The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper we discuss the relation and the difference between two algorithms BrowseRank and PageRank. We analyze their stationary distributions by the ergodic theory of Markov processes. We compare in detail the link graph used in PageRank and the user browsing graph used in BrowseRank. Along with the comparison, the importance of the metadata contained in the user browsing graph is explored.
We consider a perfectly competitive situation consisting of an electricity market (2nd stage) preceded by investment in generating plant capacity (1st stage). The second stage environment is uncertain at the time of investment, hence the first stage also involves trading in financial instruments, eg, hedges against high generation costs due to rising fuel costs. The classical Invisible Hand...
Given a graph G = (V,E) with a cost on each edge in E and a prize at each vertex in V, and a target set V′ ⊆ V, the Prize Collecting Steiner Tree (PCST) problem is to find a tree T interconnecting vertices in V′ that has minimum total costs on edges and maximum total prizes at vertices in T. This problem is NP-hard in general, and it is polynomial-time solvable when graphs G are restricted to 2-trees...
This paper considers a generalization of the capacitated spanning tree, in which some of the nodes have capacity K, and the others have capacity k < K. We prove that the problem can be approximated within a constant factor, and present better approximations when k is 1 or 2.
This paper considers the economic lot-sizing problem with multi-supplier in which the retailer may replenish his inventory from several suppliers. Each supplier is characterized by one of two types of order cost structures: incremental quantity discount cost structure and multiple set-ups cost structure. The problem is challenging due to the mix of different cost structures. By analyzing the optimal...
The availability of large graphs that represent huge road networks has led to a vast amount of experimental research that has been custom-tailored for road networks. There are two primary reasons to investigate graph-generators that construct synthetic graphs similar to real-world road-networks: The wish to theoretically explain noticeable experimental results on these networks and to overcome the...
The problem of computing a Nash equilibrium in a normal form 2-player game (or bimatrix games) is PPAD-complete in general, while it can be efficiently solved in a special subclass which we call regular bimatrix games. The current best approximation algorithm, proposed in [19], achieves a guarantee of 0.3393. In this paper we design a polynomial time algorithm for computing exact and approximate Nash...
We study the relation between the non-tradable shares reform and the refinancing preferences. From the viewpoints of change in market and policy environments led by the reform, we find that right issues dominate before the reform, however, public offerings (including private placement) dominate after reform, which could be attributed to more money encirclement induced by the shift of the public offering...
We present a polynomial-time approximation algorithm for legally coloring as many edges of a given simple graph as possible using two colors. It achieves an approximation ratio of roughly 0.842 and runs in O(n3m) time, where n (respectively, m) is the number of vertices (respectively, edges) in the input graph. The previously best ratio achieved by a polynomial-time approximation...
Bounded-Degree Vertex Deletion is a fundamental problem in graph theory that has new applications in computational biology. In this paper, we address a special case of Bounded-Degree Vertex Deletion, the Co-Path/Cycle Packing problem, which asks to delete as few vertices as possible such that the graph of the remaining (residual) vertices is composed of disjoint paths and simple cycles. The problem...
Based on Gamma Vega-Cornish Fish methodology, this paper propose the algorithm for calculating VaR via adjusting the quantile under the given confidence level using the four moments (e.g. mean, variance, skewness and kurtosis) of the warrants portfolio return and estimating the variance of portfolio by EWMA methodology. Meanwhile, the proposed algorithm considers the attenuation of the effect of history...
In the classical k-vertex cover problem, we wish to find a minimum weight set of vertices that covers at least k edges. In the incremental version of the k-vertex cover problem, we wish to find a sequence of vertices, such that if we choose the smallest prefix of vertices in the sequence that covers at least k edges, this solution is close in value to that of the optimal k-vertex cover solution. The...
This paper presents an iterative, highly parallelizable approach to find good tours for very large instances of the Euclidian version of the well-known Traveling Salesman Problem (TSP). The basic idea of the approach consists of iteratively transforming the TSP instance to another one with smaller size by contracting pseudo backbone edges. The iteration is stopped, if the new TSP instance is small...
We discuss two variations of the moving network Voronoi diagram. The first one addresses the following problem: given a network with n vertices and E edges. Suppose there are m sites (cars, postmen, etc) moving along the network edges and we know their moving trajectories with time information. Which site is the nearest one to a point p located on network edge at time t′? We present an algorithm to...
This paper considers the coordinated production and delivery scheduling problem. We have a planning horizon consisting of z delivery times each with a unique delivery capacity. Suppose we have a set of jobs each with a committed delivery time, processing time, production window, and profit. The company can earn the profit if the job is produced in its production window and delivered before its committed...
The inverse 1-median problem is concerned with modifying the weights of the customers at minimum cost such that a prespecified supplier becomes the 1-median of modified location problem. We first present the model of inverse 1-median problem on trees. Then we propose two algorithms to solve the problem under weighted l ∞ norm with bound constraints on modifications. Based on the approach...
In this paper we show that the problem of identifying an edge (i,j) in a graph G such that there exists an optimal vertex cover S of G containing exactly one of the nodes i and j is NP-hard. Such an edge is called a weak edge. We then develop a polynomial time approximation algorithm for the vertex cover problem with performance guarantee , where σ is an upper bound on a measure...
Hunsaker and Savelsbergh have proposed an algorithm for testing feasibility of a route in the solution to the dial-a-ride problem. The constraints that are checked are load capacity constraints, time windows, ride time bounds and wait time bounds. The algorithm has linear running time. By virtue of a simple example, we show in this work that their algorithm is incorrect. We also prove that by increasing...
To study the genetic variations of a species, one basic operation is to search for occurrences of patterns in a large number of very similar genomic sequences. To build an indexing data structure on the concatenation of all sequences may require a lot of memory. In this paper, we propose a new scheme to index highly similar sequences by taking advantage of the similarity among the sequences. To store...
We consider the problem of online scheduling on 2 uniform machines where one machine is periodically unavailable. The problem is online in the sense that when a job presents, we have to assign it to one of the 2 uniform machines before the next one is seen. Preemption is not allowed. The objective is to minimize makespan. Assume that the speed of the periodically unavailable machine is normalized...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.