@inproceedings{2305,
abstract = {We study the complexity of central controller synthesis problems for finite-state Markov decision processes, where the objective is to optimize both the expected mean-payoff performance of the system and its stability. e argue that the basic theoretical notion of expressing the stability in terms of the variance of the mean-payoff (called global variance in our paper) is not always sufficient, since it ignores possible instabilities on respective runs. For this reason we propose alernative definitions of stability, which we call local and hybrid variance, and which express how rewards on each run deviate from the run's own mean-payoff and from the expected mean-payoff, respectively. We show that a strategy ensuring both the expected mean-payoff and the variance below given bounds requires randomization and memory, under all the above semantics of variance. We then look at the problem of determining whether there is a such a strategy. For the global variance, we show that the problem is in PSPACE, and that the answer can be approximated in pseudo-polynomial time. For the hybrid variance, the analogous decision problem is in NP, and a polynomial-time approximating algorithm also exists. For local variance, we show that the decision problem is in NP. Since the overall performance can be traded for stability (and vice versa), we also present algorithms for approximating the associated Pareto curve in all the three cases. Finally, we study a special case of the decision problems, where we require a given expected mean-payoff together with zero variance. Here we show that the problems can be all solved in polynomial time.},
author = {Brázdil, Tomáš and Chatterjee, Krishnendu and Forejt, Vojtěch and Kučera, Antonín},
booktitle = {28th Annual ACM/IEEE Symposium},
location = {New Orleans, LA, United States},
pages = {331 -- 340},
publisher = {IEEE},
title = {{Trading performance for stability in Markov decision processes}},
doi = {10.1109/LICS.2013.39},
year = {2013},
}
@misc{5405,
abstract = {The theory of graph games is the foundation for modeling and synthesizing reactive processes. In the synthesis of stochastic processes, we use 2-1/2-player games where some transitions of the game graph are controlled by two adversarial players, the System and the Environment, and the other transitions are determined probabilistically. We consider 2-1/2-player games where the objective of the System is the conjunction of a qualitative objective (specified as a parity condition) and a quantitative objective (specified as a mean-payoff condition). We establish that the problem of deciding whether the System can ensure that the probability to satisfy the mean-payoff parity objective is at least a given threshold is in NP ∩ coNP, matching the best known bound in the special case of 2-player games (where all transitions are deterministic) with only parity objectives, or with only mean-payoff objectives. We present an algorithm running
in time O(d · n^{2d}·MeanGame) to compute the set of almost-sure winning states from which the objective
can be ensured with probability 1, where n is the number of states of the game, d the number of priorities
of the parity objective, and MeanGame is the complexity to compute the set of almost-sure winning states
in 2-1/2-player mean-payoff games. Our results are useful in the synthesis of stochastic reactive systems
with both functional requirement (given as a qualitative objective) and performance requirement (given
as a quantitative objective).},
author = {Chatterjee, Krishnendu and Doyen, Laurent and Gimbert, Hugo and Oualhadj, Youssouf},
issn = {2664-1690},
pages = {22},
publisher = {IST Austria},
title = {{Perfect-information stochastic mean-payoff parity games}},
doi = {10.15479/AT:IST-2013-128-v1-1},
year = {2013},
}
@misc{5400,
abstract = {We consider partially observable Markov decision processes (POMDPs) with ω-regular conditions specified as parity objectives. The class of ω-regular languages extends regular languages to infinite strings and provides a robust specification language to express all properties used in verification, and parity objectives are canonical forms to express ω-regular conditions. The qualitative analysis problem given a POMDP and a parity objective asks whether there is a strategy to ensure that the objective is satis- fied with probability 1 (resp. positive probability). While the qualitative analysis problems are known to be undecidable even for very special cases of parity objectives, we establish decidability (with optimal complexity) of the qualitative analysis problems for POMDPs with all parity objectives under finite- memory strategies. We establish asymptotically optimal (exponential) memory bounds and EXPTIME- completeness of the qualitative analysis problems under finite-memory strategies for POMDPs with parity objectives.},
author = {Chatterjee, Krishnendu and Chmelik, Martin and Tracol, Mathieu},
issn = {2664-1690},
pages = {41},
publisher = {IST Austria},
title = {{What is decidable about partially observable Markov decision processes with ω-regular objectives}},
doi = {10.15479/AT:IST-2013-109-v1-1},
year = {2013},
}
@inproceedings{2444,
abstract = {We consider two core algorithmic problems for probabilistic verification: the maximal end-component decomposition and the almost-sure reachability set computation for Markov decision processes (MDPs). For MDPs with treewidth k, we present two improved static algorithms for both the problems that run in time O(n·k 2.38·2k ) and O(m·logn· k), respectively, where n is the number of states and m is the number of edges, significantly improving the previous known O(n·k·√n· k) bound for low treewidth. We also present decremental algorithms for both problems for MDPs with constant treewidth that run in amortized logarithmic time, which is a huge improvement over the previously known algorithms that require amortized linear time.},
author = {Chatterjee, Krishnendu and Ła̧Cki, Jakub},
location = {St. Petersburg, Russia},
pages = {543 -- 558},
publisher = {Springer},
title = {{Faster algorithms for Markov decision processes with low treewidth}},
doi = {10.1007/978-3-642-39799-8_36},
volume = {8044},
year = {2013},
}
@article{2824,
abstract = {We study synthesis of controllers for real-time systems, where the objective is to stay in a given safe set. The problem is solved by obtaining winning strategies in the setting of concurrent two player timed automaton games with safety objectives. To prevent a player from winning by blocking time, we restrict each player to strategies that ensure that the player cannot be responsible for causing a Zeno run. We construct winning strategies for the controller which require access only to (1) the system clocks (thus, controllers which require their own internal infinitely precise clocks are not necessary), and (2) a logarithmic (in the number of clocks) number of memory bits (i.e. a linear number of memory states). Precisely, we show that for safety objectives, a memory of size (3 + lg (| C | + 1)) bits suffices for winning controller strategies, where C is the set of clocks of the timed automaton game, significantly improving the previous known exponential memory states bound. We also settle the open question of whether winning region-based strategies require memory for safety objectives by showing with an example the necessity of memory for such strategies to win for safety objectives. Finally, we show that the decision problem of determining if there exists a receptive player-1 winning strategy for safety objectives is EXPTIME-complete over timed automaton games.},
author = {Chatterjee, Krishnendu and Prabhu, Vinayak},
journal = {Information and Computation},
pages = {83--119},
publisher = {Elsevier},
title = {{Synthesis of memory-efficient, clock-memory free, and non-Zeno safety controllers for timed systems}},
doi = {10.1016/j.ic.2013.04.003},
volume = {228-229},
year = {2013},
}
@article{2836,
abstract = {We study the automatic synthesis of fair non-repudiation protocols, a class of fair exchange protocols, used for digital contract signing. First, we show how to specify the objectives of the participating agents and the trusted third party as path formulas in linear temporal logic and prove that the satisfaction of these objectives imply fairness; a property required of fair exchange protocols. We then show that weak (co-operative) co-synthesis and classical (strictly competitive) co-synthesis fail, whereas assume-guarantee synthesis (AGS) succeeds. We demonstrate the success of AGS as follows: (a) any solution of AGS is attack-free; no subset of participants can violate the objectives of the other participants; (b) the Asokan-Shoup-Waidner certified mail protocol that has known vulnerabilities is not a solution of AGS; (c) the Kremer-Markowitch non-repudiation protocol is a solution of AGS; and (d) AGS presents a new and symmetric fair non-repudiation protocol that is attack-free. To our knowledge this is the first application of synthesis to fair non-repudiation protocols, and our results show how synthesis can both automatically discover vulnerabilities in protocols and generate correct protocols. The solution to AGS can be computed efficiently as the secure equilibrium solution of three-player graph games. },
author = {Chatterjee, Krishnendu and Raman, Vishwanath},
journal = {Formal Aspects of Computing},
number = {4},
pages = {825 -- 859},
publisher = {Springer},
title = {{Assume-guarantee synthesis for digital contract signing}},
doi = {10.1007/s00165-013-0283-6},
volume = {26},
year = {2013},
}
@article{2817,
abstract = {The basic idea of evolutionary game theory is that payoff determines reproductive rate. Successful individuals have a higher payoff and produce more offspring. But in evolutionary and ecological situations there is not only reproductive rate but also carrying capacity. Individuals may differ in their exposure to density limiting effects. Here we explore an alternative approach to evolutionary game theory by assuming that the payoff from the game determines the carrying capacity of individual phenotypes. Successful strategies are less affected by density limitation (crowding) and reach higher equilibrium abundance. We demonstrate similarities and differences between our framework and the standard replicator equation. Our equation is defined on the positive orthant, instead of the simplex, but has the same equilibrium points as the replicator equation. Linear stability analysis produces the classical conditions for asymptotic stability of pure strategies, but the stability properties of internal equilibria can differ in the two frameworks. For example, in a two-strategy game with an internal equilibrium that is always stable under the replicator equation, the corresponding equilibrium can be unstable in the new framework resulting in a limit cycle.},
author = {Novak, Sebastian and Chatterjee, Krishnendu and Nowak, Martin},
journal = {Journal of Theoretical Biology},
pages = {26 -- 34},
publisher = {Elsevier},
title = {{Density games}},
doi = {10.1016/j.jtbi.2013.05.029},
volume = {334},
year = {2013},
}
@inproceedings{2886,
abstract = {We focus on the realizability problem of Message Sequence Graphs (MSG), i.e. the problem whether a given MSG specification is correctly distributable among parallel components communicating via messages. This fundamental problem of MSG is known to be undecidable. We introduce a well motivated restricted class of MSG, so called controllable-choice MSG, and show that all its models are realizable and moreover it is decidable whether a given MSG model is a member of this class. In more detail, this class of MSG specifications admits a deadlock-free realization by overloading existing messages with additional bounded control data. We also show that the presented class is the largest known subclass of MSG that allows for deadlock-free realization.},
author = {Chmelik, Martin and Řehák, Vojtěch},
location = {Znojmo, Czech Republic},
pages = {118 -- 130},
publisher = {Springer},
title = {{Controllable-choice message sequence graphs}},
doi = {10.1007/978-3-642-36046-6_12},
volume = {7721},
year = {2013},
}
@inproceedings{2329,
abstract = {Two-player games on graphs are central in many problems in formal verification and program analysis such as synthesis and verification of open systems. In this work, we consider both finite-state game graphs, and recursive game graphs (or pushdown game graphs) that model the control flow of sequential programs with recursion. The objectives we study are multidimensional mean-payoff objectives, where the goal of player 1 is to ensure that the mean-payoff is non-negative in all dimensions. In pushdown games two types of strategies are relevant: (1) global strategies, that depend on the entire global history; and (2) modular strategies, that have only local memory and thus do not depend on the context of invocation. Our main contributions are as follows: (1) We show that finite-state multidimensional mean-payoff games can be solved in polynomial time if the number of dimensions and the maximal absolute value of the weights are fixed; whereas if the number of dimensions is arbitrary, then the problem is known to be coNP-complete. (2) We show that pushdown graphs with multidimensional mean-payoff objectives can be solved in polynomial time. For both (1) and (2) our algorithms are based on hyperplane separation technique. (3) For pushdown games under global strategies both one and multidimensional mean-payoff objectives problems are known to be undecidable, and we show that under modular strategies the multidimensional problem is also undecidable; under modular strategies the one-dimensional problem is NP-complete. We show that if the number of modules, the number of exits, and the maximal absolute value of the weights are fixed, then pushdown games under modular strategies with one-dimensional mean-payoff objectives can be solved in polynomial time, and if either the number of exits or the number of modules is unbounded, then the problem is NP-hard. (4) Finally we show that a fixed parameter tractable algorithm for finite-state multidimensional mean-payoff games or pushdown games under modular strategies with one-dimensional mean-payoff objectives would imply the fixed parameter tractability of parity games.},
author = {Chatterjee, Krishnendu and Velner, Yaron},
location = {Buenos Aires, Argentinia},
pages = {500 -- 515},
publisher = {Springer},
title = {{Hyperplane separation technique for multidimensional mean-payoff games}},
doi = {10.1007/978-3-642-40184-8_35},
volume = {8052},
year = {2013},
}
@article{2831,
abstract = {We consider Markov decision processes (MDPs) with Büchi (liveness) objectives. We consider the problem of computing the set of almost-sure winning states from where the objective can be ensured with probability 1. Our contributions are as follows: First, we present the first subquadratic symbolic algorithm to compute the almost-sure winning set for MDPs with Büchi objectives; our algorithm takes O(n · √ m) symbolic steps as compared to the previous known algorithm that takes O(n 2) symbolic steps, where n is the number of states and m is the number of edges of the MDP. In practice MDPs have constant out-degree, and then our symbolic algorithm takes O(n · √ n) symbolic steps, as compared to the previous known O(n 2) symbolic steps algorithm. Second, we present a new algorithm, namely win-lose algorithm, with the following two properties: (a) the algorithm iteratively computes subsets of the almost-sure winning set and its complement, as compared to all previous algorithms that discover the almost-sure winning set upon termination; and (b) requires O(n · √ K) symbolic steps, where K is the maximal number of edges of strongly connected components (scc's) of the MDP. The win-lose algorithm requires symbolic computation of scc's. Third, we improve the algorithm for symbolic scc computation; the previous known algorithm takes linear symbolic steps, and our new algorithm improves the constants associated with the linear number of steps. In the worst case the previous known algorithm takes 5×n symbolic steps, whereas our new algorithm takes 4×n symbolic steps.},
author = {Chatterjee, Krishnendu and Henzinger, Monika and Joglekar, Manas and Shah, Nisarg},
journal = {Formal Methods in System Design},
number = {3},
pages = {301 -- 327},
publisher = {Springer},
title = {{Symbolic algorithms for qualitative analysis of Markov decision processes with Büchi objectives}},
doi = {10.1007/s10703-012-0180-2},
volume = {42},
year = {2013},
}
@article{2850,
abstract = {Recent work emphasizes that the maximum entropy principle provides a bridge between statistical mechanics models for collective behavior in neural networks and experiments on networks of real neurons. Most of this work has focused on capturing the measured correlations among pairs of neurons. Here we suggest an alternative, constructing models that are consistent with the distribution of global network activity, i.e. the probability that K out of N cells in the network generate action potentials in the same small time bin. The inverse problem that we need to solve in constructing the model is analytically tractable, and provides a natural 'thermodynamics' for the network in the limit of large N. We analyze the responses of neurons in a small patch of the retina to naturalistic stimuli, and find that the implied thermodynamics is very close to an unusual critical point, in which the entropy (in proper units) is exactly equal to the energy. © 2013 IOP Publishing Ltd and SISSA Medialab srl.
},
author = {Tkacik, Gasper and Marre, Olivier and Mora, Thierry and Amodei, Dario and Berry, Michael and Bialek, William},
journal = {Journal of Statistical Mechanics Theory and Experiment},
number = {3},
publisher = {IOP Publishing Ltd.},
title = {{The simplest maximum entropy model for collective behavior in a neural network}},
doi = {10.1088/1742-5468/2013/03/P03011},
volume = {2013},
year = {2013},
}
@article{2010,
abstract = {Many algorithms for inferring causality rely heavily on the faithfulness assumption. The main justification for imposing this assumption is that the set of unfaithful distributions has Lebesgue measure zero, since it can be seen as a collection of hypersurfaces in a hypercube. However, due to sampling error the faithfulness condition alone is not sufficient for statistical estimation, and strong-faithfulness has been proposed and assumed to achieve uniform or high-dimensional consistency. In contrast to the plain faithfulness assumption, the set of distributions that is not strong-faithful has nonzero Lebesgue measure and in fact, can be surprisingly large as we show in this paper. We study the strong-faithfulness condition from a geometric and combinatorial point of view and give upper and lower bounds on the Lebesgue measure of strong-faithful distributions for various classes of directed acyclic graphs. Our results imply fundamental limitations for the PC-algorithm and potentially also for other algorithms based on partial correlation testing in the Gaussian case.},
author = {Uhler, Caroline and Raskutti, Garvesh and Bühlmann, Peter and Yu, Bin},
journal = {The Annals of Statistics},
number = {2},
pages = {436 -- 463},
publisher = {Institute of Mathematical Statistics},
title = {{Geometry of the faithfulness assumption in causal inference}},
doi = {10.1214/12-AOS1080},
volume = {41},
year = {2013},
}
@article{2469,
abstract = {Cadherins are transmembrane proteins that mediate cell–cell adhesion in animals. By regulating contact formation and stability, cadherins play a crucial role in tissue morphogenesis and homeostasis. Here, we review the three major unctions of cadherins in cell–cell contact formation and stability. Two of those functions lead to a decrease in interfacial ension at the forming cell–cell contact, thereby promoting contact expansion — first, by providing adhesion tension that lowers interfacial tension at the cell–cell contact, and second, by signaling to the actomyosin cytoskeleton in order to reduce cortex tension and thus interfacial tension at the contact. The third function of cadherins in cell–cell contact formation is to stabilize the contact by resisting mechanical forces that pull on the contact.},
author = {Maître, Jean-Léon and Heisenberg, Carl-Philipp J},
journal = {Current Biology},
number = {14},
pages = {R626 -- R633},
publisher = {Cell Press},
title = {{Three functions of cadherins in cell adhesion}},
doi = {10.1016/j.cub.2013.06.019},
volume = {23},
year = {2013},
}
@article{2471,
abstract = {The impact of disulfide bonds on protein stability goes beyond simple equilibrium thermodynamics effects associated with the conformational entropy of the unfolded state. Indeed, disulfide crosslinks may play a role in the prevention of dysfunctional association and strongly affect the rates of irreversible enzyme inactivation, highly relevant in biotechnological applications. While these kinetic-stability effects remain poorly understood, by analogy with proposed mechanisms for processes of protein aggregation and fibrillogenesis, we propose that they may be determined by the properties of sparsely-populated, partially-unfolded intermediates. Here we report the successful design, on the basis of high temperature molecular-dynamics simulations, of six thermodynamically and kinetically stabilized variants of phytase from Citrobacter braakii (a biotechnologically important enzyme) with one, two or three engineered disulfides. Activity measurements and 3D crystal structure determination demonstrate that the engineered crosslinks do not cause dramatic alterations in the native structure. The inactivation kinetics for all the variants displays a strongly non-Arrhenius temperature dependence, with the time-scale for the irreversible denaturation process reaching a minimum at a given temperature within the range of the denaturation transition. We show this striking feature to be a signature of a key role played by a partially unfolded, intermediate state/ensemble. Energetic and mutational analyses confirm that the intermediate is highly unfolded (akin to a proposed critical intermediate in the misfolding of the prion protein), a result that explains the observed kinetic stabilization. Our results provide a rationale for the kinetic-stability consequences of disulfide-crosslink engineering and an experimental methodology to arrive at energetic/structural descriptions of the sparsely populated and elusive intermediates that play key roles in irreversible protein denaturation.},
author = {Sanchez Romero, Inmaculada and Ariza, Antonio and Wilson, Keith and Skjøt, Michael and Vind, Jesper and De Maria, Leonardo and Skov, Lars and Sánchez Ruiz, Jose},
journal = {PLoS One},
number = {7},
publisher = {Public Library of Science},
title = {{Mechanism of protein kinetic stabilization by engineered disulfide crosslinks}},
doi = {10.1371/journal.pone.0070013},
volume = {8},
year = {2013},
}
@book{2306,
abstract = {Das Buch ist sowohl eine Einführung in die Themen Linked Data, Open Data und Open Linked Data als es auch den konkreten Bezug auf Bibliotheken behandelt. Hierzu werden konkrete Anwendungsprojekte beschrieben. Der Band wendet sich dabei sowohl an Personen aus der Bibliothekspraxis als auch an Personen aus dem Bibliotheksmanagement, die noch nicht mit dem Thema vertraut sind.},
author = {Danowski, Patrick and Pohl, Adrian},
publisher = {De Gruyter},
title = {{(Open) Linked Data in Bibliotheken}},
doi = {10.1515/9783110278736},
volume = {50},
year = {2013},
}
@article{2286,
abstract = {The spatiotemporal control of cell divisions is a key factor in epithelial morphogenesis and patterning. Mao et al (2013) now describe how differential rates of proliferation within the Drosophila wing disc epithelium give rise to anisotropic tissue tension in peripheral/proximal regions of the disc. Such global tissue tension anisotropy in turn determines the orientation of cell divisions by controlling epithelial cell elongation.},
author = {Campinho, Pedro and Heisenberg, Carl-Philipp J},
journal = {EMBO Journal},
number = {21},
pages = {2783 -- 2784},
publisher = {Wiley-Blackwell},
title = {{The force and effect of cell proliferation}},
doi = {10.1038/emboj.2013.225},
volume = {32},
year = {2013},
}
@inproceedings{2293,
abstract = {Many computer vision problems have an asymmetric distribution of information between training and test time. In this work, we study the case where we are given additional information about the training data, which however will not be available at test time. This situation is called learning using privileged information (LUPI). We introduce two maximum-margin techniques that are able to make use of this additional source of information, and we show that the framework is applicable to several scenarios that have been studied in computer vision before. Experiments with attributes, bounding boxes, image tags and rationales as additional information in object classification show promising results.},
author = {Sharmanska, Viktoriia and Quadrianto, Novi and Lampert, Christoph},
location = {Sydney, Australia},
pages = {825 -- 832},
publisher = {IEEE},
title = {{Learning to rank using privileged information}},
doi = {10.1109/ICCV.2013.107},
year = {2013},
}
@techreport{2274,
abstract = {Proofs of work (PoW) have been suggested by Dwork and Naor (Crypto'92) as protection to a shared resource. The basic idea is to ask the service requestor to dedicate some non-trivial amount of computational work to every request. The original applications included prevention of spam and protection against denial of service attacks. More recently, PoWs have been used to prevent double spending in the Bitcoin digital currency system.
In this work, we put forward an alternative concept for PoWs -- so-called proofs of space (PoS), where a service requestor must dedicate a significant amount of disk space as opposed to computation. We construct secure PoS schemes in the random oracle model, using graphs with high "pebbling complexity" and Merkle hash-trees. },
author = {Dziembowski, Stefan and Faust, Sebastian and Kolmogorov, Vladimir and Pietrzak, Krzysztof Z},
publisher = {IST Austria},
title = {{Proofs of Space}},
year = {2013},
}
@article{2806,
abstract = {A novel Taylor-Couette system has been constructed for investigations of transitional as well as high Reynolds number turbulent flows in very large aspect ratios. The flexibility of the setup enables studies of a variety of problems regarding hydrodynamic instabilities and turbulence in rotating flows. The inner and outer cylinders and the top and bottom endplates can be rotated independently with rotation rates of up to 30 Hz, thereby covering five orders of magnitude in Reynolds numbers (Re = 101-106). The radius ratio can be easily changed, the highest realized one is η = 0.98 corresponding to an aspect ratio of 260 gap width in the vertical and 300 in the azimuthal direction. For η < 0.98 the aspect ratio can be dynamically changed during measurements and complete transparency in the radial direction over the full length of the cylinders is provided by the usage of a precision glass inner cylinder. The temperatures of both cylinders are controlled independently. Overall this apparatus combines an unmatched variety in geometry, rotation rates, and temperatures, which is provided by a sophisticated high-precision bearing system. Possible applications are accurate studies of the onset of turbulence and spatio-temporal intermittent flow patterns in very large domains, transport processes of turbulence at high Re, the stability of Keplerian flows for different boundary conditions, and studies of baroclinic instabilities.},
author = {Avila, Kerstin and Hof, Björn},
journal = {Review of Scientific Instruments},
number = {6},
publisher = {American Institute of Physics},
title = {{High-precision Taylor-Couette experiment to study subcritical transitions and the role of boundary conditions and size effects}},
doi = {10.1063/1.4807704},
volume = {84},
year = {2013},
}
@article{2813,
abstract = {Turbulence is ubiquitous in nature, yet even for the case of ordinary Newtonian fluids like water, our understanding of this phenomenon is limited. Many liquids of practical importance are more complicated (e.g., blood, polymer melts, paints), however; they exhibit elastic as well as viscous characteristics, and the relation between stress and strain is nonlinear. We demonstrate here for a model system of such complex fluids that at high shear rates, turbulence is not simply modified as previously believed but is suppressed and replaced by a different type of disordered motion, elasto-inertial turbulence. Elasto-inertial turbulence is found to occur at much lower Reynolds numbers than Newtonian turbulence, and the dynamical properties differ significantly. The friction scaling observed coincides with the so-called "maximum drag reduction" asymptote, which is exhibited by a wide range of viscoelastic fluids.},
author = {Samanta, Devranjan and Dubief, Yves and Holzner, Markus and Schäfer, Christof and Morozov, Alexander and Wagner, Christian and Hof, Björn},
journal = {PNAS},
number = {26},
pages = {10557 -- 10562},
publisher = {National Academy of Sciences},
title = {{Elasto-inertial turbulence}},
doi = {10.1073/pnas.1219666110},
volume = {110},
year = {2013},
}
@article{2863,
abstract = {Neural populations encode information about their stimulus in a collective fashion, by joint activity patterns of spiking and silence. A full account of this mapping from stimulus to neural activity is given by the conditional probability distribution over neural codewords given the sensory input. For large populations, direct sampling of these distributions is impossible, and so we must rely on constructing appropriate models. We show here that in a population of 100 retinal ganglion cells in the salamander retina responding to temporal white-noise stimuli, dependencies between cells play an important encoding role. We introduce the stimulus-dependent maximum entropy (SDME) model—a minimal extension of the canonical linear-nonlinear model of a single neuron, to a pairwise-coupled neural population. We find that the SDME model gives a more accurate account of single cell responses and in particular significantly outperforms uncoupled models in reproducing the distributions of population codewords emitted in response to a stimulus. We show how the SDME model, in conjunction with static maximum entropy models of population vocabulary, can be used to estimate information-theoretic quantities like average surprise and information transmission in a neural population.},
author = {Granot Atedgi, Einat and Tkacik, Gasper and Segev, Ronen and Schneidman, Elad},
journal = {PLoS Computational Biology},
number = {3},
publisher = {Public Library of Science},
title = {{Stimulus-dependent maximum entropy models of neural population codes}},
doi = {10.1371/journal.pcbi.1002922},
volume = {9},
year = {2013},
}
@article{2882,
abstract = {Gravitropic bending of plant organs is mediated by an asymmetric signaling of the plant hormone auxin between the upper and lower side of the respective organ. Here, we show that also another plant hormone, gibberellic acid (GA), shows asymmetric action during gravitropic responses. Immunodetection using an antibody against GA and monitoring GA signaling output by downstream degradation of DELLA proteins revealed an asymmetric GA distribution and response with the maximum at the lower side of gravistimulated roots. Genetic or pharmacological manipulation of GA levels or response affects gravity-mediated auxin redistribution and root bending response. The higher GA levels at the lower side of the root correlate with increased amounts of PIN-FORMED2 (PIN2) auxin transporter at the plasma membrane. The observed increase in PIN2 stability is caused by a specific GA effect on trafficking of PIN proteins to lytic vacuoles that presumably occurs downstream of brefeldin A-sensitive endosomes. Our results suggest that asymmetric auxin distribution instructive for gravity-induced differential growth is consolidated by the asymmetric action of GA that stabilizes the PIN-dependent auxin stream along the lower side of gravistimulated roots.},
author = {Löfke, Christian and Zwiewka, Marta and Heilmann, Ingo and Van Montagu, Marc and Teichmann, Thomas and Friml, Jirí},
journal = {PNAS},
number = {9},
pages = {3627 -- 3632},
publisher = {National Academy of Sciences},
title = {{Asymmetric gibberellin signaling regulates vacuolar trafficking of PIN auxin transporters during root gravitropism}},
doi = {10.1073/pnas.1300107110},
volume = {110},
year = {2013},
}
@inbook{2907,
abstract = {Sex and recombination are among the most striking features of the living world, and they play a crucial role in allowing the evolution of complex adaptation. The sharing of genomes through the sexual union of different individuals requires elaborate behavioral and physiological adaptations. At the molecular level, the alignment of two DNA double helices, followed by their precise cutting and rejoining, is an extraordinary feat. Sex and recombination have diverse—and often surprising—evolutionary consequences: distinct sexes, elaborate mating displays, selfish genetic elements, and so on.},
author = {Barton, Nicholas H},
booktitle = {The Princeton Guide to Evolution},
isbn = {9780691149776},
pages = {328 -- 333},
publisher = {Princeton University Press},
title = {{Recombination and sex}},
year = {2013},
}
@article{2914,
abstract = {The scale invariance of natural images suggests an analogy to the statistical mechanics of physical systems at a critical point. Here we examine the distribution of pixels in small image patches and show how to construct the corresponding thermodynamics. We find evidence for criticality in a diverging specific heat, which corresponds to large fluctuations in how "surprising" we find individual images, and in the quantitative form of the entropy vs energy. We identify special image configurations as local energy minima and show that average patches within each basin are interpretable as lines and edges in all orientations.},
author = {Stephens, Greg and Mora, Thierry and Tkacik, Gasper and Bialek, William},
journal = {Physical Review Letters},
number = {1},
publisher = {American Physical Society},
title = {{Statistical thermodynamics of natural images}},
doi = {10.1103/PhysRevLett.110.018701},
volume = {110},
year = {2013},
}
@article{2832,
abstract = {PIN-FORMED (PIN) proteins localize asymmetrically at the plasma membrane and mediate intercellular polar transport of the plant hormone auxin that is crucial for a multitude of developmental processes in plants. PIN localization is under extensive control by environmental or developmental cues, but mechanisms regulating PIN localization are not fully understood. Here we show that early endosomal components ARF GEF BEN1 and newly identified Sec1/Munc18 family protein BEN2 are involved in distinct steps of early endosomal trafficking. BEN1 and BEN2 are collectively required for polar PIN localization, for their dynamic repolarization, and consequently for auxin activity gradient formation and auxin-related developmental processes including embryonic patterning, organogenesis, and vasculature venation patterning. These results show that early endosomal trafficking is crucial for cell polarity and auxin-dependent regulation of plant architecture.},
author = {Tanaka, Hirokazu and Kitakura, Saeko and Rakusová, Hana and Uemura, Tomohiro and Feraru, Mugurel and De Rycke, Riet and Robert, Stéphanie and Kakimoto, Tatsuo and Friml, Jirí},
journal = {PLoS Genetics},
number = {5},
publisher = {Public Library of Science},
title = {{Cell polarity and patterning by PIN trafficking through early endosomal compartments in arabidopsis thaliana}},
doi = {10.1371/journal.pgen.1003540},
volume = {9},
year = {2013},
}
@article{2837,
abstract = {We consider a general class of N × N random matrices whose entries hij are independent up to a symmetry constraint, but not necessarily identically distributed. Our main result is a local semicircle law which improves previous results [17] both in the bulk and at the edge. The error bounds are given in terms of the basic small parameter of the model, maxi,j E|hij|2. As a consequence, we prove the universality of the local n-point correlation functions in the bulk spectrum for a class of matrices whose entries do not have comparable variances, including random band matrices with band width W ≫N1-εn with some εn > 0 and with a negligible mean-field component. In addition, we provide a coherent and pedagogical proof of the local semicircle law, streamlining and strengthening previous arguments from [17, 19, 6].},
author = {Erdös, László and Knowles, Antti and Yau, Horng and Yin, Jun},
journal = {Electronic Journal of Probability},
number = {59},
pages = {1--58},
publisher = {Institute of Mathematical Statistics},
title = {{The local semicircle law for a general class of random matrices}},
doi = {10.1214/EJP.v18-2473},
volume = {18},
year = {2013},
}
@article{2856,
abstract = {G protein–coupled receptors (GPCRs), the largest family of membrane signaling proteins, respond to neurotransmitters, hormones and small environmental molecules. The neuronal function of many GPCRs has been difficult to resolve because of an inability to gate them with subtype specificity, spatial precision, speed and reversibility. To address this, we developed an approach for opto-chemical engineering of native GPCRs. We applied this to the metabotropic glutamate receptors (mGluRs) to generate light-agonized and light-antagonized mGluRs (LimGluRs). The light-agonized LimGluR2, on which we focused, was fast, bistable and supported multiple rounds of on/off switching. Light gated two of the primary neuronal functions of mGluR2: suppression of excitability and inhibition of neurotransmitter release. We found that the light-antagonized tool LimGluR2-block was able to manipulate negative feedback of synaptically released glutamate on transmitter release. We generalized the optical control to two additional family members: mGluR3 and mGluR6. This system worked in rodent brain slices and in zebrafish in vivo, where we found that mGluR2 modulated the threshold for escape behavior. These light-gated mGluRs pave the way for determining the roles of mGluRs in synaptic plasticity, memory and disease.},
author = {Levitz, Joshua and Pantoja, Carlos and Gaub, Benjamin and Janovjak, Harald L and Reiner, Andreas and Hoagland, Adam and Schoppik, David and Kane, Brian and Stawski, Philipp and Schier, Alexander and Trauner, Dirk and Isacoff, Ehud},
journal = {Nature Neuroscience},
pages = {507 -- 516},
publisher = {Nature Publishing Group},
title = {{Optical control of metabotropic glutamate receptors}},
doi = {10.1038/nn.3346},
volume = {16},
year = {2013},
}
@article{2844,
abstract = {As soon as a seed germinates, plant growth relates to gravity to ensure that the root penetrates the soil and the shoot expands aerially. Whereas mechanisms of positive and negative orthogravitropism of primary roots and shoots are relatively well understood [1-3], lateral organs often show more complex growth behavior [4]. Lateral roots (LRs) seemingly suppress positive gravitropic growth and show a defined gravitropic set-point angle (GSA) that allows radial expansion of the root system (plagiotropism) [3, 4]. Despite its eminent importance for root architecture, it so far remains completely unknown how lateral organs partially suppress positive orthogravitropism. Here we show that the phytohormone auxin steers GSA formation and limits positive orthogravitropism in LR. Low and high auxin levels/signaling lead to radial or axial root systems, respectively. At a cellular level, it is the auxin transport-dependent regulation of asymmetric growth in the elongation zone that determines GSA. Our data suggest that strong repression of PIN4/PIN7 and transient PIN3 expression limit auxin redistribution in young LR columella cells. We conclude that PIN activity, by temporally limiting the asymmetric auxin fluxes in the tip of LRs, induces transient, differential growth responses in the elongation zone and, consequently, controls root architecture.},
author = {Rosquete, Michel and Von Wangenheim, Daniel and Marhavy, Peter and Barbez, Elke and Stelzer, Ernst and Benková, Eva and Maizel, Alexis and Kleine Vehn, Jürgen},
journal = {Current Biology},
number = {9},
pages = {817 -- 822},
publisher = {Cell Press},
title = {{An auxin transport mechanism restricts positive orthogravitropism in lateral roots}},
doi = {10.1016/j.cub.2013.03.064},
volume = {23},
year = {2013},
}
@article{2851,
abstract = {The number of possible activity patterns in a population of neurons grows exponentially with the size of the population. Typical experiments explore only a tiny fraction of the large space of possible activity patterns in the case of populations with more than 10 or 20 neurons. It is thus impossible, in this undersampled regime, to estimate the probabilities with which most of the activity patterns occur. As a result, the corresponding entropy - which is a measure of the computational power of the neural population - cannot be estimated directly. We propose a simple scheme for estimating the entropy in the undersampled regime, which bounds its value from both below and above. The lower bound is the usual 'naive' entropy of the experimental frequencies. The upper bound results from a hybrid approximation of the entropy which makes use of the naive estimate, a maximum entropy fit, and a coverage adjustment. We apply our simple scheme to artificial data, in order to check their accuracy; we also compare its performance to those of several previously defined entropy estimators. We then apply it to actual measurements of neural activity in populations with up to 100 cells. Finally, we discuss the similarities and differences between the proposed simple estimation scheme and various earlier methods. © 2013 IOP Publishing Ltd and SISSA Medialab srl.},
author = {Berry, Michael and Tkacik, Gasper and Dubuis, Julien and Marre, Olivier and Da Silveira, Ravá},
journal = {Journal of Statistical Mechanics Theory and Experiment},
number = {3},
publisher = {IOP Publishing Ltd.},
title = {{A simple method for estimating the entropy of neural activity}},
doi = {10.1088/1742-5468/2013/03/P03015},
volume = {2013},
year = {2013},
}
@article{2818,
abstract = {Models of neural responses to stimuli with complex spatiotemporal correlation structure often assume that neurons are selective for only a small number of linear projections of a potentially high-dimensional input. In this review, we explore recent modeling approaches where the neural response depends on the quadratic form of the input rather than on its linear projection, that is, the neuron is sensitive to the local covariance structure of the signal preceding the spike. To infer this quadratic dependence in the presence of arbitrary (e.g., naturalistic) stimulus distribution, we review several inference methods, focusing in particular on two information theory–based approaches (maximization of stimulus energy and of noise entropy) and two likelihood-based approaches (Bayesian spike-triggered covariance and extensions of generalized linear models). We analyze the formal relationship between the likelihood-based and information-based approaches to demonstrate how they lead to consistent inference. We demonstrate the practical feasibility of these procedures by using model neurons responding to a flickering variance stimulus.},
author = {Rajan, Kanaka and Marre, Olivier and Tkacik, Gasper},
journal = {Neural Computation},
number = {7},
pages = {1661 -- 1692},
publisher = {MIT Press },
title = {{Learning quadratic receptive fields from neural responses to natural stimuli}},
doi = {10.1162/NECO_a_00463},
volume = {25},
year = {2013},
}
@inproceedings{2940,
abstract = {A chain rule for an entropy notion H(.) states that the entropy H(X) of a variable X decreases by at most l if conditioned on an l-bit string A, i.e., H(X|A)>= H(X)-l. More generally, it satisfies a chain rule for conditional entropy if H(X|Y,A)>= H(X|Y)-l.
All natural information theoretic entropy notions we are aware of (like Shannon or min-entropy) satisfy some kind of chain rule for conditional entropy. Moreover, many computational entropy notions (like Yao entropy, unpredictability entropy and several variants of HILL entropy) satisfy the chain rule for conditional entropy, though here not only the quantity decreases by l, but also the quality of the entropy decreases exponentially in l. However, for
the standard notion of conditional HILL entropy (the computational equivalent of min-entropy) the existence of such a rule was unknown so far.
In this paper, we prove that for conditional HILL entropy no meaningful chain rule exists, assuming the existence of one-way permutations: there exist distributions X,Y,A, where A is a distribution over a single bit, but $H(X|Y)>>H(X|Y,A)$, even if we simultaneously allow for a massive degradation in the quality of the entropy.
The idea underlying our construction is based on a surprising connection between the chain rule for HILL entropy and deniable encryption. },
author = {Krenn, Stephan and Pietrzak, Krzysztof Z and Wadia, Akshay},
editor = {Sahai, Amit},
location = {Tokyo, Japan},
pages = {23 -- 39},
publisher = {Springer},
title = {{A counterexample to the chain rule for conditional HILL entropy, and what deniable encryption has to do with it}},
doi = {10.1007/978-3-642-36594-2_2},
volume = {7785},
year = {2013},
}
@article{2919,
abstract = {The distribution of the phytohormone auxin regulates many aspects of plant development including growth response to gravity. Gravitropic root curvature involves coordinated and asymmetric cell elongation between the lower and upper side of the root, mediated by differential cellular auxin levels. The asymmetry in the auxin distribution is established and maintained by a spatio-temporal regulation of the PIN-FORMED (PIN) auxin transporter activity. We provide novel insights into the complex regulation of PIN abundance and activity during root gravitropism. We show that PIN2 turnover is differentially regulated on the upper and lower side of gravistimulated roots by distinct but partially overlapping auxin feedback mechanisms. In addition to regulating transcription and clathrin-mediated internalization, auxin also controls PIN abundance at the plasma membrane by promoting their vacuolar targeting and degradation. This effect of elevated auxin levels requires the activity of SKP-Cullin-F-box TIR1/AFB (SCF TIR1/AFB)-dependent pathway. Importantly, also suboptimal auxin levels mediate PIN degradation utilizing the same signalling pathway. These feedback mechanisms are functionally important during gravitropic response and ensure fine-tuning of auxin fluxes for maintaining as well as terminating asymmetric growth.},
author = {Baster, Pawel and Robert, Stéphanie and Kleine Vehn, Jürgen and Vanneste, Steffen and Kania, Urszula and Grunewald, Wim and De Rybel, Bert and Beeckman, Tom and Friml, Jirí},
journal = {EMBO Journal},
number = {2},
pages = {260 -- 274},
publisher = {Wiley-Blackwell},
title = {{SCF^TIR1 AFB-auxin signalling regulates PIN vacuolar trafficking and auxin fluxes during root gravitropism}},
doi = {10.1038/emboj.2012.310},
volume = {32},
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{501,
abstract = {All known species of extant tapirs are allopatric: 1 in southeastern Asia and 3 in Central and South America. The fossil record for tapirs, however, is much wider in geographical range, including Europe, Asia, and North and South America, going back to the late Oligocene, making the present distribution a relict of the original one. We here describe a new species of living Tapirus from the Amazon rain forest, the 1st since T. bairdii Gill, 1865, and the 1st new Perissodactyla in more than 100 years, from both morphological and molecular characters. It is shorter in stature than T. terrestris (Linnaeus, 1758) and has distinctive skull morphology, and it is basal to the clade formed by T. terrestris and T. pinchaque (Roulin, 1829). This highlights the unrecognized biodiversity in western Amazonia, where the biota faces increasing threats. Local peoples have long recognized our new species, suggesting a key role for traditional knowledge in understanding the biodiversity of the region.},
author = {Cozzuol, Mario and Clozato, Camila and Holanda, Elizete and Rodrigues, Flávio and Nienow, Samuel and De Thoisy, Benoit and Fernandes Redondo, Rodrigo A and Santos, Fabrício},
journal = {Journal of Mammalogy},
number = {6},
pages = {1331 -- 1345},
publisher = {Oxford University Press},
title = {{A new species of tapir from the Amazon}},
doi = {10.1644/12-MAMM-A-169.1},
volume = {94},
year = {2013},
}
@techreport{5401,
abstract = {This document is created as a part of the project “Repository for Research Data at IST Austria”. It summarises the actual initiatives, projects and standards related to the project. It supports the preparation of standards and specifications for the project, which should be considered and followed to ensure interoperability and visibility of the uploaded data.},
author = {Porsche, Jana},
publisher = {IST Austria},
title = {{Initiatives and projects related to RD}},
year = {2013},
}
@article{828,
abstract = {The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots (LRs) are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation. Within this review, main contributions are presented, from the classical forward genetic screens to the more recent high-throughput approaches, combined with computer model predictions, dissecting how LRs and thereby root system architecture is established and developed.},
author = {Cuesta, Candela and Wabnik, Krzysztof T and Benková, Eva},
journal = {Frontiers in Plant Science},
publisher = {Frontiers Research Foundation},
title = {{Systems approaches to study root architecture dynamics}},
doi = {10.3389/fpls.2013.00537},
volume = {4},
year = {2013},
}
@article{2926,
abstract = {To fight infectious diseases, host immune defenses are employed at multiple levels. Sanitary behavior, such as pathogen avoidance and removal, acts as a first line of defense to prevent infection [1] before activation of the physiological immune system. Insect societies have evolved a wide range of collective hygiene measures and intensive health care toward pathogen-exposed group members [2]. One of the most common behaviors is allogrooming, in which nestmates remove infectious particles from the body surfaces of exposed individuals [3]. Here we show that, in invasive garden ants, grooming of fungus-exposed brood is effective beyond the sheer mechanical removal of fungal conidiospores; it also includes chemical disinfection through the application of poison produced by the ants themselves. Formic acid is the main active component of the poison. It inhibits fungal growth of conidiospores remaining on the brood surface after grooming and also those collected in the mouth of the grooming ant. This dual function is achieved by uptake of the poison droplet into the mouth through acidopore self-grooming and subsequent application onto the infectious brood via brood grooming. This extraordinary behavior extends the current understanding of grooming and the establishment of social immunity in insect societies.},
author = {Tragust, Simon and Mitteregger, Barbara and Barone, Vanessa and Konrad, Matthias and Ugelvig, Line V and Cremer, Sylvia},
journal = {Current Biology},
number = {1},
pages = {76 -- 82},
publisher = {Cell Press},
title = {{Ants disinfect fungus-exposed brood by oral uptake and spread of their poison}},
doi = {10.1016/j.cub.2012.11.034},
volume = {23},
year = {2013},
}
@misc{5406,
abstract = {We consider the distributed synthesis problem fortemporal 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 LTLand 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},
issn = {2664-1690},
pages = {11},
publisher = {IST Austria},
title = {{Distributed synthesis for LTL Fragments}},
doi = {10.15479/AT:IST-2013-130-v1-1},
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},
}
@inproceedings{2298,
abstract = {We present a shape analysis for programs that manipulate overlaid data structures which share sets of objects. The abstract domain contains Separation Logic formulas that (1) combine a per-object separating conjunction with a per-field separating conjunction and (2) constrain a set of variables interpreted as sets of objects. The definition of the abstract domain operators is based on a notion of homomorphism between formulas, viewed as graphs, used recently to define optimal decision procedures for fragments of the Separation Logic. Based on a Frame Rule that supports the two versions of the separating conjunction, the analysis is able to reason in a modular manner about non-overlaid data structures and then, compose information only at a few program points, e.g., procedure returns. We have implemented this analysis in a prototype tool and applied it on several interesting case studies that manipulate overlaid and nested linked lists.
},
author = {Dragoi, Cezara and Enea, Constantin and Sighireanu, Mihaela},
location = {Seattle, WA, United States},
pages = {150 -- 171},
publisher = {Springer},
title = {{Local shape analysis for overlaid data structures}},
doi = {10.1007/978-3-642-38856-9_10},
volume = {7935},
year = {2013},
}
@inproceedings{2301,
abstract = {We describe the design and implementation of P, a domain-specific language to write asynchronous event driven code. P allows the programmer to specify the system as a collection of interacting state machines, which communicate with each other using events. P unifies modeling and programming into one activity for the programmer. Not only can a P program be compiled into executable code, but it can also be tested using model checking techniques. P allows the programmer to specify the environment, used to "close" the system during testing, as nondeterministic ghost machines. Ghost machines are erased during compilation to executable code; a type system ensures that the erasure is semantics preserving. The P language is designed so that a P program can be checked for responsiveness-the ability to handle every event in a timely manner. By default, a machine needs to handle every event that arrives in every state. But handling every event in every state is impractical. The language provides a notion of deferred events where the programmer can annotate when she wants to delay processing an event. The default safety checker looks for presence of unhan-dled events. The language also provides default liveness checks that an event cannot be potentially deferred forever. P was used to implement and verify the core of the USB device driver stack that ships with Microsoft Windows 8. The resulting driver is more reliable and performs better than its prior incarnation (which did not use P); we have more confidence in the robustness of its design due to the language abstractions and verification provided by P.},
author = {Desai, Ankush and Gupta, Vivek and Jackson, Ethan and Qadeer, Shaz and Rajamani, Sriram and Zufferey, Damien},
booktitle = {Proceedings of the 34th ACM SIGPLAN Conference on Programming Language Design and Implementation},
location = {Seattle, WA, United States},
pages = {321 -- 331},
publisher = {ACM},
title = {{P: Safe asynchronous event-driven programming}},
doi = {10.1145/2491956.2462184},
year = {2013},
}
@inproceedings{2243,
abstract = {We show that modal logic over universally first-order definable classes of transitive frames is decidable. More precisely, let K be an arbitrary class of transitive Kripke frames definable by a universal first-order sentence. We show that the global and finite global satisfiability problems of modal logic over K are decidable in NP, regardless of choice of K. We also show that the local satisfiability and the finite local satisfiability problems of modal logic over K are decidable in NEXPTIME.},
author = {Michaliszyn, Jakub and Otop, Jan},
location = {Torino, Italy},
pages = {563 -- 577},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Elementary modal logics over transitive structures}},
doi = {10.4230/LIPIcs.CSL.2013.563},
volume = {23},
year = {2013},
}
@inproceedings{2279,
abstract = {We consider two-player games played on weighted directed graphs with mean-payoff and total-payoff objectives, two classical quantitative objectives. While for single-dimensional games the complexity and memory bounds for both objectives coincide, we show that in contrast to multi-dimensional mean-payoff games that are known to be coNP-complete, multi-dimensional total-payoff games are undecidable. We introduce conservative approximations of these objectives, where the payoff is considered over a local finite window sliding along a play, instead of the whole play. For single dimension, we show that (i) if the window size is polynomial, deciding the winner takes polynomial time, and (ii) the existence of a bounded window can be decided in NP ∩ coNP, and is at least as hard as solving mean-payoff games. For multiple dimensions, we show that (i) the problem with fixed window size is EXPTIME-complete, and (ii) there is no primitive-recursive algorithm to decide the existence of a bounded window.},
author = {Chatterjee, Krishnendu and Doyen, Laurent and Randour, Mickael and Raskin, Jean},
location = {Hanoi, Vietnam},
pages = {118 -- 132},
publisher = {Springer},
title = {{Looking at mean-payoff and total-payoff through windows}},
doi = {10.1007/978-3-319-02444-8_10},
volume = {8172},
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},
}
@inproceedings{2820,
abstract = {In this paper, we introduce the powerful framework of graph games for the analysis of real-time scheduling with firm deadlines. We introduce a novel instance of a partial-observation game that is suitable for this purpose, and prove decidability of all the involved decision problems. We derive a graph game that allows the automated computation of the competitive ratio (along with an optimal witness algorithm for the competitive ratio) and establish an NP-completeness proof for the graph game problem. For a given on-line algorithm, we present polynomial time solution for computing (i) the worst-case utility; (ii) the worst-case utility ratio w.r.t. a clairvoyant off-line algorithm; and (iii) the competitive ratio. A major strength of the proposed approach lies in its flexibility w.r.t. incorporating additional constraints on the adversary and/or the algorithm, including limited maximum or average load, finiteness of periods of overload, etc., which are easily added by means of additional instances of standard objective functions for graph games. },
author = {Chatterjee, Krishnendu and Kößler, Alexander and Schmid, Ulrich},
booktitle = {Proceedings of the 16th International conference on Hybrid systems: Computation and control},
isbn = {978-1-4503-1567-8 },
location = {Philadelphia, PA, United States},
pages = {163 -- 172},
publisher = {ACM},
title = {{Automated analysis of real-time scheduling using graph games}},
doi = {10.1145/2461328.2461356},
year = {2013},
}
@article{2887,
abstract = {Root system growth and development is highly plastic and is influenced by the surrounding environment. Roots frequently grow in heterogeneous environments that include interactions from neighboring plants and physical impediments in the rhizosphere. To investigate how planting density and physical objects affect root system growth, we grew rice in a transparent gel system in close proximity with another plant or a physical object. Root systems were imaged and reconstructed in three dimensions. Root-root interaction strength was calculated using quantitative metrics that characterize the extent towhich the reconstructed root systems overlap each other. Surprisingly, we found the overlap of root systems of the same genotype was significantly higher than that of root systems of different genotypes. Root systems of the same genotype tended to grow toward each other but those of different genotypes appeared to avoid each other. Shoot separation experiments excluded the possibility of aerial interactions, suggesting root communication. Staggered plantings indicated that interactions likely occur at root tips in close proximity. Recognition of obstacles also occurred through root tips, but through physical contact in a size-dependent manner. These results indicate that root systems use two different forms of communication to recognize objects and alter root architecture: root-root recognition, possibly mediated through root exudates, and root-object recognition mediated by physical contact at the root tips. This finding suggests that root tips act as local sensors that integrate rhizosphere information into global root architectural changes.},
author = {Fang, Suqin and Clark, Randy and Zheng, Ying and Iyer Pascuzzi, Anjali and Weitz, Joshua and Kochian, Leon and Edelsbrunner, Herbert and Liao, Hong and Benfey, Philip},
journal = {PNAS},
number = {7},
pages = {2670 -- 2675},
publisher = {National Academy of Sciences},
title = {{Genotypic recognition and spatial responses by rice roots}},
doi = {10.1073/pnas.1222821110},
volume = {110},
year = {2013},
}
@article{2009,
abstract = {Traditional statistical methods for confidentiality protection of statistical databases do not scale well to deal with GWAS databases especially in terms of guarantees regarding protection from linkage to external information. The more recent concept of differential privacy, introduced by the cryptographic community, is an approach which provides a rigorous definition of privacy with meaningful privacy guarantees in the presence of arbitrary external information, although the guarantees may come at a serious price in terms of data utility. Building on such notions, we propose new methods to release aggregate GWAS data without compromising an individual’s privacy. We present methods for releasing differentially private minor allele frequencies, chi-square statistics and p-values. We compare these approaches on simulated data and on a GWAS study of canine hair length involving 685 dogs. We also propose a privacy-preserving method for finding genome-wide associations based on a differentially-private approach to penalized logistic regression.},
author = {Uhler, Caroline and Slavkovic, Aleksandra and Fienberg, Stephen},
journal = {Journal of Privacy and Confidentiality },
number = {1},
pages = {137 -- 166},
publisher = {Carnegie Mellon University},
title = {{Privacy-preserving data sharing for genome-wide association studies}},
doi = {10.29012/jpc.v5i1.629 },
volume = {5},
year = {2013},
}
@inproceedings{2270,
abstract = {Representation languages for coalitional games are a key research area in algorithmic game theory. There is an inher-
ent tradeoff between how general a language is, allowing it to capture more elaborate games, and how hard it is computationally to optimize and solve such games. One prominent such language is the simple yet expressive
Weighted Graph Games (WGGs) representation (Deng and Papadimitriou 1994), which maintains knowledge about synergies between agents in the form of an edge weighted graph. We consider the problem of finding the optimal coalition structure in WGGs. The agents in such games are vertices in a graph, and the value of a coalition is the sum of the weights of the edges present between coalition members. The optimal coalition structure is a partition of the agents to coalitions, that maximizes the sum of utilities obtained by the coalitions. We show that finding the optimal coalition structure is not only hard for general graphs, but is also intractable for restricted families such as planar graphs which are amenable for many other combinatorial problems. We then provide algorithms with constant factor approximations for planar, minorfree and bounded degree graphs.},
author = {Bachrach, Yoram and Kohli, Pushmeet and Kolmogorov, Vladimir and Zadimoghaddam, Morteza},
location = {Bellevue, WA, United States},
pages = {81--87},
publisher = {AAAI Press},
title = {{Optimal Coalition Structures in Cooperative Graph Games}},
year = {2013},
}
@article{2256,
abstract = {Linked (Open) Data - bibliographic data on the Semantic Web. Report of the Working Group on Linked Data to the plenary assembly of the Austrian Library Network (translation of the title). Linked Data stands for a certain approach to publishing data on the Web. The underlying idea is to harmonise heterogeneous data sources of different origin in order to improve their accessibility and interoperability, effectively making them queryable as a big distributed database. This report summarises relevant developments in Europe as well as the Linked Data Working Group‘s strategic and technical considerations regarding the publishing of the Austrian Library Network’s (OBV’s) bibliographic datasets. It concludes with the mutual agreement that the implementation of Linked Data principles within the OBV can only be taken into consideration accompanied by a discussion about the provision of the datasets under a free license.},
author = {Danowski, Patrick and Goldfarb, Doron and Schaffner, Verena and Seidler, Wolfram},
journal = {VÖB Mitteilungen},
number = {3/4},
pages = {559 -- 587},
publisher = {Verein Österreichischer Bibliothekarinnen und Bibliothekare},
title = {{Linked (Open) Data - Bibliographische Daten im Semantic Web}},
volume = {66},
year = {2013},
}
@inproceedings{2244,
abstract = {We consider two systems (α1,...,αm) and (β1,...,βn) of curves drawn on a compact two-dimensional surface ℳ with boundary. Each αi and each βj is either an arc meeting the boundary of ℳ at its two endpoints, or a closed curve. The αi are pairwise disjoint except for possibly sharing endpoints, and similarly for the βj. We want to "untangle" the βj from the αi by a self-homeomorphism of ℳ; more precisely, we seek an homeomorphism φ: ℳ → ℳ fixing the boundary of ℳ pointwise such that the total number of crossings of the αi with the φ(βj) is as small as possible. This problem is motivated by an application in the algorithmic theory of embeddings and 3-manifolds. We prove that if ℳ is planar, i.e., a sphere with h ≥ 0 boundary components ("holes"), then O(mn) crossings can be achieved (independently of h), which is asymptotically tight, as an easy lower bound shows. In general, for an arbitrary (orientable or nonorientable) surface ℳ with h holes and of (orientable or nonorientable) genus g ≥ 0, we obtain an O((m + n)4) upper bound, again independent of h and g. },
author = {Matoušek, Jiří and Sedgwick, Eric and Tancer, Martin and Wagner, Uli},
location = {Bordeaux, France},
pages = {472 -- 483},
publisher = {Springer},
title = {{Untangling two systems of noncrossing curves}},
doi = {10.1007/978-3-319-03841-4_41},
volume = {8242},
year = {2013},
}