• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1535-1541
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• 2019

To carry out safe and rapid decontamination in radiological accident areas, acquisition of various information on radiation sources is needed. In particular, to figure out the location and distribution of radiation sources is essential for rapid follow-up and removal of contaminants as well as minimizing worker damage. The radiation distribution detection device is used to obtain the position and distribution information of the radiation source. In the case of a radiation distribution detection device, a detection sensor unit is generally composed of a single sensor, and the detection range is limited due to the physical characteristics of the single sensor. We applied a calibration detector for controlling the detection sensitivity of a single sensor for radiation detection and improved the limited detection range of radiation dose rate. Also, gamma irradiation test confirmed the improvement of radiation distribution detection range.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.2
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• pp.173-180
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• 2017

In this study, air sampling locations in the stack of the Advanced Fuel Science Building (AFSB) at the Korea Atomic Energy Research Institute (KAERI) were assessed according to the ANSI/HPS N13.1-1999 specification. The velocity profile, flow angle and $10{\mu}m$ aerosol particle profile at the cross-section as functions of stack height L and stack diameter D (L/D) were assessed according to the sampling location criteria using COMSOL. The criteria for the velocity profile were found to be met at 5 L/D or more for the height, and the criteria for the average flow angle were met at all locations through this assessment. The criteria for the particle profile were met at 5 L/D and 9 L/D. However, the particle profile at the cross-section of each sampling location was found to be non-uniform. In order to establish uniformity of the particle profile, a static mixer and a perimeter ring were modeled, after which the degrees of effectiveness of these components were compared. Modeling using the static mixer indicated that the sampling locations that met the criteria for the particle profile were 5-10 L/D. When modeling using the perimeter ring, the sampling locations that met the criteria for particle profile were 5 L/D and 7-10 L/D. The criteria for the velocity profile and the average flow angle were also met at the sampling locations that met the criteria for the particle profile. The methodologies used in this study can also be applied during assessments of air sampling locations when monitoring stacks at new nuclear facilities as well as existing nuclear facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8927-8932
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• 2015

A directional feeding method at the railway transformer is applied for supplying the power to the electric railway substations, and the pre-installed facilities with common feeder are utilized in preparation for the failure of feeding system and in finding a fault location in case that the catenary failure occurs. However, it is some difficulty in finding the fault location since there is an interface problem with the facilities when the supplying power system operates. In this paper, Auto Fault Locator Transfer Drive System (ALTDS) is designed to search for the fault location efficiently, and the measuring data are obtained and compared with the KORAIL standards. Further, the ground connection test is accomplished 24 times as the verification method, and it is shown that the methodology provides better performance than the existing traditional one.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.595-600
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• 2016

다상 고정층 촉매반응기(Multiphase catalytic fixed-bed reactor)에서 기체 유동과 관련, 반응기 내부 구조 디자인에 따른 feed 가스의 분산성 변화를 분석하였다. 다상 촉매반응기의 경우 feed gas의 투입방법이 전체 공정의 반응효율을 크게 결정하는바 본 연구에서는 산업현장에서 활용도가 높은 환형 가스 주입부로 구성된 다상 고정층 촉매반응기를 대상으로 다양한 조건하에서 촉매 반응기 내부에서의 feed가스 분산성 변화를 분석하였다. 다상 촉매반응기의 feed gas 주입과 관련하여 다양한 방안이 제시되고 있는데 그 중 환형 가스 주입방식을 활용하는 방법은 타 기술대비 상대적으로 저렴한 투자비와 좁은 작업공간하에서 기체의 분산성을 향상 시킬수 있는 특징이 있어 실제 상업 공정에서의 활용성이 매우 높다. 본 논문에서는 특히 기-고 촉매 반응기 내부 반응기체의 분산성 향상을 위해 환형 가스 주입장치 내부에 설치된 가스 주입홀 구성방법에 따른 반응기 내부 유동을 분석하였다. 분석결과 주입홀의 위치가 가스 투입라인의 접선방향에 위치하는 것은 전체 분산성에 큰 영향을 주지 못하며 대부분 가스투입 입구와 맞은편 부분에 위치하는 경우 분산성이 향상되는 것으로 분석되었다. 결과적으로 환형 가스주입장치의 최적 설계는 feed 가스의 분산성에 큰 영향을 미치므로 초기단계에서 이러한 점을 고려한 설계 및 분석연구가 선행되어야 할 것으로 사료된다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.294-299
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• 2010

ELT(Emergency Locator Transmitter) is used to send distress signal in the event of an aircraft crash. It is very useful but the ELT may transmit wrong signal caused by misjudging between crash and hard-landing. The reason of this problem is the low accuracy of the mechanical G-switch currently in use. To improve the ELT, we developed an ELT system using the MEMS(Micro Electro-Mechanical Sensor) accelerometer. The ELT system consists of acceleration data acquisition/analysis system, program of crash recognition, and GPS receiving system for the position information of an aircraft crash site. A free-drop table was developed for verification of the ELT system. The free-drop table was designed to replicate the acceleration and the pulse duration of the hard landing and the crash. By using the free-drop table, we showed that the ELT system performed well.

• Journal of the Korean Magnetics Society
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• v.26 no.5
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• pp.154-158
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• 2016

A CRDM (Control Rod Drive Mechanism) is an electromagnetic device which drives a control rod assembly linearly to regulate the reactivity of a nuclear core. An RPIS (Rod Position Indication System) is used as a position indicator for a control rod assembly of a CRDM of SMART, and an RPIS consists of permanent magnets and reed switches. SMART is designed for the maximum coolant temperature of $350^{\circ}C$, and the permanent magnets are installed inside of the reactor. The reed switches and electrical circuit are installed outside of the reactor on the other hand. Test coil for a reed switch is test equipment for quality verification of a reed switch, and a test coil consists of a coil and core. In this study, magnetic property of test coil and permanent magnet on a reed switch is compared by using finite element electromagnetic simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.93-98
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• 2014

Bicycle accidents increase as the number of people riding bicycles increases following the trend try to enhance health and looking for alternative energy sources in the era of high oil price. In bicycle accident cases, physical risk is higher because the impact of the accident has a direct effect on the body of the rider. Therefore, the bicycle rider in an accident might unable to report the accident by themselves, thus, unable to quickly respond to the accident situation. This study developed a system for informing bicycle accidents upon bicycle accident by reporting and texting the accident location using a smart phone application after identifying the accident location using a GPS equipment based on the signal that senses the accident through the system installed in the bicycle for the purpose to improve bicycle riders' safety. This study confirmed the effectiveness of the system developed to quickly respond to the accident to prevent secondary damage through an experiment.

• Progress in Medical Physics
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• v.8 no.2
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• pp.19-26
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• 1997

3-dimensional Neuronavigator, Viewing Wand(ISG Technologies, Toronto, Cannda) is the surgery aid equipment for real time image (CT or MRI) guided surgery. The assurance of spatial accuracy of this system is important for clinical application. In this study, we have designed the acrylic brain phantom and measured the spatial error with that phantom. The phantom has designed to have capability to simulate image guided surgery. The phantom has 22 vertical rods whose diameters are 5mm and each rods has different length. CT scans were performed by 2.0mm slice and reconstructed for 3-Dimensional analysis. End point of rods can be obtained using reconstructed 3- Dimensional images and they are compared to actual position data. Average deviation was less than 2mm for various situations. Spatial error of Viewing Wand is acceptable in the clinical points of view, while cosmetics of the software needs to be modified to more user friend. Better accuracy can be expected when we apply the mixed fiducial fit registration and surface fit registration method. And even better results can be obtained if registration points distributed even and symetric around the target.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1A
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• pp.57-63
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• 2012

In this paper, we propose a real-time view interpolation method using virtual viewpoint disparity estimation and convergence check. For the real-time process, we estimate a disparity map at the virtual viewpoint from stereo images using the belief propagation method. This method needs only one disparity map, compared to the conventional methods that need two disparity maps. In the view synthesis part, we warp pixels from the reference images to the virtual viewpoint image using the disparity map at the virtual viewpoint. For real-time acceleration, we utilize a high speed GPU parallel programming, called CUDA. As a result, we can interpolate virtual viewpoint images in real-time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.289-296
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• 2016

This study presents the kinematics of an intrinsic continuum robot actuated by pneumatic artificial muscles. The single section of a developed continuum robot consisted of three muscles in parallel. The contraction of each muscle according to applied air pressure produced spatial motions of a distal plate with respect to a base plate. Based on the bending behaviors of artificial muscles, the orientation and position of the end-effector of a continuum robot were formulated using a transformation matrix. The orientation and position was also determined for a single section of the distal plate. A Jacobian matrix relating the contraction rate or the pressure rate of the muscles to the velocity vector of the end-effector was calculated considering the assembled position of actuators between neighboring sections of the robot. Experimental results showed that the motions of the intrinsic continuum robot were accurately estimated by the proposed kinematics.