• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1824-1837
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• 1994

Broadband ISDN will support advanced communication services such as multimedia conference, VOD and electronic news service. Because many of these advanced services require multimedia data delivery, future communication networks must have flexible and efficient multiparty communications capabilities. In this paper we propose a new multicasting method which uses packer filtering capabilities both in a physical network and in a logical network layers. This new scheme has potential to reduce the transmission and packet processing overheads of multicast communications. For the new multicasting method, we develop a group matching algorithm which finds a suitable set of groups that covers multiple target hosts. We show the application of the multicasting method and the group matching algorithm with two simple examoles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3559-3571
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• 2015

This paper addresses the problem of signal acquisition with a sparse representation in a given orthonormal basis using fewer noisy measurements. The authors formulate the problem statement for randomly measuring with strong signal noise. The impact of white Gaussian signals noise on the recovery performance is analyzed to provide a theoretical basis for the reasonable design of the measurement matrix. With the idea that the measurement matrix can be adapted for noise suppression in the adaptive CS system, an adapted selective compressive sensing (ASCS) scheme is proposed whose measurement matrix can be updated according to the noise information fed back by the processing center. In terms of objective recovery quality, failure rate and mean-square error (MSE), a comparison is made with some nonadaptive methods and existing CS measurement approaches. Extensive numerical experiments show that the proposed scheme has better noise suppression performance and improves the support recovery of sparse signal. The proposed scheme should have a great potential and bright prospect of broadband signals such as biological signal measurement and radar signal detection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3028-3039
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• 2015

Recently, the web index of Korea peaked at the top 10 among the eighty six countries, and Korea became the only Asian country ranked at the top level. Korea also has been on the top in the field of Internet penetration rate, in terms of both high-speed broadband and wireless Internet. However, such achievements did not guarantee the national level for the effective use of information utilizing Internet. According to OECD, the national informatization index of Korea has not been free from the middle of the OECD countries. Despite of the heightened pressure in practically enhancing effective information use utilizing Internet, the previous research interests and efforts to develop the Internet-related framework or to identify Internet capabilities rarely existed. The study aims to propose the framework, named "Internet Information Orientation" that illustrates the relationship between Internet capabilities and national competitiveness on Internet. The research identified the specific Internet capabilities, reclassified the capabilities based on the research issues provided at the 6^th international conference on Internet held in December 2014, and finally described the rigorous research endeavors on the issues. As a result, 16 papers presented and selected as the outstanding papers at the conference handle issues to be brought together, which include: Wireless Network, Internet of Things, Green Computing, Multimedia Processing, Big Data and Text Mining, Database in Cloud Environment, Business Intelligence, Software Engineering, IT Strategy & Policy, and Social Network Services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.873-892
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• 1998

In this paper, we propose an architecture of multimedia communication terminal that can e used in broadband ISDN environments. To design and implement the multimedia communication terminal, we analyzed the structure of multimedia terminals and the types of services which is recommended by public and private standard or ganization, such as ITU-T, Digital Audio-Visual Council(davic) and ATM Forum. The multifunctional communication terminal designed in this paper could allow inter-working between existing communication terminals on the heterogeneousnetwork and accept current and advanced multimedia communication application flexible. An implemented terminal is consisted of the multimedia processing board and the ATm interface board that is installed in PCI bus on personal computer. The integrated service multimedia communication terminal that is implemented supports retrieval, distributive and conversational communication service simultaneously. And then we performaned functional module test according to the individual communication services.

• Journal of electromagnetic engineering and science
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• v.11 no.4
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• pp.304-310
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• 2011

The application of time-domain methods in emission measurement instruments allows for a reduction in scan time by several orders of magnitude and for new evaluation methods to be realized such as the real-time spectrogram to characterize transient emissions. In this paper two novel systems for time-domain EMI measurements above 1 GHz are presented. The first system combines ultra-fast analog-to-digital-conversion and real-time digital signal processing on a field-programmable-gate-array (FPGA) with ultra-broadband multi-stage down-conversion to enable measurements in the range from 10 Hz to 26 GHz with high sensitivity and full-compliance with the requirements of CISPR 16-1-1. The required IF bandwidths were added to allow for measurements according to MIL-461F and DO-160F. The second system realizes a system of time-interleaved analog-to-digital converters (ADCs) and has an upper bandwidth limit of 4 GHz. With the implementation of an automatic mismatch calibration, the system fulfills CISPR 16-1-1 dynamic range requirements. Measurements of the radiated emissions of electronic consumer devices and household appliances like the non-stationary emissions of a microwave oven are presented. A measurement of a personal computer's conducted emissions on a power supply line according to DO-160F is given.

• ETRI Journal
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• v.26 no.5
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• pp.375-383
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• 2004

This paper proposes a common interleaving method associated with independent channel-encoding among transmitter antenna branches in orthogonal frequency and code division multiplexing based on multiple-input multiple-output (MIMO) multiplexing to achieve an extremely high throughput such as 1 Gbps using a 100 MHz bandwidth. This paper also investigates the average packet error rate performance as a function of the average received signal energy per bit-to-background noise power spectrum density ratio $(E_b/N_0)$. We found that the loss in the required average received $E_b/N_0$ of the proposed method is only within approximately 0.3 dB in up to a 12-path Rayleigh fading channel, using 16QAM and Turbo coding with a coding rate of 5/6. We also clarify that even for a large fading correlation among antenna branches, 1 Gbps is still possible by increasing the transmission power. Therefore, the proposed method reduces the processing rate to 1/4 in the turbo decoder with only a slight loss in the required average received $E_b/N_0$.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.453-462
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• 2007

NGN is a packet-based converged network to support session and non-session based services in QoS-enabled broadband transport technologies. Resource and admission control functions(RACF) of NGN have been considering COPS and SNMP as resource management protocols to collect network topology and resource status information of transport network. This paper defines requirements of resource management in NGN transport network, and proposes protocol independent information model to keep consistency of data models of each resource management protocol. Based on this information model described with UML class diagram, we designed and implemented NGN resource management system on Web Services.

• The KIPS Transactions:PartC
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• v.16C no.3
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• pp.383-392
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• 2009

Next generation network (NGN) is a packet-based converged network to support session and non-session services in QoS-enabled broadband transport network. QoS based resource control must be defined to support differentiated services for various network users in NGN. This paper defined parallel control schemes for NGN resource control interfaces to minimize session and resource control delays. We simulated the existing and proposed NGN control schemes to measure and analyze control delays and completion ratios. By arrival rate of 120 in two-phase resource control, we checked out that completion ratios of sequential and parallel schemes achieved 100%, and the control delay of parallel scheme was improved by about 21.5% compared to that of sequential scheme.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.217-222
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• 2005

The IEEE 802.11 based wireless local area networks are candidates to lead the broadband connectivity in the home and office scenarios. Recently IEEE proposed the 802.11e as a new standard to provide appropriate Quality of Services to a plethora of emerging real-time multimedia and high demanding applications such as high definition movie and audio distribution, video-conference and voice over IP. This paper studies the IEEE 802.11e/IEEE 802.11b interactions focusing on potential unfairness problems that might appear in networks with heterogeneous wireless LAN technologies as well as in the IEEE 802.11e deployment phase.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.76-82
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• 2015

A hybrid fiber-optic sensor system which combines fiber Bragg grating sensors and a Michelson interferometer has been constructed and evaluated for condition monitoring of large scale wind turbines. In order to measure multiple stresses applied to wind turbines such as strain, temperature and vibration, the system uses single broadband light source. It addresses both types of sensors, which simplifies the optical setup and enhances the cost-effectiveness of condition monitoring system. An athermal-packaged FBG is used to supply quasi-coherent light, of which coherence length is about 3.28mm, for the Michelson interferometer demodulation. Experimental results demonstrated that the proposed fiber-optic sensor system was capable of measuring strain and temperature with measurement accuracy of 1pm. Also 500~2000Hz vibration signals were successfully analyzed by applying FFT signal processing to interference signals.