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Article

A. Bazezew, J.C. Bruch and J.M. Sloss

Presents numerical algorithms which easily solve both optimal distributed and optimal boundary control problems in a space‐time domain. Analyses two simple cases of…

Abstract

Presents numerical algorithms which easily solve both optimal distributed and optimal boundary control problems in a space‐time domain. Analyses two simple cases of continuous systems. These are the vibrating string and the axially vibrating rod. Using finite difference recurrence schemes, gives numerical results which compare the behaviour of the controlled and uncontrolled systems. Compares the results for special cases in which analytical solutions are obtainable are compared with the results using the general numerical schemes.

Details

Engineering Computations, vol. 14 no. 7
Type: Research Article
ISSN: 0264-4401

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Article

SRINIVAS KODIYALAM, S. ADALI and I.S. SADEK

The optimal thickness distribution of a two‐span continuous beam is determined with the objectives of minimizing the maximum stress, maximizing the fundamental frequency…

Abstract

The optimal thickness distribution of a two‐span continuous beam is determined with the objectives of minimizing the maximum stress, maximizing the fundamental frequency and frequency separation between adjacent frequencies. The self‐weight of the beam is included in the computations. The multiobjective design problem is solved by using the concept of Pareto optimality. The beam thickness is approximated by constant splines. The stress distribution and the frequencies are determined by the finite element method. The optimization of the beam is carried out by the feasible direction method and by employing a quadratic approximation of the thickness function. Numerical results are given for two‐objective design problems. Optimal trade‐off curves, thickness distributions and stress distributions of optimally designed beams are presented in graphical form. The effects of self‐weight and different design objectives on the thickness distribution are investigated.

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Engineering Computations, vol. 9 no. 5
Type: Research Article
ISSN: 0264-4401

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Article

A. Bazezew, J.C. Bruch and J.M. Sloss

Distributed control is an effective method for controlling and suppressing excessive vibrations of continuous systems. Optimal distributed control for a plate problem is…

Abstract

Distributed control is an effective method for controlling and suppressing excessive vibrations of continuous systems. Optimal distributed control for a plate problem is solved utilizing a maximum principle after the introduction of a quadratic index of performance in terms of displacement, velocity and a control force as well as an adjoint variable. The problem is reduced to solving a system of partial differential equations for the state variable and the adjoint variable subjected to boundary, initial and terminal conditions. A numerical algorithm is presented to solve the optimal distributed control problem in the space‐time domain which reduces the computational effort required to solve the initial‐terminal‐boundary value problem. Results obtained for a simply supported, rectangular, thin plate are also presented.

Details

Engineering Computations, vol. 16 no. 6
Type: Research Article
ISSN: 0264-4401

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Article

Mohamed M. Ahmed, Guangchuan Yang, Sherif Gaweesh, Rhonda Young and Fred Kitchener

This paper aims to present a summary of the performance measurement and evaluation plan of the Wyoming connected vehicle (CV) Pilot Deployment Program (WYDOT Pilot).

Abstract

Purpose

This paper aims to present a summary of the performance measurement and evaluation plan of the Wyoming connected vehicle (CV) Pilot Deployment Program (WYDOT Pilot).

Design/methodology/approach

This paper identified 21 specific performance measures as well as approaches to measure the benefits of the WYDOT Pilot. An overview of the expected challenges that might introduce confounding factors to the evaluation effort was outlined in the performance management plan to guide the collection of system performance data.

Findings

This paper presented the data collection approaches and analytical methods that have been established for the real-life deployment of the WYDOT CV applications. Five methodologies for assessing 21 specific performance measures contained within eight performance categories for the operational and safety-related aspects. Analyses were conducted on data collected during the baseline period, and pre-deployment conditions were established for 1 performance measures. Additionally, microsimulation modeling was recommended to aid in evaluating the mobility and safety benefits of the WYDOT CV system, particularly when evaluating system performance under various CV penetration rates and/or CV strategies.

Practical implications

The proposed performance evaluation framework can guide other researchers and practitioners identifying the best performance measures and evaluation methodologies when conducting similar research activities.

Originality/value

To the best of the authors’ knowledge, this is the first research that develops performance measures and evaluation plan for low-volume rural freeway CV system under adverse weather conditions. This paper raised some early insights into how CV technology might achieve the goal of improving safety and mobility and has the potential to guide similar research activities conducted by other agencies.

Details

Journal of Intelligent and Connected Vehicles, vol. 2 no. 2
Type: Research Article
ISSN: 2399-9802

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Article

Cun‐Cen Li, Ming Yang, Ya‐Fei Pang and Shi‐Yang Li

The purpose of this paper is to propose an optimization method by combining artificial immune algorithm and finite element analysis to find the optimal exciting electrode…

Abstract

Purpose

The purpose of this paper is to propose an optimization method by combining artificial immune algorithm and finite element analysis to find the optimal exciting electrode of a piezoceramic plate type ultrasonic motor vibrator.

Design/methodology/approach

The artificial immune algorithm is selected as optimizer for its merit of fast convergence to global optimal solution. The finite element analysis is used to calculate the motion trajectory of contact point. The objective function is the work that the vibrator does to rotor. The design variables are the boundaries of exciting electrode on piezoceramic plate vibrator surface.

Findings

The calculated results and the experimental results show that using this method, both the position and the size of optimal exciting electrode of this ultrasonic motor can be quickly and accurately determined.

Originality/value

In order to successfully design an ultrasonic motor, both the position and the size of the exciting electrode must be investigated, so as to change more electric energy into mechanical energy. In this paper, an optimization method by combining artificial immune algorithm and finite element analysis is proposed for the exciting location optimization of a piezoceramic plate type ultrasonic motor to obtain large power output.

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Article

George J. Besseris

The purpose of this paper is to provide a case study on endorsing process improvement in maritime operations by implementing design of experiments on Lean Six Sigma…

Abstract

Purpose

The purpose of this paper is to provide a case study on endorsing process improvement in maritime operations by implementing design of experiments on Lean Six Sigma performance responses. It is demonstrated how process efficiency and environmental muda may be dealt with simultaneously in a lean‐and‐green project driven by hardcore Six Sigma tools.

Design/methodology/approach

A 16‐run Taguchi‐type orthogonal design was employed to gather data for vessel speed (VS), exhaust gas temperature (EGT) and fuel consumption (FC) as modulated by a total of 15 controlling parameters synchronously. Active dependencies were inferred based on the desirability analysis method on direct process data from a performance log. This log was maintained for a long‐term monitoring during sea voyages of a double skin bulk carrier of 55,000 DWT while in sea service.

Findings

A high composite desirability value was achieved eclipsing the 0.90 mark. Values well over the 0.9 level were also obtained for the three examined individual desirability values of VS, EGT and FC. Leading controlling parameters were discovered to be compressor pressure, fuel pump index, slip, governor index and MIP.

Practical implications

A Lean Six Sigma project is carried out to improve performance characteristics in ordinary maritime operations. While the company in the case study outlined in this article no longer relies on periodic inspections to determine machinery conditions, improvement on key process characteristics were nevertheless deemed worthy of ameliorating. Information retrieval from computerized continuous monitoring systems assisted in conducting experimental designs in order to obtain optimal performance. Specifically, the tuning of vessel main engine running mode was examined aiming at increasing the quality levels of output power to the shaft along with a reduction of NOx emissions.

Originality/value

This work adds an interesting paradigm in the critical field of maritime activities for processes in full gear while operating at sea. Maritime operations are an imperative necessity when expediting international trading transactions. It is the first time that such a case study has emanated from a real pilot Lean Six Sigma project which interlaces process efficiency enhancement with concurrent environmental muda reduction.

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Article

Ha Nguyen, Ann E. Jeffers and Venkatesh Kodur

This paper aims to address a need for improving the structural resilience to multi-hazard threats including fire and progressive collapse caused by the loss of a column.

Abstract

Purpose

This paper aims to address a need for improving the structural resilience to multi-hazard threats including fire and progressive collapse caused by the loss of a column.

Design/methodology/approach

The focus is on a steel moment frame that uses welded-unreinforced flange-bolted web connections between the beams and columns. A three-dimensional finite element (FE) model was created in ABAQUS with temperature-dependent properties for steel based on the Eurocode. The model was validated against experimental data at ambient and elevated temperature.

Findings

The failure mechanisms in the FE model were consistent with experimental observations. Two scenarios were considered: fixed load with increasing temperature (i.e. simulating column failure prior to fire) and fixed temperature with increasing load (i.e. simulating column failure during fire).

Originality/value

A macro element (or component-based) model was also introduced and validated against the FE model and the experimental data, offering the possibility of analyzing large-scale structural systems with reasonable accuracy and improved computational efficiency.

Details

Journal of Structural Fire Engineering, vol. 7 no. 4
Type: Research Article
ISSN: 2040-2317

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Book part

Jennifer Adams and Emily Hannum

Physical victimization at school is little studied in impoverished developing country contexts. Moreover, the role of school and classroom contexts as risk factors remains…

Abstract

Physical victimization at school is little studied in impoverished developing country contexts. Moreover, the role of school and classroom contexts as risk factors remains poorly understood.

The aim of the study is to investigate the prevalence of physical victimization in rural Chinese middle schools as well as the individual, teacher/classroom, and school-level risk factors associated with experiencing physical victimization.

We use two waves of longitudinal, representative survey data to perform a multilevel logistic regression analysis (MLRA) of physical victimization among middle school students from 100 villages in one of China’s poorest provinces. We focus on a subset of questionnaire items that were gathered from students when the sampled children were 13–16 years old. We also utilize student data from the first wave of the survey to control for prior internalizing problems and academic achievement. Finally, we link matched data collected from principal and teacher questionnaires to examine the risk factors for physical victimization associated with students’ microclimates and the wider school environment.

A substantial proportion of middle school students (40%) reported having been beaten by classmates. Elevated risk was found among males; students with prior poor performance in language; students with past internalizing problems; students of female teachers and teachers evaluated as low performing; students in disruptive classrooms; and students in classrooms undergoing mandated reforms.

These findings suggest that efforts to reduce school violence should not only focus on the deficits of individual students, but rather should target practices to alter the within school risk factors associated with microclimates.

Details

Research in the Sociology of Education
Type: Book
ISBN: 978-1-78769-077-6

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Article

FUAD MRAD, M. ASEM ABDUL‐MALAK, SALAH SADEK and ZIAD KHUDR

Robotic industrial applications are very well established in the manufacturing industry, while they are relatively in their infancy phase in the construction sector. The…

Abstract

Robotic industrial applications are very well established in the manufacturing industry, while they are relatively in their infancy phase in the construction sector. The need for automation in construction is clear especially in repetitive tasks. The excavation process, which is generally critical in most construction projects, is a prime example of such tasks. This paper addresses automation assistance in excavation. The work utilized the robotics approach towards the automation of a typical excavator model, whose structure closely resembled that of an industrial manipulator. A simulation package using Matlab was developed using several embedded design and analysis tools. Emulation was also carried out on the RHINO educational robot to confirm the simulation results. The constructed simulation package offered an integrated environment for trajectory design and analysis for an excavator while addressing the constraints related to the excavator structure, safety and stability, and mode of application.

Details

Engineering, Construction and Architectural Management, vol. 9 no. 4
Type: Research Article
ISSN: 0969-9988

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Article

Since the first Volume of this Bibliography there has been an explosion of literature in all the main areas of business. The researcher and librarian have to be able to…

Abstract

Since the first Volume of this Bibliography there has been an explosion of literature in all the main areas of business. The researcher and librarian have to be able to uncover specific articles devoted to certain topics. This Bibliography is designed to help. Volume III, in addition to the annotated list of articles as the two previous volumes, contains further features to help the reader. Each entry within has been indexed according to the Fifth Edition of the SCIMP/SCAMP Thesaurus and thus provides a full subject index to facilitate rapid information retrieval. Each article has its own unique number and this is used in both the subject and author index. The first Volume of the Bibliography covered seven journals published by MCB University Press. This Volume now indexes 25 journals, indicating the greater depth, coverage and expansion of the subject areas concerned.

Details

Management Decision, vol. 23 no. 1
Type: Research Article
ISSN: 0025-1747

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