• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1313-1314
• /
• 2006

The polycrystalline 3C-SiC thin films heteroepitaxially grown by LPCVD method using single precursor 1,3-disilabutane at $850^{\circ}C$. The crystallinity of the 3C-SiC thin film was analyzed by XRD and FT-IR. Residual strain was investigated by Raman scattering. The surface morphology was also observed by AFM and voids or dislocations between SiC and $SiO_2$ were measured by SEM. The grown poly 3C-SiC thin film is very good crystalline quality, surface like mirror, and low defect and strain. Therefore, the polycrystalline 3C-SiC is suitable for harsh environment MEMS applications.

• International Journal of Aeronautical and Space Sciences
• /
• v.18 no.3
• /
• pp.555-564
• /
• 2017

In this paper, a new technique for attitude and heading reference system (AHRS) using low-cost MEMS sensors of the gyroscope, accelerometer, and magnetometer is addressed particularly in vibration environments. The motion of MEMS sensors interact with the scale factor and cross-coupling errors to produce random errors by the harsh environment. A new adaptive attitude estimation algorithm based on the Kalman filter is developed to overcome these undesirable side effects by analyzing windowed measurement error covariance. The key idea is that performance degradation of accelerometers, for example, due to linear vibrations can be reduced by the proposed measurement error covariance analysis. The computed error covariance is utilized to the measurement covariance of Kalman filters adaptively. Finally, the proposed approach is verified by using numerical simulations and experiments in an acceleration phase and/or vibrating environments.

• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.11
• /
• pp.178-181
• /
• 1996

The Outflow facility of eye ball provides crucial informations in the diagnose of ophthalmological glaucoma. Tn this study an ophthalmic outflow facility measuring device is developed and experimentally tested. This system employs pressure sensors and linear positioning device to regulate solution reservoir height, the pressure of eye ball. The experimental result show that the system works well even in harsh environment so that it can be implemented in ophthalmic practice as well as in biomedical research.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.168-171
• /
• 2009

The solar lighting system has been popular in these days. It is composed of solar panel, controller, and battery. The battery is charged during the day time, and discharged at the night time. The battery status should be carefully controlled in order to guarantee the safe operation. If there were measurement noise or system noise, the performance of controller could be degraded. In this paper, the state estimator design in the noisy environment is proposed. The proposed system shows the excellent tracking performance under in harsh conditions.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2199-2201
• /
• 2001

The 3-dimensional measuring machine by using an ultrasonic sensor is used one of the NDE(Nondestructive Examination). It is applied to the inspection of pipelines, boreholes, pressure vessel and tank, and so on. In particular when a harsh environment prohibits the use of moving mechanical parts. The 3-dimensional measuring machine by using an ultrasonic sensor, which measure 1-dimensional information and 2-dimensional information simultaneously from a target of inspection, and then reembody 3-dimensional information. So we can find the situation in progress and predict remaining life and corrosion without destructive examination. It's a point of excellence that the 3-dimensional measuring machine is portable.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.74-76
• /
• 2002

The suspension insulators are subjected to harsh environment in service for a long time. Long term reliability of the insulators is required for both mechanical and electrical performances. We studied an analysing method to find out a deformation of brittle porcelain with a thermal expansion of cement for suspension insulator. These simulation analysis and experimental results show that cement volume growths affect severely to be mechanical failure ageing.

• Journal of the Microelectronics and Packaging Society
• /
• v.26 no.3
• /
• pp.1-6
• /
• 2019

Wettability is an important factor to decide solderability of solder, flux, other soldering-related materials and soldering conditions. The wettability also affects the reliability of solder joint. Wetting balance test is a good method for quantitatively measuring wettability between solder and substrate. The wetting balance test is easy to reproduce the wetting experiment and to measure the wetting time and force. And this test provides wetting curve to calculate the surface tension of the molten solder. Development of new solder has been continued in accordance with various and harsh environment in the electronics industry. In this paper, the principle of wetting balance test and recent research issues including nano-composite solder are explained.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.1
• /
• pp.39-59
• /
• 2014

Nowadays aluminum stiffened plates are one of the major constituents of the marine structures, especially high-speed vessels. On one hand, these structures are subject to various forms of loading in the harsh sea environment, like hydrostatic lateral pressures and in-plane compression. On the other hand, fusion welding is often used to assemble those panels. The common marine aluminum alloys in the both 5,000 and 6,000 series, however, lose a remarkable portion of their load carrying capacity due to welding. This paper presents the results of sophisticated finite-element investigations considering both geometrical and mechanical imperfections. The tested models were those proposed by the ultimate strength committee of $15^{th}$ ISSC. The presented data illuminates the effects of welding on the strength of aluminum plates under above-mentioned load conditions.

• Electronics and Telecommunications Trends
• /
• v.36 no.5
• /
• pp.92-102
• /
• 2021

Owing to various restrictions in-field application, the low-speed, low-power-based industrial Internet-of-Things (IoT) network built in extremely harsh industrial environment sites requires multi-hop, channel hopping, and low-latency transmission characteristics. In the past, wired networks were used in industrial facilities; however, network technologies based on the Industrial IoT Network standard standardized for industrial applications, such as WirelessIO link, WirelessHART, SmartMesh, and eStar Link satisfy industrial requirements. Recently, the use of industrial IoT networks in industrial facilities has rapidly expanded. This paper covers the developments in industrial IoT network technologies and summarizes the major industrial IoT standard technologies that meets the requirements of industrial sites.

• Journal of Positioning, Navigation, and Timing
• /
• v.9 no.4
• /
• pp.387-395
• /
• 2020

Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.