Topology based packet marking for IP traceback

IP source address spoofing exploits a fundamental weakness in the Internet Protocol. It is exploited in many types of network-based attacks such as session hijacking and Denial of Service (DoS). Ingress and egress filtering is aimed at preventing IP spoofing. Techniques such as History based filtering are being used during DoS attacks to filter out attack packets. Packet marking techniques are being used to trace IP packets to a point that is close as possible to their actual source. Present IP spoofing  countermeasures are hindered by compatibility issues between IPv4 and IPv6, implementation issues and their effectiveness under different types of attacks. We propose a topology based packet marking method that builds on the flexibility of packet marking as an IP trace back method while overcoming most of the shortcomings of present packet marking techniques.

Flexible deterministic packet marking: an IP traceback system to find the real source of attacks

Internet Protocol (IP) traceback is the enabling technology to control Internet crime. In this paper, we present a novel and practical IP traceback system called Flexible Deterministic Packet Marking (FDPM) which provides a defense system with the ability to find out the real sources of attacking packets that traverse through the network. While a number of other traceback schemes exist, FDPM provides innovative features to trace the source of IP packets and can obtain better tracing capability than others. In particular, FDPM adopts a flexible mark length strategy to make it compatible to different network environments; it also adaptively changes its marking rate according to the load of the participating router by a flexible flow-based marking scheme. Evaluations on both simulation and real system implementation demonstrate that FDPM requires a moderately small number of packets to complete the traceback process; add little additional load to routers and can trace a large number of sources in one traceback process with low false positive rates. The built-in overload prevention mechanism makes this system capable of achieving a satisfactory traceback result even when the router is heavily loaded. The motivation of this traceback system is from DDoS defense. It has been used to not only trace DDoS attacking packets but also enhance filtering attacking traffic. It has a wide array of applications for other security systems.

Densities of individually marked migrants away from the marking site to estimate population sizes : a test with three wader populations

Capsule Population estimates based on the mark–resighting method can be a useful alternative to population-wide counts.

Aims To investigate whether the mark–resighting method can be used as an alternative to counts to estimate the size of wader populations.

Methods Individual colour-marking and subsequent resightings allowed accurate estimates of annual survival for three populations of waders, on which basis we could estimate the actual number of marked birds alive. Densities of marked birds were determined on sites away (2000–4300 km) from the ringing locations expecting marked birds to be randomly distributed among non-marked conspecifics. Population sizes are estimated by combining these densities with the number of marked birds alive.

Results We found indications that the distribution of marked birds was indeed random in the locations away from the site of marking. The estimated population size of Red Knot Calidris canutus canutus was in accordance with the most recent estimates based on counts. Our estimate of the Calidris c. islandica population was somewhat lower, and that of the Bar-tailed Godwit Limosa lapponica taymyrensis population was considerably lower than the latest estimates based on counts.

Conclusion Population estimates based on the mark–resighting method can be a useful alternative for, or addition to, population-wide counts, as long as the assumption of random distribution of marked birds at the reading sites is taken into account. We conclude that the Afro-Siberian Bar-tailed Godwit population has recently decreased in size or has been substantially overestimated during the counts.

Marking machinima : a case study in assessing student use of a Web 2.0 technology

The model of learning best suited to the future may be one which sees learning as the process of managing the different kinds of participation an individual might have in complex social systems. Learning capability and engagement is thus dependent on the relationship between an individual identity and social systems. We report on the incorporation of machinima, a Web 2.0 technology, as part of an interdisciplinary and collaborative project where the focus is not on the mastery of the tools or the acquisition of predetermined knowledge, but on the development of learning engagement. We provide the case study of a pilot project involving students across two Arts disciplines collaborating via the game, World of Warcraft, to produce an animated adaptation of one of Geoffrey Chaucer's Canterbury Tales. Their contributions were differently assessed according to the pre-existing requirements of their home disciplines. We argue that the assessment in such projects, in conjunction with innovations and experimentation with Web 2.0 technologies, should shift from an emphasis on product to process. We believe that this has a sound pedagogical and theoretical foundation, and also fits better with the increasingly digitalised, unfixed and interdisciplinary world that students will face on graduation.

Measurement and analysis of pavement marking retroreflectivity

Retroreflective pavement markings enhance road safety by increasing visibility of roadway delineation for road users. In most countries, authorities responsible for road safety do not have performance intervention criteria and standards, and rely on fixed-time interval maintenance programs. This practice is undergoing change via the introduction of mobile retroreflectivity recording units. The focus of this study is to investigate the use of standard mobile retroreflectivity recording units and to analyse the observed retroreflectivity data to evaluate the state of pavement markings under investigation. The centreline pavement marking retrorefl/ectivity data collected by Queensland Department of Main Roads using the ECODYN mobile retroreflectivity recording unit are analysed to determine how the factors such as pavement surface type and traffic environment relate to retroreflectivity performance. It has been found that the mobile retroreflectivity recording unit with in-built processing capabilities can be implemented for identifying the requirements of maintenance programs, as well as to relate the observed retroreflectivity with other factors such as pavement surface type and traffic environment. The observed data indicated that there is a disparity between urban and rural roads of southeast Queensland in terms of centreline pavement marking retroreflectivity qualities. Asphalt surfaces, common in urban environments, were found to have average retroreflectivity over 200 mcd/m2/lux, whereas sprayed seal surfaces, common in rural environments, averaged below 170 mcd/m2/lux. About one-third of the roads used in the analysis fell below the generally accepted minimum threshold of 150 mcd/m2/lux at the time of observation.

Marking time: leading and managing the development of assessment in higher education

This book highlights the University of New South Wales (UNSW) Assessment as Learning Project, a three year process of assessment change in faculty. The UNSW Vice-Chancellor, Professor Frederick Hilmer charged faculties with a learning and teaching agenda to investigate ways to make quality assessment practices more effective and efficient for both staff and students. The examples provided in this edited collection demonstrate exemplary case studies and theoretical perspectives on learning, teaching, and assessment. This book presents leading research in assessment as learning with a focus on changing practices as well as discipline specific practices.

A dynamical deterministic packet marking scheme for DDoS traceback

DDoS attack source traceback is an open and challenging problem. Deterministic packet marking (DPM) is a simple and relatively effective traceback scheme among the available traceback methods. However, the existing DPM schemes inheret a critical drawback of scalability in tracing all possible attack sources, which roots at their static mark encoding and attempt to mark all Internet routers for their traceback purpose. We find that a DDoS attack session usually involves a limited number of attack sources, e.g. at the thousand level. In order to achieve the traceback goal, we only need to mark these attack related routers. We therefore propose a novel Marking on Demand (MOD) scheme based on the DPM mechanism to dynamical distribute marking IDs in both temporal and space dimensions. The proposed MOD scheme can traceback to all possible sources of DDoS attacks, which is not possible for the existing DPM schemes. We thoroughly compare the proposed MOD scheme with two dominant DPM schemes through theoretical analysis and experiments. The the results demonstrate that the MOD scheme outperforms the existing DPM schemes. © 2013 IEEE.

Marking Four Decades of World Heritage - the view from Australia

 The celebration of the milestone of the fortieth year since the adoption by UNESCO of the World Heritage Convention provided a global stimulus for reflection that included activities in Australia. Four decades of experience of implementing the idealistic and international notions that underpin the Convention had demonstrated the distinctiveness of the potential contributions from Australia, New Zealand and the Pacific. With that in mind, the starting premise of this volume of Historic Environment has been to provide a snapshot of the experiences of World Heritage in Australia - essentially the view from 'here', and a specifically oriented view based on the experiences and priorities of cultural heritage practice.

Marking time: duration as subject (Tony Woods)

Tony Woods: Archive, edited by Andrew Gaynor and published locally in 2013, records the durability of the artist’s primary painting practice as will as his filmmkaing, a painting practice in which he has accrued a level of prestige over many years and changes of circumstance.

An assessment of existing bicycle advisory pavement marking on urban roads

Bicycle advisory treatments are used to advise road users of the potential presence of cyclists and of the location where cyclists may be expected to ride on a road. They include pavement markings, warning signs, guide signs, and as such have no regulatory function. The most common type of bicycle advisory pavement markings is the shared lane marking. Other forms of bicycle advisory pavement marking have also been trialled and used in several local jurisdictions. The bicycle awareness zone is an example of such facility which has been trialled and used in southeast Queensland, Australia since the late 1990s. A bicycle awareness zone is similar to shared lane marking in principle but differs in the type of logo and, in some cases, location of its placement on the road. This study assesses the operational and safety issues at three bicycle awareness zone sites by analysing video-assisted observation data collected in 2011 by Queensland Department of Transport and Main Roads, Australia. Of the several applications of bicycle awareness zones, this study only covers a particular application where the centre of the bicycle symbol is placed exactly over the parking edge line. Unlike previous studies, which mostly covered before-and-after evaluations of bicycle advisory pavement markings, the focus of this study is to assess whether the placement of bicycle awareness zone symbols has been successful. The aggregated results from video-assisted observational data show that the cyclists did not always track themselves over the centre of the symbols. Rather, both the cyclists' lateral tracking positions and road user interactions varied with the widths of kerbside parallel parking space. Since the bicycle awareness zone symbols are not positioned on the cyclists' desired line of ride on some roads, their operational effectiveness and safety value are questioned.