Internet Bad Neighborhoods Aggregation

Internet Bad Neighborhoods have proven to be an innovative approach for fighting spam. They have also helped to understand how spammers are distributed on the Internet. In our previous works, the size of each bad neighborhood was fixed to a /24 subnetwork. In this paper, however, we investigate if it is feasible to aggregate Internet bad neighborhoods not only at /24, but to any network prefix. To do that, we propose two different aggregation strategies: fixed prefix and variable prefix. The motivation for doing that is to reduce the number of entries in the bad neighborhood list, thus reducing memory storage requirements for intrusion detection solutions. We also introduce two error measures that allow to quantify how much error was incurred by the aggregation process. An evaluation of both strategies was conducted by analyzing real world data in our aggregation prototype

Evaluating Third-Party Bad Neighborhood Blacklists for Spam Detection

The distribution of malicious hosts over the IP address space is far from being uniform. In fact, malicious hosts tend to be concentrate in certain portions of the IP address space, forming the so-called Bad Neighborhoods. This phenomenon has been previously exploited to filter Spam by means of Bad Neighborhood blacklists. In this paper, we evaluate how much a network administrator can rely upon different Bad Neighborhood blacklists generated by third-party sources to fight Spam. One could expect that Bad Neighborhood blacklists generated from different sources contain, to a varying degree, disjoint sets of entries. Therefore, we investigate (i) how specific a blacklist is to its source, and (ii) whether different blacklists can be interchangeably used to protect a target from Spam. We analyze five Bad Neighborhood blacklists generated from real-world measurements and study their effectiveness in protecting three production mail servers from Spam. Our findings lead to several operational considerations on how a network administrator could best benefit from Bad Neighborhood-based Spam filtering

CommuniSense: Crowdsourcing Road Hazards in Nairobi

Nairobi is one of the fastest growing metropolitan cities and a major business and technology powerhouse in Africa. However, Nairobi currently lacks monitoring technologies to obtain reliable data on traffic and road infrastructure conditions. In this paper, we investigate the use of mobile crowdsourcing as means to gather and document Nairobi's road quality information. We first present the key findings of a city-wide road quality survey about the perception of existing road quality conditions in Nairobi. Based on the survey's findings, we then developed a mobile crowdsourcing application, called CommuniSense, to collect road quality data. The application serves as a tool for users to locate, describe, and photograph road hazards. We tested our application through a two-week field study amongst 30 participants to document various forms of road hazards from different areas in Nairobi. To verify the authenticity of user-contributed reports from our field study, we proposed to use online crowdsourcing using Amazon's Mechanical Turk (MTurk) to verify whether submitted reports indeed depict road hazards. We found 92% of user-submitted reports to match the MTurkers judgements. While our prototype was designed and tested on a specific city, our methodology is applicable to other developing cities.Comment: In Proceedings of 17th International Conference on Human-Computer Interaction with Mobile Devices and Services (MobileHCI 2015

The Median Voter and the Median Consumer: Local Private Goods and Residential Sorting

When a product's product provision entails fixed costs, it will be made available only if a sufficient number of people want it. Some products are produced and consumed locally, so that provision requires not only a large group favoring the product but a large number nearby. Just as one has an incentive to sort into community whose median voter shares his preferences for local public goods, product markets may provide an analogous incentive to sort into a community whose consumers tend to share his preferences in private goods. Using zip code level data on chain restaurants and restaurants overall, this paper documents how the mix of locally available restaurants responds to the local mix of consumers, with three findings. First, based on survey data on chain restaurant patronage, restaurant preferences differ substantially by race and education. Second, there is a strong relationship between restaurants and population at the zip code level, suggesting that restaurants%u2019 geographic markets are small. Finally, the mix of locally available chain restaurants is sensitive to the zipcode demographic mix by race and by education. Hence, differentiated product markets provide a benefit -- proximity to preferred restaurants -- to persons in geographic markets whose customers tend to share their preferences.

The New News: Journalism We Want and Need

Economic pressures on one hand and continuing democratization of news on the other have already changed the news picture in Chicago, as elsewhere in the U.S. The Chicago Tribune and Chicago Sun-Times are in bankruptcy, and local broadcast news programs also face economic pressures. Meanwhile, it seems every week brings a new local news entrepreneur from Gapers Block to Beachwood Reporter to Chi-Town Daily News to Windy Citizen to The Printed Blog.In response to these changes, the Knight Foundation is actively supporting a national effort to explore innovations in how information, especially at the local community level, is collected and disseminated to ensure that people find the information they need to make informed decisions about their community's future. The Chicago Community Trust is fortunate to have been selected as a partner working with the Knight Foundation in this effort through the Knight Community Information Challenge. For 94 years, the Trust has united donors to create charitable resources that respond to the changing needs of our community -- meeting basic needs, enriching lives and encouraging innovative ways to improve our neighborhoods and communities.Understanding how online information and communications are meeting, or not, the needs of the community is crucial to the Trust's project supported by the Knight Foundation. To this end, the Trust commissioned the Community Media Workshop to produce The New News: Journalism We Want and Need. We believe this report is a first of its kind resource offering an inventory and assessment of local news coverage for the region by utilizing the interactive power of the internet. Essays in this report also provide insightful perspectives on the opportunities and challenges

On Compact Routing for the Internet

While there exist compact routing schemes designed for grids, trees, and Internet-like topologies that offer routing tables of sizes that scale logarithmically with the network size, we demonstrate in this paper that in view of recent results in compact routing research, such logarithmic scaling on Internet-like topologies is fundamentally impossible in the presence of topology dynamics or topology-independent (flat) addressing. We use analytic arguments to show that the number of routing control messages per topology change cannot scale better than linearly on Internet-like topologies. We also employ simulations to confirm that logarithmic routing table size scaling gets broken by topology-independent addressing, a cornerstone of popular locator-identifier split proposals aiming at improving routing scaling in the presence of network topology dynamics or host mobility. These pessimistic findings lead us to the conclusion that a fundamental re-examination of assumptions behind routing models and abstractions is needed in order to find a routing architecture that would be able to scale ``indefinitely.''Comment: This is a significantly revised, journal version of cs/050802