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Automation in construction scheduling: a review of the literature
No full textAutomating the development of construction schedules has been an interesting topic for researchers around the world for almost three decades. Researchers have approached solving scheduling problems with different tools and techniques. Whenever a new artificial intelligence or optimization tool has been introduced, researchers in the construction field have tried to use it to find the answer to one of their key problems—the “better” construction schedule. Each researcher defines this “better” slightly different. This article reviews the research on automation in construction scheduling from 1985 to 2014. It also covers the topic using different approaches, including case-based reasoning, knowledge-based approaches, model-based approaches, genetic algorithms, expert systems, neural networks, and other methods. The synthesis of the results highlights the share of the aforementioned methods in tackling the scheduling challenge, with genetic algorithms shown to be the most dominant approach. Although the synthesis reveals the high applicability of genetic algorithms to the different aspects of managing a project, including schedule, cost, and quality, it exposed a more limited project management application for the other methods
Quantitative Analysis of Shape-Sensitive Interaction of a Charged Nanoplate and a Charged Nanowire
No full textSystems with nanoscale dimensions have attracted great attention for many decades since they manifest interesting size-dependent behavior and have many possible technological applications. While significant progress has been made toward the experimental and theoretical understanding of various phenomena at nanoscale, much is yet is to be explored in fully comprehending how the interplay of several parameters such as shape, size and dimensionality affects the resulting properties. In this work, we study the nature of the interaction in a nanosystem consisting of a charged nanoplate and a charged nanowire. The two constituent nanostructures of this nanosystem represent important building blocks for bottom-up assembly processes. We consider a specific orientation of the two nanostructures and calculate exactly their interaction energy as a function of shape, size and relative distance. With help from suitable though nontrivial mathematical transformations, we are able to derive a closed form exact expression for such an interaction energy. It is shown that the interaction energy of this configuration is very sensitive to shape and depends in a nontrivial way on size and separation distance
Panther - March 2015 - Vol. XCV No. 5
Get PDFhttps://digitalcommons.pvamu.edu/pv-panther-newspapers/1408/thumbnail.jp
Combinatorial Identities for Incomplete Tribonacci Polynomials
Get PDFThe incomplete tribonacci polynomials, denoted by Tn(s)(x), generalize the usual tribonacci polynomials Tn (x) and have been shown to satisfy several algebraic identities. In this paper, we provide a combinatorial interpretation for Tn(s)(x) in terms of weighted linear tilings involving three types of tiles. This allows one not only to supply combinatorial proofs of earlier identities for Tn(s)(x) but also to derive new ones. In the final section, we provide a formula for the ordinary generating function of the sequence Tn(s)(x) for a fixed s, as previously requested. Our derivation is combinatorial in nature and makes use of an identity relating Tn(s)(x) to Tn (x)
A Semi-parametric Approach for Analyzing Longitudinal Measurements with Non-ignorable Missingness Using Regression Spline
Get PDFIn longitudinal studies with missingness, shared parameter models (SPM) provide appropriate framework for the joint modeling of the measurements and missingness process. These models use a set of random effects to account for the interdependence between two processes. Sometimes the longitudinal responses may not be fitted well by using a linear model and some non-parametric methods have to be used. Also, parametric assumptions are typically made for the random effects distribution, and violation of those may affect the parameter estimates and standard errors. To overcome these problems, we propose a semi-parametric model for the joint modelling of longitudinal markers and a missing not at random mechanism. In this model, because of the flexibility in nonparametric regression models, the relationship between the response variables and the covariates has been modeled by semi-parametric mixed effect model. Also, we do not assume any parametric assumption for the random effects distribution and we allow it to be unspecified. The parameter estimations are made using a vertex exchange method. In order to evaluate the performance of the proposed model, we compare SPM using regression spline (Spline-SPM) and semi-parametric SPM (SpSPM) models. We also conduct a simulation study with different parametric assumptions for the random effects distribution. A real example from a recent HIV study is analyzed for illustration of the proposed approach
Controllability of an eco-epidemiological system with disease transmission delay: A theoretical study
Get PDFThis paper deals with the qualitative analysis of a disease transmission delay induced prey preda-tor system in which disease spreads among the predator species only. The growth of the preda-tors’ susceptible and infected subpopulations is assumed as modified Leslie–Gower type. Suffi-cient conditions for the persistence, permanence, existence and stability of equilibrium points are obtained. Global asymptotic stability of the system is investigated around the coexisting equilib-rium using a geometric approach. The existence of Hopf bifurcation phenomenon is also exam-ined with respect to some important parameters of the system. The criterion for disease a trans-mission delay the induced Hopf bifurcation phenomenon is obtained and subsequently, we use a normal form method and the center manifold theorem to examine the nature of the Hopf bifurca-tion. It is clearly observed that competition among predators can drive the system to a stable from an unstable state. Also the infection and competition among predator population enhance the availability of prey for harvesting when their values are high. Finally, some numerical simu-lations are carried out to illustrate the analytical results
Optimal Solution of a Fully Fuzzy Linear Fractional Programming Problem by Using Graded Mean Integration Representation Method
Get PDFIn the present paper, the study of fully fuzzy linear fractional programming problem (FFLFPP) using graded mean integration representation method is discussed where all the parameters and variables are characterized by trapezoidal fuzzy numbers. A computational algorithm has been presented to obtain an optimal solution by applying simplex method. To demonstrate the applicability of the proposed approach, one numerical example is solved. Also to check the efficiency and feasibility of the proposed approach, we compare the results of examples by applying crisp numbers, triangular fuzzy numbers and trapezoidal fuzzy numbers
Independent Monopoly Size In Graphs
Get PDFIn a graph G = (V;E), a set D ⊆V (G) is said to be a monopoly set of G if every vertex v ∈V-D has at least d(v)/ 2 neighbors in D. The monopoly size of G, denoted mo(G), is the minimum cardinality of a monopoly set among all monopoly sets in G. The set D ⊆ V (G) is an independent monopoly set in G if it is both a monopoly set and an independent set in G. The number of vertices in a minimum independent monopoly set in a graph G is the independent monopoly size of G and is denoted by imo(G). In this paper, we study the existence of independent monopoly set in graphs, bounds for imo(G), and some exact values for some standard graphs are obtained. Finally we characterize all graphs of order n with imo(G) = 1; n - 1 and n