• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.733-736
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• 2009

Power Line Communication(PLC) is need not additional communication line. So establishment expense is inexpensive and application is simple. Therefore, lower part network of various application field is possible. However, there are high subordinate interference and noise problem on limited transmission data and communication interference element. Wireless Sensor Network(WSN) is need not infrastructure, Self-regulating network architecture of sensor nodes is possible. So at short time, network construction is available. But, power consumption is increased by active sensing for QoS elevation and unnecessary information transmission, low electric power design and necessity of improve protocol are refered to life shortening problem and is studied. In this paper, supplement problem of power line communication and wireless sensor network mutually and because advantage becomes linkage integration control system using synergy effect of two technologies as more restriction be and tries to approach structurally control network that is improved for smooth network environment construction. Honeywell's hybrid sensor network does comparative analysis(benchmarking). Confirm performance elevation proposing teaming of power line communication and wireless sensor network. Through simulation, service delay decreases and confirms that performance elevation.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.500-512
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• 2022

Post-Occupancy Evaluation (POE), which is one of the construction environment evaluation methods, is a series of processes that ask about the functional requirements and satisfaction of an object from a life cycle perspective such as design/construction/residence. However, there are no POE research activities targeting large-scale units. On the other hand, large-scale third-phase new towns are being developed. Therefore, this study conducted a post-residence evaluation (POE) research activity in a large-scale unit (Multifunctional Administrative City). The procedure of this study is to conduct a literature survey on the current status and implications of the multi-functional administrative city area, and based on the research data, derive the Happy City evaluation index for the major issues and special issues of the Happy City. Afterwards, 450 questionnaires were conducted for the residents of Happy City, and POE analysis was performed on the derived data for each module. And based on the analysis results, implications such as problems and improvement points for the current status of the Happy City were derived. This can be used as a basis for the expansion of a large-scale new city into a self-sufficient city, and it can be used as a basic data for the development and improvement of a happy city that meets social needs in the future.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.111-116
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• 2022

Recently, building structures tend to be super high-rise and large-scale with the development of concrete technology. When high-rise building is constructed of reinforced concrete structure, it has a disadvantage that its own weight increases. Light weight aggregate(LWA) was developed to compensate for these shortcomings. Manufacturing concrete using these light weight aggregates has the advantage of reducing the self weight of the reinforced concrete structure, but has a disadvantage in that the strength of the concrete is reduced. In this study, an experimental study was conducted to investigate the strength characteristics of hardened cement according to the presence or absence of surface coating of lightweight aggregates. As a result, in terms of compressive strength, the surface-coated lightweight aggregate exhibited higher strength than the uncoated lightweight aggregate. Also, it was considered that this is because the interfacial voids of the surface coated lightweight aggregate mixed cement hardened body were filled with blast furnace slag fine powder particles.

• Journal of the Korean Geosynthetics Society
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• v.22 no.2
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• pp.85-92
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• 2023

This paper describes the comparative results of measured and predicted values for the horizontal displacement of earth retaining wall based on two field cases, in order to evaluate the application of lateral earth pressure to earth retaining wall supported by earth anchor in Jeju. The prediction of lateral earth pressure acting on the earth retaining wall was performed by elasto-plastic analysis using Rankine earth pressure, Hong & Yun lateral earth pressure, Terzaghi & Peck modified lateral earth pressure, and Tschebotarioff lateral earth pressure. As a result, the predicted value of the maximum horizontal displacement for site A was about 10 to 12 times greater than the measured value, and in the case of site B, the predicted value was evaluated as about 9 to 12 times greater than the measured value. That is, both sites showed a similar increase rate in the maximum horizontal displacement by the predicted value compared to the measured value. In all field construction cases, the maximum horizontal displacement by measured values occurred in the sedimentary layer, soft rock layer, and clinker layer, and the horizontal displacement distribution was shown in a trapezoidal shape. The maximum horizontal displacement by the predicted value occurred around the clinker layer, and the horizontal displacement distribution was elliptical. In the ground with a clinker layer, the measured value showed a very different horizontal displacement tendency from the predicted value, because the clinker layer exists in the form of a rock layer and continuous layer. In other words, it is unreasonable to apply the existing prediction method, which is overestimated, because the characteristics of the earth pressure distribution in Jeju show a tendency to be quite different from the predicted earth pressure distribution. Therefore, it is necessary to conduct a research on the lateral earth pressure in the realistic Jeju that can secure more economic efficiency.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.89-99
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• 2006

The PCRW (Precast Concrete Retaining Wall) has many advantages compared with cast in place concrete retaining wall : shorter construction period, excellency of quality and minimum interference with the adjacent structure and traffics. However, shallow foundation type of PCRW, which has comparatively better ground condition, has some disadvantages such as difficulty in transportation and higher cost due to the size of PCRW being expanded by resisting only with self-weight if there is no other supplementary reinforcement. The presented study, in order to complement such disadvantages of PCRW, have applied the micropile method. The micropile method has advantages like low-cost and high-efficiency and does not require huge space, because it can be executed with small size equipment. However, the mechanical behavior characteristics of the PCRW reinforced by micropile, which is installed to improve the reinforcement effect, is not yet clearly identified and there is no suggested standard as to the length, diameter, install angle and install position of micropiles. Hence, this method is yet being designed depend on engineer's experience. In this study, various laboratory model tests as to sliding and overturning were performed in order to identify and present the optimum type of reinforcement and reinforcement effect of the PCRW reinforced by micropiles. In addition, it also executed numerical analysis for the purpose of verifying the optimum type of reinforcement for micropiles based on the results of laboratory model tests. The optimum reinforcement type of micropiles was estimated by model test and numerical analysis. The length of micropiles is 0.4 times wall height and the diameter is 0.04 times wall length.

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.27-40
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• 2006

Damage of cut-and-cover tunnel lining can be attributed to physical and mechanical factors. Physical factors include material property, reinforcement corrosion, etc. while mechanical factors include underground water pressure, vehicle loads, etc. This study is limited to the modeling of rigid circular cut and cover tunnel constructed at a depth of $1.0{\sim}1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. In this study, only damages due to mechanical factors in the form of additional loads were considered. Among the different types of additional, excessive earth pressure acting on the cut-and-cover tunnel lining is considered as one of the major factors that induce deformation and damage of tunnels after the construction is completed. Excessive earth pressure may be attributed to insufficient compaction, consolidation due to self-weight of backfill soil, precipitation and vibration caused by traffic. Laboratory tunnel model tests were performed in order to determine the earth pressure acting on the tunnel lining and to investigate the applicability of existing earth pressure formulas. Based on the difference in the monitored and computed earth pressure, a factor of safety was recommended. Soil deformation mechanism around the tunnel was also presented using the picture analysis method.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.203-213
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• 2024

This study delves into the mechanical properties of fiber-reinforced cement composites(FRCC) concerning the dispersion method of multi-walled carbon nanotubes(MWCNTs). MWCNTs find utility in industrial applications, particularly in magnetic sensing and crack detection, owing to their diverse properties including heat resistance and chemical stability. However, current research endeavors are increasingly directed towards leveraging the electrical properties of MWCNTs for self-sensing and smart sensor development. Notably, achieving uniform dispersion of MWCNTs poses a challenge due to variations in researchers' skills and equipment, with excessive dispersion potentially leading to deterioration in mechanical performance. To address these challenges, this study employs ultrasonic dispersion for a defined duration along with PCE surfactant, known for its efficacy in dispersion. Test specimens of FRCC are prepared and subjected to strength, drawing, and direct tensile tests to evaluate their mechanical properties. Additionally, the influence of MWCNT dispersion efficiency on the enhancement of FRCC mechanical performance is scrutinized across different dispersion methods.

• Korean Journal of Heritage: History & Science
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• v.53 no.3
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• pp.80-109
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• 2020

The Sacheonwangsa Temple in Silla is an esoteric temple that was founded provisionally in 670, and was completed in 679. This study attempted to elucidate the planning method of the Sacheonwangsa Temple based on the results of research on excavations and investigations into its construction processes and construction measures thereof. The research results are as follows. (1) In the site construction, assuming the size of one Bang (坊) on the south of Nangsan Mountain, after dividing the north-south width into three equal parts, there is a possibility that two of these parts were set to the flat portion. (2) In the 'Jochang (祖創, 670)', it is estimated that an area of 300 cheoks by 300 cheoks was postulated on the flat surface, and, as an initial conception, the mandala's plane design of the outer square 2 hasta (3 cheoks) and inner square 1 hasta (1.5 cheoks) was originally devised for the setting of 'Mudra (神印)', and an area 100 times greater has been set as the basis in the scale and layout planning of the central block. (3) During 'Gaechang (攺刱, ~679)', it is judged that because of the narrowness of the distance between the Pagoda and Geumdang Hall, which occurs when the center of the Geumdang Hall coincides with the center of 'the first stage of the foundation (先築基壇)', the scale and layout planning were adjusted from the initial conception. (4) The arrangement of the building was determined by dividing the fixed size of the central block (280 cheoks by 320 cheoks). Specifically, the east-west direction is set on the quartile's line of the east-west width of the central block, and in contrast, the north-south direction is based on the structural characteristics of the central block. It is presumed that the position of the transept was determined through the division and adjustment of the column spacing of the east-west corridor, then the Geumdang Hall and Altar were based on this. (5) The scale of the Geumdang Hall and Pagoda is determined by the petition of the division by the unit fraction starting from the quartile's line of the central block's east-west width. This planning is understood to be based on the self-similarity, which is rooted in the mandala's plane design as the model.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.11
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• pp.471-480
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• 2023

The Korean construction order volume in South Korea grew significantly from 91.3 trillion won in public orders in 2013 to a total of 212 trillion won in 2021, particularly in the private sector. As the size of the domestic and overseas markets grew, the scale and complexity of EPC (Engineering, Procurement, Construction) projects increased, and risk management of project management and ITB (Invitation to Bid) documents became a critical issue. The time granted to actual construction companies in the bidding process following the EPC project award is not only limited, but also extremely challenging to review all the risk terms in the ITB document due to manpower and cost issues. Previous research attempted to categorize the risk terms in EPC contract documents and detect them based on AI, but there were limitations to practical use due to problems related to data, such as the limit of labeled data utilization and class imbalance. Therefore, this study aims to develop an AI model that can categorize the contract terms based on the FIDIC Yellow 2017(Federation Internationale Des Ingenieurs-Conseils Contract terms) standard in detail, rather than defining and classifying risk terms like previous research. A multi-text classification function is necessary because the contract terms that need to be reviewed in detail may vary depending on the scale and type of the project. To enhance the performance of the multi-text classification model, we developed the ELECTRA PLM (Pre-trained Language Model) capable of efficiently learning the context of text data from the pre-training stage, and conducted a four-step experiment to validate the performance of the model. As a result, the ensemble version of the self-developed ITB-ELECTRA model and Legal-BERT achieved the best performance with a weighted average F1-Score of 76% in the classification of 57 contract terms.

• Journal of Agricultural Extension & Community Development
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• v.5 no.1
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• pp.79-91
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• 1998

This study investigated and summarized the history of peasant movement which had been done by various peasant associations Yesan, Hongsong, and Tangjin from the beginning of Korean Catholic Peasant Movement from 1970 to 1995. First of all, we classified all the peasant movements(Yesan ; 120 times, Hongsong; 113 times and Tangjin; 107 times / total; 340 times) into 5 categories composed of movement time, movement type, movement method, the number of participators, and the movement subjects(issues). The frequency of peasant movement from 1990 to 1995, occupied 65.6%, which shows that the peasant movement was the most active during the time. The frequency of movement type, were we could find out, self-dependence type(62.9%), resistance type(15.6%) and request type(21.5%). The active way like congregation, demonstration, sit-in, rice file up struggle occupied 28.8% and it got the first place in movement way. In the movement subject category, the construction of organizations and solidarity activity amounted to 37.8% and democratization item(the union democratization and the social democratization related peasant) covered 16.8%. The 98 times of peasant movement were done in the active ways such as congregation and demonstration. However we cannot find these active ways in 1970s. In 1980s, the frequency of each item (congregation, demonstration, publicity and propaganda) was 28 times. But in 1990s, the frequency of congregation, or demonstration was higher than the others. The number of participators in peasant movement increased during 1980s∼1990s. The movement of which participators were 100∼499 was 32 times in 1980s and 70 times in 1990s each time. Such large scale movement amounted to over 30%. Furthermore, the large scale movement in which over 500 people participated amounted to 12 times in 1990s.