• Journal of Broadcast Engineering
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• v.27 no.3
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• pp.318-331
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• 2022

With the recent development of hardware computing devices and software based frameworks, machine tasks using deep learning networks are expected to be utilized in various industrial fields and personal IoT devices. However, in order to overcome the limitations of high cost device for utilizing the deep learning network and that the user may not receive the results requested when only the machine task results are transmitted from the server, Collaborative Intelligence (CI) proposed the transmission of feature maps as a solution. In this paper, an efficient compression method for feature maps with vast data sizes to support the CI paradigm was analyzed and presented through experiments. This method increases redundancy by applying feature map reordering to improve compression efficiency in traditional video codecs, and proposes a feature map method that improves compression efficiency and maintains the performance of machine tasks by simultaneously utilizing image compression format and video compression format. As a result of the experiment, the proposed method shows 14.29% gain in BD-rate of BPP and mAP compared to the feature compression anchor of MPEG-VCM.

• Journal of Broadcast Engineering
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• v.27 no.4
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• pp.548-560
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• 2022

Video based Point Cloud Compression (V-PCC) is one of the compression methods for compressing point clouds, and shows high efficiency in dynamic point cloud compression with movement due to the feature of compressing point cloud data using an existing video codec. Accordingly, V-PCC is drawing attention as a core technology for immersive content services such as AR/VR. In order to effectively service these V-PCC contents through a media streaming platform, it is necessary to encapsulate them in the existing media file format, ISO based Media File Format (ISOBMFF). However, in order to service through an adaptive streaming platform such as Dynamic Adaptive Streaming over HTTP (DASH), it is necessary to encode V-PCC contents of various qualities and store them in the server. Due to the size of the 2D media, it causes a great burden on the encoder and the server compared to the existing 2D media. As a method to solve such a problem, it may be considered to configure a streaming platform based on content obtained through V-PCC content encoding based on SHVC. Therefore, this paper encapsulates the SHVC-based V-PCC bitstream into ISOBMFF suitable for DASH service and proposes a configuration method to service it. In addition, in this paper, we propose ISOBMFF encapsulation and DASH configuration method to effectively service SHVC-based V-PCC contents, and confirm them through verification experiments.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.310-339
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• 2015

In this paper, the possibility of a terrestrial fixed 4K UHD (Ultra High Definition) and mobile HD (High Definition) convergence broadcasting service through a single channel employing the FEF (Future Extension Frame) multiplexing technique in DVB (Digital Video Broadcasting)-T2 (Second Generation Terrestrial) systems is examined. The performance of such a service is also investigated. FEF multiplexing technology can be used to adjust the FFT (fast Fourier transform) and CP (cyclic prefix) size for each layer, whereas M-PLP (Multiple-Physical Layer Pipe) multiplexing technology in DVB-T2 systems cannot. The convergence broadcasting service scenario, which can provide fixed 4K UHD and mobile HD broadcasting through a single terrestrial channel, is described, and transmission requirements of the SHVC (Scalable High Efficiency Video Coding) technique are predicted. A convergence broadcasting transmission system structure is described by employing FEF and transmission technologies in DVB-T2 systems. Optimized transmission parameters are drawn to transmit 4K UHD and HD convergence broadcasting by employing a convergence broadcasting transmission structure, and the reception performance of the optimized transmission parameters under AWGN (additive white Gaussian noise), static Brazil-D, and time-varying TU (Typical Urban)-6 channels is examined using computer simulations to find the TOV (threshold of visibility). From the results, for the 6 and 8 MHz bandwidths, reliable reception of both fixed 4K UHD and mobile HD layer data can be achieved under a static fixed and very fast fading multipath channel.

• Journal of Computing Science and Engineering
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• v.7 no.3
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• pp.187-197
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• 2013

Security has long been a challenging problem in wireless networks, mainly due to its broadcast nature of communication. This opens up simple yet effective measures to thwart useful communications between legitimate radios. Spread spectrum technologies, such as direct sequence spread spectrum (DSSS), have been developed as effective countermeasures against, for example, jamming attacks. This paper surveys previous research on securing a DSSS channel even further, using physical layer attributes-keyless DSSS mechanisms, and watermarked DSSS (WDSSS) schemes. The former has been motivated by the fact that it is still an open question to establish and share the secret spread sequence between the transmitter and the receiver without being noticed by adversaries. The basic idea of the latter is to exploit the redundancy inherent in DSSS's spreading process to embed watermark information. It can be considered a counter measure (authentication) for an intelligent attacker who obtains the spread sequence to generate fake messages. This paper also presents and evaluates an adaptive DSSS scheme that takes both jam resistance and communication efficiency into account.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.154-158
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• 2008

Autonomous business card exchange system using ZigBee with low power and short range was configured In the autonomous business card exchange system characterized as full mesh network in which every node exchanges each information one by one, it is necessary to reduce the time taken for information to be exchanged. In this paper, the novel method where the node ID is exchanged based on CSMA/CA and then the information of each node is broadcast to other nodes according to the ID list based on FIFO. The time required for exchanging information using the proposed method was analyzed and compared with the direct exchange method based on CSMA/CA. The results show that it takes less time in the proposed method than the direct exchange time.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.201-209
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• 2017

This paper is a smartphone object recognition system using hierarchical convolutional neural network. The overall configuration is a method of communicating object information to the smartphone by matching the collected data by connecting the smartphone and the server and recognizing the object to the convergence neural network in the server. It is also compared to a hierarchical convolutional neural network and a fractional convolutional neural network. Hierarchical convolutional neural networks have 88% accuracy, fractional convolutional neural networks have 73% accuracy and 15%p performance improvement. Based on this, it shows possibility of expansion of T-Commerce market connected with smartphone and broadcasting media.

• Journal of the Korea Society of Computer and Information
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• v.18 no.5
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• pp.25-34
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• 2013

One of the most typical examples of convergence is IPTV, a convergence of broadcast and telecommunication. Demand for IPTV has been increased so rapidly that a new TV set, called a smart TV, has appeared. One of the most important factors for IPTV business success is content. If an IPTV station provides popular content and subscribers can conveniently watch it then the station has a good chance of success. Therefore, the content management module is extremely important component of IPTV systems. In the current IPTV systems, operators must be present at the office to access a Content Management System(CMS). We implement a web CMS so that the operators can access the CMS anytime and anywhere as long as they are connected to Internet.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.709-717
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• 2002

A new multi constant modulus algorithm (MCMA) for a blind decision feedback equalizer is proposed. In order to avoid the error propagation problem in the conventional DFE structure, Feed-Back Filter coefficients are updated only after Feed-Forward Filter coefficients are sufficiently converged to the steady state. Therefore, it has the problem of slow convergence speed characteristics. To overcome this drawback, the proposed MCMA algorithm uses not only new cost function considering the minimum distance between the received signal and the representative value containing the statistical characteristics of the transmitted signal, but also adaptive step-size according to the equalizer outputs to fast convergence speed of FBF. Simulations were carried out under the certified communication channel environment to evaluate a performance of the proposed equalizer. The simulation results show that the proposed equalizer has an improved convergence and SER performance compared with previous methods. The proposed techniques offer the possibility of practical equalization for cable modem and terrestrial HDTV broadcast (using 8-VSB or 64-QAM) applications.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.43-52
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• 2019

360 Virtual Reality(VR) service is getting attention in the domestic streaming market as 5G era is upcoming. However, existing IPTV-based 360 VR video services use upto 4K 360 VR video which is not enough to satisfy customers. It is generally required that over 8K resolution is necessary to meet users' satisfaction level. The bit rate of 8K resolution video exceeds the bandwidth of single QAM channel(38.817mbps), which means that it is impossible to provide 8K resolution video via the IPTV broadcast network environment. Therefore, we suggest and implement the edge streaming system for low-latency streaming to the display devices in the local network. We conducted experiments and confirmed that 360 VR streaming with a viewport switching delay less than 500ms can be achieved while using less than 100mbps of the network bandwidth.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.69-74
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• 2018

IP and SIP public broadcasting systems developed in Korea and abroad are developed in a Windows or Linux server environments and are installed in a server-rack structure, have high power consumption, and are difficult to remotely respond to system failures. In this paper, IoT platform is designed to connect IoT device and gateway to IoT service server by using internet service structure. We also designed a server based on embedded OS that can provide a variety of public safety management services according to the order of the server with built-in call processing and broadcasting function that can handle emergency calls and emergency broadcasts in public places using this structure. This server is interoperable with a variety of SIP-based call and broadcast devices that support the standard SIP and can be integrated with an in-house phone and on-premises system.