• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.496-498
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• 2013

Smartphone is becoming popular from younger generation to old generation because of its convenience. Generalizing use of smartphone, it was being developed and released for education application from based on PC to smartphone. in this paper, this application was designed and developed an helpful and enjoyable application for those who very interested child education. in this paper, suggestion of the propose of education is provided on service various contetns. The children can do implement information about organism characters living in sea just selected them they want without going to sea and aquarium whenever they want. this application is implemented that children also can be relearning the organism characters by quiz that already learned them before, and developing artistic sense, creativity and imagination by coloring exercise.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.482-484
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• 2017

Over the past 70 years, movies and television have revolutionized the way people communicate. However, even with this development, TV has been used only as a means of communication targeting an unspecified number of people due to the restriction of media such as radio waves and movies. However, the development of the Internet and online video has come to a time when 100 million people watch YouTube videos uploaded from the other side of the world by eliminating these restrictions. The message that you want to deliver now can be delivered to anyone, but making the image with these messages remains the last obstacle to communication. To solve these problems, we implemented a web application and a video production program through AWS. This system basically provides the administrator with the video production through the easy interface, the information management and the program on the server on the internet through AWS, the assigned lecture including the computer and the smart phone, the learning materials, And implemented to increase the efficiency of educational video production service.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.268-271
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• 2018

Smart Airport which applies the new ICT technologies to the airport is a future airport to provide convenient and safe services for passengers who are airport users, and promote the efficient management of the airport system in point of airport operator's view. The ranges of smart airport include the overall area of the airport like land side, terminal, and air side. In this paper, we propose a technical solution for airport process of terminal providing passenger convenience in various ranges for smart airport realization. Self-service such as web or mobile check-in, self check-in/tagging/back drop/boarding etc. should be strengthened to smartize the airport process and technologies such as automatic immigration, smart security search and automatic AI-based baggage search should be applied. In this paper, we explain the concept of smart airport and smart process, and then propose technical considerations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1139-1146
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• 2004

An abrupt increase of traffic-load in cellular CDMA systems can cause overload, as a result, degrade the quality of service (QoS) and the spectrum utilization due to lacking radio resources in base stations. In this paper, we propose a joint coverage and resource management (JCRM) scheme which can improve the QoS degradation and the spectrum utilization. The JCRM scheme hands over the overloaded traffic to neighboring cells by virtually reducing overloaded cell coverage and extending neighboring cell coverage, as well the scheme allocates radio resources based on the necessary handover probability. The proposed scheme can be applied to the existing cellular CDMA systems as well as adaptive coverage management schemes for next generation mobile communication systems.

• Journal of Communications and Networks
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• v.13 no.1
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• pp.32-42
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• 2011

Frequency reuse among relay stations (RSs) in a down-link access zone is widely adopted for throughput enhancement in IEEE 802.16j relay networks. Since the areas covered by the RSs or the base station (BS) may overlap, some mobile stations (MSs) at the border between two neighboring transmitting stations (RS or BS) using an identical frequency band may suffer severe interference or outage. This co-channel interference within the cell degrades the quality of service (QoS) fairness among the MSs as well as the system throughput. Exclusive use of a frequency band division (orthogonal resource allocation) among RSs can solve this problem but would cause degradation of the system throughput. We observe a trade-off between system throughput and QoS fairness in the previously reported schemes based on frequency reuse. In this paper, we propose a new frequency reuse scheme that achieves high system throughput with a high fairness level in QoS, positioning our scheme far above the trade-off curve formed by previous schemes. We claim that our scheme is beneficial for applications in which a high QoS level is required even for the MSs at the border. Exploiting the features of a directional antenna in the BS, we create a new zone in the frame structure. In the new zone, the RSs can serve the subordinate MSs at the border and prone to interference. In a 3-RS topology, where the RSs are located at points $120^{\circ}$ apart from one another, the throughput and Jain fairness index are 10.64 Mbps and 0.62, respectively. On the other hand, the throughput for the previously reported overlapped and orthogonal allocation schemes is 8.22 Mbps (fairness: 0.48) and 3.99 Mbps (fairness: 0.80), respectively. For a 6-RS topology, our scheme achieves a throughput of 18.38 Mbps with a fairness of 0.68; however, previous schemes with frequency reuse factors of 1, 2, 3, and 6 achieve a throughput of 15.24 Mbps (fairness: 0.53), 12.42 Mbps (fairness: 0.71),8.84 Mbps (fairness: 0.88), and 4.57 Mbps (fairness: 0.88), respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.613-619
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• 2012

The Long Term Evolution (LTE) system is already able to provide a background of variety services for mobile users with multimedia services such as audio, video, and data. In fact, the High Speed Packet Access plus (HSPA+) solution can greatly enhance bit rates on down-link. However, the supporting for multimedia applications with different QoS (Quality of Service) requirements is not devised yet. Hence, in this paper we propose an effective packet scheduling algorithm based on Proportional Fairness (PF) scheduling algorithms for the LTE. In this proposed packet scheduling scheme, we optimized instantaneous user data rates and the traffic class weight which prioritize user's packets. Finally, we evaluated and showed the performance of the proposed scheduling algorithm through simulations of multimedia traffics being transmitted to users over LTE links in a multi-cell environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.27-34
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• 2010

As VoIP systems move to wireless environments with much higher average packet loss rates than wired networks, it becomes less possible for the network to assure a reasonable QoS. So, real-time quality monitoring for mobile VoIP applications is an important issue to be explored. In this paper, we explore perceptual quality dependency on two parameters: the burst loss rate and average burst length. Also, we propose a simple 'moving average' approach with $\alpha$ aiming to measure those parameters on real-time basis. In order to find how accurately the two parameters measured estimate the real perceptual quality, we compare actual measured PESQ scores with estimated value by matching the measured quality metric to the trained MOS table. Finally, we propose the quality-based accounting system, which can set obvious continuities between quality and billing.

• Journal of Digital Contents Society
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• v.14 no.2
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• pp.191-197
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• 2013

To complete the "anywhere" mobile service there should not be shaded areas. However, it is never economical to deploy BS's (Base Stations) in a low population density area due to the low resource utilization. We propose a design technique to install RS's(Relay Stations) which are cheaper than BS's and find the condition in which the proposed technique is acceptible. The proposed design technique aims to allocate the frequency and time resources to RS's to minimize the transmission rate degradation due to interferences between RS's as well as to maximize the parallelism in transmission. We showed by simulation that the proposed technique achieves cost benefits when the expected traffic is less than 20.32 percent of the total BS capacity. The proposed technique is compatible with the IEEE 802.16j, thus can be extended to multi-hop configuration.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.269-275
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• 2014

The DAB system was designed to provide CD quality audio and data services for fixed, portable and mobile applications with the required BER below $10^{-4}$. However for the T-DMB system with the video service of MPEG-4 stream, BER should go down $10^{-8}$ by adding FEC blocks which consist of the Reed-Solomon (RS) encoder/decoder and convolutional interleaver/deinterleaver. In this paper we propose two types of turbo coded T-DMB system without altering the puncturing procedure and puncturing vectors defined in the standard T-DMB system for compatibility. One(Type 1) can replace the existing RS code, convolutional interleaver and RCPC code by a turbo code and the other one (Type 2) can substitute the existing RCPC code by a turbo code. Simulation results show that two new turbo coded systems are able to yield considerable performance gain after just 2 iterations. Type 2 system is better than type 1 but the amount of performance improvement is small.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.195-201
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• 2017

Urbanization and industrialization have led to a severe deterioration in urban air qualities. As an air pollution is closely associated with human health, citizen has a growing concern about the air quality policy to improve their residential environment. Due to the recently advance in web- and mobile computing technologies, citizens can easily access various air quality information and public authorities utilize the social media service to communicate citizens with air quality issues. Also citizens' participation and role has been increased to improve urban air qualities. Thus, to meet the technical and societal changes, a GIS-based air quality information system is developed based upon the Ubiquitous Public Access (UPA) model in ISO19154. The proposed system employs the context information model to provide air quality information depending on citizens' health conditions and locations. Also, citizens can present their perceptions of an air quality at their current location Public authorities can thus utilize the citizens' perceptions when establishing new air quality policies.