A report on WPMSIIP’2015, by Christoph Jansen and Julia Plass

The 8th Workshop on Principles and Methods of Statistical Inference with Interval Probability, organized by the working group “Foundations of Statistics and Their Applications” of the Department of Statistics and the “Munich Center for Mathematical Philosophy (MCMP)” of the Department of Philosophy from the LMU Munich took place from the 1st to the 6th of September 2015 (actually we ended at the 5th, because unfortunately our excursion was cancelled because of bad weather forecast…).


In the old WPMSIIP tradition, on every day there were contributions ranging from well-structured presentations to spontaneous discussions of questions. Further, we completed every day with a visit in some nice restaurant (including “Prinz Myshkin”,  Frank’s favourite).

On Tuesday it was Philosophers’ day, who discussed the phenomenon of dilation.
First Seamus Bradley from the MCMP motivated the topic and gave an introduction to “Dilation and the value of information”. Afterwards, Gregory Wheeler and Arthur Paul Pedersen gave some deeper insights by interactively presenting some new ideas from the field. After lunch, it was discussion time. Here, the discussion (which was masterfully moderated by Greg Wheeler and Paul Pedersen) ranged from hot topics like “examples for non-convex sets of probabilities beyond coin-flipping” to more general considerations such as the role of imprecise probabilities in statistics.

On Wednesday, we turned to some more statistical stuff: Imprecise observations. Firstly, Julia Plass gave a presentation on “Statistical modelling under epistemic data imprecision” and discussed some open questions with the audience. Subsequently, Paul Fink introduced us into the art of playing darts: In his talk he proposed a way to generalize the
(illustration of the) NPI model to coarse data by using a dartboard instead of a probability wheel. This was followed by a lively discussion. In the afternoon, Georg “Giorgio” Schollmeyer talked about structural properties of the rounding mapping and some implications for location measures.  To complete the formal part of the day, we heard some new ideas about “MLE-equivalence and Coarse Data in Generalized Linear Models” by Thomas Augustin, who intends (as a main goal) to generalize the concepts of sufficiency to an IP-based treatment of coarse data.

On Thursday, it was Open Topics Day. Paolo Vicig started with a very welcome tutorial talk on “2-coherent and 2-convex Lower Previsions”, which included a detailed version of his ISIPTA ’15 contribution. Afterwards, Thomas Augustin linked to his WPMSIIP 2014 contribution in Ghent by presenting proposals for solutions for questions that arised in the earlier talk. After having solved his “dog problem” (those who were there will know exactly what we’re talking about), Paul Pedersen joined the group after lunch with a spontaneous
presentation about “Strictly coherent choice”. In the end of the day, Christoph Jansen considered some connections between  “Gamma-maximin and least favourable prior
distributions”.

Friday was reserved for Graphical Models. The first talk was jointly given by Barbara Osimani and Roland Poellinger who addressed some applications in the field of “Nesting Causal Models and Evidential Relations”. Again the talk was accompanied by exciting discussions. Next, it was Eva Endres’ turn. Her talk was about “Probabilistic Graphical Models for Statistical Matching” with a focus on discussing some interesting new questions of how to combine (imprecise) probabilistic  graphical models with methods of statistical matching. To round the (academic part of the) day off, Jasper de Bock enthusiastically recalled some concepts of independence for graphical models under the light of sensitivity analysis.

The week ended with a section on Risk and Reliability. Gero Walter presented some open questions from his research on system reliability (revisiting and extending his ISIPTA ’15 contribution) causing some really productive and helpful discussion with the audience. After that there was a joint presentation given by Jasper de Bock, Thomas Krak and Stavros Lopatatzidis. They intensively made use of the blackboard for giving insights to the theory of Imprecise continous time Markov Chains  with a discrete state space, which ranged from theoretical aspects to computational issues. The afternoon was organized by Ulrika Sahlin. The topic of interest was Evidence-based Decision Theory and in particular how to reflect low evidence via imprecision in the result.

Our impression on WPMSIIP 2015: The worky-shoppy ratio was close to (or even larger than) one. A lot of nice presentations were given and interesting ideas were exchangend.
Organizing the workshop was real fun and thus we can only suggest this job to everyone!

If you wish to do so, please contact Frank Coolen.
For general information see also:

http://maths.dur.ac.uk/stats/people/fc/wpmsiip.html

See you there (whereever that will be…)!

About the authors


Christoph Jansen and Julia Plass are PhD students of Thomas Augustin at the Department of Statistics, LMU Munich. Christophs’s research interests include decision making under complex uncertainty and Julia’s research focus is on coarse data, partial identification and survey statistics.

A report on the 9th SIPTA conference on imprecise probabilities, by Serena Doria

The 9th International Symposium on Imprecise Probability: Theories and Applications was held from Monday 20 to Friday 24 July 2015 in the Italian city of Pescara.

This conference was a result of the productive cooperation among the members of the Steering  Committee, formed by Thomas Augustin, Gert de Cooman, Enrique Miranda, Erik Quaeghebeur, Teddy Seidenfeld, and myself.  I wish to thank  the members of the Local Organizing Committee, Attilio Grilli, Mariangela Scorrano and Andrea Di Cencio for their valuable help and the Department of Engineering and Geology of the University G. d’Annunzio for its financial support.

As with previous ISIPTA meetings, there were only plenary sessions in the program. In total, 31 papers were presented by a short talk and a poster, and 17 additional posters were presented to introduce  preliminary ideas and challenging applications for which the research is not yet completed.

The contributions presented  a large number of new results in different  domains: decision making, statistical inference, belief aggregation, artificial intelligence, and stochastic processes, amongst others.

We were pleased to have three eminent invited speakers:

  • Itzhak Gilboa, from Tel Aviv University and HEC Paris, proposed a unified model of inductive reasoning;
  • Peter Williams, from the University of Sussex and BW Mining, reviewed the intellectual background for the development of coherent lower previsions;
  • Massimo Marinacci, from Bocconi University, discussed approaches to model uncertainty in decision problems.

We were also pleased to have two tutorials to highlight specific subdomains of the wide field of imprecise probability:

  • Barbara Vantaggi, from Universitá “La Sapienza” di Roma, gave a  lecture on de Finetti’s work on coherence and its extensions to an imprecise context;
  • Gregory Wheeler, from Ludwig-Maximilians Universität in Munich,  taught us about the philosophical foundations of imprecise probabilities.

During the conference two sets of prizes were awarded: the Best Poster Award, sponsored by Springer and Wiley, and the IJAR Young Researcher Award, granted by the International Journal of Approximate Reasoning.

The winners of the IJAR Young Researcher Award were

Gold Award

  • Jasper De Bock
  • Denis Deratani Mauà

Silver Award

  • Marco de Angelis
  • Hailin Liu

Honorable Mention

  • Georg Schollmeyer

and the Poster Award Laureates were

  1. Gero Walter, Frank P. A. Coolen, Simme Douwe Flapper: System reliability estimation under prior-data conflict
  2. Gero Walter, Christoph Jansen, Thomas Augustin: Updated network analysis of the imprecise probability community based on ISIPTA electronic proceedings
  3. Erik Quaeghebeur, Chris Wesseling, Emma Beauxis-Aussalet, Teresa Piovesan, Tom Sterkenburg: Eliciting sets of acceptable gambles — The CWI World Cup competition (prize declined)
  4. Julia Plass, Thomas Augustin, Marco E. G. V. Cattaneo, Georg Schollmeyer: Statistical modelling under epistemic data imprecision: some results on estimating multinomial distributions and logistic regression for coarse categorical data
  5. Arthur Van Camp, Gert de Cooman, Enrique Miranda, Erik Quaeghebeur: Modelling indifference with choice functions
  6. Julia Plass, Paul Fink, Norbert Schöning, Thomas Augustin: Statistical modelling in surveys without neglecting the undecided: multinomial logistic regression models and imprecise classification trees under ontic data imprecision
  7. Fabio Gagliardi Cozman: Some remarks on sets of lexicographic probabilities and sets of desirable gambles

About the author

Serena Doria is researcher in Probability and Mathematical Statistics at the Department of Engineering and Geology of the University G.d’Annunzio, Chieti-Pescara, Italy. Her research interests are coherent upper conditional previsions, Hausdorff outer measures, Choquet integral, fractal sets.

A report on the 6th SIPTA school on imprecise probabilities

The sixth SIPTA school on imprecise probabilities was held in the beautiful city of Montpellier (France), on July 21-25, 2014.The school was composed of twenty five participants, from no less than ten different coutnries. It was organized by Kevin Loquin from LIRMM in Montpellier, with the collaboration of Olivier Strauss, Erik Quaeghebeur and Enrique Miranda.

The school was held in the beautiful botanic institute, built in the end of the nineteenth century, situated just next to the oldest french botanic garden.

The school started with the usual introduction to imprecise probability models, given by Sébastien Destercke and Enrique Miranda, during which students learned about lower previsions and about drawing convex sets of probabilities. It was   followed by a course on graphical models and algortihms and approximation methods for imprecise probabilities imparted by Cassio de Campos, Alessandro Antonucci and Francesca Mangili, from the IDSIA research institute in Lugano. This was the occasion to show some possible applications of the monday morning theory.

Tuesday afternoon was time to relax, with a guided tour on the Botanic garden in Montpellier for those who wanted to join. This was the occasion to know all about the history of the garden, as well as of some of its plants. The visit to the glass house under the Montpellier sun was also something to remember. After this cultural event, some of the participants took place in a sports session playing football and volleyball, a good occasion to let off some steam. Finally, the gala dinner at the Oceania Hostel was the occasion to enjoy good food and company in a relaxed atmosphere.

Wednesday morning was the occasion for the students to briefly present their on-going work and projects, in order to grab some pieces of advice from the teachers. After this exchange, Matthias Troffaes from Durham University gave a lecture starting with the basics of decision making with imprecise probabilities and finishing with dynamical decision making.

On Thursday, Gert de Cooman from Ghent University and Erik Quaeghebeur from the CWI in the Netherlands discussed how to make inference with coherent lower previsions, and Inés Couso and Didier Dubois presented other imprecise probability models alternative to coherent lower previsions.

Friday was the good time to take some pictures of the participants, and to finish with less theory and more practice. The morning was devoted to applied topics, such as climate change, environmental risk assessments and tomography, while the afternoon was devoted to a revision session where the students could ask additional questions to the speakers. This session was the occasion to give extra explanation, or to re-explain some notions that were only quickly browsed or ill-understood during the week. It was also quite useful to know what could be improved for the next summer school!
The school was sponsored by LIRMM, the University of Montpellier, Labex Numev and the Pôle de Recherche et d’enseignement supérieur Sud de France. More detailed information about the school as well as the materials from the different sessions can be found at the school website.

 

A report on WPMSIIP’2014, by Arthur van Camp and Stavros Lopatatzidis

The 7th edition of the Workshop on Principles and Methods of Statistical Inference with Interval Probability (abbreviated as WPMSIIP in the most pronounceable way), organised by the SYSTeMS Research group of Ghent University, took place in Ghent from 8 until 12 September 2014.

There were 17 participants from 6 countries.

Every morning and afternoon had its own session in which 2 or 3 persons presented something about a specific topic, in order to stir up the debate, allowing for ample time to discuss and work together.

The first session, on Monday morning, was devoted to statistics. The Institut für Statistik group from the Ludwig Maximilians-Universität Munich led the discussion. All three enthusiastic presenters, Gero Walter, Georg Schollmeyer and Julia Plaß, have their roots in LMU.

In the afternoon, the session was about classification. Unfortunately, prof. Lev Utkin could not make it to Ghent, but luckily Frank Coolen and Paul Fink led the debate lively.

The next session, on Tuesday morning, was about choice functions. Also very unfortunately, Paul Pedersen was unable to come to Ghent. Arthur Van Camp stirred up the discussion about choice functions, and Gert de Cooman filled the gap with a presentation about the foundations of parametric predictive inference.

The next session was foundation, in the afternoon. Enrique Miranda enlightened the audience with a technical discussion about independent products on infinite spaces, Marco Cattaneo warned us about consequences of updating with imprecise probability models, and Erik Quaeghebeur puzzled our minds with a philosophical problem called “Sleeping beauty”.

Wednesday morning was reserved for open topics. Thomas Augustin gave a nice overview of the history of statistics with imprecise probabilities, Qianru Ge introduced an application in reliability optimisation, and Vladimir Vovk talked about the invalidity of NPI.

In the afternoon, we all went to the Ghent city brewery Gruut, where they introduced us both theoretically and pratically in the brewing process. After that, we discovered Ghent from another side: from the side of the water. We sailed with two boats along the inner canals of Ghent.

 

 

 

On Thursday morning there was a session about bivariate models and copulas.

Frank Coolen showed us how to use copulas for inference for bivariata data, and Enrique Miranda “crushed” the podium with results on bivariate p-boxes. Both speakers granted us with lots of interesting discussion material.

After that, in the afternoon, we had a session about credal networks. Cedric De Boom presented the work he did for his master’s thesis, and Jasper De Bock saddled us with many challenging questions regarding independence.

The last day started with a session about stochastic processes, where Francesca Mangili discussed with us about Bayesian nonparametric methods for hypothesis testing. The session ended with Stavros Lopatatzidis who introduced imprecise queueing systems, thereby using the public as a real life example.

The last session of this WPMSIIP was about game-theoretic probability. With Vladimir Vovk presenting material on conformal predictions, and Gert de Cooman introducing a new point wise ergodic theorem, we had two very interesting speakers to end the seventh WPMSIIP.

We have the feeling that the workshop provided food for discussion, revealed several aspects of imprecise probabilities in real life—such as the betting framework— and created the opportunity to better know our international colleagues a bit more informally. We were very pleased to organise this workshop, together with Gert and Jasper.

About the authors

Arthur van Camp and Stavros Lopatatzidis are PhD students at SYSTeMS Group within Ghent University. Research Group at Ghent University. Stavros’ research interests include artificial intelligence, and especially probabilistic models, game theory, queueing theory and multi-agent systems. Arthur’s research interests are in choice functions, and imprecise probability theory in general.

A report on the Workshop Imprecise Probabilities in Statistics and Philosophy, by Seamus Bradley

A workshop on Imprecise Probabilities in Statistics and Philosophy took place at LMU Munich on the 27th and 28th of June. The workshop was co-organised by the Munich Center for Mathematical Philosophy and the LMU statistics department. There were speakers from four continents, and a broad range of views in philosophy and statistics were represented. The conference was a great success and we hope that this leads to closer ties between the philosophy and statistics communities.

The conference opened with the first keynote talk by Teddy Seidenfeld who discussed two criteria for coherence of personal probabilities and their extensions to Imprecie Probabilities (IP). Next, Carl Wagner discussed an extension of Jeffrey conditioning to more general kinds of evidence. Frank Coolen then discussed non-parametric predictive inference which naturally gives rise to sets of probabilities. Catrin Campbell-Moore showed how IP arises when attempting to give a semantics for self-referential probabilities.

Brian Hill argued that the standard dynamic choice argument against non-expected utility theories is mistaken. Arthur Paul Pedersen and Gregory Wheeler characterised the conditions under which a set of probabilities is subject to dilation. Frederik Herzberg discussed aggregation of infinitely many probability judgements. The first day of the conference closed with Arthur van Camp building bridges between approaches to rational belief based on desirable sets of gambles and choice functions.

The second keynote speaker, Fabio Cozman, opened day two of IPSP.
He discussed the difficulties with finding a concept of independence for IP that satisfies standard graph-theoretical assumptions. Yann Bennetreau-Dupin pointed out that the problem with “noninformative” (precise) priors being too informative can be overcome with IP and thereby solve paradoxes like the Doomsday paradox. Jan-Willem Romeijn discussed how to develop a theory of when statistical information sanctions full belief. Anthony Peressini used interval analysis applied to imprecise chances to avoid some problems with the discontinuous evolution of chance.

Marco Cattaneo used a measure based on likelihoods to give some content to the “reliability index” in Gärdenfors and Sahlin’s Unreliable Probabilities model. Seamus Bradley argued that two prima facie problems for updating IP aren’t problems once the proper interpretation of IP is used. Namjoong Kim discussed another problem for IP updating. The conference closed with our final keynote speaker, James M. Joyce, who discussed using scoring rules to model an agent’s epistemic values (e.g. an agent’s attitude to epistemic risk).

The workshop was supported by the Alexander von Humboldt Foundation, the LMU Statistics department and the LMU Universitätsgesellschaft.
The keynote talks were filmed and the videos are available online through the media page of the conference website.

About the author

Seamus Bradley is a postdoctoral research fellow at the Munich Center for Mathematical Philosophy at LMU Munich. His research interests are in philosophical theories of rational belief and decision, and philosophy of science. More information can be found at seamusbradley.net

Two New Books on Imprecise Probability Theories, by Matthias C. M. Troffaes [1]

[1] Thanks to Gert and Frank for proofreading this blog post.

 

 

 

 

 

 

 

 

The Books

Recently, two books have been published on imprecise probability theory:

  1. Lower Previsions: a monograph on said subject by myself and Gert de Cooman.
  2. Introduction to Imprecise Probabilities: a collection of contributed chapters on a wide range of topics, edited by Thomas Augustin, Frank Coolen, Gert de Cooman, and myself, with contributions from Joaquín Abellán, Alessandro Antonucci, Cassio P. de Campos, Giorgio Corani, Sébastien Destercke, Didier Dubois, Robert Hable, Filip Hermans, Nathan Huntley, Andrés Masegosa, Enrique Miranda, Serafín Moral, Michael Oberguggenberger, Erik Quaeghebeur, Glenn Shafer, Damjan Skulj, Michael Smithson, Lev Utkin, Gero Walter, Vladimir Vovk, Paolo Vicig, and Marco Zaffalon.

A monumental effort has gone into both publications. Summaries of their content, with tables of contents, can be found on Wiley’s website, linked above (just click on either title). Gert’s blog also replicates part of the preface of the lower previsions book. In this blog post here on the SIPTA site, I thought it would be useful to provide some insight into why these books have come about at all, why their publication is important, reflect back on how we eventually got there, and perhaps on what the next challenges might be.

But before I do that, I would like to express my enormous thanks to everyone who has supported these books, directly or indirectly, foremost my co-author Gert, co-editors Thomas and Frank, and all contributors named above, but also anyone who has helped the books along from the sidelines, our families, and many of our colleagues (in particular Teddy Seidenfeld), whose advice and help through the years have been invaluable.

Lower Previsions

If I want to go back as far as I can, the Lower Previsions book actually started around 2002, about a year after I started my PhD. Of course, initially, we had no clue yet a book was being conceived. It started with Gert giving me a “toy problem”: extend the theory of lower previsions to unbounded random variables. In the process of solving this problem, a report was written documenting various technical results. Unfortunately I no longer have an exact record of these early versions of the report. But in our paper, “Extension of coherent lower previsions to unbounded random variables” submitted to IPMU 2002, reference [3] says: “Gert de Cooman and Matthias Troffaes. Lower previsions for unbounded random variables. Book, in progress.” Apparently we got less ambitious shortly after. In September 2002, in a paper submitted to SPMS 2002, reference [4] says: “Gert de Cooman and Matthias C. M. Troffaes. Lower previsions for unbounded random variables. Tech. report, [...], in progress.” However, the thought of writing a book was certainly there. As it goes, PhDs are full of distractions, which led to neither book nor report ever being published before the end of my PhD in 2005. Most of the material for the report simply ended up in some way as part of my PhD dissertation.

Around the time of my PhD defence, Gert strongly encouraged me to get my PhD out in book form, particularly the results on unbounded random variables. Leaving these results buried inside the PhD would have been a waste indeed. Moreover, we had many good ideas that we still wanted to explore. So, in July 2005, about a month after I arrived in the US for a year of post-doctoral research with Teddy Seidenfeld, I wrote to Gert (in Dutch, here translated to English):

Subject: hello

[...] Anyway, enjoy the vacation! In the mean time I am trying as soon as possible to get the book about unbounded gambles into an acceptable form. [...]

I honestly did not quite think it would take nine more years. :-)

Since 2006, I have been keeping all my files under version control, and it is quite interesting, not to say even confrontational, to look at those early iterations of what was to become the lower previsions book. The earliest LaTeX files I have of the book date from February 22nd 2006: the book was 110 pages long, entitled “Lower previsions for unbounded random quantities”, and Chapters 4 and 5 already contained the core material for what is now in the second part of the book. In May of 2006, at Gert’s suggestion, we made the decision to split the book into two parts: one part based on bounded gambles (the theory initiated by Peter Williams and Peter Walley), and one part on extending the theory to unbounded gambles. This made for a more consistent and self-contained book.

The decision to split the book into two parts also opened up the avenue to discuss a very wide range of new developments in the theory. And so in the next 8 years, various interesting novel results taken from the literature were added as chapters to the first part—not just our own results, but any results that we deemed useful enough for a wide range of people. The first part of Lower Previsions thus became a reference work, giving a wide overview of the key contributions (many, but certainly not all!) to the existing mathematical theory of lower previsions, at least as far as the unconditional theory goes.

One might be tempted to ask whether part one replaces Walley’s 1991 book: it certainly does not. We give a more compact theoretical development of the theory of unconditional lower previsions, and build on that to discuss a wide range of newer developments. Whilst we do discuss some philosophical issues, this is not the focus of the book: Lower Previsions is mathematical monograph. In contrast, Walley’s book goes far deeper into philosophical issues.

Concerning the conditional theory—which we do in the second part when looking at unbounded random variables as well, we depart more clearly from Walley’s approach, instead following Williams’s ideas from the mid 70s. In fact, this also fits the mathematical nature of the work: Williams is not concerned with conglomerability. My personal opinion is that the theory without conglomerability is mathematically much nicer, and in fact, mathematically also more general, as Paolo Vicig always says. Moreover, for constructivists, conglomerability might not be as compelling anyway (this is precisely De Finetti’s objection).

Anyway, we kept adding and adding, and at some point in 2011, it was clear that we simply had to stop doing this if we wanted the book ever to be published. Incomplete chapters were cut, sometimes with pain and sadness. In particular, all reference to gauges were removed. (Gauges provide an elegant abstract way to derive many results quite quickly, however we never managed to introduce them in a way that truly felt right and elegant. Some day I hope to resurrect them.) The next two years were spent on careful reviewing and refining the material—over 400 pages—to perfection.

Introduction to Imprecise Probabilities

Introduction to Imprecise Probabilities, or more briefly, ITIP as we called it pretty much from day one, started in the pub. Frank had this brilliant idea, already for quite a while, that we should spread the imprecise message, and what was obviously missing was a good introductory text on imprecise probability. Yes, there was Walley’s Statistical Reasoning with Imprecise Probabilities, but already in 2009, Walley’s book was getting out of print, with no clear plans for a reprint or second edition despite high demand, essentially due to Peter Walley’s withdrawal from the research community. Yes, Frank knew that Gert and I were working on our book. However, it was also very clear to us that our book would not be appropriate as an introductory book to give to, say, a starting PhD student or interested researcher who is merely looking to have a broad understanding of the field, perhaps looking to apply imprecise probability in some of their research.

So, in Munich, at WPMSIIP 2009, Frank bought everybody a beer, and in a nutshell we all agreed that we would write a chapter. I still fondly recall the intoxicating cheers: “to the book!”. So, everybody got their act together—some authors considerably faster than others—and wrote a chapter.

By 2011, most of the writing was done. During 2012, the chapters were reviewed and revised. In 2013, Thomas and his team in Munich spent a lot of time on making the notation consistent across the entire book, fixing references and various other details. A final revision by the authors ensued, and then essentially the book was submitted.

Lessons Learnt

The experience in getting these two books written and published has been one with great satisfaction at the end, yet some bumps in the road that perhaps could have been avoided.

One bump, common to both books, are the copy-editing and proofing stages conducted with Wiley. For the Lower Previsions book, the copy-edits were provided directly in pdf format, and only after insisting, we were given the edited LaTeX files (actually, word files that contain LaTeX code). Some copy-edits in the pdf however were not marked in the LaTeX code. For ITIP, we simply went with the pdf as it concerned far less material per author and hence not worth the hassle.

This said, I found the Wiley folks very helpful and supportive. Their operations however are not entirely adapted to support very mathematical works, where you want to stick to LaTeX for as long as possible: it is really non-trivial to indicate how, for example, you need a mathematical formula to be fixed. After Wiley’s copy-edits and our corrections to their edits, the end result was probably slightly better.

The main problem was actually punctuation: their copy-editors had a very different way to go about punctuation, and changed commas in every few sentences. It is however very easy to change the meaning of something by changing punctuation. So you really have to be very careful in checking all edits rigorously. Usually they get it right, but too often they do not.

I am unsure as to how one can really avoid these publisher bumps. The LaTeX issue is a matter of communicating clearly your expectations—then still you have to be lucky that these expectations are communicated through to the right person. The copy-editing issue is very hard to avoid: it would be quite unlikely to have a copy-editor well versed in mathematics. Perhaps they could give better guidance on punctuation and other style matters, so the copy-editing is less intrusive.

Another issue is time. How do you actually finish the book in time? This was not as much an issue for ITIP: the scope of the book was well contained and did not change throughout the process. Yes, it was perhaps a bit later than we had foreseen, but not by five years. So, if at all possible, my strong recommendation would be to make sure that indeed the scope is clear and contained, and will remain so. For Lower Previsions, we decided to move direction a few times, sometimes quite drastically, at the expense of time. That said, I think we made the right decisions. Perhaps we could have taken them earlier.

Finally, a lesson learnt from ITIP: how to edit a volume with many contributors? If you want the volume to exhibit consistency, you really need someone to go over the entire thing and make relentless edits. This is not something, say, Wiley’s copy-editor can do, due to the highly specialized field. Frank, Gert, and myself, are eternally grateful to Thomas for having taken this tremendous task upon himself.

About the author


Matthias Troffaes is senior lecturer in statistics at the Department of Mathematical Sciences, Durham
University, UK. His research interests include the foundations of statistics and decision making under severe uncertainty, with applications to engineering, renewable energy, and environment.

Alessandro Antonucci reports on WPMSIIP’2013

The sixth edition of WPMSIIP, the Workshop on Principles and Methods of Statistical Inference with Interval Probability was held in Lugano (Switzerland) between the first and the second week of September 2013. The workshop was a follow-up to previous editions, held in Durham (2008, 2010), Munich (2009, 2012), and Lublijana (2011).

The 2013 edition was organized by the Imprecise Probability Group of IDSIA. About 25 participants from ten different countries attended the workshop. Since its first edition, WPMSIIP is intended as an open forum for researchers interested in interval (and imprecise, thus of great interest for the SIPTA community) probability. Almost all the participants took actively part to the workshop by presenting in their talks ongoing research topics and/or open challenges. Each talk was followed by an open discussion, with no strict time constraints. Yet, despite some very long and intense discussions, the original program was (of course in an imprecise way!) met.

During the first day, the discussion has been focused on classification and regression. Giorgio Corani chaired the classification part: it clearly emerged that the focus of the research on this topic is slightly moving from traditional credal classification to more general (and challenging) data-mining problems like preference learning and multilabel classification. The regression part was chaired by Andrea Wiencierz and the importance of new regression tools to cope with interval data was one of the main output of the discussion. The second day, chaired by Alessio Benavoli and Marco Cattaneo, covered different topics related to learning. An increasing interest for filtering based on interval/imprecise methods was observed, together with the need of novel learning tools for non-parametric imprecise models. Inference was the topic of the third day. Cassio Polpo de Campos chaired the discussion, which was mostly specialized to imprecise probabilistic graphical models. Two major topics were discussed: credal networks with epistemic irrelevance and the application to logic of imprecise models. Decision making and evaluation problems were discussed on the fourth day, chaired by Denis Mauá. The utility-based approach seems a satisfactory answer to the evaluation of imprecise classifiers. The situation is definitely more open for decision making. Finally, on the last day, open problems ranging from very theoretical to very research applied topics were discussed.

Despite such a packed program, it was possible to find time for a hiking excursion in the beautiful Swiss Alps.

 

In summary, the WPMSIIPs meetings should be regarded as an important resource for the SIPTA community. The open format of the workshop allows for exhaustive (and sometimes exhausting!) discussions, something which could hardly be reproduced in other forums. Most of the slides of the talks are available in the workshop website. We look forward to seeing you at WPMSIIP 2014!

The Eighth International Symposium on Imprecise Probabilities: Theories and Applications (ISIPTA ’13)

The Eighth International Symposium on Imprecise Probabilities: Theories and Applications (ISIPTA ’13) took place in the nice city of Compiègne, from July 2nd to July 5th. We have to thank Fabio Cozman, Thierry Denoeux, Teddy Seidenfeld (and myself) for the scientific organization, and Cédric Baudrit, Véronique Berger-Cherfaoui, Thierry Denoeux, Mylène Masson, Benjamin Quost, Mohamed Sallak (and myself) for the local organization. With the participants, they all contributed to make of this ISIPTA a very interesting and friendly meeting.

Pursuing ISIPTA tradition, a total of 38 papers were presented at the conference, each of them with a short talk followed by a poster session. Poster-only contributions were given a one-minute presentation. In addition 4 invited presentations were given: by Alessio Benavoli (“Pushing Dynamic Estimation to the Extremes: from the Moon to Imprecise Probability”), Isaac Elishakoff (“Recent Developments in Applied Mechanics with Uncertainties”), Christophe Labreuche (“Robustness in Multi-Criteria Decision Making and its relation with Imprecise Probabilities”) and Jean-Marc Tallon (“Ambiguity and ambiguity attitudes in economics”).

Before the conference, the first of July was dedicated to tutorials, with Matthias Troffaes introducing imprecise probabilities from an historical perspective, while Thierry Denoeux talked about the basics and latest applications of belief functions. A welcome reception was then given at Saint-Nicolas Room.

On Tuesday evening, all participants gathered in the town hall in which the city representatives welcomed the participants. The speech was followed by a drink well-deserved after a first day of hard work.

 

Thursday had two important events. The first one was the general meeting, in which the new Executive Committee was appointed. The second was the gala dinner at Pierrefond Castle, during which outgoing members (Alessio Benavoli, Frank Coolen and Teddy Seidenfeld) of the Executive Committee were thanked for their hard work for the community, by the means of appropriated gifts (wine, beer, chocolate and books). The dinner was also the occasion to award the winners of the IJAR prize, whose recipients were:

  • Andrea Wiencierz (gold prize)
  • Ignacio Montes Gutiérrez (gold prize)
  • Rocco de Rosa (honorable mention)

The last conference day was Friday, with the closing ceremony ending with the posters awards. The best poster award was given to Erik Quaeghebeur for his poster on “Characterizing Coherence, Correcting Incoherence”. A mention was also given to the posters by:

  • Felipe Aguirre, Christelle Jacob, Sébastien Destercke, Didier Dubois, Mohamed Sallak
  • Arthur Van de Camp, Gert de Cooman
  • Marco Cattaneo
  • Jasper de Bock, Gert de Cooman

We thank all participants, authors, reviewers and organizers for making this ISIPTA a success!

WPMSIIP ’12: Fifth Workshop on Principles and Methods of Statistical Inference with Interval Probability

Gero Walter reports: From September 10th to 15th, the Working Group Methodological Foundations of Statistics and their Applications of the Department of Statistics at LMU Munich hosted the Fifth Workshop on Principles and Methods of Statistical Inference with InteWPMSIIP '12 Group Portraitrval Probability in Munich. During one week, recent research in the field of Imprecise Probability Theory and the potential of imprecise methods to improve statistical analysis was vividly discussed by the workshop’s participants, who included international guests from the UK, France, Russia, Iran, Slovenia, Canada, and Switzerland. An updated programme is available on the workshop’s website.

A brief report on ISIPTA’2011

The 7th International Symposium on Imprecise Probability: Theories and Applications was held in the beautiful city of Innsbruck (Austria), on July 25—28, 2011. It was organized by Frank Coolen, Gert de Cooman, Thomas Fetz and Michael Oberguggenberger, with the help in the local organization of Anna Bombasaro, Bernhard Schmelzer and Reinhard Stix.Hjemmelaget Oppblåsbare telt

A total of 40 papers dealing with theoretical and practical aspects of imprecise probabilities were presented, both in poster and with a short talk.

Moreover, and continuing with the tradition started at the ISIPTA’09 conference in Durham, poster-only presentations were made of papers presenting novel ideas and applications whose research was not yet completed.

On Monday July 25 the ISIPTA General Meeting was held and the new Executive Committee was appointed.

The continuing president, Teddy Seidenfeld, acknowledged the work of the salient members, and particularly of tian xiao chengthe outgoing secretaryUnited States, Erik Quaeghebeur.

A report on that meeting can be found in www.sipta.org.

In addition to the presentations, a special session was devoted on Tuesday 26 to Bruno de Finetti, who was born in Innsbruck in 1906, as a commemoration of the eightieth anniversary of the publication of the famous “De Finetti theorem”. This session had the participation of Fulvia de Finetti, Bruno de Finetti’s daughter, who gave a historical account of Prof. de Finetti’s life; buy essays online uk Paolo Vicig and Teddy Seidenfeld, who discussed Bruno de Finetti’s ideas on imprecision; Gert de Cooman, who presented some results extending De Finetti’s work on exchangeability to the imprecise case; and Reinhard Viertl, who discussed both De Finetti’s relationship with Austria and the connection between his work and fuzzy probability distributionsHüpfburgen .

After the session, the ISIPTA’11 participants gathered at de Finetti’s birthplace were a memorial tablet in his honour was unveiled.Monster Park eau gonflable


Wednesday 27 was also the day of the gala dinner, that took place at the Seegrube restaurant, and where the IJAR Young Researcher Awards were given. The recipients were Bernhard Schmelzer (Gold Award), Rebecca Bakeruk cow belly bouncer, Nathan Hunley, Gero Walter, Richard Crossman and David Sundgren (Silver Award) and Mohamed Boujelben, Jasper de Bock and Gerardo Simari (Honorable Mention).


Finally, on the last day of the conference three interesting tutorials on engineering applications of imprecise probabilities were given by Alberto Bernardinibouncy castle for sale canada, Fulvio Tonon and Michael Oberguggenberger. And, last but not least, during the closing ceremony the Best Poster Award was given to the poster by Manuel Eugster, Gero Walter and Thomas Augustin, entitled A Network Analysis of the Imprecise Probability Community based on ISIPTA Electronic Proceedings with a mention to the posters by:

- Jasper de Bock and Gert de Cooman.

- Erik Quaeghebeur, Gert de Cooman and Filip Hermans.

- Arthur Van Camp, Jasper de Bock, Erik Quaeghebeur, Gert de Cooman and Filip Hermans East Inflatable Rentals.

- Fabio Cuzzolin.

We believe that the ISIPTA’11 conference continued to be the success of the previous conferences, and we would like to thank here both the organizers and the participants for having made this possible through their efforts.