@misc{5408,
abstract = {We consider two-player partial-observation stochastic games where player 1 has partial observation and player 2 has perfect observation. The winning condition we study are omega-regular conditions specified as parity objectives. The qualitative analysis problem given a partial-observation stochastic game and a parity objective asks whether there is a strategy to ensure that the objective is satisfied with probability 1 (resp. positive probability). While the qualitative analysis problems are known to be undecidable even for very special cases of parity objectives, they were shown to be decidable in 2EXPTIME under finite-memory strategies. We improve the complexity and show that the qualitative analysis problems for partial-observation stochastic parity games under finite-memory strategies are
EXPTIME-complete; and also establish optimal (exponential) memory bounds for finite-memory strategies required for qualitative analysis. },
author = {Chatterjee, Krishnendu and Doyen, Laurent and Nain, Sumit and Vardi, Moshe},
issn = {2664-1690},
pages = {17},
publisher = {IST Austria},
title = {{The complexity of partial-observation stochastic parity games with finite-memory strategies}},
doi = {10.15479/AT:IST-2013-141-v1-1},
year = {2013},
}
@misc{5409,
abstract = {The edit distance between two (untimed) traces is the minimum cost of a sequence of edit operations (insertion, deletion, or substitution) needed to transform one trace to the other. Edit distances have been extensively studied in the untimed setting, and form the basis for approximate matching of sequences in different domains such as coding theory, parsing, and speech recognition.
In this paper, we lift the study of edit distances from untimed languages to the timed setting. We define an edit distance between timed words which incorporates both the edit distance between the untimed words and the absolute difference in timestamps. Our edit distance between two timed words is computable in polynomial time. Further, we show that the edit distance between a timed word and a timed language generated by a timed automaton, defined as the edit distance between the word and the closest word in the language, is PSPACE-complete. While computing the edit distance between two timed automata is undecidable, we show that the approximate version, where we decide if the edit distance between two timed automata is either less than a given parameter or more than delta away from the parameter, for delta>0, can be solved in exponential space and is EXPSPACE-hard. Our definitions and techniques can be generalized to the setting of hybrid systems, and we show analogous decidability results for rectangular automata.},
author = {Chatterjee, Krishnendu and Ibsen-Jensen, Rasmus and Majumdar, Rupak},
issn = {2664-1690},
pages = {12},
publisher = {IST Austria},
title = {{Edit distance for timed automata}},
doi = {10.15479/AT:IST-2013-144-v1-1},
year = {2013},
}
@misc{5410,
abstract = {Board games, like Tic-Tac-Toe and CONNECT-4, play an important role not only in development of mathematical and logical skills, but also in emotional and social development. In this paper, we address the problem of generating targeted starting positions for such games. This can facilitate new approaches for bringing novice players to mastery, and also leads to discovery of interesting game variants.
Our approach generates starting states of varying hardness levels for player 1 in a two-player board game, given rules of the board game, the desired number of steps required for player 1 to win, and the expertise levels of the two players. Our approach leverages symbolic methods and iterative simulation to efficiently search the extremely large state space. We present experimental results that include discovery of states of varying hardness levels for several simple grid-based board games. Also, the presence of such states for standard game variants like Tic-Tac-Toe on board size 4x4 opens up new games to be played that have not been played for ages since the default start state is heavily biased. },
author = {Ahmed, Umair and Chatterjee, Krishnendu and Gulwani, Sumit},
issn = {2664-1690},
pages = {13},
publisher = {IST Austria},
title = {{Automatic generation of alternative starting positions for traditional board games}},
doi = {10.15479/AT:IST-2013-146-v1-1},
year = {2013},
}
@inbook{5747,
author = {Dragoi, Cezara and Gupta, Ashutosh and Henzinger, Thomas A},
booktitle = {Computer Aided Verification},
isbn = {9783642397981},
issn = {0302-9743},
location = {Saint Petersburg, Russia},
pages = {174--190},
publisher = {Springer Berlin Heidelberg},
title = {{Automatic Linearizability Proofs of Concurrent Objects with Cooperating Updates}},
doi = {10.1007/978-3-642-39799-8_11},
volume = {8044},
year = {2013},
}
@misc{6440,
abstract = {In order to guarantee that each method of a data structure updates the logical state exactly once, al-most all non-blocking implementations employ Compare-And-Swap (CAS) based synchronization. For FIFO queue implementations this translates into concurrent enqueue or dequeue methods competing among themselves to update the same variable, the tail or the head, respectively, leading to high contention and poor scalability. Recent non-blocking queue implementations try to alleviate high contentionby increasing the number of contention points, all the while using CAS-based synchronization. Furthermore, obtaining a wait-free implementation with competition is achieved by additional synchronization which leads to further degradation of performance.In this paper we formalize the notion of competitiveness of a synchronizing statement which can beused as a measure for the scalability of concurrent implementations. We present a new queue implementation, the Speculative Pairing (SP) queue, which, as we show, decreases competitiveness by using Fetch-And-Increment (FAI) instead of CAS. We prove that the SP queue is linearizable and lock-free.We also show that replacing CAS with FAI leads to wait-freedom for dequeue methods without an adverse effect on performance. In fact, our experiments suggest that the SP queue can perform and scale better than the state-of-the-art queue implementations.},
author = {Henzinger, Thomas A and Payer, Hannes and Sezgin, Ali},
issn = {2664-1690},
pages = {23},
publisher = {IST Austria},
title = {{Replacing competition with cooperation to achieve scalable lock-free FIFO queues }},
doi = {10.15479/AT:IST-2013-124-v1-1},
year = {2013},
}
@inproceedings{1374,
abstract = {We study two-player zero-sum games over infinite-state graphs equipped with ωB and finitary conditions. Our first contribution is about the strategy complexity, i.e the memory required for winning strategies: we prove that over general infinite-state graphs, memoryless strategies are sufficient for finitary Büchi, and finite-memory suffices for finitary parity games. We then study pushdown games with boundedness conditions, with two contributions. First we prove a collapse result for pushdown games with ωB-conditions, implying the decidability of solving these games. Second we consider pushdown games with finitary parity along with stack boundedness conditions, and show that solving these games is EXPTIME-complete.},
author = {Chatterjee, Krishnendu and Fijalkow, Nathanaël},
booktitle = {22nd EACSL Annual Conference on Computer Science Logic},
location = {Torino, Italy},
pages = {181 -- 196},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Infinite-state games with finitary conditions}},
doi = {10.4230/LIPIcs.CSL.2013.181},
volume = {23},
year = {2013},
}
@inproceedings{1376,
abstract = {We consider the distributed synthesis problem for temporal logic specifications. Traditionally, the problem has been studied for LTL, and the previous results show that the problem is decidable iff there is no information fork in the architecture. We consider the problem for fragments of LTL and our main results are as follows: (1) We show that the problem is undecidable for architectures with information forks even for the fragment of LTL with temporal operators restricted to next and eventually. (2) For specifications restricted to globally along with non-nested next operators, we establish decidability (in EXPSPACE) for star architectures where the processes receive disjoint inputs, whereas we establish undecidability for architectures containing an information fork-meet structure. (3) Finally, we consider LTL without the next operator, and establish decidability (NEXPTIME-complete) for all architectures for a fragment that consists of a set of safety assumptions, and a set of guarantees where each guarantee is a safety, reachability, or liveness condition.},
author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Otop, Jan and Pavlogiannis, Andreas},
booktitle = {13th International Conference on Formal Methods in Computer-Aided Design},
location = {Portland, OR, United States},
pages = {18 -- 25},
publisher = {IEEE},
title = {{Distributed synthesis for LTL fragments}},
doi = {10.1109/FMCAD.2013.6679386},
year = {2013},
}
@inproceedings{1385,
abstract = {It is often difficult to correctly implement a Boolean controller for a complex system, especially when concurrency is involved. Yet, it may be easy to formally specify a controller. For instance, for a pipelined processor it suffices to state that the visible behavior of the pipelined system should be identical to a non-pipelined reference system (Burch-Dill paradigm). We present a novel procedure to efficiently synthesize multiple Boolean control signals from a specification given as a quantified first-order formula (with a specific quantifier structure). Our approach uses uninterpreted functions to abstract details of the design. We construct an unsatisfiable SMT formula from the given specification. Then, from just one proof of unsatisfiability, we use a variant of Craig interpolation to compute multiple coordinated interpolants that implement the Boolean control signals. Our method avoids iterative learning and back-substitution of the control functions. We applied our approach to synthesize a controller for a simple two-stage pipelined processor, and present first experimental results.},
author = {Hofferek, Georg and Gupta, Ashutosh and Könighofer, Bettina and Jiang, Jie and Bloem, Roderick},
booktitle = {2013 Formal Methods in Computer-Aided Design},
location = {Portland, OR, United States},
pages = {77 -- 84},
publisher = {IEEE},
title = {{Synthesizing multiple boolean functions using interpolation on a single proof}},
doi = {10.1109/FMCAD.2013.6679394},
year = {2013},
}
@inproceedings{1387,
abstract = {Choices made by nondeterministic word automata depend on both the past (the prefix of the word read so far) and the future (the suffix yet to be read). In several applications, most notably synthesis, the future is diverse or unknown, leading to algorithms that are based on deterministic automata. Hoping to retain some of the advantages of nondeterministic automata, researchers have studied restricted classes of nondeterministic automata. Three such classes are nondeterministic automata that are good for trees (GFT; i.e., ones that can be expanded to tree automata accepting the derived tree languages, thus whose choices should satisfy diverse futures), good for games (GFG; i.e., ones whose choices depend only on the past), and determinizable by pruning (DBP; i.e., ones that embody equivalent deterministic automata). The theoretical properties and relative merits of the different classes are still open, having vagueness on whether they really differ from deterministic automata. In particular, while DBP ⊆ GFG ⊆ GFT, it is not known whether every GFT automaton is GFG and whether every GFG automaton is DBP. Also open is the possible succinctness of GFG and GFT automata compared to deterministic automata. We study these problems for ω-regular automata with all common acceptance conditions. We show that GFT=GFG⊃DBP, and describe a determinization construction for GFG automata.},
author = {Boker, Udi and Kuperberg, Denis and Kupferman, Orna and Skrzypczak, Michał},
location = {Riga, Latvia},
number = {PART 2},
pages = {89 -- 100},
publisher = {Springer},
title = {{Nondeterminism in the presence of a diverse or unknown future}},
doi = {10.1007/978-3-642-39212-2_11},
volume = {7966},
year = {2013},
}
@phdthesis{1406,
abstract = {Epithelial spreading is a critical part of various developmental and wound repair processes. Here we use zebrafish epiboly as a model system to study the cellular and molecular mechanisms underlying the spreading of epithelial sheets. During zebrafish epiboly the enveloping cell layer (EVL), a simple squamous epithelium, spreads over the embryo to eventually cover the entire yolk cell by the end of gastrulation. The EVL leading edge is anchored through tight junctions to the yolk syncytial layer (YSL), where directly adjacent to the EVL margin a contractile actomyosin ring is formed that is thought to drive EVL epiboly. The prevalent view in the field was that the contractile ring exerts a pulling force on the EVL margin, which pulls the EVL towards the vegetal pole. However, how this force is generated and how it affects EVL morphology still remains elusive. Moreover, the cellular mechanisms mediating the increase in EVL surface area, while maintaining tissue integrity and function are still unclear. Here we show that the YSL actomyosin ring pulls on the EVL margin by two distinct force-generating mechanisms. One mechanism is based on contraction of the ring around its circumference, as previously proposed. The second mechanism is based on actomyosin retrogade flows, generating force through resistance against the substrate. The latter can function at any epiboly stage even in situations where the contraction-based mechanism is unproductive. Additionally, we demonstrate that during epiboly the EVL is subjected to anisotropic tension, which guides the orientation of EVL cell division along the main axis (animal-vegetal) of tension. The influence of tension in cell division orientation involves cell elongation and requires myosin-2 activity for proper spindle alignment. Strikingly, we reveal that tension-oriented cell divisions release anisotropic tension within the EVL and that in the absence of such divisions, EVL cells undergo ectopic fusions. We conclude that forces applied to the EVL by the action of the YSL actomyosin ring generate a tension anisotropy in the EVL that orients cell divisions, which in turn limit tissue tension increase thereby facilitating tissue spreading.},
author = {Campinho, Pedro},
pages = {123},
publisher = {IST Austria},
title = {{Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading}},
year = {2013},
}
@article{450,
abstract = {Understanding the relative importance of heterosis and outbreeding depression over multiple generations is a key question in evolutionary biology and is essential for identifying appropriate genetic sources for population and ecosystem restoration. Here we use 2455 experimental crosses between 12 population pairs of the rare perennial plant Rutidosis leptorrhynchoides (Asteraceae) to investigate the multi-generational (F1, F2, F3) fitness outcomes of inter-population hybridization. We detected no evidence of outbreeding depression, with inter-population hybrids and backcrosses showing either similar fitness or significant heterosis for fitness components across the three generations. Variation in heterosis among population pairs was best explained by characteristics of the foreign source or home population, and was greatest when the source population was large, with high genetic diversity and low inbreeding, and the home population was small and inbred. Our results indicate that the primary consideration for maximizing progeny fitness following population augmentation or restoration is the use of seed from large, genetically diverse populations.},
author = {Pickup, Melinda and Field, David and Rowell, David and Young, Andrew},
journal = {Proceedings of the Royal Society of London Series B Biological Sciences},
number = {1750},
publisher = {Royal Society, The},
title = {{Source population characteristics affect heterosis following genetic rescue of fragmented plant populations}},
doi = {10.1098/rspb.2012.2058},
volume = {280},
year = {2013},
}
@article{3116,
abstract = {Multithreaded programs coordinate their interaction through synchronization primitives like mutexes and semaphores, which are managed by an OS-provided resource manager. We propose algorithms for the automatic construction of code-aware resource managers for multithreaded embedded applications. Such managers use knowledge about the structure and resource usage (mutex and semaphore usage) of the threads to guarantee deadlock freedom and progress while managing resources in an efficient way. Our algorithms compute managers as winning strategies in certain infinite games, and produce a compact code description of these strategies. We have implemented the algorithms in the tool Cynthesis. Given a multithreaded program in C, the tool produces C code implementing a code-aware resource manager. We show in experiments that Cynthesis produces compact resource managers within a few minutes on a set of embedded benchmarks with up to 6 threads. © 2012 Springer Science+Business Media, LLC.},
author = {Chatterjee, Krishnendu and De Alfaro, Luca and Faella, Marco and Majumdar, Ritankar and Raman, Vishwanath},
journal = {Formal Methods in System Design},
number = {2},
pages = {142 -- 174},
publisher = {Springer},
title = {{Code aware resource management}},
doi = {10.1007/s10703-012-0170-4},
volume = {42},
year = {2013},
}
@article{3261,
abstract = {Cells in a developing embryo have no direct way of "measuring" their physical position. Through a variety of processes, however, the expression levels of multiple genes come to be correlated with position, and these expression levels thus form a code for "positional information." We show how to measure this information, in bits, using the gap genes in the Drosophila embryo as an example. Individual genes carry nearly two bits of information, twice as much as expected if the expression patterns consisted only of on/off domains separated by sharp boundaries. Taken together, four gap genes carry enough information to define a cell's location with an error bar of ~1% along the anterior-posterior axis of the embryo. This precision is nearly enough for each cell to have a unique identity, which is the maximum information the system can use, and is nearly constant along the length of the embryo. We argue that this constancy is a signature of optimality in the transmission of information from primary morphogen inputs to the output of the gap gene network.},
author = {Dubuis, Julien and Tkacik, Gasper and Wieschaus, Eric and Gregor, Thomas and Bialek, William},
journal = {PNAS},
number = {41},
pages = {16301 -- 16308},
publisher = {National Academy of Sciences},
title = {{Positional information, in bits}},
doi = {10.1073/pnas.1315642110},
volume = {110},
year = {2013},
}
@misc{3321,
author = {Quadrianto, Novi and Lampert, Christoph},
booktitle = {Encyclopedia of Systems Biology},
editor = {Dubitzky, Werner and Wolkenhauer, Olaf and Cho, Kwang and Yokota, Hiroki},
pages = {1069 -- 1069},
publisher = {Springer},
title = {{Kernel based learning}},
doi = {10.1007/978-1-4419-9863-7_604},
volume = {3},
year = {2013},
}
@phdthesis{1405,
abstract = {Motivated by the analysis of highly dynamic message-passing systems, i.e. unbounded thread creation, mobility, etc. we present a framework for the analysis of depth-bounded systems. Depth-bounded systems are one of the most expressive known fragment of the π-calculus for which interesting verification problems are still decidable. Even though they are infinite state systems depth-bounded systems are well-structured, thus can be analyzed algorithmically. We give an interpretation of depth-bounded systems as graph-rewriting systems. This gives more flexibility and ease of use to apply depth-bounded systems to other type of systems like shared memory concurrency.
First, we develop an adequate domain of limits for depth-bounded systems, a prerequisite for the effective representation of downward-closed sets. Downward-closed sets are needed by forward saturation-based algorithms to represent potentially infinite sets of states. Then, we present an abstract interpretation framework to compute the covering set of well-structured transition systems. Because, in general, the covering set is not computable, our abstraction over-approximates the actual covering set. Our abstraction captures the essence of acceleration based-algorithms while giving up enough precision to ensure convergence. We have implemented the analysis in the PICASSO tool and show that it is accurate in practice. Finally, we build some further analyses like termination using the covering set as starting point.},
author = {Zufferey, Damien},
pages = {134},
publisher = {IST Austria},
title = {{Analysis of dynamic message passing programs}},
year = {2013},
}
@inproceedings{2847,
abstract = {Depth-Bounded Systems form an expressive class of well-structured transition systems. They can model a wide range of concurrent infinite-state systems including those with dynamic thread creation, dynamically changing communication topology, and complex shared heap structures. We present the first method to automatically prove fair termination of depth-bounded systems. Our method uses a numerical abstraction of the system, which we obtain by systematically augmenting an over-approximation of the system’s reachable states with a finite set of counters. This numerical abstraction can be analyzed with existing termination provers. What makes our approach unique is the way in which it exploits the well-structuredness of the analyzed system. We have implemented our work in a prototype tool and used it to automatically prove liveness properties of complex concurrent systems, including nonblocking algorithms such as Treiber’s stack and several distributed processes. Many of these examples are beyond the scope of termination analyses that are based on traditional counter abstractions.},
author = {Bansal, Kshitij and Koskinen, Eric and Wies, Thomas and Zufferey, Damien},
editor = {Piterman, Nir and Smolka, Scott},
location = {Rome, Italy},
pages = {62 -- 77},
publisher = {Springer},
title = {{Structural Counter Abstraction}},
doi = {10.1007/978-3-642-36742-7_5},
volume = {7795},
year = {2013},
}
@inproceedings{2445,
abstract = {We develop program synthesis techniques that can help programmers fix concurrency-related bugs. We make two new contributions to synthesis for concurrency, the first improving the efficiency of the synthesized code, and the second improving the efficiency of the synthesis procedure itself. The first contribution is to have the synthesis procedure explore a variety of (sequential) semantics-preserving program transformations. Classically, only one such transformation has been considered, namely, the insertion of synchronization primitives (such as locks). Based on common manual bug-fixing techniques used by Linux device-driver developers, we explore additional, more efficient transformations, such as the reordering of independent instructions. The second contribution is to speed up the counterexample-guided removal of concurrency bugs within the synthesis procedure by considering partial-order traces (instead of linear traces) as counterexamples. A partial-order error trace represents a set of linear (interleaved) traces of a concurrent program all of which lead to the same error. By eliminating a partial-order error trace, we eliminate in a single iteration of the synthesis procedure all linearizations of the partial-order trace. We evaluated our techniques on several simplified examples of real concurrency bugs that occurred in Linux device drivers.},
author = {Cerny, Pavol and Henzinger, Thomas A and Radhakrishna, Arjun and Ryzhyk, Leonid and Tarrach, Thorsten},
location = {St. Petersburg, Russia},
pages = {951 -- 967},
publisher = {Springer},
title = {{Efficient synthesis for concurrency by semantics-preserving transformations}},
doi = {10.1007/978-3-642-39799-8_68},
volume = {8044},
year = {2013},
}
@article{2263,
abstract = {Nestin-cre transgenic mice have been widely used to direct recombination to neural stem cells (NSCs) and intermediate neural progenitor cells (NPCs). Here we report that a readily utilized, and the only commercially available, Nestin-cre line is insufficient for directing recombination in early embryonic NSCs and NPCs. Analysis of recombination efficiency in multiple cre-dependent reporters and a genetic mosaic line revealed consistent temporal and spatial patterns of recombination in NSCs and NPCs. For comparison we utilized a knock-in Emx1cre line and found robust recombination in NSCs and NPCs in ventricular and subventricular zones of the cerebral cortices as early as embryonic day 12.5. In addition we found that the rate of Nestin-cre driven recombination only reaches sufficiently high levels in NSCs and NPCs during late embryonic and early postnatal periods. These findings are important when commercially available cre lines are considered for directing recombination to embryonic NSCs and NPCs.},
author = {Liang, Huixuan and Hippenmeyer, Simon and Ghashghaei, H.},
journal = {Biology open},
number = {12},
pages = {1200 -- 1203},
publisher = {The Company of Biologists},
title = {{A Nestin-cre transgenic mouse is insufficient for recombination in early embryonic neural progenitors}},
doi = {10.1242/bio.20122287},
volume = {1},
year = {2012},
}
@article{2302,
abstract = {We introduce propagation models (PMs), a formalism able to express several kinds of equations that describe the behavior of biochemical reaction networks. Furthermore, we introduce the propagation abstract data type (PADT), which separates concerns regarding different numerical algorithms for the transient analysis of biochemical reaction networks from concerns regarding their implementation, thus allowing for portable and efficient solutions. The state of a propagation abstract data type is given by a vector that assigns mass values to a set of nodes, and its (next) operator propagates mass values through this set of nodes. We propose an approximate implementation of the (next) operator, based on threshold abstraction, which propagates only "significant" mass values and thus achieves a compromise between efficiency and accuracy. Finally, we give three use cases for propagation models: the chemical master equation (CME), the reaction rate equation (RRE), and a hybrid method that combines these two equations. These three applications use propagation models in order to propagate probabilities and/or expected values and variances of the model's variables.},
author = {Henzinger, Thomas A and Mateescu, Maria},
journal = {IEEE ACM Transactions on Computational Biology and Bioinformatics},
number = {2},
pages = {310 -- 322},
publisher = {IEEE},
title = {{The propagation approach for computing biochemical reaction networks}},
doi = {10.1109/TCBB.2012.91},
volume = {10},
year = {2012},
}
@article{2318,
abstract = {We show that bosons interacting via pair potentials with negative scattering length form bound states for a suitable number of particles. In other words, the absence of many-particle bound states of any kind implies the non-negativity of the scattering length of the interaction potential. },
author = {Seiringer, Robert},
journal = {Journal of Spectral Theory},
number = {3},
pages = {321--328},
publisher = {European Mathematical Society},
title = {{Absence of bound states implies non-negativity of the scattering length}},
doi = {10.4171/JST/31},
volume = {2},
year = {2012},
}
@article{2411,
abstract = {The kingdom of fungi provides model organisms for biotechnology, cell biology, genetics, and life sciences in general. Only when their phylogenetic relationships are stably resolved, can individual results from fungal research be integrated into a holistic picture of biology. However, and despite recent progress, many deep relationships within the fungi remain unclear. Here, we present the first phylogenomic study of an entire eukaryotic kingdom that uses a consistency criterion to strengthen phylogenetic conclusions. We reason that branches (splits) recovered with independent data and different tree reconstruction methods are likely to reflect true evolutionary relationships. Two complementary phylogenomic data sets based on 99 fungal genomes and 109 fungal expressed sequence tag (EST) sets analyzed with four different tree reconstruction methods shed light from different angles on the fungal tree of life. Eleven additional data sets address specifically the phylogenetic position of Blastocladiomycota, Ustilaginomycotina, and Dothideomycetes, respectively. The combined evidence from the resulting trees supports the deep-level stability of the fungal groups toward a comprehensive natural system of the fungi. In addition, our analysis reveals methodologically interesting aspects. Enrichment for EST encoded data-a common practice in phylogenomic analyses-introduces a strong bias toward slowly evolving and functionally correlated genes. Consequently, the generalization of phylogenomic data sets as collections of randomly selected genes cannot be taken for granted. A thorough characterization of the data to assess possible influences on the tree reconstruction should therefore become a standard in phylogenomic analyses.},
author = {Ebersberger, Ingo and De Matos Simoes, Ricardo and Kupczok, Anne and Gube, Matthias and Kothe, Erika and Voigt, Kerstin and Von Haeseler, Arndt},
journal = {Molecular Biology and Evolution},
number = {5},
pages = {1319 -- 1334},
publisher = {Oxford University Press},
title = {{A consistent phylogenetic backbone for the fungi}},
doi = {10.1093/molbev/msr285},
volume = {29},
year = {2012},
}
@inproceedings{2715,
abstract = {We consider Markov decision processes (MDPs) with specifications given as Büchi (liveness) objectives. We consider the problem of computing the set of almost-sure winning vertices from where the objective can be ensured with probability 1. We study for the first time the average case complexity of the classical algorithm for computing the set of almost-sure winning vertices for MDPs with Büchi objectives. Our contributions are as follows: First, we show that for MDPs with constant out-degree the expected number of iterations is at most logarithmic and the average case running time is linear (as compared to the worst case linear number of iterations and quadratic time complexity). Second, for the average case analysis over all MDPs we show that the expected number of iterations is constant and the average case running time is linear (again as compared to the worst case linear number of iterations and quadratic time complexity). Finally we also show that given that all MDPs are equally likely, the probability that the classical algorithm requires more than constant number of iterations is exponentially small.},
author = {Chatterjee, Krishnendu and Joglekar, Manas and Shah, Nisarg},
location = {Hyderabad, India},
pages = {461 -- 473},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Average case analysis of the classical algorithm for Markov decision processes with Büchi objectives}},
doi = {10.4230/LIPIcs.FSTTCS.2012.461},
volume = {18},
year = {2012},
}
@inproceedings{2825,
abstract = {We study the problem of maximum marginal prediction (MMP) in probabilistic graphical models, a task that occurs, for example, as the Bayes optimal decision rule under a Hamming loss. MMP is typically performed as a two-stage procedure: one estimates each variable's marginal probability and then forms a prediction from the states of maximal probability. In this work we propose a simple yet effective technique for accelerating MMP when inference is sampling-based: instead of the above two-stage procedure we directly estimate the posterior probability of each decision variable. This allows us to identify the point of time when we are sufficiently certain about any individual decision. Whenever this is the case, we dynamically prune the variables we are confident about from the underlying factor graph. Consequently, at any time only samples of variables whose decision is still uncertain need to be created. Experiments in two prototypical scenarios, multi-label classification and image inpainting, show that adaptive sampling can drastically accelerate MMP without sacrificing prediction accuracy.},
author = {Lampert, Christoph},
location = {Lake Tahoe, NV, United States},
pages = {82 -- 90},
publisher = {Neural Information Processing Systems},
title = {{Dynamic pruning of factor graphs for maximum marginal prediction}},
volume = {1},
year = {2012},
}
@article{2848,
abstract = {We study evolutionary game theory in a setting where individuals learn from each other. We extend the traditional approach by assuming that a population contains individuals with different learning abilities. In particular, we explore the situation where individuals have different search spaces, when attempting to learn the strategies of others. The search space of an individual specifies the set of strategies learnable by that individual. The search space is genetically given and does not change under social evolutionary dynamics. We introduce a general framework and study a specific example in the context of direct reciprocity. For this example, we obtain the counter intuitive result that cooperation can only evolve for intermediate benefit-to-cost ratios, while small and large benefit-to-cost ratios favor defection. Our paper is a step toward making a connection between computational learning theory and evolutionary game dynamics.},
author = {Chatterjee, Krishnendu and Zufferey, Damien and Nowak, Martin},
journal = {Journal of Theoretical Biology},
pages = {161 -- 173},
publisher = {Elsevier},
title = {{Evolutionary game dynamics in populations with different learners}},
doi = {10.1016/j.jtbi.2012.02.021},
volume = {301},
year = {2012},
}
@article{2849,
author = {Edelsbrunner, Herbert and Strelkova, Nataliya},
journal = {Russian Mathematical Surveys},
number = {6},
pages = {1167 -- 1168},
publisher = {IOP Publishing Ltd.},
title = {{On the configuration space of Steiner minimal trees}},
doi = {10.1070/RM2012v067n06ABEH004820},
volume = {67},
year = {2012},
}
@inproceedings{2888,
abstract = {Formal verification aims to improve the quality of hardware and software by detecting errors before they do harm. At the basis of formal verification lies the logical notion of correctness, which purports to capture whether or not a circuit or program behaves as desired. We suggest that the boolean partition into correct and incorrect systems falls short of the practical need to assess the behavior of hardware and software in a more nuanced fashion against multiple criteria.},
author = {Henzinger, Thomas A},
booktitle = {Conference proceedings MODELS 2012},
location = {Innsbruck, Austria},
pages = {1 -- 2},
publisher = {Springer},
title = {{Quantitative reactive models}},
doi = {10.1007/978-3-642-33666-9_1},
volume = {7590},
year = {2012},
}
@inproceedings{2890,
abstract = {Systems are often specified using multiple requirements on their behavior. In practice, these requirements can be contradictory. The classical approach to specification, verification, and synthesis demands more detailed specifications that resolve any contradictions in the requirements. These detailed specifications are usually large, cumbersome, and hard to maintain or modify. In contrast, quantitative frameworks allow the formalization of the intuitive idea that what is desired is an implementation that comes "closest" to satisfying the mutually incompatible requirements, according to a measure of fit that can be defined by the requirements engineer. One flexible framework for quantifying how "well" an implementation satisfies a specification is offered by simulation distances that are parameterized by an error model. We introduce this framework, study its properties, and provide an algorithmic solution for the following quantitative synthesis question: given two (or more) behavioral requirements specified by possibly incompatible finite-state machines, and an error model, find the finite-state implementation that minimizes the maximal simulation distance to the given requirements. Furthermore, we generalize the framework to handle infinite alphabets (for example, realvalued domains). We also demonstrate how quantitative specifications based on simulation distances might lead to smaller and easier to modify specifications. Finally, we illustrate our approach using case studies on error correcting codes and scheduler synthesis.},
author = {Cerny, Pavol and Gopi, Sivakanth and Henzinger, Thomas A and Radhakrishna, Arjun and Totla, Nishant},
booktitle = {Proceedings of the tenth ACM international conference on Embedded software},
location = {Tampere, Finland},
pages = {53 -- 62},
publisher = {ACM},
title = {{Synthesis from incompatible specifications}},
doi = {10.1145/2380356.2380371},
year = {2012},
}
@inproceedings{2891,
abstract = {Quantitative automata are nondeterministic finite automata with edge weights. They value a
run by some function from the sequence of visited weights to the reals, and value a word by its
minimal/maximal run. They generalize boolean automata, and have gained much attention in
recent years. Unfortunately, important automaton classes, such as sum, discounted-sum, and
limit-average automata, cannot be determinized. Yet, the quantitative setting provides the potential
of approximate determinization. We define approximate determinization with respect to
a distance function, and investigate this potential.
We show that sum automata cannot be determinized approximately with respect to any
distance function. However, restricting to nonnegative weights allows for approximate determinization
with respect to some distance functions.
Discounted-sum automata allow for approximate determinization, as the influence of a word’s
suffix is decaying. However, the naive approach, of unfolding the automaton computations up
to a sufficient level, is shown to be doubly exponential in the discount factor. We provide an
alternative construction that is singly exponential in the discount factor, in the precision, and
in the number of states. We prove matching lower bounds, showing exponential dependency on
each of these three parameters.
Average and limit-average automata are shown to prohibit approximate determinization with
respect to any distance function, and this is the case even for two weights, 0 and 1.},
author = {Boker, Udi and Henzinger, Thomas A},
booktitle = {Leibniz International Proceedings in Informatics},
location = {Hyderabad, India},
pages = {362 -- 373},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Approximate determinization of quantitative automata}},
doi = {10.4230/LIPIcs.FSTTCS.2012.362},
volume = {18},
year = {2012},
}
@article{2902,
abstract = {We present an algorithm for simplifying linear cartographic objects and results obtained with a computer program implementing this algorithm. },
author = {Edelsbrunner, Herbert and Musin, Oleg and Ukhalov, Alexey and Yakimova, Olga and Alexeev, Vladislav and Bogaevskaya, Victoriya and Gorohov, Andrey and Preobrazhenskaya, Margarita},
journal = {Modeling and Analysis of Information Systems},
number = {6},
pages = {152 -- 160},
publisher = {Technische Universität Darmstadt},
title = {{Fractal and computational geometry for generalizing cartographic objects}},
volume = {19},
year = {2012},
}
@inproceedings{2903,
abstract = {In order to enjoy a digital version of the Jordan Curve Theorem, it is common to use the closed topology for the foreground and the open topology for the background of a 2-dimensional binary image. In this paper, we introduce a single topology that enjoys this theorem for all thresholds decomposing a real-valued image into foreground and background. This topology is easy to construct and it generalizes to n-dimensional images.},
author = {Edelsbrunner, Herbert and Symonova, Olga},
location = {New Brunswick, NJ, USA },
pages = {41 -- 48},
publisher = {IEEE},
title = {{The adaptive topology of a digital image}},
doi = {10.1109/ISVD.2012.11},
year = {2012},
}
@article{2904,
abstract = {Generalized van der Corput sequences are onedimensional, infinite sequences in the unit interval. They are generated from permutations in integer base b and are the building blocks of the multi-dimensional Halton sequences. Motivated by recent progress of Atanassov on the uniform distribution behavior of Halton sequences, we study, among others, permutations of the form P(i) = ai (mod b) for coprime integers a and b. We show that multipliers a that either divide b - 1 or b + 1 generate van der Corput sequences with weak distribution properties. We give explicit lower bounds for the asymptotic distribution behavior of these sequences and relate them to sequences generated from the identity permutation in smaller bases, which are, due to Faure, the weakest distributed generalized van der Corput sequences.},
author = {Pausinger, Florian},
issn = {2118-8572},
journal = {Journal de Theorie des Nombres des Bordeaux},
number = {3},
pages = {729 -- 749},
publisher = {Universite de Bordeaux},
title = {{Weak multipliers for generalized van der Corput sequences}},
doi = {10.5802/jtnb.819},
volume = {24},
year = {2012},
}
@article{2912,
author = {Edelsbrunner, Herbert and Strelkova, Nataliya},
journal = { Uspekhi Mat. Nauk},
number = {6},
pages = {203 -- 204},
publisher = {Moscow Mathematical Society },
title = {{Configuration space for shortest networks }},
doi = {10.4213/rm9503},
volume = {67},
year = {2012},
}
@inproceedings{2915,
author = {Kroemer, Oliver and Lampert, Christoph and Peters, Jan},
publisher = {Deutsches Zentrum für Luft und Raumfahrt},
title = {{Multi-modal learning for dynamic tactile sensing}},
year = {2012},
}
@inproceedings{2916,
abstract = {The classical (boolean) notion of refinement for behavioral interfaces of system components is the alternating refinement preorder. In this paper, we define a quantitative measure for interfaces, called interface simulation distance. It makes the alternating refinement preorder quantitative by, intu- itively, tolerating errors (while counting them) in the alternating simulation game. We show that the interface simulation distance satisfies the triangle inequality, that the distance between two interfaces does not increase under parallel composition with a third interface, and that the distance between two interfaces can be bounded from above and below by distances between abstractions of the two interfaces. We illustrate the framework, and the properties of the distances under composition of interfaces, with two case studies.},
author = {Cerny, Pavol and Chmelik, Martin and Henzinger, Thomas A and Radhakrishna, Arjun},
booktitle = {Electronic Proceedings in Theoretical Computer Science},
location = {Napoli, Italy},
pages = {29 -- 42},
publisher = {EPTCS},
title = {{Interface Simulation Distances}},
doi = {10.4204/EPTCS.96.3},
volume = {96},
year = {2012},
}
@article{2917,
abstract = {The search for extra-terrestrial intelligence (SETI) has been performed principally as a one-way survey, listening of radio frequencies across the Milky Way and other galaxies. However, scientists have engaged in an active messaging only rarely. This suggests the simple rationale that if other civilizations exist and take a similar approach to ours, namely listening but not broadcasting, the result is a silent universe. A simple game theoretical model, the prisoner's dilemma, explains this situation: each player (civilization) can passively search (defect), or actively search and broadcast (cooperate). In order to maximize the payoff (or, equivalently, minimize the risks) the best strategy is not to broadcast. In fact, the active search has been opposed on the basis that it might be dangerous to expose ourselves. However, most of these ideas have not been based on objective arguments, and ignore accounting of the possible gains and losses. Thus, the question stands: should we perform an active search? I develop a game-theoretical framework where civilizations can be of different types, and explicitly apply it to a situation where societies are either interested in establishing a two-way communication or belligerent and in urge to exploit ours. The framework gives a quantitative solution (a mixed-strategy), which is how frequent we should perform the active SETI. This frequency is roughly proportional to the inverse of the risk, and can be extremely small. However, given the immense amount of stars being scanned, it supports active SETI. The model is compared with simulations, and the possible actions are evaluated through the San Marino scale, measuring the risks of messaging.},
author = {Vladar, Harold},
journal = {International Journal of Astrobiology},
number = {1},
pages = {53 -- 62},
publisher = {Cambridge University Press},
title = {{The game of active search for extra terrestrial intelligence Breaking the Great Silence }},
doi = {10.1017/S1473550412000407},
volume = {12},
year = {2012},
}
@unpublished{2928,
abstract = { This paper addresses the problem of approximate MAP-MRF inference in general graphical models. Following [36], we consider a family of linear programming relaxations of the problem where each relaxation is specified by a set of nested pairs of factors for which the marginalization constraint needs to be enforced. We develop a generalization of the TRW-S algorithm [9] for this problem, where we use a decomposition into junction chains, monotonic w.r.t. some ordering on the nodes. This generalizes the monotonic chains in [9] in a natural way. We also show how to deal with nested factors in an efficient way. Experiments show an improvement over min-sum diffusion, MPLP and subgradient ascent algorithms on a number of computer vision and natural language processing problems. },
author = {Kolmogorov, Vladimir and Schoenemann, Thomas},
booktitle = {arXiv},
pages = {16},
publisher = {ArXiv},
title = {{Generalized sequential tree-reweighted message passing}},
year = {2012},
}
@inproceedings{2930,
abstract = {In this paper we investigate k-submodular functions. This natural family of discrete functions includes submodular and bisubmodular functions as the special cases k = 1 and k = 2 respectively.
In particular we generalize the known Min-Max-Theorem for submodular and bisubmodular functions. This theorem asserts that the minimum of the (bi)submodular function can be found by solving a maximization problem over a (bi)submodular polyhedron. We define a k-submodular polyhedron, prove a Min-Max-Theorem for k-submodular functions, and give a greedy algorithm to construct the vertices of the polyhedron.
},
author = {Huber, Anna and Kolmogorov, Vladimir},
location = {Athens, Greece},
pages = {451 -- 462},
publisher = {Springer},
title = {{Towards minimizing k-submodular functions}},
doi = {10.1007/978-3-642-32147-4_40},
volume = {7422},
year = {2012},
}
@article{2931,
abstract = {In this paper, we present a new approach for establishing correspondences between sparse image features related by an unknown nonrigid mapping and corrupted by clutter and occlusion, such as points extracted from images of different instances of the same object category. We formulate this matching task as an energy minimization problem by defining an elaborate objective function of the appearance and the spatial arrangement of the features. Optimization of this energy is an instance of graph matching, which is in general an NP-hard problem. We describe a novel graph matching optimization technique, which we refer to as dual decomposition (DD), and demonstrate on a variety of examples that this method outperforms existing graph matching algorithms. In the majority of our examples, DD is able to find the global minimum within a minute. The ability to globally optimize the objective allows us to accurately learn the parameters of our matching model from training examples. We show on several matching tasks that our learned model yields results superior to those of state-of-the-art methods.
},
author = {Torresani, Lorenzo and Kolmogorov, Vladimir and Rother, Carsten},
journal = {IEEE Transactions on Pattern Analysis and Machine Intelligence},
number = {2},
pages = {259 -- 271},
publisher = {IEEE},
title = {{A dual decomposition approach to feature correspondence}},
doi = {10.1109/TPAMI.2012.105},
volume = {35},
year = {2012},
}
@inproceedings{2936,
abstract = {The notion of delays arises naturally in many computational models, such as, in the design of circuits, control systems, and dataflow languages. In this work, we introduce automata with delay blocks (ADBs), extending finite state automata with variable time delay blocks, for deferring individual transition output symbols, in a discrete-time setting. We show that the ADB languages strictly subsume the regular languages, and are incomparable in expressive power to the context-free languages. We show that ADBs are closed under union, concatenation and Kleene star, and under intersection with regular languages, but not closed under complementation and intersection with other ADB languages. We show that the emptiness and the membership problems are decidable in polynomial time for ADBs, whereas the universality problem is undecidable. Finally we consider the linear-time model checking problem, i.e., whether the language of an ADB is contained in a regular language, and show that the model checking problem is PSPACE-complete. Copyright 2012 ACM.},
author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Prabhu, Vinayak},
booktitle = {roceedings of the tenth ACM international conference on Embedded software},
location = {Tampere, Finland},
pages = {43 -- 52},
publisher = {ACM},
title = {{Finite automata with time delay blocks}},
doi = {10.1145/2380356.2380370},
year = {2012},
}
@inproceedings{2937,
abstract = {Developers building cryptography into security-sensitive applications face a daunting task. Not only must they understand the security guarantees delivered by the constructions they choose, they must also implement and combine them correctly and efficiently. Cryptographic compilers free developers from this task by turning high-level specifications of security goals into efficient implementations. Yet, trusting such tools is hard as they rely on complex mathematical machinery and claim security properties that are subtle and difficult to verify. In this paper we present ZKCrypt, an optimizing cryptographic compiler achieving an unprecedented level of assurance without sacrificing practicality for a comprehensive class of cryptographic protocols, known as Zero-Knowledge Proofs of Knowledge. The pipeline of ZKCrypt integrates purpose-built verified compilers and verifying compilers producing formal proofs in the CertiCrypt framework. By combining the guarantees delivered by each stage, ZKCrypt provides assurance that the output implementation securely realizes the abstract proof goal given as input. We report on the main characteristics of ZKCrypt, highlight new definitions and concepts at its foundations, and illustrate its applicability through a representative example of an anonymous credential system.},
author = {Almeida, José and Barbosa, Manuel and Bangerter, Endre and Barthe, Gilles and Krenn, Stephan and Béguelin, Santiago},
booktitle = {Proceedings of the 2012 ACM conference on Computer and communications security},
location = {Raleigh, NC, USA},
pages = {488 -- 500},
publisher = {ACM},
title = {{Full proof cryptography: Verifiable compilation of efficient zero-knowledge protocols}},
doi = {10.1145/2382196.2382249},
year = {2012},
}
@article{2938,
abstract = {Social insects have a very high potential to become invasive pest species. Here, we explore how their social lifestyle and their interaction with parasites may contribute to this invasive success. Similar to solitary species, parasite release followed by the evolution of increased competitive ability can promote establishment of introduced social insect hosts in their introduced range. Genetic bottlenecks during introduction of low numbers of founder individuals decrease the genetic diversity at three levels: the population, the colony and the individual, with the colony level being specific to social insects. Reduced genetic diversity can affect both the individual immune system and the collective colony-level disease defences (social immunity). Still, the dual immune system is likely to make social insects more robust to parasite attack. Changes in social structure from small, family-based, territorially aggressive societies in native populations towards huge networks of cooperating nests (unicoloniality) occur in some invasive social insects, for example, most invasive ants and some termites. Unicoloniality is likely to affect disease dynamics in multiple ways. The free exchange of individuals within the population leads to an increased genetic heterogeneity among individuals of a single nest, thereby decreasing disease transmission. However, the multitude of reproductively active queens per colony buffers the effect of individual diseased queens and their offspring, which may result in a higher level of vertical disease transmission in unicolonial societies. Lastly, unicoloniality provides a competitive advantage over native species, allowing them to quickly become the dominant species in the habitat, which in turn selects for parasite adaptation to this common host genotype and thus eventually a high parasite pressure. Overall, invasions by insect societies are characterized by general features applying to all introduced species, as well as idiosyncrasies that emerge from their social lifestyle. It is important to study these effects in concert to be able to develop efficient management and biocontrol strategies. © 2012 British Ecological Society.},
author = {Ugelvig, Line V and Cremer, Sylvia},
journal = {Functional Ecology},
number = {6},
pages = {1300 -- 1312},
publisher = {Wiley-Blackwell},
title = {{Effects of social immunity and unicoloniality on host parasite interactions in invasive insect societies}},
doi = {10.1111/1365-2435.12013},
volume = {26},
year = {2012},
}
@article{2941,
author = {Dolbilin, Nikolai and Edelsbrunner, Herbert and Musin, Oleg},
journal = {Russian Mathematical Surveys},
number = {4},
pages = {781 -- 783},
publisher = {IOP Publishing},
title = {{On the optimality of functionals over triangulations of Delaunay sets}},
doi = {10.1070/RM2012v067n04ABEH004807},
volume = {67},
year = {2012},
}
@inproceedings{2942,
abstract = {Interface theories provide a formal framework for component-based development of software and hardware which supports the incremental design of systems and the independent implementability of components. These capabilities are ensured through mathematical properties of the parallel composition operator and the refinement relation for components. More recently, a conjunction operation was added to interface theories in order to provide support for handling multiple viewpoints, requirements engineering, and component reuse. Unfortunately, the conjunction operator does not allow independent implementability in general. In this paper, we study conditions that need to be imposed on interface models in order to enforce independent implementability with respect to conjunction. We focus on multiple viewpoint specifications and propose a new compatibility criterion between two interfaces, which we call orthogonality. We show that orthogonal interfaces can be refined separately, while preserving both orthogonality and composability with other interfaces. We illustrate the independent implementability of different viewpoints with a FIFO buffer example.},
author = {Henzinger, Thomas A and Nickovic, Dejan},
booktitle = { Conference proceedings Monterey Workshop 2012},
location = {Oxford, UK},
pages = {380 -- 395},
publisher = {Springer},
title = {{Independent implementability of viewpoints}},
doi = {10.1007/978-3-642-34059-8_20},
volume = {7539},
year = {2012},
}
@article{2943,
abstract = {We examine whether the Escherichia coli chromosome is folded into a self-adherent nucleoprotein complex, or alternately is a confined but otherwise unconstrained self-avoiding polymer. We address this through in vivo visualization, using an inducible GFP fusion to the nucleoid-associated protein Fis to non-specifically decorate the entire chromosome. For a range of different growth conditions, the chromosome is a compact structure that does not fill the volume of the cell, and which moves from the new pole to the cell centre. During rapid growth, chromosome segregation occurs well before cell division, with daughter chromosomes coupled by a thin inter-daughter filament before complete segregation, whereas during slow growth chromosomes stay adjacent until cell division occurs. Image correlation analysis indicates that sub-nucleoid structure is stable on a 1min timescale, comparable to the timescale for redistribution time measured for GFP-Fis after photobleaching. Optical deconvolution and writhe calculation analysis indicate that the nucleoid has a large-scale coiled organization rather than being an amorphous mass. Our observations are consistent with the chromosome having a self-adherent filament organization.},
author = {Hadizadeh Yazdi, Nastaran and Guet, Calin C and Johnson, Reid and Marko, John},
journal = {Molecular Microbiology},
number = {6},
pages = {1318 -- 1333},
publisher = {Wiley-Blackwell},
title = {{Variation of the folding and dynamics of the Escherichia coli chromosome with growth conditions}},
doi = {10.1111/mmi.12071},
volume = {86},
year = {2012},
}
@article{2945,
abstract = {In search of foreign antigens, lymphocytes recirculate from the blood, through lymph nodes, into lymphatics and back to the blood. Dendritic cells also migrate to lymph nodes for optimal interaction with lymphocytes. This continuous trafficking of immune cells into and out of lymph nodes is essential for immune surveillance of foreign invaders. In this article, we review our current understanding of the functions of high endothelial venules (HEVs), stroma and lymphatics in the entry, positioning and exit of immune cells in lymph nodes during homeostasis, and we highlight the unexpected role of dendritic cells in the control of lymphocyte homing through HEVs.},
author = {Girard, Jean and Moussion, Christine and Förster, Reinhold},
journal = {Nature Reviews Immunology},
number = {11},
pages = {762 -- 773},
publisher = {Nature Publishing Group},
title = {{HEVs, lymphatics and homeostatic immune cell trafficking in lymph nodes}},
doi = {10.1038/nri3298},
volume = {12},
year = {2012},
}
@article{2946,
abstract = {MicroRNAs (miRNAs) are small noncoding RNAs that function in literally all cellular processes. miRNAs interact with Argonaute (Ago) proteins and guide them to specific target sites located in the 3′-untranslated region (3′-UTR) of target mRNAs leading to translational repression and deadenylation-induced mRNA degradation. Most miRNAs are processed from hairpin-structured precursors by the consecutive action of the RNase III enzymes Drosha and Dicer. However, processing of miR-451 is Dicer independent and cleavage is mediated by the endonuclease Ago2. Here we have characterized miR-451 sequence and structure requirements for processing as well as sorting of miRNAs into different Ago proteins. Pre-miR-451 appears to be optimized for Ago2 cleavage and changes result in reduced processing. In addition, we show that the mature miR-451 only associates with Ago2 suggesting that mature miRNAs are not exchanged between different members of the Ago protein family. Based on cloning and deep sequencing of endogenous miRNAs associated with Ago1-3, we do not find evidence for miRNA sorting in human cells. However, Ago identity appears to influence the length of some miRNAs, while others remain unaffected.},
author = {Dueck, Anne and Ziegler, Christian and Eichner, Alexander and Berezikov, Eugène and Meister, Gunter},
journal = {Nucleic Acids Research},
number = {19},
pages = {9850 -- 9862},
publisher = {Oxford University Press},
title = {{MicroRNAs associated with the different human Argonaute proteins}},
doi = {10.1093/nar/gks705},
volume = {40},
year = {2012},
}
@inproceedings{2947,
abstract = {We introduce games with probabilistic uncertainty, a model for controller synthesis in which the controller observes the state through imprecise sensors that provide correct information about the current state with a fixed probability. That is, in each step, the sensors return an observed state, and given the observed state, there is a probability distribution (due to the estimation error) over the actual current state. The controller must base its decision on the observed state (rather than the actual current state, which it does not know). On the other hand, we assume that the environment can perfectly observe the current state. We show that controller synthesis for qualitative ω-regular objectives in our model can be reduced in polynomial time to standard partial-observation stochastic games, and vice-versa. As a consequence we establish the precise decidability frontier for the new class of games, and establish optimal complexity results for all the decidable problems.},
author = {Chatterjee, Krishnendu and Chmelik, Martin and Majumdar, Ritankar},
location = {Thiruvananthapuram, India},
pages = {385 -- 399},
publisher = {Springer},
title = {{Equivalence of games with probabilistic uncertainty and partial observation games}},
doi = {10.1007/978-3-642-33386-6_30},
volume = {7561},
year = {2012},
}
@article{2949,
author = {Dupret, David and Csicsvari, Jozsef L},
journal = {Nature Neuroscience},
number = {11},
pages = {1471 -- 1472},
publisher = {Nature Publishing Group},
title = {{The medial entorhinal cortex keeps Up}},
doi = {10.1038/nn.3245},
volume = {15},
year = {2012},
}
@article{2950,
abstract = {Contractile actomyosin rings drive various fundamental morphogenetic processes ranging from cytokinesis to wound healing. Actomyosin rings are generally thought to function by circumferential contraction. Here, we show that the spreading of the enveloping cell layer (EVL) over the yolk cell during zebrafish gastrulation is driven by a contractile actomyosin ring. In contrast to previous suggestions, we find that this ring functions not only by circumferential contraction but also by a flow-friction mechanism. This generates a pulling force through resistance against retrograde actomyosin flow. EVL spreading proceeds normally in situations where circumferential contraction is unproductive, indicating that the flow-friction mechanism is sufficient. Thus, actomyosin rings can function in epithelial morphogenesis through a combination of cable-constriction and flow-friction mechanisms.},
author = {Behrndt, Martin and Salbreux, Guillaume and Campinho, Pedro and Hauschild, Robert and Oswald, Felix and Roensch, Julia and Grill, Stephan and Heisenberg, Carl-Philipp J},
journal = {Science},
number = {6104},
pages = {257 -- 260},
publisher = {American Association for the Advancement of Science},
title = {{Forces driving epithelial spreading in zebrafish gastrulation}},
doi = {10.1126/science.1224143},
volume = {338},
year = {2012},
}
@article{2951,
abstract = {Differential cell adhesion and cortex tension are thought to drive cell sorting by controlling cell-cell contact formation. Here, we show that cell adhesion and cortex tension have different mechanical functions in controlling progenitor cell-cell contact formation and sorting during zebrafish gastrulation. Cortex tension controls cell-cell contact expansion by modulating interfacial tension at the contact. By contrast, adhesion has little direct function in contact expansion, but instead is needed to mechanically couple the cortices of adhering cells at their contacts, allowing cortex tension to control contact expansion. The coupling function of adhesion is mediated by E-cadherin and limited by the mechanical anchoring of E-cadherin to the cortex. Thus, cell adhesion provides the mechanical scaffold for cell cortex tension to drive cell sorting during gastrulation.},
author = {Maître, Jean-Léon and Berthoumieux, Hélène and Krens, Gabriel and Salbreux, Guillaume and Julicher, Frank and Paluch, Ewa and Heisenberg, Carl-Philipp J},
journal = {Science},
number = {6104},
pages = {253 -- 256},
publisher = {American Association for the Advancement of Science},
title = {{Adhesion functions in cell sorting by mechanically coupling the cortices of adhering cells}},
doi = {10.1126/science.1225399},
volume = {338},
year = {2012},
}