title: Scamper: a scalable and extensible packet prober for active measurement of the internet

authors: Luckie, Matthew John

subjects: computer science

abstract: Path MTU Discovery (PMTUD) is widely believed to be unreliable because of firewalls that discard ICMP “Packet Too Big”messages. This paper measures PMTUD behaviour for 50,000 popular websites and finds the failure rate in IPv4 is much less than previous studies. We measure the overall failure rate between 5% and 18%, depending on the MTU of the constraining link. We explore methods webserver operators are using to reduce their dependence on PMTUD, and find 11% limit themselves to sending packets no larger than 1380 bytes. We identify a number of common behaviours that seem to be software bugs rather than filtering by firewalls. If these are corrected PMTUD failures could be reduced by 63%. We further find the IPv6 failure rate is less than the IPv4 rate even with more scope for failure in IPv6.

text: Scamper: a scalable and extensible packet prober for active measurement of the internet Path MTU Discovery (PMTUD) is widely believed to be unreliable because of firewalls that discard ICMP “Packet Too Big”messages. This paper measures PMTUD behaviour for 50,000 popular websites and finds the failure rate in IPv4 is much less than previous studies. We measure the overall failure rate between 5% and 18%, depending on the MTU of the constraining link. We explore methods webserver operators are using to reduce their dependence on PMTUD, and find 11% limit themselves to sending packets no larger than 1380 bytes. We identify a number of common behaviours that seem to be software bugs rather than filtering by firewalls. If these are corrected PMTUD failures could be reduced by 63%. We further find the IPv6 failure rate is less than the IPv4 rate even with more scope for failure in IPv6.

year: 2010

title: Tag insertion complexity

authors: Yeates, Stuart Andrew

subjects: computer science

abstract: This paper is about inferring markup information, a generalization of part-of-speech-tagging. We use compression models based on a marked-up training corpus and apply them to fresh, unmarked, text. In effect, this technique builds filters that extract information from text in a way that is generalized because it depends on training text rather than preprogrammed heuristics.

text: Tag insertion complexity This paper is about inferring markup information, a generalization of part-of-speech-tagging. We use compression models based on a marked-up training corpus and apply them to fresh, unmarked, text. In effect, this technique builds filters that extract information from text in a way that is generalized because it depends on training text rather than preprogrammed heuristics.

year: 2001

title: Older adult education in a New Zealand university: Developments and issues

authors: Findsen, Brian

abstract: This article explores a case study of educational provision for older adults in the context of continuing education in one of New Zealand’s universities. It explains how developments in older adult education at the University of Waikato have reflected historical and cultural trends related to the wider field of adult and community education (ACE) inside a higher education setting. It discusses issues of tertiary education policy and funding, what constitutes curriculum and provision for older adults and how university-community partnerships have shaped opportunities for both indigenous Māori and Pakeha (European) seniors. Government removal of funding to all universities in New Zealand for ACE at the end of 2012 ended formal provision but older adult education groups, formerly supported by the Centre for Continuing Education in the University of Waikato, have assumed a more proactive stance in planning and implementing their own programmes.

text: Older adult education in a New Zealand university: Developments and issues This article explores a case study of educational provision for older adults in the context of continuing education in one of New Zealand’s universities. It explains how developments in older adult education at the University of Waikato have reflected historical and cultural trends related to the wider field of adult and community education (ACE) inside a higher education setting. It discusses issues of tertiary education policy and funding, what constitutes curriculum and provision for older adults and how university-community partnerships have shaped opportunities for both indigenous Māori and Pakeha (European) seniors. Government removal of funding to all universities in New Zealand for ACE at the end of 2012 ended formal provision but older adult education groups, formerly supported by the Centre for Continuing Education in the University of Waikato, have assumed a more proactive stance in planning and implementing their own programmes.

year: 2014