• Structural Engineering and Mechanics
• /
• v.58 no.2
• /
• pp.301-326
• /
• 2016

An optimization method of patch shape was developed in this study, in order to improve repair of cracked plates. It aimed to minimize three objectives: stress intensity factor, patch volume and shear stresses in the adhesive film. The choice of these objectives ensures improving crack repair, gaining mass and enhancing the adhesion durability between the fractured plate and the composite patch. This was a multi-objective optimization combined with Finite elements calculations to find out the best distribution of patch height with respect to its width. The implementation of the method identified families of optimal shapes with specific geometric features around the crack tip and at the horizontal end of the patch. Considerable mass gain was achieved while improving the repair efficiency and keeping the adhesive shear stress at low levels.

• The Journal of Korea Robotics Society
• /
• v.10 no.1
• /
• pp.16-23
• /
• 2015

This paper presents a method of improving the pose recognition accuracy of objects by using Kinect sensor. First, by using the SURF algorithm, which is one of the most widely used local features point algorithms, we modify inner parameters of the algorithm for efficient object recognition. The proposed method is adjusting the distance between the box filter, modifying Hessian matrix, and eliminating improper key points. In the second, the object orientation is estimated based on the homography. Finally the novel approach of Auto-scaling method is proposed to improve accuracy of object pose estimation. The proposed algorithm is experimentally tested with objects in the plane and its effectiveness is validated.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.3
• /
• pp.1113-1135
• /
• 2018

Existing trust evaluation models for wireless sensor networks can accurately and objectively evaluate trust value of nodes, but the nodes' energy saving problem was ignored. Especially when there are a few malicious nodes in a network, the overall trust value calculation for all nodes would waste lots of energy. Beside that, the network failure caused by nodes death was also not considered. In this paper, we proposed a method for avoiding energy hole which applied trust evaluation models and a trust evaluation method based on information entropy, so as to achieve the purpose of improving nodes utilization. Simulation results show that the proposed method can effectively improve nodes utilization, and it has reasonable detection rate and lower false alert rate compared to other classical methods.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.850-851
• /
• 2015

In this paper, it employs IPMSM sensorless methods about current model and Extend-EMF methods. By using a MATLAB/Simulink program, it presents sensorless method in relation No high frequency voltage and replaces current based sensorless method. This IPMSM motor is drived by MTPA and Flux weakening controls for adjusting a actual motor application. In order to improving stability of IPMSM sensorless control, method about Sensorless estimation change is suggested by this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.12
• /
• pp.4624-4642
• /
• 2014

Image compression is a popular research issue that focuses on the problems of reducing the size of multimedia files. Vector Quantization (VQ) is a well-known lossy compression method which can significantly reduce the size of a digital image while maintaining acceptable visual quality. A locally adaptive scheme (LAS) was proposed to improve the compression rate of VQ in 1997. However, a LAS needs extra indicators to indicate the sources, consequently the compression rate of LAS will be affected. In this paper, we propose a novel method to eliminate the LAS indicators and so improve the compression rate. The proposed method uses the concept of data hiding to conceal the indicators, thus further improving the compression rate of LAS. From experimental results, it is clearly demonstrated that the proposed method can actually eliminate the extra indicators while successfully improving the compression rate of the LAS.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.5
• /
• pp.463-470
• /
• 2005

This paper describes a method aimed at improving dead-reckoning accuracy with gyroscopes in mobile robots. The method is a precision calibration procedure for gyroscopes, which effectively reduces the ill effects of nonlinearity of the scale-factor and temperature dependency. This paper also describes the methods of gyro data collection fur all ambient temperature$(-40^{\circ}C{\~}+80^{\circ}C)$ using cubic spline interpolation and defining the error function. The sensor used was a vibrating gyroscope called the EWTS82NA21, which is low lost and commonly used in car navigation system, made by Panasonic. This angular rate sensor utilizes Coriolis force generated by a vibrating tuning fork. The paper also provides experimental results to check the performance and the effectiveness of the proposed method.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.295-297
• /
• 2013

Reinforcing bar coupling method has a variety of ways including lap-splice method. However, there are problems that need to be improved in terms of constructability, economics analysis. We should be improved about the problems of the existing methods. Accordingly, this study were developed a new type of staggered grip type reinforcing bar coupling. The proposed method show the following effects than existing methods. First, this method can be reduce time through improved workability. Second, increasing safety through the slip removal. Third, improving economic efficiency by reduce the manufacturing costs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.800-803
• /
• 2006

In this paper, we propose a method for improving the performance of the face recognition using a hybrid neural network. The propose method focused on improving face recognition technique using SOM and LVQ. In order to verify the effectiveness of the proposed method, we performed simulations on face database supplied ORL. The results show that the proposed method considerably improves on the performance of the eigenface, hidden markov model, multilayer neural network.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.291-294
• /
• 2005

This paper presents a method of improving performance of an electromagnetic clutch for the next generation tank gun. One of the most important things in the design of the clutch is to satisfy the requirement for the maximum torque even if the torque is varied. To achieve this requirement, it is needed to expand the operation range of the torque. Consequently, we have performed shape changes in order to cancel magnetic flux bottlenecks on the magnetic path. Simulation results from the finite element method show that the method proposed in this paper is proper for the clutch.

• Journal of the Korean Professional Engineers Association
• /
• v.33 no.1
• /
• pp.83-88
• /
• 2000

Taguchi developed and provided various independent methods for actual application in design of experiments. Taguchi method is described in philosophy, method and others related to quality management. This thesis is one of case studies for improving the bond strength of epoxy resin by Taguchi method which is applied as a optimum developing tool in six sigma management revolution in many companies.