A Job-Shop Scheduling Problem with Bidirectional Circular Precedence Constraints

This paper introduces a job-shop scheduling problem (JSP) with bidirectional circular precedence constraints, called BCJSP. In the problem, each job can be started from any operation and continued by its remaining operations in a circular precedence-relation chain via either a clockwise or counterclockwise direction. To solve BCJSP, this paper proposes a multilevel metaheuristic consisting of top-, middle-, and bottom-level algorithms. The top- and middle-level algorithms are population-based metaheuristics, while the bottom-level algorithm is a local search algorithm. The top-level algorithm basically controls a start operation and an operation-precedence-relation direction of each job, so that BCJSP becomes a JSP instance that is a subproblem of BCJSP. Moreover, the top-level algorithm can also be used to control input parameters of the middle-level algorithm, as an optional extra function. The middle-level algorithm controls input parameters of the bottom-level algorithm, and the bottom-level algorithm then solves the BCJSP’s subproblem. The middle-level algorithm evolves the bottom-level algorithm’s parameter values by using feedback from the bottom-level algorithm. Likewise, the top-level algorithm evolves the start operations, the operation-precedence-relation directions, and the middle-level algorithm’s parameter values by using feedback from the middle-level algorithm. Performance of two variants of the multilevel metaheuristic (i.e., with and without the mentioned extra function) was evaluated on BCJSP instances modified from well-known JSP instances. The variant with the extra function performs significantly better in number than the other. The existing JSP-solving algorithms can also solve BCJSP; however, their results on BCJSP are clearly worse than those of the two variants of the multilevel metaheuristic.

On the temporal structure of nonculminating accomplishments

In the growing body of literature on nonculmination one question seems to have attracted less attention than it may deserve: why do some but not all accomplishment predicates allow for nonculminating interpretations? The goal of this paper is to review attested restrictions on nonculminating accomplishments and to explore one specific aspect of their meaning. Assuming, with the literature on predicate decomposition, that accomplishments minimally consist of a process and change of state components, I focus on the temporal structure of the former. The main empirical finding of the study is that a nonculminating reading is unavailable if contextually relevant parts of this component are arranged by the temporal precedence relation in a unique way.

Rock–paper–scissors dynamics from random walks on temporal multiplex networks

We study diffusion on a multiplex network where the contact dynamics between the nodes is governed by a random process and where the waiting-time distribution differs for edges from different layers. We study the impact on a random walk of the competition that naturally emerges between the edges of the different layers. In opposition to previous studies, which have imposed a priori inter-layer competition, the competition is here induced by the heterogeneity of the activity on the different layers. We first study the precedence relation between different edges and by extension between different layers, and show that it determines biased paths for the walker. We also discuss the emergence of cyclic, rock–paper–scissors effects on random walks, when the precedence between layers is non-transitive. Finally, we numerically show the slowing-down effect due to the competition on a multiplex network with heterogeneous layers activity as the walker is likely to be trapped for a longer time either on a single layer, or on an oriented cycle.

Restricted Constraints in the Problem of Maximum Attainable Flow in Minimum Cost in a Network

In this paper we have considered a version of restricted constraints in the problem of maximum attainable flow (capacity) in minimum cost (distance) in a network (Ahmed, Das, & Purusotham, 2012b). By restricted constraints one means that the link(s) (cities or stations or nodes) are completed (or visited) in such a way that a particular link is to be preceded (completed or visited) by another link (precedence relation need not be immediate). Here the aim is to obtained an optimal route of a more realistic situation as to scheduling a restricted constraints to a maximum flows at a minimum cost from a source to a destination. The distance (cost) and arc capacity between any two stations are given.

Asymmetric Merge and Parataxis

I argue that syntactic structure encodes three types of asymmetries. The first corresponds to the asymmetry between mother and daughters nodes that is called dominance, that is, syntactic hierarchy. The second is the selectional asymmetry between sister nodes, which is translated into the precedence relation in the phonological component. The third, called behindance, is an alternative to dominance, and corresponds to parataxis. Parenthesis, coordination, and apposition are analyzed on the basis of behindance. In our derivational model of grammar it is defined as a special type of inclusion that blocks c-command. It follows that parenthetic material can neither move toward the matrix, nor be bound by a constituent from the matrix.

SOME GENERAL PROPERTIES OF A FUZZY SINGLE MACHINE SCHEDULING PROBLEM

In this paper a general formulation of a fuzzy single machine scheduling problem is proposed. Such notions as schedule, precedence relation and cost function in the fuzzy case are defined. The concept of f-regular function, being a generalization of a regular function, known from the classical theory of scheduling is introduced. A wide class of problems with f-regular cost functions is analyzed and some general properties of such problems are shown.