• Journal of the Korean Geotechnical Society
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• v.26 no.3
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• pp.59-68
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• 2010

Systematic risk management is necessary in grand scaled urban construction because of the existence of complicated and various risk factors. Problems of obstructions, adjacent structures, safety, environment, traffic and geotechnical properties need to be solved because urban construction is progressed in limited space not as general earthwork. Therefore the establishment of special risk management system is necessary to manage not only geotechnical properties but also social and cultural uncertainties. This research presents the technique analysis by the current state of risk management technique. Risk factors were noticed and the importance of each factor was estimated through survey. The systemically categorized database was established. Risk extraction module, matrix and score module were developed based on the database. Expected construction budget and time distribution can be computed by Monte Carlo analysis of probabilities and influences. Construction budgets and time distributions of before and after response can be compared and analyzed 80 the risks are manageable for entire whole construction time. This system will be the foundation of standardization and integration. Procurement, efficiency improvement, effective time and resource management are available through integrated management technique development and application. Conclusively decrease in cost and time is expected by systemization of project management.

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.1
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• pp.47-54
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• 2023

Purpose PET-CT imaging require an appropriate quality assurance system to achieve high efficiency and reliability. Quality control is essential for improving the quality of care and patient safety. Currently, there are performance evaluation methods of UN2-1994 and UN2-2001 proposed by NEMA and IEC for PET-CT image evaluation. In this study, we compare phantom images with the same experiments before and after PET-CT 3D normalization and well counter correction and evaluate the usefulness of quality control. Materials and methods Discovery 690 (General Electric Healthcare, USA) PET-CT equiptment was used to perform 3D normalization and well counter correction as recommended by GE Healthcare. Based on the recovery coefficients for the six spheres of the NEMA IEC Body Phantom recommended by the EARL. 20kBq/㎖ of ¹⁸F was injected into the sphere of the phantom and 2kBq/㎖ of ¹⁸F was injected into the body of phantom. PET-CT scan was performed with a radioacitivity ratio of 10:1. Images were reconstructed by appliying TOF+PSF+TOF, OSEM+PSF, OSEM and Gaussian filter 4.0, 4.5, 5.0, 5.5, 6.0, 6,5 mm with matrix size 128×128, slice thickness 3.75 mm, iteration 2, subset 16 conditions. The PET image was attenuation corrected using the CT images and analyzed using software program AW 4.7 (General Electric Healthcare, USA). The ROI was set to fit 6 spheres in the CT image, RC (Recovery Coefficient) was measured after fusion of PET and CT. Statistical analysis was performed wilcoxon signed rank test using R. Results Overall, after the quality control items were performed, the recovery coefficient of the phantom image increased and measured. Recovery coefficient according to the image reconstruction increased in the order TOF+PSF, TOF, OSEM+PSF, before and after quality control, RCmax increased by OSEM 0.13, OSEM+PSF 0.16, TOF 0.16, TOF+PSF 0.15 and RCmean increased by OSEM 0.09, OSEM+PSF 0.09, TOF 0.106, TOF+PSF 0.10. Both groups showed a statistically significant difference in Wilcoxon signed rank test results (P value<0.001). Conclusion PET-CT system require quality assurance to achieve high efficiency and reliability. Standardized intervals and procedures should be followed for quality control. We hope that this study will be a good opportunity to think about the importance of quality control in PET-CT

• Design Convergence Study
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• v.16 no.3
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• pp.103-118
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• 2017

It is expected that the integrated control service of the public sector will be increased for the safety of citizens in the future. Therefore, In this study, we analyzed the classification of CCTV control center and the characteristics of interior design. The survey was conducted at eight control centers in Seoul that were constructed since 2007 and analyzed according to the criteria of general matters, services, spatial basic information, spatial structure, and internal structure. The results of the survey are summarized as follows. Based on the results of the study, the Integrated Control Center is a space where the ratio of the physical environment is not high but performs important tasks for the citizens of the city, which are operated 24 hours a day, and security and security. It is characterized by the efficient space allocation for the treatment, the design of the moving line, and the connection according to the urgent work flow. The results of this study are expected to be used as basic data for other integrated control center environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.485-492
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• 2023

Among the methods to improve traffic congestion by providing real-time traffic information and solving problems like traffic congestion and traffic crashes, private enterprise is implementing policies to lower insurance premiums like compensation for drivers' driving safety scores. Despite the emergence of various incentive policies, a study on the level of incentive payment for safe/eco-friendly driving is insufficient. The research analyzed the satisfactory factors that affect the scale of incentives through questionnaires and the applicable scale of incentives that enable safe/eco-friendly driving using a binary logistic regression model. As a result of analyzing the incentive scale of the appropriate payment amount for each driving score increase, 0.4% of the toll fee was derived when the driving score increased by 20 points, and 0.5% of the toll fee was derived when the driving score increased by 30 points. This study on calculating the appropriate incentive payment scale for driver information sharing and driving score increase will help optimize incentives and prepare system implementation plans.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.395-401
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• 2009

One of the key design factors for the ventilation and safety system at extra long tunnel is the airflow velocity induced by the natural ventilation force. Despite of the importance, it has not been widely studied due to the complicated influencing variables and the relationship among them is difficult to quantify. At this moment none of the countries in the world defines its specific value on verified ground. It is also the case in Korea. The recent worldwide disasters by tunnel fires and demands for better air quality inside tunnel by users require the optimization of the tunnel ventilation system. This indicates why the natural ventilation force is necessary to be thoroughly studied. This paper aims at predicting the natural ventilation force at a 11 km-long tunnel which is in the stage of detailed design and will be the longest vehicle tunnel in Korea. The concept of barometric barrier which can provide the maximum possible natural ventilation force generated by the topographic effect on the external wind is applied to estimate the effect of wind pressure and the chimney effect caused by the in and outside temperature difference is also analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.211-219
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• 2010

The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.

• Maritime Security
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• v.6 no.1
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• pp.37-56
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• 2023

Recently, with the rapid development of ICT(Information and Communication Technology) and AI(Artificial Intelligence) technology industries, the emergence of MASS(Maritime Autonomous Surface Ship), which were thought only in the distant future, is approaching a reality. Along with the development of these amazing technologies, changes in the private law sector, such as liability, compensation for damages, and maritime insurance, as well as in the public law sector, such as maritime safety, marine environment protection, and maintenance of maritime order, have become necessary in the field of maritime law. In particular, with the advent of a new type of ship called MASS that does not have a crew on board, the kind and type of liability, compensation for damages, and insurance contracts in the event of a marine accident will also change. In this paper, the general theory about concept, classification, effectiveness and future of MASS and the general theory about concept and various obligations and responsibilities under the maritime law for discussion of MASS are reviewed. Next, in addition, regarding the problems that may occur in the event of a marine accident from MASS, the status as a ship, the legal relationship of the chartering contract, obligation to exercise due diligence in making the vessel seaworthiness, subject of responsibility, and liability for damages and immunity are reviewed from the perspective of maritime law. In addition, in the degree four of MASS, the necessities of further research to clarify the attributable subjects and standards of responsibility in the event of a marine accident, as well as the necessities of institutional improvement such as technology development, enactment and amendment of law and funding are presented.

• The Journal of Bigdata
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• v.6 no.2
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• pp.151-159
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• 2021

Construction of a blockchain network needs a cumbersome and time consuming activity. To overcome these limitations, global IT companies such as Microsoft are providing cloud-based blockchain services. In this paper, we propose a blockchain-based construction and management tool that enables blockchain developers, blockchain operators, and enterprises to deploy blockchain more comfortably in their infrastructure. This tool is implemented using Hyperledger Fabric, one of the famous private blockchain platforms, and Ansible, an open-source IT automation engine that supports network-wide deployment. Instead of complex and repetitive text commands, the tool provides a user-friendly web dashboard interface that allows users to seamlessly set up, deploy and interact with a blockchain network. With this proposed solution, blockchain developers, operators, and blockchain researchers can more easily build blockchain infrastructure, saving time and cost. To verify the usefulness and convenience of the proposed tool, a blockchain network that conducts electronic voting was built and tested. The construction of a blockchain network, which consists of writing more than 10 setting files and executing commands over hundreds of lines, can be replaced with simple input and click operations in the graphical user interface, saving user convenience and time. The proposed blockchain tool will be used to build trust data infrastructure in various fields such as food safety supply chain construction in the future.

• The Journal of Bigdata
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• v.7 no.1
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• pp.15-27
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• 2022

In the past five years, the fatality rate of single-vehicle accidents has been 4.7 times higher than that of all accidents, so it is necessary to establish a system that can detect and respond to single-vehicle accidents immediately. The IoT(Internet of Thing)-based real-time traffic accident recognition system proposed in this study is as following. By attaching an IoT sensor which detects the impact and vehicle ingress to the guardrail, when an impact occurs to the guardrail, the image of the accident site is analyzed through artificial intelligence technology and transmitted to a rescue organization to perform quick rescue operations to damage minimization. An IoT sensor module that recognizes vehicles entering the monitoring area and detects the impact of a guardrail and an AI-based object detection module based on vehicle image data learning were implemented. In addition, a monitoring and operation module that imanages sensor information and image data in integrate was also implemented. For the validation of the system, it was confirmed that the target values were all met by measuring the shock detection transmission speed, the object detection accuracy of vehicles and people, and the sensor failure detection accuracy. In the future, we plan to apply it to actual roads to verify the validity using real data and to commercialize it. This system will contribute to improving road safety.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.633-640
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• 2023

In this study, numerical analysis was performed based on field investigation to derive an appropriate reinforcement method by analyzing the displacement behavior characteristics of concrete blocks generated in the direct fixation track on the bridges of the serviced light rail transit. The track of this study was a direct fixation track on a sharp curved track, and the problem of movement of the concrete blocks installed on the bridge deck in the longitudinal and lateral directions occurred. In this study, based on the finite element model using 3D solid elements, the behavior of the direct fixation track that could be occurred under operating load conditions was analyzed. In addition, the reinforcement effect of various reinforcement methods was analyzed. As a result of analyzing the lateral displacement before and after reinforcement, it was analyzed that the maximum lateral displacement after reinforcement under the extreme lateral wheel loads significantly decreased to about 3% (about 0.1mm) compared to before reinforcement. In addition, as a result of examining the generated stress of the filling mortar, bridge decks, and reinforcing bar, it was analyzed that all of them secured a sufficient safety factor of 2.6 or higher, and the optimal conditions for the reinforcement method were derived. Therefore, it is judged that the number of anchoring reinforcements and symmetrical anchor placement reviewed in this study will be effective in controlling the occurrence of lateral displacement of concrete blocks and securing the structural integrity of bridges and concrete blocks.