• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1405-1408
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• 2005

An embedded system has been applied to many fields including households and industrial sites. In the past, user interface products with simple functions were commercialized .but now user demands are increasing and the system has more various applicable fields due to a high penetration rate of the Internet. Therefore, the demand for embedded system is tend to rise In this paper, we Implementation of an embedded system for image tracking. This system is used a fixed IP for the reliable server operation on TCP/IP networks. A real time broadcasting of video image on the internet was developed by using an USB camera on the embedded Linux system. The digital camera is connected at the USB host port of the embedded board. all input images from the video camera is continuously stored as a compressed JPEG file in a directory at the Linux web-server. And each frame image data from web camera is compared for measurement of displacement Vector. That used Block matching algorithm and edge detection algorithm for past speed. And the displacement vector is used at pan/tilt motor control through RS232 serial cable. The embedded board utilized the S3C2410 MPU Which used the ARM 920T core form Samsung. The operating system was ported to embedded Linux kernel and mounted of root file system. And the stored images are sent to the client PC through the web browser. It used the network function of Linux and it developed a program with protocol of the TCP/IP.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.265-270
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• 2012

The subscriber access network is cause of the bottleneck phenomenon because equipment and infrastructure were not originally designed for busty high-bandwidth traffic between MAN(Metro Area Network) and LAN(Local Area Network). Whether riding on shorter copper drops or optical fiber, Ethernet is emerging as the future broadband protocol of choice, offering plug and play simplicity, and low cost. EPON(Ethernet Passive Optical Network) combines point-to-multipoint optical infrastructure with low-cost high-bandwidth Ethernet. The future broadband access network will be a combination of point-to-point and point-to-multipoint Ethernet, optimized for transporting IP data, as well as time critical voice and video. EPON is being considered as a novel communications infrastructure for next-generation broadband access network for the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure. But, EPON has a problem with duplex multimedia services. It is the insufficiency of bandwidth for upstream. Because all ONUs use a shared transmission media for upstream. In this paper, we addressed the problem of upstream bandwidth in EPONs. We presented a wavelength division EPON supporting QoS in the differentiated services framework.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.2
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• pp.66-71
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• 2019

In digital pathology, an electronic system in the biomedical domain storage of the files is a big constrain and because all the analysis and annotation takes place at every user-end manually, it becomes even harder to manage the data that is being shared inside an enterprise. Therefore, we need such a storage system which is not only big enough to store all the data but also manage it and making communication of that data much easier without losing its true from. A virtual server setup is one of those techniques which can solve this issue. We set a main server which is the main storage for all the virtual machines(that are being used at user-end) and that main server is controlled through a hypervisor so that if we want to make changes in storage overall or the main server in itself, it could be reached remotely from anywhere by just using the server's IP address. The server in our case includes XML-RPC based API which are transmitted between computers using HTTP protocol. JAVA API connects to HTTP/HTTPS protocol through JAVA Runtime Environment and exists on top of other SDK web services for the productivity boost of the running application. To manage the server easily, we use Tkinter library to develop the GUI and pmw magawidgets library which is also utilized through Tkinter. For managing, monitoring and performing operations on virtual machines, we use Python binding to XML-RPC based API. After all these settings, we approach to make the system user friendly by making GUI of the main server. Using that GUI, user can perform administrative functions like restart, suspend or resume a virtual machine. They can also logon to the slave host of the pool in case of emergency and if needed, they can also filter virtual machine by the host. Network monitoring can be performed on multiple virtual machines at same time in order to detect any loss of network connectivity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2261-2269
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• 2017

The current LTE network system provides service by locally allocating eNodeB to the EPC(Evolved Packet Core). However, it is not suitable for inter-node communication based on the distributed network environment. In this paper, we propose an integrated system by configuring E-UTRAN and EPC as All-In-One type to enable service in each distributed node. M2M UE is mounted on a each node for wireless In-band backhaul link. The integrated node provides inter-node communication over the wireless in-band backhaul link. If a normal UE moves and an access node changes in the system all entities of LTE integrated into one, it is necessary to change the P-GW which is IP anchor. In order to support the inter-node mobility even if P-GW is changed, We defined UPFE(User Packet Forwarding Extension) scheme and implemented the handover procedure of EPC. Also, we analyze the cell range of the integrated LTE system with the addition of the node and compare the handover delay with the current system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.997-1005
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• 2010

Recently, there has been a growing interest in the use of WLAN technology due to its easy deployment, flexibility and so on. Examples of WLAN applications range from standard internet services such as Web access to real-time services with strict latency/throughput requirements such as multimedia video and voice over IP on wireless network environments. Fair and efficient distribution of the traffic loads among APs(Access Points) has become an important issue for improved utilization of WLAN. This paper focuses on an AP selection scheme for achieving better load balance, and hence increasing network resource utilization for each user on wireless network environments. This scheme makes use of active scan patterns and the network delay as main parameters of load measurement and AP selection. This scheme attempts to estimate the AP traffic loads by observing the up/down delay and utilize the results to maximize the link resource efficiency through load balancing. We compared the proposed scheme with the original SNR(Signal to Noise Ratio)-based scheme using the NS-2(Network Simulation.2). We found that the proposed scheme improves the throughput by 12.5% and lower the network up/down link delay by 36.84% and 60.42%, respectively. All in all, the new scheme can significantly increase overall network throughput and reduce up/down delay while providing excellent quality for voice and video services.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.229-235
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• 2019

As the demand for broadband multimedia including the Internet explosively increases, the advancement of the subscriber network is becoming the biggest issue in the telecommunication industry due to the surge of data traffic caused by the emergence of new services such as smart phone, IPTV, VoIP, VOD and cloud services. In this paper, we have developed WDM(Wavelength Division Multiplexing)-PON(passive optical network) based on the 1-Gigabit Reach Externder (RE) technique to reduce optical core. Particularly, in order to strengthen the market competitiveness, we considered low cost, miniaturization, integration technique, and low power of optical parts. In addition, we have developed a batch system by integrating all techniques for reliability, remote management through the development of transmission distance extension and development of capacity increase of optical line by using RE technology in existing PON network. Based on system interworking with existing commercial 1G PON devices, it can be worthy of achievement of wide nationalization and optical core reduction by using this developed system. Based on these results, we are studying development of 10G PON technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4B
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• pp.351-360
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• 2003

All-optical network provede unlimited for bandwidth, the very low bit error rate, and the transparency to IP. Optical networks promise to be the next generation networks that can meet the higher bandwidth demands. However, the number of wavelengths is often not large enough to help a large amount of nodes. The blocking by wavelength contention can be reduced by wavelength conversion, which can't perfectly resolve all situations. Because of that, a lot of groups have proposed unique wavelength assingment algorithms and protocols. Most schemes don't support the priority concepts. This paper describes the unique priority scheme based on the throughput. In this paper, we apply our priority scheme to SWAP(Simple Wavelength Assignment Protocol) and show the performance of the proposed priority scheme. Our proposed priority scheme can be a better solution to solve an important problem about the blocking by wavelength contention into WDM optical networks.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.429-434
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• 2019

There are several high technologies applied to the driving cars such as self-driving car and connected car for safe and convenient driving. VANET provides useful information such as route selection and gas price by communicating nearby cars and RSUs. VANET prefers CCN rather than traditional TCP/IP stack because CCN offers inherent multicast communication for sharing traffic information as well as traditional unicast. When all participating node rebroadcasts the Interest packets in a Vehicular CCN, the network may suffer from Broadcast Storm Problem. In order to mitigate the effect of the problem and to improve the Data packet transmission, not all but some selected nodes have to rebroadcast the packet. This paper simulates car movements using SUMO and evaluates data transmission performance using ns-3. According to the simulation results, when some selected nodes rebroadcast the Interest packets, the transmission performance improves 10% to 25% depending on the number of requesting nodes.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.219-227
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• 2023

The US National Science Foundation's National Ecological Observatory Network (NEON) is a continental-scale program intended to provide open data, samples, and infrastructure to understand changing ecosystems for a period of 30 years. NEON collects co-located measurements of drivers of environmental change and biological responses, using standardized methods at 81 field sites to systematically sample variability and trends to enable inferences at regional to continental scales. Alongside key atmospheric and environmental variables, NEON measures the biodiversity of many taxa, including microbes, plants, and animals, and collects samples from these organisms for long-term archiving and research use. Here we review the composition and use of NEON resources to date as a whole and specific to biodiversity as an exemplar of the potential of national research infrastructure to contribute to globally relevant outcomes. Since NEON initiated full operations in 2019, NEON has produced, on average, 1.4 M records and over 32 TB of data per year across more than 180 data products, with 85 products that include taxonomic or other organismal information relevant to biodiversity science. NEON has also collected and curated more than 503,000 samples and specimens spanning all taxonomic domains of life, with up to 100,000 more to be added annually. Various metrics of use, including web portal visitation, data download and sample use requests, and scientific publications, reveal substantial interest from the global community in NEON. More than 47,000 unique IP addresses from around the world visit NEON's web portals each month, requesting on average 1.8 TB of data, and over 200 researchers have engaged in sample use requests from the NEON Biorepository. Through its many global partnerships, particularly with the Global Biodiversity Information Facility, NEON resources have been used in more than 900 scientific publications to date, with many using biodiversity data and samples. These outcomes demonstrate that the data and samples provided by NEON, situated in a broader network of national research infrastructures, are critical to scientists, conservation practitioners, and policy makers. They enable effective approaches to meeting global targets, such as those captured in the Kunming-Montreal Global Biodiversity Framework.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.592-599
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• 2011

Proxy Mobile IPv6 (PMIPv6) is the network-based mobility management protocol that network supports the mobility of mobile node (MN) on behalf of the MN. In PMIPv6, a multi-homed MN can connect to the PMIPv6 domain by using only one interface even though it has multiple interfaces. It would be efficient when such a multi-homed MN connects to the PMIPv6 domain by using all of its interfaces. If such a multi-homed MN utilizes all of its interfaces, flow mobility can be provided that the MN handovers one or more flows from one interface to another without re-establishing session. In this paper, we propose the flow-based mobility management protocol by considering the intention of the user. The Router Advertisement (RA) message is used in order for the PMIPv6 domain to inform that the MN can utilize the flow mobility. The proposed mechanism is evaluated by analyzing signaling overhead and handover latency, and the numerical results show that the performance is affected by mobility speed of the MN and the failure probability of the wireless link.