search for: diversification

Hello, I am Uppinder Chugh (irc nick: icebyte), a senior year undergraduate student majoring in Computer Science and Engineering at Indian Institute of Technology, Guwahati. I'm interested to work on the idea of adding the functionality of search result diversification to Xapian. After having brief conversations with mentors on IRC, I would like to compile the discussions and further discuss the approach I have in mind for implementing the same. First I'd like to give a brief justification of choosing the proposed method: In the literature [1], diversificati...

...posal for GSoC, looking forward to > contributing further to Xapian. I've posted this in the IRC but didn't > receive any reply, so I'm presuming this must've been missed and thus > posting it here. As proposed, I plan to use ClueWeb09 Category B > dataset for evaluating diversification. A hosted copy is available > (http://lemurproject.org/clueweb09.php/index.php#Services) which may > be accessed but requires a license. The license is free and granted to > an organisation by applying online > (http://lemurproject.org/clueweb09/organization_ > agreement.clueweb09.wo...

...xt. Diversified search is key ways for user satisfaction in absence of explicit knowledge of user intent.Diversified search algorithm tries to find out(estimate) different possible context of user query and tries to pull potential document of all context rather than explicitly assuming a context. Diversification can be done by generating different rank list for different context or adding document from different context in a single rank list. Resources: http://nlp.stanford.edu/IR-book/html/htmledition/ponte-and-crofts-experiments-1.html http://dl.acm.org/citation.cfm?id=291008 http://goo.gl/klqYy http://...

On Sun, Jul 31, 2016 at 12:44:16AM +0100, Olly Betts wrote: > Would a method which swapped two elements of an MSet provide what you > need? That would provide a more generic way to adjust the ranking of > an MSet which for example could be used to implement a diversification > feature or something like SQL "GROUP BY". Isn't the most common use going to be that the client (letor or whatever) knows what documents are in what order, possibly with what new weights? I'd have thought people will end up writing the same boilerplate code if they have only...

...Getting Started Guide", trying the examples and look into the related code sometimes. * I had a look at bite-size projects and good first bugs and spent time with few of them by looking at the related code. I will ask the question/clarification in the corresponding thread. * The project 'Diversification of results' piqued my interest. I read the survey paper. Now I have a basic idea about the multiple approaches. Plan: * I will read the survey paper couple of times to grasp the approaches presented, then read the main papers, evaluate which one is suitable for implementing in Xapian. I comm...

> > > I'd prefer to avoid adding things to the public API that don't get > used by end users. However because LTR is outside the Xapian build > tree, we can't easily give it privileged access to Xapian internals. > Sorry for a delayed response. The way I was thinking of performing reranking with updated weights was to add a class MSetRanker (basically containing a

...n successful with my attempts. I am only able to colour them in repeating sets of 3e.g. sp1=blue, sp.2=red, sp.3=yellow, sp.4=blue, sp5=red, sp6=yellow etc. I am also wondering how to colour the branches or edges as the states transition from one to another over time (i.e. as in the "Analyzing diversification with diversitree" manual by Rich FitzJohn on page 23). Code I've been working with is below: library(diversitree) #loads library tree<-read.tree("tree")#loads tree tree<-chronopl(tree, lambda=1,CV=TRUE) #converts to ultrametric states<-read.delim("states", he...

...n attacker can predict the output of the generator by playing it forward. If an attacker can play the generator forward, then the attacker can reproduce the rest of the executable, including the randomized components that are no longer random to the attacker. Reproducing the executable means that diversification isn't going to work because the attacker can plan around it. For reproducibility, such as for debugging, a pure software generator is a good idea. This also prevents blocking read operations in the generator, slowing down the compiler. Software generators can be optimized for speed. These a...

...and is available on CRAN. >From the 'Description' file of version 0.1: Ape provides functions for reading, and plotting phylogenetic trees in parenthetic format (standard Newick format), analyses of comparative data in a phylogenetic framework, analyses of diversification and macroevolution, computing distances from allelic and nucleotide data, reading nucleotide sequences from GenBank via internet, and several tools such as Mantel's test, computation of minimum spanning tree, or the population parameter theta based on various...

...ite will need to test at least 3 major areas: making sure that RNG results are consistent and deterministic, testing that NOPs are actually inserted and scheduling decisions randomized, and verifying that different seeds result in entirely different binaries with approximately equal amounts of diversifications. Speaking of maintenance, we plan to continue work on this in our lab. We can certainly maintain these features at least for the next year and a half, and possibly longer. > There's a "good news" side to this too. Over lunch I talked with one > of our security guys, and he...

...ct the > output of the generator by playing it forward. If an attacker can play the > generator forward, then the attacker can reproduce the rest of the > executable, including the randomized components that are no longer random > to the attacker. Reproducing the executable means that diversification > isn't going to work because the attacker can plan around it. > > I should think that the choices at each decision point of the randomized code-generation effect would require only a few bits from the output of each run of the RNG, and you can run the RNG again for each decision point...

...here did not seem to be a strong consensus in this discussion about whether diversity is critical, although it appears that existing static analysis tools are insufficient to cover all cases. - Distribution. Distributing large numbers of randomized variants to end-users could be difficult. Prelink diversification was mentioned, which may be a good direction to go with this for the future. However, a basic implementation in LLVM would provide a good starting point for future improvements. This implementation would also provide a useful security measure now for users who are already compiling their own softwa...

Hi Stephen, > Greetings LLVM Devs! > > I am a PhD student in the Secure Systems and Software Lab at UC > Irvine. We have been working on adding randomness into code generation > to create a diverse population of binaries. This diversity prevents > code-reuse attacks such as return-oriented-programming (ROP) by > denying the attacker information about the exact code layout.

...o test at least 3 major areas: making > sure that RNG results are consistent and deterministic, testing that NOPs > are actually inserted and scheduling decisions randomized, and verifying > that different seeds result in entirely different binaries with > approximately equal amounts of diversifications. > I really like the idea of verifying that ROP gadgets work across different variants. Even if it doesn't fit in the regression test suite, it should be set up as an integration test. The other three areas you identified largely fit in the regression suite. Thanks! Speaking of maintenan...

Greetings LLVM Devs! I am a PhD student in the Secure Systems and Software Lab at UC Irvine. We have been working on adding randomness into code generation to create a diverse population of binaries. This diversity prevents code-reuse attacks such as return-oriented-programming (ROP) by denying the attacker information about the exact code layout. ROP has been used is several high-profile recent

...not seem to be a strong consensus in this discussion about whether diversity is critical, although it appears that existing static analysis tools are insufficient to cover all cases. > > - Distribution. Distributing large numbers of randomized variants to end-users could be difficult. Prelink diversification was mentioned, which may be a good direction to go with this for the future. However, a basic implementation in LLVM would provide a good starting point for future improvements. This implementation would also provide a useful security measure now for users who are already compiling their own softwa...

On 26 August 2013 11:39, Stephen Crane <sjcrane at uci.edu> wrote: > Greetings LLVM Devs! > > I am a PhD student in the Secure Systems and Software Lab at UC > Irvine. We have been working on adding randomness into code generation > to create a diverse population of binaries. This diversity prevents > code-reuse attacks such as return-oriented-programming (ROP) by >

On 8/28/13 4:37 PM, Nick Lewycky wrote: > On 26 August 2013 11:39, Stephen Crane <sjcrane at uci.edu > <mailto:sjcrane at uci.edu>> wrote: > > Greetings LLVM Devs! > > I am a PhD student in the Secure Systems and Software Lab at UC > Irvine. We have been working on adding randomness into code generation > to create a diverse population of

Dear OpenSSH developers, I've worked this week on an alternative key exchange mechanism, in reaction to the whole NSA leaks and claims over cryptographic backdoors and/or cracking advances. The key exchange is in my opinion the most critical defense against passive eavesdropping attacks. I believe Curve25519 from DJB can give users a secure alternative to classical Diffie-Hellman (with fixed