# Julia A. BennellUniversity of Leeds · Leeds University Business School

Julia A. Bennell

B.Sc. Ph.D. PGdip

## About

89

Publications

16,928

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2,167

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Introduction

**Skills and Expertise**

## Publications

Publications (89)

Packing Three-Dimensional Irregular Objects
Because of its many applications in practice, the cutting and packing literature is extensive and well established. It is mostly concerned with problems in one and two dimensions or with problems where some regularity of the pieces is assumed (e.g., packing boxes). However, the rise of applications in the...

Research on the three-dimensional (3D) packing problem has largely focused on packing boxes for the transportation of goods. As a result, there has been little focus on packing irregular shapes in the operational research literature. New technologies have raised the practical importance of 3D irregular packing problems and the need for efficient so...

This paper provides a review aimed at comparing cutting and packing (C&P) research in the textile industry and the area of zero-waste fashion design (ZWFD). Both research domains seek to minimise waste material while approaching the problem from very different perspectives. The C&P research investigates the use of mathematical and computational tec...

The paper studies a layout problem of variable number of ellipses with variable sizes placed into an arbitrary disconnected polygonal domain with maximum packing factor. The ellipses can be continuously translated and rotated. Restrictions on the dimensions of the ellipses are taken into account. Tools for the mathematical modelling of placement co...

We consider the problem of loading vehicles onto a ferry. The order in which vehicles arrive at the terminal can have a significant impact on the efficiency of the packing on the ferry as it may not be possible to place a vehicle in an optimal location if it is not at the front of one of the dockside queues at the right point in the loading process...

Organizations have successfully used dynamic pricing to optimize revenues for many years, where research and practice have mainly focused on applications with independent discrete commodities, for example an airline ticket. In this research we consider applications where the commodity cannot be considered independent and the value of the commodity...

This paper presents a two dimensional convex irregular bin packing problem
with guillotine cuts. The problem combines the challenges of tackling the complexity of packing irregular pieces, guaranteeing guillotine cuts that are not always orthogonal to the edges of the bin, and allocating pieces to bins that are not necessarily of the same size. Thi...

We study the problem of packing a given collection of arbitrary, in general concave, polyhedra into a cuboid of minimal volume. Continuous rotations and translations of polyhedra are allowed. In addition, minimal allowable distances between polyhedra are taken into account. We derive an exact mathematical model using adjusted radical free quasi phi...

The restricted continuous facility location problem arises when there is a need to locate a
number of facilities to serve a discrete set of demand points, and where the location of a facility
can be anywhere on the plane except for in restricted regions. The problem nds applications
in urban planning, disaster management, and healthcare logistics....

We propose an heuristic approach to the vehicle ferry revenue management problem, where the aim is to maximize the revenue obtained from the sale of vehicle tickets by varying the prices charged to different vehicle types, each occupying a different amount of deck space. Customers arrive and purchase tickets according to their vehicle type and thei...

In this paper we proposed a local search heuristic and a genetic algorithm to solve the two-dimensional irregular multiple bin-size bin packing problem. The problem consists of placing a set of pieces represented as 2D polygons in rectangular bins with different dimensions such that the total area of bins used is minimized. Most packing algorithms...

The paper investigates the two-dimensional irregular packing problem with
multiple homogeneous bins (2DIBPP). The literature on irregular shaped
packing problems is dominated by the single stock sheet strip packing prob-
lem. However, in reality manufacturers are cutting orders over a multi-stock
sheets. Despite its greater relevance, there are onl...

https://paginas.fe.up.pt/~esicup/extern/esicup-14thMeeting/uploads/Conference/14th_ESICUP_Meeting_booklet_2017.pdf

We propose a Simheuristic approach to the vehicle ferry revenue management problem, where the aim is to maximize the revenue by varying the prices charged to different vehicle types, each occupying a different amount of deck space. Customers arrive and purchase tickets according to their vehicle type and their willingness-to-pay, which varies over...

We present a number of variants of a constructive algorithm able to solve a wide variety of variants of the Two-Dimensional Irregular Bin Packing Problem (2DIBPP). The aim of the 2DIBPP is to pack a set of irregular pieces, which may have concavities, into stock sheets (bins) with fixed dimensions in such a way that the utilization is maximized. Th...

http://www.theorsociety.com/Pages/Conferences/OR58/OR58.aspx

This paper considers the scheduling of aircraft landings on a single runway. There are time window constraints for each aircraft’s landing time, and minimum separation times between consecutive landings, where the separation times depend on the weight classes of the two landing aircraft. A multi-objective formulation takes account of runway through...

https://paginas.fe.up.pt/~esicup/extern/esicup-13thMeeting/uploads/Conference/13th_ESICUP_Meeting_booklet_2016.pdf

This paper presents a general modeling framework for restricted facility location problems with arbitrarily shaped forbidden regions or barriers, where regions are modeled using phi-objects. Phi-objects are an efficient tool in mathematical modeling of 2D and 3D geometric optimization problems, and are widely used in cutting and packing problems an...

This paper addresses the Vehicle Routing Problem (VRP) with time constraints which been solved by several heuristic algorithms. The problem starting at the depot where the customer orders which associated with due date determined by customer, are released with different point of time. Ideally, to avoid any lateness in delivery process, the orders n...

https://paginas.fe.up.pt/~esicup/extern/esicup-12thMeeting/uploads/Conference/12th_ESICUP_Meeting_booklet_2015.pdf

The problem we consider in this study is Time Dependent Vehicle Routing Problem (TDVRP) which has been categorized as non-classical VRP. It is motivated by the fact that multinational companies are currently not only manufacturing the demanded products but also distributing them to the customer location. This implies an efficient synchronization of...

This paper presents an approach for solving a new real problem in cutting and packing. At its core is an innovative mixed integer programme model that places irregular pieces and defines guillotine cuts. The two-dimensional irregular shape bin packing problem with guillotine constraints arises in the glass cutting industry, for example, the cutting...

The research addressing two-dimensional (2D) irregular shape packing has largely focused on the strip packing variant of the problem. However, it can be argued that this is a simplification. The materials from which pieces are required to be cut will ultimately have a fixed length either due to the physical dimensions of the material or through con...

This research is classifies as non-classical Vehicle Routing Problem (VRP) where the maximum release date of customer’s demand of the route determine the vehicle departure time. Thus, there could be lateness on the delivery process from awaiting all customers’ demand of the route to be released. A mathematical formulation is developed to represent...

Three-dimensional cutting and packing problems have a range of important applications and are of particular relevance to the transportation of cargo in the form of container loading problems. Recent years have seen a marked increase in the number of papers examining a variant of the container loading problem ranging from largely theoretical to impl...

Intermodal freight transportation is concerned with the shipment of commodities from their origin to destination using combinations of transport modes. Traditional logistics models have concentrated on minimizing transportation costs by appropriately determining the service network and the transportation routing. This paper considers an intermodal...

Cutting and packing problems arise in many fields of applications and theory. When dealing with irregular objects, an important subproblem is the identification of the optimal clustering of two objects. Within this paper we consider a container (rectangle, circle, convex polygon) of variable sizes and two irregular objects bounded by circular arcs...

The paper examines a new problem in the irregular packing literature that has many applications in industry: two-dimensional irregular (convex) bin packing with guillotine constraints. Due to the cutting process of certain materials, cuts are restricted to extend from one edge of the stock-sheet to another, called guillotine cutting. This constrain...

This paper considers a new variant of the two-dimensional bin packing problem where each rectangle is assigned a due date and each bin has a fixed processing time. Hence the objective is not only to minimize the number of bins, but also to minimize the maximum lateness of the rectangles. This problem is motivated by the cutting of stock sheets and...

The two-dimensional irregular shape bin packing problem with guillotine constraints arises in the glass cutting industry, for example, the cutting of glass for conservatories. Almost all cutting and packing problems that include guillotine cuts deal with rectangles only, where all cuts are orthogonal to the edges of the stock sheet and a maximum of...

This paper introduces a modified shifting bottleneck approach to solve train scheduling and rescheduling problems. The problem is formulated as a job shop scheduling model and a mixed integer linear programming model is also presented. The shifting bottleneck procedure is a well-established heuristic method for obtaining solutions to the job shop a...

Airport runway optimization is an ongoing challenge for air traffic controllers. Since demand for air-transportation is predicted
to increase, there is a need to realize additional take-off and landing slots through better runway scheduling. In this paper,
we review the techniques and tools of operational research and management science that are us...

This paper considers a classical ship scheduling problem in which the routing and scheduling of a heterogeneous fleet of ships with time windows for pick-ups and deliveries at multiple ports is required. Assuming fixed ship speeds, the problem of maximising profit is addressed. A variable neighborhood search metaheuristic is proposed for this probl...

Airport runway optimization is an ongoing challenge for air traffic controllers. Since demand for air-transportation is predicted to increase, there is a need to realize additional take-off and landing slots through better runway scheduling. In this paper, we review the techniques and tools of operational research and management science that are us...

The complexity of the irregular stock-cutting problem makes an ideal candidate for solution using search methods such as simulated annealing or tabu search. Although both were originally intended as generic problem solvers it is now generally accepted that they benefit from the injection of problem-specific knowledge. This paper looks at some of th...

The article reviews the concept of and further develops phi-functions (Φ-functions) as an efficient tool for mathematical
modeling of two-dimensional geometric optimization problems, such as cutting and packing problems and covering problems. The
properties of the phi-function technique and its relationship with Minkowski sums and the nofit polygon...

This paper investigates the irregular shape packing problem. We represent the problem as an ordered list of pieces to be packed
where the order is decoded by a placement heuristic. A placement heuristic from the literature is presented and modified with
a more powerful nofit polygon generator and new evaluation criteria. We implement a beam search...

This paper investigates the stability of the master production schedule (MPS) in a multi-product batch chemical plant, a typical example of manufacturing plants in the process industry. The effects of demand pattern, replanning periodicity, setup costs and unit production cost on the performance of the MPS in a rolling horizon situation are examine...

Biomarkers are proteins or other components of a clinical sample whose measured intensity alters in response to a biological change such as an infection or disease, and which may therefore be useful for prediction and diagnosis. Proteomics is the science of discovering, identifying and understanding such components using tools such as mass spectrom...

Cutting and packing problems have been a core area of research for many decades. Irregular shape packing is one of the most recent variants to be widely researched and its history extends over 40 years. The evolution of solution approaches to this problem can be attributed to increased computer power and advances in geometric techniques as well as...

There are two main approaches popular with researchers to solve two dimensional layout optimization problems that involve irregular shapes, where the objective is to find an arrangement of the irregular pieces in order to minimize waste material. In this paper we have grouped them into iterative constructive heuristics (ICH) and those heuristic whi...

There are two main approaches popular with researchers to solve two dimensional layout optimization problems that involve irregular shapes, where the objective is to find an arrangement of the irregular pieces in order to minimize waste material. In this paper we have grouped them into iterative constructive heuristics (ICH) and those heuristic whi...

With the increasing use of geographical information systems (GIS) and route planning software, users have demanded faster, more realistic routes. Traditionally, operational researchers have focused on developing fast exact and heuristic procedures for the point-to-point shortest path problem. To complement these advancements, we extend the function...

The irregular shape-packing problem has received increasing attention over the last 15 years. An analysis of the solution methods identifies two main approaches for representing the solution. These are, representing the solution as a sequence of pieces and searching over the sequence while applying a placement heuristic to generate the layout, and...

We introduce a two-level heuristic approach for solving jobs originated from incompatible job families that aims to minimize the total weighted tardiness. At the first level, an apparent tardiness cost with setups (ATCS) for a single machine is developed. The second level, a tabu search (TS) heuristic is developed that uses the initial solution obt...

Cutting and packing problems involving irregular shapes is an important problem variant with a wide variety of industrial applications. Despite its relevance to industry, research publications are relatively low when compared to other cutting and packing problems. One explanation offered is the perceived difficulty and substantial time investment o...

The nofit polygon is a powerful and effective tool for handling the geometric requirements of solution approaches to irregular cutting and packing problems. Although the concept was first described in 1966, it was not until the early 90s that the general trend of research moved away from direct trigonometry to favour the nofit polygon. Since then,...

The nofit polygon is a powerful and effective tool for handling the geometric requirements of solution approaches to irregular cutting and packing problems. Although the concept was first described in 1966, it was not until the early 90s that the general trend of research moved away from direct trigonometry to favour the nofit polygon. Since then,...

Cutting and packing problems have been a core area of research for many decades. Irregular shape packing is one of the most recent variants to be widely researched and its history extends over 40 years. The evolution of solution approaches to this problem can be attributed to increased computer power and advances in geometric techniques as well as...

The article further develops phi-functions as an efficient tool for mathematical modelling of two-dimensional geometric optimization problems, such as cutting and packing problems and covering problems. The properties of the phi-function technique and its relationship with Minkowski sums and the nofit polygon are discussed. We also describe the adv...

This paper considers a new variant of the two-dimensional bin packing problem where each rectangle is assigned a due date and each bin has a fixed processing time. Hence the objective is not only to minimize the number of bins, but also to minimize the lateness of the rectangles. This problem is motivated by the potential increase efficiency that m...

This paper presents a new approach for generating the nofit polygon (NFP) that is simple, intuitive and computationally efficient. The NFP has in recent years become an important tool for handling the geometric calculations for two-dimensional irregular shape nesting problems. Its value lies in reducing the computational complexity of detecting whe...

This paper addresses a real-life 1.5D cutting stock problem, which arises in a make-to-order plastic company. The problem is to choose a subset from the set of stock rectangles to be used for cutting into a number of smaller rectangular pieces so as to minimize total production cost and meet orders. The total production cost includes not only mater...

Purpose – Tracker funds offer an attractive balance between risk and return, by providing the profit of the index, with the reduced risk associated with the broad market cover. An effectively designed tracker fund will achieve best tracking of the index with minimal running and trading costs. This paper aims to investigate the use of improved optim...

Sovereign credit ratings are becoming increasingly important both within a financial regulatory context and as a necessary prerequisite for the development of emerging capital markets. Using a comprehensive dataset of rating agencies and countries over the period 1989–1999, this paper demonstrates that artificial neural networks (ANN) represent a s...

The paper will present a constructive approach for nesting problems that utilises beam search to guide the generation of efficient layouts. In order to design an effective constructive heuristic it is important to consider two key features; the placement rule and the intelligent search strategy. Many placement heuristics have been investigated by r...

In the area of proteomics, one of the applications is to detect a given type of disease on the basis of patient blood samples. A well-recognized challenge in classification for this type of problem is that there are thousands of features, but only a limited number of samples available. Thus, feature selection becomes an essential procedure to preve...

A two-dimensional bin-packing problem is considered, where bins have processing times, and rectangles have due dates. A new placement heuristic which dynamically searches for the best placement is presented. The search is controlled by a GA with alternative fitness functions for minimising the number of bins and the maximum lateness.

The nofit polygon is a powerful and effective tool for handling the geometric requirements of solution approaches to irregular cutting and packing problems. Although the concept was first described in 1966, it was not until the early 90s that the general trend of research moved away from direct trigonometry to favour the nofit polygon. Since then,...

A constructive approach for nesting problems based on the TOPOS algorithm is presented and improved via a more powerful nofit polygon generator that can efficiently represent holes in the partial solution. Hence the solution quality is less dependent on the placement order and new "best fit" criteria can be utilised.

The nofit polygon is a powerful tool for handling the geometry of nesting problems. A procedure using the mathematical concept of Minkowski sums for calculating the nofit polygon is presented. It is more efficient and reliable than other Minkowski Sum approaches. Computational experience shows that it is general and accessible.

This paper compares the performance of Black–Scholes with an artificial neural network (ANN) in pricing European-style call options on the FTSE 100 index. It is the first extensive study of the performance of ANNs in pricing UK options, and the first to allow for dividends in the closed-form model. For out-of-the-money options, the ANN is clearly s...

This paper compares the performance of Black-Scholes with an artificial neural network (ANN) in pricing European style call options on the FTSE 100 index. It is the first extensive study of the performance of ANNs in pricing UK options, and the first to allow for dividends in the closed-form model. For out-of-the-money options, the ANN is clearly s...

Constructive algorithms have been shown to be an effective solution approach. However, decoding the representation as a permutation of pieces and the layout of the solution is not a 1-1 mapping Hypothesis: there exists significant redundancy in the search algorithm as a result of reproducing the same solution from a different representation

In the min-max loop layout problem, machines are to be arranged around a loop of conveyor belt. The ordering of the machines dictates the number of circuits of the conveyor belt required to manufacture each of several products. The goal is to find an ordering of the machines that minimises the maximum number of circuits required for the manufacture...

Sequential meta-heuristic implementations for the irregular stock-cutting problem have highlighted a number of common problems. The literature suggests a consensus that it is more efficient to allow configurations with overlapping pieces in the solution space and to penalise these in the evaluation function. However, depending on the severity of th...

The nofit polygon is a powerful and effective tool for handling the geometry required for a range of solution approaches to two-dimensional irregular cutting-stock problems. However, unless all the pieces are convex, it is widely perceived as being difficult to implement, and its use has therefore been somewhat limited. The primary purpose of this...

This paper describes a simple, transparent approach for developing competitive bids, based on an appreciation of cost uncertainty and estimates of the probability of winning with different levels of bid. The process offers an ‘applied’ approach which facilitates an iterative approach to bid development and appropriate consideration of important qua...

Sequential meta-heuristic implementations for the irregular stock-cutting problem have highlighted a number of common problems. The literature suggests a consensus that it is more efficient to allow configurations with overlapping pieces in the solution space and to penalise these in the evaluation function. However, depending on the severity of th...

This paper introduces a new improvement heuristic for irregular cutting and packing problems. The method is based on a small number of repetitions of any leftmost placement policy and is particularly effective in situations where computation time is strictly limited but exceeds that required for a single pass approach. Both the algorithm and the ge...

This paper introduces a new improvement heuristic for irregular cutting and packing problems. The method is based on a
small number of repetitions of any leftmost placement policy and is particularly effective in situations where computation
time is strictly limited but exceeds that required for a single pass approach. Both the algorithm and the ge...

Due to an anticipated increase in air traffic during the next decade, air traffic control in busy airports is one of the main challenges confronting controllers in the near future. Since the runway is often a bottleneck in an airport system, there is great interest in optimizing usage of the runway. Our study first presents a brief review of the ai...

## Projects

Project (1)