Dynamic Systems Development Method and Methodology Essay Sample
There are many methodological analysiss to systems analysis and design. Each methodological analysis differs from the other in many facets including proficient attacks. position of users and system environment. epistemology and ontology. suitableness for usage. etc. Hence a more structured and formal manner of measuring methodological analysiss is by utilizing the Normative Information Model-based Systems Analysis and Design ( NIMSAD ) .
NIMSAD is good noted to hold a “wide range. non restricted to any peculiar class of methodological analysiss. practical and considers different usage situations” ( Koskinen. Lintinen. Sivula and Tilus. 2003 ) . In this paper. two methodological analysiss are compared utilizing the NIMSAD model. the Structured System Analysis and Design Method ( SSADM ) from the waterfall attack household and the Dynamic Systems Development Methodology ( DSDM ) from the nimble methodological analysis household.
Structured System Analysis and Design Method ( SSADM )
SSADM is a structured waterfall attack to systems analysis and design. It uses three chief techniques ; logical informations mold. informations flow mold and entity behaviour mold. There are seven phases to this methodological analysis get downing from phase 0 to present 6:
Phase 0: Feasibility Study
In this phase ends and deductions of the undertaking are investigated. Four chief constituents are taken into consideration: proficient. functional. organisational and ethical constituents. System demands are analyzed and concern options are identified. The terminal merchandise of this phase is a feasibleness survey papers. ( Wikipedia. 2012 )
Phase 1: Probe of the Current Environment
Data demands are investigated. A system analyst attempts to analyse the current system by agencies of “interviewing employees. go arounding questionnaires. observations and bing documentation” ( Wikipedia. 2012 ) . The aims of this probe is to happen out “ what users do and how they do it. nucleus demands for the new system. informations theoretical account building and to specify system boundaries” ( Wikipedia. 2012 ) . The terminal merchandises of this phase are a user catalog. demands catalog and a first set of informations flow diagrams ( Wikipedia. 2012 ) .
Phase 2: Business System Options
The analyst may show a set of different concern options. These options consider the “degree of mechanization. boundary between the system and the users. distribution of the system. cost and benefit of the new system and concern impact of the new system” ( Wikipedia. 2012 ) . In the terminal. stakeholders and analyst choose a individual option.
Phase 3: Requirements Specification
Here. a full logical system specification ( description of what the system must make ) is developed based on demands set in phase 1 and chosen concern option. Logical theoretical accounts of informations flow diagrams and entity relational diagrams are developed. The terminal merchandise of this phase is a full demands specifications papers ( Wikipedia. 2012 ) .
Phase 4: Technical System Options
Technical system options for systems execution are presented. Areas of consideration are the “hardware architectures. package to utilize. the cost of the execution. the staffing required. the physical restrictions. the distribution including any webs which that may necessitate and the overall format of the human computing machine interface” ( Wikipedia. 2012 ) . From that. a proficient system is chosen.
Phase 5: Logical Design
Here. the logical design is focused on the demands for human computing machine interface. The terminal merchandises are a “data catalog. required logical informations construction and logical procedure model” ( Wikipedia. 2012 ) .
Phase 6: Physical Design
All logical demands are converted to descriptions of system hardware and package ( Wikipedia. 2012 ) . “Logical information construction is converted into a physical architecture in footings of database structures” ( Wikipedia. 2012 ) .
Dynamic Systems Development Method ( DSDM )
DSDM is an nimble development method that is based on Rapid Application Development ( RAD ) . It uses an iterative and incremental attack to system development. Its chief ends are to suit changing demands and meet concern demands on clip and in budget.
DSDM execution includes 9 indispensable principals: active user engagement. sceptered users or squads. concentrate on frequent bringing. concern fittingness standard for recognized deliverables. iterative and incremental development. reversible alterations during development. demands base lined at high degree. integrated proving throughout the life rhythm and collaborative cooperation ( Wikipedia. 2012 ) .
Core techniques deployed in this methodological analysis are clip packaging. Moscow regulations and prototyping ( Wikipedia. 2012 ) . Time pugilism is a technique where clip intervals are allocated for certain undertakings to be completed. This helps to do certain that the undertaking stays on mark.
Figure 1: DSDM Development Process ( AGILE Methods of Software Development. 2011 )
There are five stages to this undertaking construction as shown in Figure 1:
Feasibility Study and Business Study
Suitability of DSDM is assessed in the feasibleness survey. The terminal merchandise is a “feasibility study. a feasibleness paradigm. and a planetary lineation program which includes a development program and a hazard log” ( Wikipedia. 2012 ) . In the concern survey phase. “a prioritized demands list. a concern country distribution. a system architecture definition. and an lineation prototyping program are developed” ( Wikipedia. 2012 ) .
Functional Model Iteration
A functional theoretical account is developed harmonizing to the demands set in the concern survey. From that. a functional paradigm is developed and tested with an terminal user or a reappraisal papers ( Wikipedia. 2012 ) . This stage is done iteratively. At the terminal of this stage. a functional prototyping reappraisal papers is presented ( Wikipedia. 2012 ) .
Design and Build Iteration
An execution scheme is developed based on functional and non-functional demands every bit good as any available trial records from old loop proving ( Wikipedia ) . Then. a design paradigm is built and tested with terminal users. Like the former stage. this is done iteratively. At the terminal of this stage. a user certification and trial record are developed ( Wikipedia. 2012 ) .
This stage includes acquiring stop user blessing and developing execution guidelines. stop user preparation. presenting the system to stop users and reexamining the impact of the enforced system on the concern ( Wikipedia. 2012 ) . The reappraisal is documented in a undertaking reappraisal papers ( Wikipedia. 2012 ) .
Normative Information Model-based Systems Analysis and Design ( NIMSAD )
NIMSAD is a meta-framework for measuring methodological analysiss. “Methodology is an expressed manner of apologizing thought and action through critical and originative thinking” ( Jayaratna. 1994. p. eleven ) . NIMSAD evaluates methodological analysiss via four elements ; the methodological analysis context. the methodological analysis user. the methodological analysis. and rating of the manner the methodological analysis evaluates the other three elements ( Koskinen. Lintinen. Sivula and Tilus. 2003 )
Table 2: NIMSAD Framework ( Koskinen. Lintinen. Sivula and Tilus. 2003 ) NIMSAD elements as represented in ( Forsell et al. . 1999 ) | Questions| Methodology Context|
Use situationStart for methodological analysis useCustomers and job ownersContext descriptionCulture and political relations of methodological analysis useRisks in depicting contextRisks of methodology| What sort of state of affairss does the methodological analysis suit? Which incidents initiate the usage of the methodological analysis? Who are the clients and job proprietors? How is the context described? What is the civilization and political relations of methodological analysis usage? What risks does the methodological analysis identify when depicting context? What are the hazards in utilizing the methodological analysis? | Methodology User|
Users motivations and valuesNeeded abstract reasoningNeeded skills| What are the users’ motivations and valuesWhat degree of abstract logical thinking is required from the user of the methodological analysis? What skills does the user of the methodological analysis demand to carry through undertakings required in methodological analysis usage? | Methodology|
Problem state of affairs and boundariesDiagnosis of situationPrognoses for systemProblem definingDeriving fanciful systemsDesign ( originally: logical and physical design separated ) Implementing the design| How does the methodological analysis aid in understanding the peculiar state of affairs and boundary scene? How does the methodological analysis user name what sort of system is needed? How the methodological analysis user makes a forecast for the system to be built? How the methodological analysis user defines jobs that need to be solved? How you get systems that need to be described? Is this stage done? How the methodological analysis user implements this stage? Is this stage described? What is included in it? | Evaluation|
Evaluation ( originally: instances before/during/after intercession separated ) | How are the other elements ( presented by NIMSAD ) evaluated? |
Methodology context describes suited state of affairss where the methodological analysis will be used and what is of import in those state of affairss ( Koskinen. Lintinen. Sivula and Tilus. 2003 ) . The methodological analysis user is usually the job convergent thinker or determination shaper. The methodological analysis describes how it supports the job work outing procedure. Last. rating evaluates “how the methodological analysis supports the problem-solving procedure. that is: job preparation. possible design of the solution. and existent job solving” ( Koskinen. Lintinen. Sivula and Tilus. 2003 ) .
SSADM is suited for big undertakings that have resources in footings of clip and money. It is besides suited where demands are more stable and do non alter so much during an on-going undertaking. It may non be suited for smaller undertakings as it is dearly-won and requires a batch of clip for execution and certification. Typically. this methodological analysis is applied in authorities sectors.
This methodological analysis is suited for undertakings that require faster. more flexible and lower cost development of information system. It is suited for undertakings which demands might alter ongoing development of the system.
Start of Methodology Use
The start of this methodological analysis is a feasibleness survey. It analyses whether a undertaking is technically possible. financially low-cost. compatible with the business’s patterns and socially acceptable in the company’s concern environment ( Wikipedia. 2012 ) . The consequence of the survey is a feasibleness survey papers ( Wikipedia. 2012 ) .
Like SSADM. the start of this methodological analysis is a feasibleness survey where hazards. undertaking demands and understanding and suitableness of the method to the undertaking are addressed. However. this method besides includes a concern survey.
Customers and Problem Owners
The clients and job proprietors in SSADM are normally the undertaking directors. information systems director. package providers. stakeholders. etc. However. SSADM does non take into history the mental concepts of users i. e. it does non see what views each user has on a job ( Sven ) .
All stakeholders are identified in the concern survey. The concern survey besides describes stakeholder engagement and precedence of undertakings ( UK Essays. 2011 ) . Normally. the client and job proprietors are the undertaking director. information systems director. system analyst and other users who are given decision-making rights.
Problem context is usually described utilizing informations flow diagrams and entity relational diagrams. SSADM provides utile tools to project directors and users. These tools such as the 1s mentioned before provide description of benefits and cost visibleness to Business and IT direction every bit good as users ( HKSAR. 2012 ) .
An initial job description may be presented in the feasibleness survey. However. more specific jobs are usually caught and resolved via prototyping where user feedback is indispensable in doing certain that the system satisfies all user demands.
Culture and Politicss of Methodology Use
The organisational context has high precedence ( Sven ) . It is bureaucratic in nature. hence this methodological analysis is good for an organisation with a hierarchal civilization. “The parts of organisational civilization that SSADM has consequence are control. way. hazard tolerance and communicating patterns” ( Schumacher. 2001-02 ) . DSDM
This method is less bureaucratic and suited for dynamic development. It is more adaptable where users are empowered i. e. users have determination devising privileges.
Hazards in Describing Context
Since SSADM chiefly uses informations flow diagrams to depict jobs. any irregular and unchanging forms are usually left out ( Sven ) . Besides. SSADM emphasizes on system analysis and certification that may take to “over- analyzing. which can be really clip and cost consuming ( Schumacher. 2001-02 ) .
Since this method takes a reiterative attack in paradigm development and acquiring user feedback. the development clip span may increase if users do non really cognize what they want. This may increase development costs and do the developed system to no longer be executable.
Hazards of Methodology
With big systems. there may be a danger of incurring high cost for systems analysis. Besides. since all informations flow diagrams have to be included. the resulted “outline diagram can go really unclear” ( Schumacher. 2001-02 ) . Furthermore. SSADM may be clip devouring i. e. each phase must be completed before the following. Since it is clip devouring. there is a danger that the terminal consequence “may non run into concern demands at the clip it is delivered” ( Schumacher. 2001-02 ) .
Hazards may increase when utilizing this methodological analysis when users/ squads are non empowered to do determinations. It becomes peculiarly hazardous and hard when users do non cognize what demands they want. Users must besides be actively involved in order for this method to work ( Wikipedia. 2012 ) . Changes that are irreversible may besides give an inauspicious consequence in this methodological analysis.
User Motives and Values
SSADM does non see the user’s mental concepts. Example. two different users may make two different informations flow diagrams for the same job. ( Sven )
This attack is to a great extent based on user feedback. Therefore. mental concepts of users are taken into consideration. Furthermore. users are expected to hold decision-making duties.
Needed Abstract Reasoning
SSADM is considered to be simple for its users.
The methodological analysis itself may besides be considered to be simple. However. users of this methodological analysis must hold proficient IT cognition in order for this method to work.
SSADM does non necessitate high-ranking accomplishments and may easy be taught. Users may besides be expected to hold cognition is utilizing instance tools and other mold and schematization tools that are used in this methodological analysis
Users or development squads are required to hold IT proficient accomplishments so that they are able to do timely determinations without holding to confer with direction. These accomplishments include cognition in utilizing IT development and direction tools.
Problem Situation and Boundaries
The system boundaries are defined through a logical design and expressed utilizing a context diagram. The context diagram besides shows the external entities that interact with the system and information flows between entities of the system. However. the “system boundaries building is test and mistake within SSADM” ( Sven )
This methodological analysis uses Moscow regulations to sort user demands into 4 ; must hold. should hold. could hold and desire to hold ( Wikipedia. 2012 ) . However. system boundaries may non be clearly defined in the beginning stages of this methodological analysis. Hence. specifying system boundaries may besides be test and mistake and becomes clearer as iterative prototyping takes topographic point.
Diagnosis of the Situation
Diagnosis is done via informations flow diagrams that provide a clear description of informations flows. It starts with a description of physical informations flow that is so extracted into a logical information theoretical account and a logical information flow theoretical account ( Sven ) . However. “only regular and frequent forms get modeled” ( Sven ) and alone events may non be described.
Diagnosis is done through test and mistake via an iterative cringle of paradigm development in the functional mold stage.
Prognosis of System
Prognosis of system may non be good defined in SSADM although Business System Options are developed and each proposed option is evaluated against deductions. benefits and costs ( Sven ) . It is assumed that clients know what they want therefore “the principle of clients desired provinces are unclear” ( Sven ) .
Prognosis is done ongoing system development and is besides non clear in earlier development stages. Prototyping allows users to rapidly place or alter demands during system development. Therefore. the developed system is more likely to run into user demands.
The job is defined in the feasibleness survey. However. the job at this phase remains obscure ( Sven ) . Specifying jobs may go clearer in the demands specification stage.
Problem is mistily defined in feasibleness survey and concern survey. Problem is farther defined and rapidly resolved throughout the DSDM development procedure.
Deducing Fanciful Systems
Requirements are formalized through informations flow diagrams where maps. procedures and user interfaces are defined. A specification paradigm may besides be developed presuming that the client knows what they want ( Sven ) .
The system is derived from functional theoretical account loop and design and physique. The results are paradigms that first implements critical maps to place jobs at an early phase of the undertaking. These paradigms may be of a concern paradigm. serviceability paradigm. public presentation paradigm and ( or ) capableness paradigm ( AGILE Methods of Software Development. 2011 )
Design is broken down into logical design and physical design. The logical design is created with informations flow diagrams and modifying a logical diagnosing diagram harmonizing to demands and feasibleness survey ( Sven ) .
SSADM provides generic guidelines for physical design of the system. Design determinations are based on proficient issues specific to a chosen environment that is chosen in the Technical System Option stage ( Sven ) .
Design is described in a design and build stage. Here. the non-functional demands are besides addressed. A design paradigm is identified and developed iteratively. acquiring user feedback every clip. The design paradigm is tested against the functional and non-functional demands ( UK Essays. 2011 )
Execution is non described in SSADM
Execution is described in an execution stage. The system is tested for user blessing and guidelines. After which. users of the system are trained so the system is implemented for terminal users. Finally. concern facets of the system are reviewed ( Wikipedia. 2012 ) .
Evaluation is besides non described in SSADM
Evaluation and testing is done continuously throughout the undertaking. Project viability is evaluated based on concern aims ( Wikipedia. 2012 ) . After the DSDM development life rhythm. there is a post-project stage that consists of system care. holes and sweetening. This stage is carried out harmonizing to DSDM rules.
More on NIMSAD…
NIMSAD points out that effectual job work outing depends on the method being used. the state of affairs the method is applied to and the user of the method ( Bielkowicz. Patel. Than Tun. 2002 ) . The rating of the method is “treated as a dynamic activity that is carried out before. during and after the application of the method” ( Bielkowicz. Patel. Than Tun. 2002 ) .
The model assumes that a method is a problem-solving procedure. Methodology user is separated from the methodological analysis context therefore is assumes that the job description is taken from an external position i. e. the methodological analysis user is non in the job. “It does non specify what constitutes a method and how to compare elements of a method” ( Bielkowicz. Patel. Than Tun. 2002 ) . Hence. the “framework may non be suited for proficient and theoretical rating of all types of methods e. g. Component-based Development methods” ( Bielkowicz. Patel. Than Tun. 2002 ) .
SSADM is more suited for organisations that are bureaucratic. structured and have resources to maintain up to be and clip that the methodological analysis nowadayss. DSDM is more suited for organisations that empower the methodological analysis users. where the development environment is dynamic and the undertaking requires faster development clip and lower costs.
NIMSAD provides a mechanism for a structured and critical rating of a method. It takes on a “problem based” rating attack and helps to critically analyze the construction. signifiers and stairss of a methodological analysis. However. this model may non work for all sorts of methods.
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