Jarir K. Chaar

Orthogonal defect classification-a concept for in-process measurements

Orthogonal defect classification (ODC), a concept that enables in-process feedback to software developers by extracting signatures on the development process from defects, is described. The ideas are evolved from an earlier finding that demonstrates the use of semantic information from defects to extract cause-effect relationships in the development process. This finding is leveraged to develop a systematic framework for building measurement and analysis methods. The authors define ODC and discuss the necessary and sufficient conditions required to provide feedback to a developer; illustrate the use of the defect type distribution to measure the progress of a product through a process; illustrate the use of the defect trigger distribution to evaluate the effectiveness and eventually the completeness of verification processes such as inspection or testing; provides sample results from pilot projects using ODC; and open the doors to a wide variety of analysis techniques for providing effective and fast feedback based on the concepts of ODC. >

In-process evaluation for software inspection and test

The goal of software inspection and test is to reduce the expected cost of software failure over the life of a product. The authors extend the use of defect triggers, the events that cause defects to be discovered, to help evaluate the effectiveness of inspections and test scenarios. In the case of inspections, the defect trigger is defined as a set of values that associate the skills of the inspector with the discovered defect. Similarly, for test scenarios, the defect trigger values embody the deferring strategies being used in creating these scenarios. The usefulness of triggers in evaluating the effectiveness of software inspections and tests is demonstrated by evaluating the inspection and test activities of some software products. These evaluations are used to point to deficiencies in inspection and test strategies, and to progress made in improving such strategies. The trigger distribution of the entire inspection or test series may then be used to highlight areas for further investigation, with the aim of improving the design, implementation, and test processes. >

A case study of software process improvement during development

We present a case study of the use of a software process improvement method which is based on the analysis of defect data. The first step of the method is the classification of software defects using attributes which relate defects to specific process activities. Such classification captures the semantics of the defects in a fashion which is useful for process correction. The second step utilizes a machine-assisted approach to data exploration which allows a project team to discover such knowledge from defect data as is useful for process correction. We show that such analysis of defect data can readily lead a project team to improve their process during development. >

In-process improvement through defect data interpretation

An approach that involves both automatic and human interpretation to correct the software production process during development is becoming important in IBM as a means to improve quality and productivity. A key step of the approach is the interpretation of defect data by the project team. This paper uses examples of such correction to evaluate and evolve the approach, and to inform and teach those who will use the approach in software development. The methodology is shown to benefit different kinds of projects beyond what can be achieved by current practices, and the collection of examples discussed represents the experiences of using a model of correction.

Developing manufacturing control software: a survey and critique

The complexity and diversity of manufacturing software and the need to adapt this software to the frequent changes in the production requirements necessitate the use of a systematic approach to developing this software. The software life-cycle model (Royce, 1970) that consists of specifying the requirements of a software system, designing, implementing, testing, and evolving this software can be followed when developing large portions of manufacturing software. However, the presence of hardware devices in these systems and the high costs of acquiring and operating hardware devices further complicate the manufacturing software development process and require that the functionality of this software be extended to incorporate simulation and prototyping.This paper reviews recent methods for planning, scheduling, simulating, and monitoring the operation of manufacturing systems. A synopsis of the approaches to designing and implementing the real-time control software of these systems is presented. It is concluded that current methodologies support, in a very restricted sense, these planning, scheduling, and monitoring activities, and that enhanced performance can be achieved via an integrated approach.

Essential requirements for a workflow standard

The OMG BODTF has issued an RFP for a workflow standard, and by the time this workshop is held, the initial responses to the RFP will be in. We outline a set of important requirements that can be used to evaluate the responses. We also analyze the current version of the dominant workflow standard from the Workflow Management Coalition, and examine it in the context of workflow execution across a heterogeneous, distributed infrastructure. The OMG BODTF needs to consider these issues while creating its own workflow standard.

Real-time software methodologies: are they suitable for developing manufacturing control software?

Computer-Integrated Manufacturing (CIM) systems may be classified as real-time systems. Hence, the applicability of methodologies that are developed for specifying, designing, implementing, testing, and evolving real-time software is investigated in this article.The paper highlights the activities of the software development process. Among these activities, a great emphasis is placed on automating the software requirements specification activity, and a set of formal models and languages for specifying these requirements is presented. Moreover, a synopsis of the real-time software methodologies that have been implemented by the academic and industrial communities is presented together with a critique of the strengths and weaknesses of these methodologies.The possible use of the real-time methodologies in developing the control software of efficient and dependable manufacturing systems is explored. In these systems, efficiency is achieved by increasing the level of concurrency of the operations of a plan, and by scheduling the execution of these operations with the intent of maximizing the utilization of the devices of their systems. On the other hand, dependability requires monitoring the operations of these systems. This monitoring activity facilitates the detection of faults that may occur when executing the scheduled operations of a plan, recovering from these faults, and, whenever feasible, resuming the original schedule of the system.The paper concludes that the set of surveyed methodologies may be used to develop the real-time control software of efficient and dependable manufacturing systems. However, an integrated approach to planning, scheduling, and monitoring the operations of these systems will significantly enhance their utility, and no such approach is supported by any of these methodologies.

A specification language for planning and fault recovery in manufacturing systems

This paper presents the syntax and semantics of a component-oriented rule-based language for specifying the formal models of manufacturing systems. A model captures the state of a component of the system in a set of first-order logic predicates, and it captures the semantics of the operations performed by this component in a set of rules that determine the preconditions and postconditions of an operation. The models are then used to plan the sequence of operations of each class of jobs to be manufactured by these systems. A plan-oriented fault detection and correction strategy is proposed. This strategy can automatically handle any combination of faults that may occur when monitoring the operations of manufacturing systems. A fault-tree is consulted prior to executing the scheduled operations of a plan, and the faults that affect the execution of these operations are handled subsequently. Resuming the original cyclic schedule is attempted, whenever feasible. As a proof of concept, a prototype implementation of both the main constructs of the component-oriented rule-based language and the planning and fault-recovery algorithms presented in this paper have been completed. This prototype is implemented on a Unix-based system in the Ada programming language. The specification of a manufacturing system is first expressed in the proposed language. These statements are then translated into Ada code. This code is next compiled by a Verdix Ada compiler and is executed in order to create and populate the model data structure of the system. A detailed plan of execution and a set of fault-recovery plans may then be derived for a job to be manufactured on this system.

An inference structure for process feedback: technique and implementation

AbstractThis paper presents an automatic technique for making simple inferences about the stages in a software production process, discusses implementation of the technique, and validates the technique using defect data from several software development projects. The technique represents an approach to automate process feedback that may be based on either experience and common sense or historical data. Specifically, we present(1)A software defect classification scheme that relates defects to process stages. As an example of such a scheme, we describe ‘orthogonal defect classification’, which associates types of defects with stages, such as high-level design, low-level design, code, and system test. These associations are summarized in a ‘principal association’ table, which serves as a model for the production process.(2)Rules that provide simple in-process feedback about a process stage based on the defects associated with that stage. We discuss how inferences can be made, with and without historical information for the process, and illustrate application of the inference technique to the software production process.(3)An implementation of the rules using a statistical programming language. Finally, we consider the technique in the software production context as a particular case of a general technique that makes use of both human judgment and historical data, and discuss extensions.

On the evaluation of software inspections and tests

The goal of software inspections and tests is to reduce the expected cost of software failure over the life of a product. This paper extends the use of defect triggers, the events which cause defects to be discovered, to help evaluate the effectiveness of inspection and test activities. In the case of inspections, the defect trigger is defined as a set of values which associate the skills of the inspector with the discovered defect. Similarly, for tests, the defect trigger values embody the various strategies being used in creating test scenarios. The usefulness of triggers in evaluating the effectiveness of software inspections and tests is demonstrated by evaluating the inspection and test activities of some software products. These evaluations are used to point to both deficiencies in inspection and test strategies, and progress made in improving such strategies.<<ETX>>