• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.331-341
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• 2015

In this paper, real-time water quality monitoring system of small water supply facilities based on IEEE 802.15.4e-2012 DSME MAC and IEEE 802.15.4g-2012 PHY standard is presented, which is capable to acquire for highly reliable water quality information in the wide outdoor areas for effective water quality management of small water quality facilities is distributed in the long distance and remote areas. Previously, Long distance transmission is difficult in most water quality sensor module is using RS-485 protocol. But with this system, even in harsh outdoor environment, it is possible to establish a radio wave sensor in a wide area network, and not only water quality sensor shall be connected to the wireless system, but also wireless integrated management system shall provide more effective way of management of the numerous small water supply facilities spread throughout the community, so that the administrator can remotely monitor the data of water turbidity, pH, residual chlorine in the water-supply, water-level, and generate alarm to cope with risks. The management of small water facilities is done by residents will be very effective to notice water quality information of small water facilities to residents.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.984-990
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• 2014

Polymers are the most commonly used di-electrics because of their reliability, availability, ease of fabrication and cost. The commercial and industrial demand for advanced polymeric materials which are capable of being used in harsh environment is need of the hour. The study of the effect of electron beam irradiation on polymeric materials is an area of rapidly increasing interest. This paper discusses the resultant beneficial effects of electron beam irradiation on the SiR-EPDM blend having 50:50 composition. The changes in mechanical and electrical properties of SiR-EPDM blend which are exposed to three different doses of electron beam radiation namely 5 Mrad, 15 Mrad and 25 Mrad are presented. The irradiated blends are analyzed for their electro-mechanical and physico chemical properties. The electrical changes induced by irradiation are investigated by arc resistance, surface resistivity and volume resistivity measurements as per ASTM standards. The mechanical changes are observed by the measurement of tensile strength and elongation at break. Physico chemical investigation has been done using the FTIR, in order to investigate the irradiation induced chemical changes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.540-543
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• 2010

POWER PC series are common to the Central Processing Unit for Military Single Board Computer. Among them, G4 group, which contains the 74xx series supported by Freescale manufacturer is mainly used in the Military applications. We focus on the Interface between memory and controller. PCB stacking method, component routing, impedance matching and harsh environment for Military spec are the main constraints for implementation. Also, we developed memory as a module for the consideration of Military environments. The overall type of SBC should be designed by the form of 6U VME or 3U VME.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.25-26
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• 2006

An electrical fault is defined as any abnormal condition caused by reduction in the insulation strength between energized conduction parts and ground or any grounded part of an electrical system. Failure of solid insulation can be caused by excessive mechanical tension being applied on the insulation, harsh service environment, aging, and also by corona phenomena. The number of empty houses during normal working hours is rising. As a result, the number of uninspected electric installation for general use is increasing. To define the potential risk of the electric installation, measurement of leakage current has been getting considered, but because the measured leakage current value also contained leakage current by capacitance, the measured value can not be adapted to absolute reference to the installation. Therefore, in this paper, the correlation between the condition of electric installation and leakage current were analyzed.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.890-898
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• 2018

Nondestructive inspection (NDI) is an integral part of structural integrity analyses of dry storage casks that house spent nuclear fuel. One significant concern for the structural integrity is stress corrosion cracking in the heat-affected zone of welds in the stainless steel canister that confines the spent fuel. In situ NDI methodology for detection of stress corrosion cracking is investigated, where the inspection uses a delivery robot because of the presence of the harsh environment and geometric constrains inside the cask protecting the canister. Shear horizontal (SH) guided waves that are sensitive to cracks oriented either perpendicular or parallel to the wave vector are used to locate welds and to detect cracks. SH waves are excited and received by electromagnetic acoustic transducers (EMATs) using noncontact ultrasonic transduction and pulse-echo mode. A laboratory-scale canister mock-up is fabricated and inspected using the proposed methodology to evaluate the ability of EMATs to excite and receive SH waves and to locate welds. The EMAT's capability to detect notches from various distances is evaluated on a plate containing 25%-through-thickness surface-breaking notches. Based on the results of the distances at which notch reflections are detectable, NDI coverage for spent nuclear fuel storage canisters is determined.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.127-134
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• 2005

The machine vision has been applied to a number of industrial applications for quality control and automations to improve the manufacturing processes. In this paper, the automation system using the machine vision is developed, which is applicable to the marking process in a steel production process line. The working environment is very harsh to workers so that the automatic system in the steel industry is required increasingly. The developed automatic marking system consists of several mechanical and electrical elements such as the laser position detecting sensor system fur a structured laser beam which is projected to the billet in order to detect the geometry of the billet. An image processing algorithm has been developed to percept the two center positions of a camera and a billet, respectively, and to align two centers. A series of experiments has been conducted to investigate the performance of the proposed algorithm. The results show that two centers of the camera and the billet could be detected very well and differences between two center positions could be also decreased via the proposed location error decreasing algorithm.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.105-120
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• 2015

Enterprise should determine the adoption and utilization of information systems would be a great help to increase management performance. So, it maintains continually the budget and the investment for informatization. However, there is a limit to clarify whether the investment in informatization is contributed to create business opportunities through corporate competitiveness certainty or not. We tend to recognize the information system as a simple means to support common business rather than being used to achieve the company's business performance and to remain competitive. It is not an easy problem for the quantitative evaluation and analysis on the effect of intangible, such as management performance measurement by introducing computerization project. Informatization level evaluation model for the harsh business environment, specifically the Small and Medium Enterprise is lacking. In this paper, we proposed the audit evaluation model of an Small and Medium Enterprise informatization level based on system quality, information quality, user satisfaction, and IT business contribution. The proposed audit evaluation model was evaluated in the information system users, and verified the suitability throughout the survey of the audit professionals.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.270-277
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• 2019

Inspired by small insects, which perform rapid and stable locomotion based on body softness and tripod gait, various milli-scale six-legged crawling robots were developed to move rapidly in harsh environment. In particular, cockroach's leg compliance was resembled to enhance the locomotion performance of the crawling robots. In this paper, we investigated the effects of changing leg compliance for the locomotion performance of the small light weight legged crawling robot under various payload condition. First, we developed robust milli-scale six-leg crawling robot which actuated by one motor and fabricated in SCM method with light and soft material. Using this robot platform, we measured the running velocity of the robot depending on the leg stiffness and payload. In result, there was optimal range of the leg stiffness enhancing the locomotion ability at each payload condition in the experiment. It suggests that the performance of the crawling robot can be improved by adjusting stiffness of the legs in given payload condition.

• Bulletin of the Society of Naval Architects of Korea
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• v.24 no.2
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• pp.29-35
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• 1987

As offshore activities move into deeper ocean, conventional fixed-base platforms drastically increase in size and cost, One of alternatives available is a guyed tower, in which environmental loads are supported by guylines instead of structural members. The guying system of the guyed tower is designed on one hand to be stiff enough to limit the structural displacement in normal operations, but on the other hand to be soft enough to permit large slow sways during the presence of design-level storms. This compliancy provides an efficient means of withstanding harsh environment so that the disproportionate increase in size of deep water platforms can be kept to a rational limit. Novel configurations contain always some degrees of potential risks mainly due to the lack of experience. The most critical hazard inherent to a guyed tower may be the pullout of anchor piles. Once it happens, the guyline fails to function and it may eventually lead to the total collapse of the system. It is the aim of this paper to discuss and quantify the anchor-pullout risk of a guyed tower. A stochastic analysis is made for evaluating the first-upcrossing probability of the tension acting on anchor piles over the uplift capacity. Nonlinearities involved in the mooring stiffness and hydrodynamics are taken into account by using time-domain analysis. A simplified two dimensional dynamic model is developed to exemplify the underlying concept. Real hurricane data in the Gulf of Mexico spanning over 70 years are incorporated in a numerical example of which result clearly indicates highly potential risk of anchor pullout.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.10
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• pp.821-828
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• 2021

Quadrotors relatively smaller and lighter than other aircraft have a disadvantage of being sensitive to the external disturbances. In order to solve this disadvantage, many studies have been conducted by various control techniques robust to disturbances. In this paper, CMGs (Control Moment Gyros) introducing relatively large control torque with an identical amount of electric powers are applied to cancel the external disturbances. Two CMGs are considered to control the attitude of quadrotors so that a multi-copter installed with two CMGs and four rotors are introduced for this work. Finally, to verify the control performance of the proposed system by the CMGs, a numerical simulation conducted in the given harsh environment.