Hyun-Seok Yoo

WIRELESS VIBRATION SENSOR FOR TUNNEL CONSTRUCTION

During and after tunnel construction, many problems including civil petitions and construction delay result from tunnel deformation, ground settlement, ground vibration, and tunnel lining crack. In relation to tunnel construction and maintenance, this study explains a development background of small wireless vibration sensors and their applications based on RF(Radio Frequency)-MEMS (Micro Electro Mechanical System) technology. The advantages and usefulness of the wireless automatic monitoring system is addressed compared with the conventional wired or survey measurement systems. Thus, the study provides a framework of the process for monitoring, manipulating, and transferring data from MEMS sensor and explains the application of the new developed automatic monitoring system for tunnel construction and maintenance.

Application of Appropriate Technologies to 3D Local Terrain Modeling in Real-time for Intelligent Excavating System (IES)

Automation in construction is considered as one of solutions to fundamental problems which the construction industry has confronted. The development of real-time 3D local terrain modeling is the core methodology of achievement of IES (Intelligent Excavating System) which is a mega-size research concerning automation in construction. Stereo vision technique was selected as an appropriate method to achieve 3D terrain modeling in real-time. The objective of this study is to suggest a conceptual method by use of the stereo vision and assess feasibility of practical application under various conditions of construction sites. Bumblebee XB-3 is adopted as the stereo vision system in a prototype of a 3D terrain modeling system. This study is to investigate fundamental theories of the stereo vision system and to conduct tests in indoor and outdoor environments for determining appropriate detection range, finding installation location of cameras, doing visual assessment of the technical appropriateness, and checking reliability of 3D visual data. These decomposed tasks present valuable information for establishment of the conceptual method and improvement on the limitations of the use of stereo vision system for 3D terrain modeling in real-time.

A Decision Support Model for the Exchange Risk Management of Overseas Construction Projects

Overseas construction project orders have shown steady increase since 2001, and it took 44.5% of the total construction project orders in 2010. Overseas construction project needs more complex risk management because it is affected by more various circumstance factors than the domestic construction is. Previous studies have centered on the internal risk factors to assist the decision-making, but there are few researches on the importance and techniques of foreign exchange risk management. Inadequate management of foreign exchange risk has been found to cause huge damages due to the lacking recognition on the importance of foreign exchange risk management. Therefore, current study designed a foreign exchange risk manage model to help efficient management and decision-making. This model was developed as a technique to meet the demand of the increasing overseas construction projects for the efficient management of foreign exchange risk, and the technique will lower the risk with more and more accurate outcome by accumulating the data of profit-and-loss.

Development of MEMS-Based Vibration Sensor for Tunnel Construction and Maintenance Monitoring System

Recently, the demand for sensor technology has increased remarkably in all industrial fields. Sensor technology is closely related to cutting-edge technologies such as semiconductor technology and minute structure building technology, and thus, the high demand for small and light devices with high performance provides the impetus for conducting studies in order to develop sensors with much better performance. In this study, we developed a MEMS-based vibration sensor for tunnel construction and maintenance monitoring system. For this, we investigated the definition and summary of MEMS technology and also analyzed the types and characteristics of MEMS processing technology and the strong points of MEMS technology. We also analyzed current research results on sensor applications based on MEMS for construction. The types of work, characteristic and frequency of tunnel measurement, and investigated the characteristics of measuring instruments for doing the pertinent works are analyzed. We manufactured the MEMS vibration sensor for tunnel construction in order to measure blast vibration and we also measured the vibration through experiments.

A Study on Vitalizing Plans of Extension Remodeling for Apartment Housings

548 thousand apartment houses of Seoul has been used over 15 years and remodeling is available. It is 42% of the overall apartment houses currently and it is assumed to increase to 800 thousand in 2015. The maintenance work is divided to reconstruction and remodeling. Due to the regulations of the government, expansion remodelling has been the most considered alternative. However, 75% of the extension remodelling, yet, are in the preliminary phases. Thus, this study suggests factors hampering the vitalization of extension remodelling and solutions for each factor by means of Delphi analysis method.

The Development of an End-Effector in Automated Pavement Crack Sealer and Technical Feasibility Analysis

Crack sealing is a maintenance technique commonly used to prevent water and debris penetration and reduce future degradation in pavement. The conventional crack sealing operations are, however, dangerous, costly, and labor-intensive. Automating crack sealing will improve productivity and quality, and offer safety benefits by getting worker off the road. During the last two decades, several teleoperated and machine-vision assisted systems have been developed to automate the overall process of routing and sealing pavement cracks. However, the developed systems have not been commonly used in the construction sites because of the technical problems. Especially, the performance of end-effector, related to the productivity and quality improvement, is very important factor to improve the practical use of the developed systems. The main objective of this research is to develop an end-effector in automated pavement crack sealing machine and to analyze the technical feasibility of the developed end-effector.

Object Detection From 3D Terrain Data Gener Ated by Laser Scanner of Intelligent Excavating System(IES)

The intelligent excavating system(IES), the development in South Korea of which has been underway since 2006, aims for the full-scale automation of the excavation process that includes a series of tasks such as movement, excavation and loading. The core elements to ensure the quality and safety of the automated excavation equipment include 3D modeling of terrain that surrounds the excavating robot and the technology for detecting objects accurately(i.e., for detecting the location of nearby loading trucks and humans as well as of obstacles positioned on the movement paths). Therefore the purpose of this research is to ensure the quality and safety of automated excavation detecting the objects surrounding the excavating robot via a 3D laser scanning system. In this paper, an algorithm for estimating the location, height, width, and shape of objects in the 3D-realized terrain that surrounds the location of the excavator was proposed. The performance of the algorithm was verified via tests in an actual earthwork field.

A Study on the Conceptual Design and Technical Feasibility Analysis for the Development of Automated Pavement Crack Sealer

Crack sealing is a maintenance technique commonly used to prevent water and debris penetration and reduce future degradation in pavement. In recent years, several systems for automatically routing and sealing pavement cracks have been developed in the highway construction and maintenance area. Automating pavement crack sealing can improve safety, productivity and quality, and reduce road user cost as well. The reduction in crew size and the increase in productivity of the automated sealing process will be translated directly into significant potential cost savings. The main objective of this study is to illustrate conceptual models for the development of the automated pavement crack sealer which meets domestic road condition and regulation, and to discuss its technical feasibilities. Conclusions are made concerning the applicability and the value of cantilever-typed pavement crack which is selected as the most feasible alternative in both economical and technical aspects.

The development of a machine vision-assisted, teleoperated pavement crack sealer

Crack sealing is a maintenance technique commonly used to prevent water and debris penetration and reduce future degradation in pavement. The conventional crack sealing operations are, however, dangerous, costly, and labor-intensive. Labor turnover and training are also increasing problems related to crack sealing crews. Automating crack sealing will improve productivity and quality, and offer safety benefits by getting workers off the road. The reduction in crew size and the increase in productivity of the automated sealing process will be translated directly into significant potential cost savings. The main objective of this study is to develop an automated system for sealing cracks in pavement, and to validate the developed system through field trials. A machine vision algorithm, which is composed of noise elimination, crack network mapping and modeling, and path planning, was developed to operate the proposed automated system effectively. Extension of the algorithms and tools presented in the study to other applications is also recommended for future studies.