• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.10a
• /
• pp.210-214
• /
• 2004

This study proposes a design method for blade pitch control mechanism in order to regulate the power and to improve the starting characteristic. This power control unit which is assembled by spring and mass is planing to equip with 1kW class wind turbine system which is developed for low wind speed area like Korea. For the design of this control unit, the proper geometry of the hub was designed and the calculation of the mechanics was carried out. Especially, It is expected that the operational efficiency will be improved because of additional high pitch starting function by using 2 step spring structure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.61-65
• /
• 2011

In this paper, the nozzle design with asymmetric configuration using the optimal method is used in order to improve the under- and over-expansion problem of the flow at the supersonic turbine nozzle. For the design of nozzle contour, 8 design variables are selected and the total-to-static efficiency from the nozzle inlet to the wake outlet is considered as the objective function to be maximized. The Fluent6.3 and the iSIGHT-FD program are used for calculation of nozzle flow and design optimization respectively. RBF(Radial Basis Function) method is chosen for approximate optimization algorithm. It is shown that the static efficiency of improved nozzle design increases 1.35% and loss coefficient decreases 19.85% as compared to baseline design.

• Journal of Internet Computing and Services
• /
• v.23 no.2
• /
• pp.79-86
• /
• 2022

This paper focuses on realizing design improvement and high quality through visualization of reverse engineering-based software. As new technologies and complex software emerge in various areas of the fourth industry in the future, software verification with both stability and reliability is becoming an issue. We propose a reverse engineering-based UML design extraction and visualization for high-quality software ranging from simple computational software to machine learning-based data-oriented software. Through this study, it is expected to improve software quality through design improvement by checking the accuracy of the target design and identifying the code complexity.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.30 no.2
• /
• pp.108-114
• /
• 2002

In this paper, nonlinear finite element analysis is performed to ensure structural safety and to suggest the design improvement of wing-to-fuselage joint of the KSR-III rocket. In the joint, wings are attached to fuselage by fitting wing attachment part into the groove on the fuselage frame, and load transfer between wing and fuselage frame is accomplished mainly throug the contact of two members as well as fastening bolts. The careful finite element modeling has been proposed for the purpose of analyzing problems with relatively complicated load path. The detailed bolt modeling is conducted and GAP elemets are used to simulate contact problem between joined members and bolts. The suggested design improvement is verified by structural testing and the analysis results are compared with test results.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.1
• /
• pp.28-35
• /
• 2007

In this paper, an ultra low voltage SRAM design method based on dual-boosted cell bias technique is described. For each read/write cycle, the wordline and cell power node of the selected SRAM cells are boosted into two different voltage levels. This enhances SNM(Static Noise Margin) to a sufficient amount without an increase of the cell size, even at sub 1-V supply voltage. It also improves the SRAM circuit speed owing to increase of the cell read-out current. The proposed design technique has been demonstrated through 0.8-V, 32K-byte SRAM macro design in a $0.18-{\mu}m$ CMOS technology. Compared to the conventional cell bias technique, the simulation confirms an 135 % enhancement of the cell SNM and a 31 % faster speed at 0.8-V supply voltage. This prototype chip shows an access time of 23 ns and a power dissipation of $125\;{\mu}W/Hz$.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.11
• /
• pp.2653-2660
• /
• 2013

Representative sleep disorders represent sleep apnea and snoring. Although researches to diagnose sleep disorders as solutions for these problems are going on, the original researches only diagnose and measure sleep disorders but ones to find out the reasons are not activated much. Therefore, to reinforce this, this paper suggests sleep disorder improvement system based on multi-sensor. To design the system proposed in this paper, the entire system's structure was found and data's flow was planned. To ensure that the system works, mobile application and user interface was built based on Android. To test the results on accuracy of sleep disorders improvement system based on ontology using multi sensor built and planned in this paper, a scenario was written. As a result of testing inference results' accuracy changing factor values of sleep disorders following test scenario, proposed sleep disorders improvement system's accuracy was checked.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.1023-1028
• /
• 2007

It is the most important thing of the overall VE that we create inventive ideas from idea phase in the design VE. However, it is hard that it take a long time and create a superior idea using Brainstorming. And, it was real to lodge an alternative plan proposed on the idea thinking phase, it is true that an alternative plan of existing simply costdown apply to a change and insert isn't different from an inventive idea deduction. Also creating alternative idea, many expert hold on to only his field and it was exposed a limit depend on a team's experience or intuition than technical solution. In this study, we analyzed the problem of the present design VE processing and analyzed the problem through a survey to an expert, and then we'll suggest a possibility for an efficient design VE.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.3
• /
• pp.280-288
• /
• 2009

In this paper, a high-power and low-loss stripline 10-way power divider is designed and fabricated fur the feed network of an S-band linear array antenna with Chebyshev current distribution which has a narrow beam width and low side lobe level(SLL) of 35 dB or more. The unit cell of the power divider is based on a T-junction power divider and the whole divider is comprised of the cascaded unit cells. The multi-stage impedance transformer and modified ring hybrid are used in designing the power divider for performance improvement. And the reflection loss and insertion loss are improved by modifying a connector structure for a coaxial-to-stripline transition.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.11
• /
• pp.1462-1467
• /
• 2018

A number of algorithms for improving the image quality of low light images have been studied using a single image or multiple exposure images. The low light image is low in contrast and has a large amount of noise, which limits the identification of information of the subject. This paper proposes the hardware design of algorithms that improve the quality of low light image using 2 multiple exposure images taken with a dual camera. The proposed hardware structure is designed in real time processing in a way that does not use frame memory and line memory using transfer function. The proposed hardware design has been designed using Verilog and validated in Modelsim. Finally, when the proposed algorithm is implemented on FPGA using xc7z045-2ffg900 as the target board, the maximum operating frequency is 167.617MHz. When the image size is 1920x1080, the total clock cycle time is 2,076,601 and can be processed in real time at 80.7fps.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3A
• /
• pp.485-496
• /
• 2006

Practical stability design method of main members of cable-stayed bridges is proposed and discussed through a design example. For this purpose, initial tensions of stay cables and axial forces of main members are firstly determined using initial shaping analysis of bridges under dead loads. And then the effective buckling length using system elastic/inelastic buckling analysis and bending moments considering $P-{\delta}-{\Delta}$ effect by second-order elastic analysis are calculated for main girder and pylon members subjected to both axial forces and moments, respectively. Particularly, three load combinations of dead and live loads, in which maximum load effects due to live loads are obtained, are taken into account and effects of live loads on effective buckling lengths are investigated.