pinecone/core-2020-05-10-deduplication huggingface dataset:
The Two-Handed Tile Assembly Model Is Not Intrinsically Universal

In this paper, we study the intrinsic universality of the well-studied Two-Handed Tile Assembly Model (2HAM), in which two “supertile” assemblies, each consisting of one or more unit-square tiles, can fuse together (self-assemble) whenever their total attachment strength is at least the global temperature τ. Our main result is that for all τ′ < τ, each temperature-τ′ 2HAM tile system cannot simulate at least one temperature-τ 2HAM tile system. This impossibility result proves that the 2HAM is not intrinsically universal, in stark contrast to the simpler abstract Tile Assembly Model which was shown to be intrinsically universal (The tile assembly model is intrinsically universal, FOCS 2012). On the positive side, we prove that, for every fixed temperature τ ≥ 2, temperature-τ 2HAM tile systems are intrinsically universal: for each τ there is a single universal 2HAM tile set U that, when appropriately initialized, is capable of simulating the behavior of any temperature τ 2HAM tile system. As a corollary of these results we find an infinite set of infinite hierarchies of 2HAM systems with strictly increasing power within each hierarchy. Finally, we show how to construct, for each τ, a temperature-τ 2HAM system that simultaneously simulates all temperature-τ 2HAM systems
Deciding the Winner of an Arbitrary Finite Poset Game is PSPACE-Complete

A poset game is a two-player game played over a partially ordered set (poset)
in which the players alternate choosing an element of the poset, removing it
and all elements greater than it. The first player unable to select an element
of the poset loses. Polynomial time algorithms exist for certain restricted
classes of poset games, such as the game of Nim. However, until recently the
complexity of arbitrary finite poset games was only known to exist somewhere
between NC^1 and PSPACE. We resolve this discrepancy by showing that deciding
the winner of an arbitrary finite poset game is PSPACE-complete. To this end,
we give an explicit reduction from Node Kayles, a PSPACE-complete game in which
players vie to chose an independent set in a graph
Dynamic Compressed Strings with Random Access

We consider the problem of storing a string S in dynamic compressed form, while permitting operations directly on the compressed representation of S: access a substring of S; replace, insert or delete a symbol in S; count how many occurrences of a given symbol appear in any given prefix of S (called rank operation) and locate the position of the ith occurrence of a symbol inside S (called select operation). We discuss the time complexity of several combinations of these operations along with the entropy space bounds of the corresponding compressed indexes. In this way, we extend or improve the bounds of previous work by Ferragina and Venturini [TCS, 2007], Jansson et al. [ICALP, 2012], and Nekrich and Navarro [SODA, 2013].Peer-reviewedPost-print40th International Colloquium, ICALP 2013, Riga, Latvi
On Model-Based RIP-1 Matrices

The Restricted Isometry Property (RIP) is a fundamental property of a matrix enabling sparse recovery [5]. Informally, an m ×n matrix satisfies RIP of order k in the ℓ p norm if ∥ Ax ∥  p  ≈ ∥ x ∥  p for any vector x that is k-sparse, i.e., that has at most k non-zeros. The minimal number of rows m necessary for the property to hold has been extensively investigated, and tight bounds are known. Motivated by signal processing models, a recent work of Baraniuk et al [3] has generalized this notion to the case where the support of x must belong to a given model, i.e., a given family of supports. This more general notion is much less understood, especially for norms other than ℓ2.

In this paper we present tight bounds for the model-based RIP property in the ℓ1 norm. Our bounds hold for the two most frequently investigated models: tree-sparsity and block-sparsity. We also show implications of our results to sparse recovery problems.National Science Foundation (U.S.) (NSF CCF-1065125 award)Danish National Research Foundation (Center for Massive Data Algorithmics (MADALGO))David & Lucile Packard FoundationAkamai Technologies, Inc. (Presidential Fellowship
Fixed-parameter algorithms for minimum cost edge-connectivity augmentation

We consider connectivity-augmentation problems in a setting where each potential new edge has a nonnegative cost associated with it, and the task is to achieve a certain connectivity target with at most p new edges of minimum total cost. The main result is that the minimum cost augmentation of edge-connectivity from k-1 to k with at most p new edges is fixed-parameter tractable parameterized by p and admits a polynomial kernel. We also prove the fixed-parameter tractability of increasing edge-connectivity from 0 to 2, and increasing node-connectivity from 1 to 2. © 2013 Springer-Verlag
Block-sorted quantified conjunctive queries

We study the complexity of model checking in quantified conjunctive logic, that is, the fragment of first-order logic where both quantifiers may be used, but conjunction is the only permitted connective. In particular, we study block-sorted queries, which we define to be prenex sentences in multi-sorted relational first-order logic where two variables having the same sort must appear in the same quantifier block. We establish a complexity classification theorem that describes precisely the sets of block-sorted queries of bounded arity on which model checking is fixed-parameter tractable. This theorem strictly generalizes, for the first time, the corresponding classification for existential conjunctive logic (which is known and due to Grohe) to a logic in which both quantifiers are present. © 2013 Springer-Verlag
Component Reconfiguration in the Presence of Conflicts

International audienceComponents are traditionally modeled as black-boxes equipped with interfaces that indicate provided/required ports and, often, also conflicts with other components that cannot coexist with them. In modern tools for automatic system management, components become grey-boxes that show relevant internal states and the possible actions that can be acted on the components to change such state during the deployment and reconfiguration phases. However, state-of-the-art tools in this field do not support a systematic management of conflicts. In this paper we investigate the impact of conflicts by precisely characterizing the increment of complexity on the reconfiguration problem
Asynchronous Games over Tree Architectures

International audienceWe consider the distributed control problem in the setting of Zielonka asynchronous automata. Such automata are compositions of finite processes communicating via shared actions and evolving asynchronously. Most importantly, processes participating in a shared action can exchange complete information about their causal past. This gives more power to controllers, and avoids simple pathological undecidable cases as in the setting of Pnueli and Rosner. We show the decidability of the control problem for Zielonka automata over acyclic communication architectures. We provide also a matching lower bound, which is l-fold exponential, l being the height of the architecture tree
Temporal network optimization subject to connectivity constraints.

In this work we consider temporal networks, i.e. networks defined by a labeling λ assigning to each edge of an underlying graph G a set of discrete time-labels. The labels of an edge, which are natural numbers, indicate the discrete time moments at which the edge is available. We focus on path problems of temporal networks. In particular, we consider time-respecting paths, i.e. paths whose edges are assigned by λ a strictly increasing sequence of labels. We begin by giving two efficient algorithms for computing shortest time-respecting paths on a temporal network. We then prove that there is a natural analogue of Menger’s theorem holding for arbitrary temporal networks. Finally, we propose two cost minimization parameters for temporal network design. One is the temporality of G, in which the goal is to minimize the maximum number of labels of an edge, and the other is the temporal cost of G, in which the goal is to minimize the total number of labels used. Optimization of these parameters is performed subject to some connectivity constraint. We prove several lower and upper bounds for the temporality and the temporal cost of some very basic graph families such as rings, directed acyclic graphs, and trees
Strong bounds for evolution in networks.

This work extends what is known so far for a basic model of evolutionary antagonism in undirected networks (graphs). More specifically, this work studies the generalized Moran process, as introduced by Lieberman, Hauert, and Nowak [Nature, 433:312-316, 2005], where the individuals of a population reside on the vertices of an undirected connected graph. The initial population has a single mutant of a fitness value r (typically r > 1), residing at some vertex v of the graph, while every other vertex is initially occupied by an individual of fitness 1. At every step of this process, an individual (i.e. vertex) is randomly chosen for reproduction with probability proportional to its fitness, and then it places a copy of itself on a random neighbor, thus replacing the individual that was residing there. The main quantity of interest is the fixation probability, i.e. the probability that eventually the whole graph is occupied by descendants of the mutant. In this work we concentrate on the fixation probability when the mutant is initially on a specific vertex v, thus refining the older notion of Lieberman et al. which studied the fixation probability when the initial mutant is placed at a random vertex. We then aim at finding graphs that have many “strong starts” (or many “weak starts”) for the mutant. Thus we introduce a parameterized notion of selective amplifiers (resp. selective suppressors) of evolution. We prove the existence of strong selective amplifiers (i.e. for h(n) = Θ(n) vertices v the fixation probability of v is at least  1−c(r)n for a function c(r) that depends only on r), and the existence of quite strong selective suppressors. Regarding the traditional notion of fixation probability from a random start, we provide strong upper and lower bounds: first we demonstrate the non-existence of “strong universal” amplifiers, and second we prove the Thermal Theorem which states that for any undirected graph, when the mutant starts at vertex v, the fixation probability at least  (r−1)/(r+degvdegmin). This theorem (which extends the “Isothermal Theorem” of Lieberman et al. for regular graphs) implies an almost tight lower bound for the usual notion of fixation probability. Our proof techniques are original and are based on new domination arguments which may be of general interest in Markov Processes that are of the general birth-death type
V&V of Lexical, Syntactic and Semantic Properties for Interactive Systems Through Model Checking of Formal Description of Dialog

During early phases of the development of an interactive system, future system properties are identified (through interaction with end users in the brainstorming and prototyping phase of the application, or by other stakeholders) imposing requirements on the final system. They can be specific to the application under development or generic to all applications such as usability principles. Instances of specific properties include visibility of the aircraft altitude, speed… in the cockpit and the continuous possibility of disengaging the autopilot in whatever state the aircraft is. Instances of generic properties include availability of undo (for undoable functions) and availability of a progression bar for functions lasting more than four seconds. While behavioral models of interactive systems using formal description techniques provide complete and unambiguous descriptions of states and state changes, it does not provide explicit representation of the absence or presence of properties. Assessing that the system that has been built is the right system remains a challenge usually met through extensive use and acceptance tests. By the explicit representation of properties and the availability of tools to support checking these properties, it becomes possible to provide developers with means for systematic exploration of the behavioral models and assessment of the presence or absence of these properties. This paper proposes the synergistic use two tools for checking both generic and specific properties of interactive applications: Petshop and Java PathFinder. Petshop is dedicated to the description of interactive system behavior. Java PathFinder is dedicated to the runtime verification of Java applications and as an extension dedicated to User Interfaces. This approach is exemplified on a safety critical application in the area of interactive cockpits for large civil aircrafts
Characterizing Incidents Reporting Systems across Applications Domains

Incident reporting is a very well-known technique in application domains such as air traffic management and health, where specialized users are trained to provide detailed information about problems. Incident reporting systems are indeed complex systems that include many actors including the users reporting incidents, user’s colleagues and neighbors, stakeholders, policymakers, systems integrations. Incident report systems might change (positively or negatively) the users’ environment in many ways. In recent years, this kind of technique has been also been used in crisis management such as the hurricane Katrina. However, despite the fact that incident reporting systems using mobile technology are becoming more common, little is known about its actual use by the general population and which factors affect the user experience when using such system. In this paper we discuss the use of incident reporting system in critical context of use. In this paper we discuss the use of incident reporting system in several application domains. In particular we report findings in terms of dimensions that are aimed to identify social and technical aspects that can affect the design, development and use of incident reporting systems
Tuning an HCI Curriculum for Master Students to Address Interactive Critical Systems Aspects

This paper presents the need for specific curricula in order to address the training of specialists in the area of Interactive Critical Systems. Indeed, while curricula are usually built in order to produce specialists in one discipline (e.g. computer science) dealing with systems or products requires training in multiple disciplines. The area of Interactive Critical Systems requires deep knowledge in computer science, dependability, Human-Computer Interaction and safety engineering. We report in this paper how these various disciplines have been integrated in a master program at Université Toulouse III, France and highlight the carrier paths followed by the graduated students and how these carriers are oriented towards aeronautics and space application domains
Opportunities for asteroid retrieval missions

Asteroids and comets are of strategic importance for science in an effort to uncover the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this chapter, we analyze the possibility of retrieving entire objects from accessible heliocentric orbits and moving them into the Earth’s neighbourhood. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun-Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy transfers for asteroidal material. With the objective to minimise transfer costs, a global search of impulsive transfers connecting the unperturbed asteroid’s orbit with the stable manifold phase of the transfer is performed. A catalogue of asteroid retrieval opportunities of currently known NEOs is presented here. Despite the highly incomplete census of very small asteroids, the catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of Δv. All, but one, of these objects have an expected size in the range that can be met by current propulsion technologies. Moreover, the methodology proposed represents a robust search for future retrieval candidates that can be automatically applied to a growing survey of NEOs
Repairing Wireless Sensor Network connectivity with mobility and hop-count constraints

Wireless Sensor Networks can become partitioned due to node failure or damage, and must be repaired by deploying new sensors, relays or sink nodes to restore some quality of service. We formulate the task as a multi-objective problem over two graphs. The solution specifies additional nodes to reconnect a connectivity graph subject to network path-length constraints, and a path through a mobility graph to visit those locations. The objectives are to minimise both the cost of the additional nodes and the length of the mobility path. We propose two heuristic algorithms which prioritise the different objectives. We evaluate the two algorithms on randomly generated graphs, and compare their solutions to the optimal solutions for the individual objectives. Finally, we assess the total restoration time for different classes of agent, i.e. small robots and larger vehicles, which allows us to trade-off longer computation times for shorter mobility paths
Fair private set intersection with a semi-trusted arbiter

A private set intersection (PSI) protocol allows two parties to compute the intersection of their input sets privately. Most of the previous PSI protocols only output the result to one party and the other party gets nothing from running the protocols. However, a mutual PSI protocol in which both parties can get the output is highly desirable in many applications. A major obstacle in designing a mutual PSI protocol is how to ensure fairness. In this paper we present the first fair mutual PSI protocol which is efficient and secure. Fairness of the protocol is obtained in an optimistic fashion, i.e. by using an offline third party arbiter. In contrast to many optimistic protocols which require a fully trusted arbiter, in our protocol the arbiter is only required to be semi-trusted, in the sense that we consider it to be a potential threat to both parties' privacy but believe it will follow the protocol. The arbiter can resolve disputes without knowing any private information belongs to the two parties. This feature is appealing for a PSI protocol in which privacy may be of ultimate importance
Designing copresent cycling experience

There has been much UbiComp research into motivating people to live more active and healthy lifestyle with sports. The idea behind these approaches is centered on social and peer effects in enhancing exercise adherence. While research of this kind has been prolific, there has very little work been done to identify factors that embody comfortable and informed accompanied exercise experience. This paper takes an increasingly attractive cycling theme as a testbed and proposes an unobtrusive and intuitive interface arrangement based on light. It can create a sense of being together with each other for distant apart cyclists. The initial results yield a good level of comprehension and motivation towards the use of the interface. The hope is that the elicited recommendations can guide the design of UbiComp technologies for social motivational physical exercise
Enhancing Approximations for Regular Reachability Analysis

International audienceThis paper introduces two mechanisms for computing over-approximations of sets of reachable states, with the aim of ensuring termination of state-space exploration. The first mechanism consists in over-approximating the automata representing reachable sets by merging some of their states with respect to simple syntactic criteria, or a combination of such criteria. The second approximation mechanism consists in manipulating an auxiliary automaton when applying a transducer representing the transition relation to an automaton encoding the initial states. In addition, for the second mechanism we propose a new approach to refine the approximations depending on a property of interest. The proposals are evaluated on examples of mutual exclusion protocols
Extremal results in random graphs

According to Paul Erd\H{o}s [Some notes on Tur\'an's mathematical work, J.
Approx. Theory 29 (1980), page 4] it was Paul Tur\'an who "created the area of
extremal problems in graph theory". However, without a doubt, Paul Erd\H{o}s
popularized extremal combinatorics, by his many contributions to the field, his
numerous questions and conjectures, and his influence on discrete
mathematicians in Hungary and all over the world. In fact, most of the early
contributions in this field can be traced back to Paul Erd\H{o}s, Paul Tur\'an,
as well as their collaborators and students. Paul Erd\H{o}s also established
the probabilistic method in discrete mathematics, and in collaboration with
Alfr\'ed R\'enyi, he started the systematic study of random graphs. We shall
survey recent developments at the interface of extremal combinatorics and
random graph theory
Optimising problem formulation for cylindrical algebraic decomposition

Cylindrical algebraic decomposition (CAD) is an important tool for the study of real algebraic geometry with many applications both within mathematics and elsewhere. It is known to have doubly exponential complexity in the number of variables in the worst case, but the actual computation time can vary greatly. It is possible to offer different formulations for a given problem leading to great differences in tractability. In this paper we suggest a new measure for CAD complexity which takes into account the real geometry of the problem. This leads to new heuristics for choosing the variable ordering for a CAD problem, choosing a designated equational constraint and choosing clause formulation for truth-table invariant CADs (TTICADs). We then consider the possibility of using Groebner bases to precondition TTICAD and when such formulations constitute the creation of a new problem
Certification of Bounds of Non-linear Functions: the Templates Method

The aim of this work is to certify lower bounds for real-valued multivariate
functions, defined by semialgebraic or transcendental expressions. The
certificate must be, eventually, formally provable in a proof system such as
Coq. The application range for such a tool is widespread; for instance Hales'
proof of Kepler's conjecture yields thousands of inequalities. We introduce an
approximation algorithm, which combines ideas of the max-plus basis method (in
optimal control) and of the linear templates method developed by Manna et al.
(in static analysis). This algorithm consists in bounding some of the
constituents of the function by suprema of quadratic forms with a well chosen
curvature. This leads to semialgebraic optimization problems, solved by
sum-of-squares relaxations. Templates limit the blow up of these relaxations at
the price of coarsening the approximation. We illustrate the efficiency of our
framework with various examples from the literature and discuss the interfacing
with Coq.Comment: 16 pages, 3 figures, 2 table