• 한국입자에어로졸학회지
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• 제15권2호
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• pp.67-78
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• 2019

Since existing measurement sites are required to construct a high-cost PM measuring device and a measuring site of a large area, there is a limit to the construction of a high-resolution measurement network. Therefore, it is necessary to develop a low-cost, high-performance PM measuring device (as an alternative technology) that can increase the resolution of PM measurement, and it is necessary to establish a base to provide real-time PM information for whole people. Therefore, in this study, the alternative technique (light scattering method) for achieving the above object was examined, performance evaluation was carried out, and it was verified that the light scattering method was usable. Various PM measurement results were compared and analyzed to find PM monitoring points and resolutions we would like to propose.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.137-140
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• 2008

Recently many areas require wide field of view images. Such as surveillance, virtual reality, navigation and 3D scene reconstruction. Conventional camera systems have a limited filed of view and provide partial information about the scene. however, omni directional vision system can overcome these disadvantages. Acquiring 360 degree panorama images requires expensive omni camera lens. In this study, 360 degree panorama image was tested using a low cost optical reflector which captures 360 degree panoramic views with single shot. This 360 degree panorama image system can be used with detailed positional information from GPS/INS. Through this study result, we show 360 degree panorama image is very effective tool for mobile monitoring system.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.58-65
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• 2011

Construction Productivity is one of the most important elements in construction management. It is used in construction process scheduling and cost management, which are significant sector in construction management. It is important to make appropriate schedule and monitor how works are done within schedule. But construction project contains uncertainty and inexactitude, modifying construction schedule is being an issue to manage construction works well. Even though prediction and monitoring of productivity can be principal activity, it is hard to predict productivity with manager's experience and a standard of estimate. A large number of factors influencing productivity, such as drawing, construction method, weather, labor, material, equipment, etc. But current calculation of productivity depends on empirical probability, not consider difference of each influencing factor. In this research, the aim is to present a productivity predicting regression model of form work, which includes effectiveness of influences factors. 5 variables existed inside form work are selected by interview and site research based on literature review of existed various productivity influencing factors. The effectiveness and correlation of productivity influencing factors are analyzed by statistical approach, and it is used to make productivity regression model. The finding of this research will improves monitoring and controlling of project schedule in construction phase.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6550-6557
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• 2013

공공 도로건설사업은 국토교통부 소속기관 중 하나인 지방국토관리청에서 발주되며 각 건설현장은 공사관리관을 두어 관리하고 있다. 공사관리관은 다수의 공사현장을 수시로 방문하여 현장을 점검 감독함에 따라 현장까지 이동하는데 많은 시간과 비용이 소요됨으로 현장관리 업무의 효율화가 요구되고 있다. 이에 공사관리관의 업무효율성 제고를 위해 현장방문을 최소화하고, 원격지에서 공사 진척현황을 실시간으로 모니터링 할 수 있도록 현장모니터링 관리 체계의 도입이 필요하다. 본 연구에서는 공공 도로건설공사를 대상으로 웹카메라(Web camera)를 활용한 원격 현장모니터링시스템을 구축하였다. 또한 10개 건설현장을 선정하여 시범적용을 실시하고, 효과분석을 통해 적용성을 검증하였다. 적용성 검증 결과, 웹카메라를 활용한 원격 현장관리는 기존 현장관리 방식에 비해 약 35% 정도의 비용절감효과를 갖는 것으로 분석되었다. 마지막으로 현장모니터링 관리 체계의 적용을 위한 가이드라인 마련과 도입방안을 검토하고, 개선방안을 제시하였으며, 이를 통해 불필요한 현장방문을 최소화하고, 현장의 취약지점에 대한 위험요소를 사전에 차단하여 각종 재난 및 재해를 사전에 예방할 수 있도록 하였다. 아울러 안전사고 예방과 부실시공의 근절을 통한 시설물의 품질을 향상시키리라 기대된다.

• Journal of Construction Engineering and Project Management
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• 제6권2호
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• pp.24-29
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• 2016

This paper elaborates the significance of scenario planning in risk management, and presents an integrated approach which takes into account the 'Risk Events' derived from scenario planning for risk prioritisation. This research integrates scenario planning with Risk Failure Mode and Effect Analysis (RFMEA) through examples from construction litigations of project schedule and cost overrun cases as a simplified approach to project risk management. The proposed methodology incorporates scenarios developed from realistic events of dispute and arbitration cases from construction projects, and thereby increasing potential to foresee risks and their effects well in advance. The results from this methodology shall be validated against outcome of survey study conducted by KPMG-PMI (2013) on project schedule and cost overruns that was based on Ministry of Statistics and Programme Implementation (MoSPI) Project Monitoring data for 2012-13.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.116-119
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• 2004

The existing monitoring and control systems of utility-pipe conduit (power tunnel, cable tunnel etc) have established communication lines using optical fiber, leaky coaxial cable (LCX), and several kinds of control cable. Due to the properties of the used media, the cost of equipment is considerably high and the maintenance of the system is difficult. Also, the term of carrying out is long so that the extension of the system is in difficulty. Now it is desirable to adopt Power Line Communication (hereinafter, PLC) technology in the monitoring and control systems and use the existing low-voltage power-line for lamplight as communication line. This will lead the reduction of the construction cost and the easy maintenance of the system. In this paper, we research the characteristics of PLC in conduit, design and manufacture the field test system, and analyze the performance of the system by field test. Then, we introduce the reliable monitoring and control system of utility-pipe conduit using PLC.

• Safety and Health at Work
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• 제10권4호
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• pp.452-460
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• 2019

Background: Monitoring and control of PM_2.5 are being recognized as key to address health issues attributed to PM_2.5. Availability of low-cost PM_2.5 sensors made it possible to introduce a number of portable PM_2.5 monitors based on light scattering to the consumer market at an affordable price. Accuracy of light scatteringe-based PM_2.5 monitors significantly depends on the method of calibration. Static calibration curve is used as the most popular calibration method for low-cost PM_2.5 sensors particularly because of ease of application. Drawback in this approach is, however, the lack of accuracy. Methods: This study discussed the calibration of a low-cost PM_2.5-monitoring device (PMD) to improve the accuracy and reliability for practical use. The proposed method is based on construction of the PM_2.5 sensor network using Message Queuing Telemetry Transport (MQTT) protocol and web query of reference measurement data available at government-authorized PM monitoring station (GAMS) in the republic of Korea. Four machine learning (ML) algorithms such as support vector machine, k-nearest neighbors, random forest, and extreme gradient boosting were used as regression models to calibrate the PMD measurements of PM_2.5. Performance of each ML algorithm was evaluated using stratified K-fold cross-validation, and a linear regression model was used as a reference. Results: Based on the performance of ML algorithms used, regression of the output of the PMD to PM_2.5 concentrations data available from the GAMS through web query was effective. The extreme gradient boosting algorithm showed the best performance with a mean coefficient of determination (R²) of 0.78 and standard error of 5.0 ㎍/㎥, corresponding to 8% increase in R² and 12% decrease in root mean square error in comparison with the linear regression model. Minimum 100 hours of calibration period was found required to calibrate the PMD to its full capacity. Calibration method proposed poses a limitation on the location of the PMD being in the vicinity of the GAMS. As the number of the PMD participating in the sensor network increases, however, calibrated PMDs can be used as reference devices to nearby PMDs that require calibration, forming a calibration chain through MQTT protocol. Conclusions: Calibration of a low-cost PMD, which is based on construction of PM_2.5 sensor network using MQTT protocol and web query of reference measurement data available at a GAMS, significantly improves the accuracy and reliability of a PMD, thereby making practical use of the low-cost PMD possible.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.426-431
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• 2011

The quality of performance evaluation on engineering consultants that provide design-related technical services is difficult to be measured, and only a handful of papers discussed the quality during the design stage. Although design cost is relatively far less than construction cost for a project, the decisions made in the design phase have a significant impact on the final products of the project, especially for large public construction projects. Therefore, this research focuses on reviewing and then establishing a performance evaluation framework for the consulting firms that execute detailed design and provide technical services for the Taipei Rapid Transit Systems (TRTS). By interviewing experts, this study first established a set of indicators to evaluate these firms' performance. Then, those indicators were incorporated into the four aspects of balanced scorecard (BSC) to establish the architecture of the evaluation mechanism. The weight of each indicator was calculated by analytic hierarchy process (AHP) from a survey conducted among experts. The results showed that the top-three indicators were quantity take-off, functions conformity, and budgeting. The framework of performance evaluation established by this study can be applied to measure service performance during the design stage. It not only facilitates the monitoring of consulting firms, but also helps to reduce unnecessary change orders and disputes during the construction stage.

• Advances in Energy Research
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• 제7권2호
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• pp.123-134
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• 2020

Photovoltaic systems are progressively attached importance and their installed capacity increases day by day because of their reliability, decremented installation and operating cost and simple construction structure. Generated power obtained from a photovoltaic system changes depending upon regional distinctness, and It can be estimated approximately by taking into consideration mean global radiation amount, temperature and humidity. However, there may be different regional negative or positive factors like dust, air pollution, desert powder which affect generated power. The best reliable data for a region can be obtained from the existing photovoltaic system in the region. For this purpose, a monitoring system for 1000W monocrystalline photovoltaic system constructed at Kocaeli University Uzunciftlik Nuh Cimento Vocational High Scholl is prepared. The installed monitoring system shows and records real values generated from the photovoltaic system and environmental data. In the study, Instantaneous data obtained from the monitoring system for October 2018 and 7th October 2018 is given within figures. Additionally, daily and monthly total energy productions of the photovoltaic system are given for October 2018 and date interval between July 2018 and March 2018, respectively.

• Ocean and Polar Research
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• 제25권4호
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• pp.593-601
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• 2003

The purpose of this paper is to investigate economic feasibility of creating artificial tidal flats using cost-benefit analyses. We assumed that the cost factors are associated with designing, construction and monitoring, and the benefit factors are associated with fisheries production, habitation, prevention of disasters, water purification, aesthetic value and existence value. First, for analyzing economic feasibility, the scenario suggests that a design can be made in a year, construction can be completed in three years and monitoring must be made for 20 years. Assuming the discount rate of 7.5%, economic feasibility analyses showed that B/C was 2.26 and IRR was 14.50. This study indicated there is economic validity of implementing creation of artificial tidal flat. In addition, we carried out a sensitivity analysis at the change of discount rate and restoration rate. The result of sensitivity analysis clearly showed that economic validity is low when discount rate is over 15%, and changes in restoration rate did not significantly effect on the economic validity.