• Journal of Biomedical Engineering Research
• /
• v.19 no.1
• /
• pp.19-24
• /
• 1998

The main goal of this paper is to propose and to test a radio protocol based CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) for the purpose of enhancing the existing medical information system. The feature of the new medical information system, Medical Application Radio System(MARS), which operating in real time is the transmission of medical information in bi-direction between the hospital control office and patients mobile stations. MARS monitors patients linked to the network by radio and provides quick alarm, flexible documentation capabilities, asnd fast treatment for the analysis of collected medical data. The existing medical information system, radio telemetry system which transfers the message of patients to the CAP(Central Access Point) unit in one way at the speed of 9.6Kbps and operates a channel frequency bandwidth. To verify the Performance of the proposed system, we have performed the numerical analysis and have implemented a test system which consists of the 2.4Ghz radio transceiver and personal computer.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.179-186
• /
• 2012

Nowadays, the multihomed host equipped with multiple network interfaces has been interested research in next generation wireless network, because the mobile users expect that they can be able to access services not only anywhere, at any time and from any network but also simultaneously. This paper addresses the mobility simulation model of the multihomed node for supporting MIPv4 and MIPv6 function in an interworking of Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11 WLAN. The multihomed node with two air interfaces has been developed based on WiMAX and WLAN workstation node model in simulation software. The main point of the developed model is to support both MIPv4 and MIPv6 function, and provide network selection policy for the multihomed node between WiMAX and WLAN network. Based on the received Router Advertisement along with the interface number, we can manage the access interfaces in ordered list to make handover decision while the multihomed node is moving. In the end of this paper, the simulation scenarios and results are shown for testing MIPv4 and MIPv6 function.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.7
• /
• pp.33-40
• /
• 2010

The hand over between different radio access networks, especially where their coverage overlaps, suffers various complications since the different access networks provide different service characteristics. In this paper, it is about the system which can control the wireless LAN network management system and the wireless LAN access point of variety vendor which is in different areas. Successful development of mobile sink wireless LAN network management system which supports multi-vendor devices and have center-local interoperability structure. In proposed system, speed of the mobile station give about 10% improvement when the map domain size is 5 than the existing system. Through a data plane and management system of message way, it give a stability system and consistency network.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.9
• /
• pp.43-54
• /
• 2013

This study proposed a new embankment stability control method to analyze the measurement data on the slope activities of the soft ground, using the Stability Control Index (SCI) obtained from the p-q stress paths. In order to validate this new technique, the data from triaxial compression tests (CU) and field measurement were compared. SCI is calculated from the current path of the effective stress points ($p^{\prime}=p-{\Delta}u$) using the relative position between the Total Stress Path $p_{max}$ and the point of $k_f$ line $p_f$. From this result, the point of effective stress $p^{\prime}(=p-{\Delta}u)$ will have access to the point $p_f$ of $k_f$ line when the pore water pressure occurs or the point of total stress pass $p^{\prime}_{max}$ when the pore pressure dissipates. Thus, the Stability Control Index (SCI) can evaluate quantitatively the safety of embankment from the relative position of the effective stress path.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.177-181
• /
• 2004

It is as research about embodiment of MAC algorithm that is point of wireless LAN technology that is radio skill that is receiving present head of a family footlights, and embodied MAC that is algorithm that control modem Rf and host interface to level that existent common use radio AP and send-receive of high speed are available that embody function that is presented to IEEE 802.11 specs using H/W and S/W. When embody actually, tested module that embody actually using module modem and RF part because test is impossible after have common use product. Also, module that embody actually designed, and is expected to be utilized in radio LAN system construction of high speed late considering CRC and FCS ewer on channel.

• The Journal of Korean Association of Computer Education
• /
• v.13 no.6
• /
• pp.91-98
• /
• 2010

NAC(Network Access Control) has been developed as a solution for the security of end-point user, to be a target computer of worm attack which does not use security patch of OS and install Anti-Virus, which spreads the viruses in the Intra-net. Currently the NAC products in market have a sufficient technology of pre-connect, but insufficient one of post-connect which detects the threats after the connect through regular authentication. Therefore NAC users have been suffered from Zero-day attacks and malware infection. In this paper, to solve the problems in the post-connect step we generate the normal behavior profiles using the traffic information of each host, host information through agent, information of open port and network configuration modification through network scanner addition to authentication of host and inspection of policy violation used before. Based on these we propose the system to detect the hosts infected malware.

• Journal of Digital Contents Society
• /
• v.19 no.8
• /
• pp.1545-1554
• /
• 2018

In order to support the mobility of the wireless devices, at least two APs (Access Points) must be arranged in a single AP area to maintain communication area. In the WLAN (Wireless LAN) environment, seamless handover is one of the most important issues in terms of effective utilization of wireless networks and maximization of services for users. On the other hand, SDN (Software-Defined Networking), which is emerging rapidly in recent years, is revolutionizing network management in terms of flexibility, fine control, and convenience. SDN originally reduces latency time or increases network robustness by real-time flow table control reducing or bypassing paths between switches in LAN-based data centers. In this study, we apply OpenFlow, a SDN platform focused on wired LAN, to a dense WLAN environment using legacy APs to implement and evaluate seamless handover for streaming services of digital contents.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.4B
• /
• pp.192-198
• /
• 2008

In this paper, we propose a scheme that improves the transmission performance of realtime multimedia data in wireless Local Area Network (LAN) environment, through the dynamical control of Transmission Opportunity (TXOP) period of the IEEE 802.11e HCCA Medium Access Control (MAC). The existing schedulers which determine the frame transmission time and its duration could not appropriately cope with the change of physical transmission rate, since the TXOP period has remained unchanged with the change of transmission rate of the wireless station. Our scheme is devised to keep the transmission performance of real-time multimedia data effectively unchanged by making TXOP period be extended when the transmission rate gets reduced. The proposed scheme is experimented along with IEEE 802.11e reference model using NCTUns simulator, which shows that the multimedia data is effectively delivered with the change of transmission rate as the distance between the wireless station and its access point increases.

• Journal of Internet Computing and Services
• /
• v.17 no.6
• /
• pp.25-31
• /
• 2016

Recently, with greatly improving the wireless communication technology, new services are created using smart sensors, i.e., machine-to-machine (M2M) and Internet of Things (IoT). In this paper, we propose a novel IoT device (IoTD) personalization method that adopt Small-cell Access Points (SAPs) to control IoTDs using user equipments (UEs), e.g., smart phones and tablet PC, from service users. First, we introduce a system architecture that consists of UE, IoTD, and SAP and propose the IoTD personalization method with two procedures, i.e., IoTD profile registration procedure and IoTD control procedure. Finally, through simulations, we evaluated the system performance of the proposed scheme and it is shown that the proposed scheme outperforms the conventional scheme in terms of the packet delay, packet loss probability, and normalized throughput.

• Proceedings of the KOSOMBE Conference
• /
• v.1991 no.05
• /
• pp.86-88
• /
• 1991

A micro-computer based system has been designed to evaluate the performance of infant incubators. The measurement system used a hybrid of analog electronics for amplification, integration and switches and micro-computer for data storage, data display, and control of relay. This approach has been applied to measure the warm-up time, temperature stability, temperature change due to open/close of door and portholes, and temperature distribution on the mattress. The micro-computer provides on-line access of multi-point temperature data.