• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.4
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• pp.422-429
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• 1988

The photoconductive multilayer of Se-As(hole blocking layer)/Se-As-Te (photoconductive layer) /Se-As (layer for supporiting hole transport)/Se-As(layer or controlling total capacitance)/Sb2S3(electron blocking layer) was fabricated and its electrical and optical properties were investigated. The photoconductive multilayer is made of evaporated a-Se as the base material, doped with As and Te to prevent the crystallization of a-Se and to enhance red sensitivity, respectively. The multilayer with good image reproducibility has the following deposition condition. The first layer has the thickness of 250\ulcornerat the deposition rate of 250\ulcornersec. The second layer has the thickness of 800\ulcornerat the deposition rate of 250\ulcornersec. The third layer has the thickness of 125\ulcornerat the deposition rate of 250\ulcornersec. The fourth layer has the thickness of 1700\ulcornerunder the Ar gas ambient of 50x10**-3torr. The image pick-up tube, employing this multilayer demonstrates the following characteristics. The photosensitivity is 0.8, the resolution limit is above 300TV line, and the decay lag is about 7%. And spectral response convers the whole visible range. Therfore the application to color TV camera is expected.

• Journal of Korea Multimedia Society
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• v.22 no.11
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• pp.1269-1279
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• 2019

In medical image analysis, segmentation is considered as a vital process since it partitions an image into coherent parts and extracts interesting objects from the image. In this paper, we consider automatic segmentations of OCT retinal images to find six layer boundaries using convolutional neural networks. Segmenting retinal images by layer boundaries is very important in diagnosing and predicting progress of eye diseases including diabetic retinopathy, glaucoma, and AMD (age-related macular degeneration). We applied well-known CNN architecture for general image segmentation, called Segnet, U-net, and CNN-S into this problem. We also proposed a shortest path-based algorithm for finding the layer boundaries from the outputs of Segnet and U-net. We analysed their performance on public OCT image data set. The experimental results show that the Segnet combined with the proposed shortest path-based boundary finding algorithm outperforms other two networks.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.1
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• pp.46-53
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• 2012

The WBAN technology means a short distance wireless network which provides each device's interactive communication by connecting devices inside and outside of body located within 3 meters. Standardization on the physical layer, data link layer, network layer and application layer is in progress by IEEE 802.15.6 TG BAN. It is necessary to develop the WBAN core technology that sensor node device, WBAN middleware and WBAN application service for WBAN environment. In this paper we designed the medical message structure and implemented medical application for purpose of vital information reliability. The message structure was proposed for WBAN environment and application can be check biometric information from BN on smart device through WBAN gateway.

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.267-274
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• 2016

PURPOSE. This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI). MATERIALS AND METHODS. Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (${\alpha}$=.05). RESULTS. Bond strength was significantly lower in untreated specimens than in sandblasted specimens (P<.05). No difference between the glaze layer and hydrofluoric acid application treated groups were observed. However, bond strength for these groups were significantly higher as compared with the other two groups (P<.05). CONCLUSION. Combined use of glaze layer & hydrofluoric acid application and silanization are reliable for strong and durable bonding between indirect composite material and monolithic zirconia.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.632-644
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• 2019

The remote monitoring and warning system for dangerous chemicals is designed with the concept of the Cyber-Physical System (CPS) in this paper. The real-time perception, dynamic control, and information service of major hazards chemicals are realized in this CPS system. The CPS system architecture, the physical layer and the applacation layer, are designed in this paper. The terminal node is mainly composed of the field collectors which complete the data acquisition of sensors and video in the physical layers, and the use of application layer makes CPS system safer and more reliable to monitor the hazardous chemicals. The cloud application layer completes the risk identification and the prediction of the major hazard sources. The early intelligent warning of the major dangerous chemicals is realized and the security risk images are given in the cloud application layer. With the CPS technology, the remote network of hazardous chemicals has been completed, and a major hazard monitoring and accident warning online system is formed. Through the experiment of the terminal node, it can be proved that the terminal node can complete the mass data collection and classify. With this experiment it can be obtained the CPS system is safe and effective. In order to verify feasible, the multi-risk warning based on CPS is simulated, and results show that the system solves the problem of hazardous chemicals enterprises safety management.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.419-428
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• 2004

Due to the deployment problem of the IP Multicast service, the Application Layer Multicast (or Overlay Multicast) has appeared as an alter-native of the If Multicast. However, even though plenty of the Application Layer Multicast (ALM) Protocols were designed and their applications were developed according to the diverse requirements of each multicast service, researches on the ALM Protocols are focused on only a protocol design or an efficient multicast group management algorithm. And there is little effort to provide a unified guideline for development of the ALM Protocols and provide an environment for running multiple protocols simultaneously in a system. In this paper, we propose socket APIs to be a reference in developing new ALM Protocols which enables a system to support multiple protocols in a system with other ALM Protocols and which gives an environment to support efficient protocol management.

• Journal of Power Electronics
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• v.9 no.2
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• pp.308-319
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• 2009

An increasing number of power electronic applications require high power density. Therefore, the switching frequency and switching speed have to be raised considerably. However, the very fast switching transients induce a strong voltage and current ringing. In this work, a novel damping concept is introduced where the parasitic wiring inductances are advantageously magnetically coupled with a damping layer for attenuating these unwanted oscillations. The proposed damping layer can be implemented using standard materials and printed circuit board manufacturing processes. The system behavior is analyzed in detail and design guidelines for a damping layer with optimized RC termination network are given. The effectiveness of the introduced layer is determined by layout parasitics which are calculated by application of the Partial Element Equivalent Circuit (PEEC) simulation method. Finally, simulations and measurements on a laboratory prototype demonstrate the good performance of the proposed damping approach.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.39-52
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• 2011

An application-layer attack can effectively achieve its objective with a small amount of traffic, and detection is difficult because the traffic type is very similar to that of legitimate users. We have discovered a unique characteristic that is produced by a difference in client intention: Both a legitimate user and DDoS attacker establish a session through a 3-way handshake over the TCP/IP layer. After a connection is established, they request at least one HTTP service by a Get request packet. The legitimate HTTP user waits for the server's response. However, an attacker tries to terminate the existing session right after the Get request. These different actions can be interpreted as a difference in client intention. In this paper, we propose a detection algorithm for application layer DDoS attacks based on this difference. The proposed algorithm was simulated using traffic dump files that were taken from normal user networks and Botnet-based attack tools. The test results showed that the algorithm can detect an HTTP-Get flooding attack with almost zero false alarms.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.225-227
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• 2009

International standard specification, H.264/SVC improved from H.264/AVC, is set up so as to promote free use of huge multimedia data in various channel environments.;H.264/AVC is a international standard speicification for video compression, adopted and commercialized as standard for DMB broadcasting by JVT of ISO/IEC MPEG and ITU-T VCEG. SVC standard uses 'intra/inter prediction' in AVC as well as 'inter-layer intra prediction', 'inter-layer motion prediction' and 'inter-layer residual prediction' to improve efficiency of encoding. Among prediction technologies, 'inter-layer intra prediction' is to use co-located block of up sampled sublevels as a prediction signal. At this time, application of interpolation is one of the most important factors to determine encoding efficiency. SVC's currently using poly-phase FIR filter of 4-tap and 2-tap respectively to luma components. This paper is written for the purpose of analyzing encoding performance according to the interpolation. For this purpose, we applied poly-phase FIR filter of '2-tap', '4-tap' and '6-tap' respectively to luma components and then measured bit-rate, PNSR and running time of interpolation filter. We're expecting that the analysis results of this paper will be utilized for effective application of interpolation filter. SVC standard uses 'intra/inter prediction' in AVC as well as 'inter-layer intra prediction', 'inter-layer motion prediction' and 'inter-layer residual prediction' to improve efficiency of encoding.

• 한국전기화학회:학술대회논문집
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• 2003.11a
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• pp.195-206
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• 2003