@inproceedings{3250,
abstract = {The Learning Parity with Noise (LPN) problem has recently found many applications in cryptography as the hardness assumption underlying the constructions of "provably secure" cryptographic schemes like encryption or authentication protocols. Being provably secure means that the scheme comes with a proof showing that the existence of an efficient adversary against the scheme implies that the underlying hardness assumption is wrong. LPN based schemes are appealing for theoretical and practical reasons. On the theoretical side, LPN based schemes offer a very strong security guarantee. The LPN problem is equivalent to the problem of decoding random linear codes, a problem that has been extensively studied in the last half century. The fastest known algorithms run in exponential time and unlike most number-theoretic problems used in cryptography, the LPN problem does not succumb to known quantum algorithms. On the practical side, LPN based schemes are often extremely simple and efficient in terms of code-size as well as time and space requirements. This makes them prime candidates for light-weight devices like RFID tags, which are too weak to implement standard cryptographic primitives like the AES block-cipher. This talk will be a gentle introduction to provable security using simple LPN based schemes as examples. Starting from pseudorandom generators and symmetric key encryption, over secret-key authentication protocols, and, if time admits, touching on recent constructions of public-key identification, commitments and zero-knowledge proofs.},
author = {Pietrzak, Krzysztof Z},
location = {Špindlerův Mlýn, Czech Republic},
pages = {99 -- 114},
publisher = {Springer},
title = {{Cryptography from learning parity with noise}},
doi = {10.1007/978-3-642-27660-6_9},
volume = {7147},
year = {2012},
}
@article{3248,
abstract = {We describe RTblob, a high speed vision system that detects objects in cluttered scenes based on their color and shape at a speed of over 800 frames/s. Because the system is available as open-source software and relies only on off-the-shelf PC hardware components, it can provide the basis for multiple application scenarios. As an illustrative example, we show how RTblob can be used in a robotic table tennis scenario to estimate ball trajectories through 3D space simultaneously from four cameras images at a speed of 200 Hz.},
author = {Lampert, Christoph and Peters, Jan},
journal = {Journal of Real-Time Image Processing},
number = {1},
pages = {31 -- 41},
publisher = {Springer},
title = {{Real-time detection of colored objects in multiple camera streams with off-the-shelf hardware components}},
doi = {10.1007/s11554-010-0168-3},
volume = {7},
year = {2012},
}
@article{3243,
author = {Danowski, Patrick},
journal = {Büchereiperspektiven},
pages = {11},
publisher = {Buchereiverband Österreichs},
title = {{Zwischen Technologie und Information}},
volume = {1/2012},
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},
}
@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},
}
@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},
}
@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{3128,
abstract = {We consider two-player zero-sum stochastic games on graphs with ω-regular winning conditions specified as parity objectives. These games have applications in the design and control of reactive systems. We survey the complexity results for the problem of deciding the winner in such games, and in classes of interest obtained as special cases, based on the information and the power of randomization available to the players, on the class of objectives and on the winning mode. On the basis of information, these games can be classified as follows: (a) partial-observation (both players have partial view of the game); (b) one-sided partial-observation (one player has partial-observation and the other player has complete-observation); and (c) complete-observation (both players have complete view of the game). The one-sided partial-observation games have two important subclasses: the one-player games, known as partial-observation Markov decision processes (POMDPs), and the blind one-player games, known as probabilistic automata. On the basis of randomization, (a) the players may not be allowed to use randomization (pure strategies), or (b) they may choose a probability distribution over actions but the actual random choice is external and not visible to the player (actions invisible), or (c) they may use full randomization. Finally, various classes of games are obtained by restricting the parity objective to a reachability, safety, Büchi, or coBüchi condition. We also consider several winning modes, such as sure-winning (i.e., all outcomes of a strategy have to satisfy the winning condition), almost-sure winning (i.e., winning with probability 1), limit-sure winning (i.e., winning with probability arbitrarily close to 1), and value-threshold winning (i.e., winning with probability at least ν, where ν is a given rational). },
author = {Chatterjee, Krishnendu and Doyen, Laurent and Henzinger, Thomas A},
journal = {Formal Methods in System Design},
number = {2},
pages = {268 -- 284},
publisher = {Springer},
title = {{A survey of partial-observation stochastic parity games}},
doi = {10.1007/s10703-012-0164-2},
volume = {43},
year = {2012},
}
@inproceedings{3135,
abstract = {We introduce consumption games, a model for discrete interactive system with multiple resources that are consumed or reloaded independently. More precisely, a consumption game is a finite-state graph where each transition is labeled by a vector of resource updates, where every update is a non-positive number or ω. The ω updates model the reloading of a given resource. Each vertex belongs either to player □ or player ◇, where the aim of player □ is to play so that the resources are never exhausted. We consider several natural algorithmic problems about consumption games, and show that although these problems are computationally hard in general, they are solvable in polynomial time for every fixed number of resource types (i.e., the dimension of the update vectors) and bounded resource updates. },
author = {Brázdil, Brázdil and Chatterjee, Krishnendu and Kučera, Antonín and Novotny, Petr},
location = {Berkeley, CA, USA},
pages = {23 -- 38},
publisher = {Springer},
title = {{Efficient controller synthesis for consumption games with multiple resource types}},
doi = {10.1007/978-3-642-31424-7_8},
volume = {7358},
year = {2012},
}
@inproceedings{3255,
abstract = {In this paper we survey results of two-player games on graphs and Markov decision processes with parity, mean-payoff and energy objectives, and the combination of mean-payoff and energy objectives with parity objectives. These problems have applications in verification and synthesis of reactive systems in resource-constrained environments.},
author = {Chatterjee, Krishnendu and Doyen, Laurent},
location = {Lednice, Czech Republic},
pages = {37 -- 46},
publisher = {Springer},
title = {{Games and Markov decision processes with mean payoff parity and energy parity objectives}},
doi = {10.1007/978-3-642-25929-6_3},
volume = {7119},
year = {2012},
}
@inproceedings{495,
abstract = {An automaton with advice is a finite state automaton which has access to an additional fixed infinite string called an advice tape. We refine the Myhill-Nerode theorem to characterize the languages of finite strings that are accepted by automata with advice. We do the same for tree automata with advice.},
author = {Kruckman, Alex and Rubin, Sasha and Sheridan, John and Zax, Ben},
booktitle = {Proceedings GandALF 2012},
location = {Napoli, Italy},
pages = {238 -- 246},
publisher = {Open Publishing Association},
title = {{A Myhill Nerode theorem for automata with advice}},
doi = {10.4204/EPTCS.96.18},
volume = {96},
year = {2012},
}
@article{6588,
abstract = {First we note that the best polynomial approximation to vertical bar x vertical bar on the set, which consists of an interval on the positive half-axis and a point on the negative half-axis, can be given by means of the classical Chebyshev polynomials. Then we explore the cases when a solution of the related problem on two intervals can be given in elementary functions.},
author = {Pausinger, Florian},
issn = {1812-9471},
journal = {Journal of Mathematical Physics, Analysis, Geometry},
number = {1},
pages = {63--78},
publisher = {B. Verkin Institute for Low Temperature Physics and Engineering},
title = {{Elementary solutions of the Bernstein problem on two intervals}},
volume = {8},
year = {2012},
}
@inproceedings{3270,
abstract = {The persistence diagram of a filtered simplicial com- plex is usually computed by reducing the boundary matrix of the complex. We introduce a simple op- timization technique: by processing the simplices of the complex in decreasing dimension, we can “kill” columns (i.e., set them to zero) without reducing them. This technique completely avoids reduction on roughly half of the columns. We demonstrate that this idea significantly improves the running time of the reduction algorithm in practice. We also give an output-sensitive complexity analysis for the new al- gorithm which yields to sub-cubic asymptotic bounds under certain assumptions.},
author = {Chen, Chao and Kerber, Michael},
location = {Morschach, Switzerland},
pages = {197 -- 200},
publisher = {TU Dortmund},
title = {{Persistent homology computation with a twist}},
year = {2011},
}
@phdthesis{3275,
abstract = {Chemokines organize immune cell trafficking by inducing either directed (tactic) or random (kinetic) migration and by activating integrins in order to support surface adhesion (haptic). Beyond that the same chemokines can establish clearly defined functional areas in secondary lymphoid organs. Until now it is unclear how chemokines can fulfill such diverse functions. One decisive prerequisite to explain these capacities is to know how chemokines are presented in tissue. In theory chemokines could occur either soluble or immobilized, and could be distributed either homogenously or as a concentration gradient. To dissect if and how the presenting mode of chemokines influences immune cells, I tested the response of dendritic cells (DCs) to differentially displayed chemokines. DCs are antigen presenting cells that reside in the periphery and migrate into draining lymph nodes (LNs) once exposed to inflammatory stimuli to activate naïve T cells. DCs are guided to and within the LN by the chemokine receptor CCR7, which has two ligands, the chemokines CCL19 and CCL21. Both CCR7 ligands are expressed by fibroblastic reticular cells in the LN, but differ in their ability to bind to heparan sulfate residues. CCL21 has a highly charged C-terminal extension, which mediates binding to anionic surfaces, whereas CCL19 is lacking such residues and likely distributes as a soluble molecule. This study shows that surface-bound CCL21 causes random, haptokinetic DC motility, which is confined to the chemokine coated area by insideout activation of β2 integrins that mediate cell binding to the surface. CCL19 on the other hand forms concentration gradients which trigger directional, chemotactic movement, but no surface adhesion. In addition DCs can actively manipulate this system by recruiting and activating serine proteases on their surfaces, which create - by proteolytically removing the adhesive C-terminus - a solubilized variant of CCL21 that functionally resembles CCL19. By generating a CCL21 concentration gradient DCs establish a positive feedback loop to recruit further DCs from the periphery to the CCL21 coated region. In addition DCs can sense chemotactic gradients as well as immobilized haptokinetic fields at the same time and integrate these signals. The result is chemotactically biased haptokinesis - directional migration confined to a chemokine coated track or area - which could explain the dynamic but spatially tightly controlled swarming leukocyte locomotion patterns that have been observed in lymphatic organs by intravital microscopists. The finding that DCs can approach soluble cues in a non-adhesive manner while they attach to surfaces coated with immobilized cues raises the question how these cells transmit intracellular forces to the environment, especially in the non-adherent migration mode. In order to migrate, cells have to generate and transmit force to the extracellular substrate. Force transmission is the prerequisite to procure an expansion of the leading edge and a forward motion of the whole cell body. In the current conceptions actin polymerization at the leading edge is coupled to extracellular ligands via the integrin family of transmembrane receptors, which allows the transmission of intracellular force. Against the paradigm of force transmission during migration, leukocytes, like DCs, are able to migrate in threedimensional environments without using integrin transmembrane receptors (Lämmermann et al., 2008). This reflects the biological function of leukocytes, as they can invade almost all tissues, whereby their migration has to be independent from the extracellular environment. How the cells can achieve this is unclear. For this study I examined DC migration in a defined threedimensional environment and highlighted actin-dynamics with the probe Lifeact-GFP. The result was that chemotactic DCs can switch between integrin-dependent and integrin- independent locomotion and can thereby adapt to the adhesive properties of their environment. If the cells are able to couple their actin cytoskeleton to the substrate, actin polymerization is entirely converted into protrusion. Without coupling the actin cortex undergoes slippage and retrograde actin flow can be observed. But retrograde actin flow can be completely compensated by higher actin polymerization rate keeping the migration velocity and the shape of the cells unaltered. Mesenchymal cells like fibroblast cannot balance the loss of adhesive interaction, cannot protrude into open space and, therefore, strictly depend on integrinmediated force coupling. This leukocyte specific phenomenon of “adaptive force transmission” endows these cells with the unique ability to transit and invade almost every type of tissue. },
author = {Schumann, Kathrin},
pages = {141},
publisher = {IST Austria},
title = {{The role of chemotactic gradients in dendritic cell migration}},
year = {2011},
}
@article{3287,
abstract = {Diffusing membrane constituents are constantly exposed to a variety of forces that influence their stochastic path. Single molecule experiments allow for resolving trajectories at extremely high spatial and temporal accuracy, thereby offering insights into en route interactions of the tracer. In this review we discuss approaches to derive information about the underlying processes, based on single molecule tracking experiments. In particular, we focus on a new versatile way to analyze single molecule diffusion in the absence of a full analytical treatment. The method is based on comprehensive comparison of an experimental data set against the hypothetical outcome of multiple experiments performed on the computer. Since Monte Carlo simulations can be easily and rapidly performed even on state-of-the-art PCs, our method provides a simple way for testing various - even complicated - diffusion models. We describe the new method in detail, and show the applicability on two specific examples: firstly, kinetic rate constants can be derived for the transient interaction of mobile membrane proteins; secondly, residence time and corral size can be extracted for confined diffusion.},
author = {Ruprecht, Verena and Axmann, Markus and Wieser, Stefan and Schuetz, Gerhard},
journal = {Current Protein & Peptide Science},
number = {8},
pages = {714 -- 724},
publisher = {Bentham Science Publishers},
title = {{What can we learn from single molecule trajectories?}},
doi = {10.2174/138920311798841753},
volume = {12},
year = {2011},
}
@inproceedings{3299,
abstract = {We introduce propagation models, a formalism designed to support general and efficient data structures for the transient analysis of biochemical reaction networks. We give two use cases for propagation abstract data types: the uniformization method and numerical integration. We also sketch an implementation of a propagation abstract data type, which uses abstraction to approximate states.},
author = {Henzinger, Thomas A and Mateescu, Maria},
location = {Paris, France},
pages = {1 -- 3},
publisher = {Springer},
title = {{Propagation models for computing biochemical reaction networks}},
doi = {10.1145/2037509.2037510},
year = {2011},
}
@inproceedings{3302,
abstract = {Cloud computing aims to give users virtually unlimited pay-per-use computing resources without the burden of managing the underlying infrastructure. We present a new job execution environment Flextic that exploits scal- able static scheduling techniques to provide the user with a flexible pricing model, such as a tradeoff between dif- ferent degrees of execution speed and execution price, and at the same time, reduce scheduling overhead for the cloud provider. We have evaluated a prototype of Flextic on Amazon EC2 and compared it against Hadoop. For various data parallel jobs from machine learning, im- age processing, and gene sequencing that we considered, Flextic has low scheduling overhead and reduces job du- ration by up to 15% compared to Hadoop, a dynamic cloud scheduler.},
author = {Henzinger, Thomas A and Singh, Anmol and Singh, Vasu and Wies, Thomas and Zufferey, Damien},
pages = {1 -- 6},
publisher = {USENIX},
title = {{Static scheduling in clouds}},
year = {2011},
}
@article{3352,
abstract = {Exploring the connection of biology with reactive systems to better understand living systems.},
author = {Fisher, Jasmin and Harel, David and Henzinger, Thomas A},
journal = {Communications of the ACM},
number = {10},
pages = {72 -- 82},
publisher = {ACM},
title = {{Biology as reactivity}},
doi = {10.1145/2001269.2001289},
volume = {54},
year = {2011},
}
@inproceedings{3319,
abstract = {We address the problem of metric learning for multi-view data, namely the construction of embedding projections from data in different representations into a shared feature space, such that the Euclidean distance in this space provides a meaningful within-view as well as between-view similarity. Our motivation stems from the problem of cross-media retrieval tasks, where the availability of a joint Euclidean distance function is a pre-requisite to allow fast, in particular hashing-based, nearest neighbor queries. We formulate an objective function that expresses the intuitive concept that matching samples are mapped closely together in the output space, whereas non-matching samples are pushed apart, no matter in which view they are available. The resulting optimization problem is not convex, but it can be decomposed explicitly into a convex and a concave part, thereby allowing efficient optimization using the convex-concave procedure. Experiments on an image retrieval task show that nearest-neighbor based cross-view retrieval is indeed possible, and the proposed technique improves the retrieval accuracy over baseline techniques.},
author = {Quadrianto, Novi and Lampert, Christoph},
location = {Bellevue, USA},
pages = {425 -- 432},
publisher = {Omnipress},
title = {{Learning multi-view neighborhood preserving projections}},
year = {2011},
}
@inproceedings{3326,
abstract = {Weighted automata map input words to numerical values. Ap- plications of weighted automata include formal verification of quantitative properties, as well as text, speech, and image processing. A weighted au- tomaton is defined with respect to a semiring. For the tropical semiring, the weight of a run is the sum of the weights of the transitions taken along the run, and the value of a word is the minimal weight of an accepting run on it. In the 90’s, Krob studied the decidability of problems on rational series defined with respect to the tropical semiring. Rational series are strongly related to weighted automata, and Krob’s results apply to them. In par- ticular, it follows from Krob’s results that the universality problem (that is, deciding whether the values of all words are below some threshold) is decidable for weighted automata defined with respect to the tropical semir- ing with domain ∪ {∞}, and that the equality problem is undecidable when the domain is ∪ {∞}. In this paper we continue the study of the borders of decidability in weighted automata, describe alternative and direct proofs of the above results, and tighten them further. Unlike the proofs of Krob, which are algebraic in their nature, our proofs stay in the terrain of state machines, and the reduction is from the halting problem of a two-counter machine. This enables us to significantly simplify Krob’s reasoning, make the un- decidability result accessible to the automata-theoretic community, and strengthen it to apply already to a very simple class of automata: all the states are accepting, there are no initial nor final weights, and all the weights on the transitions are from the set {−1, 0, 1}. The fact we work directly with the automata enables us to tighten also the decidability re- sults and to show that the universality problem for weighted automata defined with respect to the tropical semiring with domain ∪ {∞}, and in fact even with domain ≥0 ∪ {∞}, is PSPACE-complete. Our results thus draw a sharper picture about the decidability of decision problems for weighted automata, in both the front of containment vs. universality and the front of the ∪ {∞} vs. the ∪ {∞} domains.},
author = {Almagor, Shaull and Boker, Udi and Kupferman, Orna},
editor = {Bultan, Tevfik and Hsiung, Pao-Ann},
location = {Taipei, Taiwan},
pages = {482 -- 491},
publisher = {Springer},
title = {{What’s decidable about weighted automata }},
doi = {10.1007/978-3-642-24372-1_37},
volume = {6996},
year = {2011},
}