• Journal of Institute of Control, Robotics and Systems
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• v.3 no.3
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• pp.227-237
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• 1997

Autonomous Underwater Vehicles(AUVs) have become an important tool for various purposes in subsea: inspection, recovery, construction, etc., and the development of autonomous control system is luglay desirable- thete zffe many problems associated with designing the control system for AUV due to unknown underwater envimn-Tnent, the possibility of subsystem failures, and unpredictable changes in the dynamics of the vehicle. In this paper, an autonomous control system based on the intelligent control theory to enhance operation efficiency of the ALTV is presented. The control system has a hierarchical structure which consists of mission planning level, mission control level, navigation level, and execution level. The performance of the control system is investigated by computer simulation. The results show that the proposed control system can be applied successfully to the AUV in spite of the possibility of failures in the vehicle and the collision hazard in the sea environment.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.24-31
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• 1997

Recently, in Korea, demand for establishment of systematic risk assessment techniques for construction projects has increased, especially after the large construction failures occurred during construction such as New Haengju Bridge construction projects, subway construction projects, gas explosion accidents etc. Most of existing risk analysis modeling techniques such as Event Tree Analysis and Fault Tree Analysis may not be available for realistic risk assessment of construction projects because it is very complex and difficult to estimate occurrence frequency and failure probability precisely due to a lack of data related to the various risks inherent in construction projects like natural disasters, financial and economic risks, political risks, environmental risks as well as design and construction-related risks. Therefor the main objective of this paper is to suggest systematic probabilistic risk assessment model and demonstrate an approach for probabilistic risk assessment using advanced Event Tree Analysis introducing Fuzzy set theory concepts. It may be stated that the Fuzzy Event Tree AnaIysis may be very usefu1 for the systematic and rational risk assessment for real constructions problems because the approach is able to effectively deal with all the related construction risks in terms of the linguistic variables that incorporate systematically expert's experiences and subjective judgement.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.23-32
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• 2015

This paper addresses the effects of extreme rainfall on the stability of cut slopes in Yen Bai city, Northern Viet Nam. In this area, natural slopes are excavated to create places for infrastructures and buildings. Cut slopes are usually made without proper site investigations; the design is mostly based on experience. In recent years, many slope failures have occurred along these cuts especially in rainy seasons, resulting in properties damaged and loss of lives. To explain the reason that slope failure often happens during rainy seasons, this research analyzed the influence of extreme rainfalls, initial ground conditions, and soil permeability on the changes of pore water pressure within the typical slope, thereafter determining the impact of these changes on the slope stability factor of safety. The extreme rainfalls were selected based on all of the rainfalls triggering landslide events that have occurred over the period from 1960 to 2009. The factor of safety (FS) was calculated using Bishop's simplified method. The results show that when the maximum infiltration capacity of the slope top soil is less than the rainfall intensity, slope failures may occur 14 hours after the rain starts. And when this happens, the rainfall duration is the deciding factor that affects the slope FS values. In short, cut slopes in Yen Bai may be stable in normal conditions after the excavation, but under the influence of tropical rain storms, their stability is always questionable.

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.5-12
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• 2014

A slope may fail after construction owing to external factors such as localized rainfall, earthquake, and weathering. Therefore, the grasp of failure probability for slope failures is necessary to maintain their stability. In particular, it is very difficult to detect the symptoms of rock slope failure in advance by using traditional methods, such as displacement due to the brittleness of rocks. However, Acoustic Emission (AE) techniques can predict slope failures earlier than the traditional methods. This study grasped failure probability of slope by applying AE techniques to a rock slope with a history of collapse. When applying AE techniques to a slope that has a high probability of failure, the grasp of failure probability of the specific location became possible.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.220-223
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• 2004

Remodelling projects have recently emerged as an alternative construction market. Due to the limited experience of such projects, repetitive mistakes and failures in project management become concerns for those in the market sector. The objective of this paper to report preliminary findings in relation to core project management issues in office remodelling projects based on literature review and expert interviews.

• Journal of the Korean Professional Engineers Association
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• v.30 no.2
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• pp.52-60
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• 1997

As a matter of fact, the better architecture is very important things to create our generation and culture. Also, construction quality improvement is critical necessary to keep the culture and international competition which must be obtained through the consciousness reform of persons concerned. Therefore, the purpose of this proposal is to provide the basic point for establishing a practical compaign against construction failures. In this year, we have to remember the facts that's faced on market opening in construction market which is agreed in WTO. The contents of subject are as follows : 1 ) Subconscious reform of technician and projector concerned 2) Responsable consciousness of original contractor 3) Workmanship of skilled labor 4) Reasonable budget and bidding included sub-contractor 5) Advanced design and engineering quality 6) Certification of consulting engineer

• The Journal of Bigdata
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• v.4 no.1
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• pp.129-142
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• 2019

Construction projects have experienced many failures due to incomplete production environments. Thus, the purpose of this study is to use ICT resources leased during the construction period at the construction site and to introduce the Mobile Cloud Computing Service, which utilizes Cloud Computing Service and mobile devices such as smart phones, tablet PCs, and notebooks instead of physically wired communication networks. The characteristics of Mobile Cloud, such as rapid accuracy, shared collaboration, and ubiquity, will affect the social network among various construction site participants. we conducted empirical research on the introduction of Mobile Cloud to promote information exchange and convergence among the participants and mutual trust, ultimately improving the project performance.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1161-1170
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• 2009

The Roads in Gangwon Province generally was made on purpose to use the military road. In case of these roads, tremendous dangerous cut slopes do exist and its road linear shape was badly designed. In order to make up for this situation, the government has continuously established the new road or performed the public works such as the straight line of the curved road. Soksil 2 cut slope was made through the road improvement work. This has small surface failures and collapses. In spite of dry season, this slope are leaking lots of groundwater at the unbelievable point. So as to get curious phenomenon right, we performed a detailed field investigation, the geomorphological analysis, the stability analysis considering field characteristic and ultimately proposed the countermeasure to make sure stability of Sokil 2 cut slope.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.73-82
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• 2023

Optimization of Construction Site Layout Planning (CSLP) heavily relies on workers' travel paths. However, traditional path generation approaches predominantly focus on the shortest path, often neglecting critical variables such as individual wayfinding tendencies, the spatial arrangement of site objects, and potential hazards. These oversights can lead to compromised path simulations, resulting in less reliable site layout plans. While Deep Reinforcement Learning (DRL) has been proposed as a potential alternative to address these issues, it has shown limitations. Despite presenting more realistic travel paths by considering these variables, DRL often struggles with efficiency in complex environments, leading to extended learning times and potential failures. To overcome these challenges, this study introduces a refined model that enhances spatial navigation capabilities and learning performance by integrating workers' visibility into the reward functions. The proposed model demonstrated a 12.47% increase in the pathfinding success rate and notable improvements in the other two performance measures compared to the existing DRL framework. The adoption of this model could greatly enhance the reliability of the results, ultimately improving site operational efficiency and safety management such as by reducing site congestion and accidents. Future research could expand this study by simulating travel paths in dynamic, multi-agent environments that represent different stages of construction.

• Journal of the Korea Safety Management & Science
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• v.22 no.3
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• pp.23-29
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• 2020

As the duty to report and investigate major elevator failures has expanded due to the total amendment of the Elevator Safety Management Act in 2018, more important information on major elevator failures that have been partially identified has been collected. As of 2019, the number of elevators in Korea exceeded 700,000, making it the eighth-class elevator powerhouse in the world, but there is a trend of increasing casualties due to accidents and breakdowns. An Seung-gang-gi is a term that encompasses an elevator that moves vertically and an escalator that moves horizontally. It is an important means of transportation for most citizens that are encountered almost every day in daily life, and it is also necessary as a means of transportation that enables the construction of skyscrapers. And it seems that its importance will never diminish in the future. Major elevator failures are the main cause of dispatch when accumulating the number of 119 dispatches, and the frequency of occurrence is high. It's a shame. According to Heinrich's Law, 300 minor signs and danger phenomena precede, 29 minor accidents and 1 major accident. Accidents caused by elevators are increasing every year due to the increase in the number of installations, and the damage is threatening the valuable lives and property of users and workers in related fields due to fatal risks such as death and serious injury. Elevator safety management can achieve its purpose only when it is managed with the usual interests, awareness of safety, and full efforts of the users, workers, and the government concerned. This study was analyzed based on 2019 data notified to the Korea Elevator Safety Agency on major breakdowns improved after the revision of the Elevator Safety Management Act in 2018, and a total of 8,256 data were analyzed using the SPSS 21 version, a statistical analysis tool, to analyze the correlation with technical statistics. Proceeded. Through the analysis, it was possible to obtain preventive safety management data to prevent serious elevator safety accidents from occurring, and to derive meaningful implications that related safety management and maintenance can be effectively operated to prevent serious failures. In addition, through this analysis, we expect the development of related industries and legal and institutional improvement.