• The Journal of Bigdata
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• v.7 no.1
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• pp.99-111
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• 2022

A simulation technique can be used to analyze performance measures and support decision makings in manufacturing systems considering operational uncertainty and complexity. The simulation requires an input modeling procedure to reflect the target system's characteristics. However, data collection to build a simulation is quite limited when a target system includes manual productions with a lot of operational time such as construction equipment assembly lines. This study proposes a procedure for simulation input modeling using video data when it is difficult to collect enough input data to fit a probability distribution. We conducted a video-data analysis and specify input distributions for the simulation. Based on the proposed procedure, simulation experiments were conducted to evaluate key performance measures of the target system. We also expect that the proposed procedure may help simulation-based decision makings when obtaining input data for a simulation modeling is quite challenging.

• Journal of Korea Water Resources Association
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• v.57 no.4
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• pp.249-261
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• 2024

Climate change has intensified the severity of extreme floods, presenting substantial challenges to dam management and operation. Traditionally, flood control strategies for dam operations have been based on theoretical scenarios, such as designed floods, without taking into account downstream conditions. However, in practice, managing floods involves operating dams based on climate forecasts. This strategy encounters challenges due to the limited predictability of climate forecasts, which in turn leads to uncertainty in decisionmaking among dam managers. This study proposes a flood control approach for dam operations that involves gradually increasing the outflow, considering the operational constraints and potential downstream damage, based on inflow data. The effectiveness of this method was assessed through simulation, employing both a designed flood and data from the most significant historical flood. The dam operation strategy for flood control presented in this study provides a framework for dam operators, facilitating consistent decisionmaking in flood management by integrating realistic dam operational conditions.

• Asia pacific journal of information systems
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• v.13 no.4
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• pp.257-277
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• 2003

Recently, organizations intend to adopt new information technology for acquiring relative advantages in competitive business environment. Especially, many companies have paid attention to web-based electronic commerce. But research in this area has largely been performed to the operational and technical aspects of web site. Also the World Wide Web(web) has become one of the most widely used information technologies, but research indicates that there are many firm that are still considering whether to establish a web presence. This study examines factors influencing adoption of corporate web site over time. To examine why companies adopt web site, this study regards web site as an innovation and finds out these reason through Innovation Diffusion Theory. Independent variables of this research are composed of innovation characteristics, organizational characteristics and environmental characteristics. By the result of logistic regression analysis, we find that there are significant differences between early adopters and late adopters of web site for three adoption factors : top management support, organization size, environmental uncertainty. These findings confirm the theoretical frame for adoption of corporate web site. Also this study will provide good guidelines to the companies and the vendors in shaping the strategies of IT adoption and IT diffusion respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.526-535
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• 2016

In this study, the estimating weight data of eight leading ships of Korea navy were processed by comparing with the final weight data of their incline test results statistically, and are analyzed as follows; The maximum criteria of the weight margins of Korea naval ship in the preliminary and detailed design phases seem to be appropriate values, but the minimum criteria would be advisable to update more reasonable values. And, the limitation that the acceptable deviation of lightship weight should be 10 % of the lightship weight on a naval ship's ROC(Required Operational Capabilities) is recommended to be prohibited, because it comes from the weight estimation which has considerable uncertainty and it may also drop off design flexibility. Finally, the SWBS(Ship Work Breakdown System) groups which have larger deviation values in the estimating weight of naval ships are necessary to improve their accuracies, and to upgrade their weight database continuously.

• Environmental Engineering Research
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• v.20 no.3
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• pp.268-276
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• 2015

Solid waste production increases due to population and consumption increments. Landfill is the ultimate destination for all kinds of municipal solid waste; and is the most convenient waste disposal method in developing countries. To minimize investment and operational costs and society's opposition towards locating landfills nearby, proper landfill sizing and siting are essential. In this study, solid waste forecasting using Autoregressive Integrating Moving Average (ARIMA) was integrated with government future plans and waste composition to estimate the required landfill area for the state of Selangor, Malaysia. Landfill siting criteria were then prioritized based on expert's preferences. To minimize ambiguity and the uncertainty of the criteria prioritizing process, the expert's preferences were treated using integrated Median Ranked Sample Set (MRSS) and Analytic Hierarchy Process (AHP) models. The results show that the required landfill area is 342 hectares and the environmental criteria are the most important; with a priority equal to 48%.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.486-495
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• 2009

This paper proposes a new methodology on reliability evaluation of a power system including solar cell generators (SCG). The SCGs using renewable energy resource such as solar radiation(SR) should be modeled as multi-state operational model because the uncertainty of the resource supply may occur an effect as same as the forced outage of generator in viewpoint of adequacy reliability of system. While a two-state model is well suited for modeling conventional generators, a multi-state model is needed to model the SCGs due to the random variation of solar radiation. This makes the method of calculating reliability evaluation indices of the SCG different from the conventional generator. After identifying the typical pattern of the SR probability distribution function(pdf) from SR actual data, this paper describes modelling, methodology and details process for reliability evaluation of the solar cell generators integrated with power system. Two test results indicate the viability of the proposed method.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.525-534
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• 2016

The biological wastewater treatment plant, which uses microbial community to remove organic matter and nutrients in wastewater, is known as its nonlinear behavior and uncertainty to operate. Therefore, operation of the biological wastewater treatment process much depends on observation and knowledge of operators. The manual inspection of human operators is essential to manage the process properly, however, it is impossible to detect a fault promptly so that the process can be exposed to improper condition not securing safe effluent quality. Among various process faults, equipment malfunction is critical to maintain normal operational state. To detect equipment faults automatically, the dynamic time warping was tested using on-line oxidation-reduction potential (ORP) and dissolved oxygen (DO) profiles in a sequencing batch reactor (SBR), which is a type of wastewater treatment process. After one cycle profiles of ORP and DO were measured and stored, they were warped to the template profiles which were prepared already and the distance result, accumulated distance (D) values were calculated. If the D values were increased significantly, some kinds of faults could be detected and an alarm could be sent to the operator. By this way, it seems to be possible to make an early detecting of process faults.

• Structural Monitoring and Maintenance
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• v.3 no.1
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• pp.33-49
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• 2016

Structural Health Monitoring (SHM) has been attracting numerous research efforts around the world because it targets at monitoring structural conditions and performance to prevent catastrophic failure, and to provide quantitative data for engineers and infrastructure owners to design a reliable and economical asset management strategy. In the past decade, with supports from Australian Research Council (ARC), Cooperative Research Center for Infrastructure and Engineering Asset Management (CIEAM), CSIRO and industry partners, intensive research works have been conducted in the School of Civil, Environmental and Mining Engineering, University of Western Australia and Centre for Infrastructural Monitoring and Protection, Curtin University on various techniques of SHM. The researches include the development of hardware, software and various algorithms, such as various signal processing techniques for operational modal analysis, modal analysis toolbox, non-model based methods for assessing the shear connection in composite bridges and identifying the free spanning and supports conditions of pipelines, vibration based structural damage identification and model updating approaches considering uncertainty and noise effects, structural identification under moving loads, guided wave propagation technique for detecting debonding damage, and relative displacement sensors for SHM in composite and steel truss bridges. This paper aims at summarizing and reviewing the recent research advances on SHM of civil infrastructure in Western Australia.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.239-248
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• 2014

Most systems used in industrial sites, actually have non-linearity and uncertainty. Therefore there are a lot of difficulties in evaluating conditions of these systems. Generally, the quantitative analysis and expression are found hard because the general public cannot easily make an accurate interpretation on the systems. Thus development of a system that utilizes an expertise from skilled analysts is required. In this research, a real-time sensor signal conditioning system and Fuzzy-expert system have been separately set up into an inference algorithm. So that it ensures a fast, accurate, objective and quantitative operational condition value provided to the manager. Therefore, FE_AFCDM is suggested in this literature, as an effective system for diagnosing the problems related to the air compressor. It can quantify the uncertain and absurd condition to operate the air compressor facilities safely and financially.

• Korean Journal of Childcare and Education
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• v.16 no.2
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• pp.25-45
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• 2020

Objective: The purpose of this study is to explore daycare-center director's perceptons of recruitment and to understand how hire beginning teachers. Methods: One hundred twenty-five directors of daycare-centers in Seoul, Incheon, and Gyeonggi-do Province answered a questionnaire that was developed by researchers. The results were analyzed by frequency analysis, descriptive statistics and multiple response analysis through SPSS 18.0. Furthermore, 17 of the directors that participated in the study were given individual interviews by qualitative methods for research. Results: First, 56.8% of the directors felt difficulty to employ beginning teachers because of 'lack of information about them' and 'uncertainty of practice capability.' On the other hand, other directors of daycare-centers said that they hire them for 'high acceptance' and 'operational efficiency of the daycare-center.' Second, the main way to recruit teachers for daycare-centers is open recruitment, and through recommendations of acquaintances or through colleges in relevant fields. Professional talent and personal characteristics were important selection criteria for recruitment, and daycare-center directors used interviews, résumés, cover-letters, and demo classes for the hiring process. Primarily, most directors select candidates through résumés and cover-letters, and the final selection is completed by conducting interviews. Conclusion/Implications: In conclusion, this study can be useful to prepare beginning teachers for employment and for educating applicants.