• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.229-234
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• 2012

Operator's action time is evaluated from MAAP4 analysis used in conventional probabilistic safety assessment(PSA) of a nuclear power plant. MAAP4 code which was developed for severe accident analysis is too conservative to perform a realistic PSA. A best-estimate code such as RELAP5/MOD3, MARS has been used to reduce the conservatism of thermal hydraulic analysis. In this study, operator's action time of core cooling recovery operation is evaluated by using the MARS code, which its Fussell-Vessely(F-V) value was evaluated as highly important in a small break loss of coolant(SBLOCA) event and loss of component cooling water(LOCCW) event in previous PSA. The main conclusions were elicited : (1) MARS analysis provides larger time window for operator's action time than MAAP4 analysis and gives the more realistic time window in PSA (2) Sufficient operator's action time can reduce human error probability and core damage frequency in PSA.

• Nuclear Engineering and Technology
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• v.29 no.5
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• pp.368-374
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• 1997

This paper presents a new approach to the evaluation of an accident management strategy when an operator action is involved. This approach classifies the failure in implementing a given strategy into 4 possible mechanisms, and provides their corresponding quantification methods : 1) the failure to formulate correct intention by operators, 2) the failure to take an adequate action following a correct diagnosis, 3) the failure of a system operation following an adequate action, and 4) the failure due to a delayed action. The proposed method was applied to assess a cavity flooding strategy that uses containment spray system (CSS), and the result shows that the method is more appropriate in evaluating accident management strategies when human action is involved.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.136-143
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• 2018

In this study, we conducted a pilot study on the multiple spurious operations (MSO) analysis in the fire probabilistic safety assessment (PSA) of domestic nuclear power plant (NPP) to identify the degree of influence of the operator actions used in the MSO mitigation strategies. The MSO scenario of the domestic reference NPP selected for this study is refueling water tank (RWT) drain down event. It could be caused by spurious operations of the containment spray system (CSS) of the reference NPP. The RWT drain down event can be stopped by the main control room (MCR) operator actions for stopping the operation of CSS pump or closing the CSS motor operated valve if the containment spray actuation signal (CSAS) is spuriously actuated. Outside the MCR, it can be stopped by operator actions for closing the CSS manual valves or motor operated valve or stopping the operation of CSS pump. The quantification result of a fire PSA model that takes into account all recovery actions for the RWT drain down event lead to risk reduction by about 95%, compared with quantification result of fire PSA model without considering them. Among the various operator actions, the recovery action for the spurious CSAS operations and the operator action for the manual valve are identified as the most important operator actions. This study quantitatively showed the extent to which the operator actions used as MSO countermeasures have affected the fire PSA quantification results. In addition, we can see the rank of importance among the operator recovery actions in quantitative terms.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.141-144
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• 2002

Acupuncture effect principle on meridians is what physical stimulation does on general physiology so that it gets into new equilibrium from the fallen function state of human body. However, it is generally accepted that western medicine has regarded the action passageway of various kinds stimulation as nerve fluids tissue or nerve-endocrine-immune system. These regard any action for all meridians as a response to the stimulation. These are not treatments for transmission of the energy. This paper compares the change of electric potential when operator's bio-energy is passed on and when is not. As a result of it, the effect of acupuncture is different when a operator's bio-energy is passed on to meridians and it isn't. Therefore, it means that the general acupuncture is more effective than the insulation one. Moreover, we could certify that there is close relation between an operator's energy transmission and acupuncture effect.

• Journal of the Korea Society for Simulation
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• v.9 no.1
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• pp.83-91
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• 2000

Vehicle simulators provide an effective and safe environment for training operators. Many vehicle simulators have been developed but only a few have reached the stage of widely available tools; these tools are usually expensive and run on workstations only We have developed a low-cost, PC-based excavator simulator for training operators. Currently the simulator is dedicated to operating the boom, Em, bucket, and driver's cabin for digging by the action of the operator on two joysticks. This paper presents the implementation of the excavator simulator and some implementation results.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1955-1962
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• 2017

Induction motors are a workhorse for the industry. The condition monitoring and fault analysis are the main concern for the engineers. The bearing is one of the vital segment of the induction machine and the condition of the whole machine is decided based on the condition of the bearing. In the present paper, the vibration signal of the bearing has been used for the analysis. The first line of action is to perform a statistical analysis of the vibration signal which gives trends in signal. To get the location of a fault in the bearing the second action is to develop an index based on Wavelet Packet Transform node energy named as Bearing Damage Index (BDI). Further, Teager-Kaiser Energy Operator (TKEO) has been calculated from higher index value to get the envelope and finally Power Spectral Density (PSD) has been applied to identify the fault frequencies. A performance index has also been developed to compare the usefulness of the proposed method with other existing methods. The result shows that the strong amplitude of fault characteristics and its side bands help to decide the type of fault present in the recorded signal obtained from the bearing.

• Nuclear Engineering and Technology
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• v.47 no.2
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• pp.187-195
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• 2015

Human-induced initiating events, also called Category B actions in human reliability analysis, are operator actions that may lead directly to initiating events. Most conventional probabilistic safety analyses typically assume that the frequency of initiating events also includes the probability of human-induced initiating events. However, some regulatory documents require Category B actions to be specifically analyzed and quantified in probabilistic safety analysis. An explicit modeling of Category B actions could also potentially lead to important insights into human performance in terms of safety. However, there is no standard procedure to identify Category B actions. This paper describes a systematic procedure to identify Category B actions for low power and shutdown conditions. The procedure includes several steps to determine operator actions that may lead to initiating events in the low power and shutdown stages. These steps are the selection of initiating events, the selection of systems or components, the screening of unlikely operating actions, and the quantification of initiating events. The procedure also provides the detailed instruction for each step, such as operator's action, information required, screening rules, and the outputs. Finally, the applicability of the suggested approach is also investigated by application to a plant example.

• Journal of the Korean Society of Safety
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• v.7 no.4
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• pp.95-99
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• 1992

The attraction of using expert system in operator support systems for modern plant is that it offers a way of dealing with the problem of information overload that can occur during a severe disturbance at a modern industrial plant. During such a disturance the volume of information presented to operators may be such that they are unable to decide quickly what is important and what is not. Therefore, arriving at a correct diagnosis of the initialling fault may be delayed. An expert system operator sup-port system is a means of focusing attention on what really matters and cutting out the rest. This paper presents the development of prototype expert system which detect the fault part, machine, system and decide action priority. This prototype expert system has 6 sub- system which is Interface Manager, Decision Maker, Inference Engine, Knowledge base, Simulatio, and D.P System ( Diagnosis and predictor)

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.207-208
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• 1998

Classification of extracellularly recorded action potential into each unit is an important procedure for further analysis of spike trains as point process. We utilize feedforward neural network structures, multilayer perceptron and radial basis function network to implement spike classifier. For the efficient training of classifiers, nonlinear energy operator that can trace the instantaneous frequency as well as the amplitude of the input signal is used. Trained classifiers shows successful operation, up to 90% correct classification was possible under 1.2 of signal-to-noise ratio.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.7
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• pp.1894-1915
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• 2023

Software-Defined Networking (SDN) offers several advantages in dynamic routing, flexible programmable control and custom application-driven network management. However, the programmability of the data plane in traditional SDN is limited. A network operator cannot change the ability of the data plane and perform complex packet processing on the data plane, which limits the flexibility and extendibility of SDN. In the paper, AP-SDN (Action Program enabled Software-Defined Networking) architecture is proposed, which extends the action set of SDN data plane. In the proposed architecture, a modified Open vSwitch is utilized in the data plane allowing the execution of action programs at runtime, thus enabling complex packet processing. An example action program is also implemented which transparently encrypts traffic for terminals. At last, a prototype system of AP-SDN is developed and experiments show its effectiveness and performance.