Optimization (Mathematical Programming)

Development of a large transhipment and production model for the dairy industry

by Peter Mellalieu

Mellalieu, P. J., & Hall, K. R. (1981). Development of a large transhipment and production model for the dairy industry. Proceedings of the Operations Research Society of New Zealand (ORSNZ), 51–61.

Related publications:
Mellalieu, P. J. (1982). A Decision Support System for Corporate Planning in the New Zealand Dairy Industry (Doctor of Philosophy in mathematics, statistics and operations research). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/568

Mellalieu, P. J., & Houlistan, M. (1982). Towards decision support systems in New Zealand. Proceedings of the Operations Research Society of New Zealand (ORSNZ), 99–106. Retrieved from http://unitec.academia.edu/PeterMellalieu/Papers/1571355/Towards_decision_support_systems_in_New_Zealand

Kearney, T. D., Hall, K. R., & Mellalieu, P. J. (1984). Recent Advances in Network Optimization Methods and Applications. Proceedings of the Annual Conference of the United Kingdom Operational Research Society. Presented at the Annual Conference of the United Kingdom Operational Research Society. Retrieved from http://unitec.academia.edu/PeterMellalieu/Papers/1569500/Recent_Advances_in_Network_Optimization_Methods_and_Applications

Mellalieu, P. J., & Hall, K. R. (1983). An Interactive Planning Model for the New Zealand Dairy Industry. Journal of the Operational Research Society, 34, 521–532. doi:10.1057/jors.1983.119

Sankaran, J. K., & Luxton, P. (2003). Logistics in relation to strategy in dairying: The case of New Zealand dairy. International Journal of Operations & Production Management, 23(5), 522–545. doi:10.1108/01443570310471848

A long-range planning model for a large New Zealand dairy company is described. Aspects of the model’s systems design... more A long-range planning model for a large New Zealand dairy company is described. Aspects of the model’s systems design are discussed in relation to the development of an interactive user-oriented system. The system, known as NETPLAN is based on a network flow formulation that maximizes net variable revenues.

State space reduction in modeling traffic network dynamics for dynamic routing under ITS

by Mahyar Movahednejad

Authors: M. Movahednejad, L. Mashayekhy, A. Taghavi and R. Chinnam

Published in: Proc. of the 14th International IEEE Conference on Intelligent Transportation Systems (ITSC 11), pp. 277-282, Washington DC, USA, October 2011.

A merge-and-split mechanism for dynamic virtual organization formation in grids

by Lena Mashayekhy

Co-authored with Dr. Daniel Grosu

Published in: Proc. of the 30th IEEE International Performance Computing and Communications Conference (IPCCC 11), pp. , Orlando, USA, November 2011.

State space reduction in modeling traffic network dynamics for dynamic routing under ITS

by Lena Mashayekhy

Authors: M. Movahednejad, L. Mashayekhy, A. Taghavi and R. Chinnam

Published in: Proc. of the 14th International IEEE Conference on Intelligent Transportation Systems (ITSC 11), pp. 277-282, Washington DC, USA, October 2011.

Painting by Numbers: Nanoparticle‐Based Colorants in the Post‐Empirical Age

by Robin Klupp Taylor

Case study-Technical assessment of the efficiency optimization in direct connected PV-Electrolysis system at Taleghan-Iran

by Reza Taklimi

Solar - Hydrogen -renewable Energy - IRAN - Fuel Cell - Photo-voltaic

Stiffness identification and damage localization via differential evolution algorithms

by Sara Casciati

Casciati S. (2008). “Stiffness identification and damage localization via differential evolution algorithms”. Structural Control & Health Monitoring, 15(3), 436-449. ISSN: 1545-2255.

DATA E LUOGO DI PUBBLICAZIONE: April 2008; John Wiley & Sons, Ltd., Chichester PO19 8SQ, W Sussex, England.

ABSTRACT. The goal of structural health monitoring is to identify which discrepancies between the actual behaviour of... more ABSTRACT. The goal of structural health monitoring is to identify which discrepancies between the actual behaviour of a structure and its reference undamaged state are indicative of damage. For this purpose, an objective function, which minimizes the difference between the measured and theoretical modal characteristics of the structure, is formulated. By selecting the stiffness parameters as optimization variables, a differential evolution algorithm is applied to create successive generations that better reflect the measured response, until a certain tolerance is met. At each step of the algorithm, the current modal parameters are recalculated from the new generation of stiffness matrices to estimate the value of the objective function. This procedure represents a favourable path to solve the so-called ‘inverse problem’. Furthermore, the comparison of the identified stiffness matrix with the initial one allows for damage detection and localization. A numerical example, where a generic structure is discretized into finite elements, is provided.

KEYWORDS: damage; element stiffness matrix; differential evolution algorithm; finite element analyses; modal parameters; objective function; optimization problem

Optimal Design of Steel Sandwich Panel Applications In Ships

by Alan Klanac

A Profit Optimization Decision Support Tool for the Offshore Aquaculture Industry

by Vassos Vassiliou

Backdoors to combinatorial optimization: Feasibility and optimality

by Bistra Dilkina

Synchronized Arc Routing for Snow Plowing Operations

by M. Angelica Salazar Aguilar

Published by Computers & Operations Research
Authors: M. A. Salazar-Aguilar, André Langevin, and Gilbert Laporte

This paper introduces a synchronized arc routing problem for snow plowing operations. In this problem, routes must be... more This paper introduces a synchronized arc routing problem for snow plowing operations. In this problem, routes must be designed in such a way that street segments with two or more lanes in the same direction are plowed simultaneously by different synchronized vehicles. A mixed integer formulation and an adaptive large neighborhood search heuristic are proposed. The performance of the proposed algorithm is evaluated over a large instance set, including artificial and real data. Computational results confirm the efficiency of the algorithm.

Optimization Algorithms in the Reconstruction of MR Images: A Comparative Study

by Mateusz Malinowski

Time that an imaging device needs to produce results is one of the most crucial factors in
medical imaging.... more Time that an imaging device needs to produce results is one of the most crucial factors in
medical imaging. Shorter scanning duration causes fewer artifacts such as those created by
the patient motion. In addition, it increases patient comfort and in the case of some imaging
modalities also decreases exposure to radiation.
There are some possibilities, hardware-based or software-based, to improve the imaging
speed. One way is to speed up the scanning process by acquiring fewer measurements. A
recently developed mathematical framework called compressed sensing shows that it is
possible to accurately recover undersampled images provided a suitable measurement matrix
is used and the image itself has a sparse representation.
Nevertheless, not only measurements are important but also good reconstruction models
are required. Such models are usually expressed as optimization problems.
In this thesis, we concentrated on the reconstruction of the undersampled Magnetic
Resonance (MR) images. For this purpose a complex-valued reconstruction model was
provided. Since the reconstruction should be as quick as possible, fast methods to find the
solution for the reconstruction problem are required. To meet this objective, three popular
algorithms FISTA, Augmented Lagrangian and Non-linear Conjugate Gradient were adopted
to work with our model.
By changing the complex-valued reconstruction model slightly and dualizing the problem,
we obtained an instance of the quadratically constrained quadratic program where both the
objective function and the constraints are twice differentiable. Hence new model opened
doors to two other methods, the first order method which resembles FISTA and is called
in this thesis Normed Constrained Quadratic FGP, and the second order method called
Truncated Newton Primal Dual Interior Point.
Next, in order to compare performance of the methods, we set up the experiments and
evaluated all presented methods against the problem of reconstructing undersampled MR
images. In the experiments we used a number of invocations of the Fourier transform to
measure the performance of all algorithms.
As a result of the experiments we found that in the context of the original model the
performance of Augmented Lagrangian is better than the other two methods. Performance
of Non-linear Conjugate Gradient and FISTA are about the same. In the context of the
extended model Normed Constrained Quadratic FGP beats the Truncated Newton Primal
Dual Interior Point method.

Sustainable Transportation Systems: dynamic routing optimization for a last-mile distribution fleet

by Diego Falsini

Co-authored with A. Fumarola and M. M. Schiraldi, published in the Proceedigns of the International Conference “Sustainable Development: the role of industrial engineering”, Monopoli, Bari (Italy), 15-19 September 2009. ISBN: 978-88-904625-0-4

Logistics costs control has always been considered a key issue for business development. In order to decrease... more Logistics costs control has always been considered a key issue for business development. In order to decrease transportation costs, companies are pushed to negotiate lower logistic service prices with Third-Party Logistics Service Providers (3PL) which, in turn, should be able to optimize their processes and reduce their costs in order to preserve the adequate profitability and allow their industrial customers to gain competitive advantage. In this paper a method to reduce industrial costs and negative externalities associated with fleet management on an Hub & Spoke transportation network is presented. We state that the Time Dependent VRP with Pick-up and Deliveries and Time Windows model may be the most suitable for goods distribution problem inside large cities. A dynamic version capable to consider road traffic along with variable congestion effects during the day has been created. Hence, we proposed a quick and flexible heuristic that has been validated with the real data of a subsidiary of a 3PL leader in the express transportation sector. The heuristic has demonstrated to be able to reduce travel time, travelled distance and, at the same time, significantly increase the service level, on top of the relative benefit for the community coming from a substantial reduction of air pollution, noise pollution, congestion and incidentally.

Optimal design of PID controllers using the QFT method

by Argyrios Zolotas

Inverse optimization with endogenous arrival time constraints to calibrate the household activity pattern problem

by Joseph Chow

Chow, J.Y.J., Recker, W.W., 2012. Inverse optimization with endogenous arrival time constraints to calibrate the household activity pattern problem, Transportation Research Part B 46(3), 463-479.

A parameter estimation method is proposed for calibrating the household activity pattern problem so that it can be... more A parameter estimation method is proposed for calibrating the household activity pattern problem so that it can be used as a disaggregate, activity-based analog of the traffic assignment problem for activity-based travel forecasting. Inverse optimization is proposed for estimating parameters of the household activity pattern problem such that the observed behavior is optimal, the patterns can be replicated, and the distribution of the parameters is consistent. In order to fit the model to both the sequencing of activities and the arrival times to those activities, an inverse problem is formulated as a mixed integer linear programming problem such that coefficients of the objectives are jointly estimated along with the goal arrival times to the activities. The formulation is designed to be structurally similar to the equivalent problems defined by Ahuja and Orlin and can be solved exactly with a cutting plane algorithm. The concept of a unique invariant common prior is used to regularize the estimation method, and proven to converge using the Method of Successive Averages. The inverse model is tested on sample households from the 2001 California Household Travel Survey and results indicate a significant improvement over the standard inverse problem in the literature as well as baseline prescriptive models that do not make use of sample data for calibration. Although, not unexpectedly, the estimated optimization model by itself is a relatively poor forecasting model, it may be used in determining responses of a population to spatio-temporal scenarios where revealed preference data is absent.

Modelling the South African fruit export infrastructure: A case study

by Frank Ortmann

Co-authored with JH van Vuuren & FE van Dyk

A description is provided of work performed as part of the fruit logistics infrastructure project commissioned by the... more A description is provided of work performed as part of the fruit logistics infrastructure project commissioned by the South African Deciduous Fruit Producers’ Trust and coordinated by the South African Council for Scientific and Industrial Research, as described in [Van Dyk FE & Maspero E, 2004, An analysis of the South African fruit logistics infrastructure, ORiON, 20(1), pp. 55–72]. After a brief introduction to the problem, two models (a single-commodity graph theoretic model and a multi-commodity mathematical programming model) are derived for determining the maximal weekly flow or throughput of fresh fruit through the South African national export infrastructure. These models are solved for two extreme seasonal export scenarios and the solutions show that no export infrastructure expansion is required in the near future — observed bottlenecks are not fundamental to the infrastructure and its capacities, but are rather due to sub-optimal management and utilisation of the existing infrastructure.

Expanding the Spanish high-speed railway network

by Victor Blanco

Co-authored with J. Puerto and A.B. Ramos. Published in Omega.

This paper presents a model for the expansion of transportation networks incorporating specific requirements about... more This paper presents a model for the expansion of transportation networks incorporating specific requirements about population coverage, budget constraints, intermediate goals and origin–destination flows, among others. The model is applicable to the current expansion project of the Spanish high-speed railway network that has been proposed by the Spanish Government under the program Strategic Planning of Infrastructure and Transport (see source [c]).

Our approach looks for solutions that may be used as additional information in the decision-making process of any network expansion. We report on the application of this methodology to the Spanish railway network and on a computational experience based on simulated data varying the number of cities and time horizons which proves the efficiency of the proposed algorithm.

A VaR Black–Litterman model for the construction of absolute return fund-of-funds

by Miguel Lejeune

Genetic algorithms in optimization: Better than random search

by Alessandro Dias

Non Linear Programming Model for the Timber Market in Cameroon in the Context of REDD

by Ernesto Viscarra