queueing process with excluded volume effect we introduce an extension of the m m 1 queueing process with a spatial structure and excluded volume effect the rule of particle hopping is the same as for the totally asymmetric simple exclusion process tasep a stationary state solution is constructed in a slightly arranged matrix product form of the open tasep we obtain the critical line that separates the parameter space depending on whether the model has the stationary state we calculate the average length of the model and the number of particles and show the monotonicity of the probability of the length in the stationary state we also consider a generalization of the model with backward hopping of particles allowed and an alternate joined system of the m m 1 queueing process and the open tasep

exact solution of a 1d asymmetric exclusion model using a matrix formulation several recent works have shown that the one dimensional fully asymmetric exclusion model which describes a system of particles hopping in a preferred direction with hard core interactions can be solved exactly in the case of open boundaries here the authors present a new approach based on representing the weights of each configuration in the steady state as a product of noncommuting matrices with this approach the whole solution of the problem is reduced to finding two matrices and two vectors which satisfy very simple algebraic rules they obtain several explicit forms for these non commuting matrices which are in the general case infinite dimensional their approach allows exact expressions to be derived for the current and density profiles finally they discuss briefly two possible generalizations of their results the problem of partially asymmetric exclusion and the case of a mixture of two kinds of particles

exclusive queueing process with discrete time in a recent study arita in phys rev e 80 5 051119 2009 an extension of the m m 1 queueing process with the excluded volume effect as in the totally asymmetric simple exclusion process tasep was introduced in this paper we consider its discrete time version the update scheme we take is the parallel one a stationary state solution is obtained in a slightly arranged matrix product form of the discrete time open tasep with the parallel update we find the phase diagram for the existence of the stationary state the critical line which separates the parameter space into regions with and without the stationary state can be written in terms of the stationary current of the open tasep we calculate the average length of the system and the average number of particles

symplectic calabi yau manifolds minimal surfaces and the hyperbolic geometry of the conifold given an so 3 bundle with connection the associated two sphere bundle carries a natural closed 2 form asking that this be symplectic gives a curvature inequality first considered by rezn ikov 34 we study this inequality in the case when the base has dimension four with three main aims firstly we use this approach to construct symplectic six manifolds with c 1 0 which are never kahler e g we produce such manifolds with b 1 0 b 3 and also with c 2 w

exotic smooth structures on small 4 manifolds let m be either mathbb cp 2 3 overline mathbb cp 2 or 3 mathbb cp 2 5 overline mathbb cp 2 we construct the first example of a simply connected irreducible symplectic 4 manifold that is homeomorphic but not diffeomorphic to m

exotic smooth structures on small 4 manifolds with odd signatures let m be 2n 1 mathbb cp 2 2n overline mathbb cp 2 for any integer n 1 we construct an irreducible symplectic 4 manifold homeomorphic to m and also an infinite family of pairwise non diffeomorphic irreducible non symplectic 4 manifolds homeomorphic to m we also construct such exotic smooth structures when m is mathbb cp 2 4 overline mathbb cp 2 or 3 mathbb cp 2 k overline mathbb cp 2 for k 6 8 10

exact solution of a partially asymmetric exclusion model using a deformed oscillator algebra we study the partially asymmetric exclusion process with open boundaries we generalize the matrix approach previously used to solve the special case of total asymmetry and derive exact expressions for the partition sum and currents valid for all values of the asymmetry parameter q due to the relationship between the matrix algebra and the q deformed quantum harmonic oscillator algebra we find that q hermite polynomials along with their orthogonality properties and generating functions are of great utility we employ two distinct sets of q hermite polynomials one for q 1 it turns out that these correspond to two distinct regimes the previously studied case of forward bias q 1 where the boundaries support a current opposite in direction to the bulk bias for the forward bias case we confirm the previously proposed phase diagram whereas the case of reverse bias produces a new phase in which the current decreases exponentially with system size

knots links and 4 manifolds in this paper we investigate the relationship between isotopy classes of knots and links in s and the di eomorphism types of homeomorphic smooth 4 manifolds as a corollary of this initial investigation we begin to uncover the surprisingly rich structure of di eomorphism types of manifolds homeomorphic to the k3 surface in order to state our theorems we need to view the seiberg witten invariant of a smooth 4 manifold as a multivariable laurent polynomial to do this recall that the seiberg witten invariant of a smooth closed oriented 4 manifold x with b2 x 1 is an integer valued function which is de ned on the set of spinc structures over x cf w km ko1 t1 in case h1 x z has no 2 torsion which will be the situation in this paper there is a natural identi cation of the spinc structures of x with the characteristic elements of h2 x z in this case we view the seiberg witten invariant as

iterated maxima search for the maximally diverse grouping problem the maximally diverse grouping problem mdgp is to partition the vertices of an edge weighted and undirected complete graph into m groups such that the total weight of the groups is maximized subject to some group size constraints mdgp is a np hard combinatorial problem with a number of relevant applications in this paper we present an innovative heuristic algorithm called iterated maxima search ims algorithm for solving mdgp the proposed approach employs a maxima search procedure that integrates organically an efficient local optimization method and a weak perturbation operator to reinforce the intensification of the search and a strong perturbation operator to diversify the search extensive experiments on five sets of 500 mdgp benchmark instances of the literature show that ims competes favorably with the state of the art algorithms we provide additional experiments to shed light on the rationality of the proposed algorithm and investigate the role of the key ingredients

a discrete artificial bee colony algorithm for the total flowtime minimization in permutation flow shops obtaining an optimal solution for a permutation flowshop scheduling problem with the total flowtime criterion in a reasonable computational timeframe using traditional approaches and optimization tools has been a challenge this paper presents a discrete artificial bee colony algorithm hybridized with a variant of iterated greedy algorithms to find the permutation that gives the smallest total flowtime iterated greedy algorithms are comprised of local search procedures based on insertion and swap neighborhood structures in the same context we also consider a discrete differential evolution algorithm from our previous work the performance of the proposed algorithms is tested on the well known benchmark suite of taillard the highly effective performance of the discrete artificial bee colony and hybrid differential evolution algorithms is compared against the best performing algorithms from the existing literature in terms of both solution quality and cpu times ultimately 44 out of the 90 best known solutions provided very recently by the best performing estimation of distribution and genetic local search algorithms are further improved by the proposed algorithms with short term searches the solutions known to be the best to date are reported for the benchmark suite of taillard with long term searches as well

optimizing network attacks by artificial bee colony abstract over the past few years the task of conceiving effective attacks to complex networks has arisen as an optimization problem attacks are modelled as the process of removing a number k of vertices from the graph that represents the network and the goal is to maximise or minimise the value of a predefined metric over the graph in this work we present an optimization problem that concerns the selection of nodes to be removed to minimise the maximum betweenness centrality value of the residual graph this metric evaluates the participation of the nodes in the communications through the shortest paths of the network to address the problem we propose an artificial bee colony algorithm which is a swarm intelligence approach inspired in the foraging behaviour of honeybees in this framework bees produce new candidate solutions for the problem by exploring the vicinity of previous ones called food sources the proposed method exploits useful problem knowledge in this neighbourhood exploration by considering the partial destruction and heuristic reconstruction of selected solutions the performance of the method with respect to other models from the literature that can be adapted to face this problem such as sequential centrality based attacks module based attacks a genetic algorithm a simulated annealing approach and a variable neighbourhood search is empirically shown

dynamical analysis of the exclusive queueing process recently the stationary state of a parallel update totally asymmetric simple exclusion process with varying system length which can be regarded as a queueing process with excluded volume effect exclusive queueing process was obtained c arita and d yanagisawa j stat phys 141 829 2010 in this paper we analyze the dynamical properties of the number of particles n t and the position of the last particle the system length l t using an analytical method generating function technique as well as a phenomenological description based on domain wall dynamics and monte carlo simulations the system exhibits two phases corresponding to linear convergence or divergence of n t and l t these phases can both further be subdivided into high density and maximal current subphases the predictions of the domain wall theory are found to be in very good agreement quantitively with results from monte carlo simulations in the convergent phase on the other hand in the divergent phase only the prediction for n t agrees with simulations

one dimensional partially asymmetric simple exclusion process with open boundaries orthogonal polynomials approach the stationary state of the partially asymmetric simple exclusion process with open boundaries is reconsidered the so called matrix product ansatz is employed this enables us to construct the stationary state in the form of the product of the matrices d and e noticing the fact that the matrix c d e for the model is related to certain q orthogonal polynomials the model is analysed for a wide range of parameters the current and the correlation length are evaluated in the thermodynamic limit it turns out that the phase diagram for the correlation length is richer than that for the totally asymmetric case

a global best artificial bee colony algorithm for global optimization the artificial bee colony abc algorithm is a relatively new optimization technique which has been shown to be competitive to other population based algorithms however there is still an insufficiency in the abc algorithm regarding its solution search equation which is good at exploration but poor at exploitation inspired by differential evolution de we propose a modified abc algorithm denoted as abc best which is based on that each bee searches only around the best solution of the previous iteration in order to improve the exploitation in addition to enhance the global convergence when producing the initial population and scout bees both chaotic systems and opposition based learning method are employed experiments are conducted on a set of 26 benchmark functions the results demonstrate good performance of abc best in solving complex numerical optimization problems when compared with two abc based algorithms

tabu search and grasp for the maximum diversity problem in this paper we develop new heuristic procedures for the maximum diversity problem mdp this np hard problem has a significant number of practical applications such as environmental balance telecommunication services or genetic engineering the proposed algorithm is based on the tabu search methodology and incorporates memory structures for both construction and improvement although proposed in seminal tabu search papers memory based constructions have often been implemented in naive ways that disregard important elements of the fundamental tabu search proposals we will compare our tabu search construction with a memory less design and with previous algorithms recently developed for this problem the constructive method can be coupled with a local search procedure or a short term tabu search for improved outcomes extensive computational experiments with medium and large instances show that the proposed procedure outperforms the best heuristics reported in the literature within short computational times

symplectic conifold transitions we introduce a symplectic surgery in six dimensions which collapses lagrangian three spheres and replaces them by symplectic two spheres under mirror symmetry it corresponds to an operation on complex 3 folds studied by clemens friedman and tian we describe several examples which show that there are either many more calabi yau manifolds e g rigid ones than previously thought or there exist symplectic calabi yaus non kahler symplectic 6 folds with c1 0 the analogous surgery in four dimensions with a generalisation to ade trees of lagrangians implies that the canonical class of a minimal complex surface contains symplectic forms if and only if it has positive square

an artificial bee colony algorithm for the maximally diverse grouping problem in this paper an artificial bee colony algorithm is proposed to solve the maximally diverse grouping problem this complex optimisation problem consists of forming maximally diverse groups with restricted sizes from a given set of elements the artificial bee colony algorithm is a new swarm intelligence technique based on the intelligent foraging behaviour of honeybees the behaviour of this algorithm is determined by two search strategies an initialisation scheme employed to construct initial solutions and a method for generating neighbouring solutions more specifically the proposed approach employs a greedy constructive method to accomplish the initialisation task and also employs different neighbourhood operators inspired by the iterated greedy algorithm in addition it incorporates an improvement procedure to enhance the intensification capability through an analysis of the experimental results the highly effective performance of the proposed algorithm is shown in comparison to the current state of the art algorithms which address the problem

solving the maximally diverse grouping problem by skewed general variable neighborhood search the maximally diverse grouping problem requires finding a partition of a given set of elements into a fixed number of mutually disjoint subsets or groups in order to maximize the overall diversity between elements of the same group in this paper we develop a new variant of variable neighborhood search for solving the problem the extensive computational results show that our new heuristic significantly outperforms the current state of the art moreover the best known solutions have been improved on 531 out of 540 test instances from the literature

the symplectic sum formula for gromov witten invariants in the symplectic category there is a connect sum operation that glues symplectic manifolds by identifying neighborhoods of embedded codimension two submanifolds this paper establishes a formula for the gromov witten invariants of a symplectic sum z x y in terms of the relative gw invariants of x and y several applications to enumerative geometry are given gromov witten invariants are counts of holomorphic maps into symplectic manifolds to define them on a symplectic manifold x w one introduces an almost complex structure j compatible with the symplectic form w and

a swarm intelligence approach to the quadratic minimum spanning tree problem the quadratic minimum spanning tree problem q mst is an extension of the minimum spanning tree problem mst in q mst in addition to edge costs costs are also associated with ordered pairs of distinct edges and one has to find a spanning tree that minimizes the sumtotal of the costs of individual edges present in the spanning tree and the costs of the ordered pairs containing only edges present in the spanning tree though mst can be solved in polynomial time q mst is np hard in this paper we present an artificial bee colony abc algorithm to solve q mst the abc algorithm is a new swarm intelligence approach inspired by intelligent foraging behavior of honey bees computational results show the effectiveness of our approach

a mixed integer programming formulation and solution for traffic analysis zone delineation considering zone amount decision abstract due to the spatial aggregation effect the amount of zones aoz has a direct influence on the optimality of traffic analysis zone delineation tazd problems unlike existing studies this paper addresses a tazd problem in which both the aoz and zone partitions are optimized for the tazd problem we propose a mixed integer programming mip model with the optimization objective of minimizing the sum of geographical errors within each zone to solve the tazd model the following works have been done first the tazd model is strengthened by our proposed ir influence region construction algorithm second based on the strengthened model we analyse the lower bound of the optimal aoz from the theoretical perspective and then the drmi domain reduction method i is proposed to specify a tighter lower bound also to reduce the amount of decision variables we put forward the drmii domain reduction method ii which enumerates all feasible aoz values third to settle a non solution situation we propose the ahcbha aggregation hierarchical clustering based heuristic algorithm in order to rebuild the solution space fourth we then design two methods to solve the tazd model the former method combines the ahcbha with the drmi and the latter method combines the ahcbha with the drmii finally the performance of the proposed tazd and the developed methods is explored using a numerical example and a real world case the obtained results constitute good solutions

limit laws for the asymmetric inclusion process the asymmetric inclusion process asip is a unidirectional lattice gas flow model which was recently introduced as an exactly solvable bosonic counterpart of the fermionic asymmetric exclusion process an iterative algorithm that allows the computation of the probability generating function pgf of the asip s steady state exists but practical considerations limit its applicability to small asip lattices large lattices on the other hand have been studied primarily via monte carlo simulations and were shown to display a wide spectrum of intriguing statistical phenomena in this paper we bypass the need for direct computation of the pgf and explore the asip s asymptotic statistical behavior we consider three different limiting regimes heavy traffic regime large system regime and balanced system regime in each of these regimes we obtain analytically and in closed form stochastic limit laws for five key asip observables traversal time overall load busy period first occupied site and draining time the results obtained yield a detailed limit laws perspective of the asip numerical simulations demonstrate the applicability of these laws as useful approximations

almost complex 4 manifolds with vanishing first chern class an odd seiberg witten invariant imposes bounds on the signature of a closed almost complex 4 manifold with vanishing first chern class this applies in particular to symplectic 4 manifolds of kodaira dimension zero

occupation probabilities and fluctuations in the asymmetric simple inclusion process the asymmetric simple inclusion process asip a lattice gas model of unidirectional transport and aggregation was recently proposed as an inclusion counterpart of the asymmetric simple exclusion process in this paper we present an exact closed form expression for the probability that a given number of particles occupies a given set of consecutive lattice sites our results are expressed in terms of the entries of catalan s trapezoids number arrays which generalize catalan s numbers and catalan s triangle we further prove that the asip is asymptotically governed by the following i an inverse square root law of occupation ii a square root law of fluctuation and iii a rayleigh law for the distribution of interexit times the universality of these results is discussed

symplectic 4 manifolds with kodaira dimension zero we discuss the notion of the kodaira dimension for symplectic manifolds in dimension 4 in particular we propose and partially verify betti number bounds for symplectic 4 manifolds with kodaira dimension zero

exact dynamical state of the exclusive queueing process with deterministic hopping the exclusive queueing process eqp has recently been introduced as a model for the dynamics of queues that takes into account the spatial structure of the queue it can be interpreted as a totally asymmetric exclusion process of varying length here we investigate the case of deterministic bulk hopping p 1 that turns out to be one of the rare cases where exact nontrivial results for the dynamical properties can be obtained using a time dependent matrix product form we calculate several dynamical properties e g the density profile of the system

nonequilibrium steady states of matrix product form a solver s guide we consider the general problem of determining the steady state of stochastic nonequilibrium systems such as those that have been used to model among other things biological transport and traffic flow we begin with a broad overview of this class of driven diffusive systems which includes exclusion processes focusing on interesting physical properties such as shocks and phase transitions we then turn our attention specifically to those models for which the exact distribution of microstates in the steady state can be expressed in a matrix product form in addition to a gentle introduction to this matrix product approach how it works and how it relates to similar constructions that arise in other physical contexts we present a unified pedagogical account of the various means by which the statistical mechanical calculations of macroscopic physical quantities are actually performed we also review a number of more advanced topics including nonequilibrium free energy functionals the classification of exclusion processes involving multiple particle species existence proofs of a matrix product state for a given model and more complicated variants of the matrix product state that allow various types of parallel dynamics to be handled we conclude with a brief discussion of open problems for future research

luttinger surgery along lagrangian tori and non isotopy for singular symplectic plane curves we discuss the properties of a certain type of dehn surgery along a lagrangian torus in a symplectic 4 manifold known as luttinger s surgery and use this construction to provide a purely topological interpretation of a non isotopy result for symplectic plane curves with cusp and node singularities due to moishezon 9

effective ergodicity breaking in an exclusion process with varying system length abstract stochastic processes of interacting particles in systems with varying length are relevant e g for several biological applications we try to explore what kind of new physical effects one can expect in such systems as an example we extend the exclusive queueing process that can be viewed as a one dimensional exclusion process with varying length by introducing langmuir kinetics this process can be interpreted as an effective model for a queue that interacts with other queues by allowing incoming and leaving of customers in the bulk we find surprising indications for breaking of ergodicity in a certain parameter regime where the asymptotic growth behavior depends on the initial length we show that a random walk with site dependent hopping probabilities exhibits qualitatively the same behavior

iterated greedy for the maximum diversity problem abstract the problem of choosing a subset of elements with maximum diversity from a given set is known as the maximum diversity problem many algorithms and methods have been proposed for this hard combinatorial problem including several highly sophisticated procedures by contrast in this paper we present a simple iterated greedy metaheuristic that generates a sequence of solutions by iterating over a greedy construction heuristic using destruction and construction phases extensive computational experiments reveal that the proposed algorithm is highly effective as compared to the best so far metaheuristics for the problem under consideration

iterated greedy local search methods for unrelated parallel machine scheduling abstract this work deals with the parallel machine scheduling problem which consists in the assignment of n jobs on m parallel machines the most general variant of this problem is when the processing time depends on the machine to which each job is assigned to this case is known as the unrelated parallel machine problem similarly to most of the literature this paper deals with the minimization of the maximum completion time of the jobs commonly referred to as makespan c max many algorithms and methods have been proposed for this hard combinatorial problem including several highly sophisticated procedures by contrast in this paper we propose a set of simple iterated greedy local search based metaheuristics that produce solutions of very good quality in a very short amount of time extensive computational campaigns show that these solutions are most of the time better than the current state of the art methodologies by a statistically significant margin

maximal lyapunov exponents for random matrix products in this article we study the lyapunov exponent for random matrix products of positive matrices and express them in terms of associated complex functions this leads to new explicit formulae for the lyapunov exponents and to an efficient method for their computation

one half approximation algorithms for the k partition problem the k partition problem seeks to cluster the vertices of an edge weighted graph g v e into k sets of v k vertices each such that the total weight of the edges having both endpoints in the same cluster is maximized bottom up type heuristics based on matchings are presented for this problem these heuristics are shown to yield solutions that are at least one half the weight of the optimal solution for k equal to v 3 and v 4

symplectic calabi yau 6 manifolds abstract in this article we construct simply connected symplectic calabi yau 6 manifolds by applying gompf s symplectic fiber sum operation along t 4 using our method we also construct symplectic non kahler calabi yau 6 manifolds with fundamental group z this paper also produces the first examples of simply connected and non simply connected symplectic calabi yau 6 manifolds with fundamental groups z p z q and z z q for any p 1 and q 2 via co isotropic luttinger surgery