• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.5
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• pp.454-457
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• 2004

Partial response maximum likelihood (PRML) is a powerful and indispensable detection scheme for perpendicular magnetic recording channels. The proposed method is a low complexity detection scheme which is related to the PRML system. The simulation results show that PR(1,2,3,4,3,2,1)ML and PR(l,2,3,3,2,1)ML using modulation encoding with R=2/3 have the most improved performance at K=3,4. However, in the case of K=3, R=2/3 PR(1,1,1,1)ML effectively reduces the complexity compared to PR(1,2,3,3,2,1), but it has L5dB performance degradation at most. In the case of K=4, R=l PR(1,2,2,1)ML has very low complexity compared to R=2/3 PR(l,2,3,4,3,2,1)ML. but it has about 2dB performance degradation at most.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.1
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• pp.47-54
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• 2012

Video contents in the mobile environment are processed with the low bit-rate relative to normal video contents due to the consideration of network traffic; hence, it is necessary to protect the copyright of the low bit-rate video contents. The algorithm for watermarking appropriate for the mobile environment should be developed because the performance of the mobile devices is much lower than that of personal computers. This paper suggested the invisible spread spectrum watermarking method to the low bit-rate video contents, considering the low performance of the mobile device in the M-Commerce environment; it also enables to track down illegal users of the video contents to protect the copyright. The robustness of the contents with watermark is expressed with the correlation of extraction algorithm from watermark removed or distorted contents. The results of our experiment showed that we could extract the innate frequencies of M-Sequence when we extracted M-Sequence after compressing the contents with watermark easily. Therefore, illegal users of the contents can be tracked down because watermark can be extracted from the low bit-rate video contents.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.409-418
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• 2014

The amount of data located in storage servers has dramatically increased with the growth in cloud and social networking services. Storage systems with very large capacities may suffer from poor reliability and long latency, problems which can be addressed by the use of a hybrid disk, in which mechanical and flash memory storage are combined. The Linux-based SSD(solid-state disk) uses a caching technique based on the DM-cache utility. We assess the limitations of DM-cache by evaluating its performance in diverse environments, and identify problems with the caching policy that it operates in response to various commands. This policy is effective in reducing latency when Linux is running in native mode; but when Linux is installed as a guest operating systems on a virtual machine, the overhead incurred by caching actually reduces performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.468-471
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• 2010

MOST150, which has a higher bandwidth than of MOST25, appears to satisfy the demand for the automotive infotainment system and to increase the multimedia processing capacity, and the various technology applications are required for the accomplishment of MOST150 development. The MOST25 network technology is being restrictively equipped with some of the car models but the problems with bandwidth and compatibility has arisen. In order to solve this, the MOST150 technology has been developed and further research is being carried out to apply the technology to the automobile industry. Thus, for the effective process of the Ethernet traffic in the realization of MOST150/Ethernet Gateway for automobile, we, in the research, shall analyse the Management Mapping method, including the MOST150's Isochronous channel, the MOST Ethernet Packet channel, and etc. and study the efficient algorithm.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.548-548
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• 2015

과거 1990년대에 인터넷 이용이 전 세계로 확산되면서 World Wide Web를 이용하여 다양한 웹 서비스 기술의 구현 및 유통은 현재에도 개발되고 있다. 일반적으로 오늘날의 서비스는 XML 및 인터넷을 통하여 웹 서비스로 구현한 응용프로그램간의 연동을 가능하게 하는 기반기술이다. 이는 단순 객체 접근 프로토콜(SOAP), 웹 서비스 기술 언어(WSDL), 전역 비즈니스 레지스트리(UDDI) 등의 표준 기술을 사용하여 네트워크에 연결된 다른 컴퓨터 간의 분산 컴퓨팅을 지원하는 소프트웨어 및 기술이다. 이러한 웹 서비스의 발전으로 웹 서비스의 성능이 웹 서비스 제공자의 성패를 좌우하게 되고, 제공하고 있는 웹 서비스에 대한 검증이 필요하게 되었다. 웹 서비스에 대한 검증은 미국 Bloor NA(Bloor Research-North America)에서 웹 서비스 아키텍처의 단점을 발표하여 서비스의 품질과 신뢰성 및 개선점에 대하여 제시되어 활발한 연구가 진행 중에 있다. 그러나 사용자 관점에서 웹 서비스의 성능을 측정하고, 단순한 서비스 제공자의 서비스 검증 목적만이 아닌 서비스 제공자의 성능을 서비스 사용자에게 제공하는 검증 방법에 관한 연구가 많지 않은 실정이다. 하천공간정보에 대하여 웹 서비스 방식 중 통신 프로토콜인 HTTP 등을 이용한 인터넷상의 메시지 교환을 가능하게 하는 통신 프로토콜인 SOAP 및 WWW와 같은 분산 하이퍼미디어 시스템을 위한 소프트웨어 아키텍처의 한 형식인 REST(Representational State Transfer)를 실행하여 이에 따른 검증 프로세스를 수립하였다. 하천공간정보 웹 서비스에 대한 테스트 시나리오는 응답시간, 임계성능, 이용가능성, 신뢰성 및 접근성에 대하여 검증하며 하나 이상의 웹 서비스들 간의 호환성 표준의 준수 여부와 상호 운용 가능 여부를 테스트 하는 상호운용성 테스트, 신뢰성 메시징 및 분산 환경에서의 트랜잭션 처리 성능을 검증하는 웹 서비스 프로세스 품질 테스트를 실시하는 방안을 도출하고자 한다.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.10
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• pp.411-420
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• 2019

Camera model identification has been a subject of steady study in the field of digital forensics. Among the increasingly sophisticated crimes, crimes such as illegal filming are taking up a high number of crimes because they are hard to detect as cameras become smaller. Therefore, technology that can specify which camera a particular image was taken on could be used as evidence to prove a criminal's suspicion when a criminal denies his or her criminal behavior. This paper proposes a deep learning model to identify the camera model used to acquire the image. The proposed model consists of four convolution layers and two fully connection layers, and a high pass filter is used as a filter for data pre-processing. To verify the performance of the proposed model, Dresden Image Database was used and the dataset was generated by applying the sequential partition method. To show the performance of the proposed model, it is compared with existing studies using 3 layers model or model with GLCM. The proposed model achieves 98% accuracy which is similar to that of the latest technology.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.80-83
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• 2009

The most popular communication protocol is those defined by the IEEE 802.11 WLAN to support broadband internet connection. The demand for real-time multimedia service is increasing through WLAN on the road. The Hand-off function of mobile terminal is essential to support mobility. But, the hand-off function of IEEE 802.11 WLANs has the latency up to 300ms, and recent research has focusing on channel scanning and reconnection to AP and certification process of AP. It is also the lack of consideration in related works that hand-off happens frequently when the mobile node is moving. This paper proposed the hand-off algorithm that guarantees high throughput and estimates the point which may occur hand-off using GPS information and RSSI. We implement the proposed hand-off function that achieves the best performance.

• Journal of Broadcast Engineering
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• v.26 no.2
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• pp.167-174
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• 2021

Recently, deep learning technology is widely used in various computer vision applications, such as object recognition, classification, and image generation. In particular, the deep learning-based super-resolution has been gaining significant performance improvement. Fast super-resolution convolutional neural network (FSRCNN) is a well-known model as a deep learning-based super-resolution algorithm that output image is generated by a deconvolutional layer. In this paper, we propose an FPGA-based convolutional neural networks accelerator that considers parallel computing efficiency. In addition, the proposed method proposes Optimal-FSRCNN, which is modified the structure of FSRCNN. The number of multipliers is compressed by 3.47 times compared to FSRCNN. Moreover, PSNR has similar performance to FSRCNN. We developed a real-time image processing technology that implements on FPGA.

• Fashion & Textile Research Journal
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• v.21 no.3
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• pp.277-287
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• 2019

This study analyzes the online issues of design innovation by a fashion creative director. The study selected fashion house Gucci as the main subject and analyzed social media posts. As for study methods, a social matrix program Textom 2.0 collected 13,014 nouns and adjectives using 'Gucci Collection' as a search keyword from Naver Blogs from March to August 2014 and from March to August 2016. Design related issues were derived through semantic network analysis using Ucinet6 and the NetDraw program. The results of the keyword frequency analysis showed that social media user interest for the Gucci collection increased based on the rapid increase in the number of posts from 1,064 to 2,126 after changing the fashion creative director. The results of visualization of semantic network analysis and content analysis also showed that the main issues related to the Gucci collection design changed after the replacement of the fashion creative director. The study found that issues formed around the product information worn by celebrities for promotion purposes during the 2014 period; however, during the 2016 period, issues were formed around 'vintage' and 'retro' runway concepts with design styles related to Alessandro Michele, the new creative director.

• Journal of Broadcast Engineering
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• v.24 no.2
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• pp.329-340
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• 2019

Recently, broadcasting technologies have evolved as high-quality AV services such as domestic terrestrial UHD(Ultra-High Definition) broadcasting have been increasing, and broadcasting standards have been newly defined. Also, as network technology develops, contents are consumed not only in the country but also the world. Accordingly, content insertion technology, which is a method of providing suitable contents in accordance with the national and local environments, will be needed. This paper proposes a content insertion service system model and synchronization scheme using ATSC(Advanced Television Systems Committee) 3.0 Event Signaling standard under heterogeneous network environment of broadcasting network and internet network based on transmission standard DASH(Dynamic Adaptive Streaming over HTTP)/ROUTE(Real time Object delivery Over Unidirectional Transport) and MMT(MPEG Media Transport) of terrestrial UHD broadcasting. It also verifies that the service operates in an environment that meets the broadcast standard.