Spiral Model free essay sample

The spiral model combines the idea of iterative development (prototyping) with the systematic, controlled aspects of the waterfall model. It allows for incremental releases of the product, or incremental refinement through each time around the spiral. The spiral model also explicitly includes risk management within software development. Identifying major risks, both technical and managerial, and determining how to lessen the risk helps keep the software development process under control.The spiral model is based on continuous refinement of key products for requirements definition and analysis, system and software design, and implementation (the code). At each iteration around the cycle, the products are extensions of an earlier product. This model uses many of the same phases as the waterfall model, in essentially the same order, separated by planning, risk assessment, and the building of prototypes and simulations. Documents are produced when they are required, and the content reflects the information necessary at that point in the process. We will write a custom essay sample on Spiral Model or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page All documents will not be created at the beginning of the process, nor all at the end (hopefully). Like the product they define, the documents are works in progress. The idea is to have a continuous stream of products produced and available for user review. The spiral lifecycle model allows for elements of the product to be added in when they become available or known. This assures that there is no conflict with previous requirements and design. This method is consistent with approaches that have multiple software builds and releases and allows for making an orderly transition to a maintenance activity.Another positive aspect is that the spiral model forces early user involvement in the system development effort. For projects with heavy user interfacing, such as user application programs or instrument interface applications, such involvement is helpful. Starting at the center, each turn around the spiral goes through several task regions. ?Determine the objectives, alternatives, and constraints on the new iteration. ?Evaluate alternatives and identify and resolve risk issues. ?Develop and verify the product for this iteration. ?Plan the next iteration.Note that the requirements activity takes place in multiple sections and in multiple iterations, just as planning and risk analysis occur in multiple places. Final design, implementation, integration, and test occur in iteration 4. The spiral can be repeated multiple times for multiple builds. Using this method of development, some functionality can be delivered to the user faster than the waterfall method. The spiral method also helps manage risk and uncertainty by allowing multiple decision points and by explicitly admitting that all of anything cannot be known before the subsequent activity starts.WATERFALLS CYCLE The waterfall model is a sequential design process, often used in software development processes, in which progress is seen as flowing steadily downwards (like a waterfall) through the phases of Conception, Initiation, Analysis, Design, Construction, Testing,Production/Implementation and Maintenance. The unmodified waterfall model. Progress flows from the top to the bottom, like a waterfall. The waterfall development model originates in the manufacturing andconstruction industries: highly structured physical environments in which after-the-fact changes are prohibitively costly, if not impossible.Since no formal software development methodologies existed at the time, this hardware-oriented model was simply adapted for software development. The first known presentation describing use of similar phases in software engineering was held by Herbert D. Benington at Symposium on advanced programming methods for digital computers on 29 June 1956. This presentation was about the development of software for SAGE. In 1983 the paper was republished with a foreword by Benington pointing out that the process was not in fact performed in strict top-down, but depended on a prototype.The first formal description of the waterfall model is often cited as a 1970 article by Winston W. Royce, though Royce did not use the term waterfall in this article. Royce presented this model as an example of a flawed, non-working model (Royce 1970). This, in fact, is how the term is generally used in writing about software development—to describe a critical view of a commonly used software practice. In Royces original waterfall model, the following phases are followed in order: 1. Requirements specification 2. Design 3. Construction (AKA implementation or coding) 4. Integration 5. Testing and debugging (AKA Validation) 6. Installation 7. Maintenance SDLC Systems Development Life Cycle (SDLC) is a process used by a systems analyst to develop an information system, including requirements,validation, training, and user (stakeholder) ownership. Any SDLC should result in a high quality system that meets or exceeds customer expectations, reaches completion within time and cost estimates, works effectively and efficiently in the current and planned Information Technology infrastructure, and is inexpensive to maintain and cost-effective to enhance.Computer systems are complex and often (especially with the recent rise of Service-Oriented Architecture) link multiple traditional systems potentially supplied by different software vendors. To manage this level of complexity, a number of SDLC models or methodologies have been created, such as waterfall; spiral; Agile software development; rapid prototyping; incremental; and synchronize and stabilize. SDLC models can be described along a spectrum of agile to iterative to sequential. Agile methodologies, such as XP and Scrum, focus on lightweight processes which allow for rapid changes along the development cycle.

Identifying Post-Marital Residence Archaeologically

Identifying Post-Marital Residence Archaeologically A significant piece of kinship studies in anthropology and archaeology both is post-marital residence patterns, the rules within a society that determine where a child of a group resides after they get married. In pre-industrial communities, people generally live(d) in family compounds. Residence rules are essential organizing principles for a group, allowing families to build a labor force, share resources, and plan out rules for exogamy (who can marry who) and inheritance (how the shared resources are split among the survivors). Identifying Post-Marital Residence Archaeologically Beginning in the 1960s, archaeologists began attempting to identify patterns which might suggest post-marital residence at archaeological sites. The first attempts, pioneered by James Deetz, William Longacre and James Hill among others, were with ceramics, particularly decoration and style of pottery. In a patrilocal residence situation, the theory went, female pottery makers would bring in styles from their home clans and the resulting artifact assemblages would reflect that. That didnt work very well, in part because contexts where potsherds are found (middens) are rarely clear cut enough to indicate where the household was and who was responsible for the pot. See Dumond 1977 for a (fairly dyspeptic and so fairly typical for its era) discussion. DNA, isotope studies, and biological affinities have also been used with some success: the theory is that these physical differences would clearly identify the people who are outsiders to the community. The problem with that class of investigation is it is not always clear that where people are buried necessarily reflects where people lived. Examples of the methodologies are found in Bolnick and Smith (for DNA), Harle (for affinities) and Kusaka and colleagues (for isotope analyses). What seems to be a fruitful methodology of identifying post-marital residence patterns is using community and settlement patterns, as described by Ensor (2013). Post-Marital Residence and Settlement In his 2013 book The Archaeology of Kinship, Ensor lays out the physical expectations for settlement patterning in different post-marital residence behaviors. When recognized in the archaeological record, these on-the-ground, datable patterns provide insight into the societal makeup of the residents. Since archaeological sites are by definition diachronic resources (that is, they span decades or centuries and so contain evidence of change over time), they can also illuminate how residence patterns change as the community expands or contracts. There are three main forms of PMR: neolocal, unilocal and multi-local residences. Neolocal can be considered the pioneer stage, when a group consisting of parent(s) and child(ren) move away from existing family compounds to start new. Architecture associated with such a family structure is an isolated conjugal house which is not aggregated or formally situated with other dwellings. According to cross-cultural ethnographic studies, conjugal houses typically measure less that 43 square meters (462 square feet) in floor plan. Unilocal Residence Patterns Patrilocal residence is when the boys of the family stay in the family compound when they marry, bringing in spouses from elsewhere. Resources are owned by the men of the family, and, although the spouses reside with the family, they are still part of the clans where they were born. Ethnographic studies suggest that in these cases, new conjugal residences (whether rooms or houses) are constructed for the new families, and eventually a plaza is required for meeting places. A patrilocal residence pattern thus includes a number of conjugal residences scattered around a central plaza. Matrilocal residence is when the girls of the family stay in the family compound when they marry, bringing in spouses from elsewhere. Resources are owned by the women of the family and, although the spouses can reside with the family, they are still part of the clans where they were born. In this type of residence pattern, according to cross-cultural ethnographic studies, typically sisters or related women and their families live together, sharing domiciles which average 80 sq m (861 sq ft) or more. Meeting palces such as plazas are not necessary, because the families reside together. Cognatic Groups Ambilocal residence is a unilocal residence pattern when each couple decides which family clan to join. Bilocal residence patterns is a multi-local pattern in which each partner stays in their own family residence. Both of these have the same complex structure: both have plazas and small conjugal house groups and both have multifamily dwellings, so they cannot be distinguished archaeologically. Summary Residence rules define who is us: who can be relied on in emergencies, who is required to work on the farm, who we can marry, where we need to live and how our family decisions are made. Some argument can be made for residential rules driving the creation of ancestor worship and unequal status: who is us must have a founder (mythical or real) to identify, people who are related to a particular founder might be of a higher rank than others. By making the main sources of family income from outside of the family, the industrial revolution made post-marital residence no longer necessary or, in most cases today, even possible. Most likely, as with everything else in archaeology, post-marital residence patterns will be best identified using a variety of methods. Tracing the settlement pattern change of a community, and comparing physical data from cemeteries and changes in artifact styles from midden contexts will help approach the problem and clarify, as much as possible, this interesting and necessary societal organization. Sources Bolnick DA, and Smith DG. 2007. Migration and Social Structure among the Hopewell: Evidence from Ancient DNA. American Antiquity 72(4):627-644. Dumond DE. 1977. Science in Archaeology: The Saints Go Marching In. American Antiquity 42(3):330-349. Ensor BE. 2011. Kinship Theory in Archaeology: From Critiques to the Study of Transformations. American Antiquity 76(2):203-228. Ensor BE. 2013. The Archaeology of Kinship. Tucson: The University of Arizona Press. 306 p. Harle MS. 2010. Biological Affinities and the Construction of Cultural Identity for the Proposed Coosa Chiefdom. Knoxville: University of Tennessee. Hubbe M, Neves WA, Oliveira ECd, and Strauss A. 2009. Postmarital residence practice in southern Brazilian coastal groups: continuity and change.  Latin American Antiquity 20(2):267-278. Kusaka S, Nakano T, Morita W, and Nakatsukasa M. 2012. Strontium isotope analysis to reveal migration in relation to climate change and ritual tooth ablation of Jomon skeletal remains from western Japan. Journal of Anthropological Archaeology 31(4):551-563. Tomczak PD, and Powell JF. 2003. Postmarital Residence Patterns in the Windover Population: Sex-Based Dental Variation as an Indicator of Patrilocality. American Antiquity 68(1):93-108.

CLOUD COMPUTING Research Paper Example | Topics and Well Written Essays - 1750 words

CLOUD COMPUTING - Research Paper Example Mork et al. (2011:13) say that â€Å"cloud computing should be distributed and interactively accessible as it provides interoperability between the new and legacy technologies† Cloud computing is technollogy that utilizes the central remote servers and the internet to mantain applications and data. Cloud computing makes it possible for businesses and consumers to use aplications without the accesss and installation of their files using any computer that is connected to the internet. Therefore, it this technology permits for a more efficient computing by centralizing, data storage, and bandwidth. As the potential benefits of cloud computing are many, they are faced with numerous legal, proffesional, and ethical issues. The paper will discuss how cloud computing has impacted on the legal, social and proffesional spheres with regard to storage and transformation of data and inforrmation. The main objective of cloud computing has been to apply the high performance computimg power mostly used in research, health and military facilities to perform trillions of computations in a second, in consumer oriented apllications, and to deliver personalised information. This infrastructure of shared IT consists of a large pool of sytems that are interlinked. This creates legal and ethical isssues within the cloud (Buyya, Broberg, & Goscinski, 2010:23-26). Discussion As highlighted earlier, cloud computing is a type of technology that utilizes the internet and one remote server so as mantain data and different applications. This makes it a very young concept that is yet to be embraced by the global workforce. Cloud computing provides a cost effective IT resource as the cost on demand IT based on the actual customer’s usage. As a result of the rapid growth, numerous companies have been unable to handle their IT requirement even after having a data center that was inhouse. The usage of cloud services helps to enhance the IT capabilities without investing huge amount s in the new datacenters. As a consequence, this tpye of technology aids companies with an efficient way of computing by centralizing processing, memory, bandwidth, and storage. To show that cloud computing has began having mass appeal in the corporate data centers, it has enabled the data centers to operate on a similar internet through the process of enabling the computing process of computing resources to be shared and accessed as virtual resources in scalable and secure manner. Unlike showing proffesionalism, this virtualization is a compromise to security and ethical issues. Ethical issues are not separable with cloud computing. The major areas of concern are resource/stoarage virtualization, scalability and elasticity, usage optimization, ease of usage, fast information sharing delivery, and control, accessibility, and anonymity. The first ethical issue is privacy. The concern with regard to privacy is that the service providers of cloud have total control over the data and co mmunication stored between user and the host company (Racoma, 2012). This is attributed to the fact that service providers have complete over the data the are storing, and as a conseqence, they are responsible for a lot of private information and data. Once this is out of reach of the users, the fear is that it can be utilised for purposes the user doess not desire. As such, of late there have a push by the privacy advocates for a higher level of transparency from the