral forces generated due to earthquakes.

• 한국콘텐츠학회논문지
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• 제19권5호
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• pp.658-668
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• 2019

종합편성채널은 수년간 시사 대담 프로그램을 통해 정치적 영향력을 키워 갔지만 정치적으로 편향된 미디어라는 비판을 받고 있다. 본 연구에서는 2017년 7월부터 12월까지 6개월 동안 시사 대담 프로그램에 출연한 패널들의 특성과 함께 패널 발언과 정당 입장간의 상관관계를 분석하였다. 연구결과, 방송 프로그램에서 출연패널의 직군은 정치와 관련이 없는 중립적 직군으로 소개되었으나 이들의 정파성을 고려하여 재분류하면 정당인의 비중이 높아졌다. 또한 패널 발언의 정파성을 살펴본 결과, 대부분의 패널은 여당 혹은 야당의 입장을 견지하고 있었으며, 정당과 연관성이 많을수록 패널의 정파적 발언이 강해지는 것으로 나타났다. 향후 출연패널의 정파성이 명확하게 소개되어야 하며, 일관된 기준으로 장르를 구분하여 심의의 일관성을 확보할 필요가 있다. 또한 프로그램 제작진의 자율규제가 더욱 적극적으로 이루어져야 할 것이다.