• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.307-312
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• 2002

Among the various zero suppression (ZS) algorithms used in a for synchronous stream cipher system, a ZS-2 exhibits certain good properties, including the omission of the block synchronization, easy implementation, etc., yet also a weakness in channel error propagation. Accordingly, This paper proposes a new method by minimizing the bit-wide substitution in the substitution blocks of ZS-2 to improve the degenerated error property in a noisy channel. As a result, the proposed ZS-3 algorithm can decrease the mean error propagation by about 18.7% over that of ZS-2 at n=8.

• The KSFM Journal of Fluid Machinery
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• v.19 no.4
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• pp.54-62
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• 2016

This study presents an approach of tidal farming optimization using a numerical modelling method to simulate tidal energy extraction for 1MW scale tidal stream devices around Jangjuk-sudo, South Korea. The utility of the approach in this research is demonstrated by optimizing the tidal farm in an idealized scenario and a more realistic case with three scenarios of 28-turbine centered tidal array (named A, B and C layouts) inside the Jangjuk-sudo. In addition, the numerical method also provides a pre-processing calculation helps the researchers to quickly determine where the best resource site is located when considering the position of the tidal stream turbine farm. From the simulation results, it is clearly seen that the net energy (or wake energy yield which includes the impacts of wake effects on power generation) extracted from the layout A is virtually equal to the estimates of speed-up energy yield (or the gross energy which is the sum of energy yield of each turbine without wake effects), up to 30.3 GWh/year.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.587-596
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• 2004

During recent years, a new framework, which aims to bring a unified and global approach in indexing, browsing and querying various digital multimedia data such as audio, video and image has been developed. This new system partitions each media stream into smaller units based on actual physical events. These physical events within oath media stream can then be effectively indexed for retrieval. In this paper, we present a new approach that exploits audio, image and video features to segment and analyze the audio-visual data. Integration of audio and visual analysis can overcome the weakness of previous approach that was based on the image or video analysis only. We Implement a web-based multi media data retrieval system called XCRAB and report on its experiment result.

• Journal of KIISE:Databases
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• v.35 no.1
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• pp.1-16
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• 2008

Join queries having heavy cost are necessary to Data Stream Management System in Sensor Network where plural short information is generated. It is reasonable that each join operator has a sliding-window constraint for preventing DISK I/O because the data stream represents the infinite size of data. In addition, the join operator should be able to take multiple inputs for overall results. It is possible for the MJoin operator with sliding-windows to do so. In this paper, we consider the data stream environment where multiple MJoin operators are registered and propose MMJoin which deals with issues of building and processing a globally shared query considering characteristics of the MJoin operator with sliding-windows. First, we propose a solution of building the global shared query execution plan. Second, we solved the problems of updating a window size and routing for a join result. Our study can be utilized as a fundamental research for an optimization technique for multiple continuous joins in the data stream environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.569-579
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• 2013

Robot control and image processing using a smartphone and Wi-Fi communication is introduced. The robot has a wheel and quadruped mechanism that is transformed according to the environment and is mainly used for drug bottle delivery. The captured image on the camera is transmitted to the smartphone in the form of stream data, and the image data is processed in the smartphone to enable the robot to identify an object and to control the robot itself. A network was constructed so that only image data from the stream data was used, and an image processing scheme to identify the drug bottle and deliver it to a person using a robot arm is also presented. In this study, image processing techniques and algorithms were purely implemented on a smartphone with considerable computational power and multiple functions rather than a computer, which contributes to the intelligence and miniaturization of the robot system.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.797-800
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• 2016

IoT가 다양한 형태로 IT 기술을 이용하는 사물의 서비스를 제공하고 있다. 보다 스마트한 IoT 환경을 만들기 위하여 센서 데이터를 효율적으로 컨트롤하는 시스템이 필요하다. 본 논문은 계속적으로 생성되는 IoT 센서 데이터 를 효율적으로 처리하는 시스템을 Loosely Coupled 하고 확장 가능한 Sensor Reaction System의 아키텍처로 구성하고 있다. 본 논문에서는 Node.js, MQTT, MongoDB 기술을 사용함으로써 이벤트 기반한 stream 및 batch 처리를 할 수 있도록 센서 데이터를 메시지 큐에서 효율적으로 처리한다. 본 논문에서는 아두이노 보드에 온도 및 빛 센서를 부착한 센서 디바이스로부터 센서 테이터를 받아서 PC 기반의 MQTT Broker / Sensor Reactor / MongoDB 서버 시스템을 구축하고 성능을 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.707-710
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• 2004

In the case of terrestrial DMB(Digital Multimedia Broadcasting) system that offers mobile multimedia broadcasting services, transmission error must be considered. Although DMB transmission system provides the error protection functions of convolution coding and Reed-Solomon (204,188,t=8) coding, additional error resilience video coding methods are needed to satisfy the requirement of BER lower than $10^{-8}$. In this thesis, we propose and evaluate effective error resilience coding schemes using the MPEG-4 redundant slice for MPEG-4 video services in the DMB environment. In this scheme, we analyze the drift error caused by transmission error based on the random noise concept and the redundant slice selection algorithm that selects the most influential slice in the view of the drift error increment.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.685-689
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• 2023

The proposed system in the study aims to detect forest fires in real-time stream data received from the drone-camera. Recently, the number of wildfires has been increasing, and also the large scaled wildfires are frequent more and more. In order to prevent forest fire damage, many experiments using the drone camera and vision analysis are actively conducted, however there were many challenges, such as network speed, pre-processing, and model performance, to detect forest fires from real-time streaming data of the flying drone. Therefore, this study applied image data processing works to capture five good image frames for vision analysis from whole streaming data and then developed the object detection model based on YOLO_v2. As the result, the classification model performance of forest fire images reached upto 93% of accuracy, and the field test for the model verification detected the forest fire with about 70% accuracy.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.718-720
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• 2008

In this paper, the study focus on continuous query in EPC Information Services(EPCIS) middleware which is a component of RFID system. We can consider EPCIS as a data stream system with a repository. In our work continuous query is implemented in two query execution model. One is standing query model another is traditional query execution model in which continuous query run over database periodically. Furthermore a balance strategy is presented. It is used to determine which continuous query implementation model is suitable for the query. Finally we conclude our work and issue some research topic for future work.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.579-582
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• 2007

최근 들어 더욱 UCC(User Created Contents)등과 같은 대용량 멀티미디어(multimedia) 서비스에 대한 요구가 나날이 증가되면서 부하분산에 중점을 둔 웹 클러스터링 시스템(Web Clustering System) 에서 기존의 작은 크기의 스트림 데이터(Stream Data)나 조금 더 다양한 데이터를 위한 읽기 성능을 대용량 데이터에 초점을 맞춘 방안으로 최적화 시키는 것이 중요시되고 있다. 본 논문에서는 대용량 멀티미디어를 중심으로 실제 서비스시 간과 되어질 수 있는 운영체제(Operating System, O/S)에서의 I/O 인식, 디스크 제어 프로그램에서의 I/O, 웹 클러스터의 부하분산정책의 파라미터(Parameter)를 개선함으로써 읽기성능 향상 방안을 제시한다.