Estimation of web application development effort based on a conceptual model

Današnji razvoj društva i informacijskih sustava nameće potrebu za razvojem web aplikacija u što kraćem vremenskom periodu u skladu s postavljenim zahtjevima u pogledu efikasnije iskorištenosti sustava. Voditelji projekata su prilikom planiranja web projekata većinom usmjereni na vremensku varijablu. Razvoj web aplikacija na osnovi konceptualnog modela pruža bolju procjenu težine razvoja i umanjuje mogućnost pojave grešaka u razvoju. Do danas, predložen je značajan broj metoda za razvoj web aplikacija na osnovi konceptualnog modela, ali samo nekolicina od njih omogućava provođenje procesa procjene težine razvoja web aplikacija. Većina predloženih metoda koristi prethodno definirane težinske faktore na osnovu kojih vrše procjenu za novi model i izračun težine razvoja, što zahtijeva velike količine podataka o prethodnim projektima. U posljednje vrijeme u području procjene težine razvoja softverskih projekata, sve više pažnje se posvećuje izračunu funkcionalne veličine projekata, jer: (1) su bazirani na funkcionalnosti koja će biti isporučena krajnjem korisniku, a ne na artefaktima koji su nastali kao produkt završene aplikacije (na primjer broj web stranica, multimedijalnih datoteka itd.); (2) funkcionalnosti aplikacije mogu biti mjerene u ranoj fazi procesa razvoja web aplikacije; (3) su bazirani na standardima koji definiraju koncept veličine i zahtjeva za potrebe procjene veličine aplikacija; i (4) imaju široku prihvaćenost u industriji. Postoji nekoliko metoda za izračun funkcionalne veličine softvera koje su standardizirane, ali metoda koja je u posljednje vrijeme doživjela ogromnu prihvaćenost od strane istraživača i razvojnih inženjera je metoda COSMIC (Common Software Measurement International Consortium). Njena česta zastupljenost se može objasniti time da je vrlo jednostavna za korištenje i implementaciju, kao i vrlo jednostavna za učenje. Kombiniranih pristupa za procjenu težine razvoja web aplikacija, na bazi konceptualnih modela i funkcionalne veličine je jako malo u literaturi. Disertacijom je definirana procedura za kreiranje konceptualnih modela kao i metoda za izračun funkcionalne veličine web aplikacija na osnovi konceptualnih modela u svrhu kreiranja modela za izračun težine razvoja web aplikacija. Kao rezultat istraživanja u okviru ove disertacije nastao je matematički model pomoću kojeg je moguće na osnovi konceptualnog modela koristeći izračunatu funkcionalnu veličinu web aplikacije procijeniti težinu razvoja same web aplikacije izraženu u formi vremenske varijable. Također, u okviru disertacije razvijen je i sustav za automatsku procjenu težine razvoja web aplikacija, a koji podatke potrebne za izračun modela aktivno preuzima iz podatkovnog repozitorija prethodno razvijenih web aplikacija po predloženom modelu. Sustav je nazvan WADEES (Web Application Effort Estimation System) i omogućava da se na bazi konceptualnog modela izvrši automatski izračun CFP-a (engl. COSMIC Function Point, CFP) i procjeni napor za razvoj neke nove web aplikacije. Verifikacija modela za procjenu težine razvoja web aplikacija je provedena na osnovu predloženog modela i baze podataka razvijenih web aplikacija. Kao rezultat verifikacije istraživanja nastao je prototip sustava za procjenu težine razvoja web aplikacija razvijenih na osnovi konceptualnog modela.Development of society and information systems nowadays imposes the need for developing web applications in a short period of time in accordance with the set requirements concerning efficient utilization of the system. During web project planning, project managers are primarily focused on the time variable. Development of web applications on the basis of the conceptual model provides a better estimation of development effort and reduces possible occurrence of errors in development phase. So far, a number of methods for web application development on the basis of the conceptual model have been proposed, but only few of them implement effort estimation process for web applications. Most of the proposed methods have some drawbacks in that they require a large database of completed projects in order to perform new model assessment since they use predefined weighting factors to calculate development effort estimation. In recent years, the focus of the attention in the field of software development effort estimation has shifted to calculating the functional size of the projects, since they: (1) are based on the functionality that will be delivered to the end user and not on the artifacts created as a product of finished applications (eg. number of web pages, multimedia files, etc.); (2) can be measured in the early phases of development of web applications; (3) are based on standards that define the concept of the size and requirements for the purposes of assessing the size of the application; (4) are widely applicable in the industry. There are several standardized methods of calculating the functional size of the software, but the method that has recently experienced tremendous acceptance by researchers and development engineers is the COSMIC (Common Software Measurement International Consortium) method. The appeal of the COSMIC method can be contributed to the fact that it is very simple to use and implement, and very easy to learn. Combined approaches to estimate web application development effort on the basis of the conceptual models and functional size are rather hard to find in literature. The thesis defines a procedure to create conceptual models and methods of calculating functional size of web applications on the basis of conceptual models for the purposes of designing a model for calculation of web application development effort. The research resulted in a mathematical model, based on a conceptual model, which uses the calculated functional size of a web application to estimate the level of web application development effort represented as a time variable. In addition, within the thesis, a system for automatic web application development effort estimation was developed. The system actively collects the data necessary for model calculation from a data repository of the previously developed web applications by the proposed model. The system is called WADEES (Web Application Effort Estimation System) and it enables automatic calculation of the CFP (COSMIC Function Point) based on conceptual model and estimation of a new web application development effort. Verification of the model for development effort estimation for web applications is carried out on the basis of the proposed model and a database of previously developed web applications. As a result of the verification of the research, a prototype system to estimate development effort of web applications established on the basis of the conceptual model was created