• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.481-492
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• 2008

With the advancement of the Internet and networks, the combination of wired/wireless technologies is spreading rapidly since it enables the creation of new services and provides new features to both users and service providers. In such wired/wireless integrated services, network integration is very important because such systems are integrated by a linkage between heterogeneous networks and they involve an integration of transmission technologies across networks. In this situation, existing security and communication technologies are unsuitable since the network are integrated with heterogeneous networks. The network may also have several security vulnerability. Also, form of service that users offer will be service for roaming user. In these service, we must provide fast authentication and security at roaming. Therefore in this paper we proposed roaming and AAA mechanism in heterogeneous network environment. Our system provides secure communication and efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.104-107
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• 2014

Nowadays, smart devices such as smart phones, tablets PC, etc... are exchanging messages using WLAN(Wi-Fi) technologies for sending and receiving messages. With the growth of the smart devices users, the WLAN (Wi-Fi) medium communication could be loaded and then the Quality of Service is undesirable. Currently, there are five types of Wireless LAN such as802.11 a / b / g / n / ac supporting the communication between smart devices and the most used it WLAN 802.11n. Unfortunately, if the WLAN 802.11n is being used by a lot of users, there is poor Quality of Service due to the interference. In this paper, we analyze the Quality of Service provided by the 802.11n and compare with the next generation of wireless 802.11ac.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.170-178
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• 2011

In this paper, a research was performed to develop a wireless measurement system for bridge monitoring using MEMS sensor and bluetooth wireless communication module. First, in order to prove the suitability of MEMS sensor for the bridge measurement, its ranges of measuring acceleration and of frequency response were experimented. Also, the quality of wireless communication was tested by an experiment on long-distance communication for the knowledge of maximum communication distance, and also by an experiment on the data transmit-receive capability both inside and outside of a steel box bridge. Later, placing the wireless acceleration sensor system that had been developed in our lab on a bridge in public service, we acquired vibration data from the bridge under traffic load and analyzed its dynamic characteristics in realtime. For the analysis of the data, NExT & ERA algorithm were employed. The result of analysis was compared to the FE analysis of the same bridge, and the comparison made it possible to evaluate the performance of wireless acceleration sensor system. As a result, it was proven that the wireless acceleration sensor system developed with the use of MEMS sensor and bluetooth wireless communication module could be effectively applied to the measurement of structure whose vibration feature was low frequency like a bridge.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.225-232
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• 2009

Increasing the number of the solitude old person maintain a healthy lifestyle, the research for the emergency detection and life monitoring is required. In this paper, the wireless sensor network technology is utilized to design a silver-care service model in the area of emergency silver generation activities. The service model proposed in this paper acquired by using mobile devices to access silver-care service with the network information obtained through video monitoring and sensing. Also, Proposed model, based on wide-area network connected with the best wireless network of the PDA and mobile phones for the solitude old person.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.4
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• pp.657-662
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• 2019

The power consumption of wearable sensors and electrocardiogram regulators should be very low to extend the network lifetime and anticipated QoS( : Quality of Service) control such as error correction and authentication of data processed by WBAN( : Wireless Body Area Network) nodes is important. Therefore, QoS control is the most urgent concern to implement WBAN in health monitoring regulations. For optimal QoS control, we compare the energy efficiency and the average number of transmissions with IEEE 802.15.6 and the error correction method considering energy efficiency. The performance of the proposed error correction technique shows that the energy efficiency and the transmission rate are improved by adjusting the coding rate appropriately using the channel estimation.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.4
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• pp.107-114
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• 2014

Things in the IoT(Internet of Things) make various services by exchanging information over networks. The IoT includes many types of WSNs(Wireless Sensor Networks) that consists of spatially distributed wireless sensor nodes and operates with the various purposes with useful technologies such as identification, sensing and communication. Typically, Zigbee network composed of low-cost and lowpower devices is mainly used for wide-area monitoring and remote device control systems. The IoT composed of various WSNs cannot interoperate among networks because of heterogeneous communication protocol and different data representation of each network, but can facilitate interconnection and information exchange among networks via the DDS, which is communication middleware standard that aims to enable real-time, high performance and interoperable data exchanges. In this paper, we proposed design of Zigbee Adaptor for two-way interoperation and data exchange between Zigbee network and other networks in the IoT. Zigbee Adaptor communicates with Zigbee network according to the Zigbee protocol and communicates with external networks via DDS. DDS-based Zigbee Adaptor can facilitate interoperation between a Zigbee network and external networks by systematic cooperation among its components.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.181-187
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• 2005

This paper proposes and implements a service model to transfer messages safely for PDA on CDMA wireless network and a secure massage transfer protocol which considers characteristics of PDA. Proposed service uses SMS(Short Message Service) connect to a off-line client device with the wired network for data communication. After receiving SMS message, client device processes the SMS message and creates a data channel through RAS(Remote Access Service), then the data of the server can be pushed to clients. The implemented security protocol can provide safe data transmission on each communication line through two way channels(SMS and data). Also, by using security nonce table, this protocol can reduce a number of transmissions for exchanging a safe session key, so intensity of encryption can be increased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.495-498
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• 2007

Recently, as REID Tag and Reader has been attached to, and wireless internet has been added to a mobile phone, the commercialization of Mobile RFID Service to obtain necessary information on daily life and use various applications by using mobile communication infra is drawing nearer. A new returns by Mobile RFID Service can be expected, however, the exact demand forecasting for the Mobile RFID Service is essential to induce mass investment from related communication enterprises. This study tries to get a foothold in enlarging the investment from related communication enterprises through demand forecasting for the Mobile RFID Service and to be helpful to the decision on their investment by predicting the demand on the service various Mobile RFID Service Models.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.64-68
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• 2007

Commercial WiBro and 3G HSDPA services are launched last year in order to provide high speed wireless Internet access and multimedia service. Currently mobile communication service providers concentrate on the deployment of indoor mobile network since indoor traffic is remarkably increased. For fine indoor wireless communication, an installation of access point system via Public IP network which is called Femtocell is required. The development of indoor Femtocell system must be considered in the viewpoint of low hardware complexity, cost reduction, interlocking with WiBro/HSDPA network without change of network component and easy element management. In this paper, we review the implementation issue and technology of dual mode AP which provides WiBro and HSDPA signal to the user simultaneously. Especially, we describe on the HSDPA Femtocell standardization status and possible 3 types of HSDPA communication module development design. Furthermore we analyze the merits and demerits of each HSDPA Femtocell design type and propose a system which enables handover between indoor HSDPA Femtocell and outdoor commercial HSDPA mobile network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.37-42
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• 2012

LED is just a semiconductor which can produce light. Currently, there are active research works on LED lighting technologies according to the growth of energy-saving environmental industry. Especially, LED communication is one of the active research works in these fields. In this paper, we design a LED communication-based multi-hop transmission wireless network system. The designed system consists of a transmission circuit system(transmitter) using LED and a receiving circuit system(receiver) using PD(photo detector) and OP-Amp, and relay system which can support multi-hop wireless network service with PD, OP-Amp, and LED, respectively. The experiments for the designed system are performed as follows. One computer is connected at the end of transmitter and receiver, respectively. There are two relays between transmitter and receiver, and text files are transmitted continuously by using text transmission programming. In this experiment, we test the performance with various baud rates, transmission ranges.