Hundreds of studies exist on predator foraging behaviour, and the same holds for anti-predator behaviour in prey. However, despite these many studies, almost nothing is known about diet choice by predators that feed on prey with anti-predator behaviour. We addressed this problem theoretically by incorporating anti-predator vigilance into two classical models of diet choice by predators. Vigilan...

About the P About the P About the P About the P About the Policy Briefs olicy Briefs olicy Briefs olicy Briefs olicy Briefs This year the Crawford School of Economics and Government established an exciting series of Policy Briefs that provide three opinion pieces by researchers on a particular theme or topic. These briefs are designed to provide introductions into key public policy areas that a...

Spam is not only clogging the Internet traffic by consuming a hefty amount of network bandwidth but it is also a source for e-mail born viruses, spyware, adware and Trojan Horses. It is also used to carry out denial of service, directory harvesting and phishing attacks that directly cause financial losses. Further, the contents of spam are often offensive and contain adult oriented and fraudule...

This work presents a symbiotic filtering approach enabling the exchange of relevant word features among different users in order to improve local anti-spam filters. The local spam filtering is based on a ContentBased Filtering strategy, where word frequencies are fed into a Naive Bayes learner. Several Evolutionary Algorithms are explored for feature selection, including the proposed symbiotic ...

This paper presents a content-based approach to spam detection based on low-level information. Instead of the traditional 'bag of words' representation, we use a 'bag of character n-grams' representation which avoids the sparse data problem that arises in n-grams on the word-level. Moreover, it is language-independent and does not require any lemmatizer or 'deep' text preprocessing. Based on ex...

Many Internet Service Providers (ISPs), anti-virus companies, and enterprise email vendors use Domain Name System-based Blackhole Lists (DNSBLs) to keep track of IP addresses that originate spam, so that future emails sent from these IP addresses can be rejected out-of-hand. DNSBL operators populate blocking lists based on complaints from recipients of spam, who report the IP address of the rel...

Michael Dummett’s realism debate is a semantic dispute about the kind of truth conditions had by a given class of sentences. According to his semantic realist, the truth conditions are potentially verification-transcendent in that they may obtain (or not) despite the fact that we may be forever unable to recognize whether they obtain. According to Dummett’s semantic anti-realist, the truth cond...

We provide an automated graph theoretic method for identifying individual users’ trusted networks of friends in cyberspace. We routinely use our social networks to judge the trustworthiness of outsiders, i.e., to decide where to buy our next car, or to find a good mechanic for it. In this work, we show that an email user may similarly use his email network, constructed solely from sender and re...