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NTU researchers optimising container placement on ships

The iStow team comprises (from left) Dr Fan, Dr Lee, Mr Myint and Prof Hsu.

THE planning and optimisation of the placement of containers on ships, known as stowage planning in the shipping industry, is an important procedure in container transportation operations and it can affect shipping lines' operating costs.

With container ships capable of carrying more than 18,000 containers and the increase in worldwide shipping volume, shipping lines are faced with the challenge of generating efficient and stable stowage plans for their vessels as they move between ports.

The Maritime and Port Authority of Singapore (MPA), through its Maritime Innovation and Technology (MINT) Fund, co-funded a collaboration between Nanyang Technological University (NTU) and a local shipping line to develop a system which integrates the container stowage planning with the ship's stability and safety to generate an optimised stowage plan for container vessels.

The system developed has cut down the container allocation planning time from a couple of hours for planning 1,000 to 2,000 containers down to five to seven minutes, with only one to 3 per cent of the containers requiring manual allocation. NTU has been awarded a follow-up project to scale up the system for vessels with more than 10,000 TEUs (twenty-foot equivalent units).

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This is a fine example of using technology to help aid Singapore's productivity and efficiency to meet the new container port capacity aspirations, on the backdrop of a manpower crunch and emerging competition from ports in the region.

"Our project aims to develop a computerised tool called iStow which automatically generates stowage plans for large container vessels," says associate professor Hsu Wen Jing, School of Computer Engineering, College of Engineering at NTU.

His current team members are Fan Rui, Lee Zhuo Qi and Si Thu Myint, who are the backbone of the project having done much of the work on the system with Prof Hsu as facilitator.

Prof Hsu has been actively involved with maritime research and development (R&D) in Singapore since the 1990s. He has participated in the Neptune Orient Lines Fellowship programme.

"As container vessels get larger, handling thousands of containers becomes routine work, so manual stowage planning has become difficult to sustain. The project aims to automate the most time-consuming aspects of their task of generating stowage plans," points out Prof Hsu.

"Thanks to our former and current team members, we had one release of the earlier version of iStow for trial usage. We have just incorporated a new faster scheme for checking constraints, which is a crucial part of the allocation engine. As a result, now it runs faster and produces better stowage plans. We are currently trying to further develop schemes to improve the planning speed and the quality of the planned results."

iStow is able to generate a stowage plan in minutes, explains Prof Hsu. In contrast, generating a plan manually for a small- to medium-sized vessel may take a couple of hours. Devising a stowage plan for a mega vessel is even more demanding, not only because of the larger scale and greater complexity of the problem, but also because of the strict deadline imposed on the planners.

"So, now they can leverage the new tool. The new capability offers two strategic advantages. First, the planners will be able to generate stowage plans for mega vessels at ease and thus be able to handle more orders. Secondly, being able to quickly generate stowage plans also enables the shipping lines to take last-minute orders as a premium service, and better utilise their carrying capacity."

Moreover, experiments show that iStow is able to generate plans that require significantly less ballast water, which is used to balance the ships but is deadweight that consumes fuel. In some cases, the difference is several thousand tonnes of ballast water. Because fuel cost is a large portion of shippers' operating cost, this capability offers competitive advantages to them. Lowering the fuel requirement can also help the shipping lines to become greener with lower CO2 and NOx emissions.

Says Prof Hsu: "A project like this cannot be done by one person alone. We have developed the system through teamwork in several stages. The system was first split up into parts and completed through collaborative efforts. We are thankful for the contributions from everyone involved, including all the former team members."

He emphasises that the aim was not to eliminate the human planners. Instead, iStow is meant to be a tool, much like a calculator, for the human planners, so that they can do their work more effectively and efficiently.

"What iStow really does is to eliminate much of the drudgery of human labour, and enable them to focus more on the other valuable and meaningful services. Planners can use iStow to do the routine work of generating the stowage for the vast majority of the containers within only a few minutes; then they can apply their experience and ingenuity to squeeze in high value-add cargoes or handle special circumstances which are still beyond the current automation technology," explains Prof Hsu.

For those curious about R&D work, he says that it is mostly about ideas and having fun developing them.

"Our work is mainly about ideas: creating, analysing and refining them. There is a lot of fun in this process, especially when you see results evolve and improve from efforts put in. At times we feel frustrated by lack of breakthroughs. But every effort pays off when interesting new concepts emerge to allow improvements. Our work is not always fun. But it is as close as one can get."