• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.59-64
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• 2023

Fire and disaster broadcasting systems are divided into analog, digital, and network-based digital public address systems, and important specifications in network-based digital public address systems are low-latency audio, high sampling rate, and multi-channel input and output. In the past, it has been widely used to the AoE method for distinguishing based on the MAC address of the data link layer. However, this method has a problem of increasing complexity and cost. This proposal is an AoIP/UDP method, which allows communication to be easily distinguished by IP address without the need for a separate redundant network, so that the network can be freely used and configured, and cost can be reduced by reducing complexity. After implementing the AoIP/UDP method, the experimental results showed that the cost was improved with the equivalent performance with 2.66ms latency.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.57.4-57.4
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• 2019

BITSE is a project of balloon-borne experiments for a next-generation solar coronagraph developed by a collaboration with KASI and NASA. The coronagraph is built to observe the linearly polarized brightness of solar corona with a polarization camera, a filter wheel, and an aperture door. For the observation, the coronagraph is supported by the power distribution unit (PDU), a pointing system WASP (Wallops Arc-Second Pointer), telemetry & telecommand system SIP (Support Instrument Package) which are developed at NASA's Goddard Space Flight Center, Wallops Flight Facility, and Columbia Scientific Balloon Facility. The BITSE Command and Data Handling (C&DH) system used a cost-off-the-shelf electronics to process all data sent and received by the coronagraph, including the support system operation by RS232/422, USB3, Ethernet, and digital and analog signals. The flight software is developed using the core Flight System (cFS) which is a reusable software framework and set of reusable software applications which take advantage of a rich heritage of successful space mission of NASA. The flight software can process encoding and decoding data, control the subsystems, and provide observation autonomy. We developed a python-based testing framework to improve software reliability. The flight software development is one of the crucial contributions of KASI and an important milestone for the next project which is developing a solar coronagraph to be installed at International Space Station.

• Smart Media Journal
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• v.13 no.1
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• pp.52-59
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• 2024

This paper proposes a plan to improve the reception radio environment of the mobile terminal and maintain a constant reception electric field by using small cells in a small closed environment. In order to configure an efficient communication infrastructure for small cells, both ends of wireless transmission and reception of an Ethernet-based wireless video recording system are connected using an L2 switch. The small cell connected to the receiving side L2 switch shares the wireless network section of the wireless video recording system and connects to the transmitting side L2 switch. After that, when it is normally linked to FMS, a management system for small cells, through the Internet network, the output of small cells is checked. In order to verify the results, a proposed network is formed on the elevator inside the building with a poor radio wave environment, and the radio wave environment is measured before and after the small cell application in the section where the elevator operates. As a result, the main parameters of the radio wave environment in all sections of the elevator are improved, as well as a constant receiving electric field strength within the moving elevator.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.49-56
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• 2004

The performance of the multiprocessor systems is limited by the several factors. The system performance is affected by the processor speed, memory delay, and interconnection network bandwidth/latency. By the evolution of semiconductor technology, off the shelf microprocessor speed breaks beyond GHz, and the processors can be scalable up to multiprocessor system by connecting through the interconnection networks. In this situation, the system performances are bound by the latencies and the bandwidth of the interconnection networks. SCI, Myrinet, and Gigabit Ethernet are widely adopted as a high-speed interconnection network links for the high performance cluster systems. Performance improvement of the interconnection network can be achieved by the bandwidth extension and the latency minimization. Speed up of the operation clock speed is a simple way to accomplish the bandwidth and latency betterment, while its physical distance makes the difficulties to attain the high frequency clock. Hence the system performance and scalability suffered from the interconnection network limitation. Duplicating the link of the interconnection network is one of the solutions to resolve the bottleneck of the scalable systems. Dual-ring SCI link structure is an example of the interconnection network improvement. In this paper, I propose a network topology and a transaction path algorism, which optimize the latency and the efficiency under the duplicated links. By the simulation results, the proposed structure shows 1.05 to 1.11 times better latency, and exhibits 1.42 to 2.1 times faster execution compared to the dual ring systems.

• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.277-287
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• 2006

Most of the existing broadband access networks based on DSL, cable modem, and Ethernet support the best-effort internet access service, and adopt the flat rate pricing mechanism. It is almost impossible to provide the differentiated communication services, in current broadband access networks, for the different users and/or the different application services. Currently, however, the advances in multimedia, communication, and security technologies push the interactive and/or streaming multimedia services and VPN services to be widely deployed over Internet, and they require more QoS-sensitive services than the best-effort service. Though various QoS technologies such as RSVP-based IntServ and DiffSern were already developed and under standardization in Internet world, it is impractical to replace the existing QoS-unaware access networks with the QoS-enabled ones at a time to deploy QoS-sensitive services. In this paper, after analyzing current broadband access network architectures and the status of QoS support, we propose a practical approach to support multimedia QoS in the broadband access networks. The approach will be based on the integration of the differentiated pricing and the DiffServ technology. And it will be a step-wise approach to support backward compatibility with the legacy broadband access networks as much as possible.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.7-16
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• 2006

IPTV is referred to the service which provide integrated IPTV services for providing video, 10/100-Mbit/sec Internet, voice, video-on-demand (VOD), and other broadband applications including home security, video conferencing, and telemedicine. All services are integrated into an IP (Internet Protocol) architecture designed specifically for Gigabit Ethernet FTTH systems, HFC or xDLC. It is absolutely necessary that telecon operators provide IP video delivery platforms that enable service providers to transform their business. With their own products, they can better manage their existing services and generate new revenues from broadcast TV, movies on demand and multimedia. Triple-play is a combination of broadcast, telephony and broadband services offered through IPTV networks. With cable operators allowed to offer a triple-play bundle, the nation's telecom operators are beginning to get a little anxious. Cable operators assert that triple-play is a must-have and natural extension of the cable service bundle. The Korean Cable TV Association asserts that the triple-play model is of paramount importance to the cable industry's future growth. But the telecom sector considers itself unfairly disadvantaged, saying they cannot compete until regulatory issues are resolved. The start of web-based television in Korea may still be some time off with a confrontation between the nation's IT regulator and broadcasting sector over the service's legal boundaries shows no signs of being resolved my time soon. korea should be is the fastest-growing provider of IPTV solutions in the industry, with over worldwide customers.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.58-68
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• 2010

In this paper, we propose an efficient link protection switching scheme for provider backbone bridge systems with a spanning tree for backup links exclusively, and evaluate its performance. The proposed scheme offers guaranteed QoS flows even when a link fault occurrs in the primary link by flooding the flows over the profiled spanning tree. The flooding mechanism over the spanning tree can also provide low latency and remove the loopback flows. We also derive the efficiency of bandwidth usage for the normal flows and the number of lost frames during the link restoration. For evaluating its feasibility, we implement a prototype of PBB-TE systems based on the Linux bridge codes, which can support both link protection switching capability with CCM and MAC-in-MAC encapsulation. A related protocol analyzer is also developed. One can see that the proposed scheme and the prototype can be useful for developing carrier class Ethernet systems based on PBB-TE.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.1 no.1
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• pp.6-25
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• 2002

In this paper, we have implemented UPnP Devices which emulate a Control Point, a Light Controller, and a Digital TV. The Control Point has been developed on Linux host system by using C language. The UPnP Devices emulating the Digital TV and Light Controller are running on embedded linux developer board. For the development of UPnP Devices, UPnP SDK API Vl.04 made by Intel Co. Ltd. has been ported on Assabet Linux Reference board to implement the UPnP protocol. After we analyze and design some services of Digital TV device, we have applied UPnP Device program to those devices. UPnP SDK vl .04 consists of APIs which support HTTP, SSDP, SOAP, GENA and XML DOM Level-1 that are cores of UPnP protocol. The C program written for the UPnP Control Point has been compiled and executed on Linux-based PC. The embedded system running on Embedded Linux OS has been connected all together through Ethernet which allows IP-based communications. Under this environment, the UPnP programs are being executed on each device. Control Point, when in operational mode, discovers UPnP Devices on the network and displays the device list on the consol. By selecting one of the functionalities of the device services that are displayed on the Control Point, the controllability has been accomplished. The experiment that we performed in this thesis have revealed that the Control Point and UPnP Devices have supported the protocols including SSDP, SOAP, GENA, and DHCP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2337-2342
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• 2010

There is a vast field of application for RFID(Radio Frequency IDentification) technology. In the case of hospitals, RFID can be used for organizing patient data. Generally, patient data has been handled with medical cards. In order to look up data about a patient, the medical card would have to be found first, within a lot of other medical cards, by hand or with a computer. This is a very inconvenient system. Also, if the card is searched by the name of the patient, fatal medical accidents may occur in cases of mix-ups. If remote RFID Tag monitoring systems are applied in this case, the patient data would be accessible in the hospital. This article will discuss the grafting of RFID systems and wireless data communicating technology. The EM4095 chip, which uses 125KHz carrier waves was used in this study. And a Bluetooth module was added for wireless data communication. The ATMEGA128 microcomputer was used to control the RFID system and wireless module. A LCD monitor was connected to the extension port for nurses to view patient data, and also, the same information was displayed on PC monitors for doctors to see. The circuit was designed to consume minimal amounts of electricity for portability, and to transmit Tag ID's in environments with a lot of noise. The article is concluded with a diagram of the whole system, and performance of each data transmitting section has been analyzed.

• 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.