• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.761-765
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• 1995

The old Timing Controller for Control Element Drive Mechanism (CEDM) is designed as an open loop control system because it is difficult to mount sensors within the Control Element Drive Mechanism(CEDM) which is operating under the pressure boundary of the reactor vessel. In this work new method which can be used to detect the CEDM operational conditions without mounting sensors within the CEDM housing is developed in order to resolve problems of the old Timing Controller. By using the developed new method, the new Timing Controller for the CEDM is designed as a closed loop controller which has features of the control rod drop prevention, fine position control and the coil life time extension. The algorithm developed under closed loop control concept resolves most problems occurred in the old Timing Controller and improves the performance and reliability of the system. During designing and testing of the Timing Controller algorithm, the real time CEDM simulator developed here was used. And all functions of the developed algorithm were verified using CEDM simulator with the real data collected from the site. The results show that the Timing Controller performs its intended functions properly.

• International Journal of CAD/CAM
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• v.7 no.1
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• pp.71-80
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• 2007

Recently, feature-based solid modeling systems have been widely used in product design. However, for engineering analysis of a product model, an ed CAD model composed of mid-surfaces is desirable for conditions in which the ed model does not affect analysis result seriously. To meet this requirement, a variety of solid ion methods such as MAT (medial axis transformation) have been proposed to provide an ed CAE model from a solid design model. The algorithm of the MAT approach can be applied to any complicated solid model. However, additional work to trim and extend some parts of the result is required to obtain a practically useful CAE model because the inscribed sphere used in the MAT method generates insufficient surfaces with branches. On the other hand, the mid-surface ion approach supports a practical method for generating a two-dimensional ed model, even though it has difficulties in creating a mid-surface from some complicated parts. In this paper, we propose a dimension reduction approach on solid models based on the midsurface abstraction approach. This approach simplifies the solid model by abbreviating or removing trivial features first such as the fillet, mounting, or protrusion. The geometry of each face is replaced with mid-patches from the simplified model, and then unnecessary topological entities are deleted to generate a clean ed model. Also, additional work, such as extending and stitching mid-patches, completes the generation of a mid-surface model from the patches.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.29-37
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• 2000

Because the previous design procedure for the composite wind turbine blade structure using trial and error method takes long time, a improved design procedure by using the program based on classical laminate theory was proposed to reduce the inefficient element. According to the improved design procedure, limitation of strains, stresses and displacements specified by international standard specification IEC1400-1 for the composite wind turbine blade were applied to sizing the structural configuration by using the rule of mixture and the principal stress design technique with a simplified turbine blade. Structural safety for strength and buckling stability was confirmed by the developed analysis program based on the laminate theory to minimize the design procedure. After modifying the preliminary design result with additional structural components such as skin, foam sandwich and mounting joints, stresses, strains, displacements, natural frequency, buckling load and fatigue life were analyzed by the finite element method. Finally these results were confirmed by comparing with IEC1400-1 specification.

• Journal of Sensor Science and Technology
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• v.10 no.1
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• pp.16-23
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• 2001

Comparing with general optical fiber sensors performing localized measurement, distributed optical fiber sensors can measure along an optical fiber, and they have large measuring range. The surface-mounting method with epoxy adhesive is general in attaching optical fiber sensors to structures, This is also appliable to the structural integrity monitoring with Brillouin-scattering distributed optical fiber sensors. In this paper, Brillouin-scattering distributed optical fiber sensors, which are attached to the surface of a structure with epoxy adhesive, was verified with the finite element method. From the analysis results of strain transfer through the structure, optical fiber coating, cladding and core, the strain transfer rates were calculated. And the influence of the epoxy free-end was also studied.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.927-934
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• 2019

Recently, mobile devices have evolved into small computers with various functions according to user requirements. Careful attention must be paid to the design of the power supply network for the stable operation of the application processor (AP), the wireless communication modem, the high performance camera, and the various interfaces of the mobile device to implement various functions of the mobile device. In this paper, we analyzed and verified the method of optimizing the design parameters such as the position, capacity, and number of decoupling capacitors to meet the target impedance required by the driver IC chip to ensure the stability of the power supply network of mobile devices that should be designed as wiring type due to mounting density limitation. The proposed wired power supply network design method can be applied to various applications including high-speed signal transmission line in addition to mobile applications.

• Molecules and Cells
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• v.42 no.1
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• pp.87-95
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• 2019

Long interspersed element-1 (LINE-1 or L1) is an autonomous retrotransposon, which is capable of inserting into a new region of genome. Previous studies have reported that these elements lead to genomic variations and altered functions by affecting gene expression and genetic networks. Mounting evidence strongly indicates that genetic diseases or various cancers can occur as a result of retrotransposition events that involve L1s. Therefore, the development of methodologies to study the structural variations and interpersonal insertion polymorphisms by L1 element-associated changes in an individual genome is invaluable. In this study, we applied a systematic approach to identify human-specific L1s (i.e., L1Hs) through the bioinformatics analysis of high-throughput next-generation sequencing data. We identified 525 candidates that could be inferred to carry non-reference L1Hs in a Korean individual genome (KPGP9). Among them, we randomly selected 40 candidates and validated that approximately 92.5% of non-reference L1Hs were inserted into a KPGP9 genome. In addition, unlike conventional methods, our relatively simple and expedited approach was highly reproducible in confirming the L1 insertions. Taken together, our findings strongly support that the identification of non-reference L1Hs by our novel target enrichment method demonstrates its future application to genomic variation studies on the risk of cancer and genetic disorders.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1397-1402
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• 2021

The overlay2 file system is one of the union file systems that mounts multiple directories into one. The source directory used for this overlay2 file system mount has a characteristic that it operates independently of the write-able layer after mounting, so it is often used for container platforms for application delivery. However, the overlay2 file system has a security vulnerability that the write-able layer is also modified when file in the source directory is modified. In this study, I proposed the overlay2 file system protection technology to remove the security vulnerabilities of the overlay2 file system. As a result of empirically implementing the proposed overlay2 file system protection technology and verifying the function, the protection technology proposed in this study was verified to be effective. However, since the method proposed in this study is a passive protection method, a follow-up study is needed to automatically protect it at the operating system level.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.291-297
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• 2022

This Paper is about the study that design performance and reliability measurement circuits of the IPM which is an intelligent switching switch module included at an inverter circuits for driving of A.C. Servo motors in home appliance. IPM is a core device of motor driver and it's switching characteristics should be retained uniformly during the driving of a servo system. All of it's specification, the collector emitter switch on voltage Vce(on) spec. is very important. As the IPM are core part of inverters and producing from several brands and versions, for optimal performances of application systems a method and measurement & evaluation system to measure Vce(on) value, collector emitter switch on voltage, of the IPM IGBT switches with various brands are required. Especially, the proposed method can measure and evaluate Vce(on) values of IPM with load at mounting state on the motor driving circuits and proposed measurement & evaluation system can be important instrument systems for IPM user companies.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.237-242
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• 2023

Research on high-performance walking robots is being actively conducted, and quadruped walking robots are receiving a lot of attention due to their excellent mobility and adaptability on uneven terrain, but they are difficult to introduce and utilize due to high cost. In this paper, to increase utilization by applying intelligent functions to a low-cost quadruped robot, we present a method of improving uneven terrain overcoming ability by mounting IMU and reinforcement learning on embedded board and automatically detecting objects using camera and deep learning. The robot consists of the legs of a quadruped mammal, and each leg has three degrees of freedom. We train complex terrain in simulation environments with designed 3D model and apply it to real robot. Through the application of this research method, it was confirmed that there was no significant difference in walking ability between flat and non-flat terrain, and the behavior of performing person detection in real time under limited experimental conditions was confirmed.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3068-3073
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• 2007

Aerodynamic forces and moments have been used to control rocket propelled vehicles. If control is required at very low speed, Those systems only provide a limited capability because aerodynamic control force is proportional to the air density and low dynamic pressure. But thrust vector control(TVC) can overcome the disadvantages. TVC is the method which generates the side force and roll moment by controlling exhausted gas directly in a rocket nozzle. TVC is classified by mechanical and fluid dynamic methods. Mechanical methods can change the flow direction by several objects installed in a rocket nozzle exhaust such as tapered ramp tabs and jet vane. Fluid dynamic methods control the flight direction with the injection of secondary gaseous flows into the rocket nozzle. The tapered ramp tabs of mechanical methods are used in this paper. They installed at the rear in the rocket nozzle could be freely moved along axial and radial direction on the mounting ring to provide the mass flow rate which is injected from the rocket nozzle. In this paper, the conceptual design and the performance study on the tapered ramp tabs of the thurst vector control has been carried out using the supersonic cold flow system and shadow graph. Numerical simulation was also performed to study flow characteristics and interactions between ramp tabs. This paper provides to analyze the location of normal shock wave and distribution of surface pressure on the region enclosed by the tapered ramp tabs.