• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.19-19
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• 2002

In this paper the authors explore the effect of bandwidth sharing to the utility of the customer for the best-effort Internet services and draw a basis for the pricing principle in Internet Protocol networks. Especially, we investigate the behavior of a customer′s utility in case an arbitrary amount of additional bandwidth is allowed to each customer for the elastic traffic, which is the typical example of the non-real time Internet data traffic. After drawing the utility curve, which will be proved to follow the concave curve, we will apply it to the pricing of Internet traffic. Finally, via numerical experiments, we will illustrate the validity and implication of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.277-284
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• 2002

In this paper the authors explore the effect of bandwidth sharing to the utility of the customer for the best-effort Internet services and draw a basis for the pricing principle in Internet Protocol networks. Especially, we investigate the behavior of a customer's utility in case an arbitrary amount of additional bandwidth is allowed to each customer for the elastic traffic, which is the typical example of the non-real time Internet data traffic. After drawing the utility curve, which will be proved to follow the concave curve, we will apply it to the pricing of Internet traffic. Finally, via numerical experiments, we will illustrate the validity and implication of the proposed method.

• ETRI Journal
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• v.36 no.3
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• pp.502-505
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• 2014

Polarized spectrum sharing (PSS) exploits the spectrum opportunities in a polarized domain. However, when it comes to wideband environments PSS is impaired by the frequency-dependent polarization mode dispersion (PMD); thus, the effective throughput of PSS drops. To combat the PMD effect, this work proposes a cluster-based PSS approach to enable PSS on a narrower frequency span. Simulation results show that the effective throughput of PSS on cluster basis outperforms that of PSS on bandwidth and subcarrier basis.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.292-294
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• 2005

The emerging peer-to-peer (P2P) model has recently gained a significant attention due to its high potential of sharing various resources among networked users. Super-peer unstructured P2P systems have been found very effective by dividing the peers into two layers, super-peer and edge peer. Super peer deal with all Queries instead of edge peers. The existing P2P systems assume all super peers have equal roles and capabilities. However, all super peers don't so that edge peers should select the best super peer in order to handle Queries well. In this paper, we suggest the ISP2P (Intelligent Super-peer based P2P) which allows to select the best super peer to the edge peers. We classify super peers according as the capacity of a edge peer to a super peer. We show that considering the quality of a edge peer to a super peer can improve the performance of the response time and bandwidth.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.10
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• pp.511-520
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• 2007

Decay usage scheduling algorithm gives preference to processes that have consumed little CPU in the recent past. It has been widely-used in time-sharing systems such as UNIX, where CPU-intensive processes and interactive processes are mixed. However, there has been no sound understanding about the mixed effects of decay usage parameters on the service performance. This paper empirically analyzes their effects in terms of the resulting service bandwidth and delay Based on such empirical analysis, we derive the clear meaning of each parameter. Such analysis and understanding provides a basis of controlling decay usage parameters for desirable service provision as required by applications.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.499-509
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• 2010

A plethora of transmission control protocol (TCP) congestion control algorithms have been devoted to achieving the ultimate goal of high link utilization and fair bandwidth sharing in high bandwidth-delay product (HBDP) networks. We present a new insight into the TCP congestion control problem; in particular an end-to-end delay-based approach for an HBDP network. Our main focus is to design an end-to-end mechanism that can achieve the goal without the assistance of any network feedback. Without a router's aid in notifying the network load factor of a bottleneck link, we utilize goodput and throughput values in order to estimate the load factor. The obtained load factor affects the congestion window adjustment. The new protocol, which is called TCP-goodput and throughput (GT), adopts the carefully designed inversely-proportional increase multiplicative decrease window control policy. Our protocol is stable and efficient regardless of the link capacity, the number of flows, and the round-trip delay. Simulation results show that TCP-GT achieves high utilization, good fairness, small standing queue size, and no packet loss in an HBDP environment.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.101-106
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• 2006

Grid computing is an emerging technology that enables global resource sharing. In Korea, the $K^*$Grid provides an extremely powerful research environment to both industries and academia. As part of the $K^*$Grid project, we have constructed, together with the Korea Institute of Science and Technology Information and a number of domestic universities, a supercomputer Grid test bed which connects several types of supercomputers based on the globus toolkit. To achieve efficient networking in this Grid testbed, we propose a novel method of available bandwidth measurement, called Decoupled Capacity measurement with Initial Gap (DCIG), using packet trains. DCIG can improve the network efficiency by selecting the best path among several candidates. Simulation results show that DCIG outperforms previous work in terms of accuracy and the required measurement time. We also define a new XML schema for DCIG request/response based on the schema defined by the Global Grid Forum (GGF) Network Measurement Working Group (NM-WG).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11C
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• pp.1095-1101
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• 2007

For the cognitive radio (CR) systems sharing the spectrum with narrowband primary devices, this paper presents a fractional bandwidth (FBW) mode utilizing a variable portion of the system band to avoid the interference to or from the primary devices. For the method, the preamble and FBW mode detection algorithm are provided to obtain the FBW mode information during the synchronization. Simulation results in wireless regional area network (WRAN) environments reveal that the FBW mode can be detected reliably without any deterioration of the synchronization performance.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1828-1829
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• 2006

In this paper, we propose sliding mode congestion controller for differentiated-services network. Two important issue in differentiated-services architecture are bandwidth guarantee and fair sharing of unsubscribed bandwidth among TCP flows with and without bandwidth reservation. We use tight upper and lower bounds for various settings of differentiated-services parameters using the loss-bounded model. The Sliding mode congestion controller scheme is designed using nonlinear control theory based on a nonlinear model of the network that is generated using fluid flow consideration. The methodology used is general and independent of technology, as for example TCP/IP or ATM. The sliding mode congestion controller methodology has been applied to an TCP network. We use NS-2 simulation to demonstrate that the proposed control methodology achieves the desired behavior of the network, and possesses important attributes. as e.g, stable and robust behavior, high utilization with bounded delay and loss, together with good steady-state and transient behavior.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.45-53
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• 2004

This paper proposes and analyzes a new media access control (MAC) scheduling algorithm, “Interleaved Polling with Deficit Round Robin (IPDRR)” that supports weighted fairness among ONUs in Ethernet Passive Optical Network (PON). The purpose of the proposed IPDRR algerian is not only to eliminate the unused bandwidth of upstream ONU traffic, but also to provide weighted fair sharing of upstream bandwidth among ONUs in Ethernet PON systems. Simulation results show that the IPDRR improves the utilization of upstream channel by removing the unused bandwidth and provides weighted fairness among ONUs, although the IPACT scheduling is unfair according to traffic characteristics.