Components interact with each to provide the functionality of the product. The operating system field refers to the operating system on which the software was running on during the crash. The severity of a bug is often used as an indicator of how a bug negatively affects system functionality. It is used by developers to prioritize bugs which need to be fixed.

  • An extract from that list is shown in Table 4 below.
  • For example, ‘Left-behind Items’ represents everything in or close to the air-intake that can become FOD when inadvertently left behind.
  • Dicotyledonous ones in 1703, recognized the true affinities of the whales, and gave a workable definition of the species concept, which had already become the basic unit of biological classification.
  • Anglo-Saxon terms such as worm and fish have been used to refer, respectively, to any creeping thing—snake, earthworm, intestinal parasite, or dragon—and to any swimming or aquatic thing.
  • From the perspective of an MRO, a defect is a damage that may or may not exceed the tolerances set in the engine manual and may or may not be removed from service for repair or replacement.
  • In this paper we take a different perspective studying to what extent collecting data about sequences of function calls may impact the quality of the user experience, producing recognizable effects.

Based on these definitions, the two keywords refer to the ability of users to recognize and understand possible actions based on visual cues of user interface. The unclear separation between the keywords can lead to misclassification of defects that will eventually affect the identification of root cause and similar resolution strategies. In fact, the single perspective classification as used by Bugzilla is not relevant for classifying usability issues that often consist of graphical user interface and action issues. In this regard, a taxonomic classification such as UPT is a recommended approach to classify usability defects from an artefact and task aspect, respectively. However, Keenan’s approach to classification relies on a high quality defect description which, as our earlier work demonstrates , are rarely present in open source usability defect reports.

Project Level Taxonomies

A taxonomy is a system of hierarchical categories designed to be a useful aid for reproducibly classifying things. The book concludes with a very long literature list of 63 pages, suitably cross-referenced, covering the biology and taxonomy of solitary bees and wasps. Ironically, even though the taxonomy is segmented into elementary categories, it is difficult to find an approach based on these in many produced works. Connect and share knowledge within a single location that is structured and easy to search.

To avoid such unfavorable scenarios, we prepare the knowledge base. In the glossary we gather the main specialized terms that are frequently used in the working process. All meanings are written according to their generally accepted international interpretation. For convenience, you can use the search bar to simplify and speed up the search process. Can be further accelerated and aggravated by several factors, such as environmental conditions, fuel quality, operating settings, cyclic loads and engine and maintenance history.

By definition, a lexicon is in alphabetical order and contains a brief description of each defect. The research by Laskowski presents the direct cause for the defect only, but does not show the root-causes and how these interact and aggravate each other. The operation of modern gas turbines demands ever higher temperatures, pressures and rotational speeds to increase power and improve efficiency .

The list is more comprehensive than the Federal Aviation Administration handbook as it contains all potential defects that can be found on an aircraft. These defects are not limited to the engine but further include damages to the airframe, landing gear, electronics and control units. When performing borescope inspection of engine blades, most of the defects are not applicable. Usability engineering needs to make it feasible to be used in open source software development. The use of the taxonomy has been validated on five real cases of usability defects.

definition of defect taxonomy

As shown in Table 5, most of the evaluators are computing students and academic researchers, accounting for 48.8% and 29.3%, respectively. Almost 80% of the evaluators had received training or certification related to usability evaluation/ HCI/ UX. However, as indicated in Table 6, the majority of evaluators had limited familiarity in handling usability defects. Several other related work support usability-related issues by focusing on GUI defects and functionality.


In this study, we expand our previous work by exploring the effect of using categorical features, in addition to stack traces, to predict the severity of bugs. These categorical features include faulty product, faulty component, and operating system. We experimented with other features and observed that they do not improve the severity prediction accuracy. A Software system is composed of many products; each has a set of components.

definition of defect taxonomy

Engine manufacturers and MRO service providers use different terminologies to describe the same type of defect. Even within the same organisation different terminologies are used depending on the purpose of communication. For instance, the engine operator is only interested in what caused the damage to the engine as this determines whether the maintenance costs are covered by their insurance. That is the case if a foreign object damages the engine, but the insurance is not reliable if the cause can be traced back to an operational error, such as an overloaded aircraft.

The pressing need is for inclusion of an expert system. For the development of an expert system, we recommend to first determine the data properties and restrictions and create rules using Semantic Web Rule Language . The rules need to be added to the ontology and support complex mathematical expressions. Next, a semantic reasoner, that is Hermit, Pellet, Racer, Jess, etc. might be used to evaluate the rules for consistency and derive new, non-explicitly expressed knowledge .

Taxonomy of Gas Turbine Blade Defects

During engine maintenance, the first step of the inspection process comprises that all blades are visually inspected for defects or indications of damages. Borescopes are the most important optical aid to visually inspect the inside of the engine, which is otherwise inaccessible. Causal – Since no formal usability evaluation is usually conducted in OSS projects, usability problem triggers cannot be identified. In OSS projects, usability defects are most often reported from online user feedback facilities and results of developer black-box testing.

In the context of community open source software in which no specific software development processes were carried out, usability activities are often ignored. Volunteers are more focused on functionality and features rather than appearance, design aesthetic, and how people will use the products . As a result, open source projects often have poor interfaces and complex user interaction , . The everyday work of the software development specialists coupled with specialized vocabulary usage. It may be challenging for customers to understand it. Situations of misunderstanding between clients and team members could lead to an increase in overall project time.

definition of defect taxonomy

It is often aggravated by high air temperature, humidity, moisture and contaminated environments, such as salt from sea or de-icing treatments. The Aristotelian method dominated classification until the 19th century. These can then be used to develop a definition that states the essence of the living thing—what makes it what it is and thus cannot be altered; the essence is, of course, immutable. The model for this procedure is to be seen in mathematics, especially geometry, which fascinated the Greeks. Mathematics seemed to them the type and exemplar of perfect knowledge, since its deductions from axioms were certain and its definitions perfect, irrespective of whether a perfect geometrical figure could ever be drawn. But the Aristotelian procedure applied to living things is not by deduction from stated and known axioms; rather, it is by induction from observed examples and thus does not lead to the immutable essence but to a lexical definition.

In the existing ODC classification, severity is used to measure the degree of the defect impact. However, due to unclear usability category definitions, many usability defects end up with low severity ratings . However, the use of only textual descriptions to capture user difficulty could be a disadvantage as users are likely to provide lengthy explanations that may be unhelpful to many software developers. One way to reduce this limitation is to create a set of predefined impact attributes so that the impact can be objectively measured. For example, we can use rating scale to measure emotion, while task difficulty could be selected from a predefined set of attributes.

Because the taxonomy itself isn’t shown to users per se , it’s a place where we can be fully immersed in very precise and logical classification work. We are typically concerned with logical precision in a taxonomy, whereas in the visible navigation structure we are concerned with grouping things in a way that adheres to users’ mental models. Minimizing the resource wastage reduces the energy cost of operating a data center, but may also lead to a considerably high resource overcommitment affecting the Quality of Service of the running applications. The effective tradeoff between resource wastage and overcommitment is a challenging task in virtualized Clouds and depends on the allocation of virtual machines to physical resources.

Information and Software Technology

Other defects may be more apparent when the deposits are removed, e.g., surface damage. Identify the concepts that you will build your taxonomy around. These can be found in the content itself, any existing metadata (like keywords or topics in your content-management-system), discussions with subject-matter experts, and key internal business terms. The concepts should also be sourced from existing user data, such as that resulted from interviews, usability testing, and search logs to ensure that you don’t build out branches of the taxonomy that won’t benefit users. We used Web Ontology Language and Protégé software to build a knowledge base and express relationships, hierarchies and object properties, and applied mapping analysis to visualise the network. The ontology was developed based on the cause–defect table as shown in Table A1.

We felt it was not useful to list all those items, which only results in a massive ontology. Likewise, we did not further split up root-causes in subcategories. For example, for bird ingestion, we did not differentiate between say a sparrow and an albatross as the expected type of defect remains the same; only the extent of damage increases with increasing size of the ingested item.

Last, an easily accessible user interface needs to be developed to query information from the ontology. The user interface could be in form of a web-based homepage or offline application programmed in C++, Java, HTML, Visual Basic, etc. . The literature review revealed that most studies present the defects in alphabetical order and do not provide a categorisation system. Moreover, they analyse engine blade failures after a particular event has occurred. There appears to be no existing work that systematically describes root-causes of blade defects and the interrelations.

Consider the defects you want to target and their level of detail. If you had a similar software testing project you can get additional inspiration from it. Usually, a decision has to be made between the level of detail and the redundancies in the list. Taxonomies are a powerful way to build content relationships in digital products and are the unseen, backstage organization systems that fill in the gaps that user-facing navigation systems may leave.

The problem is that, for various reasons, bug submitters often enter the incorrect severity level, delaying the bug resolution process. Techniques that can automatically predict the severity of a bug can significantly reduce the bug triaging overhead. In our previous work, we showed that the accuracy of description-based severity prediction techniques could be significantly improved by using stack traces as a source of information. Considering all of these limitations, we revised Geng’s classification to better suit an OSS environment and adapted some elements of the ODC framework to address cause and effect attributes.

Geng’s classification , in our view, is not appropriate to classify open source usability defects that often contain limited information , , . The trigger component in the causal attributes can be limited. This is because in the absence of formal usability evaluations in OSS development, it is impossible to identify the usability evaluation methods that trigger usability defects. Effect – Previous studies have reported that usability defects are treated at a lower priority compared to functional defects .

In software test design we are primarily concerned with taxonomies of defects, ordered lists of common defects we expect to encounter in our testing. Each of these characteristics and subcharacteristics suggest areas of risk and thus areas for which tests might be created. An evaluation of the importance of these characteristics should be undertaken first so that the appropriate level of testing is performed. A similar „if you are concerned about / you might want to emphasize” process could be used based on the ISO 9126 taxonomy. The general goal of a defect taxonomy is to reduce the number of product defects that reach customers.

We propose in this paper a multi-objective method for dynamic VM placement, which exploits live migration mechanisms to simultaneously optimize the resource wastage, overcommitment ratio and migration energy. Our optimization algorithm uses a novel evolutionary meta-heuristic based on an island population model to approximate the Pareto optimal set of VM placements with good accuracy and diversity. Simulation results using traces collected from a real Google cluster demonstrate that our method outperforms related approaches by reducing the migration energy by up to 57% with a QoS increase below 6%. 4)to quantitatively track usability defects over time. A defect taxonomy is a method of gathering indications of problem areas. Mishra, R.; Thomas, J.; Srinivasan, K.; Nandi, V.; Raghavendra Bhatt, R. Failure analysis of an un-cooled turbine blade in an aero gas turbine engine.