• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.11
• /
• pp.2089-2092
• /
• 2010

There are many cases that interrupt the production process because of malfunctions caused by electronic circuit boards which control equipment, but it is difficult to distinctly identify the causes in many cases. Especially, CMOS devices with the control logic circuit return automatically to normal state after their own faults. Therefore it is not easy to analyze the problems with electronic circuit boards. Recently, nuclear power plant experienced a failure due to the malfunction of electronic circuit boards and it was identified that the reason of the malfunction was because of latch-up phenomenon caused by external surge in electronic devices. This paper presents the causes and the phenomenon of latch-up by experiment and also a way using counter EMF diodes, noise filters and surge protective devices to prevent latch-up phenomenon from electronic circuit boards, finally confirms the effectiveness of the result by experiment.

• Smart Media Journal
• /
• v.2 no.1
• /
• pp.17-26
• /
• 2013

Electronic bulletin boards, has been used as an effective tool in various information delivery. However, many electronic bulletin board as a one-way information passed by the interactivity is lacking. In this paper, the interaction of the information, while maintaining an electronic bulletin board that can be operated on a variety of platforms, the Android-based software and hardware for the design and implementation. The interaction of users of electronic bulletin boards, and information can be naturally-type content support Android framework was designed to allow Android APP. Android APP using the administrator also was designed automatic installation and FORUMS so that you can run. Naturally gather information, and all the people that interact through bulletin boards, so you can take advantage.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.32 no.2
• /
• pp.53-69
• /
• 2007

Internet shopping websites have offered comfort to consumers in shopping and built trust relationships with them by providing electronic agents for recommendation, escrow services, and customer centers etc. But as there is little big difference among the shopping websites in terms of technical competence, website design, operational policy, they recognize online feedback (reviews or recommendation of consumers or experts) and online feedback mechanism as important marketing tools. Based on online feedback related studies, this study explores antecedents (consensus, vividness of reviews, interactions in review boards) of the perceived effectiveness of review boards which are text-based feedback mechanisms and its consequences such as trust, satisfaction, and intention to use. The results show that the perceived effectiveness of review boards is significantly affected by vividness of reviews and interactions in review boards, and the impact of interaction in review boards on the perceived effectiveness of review boards is stronger than that of vividness of reviews. The results also show that the perceived effectiveness of review boards has a significant influence on trust and satisfaction with the shopping websites, and intention to use is influenced by both trust and satisfaction.

• Journal of the Korean Society of Safety
• /
• v.13 no.2
• /
• pp.22-29
• /
• 1998

The natural convection cooling of simulated electronic chips located on a printed circuit board(PCB) has been studied by Computer Aided Engineering(CAE). In CAE, 3-dimensional finite element model of simulated electronic chip was made to accomplish heat transfer analysis at each design stage of a printed circuit boards for thermal optimization. The simulated electronic chips are installed protrudent from the plate about 3mm. The materials the plates are epoxy and aluminum. The results show that the chip with relatively high heat generation rates should not be close to each other. It is found, as well that cooling effect for the aluminum plate is superior to the epoxy plate and location of maximum temperature is significantly influenced by the structure variation of PCB. In developing PCB and electronic chips, it's recommended that CAE is very useful to estimate to the distribution of temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.264-265
• /
• 2008

While the reliability of bulk insulation has become important particularly in multilayer boards and embedded boards, electronics are to be used under various environments such as at high temperature and in high humidity. We observed internal space charge behavior for two types of epoxy composites under dc electric fields to investigate the influence of water at high temperature. In the case of glass/epoxy specimen, homocharge is observed at water-treated specimen, and spatial oscillations become clearer in the water-treated specimens. Electric field in the vicinity of the electrodes shows the injection of homocharge. In aramid/epoxy specimens, heterocharge is observed at water-treated specimens, i.e. negative charge accumulates near the anode, while positive charge accumulates near the cathode. Electric field is enhanced just before each electrode. In order to further examine the mechanism of space charge formation, we have developed a new system that allows in situ space charge observation during ion migration tests at high temperature and high humidity. Using this in situ system.

• Nuclear Engineering and Technology
• /
• v.54 no.11
• /
• pp.3985-3995
• /
• 2022

The emergence of new nanoscale technologies has imposed significant challenges to designing reliable electronic systems in radiation environments. A few types of radiation like Total Ionizing Dose (TID) can cause permanent damages on such nanoscale electronic devices, and current state-of-the-art technologies to tackle TID make use of expensive radiation-hardened devices. This paper focuses on a novel and different approach: using machine learning algorithms on consumer electronic level Field Programmable Gate Arrays (FPGAs) to tackle TID effects and monitor them to replace before they stop working. This condition has a research challenge to anticipate when the board results in a total failure due to TID effects. We observed internal measurements of FPGA boards under gamma radiation and used three different anomaly detection machine learning (ML) algorithms to detect anomalies in the sensor measurements in a gamma-radiated environment. The statistical results show a highly significant relationship between the gamma radiation exposure levels and the board measurements. Moreover, our anomaly detection results have shown that a One-Class SVM with Radial Basis Function Kernel has an average recall score of 0.95. Also, all anomalies can be detected before the boards are entirely inoperative, i.e. voltages drop to zero and confirmed with a sanity check.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.625-628
• /
• 1999

Recently. high-density printed circuit boards(PCB) become indispensable with the minaturization of components. Nickel is deposited on the copper patterns and followed by the gold deposition for improving connection reliability between the printed circuit boards and electronic components. Conventionally electrodeposition has been applied to metalization of copper patterns. However metalization by this method is not applicable for the isolated fine and concentrated patterns. Therefore, metalization technology of the fine patterns by electroless plating is required in place of electrodeposition. The application of electroless nickel plating for interconnection with solder strongly relies on the solderability and the interactions between nickel and solder. Factors such as phosphorus content of the deposit additive and bath temperature may influence solderability of the electroless nickel deposit. So solderability of electroless nickel/ gold deposits was investigated with substrates plated changing the condition of nickel solution.

• Journal of Astronomy and Space Sciences
• /
• v.19 no.4
• /
• pp.283-292
• /
• 2002

Electronic boards of Far-ultraviolet IMaging Spectrograph (FIMS) should be designed to maintain their performances, and their temperatures should be remained within the allowed temperatures in operational environments. Thermal analysis at the electronic board level has been performed, and it is confirmed the electronics parts could be kept within their allowed temperature ranges.

• ETRI Journal
• /
• v.38 no.5
• /
• pp.903-910
• /
• 2016

We propose a novel multi-stack (MS) technique for a compact and wideband electromagnetic bandgap (EBG) structure in high-speed multilayer printed circuit boards. The proposed MS technique efficiently converts planar EBG arrays into a vertical structure, thus substantially miniaturizing the EBG area and reducing the distance between the noise source and the victim. A dispersion method is presented to examine the effects of the MS technique on the stopband characteristics. Enhanced features of the proposed MS-EBG structure were experimentally verified using test vehicles. It was experimentally demonstrated that the proposed MS-EBG structure efficiently suppresses the power/ground noise over a wideband frequency range with a shorter port-to-port spacing than the unit-cell length, thus overcoming a limitation of previous EBG structures.

• Journal of the Korean Society for information Management
• /
• v.30 no.4
• /
• pp.175-193
• /
• 2013

This study aims to investigate the current state of digital reference services using electronic bulletin boards in Korean academic libraries and to suggest improvements. Through the examination of 205 academic library websites, 56 libraries were identified to use electronic bulletin for digital references. The digital reference service questions and responses from four libraries were further analyzed: the types of reference question, the structure and accuracy of answers, and digital reference completion time. The implications of this study for future research and practice lie in its provision of a systematic way to design practical guidelines for virtual reference services.