• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.2
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• pp.69-77
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• 2009

The experiment was carried out to investigate lateral retrofitting effects by FRP and BRB (Buckling-Restrained Brace) for beam-column elements. These results were utilized to establish an analytical model using commercial nonlinear analysis software, PERFORM3D. Concrete and steel analytical models previously proposed by several scholars were adopted for this analytical study. A proposed analysis model showed reasonable accuracy compared with the test results on the beam-column elements strengthened FRP sheets and BRB, as well as with the non-strengthened element subjected to lateral cyclic loadings. Subsequently, the proposed modeling technique for nonlinear analysis would be helpful for preliminary analyses for retrofitting structures, by enabling engineers to estimate the improved capacity of retrofitted structural elements before performing construction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3785-3793
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• 2011

The purpose of this study is to devise the overall problems (such as, rights and obligations between users, owners, managers regarding commercial rental buildings, benefit/benefit in return, and the relevant regulations and systems) of the building maintenance system through field surveys, expert interviews, and literature reviews. In this rapidly changing society, there are a huge amount of needs for various reforms which can meet the diversity in each area, so it is greatly important to choose priority for the best improvement for efficient and economic expenses due to limited time, human resources and budgets. In this regard, the study extracted the evaluation elements from the devised problems with the viewpoint of BSC, calculated the weights through application of AHP to the extracted evaluation elements, evaluated the difference between before/after application of weights, and set the status, which makes it possible to realize the effective solutions and the reasonable expenses for all parties. By doing so, it is expected that the building maintenance system which maximizes the value and guarantees the user's convenience with smart functions of the building, will be realized in the near future.

• Korean Institute of Interior Design Journal
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• v.24 no.6
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• pp.13-21
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• 2015

The purpose of this study is to analyze the changing housing construction in Jeju-do which is composed of two cities(Jeju-si, Seogwipo-si). The number of indigenous population and migrating population of Jeju-do has been increasing every year because it has more beautiful scenery, interesting culture and a higher ratio of natural green area to urban area than other provinces(inland). More than 70% of population in Jeju-si is concentrated in dong-area. As a result, urban area and commercial area are expanding in entire Jeju-do. On the other hand, green area and non-urban area of Jeju-do are decreasing steadily. And there was a lot of changing during a short of time after 2010 because of internationalization and urban development etc.. This study is an analysis about the changing of housing in Jeju-do by statistical data. As a results of the analysis. I discovered that 1) The supply ratio of available housing in Jeju-do is higher than other inland cities in other parts of the country. 2) Housing constructing is influenced by moving-in and moving-out population. 3) There are more detached houses in Jeju-do than apartments. The opposite phenomenon occurs in other provinces (inland cities). However, the number of detached houses is gradually declining in Jeju-do since 2000. 4) Most detached homes in Jeju-do have an area of $60m^2{\sim}90m^2$. Most apartments have smaller areas than $60m^2{\sim}90m^2$. Seogwipo has homes with a larger area than Jeju-si. 5) The ratio of concrete structure houses is increasing at high speed because of constructing of apartment buildings, on the other hand, the ratio of brick structure house is decreasing gradually. Finally, Even though Jeju-do has different from housing culture of inland, it is changing slowly like inland housing types.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.112-119
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• 2005

Virtual reality(VR) is the technology that makes a user regard being in virtual space generated by computer as in the real world. Mainly, it has been studied about the three senses which are the sense of vision, touch and hearing in the five human senses. Through that, it is applied to the system making all the senses in the human body real. Even though the design idea of theater is brought to that of simulation theater, there are not many similarities between them and not general design rules yet. For making a better situation, in cooperation with a domestic company making a motion simulator for one or two person by itself, I have considered the minimum conditions and formations of the simulation theater being widely useful in the buildings of general commercial spaces from the environmental viewpoint, and basing on that facts I try to make some sorts of fundamental design types so that they are more available than those in the past. In this research, I have set the three types of simulation theater, the 50 seats of motion simulator for one person, the 20 seats of motion simulator and the 50 seats for two persons, in my researching range. Moreover, regarding the size of the simulation theater, I put the best specifications in order and also put them together, and then with making standards able to be reflected on the design plan, I have researched it for the purpose of the accumulation of skill in the construction of the special theater. Here, the design rule I suggested might be a design standard that it will be thought useful widely.

• Korean Institute of Interior Design Journal
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• v.23 no.3
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• pp.21-28
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• 2014

The purpose of this study is to analysis the change of rural house type in Gyeongbuk province. There are 13 Gun(a kind of administrative district) areas in Gyeongbuk province. According to definition of rural area, the scopes of the research of rural houses limited the 12 places rural area(Gun area, excluded Ulleung-Gun) of Gyeongbuk province. The method of study is to compare and analyze about housing situation, structure of house, housing type and housing area etc. through the statistical data of each Gun area and other various data etc. during these 5 years. As a results of the analysis : 1) The supply ratio of housing is steadily decreasing in rural areas. 2) The houses of rural areas are changing from a detached house to multi-household house and small apartment by development near the rural area. 3) The number and area of commercial buildings are gradually increasing because of urbanization of rural areas. 4) The most houses inside area scopes in the rural area was from $60m^2$ to $85m^2$ area. And the family types of rural house are changing from large family to nuclear family and single households. 5) The structure of rural houses is changing from the brick house type to lightweight steel construction house because of cost-cutting of construction and easy way to construct etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.709-714
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• 2017

Structures like bridges or buildings need to be checked continuously to diagnose their safety. However, it is extremely difficult for the people who access such structures to check all areas directly. To overcome this problem, there is a lot of active research into structural health monitoring (SHM) with wireless sensor nodes (WSNs). In this paper, for more accurate checking of SHM with WSNs, we experimentally compare and evaluate the performance of Xenomai, which provides real-time processing under the traditional Linux kernel. For this purpose, we patch Xenomai into the traditional Linux kernel of a commercial embedded board, Raspberry Pi, and implement a task that periodically reads vibration data of the z-axis from an accelerometer in order to analyze the natural frequency of cantilever beams. Reading the data from the traditional Linux kernel with the same method, we analyze the natural frequency of the cantilever beams using Smart Office Analyzer. Finally, to review the validity of Xenomai for WSNs, we obtain vibration data on the z-axis from the accelerometer via wired network and compared and analyzed them the same way.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1609-1618
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• 2015

DC microgrids are considered as prospective systems because of their easy connection of distributed energy resources (DERs) and electric vehicles (EVs), reduction of conversion loss between dc output sources and loads, lack of reactive power issues, etc. These features make them very suitable for future industrial and commercial buildings' power systems. In addition, the bipolar-type dc system structure is more popular, because it provides two voltage levels for different power converters and loads. To keep voltage balanced in such a dc system, a bidirectional dual buck-boost voltage balancer with direct coupling is introduced based on P-cell and N-cell concepts. This results in greatly enhanced system reliability thanks to no shoot-through problems and lower switching losses with the help of power MOSFETs. In order to increase system efficiency and reliability, a novel burst-mode control strategy is proposed for the dual buck-boost voltage balancer. The basic operating principle, the current relations, and a small-signal model of the voltage balancer are analyzed under the burst-mode control scheme in detail. Finally, simulation experiments are performed and a laboratory unit with a 5kW unbalanced ability is constructed to verify the viability of the bidirectional dual buck-boost voltage balancer under the proposed burst-mode control scheme in low-voltage bipolar-type dc microgrids.

• KIEAE Journal
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• v.16 no.6
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• pp.83-94
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• 2016

Purpose: A city is regarded as an organic living thing that generates, changes, and fades away in relationship with many components of city. Therefore, a city has its own identity based on its historical trace. Among these elements composing a city, it is a square that makes a city more active and dynamic. Piazza Navona in Rome, Italy has played its role as significant core in the city and has distinctive function from other squares in urban ecological environments. In this study, the distinguishing function and role of Piazza Navona will be defined. Another purpose of study is to figure out what factors of Piazza Navona attracts a lot of diverse people and activities. Method: First, general understanding of function, type, and history of piazza; Second, the historical background of Piazza Navona; Third, site analysis related to surrounding environments; Fourth, architectural characteristic of Piazza Navona in terms of plan and elevation; Fifth, comparing with other representative squares in Rome such as Piazza San Pietro, Piazza del Popolo, and Piazza del Campidoglio in aspects of urban function. Result: Piazza Navona provides both citizen and visitors with an inviting place to embrace all kinds of activities including assembly, annual festival, and daily events. Its functions in the urban environments also involve a tourist attractor as landmark, place for social and cultural interaction, market, and place for meeting and leisure. It is attributed to following factors; historical background as the city center since the first century AD; its location in the center of Rome; enough size and flexibility to accommodate many people and various events; open space enclosed by surrounding buildings; historical baroque structures and sculptures of fountains; synergy effect with commercial and other tourist attractors around Piazza Navona; and comfortable accessibility.

• Journal of Korean Association for Spatial Structures
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• v.4 no.2 s.12
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• pp.53-61
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• 2004

Recently, most of residential-commercial buildings and apartment houses which are being constructed in the downtown area mainly adopt hybrid structural systems to compose various spaces. Especially, column-supported wall system which is one of the hybrid systems includes shear wall and rigid frame structure and these structures are connected by the transfer floor. But this system is very disadvantageous from the viewpoint of structural safety and is difficult to find out the stress distribution at the transfer floor. Therefore, this study analyzes the behavior and stress distribution according to the shear wall layout of transfer girder system subject to vertical and static lateral loads. Also, this study recognizes load paths and stress concentration based on the analysis results nearby the transfer floor and presents guidelines for the effective design of wall and transfer girder.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.3
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• pp.156-163
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• 2013

Ground Source Heat Pump (GSHP) systems utilize geothermal energy as a thermal source or sink, for heating, cooling and domestic hot water. It is well known that GSHP is environmentally friendly, and saves energy dramatically. For this reason, many investigative researches have been conducted on commercial and governmental buildings. However, studies on residential GSHP are few, because of the small capacity and cost. In this study, we experimented with the characteristic performance of heating, cooling and seasonal performance factor for a residential GSHP system, which consisted of two 180 m deep u-tube ground heat exchangers, a heat pump and measurement instruments. The installed capacity of the heat pump was 5RT, and the conditioning area was $62.23m^2$. From the experimental results, the cooling COP of the heat pump was 4.13, and the system COP was 3.51, while the CSPF was 3.32. On the other hand, the heating COP of the heat pump was 3.87, and the system COP was 3.39, while the HSPF was 3.39. Also, in-situ cooling COP and capacity were 93.7% and 96.4% compared with the EWT certification data, respectively, and that of heating were 98.3% and 95.7%, respectively.