• Smart Structures and Systems
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• v.19 no.1
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• pp.11-20
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• 2017

For structural damage detection of shear buildings, this paper proposes a new concept using structural element mass-stiffness vector (SEMV) based on special mass and stiffness distribution characteristics. A corresponding damage identification method is developed combining the SEMV with the cross-model cross-mode (CMCM) model updating algorithm. For a shear building, a model is assumed at the beginning based on the building's distribution characteristics. The model is updated into two models corresponding to the healthy and damaged conditions, respectively, using the CMCM method according to the modal parameters of actual structure identified from the measured acceleration signals. Subsequently, the structural SEMV for each condition can be calculated from the updated model using the corresponding stiffness and mass correction factors, and then is utilized to form a new feature vector in which each element is calculated by dividing one element of SEMV in health condition by the corresponding element of SEMV in damage condition. Thus this vector can be viewed as a damage detection feature for its ability to identify the mass or stiffness variation between the healthy and damaged conditions. Finally, a numerical simulation and the laboratory experimental data from a test-bed structure at the Los Alamos National Laboratory were analyzed to verify the effectiveness and reliability of the proposed method. Both simulated and experimental results show that the proposed approach is able to detect the presence of structural mass and stiffness variation and to quantify the level of such changes.

• International Journal of Fluid Machinery and Systems
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• v.5 no.4
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• pp.143-151
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• 2012

Predicting the future condition of machine and assessing the remaining useful life are the center of prognostics. This paper contributes a new prognostic method based on grey model and survival probability. The first step of the method is building a normal condition model then determining the error indicator. In the second step, the survival probability value is obtained based on the error indicator. Finally, grey model coupled with one-step-ahead forecasting technique are employed in the last step. This work has developed a modified grey model in order to improve the accuracy of prediction. For evaluating the proposed method, real trending data of low methane compressor acquired from condition monitoring routine were employed.

• Journal of the Korean Institute of Landscape Architecture
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• v.13 no.2
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• pp.71-90
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• 1985

^x This study is composed of four Process. Process 1 suggests the background, purpose and necessity to provide with criteria for establishing Korean-style house preservation area including the present situation of the established area in our country. Also it is provided with the approach and the substantial realm to discuss the established criteria for the subject of this thesis. Process 2 dealt with theoretical parts as a premise to suggest the established criteria for the Korean- style house preservation area : 1) Original background of the Korean- style house, characteristic of the Korean traditional housing, changed situation of the Korean- style house based on the epoch, classified into the characteristic of the Korean- style house. 2) The characteristic of the Korean- style house and its values existed in the present urban areas are investigated by synthesizing such contents. 3) The significance for establishing the preservation area of the Korean- style houses in urban areas which is insufficient systematically in suggested as follows : First, establishment of the preservation area of the Korean- style houses with regard to the traditional succession of cultural properties. Second, acknowledging preservation problems of cultural properties in our country due to the world- wide tendency, preservation of historical environment of new comprehensive concept for the preservation of cultural properties. Process 3, as a case study on the establishment of the preservation area, describes a framework for investigating and analyzing the status by reviewing the present situation of the Korean- style preservation area in Seoul city which is established as the preservation area. Process 4 suggests seven criteria with regard to the establishment of the preservation area. 1) A decisive criterion for the Korean- style house to divide into Korean- style house and non- Korean style house (proper building and nonproper building) for the preservation. 2) A concrete decisive criterion for the Korean- style house with regard to valuable endowment with dominent factors in its landscape. 3) A decisive criterion for the review of the landscape preservation for the nonproper building. 4) Suggesting logical evidences for the above second and third criterion (suggesting appropriateness). 5) Dividing into following two criteria for the decision of the building condition. a) A decisive criterion of the Korean- style house's condition. b) A decisive criterion of non- Korean style house's condition. 6) A selective criterion for the preservation building after synthesizing above five criteria. 7) Final criterion for establishing the preservation area with regard to systematic particulars.

• Earthquakes and Structures
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• v.12 no.3
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• pp.349-357
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• 2017

The design of reinforced concrete structures strongly depends on the value of the compression concrete strength used for the structural components. Given the uncertainties involved on the materials quality provided by concrete manufacturers, in the construction stage, these components may be either over or under-reinforced respect to the nominal condition. If the structure is under reinforced, and the deficit on safety level is not as large to require the structure demolition, someone should assume the consequences, and pay for the under standard condition by means of a penalty. If the structure is over reinforced, and other failure modes are not induced, the builder may receive a bonus, as a consequence of the higher, although unrequested, building resistance. The change on the building safety level is even more critical when the structure is under a seismic environment. In this research, a reliability-based criteria, including the consideration of expected losses, is proposed for bonification/penalization, when there are moderated differences between the supplied and specified reinforced concrete strength for the buildings. The formulation is applied to two hypothetical, with regular structural type, 3 and 10 levels reinforced concrete buildings, located on the soft soil zone of Mexico City. They were designed under the current Mexican code regulations, and their responses for typical spectral pseudoaccelerations, combined with their respective occurrence probabilities, are used to calculate the building failure probability. The results are aimed at providing objective basis to start a negotiation towards a satisfactory agreement between the involved parts. The main contribution resides on the explicit consideration of potential losses, including the building and contents losses and the business interruption due to the reconstruction period.

• Journal of Wetlands Research
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• v.16 no.4
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• pp.327-333
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• 2014

The vegetation composition for river restoration requires the introduction of plants which have strong flooding tolerance. A study of the growth characteristics of river plants according to the period of flooding is essential. Accordingly, this study measured shoots, leaf number, leaf greenness, dry weight of the plants of Salix species, analyzed their growth rate according to flooding tolerance and the period of flooding, and contrasted the results with those of a flooding experiment in turbid water. The results of this experiment showed that Koreensis is the plant which has the strongest flooding tolerance and flooding in fresh water leads to a much lower risk of the plants being withered than in high turbid water. In addition, the results showed that the condition of the period of flooding of twenty days and under contributes to more growth and development of the plants of Salix species than the condition of non-flooding.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.3
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• pp.125-132
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• 2011

By this time the main tendency of studying traditional residential building was to find out and analyze the regional and spacial peculiarity. But that kind of study has been set limits in terms of including each building into one category and being researched by the viewpoint of an observers rather than a resident. Due to this kind of problem, the outcome of that study didn't obtain good results. This study, which has synthetically not been investigated until now, have put a little more deep interpretation on traditional residential building, by surveying Andong Kwon family's Yuhoedang-Chongga located 299 Musudong Daejon. The purpose of this study is to investigate the characteristic of construction in the architecture of Yuhoedang-Chongga of the Andong Kwon family, and to develop the viewpoint and analytic process of traditional construction. As the first step to study it efficiently, basic architectural investigation on Yuhoedang-Chongga has been carried out with an actual evidence, and the new viewpoint of traditional residential building has been developed by this survey such as collecting, arranging, analyzing and examining this positive proof. For example, from the house-picture book handed down from that family, the condition of then established was compared with the present state of it. And then this article examines the arrangement, floor-plan types, interior, structures and condition of location. The transition-history of this house was searched into, and the development process of this was examined. The related documents was synthetically analyzed, so the characteristics of this construction was grasped.

• Journal of the Korea Institute of Building Construction
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• v.12 no.5
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• pp.490-502
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• 2012

The use of recycled aggregate, even for low-performance concrete, has been very limited because recycled aggregate, which contains a large amount of old mortar, is very low in quality. To produce a high-quality recycled aggregate, removing the paste that adheres to the recycled aggregate is very important. We have conducted research on a complex abrasion method, which removes the component of cement paste from recycled fine aggregate by using both a low-speed wet abrasion crusher as a mechanical process and neutralization as chemical processes, and well as research on the optimal manufacturing condition of recycled fine aggregates. Subsequently, we evaluated the quality of recycled fine aggregate manufactured using these methods, and tested the specimen made by this aggregate. As a result, it was found that recycled fine aggregates produced by considering the aforementioned optimal abrasion condition with the use of sulfuric acid as reactant showed excellent quality, recording a dry density of 2.4 and an absorption ratio of 2.94. Furthermore, it was discovered that gypsum, which is a reaction product occurring in the process, did not significantly affect the quality of aggregates. Furthermore, the test of mortar using this aggregate, when gypsum was included as a reaction product, showed no obvious retarding effect. However, the test sample containing gypsum recorded a long-term strength of 25.7MPa, whereas the test sample that did not contain gypsum posted a long-term strength of 29.4MPa. Thus, it is thought to be necessary to conduct additional research into the soundness and durability because it showed a clear reduction of strength.

• Fire Science and Engineering
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• v.24 no.1
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• pp.81-89
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• 2010

In general, fire resistance is determined through the building' uses and stories. But recently a fire engineering design that is done by the calculation of design fires from the fire cell and an evaluation of stabilities for structural behavior at fire condition have applied to almost of countries as a major alternative against a prescriptive fire design. To adopt and utilize the fire engineering design into Korea, at first, we evaluated structural stability of 21st stories steel residential building at fire condition through fire engineering design and secondly the fire protection cost was analyzed with fire engineering design method and the prescriptive one, respectively. No fire protection materials for satisfaction of building law at structural members such as columns and beams were needed and about 90 % of fire protection cost was saved.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.402-405
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• 2003

As Remodeling is proceed in the limited condition that is utilization of existing resource, the selection of remodeling objects and scope are affected by the correlation of building systems. Unexpected problems have occurred in construction phase by lack of the consideration about correlation of building systems; increasing of cost, delaying of schedule etc. Therefore, this research suggests the Building System Correlation Diagram Model and the method for selecting the alternative reasonably in remodeling project.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.82-87
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• 2003

Domestic remodeling market is now growing centering around non housing building. Unlike non housing building remodeling business, understanding of remodeling demanders accustomed to profit of reconstruction, deficiency of experience performing remodeling project and construction, shortage of will performing remodeling policy and detailed action method are difficulties in performing apartment building remodeling business. Understanding change of remodeling demanders. strong economic incentive by government, construction management paradigm shift from new construction into building life cycle, application of construction method using existing building condition before remodeling and remodeling related industry infrastructure are required to improve this remodeling business circumstances.