Woongshik You

Video retrieval based on the object's motion trajectory

This paper presents an efficient way of indexing and searching based on object-specific feature for video retrieval at different semantic levels. By tracking individual objects with segmented data, we generate motion trajectories with moving trails of objects and set a model using polynomial curve fitting. The trajectory model is used as an indexing key for accessing each object in the semantic level. The proposed searching system supports various types of queries including query-by-example, query- by-sketch and query on weighting parameters for event-based retrieval. When retrieving the interested video clips, the system returns the best-matched events in the similarity order. In addition, we implement a temporal event graph for direct accessing and browsing a specific event in the video sequence.

Design and Implementation of a Headend Cable Modem and a User Terminal supporting Multiple Downstream Channel Bonding

In this paper, we present efficient designs and implementations of a headend cable modem and a user terminal supporting downstream channel bonding for the HFC plant. The developed systems can enable various communication- broadcasting converged services over HFC network, such as HD IP-TV. The downstream channel bonding combines multiple downstream channels to provide greater aggregate bandwidth up to 400 Mbps for a user. We also present the test and demonstration results showing the advantages of the developed systems supporting the downstream channel bonding scheme. The proposed designs and implementations in this paper can be used to develop advanced headend cable modem and user terminal which provide hundreds Mbps transmission speed through downstream channel bonding, and enable new converged services over HFC network.

Design and implementation of DCAS user terminal

This paper presents an efficient design and implementation of user terminal for Downloadable Conditional Access System (DCAS). The DCAS system enables cable operators to flexibly change and update their Conditional Access Systems (CAS) without hardware changes by downloading CA applications through Hybrid Fiber Coaxial (HFC) network. In order to do this, the DCAS user terminal provides DCAS functionalities including CA client download and update through DCAS protocol. The proposed design and implementation in this paper can be used to develop advanced DCAS user devices such as smart phone supporting broadcasting and communication converged services.

Content-based video retrieval by indexing object's motion trajectory

We propose a video retrieval scheme indexing the objects motion trajectory information. The motion trajectories of moving objects are partitioned by fixed time intervals. Each segmented motion trajectory is described using the coefficients of 2/sup nd/ order polynomials that represent the centroids of the moving objects in time evolution. The set of polynomial coefficients is used as a motion trajectory descriptor. The proposed scheme provides small-sized indexing and low matching complexity.

Study on the multi-modal data preprocessing for knowledge-converged super brain

Due to the ever-growing amount of data produced through versatile hyper-connected networks, in pursuit of the Internet of Everything (IoE), the challenges to derive useful knowledge from these big IoE data have received increasing attention. This research deals with fusing multi-modal data from the IoE networks, in order to efficiently provide a set of highly relevant input data for further high-level data analytics such as machine learning. We propose a functional structure of such a data fusion and implement a system prototype based on Apache Spark. Further, our concept is validated through the experiments using the KDD Cup 1999 data.

UHDTV transmission based on broadcasting channel bonding

This paper presents a UHDTV transmission scheme using broadcasting channel bonding which transmits a UHDTV program through multiple broadcasting channels. A signaling method is also introduced for providing service information about the UHDTV program transmitted over multiple broadcasting channels.

Research on the functional design of the next generation terrestrial mobile HD television

We propose the functional design of the next generation mobile HD television. The next generation mobile television should have functions which can support successful business models to overcome the failing problems of the conventional services. For this, the next generation mobile television should have to support the HDTV over 40 inches screen for public transportations such as buses and trains etc and have non-linear programming functions to deliver the contents users want through mobile broadcasting network.

Experimental service of 3DTV cable broadcasting using dual HD streams

An experimental service of 3DTV cable broadcasting was made by delivering stereoscopic 3D video to the users in dual HD stream format. Also, an experimental attempt was made to provide backward compatibility for conventional 2D Set-top Boxes (STB) receiving and displaying only one stream of stereoscopic 3D video signal called reference video. For the experimental service, stereoscopic 3D video signals are encoded with 35 Mbps and transmitted over single broadcasting channel by using the existing cable headend and transmission systems. Prototypes of the software-based 3D encoder and 3D STB were also used for the experimental service. Through the experimental broadcasting service, it was possible to provide HD 3DTV broadcasting service under legacy cable environment and to support backward compatibility for the conventional 2D STBs to receive HD broadcasting by using the reference video. A survey revealed that about 60% of the viewers answered the image quality of stereoscopic 3D video in dual HD stream format was better than that in single HD stream format.

Performance analysis and implementation of a DVB-C2 transceiver

This paper depicts a results of field test for an implemented digital video broadcasting for cable system (DVB-C2) transceiver, which has been implemented using field programmable gate arrays (FPGAs). The test results show the physical channel status and performance of the DVB-C2 transceiver, which includes the sampling clock offset (SCO), the frequency offset (FO), the frequency response of the hybrid fiber coax (HFC) channel, the uncoded-bit error rate (BER) before the forward error correction (FEC) decoder, and the BER after the FEC decoder. Since the moving picture exports group-transport stream (MPEG-TS) is received successfully with a raw data rate of 55 Mbps through a commercial in-service HFC network, a high data rate such as ultra-high definition (UHD) can be expected to be serviced. In addition, because the measured uncoded-BER satisfies the requirement of 10-2 uncoded-BER, the implemented DVB-C2 transceiver can support 4096QAM as well as 16384QAM. Therefore, it can be used as a cable modem supporting DVB-C2 and the data-over-cable-service-interface-specifications (DOCSIS) 3.1.

A study on reducing spectrum edge of OFDM signal

To reduce an adjacent channel interference (ACI) by sharpening the spectrum edges of the orthogonal frequency division multiplexing (OFDM) signal in the frequency domain, an windowing function is applied to the individual OFDM symbols in time domain. A commonly used windowing function is the raised cosine function with a roll-off factor. In this paper, the spectrum of an OFDM signal and -45 dB bandwidth have been investigated with respect to various roll-off factors used in the data-over-cable-service-interface-specifications (DOCSIS) 3.1 using OFDM.