• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.351-354
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• 2009

Distributed video coding (DVC) is a new coding paradigm that enables to exploit the statistics among sources only in decoder and to achieve extremely low complex video encoding without any loss of coding efficiency. Wyner-Ziv coding, a particular implementation of DVC, reconstructs video by correcting noise on side information using channel code. Since a good quality of side information brings less noise to be removed by the channel code, generation of good side information is very important for the overall coding efficiency. However, if there are complex motions among frames, it is very hard to generate a good quality of side information without any information of original frame. In this paper, we propose a method to enhance the quality of the side information using small amount of additional information of original frame in the form of hash. By decoder's informing encoder where the hash has to be transmitted, side information can be improved enormously with only small amount of hash data. Therefore, the proposed method gains considerable coding efficiency. Results of our experiment have verified average PSNR gain up to 1 dB, when compared to the well-known DVC codec, known as DISCOVER codec.

• Journal of Power Electronics
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• v.2 no.3
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• pp.181-188
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• 2002

The utility interfaced sinewave modulation Inverter for the solar photovoltaic power conditioner with a high frequency transformer is presented for residential applications. As compared with the conventional full-bridge hard switching slnewave PWM inverter with a high frequency link, the simplest single-ended edge-resonant soft switching sinewave inverter with a sinewave duty cycle pulse control scheme is implemented, resulting in size and weight reduction, low cost and high efficiency This paper presents a prototype system of the sinewave zero voltage soft switching sinewave inverter for solar power conditioner, along with its operating principle and unique features. In addition to these, this paper discusses a control implementation to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed and evaluated from an experimental point of view A newly developed utility-connected sinewave power conditioning circuit which achieves 92.5% efficiency under 4kW output is demonstrated.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.145-149
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• 2006

Building Information Modeling (BIM) is the process of integrating and re-using information generated and used throughout the lifecycle of a building. BIM may not be very different from other management methods in that it aims to minimize the economic loss and maximize the profit by designing, building, and maintaining a building better, faster, yet cheaper. The major difference between BIM and other methods is that BIM approaches the goal from a system point of view whereas other methods generally approaches the goal from a business management point of view. Since a project cannot succeed without considering both systematic and managerial aspects of a project, the line has been blurred these days. This paper explores a historical background of BIM and discusses the key technologies for successful implementation of BIM.

• Journal of Power Electronics
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• v.12 no.3
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• pp.377-386
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• 2012

An interleaved bridgeless buck-boost AC/DC converter is presented in this paper to achieve the characteristics of low conduction loss, a high power factor and low harmonic and ripple currents. There are only two power semiconductors in the line current path instead of the three power semiconductors in a conventional boost AC/DC converter. A buck-boost converter operated in the boundary conduction mode (BCM) is adopted to control the active switches to achieve the following characteristics: no diode reverse recovery problem, zero current switching (ZCS) turn-off of the rectifier diodes, ZCS turn-on of the power switches, and a low DC bus voltage to reduce the voltage stress of the MOSFETs in the second DC/DC converter. Interleaved pulse-width modulation (PWM) is used to control the switches such that the input and output ripple currents are reduced such that the output capacitance can be reduced. The voltage doubler topology is adopted to double the output voltage in order to extend the useable energy of the capacitor when the line voltage is off. The circuit configuration, principle operation, system analysis, and a design example are discussed and presented in detail. Finally, experiments on a 500W prototype are provided to demonstrate the performance of the proposed converter.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1361-1369
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• 2000

For the implementation of 3D Sound Localization system, the binaural filtering by HRTFs is generally employed. But the HRTF filter is of high order and its coefficients for all directions have to be stored, which imposes a rather large memory requirement. To cope with this, research works have centered on obtaining low dimensional HRTF representations without significant loss of information and synthesizing the original HRTF efficiently, by means of feature extraction methods for multivariate dat including PCA. In these researches, conventional linear PCA was applied to the frequency domain HRTF data and using relatively small number of principal components the original HRTFs could be synthesized in approximation. In this paper we applied neural network based nonlinear PCA model (NLPCA) and the nonlinear PLS repression model (NLPLS) for this low dimensional HRTF modeling and analyze the results in comparison with the PCA. The NLPCA that performs projection of data onto the nonlinear surfaces showed the capability of more efficient HRTF feature extraction than linear PCA and the NLPLS regression model that incorporates the direction information in feature extraction yielded more stable results in synthesizing general HRTFs not included in the model training.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1214-1218
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• 2010

A new compact UWB bandpass filter with sharp-rejection and low insertion-loss is designed in this paper, using the parallel transmission line with SIR structure. An Example filter is firstly theoretically designed by the proposed synthesis procedure, the optimized by EM simulator, fabricated in microstrip line and finally characterized by a network analyzer. A good agreement between the simulation results and prototype validates the proposed UWB bandpass filter. The designed filter also realized a sharp rejection of higher order with a relatively small size which is proper for the UWB communication system.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.6
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• pp.288-294
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• 2004

In this paper, a ceramic antenna and diplexer are designed for dual-band handset ap plications. Basically, the antenna is designed by using the meander line configuration. The diplexer presented in this paper is composed of both low- and high-pass filters. We have designed the low- and high-pass filters with attenuation poles to improve the attenuation performances of the diplexer. The attenuation poles are located at each rejection frequency region so as to improve the shrinkage characteristic of the diplexer. In order to accomplish the volume effectiveness, the antenna and the diplexer have been designed and fabricated in a multi-layer structure. The diplexer designed with a multi-layer structure has inductors and capacitors, which are implemented by LTCC (Low Temperature Co-fired Ceramics) process technique. Design of the multi-layer antenna and diplexer has been achieved by employing the full 3-D EM simulation. The designed antenna and diplexer offer excellent return loss and broadband performances with highly isolated rejection performance.

• New & Renewable Energy
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• v.16 no.2
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• pp.20-27
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• 2020

According to "The Renewable Energy 3020 Implementation Plan", offshore wind power accounts for 12 GW of the total new capacity of 48.7 GW. Like the south-west 2.5 GW offshore wind farm case, government-led development has had difficulty in securing the residents' acceptability. This study contributes to the study of local acceptance by analyzing the perceptions of Maldo residents. To this end, in-depth interviews were conducted with the head of a village and fishing village chief, and the entire contents of the interview were revised and analyzed. The cognitive structure of the stakeholders could be confirmed using semantic network analysis, which analyzes the network structure among words. Based on the analysis results, focusing on the identity frames related to the compensation process from previous national projects, gain vs. loss frames act as the dominant frame in terms of profits from offshore wind turbines. To invigorate offshore wind farms, the policy implications as follows. First, a negotiation organization should be organized to deal with strategic opposition by fishes. Second, installing offshore wind farms on a public water body will result in demands for compensation from various actors, and a licensed fishing territory as an offshore wind farm installation site should be considered.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1235-1242
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• 2006

Viscoelastic damping materials are widely used to reduce noise and vibration because of its low cost and easy implementation, for examples, on the body structure of passenger cars, air planes, electric appliances and ships. To design the damped structures, the material property such as elastic modulus and loss factor is essential information. The four-parameter fractional derivative model well describes the nonlinear dynamic characteristics of the viscoelastic damping materials with respect to both frequency and temperature with fewer parameters than conventional spring-dashpot models. However the identification procedure of the four-parameter is very time-consuming one. An efficient identification procedure of the four-parameters is proposed by using an FE model and a gradient-based numerical search algorithm. The identification procedure goes two sequential steps to make measured FRFs coincident with simulated FRFs: the first one is a peak alignment step and the second one is an amplitude adjustment. A numerical example shows that the proposed method is efficient and robust in identifying the viscoelastic material parameters of fractional derivative model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3182-3202
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• 2015

Flexibly expanding the storage capacity required to process a large amount of rapidly increasing unstructured log data is difficult in a conventional computing environment. In addition, implementing a log processing system providing features that categorize and analyze unstructured log data is extremely difficult. To overcome such limitations, we propose and design a MongoDB-based unstructured log processing system (MdbULPS) for collecting, categorizing, and analyzing log data generated from banks. The proposed system includes a Hadoop-based analysis module for reliable parallel-distributed processing of massive log data. Furthermore, because the Hadoop distributed file system (HDFS) stores data by generating replicas of collected log data in block units, the proposed system offers automatic system recovery against system failures and data loss. Finally, by establishing a distributed database using the NoSQL-based MongoDB, the proposed system provides methods of effectively processing unstructured log data. To evaluate the proposed system, we conducted three different performance tests on a local test bed including twelve nodes: comparing our system with a MySQL-based approach, comparing it with an Hbase-based approach, and changing the chunk size option. From the experiments, we found that our system showed better performance in processing unstructured log data.