• New & Renewable Energy
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• v.18 no.1
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• pp.35-45
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• 2022

The renewable energy based MG is becoming one of the prominent solutions for greenhouse gas and constructing less power lines. However, how to procure the economics of MG considering the CO₂ emission and utility network impact is one of major issues as the proportion of renewable resource increases. This paper proposes the feasibility study scheme of campus MG and shows that the LCOE and CO₂ emission can be reduced by utilizing the excess power and introducing hydrogen system and plus DR. For this, the three cases: (a) adding the PV and selling excess power to utility, (b) producing and selling hydrogen using excess power, and (c) participating in plus DR are considered. For each case, not only the topology and component capacity of MG to secure economic feasibility, but also CO₂ emission and utility network effects are derived. If an electrolyzer with a capacity of 400 kW participates in plus DR for 3,730hours/year, the economic feasibility is securable if plus DR settlement and hydrogen sale price are more than 7.08¢/kWh and 8.3USD/kg or 6.25¢/kWh and 8.6USD/kg, respectively. For this end, continuous technical development and policy support for hydrogen system and plus DR are required.

• Journal of the Korean housing association
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• v.16 no.6
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• pp.101-109
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• 2005

As a circumstantial-existance character (the human character who takes action after grasping circumstances and fears things with reason) the Japanese were more interested in the active doctrines of Wang Yang-ming than other speculative studies. All of people were inhumanely incorporated into the rigorous class system under pressure in the samurai society. In the atmosphere of the society a natural phenomenon was understood as the ksana of change, and instead of the whole, the part was mainly described with emphasis on the reality. Therefore nature came near to the man after being reduced and then was symbolized in the Interior space. Also the classification of spaces, that is to say, the settlement of borders by the social position was shown in the great interior space like a labyrinth. As a self-existance character(the human style who carves out for and does not have a regard other's feeling), however, the Korean were much influenced by the Taoist Idea as they tried to be similar to nature in nature itself. Therefore the idea of Asaniskrota was in their origin. There was a tendency for space to be extended toward the outdoor in Korea, since the Korean people who are speculative and like to be natural tried to be close to nature. Therefore the division of spaces according to class and sexuality and the settlement of borders were already shown in outside by Che-Na-Num(Divided-Mass:Koren's own style). These are closely related with that houses were built after a village settle down in Korea while built before a village settle down in Japan. Architectural space consists of the interior and the exterior. The layout and (on of architectural space has a great variety of characters by region and culture. In other words, it can be understood which has a priority between the interior and the exterior in developing the layout and the form of architectural space. Belonging to the culture area of Chinese characters with Korea, Japan has maintained its own Identity. It has an identity in the layout and form of architectural space as well. Therefore, the architecture and architectural theories of the two countries were compared and analyzed with priority given to the traditional architecture, also the backgrounds of architecture and architectural theories of two countries were examined in this study. This study shows that each country has different characters in how to introduce nature, how to expand space and how to compose windows, including the view of nature and the cult of space. As a result, the space in Korean architecture has relatively the exterior-oriented character but in Japan architecture spatial character is interior-oriented. The interior-oriented character can be relevant to the word 'reduction' and the exterior-oriented character to 'extension' after all. Also it can be thought that each character has a great relation with climate and idea of people in power.

• Journal of the Korean GEO-environmental Society
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• v.18 no.5
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• pp.5-16
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• 2017

In the present work, a number of advanced three-dimensional (3D) parametric finite element numerical analyses have been conducted to study the behaviour of a single pile in consolidating ground from coupled consolidation analyses. A single pile with typical minimum and maximum ranges of fill height and clay stiffness has been modelled. The computed results demonstrate that the higher the height of the fill above the clay surface and the smaller the stiffness of the clay, the higher the dragloads and the negative skin friction-induced pile settlements. It has been found that the development of dragloads and pile settlement is more governed by the stiffness of the clay rather than the height of the fill. Positive shaft resistance is mobilised only after the average degree of consolidation is larger than 50%. Although the pile is installed when the degree of consolidation is 50% or more, relatively large negative skin friction can nevertheless develop on the pile. On the other hand, when a load is applied on the pile experiencing an increase in the negative skin friction with time during consolidation, the pile undergoes a large increase in the final settlement of up to 95% compared to that of a pile without axial load on the pile head. The allowable pile capacity when there is negative skin friction on the pile is reduced by about 4-11% compared to a pile without negative skin friction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.75-83
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• 2019

In order to fulfill the obligation to voluntarily reduce greenhouse gas emissions under the Paris Climate Agreement, the proportion of coal and nuclear power generation is reduced worldwide and national efforts are being made to spread renewable energy including solar power generation. Korea also intends to increase the proportion of renewable energy generation to 30~35% by 2040 by introducing laws and regulations. In addition, while the country is trying to apply solar power generation to sidewalks and roads, there is no research related to it in Korea. Therefore, as a precedent study to develop solar power generation roads, solar power generation concrete blocks applicable to sidewalks and plazas were developed and the applicability was evaluated by constructing them on the site. As a result of indoor experiment, compressive strength was measured by 25.5~35.7MPa and flexural strength was measured by 5.1~10.5MPa, which showed that all domestic standards were satisfied. However, the higher the unit cement amount, the lower the strength was measured according to the mixing of the broken fine aggregate. The absorption rate was 5.7%, which satisfied the domestic standard of 7% or less. As a result of the freeze-thawing test, the reduction rate of the compressive strength after 100 cycles was up to 6.3%. As a result of measuring the settlement amount after construction, the maximum of 2.498mm was measured and irregular settlement occurred in the overall area, which is because the resolution of the sand layer was poor during construction. Maintenance techniques of sidewalk concrete block and solar panel need to be established more efficiently through long-term operation in the further.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.91-101
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• 2019

Recently, small-scale excavation like ground cavity restoration and buried pipe replacement works are being carried out in urban area, in order to improve living convenience. This paper describes experiment results on the ground reinforcement method that can reduce the buried pipe damage, when the differential settlement occurred due to poor compaction of ground below the buried pipe. Plate load tests were conducted to evaluate a reinforcement effect of ground using concrete mat and expansion mat in the ground below the buried pipe. The results showed that the stress reduction ratio by concrete mat and expansion mat according to the surcharge load was about 46%~48% and 39%~42%, respectively. Therefore, the differential settlement of the buried pipe and the ground deformation below the buried pipes were reduced by the reinforcement effect of the concrete mat and expansion mat. This means that it is possible to prevent a buried pipe damage due to underground cavity and ground subsidence, if concrete mat and expansion mat are reinforced in the ground below the buried pipe or on the ground between the buried pipes.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.671-684
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• 2022

This study verified the stability of a high-strength combined buried pile retaining wall and its applicability in the field. A cast-in-place (C.I.P) retaining wall and the high-strength combined embedded pile retaining wall were compared and analyzed numerically. The numerical analysis assessed the ground behavior and stability (and thus field applicability) of a high-strength combined buried pile retaining wall using data measured in the field. The experimental results showed that the cross-sectional force and displacement of the high-strength bonded pile retaining wall were reduced by 13.6~19.7%, the shear force increased by 0.7~4.7%, and the bending moment increased by 4.5~8.8% relative to the values for the C.I.P retaining wall. Examination of the amount of subsidence in the ground around the excavation showed that the maximum settlement of the C.I.P retaining wall was 46.89 mm and that at the high-strength combined buried pile retaining wall was 39.37 mm. Overall, designing a high-strength combined embedded pile retaining wall by applying the maximum bending moment and shear force calculated using the elastic beam method to the site ground was shown to achieve the safety of all members, as member forces were generated within the elastic region.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.2
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• pp.191-201
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• 2024

In this study, three-dimensional finite element analysis was used to analyze the behavior of existing and reinforcing piles according to the pile support conditions for vertical extension remodeling. Cap support conditions (group pile, piled raft foundation) and pile tip conditions (rock, soil embedment) were considered as factors influencing existing and reinforcing piles behavior. For the quantitative analysis of existing and reinforcing piles, the displacement, load distribution ratio, and axial force by depth according to the analysis stage were analyzed. As a result of the analysis, it was confirmed that the largest settlement occurred in the reinforcing pile due to the pre-loading method. In particular, a large amount of settlement occurred in group piles regardless of the embedment conditions. In the piled raft foundation, it was confirmed that the displacement and load distribution ratio of existing piles and reinforcing piles were reduced due to the influence of the raft. The axial force by depth showed a difference between group pile and piled raft foundation, which appears to be a major factor affecting displacement and load distribution ratio. Based on the numerical analysis results, it was confirmed that cap support conditions and pile tip embedment conditions should be considered in the design of pile foundations for vertical extension remodeling.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.177-190
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• 2017

This paper presents the results of an experimental study on the effect of large underground station construction method under an existing pile supported bridge using reduced-scale model tests. A series of tests were conducted on design alternatives using 1g models for different design options for which tunnel structures were created considering the similitude law. Deformation fields obtained using the PIV analysis and LVDTs together with strains in tunnel structures were used to investigate the effect of the construction methods on the pile supported bridge. The results of the tests demonstrated that the pipe roof structure is more efficient in limiting the ground deformation as well as the settlement of bridge foundation than a 2-Arch tunnel. It is also shown that the PIV analysis can be effectively used in analyzing ground tunneling induced ground movement for cases in which a construction sequence governs ground movement.

• Geomechanics and Engineering
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• v.15 no.5
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• pp.1061-1070
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• 2018

The main purpose of retaining wall methods for deep excavation is to keep the construction site safe from the earth pressure acting on the backfill during the construction period. Currently used retaining wall methods include the common strut method, anchor method, slurry wall method, and raker method. However, these methods have drawbacks such as reduced workspace and intrusion into private property, and thus, efforts are being made to improve them. The most advanced retaining wall method is the prestressed wale system, so far, in which a load corresponding to the earth pressure is applied to the wale by using the tension of a prestressed (PS) strand wire. This system affords advantages such as providing sufficient workspace by lengthening the strut interval and minimizing intrusion into private properties adjacent to the site. However, this system cannot control the tension of the PS strand wire, and thus, it cannot actively cope with changes in the earth pressure due to excavation. This study conducts a preliminary numerical analysis of the field applicability of the controllable prestressed wale system (CPWS) which can adjust the tension of the PS strand wire. For the analysis, back analysis was conducted through two-dimensional (2D) and three-dimensional (3D) numerical analyses based on the field measurement data of the typical strut method, and then, the field applicability of CPWS was examined by comparing the lateral deflection of the wall and adjacent ground surface settlements under the same conditions. In addition, the displacement and settlement of the wall were predicted through numerical analysis while the prestress force of CPWS was varied, and the structural stability was analysed through load tests on model specimens.

• Journal of Dairy Science and Biotechnology
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• v.14 no.1
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• pp.43-56
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• 1996

The world dairy industry has been driving their dairy policy on the basis of the self-supportihg principle. With progressing the GATT negotiation, the objective production amount has been reduced to maintain the optimum level, which decreasing the extra supply and over-stock before the U.R talks. The Oceania countries, where has the price competition capability, are continually increasing the milk production amount. Even through the USA is trying to increase their production amount with new export policy, the U.S.S.R collapse-down caused to decrease the milk production in world-wide basis. Because the U.S.S.R produced the highest amount of milk in the world. Moreover Europe Union countries, which recorded the half amount of dairy products in the world was decreasing their milk production. Therefore, about 4% of shortage is encountering at major dairy production countries in the standpoint of supply and demand. The drastic increasement of foreign dairy product import affects the domestic dairy industry with raw milk replacement and new dairy food demands creation since 1995, the initial period of free import system. Now, the domestic dairy industry are facing the inevitable problems such as the correction of producting and processing system. First of all, our dairy industry should resettle down the dairy production structure on the basis of self-supply of raw milk and offer the accurate dairy food informations. We still need to improve the raw milk quality. Also, more efforts are needed to have proper raw milk price policy. General domestic policies including the settlement of raw milk supply and demand, the reliability of inspection system in raw milk, ideal raw milk price system, centralization of raw milk collection, specially separated dairy organization should be improved legally in our dairy industry.