• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.317-322
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• 2015

The metal oxide varistor (MOV) is a major component of the surge protection devices (SPDs) currently in use. The device is judged to be faulty when fatigue caused by the continuous inflow of lightning accumulates and reaches the damage limit. In many cases, induced lightning resulting from lightning strikes flows in to the device several times per second in succession. Therefore, the frequency or the rate at which the SPD is actually exposed to stress, called a surge, is outside the range of human perception. For this reason, the protective device should be replaced if it actually approaches the end of its life even though it is not faulty at present, currently no basis exists for making the judgment of remaining lifetime. Up to now, the life of an MOV has been predicted solely based on the number of inflow surges, irrespective of the magnitude of the surge current or the amount of energy that has flowed through the device. In this study, nonlinear data that shows the damage to an MOV depending on the count of surge and the amount of input current were collected through a high-voltage test. Then, a failure prediction algorithm was proposed by preparing a look-up table using the results of the test. The proposed method was experimentally verified using an impulse surge generator

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.69-78
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• 2017

As the smartphone-based devices are diffused and developed rapidly, they provide the convenience to the users. The abovementioned sentence technologies are being used not only in the existing sensor and wireless network technology but also in the application services of the diverse fields application services such as smart appliance, smart car, smart health care, etc. and the new fusion paradigm from the industry is presented by undertaking the researches in diverse area by the enterprises and research institutions. However, the smart environment exposes its weaknesses in the mobile terminal area, existing wireless network and IT security area. In addition, due to new and variant ways of attack, not only the critical information are disclosed However also the financial damages occur. This paper proposed the protocol to perform the smartphone-based safe device monitoring and safe communication. The proposed protocol designed the management procedure of registration, identification, communication protocol and device update management protocol and the safety against the attack techniques such as the an-in-the-middle-attack, impersonation attack, credential threat, information leaks and privacy invasion was analyzed. It was observed that the proposed protocol showed the performance improved by approximately 52% in the communication process than the existing system.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.76-85
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• 2006

In the manufacture of liquid crystal display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic transportation device for glass panels is proposed. This device can directly drive a glass panel and simultaneously provide contactless suspension by electrostatic forces. To accomplish these two functions, a feedback control strategy and the operational principle of an electrostatic induction motor are utilized. The stator possesses electrodes which exert electrostatic farces on the glass panel and are divided into a part responsible for suspension and one for transportation. To accomplish dynamic stability and a relatively fast suspension initiation time, the structure of the electrode for suspension possesses many boundaries over which potential differences are formed. In this paper, an electrode pattern suitable for the suspension of glass panels is described, followed by the structure of the transportation device and its operational principle. Experimental results show that the glass panel has been transported with a speed of approximately 25.6 mm/s while being suspended stably at a gap length of 0.3 mm.

• Archives of Reconstructive Microsurgery
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• v.15 no.2
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• pp.51-57
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• 2006

Free flap having been used for reconstruction of skin and soft tissue defect in various areas in a body is spreading up its application for not only functional reconstruction but also aesthetic reconstruction. Authors met with good results minimizing the demerits of anastomosis using suture through microvascular anastomotic device, hereupon, we intend to report this. We worked with 27 cases that used microvascular anastomotic device for venous anastomoses among patients who were processed free flap in our hospital. Age ranged from 12 to 63 (average 43.2), and there were 12 females and 15 males. As a result of a follow-up by 3 months - 5years (average 11.3 months), there was no particular complication in the anastomosed vein except 1 cases among 27 cases that sutured their veins through microvascular anastomotic device. Use of microvascular anastomotic device at free flap shortened the time required for vascular anastomoses to reduce ischemic time of tissue, and minimized the damage of intima during anastomoses and made easy anastomoses possible even in case the difference of diameters of blood vessels being sutured is wide. As well, even for survival rate of flap, satisfactory results were obtained compared with using suture. Consequently, it is concluded that use of microvascular anastomotic device in free flap is a useful way that can substitute existing anastomosis using suture.

• Journal of KIISE
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• v.43 no.11
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• pp.1179-1187
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• 2016

Android- and Linux-based embedded systems require device drivers, which are structured and built in kernel functions. However, device driver software (firmware) provided by various 3rd parties is not usually checked in terms of their security requirements but is simply included in the final products, that is, Android-based smart phones. In addition, static analysis, which is generally used to detect vulnerabilities, may result in extra cost to detect critical security issues such as privilege escalation due to its large proportion of false positive results. In this paper, we propose and evaluate an effective technique to detect vulnerabilities in Android device drivers using both static and dynamic analyses.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.5 no.1
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• pp.79-85
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• 2011

In this paper, we proposed a design of upper-limb rehabilitation device with power-assist function for stroke survivals. The designed upper-limb rehabilitation device has three degrees of freedom； it is possible to perform flexion and extension motions of wrist, index finger and the other fingers except the thumb independently. The power-assist for wrist motion is performed by a pneumatic double-acting cylinder, but the fingers are actuated by electrical linear actuators to assist motions. A prototype upper-limb rehabilitation device and its controller were implemented. The position controller showed 0.8 mm errors in the steady-state. Experimental results showed that the proposed upper-limb rehabilitation device with power-assist function is feasible.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.435-445
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• 2003

Tension member is one of the most important elements in tension structure. An economical and reliable measurement method of a member's tensile force has yet to be developed, however. Several conventional measurement methods have some disadvantages when used for long-term, on-site measurement. A new tension-force measurement device was proposed to resolve measuring problems. Its principle was to use the bending part of the device as an elastic spring. The lateral deformation of the bending part due to tensile force can be measured to monitor the tensile force. This device was inserted in the tension member like a turn-buckle. Lateral deformation may be measured in the field at any time for the purpose of maintaining structures. Finite element analysis was used to design the shape and parametric study. Six specimens were tested within the elastic range. The test result showed that the elastic behavior or the bending part was consistent with the analysis' results.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.98-103
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• 2015

A flow passage opening device utilizing an acceleration follow-up technique allows fuel to flow continuously through a pressurized fuel tank system. It is very difficult to test the device in a real flight situation because of severe test condition and a cost problem. In this paper, therefore, the results of a basic negative g test conducted by low-speed airplane are compared with RecurDyn simulation. Dynamic behavior of the device in total flight profile of a high-speed vehicle is also analyzed by using RecurDyn to predict its performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.331-334
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• 2000

The organic electroluminescent(EL) device has gathered much interest because of its large potential in materials and simple device fabrication. We fabricated EL devices which have a blended single emitting layer containg poly(Nvinylcarbazole)[PVK] and poly(3-dodecylthiophene)[P3DoDT]. The molar ratio between P3DoDT and PVK changed with 1:0, 2:1 and 1:1. To improve the external quantum efficiency of EL devices, we applied insulating layer, LiF layer between polymer emitting layer and AI electrode. All of the devices emit orange-red light and it's can be explained that the energy transfer occurs from PVK to P3DoDT. Within the molar ratio 1:0, 2:1 and 1:1, the energy transfer was not saturated, which results in the not appearance of PVK emission in the blue region. In the voltage-current and voltage-light power characteristics of devices applied LiF layer, current and light power drastically increased with increasing with applied voltage. In the consequence of the result, the light power of the device have a molar ratio 1:1 with LiF layer was about 10 times larger than that of the device without PVK at 6V.

• Journal of Sensor Science and Technology
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• v.17 no.1
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• pp.81-85
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• 2008

This paper addressed real-time urine monitoring device for intensive care patients. The device was developed to detect and count each urine drop using optical sensor and calculate the current urine output volume and its hourly rate. In experiment, the water volume scale of drainage bottle was observed and compared with the count of the device so that the volume of each drop was found to vary with the dropping rate per minute. From this measurement, the relationship equation was derived to estimate the total water volume from the drop rate (correlation coefficient : r= 0.99). The developed device could be applied to count patient's urine drop successfully. Therefore, this device can be used to monitor intensive care patient's urine status in real-time.