The Hindu Business Line : Connecting, with Learning eBay

A rich source of IT research papers is www.cs.princeton.edu, the homepage of Princeton University Computer Science Department. Let's start with Nitin Garg's Postal System Based Digital Network And A Distance Learning, which is among the 2006 crop of `Technical Reports'. Garg proposes a `novel approach' named Postmanet, to turn storage media transported by the postal system into a general-purpose and transparent digital network.

That way, he'd like to extend `pervasive, high-bandwidth, and low-cost connectivity to places such as rural areas in developing countries.'

Garg's 159-page dissertation speaks of `a distance learning system, called the Digital StudyHall (DSH)' to connect resource-starved schools in rural India to well-equipped urban schools so that they may benefit from the better human and content resources available in the urban environments. Interestingly, DSH has been in test-deployment since 2005, in Lucknow.

"It connects StudyHall, a highly regarded school in the city of Lucknow, to two village schools and one school for girls from urban slums," says Garg.

One of the several components of DSH is `Learning eBay' or `Repository' - a site that connects learners and teaching staff across time and space. "It is analogous to how an auction site matches supplies and demands," explains the author. "Volunteers and professionals all over the world may contribute content, monitor remote mediation-based classroom sessions; communicate with each other, other teachers, and students in discussions on various topics such as pedagogy research." Another major component of DSH is EdTV: "a mechanism that uses cheap TVs as `networked thin client displays' to address the `display problem' in village schools: the problem of not having enough computer displays for all students to see clearly."

Heaps, ad hoc formats, and sketches

For the technical-minded, here is a July 2006 paper, Linear Logic, Heap-shape Patterns and Imperative Programming by Limin Jia and David Walker. "One of the most important and enduring problems in programming languages research involves verification of programs that construct, manipulate and dispose of complex heap-allocated data structures.

Any solution to this difficult problem can be used to guarantee memory safety properties and as a foundation for the verification of higher-level program properties," begins the introduction.The program heap, if you'd like to know is "a finite partial map from locations to tuples of integers."

Another paper that the avid should be interested in is PADS/ML: A Functional Data Description Language, by Yitzhak Mandelbaum, Kathleen Fisher, David Walker, Mary Fernandez, and Artem Gleyzer. "Massive amounts of useful data are stored and processed in ad hoc formats for which common tools like parsers, printers, query engines and format converters are not readily available," notes the abstract.

"Ad hoc data sources are ubiquitous, arising in industries as diverse as finance, health care, transportation, and telecommunications as well as in scientific domains, such as computational biology and physics."

To resolve the issue, the authors have developed PADS/ML, which has been `inspired by the type structure of functional programming languages.' Their creation uses "dependent polymorphic recursive data types to describe the syntax and the semantic properties of ad hoc data sources." The language is compact and expressive, avers the paper.

"Content-based similarity search for massive amounts of feature-rich (non-text) data is difficult because such data is noisy and their feature vectors are high dimensional," begins the introductionof yet another recent paper titled Analysis of Filtering for Similarity Search using Sketches by William Josephson, Qin Lv, Zhe Wang, Moses Charikar, and Kai Li.

"Sketches are tiny data structures that can be used to efficiently perform filtering high-dimensional data for similarity search," explain the authors.

"To design real systems with sketching techniques, an important design decision is the choice of sketch size given the targeted dataset size and desired filtering quality." Our experimental results show that the model gives conservative and good prediction for image, audio and 3D shape datasets, assert the authors. Promising!

Privilege-escalation vulnerabilities

"In the Secure Internet Programming laboratory at Princeton University, we have been investigating network security management by using logic programming. We developed a rule-based framework - Multihost, Multistage, Vulnerability Analysis (MulVAL) - to perform end-to-end, automatic analysis of multi-host, multi-stage attacks on a large network where hosts run different operating systems. The tool finds attack paths where the adversary will have to use one or more than one weaknesses (buffer overflows) in multiple software to attack the network."

Thus begins on a sombre note the abstract of Windows Access Control Demystified, by Sudhakar Govindavajhala and Andrew W. Appel.

The authors find that "ordinary professional software developers at commercial software vendors have difficulty in evaluating the consequences of the access-control configurations that they choose for their software and services."

What happens as a consequence? "Commercial software can and does have privilege-escalation vulnerabilities caused by access-control misconfiguration."

As a solution to the problem, the authors propose a logical model of Windows access-control, expressed as inference rules in Datalog, which are directly executable in a Prolog system.

"We have a scanner that reads relevant parts of the Windows registry, file system, and service control manager database on a given host to provide input to our logical model. The model runs, and prints out a list of privilege-escalation vulnerabilities, each one with a trace of how each vulnerability might be exploited."

There's more: "When we run this on a typical Windows installation managed by a careful systems administrator, we find several exploitable user-to-administrator and guest-to-any-user vulnerabilities caused by misconfigurations in the default installation of software from Adobe, AOL, Macromedia, Microsoft and some anonymous vendors."

Alarming.

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