The Supportive Effect of Traceability Links in Change Impact Analysis for Evolving Architectures – Two Controlled Experiments

Timing analysis is used to extract the timing properties of a system. Various timing analysis techniques and tools have been developed over the past decades. However, changes in hardware platform and software architecture introduced new challenges in timing analysis techniques. In our research, we aim to develop a hybrid approach to provide safe and precise timing analysis results. In this approach, we will divide the original code into smaller code blocks, and then construct a timing model based on the information acquired by measuring the execution time of every individual block. This process can introduce changes in the software architecture. In this paper, we use a multi-component benchmark to investigate the impact of software architecture on the timing behaviour of a system.

Safety standards prescribe change impact analysis (CIA) during evolution of safety-critical software systems. Although CIA is a fundamental activity, there is a lack of empirical studies about how it is performed in practice. We present a case study on CIA in the context of an evolving automation system, based on 14 interviews in Sweden and India. Our analysis suggests that engineers on average spend 50–100 h on CIA per year, but the effort varies considerably with the phases of projects. Also, the respondents presented different connotations to CIA and perceived the importance of CIA differently. We report the most pressing CIA challenges, and several ideas on how to support future CIA. However, we show that measuring the effect of such improvement solutions is non-trivial, as CIA is intertwined with other development activities. While this paper only reports preliminary results, our work contributes empirical insights into practical CIA.

Software change impact analysis (CIA) methods enable developers to understand potential impacts of a code change so that the change can be executed confidently without affecting reliability of the software. However, existing CIA approaches do not support CIA for all source code granularities. Additionally, they lack support for inter-granular change impact queries and hidden dependencies. This paper introduces Augur, an automated static code analysis-based CIA approach that addresses these shortcomings. Augur infers and maintains semantic and environment dependencies along with data and control dependencies between source code entities across granularities. Additionally, Augur uses Change Impact Query Language, a novel query language for impact analysis proposed in this paper, to support inter-granular CIA queries with batch querying feature. Augur has been realized as a Visual Studio extension called Augur-Tool. We have conducted quantitative evaluation on two open-source and two industrial projects to assess the accuracy of the tool. Results from the evaluation indicate that Augur provides CIA with high accuracy (average precision 55% and average recall 85%).

Regulatory authorities of e.g. the automotive, avionic, or railway domain pose high requirements concerning safety assurance activities. One activity known from requirements engineering (RE) is requirements traceability. We propose a model-based methodology to facilitate trace link visualization over several levels of abstraction and different viewpoints. This intuitive visualization concept allows to see (i) the artifact importance using the degree and betweenness centrality measure, and (ii) the impact of an artifact change to other artifacts. Based on this, a novel impact analysis algorithm is proposed.

"Change Impact Analysis" is the process of determining the consequences of a modification to software. In theory, change impact analysis should be done during software maintenance, to make sure changes do not introduce new bugs. Many approaches and techniques are proposed to help programmers do change impact analysis automatically. However, it is still an open question whether and how programmers do change impact analysis. In this paper, we conducted two studies, one in-depth study and one breadth study. For the in-depth study, we recorded videos of nine professional programmers repairing two bugs for two hours. For the breadth study, we surveyed 35 professional programmers using an online system. We found that the programmers in our studies did static change impact analysis before they made changes by using IDE navigational functionalities, and they did dynamic change impact analysis after they made changes by running the programs. We also found that they did not use any change impact analysis tools.

Engineers working on safety critical software development must explicitly specify trace links as part of Impact Analyses (IA), both to code and non-code development artifacts. In large-scale projects, constituting information spaces of thousands of artifacts, conducting IA is tedious work relying on extensive system understanding. We propose to support this activity by enabling engineers to reuse knowledge from previously completed IAs. We do this by mining the trace links in documented IA reports, creating a semantic network of the resulting traceability, and rendering the resulting network amenable to visual analyses. We studied an Issue Management System (IMS), from within a company in the power and automation domain, containing 4,845 IA reports from 9 years of development relating to a single safety critical system. The domain has strict process requirements guiding the documented IAs. We used link mining to extract trace links, from these IA reports to development artifacts, and to determine their link semantics. We constructed a semantic network of the interrelated development artifacts, containing 6,104 non-code artifacts and 9,395 trace links, and we used two visualizations to examine the results. We provide initial suggestions as to how the knowledge embedded in such a network can be (re-)used to advance support for IA.

Software change impact analysis (CIA) is a key technique to identify the potential ripple effects of the changes to software. Coarse-grained CIA techniques such as file, class and method level techniques often gain less precise change impacts, which are difficult for practical use. Fine-grained CIA techniques, such as slicing, can be used to gain more precise change impacts, but need more time and space cost. In this paper, by combining the features of the coarse-grained technique and the fine-grained technique, a variable-method (VM) correlation-based CIA technique called VM-CIA is proposed to improve the precision of static CIA. First, the VM-CIA technique uses the abstract syntax tree (AST) of program to construct a novel intermediate representation called variable and method triple (VMT), which is used to analyze the correlation between the variables and methods. Second, the VM-CIA technique proposes the single-change impact analysis algorithm and multi-change impact analysis algorithm to compute the impact set based on the VMT representation. In addition, the VM-CIA technique can get a sorted impact set which is more accurate than the existing CIA techniques. The empirical results show that the VM-CIA technique can greatly improve the precision (19%) over traditional the CIA techniques, while at the cost of a little recall (5%). Moreover, the empirical studies also show that the VM-CIA technique predicts a ranked list of potential impact results according to the distance measure, which can greatly facilitate the practical use.

Software maintenance is the most demanding and effort-consuming phase in software development. It has been recognized as being a tedious step in software development process. Two basic activities in software maintenance are the understanding of the system and the assessment of the potential effects of a change. A change to a system, however small, can lead to several accidental effects, which are often not obvious and easy to identify. The main purpose of impact analysis is not only to find the impact set in terms of coding elements but also in terms of effort and resources required for implementing the change so that analysts could analyze the impact of the requested change in terms of budget. The objective of this paper is to find the impact set of the change requested by user or client. By using the impact set we estimate the regression test effort. We illustrate our results with a case study. As the results of this work, we get the impact set having impact element as class names with respect to the requested change, the test suite and the effort required for regression testing after the implementation of the requested change.

Traceability is defined by Center of Excellence for Software Traceability as the ability to interrelate any uniquely identifiable software engineering artifact to any other, maintain required links over time, and use resulting network to answer questions of both software product and its development process. It is an essential element in software development process, especially for Safety-Critical systems where trace links are used to demonstrate that all hazards and faults are mitigated in delivered system. Maintaining trace links as a software system evolves over time is difficult, error-prone and costly. As a result, trace links tend to become outdated and safety-cases, which rely on trace links and associated data to compose arguments and evidence for system safety are invalidated. In practice, software developers must therefore painstakingly update trace links in order to re-validate safety-cases whenever they seek re-certification of their product. While a significant body of work exists in area of trace link creation, very limited research has focused on problem of link evolution. The goal of this dissertation is therefore to deliver an accurate, scalable, and practical approach for supporting trace link evolution across a diverse set of software artifacts including requirements, source code and safety cases.

Maintaining traceability links among software artifacts is particularly important for many software engineering tasks. Even though automatic traceability link recovery tools are successful in identifying the semantic connections among software artifacts produced during software development, no existing traceability link management approach can effectively and automatically deal with software evolution. We propose a technique to automatically manage traceability link evolution and update the links in evolving software. Our novel technique, called incremental latent semantic indexing (iLSI), allows for the fast and low-cost LSI computation for the update of traceability links by analyzing the changes to software artifacts and by reusing the result from the previous LSI computation before the changes. We present our iLSI technique, and describe a complete automatic traceability link evolution management tool, TLEM, that is capable of interactively and quickly updating traceability links in the presence of evolving software artifacts. We report on our empirical evaluation with various experimental studies to assess the performance and usefulness of our approach.

FCA–CIA: An approach of using FCA to support cross-level change impact analysis for object oriented Java programs

Software change is inevitable in the process of software development. At present, there are a lot of researches on the methods of the change impact analysis, but most of them are aimed at a certain stage of the software development process, and these technologies are not suitable for other stages of software development. In this paper, based on the whole software development process, five kinds of entity dependency types and five types of change are proposed and formalized, and their properties are discussed. This paper is to provide a theoretical basis for the research of rule based change impact analysis in the software development process.

Small changes can have major and nonlocal effects in object oriented languages, due to the extensive use of subtyping and dynamic dispatch. This makes it difficult to understand value flow through a program and complicates life for maintenance programmers. Change impact analysis provides feedback on the semantic impact of a set of program changes.The change impact analysis method presented in this thesis presumes the existence of a suite of regression tests associated with a Java program and access to the original and edited versions of the code. The primary goal of our research is to provide programmers with tool support that can help them understand why a test is suddenly failing after a long editing session by isolating the changes responsible for the failure. The tool analyzes two versions of an application and decomposes their difference into a set of atomic changes. Change impact is then reported in terms of affected tests whose execution behavior may have been modified by the applied changes. For each affected test, it also determines a set of affecting changes that were responsible for the test's modified behavior.The first contribution of this thesis is the demonstration of the utility of the basic change impact analysis framework of [51], by implementing a proof-of-concept prototype, Chianti, and applying it to Daikon, for an experimental validation.The second contribution is the definition and implementation of the dependences between atomic changes. Extensive experiments show that our dependences can help build the intermediate programs automatically in most cases.Another contribution is the heuristics for ranking the atomic changes for fault localization. This thesis proposes a heuristic that ranks method changes that might have affected a failed test, indicating the likelihood that they may have contributed to a test failure. Our results indicate that when a failure is caused by a single method change, our heuristic ranked the failure-inducing change as number 1 or number 2 of all the method changes in 67% of the delegate tests (i.e., representatives of all failing tests).

In change impact analysis, obtaining guidance from automatic tools would be highly desirable since this activity is generally seen as a very difficult program comprehension problem. However, since the notion of an 'impact set' (or dependency set) of a specific change is usually very inexact and context dependent, the approaches and algorithms for computing these sets are also very diverse producing quite different results. The question 'which algorithm finds program dependencies in the most efficient way?' has been preoccupying researchers for a long time, but there are still very few results published on the comparison of the different algorithms to what programmers think are real dependencies. In this work, we report on our experiment conducted with this goal in mind using a compact, easily comprehensible Java experimental software system, simulated program changes, and a group of programmers who were asked to perform impact analysis with the help of different tools and on the basis of their programming experience. We show which algorithms turned out to be the closest to the programmers' opinion in this case study. However, the results also certified that most existing algorithms need to be further enhanced and an effective methodology to use automated tools to support impact analysis still needs to be found.

A systematic Change Impact Analysis (CIA) is being used for better change management of software. Also, CIA process is evolved continuously to make it more effective. Software metrics play an important role to evaluate CIA process. Two types of metrics are used to evaluate CIA. First types of metrics are the standard metrics used to evaluate the performance of CIA techniques for example Precision, Recall, F-measure etc. These are most commonly used by researchers. Second types of metrics are those which are used to quantify the change impact which is based on the code/design features. This paper is aimed at identification of these second types of metrics available in literature.