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Many-Electron Atoms and Electron Configurations | Ch 6 - 63E

Chemistry: The Central Science | 12th Edition | ISBN: 9780321696724 | Authors: Theodore E. Brown; H. Eugene LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward ISBN: 9780321696724 27

Solution for problem 63E Chapter 6

Chemistry: The Central Science | 12th Edition

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Chemistry: The Central Science | 12th Edition | ISBN: 9780321696724 | Authors: Theodore E. Brown; H. Eugene LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward

Chemistry: The Central Science | 12th Edition

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Problem 63E

Problem 63E

Many-Electron Atoms and Electron Configurations (Sections)

(a) What experimental evidence is there for the electron having a “spin”? (b) Draw an energy-level diagram that shows the relative energetic positions of a 1s orbital and a 2s orbital. Put two electrons in the 1s orbital. (c) Draw an arrow showing the excitation of an electron from the 1s to the 2s orbital.

Step-by-Step Solution:
Step 1 of 3

Systems Development Life Cycle 1. Planning Phase: Why should we build this system What value does it provide How long will it take to build 2 phases in planning are: 1. 1.) Project Initiation: The system’s business value to the organization is identified. System Request: A request presents a brief summary of a business need, and it explains how a system that supports the need will create business value. Feasibility Analysis: Can we build it Will it provide business value If we build it, will it be used 2.) Project Management: A project plan, which describes how the project team will go about developing the system. A project manager creates a work plan, staffs the project, and puts techniques in place to help the project team control and direct the project through the entire SDLC. (Staffing Budgeting, Contract, management, Maintenance, operations and support, cross or inter project issues) 2. Analysis Phase: Who will use it specifically What should the system do for us Where & when will it be used 3 phases in analysis are: 1. 1.) Analysis Strategy: An analysis of the current system (as-is system) and its problems and then ways to design a new system (to-be system) Requirements Gathering: Through interviews, questionnaires, and input from project sponsor and many other people, this leads to the development of a concept for a new system. Analysis Models: The set of models typically includes models that represent the data and processes necessary to support the underlying business process. 2.) System Proposal: Presented to the project sponsor and other key decision makers who decide whether the project continue to move forward. 3. Design Phase: How the system will operate in terms of the hardware, software and network infrastructure; the user interface; forms and reports; and the specific programs, databases, and files that will be needed. 4 phases in the design phase are: 1. 1.) Design Strategy: It clarifies whether the system will be developed by the company’s own programmers, whether the system will be outsourced to another firm, or whether the company will buy an existing software package. 2.) Design Architecture: Describes the hardware, software, and network infrastructure to be used. Interface Design: Specifies how the users will more through the system (navigation methods such as menus and on-screen buttons) and the forms and reports that the system will use. 3.) Database and file specifications: This defines exactly what data will be stored and where they will be stored. 4.) Program specifications/designs: Defines the programs that need to be written and exactly what each program will do. 4. Implementation: 4 phases in the implementation phase are: 1. 1.) Construction: The system is built and tested to ensure it performs as designed. Testing is one of the most critical steps in implementation. 2.) Installation: The process by which the old system is turned off and the new one is turned on. 3.) Training plan: To each users how to use the new system and help manage the changes caused by the new system. 4.) Support plan: Post implementation review as well as systematic way for identifying major and minor changes needed for the system. Methodologies 1. Structured Development: A formal step by step approach to the SDLC that moves logically from one phase to the next. (Waterfall, Parallel) 2. Rapid application development: It attempts to address both weaknesses of structured design methodologies by adjusting the SDLC phases to get some part of the system developed quickly and into the hands of the users. In this way, the users can better understand the system and suggest revisions that bring the system closer to what is needed. Phased, prototyping throwaway prototyping) 3. Agile Development: Focus the developers on the working conditions of the developers, the working software, the customers, and addressing changing requirements instead of focusing on detailed systems development processes, tools all inclusive documentation, legal contracts, and detailed plans. (Extreme programming, scrum) The unified process: A specific methodology that maps out when and how to use the various UML techniques for object oriented analysis and design. A two dimensional process consisting of phases and workflows. 1. Unified phases process: The time periods in development. a. Inception phase: Performs the feasibility analysis. Workflows vary but focus is on business modeling and requirements gathering. Elaboration phase: Heavy focus on analysis and design. Other workflows may be included. Construction phase: Focuses on programming. (implementation) Transition phase: Focus on testing and deployment 2. Workflows are the tasks that occur in each phase. Activities in both phases & workflows will overlap. a. Engineering Workflows i. 1.) Business Modeling Workflow: Uncovers problems and identifies potential projects within a user organization. Understanding the scope of the projects that can improve the efficiency and effectiveness of a user organization. Ensure that both the developer and user organizations understand where and how the to-be developed information system fits into the business processes of the organization. Inception phase. 2.) Requirements Workflow: Eliciting both functional and nonfunctional requirements. Different ways to capture requirements such as interviewing, observation techniques, join application development, document analysis, and questionnaires. Very helpful for developing the vision document and the use cases used throughout the development process. Inception and elaboration phase. Analysis Workflow: Addresses the creation of analysis model of the problem domain; The analyst creates structural and behavior diagrams that depict a description of the problem domain classes and their interactions; The primary purpose of the analysis workflow is to ensure that both the developer and user organizations understand the underlying problem and its domain without overanalyzing; Understanding the problem domain; Elaboration phase. 3.) Design Workflow: Transitions the analysis model into a form that can be used to implement the system; Focuses on developing a solution that will execute in a specific environment; Enhances the description of the evolving information system; Elaboration and construction phases. 4.) Implementation Workflow: Create an executable solution based on the design model; The implementers must integrate the separate, individually tested modules to create executable solution; Elaboration and construction phases. 5.) Testing Workflow: Increase the quality of the evolving system; testing the integration of all modules used to implement the system, user acceptance testing, and the actual alpha testing of the software; Elaboration and construction phase. Deployment Workflow: Software packaging, distribution, installation, and beta testing; Transition phase. b. Supporting Workflows i. 1.) Project Management: Activities in this workflow include risk identification and management, scope management, estimating the time to complete each iteration and the entire project, estimating the cost of the individual iteration and the whole project, and tracking the progress made toward the final version of the evolving information system. 2.) Configuration and change management: to keep track of the evolving system; Artifacts (diagrams, source code, and executables) are always modified; These artifacts should be handled as any expensive asset would be handled; Access controls must be put into place to safeguard the artifacts from being stolen or destroyed; Because the artifacts are modified on a regular, if not continuous basis, good version controls mechanisms should be established; Construction and transition phases. 3.) Environment assessment: the environment workflow addresses the need for the development team to use different tools and processes; Other tools necessary include programming environments, project management tools, and configuration management tools; The workflow involves acquiring and installing these tools; Inception phase. 4.) Operations and support workflow (Production phase): Addresses issues related to supporting the current version of the software and operating the software on a daily basis; Activities include creating plans for the operation and support of the software product once it has been deployed, creating training and user documentation, putting into place necessary backup procedures, monitoring and optimizing the performance of the software, and performing of the software, and performing corrective maintenance on the software; The workflow finally drops off when the current version of the software is replaced by the new version; Once the software has been delivered to the customer, their work is NOT finished. In most cases the work of supporting the software product is much more costly and time consuming than the original development. 5.) Infrastructure Management (Production phase): To support the development of the infrastructure necessary to develop object oriented systems; Management of essential operation components, such as policies, processes, equipment, data, human resources, and external contacts, for overall effectiveness; Activities such as development and modification of libraries, standards, and enterprise models are very important; When the development and maintenance of a problem domain architecture model goes beyond the scope of a single project and reuse is going to occur, the infrastructure management workflow is essential. Improves the software development process. 3. Extensions to the unified process (or when goo methodologies turn bad) a. Net workflows: 1.) Operations and support; 2.) Infrastructure management Modifications to existing workflows: 1.) Testing workflow; 2.) Deployment workflow; 3.) Environment workflow; 4.) Project management workflow; 5.) Configuration and change management workflow. Unified Modeling Language: Provides a common vocabulary of object oriented terms and diagramming techniques. Version 2.0 has 14 diagrams in 2 major groups: Structure and behavior diagrams b. Structure Diagrams: Describes the systems in terms of attributes, methods, classes and relationships. Behavioral Diagrams: Describes the behavior of the system in terms of messages passed among objects and state changes within an object. Design approaches 1. 1.) Process centered oriented: Emphasizes process models as the core of the system concept and would focus first on defining the process. (assemble sandwich ingredients) 2.) Data Centered oriented: Emphasize data models as the core of the system and would focus on defining the contents of the storage areas. (refrigerator) 3.) Object oriented: The attempt to balance the focus between process and data by incorporating both into one model. Purpose of OOSAD 1. Reduce redundancy through reuse: Inheritance: General classes are created (superclasses); Subclasses can inherit data and methods from a superclass. Abstract classes do not produce instances because they are used merely as templates for other, more specific classes. (Person). Concrete classes are classes throughout the hierarchy that leads to instances. (Patient would be an example because they lead to instances.) Polymorphism: The same message can have a different meaning 2.) Containment: Encapsulation: Combination of data and process oriented. Information hiding: Functionality is hidden Key OOSAD Concepts 1. Classes: Generic template/ blueprint we use to create a class. Object (instance): A specific person place or thing. Attributes: Information that describes the class. Methods: The behavior of a class. Messages: Information sent to an object to trigger a method (procedure call) Characteristic of OOSAD 1. 1.) Use case driven: Use cases define the behavior of the system (user stories) Each use case focuses on one business process 2.) Architecture centric: Functional (external) view focuses on the user’s perspective. Static (structural view: focuses on attributes, methods, classes & relationships. Dynamic (behavioral) view: focuses on messages between classes and resulting behaviors. 3.) Iterative & incremental: Undergoes continuous testing and refinement. The analysts understands the system better over time. Benefits of OOSAD: Break a complex system into smaller, more manageable modules. Work on modules individually and keep them from impacting each other. See the system more realistically as the users do. Project Identification and project selections: Driven by business needs jointly by business and IT and projects are approved, declined or delayed based on value added vs risks. Choosing Projects 1. Inception Phase: Generate a system request based on a business need or opportunity a. The system request: A system request is a document that describes the business reasons for building a system and the value that the system is expected to provide. Contains 5 elements: 1.) Project sponsor: the primary point of contact for the project. 2.) Business need: The reason prompting the project. 3.) Business requirements: What the system will do; Features and capabilities of the information system. 4.) Business Value: How will the organization benefit from the project. Tangible value: Quantified and measured directly Intangible value: Add value and save time but may not be quantified or measurable. 5.) Special issues: Anything else that should be considered. 2. Perform a feasibility analysis; revise the system request: What are the risks Can these risks be overcome Good PMs constantly think about metrics. Major components are: a. Technical feasibility (Can we build it): 1). Functional area: Are analysts familiar with this portion of the business 2.) Technology: Less familiarity generates more risk 3.) Project size: Large projects have more risk. 4.) Compatibility: Difficult integration increases risk (New technology with existing technology) b. Economic Feasibility (Should we build it): 1.) Identifying cost and benefits: Development costs which are tangible costs incurred during the construction of the system. Operational costs which are tangible costs required to operate the system. Tangible benefits which are revenue and cost savings that the system enables the organization to collect. Intangible benefits are costs and benefits that are more difficult to incorporate because they are based on intuition and belief. 2.) Assign values to the cost and benefits: Work with business users and IT professionals to create numbers for each of the costs and benefits. 3.) Determining cash flow: Project what the costs and benefits will be over a period of time, usually 3-5 years. Apply growth rate to the numbers, if necessary. 4.) Determining the value use one or more methods: Net present value is the amount of an investment today compared to the same amount in the future. Return on investment measures the amount of money an organization receives in return for the money it spends. Break even point is when the returns match the amount invested in the project. c. Organizational feasibility (If we build it, will they come): How well the system ultimately be accepted by its users and incorporated into the ongoing operations of the organization. Two ways to assess the organizational feasibility is strategic alignment and stakeholder analysis. Strategic alignment is the fit between the project and the business strategy; the greater the alignment, the less risky the project will be. Stakeholder Analysis is a person, group, or organization that can affect the new system (project champion initiates the project, promotes the project, allocates his or her time to the project, and provides resources; system users makes decisions that influence the project, perform hands on activities for the project, and ultimately determine whether the project is successful by using or not using the system; organizational management are mangers that know about the project, budget enough money for the project, and encourage users to accept and use the system.) 3. Approve or decline the project (self-explanatory) Project Management tools: Identify tasks, sequence and estimate time to completion. Includes work breakdown structures, Gantt charts, and Network diagrams. 1. Work breakdown structure: A list of tasks hierarchically that identifies high level tasks and then broken down into subtasks. There are 2 basic approaches to organizing a WBS which are development phase or by product. Task: A unit of work that will be performed by a member or members of the development team, such as feasibility analysis. Task duration: How long it will take for each task to be completed. Task status: The status of a task whether it is complete, open, or in progress. Task dependencies: When one task cannot be performed until another task is completed. 2. Gantt chart: A horizontal bar chart that shows the same task information as project WBS but in a graphical way. The project manager can tell which tasks are sequential, which tasks occur at the same time, and which tasks overlap in some way. He or she can get a quick view of tasks that are ahead of schedule and behind schedule by drawing vertical line on todays date. If a bar is not filled in and is to the left of the line, the task is behind schedule. Arrows are drawn between the task bars to show task dependencies 3. Network diagrams: Lays out the project tasks in a flowchart. The network diagram is drawn as a node and arc type of graph that shows time estimates in the nodes and task dependencies on the arcs. Each node represents an individual task, and line connecting two nodes represents the dependency between two tasks. Partially completed tasks are usually displayed with a diagonal line through the node, and completed tasks contain crossed lines. Program evaluation and technique: A network analysis technique that can be used when the individual task time estimates are fairly uncertain. Critical path method: Shows all the tasks that must be completed on schedule for a project as a whole to finish on schedule. If any tasks on the critical path take longer than expected, the entire project will fall behind. Each task on the critical path is a critical task, and they are usually depicted in a unique way. Project effort estimation: Estimation is the process of assigning projected values for time and effort. The estimates developed at the start of the project are usually based on a range of possible values and gradually become more specific as the project moves forward. The science of project management is in making trade-offs among three important concepts: functionality of the system, the time to complete the project, and the cost of the project. Use case points are based on unique features of use cases and object orientation. Once the project managers find the total of both unadjusted actor weight total and unadjusted use case weight total, he adds them together to find unadjusted use case points. Use case models have two primary constructs: actors and use cases. Managers also have to measure the technical complexity and environmental factors along with the use case models. 1. 1.) Actos: People of information systems that interact with the system under development. Simple actors are separate systems with which the current system must communicate through a well-defined application program interface. Average actors: Separate systems that interact with the current system using standard communication protocols or an external database that can be accessed using standard SQL. Complex actors: Typically end users communicating with the system. Unadjusted actor weight total is computed by summing the individual results what were computed by multiplying the weighting factor by the number of actors of each type. 2.) Use cases: represents a major business process that the system will perform that benefits the actor(s) in some manner. Simple use case: Supports 1-3 transactions. Average use case: Supports 4-7 transactions. Complex use case: Supports 7 or more transactions. Unadjusted use case total: Computed by multiplying the appropriate weights and summing the results, we get the value for the unadjusted use case weight total. 3.) Technical complexity: Have to measure the complexity of the system being developed in order to measure the total effort. 4.) Environmental factors: The experience levels of the development staff. Creating and managing the workplan: A dynamic and sequential list of all tasks needed to complete the project.  1.) Approaches to creating and managing the wrokplan: Modify existing or completed projects. Derive the tasks from the methodology being used. 2.) Unified process: Workplan is also iterative & incremental. Tasks and time intervals follow the phases. Different tasks executed for each workflow. 3.) Evolutionary WBS: Has all phases in each workflow and each phase is decomposed into tasks. The workflows are the major listed points listed. Next each workflow is decomposed along the phases of the enhanced unified process. After that, each phase is decomposed along the phases of the unified process. Scope Creep: Results from adding new requirements to the project after the original project scope was defined and frozen. Effects on the schedule and cost. Project manager is responsible to manage change. To manage the scope: Identify all requirements in the beginning of the project. Allow only necessary changes deemed absolutely necessary. Any change that is implemented should be carefully tracked so that an audit trail exists to measure the change’s impact. Delay some changes for future enhancements. Time boxing: This technique sets a fixed deadline for a project and delivers the system by that deadline no matter what, even if functionality needs to be reduced. Environment & Infrastructure management:  Environment: CASE tools increase productivity and centralize information. Utilize diagrams which is more easily understood. Establish standards to reduce complexity. Upper CASE: Supports the analysis workflow by creating integrated diagrams of the system and to store information regarding the system components. Lower CASE: Supports the design workflow that can be used to generate code for database tables and system functionality. Integrated CASE: Supports both the analysis and design workflows. 2.) Infrastructure Management: Store deliverables and communications in central place. Use unified process standard documents. Don’t put off documentation to the last minute. The best PMs document as well. Staffing the Project: The goals are to 1.) Determine how many people are required. 2.) Match skill sets to required activities. 3.) Motivate the team to meet the objectives. 4.) Minimize conflicts  Staffing plan: 1.) Number & kind of people assigned: To calculate the average number of staff, divide the total person-months of effort by the optimal schedule. For example, to complete a 40 person month project in 10 months, a team should have an average of four full time staff members. 2.) Overall reporting structure: A functional lead is then assigned to manage a group of analysts and a technical lead oversees the progress of a group of programmers and more technical staff members. After leads are chosen, the project manager decides each person’s role. For example, there are technical skills that are needed. Whoever has the respected skill is filled in one or two groups. 3.) Project’s objectives and rules: After the project manager understands how many people are needed for the project, he or she creates a staffing plan that lists the roles and the proposed reporting structure that are required for the project. Jelled Team: A team of people so strongly knit that the whole is greater than the sum of its parts. Characteristics of a jelled team:  1.) Very low turnover rate: Team members feel a responsibility to other team members so they won’t quit. 2.) Strong sense of identity: Team members doing something outside of work. 3.) A feeling of eliteness: Sports teams, U.S. navy, SWAT teams. 4.) Team vs. individual ownership: Only thing that matters is the output of what the team does. 5.) Team members enjoy their work. Handling Conflict: 1.) Making sure the team understands the importance of the project. 2.) Forecast other priorities and their impact on the project. 3.) Clearly define: plans and charter, operational procedures, roles, and schedule. Motivation: Motivation is the greatest influence on performance. Monetary rewards usually do not motivate (money and bonuses) Motivating techniques: 1.) 20% rule. 2.) Peer to peer recognition. 3.) Team ownership. 4.) Allow members to focus on what interests them. 5.) Utilize equitable compensation. 6.) Encourage group ownership. 7.) Provide for autonomy, but trust them to deliver. Requirements & OOSAD: The iterative processes of OOSAD is effective because: small batches of requirements can be identified and implemented incrementally. The system will evolve over time. What is Requirements Determination: Turn very high level explanation of the business requirements stated in the system request into a more precise list of requirements that can be used as inputs to the rest of the analysis.  A requirement is a statement of what the system must do or a characteristic it must have. 1.) Business requirements: During analysis, requirements are written from the perspective of the businessperson, and they focus on the “what” of the system. Focuses the needs of the business. 2.) System requirements: Later in design, business requirements evolve to become more technical, and they describe how the system will be implemented. Requirements in design are written for the developer’s perspective. Requirement types: 1.) Functional: Relates to a process or data (Examples are searching for available inventory, reported budgeted expenses, chuck pumpkin) 2.) Non-functional: Relates to performance or usability (Examples are easy to read for older users, secure from hackers, chuck pumpkin really fast. Requirements definition: A straightforward text report that simply lists the functional and non-functional requirements in an outline format that is applicable to the project. The requirements definition is kept up to date so that the project team and business users can refer to it and get a clear understanding of the new system. Sometimes business requirements are prioritized on the requirements definition. They can be ranked as high, medium, or low.  Requirements definition steps: 1.) Determine the types of functional and non-functional requirements applicable to the project. 2.) Use requirements-gathering techniques. 3.) Verify, change and prioritize each requirement. 4.) Iterate through analysis workflow, beware of scope creep. The project team carefully identifies and evaluates each requirement as time goes on to see which one fits within the scope of the system. Requirements that meet need but are outside current scope added to list of future enhancements. Determining requirements: Determining requirements for the requirements definition is both a business task and information technology task. Techniques are Interviews, questionnaires, observation, JAD, and document analysis Problems in determining requirements: 1.) Analyst may not have access to the correct users. 2.) Requirements may not be known in the beginning. 3.) Some requirements may not be known in the beginning. 4.) Verifying and validating requirements can be difficult. Requirements Analysis strategies: 1.) Business process automation: Critically examine the current state of systems and processes (Small amount of change). 2 types of BPA techniques are problem analysis and root cause analysis. Problem analysis: Ask users and managers to identify problem with the current system. Ask user and managers how they would solve these problems. This type of analysis is very effective at improving a system’s efficiency of ease of use. Root cause analysis: Focus is on the cause of a problem not its solution. Create a prioritized list of problems. Try to determine their causes. Once the causes are known, solutions can be developed. 2.) Business process improvement: Identify exactly what needs to change (Moderate change). 3 types of BPI techniques are duration analysis, Activity based costing and benchmarking.. Duration analysis: For example, suppose that the analysts are working on a home mortgage system and discover that on average, it takes 30 days for the bank to approve a mortgage. Then they look at each basic step and find out that it only takes 8 hours. This is a strong indication that the overall process is badly broken, because it takes 30 days to perform 1 days work. Process integration means changing the fundamental process so that fewer work on the input, which often requires changing the process and retraining staff to perform wider range of duties. Process parallelization means changing the process so that all individual tasks are performed at the same time. 3.) Business process reengineering: Develop a concept for a new system (Significant change that affects much of the organization). 3 types of BPR techniques are outcome analysis, technology analysis, and activity elimination. Outcome analysis (what does the customer want in the end) focuses on understanding the fundamental outcome that provide value to customers. (Insurance company and car accident). Technology analysis (apply new technologies to business processes & identify benefits) starts by having the analysts and managers develop a list of important and interesting technologies. Then the group systematically identifies how every technology could be applied to the business process and identifies how the business would benefit. Activity elimination: The analysts and managers work together to identify how the organization could eliminate each activity in the business process, how the function could operate without it, and what effects are likely to occur. Selecting the right strategy: 1.) Potential business value: BPA: Has the potential to improve the business, most of the benefits from BPA are tactical and small. Because BPA does not seek to change the business processes, it can only improve their efficiency. BPI: Offers moderate potential benefits, depending upon the scope of the project, because it seeks to change the business in some way. It can increase both efficiency and effectiveness. BPR: Creates large potential benefits because it seeks radically improve the nature of the business. 2.) Project cost: BPA: Has the lowest cost because it has the narrowest focus and seeks to make the fewest changes. BPI: Moderately expensive, depending upon the scope of the project. BPR: Usually expensive, because of the amount of time required of senior managers and the amount of redesign to business processes. 3.) Breadth analysis: Refers to the scope of analysis, or whether analysis includes business processes within a single business function, processes that cross organization, or processes that interact with those in customer or supplier organizations. BPA: Typically examines a single process. BPI: Narrow scope that usually includes one or several nosiness functions. BPR: Broad perspective, often spanning several major business processes, even across multiple organizations. 4.) Risk: Rick of failure, which is likelihood of failure due to poor design, unmet needs, or too much change for the organization to handle. BPA and BPI: Low moderate risk because the to-be system is fairly well defined and well understood, and its potential impact on the business can be accessed before it is implemented. BPR: Extremely risky and is not something to be undertaken unless the organization and its senior leadership are committed to making significant changes. Requirements gathering tools process: 1.) The requirements gathering process is used for building political support for the project and establishing trust and rapport between the project team building the system and the users who ultimately will choose to use or not use the system. Involving someone in the process implies that the project teams view that person as an important resource and value his or her opinions. If a key person is not involved, that individual might feel slighted, which can cause problems during implementation. 2.) The second challenge of requirements gathering is choosing the way(s) information is collected. There are many techniques for gathering requirements that vary from asking people questions to watching them work. Comparing requirements gathering techniques: 1.) Depth of information: The depth of information refers to how rich and detailed information is that the technique usually produces and the extent to which the technique is useful for obtaining not only facts and opinions but also understanding of why those facts and opinions exist. Interviews and JAD sessions are very useful for providing a good depth of rich and detailed information. Breadth of information: Refers to the range of information and information sources that can be easily collected using the chose technique. Questionnaires and document analysis are both easily capable of soliciting a wide range of information from a large number of information sources. Integration of information: One of the most challenging aspects of requirements gathering is integrating the information from different sources. Simply put, different people can provide conflicting information. Combining this information and attempting to resolve differences in opinions or facts is usually very time consuming because it means contacting each information source in turn, explaining the discrepancy, and attempting to refine the information. User involvement: Refers to the amount of time and energy the intended users of the new system must devote to the analysis process. It is generally agreed that as users become more involved in the analysis process, the chance of success increases. Alternative techniques: 1.) Concept maps: Represent meaningful relationships between concepts. They are useful for focusing individuals on the small number of key ideas on which they should concentrate. A concept map is essentially a node and arc representation, where the nodes represent the individual requirements and the arcs represent the relationships among the requirements. Concept maps allow relationships among the functional and non-functional requirements to be explicitly represented. 2.) Story cards and task lists: A story card is typically an index card with a single requirement (functional or non-functional) written on it. Once the requirement is written down, it is discussed to determine the amount of effort it will take to implement it. A task list is created for the requirement. Advantages of using story cards and task lists to document requirements is that they are very easy in every way. Systems Development Life Cycle 1. Planning Phase: Why should we build this system What value does it provide How long will it take to build 2 phases in planning are: 1. 1.) Project Initiation: The system’s business value to the organization is identified. System Request: A request presents a brief summary of a business need, and it explains how a system that supports the need will create business value. Feasibility Analysis: Can we build it Will it provide business value If we build it, will it be used 2.) Project Management: A project plan, which describes how the project team will go about developing the system. A project manager creates a work plan, staffs the project, and puts techniques in place to help the project team control and direct the project through the entire SDLC. (Staffing Budgeting, Contract, management, Maintenance, operations and support, cross or inter project issues) 2. Analysis Phase: Who will use it specifically What should the system do for us Where & when will it be used 3 phases in analysis are: 1. 1.) Analysis Strategy: An analysis of the current system (as-is system) and its problems and then ways to design a new system (to-be system) Requirements Gathering: Through interviews, questionnaires, and input from project sponsor and many other people, this leads to the development of a concept for a new system. Analysis Models: The set of models typically includes models that represent the data and processes necessary to support the underlying business process. 2.) System Proposal: Presented to the project sponsor and other key decision makers who decide whether the project continue to move forward. 3. Design Phase: How the system will operate in terms of the hardware, software and network infrastructure; the user interface; forms and reports; and the specific programs, databases, and files that will be needed. 4 phases in the design phase are: 1. 1.) Design Strategy: It clarifies whether the system will be developed by the company’s own programmers, whether the system will be outsourced to another firm, or whether the company will buy an existing software package. 2.) Design Architecture: Describes the hardware, software, and network infrastructure to be used. Interface Design: Specifies how the users will more through the system (navigation methods such as menus and on-screen buttons) and the forms and reports that the system will use. 3.) Database and file specifications: This defines exactly what data will be stored and where they will be stored. 4.) Program specifications/designs: Defines the programs that need to be written and exactly what each program will do. 4. Implementation: 4 phases in the implementation phase are: 1. 1.) Construction: The system is built and tested to ensure it performs as designed. Testing is one of the most critical steps in implementation. 2.) Installation: The process by which the old system is turned off and the new one is turned on. 3.) Training plan: To each users how to use the new system and help manage the changes caused by the new system. 4.) Support plan: Post implementation review as well as systematic way for identifying major and minor changes needed for the system. Methodologies 1. Structured Development: A formal step by step approach to the SDLC that moves logically from one phase to the next. (Waterfall, Parallel) 2. Rapid application development: It attempts to address both weaknesses of structured design methodologies by adjusting the SDLC phases to get some part of the system developed quickly and into the hands of the users. In this way, the users can better understand the system and suggest revisions that bring the system closer to what is needed. Phased, prototyping throwaway prototyping) 3. Agile Development: Focus the developers on the working conditions of the developers, the working software, the customers, and addressing changing requirements instead of focusing on detailed systems development processes, tools all inclusive documentation, legal contracts, and detailed plans. (Extreme programming, scrum) The unified process: A specific methodology that maps out when and how to use the various UML techniques for object oriented analysis and design. A two dimensional process consisting of phases and workflows. 1. Unified phases process: The time periods in development. a. Inception phase: Performs the feasibility analysis. Workflows vary but focus is on business modeling and requirements gathering. Elaboration phase: Heavy focus on analysis and design. Other workflows may be included. Construction phase: Focuses on programming. (implementation) Transition phase: Focus on testing and deployment 2. Workflows are the tasks that occur in each phase. Activities in both phases & workflows will overlap. a. Engineering Workflows i. 1.) Business Modeling Workflow: Uncovers problems and identifies potential projects within a user organization. Understanding the scope of the projects that can improve the efficiency and effectiveness of a user organization. Ensure that both the developer and user organizations understand where and how the to-be developed information system fits into the business processes of the organization. Inception phase. 2.) Requirements Workflow: Eliciting both functional and nonfunctional requirements. Different ways to capture requirements such as interviewing, observation techniques, join application development, document analysis, and questionnaires. Very helpful for developing the vision document and the use cases used throughout the development process. Inception and elaboration phase. Analysis Workflow: Addresses the creation of analysis model of the problem domain; The analyst creates structural and behavior diagrams that depict a description of the problem domain classes and their interactions; The primary purpose of the analysis workflow is to ensure that both the developer and user organizations understand the underlying problem and its domain without overanalyzing; Understanding the problem domain; Elaboration phase. 3.) Design Workflow: Transitions the analysis model into a form that can be used to implement the system; Focuses on developing a solution that will execute in a specific environment; Enhances the description of the evolving information system; Elaboration and construction phases. 4.) Implementation Workflow: Create an executable solution based on the design model; The implementers must integrate the separate, individually tested modules to create executable solution; Elaboration and construction phases. 5.) Testing Workflow: Increase the quality of the evolving system; testing the integration of all modules used to implement the system, user acceptance testing, and the actual alpha testing of the software; Elaboration and construction phase. Deployment Workflow: Software packaging, distribution, installation, and beta testing; Transition phase. b. Supporting Workflows i. 1.) Project Management: Activities in this workflow include risk identification and management, scope management, estimating the time to complete each iteration and the entire project, estimating the cost of the individual iteration and the whole project, and tracking the progress made toward the final version of the evolving information system. 2.) Configuration and change management: to keep track of the evolving system; Artifacts (diagrams, source code, and executables) are always modified; These artifacts should be handled as any expensive asset would be handled; Access controls must be put into place to safeguard the artifacts from being stolen or destroyed; Because the artifacts are modified on a regular, if not continuous basis, good version controls mechanisms should be established; Construction and transition phases. 3.) Environment assessment: the environment workflow addresses the need for the development team to use different tools and processes; Other tools necessary include programming environments, project management tools, and configuration management tools; The workflow involves acquiring and installing these tools; Inception phase. 4.) Operations and support workflow (Production phase): Addresses issues related to supporting the current version of the software and operating the software on a daily basis; Activities include creating plans for the operation and support of the software product once it has been deployed, creating training and user documentation, putting into place necessary backup procedures, monitoring and optimizing the performance of the software, and performing of the software, and performing corrective maintenance on the software; The workflow finally drops off when the current version of the software is replaced by the new version; Once the software has been delivered to the customer, their work is NOT finished. In most cases the work of supporting the software product is much more costly and time consuming than the original development. 5.) Infrastructure Management (Production phase): To support the development of the infrastructure necessary to develop object oriented systems; Management of essential operation components, such as policies, processes, equipment, data, human resources, and external contacts, for overall effectiveness; Activities such as development and modification of libraries, standards, and enterprise models are very important; When the development and maintenance of a problem domain architecture model goes beyond the scope of a single project and reuse is going to occur, the infrastructure management workflow is essential. Improves the software development process. 3. Extensions to the unified process (or when goo methodologies turn bad) a. Net workflows: 1.) Operations and support; 2.) Infrastructure management Modifications to existing workflows: 1.) Testing workflow; 2.) Deployment workflow; 3.) Environment workflow; 4.) Project management workflow; 5.) Configuration and change management workflow. Unified Modeling Language: Provides a common vocabulary of object oriented terms and diagramming techniques. Version 2.0 has 14 diagrams in 2 major groups: Structure and behavior diagrams b. Structure Diagrams: Describes the systems in terms of attributes, methods, classes and relationships. Behavioral Diagrams: Describes the behavior of the system in terms of messages passed among objects and state changes within an object. Design approaches 1. 1.) Process centered oriented: Emphasizes process models as the core of the system concept and would focus first on defining the process. (assemble sandwich ingredients) 2.) Data Centered oriented: Emphasize data models as the core of the system and would focus on defining the contents of the storage areas. (refrigerator) 3.) Object oriented: The attempt to balance the focus between process and data by incorporating both into one model. Purpose of OOSAD 1. Reduce redundancy through reuse: Inheritance: General classes are created (superclasses); Subclasses can inherit data and methods from a superclass. Abstract classes do not produce instances because they are used merely as templates for other, more specific classes. (Person). Concrete classes are classes throughout the hierarchy that leads to instances. (Patient would be an example because they lead to instances.) Polymorphism: The same message can have a different meaning 2.) Containment: Encapsulation: Combination of data and process oriented. Information hiding: Functionality is hidden Key OOSAD Concepts 1. Classes: Generic template/ blueprint we use to create a class. Object (instance): A specific person place or thing. Attributes: Information that describes the class. Methods: The behavior of a class. Messages: Information sent to an object to trigger a method (procedure call) Characteristic of OOSAD 1. 1.) Use case driven: Use cases define the behavior of the system (user stories) Each use case focuses on one business process 2.) Architecture centric: Functional (external) view focuses on the user’s perspective. Static (structural view: focuses on attributes, methods, classes & relationships. Dynamic (behavioral) view: focuses on messages between classes and resulting behaviors. 3.) Iterative & incremental: Undergoes continuous testing and refinement. The analysts understands the system better over time. Benefits of OOSAD: Break a complex system into smaller, more manageable modules. Work on modules individually and keep them from impacting each other. See the system more realistically as the users do. Project Identification and project selections: Driven by business needs jointly by business and IT and projects are approved, declined or delayed based on value added vs risks. Choosing Projects 1. Inception Phase: Generate a system request based on a business need or opportunity a. The system request: A system request is a document that describes the business reasons for building a system and the value that the system is expected to provide. Contains 5 elements: 1.) Project sponsor: the primary point of contact for the project. 2.) Business need: The reason prompting the project. 3.) Business requirements: What the system will do; Features and capabilities of the information system. 4.) Business Value: How will the organization benefit from the project. Tangible value: Quantified and measured directly Intangible value: Add value and save time but may not be quantified or measurable. 5.) Special issues: Anything else that should be considered. 2. Perform a feasibility analysis; revise the system request: What are the risks Can these risks be overcome Good PMs constantly think about metrics. Major components are: a. Technical feasibility (Can we build it): 1). Functional area: Are analysts familiar with this portion of the business 2.) Technology: Less familiarity generates more risk 3.) Project size: Large projects have more risk. 4.) Compatibility: Difficult integration increases risk (New technology with existing technology) b. Economic Feasibility (Should we build it): 1.) Identifying cost and benefits: Development costs which are tangible costs incurred during the construction of the system. Operational costs which are tangible costs required to operate the system. Tangible benefits which are revenue and cost savings that the system enables the organization to collect. Intangible benefits are costs and benefits that are more difficult to incorporate because they are based on intuition and belief. 2.) Assign values to the cost and benefits: Work with business users and IT professionals to create numbers for each of the costs and benefits. 3.) Determining cash flow: Project what the costs and benefits will be over a period of time, usually 3-5 years. Apply growth rate to the numbers, if necessary. 4.) Determining the value use one or more methods: Net present value is the amount of an investment today compared to the same amount in the future. Return on investment measures the amount of money an organization receives in return for the money it spends. Break even point is when the returns match the amount invested in the project. c. Organizational feasibility (If we build it, will they come): How well the system ultimately be accepted by its users and incorporated into the ongoing operations of the organization. Two ways to assess the organizational feasibility is strategic alignment and stakeholder analysis. Strategic alignment is the fit between the project and the business strategy; the greater the alignment, the less risky the project will be. Stakeholder Analysis is a person, group, or organization that can affect the new system (project champion initiates the project, promotes the project, allocates his or her time to the project, and provides resources; system users makes decisions that influence the project, perform hands on activities for the project, and ultimately determine whether the project is successful by using or not using the system; organizational management are mangers that know about the project, budget enough money for the project, and encourage users to accept and use the system.) 3. Approve or decline the project (self-explanatory) Project Management tools: Identify tasks, sequence and estimate time to completion. Includes work breakdown structures, Gantt charts, and Network diagrams. 1. Work breakdown structure: A list of tasks hierarchically that identifies high level tasks and then broken down into subtasks. There are 2 basic approaches to organizing a WBS which are development phase or by product. Task: A unit of work that will be performed by a member or members of the development team, such as feasibility analysis. Task duration: How long it will take for each task to be completed. Task status: The status of a task whether it is complete, open, or in progress. Task dependencies: When one task cannot be performed until another task is completed. 2. Gantt chart: A horizontal bar chart that shows the same task information as project WBS but in a graphical way. The project manager can tell which tasks are sequential, which tasks occur at the same time, and which tasks overlap in some way. He or she can get a quick view of tasks that are ahead of schedule and behind schedule by drawing vertical line on todays date. If a bar is not filled in and is to the left of the line, the task is behind schedule. Arrows are drawn between the task bars to show task dependencies 3. Network diagrams: Lays out the project tasks in a flowchart. The network diagram is drawn as a node and arc type of graph that shows time estimates in the nodes and task dependencies on the arcs. Each node represents an individual task, and line connecting two nodes represents the dependency between two tasks. Partially completed tasks are usually displayed with a diagonal line through the node, and completed tasks contain crossed lines. Program evaluation and technique: A network analysis technique that can be used when the individual task time estimates are fairly uncertain. Critical path method: Shows all the tasks that must be completed on schedule for a project as a whole to finish on schedule. If any tasks on the critical path take longer than expected, the entire project will fall behind. Each task on the critical path is a critical task, and they are usually depicted in a unique way. Project effort estimation: Estimation is the process of assigning projected values for time and effort. The estimates developed at the start of the project are usually based on a range of possible values and gradually become more specific as the project moves forward. The science of project management is in making trade-offs among three important concepts: functionality of the system, the time to complete the project, and the cost of the project. Use case points are based on unique features of use cases and object orientation. Once the project managers find the total of both unadjusted actor weight total and unadjusted use case weight total, he adds them together to find unadjusted use case points. Use case models have two primary constructs: actors and use cases. Managers also have to measure the technical complexity and environmental factors along with the use case models. 1. 1.) Actos: People of information systems that interact with the system under development. Simple actors are separate systems with which the current system must communicate through a well-defined application program interface. Average actors: Separate systems that interact with the current system using standard communication protocols or an external database that can be accessed using standard SQL. Complex actors: Typically end users communicating with the system. Unadjusted actor weight total is computed by summing the individual results what were computed by multiplying the weighting factor by the number of actors of each type. 2.) Use cases: represents a major business process that the system will perform that benefits the actor(s) in some manner. Simple use case: Supports 1-3 transactions. Average use case: Supports 4-7 transactions. Complex use case: Supports 7 or more transactions. Unadjusted use case total: Computed by multiplying the appropriate weights and summing the results, we get the value for the unadjusted use case weight total. 3.) Technical complexity: Have to measure the complexity of the system being developed in order to measure the total effort. 4.) Environmental factors: The experience levels of the development staff. Creating and managing the workplan: A dynamic and sequential list of all tasks needed to complete the project.  1.) Approaches to creating and managing the wrokplan: Modify existing or completed projects. Derive the tasks from the methodology being used. 2.) Unified process: Workplan is also iterative & incremental. Tasks and time intervals follow the phases. Different tasks executed for each workflow. 3.) Evolutionary WBS: Has all phases in each workflow and each phase is decomposed into tasks. The workflows are the major listed points listed. Next each workflow is decomposed along the phases of the enhanced unified process. After that, each phase is decomposed along the phases of the unified process. Scope Creep: Results from adding new requirements to the project after the original project scope was defined and frozen. Effects on the schedule and cost. Project manager is responsible to manage change. To manage the scope: Identify all requirements in the beginning of the project. Allow only necessary changes deemed absolutely necessary. Any change that is implemented should be carefully tracked so that an audit trail exists to measure the change’s impact. Delay some changes for future enhancements. Time boxing: This technique sets a fixed deadline for a project and delivers the system by that deadline no matter what, even if functionality needs to be reduced. Environment & Infrastructure management:  Environment: CASE tools increase productivity and centralize information. Utilize diagrams which is more easily understood. Establish standards to reduce complexity. Upper CASE: Supports the analysis workflow by creating integrated diagrams of the system and to store information regarding the system components. Lower CASE: Supports the design workflow that can be used to generate code for database tables and system functionality. Integrated CASE: Supports both the analysis and design workflows. 2.) Infrastructure Management: Store deliverables and communications in central place. Use unified process standard documents. Don’t put off documentation to the last minute. The best PMs document as well. Staffing the Project: The goals are to 1.) Determine how many people are required. 2.) Match skill sets to required activities. 3.) Motivate the team to meet the objectives. 4.) Minimize conflicts  Staffing plan: 1.) Number & kind of people assigned: To calculate the average number of staff, divide the total person-months of effort by the optimal schedule. For example, to complete a 40 person month project in 10 months, a team should have an average of four full time staff members. 2.) Overall reporting structure: A functional lead is then assigned to manage a group of analysts and a technical lead oversees the progress of a group of programmers and more technical staff members. After leads are chosen, the project manager decides each person’s role. For example, there are technical skills that are needed. Whoever has the respected skill is filled in one or two groups. 3.) Project’s objectives and rules: After the project manager understands how many people are needed for the project, he or she creates a staffing plan that lists the roles and the proposed reporting structure that are required for the project. Jelled Team: A team of people so strongly knit that the whole is greater than the sum of its parts. Characteristics of a jelled team:  1.) Very low turnover rate: Team members feel a responsibility to other team members so they won’t quit. 2.) Strong sense of identity: Team members doing something outside of work. 3.) A feeling of eliteness: Sports teams, U.S. navy, SWAT teams. 4.) Team vs. individual ownership: Only thing that matters is the output of what the team does. 5.) Team members enjoy their work. Handling Conflict: 1.) Making sure the team understands the importance of the project. 2.) Forecast other priorities and their impact on the project. 3.) Clearly define: plans and charter, operational procedures, roles, and schedule. Motivation: Motivation is the greatest influence on performance. Monetary rewards usually do not motivate (money and bonuses) Motivating techniques: 1.) 20% rule. 2.) Peer to peer recognition. 3.) Team ownership. 4.) Allow members to focus on what interests them. 5.) Utilize equitable compensation. 6.) Encourage group ownership. 7.) Provide for autonomy, but trust them to deliver. Requirements & OOSAD: The iterative processes of OOSAD is effective because: small batches of requirements can be identified and implemented incrementally. The system will evolve over time. What is Requirements Determination: Turn very high level explanation of the business requirements stated in the system request into a more precise list of requirements that can be used as inputs to the rest of the analysis.  A requirement is a statement of what the system must do or a characteristic it must have. 1.) Business requirements: During analysis, requirements are written from the perspective of the businessperson, and they focus on the “what” of the system. Focuses the needs of the business. 2.) System requirements: Later in design, business requirements evolve to become more technical, and they describe how the system will be implemented. Requirements in design are written for the developer’s perspective. Requirement types: 1.) Functional: Relates to a process

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Chapter 6, Problem 63E is Solved
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Textbook: Chemistry: The Central Science
Edition: 12
Author: Theodore E. Brown; H. Eugene LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward
ISBN: 9780321696724

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Many-Electron Atoms and Electron Configurations | Ch 6 - 63E