• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.6
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• pp.503-511
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• 2014

In this paper, a novel, real-time video stitching algorithm in an H.264/AVC compressed domain is proposed. This enables viewers to watch multiple video contents using a single device. The basic concept of this paper is that the server is asked to combine multiple streams into one bit-stream based in a compressed domain. In other words, this paper presents a new compressed domain combiner that works in boundary macroblocks of input videos with re-calculating intra prediction mode, intra prediction MVD, a re-allocation of the coefficient table, and border extension methods. The rest of the macroblocks of the input video data are achieved simply by copying them. Simulation experiments have demonstrated the possibility and effectiveness of the proposed algorithm by showing that it is able to generate more than 103 frames per second, stitching four 480p-sized images into each frame.

• Journal of Communications and Networks
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• v.10 no.4
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• pp.455-464
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• 2008

To provide network services consistently under various network failures, enterprise networks increasingly utilize path diversity through multi-homing. As a result, multi-homed non-transit autonomous systems become to surpass single-homed networks in number. In this paper, we address an inevitable problem that occurs when networks with multiple entry points deploy firewalls in their borders. The majority of today's firewalls use stateful inspection that exploits connection state for fine-grained control. However, stateful inspection has a topological restriction such that outgoing and incoming traffic of a connection should pass through a single firewall to execute desired packet filtering operation. Multi-homed networking environments suffer from this restriction and BGP policies provide only coarse control over communication paths. Due to these features and the characteristics of datagram routing, there exists a real possibility of asymmetric routing. This mismatch between the exit and entry firewalls for a connection causes connection establishment failures. In this paper, we formulate this phenomenon into a state-sharing problem among multiple fire walls under asymmetric routing condition. To solve this problem, we propose a stateful inspection protocol that requires very low processing and messaging overhead. Our protocol consists of the following two phases: 1) Generation of a TCP SYN cookie marked with the firewall identification number upon a SYN packet arrival, and 2) state sharing triggered by a SYN/ACK packet arrival in the absence of the trail of its initial SYN packet. We demonstrate that our protocol is scalable, robust, and simple enough to be deployed for high speed networks. It also transparently works under any client-server configurations. Last but not least, we present experimental results through a prototype implementation.

• Journal of the Korea Society of Computer and Information
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• v.29 no.3
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• pp.83-90
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• 2024

In this paper, we propose a solution to apply a proximity voice dialog system to voice dialog technology, one of the interaction systems in multimedia environments. A voice dialog between multiple users in a multimedia space is designed by adjusting the volume of the voice according to the distance between the user avatars and muting the user who is beyond the audible distance. The main feature of this research is a reliable UDP-based active server system that delivers low-quality voice data to users who are far away based on distance and does not transmit voice data to users who enter the inaudible area for economic development. The performance of the proposed system was measured in a previously completed project based on the Unity game engine, and it is expected that the system proposed in this research will be actively used in environments that provide interaction between multiple users such as met averse content and real-time battle action games.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.179-185
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• 2010

In ubiquitous society, there have been increasing demands on safety and security issues with infrastructures and services based on wireless technology. In this paper, we first introduce our own developed technology Binary CDMA to meet those demands. Then we present a wireless A/V surveillance system based on the Binary CDMA technology. The implemented wireless A/V surveillance system is composed of wireless terminals, wireless multiple channel processors, and an A/V management server, and the system gives a hint that the Binary CDMA technology can be adopted in practical ubiquitous systems to handle safety and security issues.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.432-438
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• 2010

In this paper, we propose a system which can perceive status of semiconductor equipment and evaluate its performance. The proposed system acquires the information such acceleration, pressure, temperature and gas sensors in the surrounding semiconductor equipment. After acquiring information, it is sent to server through multi hop transmission. The transmitted data generates 3 steps alarm using context-aware algorithm of unit or multiple event. From the experiment's result of the proposed system, we confirm that the reliability and efficiency of information is more improved about 80% than a system that doesn't use context-aware algorithm. Moreover, this system can be effective status monitoring of semiconductor equipment because lots of client nodes acquire surrounding information.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.577-580
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• 2012

Communication environment has rapidly evolved into All-IP based core network, which is centered on a variety of access network, and develops into ubiquitous environment for each user due to the development of multiple interface terminals and the spread of contents usage. Especially, mobile streaming technologies and integrated authentication technologies are needed for mobile users to provide seamless mobility. The technology for seamless mobility services is an important issue. In this paper, the IEEE 802.21 MIH information server is based on the network offering handover technology between heterogeneous network.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.4
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• pp.205-212
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• 2010

In a typical data center, large numbers of IT sever racks are arranged multiple rows. IT environments, in which extensive electronic hardware is air-cooled, cooling system inefficiencies result when heated exhaust air from equipment prematurely mixes with chilled coolant air before it is used for cooling. Mixing of chilled air before its use with heated exhaust air results in significant cooling inefficiencies in many systems. Over temperatures may not only harm expensive electronic equipment but also interrupt critical and revenue generating services. Cool shield is a cost effective aisle partition system to contain the air in cold aisles and hot aisles of an IT server room. This paper focuses on the use of performance metrics for analyzing aisle partition system in data centers.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.3
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• pp.121-129
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• 2010

For the development of software industry, offers an expanded software authentication scheme caused by the unauthorized copying of software is to reduce the damage to software developers, retail sales and to promote the development of the software industry was studied. Serial Number of the current software registration is conducted in such a simple verification procedure if the Serial Number only illegal and can be installed on multiple computers, such as program code to allow third parties to enter the Serial Number, or the extract can be used without is a reality. The proposed extension to the software authentication system when you install the software, my phone authentication and MAC Address Authentication Service introduced to distinguish normal user, the user of the MAC Address of the server and software development company that was sent to the registered MAC Address of the computer to be run only by the use of genuine software and to make unauthorized copies of software generated by the software developer can reduce the damage of the proposed plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3495-3501
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• 2010

Because the application simultaneously to transmit large amounts of data (Video conferencing, Internet broadcasting, Online games etc.) to multiple users increases, the importance and utilization of group communication was greater. So the security was recognized as a important issue. To provide security in multicast environment, A study of single group management server using protocol based on Key Tree Scheme was proposed. But the paper proposes secure group key management scheme to be a relatively low-overhead. Therefore proposed paper is demonstrated to be excellent by comparing the effectiveness of existing and proposed group key management scheme.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.15-27
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• 2003

Recently, the volume of data is increasing rapidly in server for multimedia service, according to development of multimedia application environment. In recent research for storage technology the technology like of the SAN(Storage Area Network) advantages in scalibility of storage devices, and can read data from multiple disk arrays through RAID 0, 5. The RAID 0 and 5 translate to logical address to physical address using equation, but in case of adding disks at the system with equation -based mapping, the problem that we must rearrange the whole data in the previous disks happens. We use the mapping table to solve this problem in recent, but we can not load the whole mapping table in main memory because it occupies too large space. Therefore the extra I/Os are demanded to evaluate real physical address of data, so total performance of the system is degraded. In this paper, we propose the mapping method that supports the scalibility in RAID 0 or 5 system. The proposing method applies small metadata, so- called SZIT and simple equation, so it is possible that we make translate logical address to physical address rapidly and it is scalable in disk extending simultaneously Our suggesting method, if we add disks to the striping system for expanding of storage capacity, has an advantage of never stop service. So, SZlT-based mapping method can do online-disk-expanding in real-time service.