@inproceedings{6195,
  abstract     = {In the context of robotic manipulation and grasping, the shift from a view that is static (force closure of a single posture) and contact-deprived (only contact for force closure is allowed, everything else is obstacle) towards a view that is dynamic and contact-rich (soft manipulation) has led to an increased interest in soft hands. These hands can easily exploit environmental constraints and object surfaces without risk, and safely interact with humans, but present also some challenges. Designing them is difficult, as well as predicting, modelling, and “programming” their interactions with the objects and the environment. This paper tackles the problem of simulating them in a fast and effective way, leveraging on novel and existing simulation technologies. We present a triple-layered simulation framework where dynamic properties such as stiffness are determined from slow but accurate FEM simulation data once, and then condensed into a lumped parameter model that can be used to fast simulate soft fingers and soft hands. We apply our approach to the simulation of soft pneumatic fingers.},
  author       = {Pozzi, Maria and Miguel Villalba, Eder and Deimel, Raphael and Malvezzi, Monica and Bickel, Bernd and Brock, Oliver and Prattichizzo, Domenico},
  isbn         = {9781538630815},
  location     = {Brisbane, Australia},
  publisher    = {IEEE},
  title        = {{Efficient FEM-based simulation of soft robots modeled as kinematic chains}},
  doi          = {10.1109/icra.2018.8461106},
  year         = {2018},
}

@article{62,
  abstract     = {Imaging is a dominant strategy for data collection in neuroscience, yielding stacks of images that often scale to gigabytes of data for a single experiment. Machine learning algorithms from computer vision can serve as a pair of virtual eyes that tirelessly processes these images, automatically detecting and identifying microstructures. Unlike learning methods, our Flexible Learning-free Reconstruction of Imaged Neural volumes (FLoRIN) pipeline exploits structure-specific contextual clues and requires no training. This approach generalizes across different modalities, including serially-sectioned scanning electron microscopy (sSEM) of genetically labeled and contrast enhanced processes, spectral confocal reflectance (SCoRe) microscopy, and high-energy synchrotron X-ray microtomography (μCT) of large tissue volumes. We deploy the FLoRIN pipeline on newly published and novel mouse datasets, demonstrating the high biological fidelity of the pipeline’s reconstructions. FLoRIN reconstructions are of sufficient quality for preliminary biological study, for example examining the distribution and morphology of cells or extracting single axons from functional data. Compared to existing supervised learning methods, FLoRIN is one to two orders of magnitude faster and produces high-quality reconstructions that are tolerant to noise and artifacts, as is shown qualitatively and quantitatively.},
  author       = {Shabazi, Ali and Kinnison, Jeffery and Vescovi, Rafael and Du, Ming and Hill, Robert and Jösch, Maximilian A and Takeno, Marc and Zeng, Hongkui and Da Costa, Nuno and Grutzendler, Jaime and Kasthuri, Narayanan and Scheirer, Walter},
  journal      = {Scientific Reports},
  number       = {1},
  publisher    = {Nature Publishing Group},
  title        = {{Flexible learning-free segmentation and reconstruction of neural volumes}},
  doi          = {10.1038/s41598-018-32628-3},
  volume       = {8},
  year         = {2018},
}

@article{620,
  abstract     = {Clathrin-mediated endocytosis requires the coordinated assembly of various endocytic proteins and lipids at the plasma membrane. Accumulating evidence demonstrates a crucial role for phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) in endocytosis, but specific roles for PtdIns(4)P other than as the biosynthetic precursor of PtdIns(4,5)P2 have not been clarified. In this study we investigated the role of PtdIns(4)P or PtdIns(4,5)P2 in receptor-mediated endocytosis through the construction of temperature-sensitive (ts) mutants for the PI 4-kinases Stt4p and Pik1p and the PtdIns(4) 5-kinase Mss4p. Quantitative analyses of endocytosis revealed that both the stt4(ts)pik1(ts) and mss4(ts) mutants have a severe defect in endocytic internalization. Live-cell imaging of endocytic protein dynamics in stt4(ts)pik1(ts) and mss4(ts) mutants revealed that PtdIns(4)P is required for the recruitment of the alpha-factor receptor Ste2p to clathrin-coated pits whereas PtdIns(4,5)P2 is required for membrane internalization. We also found that the localization to endocytic sites of the ENTH/ANTH domain-bearing clathrin adaptors, Ent1p/Ent2p and Yap1801p/Yap1802p, is significantly impaired in the stt4(ts)pik1(ts) mutant, but not in the mss4(ts) mutant. These results suggest distinct roles in successive steps for PtdIns(4)P and PtdIns(4,5)P2 during receptor-mediated endocytosis.},
  author       = {Yamamoto, Wataru and Wada, Suguru and Nagano, Makoto and Aoshima, Kaito and Siekhaus, Daria E and Toshima, Junko and Toshima, Jiro},
  journal      = {Journal of Cell Science},
  number       = {1},
  publisher    = {Company of Biologists},
  title        = {{Distinct roles for plasma membrane PtdIns 4 P and PtdIns 4 5 P2 during yeast receptor mediated endocytosis}},
  doi          = {10.1242/jcs.207696},
  volume       = {131},
  year         = {2018},
}

@phdthesis{6263,
  abstract     = {Antibiotic  resistance  can  emerge  spontaneously  through  genomic  mutation  and  render treatment   ineffective.   To   counteract   this process, in   addition   to   the   discovery   and description of resistance mechanisms,a deeper understanding of resistanceevolvabilityand its  determinantsis  needed. To address  this challenge,  this  thesisuncoversnew  genetic determinants   of   resistance   evolvability   using   a   customized   robotic   setup, exploressystematic   ways   in   which   resistance   evolution   is   perturbed   due   to dose-responsecharacteristics  of  drugs and  mutation  rate  differences,and  mathematically  investigates the evolutionary fate of one specific type of evolvability modifier -a stress-induced mutagenesis allele.We  find  severalgenes  which  strongly  inhibit  or  potentiate  resistance  evolution.  In  order to identify   them,   we   first developedan   automated   high-throughput   feedback-controlled protocol whichkeeps the population size and selection pressure approximately constant for hundreds  of  cultures  by  dynamically  re-diluting  the  cultures  and  adjusting  the  antibiotic concentration.  We  implementedthis  protocol  on  a  customized  liquid  handling  robot  and propagated  100  different  gene  deletion  strains  of Escherichia  coliin  triplicate  for  over  100 generations  in  tetracycline  and  in  chloramphenicol,  and  comparedtheir  adaptation  rates.We  find  a  diminishing  returns  pattern,  where  initially  sensitive  strains  adapted  more compared to less sensitive ones.  Our data uncover that deletions of certain genes which do not  affect  mutation  rate,including  efflux  pump  components,  a  chaperone  and severalstructural  and regulatory  genes  can strongly  and  reproducibly  alterresistance  evolution. Sequencing   analysis of   evolved   populations   indicates   that   epistasis   with   resistance mutations  is  the  most  likelyexplanation. This  work  could  inspire  treatment  strategies  in which  targeted  inhibitors  of  evolvability  mechanisms  will  be  given  alongside  antibiotics  to slow down resistance evolution and extend theefficacy of antibiotics.We implemented  astochasticpopulation  genetics  model, toverifyways  in  which  general properties,  namely,  dose-response  characteristics  of  drugs  and  mutation  rates,  influence evolutionary  dynamics.  In  particular,  under  the  exposure  to  antibiotics  with  shallow  dose-response  curves,bacteria  have  narrower  distributions  of  fitness  effects  of  new  mutations. We  show  that in  silicothis  also  leads  to  slower  resistance  evolution.  We see and  confirm with experiments that increased mutation rates, apart from speeding up evolution, also leadto high reproducibility of phenotypic adaptation in a context of continually strong selection pressure.Knowledge  of  these  patterns  can  aid  in  predicting  the  dynamics  of  antibiotic resistance evolutionand adapting treatment schemes accordingly.Focusing on   a   previously   described   type   of   evolvability   modifier –a   stress-induced mutagenesis  allele –we  find  conditions  under  which  it  can  persist  in  a  population  under periodic  selectionakin  to  clinical  treatment. We  set  up  a  deterministic infinite  populationcontinuous  time  model  tracking  the  frequencies  of  a  mutator  and  resistance  allele  and evaluate  various  treatment  schemes  in  how  well  they  maintain  a stress-induced mutator allele. In particular,a high diversity  of stresses  is  crucial  for  the  persistence of the  mutator allele. This leads to a general trade-off where exactly those diversifying treatment schemes which  are  likely  to  decrease  levels  of  resistance  could  lead  to  stronger  selection  of  highly evolvable genotypes.In  the  long  run,  this  work  will  lead  to  a  deeper  understanding  of  the  genetic  and  cellular mechanisms involved in antibiotic resistance evolution and could inspire new strategies for slowing down its rate. },
  author       = {Lukacisinova, Marta},
  issn         = {2663-337X},
  pages        = {91},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Genetic determinants of antibiotic resistance evolution}},
  doi          = {10.15479/AT:ISTA:th1072},
  year         = {2018},
}

@phdthesis{6266,
  abstract     = {A major challenge in neuroscience research is to dissect the circuits that orchestrate behavior in health and disease. Proteins from a wide range of non-mammalian species, such as microbial opsins, have been successfully transplanted to specific neuronal targets to override their natural communication patterns. The goal of our work is to manipulate synaptic communication in a manner that closely incorporates the functional intricacies of synapses by preserving temporal encoding (i.e. the firing pattern of the presynaptic neuron) and connectivity (i.e. target specific synapses rather than specific neurons). Our strategy to achieve this goal builds on the use of non-mammalian transplants to create a synthetic synapse. The mode of modulation comes from pre-synaptic uptake of a synthetic neurotransmitter (SN) into synaptic vesicles by means of a genetically targeted transporter selective for the SN. Upon natural vesicular release, exposure of the SN to the synaptic cleft will modify the post-synaptic potential through an orthogonal ligand gated ion channel. To achieve this goal we have functionally characterized a mixed cationic methionine-gated ion channel from Arabidopsis thaliana, designed a method to functionally characterize a synthetic transporter in isolated synaptic vesicles without the need for transgenic animals, identified and extracted multiple prokaryotic uptake systems that are substrate specific for methionine (Met), and established a primary/cell line co-culture system that would allow future combinatorial testing of this orthogonal transmitter-transporter-channel trifecta. Synthetic synapses will provide a unique opportunity to manipulate synaptic communication while maintaining the electrophysiological integrity of the pre-synaptic cell. In this way, information may be preserved that was generated in upstream circuits and that could be essential for concerted function and information processing. },
  author       = {Mckenzie, Catherine},
  issn         = {2663-337X},
  pages        = {95},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Design and characterization of methods and biological components to realize synthetic neurotransmission }},
  doi          = {10.15479/at:ista:th_1055},
  year         = {2018},
}

@article{63,
  abstract     = {African cichlids display a remarkable assortment of jaw morphologies, pigmentation patterns, and mating behaviors. In addition to this previously documented diversity, recent studies have documented a rich diversity of sex chromosomes within these fishes. Here we review the known sex-determination network within vertebrates, and the extraordinary number of sex chromosomes systems segregating in African cichlids. We also propose a model for understanding the unusual number of sex chromosome systems within this clade.},
  author       = {Gammerdinger, William J and Kocher, Thomas},
  journal      = {Genes},
  number       = {10},
  publisher    = {MDPI AG},
  title        = {{Unusual diversity of sex chromosomes in African cichlid fishes}},
  doi          = {10.3390/genes9100480},
  volume       = {9},
  year         = {2018},
}

@article{6339,
  abstract     = {We introduce a diagrammatic Monte Carlo approach to angular momentum properties of quantum many-particle systems possessing a macroscopic number of degrees of freedom. The treatment is based on a diagrammatic expansion that merges the usual Feynman diagrams with the angular momentum diagrams known from atomic and nuclear structure theory, thereby incorporating the non-Abelian algebra inherent to quantum rotations. Our approach is applicable at arbitrary coupling, is free of systematic errors and of finite-size effects, and naturally provides access to the impurity Green function. We exemplify the technique by obtaining an all-coupling solution of the angulon model; however, the method is quite general and can be applied to a broad variety of systems in which particles exchange quantum angular momentum with their many-body environment.},
  author       = {Bighin, Giacomo and Tscherbul, Timur and Lemeshko, Mikhail},
  journal      = {Physical Review Letters},
  number       = {16},
  publisher    = {American Physical Society},
  title        = {{Diagrammatic Monte Carlo approach to angular momentum in quantum many-particle systems}},
  doi          = {10.1103/physrevlett.121.165301},
  volume       = {121},
  year         = {2018},
}

@inproceedings{6340,
  abstract     = {We  present  a  secure  approach  for  maintaining  andreporting  credit  history  records  on  the  Blockchain.  Our  ap-proach  removes  third-parties  such  as  credit  reporting  agen-cies  from  the  lending  process  and  replaces  them  with  smartcontracts.  This  allows  customers  to  interact  directly  with  thelenders  or  banks  while  ensuring  the  integrity,  unmalleabilityand  privacy  of  their  credit  data.  Additionally,  each  customerhas  full  control  over  complete  or  selective  disclosure  of  hercredit records, eliminating the risk of privacy violations or databreaches. Moreover, our approach provides strong guaranteesfor the lenders as well. A lender can check both correctness andcompleteness of the credit data disclosed to her. This is the firstapproach  that  can  perform  all  credit  reporting  tasks  withouta  central  authority  or  changing  the  financial  mechanisms*.},
  author       = {Goharshady, Amir Kafshdar and Behrouz, Ali and Chatterjee, Krishnendu},
  booktitle    = {Proceedings of the IEEE International Conference on Blockchain},
  isbn         = {978-1-5386-7975-3 },
  location     = {Halifax, Canada},
  pages        = {1343--1348},
  publisher    = {IEEE},
  title        = {{Secure Credit Reporting on the Blockchain}},
  doi          = {10.1109/Cybermatics_2018.2018.00231},
  year         = {2018},
}

@article{6354,
  abstract     = {Blood platelets are critical for hemostasis and thrombosis, but also play diverse roles during immune responses. We have recently reported that platelets migrate at sites of infection in vitro and in vivo. Importantly, platelets use their ability to migrate to collect and bundle fibrin (ogen)-bound bacteria accomplishing efficient intravascular bacterial trapping. Here, we describe a method that allows analyzing platelet migration in vitro, focusing on their ability to collect bacteria and trap bacteria under flow.},
  author       = {Fan, Shuxia and Lorenz, Michael and Massberg, Steffen and Gärtner, Florian R},
  issn         = {2331-8325},
  journal      = {Bio-Protocol},
  keywords     = {Platelets, Cell migration, Bacteria, Shear flow, Fibrinogen, E. coli},
  number       = {18},
  publisher    = {Bio-Protocol},
  title        = {{Platelet migration and bacterial trapping assay under flow}},
  doi          = {10.21769/bioprotoc.3018},
  volume       = {8},
  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},
}

@article{6368,
  abstract     = {An optical network of superconducting quantum bits (qubits) is an appealing platform for quantum communication and distributed quantum computing, but developing a quantum-compatible link between the microwave and optical domains remains an outstanding challenge. Operating at T < 100 mK temperatures, as required for quantum electrical circuits, we demonstrate a mechanically mediated microwave–optical converter with 47% conversion efficiency, and use a classical feed-forward protocol to reduce added noise to 38 photons. The feed-forward protocol harnesses our discovery that noise emitted from the two converter output ports is strongly correlated because both outputs record thermal motion of the same mechanical mode. We also discuss a quantum feed-forward protocol that, given high system efficiencies, would allow quantum information to be transferred even when thermal phonons enter the mechanical element faster than the electro-optic conversion rate.},
  author       = {Higginbotham, Andrew P and Burns, P. S. and Urmey, M. D. and Peterson, R. W. and Kampel, N. S. and Brubaker, B. M. and Smith, G. and Lehnert, K. W. and Regal, C. A.},
  issn         = {1745-2473},
  journal      = {Nature Physics},
  number       = {10},
  pages        = {1038--1042},
  publisher    = {Springer Nature},
  title        = {{Harnessing electro-optic correlations in an efficient mechanical converter}},
  doi          = {10.1038/s41567-018-0210-0},
  volume       = {14},
  year         = {2018},
}

@article{6369,
  abstract     = {We construct a metamaterial from radio-frequency harmonic oscillators, and find two topologically distinct phases resulting from dissipation engineered into the system. These phases are distinguished by a quantized value of bulk energy transport. The impulse response of our circuit is measured and used to reconstruct the band structure and winding number of circuit eigenfunctions around a dark mode. Our results demonstrate that dissipative topological transport can occur in a wider class of physical systems than considered before.},
  author       = {Rosenthal, Eric I. and Ehrlich, Nicole K. and Rudner, Mark S. and Higginbotham, Andrew P and Lehnert, K. W.},
  issn         = {2469-9950},
  journal      = {Physical Review B},
  number       = {22},
  publisher    = {American Physical Society (APS)},
  title        = {{Topological phase transition measured in a dissipative metamaterial}},
  doi          = {10.1103/physrevb.97.220301},
  volume       = {97},
  year         = {2018},
}

@article{64,
  abstract     = {Tropical geometry, an established field in pure mathematics, is a place where string theory, mirror symmetry, computational algebra, auction theory, and so forth meet and influence one another. In this paper, we report on our discovery of a tropical model with self-organized criticality (SOC) behavior. Our model is continuous, in contrast to all known models of SOC, and is a certain scaling limit of the sandpile model, the first and archetypical model of SOC. We describe how our model is related to pattern formation and proportional growth phenomena and discuss the dichotomy between continuous and discrete models in several contexts. Our aim in this context is to present an idealized tropical toy model (cf. Turing reaction-diffusion model), requiring further investigation.},
  author       = {Kalinin, Nikita and Guzmán Sáenz, Aldo and Prieto, Y and Shkolnikov, Mikhail and Kalinina, V and Lupercio, Ernesto},
  issn         = {00278424},
  journal      = {PNAS: Proceedings of the National Academy of Sciences of the United States of America},
  number       = {35},
  pages        = {E8135 -- E8142},
  publisher    = {National Academy of Sciences},
  title        = {{Self-organized criticality and pattern emergence through the lens of tropical geometry}},
  doi          = {10.1073/pnas.1805847115},
  volume       = {115},
  year         = {2018},
}

@misc{6459,
  author       = {Petritsch, Barbara},
  keywords     = {Open Access, Publication Analysis},
  location     = {Graz, Austria},
  publisher    = {IST Austria},
  title        = {{Open Access at IST Austria 2009-2017}},
  doi          = {10.5281/zenodo.1410279},
  year         = {2018},
}

@article{6497,
  abstract     = {T cells are actively scanning pMHC-presenting cells in lymphoid organs and nonlymphoid tissues (NLTs) with divergent topologies and confinement. How the T cell actomyosin cytoskeleton facilitates this task in distinct environments is incompletely understood. Here, we show that lack of Myosin IXb (Myo9b), a negative regulator of the small GTPase Rho, led to increased Rho-GTP levels and cell surface stiffness in primary T cells. Nonetheless, intravital imaging revealed robust motility of Myo9b−/− CD8+ T cells in lymphoid tissue and similar expansion and differentiation during immune responses. In contrast, accumulation of Myo9b−/− CD8+ T cells in NLTs was strongly impaired. Specifically, Myo9b was required for T cell crossing of basement membranes, such as those which are present between dermis and epidermis. As consequence, Myo9b−/− CD8+ T cells showed impaired control of skin infections. In sum, we show that Myo9b is critical for the CD8+ T cell adaptation from lymphoid to NLT surveillance and the establishment of protective tissue–resident T cell populations.},
  author       = {Moalli, Federica and Ficht, Xenia and Germann, Philipp and Vladymyrov, Mykhailo and Stolp, Bettina and de Vries, Ingrid and Lyck, Ruth and Balmer, Jasmin and Fiocchi, Amleto and Kreutzfeldt, Mario and Merkler, Doron and Iannacone, Matteo and Ariga, Akitaka and Stoffel, Michael H. and Sharpe, James and Bähler, Martin and Sixt, Michael K and Diz-Muñoz, Alba and Stein, Jens V.},
  issn         = {1540-9538},
  journal      = {The Journal of Experimental Medicine},
  number       = {7},
  pages        = {1869–1890},
  publisher    = {Rockefeller University Press},
  title        = {{The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+T cells}},
  doi          = {10.1084/jem.20170896},
  volume       = {2015},
  year         = {2018},
}

@article{6499,
  abstract     = {Expansion microscopy is a recently introduced imaging technique that achieves super‐resolution through physically expanding the specimen by ~4×, after embedding into a swellable gel. The resolution attained is, correspondingly, approximately fourfold better than the diffraction limit, or ~70 nm. This is a major improvement over conventional microscopy, but still lags behind modern STED or STORM setups, whose resolution can reach 20–30 nm. We addressed this issue here by introducing an improved gel recipe that enables an expansion factor of ~10× in each dimension, which corresponds to an expansion of the sample volume by more than 1,000‐fold. Our protocol, which we termed X10 microscopy, achieves a resolution of 25–30 nm on conventional epifluorescence microscopes. X10 provides multi‐color images similar or even superior to those produced with more challenging methods, such as STED, STORM, and iterative expansion microscopy (iExM). X10 is therefore the cheapest and easiest option for high‐quality super‐resolution imaging currently available. X10 should be usable in any laboratory, irrespective of the machinery owned or of the technical knowledge.},
  author       = {Truckenbrodt, Sven M and Maidorn, Manuel and Crzan, Dagmar and Wildhagen, Hanna and Kabatas, Selda and Rizzoli, Silvio O},
  issn         = {1469-3178},
  journal      = {EMBO reports},
  number       = {9},
  publisher    = {EMBO},
  title        = {{X10 expansion microscopy enables 25‐nm resolution on conventional microscopes}},
  doi          = {10.15252/embr.201845836},
  volume       = {19},
  year         = {2018},
}

@inbook{6525,
  abstract     = {This chapter finds an agreement of equivariant indices of semi-classical homomorphisms between pairwise mirror branes in the GL2 Higgs moduli space on a Riemann surface. On one side of the agreement, components of the Lagrangian brane of U(1,1) Higgs bundles, whose mirror was proposed by Hitchin to be certain even exterior powers of the hyperholomorphic Dirac bundle on the SL2 Higgs moduli space, are present. The agreement arises from a mysterious functional equation. This gives strong computational evidence for Hitchin’s proposal.},
  author       = {Hausel, Tamás and Mellit, Anton and Pei, Du},
  booktitle    = {Geometry and Physics: Volume I},
  isbn         = {9780198802013},
  pages        = {189--218},
  publisher    = {Oxford University Press},
  title        = {{Mirror symmetry with branes by equivariant verlinde formulas}},
  doi          = {10.1093/oso/9780198802013.003.0009},
  year         = {2018},
}

@inproceedings{6558,
  abstract     = {This paper studies the problem of distributed stochastic optimization in an adversarial setting where, out of m machines which allegedly compute stochastic gradients every iteration, an α-fraction are Byzantine, and may behave adversarially. Our main result is a variant of stochastic gradient descent (SGD) which finds ε-approximate minimizers of convex functions in T=O~(1/ε²m+α²/ε²) iterations. In contrast, traditional mini-batch SGD needs T=O(1/ε²m) iterations, but cannot tolerate Byzantine failures. Further, we provide a lower bound showing that, up to logarithmic factors, our algorithm is information-theoretically optimal both in terms of sample complexity and time complexity.},
  author       = {Alistarh, Dan-Adrian and Allen-Zhu, Zeyuan and Li, Jerry},
  booktitle    = {Advances in Neural Information Processing Systems},
  location     = {Montreal, Canada},
  pages        = {4613--4623},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{Byzantine stochastic gradient descent}},
  volume       = {2018},
  year         = {2018},
}

@inproceedings{6589,
  abstract     = {Distributed training of massive machine learning models, in particular deep neural networks, via Stochastic Gradient Descent (SGD) is becoming commonplace. Several families of communication-reduction methods, such as quantization, large-batch methods, and gradient sparsification, have been proposed. To date, gradient sparsification methods--where each node sorts gradients by magnitude, and only communicates a subset of the components, accumulating the rest locally--are known to yield some of the largest practical gains. Such methods can reduce the amount of communication per step by up to \emph{three orders of magnitude}, while preserving model accuracy. Yet, this family of methods currently has no theoretical justification. This is the question we address in this paper. We prove that, under analytic assumptions, sparsifying gradients by magnitude with local error correction provides convergence guarantees, for both convex and non-convex smooth objectives, for data-parallel SGD. The main insight is that sparsification methods implicitly maintain bounds on the maximum impact of stale updates, thanks to selection by magnitude. Our analysis and empirical validation also reveal that these methods do require analytical conditions to converge well, justifying existing heuristics.},
  author       = {Alistarh, Dan-Adrian and Hoefler, Torsten and Johansson, Mikael and Konstantinov, Nikola H and Khirirat, Sarit and Renggli, Cedric},
  booktitle    = {Advances in Neural Information Processing Systems 31},
  location     = {Montreal, Canada},
  pages        = {5973--5983},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{The convergence of sparsified gradient methods}},
  volume       = {Volume 2018},
  year         = {2018},
}

@inproceedings{66,
  abstract     = {Crypto-currencies are digital assets designed to work as a medium of exchange, e.g., Bitcoin, but they are susceptible to attacks (dishonest behavior of participants). A framework for the analysis of attacks in crypto-currencies requires (a) modeling of game-theoretic aspects to analyze incentives for deviation from honest behavior; (b) concurrent interactions between participants; and (c) analysis of long-term monetary gains. Traditional game-theoretic approaches for the analysis of security protocols consider either qualitative temporal properties such as safety and termination, or the very special class of one-shot (stateless) games. However, to analyze general attacks on protocols for crypto-currencies, both stateful analysis and quantitative objectives are necessary. In this work our main contributions are as follows: (a) we show how a class of concurrent mean-payo games, namely ergodic games, can model various attacks that arise naturally in crypto-currencies; (b) we present the first practical implementation of algorithms for ergodic games that scales to model realistic problems for crypto-currencies; and (c) we present experimental results showing that our framework can handle games with thousands of states and millions of transitions.},
  author       = {Chatterjee, Krishnendu and Goharshady, Amir and Ibsen-Jensen, Rasmus and Velner, Yaron},
  isbn         = {978-3-95977-087-3},
  location     = {Beijing, China},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{Ergodic mean-payoff games for the analysis of attacks in crypto-currencies}},
  doi          = {10.4230/LIPIcs.CONCUR.2018.11},
  volume       = {118},
  year         = {2018},
}

