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A Stochastic Model for Managing an Assemble-To-Order System
No full textOne of the important things that can be attributed to the modernization and advances in technology is to customize manufacturing of the product to the needs of the users. In this paper a common customization production approach, assemble-to-order system, is analyzed. We assume that the demands for the components arrive according to independent Poisson processes and those of the end product follow a versatile point process. The production times are assumed to be exponentially distributed. Due to complexity of the model under study, we will resort to simulation to identify the inventory allocation and production decisions. The simulation approach determines the expected total cost and some key system performance measures for various types of demand processes. Using (s, S)-type inventory and threshold policies for inventory rationing we study an optimization problem. Some interesting numerical examples to bring out the qualitative nature of the demand process (for end products) are presented
Modeling and Simulation in Undergraduate Education in Industrial Engineering Program : Opportunities and Challenges
No full textIndustrial Engineering (IE), as we all know, is centered on people and processes. First, the industrial engineers interact with people to get a better understanding of the problems the businesses and industries face. Secondly, using the skills and techniques learned in the classroom settings, they offer implementable solutions in practice. Further, the Industrial Engineers always look for ways to continuously improve the process and the products. In this talk, we will present the opportunities and challenges that undergraduate IE students as well as the educators face in dealing with two key skill sets: Modeling and Simulation, which are essential (among other skill sets) in providing solutions to a variety of problems in real-life applications
A Multi-server Queueing Model with Markovian Arrivals and Phase Type Cooperative Services - Simulation Approach
No full textIn Chakravarthy [5] a new class of queueing models in which one type of customers opt for cooperative services with fellow customers was introduced in the context of a single server. Under the assumption of versatile Markovian point process for the arrivals, exponential services, and with a limit of no more than two groups of cooperative customers be present in the system, the model was analyzed in steady-state and some interesting numerical examples were illustrated in [5]. In this paper we generalize that cooperative services model by relaxing the assumptions of single server, exponential services, and only two groups be present at any given time. Thus, we consider a multi-server queueing model in which the customers arrive according to a versatile Markovian point process. One type of customers require individual services whereas the second type of customers opt for a cooperative service (to be offered along with other similar customers). We assume that at any given time there can be at mos K,
Using d–q Transformation to Vary the Switching Frequency for Interior Permanent Magnet Synchronous Motor Drive Systems
No full textThe switching frequency is one of the most important control parameters of the dc/ac inverter. In most motor drives for transportation, it is set as a constant value at some specific torque or speed. The variable switching frequency pulse width modulation (VSFPWM), which changes the switching frequency cycle to cycle based on a current ripple prediction method, has been proposed in previous literatures and realized in resistance- inductance (RL) loads and induction motors (IMs). It proves effective to increase the overall system efficiency and improve electromagnetic interference (EMI) performance. However, the previous current ripple prediction method encounters difficulty in dealing with more complex motors, e.g., interior permanent magnet (IPM) motors, which is widely used in electric vehicles. As a result, the benefits of VSFPWM cannot be fully utilized for IPM drive systems. This paper proposed a new current ripple prediction method using the d-q transformation instead of the conventional Thevenin equivalent circuit method and successfully implemented VSFPWM to IPM drives. Simulation and experiments on a 400-V IPM test bench validated the effectiveness of the method, which will vary the switching frequency from cycle to cycle in order to 1) restrain the three-phase current ripples; 2) increase the overall system efficiency; and 3) enhance the system electromagnetic capability (EMC)
Stochastic Analysis for Gaussian Random Processes and Fields: With Applications
No full textStochastic Analysis for Gaussian Random Processes and Fields: With Applications presents Hilbert space methods to study deep analytic properties connecting probabilistic notions. In particular, it studies Gaussian random fields using reproducing kernel Hilbert spaces (RKHSs).
The book begins with preliminary results on covariance and associated RKHS before introducing the Gaussian process and Gaussian random fields. The authors use chaos expansion to define the Skorokhod integral, which generalizes the Itô integral. They show how the Skorokhod integral is a dual operator of Skorokhod differentiation and the divergence operator of Malliavin. The authors also present Gaussian processes indexed by real numbers and obtain a Kallianpur–Striebel Bayes\u27 formula for the filtering problem. After discussing the problem of equivalence and singularity of Gaussian random fields (including a generalization of the Girsanov theorem), the book concludes with the Markov property of Gaussian random fields indexed by measures and generalized Gaussian random fields indexed by Schwartz space. The Markov property for generalized random fields is connected to the Markov process generated by a Dirichlet form
2015 Self-Study
No full textThis document is intended to fulfill the self-study requirement associated with ABET’s 2015 accreditation review of the electrical engineering program at Kettering University. It has been prepared in accordance with the Engineering Accreditation Commission’s ABET Self-Study Questionnaire: Template for a Self-Study Report (dated August 7, 2014), with reference to ABET’s Criteria for Accrediting Engineering Programs (dated November 7, 2014)