• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.401-408
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• 2021

With the proposal of amendments to the Pedestrian Safety Act in 2021, when the amendment bill is passed in the near future, a general dimensional investigation of the sidewalks' physical condition, which is the basis of pedestrian safety, is expected to be legislated and made mandatory. Therefore, this study presented a affordable methodology for street environment survey using entry-level drones and examined the feasibility of conducting a complete survey of pedestrian paths by local governments nationwide. To this end, various street facilities in the experimental site were measured to compare and analyze the accuracy of the point cloud data. As a result of the analysis, it was found that the measurement error range satisfies the public surveying guidelines. If the methodology presented in this study is applied, it is expected that individual local governments will be able to make a significant contribution to monitoring the physical conditions of streets to improve the pedestrian environment in the near future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.4
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• pp.353-366
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• 2021

Objectives: An appropriate level of cost support is being proposed to maximize the participation rate. In addition, as the amount of support is highly concentrated at the level of the limit under the current level of supports, the level of cost support is low when the actual level of cost of measuring the working environment exceeds the limit. This paper describes the adjustment of an appropriate cost support rate. Methods: First, this paper analyzes the current cost support status using data from the KOSHA. Second, an alternative for adjusting the cost support rate is presented in consideration of the incentive aspect. Third, we present simulation results for the average cost support rate, the impact of each alternative on finance, and more. Fourth, the most desirable adjustment method is presented after comparing and analyzing the results of various alternatives. Results: In this paper, we present a new scale model. This model is a mixture of flat-rate, fixed rate, and subside cap. It is expected that the new model will not only facilitate participation in businesses with low measurement costs, but also have the effect of controlling measurement costs for institutions that incur greater costs. It is also expected that setting a cap will have the effect of considering government finances and inducing excessively costly institutions to reduce costs. Thus, the new model is likely to be superior to others. If the fourth plan is applied to new businesses and the fifth plan is applied to sustainable businesses, the average cost support rates will be 87.68 percent and 65.18 percent, respectively, and the needed finances will be 2.5 billion won, 18.8 billion won, and 21.3 billion won in total. Conclusions: It seems most desirable to introduce a new model that combines flat-rate, fixed-rate, and subsidy cap systems and achieve an appropriate cost support rate through this model.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.3-14
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• 2022

Quantitative analysis of the number of construction workers and construction period can present a new standard for appropriate personnel. This study presents a Queueing model that predicts the execution time of work procedures, the most important factor among work efficiency indicators. During the working cycle of apartment frame construction the same process tends to be repeated the volume of contruction. Based on these characteristics, this study used a Queueing Model and analyzed reference layer cycle of the delayed frame construction. After adjusting the number of people and the construction period, the performance of the model was analyzed and suggested. This study aims to support the decision making of personnel distribution according to the volume of construction by performing a performance analysis of the Queueing Model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.324-327
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• 2022

Crack inspection of aged structures is mostly conducted by inspectors using surveying tools on site and visually inspecting them. This method greatly depends on professional worker, and consumes a lot of time and money. An artificial intelligence image classification algorithm is used to make reliable and objective judgments. Since 2018, image augmentation techniques have been used in the image pre-processing stage as they lead to high performance improvement. In this study, an analysis algorithm for cracks in concrete structures was developed using image augmentation techniques, in which the accuracy and speed according to the augmentation ratio were compared and measured for optimization. As a result, it was found that 8 times of image augmentation was appropriate when the accuracy was improved and economic feasibility was taken into account.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1D
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• pp.71-77
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• 2010

This study presented the operation method through of productivity on eight analysis work items (TBM boring, cutter check and exchange, TBM maintenance, succeeding facilities, reinforcement in tunnel, operation alternation, a tram car) which have developed equipment at WRITH with TBM a waterway tunnel works. It was inquired lose time with analyzed result by work items and removed lose time. It was analyzed TBM boring length, TBM boring length percentage and TBM boring length time. This study analyzed TBM operation utility factor of a foreign work with TBM operation boring length percentage, a monthly average boring length, pure boring length percentage etc. and assumed a monthly average boring length and a monthly average boring length of rise forecast. Based on analyzed Data, TBM boring has been forecasted propriety pure boring length at compressive strength $675{\sim}1662kgf/cm^2$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.677-684
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• 2008

The paper provides an approximate cost estimating model that can be used for tunnel. Based on the previous study analyzed critical factors that have impact on tunnel construction cost, this paper establishes a cost variance index table that reflects the cost impacts due to the change of the critical cost factors. An estimating procedure is described utilizing the index table. For the verification of the suggested model, the comparison of the estimated construction cost with real project cost is performed. The estimated results range from 95%~111% of the real project costs. As an approximate tunnel cost estimating model, the model can be utilized to quickly estimate tunnel construction costs based on the conceptual information at the planning stage and to efficiently make a decision on design alternatives.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.341-348
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• 2023

In this study, in order to minimize the increase in the amount of various industrial by-products due to the rapid growth of the industry and the intensification of the depletion of natural aggregate resources, the material test using recycled aggregate and steelmaking slag and the proper mixing ratio of recycled concrete were to be derived. In this study, first, the conformity of the quality standards of the materials used in the field was confirmed, and the workability and molding results were shown when used alone or mixed. Therefore, the feasibility of application as aggregate for concrete was evaluated through a total of 4-type mixtures of cement types, admixtures, coarse aggregates, and fine aggregates. As a result of the experiment, it was confirmed that the slump of unhardened concrete, the amount of air, chloride and compressive strength of hardened concrete according to the replacement rate were different from the measured values of general concrete quality characteristics. According to this, it was confirmed that the quality characteristics of the standard design criteria were satisfied.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.209-216
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• 2024

Land shrimp farms can control the growth environment more stably than coastal ones, making them advantageous for high-quality, large-scale production. In order to maintain an optimal shrimp growth environment, various factors such as water circulation, maintaining appropriate water temperature, oxygen supply, and feed supply must be managed. In particular, failure to properly manage water quality can lead to the death of shrimp, making it difficult to have people stationed at the farm 24 hours a day to continuously manage them. In this paper, to solve this problem, we design an integrated monitoring system for land farms that can be operated with minimal manpower. The proposed design plan uses IoT technology to collect real-time images of land farms, pump status, water quality data, and energy usage and transmit them to the server. Through web interfaces and smartphone apps, administrators can check the status of the farm stored on the server anytime, anywhere in real time and take necessary measures. Therefore, it is possible to significantly reduce field work hours without the need for managers to reside in the farm.

• Journal of the Korea Institute of Building Construction
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• v.24 no.3
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• pp.309-318
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• 2024

This research investigated the feasibility of incorporating industrial by-products into precast concrete formulated with blast furnace slag and natural gypsum. Specifically, the study examined the effects of incorporating steelmaking slag(STS slag), combined heat power plant fly ash, and return dust. The optimal amount of these by-products was determined by measuring air content, slump, and compressive strength at various incorporation levels. Results demonstrated that compressive strength was enhanced across all levels of by-product addition. Notably, incorporating 10% of the by-products led to exceptional early-age strength development. However, a 20% addition of combined heat power plant ash significantly reduced the slump value by approximately 40%. Considering these findings and the requirement for rapid strength development in precast concrete applications, a 10% incorporation of industrial by-products was deemed optimal due to its ability to accelerate early-age strength gain.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.19-29
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• 2022

The result of a questionnaire survey conducted on fishermen using coastal fish traps shows that fall accidents during trap dropping and pulling constitute the highest proportion of accidents at 42.1 %, whereas slipping accidents on the deck or stricture accidents to the body due to the trap winding device constitute 21.1 % each. In addition, 53.2 % of all surveyed subjects responded that trap pulling is the most dangerous task, followed by fish sorting 33.8 %, and trap dropping 9.1 %. As for the main items requested by fishermen for improving the trap winding device, 36.8 % indicated a method to easily lift the trap from the water to the work deck, and 31.6 % indicated a method to overcome the rope tension and prevent slip when pulling the trap to reduce the accidents. The small trap fishing vessel winding device proposed herein can increase the winding force by strengthening the rope contact area and friction coefficient via an appropriate contact angle between the driving roller of the winding device and the rope. When the contact angles between the driving roller and the rope are 1°, 5°, 9°, 14° and 19°, the rope tension showed a difference according to each contact angle. When the contact angle is 9°, the rope tension is the highest at 392.62 kgf. Based on these experimental results, a prototype winding device is manufactured, and 25 traps are installed on a rope with a total length of 100 m at 4 m intervals in the sea, and then the rope tension is measured during trap pulling. As a result, the rope tension increases rapidly at the initial stage of trap pulling and shows the highest value of 31.89 kgf, which subsequently decreases significantly. Therefore, it is appropriate to design the winding force of a small trap fishing vessel winding device based on the maximum tension value of the rope specified at the beginning of the trap pulling operation.