Rekayasa Perangkat Lunak 2 (IN043): Pertemuan 9. Human Computer Interaction Design and Physical Architecture Layer Design

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1 Rekayasa Perangkat Lunak 2 (IN043): Pertemuan 9 Human Computer Interaction Design and Physical Architecture Layer Design

2 Principes of User Interface Design

3 Layout The areas and information within areas should have a natural intuitive flow to minimize the users movement from one area to the next. Most software designed for personal computers follows the standard Windows or Macintosh approach for screen design. The screen is divided into three boxes. The top box is the navigation area, through which the user issues commands to navigate through the system. The bottom box is the status area, which displays information about what the user is doing. The middle and largest box is used to display reports and present forms for data entry. In many cases (particularly on the Web), multiple layout areas are used, for instance 5 areas which are divided into: The top area provides the standard Internet Explorer navigation and command controls that change the contents of the entire system. The navigation area on the left edge navigates between sections and changes all content to its right. The other two navigation areas at the top and bottom of the page provide other ways to navigate between sections. The content in the middle of the page displays the results (i.e., a report on a book) and also provides additional navigation within the page about this book.

4 Multiple Navigation Areas

5 Content Awareness Content awareness refers to the ability of an interface to make the user aware of the information it contains with the least amount of effort on the user s part. All parts of the interface, whether navigation, input, or output, should provide as much content awareness as possible, but it is particularly important for forms or reports that are used quickly or irregularly (e.g., a Web site).

6 Flow Between Interface Section Vertical Flow Horizontal Flow

7 Aesthetics Aesthetics refers to designing interfaces that are pleasing to the eye. Interfaces do not have to be works of art, but they do need to be functional and inviting to use. In most cases, less is more, meaning that a simple, minimalist design is the best. In general, novice or infrequent users of an interface, whether on a screen or on paper, prefer interfaces with low density, often one with a density of less than 50 percent (i.e., less than 50 percent of the interface occupied by information). More experienced users prefer higher densities, sometimes approaching 90 percent occupied because they know where information is located and high densities reduce the amount of physical movement through the interface.

8 Example Its density is too high; It has too much information packed into a too-small space with too little white space. Although it may be efficient to save paper by using one page, not two, it is not effective for many users.

9 Use Experience User experience can essentially be broken down into two levels: those with experience and those without. Interfaces should be designed for both types of users. Novice users usually are most concerned with ease of learning how quickly they can learn new systems. Expert users are usually most concerned with ease of use how quickly they can use the system once they have learned how to use it.

10 Consistency Consistency in design is probably the single most important factor in making a system simple to use because it enables users to predict what will happen. When interfaces are consistent, users can interact with one part of the system and then know how to interact with the rest, aside, of course, from elements unique to those parts. Consistency usually refers to the interface within one computer system, so that all parts of the same system work in the same way.

11 Minimizing User Effort Interfaces should be designed to minimize the amount of effort needed to accomplish tasks. This means using the fewest possible mouse clicks or keystrokes to move from one part of the system to another. Most interface designers follow the three-clicks rule: users should be able to go from the start or main menu of a system to the information or action they want in no more than three mouse clicks or three keystrokes.

12 Elements of the Physical Architecture Layer Architectural Component Hardware: client computers, servers, and the network Software: data storage, data access logic, application logic, presentation logic Server-based Architecture: server performing all four application functions (data storage, data access logic, application logic, presentation logic). The clients merely captured keystrokes and sent them to the server for processing and accepted instructions from the server on what to display. Client-based Architecture: the clients are personal computers on a local area network (LAN), and the server computer is a server on the same network. Client-server Architecture: attempt to balance the processing between the client and the server by having both do some of the application functions.

13 Client-Server Tiers two-tiered architecture: The server is responsible for the data, and the client is responsible for the application and presentation. three-tiered architecture: The software on the client computer is responsible for presentation logic, an application server (or servers) is responsible for the application logic, and a separate database server (or servers) is responsible for the data access logic and data storage. n-tiered architecture: The client is responsible for presentation, database servers are responsible for the data access logic and data storage, and the application logic is spread across two or more different sets of servers.

14 Example of Four-Tiered Client-Server Architecture

15 Distributed Object Computing (1) Distributed objects computing (DOC) represents a software layer that goes between the clients and servers; hence, it is known as middleware. Middleware supports the interaction between objects in a distributed computing environment. Furthermore, middleware treats the actual physical network architecture in a transparent manner. This allows the developer to focus on the development of the application and ignore the peculiarities of a specific distributed environment.

16 Distributed Object Computing (2) DOC allows the developer to simply concentrate on the users, objects, and methods of an application instead of worrying about which server contains which set of objects. The client object simply requests the network to locate and execute the server object s method. Only the middleware must be made aware of the new addresses of the server objects. However, because middleware adds an additional layer between the clients and servers, it can reduce the efficiency of the application.

17 Characteristics of Computing Architecture

18 Nonfunctional Requirements and Their Impacts for Architecture Design

19 Example of Deployment Diagram Representation of Low-Level Network Model

20 Example of Deployment Diagram of Layers for Internet Sales System

21 Exercise Build interface design and also physical architecture layer design according to your group cases.

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