Yoonjoo Kwon

Data mining middleware for wide-area high-performance networks

In this paper, we describe two distributed, data intensive applications that were demonstrated at iGrid 2005 (iGrid Demonstration US 109 and iGrid Demonstration US121). One involves transporting astronomical data from the Sloan Digital Sky Survey (SDSS) and the other involves computing histograms from multiple high-volume data streams. Both rely on newly developed data transport and data mining middleware. Specifically, we describe a new version of the UDT network protocol called Composible-UDT, a file transfer utility based upon UDT called UDT-Gateway, and an application for building histograms on high-volume data flows called BESH (for Best Effort Streaming Histogram). For both demonstrations, we include a summary of the experimental studies performed at iGrid 2005.

A simple dynamic clustering approach to achieve energy efficiency for wireless sensor networks

Purpose – Recent wireless communication and electronics technology has enabled the development of low‐cost, low‐power, and multi‐functional sensor nodes. However, the fact that sensor nodes are severely energy‐constrained has been an issue and many energy‐efficient routing protocols have been proposed to resolve it. Cluster‐based routing protocol is one of them. To achieve longer lifetime, some cluster‐based routing protocols use information on GPS‐based location of each sensor node. However, because of high cost, not all sensor nodes can be GPS‐enabled. The purpose of this paper is to propose a simple dynamic clustering approach to achieve energy efficiency for wireless sensor networks (WSN).Design/methodology/approach – Instead of using location information of each sensor node, this approach utilizes information of remaining energy of each sensor node and changes in the number of cluster head nodes dependent on the number of sensor nodes alive. Performance results are presented and compared with some re...

Two-Tier Call Admission Control to Minimize CBP/CDP in Heterogeneous Wireless Networks

This paper proposes a two-tier call admission control scheme for the efficient use of cellular/WLAN integrated resource. The proposed two-tier call admission control has two separated policies for 3 G cellular network and WLAN. Using the proposed call admission control, the call blocking probability and call dropping probability for voice and data calls are reduced and validated by simulations.

A sophisticated base station centralized simple clustering protocol for sensor networks

In wireless sensor networks, energy efficiency has been a key factor. So far, many energy-efficient routing protocols have been proposed and much attention has been paid to cluster-based routing protocols due to their advantages. However, some cluster-based sensor network routing protocols need location information of the sensor nodes in the network to construct clusters efficiently. Owing to the cost, it is not feasible to know the locations of all sensor nodes in the sensor network. In this paper, we propose a sophisticated base station centralized simple clustering protocol (SBCSP). The proposed protocol utilizes the remaining energy of each sensor node, standard deviation of their energy consumed and the number of cluster heads changed depending on the number of sensor nodes alive in the sensor network. Throughout the performance experiments, we show that SBCSP has better performance than low-energy adaptive clustering hierarchy (LEACH).

Eperfi: Design and Implementation of End-to-End Network Performance Measurement and Diagnosis System for High-Speed Networks

This paper presents the design and implementation result of Eperfi (the end-to-end network performance measurement and diagnosis system) in high-speed networks. Eperfi offers 1)the measuring and diagnosing mechanism to find out the cause of the low data transmission rate from link layer to application layer for all nodes on an end-to-end path, 2)the measuring and diagnosing mechanism to inspect whether a bulk data transfer tool such as SCP, SFTP and RSYNC is the cause of low throughput, 3) the graphical view representing real-time network traffic flow and information based on Weathermap, MRTG and Iperf. By using Eperfi, end-users can not only adjust their system to achieve more fast data transmission but also choose a more efficient data transfer tool to fine-tune their system into high-speed networks. Additionally, a network manager can offer an enhanced network service to an end-user by adjusting efficiently their managed network.

Performance Evaluation of Gigabit Ethernet Interfaces

In high performance computational environments, communication stands out as the major limiting factor to performance. However, high speed network infrastructures are constructed and high speed data transfer protocols, such as BIC TCP and UDT, are capable of transferring the data at the speed of 6~7 Gbps. Despite these circumstances, normal PC users, still have difficulties transferring bulk data in 1 Gbps network. In this paper we try to find out performance limiting factor in end systems. First of all, we investigate the performance effect according to types of NIC and we characterize the current capabilities of PCI, PCI-X and PCI-E Gigabit Ethernet Interfaces and identify requisite components for optimal performance.

Hybridtcp for High Speed Data Transfer

There are many emerging eScience applications. More and more scientists want to collaborate on their investigation with international partners without space limitation by using these applications. Since these applications have to analyze the massive raw data, scientists need to send and receive the data in short time. Most of applications use TCP for data transfer. But TCP was designed under low bandwidth network, therefore, general TCP, Reno TCP, cannot utilize the whole bandwidth of high capacity network. There are several TCP variants to solve TCP problems related to high speed networking. They can be classified into two groups: loss based TCP and delay based TCP. In this paper, the two approaches of TCP variants are compared and a hybrid approach for high speed networking is proposed, which is a synergy of delay-based and loss-based approach.

Performance evaluation of TCP variants to downward vertical handoff

The behavior of a regular TCP is not good to adjust quickly to the new higher available bandwidth of a newly arrived network after a downward vertical handoff In this paper, we compare three TCPs by mathematical and simulation analysis to the downward vertical handoff With mathematical analysis, we compare the link utilization of NewReno TCP, Scalable TCP, and BIC TCP Among them, the performance of BIC TCP shows best, and it gets better than the other two as RTT increases With simulation analysis, we compare the throughput of NewReno TCP and BIC TCP BIC TCP has higher throughput than NewReno TCP, and the performance gain by BIC TCP gets larger with longer RTT BIC TCP shows the best performance to the downward vertical handoff among the three TCPs That is because BIC TCP can increase the congestion window size exponentially to find a new available bandwidth with a connection sustained.

A Hybrid Transport Protocol for High Speed Data Transferring in Long Fat Network

There are many emerging eScience applications. More and more scientists want to collaborate on their investigation with international partners without space limitation by using these applications. Since these applications have to analyze the massive raw data, scientists need to send and receive the data in short time. Most of applications use TCP for data transfer. But TCP was designed under low bandwidth network, therefore, general TCP, for example Reno TCP, cannot utilize the whole bandwidth of high capacity network. There are several TCP variants to solve TCP problems related to high speed networking. They can be classified into two groups: loss based TCP and delay based TCP. In this paper, I will compare two approaches of TCP variants and propose a hybrid approach for high speed networking