• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.62-66
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• 2015

This paper introduces various applications and contents of digital signage, and analyzes conventional communication techniques to increase communication range. To realize digital signage in long distance, this paper proposes a hybrid modulation scheme and analyzes its performance. To verify its performance in real channel environment, we mapped symbols and experimented data transmission and reception with a visible light communication module with USRP. As a result, we confirmed a data receiving range and power of transmission and reception of the hybrid modulation mode. Also, we showed that the proposed modulation scheme has better performance of communication range and power efficiency than that of the conventional QAM technique.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.545-548
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• 2017

This study describes the design and implementation of IFA(Input Filter Assembly) for Digital Satellite Communication. The IFA unit for SHF band consists of coupler, LPF(Low Pass Filter) and input Filter. Through the pre-simulation analysis of space environment, the possibility of the malfunction of equipment minimized and we designed a reliable IFA through simulation for vibration analysis generated during the launch, and compared pre-simulation of main performance results to test results about main performances of IFA after production.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.333-339
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• 2012

Global flow of communication is a trend of high speed, digitalization, and high-capacity. Furthermore, spread spectrum method has been dominantly utilized to efficiently use the frequency which is the scarce resource. The PLL (Phase Lock Loop) which is a widely used frequency synthesizer in communication systems has few problems such as status interferences and hence, this study utilized the DDS (Direct Digital Synthesis) which is a digital device that can minimize the problems of PLL for the study on the performance evaluation of high speed frequency hopping system design. We designed a system that practices high speed frequency hopping and interprets improvement of error-rates and evaluated its performance.

• International Journal of Contents
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• v.11 no.3
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• pp.24-33
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• 2015

Against the backdrop of Habermas' theory of communicative action, we empirically analyzed the level of interactivity and narratives offered in nation-states' ministry of foreign affairs Web sites. A multiple regression analysis was performed in an attempt to identify factors affecting the level of interactivity in such Web sites. Findings revealed that the level of economic development is the sole significant factor in regards to the level of interactivity. Further, self-interested, goal-directed, and strategic purposes behind the allegedly transparent, engaging, and interactive public diplomacy were evidenced through a critical analysis of the objectives, key issues, and target publics addressed and highlighted in the public diplomacy narratives on the Web. The results suggested a possible digital divide in the interactive adoption of Web public diplomacy as well as strategic motives and interests embedded in the public diplomacy communication on the Web. This study helps increase our understanding of the paradox of public diplomacy in the digital age.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.261-266
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• 2017

This study describes the design and implementation of SHF band Upconverter Digital Satellite Communication. The SHF band Upconverter unit consists of PLDROand frequency converter. In frequency converter, microstripBPF and LPF designed through the pre EMsimulation are implemented to minimize the unwanted spurious in frequency converter. Through the pre-simulation analysis ofspace environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Upconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Upconverter after production.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.845-852
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• 2000

In the 21s1 century, it may be possible to offer comprehensive service by integrating all communication media under the development of digital technology without the classification of broadcasting and communication. In addition, it will be begun to perform HDTV broadcasting by focusing on the Metropolitan area in 2001yr and will permit over 100 channels for satellite communication, thus multi-channel TV broadcasting age has come in Korea. Therefore, this study is to identify the future environment of TV broadcasting and service area in ISDB age and to present new interactive type publication satellite TV transmission system, which provides customizing type digital screen book publication, by analyzing satellite broadcasting technology to create Korean cultural area around the Korean peninsula.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2356-2376
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• 2021

In this paper, we proposed a novel modulation recognition method based on quantum elephant herding algorithm (QEHA) evolving neural network under impulse noise environment. We use the adaptive weight myriad filter to preprocess the received digital modulation signals which passing through the impulsive noise channel, and then the instantaneous characteristics and high order cumulant features of digital modulation signals are extracted as classification feature set, finally, the BP neural network (BPNN) model as a classifier for automatic digital modulation recognition. Besides, based on the elephant herding optimization (EHO) algorithm and quantum computing mechanism, we design a quantum elephant herding algorithm (QEHA) to optimize the initial thresholds and weights of the BPNN, which solves the problem that traditional BPNN is easy into local minimum values and poor robustness. The experimental results prove that the adaptive weight myriad filter we used can remove the impulsive noise effectively, and the proposed QEHA-BPNN classifier has better recognition performance than other conventional pattern recognition classifiers. Compared with other global optimization algorithms, the QEHA designed in this paper has a faster convergence speed and higher convergence accuracy. Furthermore, the effect of symbol shape has been considered, which can satisfy the need for engineering.

• Convergence Security Journal
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• v.21 no.4
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• pp.15-22
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• 2021

Security of voice communication content in the military's voice communication network will be essential. There is no proposed study on voice data security of military communication networks, but security of voice data will be essential when communicating. This paper is about to an encryption/decryption technique of digital voice data to provide security in case of voice calls in a military communication network. In addition, by using a symmetric key algorithm using AES, a secret key is required, and it has the function of transmitting this key to the receiving end before setting it as a voice call, solving the difficulty of distributing the secret key. This paper proposes a security technique for digital voice data that applies a synchronous stream encryption method that is relatively easy to restore synchronization even in the event of loss of synchronization among stream encryption techniques.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.12-17
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• 2018

This study describes the design and implementation of Antenna for Digital Satellite Communication. The Antenna unit for SHF band consists of Reflector, Septom Polarizer, Feed Horn and Support Frame etc. Thought analysis of space environment before production, the possibility of the malfunction of equipment minimized and we designed a reliable Antenna through simulation for vibration and thermal analysis generated during the launch, and compared pre-simulation of main performance results to test results about main performances of Antenna after production. After fabricating the antenna, the maximum gain of the antenna main beam is 36.5dBi, which satisfies the requirement of 35dBi or more, and it also satisfies the requirement of -20dB for return loss of less than -24dB. Also, the isolation of the transmission and reception of the antenna is -22.6dB or less, which satisfies the requirement of -20dB or less. The antenna for digital satellite communication described in this paper can be used in the satellite field of geostationary earth orbit and low earth orbit requiring high reliability in the future.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.921-926
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• 2009

After the scientific development of human history, numerous images have been developed and expanded in digital media as a communication tools. Image digital media make communication closer between sender and receptor. The image digital media which has been developed with the change of technology and media transformation have shortened visual information transportation and the time as well by combining the sense of visual and audio. Motion graphic field has been emerged as the type of image digital media development. The development of motion graphic make possible for the expressive effect and dynamic image technique which is impossible by the existing media type. Especially, it is applied to various field such as the title of movie, TV program, and advertise or music video etc. These image expression techniques are stimulating acceptor's emotion to take a role of emotion communication function also. This study aims to find the characteristics motion graphic of which how influence as an effective communication tool as important role to the receptors, and the examine the effect and application of motion graphic to the receptors as a emotion communication tool by case study.