• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(3)
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• pp.125-128
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• 2001

Nowadays, Internet users are widespread internationally. Fallowing the users requirements, server has to transfer real-time multimedia data to many clients. Multicast can significantly reduce the system overhead and the network resource waste, so it supports efficient mechanism when server has to transfer same data to many clients. We can deliver multimedia data transfer in real-time using Patching Algorithm which has no delay for service request. And multicast algorithm can support different network bandwidth using Receiver driven Layered Multicast under heterogeneous environment network. The purpose of this paper is to suggest an algorithm that can create new multicast group adequately and transfer real-time multimedia data efficiently under heterogeneous environment.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.221-224
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• 2000

The issue of supporting TCP traffic over ATM networks is currently one of the most important issues in the field of data networks. One important part of this issue is congestion control. In general, congestion control uses method such as packet drop to relieve network resource when the network is congested so as to maintain high throughput and low delay. In addition, congestion control is required to ensure fair sharing of resources among all users during congestion. In this paper we propose a new congestion control method using WRED & per-VC accounting mechanism. This packet discard scheme is proposed with the goal to provide both good performance in terms of throughput and fairness in terms of bandwidth exploitation of the output link among all virtual circuits.

• 전자공학회논문지A
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• 제31A권3호
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• pp.53-67
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• 1994

This paper describes the design of a high-level synthesis system. SODAS-VP. which automatically generates hardwares executing operation sequences in pipelined fashion.Target architecture and clocking schemes to drive pipelined datapath are determined, and the handling of pipeline hazards which degrade the performance of pipeline is considered. Partitioning of an operation into load, operation, and store stages, each of which is executed in partitiones control step, is performend. Pipelinecl hardware is generated by handling pipeline hazards with internal forwarding or delay insertion techniques in partitioning process and resolving resource conflicts among the partitioned control steps with similarity measure as a priority function in module allocation process. Experimental results show that SODAS-VP generates hardwares that execute faster than those generated by HAL and ALPS systems. SODAS-VP brings improvement in execution speed by 17.1% and 7.4% comparing with HAL and ALPS systems for a MCNC benchmark program, 5th order elliptical wave filter,respectively.

• 한국컴퓨터정보학회논문지
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• 제22권2호
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• pp.37-44
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• 2017

Wireless sensor networks are composed of many wireless sensor nodes that are sensing the environments. These networks have many constraints that are resource constraints, wireless communication, self-construction, etc. But they have many applications that are monitoring environment, tracking the object, etc. In this paper, a mechanism of finding QoS Satisfied multi-path is proposed in wireless sensor networks. In order to satisfy the QoS requirement, the proposed mechanism extends the AODV protocol to find multiple paths from a source node to a destination node by using the additional AODV message types that are proposed. This mechanism will be used to support many QoS applications such as minimum delay time, the better reliability and the better throughput by using the QoS satisfied multi-path. Overheads of the proposed mechanism are evaluated using simulation, and it is showed that QoS satisfied multiple paths are found with a little more overhead than the AODV mechanism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권9호
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• pp.4272-4286
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• 2016

In resource constrained sensor networks, usage of efficient routing protocols can have significant impact on energy dissipation. To save energy, we propose an energy efficient routing protocol. In our approach, which integrates clustering and routing in sensor networks, we perform network coding during data routing in order to achieve additional power savings in the cluster head nodes. Efficacy of the proposed method in terms of the throughput and end-to-end delay is demonstrated through simulation results. Significant network lifetime is also achieved as compared with other techniques.

• 제어로봇시스템학회논문지
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• 제7권11호
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• pp.962-966
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• 2001

The major problem at a branch point for point-to-multipoint available bit rate(ABR) services in asynchronous transfer mode (ATM) networks is how to consolidate backward resource management(BRM) cells from each branch for a multicast connection. In this paper, we propose an efficient feedback consolidation algorithm based on an adaptive dynamic threshold(ADT) to eliminate the consolidation noise and the reduce the consolidation delay. The main idea of the ADT algorithm lies in that each branch point estimates the ABR traffic condition of the network through the virtual queue estimation and the transmission threshold of the queue level in branch points is adaptively controlled according to the estimation. Simulation results show that the proposed ADT algorithm can achieve a faster response in congestion status and a higher link utilization compared with the previous works.

• 한국컴퓨터산업학회논문지
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• 제5권9호
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• pp.841-850
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• 2004

본 논문은 분산 시스템하에서 효율적인 분산자원 관리를 위하여, 각 노드는 정확한 의사 결정을 내려야 하는데, 이에 장애가 되는 통신 네트워크상의 지연, 통신 주기, 기타 의사 결정을 위한계산 시간등을 충분히 고려하였다. 또한, 직접 통신 방식을 사용하여 전체 시스템의 성능을 향상시킬 수 있다. 불확실한 부하정보는 시간변화에 따라 부하 정보에 대한 유용성을 변화 시켜 완화하였다.

• 대한안전경영과학회지
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• 제8권6호
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• pp.79-90
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• 2006

Recently the construction of the ERP(Enterprise Resource Planning) system becomes accomplished actively from the many enterprises. But the many problems occur in acquisition of production data which is a fundamental data of system. Also to delay the acquisition of the production result is fatal in the efficient business operation. The construction of the POP(Point of Production) system which acquires production data at real time is become accomplished widely, In the POP system it is most important to acquire the production data which is accurate. But the many enterprises drop the competitive power with acquisition of the data which could not be trusted. In this paper, we analyze these causes and present the method which it can improve the reliability of production data. Also we introduce a real application case.

• Journal of information and communication convergence engineering
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• 제10권1호
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• pp.21-26
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• 2012

As the new requirements for wireless sensor networks are emerging, real-time communications is becoming a major research challenge because resource-constrained sensor nodes are not powerful enough to accommodate the complexity of the protocol. In addition, an efficient energy management scheme has naturally been a concern in wireless sensor networks for a long time. However, the existing schemes are limited to meeting one of these two requirements. To address the two factors together, we propose real-time communications with two approaches, a protocol for satisfied conditions and one for unsatisfied. Under the satisfied requirement, existing real-time protocol is employed. On the other hand, for the unsatisfied requirement, the newly developed scheme replaces the existing scheme by adjusting the transmission range of some surplus nodes. By expanding the transmission range, the end-to-end delay is shortened because the number of intermediate nodes decreases. These nodes conserve their energy for real-time communications by avoiding other activities such as sensing, forwarding, and computing. Finally, simulation results are given to demonstrate the feasibility of the proposed scheme in high traffic environments.

• Journal of Communications and Networks
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• 제12권4호
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• pp.346-357
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• 2010

Opportunistic scheduling provides the capability of resource management in wireless networks by taking advantage of multiuser diversity and by allowing delay variation in delivering data packets. It generally aims to maximize system throughput or guarantee fairness and quality of service (QoS) requirements. In this paper, we develop an extended proportional fair (PF) scheduling policy that can statistically guarantee three kinds of QoS. The scheduling policy is derived by solving the optimization problems in an ideal system according to QoS constraints. We prove that the practical version of the scheduling policy is optimal in opportunistic scheduling systems. As each scheduling policy has some parameters, we also consider practical parameter adaptation algorithms that require low implementation complexity and show their convergences mathematically. Through simulations, we confirm that our proposed schedulers show good fairness performance in addition to guaranteeing each user's QoS requirements.