• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.914-923
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• 2015

Recently, as the number of smart devices (such as smart TV or Web based IPTV) increases, the way of digital broadcast contents is changed. This change leads that conventional broadcast media accepts Web platform and its services to provide more quality contents. Based on this change, in education field, education broadcasting also follows the trend. The traditional education broadcasting platforms, which just delivered the lecture in one-way, are utilized the Web technology to make interaction between teacher and student. Current education platforms, however, are insufficient to satisfy users' demands for two-way interactions. This paper proposes a new remote collaborative learning platform which able to provide high interactivity among users. Based on new functional requirements from original use case, the platform provides collaborative contents sharing and collaborative video streaming techniques by utilizing WebRTC (Web Real-Time Communication) technology. The implementation demonstrates the operability of proposed system.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.29-39
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• 2010

This paper presents and analyzes laboratory test results of distributed translator (DTxR) for distributed frequency network (DFN) in the ATSC (Advanced Television Systems Committee) terrestrial digital TV broadcasting system. The DTxR laboratory test is classified to receiving part test and transmitting part test. The receiving part test includes dynamic range, random noise, single echo, and adjacent channel interference. The transmitting part test includes quality of output signal (out-of channel emission, quality of transmitting signal, and phase noise), frequency synchronization among output signals, and TxID (Transmitter Identification) signal's affect to the legacy receiver. By the laboratory test results, the receiving part of DTxR eliminates average -2.5 dB of single echo and has average 17.5 dB at TOV (Threshold of Visibility) under random noise environment. In addition, the transmitting part of DTxR satisfies the specification of US FCC (Federal Communications Commission), and frequency difference among DTxR output signals is less than 0.001 Hz.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.596-610
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• 2007

In order to reduce the complexity of SVC encoding, we introduce a fast mode decision method in the enhancement layers of spatial scalability by selectively performing the inter-layer residual prediction of SVC. The Inter-layer residual prediction coding in Scalable Video Coding has a large advantage of enhancing the coding efficiency since it utilizes the correlation between two residuals from a lower spatial layer and its next higher spatial layer. However, this entails the dramatical increase in the complexity of SVC encoders. The proposed method is to analyze the characteristics of integer transform coefficients for the subtracted signal for two residuals from lower and upper spatial layers. Then it selectively performs the inter-layer residual prediction coding and rate-distortion optimizations in the upper spatial enhancement layer if the SAD values of residuals exceed adaptive threshold values. Therefore, by classifying the residuals according to the properties of integer-transform coefficients only with SAD of residuals between two layers, the SVC encoder can perform the inter-layer residual coding selectively, thus significantly reducing the total required encoding time. The proposed method results in reduction of the total encoding time with 51.5% in average while maintaining the RD performance with negligible amounts of quality degradation.

• Journal of Broadcast Engineering
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• v.27 no.6
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• pp.936-939
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• 2022

As air combat system technologies developed in recent years, the development of air defense systems is required. In the operating concept of the anti-aircraft defense system, selecting an appropriate armament for the target is one of the system's capabilities in efficiently responding to threats using limited anti-aircraft power. Much of the flying threat identification relies on the operator's visual identification. However, there are many limitations in visually discriminating a flying object maneuvering high speed from a distance. In addition, as the demand for unmanned and intelligent weapon systems on the modern battlefield increases, it is essential to develop a technology that automatically identifies and classifies the aircraft instead of the operator's visual identification. Although some examples of weapon system identification with deep learning-based models by collecting video data for tanks and warships have been presented, aerial vehicle identification is still lacking. Therefore, in this paper, we present a model for classifying fighters, helicopters, and drones using a convolutional neural network model and analyze the performance of the presented model.

• Korean Security Journal
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• no.24
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• pp.125-146
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• 2010

The G20 summit is the premier forum for international economic cooperation and it will be held in Seoul in November 2010. However, protests are expected during the Seoul summit, as a part of the deepening global war against capitalism. The Korean Police need to deal with these protests effectively in order to provide security to the participating leaders and make the meeting run on wheel as planned. The current study attempts to analyze the death of Ian Tomlinson who died in the context of a heavily policed protest during 2009 G20 London summit. There are number of unique features regarding this incident, such as the public scrutiny of police conduct through video footage, the police use of excessive force, and the process to hold the police to account for misconduct. This incident caused serious damages to the public's faith in the British police. Based on the analysis, this study found that during the G20 London summit British police had the problems such as the lack of the clear standards on the use of force, improper training in the use of force, poor communications with the media and protesters, inappropriate use of the close containment tactic, and the failure to display police identification. Therefore, this study suggests the inducement of peaceful protests, the adoption of a set of standards on the use of force, public order training that is more directed and more relevant to the public order challenges facing the Korean police, improvement of the communication with the media and protesters, enhancement of individual officer's accountability as public order policing strategies for G20 Seoul summit meeting. However, the most fundamental principle is that Korean police must place a high value on tolerance and winning the consent of the public.

• Archives of design research
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• v.15 no.4
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• pp.1-14
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• 2002

In the past, companies concentrated their efforts on developing new technologies and producing new products. But new technologies in this information age do not make difference any more comparing to other companies. In this marketing environment, a company must appeal strongly their own image to the customers' brains to make better difference than other companies do. One of the best way to make their own image in the customer's brains might be outgrowing themselves of the one-way communication such as the printed-media or broadcast-media and preparing some space such as advertisement halls or pavilions where customers and companies meet each other and make mutual communications between both of them. Therefore, we need to study systematically on the design elements in the advertisement halls or pavilions. To begin with, we should lully understand the basic idea by looking up the reference literature. We case-studied on the basic of constructive elements of advertise halls of both SAMSUNG and LG Electronics Co. The purpose of this study is to realize that we can transfer effectively the company's image to the customers only if we fully understand company's business philosophy and vision in advance to start design the advertisement hails. We should also realize that it is also important to manage systematically the company's design strategic elements' to achieve its changing goals in more logical and scientifically way.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.51-56
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• 2014

High-availability seamless redundancy (HSR) is a protocol for fault-tolerant Ethernet (FTE) networks. It provides two frame copies and each copy is forwarded on a separate physical path, which provides zero fail-over time. Therefore, the HSR is becoming a potential candidate for various real-time FTE applications. However, the generation and circulation of unnecessary frames due to the duplication of every sending frame is inherent drawback of HSR. Such drawback degrades the performance of the network and may deplete its resources. In this paper, we present a new algorithm called port locking (PL) based on the media access control (MAC) address to solve the abovementioned problem in popular connected-rings network. Our approach makes the network gradually learn the locations of the source and the destination nodes without relying on network control frames. It then prunes all the rings that do not contain the destination node by locking corresponding rings' entrance ports. With the PL algorithm, the traffic can be significantly reduced and therefore the network performance will be greatly enhanced specially in a large scale connected-rings network. Analytical results are provided to validate the PL algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.886-895
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• 2005

As the networked media technology have been grown in recent, there have been many research works to deliver high-quality video such as HDV and HDTV over the Internet. To realize high-quality media service over the Internet, however, the network adaptive streaming scheme is required to adopt to the dynamic fluctuation of underlying networks. In this paper, we design and implement the network-adaptive HD(high definition) MPEG-2 streaming system employing the frame-based prioritized packetization. Delivered video is inputted from the JVC HDV camera to the streaming sewer in real-time. It has a bit-rate of 19.2 Mbps and is multiplexed to the MPEG-2 TS (MPEG-2 MP@HL). For the monitoring of network status, the packet loss rate and the average jitter are measured by using parsing of RTP packet header in the streaming client and they are sent to the streaming server periodically The network adaptation manager in the streaming server estimates the current network status from feedback packets and adaptively adjusts the sending rate by frame dropping. For this, we propose the real-time parsing and the frame-based prioritized packetization of the TS packet. The proposed system is implemented in software and evaluated over the LAN testbed. The experimental results show that the proposed system can enhance the end-to-end QoS of HD video streaming over the best-effort network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.12
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• pp.944-953
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• 2013

Recently, a storage media is becoming smaller and storage capacity is also becoming larger than before. However, important data was leaked through a small storage media. To solve these serious problem, many security companies manufacture secure USBs with secure function, such as data encryption, user authentication, not copying data, and management system for secure USB, etc. But various attacks, such as extracting flash memory from USBs, password hacking or memory dump, and bypassing fingerprint authentication, have appeared. Therefore, security techniques related to secure USBs have to concern many threats for them. The basic components for a secure USB are secure authentication and data encryption techniques. Though existing secure USBs applied password based user authentication, it is necessary to develop more secure authentication because many threats have appeared. And encryption chipsets are used for data encryption however we also concern key managements. Therefore, this paper suggests mutual device authentication based on PUF (Physical Unclonable Function) between USBs and the authentication server and key management without storing the secret key. Moreover, secure USB is systematically managed with metadata and authentication information stored in authentication server.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.471-492
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• 2017

The demand and interest in big data analytics are increasing rapidly. The concepts around big data include not only existing structured data, but also various kinds of unstructured data such as text, images, videos, and logs. Among the various types of unstructured data, text data have gained particular attention because it is the most representative method to describe and deliver information. Text analysis is generally performed in the following order: document collection, parsing and filtering, structuring, frequency analysis, and similarity analysis. The results of the analysis can be displayed through word cloud, word network, topic modeling, document classification, and semantic analysis. Notably, there is an increasing demand to identify trending topics from the rapidly increasing text data generated through various social media. Thus, research on and applications of topic modeling have been actively carried out in various fields since topic modeling is able to extract the core topics from a huge amount of unstructured text documents and provide the document groups for each different topic. In this paper, we review the major techniques and research trends of text analysis. Further, we also introduce some cases of applications that solve the problems in various fields by using topic modeling.