• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.1
• /
• pp.107-116
• /
• 2022

Recently, research has been actively conducted on the technology of inspection facilities through image-based analysis assessment of human-inaccessible facilities. This research was conducted to study the conditions of deep learning-based imaging data on bridges and to develop an evaluation prototype program for bridges. To develop a deep learning-based bridge damage detection prototype, the Semantic Segmentation model, which enables damage detection and quantification among deep learning models, applied Mask-RCNN and constructed learning data 5,140 (including open-data) and labeling suitable for damage types. As a result of performance modeling verification, precision and reproduction rate analysis of concrete cracks, stripping/slapping, rebar exposure and paint stripping showed that the precision was 95.2 %, and the recall was 93.8 %. A 2^nd performance verification was performed on onsite data of crack concrete using damage rate of bridge members.

• Journal of Nutrition and Health
• /
• v.44 no.1
• /
• pp.49-60
• /
• 2011

This study was performed to develop a children's dietary life safety index required by the Special Act on Safety Management of Children's Dietary Life enacted in 2009. An analytical hierarchy process was used to obtain initial weights of dietary life safety evaluation indicators. The Delphi method was applied to develop the weights along with 98 food and nutrition professionals. Three representative policy indicators, nine strategy indicators, 11 main evaluation indicators, and 20 detailed evaluation indicators were selected for the children's dietary life safety assessment. Three policy indicators and nine strategy indicators were the following: children's food safety indicator (support level of children' safety, safety management level of children's favorite foods, and safety management level of institutional food service), children's nutrition safety indicator (management level of missing meals and obesity, nutrition management level of children's favorite foods, and nutrition management level of institutional food service), and children's perception and practice level indicator ("Dietary Life Law" perception level, perception, and practice level for dietary life safety management, perception, and practice level for nutrition management). Weights of 40%, 40%, and 20% were given for the three representative policy indicators. The relative importance of nine strategic indicators, which were determined by the Delphi method is as follows: For children’s food safety, support level of children's safety, safety management level of children's favorite foods, and safety management level of institutional food service were given weights of 12%, 9%, and 19%, respectively. For children's nutrition safety, the missing meals and obesity management level, nutrition management level of children's favorite foods, and the nutrition management level of institutional food service were given weights of 13%, 11%, and 16%, respectively. The "Dietary Life Law" perception level, perception and practice level of dietary life safety management, and perception and practice level of nutrition management were given weights of 4%, 7%, and 9%, respectively.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.11 no.1
• /
• pp.90-104
• /
• 2008

Laser scanning technology with high positional accuracy and high density will be widely applied to vast range of fields including geomatics. Especially, the development of laser scanning technology enabling long range information extraction is increasing its full use in civil engineering. This study taps into the strengths of a terrestrial laser scanning technique to develop a tunnel cross section management system that can be practically employed for determining the cross section of tunnels more promptly and accurately. Three dimensional data with high density were obtained in a prompt and accurate manner using a terrestrial laser scanner. Data processing was then conducted to promptly determine arbitrary cross sections at 0.1meter, 0.5meter and 1.0meter intervals. A laser scanning technique was also used to quickly and accurately calculate the overbreak and underbreak of both each cross section and the entire tunnel section. As the developed system utilizes vast amounts of data, it was possible to promptly determine the shape of arbitrary cross section and to calculate the overbreak and underbreak more accurately with higher area precision. It is expected, therefore, that the system will not only enable more efficient and cost effective tunnel drilling management and monitoring but also will provide a basis for future construction and management of tunnel cross section.

• Journal of Korean Society of Transportation
• /
• v.36 no.1
• /
• pp.38-50
• /
• 2018

Emerging automated driving environments will lead to a mixed traffic flow depending on the interaction between automated vehicles (AVs) and manually driven vehicles (MVs) because the market penetration rate (MPR) of AVs will gradually increase over time. Understanding the characteristics of mixed traffic conditions, and developing a method to control both AV and MV maneuverings smoothly is a backbone of the traffic management in the era of automated driving. To facilitate smooth vehicle interactions, the maneuvering of AVs should be properly determined by various traffic and road conditions, which motivates this study. This study investigated whether the aggressiveness of AV maneuvering, defined as automated driving aggressiveness (ADA), affect the performance of mixed traffic flow. VISSIM microscopic simulation experiments were conducted to derive proper ADAs for satisfying both the traffic safety and the operational efficiency. Traffic conflict rates and average travel speeds were used as indicators for the performance of safety and operations. While conducting simulations, level of service(LOS) and market penetration rate(MPR) of AVs were also taken into considerations. Results implies that an effective guideline to manage the ADA under various traffic and road conditions needs to be developed from the perspective of traffic operations to optimize traffic performances.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.7 s.349
• /
• pp.72-83
• /
• 2006

It is not a practical solution that the DDoS attacks or worm propagations are protected and responded within a domain itself because it clogs access of legitimate users to share communication lines beyond the boundary a domain. Especially, the DDoS attacks with spoofed source address or with bogus packets that the destination addresses are changed randomly but has the valid source address does not allow us to identify access of legitimate users. We propose a scheme of distributed network security management to protect access of legitimate users from the DDoS attacks exploiting randomly spoofed source IP addresses and sending the bogus packets. We assume that Internet is divided into multiple domains and there exists one or more domain security manager in each domain, which is responsible for identifying hosts within the domain. The domain security manager forwards information regarding identified suspicious attack flows to neighboring managers and then verifies the attack upon receiving return messages from the neighboring managers. Through the experiment on a test-bed, the proposed scheme was verified to be able to maintain high detection accuracy and to enhance the. normal packet survival rate.

• Journal of the Society of Disaster Information
• /
• v.15 no.4
• /
• pp.597-606
• /
• 2019

Purpose: This paper is for the improvement of the safety education system in the construction industry, which has become a great threat to domestic industrial safety. Among the industrial sectors, the accident rate and death rate in the construction industry are the highest, and measures for falls in the litigation work are needed. Method: The application of the Analytic Hierarchy Process(AHP) resulted in the following conclusions. Results: The management group of the construction industry was divided into a group of on-site workers. In addition, the practical education system was reviewed by analyzing differences in perceptions of safety education. The survey results of the two groups were analyzed through AHP by dividing the construction safety education system into three layers. Conclusion: The results showed that managers showed a great deal of importance, such as actual conditions for implementation related to education, while on-site workers indicated importance for items that were somewhat site-oriented compared to managers. In addition, the two groups did not place much weight on the effectiveness of AR and VR, which have been expanding into safety education recently.

• Journal of Internet Computing and Services
• /
• v.11 no.1
• /
• pp.35-48
• /
• 2010

For the next generation mobile communication system, diverse wireless network techniques such as beyond 3G LTE, WiMAX/WiBro, and next generation WLAN etc. are proceeding to the form integrated into the All-IP core network. According to this development, Beyond 3G integrated into heterogeneous wireless access technologies must support the vertical handover and network to be used of several radio networks. However, unified management of each network is demanded since it is individually serviced. Therefore, in order to solve this problem this study is introducing the theory of Common Radio Resource Management (CRRM) based on Generic Link Layer (GLL). This study designs the structure and functions to support the vertical handover and propose the vertical handover algorithm of which policy-based and MCDM are composed between LTE and WLAN systems using GLL and CRRM. Finally, simulation results are presented to show the improved performance over the data throughput, handover success rate and the system service cost.

• Journal of Environmental Impact Assessment
• /
• v.28 no.2
• /
• pp.141-151
• /
• 2019

Korea has passed the Act on the Integrated Control of Pollutant-Discharging Facilities in 2015, and the integrated environmental management under the BAT standard is underway. To summarize the nature of integrated environmental management, it is the regulation by the integration of the management of the multi-pollutant source and the technical standard of BATs. In general, in environmental economics, regulation-based on technical standards are known to be inefficient. This paper attempts to evaluate the efficiency of BAT standards from an economic point of view. A simple multi-pollutant model demonstrates that the inefficiency of the environmental tax with imperfect information in a single pollutant situation is amplified under multi-pollutant conditions. The simultaneous introduction of BAT and IPPC can be partially explained by this logic. It is also highlighted by the strengthening of BAT standards by EU, as a countermeasure to the potential deterioration of air quality caused by the change of effective environmental taxes accompanying the fuel and emission price changes.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.9
• /
• pp.57-66
• /
• 2009

In the preliminary investigation (Park et al., 2009), the use of compressional wave velocity and its measurement techniques were proposed as a new quality control measure for trackbed fills. The methodology follows exactly the same procedure as the density control, except the density being replaced by the compressional wave velocity involving consistently with resilient modulus of design stage. The specifications for the control also include field compaction water content of optimum moisture content ${\pm}2%$ as well as the compressional wave velocity. In this sequel paper, crosshole and resonant column tests were performed as well direct-arrival method and laboratory compressional wave measurements to verify the practical applicability of a methodology far the new quality control procedure based upon compressional wave velocity. The stress-modified crosshole results reasonably well agree with the direct-arrival values, and the resonant column test results also agree well with the field crosshole results. The compressional wave velocity turned out to be an excellent control measure for trackbed fills both in the theoretical and practical point of view.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.7
• /
• pp.80-86
• /
• 2019

As computer performance improves, research using deep learning are being actively carried out in various fields. Recently, deep learning technology has been applying to the safety evaluation for structures. In particular, the internal blades of a turbine structure requires experienced experts and considerable time to detect surface damages because of the difficulty of separation of the blades from the structure and the dark environmental condition. This study proposes a Faster R-CNN deep learning model that can detect surface damages on the internal blades, which is one of the primary elements of the turbine structure. The deep learning model was trained using image data with dent and punch damages. The image data was also expanded using image filtering and image data generator techniques. As a result, the deep learning model showed 96.1% accuracy, 95.3% recall, and 96% precision. The value of the recall means that the proposed deep learning model could not detect the blade damages for 4.7%. The performance of the proposed damage detection system can be further improved by collecting and extending damage images in various environments, and finally it can be applicable for turbine engine maintenance.