Software Engineering

Outline of this presentationConstructive Cost Modeling (Constructive Cost Model)3 COCOMO Models http://en.wikipedia.org/wiki/COCOMOProject CharacteristicsSome AssumptionsBasic COCOMO ModelEquationsWhen Should You Use ItLimitationsExamples*

MATAKULIAH KODE - SKS

Constructive Cost ModelingCOCOMO is one of the most widely used software estimation models in the worldIt was developed by Barry Boehm in 1981COCOMO 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 ModelingCOCOMO has three different models that reflect the complexity: the Basic Model the Intermediate Model and the Detailed Model

*3 COCOMO Models :


Constructive Cost ModelingOrganic ModeSmall to medium size product developmentdeveloped in a familiar, in-house & stable environment,similar to the previously developed projectsrelatively small and requires little innovation*Project Characteristics


Constructive Cost ModelingSemidetached ModeTeam 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 ModelingEmbedded Modetight, inflexible constraints and interface requirements The product requires great innovationProduct 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 ModelingPrimary 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 customerAssumes the requirements specification is not substantially changed after the plans and requirements phase *Some Assumptions


Constructive Cost Modeling

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*Basic COCOMO Model: Equations


Constructive Cost ModelingBasic COCOMO is good for quick, early, rough order of magnitude estimates of software costs *When Should You Use It


Constructive Cost ModelingIts accuracy is necessarily limited because of its lack of factors which have a significant influence on software costsThe 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 ModelingWe have determined our project fits the characteristics of Semi-Detached modeWe estimate our project will have 32,000 Delivered Source Instructions. Using the formulas, we can estimate:*An Example


Constructive Cost ModelingEffort = 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*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 diselesaikanTDEV = 2.5 (91) 0.38= 14 bulanAn Example


Constructive Cost Modeling*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 diselesaikanTDEV = 2.5 (1216) 0.32 = 24 bulanAn Example


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Terimakasih..Untuk mahasiswa/i yang tidak ngantuk dan tetap konsentrasi Mengikuti Perkuliahan.Sampai berjumpa minggu depan .. (Dalam perkuliahan dan dosen yang sama)


Effort in man-months A COCOMO man-month consists of 152 hours of working time

KDSI is the Thousand Delivered Source Instructions

TDEV is the number of months estimated for software developmentFSP = Full-time equivalent Software Personnel, a measure of the equivalent number of people working on the project at a given time.

FSP = Full-time equivalent Software Personnel, a measure of the equivalent number of people working on the project at a given time.



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