• Journal of the Korean Data and Information Science Society
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• v.17 no.1
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• pp.13-18
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• 2006

The purpose of this paper is to identify optimal designs of server port connections between two server system for 200-300 user group. Given 3 empirical models as user and port parallel server types under some conditions of 100 Mbps and optimal CPU temperature suggested by Lee and Kim(2005), our results are shown; port parallel model was optimal when traffic processing times measured, and 250 traffics was jumping point as a critical point in our cases.

• Journal of the Korean Institute of Navigation
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• v.21 no.2
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• pp.19-40
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• 1997

When designing new marine traffic routes, it is desirable that the congestion due to traffic volume is evaluated by theoretical traffic capacity or by traffic simulation. Most of these techniques are applied to single server which is not considered channel width. Over-taking or paralle sailing of two or more vessels is allowalbe in Dover, Uraga, Gaduk-sudo, etc under their traffic capacity. In this paper, the Bumper Model is introduced to multiple severs in narrow channel and applied to Uraga Channel in Japan. The minimum width of Uraga Channel is 1, 400 m and its design traffic capacity is evaluated 19.26 ~ 19.52% of the basic traffic capacity. The traffic capacity on Gaduk Channel according to Busan New Port Development in 2011 will be estimated 3.59 % of maximum density and equal to 18.6% of that on Uraga Channel in 1992. The channel width Gaduk-sudo is designed 1, 600~2, 460 m and evaluated safe enough.

• KNOM Review
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• v.21 no.2
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• pp.26-34
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• 2018

With the proliferation of cloud computing and services, the internet traffic and the demand for better quality of service are increasing. For this reason, server virtualization and network virtualization technology, which uses the resources of internal servers in the data center more efficiently, is receiving increased attention. However, the existing hardware Test Access Port (TAP) equipment is unfit for deployment in the virtual datapaths configured for server virtualization. Virtual TAP (vTAP), which is a software version of the hardware TAP, overcomes this problem by duplicating packets in a virtual switch. However, implementation of vTAP in a virtual switch has a performance problem because it shares the computing resources of the host machines with virtual switch and other VMs. We propose a vTAP implementation technique based on the extended Berkeley Packet Filter (eBPF), which is a high-speed packet processing technology, and compare its performance with that of the existing vTAP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1999-2007
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• 2017

In this paper, we implement a multi-band network selection (MNS) system based on Linux operating system which determines the optimal communication link for given network conditions among the available LTE, very high frequency (VHF), and high frequency (HF). The implemented software consists of a network interface, an MNS server, and a user GUI. We perform indoor test to verify the function of the implemented MNS system using two sets of MNS system. To this end, two types of VHF communication links that follow ITU-R M.1842-1 Annex 1 and Annex 4 are emulated in software. In addition, the HF transmission (reception) port of one MNS is directly connected to the HF reception (transmission) port of another MNS. We demonstrate through indoor tests that the implemented MNS system can support seamless maritime communication service in spite of artificial disconnection or re-connection of LTE, VHFs, and HF. The implemented MNS system is applicable to various maritime communication services including e-navigation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.217-220
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• 2005

Internal cities such as gray level been enclosed to building forest are paying a lot of efforts and expenses to change to green city toot park and street tree get put together. By the example, 'GREEN CITY of PUSAN 21' progress to decorate army facilities like the park, and to plant street trees in several places of city plan in Pusan. And urban environment that big citys of advanced nation are agreeable is making in the large park and road street trees at several places in downtown. Because price of tree for the park is very expensive, tree management system was all-important. In this paper, Motes deliver the sensor information in each tree through radio sensor network by server side. This information can use in state grasping of tree, harmful insects courtesy call etc and this system design was suggested to inform to mode of life administration scholars.