LiGuo Huang

Value-based software engineering: a case study

The information technology fields accelerating rate of change makes feedback control essential for organizations to sense, evaluate, and adapt to changing value propositions in their competitive marketplace. Although traditional project feedback control mechanisms can manage the development efficiency of stable projects in well-established value situations, they do little to address the projects actual value, and can lead to wasteful misuse of an organizations scarce resources. The value-based approach to software development integrates value considerations into current and emerging software engineering principles and practices, while developing an overall framework in which these techniques compatibly reinforce each other.

How Much Software Quality Investment Is Enough: A Value-Based Approach

This article draws on results from the emerging field of value-based software engineering (VBSE). VBSE aims to provide a quantitative approach to questions as how much software quality investment is enough. Based on the COCOMO II cost-estimation model and the COQUALMO quality-estimation model, quantitative risk analysis helps determine when to stop testing software and release the product. Further, we show how the model and approach can assess the relative payoff of value-based testing as compared to value-neutral testing

The ROI of software dependability: The iDAVE model

In most organizations, proposed investments in software dependability compete for limited resources with proposed investments in software and system functionality, response time, adaptability, speed of development, ease of use, and other system capabilities. The lack of good return-on-investment models for software dependability makes determining the overall business case for dependability investments difficult. So, with a weak business case, investments in software dependability and the resulting system dependability are frequently inadequate. Dependability models will need to support stakeholders in determining their desired levels for each dependability attribute and estimating the cost, value, and ROI for achieving those. At the University of Southern California, researchers have developed software cost- and quality-estimation models and value-based software engineering processes, methods, and tools. We used these models and the value-based approach to develop an Information Dependability Attribute Value Estimation model (iDAVE) for reasoning about software dependabilitys ROI.

Using empirical testbeds to accelerate technology maturity and transition: the SCRover experience

This paper is an experience report on a first attempt to develop and apply a new form of software: a full-service empirical testbed designed to evaluate alternative software dependability technologies, and to accelerate their maturation and transition into project use. The SCRover testbed includes not only the specifications, code, and hardware of a public safety robot, but also the package of instrumentation, scenario drivers, seeded defects, experimentation guidelines, and comparative effort and defect data needed to facilitate technology evaluation experiments. The SCRover testbeds initial operational capability has been recently applied to empirically evaluate two architecture definition languages (ADLs) and toolsets, Mae and AcmeStudio. The testbed evaluation showed (1) that the ADL-based toolsets were complementary and cost-effective to apply to mission-critical systems; (2) that the testbed was cost-effective to use by researchers; and (3) that collaboration in testbed use by researchers and the Jet Propulsion Laboratory (JPL) project users resulted in actions to accelerate technology maturity and transition into project use. The evaluation also identified a number of lessons learned for improving the SCRover testbed, and for development and application of future technology evaluation testbeds.

Applying the Value/Petri process to ERP software development in China

Commercial organizations increasingly need software processes sensitive to business value, quick to apply, and capable of early analysis for subprocess consistency and compatibility. This paper presents experience in applying a lightweight synthesis of a Value-Based Software Quality Achievement (VBSQA) process and an Object-Petri-Net-based process model (called VBSQA-OPN) to achieve a manager-satisfactory process for software quality achievement in an on-going ERP software project in China. The results confirmed that 1) the application of value-based approaches was inherently better than value-neutral approaches adopted by most ERP software projects; 2) the VBSQA-OPN model provided project managers with a synchronization and stabilization framework for process activities, success-critical stakeholders and their value propositions; 3) process visualization and simulation tools significantly increased management visibility and controllability for the success of software project.

A value-based process for achieving software dependability

Since different systems have different success-critical stakeholders, and these stakeholders depend on the system in different ways, using traditional one-size-fits-all dependability metrics to drive the system and software development process is likely to lead to delivered systems that are unsatisfactory to some stakeholders. This paper proposes a Value-Based Software Dependability Achievement (VBSDA) process generated from the WinWin Spiral Model’s risk-driven approach coupled with a set of value-based dependability analysis frameworks, methods, and models for reasoning about software and system dependability. It helps project success-critical stakeholders define, negotiate and develop mission-specific combinations of dependability attributes. The NASA/USC Inspector SCRover (ISCR) project is used as a case study to elaborate the process.

Tailor the value-based software quality achievement process to project business cases

This paper proposes a risk-based process strategy decision-making approach. To improve the flexibility in applying the Value-Based Software Quality Achievement (VBSQA) process framework, we embed the risk-based process strategy decision-making approach into the VBSQA process framework. It facilitates project managers to tailor the VBSQA process framework to different project business cases (schedule-driven, product-driven, and market trend-driven). A real world ERP (Enterprise Resource Planning) software project (DIMS) in China is used as an example to illustrate different process strategies generated from process tailoring.

Strategic architectural flexibility

Most projects commit to a set of required features and (at best) a most-likely budget and schedule for developing them. This means that, even before the changes start coming, there is roughly a 50% chance that the most-likely budget and schedule are insufficient, and the project is headed for an overrun. Planning for change in a development project is essential. But how much should be invested in architectural flexibility to accommodate this? Too little will incur a high risk of costly late changes and architecture breakage; too much may not leave enough time to implement a sufficient set of critical capabilities. We have been using and refining a model based approach to assist in determining an appropriate degree of architectural flexibility by introducing a modularity factor for the software architecture based on the core capabilities and a set of anticipated changes. This experience has helped us identify the critical success factors for strategically applying architectural flexibility within tight constraints such as cost, quality, or a fixed schedule. We elaborate the critical success factors, present a case study of their application, and their relation to recent research results in such areas as strategic design.

SAIV/CAIV/SCQAIV tutorial

The following topics are dealt with: Strategic software engineering; strategic schedule planning (SAIV); full-text title database case-study; CAIV/SCQAIV, MBASE; USC experience and results and MBASE model integration.

Determining relevant training data for effort estimation using Window-based COCOMO calibration

Abstract Context A software estimation model is often built using historical project data. As software development practices change over time, however, a model based on past data may not make accurate predictions for a new project. Objectives We investigate the use of moving windows to determine relevant training data for COCOMO calibration. Method We present a windowing calibration approach to calibrating COCOMO and assess performance of effort estimation models calibrated using windows and all data. Results Our results show that calibrating COCOMO using small windows of the most recently completed projects generates superior estimates than using all available historical projects. Large windows tend to produce worse estimates. Conclusions This study provides empirical evidence to support the use of small windows of projects completed so far to calibrate models when COCOMO-like data is available. Additionally, when the change in software development over time is rapid, the use of windows is more justifiable for improving estimation accuracy.