• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.390-395
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• 1988

The implementation of MAP(Manufacturing Automation Protocol) NIU(network interface uint) is studied and presented in this paper. Hardwares and system softwares for network management, user interface, and medium access control are developed. Also LLC(Logical Link Control) protocol is implemented. Afterwards, The operations of NIU using self-test functions are tested. Compatibility between interfaces according to IEEE 802.4 standard is also tested.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.1
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• pp.99-113
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• 2004

A new architecture called SAN(Storage Area Network) was developed in response to the requirements of high availability of data, scalable growth, and system performance. In order to use SAN more efficiently, most of SAN operating softwares support storage virtualization concepts that allow users to view physical storage devices attached to SAN as a large volume virtually h logical volume manager plays a key role in storage virtualization. It realizes the storage virtualization by mapping logical addresses to physical addresses. A logical volume manager also supports a snapshot that preserves a volume image at certain time and on-line reorganization to allow users to add/remove storage devices to/from SAN even while the system is running. To support the snapshot and the on-line reorganization, most logical volume managers have used table based mapping methods. However, it is very difficult to manage mapping table because the mapping table is large in proportion to a storage capacity. In this paper, we design and implement an efficient and flexible hybrid mapping method based on mathematical equations. The mapping method in this paper supports a snapshot and on-line reorganization. The proposed snapshot and on-line reorganization are performed on the reserved area which is separated from data area of a volume. Due to this strategy normal I/O operations are not affected by snapshot and reorganization. Finally, we show the superiority of our proposed mapping method through various experiments.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.224-232
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• 2004

To guarantee the reliability in multicast transmission, researches providing reliability through hierarchical control tree which is independent on data channel tree are known to provide high scalability. However, the logical control tree in transport layer constructed without topology information of the corresponding network layer tree may inefficiently use the network resources because the logical control tree is not closely related to the tree topology of the network layer. A router assisted control tree mechanism presented in this paper would improve the efficiency of the link as well as it would remove the replicated data. In addition, it requires to a router a small change which examines the message type of the control tree.

• ETRI Journal
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• v.32 no.1
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• pp.11-21
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• 2010

A novel ultra-wideband (UWB) transceiver structure is presented to be used in wireless body area networks (WBANs). In the proposed structure, a data channel and a control channel are combined into a single transmission signal. In the signal, a modulation method mixing pulse position modulation and pulse amplitude modulation is proposed. A mathematical framework calculating the power spectrum density of the proposed pulse-based signal evaluates its coexistence with conventional radio systems. The transceiver structure is discussed, and the receiving performance is investigated in the additive white Gaussian noise channel. It is demonstrated that the proposed scheme is easier to match to the UWB emission mask than conventional UWB systems. The proposed scheme achieves the data rate requirement of WBAN; the logical control channel achieves better receiving performance than the logical data channel, which is useful for controlling and maintaining networks. The proposed scheme is also easy to implement.

• Information and Communications Magazine
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• v.13 no.3
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• pp.61-70
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• 1996

In this paper, the architecture of the LAN Emulation service defined by the ATM Forum is introduced. In order to use the vast base of the existing LAN application software in ATM network. LAN Emulation provides a MAC layer service emulating connectionless services of legacy LANs on ATM networks. LAN Emulation forms a logical overlay network, called and emulated LAN, on top of an ATM network. LAN Emulation service comprises a set of LAN Emulation Clients(LECs) residing in end stations of an emulated LAN and three logical service entities : LAN Emulation Configuration Server (LECS), LAN Emulation Server(LES). and Broadcast and Unknown Server(BUS). LEC utilizes the services provided by these three servers to provide seamless interworking between legacy LANs and ATM networks, and to support transparent communications between LAN applications over ATM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2199-2214
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• 1994

In order to sufficiently utilize the potential effectiveness of ATM networks, systematic and effective network management and control systems must be employed. In addition to network design, planning, and call routing techniques used in traditional circuit-switched networks. ATM networks can provide logical VP(Virtual Path) reconfiguration capabilities which can adapt to changes in the network environment. With a proper application of the VP reconfiguration technique, ATM networks can reduce the overhead of frequent network redesign and the overhead of call routing processing. However, ATM VP reconfiguration is a very complex and difficult problem which consists of many facets of optimization subproblems such as VP routing. VP sizing, VP terminating point location and VC routing. Most previous research on the ATM logical network reconfiguration problem dealt with the subset of the problem. This paper mathematically formulates the ATM network reconfiguration problem completely considering all subproblems. Since it is very difficult to derive the optimal solution of the formulated problem, we develop a heuristic method based on a Max min bandwidth allocation principle. We show the feasibility of the proposed heuristic method with a simple example.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.162-163
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• 2005

One of the most important things in EPON(Ethernet Passive Optical Network) is that ONUs(Optical Network Units) have to share a channel in upstream direction. We proposed a new algorithm of Dynamic Bandwidth Allocation using Multiple LLID(Logical Link IDentifier). We show how to allocate bandwidth in Queues for improving performance from Bandwidth using Multiple LLID.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.345-348
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• 2003

Overlay multicast is proposed as an alternative approach for providing muticast services. A logical infrastructure is built to form an overlay network on top of the physical layer. In this paper, we propose an efficient overlay multicast in wireless ad hoc networks. The overlay multicast tree adapts to the changes in underlying networks. The multicast tree adjusted according to the local member information.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09b
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• pp.122-125
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• 2003

By advent of NNC(Neural Network Chip), it is possible that process in parallel and discern the importance of signal with learning oneself by experience in external signal. So, the design of general purpose operation unit using VHDL(VHSIC Hardware Description Language) on the existing FPGA(Field Programmable Gate Array) can replaced EN(Expert Network) and learning algorithm. Also, neural network operation unit is possible various operation using learning of NN(Neural Network). This paper present general purpose operation unit using hierarchical structure of EN EN of presented structure learn from logical gate which constitute a operation unit, it relocated several layer The overall structure is hierarchical using a module, it has generality more than FPGA operation unit.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.926-929
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• 1988

In this paper, the implementation of NIU (Network Interface Unit) for Token Passing Bus network is studied. The network is based on the IEEE 802.4 standard, which is the basis of MAP. IBM-PC is chosen as host station. The structure of the network and NIU is investigated and the implementation is illustrated. The logical ring constructed following the standard. Transmission and reception of data are tested. The experimental results are referred.