Problem Description

Overview

The Smart Home contractors "Smart Builders" we saw in the previous assignments have now landed an actual project. They are asked to install a full Heating, Ventilation and Air Conditioning (HVAC) solution for a small lab space owned by the water quality testing lab company "Water Bros Inc.". The lab space consists of:

• A foyer at the entrance where the reception is

• 2 labs hosting sensitive measuring and analysis equipment,

• 2 office spaces with cubicles for the technicians and doctors,

• a board and meeting room,

• a mail room and

• a sample storage room

Smart Builders must deploy their HVAC devices so that the temperature is always controlled. It turns out that their clients had very specific requirements which they presented in detail below.

Specifically they want room temperature to be reliably sensed 99,999% of the time, to be able to detect faulty components (temperature sensors, AC, Furnace) within 1 minute and detect temperature changes from any sensor within 20 seconds. They also want room temperature readings to be within a 0.5 Celsius accuracy. At the same time they need to stay within budget because their own investors areconcerned with cost-effectiveness. Finally, they want the architecture to be highly maintainable, and specifically they want to be able to switch temperature sensor and actuator (HVAC/Furnace) vendors.

Design

Design Concept

Smart Builders thought carefully about Water Bros' problem. They propose a solution that has the following characteristics:

• There are four independent furnaces and four independent ACs in the lab.

1. One Furnace and one AC unit for each of the two labs.
2. One Furnace and one AC unit for the sample room.
3. One Furnace and one AC unit for the rest of the rooms (utilizing existing air ducts).

• Each of the labs and the sample room must have several temperature sensors.
• One thermostat controls all the rooms.

Technical Considerations

The components that Smart Builders consider to use are:

• Furnace to be used is SaharaFurnaceLL50.

• AC used is PolarFrostB15 by Polar Works Inc.

• Thermostat Interface is ThermoSetX19.

• Their custom-made Controller.

All the above fully implement the SSDCS specification. All the above (AC, Furnace, Thermostat, Controller) are or are controlled through an attached Raspberry Pi connected through Wifi or Ethernet and allowing access to functionality through Java RMI. For temperature sensors, Smart Builders are considering two possibilities:

• OmniTempSensorXS3 [$200 each], which measures temperature in one location. The sensor is also attached to a Rasberry board which can, in turn, connect through Wifi or Ethernet and Java RMI. The sensor offers correct readings (i.e., is available) 99% of the time.

• SeriousTempBus from Serious Temp Inc. [$150 each] come with a controller (of proprietary board and operating system implementing full TCP/IP stack) and one (1) passive battery operated sensor detached from the controller and regularly transmitting temperature information to the controller via a 800 Mzh frequency and using a proprietary wireless protocol. SeriousTempBus does not implement SSDCS, but can be controlled through commands over TCP/IP connections (pretty much like HTTP or IMAP); they call the protocol TAP (Temperature Awareness Protocol). The sensor offers correct readings (is available) 99% of the time.

Specifically they want room temperature to be reliably sensed 99,999% of the time, to be able to detect faulty components (temperature sensors, AC, Furnace) within 1 minute and detect temperature changes from any sensor within 20 seconds. They also want room temperature readings to be within a 0.5 Celsius accuracy. At the same time they need to stay within budget because their own investors areconcerned with cost-effectiveness. Finally, they want the architecture to be highly maintainable, and specifically they want to be able to switch temperature sensor and actuator (HVAC/Furnace) vendors.

What to Do

1. Prior to beginning you will need to familiarize yourselves with technologies mentioned above.

• Java RMI allows use of classes that reside on a different computer as if they were local. Java RMI allows the presence of a network to be transparent to the users.Review this tutorial.

• Raspberry Pi are small computers running a lightweight version of Linux. They implementthe full TCP/IP stackand are able to connect to Wifi, Ethernet and Bluetooth. They are widely used for building controllers (from TV Streaming boxes to Smart Thermostats).Review this page.

• HTTP, IMAP, FTP etc. are services that run on top of TCP/IP. The requester simply sends commands to the server, and the latter responds. Checkthis out.

2. Make design decisions that allow Water Bros achieve their quality objectives (accuracy, fault detection and tolerance). Your design decisions include:

• The choice between SeriousTempBus and OmniTempSensorXS3 for each room and where they are placed.
• How many controllers, sensors and in what configurations should they be.
• Decide how you are going to support the availability requirements for sensors.

3. Go to the Architecture Definition Document template below and produce descriptions and models that describe your work above.

ARCHITECTURAL DEFINITION DOCUMENT

1. Summary of what this document is about

2. Summary of the problem and the proposed solution

QUALITY SCENARIOS:The requirements given to you state several quality requirements. Devise three quality scenarios that exemplify these requirements on the topics of availability, performance (accuracy) and maintainability.

ARCHITECTURAL PATTERNS AND TACTICS

Focus again on the qualityrequirements identified in the above scenarios or in the requirements. Describe what architectural patterns you are using to:

1. Detect faults and mitigate them to achieve the availability targets.
2. Ensure accuracy of measurements.
3. Achieve prompt temperature change detection.
4. Ensure replaceability of sensor and actuator vendors.
5. Attain a quality of your choosing.

Functional Viewpoint

VIEW

Produce a component diagram describing the relationships between components in your solution. Ensure you document architectural interfaces properly:

PRINCIPLES APPLIED

Using annotations (UML Notes) inside your diagram, describe how your solution embodies design and/or architectural principles, tactics, and patterns for meeting the requirements specified above:

DEPLOYMENT VIEWPOINT

VIEW

Produce a deployment diagram describing the chosen deployment approach

PRINCIPLES APPLIED

Using annotations (UML Notes) inside your diagram, describe how your solution embodies design and/or architectural principles, tactics, and patterns for meeting the requirements specified above