System Acquisition Strategies PDF

From Last week…. © Copyright 2011 John Wiley & Sons, Inc. 2-0 – Use Cases Elements of a use case. Alternative use case formats. Use cases and functional requirements. Use cases and testing. Building use cases – identify the triggering event,...

From Last week…. © Copyright 2011 John Wiley & Sons, Inc. 2-0 – Use Cases Elements of a use case. Alternative use case formats. Use cases and functional requirements. Use cases and testing. Building use cases – identify the triggering event, – develop a list of the major steps, – identify the input(s) and output(s) for every step, – have the users role-play the use case to verify – Data flow diagrams. Reading data flow diagrams Elements of data flow diagrams – processes, data flows, data stores, and external entities Using data flow diagrams to define business processes Process descriptions © Copyright 2011 John Wiley & Sons, Inc. 3-1 – Creating data flow diagrams The DFDs are created from use cases. Every set of DFDs starts with a context diagram. DFDs segments are created for each use case, and are then organized into a level 0 DFD. Level 1 DFDs are developed on the basis of the steps within each use case. The set of DFDs are validated to make sure that they are complete and correct and contain no syntax or semantics errors. – The Entity Relationship Diagram (ERD) Elements of ERD – Entity, Attribute, Relationship The Data Dictionary and Metadata Creating an Entity Relationship Diagram. – Identify the entities. – Add the attributes to each entity. – Draw relationships among entities Validating an ERD © Copyright 2011 John Wiley & Sons, Inc. 3-2  Validating an ERD – Normalization – CRUD matrix © Copyright 2011 John Wiley & Sons, Inc. 3-3 Moving into Design © Copyright 2011 John Wiley & Sons, Inc. 7-4  Outline ▪ Transition from requirements to design. ▪ System acquisition strategies. - Custom development. - Packaged software. - Outsourcing. ▪Influences on the acquisition strategies. ▪Selecting an acquisition strategy. © Copyright 2011 John Wiley & Sons, Inc. 7-5  INTRODUCTION ▪ The design phase decides how the new system will operate. ▪ The design phase develops the system requirements that describe details for building the system. ▪ We also describe three alternative strategies for acquiring the system. © Copyright 2011 John Wiley & Sons, Inc. 7-6 TRANSITION FROM REQUIREMENT TO DESIGN ▪ The purpose of the analysis phase is to figure out what the business needs. The purpose of the design phase is to decide how to build it. ▪ During the initial part of design, the business requirements are converted into system requirements that describe the technical details for building the system. ▪ System requirements are communicated through a collection of design documents and physical process and data models. © Copyright 2011 John Wiley & Sons, Inc. 7-7 (cont’d) ▪ Activities of the design phase © Copyright 2011 John Wiley & Sons, Inc. 7-8 (cont’d) ▪ At the end of the design phase, the final deliverable called system specification is created. ▪ System specification outline © Copyright 2011 John Wiley & Sons, Inc. 7-9 SYSTEM ACQUISITION STRATEGIES ▪There are three primary ways to approach the creation of a new system: 1. Develop a custom application in-house. 2. Buy a packaged system and (possibly) customize it; and 3. Rely on an external vendor, developer, or service provider to build or provide the system. © Copyright 2011 John Wiley & Sons, Inc. 7-10  Custom Development ▪ Custom development – building a new system from scratch. ▪ Pros of custom development: - It allows developers to be flexible and creative in the way they solve business problems. - It allows to take advantage of current technologies that can support strategic efforts. - It builds technical skills and functional knowledge within the organization. © Copyright 2011 John Wiley & Sons, Inc. 7-11 (cont’d) ▪ Cons of custom development: - It requires a dedicated effort that include long hours and hard work. - It requires a variety of skills, but high skilled IS professionals are difficult to hire and retain. - The risks associated with building a system from the ground up can be quite high. © Copyright 2011 John Wiley & Sons, Inc. 7-12  Packaged Software ▪ Many organizations buy packaged software that has been written for common business needs. ▪ It can be much more efficient to buy programs that have already been created and tested, and a packaged system can be bought and installed quickly compared with a custom system. ▪ Packaged software can range from small single- function tools to huge all-encompassing system such as ERP (enterprise resource planning) applications. © Copyright 2011 John Wiley & Sons, Inc. 7-13 (cont’d) ▪ One problem of packaged software is that companies utilizing packaged software must accept the functionality that is provided by the system. ▪ Most packaged applications allow for customization or the manipulation of system parameters to change the way certain features work. ▪ A custom-built add-on program that interfaces with the packaged application, called a workaround, can be created to handle special needs. © Copyright 2011 John Wiley & Sons, Inc. 7-14 (cont’d) ▪ Systems Integration refers to the process of building new systems by combining packaged software, existing legacy systems, and new software written to integrate them. ▪ The key challenge in systems integration is finding ways to integrate the data produced by the different packages and legacy systems. © Copyright 2011 John Wiley & Sons, Inc. 7-15  Outsourcing ▪ Outsourcing means hiring an external vendor, developer, or service provider to create or supply the system. ▪ Outsourcing firms called application service providers (ASPs) supply software applications and/or services over the Internet. ▪ Software as a service (SaaS) is an extension of the ASP model. ▪ Outsourcing has many advantages such as a low cost of entry and a short setup time. © Copyright 2011 John Wiley & Sons, Inc. 7-16 (cont’d) ▪ Risks of outsourcing: – Compromising confidential information – Losing control over future development – Losing important skills of in-house professionals. ▪ You should never outsource what you do not understand. ▪ Carefully choose an outsourcing firm with a proven track record. © Copyright 2011 John Wiley & Sons, Inc. 7-17 (cont’d) ▪ Three types of outsourcing contracts: - Time and arrangements: pay for whatever time and expenses are needed to get the job done. - Fixed-price contract - Value-added contract: the outsourcer reaps some percentage of the completed system’s benefits. © Copyright 2011 John Wiley & Sons, Inc. 7-18 (cont’d) Outsourcing Guidelines © Copyright 2011 John Wiley & Sons, Inc. 7-19  INFLUENCES ON THE ACQUISTION STRATEGY Project characteristics that influence the choice of acquisition strategy © Copyright 2011 John Wiley & Sons, Inc. 7-20  Business Need ▪ If the business need for the system is common and the technical solutions already exist, packaged software is a solution. ▪ A custom solution should be explored when the business need is unique. ▪ Outsourcing is used in situations where the business need is not a critical element of company strategy. © Copyright 2011 John Wiley & Sons, Inc. 7-21  In-House Experience ▪If in-house experience exists for all the functional and technical needs of the system, it will be easier to build a custom application. ▪A packaged system may be a better alternative for companies that do not have the technical skills to build the desired system. © Copyright 2011 John Wiley & Sons, Inc. 7-22  Project Skills ▪The skills that are applied during projects are either technical (e.g., SQL) or functional (e.g., e-commerce). ▪Different design alternatives are more viable, depending on how important the skills are to the company’s strategy. © Copyright 2011 John Wiley & Sons, Inc. 7-23  Project Management ▪Custom applications require excellent project management and a proven methodology. ▪There are so many things that can push a project off track, such as funding obstacles, staffing, and overly demanding business users. © Copyright 2011 John Wiley & Sons, Inc. 7-24 (cont’d) ▪ The project team should choose to develop a custom application only if it is certain that the underlying coordination and control mechanisms will be in place. ▪ Packaged and outsourcing alternatives also must be managed; however, they are more shielded from internal obstacles. © Copyright 2011 John Wiley & Sons, Inc. 7-25  Time Frame ▪ When time is a factor, the project team should probably start looking for a system that is already built and tested. ▪ If a custom alternative is chosen, and the time frame is very short, consider using techniques like timeboxing to manage the problem. ▪ An outsourcing solution could take as long a custom development initiative. © Copyright 2011 John Wiley & Sons, Inc. 7-26  SELECTING AN ACQUISITION STRATEGY ▪ To implement the strategies, additional information is needed. - What tools and technologies are needed for a custom development project? - What vendors make products that address the project needs? - What service providers would be able to build this application if outsourced? ▪ One helpful tool is the request for proposal (RFP), a document that solicits a formal proposal from a potential vendor, developer, or service provider. © Copyright 2011 John Wiley & Sons, Inc. 7-27 (cont’d) ▪ RFPs describe in detail the system or service that is needed, and vendor respond by describing in detail how they could supply those needs. ▪ For smaller projects with smaller budgets, a request for information (RFI) may be sufficient, as it is shorter and less detailed. ▪ When a list of equipment is so complete that the vendor needs only provide a price, a request for quote (RFQ) may be used. © Copyright 2011 John Wiley & Sons, Inc. 7-28 Developing an Alternative Matrix ▪ The alternative matrix combines several feasibility analyses into one matrix. ▪ It contains technical, economical and organizational feasibilities for each system candidate, pros and cons, and other information. ▪ The matrix is a grid with alternatives across the top and different criteria along the side. © Copyright 2011 John Wiley & Sons, Inc. 7-29 (cont’d) ▪Sometimes, weights and scores are added to create a weighted alternative matrix. ▪The score assigned is a subjective assignment. ▪To avoid a biased analysis, each analyst develops ratings independently. © Copyright 2011 John Wiley & Sons, Inc. 7-30 (cont’d) Sample Alternative Matrix Using Weights © Copyright 2011 John Wiley & Sons, Inc. 7-31 (cont’d) ▪ Influences on acquisition strategy - Each acquisition strategy has its strengths and weaknesses. - Consider such issues as the uniqueness of business need, in-house experiences, and the importance of project skills. ▪ Selecting a acquisition strategy - An alternative matrix can help the design team make the decision regarding the specific acquisition strategy. - The request for proposal and request for quote are ways to gather accurate details regarding the alternatives. © Copyright 2011 John Wiley & Sons, Inc. 7-32  SUMMARY ▪ Transitioning from requirements to design - The design phase develops the blueprint for the new system. - The main deliverable from the design phase is the system specification. ▪ System acquisition strategies - Custom application in-house. - Packaged system. - Outsourcing. © Copyright 2011 John Wiley & Sons, Inc. 7-33 Copyright 2011 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for redistribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein. © Copyright 2011 John Wiley & Sons, Inc. 7-34