• Safety and Health at Work
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• v.14 no.1
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• pp.10-16
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• 2023

Whilst Ecological momentary assessment (EMA) can provide important insights over time and across contexts among rotation workers whose work periods alternate with leave at home, it can also be challenging to implement in the resources and construction sectors. This review aimed to provide a summary of the methodological characteristics of EMA studies assessing health outcomes and related behaviors in rotation workers. Systematic searches in PubMed, Medline, EMBASE, CINAHL, PsycINFO, and Scopus were done to include 23 studies using EMA methods in assessing health-related outcomes and behaviors. EMA designs included daily diary: assessments once per day typically fixed at the end of day (47.8%), within day fixed interval time-based design: assessments on multiple times per day at certain times of day (17.4%) and combination of both designs (34.8%). Studies employed paper and pencil diaries (73.9%) and one or more electronic methods (60.9%): wrist-worn actigraphy device (52.2%) and online-based diaries (26.1%) for data collection. Most of the studies (91.3%) did not report prompting -EMAs by schedule alerts or compliance. Daily diary and within day fixed interval dairies designs are common, with the increasing use of electronic EMA delivery techniques. It is unclear how well participants adhere to assessment schedules, as these are inadequately reported. Researchers should report compliance-related information.

• Journal of the Korean GEO-environmental Society
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• v.14 no.12
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• pp.61-69
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• 2013

As construction for road and train tunnel is increasing, various geotechnical conditions can be faced during the construction stage. Especially, if the tunnel is located in limestone area, the cavity is mostly to locate in tunnel planning location. One or some cavities which can be harmful for tunnel safety are predicted. Hence, this study was fulfilled to confirm the influence between tunnel and cavity using laboratory scale down model test and numerical analysis. The scale down model test was carried out to confirm the failure load of the model ground about the interval length of cavity and tunnel and to analyze behaviour characteristics of the model ground on the cavity shape. From the model test result, the failure load decrease in accordance with decreasing of interval length between cavity and tunnel within 0.5D. The numerical analyses were carried out for verification about scale down model test. From the numerical analysis result, tunnel safety decreases in the case of the interval between cavity and tunnel within 0.5D.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.218-223
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• 2009

During the process of excavation for substructures of buildings, precise and constant measurements of retaining wall displacement is crucial for construction to be complete and safe. Currently an inclinometer is used to measure displacement around the perimeter of an excavation site. The existing inclinometer system requires an instrument to be placed inside pre-bored holes for each measurement with an typical interval of two weeks. This makes it difficult to obtain continuous displacement data, especially during a critical time such as rainy season in summer. Also, the existing inclinometer is placed at certain distance away from the retaining wall system itself. Thus, exact measurement of retaining wall movement is compromised because of the distance between the retaining wall and the inclinometer. This paper presents the development of wireless inclinometer system for the displacement measurement of retaining walls by being attached directly to the retaining wall. The result of the application of the developed systems are provided with advanced ubiquitous sensor network (USN) system features. The USN technique incorporated into the system enables users to monitor movement data from wherever possible and convenient such as construction manager's office on site or any other places connected through internet. The research work presented in this paper will provide a basis to save construction time and cost by preventing safe-related unexpected delay of construction due to the failure or collapse of retaining walls.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.287-288
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• 2023

The inspection work at construction sites is one of the important supervisory tasks, which involves verifying that the building is being constructed by the numerical values specified in the design drawings. The conventional measuring method for inspection involves using tools or equipment such as rulers directly by the personnel at the site, and it is usually confirmed by vision. Therefore, this study proposes an model to measure numerical values on images of the construction site. Through the case study to measure the installation interval of jack supports, the proposed algorithm was verified the effiect and validity. The results of this study suggest that it can support inspection work even in the office, which may have been overlooked by on-site inspectors, and contribute to the digitization of inspection work at construction sites.

• The Korean Journal of Applied Statistics
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• v.20 no.2
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• pp.257-266
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• 2007

It is known that Agresti-Coull approach is an effective tool for the construction of confidence intervals for various problems related to binomial proportions. However, the Agrest-Coull approach often produces a conservative confidence interval. In this note, confidence intervals based on a Bayesian approach are proposed for a linear function of independent binomial proportions. It is shown that the Bayesian confidence interval slightly outperforms the confidence interval based on Agresti-Coull approach in average sense.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.9
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• pp.545-551
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• 2004

CBTC(Communication Based Train Control) System can improve train operation efficiency by realizing moving block system which makes a continuous train interval control in accordance with the position and speed of train. Adopting radio transmission to make a continuous detection of train position and transmit the control data from the ground to a train, CBTC needs dedicated train operation and control algorithm which should be quite different from the conventional track-circuit-based train control system. This paper provides a train operation display and control algorithm for CBTC system in making train interval control, train route control and train supervision. Signalling pattern diagram is devised to analyze the train interval control mechanism of moving block system, and interlocking logic is devised to represent the train route control mechanism of moving block system. For train supervision, train occupation status on railway are displayed by using the segment which virtually divide the whole railway. The proposed method has been successfully applied to the development of CBTC system for the standardized AGT(automatic guided transit) which is under construction now in Korea, and also can be applied to any other CBTC system.

• Structural Engineering and Mechanics
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• v.38 no.6
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• pp.733-751
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• 2011

In the present study, a new kind of multivariable Reissner-Mindlin plate elements with two kinds of variables based on B-spline wavelet on the interval (BSWI) is constructed to solve the static and vibration problems of a square Reissner-Mindlin plate, a skew Reissner-Mindlin plate, and a Reissner-Mindlin plate on an elastic foundation. Based on generalized variational principle, finite element formulations are derived from generalized potential energy functional. The two-dimensional tensor product BSWI is employed to form the shape functions and construct multivariable BSWI elements. The multivariable wavelet finite element method proposed here can improve the solving accuracy apparently because generalized stress and strain are interpolated separately. In addition, compared with commonly used Daubechies wavelet finite element method, BSWI has explicit expression and a very good approximation property which guarantee the satisfying results. The efficiency of the proposed multivariable Reissner-Mindlin plate elements are verified through some numerical examples in the end.

• Plant Journal
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• v.9 no.4
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• pp.37-42
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• 2013

Power plants have many components and equipment. It is difficult for operators to know the each equipment fails or what equipment fails. It is important to prevent failure in advance. Recently, outlook of maintenance tasks is changing from time based maintenance to condition based maintenance. In this study, we selected RCM-based maintenance intervals for coal handling equipment at coal power plant. For RCM analysis, we have made great progress in a maintenance task and interval. If we apply RCM analysis to the whole plant system, we can expect qualitative improvement and efficient operation of power plant system.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.38-50
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• 2018

Spatio-temporal load forecasting (STLF) is a foundation for building the prediction-based power map, which could be a useful tool for the visualization and tendency assessment of urban energy application. Constructing one point-forecasting model for each electricity cell in the geographic space is possible; however, it is unadvisable and insufficient, considering the aggregation features of electricity cells and uncertainties in input variables. This paper presents a new STLF method, with a data-driven framework consisting of 3 subroutines: multi-level clustering of cells considering their aggregation features, load regression for each category of cells based on SLS-SVRNs (sparse least squares support vector regression networks), and interval forecasting of spatio-temporal load with sampled blind number. Take some area in Pudong, Shanghai as the region of study. Results of multi-level clustering show that electricity cells in the same category are clustered in geographic space to some extent, which reveals the spatial aggregation feature of cells. For cellular load regression, a comparison has been made with 3 other forecasting methods, indicating the higher accuracy of the proposed method in point-forecasting of spatio-temporal load. Furthermore, results of interval load forecasting demonstrate that the proposed prediction-interval construction method can effectively convey the uncertainties in input variables.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.73-79
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• 2005

This paper, introduces a Stochastic Project Scheduling Simulation system (SPSS III) developed by the author to predict a project completion probability in a certain time. The system integrates deterministic CPM, probabilistic PERT, and stochastic Discrete Event Simulation (DES) scheduling methods into one system. It implements automated statistical analysis methods for computing the minimum number of simulation runs, the significance of the difference between independent simulations, and the confidence interval for the mean project duration as well as sensitivity analysis method in What-if analyzer component. The SPSS 111 gives the several benefits to researchers in that it (1) complements PERT and Monte Carlo simulation by using stochastic activity durations via a web based JAVA simulation over the Internet, (2) provides a way to model a project network having different probability distribution functions, (3) implements statistical analyses method which enable to produce a reliable prediction of the probability of completing a project in a specified time, and (4) allows researchers to compare the outcome of CPM, PERT and DES under different variability or skewness in the activity duration data.