IT323 - Software Engineering 2 1

Tutorial 2

What is 1-Tier and 2-Tier Architectures?

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1-Tier Architecture is the simplest, single tier on single user, is the equivalent of running an application on a personal computer. All the required component to run the application are located within local or shared drive.

For example All resources associated with the computer (tape and disk drives, printers etc.) were attached to the Mainframe computer. This is the simplest, but also the least secure. Since users have direct access to the files, they could accidentally move, modify, or even worse, delete the file by accident or on purpose. because they are not part of a network, they are useless for designing web applications.

There is also usually an issue when multiple users access the same file at the same time: In many cases only one can edit the file

So 1-tier architecture is simple and cheap, but usually unsecured and data can easily be lost if you are not careful.

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2-Tier architecture is also called Client-Server architecture because of the two components: The client that runs the application and the server that handles the database back-end.

When the client starts it establishes a connection to the server and communicates as needed with the server while running the client.

The client computer usually can’t see the database directly and can only access the data by starting the client. This means that the data on the server is much more secure. Now users are unable to change or delete data unless they have specific user rights to do so.

For Example: the client (on the personal computer) would connect to a central computer (server) and request data. This model is also quite easy to implement.

All you need is an RDBMS, such as MS-SQL Server 2000, running on Windows 2000 Server and a PC running TCP/IP. You application connects to the database server and requests data. The server just returns the data requested.

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The client-server solution also allows multiple users to access the database at the same time as long as they are accessing data in different parts of the database. One other huge benefit is that the server is processing data that allows the client to work on the presentation and business logic only. This mean that the client and the server is sharing the workload and by scaling the server to be more powerful than the client, you are usually able to load many clients to the server allowing more users to work on the system at the same time.

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Explain how "Thick-client" and "Thin-client" can be implemented in 3-tier architecture?

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This architecture involves one more layer called the business logic tier, service tier or middle tier (layer). In the client-server solution the client was handling the business logic and that makes the client “thick”. A thick client means that it requires heavy traffic with the server, thus making it difficult to use over slower network connections like Internet and Wireless (LTE, 3G, or Wi-Fi). By introducing the middle layer, only little communication is needed between the client and the middle tier making the client “thin” or “thinner”

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Suggest best architectural design for the following case studies:

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A Real-Time Fire Detection System (RTFDS): Every year, thousands of people die in the home fires. There are a lot of reasons for these fires like short circuits in electricity, children who play with match sticks, etc. Fire can easily grow up in room conditions because there are a lot of flammable objects in homes like carpets, curtains, wooden chairs, tables, etc. To reduce damage, we have to immediately try to extinguish fire as soon as possible. The fire detection system is aims to protect target person based on computer vision approaches. When fire is detected, alarm sound begins to play with high volume. By this alarm sound, if there is a person in the next rooms, he or she can protect target person.

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The suggested architecture styles used for organizing the RTFDS is a hybrid architecture style, consists of layered architecture style as the whole system structure and detailed into pipe and filter architecture style (Pipeline). Due to the need of information security and privilege access to the database, a layered methodology has been chosen as the most applicable style to represent the whole system organization. Furthermore, The pipe and filter architecture is an appropriate choice for the system's main functionalities because of the fact that this architecture" is a model of run-time organization of system where process their inputs and produce outputs" Moreover, the RTFDS has a lot of image processing where the pipe and filter architecture is common style for data processing systems.

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SYSTEM'S OVERALL ARCHITECTURE AS LAYERED STYLE:

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IMAGE PROCESSING PIPE AND FILTER STYLE:

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My Budget Book Mobile Application

My Budget Book is not just an ordinary expense management program. This app helps you keep track of you expenditures and earnings and manage your money more effectively. Use the individual transfers and standing orders feature to get an idea of your expenses over the next couple of months and see how much money you have available to spend. The app also gives you a graphical overview of the information, making it easier to plan (larger) purchases over the up-coming months. Also, the application can securely synchronize between your account in the application and your bank account. We all know what it feels like to want to buy something but not know whether you can afford it. Use My Budget Book to see your current balance as well as how many bills you have to pay before the end of the month.

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Main features: • Easy access. An internet connection required only for synchronous

communicating with bank account for the user. • See each month’s balance and all previous balancing. • Get more flexibility by selecting what day you want the month to start on. • Visualize the statistics as a table or graph and see where your money has

gone by categorizing all earnings and expenses. • Filter your earnings and expenses according to months, quarters or whole

years, as well as any other criteria. • Sort your transactions by date, amount, title or category. • Use the powerful search function to look for specific expenses and/or time

periods. • Carry your balance over into the next month. • Manage standing orders so you can plan ahead for the upcoming months. • Use the watch-list to monitor important transactions.

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Repository pattern for the whole system. Layered pattern for the synchronizing component (because it will communicate with the bank – it needs security)

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MOFA KSA (Ministry of Foreign Affairs KSA)

An application for the MOFA services. Please read the description from your mobile store.

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3-Tier pattern: The data, middleware, front-end.