TaeYeon Kim

A WDM-Ethernet hybrid passive optical network architecture

The wavelength division multiplexing-passive optical network (WDM-PON) has been known as the utmost advanced technology with high security, guaranteed QoS, transparent protocol and so on. However, WDM-PON is too expensive for general users, and its bandwidth is too much for the present services of individual general subscribers. This paper introduces a hybrid PON based on WDM, namely WDM-Ethernet PON (WE-PON), in which WDM-PON is integrated with time division multiplexing PON (TDM-PON) by AWG and splitter. WE-PON with 32 branch splitter can get down very close to that of TDM-PON. It can significantly lower the out side plant cost as well as maximizing the fibre utilization

On-line Magnetic Distortion Calibration Method for a Magnetometer

This paper describes an on-line magnetic distortion calibration procedure for a magnetometer. The horizontal magnetic field is calculated through the earth magnetic field sensed by 3-axes magnetometer. The ellipse equation is derived from a set of horizontal magnetic field data using least square method and calibration parameters are determined. The calibration process is performed iteratively until parameters are not renewed, and experimental results show the effectiveness of the devised method.

Coordination of wavelength and time-window assignment in WDM-based TDM hybrid-PONs

In passive optical networks (PONs), the low effectiveness in terms of service utilization and network evolution have been important design issues. In this article, we introduce a hybrid access network architecture, so called scalable WDM-based Ethernet hybrid-PON (SWE-PON), which features a wavelength-division-multiplexed (WDM) feeder network using a combination of tunable laser device (TLD) and cyclic arrayed waveguide grating (AWG) and time-division-multiplexed (TDM) distribution network based on a reflective transmission mode. Necessary conditions needed to guarantee flawless packet transmission through normal WDM/TDM hierarchical PONs including the SWE-PON, are analyzed. We also propose a hierarchical fair time-window allocation mechanism which coordinates wavelength assignment and time-window bandwidth allocation so that high link utilization and fair bandwidth allocation are guaranteed in every multiplexing level.

5G CHAMPION - Rolling out 5G in 2018

The 5G CHAMPION Consortium will provide the first fully integrated and operational 5G prototype in 2018 - this effort is a major leap ahead compared to existing punctual technology trials, such as, e.g., Proof-of-Concept platforms focusing on mmWave communication in specific bands, etc. This paper describes the overall set-up including a synergetic combination of technologies such as beamforming based mmWave & Satellite service provisioning, virtualized infrastructure, software reconfiguration across the entire stack, accurate positioning and high-speed solutions. The key enablers are described in detail and related efforts in standards and regulation organizations are discussed.

A healthcare information sharing scheme in distributed cloud networks

Current information & communication technology infrastructures are struggling for a wide variety of devices, services, and business and technology evolution. Cloud computing is becoming a promising platform and has developed rapidly. In contrast to traditional enterprise IT solution, it enables enterprises to procure computing resources on demand basis and delegate management of all the resources to the cloud service provider. Healthcare information networks have emerged as one of the major research area in the cloud networks. Healthcare information is communication and information systems and technology that facilitate quality patient care, progressive medical education, and innovative research. Healthcare information networks must ensure the reliability and efficiency because it transfers highly personal data. Thus, it guarantees and keeps a certain level of transfer efficiency. In the distributed cloud environments, management costs for the network and computing resources are solved fundamentally through the integrated management system. It can increase the cost savings to solve the traffic explosion problem of core network via a distributed micro datacenters (DCs). However, traditional flooding methods may cause a lot of traffic because it had to send data to all the neighbor DCs. Restricted Path Flooding algorithms have been proposed for this purpose. In large networks, there is still the disadvantage that may occur traffic. In this paper, we develope lightweight path flooding algorithm to improve existing flooding algorithm using hop count restriction. This paper also investigates the problem of partial information sharing.

Scalable CDN service PoC over distributed cloud management platform.

With the advent of disruptive programmable network technologies such as SDN and NFV, network evolution has been spurred by accommodating cloud service infrastructure inside the network. Accordingly the key issues for the service orchestration and harmonization to provide scalable and reliable application services on that environment would be investigated through the PoC service scenarios.

Advanced multicast service scheduling mechanism with IGMP snooping in WDM-PON

In this paper, we deal with the multicast service management to efficiently support the broadcasting TV and the near real time high quality VoD (video on demand) service though the data communication networks. This is an emerging issue of the next generation network. Until now, several network architectures have been proposed but most of these have been concentrated on increase of the basic network bandwidth or induced the higher system complexity. The hybrid WDM-PON guarantees both kinds of traffic the independent and stable service by introducing the shared broadcast wavelength for multicast group traffic service. The proposed dynamic multicast group scheduling (DMGS) based on hybrid WDM-PON efficiently supports the common Internet traffic as well as the large number of multicast groups by maximizing the service share-index of registered multicast groups which uses the broadcast wavelength in real time

Performance enhancement of differentiated services in E PON: smaller buffer and efficient traffic service isolation

The performances of differentiated services in E-PON can be enhanced by the QoS based bandwidth reservation. With dynamic service tracking, the data buffer size and the light-load penalty are reduced with the reliable traffic isolation

Sensorless Drive of the BLDC Motor using a Line Voltage Difference

In recent years, sensorless drive schemes have been proposed widely and most of them are based on the ZCP (Zero Crossing Point) detection of the BEMF (Back Electro-Motive Force). These schemes have two main problems. One is that ZCP may not be detected at low speed and thus a forced drive is required. The other problem is that there is 30° phase difference between ZCP and the motor commutation instant and to ensure proper operation, this gap should be accounted for. To solve these problems a circuit is devised for detecting ZCP of the BEMF difference through the line voltage difference. Experimental results show that the output of this circuit is identical to that of the Hall sensor signal, and velocity control of a BLDC motor is possible without the sensor.

Share Based-Channel Scheduling Algorithm for Multicast Video Delivery in WDM Optical Access Networks

One of the important issues of future convergence service design in access networks is the ability to support different kinds of video delivery services for high quality IP-TV and multicast Video on Demand (VoD). In this paper, we address how to efficiently allocate video transmission channels based on multicast management technology in shared wavelength division multiplexed-passive optical network (WDM-PON). The shared WDM-PON introduces a broadcast downstream wavelength to support multicast videos in the point-to-point WDM-PON. Based on the shared architecture and multicast management technologies, the proposed dynamic channel scheduling arbitrates transmission channels of videos. It uses the information of broadcast video share to maximize traffic share in the optical layer. By maintaining high video share, proposed algorithm supports the maximum number of high quality multicast videos without serious service interference to real-time videos, delay-able videos, and internet services. In addition, it also reduces the packet processing burden and buffer size of the optical line termination (OLT). The analytic and simulation results validate the effectiveness of the proposed algorithm.