• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.993-994
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• 2011

This paper presents the characteristic analysis of thermal behavior of a single-phase line-start permanent magnet motor(LSPM) for high-efficiency design. By analyzing of thermal behavior, it can consider demagnetization characteristics of permanent magnets. In addition, by calculating the allowable current density it will be able to reduce the size of the stator. For this reason single-phase LSPM is necessary to examine the thermal analysis. Thermal analysis was performed using heat source mapping, and it is verified by finite element method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1207-1215
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• 2009

The FTTH is known as an optimal solution to provide broadband services like IPTV and the W-PON is a good alternative to implement the FTTH. It is firstly commercialized in Korea but not widely deployed because of it's high price. In this paper, we suggest a wavelength integration method to drop the price and enhance the utilization of the W-PON. The method makes one logical channel with multiple wavelengths when the W-PON system has to accommodate a signal of which transmission rate is greater than the rate of a single wavelength. Accordingly, the system can accommodate any signal rate. We introduce a frame structure, suggest synchronization and clock recovery methods, and finally show actual applications for the Ethernet and the G-PON.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.289-293
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• 2013

In the noncoherent methods for UWB-IR (ultra-wideband impulse radio), block coded modulation (BCM) is better than the transmitted reference (TR) systems in terms of the energy efficiency and data rate. However, even BCM suffers from the performance degradation in the presence of strong inter-frame interference and inter symbol interference. We propose the transmitted reference based on the BCM (TR-BCM) which is the hybrid system of TR and BCM. Performance evaluation shows that the performance of TR-BCM is better than that of BCM in the high SNR range.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1801-1810
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• 2016

The OpenDaylight controller has been receiving significant attention as one of the enabling open source framework for SDN, and this paper analyzes the architecture and procedure of OpenDaylight based controller cluster. The OpenDaylight controller cluster uses shard based distributed datastore and Raft algorithm to maintain consistency among controllers inside a cluster. The performance evaluation analyzes the leader re-election time as well as latencies of CRUD and Routed RPC according to cluster size, shard role, and sharding strategy, and we discuss the optimal operation strategy for OpenDaylight controller cluster.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.653-663
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• 2002

UMTS/GPRS has its own QoS architecture, but additionally needs to support IP-QoS to provide Internet services. This paper describes an IP-QoS provisioning mechanism in the MPLS-based UMTS/GPRS network. We propose a QoS framework that includes the functional architecture of the MPLS-based GPRS networks and the efficient scheduling mechanism based on Diffserv model. The proposed scheduling mechanims is especially focused on the QoS support for real-time services. It also includes a new buffer management scheme that combines the priority queuing and weighted round robin method. The ns-2 simulator has been used to verify the validity of the proposed scheduling method.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.615-624
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• 2002

The concept of a hyperpresentation, as an extension of a hypermedia, is the presentation in which time-varying multimedia presentations are dynamically linked together and a hyperlink's context can be changed over time at any time during a continuous presentation. While this concept provides users with a flexible and powerful tool for their descriptions of the multimedia presentation, inconsistency problems in the synchronized presentations connected by hyper links can be introduced. This paper introduces a method of describing the hyperpresentation using Petri Net and proposes a methods of detecting inconsistent hyper link loop in the hyperpresentation description.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.372-376
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• 2006

본 논문에서는 홈 내에서 헬스케어 상황정보 서비스를 제공하기 위한 모바일 프락시에 대해 기술한다. 모바일 프락시는 헬스케어 홈 서비스의 목적에 따라 분산자원의 통합 및 맞춤형 관리모델인 분산객체그룹 프레임워크를 기반으로 한다. 모바일 프락시의 주요 기능은 이동성을 지원 및 멀티미디어 스트림 동기화 그리고 그룹통신 지원한다. 특히, 클라이언트의 가용환경에 따라 수행객체에 대한 이동성을 제공한다. 이를 기반으로 헬스케어 상황정보 서비스를 제공하기 위해 사용되는 상황정보는 거주자의 위치, 홈 내에 설치된 센서/기기로부터 수집된 위치, 건강 그리고 쾌적환경 정보를 포함한다. 또한 헬스케어 상황정보 서비스를 위한 응용객체, 자원들의 그룹관리 지원 DOGF를 기반으로 이동성 지원 컴포넌트인 모바일프락시는 거주자 위치이동에 따라 적합한 헬스케어 상황정보 서비스를 제공한다. 모바일프락시를 이용한 헬스케어 상황정보 서비스는 헬스케어 지원 음악치료, 원격상담 서비스와 처방 주의 및 스케줄 알림서비스를 구현했다. 끝으로 제안한 환경에서 거주자의 위치, 시간 및 상황인식에 따라 구현하여 수행한 헬스케어 상황정보 서비스 결과를 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.997-1000
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• 2010

최근 분산자바기술의 발전에 따라 다양한 애플리케이션의 단위기능들은 어디서나 호출 가능한 서비스로 정의되고 있으며, 또한 이러한 서비스들은 새로운 애플리케이션을 구성하기 위한 단위기능으로 사용되고 있다. 특히 RMI, CORBA 등은 가장 널리 활용되고 있는 원격 메서드 또는 서비스 호출 프레임워크로 분산 자바애플리케이션 개발을 위한 중요한 기술이라 할 수 있다. 그러나 이러한 기술들은 모두 원격메서드 또는 서비스의 호출을 위해 클라이언트사이드에서 스텁을 활용하는 기술로, 스텝의 정적생성 및 동기화 필요성으로 인해 다소 사용자 편의성 및 서비스의 접근성이 저해되는 측면이 있다. 따라서 본 논문에서는 이러한 스텁의 생성이 필요 없는 비스텁 방식의 효율적인 원격자바메서드 호출기법을 제시한다. 이 기법을 활용할 경우, 사용자 측면에서 별도의 스텁 없이 원격지의 서비스를 자유롭게 호출할 수 있어 사용자의 편의성 및 서비스 접근성을 크게 향상시킬 수 있으며, 원격 서비스 변경에 따른 동적 서비스 재구성 또한 지원할 수 있어 보다 유연한 애플리케이션 개발이 가능하다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1113-1124
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• 2004

In this paper, we proposed a hardware(H/W) structure which can compress and recontruct the input image in real time operation and implemented it into a FPGA platform using VHDL(VHSIC Hardware Description Language). All the image processing element to process both compression and reconstruction in a FPGA were considered each of them was mapped into H/W with the efficient structure for FPGA. We used the DWT(discrete wavelet transform) which transforms the data from spatial domain to the frequency domain, because use considered the motion JPEG2000 as the application. The implemented H/W is separated to both the data path part and the control part. The data path part consisted of the image processing blocks and the data processing blocks. The image processing blocks consisted of the DWT Kernel fur the filtering by DWT, Quantizer/Huffman Encoder, Inverse Adder/Buffer for adding the low frequency coefficient to the high frequency one in the inverse DWT operation, and Huffman Decoder. Also there existed the interface blocks for communicating with the external application environments and the timing blocks for buffering between the internal blocks The global operations of the designed H/W are the image compression and the reconstruction, and it is operated by the unit of a field synchronized with the A/D converter. The implemented H/W used the 69%(16980) LAB(Logic Array Block) and 9%(28352) ESB(Embedded System Block) in the APEX20KC EP20K600CB652-7 FPGA chip of ALTERA, and stably operated in the 70MHz clock frequency. So we verified the real time operation of 60 fields/sec(30 frames/sec).

• Journal of the Korea Computer Graphics Society
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• v.24 no.3
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• pp.73-81
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• 2018

In this paper, we present a motion-driven rowing simulation framework that allows multiple players to row a boat together by their harmonized movements. In the actual rowing game, it is crucial for the players to synchronize their rowing with respect to time and pose so as to accelerate the boat. Inspired by this interesting feature, we measure the motion similarity among multiple players in real time while they are doing rowing motions and use it to control the velocity of the boat in a virtual environment. We also employ game components such as catching an item which can accelerate or decelerate the boat depending on its type for a moment once it has been obtained by synchronized catching behaviors of the players. By these components, the players can be encouraged to more actively participate in the training for a good teamwork to produce harmonized rowing movements Our methods for the motion recognition for rowing and item catch require the tracking data only for the head and the both hands and are fast enough to facilitate the real-time performance. In order to enhance immersiveness of the virtual environment, we project the rowing simulation result on a wide curved screen.