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Past Meetings

Seminar and Quiz

Venue: School of Maths, Cardiff University
Speaker: Professor Steve Disney
Date: Wednesday, 10 December 2014 at 18:00

The Bullwhip Effect in Supply Chains

Prof Stephen Disney, Cardiff University Business School

 Followed by Quiz and Dinner


The next SWORDS meeting of the 2014-2015 programme is scheduled for Wednesday the 10th of December 2014. The meeting will be held at the Mathematics Institute, Cardiff University. There will be drinks available from 5.45pm in the Internet Café which is just inside the main entrance to the Mathematics Institute. The talk will commence at 6.00pm in room M/0.40 (ground floor). This will be followed by a quiz and food starting at approximately 6.30pm.

 There is a charge for the social of £5 for OR Society members and £10 for others (partners are welcome). We need to know in advance who is coming so please let me know asap if you wish to attend. Also let me know if you would like the vegetarian option.

 Please contact Jonathan Thompson, tel: 029-20875524



Supply chains are victims of a dynamical effect called the “Bullwhip Effect”. The bullwhip effect refers to the tendency of the variability of replenishment orders to increase as they pass through the echelons of a supply chain from retailers towards producers and raw material suppliers. A classic example of the effect is baby nappies or diapers. Babies are fairly regular in their use of nappies - they have a new nappy (almost) every time they feed. Sure, the retail sales on a day-to-day basis fluctuate a little, but the demand patterns experiences by the diaper manufacturer are the widely fluctuating and the erratic production rates experienced in the factory can result in a lot of easily avoidable costs.


This bullwhip effect is caused by the fundamental structure of a supply chain. As it takes time to order, manufacture and deliver product, forecasting procedures have to be used to predict future demands and position the supply chain to meet them. These forecasting mechanisms are then used inside replenishment systems and together they amplify the variability of replenishment orders. Other factors also contribute; batch sizing, process capability and uncertainty, promotions and shortage gaming.


This talk first discusses the bullwhip effect and explains why it is important. A (very) brief introduction of the theory behind the phenomena is then highlighted. This is followed by a review of the mitigation and avoidance strategies that are available to allow companies to reduce the bullwhip effect and its impact. Finally, a summary of some cases where bullwhip avoidance has been achieved will be given.


How OR Supports Decision Making at British Airways

Venue: School of Mathematics, Cardiff University
Speaker: Naomi Rowlands and Geraint Thomas (BA)
Date: Wednesday, 12 November 2014 at 17:30 - 19:00

The next SWORDS meeting of the 2014-2015 programme is scheduled for Wednesday the
12th of November 2014. The meeting will be held in room M/0.40 at the Mathematics
Institute, Cardiff University. There will be drinks available from 5.30pm in the Internet Café
which is just inside the main entrance to the Mathematics Institute. The talk will start at 5.45pm.

Everyone's welcome - you could even bring a colleague!

If you have any questions please contact Jonathan Thompson, tel: 029-20875524

British Airways is the UK's largest international airline and one of the world's leading global
premium carriers. It served 40 million passengers last year in 157 destinations across 85
Flying is a complex business, and the airline industry is a varied and challenging environment
to manage. The OR team at British Airways are involved in projects right across the
business, supporting decision-making, initiating change and making key issues less complex.
Come along to hear an overview of the type of work the OR team does at British Airways,
some of the key challenges in recent years, and a number of case studies including the
team's role in fleet purchase decisions and the use of simulation to model passenger flows
through the airport.

Health System Patient Flow Simulation Model

Venue: School of Maths, Cardiff University
Speaker: Michael Carter
Date: Monday, 20 October 2014 at 17:30 - 19:00
Health System Patient Flow Simulation Model
Michael W. Carter
Ali Vahit Esensoy
Centre for Research in Healthcare Engineering
University of Toronto
Our cross-sector patient flow model is a system dynamics simulation focused on the flow rates of patients between health system sectors, and the feedback structures around them. It takes a whole-system, strategic perspective, and is designed to produce output that captures the direction and magnitude resulting from policy changes around patient pathways and service levels.
The model was developed within a geographically large health region of around one million people. It was constructed based on consultations with four expert panels: health policy leaders, acute, institutional and home and community care. The first panel identified the policy levers targeting flows of patients between healthcare sectors, while the other three panels were engaged to develop causal loop diagrams (CSD) that explained admission and discharge flows of their respective sectors. Qualitative input from these panels was merged with health system data to develop a stock-and-flow structure of the health region. Patients are grouped into cohorts by age, sex, clinical condition, referral source and discharge destination. The model output was validated against admission and discharge data collected over a four year period.
The model has been applied to both qualitative (CSD) and quantitative (stock and flow) decision problems. The CSD model was used by the Ontario Ministry of Health and Long Term Care to test a new slow stream rehab option for complex patients. The model demonstrated several negative unintended consequences and led the policy team to revise their recommendations. The quantitative model has been used to validate the Ontario Stroke Strategy to estimate length of stay improvements. We are currently working with the Ministry to make the tool more widely accessible

Postgraduate Presentations and Social Event

Venue: School of Maths, Cardiff University
Speaker: Various Postgraduate Students
Date: Tuesday, 07 October 2014 at 17:30

Following on from a similar event last year, a number of PhD students will give brief overviews of their research in Operational Research areas. These will cover a range of topics including health, scheduling and routing problems and are based on their ongoing postgraduate research. There will also be an opportunity to meet new students on the MSc in Applied Statistics and Operational Research run by the Cardiff Mathematics Department.

The meeting will be held at the Mathematics Institute, Cardiff University. Tea and coffee will be available from 5.15pm in the Internet Café which is just inside the main entrance to the Mathematics Institute. The talks will commence at 5.30pm in room M/0.40 (ground floor).

The talks will last approximately one hour after which we will go to Koko Gorilaz, a nearby hostelry for networking and free refreshments (meal and drink).

As we need to book the food beforehand, please let me know asap if you plan to attend. Also please let me know if you are a vegetarian or have other dietary requirements. 

Dr Jonathan Thompson

School of Mathematics

Cardiff University

029 20 875524

Visit to Sony, home of Raspberry Pi

Venue: Sony UK Technology Centre, Pencoed
Date: Wednesday, 07 May 2014 at 14:00

SWORDS trip to Sony UK Technology Centre.


Date: Wednesday 7th of May 2014
Time: 2pm.

The Sony UK Technology Centre at Pencoed is the UK home of the Raspberry Pi and is the only facility outside of Japan to manufacture high definition camera units. Cameras and equipment produced at Pencoed can be found at sports stadiums and television studios around the world. It is also home to the Sony Customer Service Centre.  


We need to know well in advance who is attending this event and places are strictly limited to 25. Please contact me ASAP to reserve your place. Please let me know your affiliation and whether you will be taking a car. Their address is: Pencoed Technology Park, Pencoed, CF35 5HZ.


Please note the following:


*                    Closed and flat footwear should be worn. Shorts and hats are not permitted!

*                    The tour will start at 2pm prompt so please arrive well before.

*                    The visit is likely to last around 90 minutes.

*                    Park in the Visitors area and book in at the Security Lodge at the South Gate Entrance

*                    Filming and photography are not permitted

*                    However please be aware that visitors may be filmed by Sony


This is the final meeting of the SWORDS programme for 2013/14. If you have any suggestions for speakers or visits for next year, please let me know.


If you have any other queries please do not hesitate to contact me, Jonathan Thompson, Secretary of SWORDS. Tel: 029 2087 5524. Email:


How Computer Scientists and Performance Analysts are using Information Visualization to advise on the game of Rugby Union

Venue: Cardiff University
Speaker: Rhodri Bown (Welsh Rugby Union) and Matthew Parry (Swansea University)
Date: Tuesday, 18 March 2014 at 17:30 - 18:30

The next SWORDS meeting of the 2013-2014 programme is scheduled for Tuesday the 18th of March 2014. The meeting will be held in room M/0.40 at the Mathematics Institute, Cardiff University. There will be drinks available from 5.15pm in the Internet Café which is just inside the main entrance to the Mathematics Institute. The talk will start at 5.30pm.

 Please contact Jonathan Thompson, tel: 029-20875524



 Highly detailed event annotation is now commonplace in Rugby Union at the Elite level. This explosion of data makes the Performance Analyst’s job of finding significant trends and statistics increasingly difficult and time consuming.

 This talk will discuss how the application of Computer Science and Information Visualization is helping resolve the problem of information overload in the sport, and helping analysts find the edge which can make the difference on the pitch.

OR, Data Science and Analytics: Maximising Value from Big Data

Venue: Cardiff University, School of Mathematics
Speaker: John Hopes, Ernst & Young
Date: Wednesday, 12 February 2014 at 17:30

Note that the AGM will be held from 5.30pm with the talk following at about 5.45pm. 


The OR community has a long history of using analytics to add value, including the development of effective methodologies that ensure implementation.  There is much potential synergy from collaboration between OR, Data Science and Analytics, which will be illustrated via case examples.  The growing role of the OR Society in supporting those working in Analytics and Big Data will also be described.