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Collection Logistics System

What is Travelling Salesman Problem?

Travelling Salesman Problem is a problem that cannot be solved, but can be optimized only. Given a list of location or destination points, the travelling salesman has to find the shortest possible route that visits each point exactly once and returns to the starting point.


How is it related to RealCycle?

One of the main goals of RealCycle is to reduce transport costs and additional human resources. Therefore, an efficient and optimal way of collecting plastic bottles is needed.

To achieve this aim, there will be a notification system in the machine, notifying RSPs when the bin is 80% full.

Recycling Bin

How does it affect recycling?

RSPs collect recyclables from recycling bins regularly in common practice. However, there is no smart system notifying them, which leads to inability to determine whether the bins are full or empty, which may further result in waste of transport costs.

Recycling Plastic Bottles

How does RealCycle address this issue?

A sensor will be used to detect the fullness of the bin, which can be shown real-time to RSPs.

The location of the full bins are inputted into a program, where the shortest path between pairs of locations will first be computed using Google Maps to form a distance matrix. Then, this distance matrix will be provided to a Traveling Salesman Problem solver to find the shortest path to traverse all locations of the full bins.

Screenshot 2023-04-12 022625.png
Modern Architecture


The following simulation is done in Tseung Kwan O region, where most bins are located in

Large shopping malls that serve public housing estates and private housing estates in

Tseung Kwan O,

Hang Hau,

Tiu Keng Leng,

Po Lam


Shell FuelSave Unleaded

Pump Price HK$23.24 / Litre

Toyota Hiace 5th gen

fuel consumption



Manual route (22km):

$22/11.4x23.24 = ~$45

Most optimal route (18.3km):

$18.3/11.4x23.24 = ~$37


$45-37 = $8 per travel

Human Resources

With notification system and collection map planned out, RSPs can collect recyclables with efficiency without going to unfilled bins

Saved Time & Distance

Percentage change in Distance:

(22-18.3)/22x100% = ~17%


(78-46)/78x100% = 41%

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