@article{5982, abstract = {In the present work, we detail a fast and simple solution-based method to synthesize hexagonal SnSe2 nanoplates (NPLs) and their use to produce crystallographically textured SnSe2 nanomaterials. We also demonstrate that the same strategy can be used to produce orthorhombic SnSe nanostructures and nanomaterials. NPLs are grown through a screw dislocation-driven mechanism. This mechanism typically results in pyramidal structures, but we demonstrate here that the growth from multiple dislocations results in flower-like structures. Crystallographically textured SnSe2 bulk nanomaterials obtained from the hot pressing of these SnSe2 structures display highly anisotropic charge and heat transport properties and thermoelectric (TE) figures of merit limited by relatively low electrical conductivities. To improve this parameter, SnSe2 NPLs are blended here with metal nanoparticles. The electrical conductivities of the blends are significantly improved with respect to bare SnSe2 NPLs, what translates into a three-fold increase of the TE Figure of merit, reaching unprecedented ZT values up to 0.65.}, author = {Zhang, Yu and Liu, Yu and Lim, Khak Ho and Xing, Congcong and Li, Mengyao and Zhang, Ting and Tang, Pengyi and Arbiol, Jordi and Llorca, Jordi and Ng, Ka Ming and Ibáñez, Maria and Guardia, Pablo and Prato, Mirko and Cadavid, Doris and Cabot, Andreu}, issn = {1433-7851}, journal = {Angewandte Chemie International Edition}, number = {52}, pages = {17063--17068}, publisher = {Wiley}, title = {{Tin diselenide molecular precursor for solution-processable thermoelectric materials}}, doi = {10.1002/anie.201809847}, volume = {57}, year = {2018}, } @inproceedings{5978, abstract = {We consider the MAP-inference problem for graphical models,which is a valued constraint satisfaction problem defined onreal numbers with a natural summation operation. We proposea family of relaxations (different from the famous Sherali-Adams hierarchy), which naturally define lower bounds for itsoptimum. This family always contains a tight relaxation andwe give an algorithm able to find it and therefore, solve theinitial non-relaxed NP-hard problem.The relaxations we consider decompose the original probleminto two non-overlapping parts: an easy LP-tight part and adifficult one. For the latter part a combinatorial solver must beused. As we show in our experiments, in a number of applica-tions the second, difficult part constitutes only a small fractionof the whole problem. This property allows to significantlyreduce the computational time of the combinatorial solver andtherefore solve problems which were out of reach before.}, author = {Haller, Stefan and Swoboda, Paul and Savchynskyy, Bogdan}, booktitle = {Proceedings of the 32st AAAI Conference on Artificial Intelligence}, location = {New Orleans, LU, United States}, pages = {6581--6588}, publisher = {AAAI Press}, title = {{Exact MAP-inference by confining combinatorial search with LP relaxation}}, year = {2018}, } @article{5990, abstract = {A Ge–Si core–shell nanowire is used to realize a Josephson field‐effect transistor with highly transparent contacts to superconducting leads. By changing the electric field, access to two distinct regimes, not combined before in a single device, is gained: in the accumulation mode the device is highly transparent and the supercurrent is carried by multiple subbands, while near depletion, the supercurrent is carried by single‐particle levels of a strongly coupled quantum dot operating in the few‐hole regime. These results establish Ge–Si nanowires as an important platform for hybrid superconductor–semiconductor physics and Majorana fermions.}, author = {Ridderbos, Joost and Brauns, Matthias and Shen, Jie and de Vries, Folkert K. and Li, Ang and Bakkers, Erik P. A. M. and Brinkman, Alexander and Zwanenburg, Floris A.}, issn = {0935-9648}, journal = {Advanced Materials}, number = {44}, publisher = {Wiley}, title = {{Josephson effect in a few-hole quantum dot}}, doi = {10.1002/adma.201802257}, volume = {30}, year = {2018}, } @article{5980, abstract = {The problem of private set-intersection (PSI) has been traditionally treated as an instance of the more general problem of multi-party computation (MPC). Consequently, in order to argue security, or compose these protocols one has to rely on the general theory that was developed for the purpose of MPC. The pursuit of efficient protocols, however, has resulted in designs that exploit properties pertaining to PSI. In almost all practical applications where a PSI protocol is deployed, it is expected to be executed multiple times, possibly on related inputs. In this work we initiate a dedicated study of PSI in the multi-interaction (MI) setting. In this model a server sets up the common system parameters and executes set-intersection multiple times with potentially different clients. We discuss a few attacks that arise when protocols are naïvely composed in this manner and, accordingly, craft security definitions for the MI setting and study their inter-relation. Finally, we suggest a set of protocols that are MI-secure, at the same time almost as efficient as their parent, stand-alone, protocols.}, author = {Chatterjee, Sanjit and Kamath Hosdurg, Chethan and Kumar, Vikas}, journal = {American Institute of Mathematical Sciences}, number = {1}, pages = {17--47}, publisher = {AIMS}, title = {{Private set-intersection with common set-up}}, doi = {10.3934/amc.2018002}, volume = {12}, year = {2018}, } @article{5998, abstract = {Genome amplification and cellular senescence are commonly associated with pathological processes. While physiological roles for polyploidization and senescence have been described in mouse development, controversy exists over their significance in humans. Here, we describe tetraploidization and senescence as phenomena of normal human placenta development. During pregnancy, placental extravillous trophoblasts (EVTs) invade the pregnant endometrium, termed decidua, to establish an adapted microenvironment required for the developing embryo. This process is critically dependent on continuous cell proliferation and differentiation, which is thought to follow the classical model of cell cycle arrest prior to terminal differentiation. Strikingly, flow cytometry and DNAseq revealed that EVT formation is accompanied with a genome-wide polyploidization, independent of mitotic cycles. DNA replication in these cells was analysed by a fluorescent cell-cycle indicator reporter system, cell cycle marker expression and EdU incorporation. Upon invasion into the decidua, EVTs widely lose their replicative potential and enter a senescent state characterized by high senescence-associated (SA) β-galactosidase activity, induction of a SA secretory phenotype as well as typical metabolic alterations. Furthermore, we show that the shift from endocycle-dependent genome amplification to growth arrest is disturbed in androgenic complete hydatidiform moles (CHM), a hyperplastic pregnancy disorder associated with increased risk of developing choriocarinoma. Senescence is decreased in CHM-EVTs, accompanied by exacerbated endoreduplication and hyperploidy. We propose induction of cellular senescence as a ploidy-limiting mechanism during normal human placentation and unravel a link between excessive polyploidization and reduced senescence in CHM.}, author = {Velicky, Philipp and Meinhardt, Gudrun and Plessl, Kerstin and Vondra, Sigrid and Weiss, Tamara and Haslinger, Peter and Lendl, Thomas and Aumayr, Karin and Mairhofer, Mario and Zhu, Xiaowei and Schütz, Birgit and Hannibal, Roberta L. and Lindau, Robert and Weil, Beatrix and Ernerudh, Jan and Neesen, Jürgen and Egger, Gerda and Mikula, Mario and Röhrl, Clemens and Urban, Alexander E. and Baker, Julie and Knöfler, Martin and Pollheimer, Jürgen}, issn = {1553-7404}, journal = {PLOS Genetics}, number = {10}, publisher = {Public Library of Science}, title = {{Genome amplification and cellular senescence are hallmarks of human placenta development}}, doi = {10.1371/journal.pgen.1007698}, volume = {14}, year = {2018}, } @article{5995, abstract = {Motivation Computational prediction of the effect of mutations on protein stability is used by researchers in many fields. The utility of the prediction methods is affected by their accuracy and bias. Bias, a systematic shift of the predicted change of stability, has been noted as an issue for several methods, but has not been investigated systematically. Presence of the bias may lead to misleading results especially when exploring the effects of combination of different mutations. Results Here we use a protocol to measure the bias as a function of the number of introduced mutations. It is based on a self-consistency test of the reciprocity the effect of a mutation. An advantage of the used approach is that it relies solely on crystal structures without experimentally measured stability values. We applied the protocol to four popular algorithms predicting change of protein stability upon mutation, FoldX, Eris, Rosetta and I-Mutant, and found an inherent bias. For one program, FoldX, we manage to substantially reduce the bias using additional relaxation by Modeller. Authors using algorithms for predicting effects of mutations should be aware of the bias described here.}, author = {Usmanova, Dinara R and Bogatyreva, Natalya S and Ariño Bernad, Joan and Eremina, Aleksandra A and Gorshkova, Anastasiya A and Kanevskiy, German M and Lonishin, Lyubov R and Meister, Alexander V and Yakupova, Alisa G and Kondrashov, Fyodor and Ivankov, Dmitry}, issn = {1367-4803}, journal = {Bioinformatics}, number = {21}, pages = {3653--3658}, publisher = {Oxford University Press }, title = {{Self-consistency test reveals systematic bias in programs for prediction change of stability upon mutation}}, doi = {10.1093/bioinformatics/bty340}, volume = {34}, year = {2018}, } @article{5992, abstract = {Lamellipodia are flat membrane protrusions formed during mesenchymal motion. Polymerization at the leading edge assembles the actin filament network and generates protrusion force. How this force is supported by the network and how the assembly rate is shared between protrusion and network retrograde flow determines the protrusion rate. We use mathematical modeling to understand experiments changing the F-actin density in lamellipodia of B16-F1 melanoma cells by modulation of Arp2/3 complex activity or knockout of the formins FMNL2 and FMNL3. Cells respond to a reduction of density with a decrease of protrusion velocity, an increase in the ratio of force to filament number, but constant network assembly rate. The relation between protrusion force and tension gradient in the F-actin network and the density dependency of friction, elasticity, and viscosity of the network explain the experimental observations. The formins act as filament nucleators and elongators with differential rates. Modulation of their activity suggests an effect on network assembly rate. Contrary to these expectations, the effect of changes in elongator composition is much weaker than the consequences of the density change. We conclude that the force acting on the leading edge membrane is the force required to drive F-actin network retrograde flow.}, author = {Dolati, Setareh and Kage, Frieda and Mueller, Jan and Müsken, Mathias and Kirchner, Marieluise and Dittmar, Gunnar and Sixt, Michael K and Rottner, Klemens and Falcke, Martin}, issn = {1939-4586}, journal = {Molecular Biology of the Cell}, number = {22}, pages = {2674--2686}, publisher = {American Society for Cell Biology }, title = {{On the relation between filament density, force generation, and protrusion rate in mesenchymal cell motility}}, doi = {10.1091/mbc.e18-02-0082}, volume = {29}, year = {2018}, } @article{6010, abstract = {The optic tectum (TeO), or superior colliculus, is a multisensory midbrain center that organizes spatially orienting responses to relevant stimuli. To define the stimulus with the highest priority at each moment, a network of reciprocal connections between the TeO and the isthmi promotes competition between concurrent tectal inputs. In the avian midbrain, the neurons mediating enhancement and suppression of tectal inputs are located in separate isthmic nuclei, facilitating the analysis of the neural processes that mediate competition. A specific subset of radial neurons in the intermediate tectal layers relay retinal inputs to the isthmi, but at present it is unclear whether separate neurons innervate individual nuclei or a single neural type sends a common input to several of them. In this study, we used in vitro neural tracing and cell-filling experiments in chickens to show that single neurons innervate, via axon collaterals, the three nuclei that comprise the isthmotectal network. This demonstrates that the input signals representing the strength of the incoming stimuli are simultaneously relayed to the mechanisms promoting both enhancement and suppression of the input signals. By performing in vivo recordings in anesthetized chicks, we also show that this common input generates synchrony between both antagonistic mechanisms, demonstrating that activity enhancement and suppression are closely coordinated. From a computational point of view, these results suggest that these tectal neurons constitute integrative nodes that combine inputs from different sources to drive in parallel several concurrent neural processes, each performing complementary functions within the network through different firing patterns and connectivity.}, author = {Garrido-Charad, Florencia and Vega Zuniga, Tomas A and Gutiérrez-Ibáñez, Cristián and Fernandez, Pedro and López-Jury, Luciana and González-Cabrera, Cristian and Karten, Harvey J. and Luksch, Harald and Marín, Gonzalo J.}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {32}, pages = {E7615--E7623}, publisher = {National Academy of Sciences}, title = {{“Shepherd’s crook” neurons drive and synchronize the enhancing and suppressive mechanisms of the midbrain stimulus selection network}}, doi = {10.1073/pnas.1804517115}, volume = {115}, year = {2018}, } @article{6003, abstract = {Digital fabrication devices are powerful tools for creating tangible reproductions of 3D digital models. Most available printing technologies aim at producing an accurate copy of a tridimensional shape. However, fabrication technologies can also be used to create a stylistic representation of a digital shape. We refer to this class of methods as ‘stylized fabrication methods’. These methods abstract geometric and physical features of a given shape to create an unconventional representation, to produce an optical illusion or to devise a particular interaction with the fabricated model. In this state‐of‐the‐art report, we classify and overview this broad and emerging class of approaches and also propose possible directions for future research.}, author = {Bickel, Bernd and Cignoni, Paolo and Malomo, Luigi and Pietroni, Nico}, issn = {0167-7055}, journal = {Computer Graphics Forum}, number = {6}, pages = {325--342}, publisher = {Wiley}, title = {{State of the art on stylized fabrication}}, doi = {10.1111/cgf.13327}, volume = {37}, year = {2018}, } @article{6002, abstract = {The Bogoliubov free energy functional is analysed. The functional serves as a model of a translation-invariant Bose gas at positive temperature. We prove the existence of minimizers in the case of repulsive interactions given by a sufficiently regular two-body potential. Furthermore, we prove the existence of a phase transition in this model and provide its phase diagram.}, author = {Napiórkowski, Marcin M and Reuvers, Robin and Solovej, Jan Philip}, issn = {1432-0673}, journal = {Archive for Rational Mechanics and Analysis}, number = {3}, pages = {1037--1090}, publisher = {Springer Nature}, title = {{The Bogoliubov free energy functional I: Existence of minimizers and phase diagram}}, doi = {10.1007/s00205-018-1232-6}, volume = {229}, year = {2018}, } @article{5996, abstract = {In pipes, turbulence sets in despite the linear stability of the laminar Hagen–Poiseuille flow. The Reynolds number ( ) for which turbulence first appears in a given experiment – the ‘natural transition point’ – depends on imperfections of the set-up, or, more precisely, on the magnitude of finite amplitude perturbations. At onset, turbulence typically only occupies a certain fraction of the flow, and this fraction equally is found to differ from experiment to experiment. Despite these findings, Reynolds proposed that after sufficiently long times, flows may settle to steady conditions: below a critical velocity, flows should (regardless of initial conditions) always return to laminar, while above this velocity, eddying motion should persist. As will be shown, even in pipes several thousand diameters long, the spatio-temporal intermittent flow patterns observed at the end of the pipe strongly depend on the initial conditions, and there is no indication that different flow patterns would eventually settle to a (statistical) steady state. Exploiting the fact that turbulent puffs do not age (i.e. they are memoryless), we continuously recreate the puff sequence exiting the pipe at the pipe entrance, and in doing so introduce periodic boundary conditions for the puff pattern. This procedure allows us to study the evolution of the flow patterns for arbitrary long times, and we find that after times in excess of advective time units, indeed a statistical steady state is reached. Although the resulting flows remain spatio-temporally intermittent, puff splitting and decay rates eventually reach a balance, so that the turbulent fraction fluctuates around a well-defined level which only depends on . In accordance with Reynolds’ proposition, we find that at lower (here 2020), flows eventually always resume to laminar, while for higher ( ), turbulence persists. The critical point for pipe flow hence falls in the interval of $2020 , which is in very good agreement with the recently proposed value of . The latter estimate was based on single-puff statistics and entirely neglected puff interactions. Unlike in typical contact processes where such interactions strongly affect the percolation threshold, in pipe flow, the critical point is only marginally influenced. Interactions, on the other hand, are responsible for the approach to the statistical steady state. As shown, they strongly affect the resulting flow patterns, where they cause ‘puff clustering’, and these regions of large puff densities are observed to travel across the puff pattern in a wave-like fashion.}, author = {Vasudevan, Mukund and Hof, Björn}, issn = {1469-7645}, journal = {Journal of Fluid Mechanics}, pages = {76--94}, publisher = {Cambridge University Press}, title = {{The critical point of the transition to turbulence in pipe flow}}, doi = {10.1017/jfm.2017.923}, volume = {839}, year = {2018}, } @article{5993, abstract = {In this article, we consider the termination problem of probabilistic programs with real-valued variables. Thequestions concerned are: qualitative ones that ask (i) whether the program terminates with probability 1(almost-sure termination) and (ii) whether the expected termination time is finite (finite termination); andquantitative ones that ask (i) to approximate the expected termination time (expectation problem) and (ii) tocompute a boundBsuch that the probability not to terminate afterBsteps decreases exponentially (con-centration problem). To solve these questions, we utilize the notion of ranking supermartingales, which isa powerful approach for proving termination of probabilistic programs. In detail, we focus on algorithmicsynthesis of linear ranking-supermartingales over affine probabilistic programs (Apps) with both angelic anddemonic non-determinism. An important subclass of Apps is LRApp which is defined as the class of all Appsover which a linear ranking-supermartingale exists.Our main contributions are as follows. Firstly, we show that the membership problem of LRApp (i) canbe decided in polynomial time for Apps with at most demonic non-determinism, and (ii) isNP-hard and inPSPACEfor Apps with angelic non-determinism. Moreover, theNP-hardness result holds already for Appswithout probability and demonic non-determinism. Secondly, we show that the concentration problem overLRApp can be solved in the same complexity as for the membership problem of LRApp. Finally, we show thatthe expectation problem over LRApp can be solved in2EXPTIMEand isPSPACE-hard even for Apps withoutprobability and non-determinism (i.e., deterministic programs). Our experimental results demonstrate theeffectiveness of our approach to answer the qualitative and quantitative questions over Apps with at mostdemonic non-determinism.}, author = {Chatterjee, Krishnendu and Fu, Hongfei and Novotný, Petr and Hasheminezhad, Rouzbeh}, issn = {0164-0925}, journal = {ACM Transactions on Programming Languages and Systems}, number = {2}, publisher = {Association for Computing Machinery (ACM)}, title = {{Algorithmic analysis of qualitative and quantitative termination problems for affine probabilistic programs}}, doi = {10.1145/3174800}, volume = {40}, year = {2018}, } @article{5999, abstract = {We introduce for each quiver Q and each algebraic oriented cohomology theory A, the cohomological Hall algebra (CoHA) of Q, as the A-homology of the moduli of representations of the preprojective algebra of Q. This generalizes the K-theoretic Hall algebra of commuting varieties defined by Schiffmann-Vasserot. When A is the Morava K-theory, we show evidence that this algebra is a candidate for Lusztig's reformulated conjecture on modular representations of algebraic groups. We construct an action of the preprojective CoHA on the A-homology of Nakajima quiver varieties. We compare this with the action of the Borel subalgebra of Yangian when A is the intersection theory. We also give a shuffle algebra description of this CoHA in terms of the underlying formal group law of A. As applications, we obtain a shuffle description of the Yangian. }, author = {Yang, Yaping and Zhao, Gufang}, issn = {0024-6115}, journal = {Proceedings of the London Mathematical Society}, number = {5}, pages = {1029--1074}, publisher = {Oxford University Press}, title = {{The cohomological Hall algebra of a preprojective algebra}}, doi = {10.1112/plms.12111}, volume = {116}, year = {2018}, } @article{5989, abstract = {Schistosomes are the causative agents of schistosomiasis, a neglected tropical disease affecting over 230 million people worldwide.Additionally to their major impact on human health, they are also models of choice in evolutionary biology. These parasitic flatwormsare unique among the common hermaphroditic trematodes as they have separate sexes. This so-called “evolutionary scandal”displays a female heterogametic genetic sex-determination system (ZZ males and ZW females), as well as a pronounced adult sexualdimorphism. These phenotypic differences are determined by a shared set of genes in both sexes, potentially leading to intralocussexual conflicts. To resolve these conflicts in sexually selected traits, molecular mechanisms such as sex-biased gene expression couldoccur, but parent-of-origin gene expression also provides an alternative. In this work we investigated the latter mechanism, that is,genes expressed preferentially from either the maternal or the paternal allele, inSchistosoma mansonispecies. To this end, tran-scriptomes from male and female hybrid adults obtained by strain crosses were sequenced. Strain-specific single nucleotide poly-morphism (SNP) markers allowed us to discriminate the parental origin, while reciprocal crosses helped to differentiate parentalexpression from strain-specific expression. We identified genes containing SNPs expressed in a parent-of-origin manner consistentwith paternal and maternal imprints. Although the majority of the SNPs was identified in mitochondrial and Z-specific loci, theremaining SNPs found in male and female transcriptomes were situated in genes that have the potential to explain sexual differencesin schistosome parasites. Furthermore, we identified and validated four new Z-specific scaffolds.}, author = {Kincaid-Smith, Julien and Picard, Marion A L and Cosseau, Céline and Boissier, Jérôme and Severac, Dany and Grunau, Christoph and Toulza, Eve}, issn = {1759-6653}, journal = {Genome Biology and Evolution}, number = {3}, pages = {840--856}, publisher = {Oxford University Press}, title = {{Parent-of-Origin-Dependent Gene Expression in Male and Female Schistosome Parasites}}, doi = {10.1093/gbe/evy037}, volume = {10}, year = {2018}, } @inproceedings{6031, abstract = {We introduce Clover, a new library for efficient computation using low-precision data, providing mathematical routines required by fundamental methods in optimization and sparse recovery. Our library faithfully implements variants of stochastic quantization that guarantee convergence at low precision, and supports data formats from 4-bit quantized to 32-bit IEEE-754 on current Intel processors. In particular, we show that 4-bit can be implemented efficiently using Intel AVX despite the lack of native support for this data format. Experimental results with dot product, matrix-vector multiplication (MVM), gradient descent (GD), and iterative hard thresholding (IHT) demonstrate that the attainable speedups are in many cases close to linear with respect to the reduction of precision due to reduced data movement. Finally, for GD and IHT, we show examples of absolute speedup achieved by 4-bit versus 32-bit, by iterating until a given target error is achieved.}, author = {Stojanov, Alen and Smith, Tyler Michael and Alistarh, Dan-Adrian and Puschel, Markus}, booktitle = {2018 IEEE International Workshop on Signal Processing Systems}, location = {Cape Town, South Africa}, publisher = {IEEE}, title = {{Fast quantized arithmetic on x86: Trading compute for data movement}}, doi = {10.1109/SiPS.2018.8598402}, volume = {2018-October}, year = {2018}, } @inproceedings{25, abstract = {Partially observable Markov decision processes (POMDPs) are the standard models for planning under uncertainty with both finite and infinite horizon. Besides the well-known discounted-sum objective, indefinite-horizon objective (aka Goal-POMDPs) is another classical objective for POMDPs. In this case, given a set of target states and a positive cost for each transition, the optimization objective is to minimize the expected total cost until a target state is reached. In the literature, RTDP-Bel or heuristic search value iteration (HSVI) have been used for solving Goal-POMDPs. Neither of these algorithms has theoretical convergence guarantees, and HSVI may even fail to terminate its trials. We give the following contributions: (1) We discuss the challenges introduced in Goal-POMDPs and illustrate how they prevent the original HSVI from converging. (2) We present a novel algorithm inspired by HSVI, termed Goal-HSVI, and show that our algorithm has convergence guarantees. (3) We show that Goal-HSVI outperforms RTDP-Bel on a set of well-known examples.}, author = {Horák, Karel and Bošanský, Branislav and Chatterjee, Krishnendu}, booktitle = {Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence}, location = {Stockholm, Sweden}, pages = {4764 -- 4770}, publisher = {IJCAI}, title = {{Goal-HSVI: Heuristic search value iteration for goal-POMDPs}}, doi = {10.24963/ijcai.2018/662}, volume = {2018-July}, year = {2018}, } @inproceedings{24, abstract = {Partially-observable Markov decision processes (POMDPs) with discounted-sum payoff are a standard framework to model a wide range of problems related to decision making under uncertainty. Traditionally, the goal has been to obtain policies that optimize the expectation of the discounted-sum payoff. A key drawback of the expectation measure is that even low probability events with extreme payoff can significantly affect the expectation, and thus the obtained policies are not necessarily risk-averse. An alternate approach is to optimize the probability that the payoff is above a certain threshold, which allows obtaining risk-averse policies, but ignores optimization of the expectation. We consider the expectation optimization with probabilistic guarantee (EOPG) problem, where the goal is to optimize the expectation ensuring that the payoff is above a given threshold with at least a specified probability. We present several results on the EOPG problem, including the first algorithm to solve it.}, author = {Chatterjee, Krishnendu and Elgyütt, Adrian and Novotny, Petr and Rouillé, Owen}, location = {Stockholm, Sweden}, pages = {4692 -- 4699}, publisher = {IJCAI}, title = {{Expectation optimization with probabilistic guarantees in POMDPs with discounted-sum objectives}}, doi = {10.24963/ijcai.2018/652}, volume = {2018}, year = {2018}, } @inproceedings{34, abstract = {Partially observable Markov decision processes (POMDPs) are widely used in probabilistic planning problems in which an agent interacts with an environment using noisy and imprecise sensors. We study a setting in which the sensors are only partially defined and the goal is to synthesize “weakest” additional sensors, such that in the resulting POMDP, there is a small-memory policy for the agent that almost-surely (with probability 1) satisfies a reachability objective. We show that the problem is NP-complete, and present a symbolic algorithm by encoding the problem into SAT instances. We illustrate trade-offs between the amount of memory of the policy and the number of additional sensors on a simple example. We have implemented our approach and consider three classical POMDP examples from the literature, and show that in all the examples the number of sensors can be significantly decreased (as compared to the existing solutions in the literature) without increasing the complexity of the policies.}, author = {Chatterjee, Krishnendu and Chemlík, Martin and Topcu, Ufuk}, location = {Delft, Netherlands}, pages = {47 -- 55}, publisher = {AAAI Press}, title = {{Sensor synthesis for POMDPs with reachability objectives}}, volume = {2018}, year = {2018}, } @article{18, abstract = {An N-superconcentrator is a directed, acyclic graph with N input nodes and N output nodes such that every subset of the inputs and every subset of the outputs of same cardinality can be connected by node-disjoint paths. It is known that linear-size and bounded-degree superconcentrators exist. We prove the existence of such superconcentrators with asymptotic density 25.3 (where the density is the number of edges divided by N). The previously best known densities were 28 [12] and 27.4136 [17].}, author = {Kolmogorov, Vladimir and Rolinek, Michal}, issn = {0381-7032}, journal = {Ars Combinatoria}, number = {10}, pages = {269 -- 304}, publisher = {Charles Babbage Research Centre}, title = {{Superconcentrators of density 25.3}}, volume = {141}, year = {2018}, } @article{6355, abstract = {We prove that any cyclic quadrilateral can be inscribed in any closed convex C1-curve. The smoothness condition is not required if the quadrilateral is a rectangle.}, author = {Akopyan, Arseniy and Avvakumov, Sergey}, issn = {2050-5094}, journal = {Forum of Mathematics, Sigma}, publisher = {Cambridge University Press}, title = {{Any cyclic quadrilateral can be inscribed in any closed convex smooth curve}}, doi = {10.1017/fms.2018.7}, volume = {6}, year = {2018}, }