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Exhaustion of IPv4 address space is highly aware for most internet players, not only Internet Service Providers (ISPs), but also Telco and Content Providers. A number of IPv4/IPv6 migration/transition tools and mechanisms have been proposed, deployed/implemented world-wide. To make IPv4 networks be able to connect to IPv6 world, 4over6, DS-lite, and 4rd seems to be the most attractive solution according...
This paper presents an annular microstrip antenna with two sectoral slots fed by a coaxial probe on a square vertical ground plane. The proposed microstrip antenna can support the dual-band operation (UHF and microwave RFID bands). From the results, the antenna has the magnitude of S11 less than -10 dB along the bandwidth of 32 MHz (3.51%) for UHF band and 140 MHz (5.76%) for microwave band. The unidirectional...
We propose a cell-based algorithm used to estimate road traffic condition from multiple Global Positioning System (GPS)-equipped taxis. The GPS data is received intermittently at a central server from approximately 4,000 taxis running within Bangkok metropolitan area. The algorithm divides the Bangkok area into 6,400 square cells. Traffic condition considered here is travel time between two cells...
This paper proposes a system for lightweight detection of DoS attacks, called LD2. Our system detects attack activities by observing flow behaviors and matching them with graphlets for each attack type. The proposed system is lightweight because it does not analyze packet content nor packet statistics. We benchmark performance of LD2, in terms of detection accuracy and complexity against Snort, a...
This paper proposes a novel IPv6 address autoconfiguration that works with multiple types of mobile networks, such as MANET, NEMO, MANEMO, as well as regular IPv6 networks. Our proposed algorithm assigns unique addresses to mobile devices without performing duplicate address detection. As a result, an address autoconfiguration can be done rapidly. This is suitable for system that requires dynamic...
In this study, we investigate the method to increase the accuracy of traffic estimation based on multiple GPS data from GPS-equipped vehicles in Bangkok area, Thailand. We propose an algorithm to predict an average speed of a road segment by combining hourly speed profiles of the road with real-time GPS velocity data. The algorithm utilizes incremental weighted update of average travel velocity from...
Due to the expansive use of GPS, GPS data can be used to provide valuable travel time and the travel speed data for the traffic information system. However, to access ID number for personal car would have problems with privacy. Thus, mean travel speed (MTS), which requires individual vehicle tracking, cannot be calculated directly. In this research, we try to estimate the MTS of the road by using...
In mobile IPv6 networks, duplicate address detection (DAD) process is necessary for confirming uniqueness of IPv6 address when mobile node moves to a new network. In standard IPv6 protocol, DAD delay takes at least 1000 ms. It is desirable to reduce DAD delay especially if nodes wish to run real-time applications on the mobile IPv6 networks. This paper proposes fast and robust DAD (FR-DAD) to improve...
In this paper, we study the performance of radio frequency identification (RFID) tags in ultra-high frequency (UHF) band placed in the protective package for animal traceability application. We examine the RFID tag performance by varying the air gap between the tag and the package, both on the top and bottom of the RFID tag. Two types of RFID tag antenna, dipole and meandered dipole antennas, and...
We propose a system that can record driving events and detect unsafe driving behaviors. Three sensors, an engine control unit (ECU) reader, a 3-axis accelerometer, and a camera are used, in which they represent the car, the passenger, and the driverpsilas perspective. Our system combines data from these three sensors with a fuzzy inference system to identify an event of hazardous driving. The output...
Recently, SLAs become an important issue considered in the next generation telecommunication services. The subscriberspsilas perspective drives ISPs eager to support their requirements by offering SLAs across domains. Under deregulatory environment, this paper has adopted a path-classification scheme in order to capture the freedom of policy selection. To prevent selfish path provisioning in the interdomain...
In next generation networks, technological advancements lead a trend towards offering guaranteed services. ISPs are eager to support subscribers' requirements by offering SLAs across domains. This paper considers the interaction between ISPs under deregulatory environment. In order to capture a freedom of the policy selection, path-classification scheme is proposed to group paths into a few choices...
Several components contribute to handover delay of mobile IPv6, namely, movement detection time, address configuration time, binding registration time, and route optimization time. Through testbed experiments, we found that the dominating delay component is the address configuration time, which is the time required to configure a new globally routable IPv6 address on the mobile node after it moves...
Denial of service (DoS) attacks have continued to evolve and impact availability of the Internet infrastructure. Many researchers in the field of network security and system survivability have been developing mechanisms to detect DoS attacks. By doing so they hope to maximize accurate detections (true-positive) and minimize non-justified detections (false-positive). This research proposes a lightweight...
This paper studies the home agent (HA) reliability with TCP. The experiments are performed with two HAs and a backup HA. When the main mobile IPv6 HA fails, the backup HA is used for standby and recovery services instead. The goal of this paper is to minimize the recovery time
This study investigates an alternative way to estimate degrees of road traffic congestion based on routine GPS measurements from main roads in urban areas of Bangkok, Thailand. We classify three levels of traffic congestion according to the weighted exponential moving averages of measured GPS speed. Human perception is used to obtain classification thresholds and evaluated the performance of the proposed...
We investigate issues regarding stability of the GMPLS signaling protocol based on RSVP extensions. We examine possible chains of events that lead to instabilities. We recommend guidelines for GMPLS protocol implementation to ensure protocol stability.
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