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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.

## 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.

## 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.

## Simulation

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

## Assumptions

Pump Price HK\$23.24 / Litre

Toyota Hiace 5th gen

fuel consumption

11.4km/litre

## Cost

Manual route (22km):

\$22/11.4x23.24 = ~\$45

Most optimal route (18.3km):

\$18.3/11.4x23.24 = ~\$37

Difference:

\$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%

Time:

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

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