• The Journal of the Korea Contents Association
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• v.5 no.1
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• pp.89-99
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• 2005

HPI system provides 1-3 Mbps data transmission speed to terminals moving up to 60 km/sec. Since HPI supports rtPS, nrtPS, and BE services requiring different QoS, it needs an efficient scheduling method based on those different QoSs. This paper suggests an uplink scheduling method which gives priority to services in the order of rtPS, nrtPS and BE services but which reserves some bandwidth for the low priority services before it allocates the bandwidth to higher priority services. Simulation results show that it can improve the uplink performance by reserving mean transmission rate to each nrtPS terminal and by reserving bandwidth, which amounts to about 1.5 times the mean transmission rate of the whole BE terminals, to the whole BE terminals.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.102-108
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• 2018

The existing data transmission technology applied between the non-secure external internet and the secure internal business network has various problems when applied to the building facility management SCADA system control network. Traditional inter-network data transfer technologies involve high complexity and high costs because blacklist-based security techniques are applied to all data. However, whitelist-based security techniques can be applied to data distributed in Building Facility Management SCADA control systems because a small number of structured control data are repeatable and periodic. This simplifies the security technology applied to inter-network data transmission, enabling building facility management SCADA system control network deployment at low cost. In this paper, we proposed building control networks specialized in building facility management SCADA control systems by providing solutions to address and address these problems.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.94-101
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• 2007

In this paper, we propose a surveillance system using multi-person tracking in a WIPI based mobile system, which is the standard wireless internet platform. The proposed system consists of two subsystems: the person tracking system and the mobile information transmission system. The person tracking system tracks persons who invade security and the mobile information transmission system sends the tracking results from the person tracking system to the user's mobile phone. In this paper, the person tracking system tracks persons who appear on many cameras with non-overlapping views in order to achieve a wider view. The mobile information transmission system saves automatically tracked data to the owner's web server and transmits the saved data to the user's WIPI mobile phone. Therefore, whenever the user wishes to view tracked data later, the mobile system can provide the user with the tracking results by either the user selecting particular cameras or the time on the owner's mobile phone. The proposed system is a new surveillance system that transfers tracked data among cameras to the user's mobile phone in order to overcome space limitations in tracking areas and monitoring areas and spatial limitations in monitoring hours.

• Journal of Digital Contents Society
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• v.3 no.1
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• pp.47-57
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• 2002

Recently, wireless networks have been pursuing multimedia data service as voice, data, image, video and various form of data according to development of information communication technology. It guarantees cell delivery delay of real time data in efficient real time multimedia data transfer. Also, it minimizes cell loss rate of non-real time multimedia data. In the wireless ATM, there are based on Asynchronous Transfer Mode(ATM). It implies that there are various service with difficult transmission rates and qualities in the wireless communication network. As a result, it is important to find out the ways to guarantee the Quality of Service(QoS) for each kind of traffic in wireless network. In this thesis, we propose an improved TCRM scheduling algorithms for transmission real-time multimedia data service in wireless ATM Networks. We appear real time multimedia scheduling policy that apply each different method to uplink and downlik to wireless ATM network. It can guarantee QoS requirements for each real time data and non-real time data. It also deals the fairness problem for sharing the scarce wireless resources. We solve fault of TCRM as inefficient problem of non-real data by using arbitrary transmission speed and RB(Reservation Buffer) through VC(Virtual Control) and BS(Base Station).

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.133-139
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• 2017

To address the problems caused by such high installation and maintenance cost in the conventional server-based cloud systems, researches on P2P cloud storages have been conducted recently. In this paper, we propose a hierachical overlay structure that can improve the playback quality in P2P cloud storage systems for video transmission. In this structure, after we make groups by clustering the participating peers based on their similarities, we construct subgroups by geographically dividing the peers belonging to a specific group considering the physical proximities among them. Therefore, when a request for video playback is issued, we can minimize the transmission delay by selecting the source peers depending on their locality. By simulations, we show that our proposed hierarchical overlay structure considering the peers' locality outperforms the structure where source peers are selected randomly.

• Journal of Digital Contents Society
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• v.15 no.3
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• pp.319-326
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• 2014

IEEE 802.11 WLAN uses CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance) method in MAC(Media Access Control) protocol, and through the carrier sense checks whether other users use the channel during the data transmission to avoid the data collision. Currently, IEEE 802.11 standard recommends the use of a fixed threshold which gives an impact on carrier sensing range. However, the existing scheme using the fixed threshold causes the operation of network to be inefficiency owing to the mobility in MANET(Mobile Ad hoc NETwork). In this paper, we found the better network throughput to be obtained by applying the proposed scheme, which chooses properly the carrier sensing threshold and transmission rate considering SINR(Signal to Interference-plus-Noise Ratio), to the MANET.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.33-42
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• 2011

In this paper we designed and implemented a wireless communication circuit which can control the remote devices integrating RFID and ZigBee. This system unifies transmit part and receive part. And this system recognizes RFID tag data, then the recognized information is controlled by MCU, and transmitted to a remote device through the ZigBee. This is operated on TinyOS. If this system is applied to a entrance security system, it can permit/deny one's entrance as well as control the personal computer or other electronic devices. Our experiment shows the result of the recognized data transmission is very different according to a opened playground and a closed place. The data transmission time is stable in the indoor and the data transmission distance is long in the outdoor. We anticipate that our system be applied the various office oriented domains by connecting to the Wired LAN or the WLAN of IEEE 802.11x category.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.43-50
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• 2005

POS system that become that is supply net administration and computerization fetters of customer management that become point in istribution network constructed database and use XML-Encryption that is certificate techniques of PKI and standard of security for security that is XML's shortcoming and design distributed processing POS system using XML for data integration by introduction of Ubiquitous concept. This POS system has four advantages. First, Because there is no server, need not to attempt authentication and data transmission every time. Second, can integrate data base by XML and improve portability of program itself. Third, XML data in data transmission because transmit data after encryption data safe .Fourth, After encode whenever process data for data breakup anger of POS system client program and elevation of the processing speed, transmit at because gathering data at data transmission.

• The Journal of the Korea Contents Association
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• v.13 no.1
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• pp.40-47
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• 2013

To verify the condition of patients moving in the medical center like hospital needs to be consider the various wireless communication network protocols and network components. Wireless communication protocols such as the 802.11a, 802.11g, and direct sequence has their specific characteristics, and the various components such as the number of mobile nodes or the distance of transmission range could affects the performance of the network. Especially, the network topologies are considered the characteristic of the brain wave(EEG) since the condition of patient is detected from it. Therefore, in this paper, various wireless communication networks are designed and simulated with Opnet simulator, then evaluated the performance to verify the wireless network that transmits the patient's EEG data efficiently. Overall, the 802.11g had the best performance for the wireless network environment that transmits the EEG data. However, there were minor difference on the performance result depends on the components of the topologies.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.111-119
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• 2007

Sensor networks are needed for special purposes such as collecting or transmitting information by using sensor devices, for which various routing protocols have been proposed. Among existing protocols, the modified PEGASIS routing technique is known to be effective when applied to cases with directional transmissions of data. However it does not consider recovery from errors or guaranteeing stability in data transmission, while sensor devices performing repetitive relays and controls are prone to errors. In this paper, a double relay routing protocol for Zigbee based sensor networks where data are transfered reliably with a linear direction. The proposed protocol is effective in the sense that it secures the relaible transmission of data with minimal energy consumption based on a directional data transfer. A streetlight control system has been presented as an application of the proposed protocol.