Finding the shortest path in the shortest time using PCNN's

A pulse coupled neural network (PCNN) can run mazes nondeterministically (taking all possible paths) with constant time per step. Thus, when a signal emerges, it has taken the shortest path in the shortest time.     

Physarum can compute shortest paths: A short proof

The purpose of this note is to give a short proof that a standard model for the Physarum polycephalum slime mold correctly computes the shortest path in an undirected weighted graph [V. Bonifaci, K. Mehlhorn, G. Varma, Physarum can compute shortest paths, in: Proc. of the 23rd ACM–SIAM Symposium on Discrete Algorithms, SIAM, 2012, pp. 233–240].     

Extended vertical lists for temporal pattern mining from multivariate time series

In this paper, the problem of mining complex temporal patterns in the context of multivariate time series is considered. A new method called the Fast Temporal Pattern Mining with Extended Vertical Lists is introduced. The method is based on an extension of the level‐wise property, which requires a more complex pattern to start at positions within a record where all of the subpatterns of the pattern start. The approach is built around a novel data structure called the Extended Vertical List that tracks positions of the first state of the pattern inside records and links them to appropriate positions of a specific subpattern of the pattern called the prefix. Extensive computational results indicate that the new method performs significantly faster than the previous version of the algorithm for Temporal Pattern Mining; however, the increase in speed comes at the expense of increased memory usage.     

Hardness results on the man-exchange stable marriage problem with short preference lists

We present two hardness results on the man-exchange stable marriage problem, one of which settles a recent conjecture of Irving on the complexity of determining whether a given instance of the stable marriage problem with short preference lists has a man-exchange stable matching.     

Short cycle time systems development

Abstract. An analysis of two studies in the US and Denmark reveals that short cycle time systems development is a new form that can be clearly distinguished among other forms. The distinction consists of a package of five systems development practices. These practices include a focus on completion speed, release‐oriented parallel prototyping, adherence to a fixed architecture, negotiable quality, and an ideal workforce. The package is consistent with amethodical development concepts. Systems are not built in a single project that completes with a delivery, but rather are continually ‘growing’ to adapt to an organizational emergence.     

Short isometric shapelet transform for binary time series classification

Knowledge and Information Systems - In the research area of time series classification, the ensemble shapelet transform algorithm is one of the state-of-the-art algorithms for classification....     

A running time analysis of an Ant Colony Optimization algorithm for shortest paths in directed acyclic graphs

In this paper, we prove polynomial running time bounds for an Ant Colony Optimization (ACO) algorithm for the single-destination shortest path problem on directed acyclic graphs. More specifically, we show that the expected number of iterations required for an ACO-based algorithm with n ants is for graphs with n nodes and m edges, where ρ is an evaporation rate. This result can be modified to show that an ACO-based algorithm for One-Max with multiple ants converges in expected iterations, where n is the number of variables. This result stands in sharp contrast with that of Neumann and Witt, where a single-ant algorithm is shown to require an exponential running time if ρ=O(n−1−ε) for any ε>0.     

A hybrid rolling grey framework for short time series modelling

Neural Computing and Applications - Time series modelling is gaining spectacular popularity in the prediction process of decision making, with applications including real-world management and...     

基于最短时间距离的校园无线网络用户关联性度量

在校园网络中,存在着大量的信息系统,记录着用户的日常行为信息。通过对大量用户的日常轨迹信息分析,可以发现用户之间的行为关联性,度量用户之间的社会关系强度。基于上海某校的校园网络数据特点,提出了一种改进的基于用户时间序列模型,用最短时间距离进行社会关系度量的方法。该方法首先依据用户的行为数据生成用户行为时间序列,并在此基础上进行行为关联性的度量,以反映用户在真实世界中的社会关系强度,并利用地点访问热度修正社会关系强度的分析结果。实验中使用该方法对上海某校的校园网数据进行分析,度量用户关联性强度,验证了该方法的有效性。     

New polynomial time algorithms to compute a set of Pareto optimal paths for multi-objective shortest path problems

Multi-objective shortest path problem (MOSPP) is an active area of research because of its application in a large number of systems such as transportation systems, communication systems, power transmission systems, pipeline distribution systems of water, gas, blood and drainage, neural decision systems, production planning and project planning. In these networks it becomes necessary to find the best path from one node to a specified or all other nodes. The computational complexity of the existing algorithms in the literature to compute all Pareto minimum paths from a specified source node to all other nodes in an MOSPP is of exponential order in the worst case. Instead of generating all the values of the Pareto minimum paths in exponential time, we propose an algorithm to find a set of values of the Pareto minimum paths in polynomial time, which is very significant in many contexts. If an MOSPP of a network is having negative cycle, all the existing algorithm only indicate the existence of the negative cycle, that too after exponential number of operations. However, applying the proposed algorithm, we can find a set of Pareto minimum paths of any MOSPP of a network even if it contains negative cycles. The proposed algorithm is illustrated with examples.     

Parallel algorithms for shortest path problems in polygons

Given ann-vertex simple polygon we address the following problems: (i) find the shortest path between two pointss andd insideP, and (ii) compute the shortestpath tree between a single points and each vertex ofP (which implicitly represents all the shortest paths). We show how to solve the first problem inO(logn) time usingO(n) processors, and the more general second problem inO(log² n) time usingO(n) processors, and the more general second problem inO(log² n) time usingO(n) processors for any simple polygonP. We assume the CREW RAM shared memory model of computation in which concurrent reads are allowed, but no two processors should attempt to simultaneously write in the same memory location. The algorithms are based on the divide-and-conquer paradigm and are quite different from the known sequential algorithmsResearch supported by the Faculty of Graduate Studies and Research (McGill University) grant 276-07     

A structure for access control lists

In order to obtain concise specifications of access rights, the possibility of granting access rights to groups of users was introduced. This gives rise to the problem of forming specifications which refer to arbitrary unions and intersections of groups. The problem is solved by means of a special list structure. The resulting access lists are short and their administration is flexible.     

求解最短路径的遗传算法中若干问题的讨论

针对道路交通网络中的最短路径问题,讨论了遗传算法中遗传算子的设计及运行参数的选择,提出一种新的交叉算子,提高了种群多样性.通过计算机仿真实验,比较了多种遗传算子设计方案的优劣及不同运行参数对算法效果的影响,为实际应用提供了参考.采用VC语言实现该遗传算法,并应用于实际的电子地图中,结果表明了算法的有效性和实用性.     

A predecessor algorithm for ordered lists

A standard problem in processing lists is to find the predecessor of an element. The two major approaches are to search from the beginning of the list or store a back pointer with every element. If the list has N elements, these approaches are O(N) in time and space, respectively. Under conditions discussed below, it is possible to find the predecessor in an ordered list with time O(N^{$\text{1}\text{2}$}) and no additional space.     

New dominance criteria for the generalized permanent labelling algorithm for the shortest path problem with time windows on dense graphs

This paper describes state-dominance criteria for the Generalized Permanent Labelling Algorithm (GPLA) for solving the Shortest Path Problem with Time Windows on dense graphs, which occurs as a subproblem of a vehicle routing problem. These criteria markedly improve its performance. One of the criteria we propose is based on a backward-looking test at the destination node. The other is a dominance test for the label being treated, which avoids the generation of successor states from dominated labels. Both are possible due to a new order of storing the labels for a given node within each bucket: the generated temporary labels are stored and later treated in decreasing service time order and increasing cost order. This order of label treatment, allied with the suggested dominance criteria, results in a significant time execution performance improvement with respect to the basic dense-graph GPLA.     

一种求受顶点数限制的最短路径的新算法

提出了一种基于逆邻接表求受顶点数限制的最短路径的新算法,其时间复杂度为O(m-2)^*w)(m是受限制的顶点数,w是有向图中弧的条数),优于同类算法。采用逆邻接表作为图的存储结构,该算法很容易实现。