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1,603 full-text articles. Page 53 of 53.

Improving Resiliency Using Graph Based Evolutionary Algorithms, Jayakanth Jayachandran 2010 Missouri University of Science and Technology

Improving Resiliency Using Graph Based Evolutionary Algorithms, Jayakanth Jayachandran

Masters Theses

"Resiliency is an important characteristic of any system. It signifies the ability of a system to survive and recover from unprecedented disruptions. Various characteristics exist that indicate the level of resiliency in a system. One of these attributes is the adaptability of the system. This adaptability can be enhanced by redundancy present within the system. In the context of system design, redundancy can be achieved by having a diverse set of good designs for that particular system. Evolutionary algorithms are widely used in creating designs for engineering systems, as they perform well on discontinuous and/or high dimensional problems. One ...


Value Of Condition Monitoring For Optimal Replacement In The Proportional Hazards Model With Continuous Degradation, Xiang Wu, Sarah M. Ryan 2010 Iowa State University

Value Of Condition Monitoring For Optimal Replacement In The Proportional Hazards Model With Continuous Degradation, Xiang Wu, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Publications

This article investigates the value of perfect monitoring information for optimal replacement of deteriorating systems in the Proportional Hazards Model (PHM). A continuous-time Markov chain describes the condition of the system. Although the form of an optimal replacement policy for system under periodic monitoring in the PHM was developed previously, an approximation of the Markov process as constant within inspection intervals led to a counter intuitive result that less frequent monitoring could yield a replacement policy with lower average cost. This article explicitly accounts for possible state transitions between inspection epochs to remove the approximation and eliminate the cost anomaly ...


Demand Price Sensitivity And Market Power In A Congested Fuel And Electricity Network, Sarah M. Ryan 2010 Iowa State University

Demand Price Sensitivity And Market Power In A Congested Fuel And Electricity Network, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

IN restructured electricity markets, generating companies submit bids to supply electricity at prices based on their marginal costs, which are driven largely by fuel costs. In each regional wholesale power market, an independent system operator (ISO) manages electricity transmission and sets locational marginal prices (LMPs) to match supplies with demands at each location on the constrained grid. To understand the interaction between constraints on fuel supply and constraints on electricity transmission, we recently developed and tested a game theoretic model that combines both sets of constraints [1][2]. It includes (1) costs of extracting and transporting finite supplies of fuels ...


Elementary Statistical Methods And Measurement Error, Stephen B. Vardeman, Joanne Wendelberger, Tom Burr, Michael S. Hamada, Leslie M. Moore, Marcus Jobe, Max Morris, Huaiqing Wu 2010 Iowa State University

Elementary Statistical Methods And Measurement Error, Stephen B. Vardeman, Joanne Wendelberger, Tom Burr, Michael S. Hamada, Leslie M. Moore, Marcus Jobe, Max Morris, Huaiqing Wu

Industrial and Manufacturing Systems Engineering Publications

How the sources of physical variation interact with a data collection plan determines what can be learned from the resulting dataset, and in particular, how measurement error is reflected in the dataset. The implications of this fact are rarely given much attention in most statistics courses. Even the most elementary statistical methods have their practical effectiveness limited by measurement variation; and understanding how measurement variation interacts with data collection and the methods is helpful in quantifying the nature of measurement error. We illustrate how simple one- and two-sample statistical methods can be effectively used in introducing important concepts of metrology ...


The Effects Of Horizontal Load Speed And Lifting Frequency On Lifting Technique And Biomechanics, Boyi Dai, Sangeun Jin, Xiaopeng Ning, Gary Mirka 2010 Iowa State University

The Effects Of Horizontal Load Speed And Lifting Frequency On Lifting Technique And Biomechanics, Boyi Dai, Sangeun Jin, Xiaopeng Ning, Gary Mirka

Industrial and Manufacturing Systems Engineering Publications

Lifting loads that have a horizontal velocity (e.g. lifting from a conveyor) is often seen in industry and it was hypothesised that the inertial characteristics of these loads may influence lifting technique and low back stress. Seventeen male participants were asked to perform lifting tasks under conditions of four horizontal load speeds (0 m/s, 0.7 m/s, 1.3 m/s and 2.4 m/s) and two lifting frequencies (10 and 20 lifts/min) while trunk motions and trunk muscle activation levels were monitored. Results revealed that increasing horizontal load speed from 0 m/s to ...


An Empirical Validation Of A Base-Excitation Model To Predict Harvestable Energy From A Suspended-Load Backpack System, Xu Xu, Simon M. Hsiang, Gary Mirka 2010 Harvard University

An Empirical Validation Of A Base-Excitation Model To Predict Harvestable Energy From A Suspended-Load Backpack System, Xu Xu, Simon M. Hsiang, Gary Mirka

Industrial and Manufacturing Systems Engineering Publications

Suspended-load backpacks have been proposed as a way to provide power for small electronic devices by capturing the mechanical energy generated by the vertical movement of the suspended load and converting it into electrical energy. The aim of the current study was to build a base excitation model able to predict the relative velocity of the load (an index of the amount of harvestable energy of such a system) using as inputs the mass of the suspended load, the walking speed and the leg length of the user. Nine human participants walked on a treadmill under two load conditions (15 ...


Welfare Effects Of Expansions In Equilibrium Models Of An Electricity Market With Fuel Network, Sarah M. Ryan, Anthony Downward, Andrew Philpott, Golbon Zakeri 2010 Iowa State University

Welfare Effects Of Expansions In Equilibrium Models Of An Electricity Market With Fuel Network, Sarah M. Ryan, Anthony Downward, Andrew Philpott, Golbon Zakeri

Industrial and Manufacturing Systems Engineering Publications

The welfare of electricity producers and consumers depends on congestion in the transmission grid, generation costs that consist mainly of fuel costs, and strategic behavior. We formulate a game theoretic model of an oligopolistic electricity market where generation costs are derived from a fuel supply network. The game consists of a fuel dispatcher that transports fuels at minimum cost to meet generator demands, generators that maximize profit in Cournot competition, and an independent system operator (ISO) that sets nodal prices to balance electricity supply with linear demand functions. We prove the existence of an equilibrium. If fuel supplies are unlimited ...


Metamodel Analysis On Multi-Echelon Supply Chain Simulation Experiments, Laigang Song, Xueping Li, A. Garcia-Diaz 2009 University of Tennessee - Knoxville

Metamodel Analysis On Multi-Echelon Supply Chain Simulation Experiments, Laigang Song, Xueping Li, A. Garcia-Diaz

Xueping Li

No abstract provided.


Key Establishment For Layered Group-Based Wireless Sensor Networks, Xueping Li, Dengfeng Yang, Rapinder Sawhney 2009 University of Tennessee - Knoxville

Key Establishment For Layered Group-Based Wireless Sensor Networks, Xueping Li, Dengfeng Yang, Rapinder Sawhney

Xueping Li

Establishing pairwise keys for sensors is crucial to secure communications in Wireless Sensor Networks (WSNs). Several key pre-distribution schemes have been proposed to establish pairwise keys, but they are not scalable and suffer from a dramatic degradation of security when the number of compromised sensor exceeds a threshold. In this paper, we propose a Layered Group-based Key Establishment (LGKE) scheme, in which a logic top layer ensures the scalability through an Exclusion Basic System (EBS) technique while a logic low layer adopts a group-based key preload scheme to ensure the security. The security analysis and quantitative evaluation show the superiority ...


Icare Software To Train Nurses On Electronic Health Care Records, Xueping Li 2009 University of Tennessee - Knoxville

Icare Software To Train Nurses On Electronic Health Care Records, Xueping Li

Xueping Li

No abstract provided.


Impacts Of Supply Disruptions And Customer Differentiation In A Partial-Backordering Inventory System, Xueping Li, Yuerong Chen 2009 University of Tennessee - Knoxville

Impacts Of Supply Disruptions And Customer Differentiation In A Partial-Backordering Inventory System, Xueping Li, Yuerong Chen

Xueping Li

In this paper, we study a single-product inventory system which involves a supplier, a retailer, and differentiated customers. The supplier provides products to the retailer which in turn sells products to its customers. The supplier is unreliable and is subject to random disruptions. The retailer adopts a periodic-review inventory policy, under which the retailer reviews its inventory position every a fixed period of time and decides whether a replenishment is needed or not. Partial backordering is applied when a stockout occurs. That is, under the situations of stockouts, customers can choose either to backorder products or to abandon the purchase ...


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