• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.921-934
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• 2014

The purpose of the study is to derive a long term reservoir operation method that is easy to understand and apply to practical use for dam operators. The zone based operation rule is a simple method to make operation decisions by criteria corresponding to storage zones. The reservoir storage levels dividing a reservoir, however, must be determined by some methods. We developed a reservoir operation model based on the zone based operation rule and the shuffled complex evolution algorithm (SCE-UA) was used to determine storage levels for zone division. The model was applied to Angat Dam in the Philippines that has trouble in water supply due to imbalance between supply and demand. We derived a zone based operation rule for Angat Dam and applied it to the reservoir simulation of Angat Dam using the historical inflow. The simulation results showed water supply deficit and power generation were improved by 34.5% and 21.2%, respectively, when compared with the historical records. The current study results may be used to derive a long term reservoir operation rule.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.67-81
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• 1998

An Automated Guided Vehicle System (AGVS) with a unidirectional loop guide path is modeled as a discrete-time stationary Markov chain. It is discussed how to estimate the mean response time, the utilization, and the cycle time of AGV for a delivery order. Three common operation strategies for idle vehicles - central zone positioning rule, circulatory loop positioning rule and point of release positioning rule - are analyzed. These different operation strategies are compared with each other based on the performance measures.

• Journal of the Korea Safety Management & Science
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• v.3 no.3
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• pp.97-106
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• 2001

This paper considers automated storage and retrieval systems with double shuttle. We developed the expected travel time model based on the first come first served rule. An heuristic procedure by retrieval order sequencing was presented which aimed to improve the operation efficiency laking advantage of ＂No cost zone＂. Through sensitivity study, we evaluated the performance of the double shuttle system working on the four command cycle.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.376-383
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• 2006

In this paper, autonomous information exchange methodology is studied between IEDs using SOAP protocol based on XML and PtP communication to archive the safety and reliability of large-scale system operation. The SOAP protocol has the advantages in the independency Problem for operating systems, using language, platforms and the security problem because it is XML-based RPC protocol. Inference-based solution of the IED is designed as rule-based solution so that the IED internal status, the system status or the faulted zone can be inferred autonomously using the internal data as well as information data obtained from free information exchange among other IEDS, Also, it is designed so that the inference results and the operation information are transmitted to the above SCADA system, and determined autonomously whether the commands from the SCADA are executed or not. Finally, The inference-based solution of IED and information exchange system among IEDS is implemented using MS Visual C++ MFC, MS SOAP and MS XML. Availability and accuracy of the proposed methodology and the design is verified from diversity simulation reviews for typical distribution substation.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.419-425
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• 2020

There are many accident risks in logging operation of forestry such as struck by felled trees and caught in, under, or between felled trees. These accidents are primarily occurred by not keeping a safe distance between workers. According to the forestry safety instruction, workers are not supposed to go into the safety zone which is a circle with a radius of more 2 times the height of felling tree. However, this rule does not keep because of poor safety consciousness, poor sight and extreme noise of logging operation machines. This problem causes many major accidents every year. To solve this problem, we made forestry safety helmets based on IoT technology. These helmets have functions to make a visual and an acoustic alarm signal when reach the distance between workers within 20 meters. We developed the algorithm to operate the helmet's functions and conducted tests to check the functions. As a result of tests, we assured the normal system operating conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.206-206
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• 2021

The necessity for appropriate management of water resources infrastructures such as reservoirs, levees, and dikes is increasing due to unexpected hydro-climate irregularities and rising water demands. To meet this need, past studies have focused on advancing theoretical optimization algorithms such as nonlinear programming, dynamic programming (DP), and genetic programming. Yet, the optimally derived theoretical solutions are limited to be directly implemented in making release decisions in the real-world systems for a variety of reasons. This study first aims to comparatively analyze the two prominent optimization methods, DP and evolutionary multi-objective direct policy search (EMODPS), under historical inflow series using K-fold cross validation. A total of six optimization models are formed each with a specific formulation. Then, one of the optimization models was coupled with the actual zone-based hedging rule that has been adopted in practice. The proposed methodology was applied to Boryeong Dam located in South Korea with conflicting objectives between supply and demand. As a result, the EMODPS models demonstrated a better performance than the DP models in terms of proximity to the ideal. Moreover, the incorporation of the real-world policy with the optimal solutions improved in all indices in terms of the supply side, while widening the range of the trade-off between frequency and magnitude measured in the sides of demand. The results from this study once again highlight the necessity of closing the gap between the theoretical solutions with the real-world implementable policies.