This document discusses key concepts in software design engineering including analysis models, design models, the programmer's approach versus best practices, purposes of design, quality guidelines, design principles, fundamental concepts like abstraction and architecture, and specific design concepts like patterns, modularity, and information hiding. It emphasizes that design is important for translating requirements into a quality software solution before implementation begins.
UML (Unified Modeling Language) is a standard modeling language used to document and visualize the design of object-oriented software systems. It was developed in the 1990s to standardize the different object-oriented modeling notations that existed. UML is based on several influential object-oriented analysis and design methodologies. It includes diagrams for modeling a system's structural and behavioral elements, and has continued to evolve with refinements and expanded applicability. Use case diagrams are one type of UML diagram that are used to define system behaviors and goals from the perspective of different user types or external entities known as actors.
This document discusses the Think Pair Share activity and principles of cohesion and coupling in software design. It provides definitions and examples of different types of coupling (data, stamp, control, etc.) and levels of cohesion (functional, sequential, communicational, etc.). The key goals are to minimize coupling between modules to reduce dependencies, and maximize cohesion so elements within a module are strongly related and focused on a single task. High cohesion and low coupling lead to components that are more independent, flexible, and maintainable.
Activity diagrams show the flow and sequence of activities in a system by depicting actions, decisions, and parallel processes through graphical symbols like activities, transitions, decisions, and swimlanes. They are used to model workflows, use cases, and complex methods by defining activities, states, objects, responsibilities, and connections between elements. Guidelines are provided for creating activity diagrams, such as identifying the workflow objective, pre/post-conditions, activities, states, objects, responsibilities, and evaluating for concurrency.
UML component diagrams describe software components and their dependencies. A component represents a modular and replaceable unit with well-defined interfaces. Component diagrams show the organization and dependencies between components using interfaces, dependencies, ports, and connectors. They can show both the external view of a component's interfaces as well as its internal structure by nesting other components or classes.
Object oriented concepts can be summarized in 3 sentences:
Objects have state, behavior, and identity. State represents the properties and values of an object, behavior is defined by the operations or methods that can be performed on an object, and identity uniquely distinguishes one object from all others. Key concepts in object orientation include abstraction, encapsulation, modularity, hierarchy, polymorphism, and life span of objects. These concepts help organize programs through the definition and use of classes and objects.
Software testing techniques document discusses various software testing methods like unit testing, integration testing, system testing, white box testing, black box testing, performance testing, stress testing, and scalability testing. It provides definitions and characteristics of each method. Some key points made in the document include that unit testing tests individual classes, integration testing tests class interactions, system testing validates functionality, and performance testing evaluates how the system performs under varying loads.
Software requirement engineering bridges the gap between system engineering and software design. It involves gathering requirements through elicitation techniques like interviews and facilitated application specification technique (FAST), analyzing requirements, modeling them, specifying them in documents like use cases, and reviewing the requirements specification. Quality function deployment translates customer needs into technical requirements. Rapid prototyping helps validate requirements by constructing a partial system implementation using tools like 4GLs, reusable components, or formal specification languages. The software requirements specification document is produced at the end of analysis and acts as a contract between developers and customers.
The document discusses various techniques for analysis modeling in software engineering. It describes the goals of analysis modeling as providing the first technical representation of a system that is easy to understand and maintain. It then covers different types of analysis models, including flow-oriented modeling, scenario-based modeling using use cases and activity diagrams, and class-based modeling involving identifying classes, attributes, and operations. The document provides examples and guidelines for effectively utilizing these modeling approaches in requirements analysis.
UML (Unified Modeling Language) is a standard modeling language used to document and visualize the design of object-oriented software systems. It was developed in the 1990s to standardize the different object-oriented modeling notations that existed. UML is based on several influential object-oriented analysis and design methodologies. It includes diagrams for modeling a system's structural and behavioral elements, and has continued to evolve with refinements and expanded applicability. Use case diagrams are one type of UML diagram that are used to define system behaviors and goals from the perspective of different user types or external entities known as actors.
This document discusses the Think Pair Share activity and principles of cohesion and coupling in software design. It provides definitions and examples of different types of coupling (data, stamp, control, etc.) and levels of cohesion (functional, sequential, communicational, etc.). The key goals are to minimize coupling between modules to reduce dependencies, and maximize cohesion so elements within a module are strongly related and focused on a single task. High cohesion and low coupling lead to components that are more independent, flexible, and maintainable.
Activity diagrams show the flow and sequence of activities in a system by depicting actions, decisions, and parallel processes through graphical symbols like activities, transitions, decisions, and swimlanes. They are used to model workflows, use cases, and complex methods by defining activities, states, objects, responsibilities, and connections between elements. Guidelines are provided for creating activity diagrams, such as identifying the workflow objective, pre/post-conditions, activities, states, objects, responsibilities, and evaluating for concurrency.
UML component diagrams describe software components and their dependencies. A component represents a modular and replaceable unit with well-defined interfaces. Component diagrams show the organization and dependencies between components using interfaces, dependencies, ports, and connectors. They can show both the external view of a component's interfaces as well as its internal structure by nesting other components or classes.
Object oriented concepts can be summarized in 3 sentences:
Objects have state, behavior, and identity. State represents the properties and values of an object, behavior is defined by the operations or methods that can be performed on an object, and identity uniquely distinguishes one object from all others. Key concepts in object orientation include abstraction, encapsulation, modularity, hierarchy, polymorphism, and life span of objects. These concepts help organize programs through the definition and use of classes and objects.
Software testing techniques document discusses various software testing methods like unit testing, integration testing, system testing, white box testing, black box testing, performance testing, stress testing, and scalability testing. It provides definitions and characteristics of each method. Some key points made in the document include that unit testing tests individual classes, integration testing tests class interactions, system testing validates functionality, and performance testing evaluates how the system performs under varying loads.
Software requirement engineering bridges the gap between system engineering and software design. It involves gathering requirements through elicitation techniques like interviews and facilitated application specification technique (FAST), analyzing requirements, modeling them, specifying them in documents like use cases, and reviewing the requirements specification. Quality function deployment translates customer needs into technical requirements. Rapid prototyping helps validate requirements by constructing a partial system implementation using tools like 4GLs, reusable components, or formal specification languages. The software requirements specification document is produced at the end of analysis and acts as a contract between developers and customers.
The document discusses various techniques for analysis modeling in software engineering. It describes the goals of analysis modeling as providing the first technical representation of a system that is easy to understand and maintain. It then covers different types of analysis models, including flow-oriented modeling, scenario-based modeling using use cases and activity diagrams, and class-based modeling involving identifying classes, attributes, and operations. The document provides examples and guidelines for effectively utilizing these modeling approaches in requirements analysis.
This document provides an overview of use case diagrams and use cases. It defines what a use case is, including that it captures a user's interaction with a system to achieve a goal. It describes the key components of a use case diagram, including actors, use cases, and relationships between use cases like generalization, inclusion, and extension. An example use case diagram for a money withdrawal from an ATM is presented to illustrate these concepts. Guidelines for documenting use cases with descriptions of flows, exceptions, and other details are also provided.
The document discusses component-based software engineering and defines a software component. A component is a modular building block defined by interfaces that can be independently deployed. Components are standardized, independent, composable, deployable, and documented. They communicate through interfaces and are designed to achieve reusability. The document outlines characteristics of components and discusses different views of components, including object-oriented, conventional, and process-related views. It also covers topics like component-level design principles, packaging, cohesion, and coupling.
The document discusses use case diagrams in object oriented design and analysis. It defines use cases as descriptions of system functionality from a user perspective. Use case diagrams depict system behavior, users, and relationships between actors, use cases, and other use cases. The key components of use case diagrams are described as actors, use cases, the system boundary, and relationships. Common relationships include association, extend, generalization, uses, and include. An example use case diagram for a cellular telephone is provided to illustrate these concepts.
The document discusses requirements modeling and analysis modeling in software engineering. It provides information on:
1) The different types of models that can be created during requirements modeling, including requirements models, design models, scenario-based models, data models, class-based models, flow-oriented models, and behavioral models.
2) The purposes of requirements modeling, which include representing customer requirements, gaining a better understanding of the system, and providing information to help with system design and development.
3) Key principles of requirements modeling, such as representing the information, functional, and behavioral domains of the system and partitioning models in a layered/hierarchical way.
4) Specific modeling techniques like scenario-based modeling, data
The document discusses key concepts and principles of software design. It begins by defining design as a blueprint for solving problems specified in requirements. Good design implements all requirements, provides a readable guide, and gives a complete picture of the software. The design process has two levels - top-level design of modules and interfaces and detailed design of module internals. The document then covers fundamental design concepts like abstraction, refinement, modularity, architecture, partitioning, data structures, procedures, information hiding, and functional independence. It provides examples and guidelines for applying these concepts to create a high-quality design.
This document discusses structural modeling and analysis in software engineering. It defines key concepts like objects, classes, inheritance, encapsulation, and polymorphism. It also covers modeling techniques like UML notation for class diagrams, associations between classes, aggregation, composition, constraints, and domain modeling processes. The overall summary is:
Structural modeling shows how different entities ("things") are related to each other. It involves identifying objects and classes, defining their attributes and operations, and specifying relationships like generalization, aggregation, and associations between classes. UML notation is commonly used to diagram class structures and relationships. The domain modeling process aims to develop class models that describe real-world entities and their interactions within a problem domain.
The document discusses component-level design which occurs after architectural design. It aims to create a design model from analysis and architectural models. Component-level design can be represented using graphical, tabular, or text-based notations. The key aspects covered include:
- Defining a software component as a modular building block with interfaces and collaboration
- Designing class-based components following principles like open-closed and dependency inversion
- Guidelines for high cohesion and low coupling in components
- Designing conventional components using notations like sequence, if-then-else, and tabular representations
The document discusses component-level design which occurs after architectural design. It aims to create a detailed design model from previous models. Key points:
- A software component is a modular building block with well-defined interfaces and collaboration. Components can be viewed as classes, modules, or reusable processes.
- Effective design follows principles like open-closed and dependency inversion. Components have well-defined dependencies and inheritance relationships.
- Class-based components are designed for high cohesion and low coupling. Conventional components are derived from analysis models and decompose problems into logical modules.
The document discusses various concepts and methodologies related to software design including design specification modules, design languages like use case diagrams and class diagrams, fundamental design concepts like abstraction and modularity, modular design methods and criteria for evaluation, control terminology, effective modular design principles of high cohesion and low coupling, design heuristics, and ten heuristics for user interface design.
Object-oriented analysis and design (OOAD) uses visual modeling techniques like the Unified Modeling Language (UML) to analyze and design systems based on interacting objects. UML captures system elements and facilitates specification and visualization. It includes static diagrams for non-changing characteristics and dynamic diagrams for changing behaviors. The goal of OOAD and UML is to integrate analysis and development teams through defined processes and modeling.
This document summarizes a software engineering presentation on software requirement analysis. The presentation was assigned by Dr. Muhammad Idrees to group number 5, consisting of 4 members. It introduced software requirement analysis, the major areas of effort including requirement gathering and analysis techniques like meetings, interviews, FAST and QFD. It described the principles of requirement analysis and how requirements are modeled. It explained prototyping and the contents of a software requirements specification document.
This document discusses modeling and analysis techniques used in decision support systems (DSS). It covers various categories of DSS models including optimization, simulation, and predictive models. It also describes static and dynamic analysis, decision making under certainty, risk, and uncertainty. Different modeling approaches like mathematical modeling, simulation, and heuristics are explained.
This document provides definitions and information about software architecture and specifications. It defines architectural models as the top-level structure and organizing principles of a system. Specifications are described at different levels: A-level from the customer perspective, B-level from the developer perspective describing logical components. Requirements are decomposed into processes and data flows during analysis and composed into modules and classes during design. Specifications should be unambiguous and testable.
Object oriented analysis emphasizes investigating the problem domain to identify relevant objects and their relationships. The key goals are to define relevant classes and their attributes, operations, relationships, and behaviors through iterative refinement. Various analysis methods take different approaches, but generally involve use case modeling, class modeling, and behavior modeling.
The document discusses use case diagrams in UML modeling. It defines key components of use case diagrams including use cases, actors, the system boundary, and relationships like include, extend, and generalization. It provides examples of how to construct a use case diagram based on system functions and user goals. Specific use case diagram examples shown include an online ordering system and a vending machine.
Function-oriented design views a system as modules with clearly defined behaviors that interact to meet requirements. It discusses various design methodologies including structured design methodology which involves identifying inputs/outputs and transformations, and factoring modules into submodules. Design quality can be evaluated using metrics related to cohesion, coupling, complexity, and information flow.
Design and Implementation in Software EngineeringKourosh Sajjadi
These slides were presented to the software engineering class held in IAUN. The main context is provided from the "Software Engineering" book authored by Sommerville.
Most of the icons used in the slides are provided in the flaticon.com website.
Thanks to our professor Habib Seifzadeh.
A cooperation with Mohammad Mostajeran.
Use case diagrams describe interactions between actors and a system to accomplish goals. A use case diagram typically includes:
1) Actors that interact with the system from outside, such as users or other systems. Common actor types are primary actors whose goals are fulfilled by the system and supporting actors that provide services.
2) Use cases that represent functions or tasks performed by the system. They are connected to relevant actors and may have relationships like include and extend.
3) Relationships between use cases like include, which shows a use case incorporating another, and extend, where a use case optionally extends another.
Use case diagrams provide an overview of a system's functions and how outside actors interact with them at a
The document discusses the software development life cycle (SDLC) which includes 8 phases: system conception, requirement gathering, system design, class design, implementation, testing, deployment, and maintenance. It states that requirement gathering focuses on what must be done without how, and involves domain and application analysis. Domain analysis emphasizes real-world objects to understand the problem domain. The implementation phase is the longest as it involves coding the requirements.
The document provides an overview of basic software design concepts including the design process, quality factors, techniques, methodologies, approaches, models, modularization, data design, guidelines, verification, and key issues. It discusses that software design is an iterative process of translating requirements into a system blueprint. The design process involves informal to more formal designs. Quality factors, architectures, technologies, styles, and decomposition are considered. Top-down and bottom-up approaches are described. Modularization, data design, and guidelines are covered. Verification ensures the design is valid before implementation. Key issues are areas most prone to mistakes.
Object modeling involves identifying important objects (classes) within a system and defining their attributes, operations, and relationships. During object modeling, classes are identified based on system requirements and domain concepts. Key activities include class identification, defining class attributes and methods, and determining associations between classes. Object modeling results in a visual representation of classes and their relationships in class and other diagrams.
This document discusses software quality and metrics. It defines software quality as conformance to requirements, standards, and implicit expectations. It outlines ISO 9126 quality factors like functionality, reliability, usability, and maintainability. It describes five views of quality: transcendental, user, manufacturing, product, and value-based. It also discusses types of metrics like product, process, and project metrics. Product metrics measure characteristics like size, complexity, and quality level. The document provides guidelines for developing, collecting, analyzing, and interpreting software metrics.
This document provides an overview of use case diagrams and use cases. It defines what a use case is, including that it captures a user's interaction with a system to achieve a goal. It describes the key components of a use case diagram, including actors, use cases, and relationships between use cases like generalization, inclusion, and extension. An example use case diagram for a money withdrawal from an ATM is presented to illustrate these concepts. Guidelines for documenting use cases with descriptions of flows, exceptions, and other details are also provided.
The document discusses component-based software engineering and defines a software component. A component is a modular building block defined by interfaces that can be independently deployed. Components are standardized, independent, composable, deployable, and documented. They communicate through interfaces and are designed to achieve reusability. The document outlines characteristics of components and discusses different views of components, including object-oriented, conventional, and process-related views. It also covers topics like component-level design principles, packaging, cohesion, and coupling.
The document discusses use case diagrams in object oriented design and analysis. It defines use cases as descriptions of system functionality from a user perspective. Use case diagrams depict system behavior, users, and relationships between actors, use cases, and other use cases. The key components of use case diagrams are described as actors, use cases, the system boundary, and relationships. Common relationships include association, extend, generalization, uses, and include. An example use case diagram for a cellular telephone is provided to illustrate these concepts.
The document discusses requirements modeling and analysis modeling in software engineering. It provides information on:
1) The different types of models that can be created during requirements modeling, including requirements models, design models, scenario-based models, data models, class-based models, flow-oriented models, and behavioral models.
2) The purposes of requirements modeling, which include representing customer requirements, gaining a better understanding of the system, and providing information to help with system design and development.
3) Key principles of requirements modeling, such as representing the information, functional, and behavioral domains of the system and partitioning models in a layered/hierarchical way.
4) Specific modeling techniques like scenario-based modeling, data
The document discusses key concepts and principles of software design. It begins by defining design as a blueprint for solving problems specified in requirements. Good design implements all requirements, provides a readable guide, and gives a complete picture of the software. The design process has two levels - top-level design of modules and interfaces and detailed design of module internals. The document then covers fundamental design concepts like abstraction, refinement, modularity, architecture, partitioning, data structures, procedures, information hiding, and functional independence. It provides examples and guidelines for applying these concepts to create a high-quality design.
This document discusses structural modeling and analysis in software engineering. It defines key concepts like objects, classes, inheritance, encapsulation, and polymorphism. It also covers modeling techniques like UML notation for class diagrams, associations between classes, aggregation, composition, constraints, and domain modeling processes. The overall summary is:
Structural modeling shows how different entities ("things") are related to each other. It involves identifying objects and classes, defining their attributes and operations, and specifying relationships like generalization, aggregation, and associations between classes. UML notation is commonly used to diagram class structures and relationships. The domain modeling process aims to develop class models that describe real-world entities and their interactions within a problem domain.
The document discusses component-level design which occurs after architectural design. It aims to create a design model from analysis and architectural models. Component-level design can be represented using graphical, tabular, or text-based notations. The key aspects covered include:
- Defining a software component as a modular building block with interfaces and collaboration
- Designing class-based components following principles like open-closed and dependency inversion
- Guidelines for high cohesion and low coupling in components
- Designing conventional components using notations like sequence, if-then-else, and tabular representations
The document discusses component-level design which occurs after architectural design. It aims to create a detailed design model from previous models. Key points:
- A software component is a modular building block with well-defined interfaces and collaboration. Components can be viewed as classes, modules, or reusable processes.
- Effective design follows principles like open-closed and dependency inversion. Components have well-defined dependencies and inheritance relationships.
- Class-based components are designed for high cohesion and low coupling. Conventional components are derived from analysis models and decompose problems into logical modules.
The document discusses various concepts and methodologies related to software design including design specification modules, design languages like use case diagrams and class diagrams, fundamental design concepts like abstraction and modularity, modular design methods and criteria for evaluation, control terminology, effective modular design principles of high cohesion and low coupling, design heuristics, and ten heuristics for user interface design.
Object-oriented analysis and design (OOAD) uses visual modeling techniques like the Unified Modeling Language (UML) to analyze and design systems based on interacting objects. UML captures system elements and facilitates specification and visualization. It includes static diagrams for non-changing characteristics and dynamic diagrams for changing behaviors. The goal of OOAD and UML is to integrate analysis and development teams through defined processes and modeling.
This document summarizes a software engineering presentation on software requirement analysis. The presentation was assigned by Dr. Muhammad Idrees to group number 5, consisting of 4 members. It introduced software requirement analysis, the major areas of effort including requirement gathering and analysis techniques like meetings, interviews, FAST and QFD. It described the principles of requirement analysis and how requirements are modeled. It explained prototyping and the contents of a software requirements specification document.
This document discusses modeling and analysis techniques used in decision support systems (DSS). It covers various categories of DSS models including optimization, simulation, and predictive models. It also describes static and dynamic analysis, decision making under certainty, risk, and uncertainty. Different modeling approaches like mathematical modeling, simulation, and heuristics are explained.
This document provides definitions and information about software architecture and specifications. It defines architectural models as the top-level structure and organizing principles of a system. Specifications are described at different levels: A-level from the customer perspective, B-level from the developer perspective describing logical components. Requirements are decomposed into processes and data flows during analysis and composed into modules and classes during design. Specifications should be unambiguous and testable.
Object oriented analysis emphasizes investigating the problem domain to identify relevant objects and their relationships. The key goals are to define relevant classes and their attributes, operations, relationships, and behaviors through iterative refinement. Various analysis methods take different approaches, but generally involve use case modeling, class modeling, and behavior modeling.
The document discusses use case diagrams in UML modeling. It defines key components of use case diagrams including use cases, actors, the system boundary, and relationships like include, extend, and generalization. It provides examples of how to construct a use case diagram based on system functions and user goals. Specific use case diagram examples shown include an online ordering system and a vending machine.
Function-oriented design views a system as modules with clearly defined behaviors that interact to meet requirements. It discusses various design methodologies including structured design methodology which involves identifying inputs/outputs and transformations, and factoring modules into submodules. Design quality can be evaluated using metrics related to cohesion, coupling, complexity, and information flow.
Design and Implementation in Software EngineeringKourosh Sajjadi
These slides were presented to the software engineering class held in IAUN. The main context is provided from the "Software Engineering" book authored by Sommerville.
Most of the icons used in the slides are provided in the flaticon.com website.
Thanks to our professor Habib Seifzadeh.
A cooperation with Mohammad Mostajeran.
Use case diagrams describe interactions between actors and a system to accomplish goals. A use case diagram typically includes:
1) Actors that interact with the system from outside, such as users or other systems. Common actor types are primary actors whose goals are fulfilled by the system and supporting actors that provide services.
2) Use cases that represent functions or tasks performed by the system. They are connected to relevant actors and may have relationships like include and extend.
3) Relationships between use cases like include, which shows a use case incorporating another, and extend, where a use case optionally extends another.
Use case diagrams provide an overview of a system's functions and how outside actors interact with them at a
The document discusses the software development life cycle (SDLC) which includes 8 phases: system conception, requirement gathering, system design, class design, implementation, testing, deployment, and maintenance. It states that requirement gathering focuses on what must be done without how, and involves domain and application analysis. Domain analysis emphasizes real-world objects to understand the problem domain. The implementation phase is the longest as it involves coding the requirements.
The document provides an overview of basic software design concepts including the design process, quality factors, techniques, methodologies, approaches, models, modularization, data design, guidelines, verification, and key issues. It discusses that software design is an iterative process of translating requirements into a system blueprint. The design process involves informal to more formal designs. Quality factors, architectures, technologies, styles, and decomposition are considered. Top-down and bottom-up approaches are described. Modularization, data design, and guidelines are covered. Verification ensures the design is valid before implementation. Key issues are areas most prone to mistakes.
Object modeling involves identifying important objects (classes) within a system and defining their attributes, operations, and relationships. During object modeling, classes are identified based on system requirements and domain concepts. Key activities include class identification, defining class attributes and methods, and determining associations between classes. Object modeling results in a visual representation of classes and their relationships in class and other diagrams.
This document discusses software quality and metrics. It defines software quality as conformance to requirements, standards, and implicit expectations. It outlines ISO 9126 quality factors like functionality, reliability, usability, and maintainability. It describes five views of quality: transcendental, user, manufacturing, product, and value-based. It also discusses types of metrics like product, process, and project metrics. Product metrics measure characteristics like size, complexity, and quality level. The document provides guidelines for developing, collecting, analyzing, and interpreting software metrics.
The document provides an overview of architectural design in software engineering. It defines software architecture as the structure of components, relationships between them, and properties. The key steps in architectural design are creating data design, representing structure, analyzing styles, and elaborating chosen style. It emphasizes software components and their focus. Examples of architectural styles discussed include data flow, call-and-return, data-centered, and virtual machine.
Unit 7 performing user interface designPreeti Mishra
The document discusses user interface design principles and models. It provides three key principles for user interface design:
1. Place users in control of the interface and allow for flexible, interruptible, and customizable interaction.
2. Reduce users' memory load by minimizing what they need to remember, establishing defaults, and progressively disclosing information.
3. Make the interface consistent across screens, applications, and interaction models to maintain user expectations.
It also describes four models involved in interface design: the user profile model, design model, implementation model, and user's mental model. The role of designers is to reconcile differences across these models.
software development, process model, requirement engineering, srs, structured...Ashok Mohanty
This document provides an overview of software engineering. It begins by discussing the emergence of software engineering as a discipline due to the "software crisis" of the 1970s. It then covers various software engineering processes and lifecycle models, including sequential models like waterfall and iterative models like prototyping and spiral. Requirements engineering methods like elicitation, analysis and specification are also summarized. Finally, it discusses the function-oriented and object-oriented approaches to software development.
Architecture design in software engineeringPreeti Mishra
The document discusses software architectural design. It defines architecture as the structure of a system's components, their relationships, and properties. An architectural design model is transferable across different systems. The architecture enables analysis of design requirements and consideration of alternatives early in development. It represents the system in an intellectually graspable way. Common architectural styles structure systems and their components in different ways, such as data-centered, data flow, and call-and-return styles.
The document discusses the differences between analysis modeling and design engineering/modeling. Analysis involves understanding a problem, while design focuses on creating a solution. Models can be used to better understand problems in analysis or solutions in design. The key aspects of design engineering are then outlined, including translating requirements into a software blueprint, iterating on the design, and ensuring quality through guidelines such as modularity, information hiding, and functional independence. Common design concepts like abstraction, architecture, patterns, and classes are also explained.
This document discusses software design principles and concepts. It covers key aspects of software design such as data design, architectural design, interface design, component design, abstraction, refinement, modularity, architecture, control hierarchy, structural partitioning, data structures, software procedures, and information hiding. The document emphasizes that software design is an iterative process that translates requirements into a blueprint for constructing software. Good design principles include traceability, reuse, and accommodating change. Modular design aims for functional independence, cohesion and low coupling between modules.
The design model transforms requirements from the analysis model into a blueprint for constructing the software. It includes four main elements: the data/class design, architectural design, interface design, and component-level design. These elements are developed iteratively through increasing levels of abstraction, starting with high-level elements that are traced to requirements and refining into lower-level representations. The design model aims to implement requirements while considering quality guidelines around modularity, patterns, and other design concepts.
The document discusses various aspects of design modeling for software engineering projects. It describes how the design model builds upon the analysis model by refining and adding more implementation details to elements like data design, architectural design, interface design, and component design. It also covers important design concepts like abstraction, architecture, patterns, modularity, information hiding, and functional independence. Quality guidelines for software design are provided along with principles of object-oriented design.
The document discusses key concepts in design modeling for software engineering projects, including:
- Data/class design transforms analysis models into design class structures and data structures.
- Architectural design defines relationships between major software elements and how they interact.
- Interface, component, and other designs further refine elements from analysis into implementation-specific details.
- Design principles include traceability to analysis, avoiding reinventing solutions, and structuring for change and graceful degradation.
The document discusses key design concepts in software engineering including abstraction, architecture, patterns, separation of concerns, modularity, information hiding, refinement, functional independence, aspects, refactoring, object-oriented design concepts, and design classes. It provides details on each concept, their importance in software design, and how they lead to the development of high-quality software.
The document discusses key concepts in software design including abstraction, modularity, information hiding, functional independence, and refactoring. It also covers design patterns, architectural patterns, data abstraction, procedural abstraction, architecture, and principles of good modular design.
The document discusses key concepts in software design, including:
- Design involves modeling the system architecture, interfaces, and components before implementation. This allows assessment and improvement of quality.
- Important design concepts span abstraction, architecture, patterns, separation of concerns, modularity, information hiding, and functional independence. Architecture defines overall structure and interactions. Patterns help solve common problems.
- Separation of concerns and related concepts like modularity and information hiding help decompose problems into independently designed and optimized pieces to improve manageability. Functional independence means each module has a single, well-defined purpose with minimal interaction.
The document discusses key concepts in software design, including:
- Mitch Kapor's "software design manifesto" emphasized good design exhibiting firmness, commodity, and delight.
- Design encompasses principles, concepts, and practices that lead to high quality systems, including data/class design, architectural design, interface design, and component-level design.
- Quality guidelines for design include modularity, distinct representations of elements, appropriate data structures, independent components, and reduced complexity interfaces.
This document discusses key concepts and principles of software design. It explains that software design transforms analysis models into a design model through activities like architectural design, interface design, data design, and component-level design. Some key design concepts discussed include abstraction, refinement, modularity, architecture, procedures, and information hiding. The document also covers principles of effective modular design such as high cohesion and low coupling between modules. Different types of cohesion and coupling are defined. Overall, the document provides an overview of the software design process and some fundamental concepts involved.
Software design is an iterative process that translates requirements into a blueprint for constructing software. It involves understanding the problem from different perspectives, identifying solutions, and describing solution abstractions using notations. The design must satisfy users and developers by being correct, complete, understandable, and maintainable. During the design process, specifications are transformed into design models describing data structures, architecture, interfaces, and components, which are reviewed before development.
The document provides information on a course titled "Software Engineering" taught by Dr. P. Visu at Velammal Engineering College. It includes the course objectives, outcomes, syllabus, and learning resources. The objectives are to understand software project phases, requirements engineering, object-oriented concepts, enterprise integration, and testing techniques. The outcomes cover comparing process models, requirements engineering, object-oriented fundamentals, software design, and testing techniques. The syllabus covers topics like software processes, requirements analysis, object-oriented concepts, software design, testing, and project management over 5 units. Recommended textbooks and online references are also provided.
The document discusses key concepts in design engineering for software. It covers principles like abstraction, refinement, modularity, architecture, and information hiding that are important for developing high quality software. It emphasizes that software design is an iterative process of translating requirements into lower levels of abstraction until implementation. The goals of design are to implement all requirements, provide an understandable guide for developers and testers, and give a complete picture of the software from an implementation perspective. Guidelines are provided for characteristics of good design like modularity, distinct representations, and deriving the design from requirements analysis.
The document provides information on a course titled "Software Engineering" taught by Dr. P. Visu at Velammal Engineering College. It includes the course objectives, outcomes, syllabus, and learning resources. The objectives are to understand software project phases, requirements engineering, object-oriented concepts, enterprise integration, and testing techniques. The outcomes cover comparing process models, formulating requirements engineering concepts, understanding object-oriented fundamentals, applying software design procedures, and finding errors with testing techniques. The syllabus covers topics like software processes, requirements analysis, object-oriented concepts, software design, and testing and management over 5 units. Recommended textbooks and online references are also provided.
The document discusses several key concepts in software design:
- Abstraction, architecture, patterns, modularity, information hiding, functional independence, stepwise refinement, and refactoring are design concepts that help structure a program.
- The design process transforms an analysis model into four design models: data/class design, architectural design, user interface design, and component-level design.
- The design model is more detailed than the analysis model and addresses progression, abstraction, and the relationship between elements.
Software engineering is a detailed study of engineering to the design, development and maintenance of software. Software engineering was introduced to address the issues of low-quality software projects.
The document discusses key aspects of the software design process including that design is iterative and represented at a high level of abstraction, guidelines for quality design include modularity, information hiding, and functional independence, and architectural design defines system context and archetypes that compose the system.
This ppt covers the following topics :-
Introduction
Design quality
Design concepts
The design model
Thus it covers design engineering in software engineering
The document discusses key concepts in software design including the design process, design models, translating requirements to design, and quality attributes. It describes how design brings together requirements, business needs, and technical considerations to provide a blueprint for software construction. The design model includes data structures, architecture, interfaces, and components. Translating requirements involves creating class, architectural, interface, and component designs. Quality is assessed based on functionality, usability, reliability, performance, and other attributes.
Object diagrams represent a snapshot of a system at a particular moment, showing the concrete instances of classes and their relationships. They capture the static view of a system to show object behaviors and relationships from a practical perspective. Unlike class diagrams which show abstract representations, object diagrams depict real-world objects and their unlimited possible instances. They are used for forward and reverse engineering, modeling object relationships and interactions, and understanding system behavior.
Sequence diagrams show the interactions between objects over time by depicting object lifelines and messages exchanged. They emphasize the time ordering of messages. To create a sequence diagram, identify participating objects and messages, lay out object lifelines across the top, and draw messages between lifelines from top to bottom based on timing. Activation boxes on lifelines indicate when objects are active. Sequence diagrams help document and understand the logical flow of a system.
State chart diagrams define the different states an object can be in during its lifetime, and how it transitions between states in response to events. They are useful for modeling reactive systems by describing the flow of control from one state to another. The key elements are initial and final states, states represented by rectangles, and transitions between states indicated by arrows. State chart diagrams are used to model the dynamic behavior and lifetime of objects in a system and identify the events that trigger state changes.
Unit 8 discusses software testing concepts including definitions of testing, who performs testing, test characteristics, levels of testing, and testing approaches. Unit testing focuses on individual program units while integration testing combines units. System testing evaluates a complete integrated system. Testing strategies integrate testing into a planned series of steps from requirements to deployment. Verification ensures correct development while validation confirms the product meets user needs.
This document discusses requirements analysis and design. It covers the types and characteristics of requirements, as well as the tasks involved in requirements engineering including inception, elicitation, elaboration, negotiation, specification, validation, and management. It also discusses problems that commonly occur in requirements practices and solutions through proper requirements engineering. Additionally, it outlines goals and elements of analysis modeling, including flow-oriented, scenario-based, class-based, and behavioral modeling. Finally, it discusses the purpose and tasks of design engineering in translating requirements models into design models.
Design process interaction design basicsPreeti Mishra
This document provides an introduction to interaction design basics and terms. It discusses that interaction design involves creating technology-based interventions to achieve goals within constraints. The design process has several stages and is iterative. Interaction design starts with understanding users through methods like talking to and observing them. Scenarios are rich stories used throughout design to illustrate user interactions. Basic terms in interaction design include goals, constraints, trade-offs, and the design process. Usability and user-centered design are also discussed.
The document provides an overview of design process and factors that affect user experience in interface design. It discusses various principles and heuristics to support usability, including learnability, flexibility, and robustness. The document outlines principles that affect these factors, such as predictability, consistency and dialog initiative. It also discusses guidelines for improving usability through user testing and iterative design. The document emphasizes the importance of usability and provides several heuristics and guidelines to measure and improve usability in interface design.
Design process evaluating interactive_designsPreeti Mishra
The document discusses various methods for evaluating interactive systems, including expert analysis methods like heuristic evaluation and cognitive walkthrough, as well as user-based evaluation techniques like observational methods, query techniques, and physiological monitoring. It provides details on the process for each method and considerations for when each may be most appropriate. Evaluation aims to determine a system's usability, identify design issues, compare alternatives, and observe user effects. The criteria discussed include expert analysis, user-based, and model-based approaches.
Foundations understanding users and interactionsPreeti Mishra
This document discusses qualitative user research methods. It explains that qualitative research helps understand user behavior, which is too complex to understand solely through quantitative data. Qualitative research methods include interviews, observation, and persona creation. Personas are fictional user archetypes created from interview data to represent different types of users. They are useful for product design by providing empathy for users and guiding decisions. The document provides details on creating personas and using scenarios to represent how personas would interact with a product.
This document provides an introduction to human-computer interaction (HCI). It defines HCI as a discipline concerned with studying, designing, building, and implementing interactive computing systems for human use, with a focus on usability. The document outlines various perspectives in HCI including sociology, anthropology, ergonomics, psychology, and linguistics. It also defines HCI and lists 8 guidelines for creating good HCI, such as consistency, informative feedback, and reducing memory load. The importance of good interfaces is discussed, noting they can make or break a product's acceptance. Finally, some principles and theories of user-centered design are introduced.
The document provides an overview of system development methodologies, with a focus on structured analysis and design versus object-oriented analysis and design. It discusses the analysis, design, and implementation phases of an object-oriented systems development life cycle. In the analysis phase, it describes how use case diagrams and class diagrams are used to model object-oriented analysis using the Unified Modeling Language. It also provides guidance on identifying domain classes from problem statements by looking for noun phrases and applying subject matter expertise.
The document discusses modeling different aspects of software systems using UML diagrams. It covers modeling events using state machines, the four types of events that can be modeled in UML (signals, calls, time, and state change), modeling logical database schemas using class diagrams, modeling source code using artifact diagrams, modeling executable releases using artifact diagrams to show deployment artifacts and relationships, and modeling physical databases by defining tables for classes while considering inheritance relationships.
This document provides an introduction to object-oriented concepts and methodologies. It defines key OO terms like abstraction, encapsulation, polymorphism, and more. It also discusses object-oriented modeling techniques and popular object-oriented methodologies like Booch, RDD, OMT, and OOSE. The document aims to equip readers with an understanding of fundamental OO principles and how they are applied in analysis, design, and implementation of object-oriented systems.
This document provides an overview of functional modeling and data flow diagrams. It discusses that functional modeling gives the process perspective of object-oriented analysis and defines the functions and data flows within a system. It then describes different types of functional models including functional flow block diagrams and data flow diagrams. It provides details on how to construct functional flow block diagrams including the use of function blocks, numbering, references, flow connections, direction and gates. It also notes some potential problems with functional modeling.
This document provides an overview of software processes and the Capability Maturity Model Integration (CMMI). It defines what a software process is, characteristics of processes, and that different project types require different processes. It then describes the key elements of the CMMI, including its five maturity levels from Initial to Optimizing. Each level is defined in one sentence or less. It also briefly outlines some of the key process areas assessed at levels 2 through 5.
Unit 1 importance ofsoftengg_b.tech iii yearPreeti Mishra
Here are some key points from Unit 1:
- Software is computer programs, data structures, and documentation. Software engineering is the systematic development and maintenance of software.
- A software process provides a framework for development activities like communication, planning, modeling, construction and deployment. It establishes quality practices.
- Legacy software supports core functions but is outdated, poorly designed and documented. It is costly to replace but also to maintain.
- Common software myths include thinking requirements can change freely, documentation is unnecessary, or that quality is only important after coding. These undermine good practices.
- A process framework provides structure while methods and tools support specific technical tasks. Processes must balance control and flexibility for different projects.
Unit 1 introduction tosoftengg_mba tech ii yearPreeti Mishra
This document provides an introduction to software engineering. It defines software and discusses different categories of software products. It explains that software engineering is concerned with developing software using systematic and disciplined approaches. The document outlines important attributes of good software such as maintainability, dependability, efficiency and acceptability. It also discusses challenges with legacy software systems and reasons for evolving legacy systems. Finally, it covers key tasks for software project planning such as establishing scope, feasibility analysis, risk analysis, resource estimation, and developing a project schedule.
This document outlines a lecture on software engineering. It begins by defining software and engineering. Software engineering is then defined as the application of engineering principles to the design, development, and maintenance of software. The limitations of non-engineered software, such as cost and time overruns and poor quality, are discussed using examples from the space shuttle and commercial software. There was a need for software engineering to address these issues and ensure software is built systematically, rigorously, measurably, on time, on budget, and within specifications. The lecture will cover theoretical concepts, exercises, case studies, and modeling techniques using UML in theory, tutorial, and lab classes. Class rules around timing and academic integrity are also outlined.
Online train ticket booking system project.pdfKamal Acharya
Rail transport is one of the important modes of transport in India. Now a days we
see that there are railways that are present for the long as well as short distance
travelling which makes the life of the people easier. When compared to other
means of transport, a railway is the cheapest means of transport. The maintenance
of the railway database also plays a major role in the smooth running of this
system. The Online Train Ticket Management System will help in reserving the
tickets of the railways to travel from a particular source to the destination.
Data Communication and Computer Networks Management System Project Report.pdfKamal Acharya
Networking is a telecommunications network that allows computers to exchange data. In
computer networks, networked computing devices pass data to each other along data
connections. Data is transferred in the form of packets. The connections between nodes are
established using either cable media or wireless media.
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Particle Swarm Optimization–Long Short-Term Memory based Channel Estimation w...IJCNCJournal
Paper Title
Particle Swarm Optimization–Long Short-Term Memory based Channel Estimation with Hybrid Beam Forming Power Transfer in WSN-IoT Applications
Authors
Reginald Jude Sixtus J and Tamilarasi Muthu, Puducherry Technological University, India
Abstract
Non-Orthogonal Multiple Access (NOMA) helps to overcome various difficulties in future technology wireless communications. NOMA, when utilized with millimeter wave multiple-input multiple-output (MIMO) systems, channel estimation becomes extremely difficult. For reaping the benefits of the NOMA and mm-Wave combination, effective channel estimation is required. In this paper, we propose an enhanced particle swarm optimization based long short-term memory estimator network (PSOLSTMEstNet), which is a neural network model that can be employed to forecast the bandwidth required in the mm-Wave MIMO network. The prime advantage of the LSTM is that it has the capability of dynamically adapting to the functioning pattern of fluctuating channel state. The LSTM stage with adaptive coding and modulation enhances the BER.PSO algorithm is employed to optimize input weights of LSTM network. The modified algorithm splits the power by channel condition of every single user. Participants will be first sorted into distinct groups depending upon respective channel conditions, using a hybrid beamforming approach. The network characteristics are fine-estimated using PSO-LSTMEstNet after a rough approximation of channels parameters derived from the received data.
Keywords
Signal to Noise Ratio (SNR), Bit Error Rate (BER), mm-Wave, MIMO, NOMA, deep learning, optimization.
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2. Introduction
Analysis Model
use-cases - text
use-case diagrams
activity diagrams
swim lane diagrams
data flow diagrams
control-flow diagrams
processing narratives
f low- or ient ed
element s
behavior al
element s
class- based
element s
scenar io- based
element s
class diagrams
analysis packages
CRC models
collaboration diagrams
state diagrams
sequence diagrams
Da t a / Cla ss De sign
Arc hit e c t ura l De sign
Int e rfa c e De sign
Com pone nt -
Le v e l De sign
Design Model
3. Programmer’s Approach to Software Engineering
Skip requirements engineering and design phases;
start writing code
Why this programmer’s approach?
Design is a waste of time
We need to show something to the customer real quick
We are judged by the amount of LOC/month
5. Software design as a “wicked” problem
• There is no definite formulation
• There is no stopping rule
• Solutions are not simply true or false
• Every wicked problem is a symptom of another problem
6. Purpose of Design
• Design is where customer requirements, business needs, and technical considerations all come together in the
formulation of a product or system
• The design model provides detail about the software data structures, architecture, interfaces, and components
• The design model can be assessed for quality and be improved before code is generated and tests are conducted
– Does the design contain errors, inconsistencies, or omissions?
– Are there better design alternatives?
– Can the design be implemented within the constraints, schedule, and cost that have been established?
• A designer must practice diversification and convergence
– The designer selects from design components, component solutions, and knowledge available through catalogs, textbooks,
and experience
– The designer then chooses the elements from this collection that meet the requirements defined by requirements engineering
and analysis modeling
– Convergence occurs as alternatives are considered and rejected until one particular configuration of components is chosen
• Software design is an iterative process through which requirements are translated into a blueprint for constructing
the software
– Design begins at a high level of abstraction that can be directly traced back to the data, functional, and behavioral
requirements
– As design iteration occurs, subsequent refinement leads to design representations at much lower levels of abstraction
7. Design and Quality
• the design must implement all of the explicit requirements contained in the analysis
model, and it must accommodate all of the implicit requirements desired by the
customer.
• the design must be a readable, understandable guide for those who generate code
and for those who test and subsequently support the software.
• the design should provide a complete picture of the software, addressing the data,
functional, and behavioral domains from an implementation perspective.
8. Quality Guidelines
• A design should exhibit an architecture that :
– (1) has been created using recognizable architectural styles or patterns,
– (2) is composed of components that exhibit good design characteristics and
– (3) can be implemented in an evolutionary fashion
For smaller systems, design can sometimes be developed linearly.
• A design should be modular; that is, the software should be logically partitioned into elements or
subsystems
• A design should contain distinct representations of data, architecture, interfaces, and components.
• A design should lead to data structures that are appropriate for the classes to be implemented and
are drawn from recognizable data patterns.
• A design should lead to components that exhibit independent functional characteristics.
• A design should lead to interfaces that reduce the complexity of connections between components
and with the external environment.
• A design should be derived using a repeatable method that is driven by information obtained during
software requirements analysis.
• A design should be represented using a notation that effectively communicates its meaning.
10. Design Principles
• The design process should not suffer from ‘tunnel vision.’
• The design should be traceable to the analysis model.
• The design should not reinvent the wheel.
• The design should “minimize the intellectual distance” between the software and the problem as it
exists in the real world.
• The design should exhibit uniformity and integration.
• The design should be structured to accommodate change.
• The design should be structured to degrade gently, even when aberrant data, events, or operating
conditions are encountered.
• Design is not coding, coding is not design.
• The design should be assessed for quality as it is being created, not after the fact.
• The design should be reviewed to minimize conceptual (semantic) errors.
11. Fundamental Concepts
• Abstraction—data, procedure, control
• Architecture—the overall structure of the software
• Patterns—”conveys the essence” of a proven design solution
• Separation of concerns—any complex problem can be more easily handled if it is subdivided into
pieces
• Modularity—compartmentalization of data and function
• Hiding—controlled interfaces
• Functional independence—single-minded function and low coupling
• Refinement—elaboration of detail for all abstractions
• Aspects—a mechanism for understanding how global requirements affect design
• Refactoring—a reorganization technique that simplifies the design
• OO design concepts—(Already done see slide Object Oriented Concepts)
• Design Classes—provide design detail that will enable analysis classes to be implemented( already
Done)
12. Design Concepts
• Abstraction
– Procedural abstraction – a sequence of instructions that have a specific and limited function
– Data abstraction – a named collection of data that describes a data object
• Architecture
– The overall structure of the software and the ways in which the structure provides conceptual integrity for a system
– Consists of components, connectors, and the relationship between them
• Patterns
– A design structure that solves a particular design problem within a specific context
– It provides a description that enables a designer to determine whether the pattern is applicable, whether the pattern can be
reused, and whether the pattern can serve as a guide for developing similar patterns
• Modularity
– Separately named and addressable components (i.e., modules) that are integrated to satisfy requirements (divide and
conquer principle)
– Makes software intellectually manageable so as to grasp the control paths, span of reference, number of variables, and
overall complexity
• Information hiding
– The designing of modules so that the algorithms and local data contained within them are inaccessible to other modules
– This enforces access constraints to both procedural (i.e., implementation) detail and local data structures
13. Design Concepts
• Functional independence
– Modules that have a "single-minded" function and an aversion to excessive interaction with other modules
– High cohesion – a module performs only a single task
– Low coupling – a module has the lowest amount of connection needed with other modules
• Stepwise refinement
– Development of a program by successively refining levels of procedure detail
– Complements abstraction, which enables a designer to specify procedure and data and yet suppress low-level
details
• Refactoring
– A reorganization technique that simplifies the design (or internal code structure) of a component without
changing its function or external behavior
– Removes redundancy, unused design elements, inefficient or unnecessary algorithms, poorly constructed or
inappropriate data structures, or any other design failures
• Design classes
– Refines the analysis classes by providing design detail that will enable the classes to be implemented
– Creates a new set of design classes that implement a software infrastructure to support the business solution
14. Data Abstraction
door
implemented as a data structure
manufacturer
model number
type
swing direction
inserts
lights
type
number
weight
opening mechanism
16. Architecture
“The overall structure of the software and the ways in
which that structure provides conceptual integrity for a
system.” [SHA95a]
Structural properties. This aspect of the architectural design representation defines the components of
a system (e.g., modules, objects, filters) and the manner in which those components are packaged and
interact with one another.
Extra-functional properties. The architectural design description should address how the design
architecture achieves requirements for performance, capacity, reliability, security, adaptability, and other
system characteristics.
Families of related systems. The architectural design should draw upon repeatable patterns that are
commonly encountered in the design of families of similar systems. In essence, the design should have
the ability to reuse architectural building blocks.
17. Patterns
Design Pattern Template
Pattern name—describes the essence of the pattern in a short but expressive name
Intent—describes the pattern and what it does
Also-known-as—lists any synonyms for the pattern
Motivation—provides an example of the problem
Applicability—notes specific design situations in which the pattern is applicable
Structure—describes the classes that are required to implement the pattern
Participants—describes the responsibilities of the classes that are required to implement the pattern
Collaborations—describes how the participants collaborate to carry out their responsibilities
Consequences—describes the “design forces” that affect the pattern and the potential trade-offs that must
be considered when the pattern is implemented
Related patterns—cross-references related design patterns
18. Separation of Concerns
• Any complex problem can be more easily handled if it is subdivided into
pieces that can each be solved and/or optimized independently
• A concern is a feature or behavior that is specified as part of the
requirements model for the software
• By separating concerns into smaller, and therefore more manageable
pieces, a problem takes less effort and time to solve.
21. Why Information Hiding?
• reduces the likelihood of “side effects”
• limits the global impact of local design decisions
• emphasizes communication through controlled interfaces
• discourages the use of global data
• leads to encapsulation—an attribute of high quality design
• results in higher quality software
22. Stepwise Refinement
open
walk to door;
reach for knob;
open door;
walk through;
close door.
repeat until door opens
turn knob clockwise;
if knob doesn't turn, then
take key out;
find correct key;
insert in lock;
endif
pull/push door
move out of way;
end repeat
24. Functional Independence
• Functional independence is achieved by developing modules with "single-minded" function
and an "aversion" to excessive interaction with other modules.
• Cohesion is an indication of the relative functional strength of a module.
– A cohesive module performs a single task, requiring little interaction with other components in other
parts of a program. Stated simply, a cohesive module should (ideally) do just one thing.
• Coupling is an indication of the relative interdependence among modules.
– Coupling depends on the interface complexity between modules, the point at which entry or
reference is made to a module, and what data pass across the interface.
– See more in the slides : Cohesion and Coupling
25. Aspects
• Consider two requirements, A and B. Requirement A
crosscuts requirement B “if a software decomposition
[refinement] has been chosen in which B cannot be satisfied
without taking A into account. [Ros04]
• An aspect is a representation of a cross-cutting concern.
26. Refactoring
• Fowler [FOW99] defines refactoring in the following manner:
– "Refactoring is the process of changing a software system in such a way that it does not alter the external
behavior of the code [design] yet improves its internal structure.”
• When software is refactored, the existing design is examined for
– redundancy
– unused design elements
– inefficient or unnecessary algorithms
– poorly constructed or inappropriate data structures
– or any other design failure that can be corrected to yield a better design.
29. 29
The Design Model
archit ect ure
element s
int erface
element s
component -level
element s
deployment -level
element s
low
high
class diagrams
analysis packages
CRCmodels
collaborat ion diagrams
use-cases - t ext
use-case diagrams
act ivit y diagrams
swim lane diagrams
collaborat ion diagrams dat a f low diagrams
cont rol-f low diagrams
processing narrat ives
dat a f low diagrams
cont rol-f low diagrams
processing narrat ives
st at e diagrams
sequence diagrams
st at e diagrams
sequence diagrams
design class realizat ions
subsyst ems
collaborat ion diagrams
design class realizat ions
subsyst ems
collaborat ion diagrams
ref inement s t o:
deployment diagrams
class diagrams
analysis packages
CRC models
collaborat ion diagrams
component diagrams
design classes
act ivit y diagrams
sequence diagrams
ref inement s t o:
component diagrams
design classes
act ivit y diagrams
sequence diagrams
design class realizat ions
subsyst ems
collaborat ion diagrams
component diagrams
design classes
act ivit y diagrams
sequence diagrams
a na ly sis mode l
de sign mode l
Requirement s:
const raint s
int eroperabilit y
t arget s and
conf igurat ion
t echnical int erf ace
design
Navigat ion design
GUI design
31. Types of Design Classes
• User interface classes – define all abstractions necessary for human-computer interaction
(usually via metaphors of real-world objects)
• Business domain classes – refined from analysis classes; identify attributes and services
(methods) that are required to implement some element of the business domain
• Process classes – implement business abstractions required to fully manage the business domain
classes
• Persistent classes – represent data stores (e.g., a database) that will persist beyond the execution
of the software
• System classes – implement software management and control functions that enable the system
to operate and communicate within its computing environment and the outside world
32. Characteristics of a Well-Formed Design Class
• Complete and sufficient
– Contains the complete encapsulation of all attributes and methods that exist for the class
– Contains only those methods that are sufficient to achieve the intent of the class
• Primitiveness
– Each method of a class focuses on accomplishing one service for the class
• High cohesion
– The class has a small, focused set of responsibilities and single-mindedly applies attributes and methods to
implement those responsibilities
• Low coupling
– Collaboration of the class with other classes is kept to an acceptable minimum
– Each class should have limited knowledge of other classes in other subsystems
33. Design Model Elements
• Data elements
– Data model --> data structures
– Data model --> database architecture
• Architectural elements
– Application domain
– Analysis classes, their relationships, collaborations and behaviors are transformed into design realizations
– Patterns and “styles” (Chapters 9 and 12)
• Interface elements( Interface Diagram/ Class diagram)
– the user interface (UI)
– external interfaces to other systems, devices, networks or other producers or consumers of information
– internal interfaces between various design components.
• Component elements( Component diagram See slide on BBLMS Discussions)
• Deployment elements( Deployment diagram See slide on BBLMS Discussions)
34. Architectural Elements
• The architectural model [Sha96] is derived from three sources:
– information about the application domain for the software to be built;
– specific requirements model elements such as data flow diagrams or analysis
classes, their relationships and collaborations for the problem at hand, and
– the availability of architectural patterns
35. Pattern-based Software Design
• Mature engineering disciplines make use of thousands of design patterns for such things as buildings, highways,
electrical circuits, factories, weapon systems, vehicles, and computers
• Design patterns also serve a purpose in software engineering
• Architectural patterns
– Define the overall structure of software
– Indicate the relationships among subsystems and software components
– Define the rules for specifying relationships among software elements
• Design patterns
– Address a specific element of the design such as an aggregation of components or solve some design problem,
relationships among components, or the mechanisms for effecting inter-component communication
– Consist of creational, structural, and behavioral patterns
• Coding patterns
– Describe language-specific patterns that implement an algorithmic or data structure element of a component, a specific
interface protocol, or a mechanism for communication among components
36. 36
From Analysis Model to
Design Model
Data/Class Design
(Class-based model, Behavioral model)
Architectural Design
(Class-based model, Flow-oriented model)
Interface Design
(Scenario-based model, Flow-oriented model
Behavioral model)
Component-level Design
(Class-based model, Flow-oriented model
Behavioral model)
37. FAQ on Design Engineering
• What : Design, design engineering, steps for design engineering,
design and quality, quality principle, design principle, pattern,
framework, architecture, component, deployment
• Differentiate: refactoring-refinement, architecture-pattern,
analysis-design class,
• Describe: analysis model elements, steps for design
engineering, design model elements, various design classes