• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.9-16
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• 2004

This paper provides an observer-based Η$\infty$ output feedback controller design method for descriptor systems with time-varying delay by just one LMI(linear matrix inequality) condition. The sufficient condition for the existence of controller and the controller design method are presented by perfect LMI approach which can be solved efficiently by convex optimization. The design procedure involves solving an LMI. Since the obtained condition can be expressed as an LMI form all variables including feedback gain and observer gain can be calculated simultaneously by Schur complement changes of variables, and singular value decomposition. Moreover, The proposed controller design algorithm can be extended to the observer-based robust Η$\infty$ output feedback controller design method for descriptor systems with parameter uncertainty and time delay. An example is given to illustrate the results.

• 전자공학회논문지 IE
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• v.43 no.2
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• pp.80-86
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• 2006

The wireless communication based on LDPC and adaptive spatial-subcarrier coded modulation using MQAM for orthogonal frequency division multiplexing (OFDM) wireless transmission by using instantaneous channel state information and employing multiple antennas at both the transmitter and the receiver. Adaptive coded modulation is a promising idea for bandwidth-efficient transmission on time-varying, narrowband wireless channels. On power limited Additive White Gaussian Noise (AWGN) channels, low density parity check (LDPC) codes are a class of error control codes which have demonstrated impressive error correcting qualities, under some conditions performing even better than turbo codes. The paper demonstrates OFDM with LDPC and adaptive modulation applied to Multiple-Input Multiple-Output (MIMO) system. An optimization algorithm to obtain a bit and power allocation for each subcarrier assuming instantaneous channel knowledge is used. The experimental results are shown the potential of our proposed system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.646-652
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• 2016

This paper presents a tumor detection for breast cancer that utilizes two-dimensional(2D) image reconstruction with microwave tomographic imaging. The breast cancer detection system under development consists of 16 transmit/receive antennas, and the microwave tomography system operates at 1,700 MHz. The four types of breast(ED-, HD-, SC-, and FT-type) are used for image reconstruction. To solve a 2D inverse scattering problem, the method of moments(MoM) is employed for forward problem solving, and the simplex method employed as an optimization algorithm. The results of the reconstructed image show that the ED- and HD-types of breasts are well reconstructed, but SC- and FT-type breasts are not well because of the error including.

• Journal of Broadcast Engineering
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• v.17 no.5
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• pp.765-780
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• 2012

In this paper, we propose a fast mode decision method that determines the coding unit depth for enhancement layers to improve an encoding speed of a scalable video encoder based on HEVC. To decide the coding unit depth of the enhancement layer, firstly, the coding unit depth of the corresponded coding unit in the basement layer is employed. At this stage, the final CU depth is decided by calculating the rate-distortion costs of one lower depth to one upper depth of the referenced depth. The proposed method can reduce a computational load since it does not calculate the rate-distortion costs for all the depths of a target CU. We found that the proposed algorithm decreases encoding complexity of 26% with approximately 1.4% bit increment, compared with the simulcast encoder of the HM 4.0.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.46-53
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• 2012

The traffic in research network for the new structure of the network and new service research has the various properties. From the perspective of a specific traffic point of view, transmission of traffic with different requirements using a single routing protocol is an obstacle to satisfy requirements. In this study, we classify the properties of the traffic into two types. We propose the way that we can get the overall optimization effect, the experiment proves it by providing independent multiple forwarding path by applying optimized algorithm by types. In order to distinguish each type of traffic we use the ports on the switch and in order to implement independent path we apply OpenFlow system. In other words, we present the measure that can be implemented to improve the satisfaction of the traffic by making multiple paths by OpenFlow controller according to the type of traffic and by enforcing in Forwarder.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.150-153
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• 2002

High dose rate (HDR) brachytherapy in the treatment of cervix carcinoma has become popular, because it eliminated many of the problems with conventional brachytherapy. In order to improve clinical effectiveness with HDR brachytherapy, dose calculation algorithm, optimization procedures, and image registrations should be verified by comparing the dose distributions from a planning computer and those from a humanoid phantom irradiated. Therefore, the humanoid phantom should be designed such that the dose distributions could be quantitatively evaluated by utilizing the dosimeters with high spatial resolution. Therefore, the small size of thermoluminescent dosimeter (TLD) chips with the dimension of 1/8" and film dosimetry with spatial resolution of <1mm used to measure the radiation dosages in the phantom. The humanoid phantom called a pelvic phantom is made of water and tissue-equivalent acrylic plates. In order to firmly hold the HDR applicators in the water phantom, the applicators are inserted into the grooves of the applicator supporters. The dose distributions around the applicators, such as Point A and B, can be measured by placing a series of TLD chips (TLD-to- TLD distance: 5mm) in three TLD holders, and placing three verification films in orthogonal planes.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.67-75
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• 2013

The advantages of the orthogonal frequency division multiplexing (OFDM) are high spectral efficiency, resiliency to RF interference, and lower multi-path distortion. To further utilize vast channel capacity of the multiuser OFDM, one has to find the efficient adaptive subchannel and bit allocation among users. In this paper, we compare the performance of the linear programming dual of the 0-1 integer programming formulation with the existing convex optimization approach for the optimal subchannel and bit allocation problem of the multiuser OFDM. Utilizing tight lower bound provided by the LP dual formulation, we develop a primal heurisitc algorithm based on the LP dual solution. The performance of the primal heuristic is compared with MAO, ESA heuristic solutions, and integer programming solution on MATLAB simulation on a system employing M-ary quadrature amplitude modulation (MQAM) assuming a frequency-selective channel consisting of three independent Rayleigh multi-paths.

• Journal of IKEEE
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• v.10 no.1 s.18
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• pp.75-86
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• 2006

The MANET that can make autonomous distributed Network with Routing function has many differences than past wireless communication. For upcoming ALL-IP environment, MANET device should be connected with wired Internet Network and MANET is required to have a gateway to bridge two different networks to share information from any place. In this paper, Using the GMAHN Algorithm proposed Proactive, Reactive, Hybrid method that provides Inteface between Wired Internet network and MANET, we learned each method's the advantage and disadvantage through the various network environments. And also, we presented the optimization method of Hybrid combined Proactive with Reactive.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.5
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• pp.26-33
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• 2002

The design method of robust $H_{\infty}$ filtering for discrete-time uncertain linear systems is investigated in this paper. The uncertain parameters are assumed to be unknown but belonging to known convex compact set of polytope type. The objective is to design a stable robust $H_{\infty}$ filter guaranteeing the asymptotic stability of filtering error dynamics and present an $L_2$ induced norm bound analytically for the modified $H_{\infty}$ performance measure. The sufficient condition for the existence of robust $H_{\infty}$ filter and the filter design method are established by LMI(linear matrix inequality) approach, which can be solved efficiently by convex optimization. The proposed algorithm is checked through an example.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.4
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• pp.86-97
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• 2011

This paper presents a novel algorithm to detect more accurate road lane with image sensor-based color classification and directional edge clustering. With treatment of road region and lane as a recognizable color object, the classification of color cues is processed by an iterative optimization of statistical parameters to each color object. These clustered color objects are taken into considerations as initial kernel information for color object detection and recognition. In order to improve the limitation of object classification using the color cues, the directional edge cures within the estimated region of interest in the lane boundary (ROI-LB) are clustered and combined. The results of color classification and directional edge clustering are optimally integrated to obtain the best detection of road lane. The characteristic of the proposed system is to obtain robust result to all real road environments because of using non-parametric approach based only on information of color and edge clustering without a particular mathematical road and lane model. The experimental results to the various real road environments and imaging conditions are presented to evaluate the effectiveness of the proposed method.