• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1861-1868
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• 2008

In this paper, Passive Telemerty RF Sensor System using Unscented Kalman Filter algorithm(UKF) is proposed. General Passive Telemerty RF Sensor System means that it should be "wireless", "implantable" and "batterless". Conventional Passive Telemerty RF Sensor System adopts Integrated Circuit type, but there are defects like complexity of structure and limit of large power consumption in some cases. In order to overcome these kinds of faults, Passive Telemetry RF Sensor System based on inductive coupling principle is proposed in this paper. Because passive components R, L, C have stray parameters in the range of high frequency such as about 200[KHz] used in this paper, Passive Telemetry RF Sensor System considering stray parameters has to be derived for accurate model identification. Proposed Passive Telemetry RF Sensor System is simple because it consists of R, L and C and measures the change of environment like pressure and humidity in the type of capacitive value. This system adopted UKF algorithm for estimation of this capacitive parameter included in nonlinear system like Passive Telemetry RF Sensor System. For the purpose of obtaining learning data pairs for UKF Algorithm, Phase Difference Detector and Amplitude Detector are proposed respectively which make it possible to get amplitude and phase between input and output voltage. Finally, it is verified that capacitive parameter of proposed Passive Telemetry RF Sensor System using UKF algorithm can be estimated in noisy environment efficiently.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2915-2923
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• 2022

There is an increasing interest in passive safety systems to minimize the need for operator intervention or external power sources in nuclear power plants. Because a passive system has a weak driving force, there is greater uncertainty in the performance compared with an active system. In previous studies, several methods have been suggested to evaluate passive system reliability, and many of them estimated the failure probability using thermal-hydraulic analyses and the Monte Carlo method. However, if the functional failure of a passive system is rare, it is difficult to estimate the failure probability using conventional methods owing to their high computational time. In this paper, a procedure for the application of the Chernoff bound to the evaluation of passive system reliability is proposed. A feasibility study of the procedure was conducted on a passive decay heat removal system of a micro modular reactor in its conceptual design phase, and it was demonstrated that the passive system reliability can be evaluated without performing a large number of thermal-hydraulic analyses or Monte Carlo simulations when the system has a small failure probability. Accordingly, the advantages and constraints of applying the Chernoff bound for passive system reliability evaluation are discussed in this paper.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.199-202
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• 2002

This paper is about the implementation of Passive RFID(Radio Frequency Identification) tag system using a capacitive method, and explains the design and circuit's structure of this system. Fundamentally the capacitive RFID tag system consists of a tag reader, a passive tag and a host computer. And then this paper shows the system's prototype which analyzes a specification, and suggests the passive RFID system as a new method which manufactures a low cost tag system easily

• Structural Engineering and Mechanics
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• v.37 no.4
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• pp.443-458
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• 2011

An extensive numerical investigation on the magnetorheological (MR) damper-based smart passive control system for mitigating vibration of stay cables under wind loads has been conducted. The smart passive system is incorporated with an electromagnetic induction (EMI) device for reducing complexity of the conventional MR damper based semi-active control system by eliminating an external power supply part and a feedback control part (i.e., sensors and controller). In this study, the control performance of the smart passive system has been evaluated by using a cable structure model extracted from a full-scale long stay cable with high tension. Numerical simulation results of the proposed smart damping system are compared with those of the passive and semi-active control systems employing MR dampers. It is demonstrated from the results that the control performance of the smart passive control system is better than those of the passive control cases and comparable to those of the semi-active control systems in the forced vibration analysis as well as the free vibration analysis, even though there is no external power source in the smart passive system.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1431-1441
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• 2017

The Fukushima accident reveals the vulnerability of existing active nuclear power plant (NPP) design against prolonged loss of external electricity events. The passive safety system is considered an attractive alternative to cope with this kind of disaster. Also, the passive safety system enhances both the safety and the economics of NPPs. The adoption of a passive safety system reduces the number of active components and can minimize the construction cost of NPPs. In this paper, reflecting on the experience during the development of the APR+ design in Korea, we propose the concept of an innovative Power Reactor (iPower), which is a kind of passive NPP, to enhance safety in a revolutionary manner. The ultimate goal of iPower is to confirm the feasibility of practically eliminating radioactive material release to the environment in all accident conditions. The representative safety grade passive system includes a passive emergency core cooling system, a passive containment cooling system, and a passive auxiliary feedwater system. Preliminary analysis results show that these concepts are feasible with respect to preventing and/or mitigating the consequences of design base accidents and severe accidents.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.360-372
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• 2017

Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.22-28
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• 2010

This study analyzed the performance of passive solar system for office building. A unit model of the passive solar system was proposed in order to predict its performance under varying parameters and Seoul weather date. Steady state heat transfer equations were set up using a energy balanced equations and solved using a inverse matrix method. Numerical simulation program to analyze system was developed by using MATLAB. As the results, the passive solar system performance of office building was determined by the insolation and the outdoor air temperature. Also the passive solar system indicate 6.7~16.2% of annual average efficiency. In the comparison with other systems of the conventional wall, mass wall could reduce the heating loads of 7.1% and trombe wall could reduce heating loads of 11.5%. Through this study, performance of passive solar system for office building was verified by numerical method. Consequently, the passive solar system could operate an important role as the alternative for saving energy consumption of office building, and the additional studies should be made through the experimental method for the commercialization.

• Smart Structures and Systems
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• v.3 no.3
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• pp.385-403
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• 2007

The effectiveness of the newly developed smart passive control system employing a magnetorheological (MR) damper and an electromagnetic induction (EMI) part for seismic protection of base isolated structures is numerically investigated. An EMI part in the system consists of a permanent magnet and a coil, which changes the kinetic energy of the deformation of an MR damper into the electric energy (i.e. the induced current) according to the Faraday's law of electromagnetic induction. In the smart passive control system, the damping characteristics of an MR damper are varied with the current input generated from an EMI part. Hence, it does not need any control system consisting of sensors, a controller and an external power source. This makes the system much simpler as well as more economic. To verify the efficacy of the smart passive control system, a series of numerical simulations are carried out by considering the benchmark base isolated structure control problems. The numerical simulation results show that the smart passive control system has the comparable control performance to the conventional MR damper-based semiactive control system. Therefore, the smart passive control system could be considered as one of the promising control devices for seismic protection of seismically excited base isolated structures.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.112-114
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• 1998

The passive system requires RF-DC converter. RF-DC converter, which is used in microwave region, is more affected by parasitic elements than used in low frequency region. So it is difficult to make the converter. RF-DC converter usually consists of resonator, shottky diode, capacitor, voltage regulator. In this study, we used the rechargeable battery instead of capacitor. If any passive transponder requires more power than general transponder, battery tech of this components is important to apply for the passive system. In this paper, passive transponder, which requires more power than general passive transponder, is presented and compared to general passive transponder.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1951-1953
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• 1998

In this study, we present the power conversion system of the passive transponder which is operated at 2.4GHz. First, The passive transponder which is the power conversion system is one of the passive transponder elements is presented. And then the power conversion system is analyzed and simulated.