• Journal of KIISE:Computer Systems and Theory
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• v.27 no.7
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• pp.684-694
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• 2000

For designing circuits for low power systems, the capacitance is an important factor for the power dissipation. Since the capacitance of a gate is proportional to the area of the gate, we can reduce the total power consumption of a circuit by reducing the total area of gates, where total area is a simple sum of all gate areas in the circuit. To reduce the total area, transistor resizing can be used. While resizing transistors, inserting buffer in the proper position can help reduce the total area. In this paper we propose two methods for concurrent transistor sizing and buffer insertion. One method uses template window simulation and the other uses extrapolation. Experimental results show that concurrent transistor sizing with buffer insertion achieved 10-20% more reduction of the total area than when it was done without buffer insertion and template window simulation is more efficient than extrapolation.

• Journal of Korean Association for Spatial Structures
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• v.7 no.4
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• pp.89-96
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• 2007

The fundamental frequency maximization of beam structures is carried out by using strain energy based topology optimization technique. It mainly uses the modal strain energy distributions induced by the mode shapes of the structures. The modal strain energy to be minimized is employed as the objective function and the initial volume of structures is adopted as the constraint function. The resizing algorithm devised from the optimality criteria method is used to update the hole size of the cell existing in each finite element. The beams with three different boundary conditions are used to investigate the optimum topologies against natural mode shapes. From numerical test, it is found to be that the optimum topologies of the beams produced by the adopted technique have hugh increases in some values of natural frequencies and especially the technique is very effective to maximize the fundamental frequency of the structures.

• Journal of Korean Association for Spatial Structures
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• v.5 no.3 s.17
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• pp.83-89
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• 2005

This paper provides the results of the investigation on the optimum topology of simply supported deep beam structures with multi-point load cases. In this study, the strain energy to be minimized is considered as the objective function and the initial volume of structures is used as the constraint function. The resizing algorithm based on the optimality criteria is adopted to update the hole size existing inside the material. In this study, the sensitivities of topology optimization parameters to the optimum topology of the deep bean structures is investigated and also the effect of filtering process on the optimum topology is thoroughly tested. From numerical tests, the optimum topology of the deep beam is closely related with the optimization parameters used in the iteration and the filtering process play important role in order to find the optimum topology of the deep beam.

• Journal of Korean Association for Spatial Structures
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• v.7 no.5
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• pp.67-74
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• 2007

The unsymmetrically layered artificial material model is consistently introduced to find the optimum topologies of the plate structures. Reissner-Mindlin (RM) plate theory is adopted to formulate the present 9-node plate element considering the first-order shear deformation of the plates. In the topology optimization process, the strain energy to be minimized is employed as the objective function and the initial volume of structures is adopted as the constraint function. In addition, the resizing algorithm based on the optimality criteria is used to update the hole size introduced in the proposed artificial material model. Several numerical examples are rallied out to investigate the performance of the proposed technique. From numerical results, the proposed topology optimization techniques are found to be very effective to produce the optimum topology of plate structures. In particular, the proposed unsymmetric stiffening layer model make it possible to produce more realistic stiffener design of the plate structures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10C
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• pp.1484-1489
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• 2004

Given a video frame in terms of its 8${\times}$8 block-DCT coefncients, we wish to obtain a downsized or upsized version of this Dame also in terms of 8${\times}$8 block DCT coefficients. The DCT being a linear unitary transform is distributive over matrix multiplication. This fact has been used for downsampling video frames in the DCT domains in Dugad's, Mukherjee's, and Park's methods. The downsampling and upsampling schemes combined together preserve all the low-frequency DCT coefficients of the original image. This implies tremendous savings for coding the difference between the original frame (unsampled image) and its prediction (the upsampled image).This is desirable for many applications based on scalable encoding of video. In this paper, we extend the earlier works to various DCT sizes, when we downsample and then upsample of an image by a factor of two. Through experiment, we could improve the PSM values whenever we increase the DCT block size. However, because the complexity will be also increase, we can say there is a tradeoff. The experiment result would provide important data for developing fast algorithms of compressed-domain image/video resizing.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.7
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• pp.100-106
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• 2015

In this paper, we propose a fast algorithm for low-power image enhancement method for mobile LCD. In the proposed fast algorithm, the spatial resolution of the input image is significantly reduced, and the image characteristics are analyzed on the reduced resolution image to find a dimming rate adaptive to the image content, thereby saving power. The proposed fast adaptive dimming and image enhancement algorithm is implemented as an application that runs on an Android device. Image quality evaluation and running time analysis experiments on the device indicate that the proposed fast algorithm jointly minimizes the quality degradation and power consumption, reducing the required computation load by over 95%.

• Composites Research
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• v.31 no.6
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• pp.299-303
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• 2018

In order to improve the interfacial bonding force and reaction polymerization degree of the carbon fiber reinforced nylon 6 composite material, the surface of the existing epoxy-sizing carbon fiber was desized to remove the epoxy and treated with urethane, nylon and phenoxy sizing agent, was observed. The interfacial bond strength of the resized carbon fiber was confirmed by IFSS (Interfacial Shear Strength) and the fracture surface was observed by scanning electron microscope. The results showed that the interfacial bonding strength of the carbon fiber treated with nylon and phenoxy sizing agents was higher than that of urethane - based sizing. It has been found that the urethane - type resizing carbon fiber has lower interfacial bonding strength than the conventional epoxy - sizing carbon fiber. This result shows that the interfacial bonding between carbon fiber and nylon 6 is improved by removing low activity and smoothness of existing carbon fiber.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.121-128
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• 2005

This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift for shear wall structures subject to lateral loads. To this end the displacement sensitivity depending on behavior characteristics of shear wall structures is established. Also, the approximation concept that can preserve the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Resizing sections in the stiffness-based optimal design are assumed to be uniformly varying in size and the technique of member grouping is considered for the improvement of construction efficiency Two types of 11-story shear wall structures are presented to illustrate the features of the quantitative lateral drift control technique proposed in this study.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.210-215
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• 2008

This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift and evaluates the structural behavior characteristics and efficiency for tall outrigger system subject to lateral loads. To this end, displacement sensitivity depending on behavior characteristics of outrigger system is established and approximation concept that can efficiently solve large scale problems is introduced. Specifically, under the 'constant-shape' assumption, resizing technique of member is developed. Two types of 60 story frameworks are presented to illustrate the features of the quantitative lateral drift control technique proposed in this study.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.511-514
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• 2000

디지털 워터마킹이란 디지털 컨텐츠의 저작권을 보호하기 위해 보이지 않는 임의의 데이터를 미디어에 삽입하는 방법이다. 본 논문에서는 주파수 영역으로 변환된 원 데이터를 임의의 방향으로 정의된 데이터와 내적(Inner Product)하여 이를 워터마크 정보에 따라 변화시키는 방법을 제안한다. 이 방법은 비밀키가 워터마크 데이터와 연관된 것이 아니기 때문에 어떠한 종류의 데이터도 삽입할 수 있다는 장점이 있다. 사용되는 비밀키는 주파수 영역으로 변환된 원 데이터와 내적되는 임의의 데이터를 만드는데 사용된다. 또한 워터마크의 견고성을 높이기 위해, 주파수 영역으로 변환된 원 데이터와 내적된 임의의 데이터는 잡음처럼 되므로 이를 인간 시각 특성을 사용하여 모델링 하였다. 제안된 방법은 원 영상 없이 워터마크를 검출할 수 있으며. 워터마크의 견고성 실험을 위해 JPEG, Cropping, Resizing. Gaussian 잡음 등을 적응하였다.