• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.698-707
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• 2002

A review is presented of experimental studies on the strength performance of concrete exposed at short-term and rapid heating as in a fire and after cooling. Emphasis is placed on concretes with high original compressive strengths, that is, high-strength concrete(HSC). The compressive strength-temperature relationships from the reviewed test programs are distinguished by the test methods used in obtaining the data(unstressed, unstressed residual strength, and stressed tests) and by the aggregate types(normal or lightweight), The compressive strength properties of HSC vary differently with temperature than those of NSC. HSC have higher rates of strength loss than lower strength concrete in the temperature range of between 20$^{\circ}C$ to about 400$^{\circ}C$. These difference become less significant at temperatures above 400$^{\circ}C$ compressive strengths of HSC at 800$^{\circ}C$ decrease to about 30 ％ of the original room temperature strength. A comparison of lest results with current code provisions on the effects of elevated temperatures on concrete compressive strength and elastic modulus shows that the CEN Eurocodes and the CEB provisions are unconservative.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.39-48
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• 2016

According to the order receipt report over the past 10 years the overseas construction business total trades were 54.05% and 68.09% done by the Middle East and other industrial facilities respectively. In the Middle East based on data collected in 2014 the country with most overseas construction business is Saudi Arabia with 34.10%, and the industrial facility occupies the larger share with 56%. Overseas construction business is suffering from a reduction in work orders in the Middle East because of the recent oil price reduction. At this point of view, it is necessary to consider economy fluctuation for the diversification of construction type and work orders. This study analyzed, focusing in Saudi Arabia how the economical fluctuations of nations of progress can affect overseas construction business' trade orders. The analysis results demonstrated that most construction types depends on GDP, investment fund. Also industrial facility can be substituted with Architecture and civil engineering. This work is expected to be used as a basis for trade order amount maintenance and construction type diversification.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.12-20
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• 2016

Along with the change of national accounting, the importance of systematic management of assets is emphasized and the awareness that the concept termed Asset Management should be introduced to the construction field too to manage facilities. The present study is a basic study for the introduction of the concept Asset Management and proposed accounting guidelines(proposal) for public building maintenance cost that can clarify maintenance cost accounting. Existing literatures and current accounting standards were examined and the actual states of maintenance cost accounting of public buildings in A metropolitan city were examined to draw problems. For the practice guidelines(proposal), the types and contents of government office building maintenance expenditures were analyzed and items that must be treated as OPEX and CAPEX were presented. Expert interviews were conducted to verify the reliability of the items presented. The practice guidelines(proposal) were applied to the public buildings in A metropolitan city to identify situations of changes in asset values and review the effects of the practice guidelines(proposal) on increases in asset values. When applied to practices, the practice guidelines(proposal) suggested in the present study are considered to increase building asset values and provide consistent financial information to help stakeholders' decision making.

• Journal of Internet Computing and Services
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• v.18 no.3
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• pp.29-36
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• 2017

In these days, 3D dynamic simulation is closely related to many industries. In the past, physically-based 3D simulation was used mainly in the car crash or construction related fields, but it also plays an important role in movies or games today. Many mathematical computations are needed to represent the 3D object realistically, but it is difficult to process a large amount of calculations for simulation of application based on CPU in real-time. Recently, with the advanced graphic hardware and improved architecture, GPU can be utilized for the general purposes of computation function as well as graphic computation. Many approaches using GPU have been applied for various research fields. In this paper, we analyze the performance variation of two cloth simulation algorithms based on GPU according to the change of execution properties of GPU shaders in oder to optimize the performance of GPU-based cloth simulation. Cloth simulation is implemented by the spring centric algorithm and node centric algorithm with GPU parallel computing using compute shader of GLSL 4.3. We compare the performance of between these algorithms according to the change of the size and dimension of work group. The experiment is repeated to 10 times during 5,000 frames for each test and experimental results are provided by averaging of FPS. The experimental result shows that the node centric algorithm is executed in higher speed than the spring centric algorithm.

• Journal of the Korea Convergence Society
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• v.8 no.8
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• pp.255-265
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• 2017

The study analyzed previous studies on traditional markets and market modernization projects to analyze research trends and content related to traditional markets. Next, the study selected 4 traditional markets throughout the nation where there was promotion of market modernization projects to conduct field research and interviews about store modules, line of flow, facility configuration, and types of businesses. Empirical comparative analysis was conducted on construction hardware status through measurement and observation and data was collected on business environment and requirement characteristics by business type through interviews with merchant associations of the corresponding markets. Consistent standard was applied as much it was possible to comparatively analyze the 4 market modernization cases and on the unique characteristics of individual markets, the cause was determined in conjunction to the history of the business promotion process and regional characteristics. After the study, basic data to suggest guidelines in store modules by business type in traditional markets could be acquired and the study identified the facilities equipment standards that must be considered in future market modernization projects. Through this it will be possible to derive policy implications to minimize trial and error and guarantee business efficiency in future market modernization projects.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.9-17
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• 2009

Discomfort Glare from the artificial light sources is an important issue in assessment of lighting quality for healthy buildings. Glare, as a factor of the characteristics of brightness, which has been defined as the sensation produced by contrast and luminance within an entire field view, unfavorably influences the occupants who performs visual tasks. It may cause annoyance and discomfort by interruption of visibility. In the whole visual field, glare can be determined by effects of the position, the luminance and the size of the light source and brightness of the surroundings. Therefore, experimental equipment is required to maintain a constant visual lighting environment. Recent studies have been developed and used the instrument for glare sensation evaluation but the instruments showed some difficulties to verify the correlation of glare indicators. The instrument have been developed with reference to former studies. It is called the Glare Tester. This is consist of 2[m]-diameter vertical dome screen painted with white flat paint, and light sources installed inside the screen. These light sources can provide various range of brightness at any inner surface of the screen. 2 Glare light sources can provide the value of luminance within the range of $0{\sim}150,000[cd/m^2]$. Moreover, 12 light sources are used for background luminance and it can perform the value of luminance within the range of $0{\sim}350[cd/m^2]$. Several experiments have been conducted using this Glare Tester to evaluate the range of the visibility, the values of BCD and the glare sensation in lower and upper visual field.

• Journal of Conservation Science
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• v.32 no.3
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• pp.425-436
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• 2016

The Yakhyeon catholic church (Historic Site No. 252 in Korea) that was constructed in 1892 has been the first western brick structure to ever have existed and one of the most important historical materials in the Korean modern architecture. After a fire had broken out at the catholic church in 1998, the stained glass on the back wall, the slab glass (dalle de verre) introduced by Lee Nam Guy in 1974, was repaired in 1999 because of singe scorch and water leakage. An analysis of the coloration elements showed that yellow, red and green included Zn, K and Cd, respectively. The glass of red contained Se, dark green contained Mn and Cr, and blue contained Pb and S. According to material analysis, the masonry joint was identified dolomite ($CaMg(CO_3)_2$) and calcite ($CaCO_3$), which was observed plate, columnar, rhombic and square of crystalline particles. Meanwhile, ultrasonic velocity in the stained glass recorded low speed in the middle and lower right of the window (an average of 4,130 m/s). And the joint was measured the lowest physical properties of the top left and middle of the window (an average of 2,053 m/s). This study have showed that extensive physical damage was founded to the left and middle rather than the right side. In this respect, more research in needed to conserve the correlation between color and physical properties.

• Archives of design research
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• v.15 no.4
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• pp.177-188
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• 2002

A thousands of chairs have designed from the Victorian era to the present. Thonet's Nol4 chair in 1859, Wright's high-back chair in 1904, Ritveld's red/blue chair in 1917, Breuer's Wassily chair in 1925, Aalto's Paimio chair in 1932, Eames's DAR chair in 1948, Piero Gatti's Sacco chair in 1969, Starck's Von Volgelsang chair in 1984, Stumpf's Aeron Chair in 1992, Little's 'Coat of arms' chair in 1994 - the list of architects who have seized the opportunity to express their theories in the design of a chair is seemingly endless. Architects such as Machintosh(1868-1928), Wright(1807-1959), Aalto(1898-1976) included chairs within their artistic schemes for interiors and buildings. But as the manufacture of chairs moved away from the domain of the craftsman towards that of the industrial process, architects were also ideally positioned, with their background knowledge of engineering, to pioneer innovative chair design within the constraints of modern manufacturing technology. Beyond matters of function and structure, the fundamental worth of chairs, past or present, lies in their communication of attitudes, ideas and values. The persuasiveness of a chair depend on the clarity of its rhetoric. Chair has become an ideal medium for designers to make their visual statements and construct their individual manifestos. In chair design there is a ping-pong game played out between absurd and useful design, and this game is one way in which the design profession explores itself.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.588-594
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• 2020

This study proposes non-destructive rebound-hardness and ultrasonic testing methods to more accurately evaluate the residual structural performance of reinforced concrete structures in a fire. Techniques are also proposed to assess the stiffness used in the deflection calculation with natural frequencies obtained by vibration tests. In the compressive strength evaluation using rebound hardness, the residual compressive strength of thick specimens and a larger water/cement (W/C) ratio were shown to be large. The homogeneity of concrete at high temperature compared to ambient temperature conditions was assessed by the velocity of ultrasonic waves that penetrate the concrete, and it followed W/C or thickness of slab makes little different results. To assess the stiffness of fire-damaged slabs and increase in deflection, the natural frequency was measured by vibration tests and incorporated into the equation of the stiffness. The application of this technique to the slab experiment showed that it can be a very reasonable evaluation technique. In addition, to evaluate the residual strength of a member after fire, a test of the strength of a component was carried out during and after heating.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.12-20
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• 2015

After the great King Munmu constructed Donggung-palace and Wolji-pond in 674, original landscape could not be estimated due to lack of related materials for some 1,250 years until it was surveyed in 1922. Accordingly, the study, to estimate changes of Wolji-pond landscape more accurately, analyzed the study of Hara(1932) and pictures in the Japanese ruling period etc. - these had not been studied so far. The study results are as follows. As a result of comparing survey maps of 1922 and one of 1975, it was found that during 53 years, whole area excluding island showed eroded part by 2~4m, severely, there was mounding area which was lowered by 10m. And it was identified through survey map of 1922 and pictures of the 1950's that inside southern shore protection of the No. 1 construction site were many landscape-stones(景石) which can make imagine a hill; here was water path. Trace of such path etc. remained just before excavation. 2) The construction site No. 3 and 5 in peak shape were higher than construction site No. 1, 2, and 4. Accordingly, there is high possibility that construction stood on high stylobate. So it is wrong that construction site No. 3 and 5 are restored in same height as other construction sites. Comprehensive restoration basic plan made in 2012 was also wrong. As a result of estimating changes of landscape through pictures before excavation of Wolji-pond, the author could identify changes of landscape in mound area and pumice stones which showed much changes in drawing. The study has limit due to lack of space. But if more pictures can be analyzed, it could further help for estimating original landscape of Wolji-pond.