We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
from Part IV - Real-Time Software Design Case Studies for Embedded Systems
Published online by Cambridge University Press: 05 March 2016
This chapter describes a concise case study of a Highway Toll Control System in which there are several entry and exit toll booths. Each toll booth is controlled by a real-time embedded subsystem that communicates with a Highway Toll Service subsystem, which receives entry and exit transactions from the toll booths and charges customer accounts. At each toll booth there are multiple sensors and actuators, requiring state dependent entry and exit control. Because entry and exit toll booths are similarly configured and behave in a similar way, this shorter case study concentrates on the design of the entry toll booth. There is less emphasis on the structural modeling in this case study, which has been covered in detail in other case studies.
The problem description is given in Section 23.1. Section 23.2 describes the use case model, and Section 23.3 describes the software system context modeling. Section 23.4 describes the object and class structuring. Section 23.5 describes the state machine model, and Section 23.6 describes the dynamic interaction modeling. Section 23.7 describes the design modeling, which consists of the distributed software design and distributed software deployment, followed by the design of the concurrent task architecture and detailed software design.
PROBLEM DESCRIPTION
A highway toll road has several entry and exit points, at each of which, there is a toll plaza with one or more tollbooths. To use the system, a customer purchases a RFID (radio frequency ID) transponder, which holds the encoded customer account number, from the Highway Toll Service and mounts the transponder on the windshield of the vehicle. The Highway Toll Service maintains customer accounts in a database including owner and vehicle information, and account balance. Customers purchasing a transponder must pay in advance for toll fees by credit card. Accounts are reduced by the toll charge incurred at the end of each trip. The toll charge to be paid depends on the length of the trip and category of the vehicle.
All tollbooths consist of a vehicle arrival sensor (placed fifty feet in front of the tollbooth), a vehicle departure sensor, a traffic light to indicate whether the vehicle has been authorized to pass through the tollbooth, a transponder detector, and a camera.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
