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2 Bagian 9 FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 92

3 Outline of this presentation  Constructive Cost Modeling  3 COCOMO Models  Project Characteristics  Some Assumptions  Basic COCOMO Model  Equations  When Should You Use It  Limitations  Examples FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

4  COCOMO is one of the most widely used software estimation models in the world  It was developed by Barry Boehm in 1981  COCOMO predicts the effort and schedule for a software product development based on inputs relating to the size of the software and a number of cost drivers that affect productivity Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

5  COCOMO has three different models that reflect the complexity:  the Basic Model  the Intermediate Model  and the Detailed Model Constructive Cost Modeling 3 COCOMO Models FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

6  Organic Mode  Small to medium size product development  developed in a familiar, in-house & stable environment,  similar to the previously developed projects  relatively small and requires little innovation Constructive Cost Modeling Project Characteristics FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

7  Semidetached Mode  Team members have an intermediate level of experience with related systems.  Perhaps a mixture of experienced and inexperienced people.  Parts of the project may require rigorous interfaces. Project Characteristics Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

8  Embedded Mode  tight, inflexible constraints and interface requirements  The product requires great innovation  Product must operate within a strongly coupled complex of H/W, S/W, regulations, and operational procedures.  Tighter requirements and more inflexible scheduling Project Characteristics Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

9  Primary cost driver is the number of Delivered Source Instructions (DSI) developed by the project (LOC/KLOC)  COCOMO estimates assume that the project will enjoy good management by both the developer and the customer  Assumes the requirements specification is not substantially changed after the plans and requirements phase Some Assumptions Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

10  Basic COCOMO model estimates the software development effort using only a single predictor variable (size in DSI) and three software development modes Basic COCOMO Model Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

11 ModeEffortSchedule OrganicE=2.4*(KDSI) 1.05 TDEV=2.5*(E) 0.38 SemidetachedE=3.0*(KDSI) 1.12 TDEV=2.5*(E) 0.35 EmbeddedE=3.6*(KDSI) 1.20 TDEV=2.5*(E) 0.32 Man-Month / Person-MonthMonth Basic COCOMO Model: Equations Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

12  Basic COCOMO is good for quick, early, rough order of magnitude estimates of software costs When Should You Use It Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

13  Its accuracy is necessarily limited because of its lack of factors which have a significant influence on software costs  The Basic COCOMO estimates are within a factor of 1.3 only 29% of the time, and within a factor of 2 only 60% of the time Limitation of Basic COCOMO Model Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

14  We have determined our project fits the characteristics of Semi-Detached mode  We estimate our project will have 32,000 Delivered Source Instructions. Using the formulas, we can estimate: An Example Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

15  Effort = 3.0*(32) 1.12 = 146 Man-Months  Schedule = 2.5*(146) 0.35 = 14 Months  Productivity / Man Month= 32,000 DSI / 146 MM = 219 DSI/MM  Average Staffing / Month= 146 MM /14 M = 10 Man An Example Constructive Cost Modeling FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

16 Bila sebuah proyek dikelompokkan kedalam organic mode project diperkirakan akan menghasilkan 32,000 DSI, maka: PM = 2.4 * (32) 1.05 = 91 p.m. Dari nilai PM yang diperoleh dapat dihitung berapa lama proyek akan diselesaikan TDEV = 2.5 (91) 0.38 = 14 bulan Constructive Cost Modeling An Example FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

17 Bila sebuah proyek dikelompokkan kedalam embedded mode project diperkirakan akan menghasilkan 128,000 DSI, maka: PM = 3.6 (128) 1.20 = 1216 p.m. Dari nilai PM yang diperoleh dapat dihitung berapa lama proyek akan diselesaikan TDEV = 2.5 (1216) 0.32 = 24 bulan Constructive Cost Modeling An Example FAKULTAS TEKNOLOGI INFORMASIREKAYASA PERANGKAT LUNAK – KP146 – 3 SKS – BAG 9

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