@article{1616, abstract = {The hippocampus plays a key role in learning and memory. Previous studies suggested that the main types of principal neurons, dentate gyrus granule cells (GCs), CA3 pyramidal neurons, and CA1 pyramidal neurons, differ in their activity pattern, with sparse firing in GCs and more frequent firing in CA3 and CA1 pyramidal neurons. It has been assumed but never shown that such different activity may be caused by differential synaptic excitation. To test this hypothesis, we performed high-resolution whole-cell patch-clamp recordings in anesthetized rats in vivo. In contrast to previous in vitro data, both CA3 and CA1 pyramidal neurons fired action potentials spontaneously, with a frequency of ∼3–6 Hz, whereas GCs were silent. Furthermore, both CA3 and CA1 cells primarily fired in bursts. To determine the underlying mechanisms, we quantitatively assessed the frequency of spontaneous excitatory synaptic input, the passive membrane properties, and the active membrane characteristics. Surprisingly, GCs showed comparable synaptic excitation to CA3 and CA1 cells and the highest ratio of excitation versus hyperpolarizing inhibition. Thus, differential synaptic excitation is not responsible for differences in firing. Moreover, the three types of hippocampal neurons markedly differed in their passive properties. While GCs showed the most negative membrane potential, CA3 pyramidal neurons had the highest input resistance and the slowest membrane time constant. The three types of neurons also differed in the active membrane characteristics. GCs showed the highest action potential threshold, but displayed the largest gain of the input-output curves. In conclusion, our results reveal that differential firing of the three main types of hippocampal principal neurons in vivo is not primarily caused by differences in the characteristics of the synaptic input, but by the distinct properties of synaptic integration and input-output transformation.}, author = {Kowalski, Janina and Gan, Jian and Jonas, Peter M and Pernia-Andrade, Alejandro}, issn = {1098-1063}, journal = {Hippocampus}, number = {5}, pages = {668 -- 682}, publisher = {Wiley}, title = {{Intrinsic membrane properties determine hippocampal differential firing pattern in vivo in anesthetized rats}}, doi = {10.1002/hipo.22550}, volume = {26}, year = {2016}, } @article{1617, abstract = {We study the discrepancy of jittered sampling sets: such a set P⊂ [0,1]d is generated for fixed m∈ℕ by partitioning [0,1]d into md axis aligned cubes of equal measure and placing a random point inside each of the N=md cubes. We prove that, for N sufficiently large, 1/10 d/N1/2+1/2d ≤EDN∗(P)≤ √d(log N) 1/2/N1/2+1/2d, where the upper bound with an unspecified constant Cd was proven earlier by Beck. Our proof makes crucial use of the sharp Dvoretzky-Kiefer-Wolfowitz inequality and a suitably taylored Bernstein inequality; we have reasons to believe that the upper bound has the sharp scaling in N. Additional heuristics suggest that jittered sampling should be able to improve known bounds on the inverse of the star-discrepancy in the regime N≳dd. We also prove a partition principle showing that every partition of [0,1]d combined with a jittered sampling construction gives rise to a set whose expected squared L2-discrepancy is smaller than that of purely random points.}, author = {Pausinger, Florian and Steinerberger, Stefan}, journal = {Journal of Complexity}, pages = {199 -- 216}, publisher = {Academic Press}, title = {{On the discrepancy of jittered sampling}}, doi = {10.1016/j.jco.2015.11.003}, volume = {33}, year = {2016}, } @article{1620, abstract = {We consider the Bardeen–Cooper–Schrieffer free energy functional for particles interacting via a two-body potential on a microscopic scale and in the presence of weak external fields varying on a macroscopic scale. We study the influence of the external fields on the critical temperature. We show that in the limit where the ratio between the microscopic and macroscopic scale tends to zero, the next to leading order of the critical temperature is determined by the lowest eigenvalue of the linearization of the Ginzburg–Landau equation.}, author = {Frank, Rupert and Hainzl, Christian and Seiringer, Robert and Solovej, Jan}, journal = {Communications in Mathematical Physics}, number = {1}, pages = {189 -- 216}, publisher = {Springer}, title = {{The external field dependence of the BCS critical temperature}}, doi = {10.1007/s00220-015-2526-2}, volume = {342}, year = {2016}, } @article{1622, abstract = {We prove analogues of the Lieb–Thirring and Hardy–Lieb–Thirring inequalities for many-body quantum systems with fractional kinetic operators and homogeneous interaction potentials, where no anti-symmetry on the wave functions is assumed. These many-body inequalities imply interesting one-body interpolation inequalities, and we show that the corresponding one- and many-body inequalities are actually equivalent in certain cases.}, author = {Lundholm, Douglas and Nam, Phan and Portmann, Fabian}, journal = {Archive for Rational Mechanics and Analysis}, number = {3}, pages = {1343 -- 1382}, publisher = {Springer}, title = {{Fractional Hardy–Lieb–Thirring and related Inequalities for interacting systems}}, doi = {10.1007/s00205-015-0923-5}, volume = {219}, year = {2016}, } @article{1631, abstract = {Ancestral processes are fundamental to modern population genetics and spatial structure has been the subject of intense interest for many years. Despite this interest, almost nothing is known about the distribution of the locations of pedigree or genetic ancestors. Using both spatially continuous and stepping-stone models, we show that the distribution of pedigree ancestors approaches a travelling wave, for which we develop two alternative approximations. The speed and width of the wave are sensitive to the local details of the model. After a short time, genetic ancestors spread far more slowly than pedigree ancestors, ultimately diffusing out with radius ## rather than spreading at constant speed. In contrast to the wave of pedigree ancestors, the spread of genetic ancestry is insensitive to the local details of the models.}, author = {Kelleher, Jerome and Etheridge, Alison and Véber, Amandine and Barton, Nicholas H}, journal = {Theoretical Population Biology}, pages = {1 -- 12}, publisher = {Academic Press}, title = {{Spread of pedigree versus genetic ancestry in spatially distributed populations}}, doi = {10.1016/j.tpb.2015.10.008}, volume = {108}, year = {2016}, } @article{1641, abstract = {The plant hormone auxin (indole-3-acetic acid) is a major regulator of plant growth and development including embryo and root patterning, lateral organ formation and growth responses to environmental stimuli. Auxin is directionally transported from cell to cell by the action of specific auxin influx [AUXIN-RESISTANT1 (AUX1)] and efflux [PIN-FORMED (PIN)] transport regulators, whose polar, subcellular localizations are aligned with the direction of the auxin flow. Auxin itself regulates its own transport by modulation of the expression and subcellular localization of the auxin transporters. Increased auxin levels promote the transcription of PIN2 and AUX1 genes as well as stabilize PIN proteins at the plasma membrane, whereas prolonged auxin exposure increases the turnover of PIN proteins and their degradation in the vacuole. In this study, we applied a forward genetic approach, to identify molecular components playing a role in the auxin-mediated degradation. We generated EMS-mutagenized Arabidopsis PIN2::PIN2:GFP, AUX1::AUX1:YFP eir1aux1 populations and designed a screen for mutants with persistently strong fluorescent signals of the tagged PIN2 and AUX1 after prolonged treatment with the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D). This approach yielded novel auxin degradation mutants defective in trafficking and degradation of PIN2 and AUX1 proteins and established a role for auxin-mediated degradation in plant development.}, author = {Zemová, Radka and Zwiewka, Marta and Bielach, Agnieszka and Robert, Hélène and Friml, Jirí}, journal = {Journal of Plant Growth Regulation}, number = {2}, pages = {465 -- 476}, publisher = {Springer}, title = {{A forward genetic screen for new regulators of auxin mediated degradation of auxin transport proteins in Arabidopsis thaliana}}, doi = {10.1007/s00344-015-9553-2}, volume = {35}, year = {2016}, } @inproceedings{1653, abstract = {A somewhere statistically binding (SSB) hash, introduced by Hubáček and Wichs (ITCS ’15), can be used to hash a long string x to a short digest y = H hk (x) using a public hashing-key hk. Furthermore, there is a way to set up the hash key hk to make it statistically binding on some arbitrary hidden position i, meaning that: (1) the digest y completely determines the i’th bit (or symbol) of x so that all pre-images of y have the same value in the i’th position, (2) it is computationally infeasible to distinguish the position i on which hk is statistically binding from any other position i’. Lastly, the hash should have a local opening property analogous to Merkle-Tree hashing, meaning that given x and y = H hk (x) it should be possible to create a short proof π that certifies the value of the i’th bit (or symbol) of x without having to provide the entire input x. A similar primitive called a positional accumulator, introduced by Koppula, Lewko and Waters (STOC ’15) further supports dynamic updates of the hashed value. These tools, which are interesting in their own right, also serve as one of the main technical components in several recent works building advanced applications from indistinguishability obfuscation (iO). The prior constructions of SSB hashing and positional accumulators required fully homomorphic encryption (FHE) and iO respectively. In this work, we give new constructions of these tools based on well studied number-theoretic assumptions such as DDH, Phi-Hiding and DCR, as well as a general construction from lossy/injective functions.}, author = {Okamoto, Tatsuaki and Pietrzak, Krzysztof Z and Waters, Brent and Wichs, Daniel}, location = {Auckland, New Zealand}, pages = {121 -- 145}, publisher = {Springer}, title = {{New realizations of somewhere statistically binding hashing and positional accumulators}}, doi = {10.1007/978-3-662-48797-6_6}, volume = {9452}, year = {2016}, } @article{1705, abstract = {Hybrid systems represent an important and powerful formalism for modeling real-world applications such as embedded systems. A verification tool like SpaceEx is based on the exploration of a symbolic search space (the region space). As a verification tool, it is typically optimized towards proving the absence of errors. In some settings, e.g., when the verification tool is employed in a feedback-directed design cycle, one would like to have the option to call a version that is optimized towards finding an error trajectory in the region space. A recent approach in this direction is based on guided search. Guided search relies on a cost function that indicates which states are promising to be explored, and preferably explores more promising states first. In this paper, we propose an abstraction-based cost function based on coarse-grained space abstractions for guiding the reachability analysis. For this purpose, a suitable abstraction technique that exploits the flexible granularity of modern reachability analysis algorithms is introduced. The new cost function is an effective extension of pattern database approaches that have been successfully applied in other areas. The approach has been implemented in the SpaceEx model checker. The evaluation shows its practical potential.}, author = {Bogomolov, Sergiy and Donzé, Alexandre and Frehse, Goran and Grosu, Radu and Johnson, Taylor and Ladan, Hamed and Podelski, Andreas and Wehrle, Martin}, journal = {International Journal on Software Tools for Technology Transfer}, number = {4}, pages = {449 -- 467}, publisher = {Springer}, title = {{Guided search for hybrid systems based on coarse-grained space abstractions}}, doi = {10.1007/s10009-015-0393-y}, volume = {18}, year = {2016}, } @inproceedings{1707, abstract = {Volunteer supporters play an important role in modern crisis and disaster management. In the times of mobile Internet devices, help from thousands of volunteers can be requested within a short time span, thus relieving professional helpers from minor chores or geographically spread-out tasks. However, the simultaneous availability of many volunteers also poses new problems. In particular, the volunteer efforts must be well coordinated, or otherwise situations might emerge in which too many idle volunteers at one location become more of a burden than a relief to the professionals. In this work, we study the task of optimally assigning volunteers to selected locations, e.g. in order to perform regular measurements, to report on damage, or to distribute information or resources to the population in a crisis situation. We formulate the assignment tasks as an optimization problem and propose an effective and efficient solution procedure. Experiments on real data of the Team Österreich, consisting of over 36,000 Austrian volunteers, show the effectiveness and efficiency of our approach.}, author = {Pielorz, Jasmin and Lampert, Christoph}, location = {Rennes, France}, publisher = {IEEE}, title = {{Optimal geospatial allocation of volunteers for crisis management}}, doi = {10.1109/ICT-DM.2015.7402041}, year = {2016}, } @article{1881, abstract = {We consider random matrices of the form H=W+λV, λ∈ℝ+, where W is a real symmetric or complex Hermitian Wigner matrix of size N and V is a real bounded diagonal random matrix of size N with i.i.d.\ entries that are independent of W. We assume subexponential decay for the matrix entries of W and we choose λ∼1, so that the eigenvalues of W and λV are typically of the same order. Further, we assume that the density of the entries of V is supported on a single interval and is convex near the edges of its support. In this paper we prove that there is λ+∈ℝ+ such that the largest eigenvalues of H are in the limit of large N determined by the order statistics of V for λ>λ+. In particular, the largest eigenvalue of H has a Weibull distribution in the limit N→∞ if λ>λ+. Moreover, for N sufficiently large, we show that the eigenvectors associated to the largest eigenvalues are partially localized for λ>λ+, while they are completely delocalized for λ<λ+. Similar results hold for the lowest eigenvalues. }, author = {Lee, Jioon and Schnelli, Kevin}, journal = {Probability Theory and Related Fields}, number = {1-2}, pages = {165 -- 241}, publisher = {Springer}, title = {{Extremal eigenvalues and eigenvectors of deformed Wigner matrices}}, doi = {10.1007/s00440-014-0610-8}, volume = {164}, year = {2016}, } @inproceedings{478, abstract = {Magic: the Gathering is a game about magical combat for any number of players. Formally it is a zero-sum, imperfect information stochastic game that consists of a potentially unbounded number of steps. We consider the problem of deciding if a move is legal in a given single step of Magic. We show that the problem is (a) coNP-complete in general; and (b) in P if either of two small sets of cards are not used. Our lower bound holds even for single-player Magic games. The significant aspects of our results are as follows: First, in most real-life game problems, the task of deciding whether a given move is legal in a single step is trivial, and the computationally hard task is to find the best sequence of legal moves in the presence of multiple players. In contrast, quite uniquely our hardness result holds for single step and with only one-player. Second, we establish efficient algorithms for important special cases of Magic.}, author = {Chatterjee, Krishnendu and Ibsen-Jensen, Rasmus}, location = {The Hague, Netherlands}, pages = {1432 -- 1439}, publisher = {IOS Press}, title = {{The complexity of deciding legality of a single step of magic: The gathering}}, doi = {10.3233/978-1-61499-672-9-1432}, volume = {285}, year = {2016}, } @inproceedings{479, abstract = {Clinical guidelines and decision support systems (DSS) play an important role in daily practices of medicine. Many text-based guidelines have been encoded for work-flow simulation of DSS to automate health care. During the collaboration with Carle hospital to develop a DSS, we identify that, for some complex and life-critical diseases, it is highly desirable to automatically rigorously verify some complex temporal properties in guidelines, which brings new challenges to current simulation based DSS with limited support of automatical formal verification and real-time data analysis. In this paper, we conduct the first study on applying runtime verification to cooperate with current DSS based on real-time data. Within the proposed technique, a user-friendly domain specific language, named DRTV, is designed to specify vital real-time data sampled by medical devices and temporal properties originated from clinical guidelines. Some interfaces are developed for data acquisition and communication. Then, for medical practice scenarios described in DRTV model, we will automatically generate event sequences and runtime property verifier automata. If a temporal property violates, real-time warnings will be produced by the formal verifier and passed to medical DSS. We have used DRTV to specify different kinds of medical care scenarios, and applied the proposed technique to assist existing DSS. As presented in experiment results, in terms of warning detection, it outperforms the only use of DSS or human inspection, and improves the quality of clinical health care of hospital}, author = {Jiang, Yu and Liu, Han and Kong, Hui and Wang, Rui and Hosseini, Mohamad and Sun, Jiaguang and Sha, Lui}, booktitle = {Proceedings of the 38th International Conference on Software Engineering Companion }, location = {Austin, TX, USA}, pages = {112 -- 121}, publisher = {IEEE}, title = {{Use runtime verification to improve the quality of medical care practice}}, doi = {10.1145/2889160.2889233}, year = {2016}, } @inproceedings{480, abstract = {Graph games provide the foundation for modeling and synthesizing reactive processes. In the synthesis of stochastic reactive processes, the traditional model is perfect-information stochastic games, where some transitions of the game graph are controlled by two adversarial players, and the other transitions are executed probabilistically. We consider such games where the objective is the conjunction of several quantitative objectives (specified as mean-payoff conditions), which we refer to as generalized mean-payoff objectives. The basic decision problem asks for the existence of a finite-memory strategy for a player that ensures the generalized mean-payoff objective be satisfied with a desired probability against all strategies of the opponent. A special case of the decision problem is the almost-sure problem where the desired probability is 1. Previous results presented a semi-decision procedure for -approximations of the almost-sure problem. In this work, we show that both the almost-sure problem as well as the general basic decision problem are coNP-complete, significantly improving the previous results. Moreover, we show that in the case of 1-player stochastic games, randomized memoryless strategies are sufficient and the problem can be solved in polynomial time. In contrast, in two-player stochastic games, we show that even with randomized strategies exponential memory is required in general, and present a matching exponential upper bound. We also study the basic decision problem with infinite-memory strategies and present computational complexity results for the problem. Our results are relevant in the synthesis of stochastic reactive systems with multiple quantitative requirements.}, author = {Chatterjee, Krishnendu and Doyen, Laurent}, location = {New York, NY, USA}, pages = {247 -- 256}, publisher = {IEEE}, title = {{Perfect-information stochastic games with generalized mean-payoff objectives}}, doi = {10.1145/2933575.2934513}, volume = {05-08-July-2016}, year = {2016}, } @inproceedings{482, abstract = {Nonlinear electro-optical conversion of microwave radiation into the optical telecommunication band is achieved within a crystalline whispering gallery mode resonator, reaching 0.1% photon number conversion efficiency with MHz bandwidth.}, author = {Rueda, Alfredo and Sedlmeir, Florian and Collodo, Michele and Vogl, Ulrich and Stiller, Birgit and Schunk, Gerhard and Strekalov, Dmitry and Marquardt, Christoph and Fink, Johannes M and Painter, Oskar and Leuchs, Gerd and Schwefel, Harald}, location = {Sydney, Australia}, publisher = {Optica Publishing Group}, title = {{Nonlinear single sideband microwave to optical conversion using an electro-optic WGM-resonator}}, doi = {10.1364/NP.2016.NTh3A.6}, year = {2016}, } @article{510, abstract = {The CLE (CLAVATA3/Embryo Surrounding Region-related) peptides are small secreted signaling peptides that are primarily involved in the regulation of stem cell homeostasis in different plant meristems. Particularly, the characterization of the CLE41-PXY/TDR signaling pathway has greatly advanced our understanding on the potential roles of CLE peptides in vascular development and wood formation. Nevertheless, our knowledge on this gene family in a tree species is limited. In a recent study, we reported on a systematically investigation of the CLE gene family in Populus trichocarpa . The potential roles of PtCLE genes were studied by comparative analysis and transcriptional pro fi ling. Among fi fty PtCLE members, many PtCLE proteins share identical CLE motifs or contain the same CLE motif as that of AtCLEs, while PtCLE genes exhibited either comparable or distinct expression patterns comparing to their Arabidopsis counterparts. These fi ndings indicate the existence of both functional conservation and functional divergence between PtCLEs and their AtCLE orthologues. Our results provide valuable resources for future functional investigations of these critical signaling molecules in woody plants. }, author = {Liu, Zhijun and Yang, Nan and Lv, Yanting and Pan, Lixia and Lv, Shuo and Han, Huibin and Wang, Guodong}, journal = {Plant Signaling & Behavior}, number = {6}, publisher = {Taylor & Francis}, title = {{The CLE gene family in Populus trichocarpa}}, doi = {10.1080/15592324.2016.1191734}, volume = {11}, year = {2016}, } @misc{5445, abstract = {We consider the quantitative analysis problem for interprocedural control-flow graphs (ICFGs). The input consists of an ICFG, a positive weight function that assigns every transition a positive integer-valued number, and a labelling of the transitions (events) as good, bad, and neutral events. The weight function assigns to each transition a numerical value that represents ameasure of how good or bad an event is. The quantitative analysis problem asks whether there is a run of the ICFG where the ratio of the sum of the numerical weights of good events versus the sum of weights of bad events in the long-run is at least a given threshold (or equivalently, to compute the maximal ratio among all valid paths in the ICFG). The quantitative analysis problem for ICFGs can be solved in polynomial time, and we present an efficient and practical algorithm for the problem. We show that several problems relevant for static program analysis, such as estimating the worst-case execution time of a program or the average energy consumption of a mobile application, can be modeled in our framework. We have implemented our algorithm as a tool in the Java Soot framework. We demonstrate the effectiveness of our approach with two case studies. First, we show that our framework provides a sound approach (no false positives) for the analysis of inefficiently-used containers. Second, we show that our approach can also be used for static profiling of programs which reasons about methods that are frequently invoked. Our experimental results show that our tool scales to relatively large benchmarks, and discovers relevant and useful information that can be used to optimize performance of the programs. }, author = {Chatterjee, Krishnendu and Pavlogiannis, Andreas and Velner, Yaron}, issn = {2664-1690}, pages = {33}, publisher = {IST Austria}, title = {{Quantitative interprocedural analysis}}, doi = {10.15479/AT:IST-2016-523-v1-1}, year = {2016}, } @misc{5446, abstract = {We study the problem of developing efficient approaches for proving termination of recursive programs with one-dimensional arrays. Ranking functions serve as a sound and complete approach for proving termination of non-recursive programs without array operations. First, we generalize ranking functions to the notion of measure functions, and prove that measure functions (i) provide a sound method to prove termination of recursive programs (with one-dimensional arrays), and (ii) is both sound and complete over recursive programs without array operations. Our second contribution is the synthesis of measure functions of specific forms in polynomial time. More precisely, we prove that (i) polynomial measure functions over recursive programs can be synthesized in polynomial time through Farkas’ Lemma and Handelman’s Theorem, and (ii) measure functions involving logarithm and exponentiation can be synthesized in polynomial time through abstraction of logarithmic or exponential terms and Handelman’s Theorem. A key application of our method is the worst-case analysis of recursive programs. While previous methods obtain worst-case polynomial bounds of the form O(n^k), where k is an integer, our polynomial time methods can synthesize bounds of the form O(n log n), as well as O(n^x), where x is not an integer. We show the applicability of our automated technique to obtain worst-case complexity of classical recursive algorithms such as (i) Merge-Sort, the divideand- conquer algorithm for the Closest-Pair problem, where we obtain O(n log n) worst-case bound, and (ii) Karatsuba’s algorithm for polynomial multiplication and Strassen’s algorithm for matrix multiplication, where we obtain O(n^x) bound, where x is not an integer and close to the best-known bounds for the respective algorithms. Finally, we present experimental results to demonstrate the effectiveness of our approach.}, author = {Anonymous, 1 and Anonymous, 2 and Anonymous, 3}, issn = {2664-1690}, pages = {26}, publisher = {IST Austria}, title = {{Termination and worst-case analysis of recursive programs}}, year = {2016}, } @misc{5447, abstract = {We consider the problem of developing automated techniques to aid the average-case complexity analysis of programs. Several classical textbook algorithms have quite efficient average-case complexity, whereas the corresponding worst-case bounds are either inefficient (e.g., QUICK-SORT), or completely ineffective (e.g., COUPONCOLLECTOR). Since the main focus of average-case analysis is to obtain efficient bounds, we consider bounds that are either logarithmic, linear, or almost-linear (O(log n), O(n), O(n · log n), respectively, where n represents the size of the input). Our main contribution is a sound approach for deriving such average-case bounds for randomized recursive programs. Our approach is efficient (a simple linear-time algorithm), and it is based on (a) the analysis of recurrence relations induced by randomized algorithms, and (b) a guess-and-check technique. Our approach can infer the asymptotically optimal average-case bounds for classical randomized algorithms, including RANDOMIZED-SEARCH, QUICKSORT, QUICK-SELECT, COUPON-COLLECTOR, where the worstcase bounds are either inefficient (such as linear as compared to logarithmic of average-case, or quadratic as compared to linear or almost-linear of average-case), or ineffective. We have implemented our approach, and the experimental results show that we obtain the bounds efficiently for various classical algorithms.}, author = {Anonymous, 1 and Anonymous, 2 and Anonymous, 3}, issn = {2664-1690}, pages = {20}, publisher = {IST Austria}, title = {{Average-case analysis of programs: Automated recurrence analysis for almost-linear bounds}}, year = {2016}, } @misc{5448, abstract = {We present a new dynamic partial-order reduction method for stateless model checking of concurrent programs. A common approach for exploring program behaviors relies on enumerating the traces of the program, without storing the visited states (aka stateless exploration). As the number of distinct traces grows exponentially, dynamic partial-order reduction (DPOR) techniques have been successfully used to partition the space of traces into equivalence classes (Mazurkiewicz partitioning), with the goal of exploring only few representative traces from each class. We introduce a new equivalence on traces under sequential consistency semantics, which we call the observation equivalence. Two traces are observationally equivalent if every read event observes the same write event in both traces. While the traditional Mazurkiewicz equivalence is control-centric, our new definition is data-centric. We show that our observation equivalence is coarser than the Mazurkiewicz equivalence, and in many cases even exponentially coarser. We devise a DPOR exploration of the trace space, called data-centric DPOR, based on the observation equivalence. 1. For acyclic architectures, our algorithm is guaranteed to explore exactly one representative trace from each observation class, while spending polynomial time per class. Hence, our algorithm is optimal wrt the observation equivalence, and in several cases explores exponentially fewer traces than any enumerative method based on the Mazurkiewicz equivalence. 2. For cyclic architectures, we consider an equivalence between traces which is finer than the observation equivalence; but coarser than the Mazurkiewicz equivalence, and in some cases is exponentially coarser. Our data-centric DPOR algorithm remains optimal under this trace equivalence. Finally, we perform a basic experimental comparison between the existing Mazurkiewicz-based DPOR and our data-centric DPOR on a set of academic benchmarks. Our results show a significant reduction in both running time and the number of explored equivalence classes.}, author = {Anonymous, 1 and Anonymous, 2 and Anonymous, 3 and Anonymous, 4}, issn = {2664-1690}, pages = {20}, publisher = {IST Austria}, title = {{Data-centric dynamic partial order reduction}}, year = {2016}, } @misc{5449, abstract = {The fixation probability is the probability that a new mutant introduced in a homogeneous population eventually takes over the entire population. The fixation probability is a fundamental quantity of natural selection, and known to depend on the population structure. Amplifiers of natural selection are population structures which increase the fixation probability of advantageous mutants, as compared to the baseline case of well-mixed populations. In this work we focus on symmetric population structures represented as undirected graphs. In the regime of undirected graphs, the strongest amplifier known has been the Star graph, and the existence of undirected graphs with stronger amplification properties has remained open for over a decade. In this work we present the Comet and Comet-swarm families of undirected graphs. We show that for a range of fitness values of the mutants, the Comet and Comet-swarm graphs have fixation probability strictly larger than the fixation probability of the Star graph, for fixed population size and at the limit of large populations, respectively.}, author = {Pavlogiannis, Andreas and Tkadlec, Josef and Chatterjee, Krishnendu and Nowak, Martin}, issn = {2664-1690}, pages = {22}, publisher = {IST Austria}, title = {{Amplification on undirected population structures: Comets beat stars}}, doi = {10.15479/AT:IST-2016-648-v1-1}, year = {2016}, }