• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.143-145
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• 2016

In order to find suitable source and drain (S/D) electrodes for amorphous InGaZnO thin film transistors (a-IGZO TFTs), the specific contact resistance of interface between the channel layers and various S/D electrodes, such as Ti/Au, a-IZO and multilayer of a-IGZO/Ag/a-IGZO, was investigated using the transmission line model. The a-IGZO TFTs with a-IGZO/Ag/a-IGZO of S/D electrodes had good performance and low contact resistance due to the homo-junction with channel layer. The stability was measured with different electrodes by a positive bias stress test. The result shows the a-IGZO TFTs with a-IGZO/Ag/a-IGZO electrodes were more stable than other devices.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.975-979
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• 2001

In connection with the monitoring of the insulation degradation of large power apparatus in order to predict their expected service failures, a statistical treatment, such as phase resolved partial discharge analysis (PRPDA), has been established for the on-line monitoring system during the past decades. However, this method has shown some inconveniences to identify the nature of the PD source in power apparatus. In this regard, a novel approach based on the chaotic analysis (CAPD) is proposed describing the fundamental ideas, outcomes and different viewpoints from the conventional PRPDA. As a model for the possible defects causing sudden failures in service, three types of specimen are prepared. And partial discharge signals, originated from those samples, are measured and analyzed by means of CAPD. Throughout this work, it seems that the correlation between the consecutive PD pulses, depending on the nature of PD, could be clarified by CAPD. Thereffre, it could be considered that the nature of PD source can be identified more distinctively when the CAPD is combined with PRPDA.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.12
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• pp.1995-2000
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• 1989

The ion beam system of 20keV C-W (Cockroft Walton) type composed of the AuGe alloy LMIS(Liquid Metal Ion Source) has been designed and constructed. For the fabrication of the ohmic contact to the n-GaAs, the ion beam extracted from the AuGe alloy source was implanted into the n-GaAs, and it was measured by contact resistivity. The stable AuGe ion beam(2.5\ulcorner/cm\ulcorner was obtained at the extraction voltage of 14.5kV. The measurements of the contact resistivity were done by the TLM (Transmission Line Model) method and the specific contact resistivity was found to be 2.4x10**-5 \ulcornercm\ulcornerfor the implanted sample by the 1.9x10**20/cm**3 and the annealed sample at 30\ulcorner for 2 min.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8940-8947
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• 2015

Mixed-model assembly line has been widely used in automotive assembly industry to quickly respond the diverse product demands. But, this model can lead to part confusion, which is a source for assembly errors when parts are physically interchangeable in a mixed-model assembly line. With the recent application of new technologies such as radio frequency identification (RFID) and ZigBee wireless sensor network (WSN) to the assembly process, real-time information has become available in this manufacturing systems through IT infrastructures. At first, this paper presents an RFID application for assembly processes, specifically, for a mixed-model assembly line. Thus, to ensure that parts be picked accurately, each cockpit module on the assembly line is attached with a RFID tag and the tag is scanned using a RFID reader and recognizes the vehicle, and each part of the cockpit module is attached with a barcode and the barcode is scanned by a barcode reader and each part is identified correctly for the vehicle. Second, this paper presents a ZigBee wireless sensor network (WSN) protocol-based application for a reconfigurable mixed-model assembly line of cockpit module to reduce the assembly errors and the cost of the change/reconfiguration on the assembly lines due to the various orders and new models from the motor company, avoiding the wiring efforts and inconvenience by wiring between the several RFID devices and the IT server system. Finally, we presents the operation results for several years using this RFID/ZigBee wireless sensor network (WSN) protocol-based cockpit module assembly line.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.157-158
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• 2006

This paper describes the overvoltage of branch line in underground distribution systems when the direct lightning surge strikes on conductor of overhead line. Distribution systems are very complex because that includes so many branch lines, transformers, switches and so on. Therefor model systems consist of overhead distribution lines, underground cable include branch lines, lightning source and switches. Those are established by EMTP/ATPDraw. Simulation analyzes surge behavior on branch lines considering various conditions in underground distribution systems. Simulation results shoe overvoltage with location in various cases.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.145-147
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• 2002

In this paper, the improved fault locating method using distributed parameter which calculating the reduced voltage and current according to the ground capacitance in long transmission line was proposed. For the purpose of the fault locating algorithm non influenced source impedance, the loop method was used in the system modeling analysis. To enhance the fault locating, zero sequence of the fault current which is variable according to ground capacitance was not used but positive and negative sequence. System model was simulated using EMTP software. To verify the accuracy of proposed method, in different cases 64 sampled data per cycle was used and 160km and 300km long transmission line has fault resistance $0{\Omega}\;and\;100{\Omega}$ respectively was compared.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.53.2-53.2
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• 2011

A small number of active galactic nuclei are known to exhibit prominent double peak emission profiles indicating the presence of a relativistic accretion disk model. Using a Monte Carlo technique, we compute the linear polarization of a double peaked broad emission line. A Keplerian accretion disk is adopted for the double peak emission line region and the Schwarzschild geometry is assumed in the emission region. Far from the accretion disk where flat Minkowski geometry is appropriate, we place a scattering region in the shape of a spherical shell sliced. We generate a line photon in the accretion disk in an arbitraray direction in the local rest frame and follow the geodesic of the photon until it hits the scattering region. The profile of the polarized flux is mainly determined by the relative location of the scattering region with respect to the emission source. When the scattering region is in the polar direction, the linear degree of polarization also shows a double peak structure. Under a favorable condition we show that up to 1% of linear degree of polarization may be obtained.

• Journal of Power Electronics
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• v.1 no.1
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• pp.48-55
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• 2001

This paper describes a switching-level simulation model and scaled hardware model for SSSC, which is useful for analyzing the dynamic interaction between the SSC and the power transmission system. A detailed simulation model with EMTP was developed to verity the SSSC operation with control system, and its increasing capability of power transmission through the line for a typical one-machine infinite-bus system. The simulation results of the developed model are compared with the experimental results froma scaled model fo 2KVA rating for evaluation the whole system operation.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.10-14
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• 2015

Video Content owners seek to squeeze the maximum amount of revenue from their assets via distribution into more territories. Digital Cinema Package(DCP), trusted solution to distribute protected content to theaters, caters to relatively small user base, which limits revenue. With the growth of the Internet & other digital media, the economics of media content has changed dramatically. Security remains main concern to deliver content to millions of consumers using intelligent digital display devices like Tablets, Smartphones, Smart TVs, Desktop & Laptop. By making the video content available to this segment securely, content owners will benefit from increased revenue. Through this paper we propose Open Source HomeDCP model to distribute the content to home users for offline viewing. We propose to include other open source CODEC than JPEG2000/MPEG2, which are specifically designed for theatrical performance. Final image size will be further reduced considering the display device resolution where video will be finally played. Key Delivery Message(KDM) system to be altered to suit new devices. This will be a big boost to Content Economy as content owners would be able to distribute the content securely to the wider audience & ensure more revenue.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2534-2546
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• 2021

Nuclear emergency preparedness and response is an essential part to ensure the safety of nuclear power plant (NPP). Key support technologies of nuclear emergency decision-making usually consist of accident diagnosis, source term estimation, accident consequence assessment, and protective action recommendation. Source term estimation is almost the most difficult part among them. For example, bad communication, incomplete information, as well as complicated accident scenario make it hard to determine the reactor status and estimate the source term timely in the Fukushima accident. Subsequently, it leads to the hard decision on how to take appropriate emergency response actions. Hence, this paper aims to develop a method for rapid source term estimation to support nuclear emergency decision making in pressurized water reactor NPP. The method aims to make our knowledge on NPP provide better support nuclear emergency. Firstly, this paper studies how to build a Bayesian network model for the NPP based on professional knowledge and engineering knowledge. This paper presents a method transforming the PRA model (event trees and fault trees) into a corresponding Bayesian network model. To solve the problem that some physical phenomena which are modeled as pivotal events in level 2 PRA, cannot find sensors associated directly with their occurrence, a weighted assignment approach based on expert assessment is proposed in this paper. Secondly, the monitoring data of NPP are provided to the Bayesian network model, the real-time status of pivotal events and initiating events can be determined based on the junction tree algorithm. Thirdly, since PRA knowledge can link the accident sequences to the possible release categories, the proposed method is capable to find the most likely release category for the candidate accidents scenarios, namely the source term. The probabilities of possible accident sequences and the source term are calculated. Finally, the prototype software is checked against several sets of accident scenario data which are generated by the simulator of AP1000-NPP, including large loss of coolant accident, loss of main feedwater, main steam line break, and steam generator tube rupture. The results show that the proposed method for rapid source term estimation under nuclear emergency decision making is promising.