Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal. Feature Papers represent the most advanced research with significant potential for high impact in the field. Feature Papers are submitted upon individual invitation or recommendation by the scientific editors and undergo peer review prior to publication. These example sentences are selected automatically from various online news sources to reflect current usage of the word ‘defect.’ Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors.

definition of defect taxonomy

It is important to understand the ontology as a support tool and not as a means to skip the inspection for any other defect type. Consequently, the ontology approach is not yet robust enough that it could be given to maintenance technicians to use. Pratt and Whitney uses a ‘Standard Practices Manual for Visual Inspection’ and the ‘IAE V2500 Maintenance Manual’ that provide a similar list of defects. 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.

Defect Taxonomy

First, many of the volunteers who contribute to OSS development are developers, who generally have limited knowledge and skills required for usability evaluation. Second, in order to formally conduct usability evaluations, extra commitment from contributors is necessary, but volunteers may not be able to spend the time on this. Several other related work support usability-related issues by focusing on GUI defects and functionality. No taxonomy has a one-fits-all property – it’s likely to require some modifications to fit the product your testing for. Consider the defects you want to target and their level of detail.

A similar „if you are concerned about / you might want to emphasize” process could be used based on the ISO 9126 taxonomy. Marandi, S.M.; Tajdari, M.; Rahmani, K.H. Foreign object damage on the leading edge of compressor blades. Cowles, B.A. High cycle fatigue in aircraft gas turbines—An industry perspective. Oberle, D.; Eberhart, A.; Staab, S.; Volz, R. Developing and managing software components in an ontology-based application server.

The specific area under examination in this paper is the visual inspection of engine blades and vanes. This paper focuses on defining engine blade defects, highlighting the differences definition of defect taxonomy between them and providing a taxonomy system. Moreover, it proposes a method to link potential causes to the defects, and show the inter-relationships and cascade effects.

Aspects that can be used in forming the taxonomy

Nor have we addressed the other ‘Damage Attributes’ identified above. Nonetheless, in principle, such additional data could be added to the table as additional fields. To structure our defect collection, https://globalcloudteam.com/ we looked into a possible classification system. There are several ways of categorising defects, corresponding to the lenses or perspectives of the audiences, as shown in Table 1.

They typically apply a reliability-centred maintenance methodology, whereby they seek to identify and manage failures to preserve the technical functionality, and hence safety and airworthiness of the engine. Most defects that can lead to failures are detected during maintenance inspection before any negative effects appear on flight operations. Early failure detection ensures low engine failure rates during flight operation . The maintenance inspection is primarily by visual means . The most rejected engine parts are blades and vanes from compressor and turbine sections . During engine maintenance, the first step of the inspection process comprises that all blades are visually inspected for defects or indications of damages.

Second, the ontology does not provide an easy mechanism for forward or backward chaining, which is needed for the prediction and diagnosis activities. A related limitation of the ontology is its limited export options. We could not find software, such as an expert system, that was able to further process the data without additional extensive code writing. The cause–defect list is believed to be adequate for the maintenance audience since it was validated in that field, but we caution that it may not be sufficiently exhaustive for the accident investigation audience. This is because a defect can result from multiple causes, and a cause can lead to multiple defects.

When performing borescope inspection of engine blades, most of the defects are not applicable. Although Geng et al. agreed that CUP can capture important usability defect information and provide feedback for usability software, CUP could not be used to analyse the effect on users and task performance. Considering the importance of the cause – effect relationship, they have customized the ODC and UPT, as shown in Fig.

definition of defect taxonomy

The user interface could be in form of a web-based homepage or offline application programmed in C++, Java, HTML, Visual Basic, etc. . Finally, we assigned the causes to the resulting defects. This was challenging as causes can lead to one or multiple defects, resulting in a complex intertwined network. The goal was to present it in an integrated and coherent manner. As there are multiple categorisations, we applied the ontology methodology to develop a logical representation structure. The benefit of an ontology is to visually present the relationships between different defects, causes and contributing factors in an appealing and easy-to-absorb way.

Improvement of Open Source Software Usability: an Empirical Evaluation from Developers’ Perspective

In this paper, we propose a novel set of quality attributes to evaluate refactored ATL programs based on the hierarchical quality model QMOOD. We recommend that organizations allocate novice developers for identifying code smells in collaboration. Thus, these organizations can promote the knowledge sharing and the correct smell identification. We also recommend the allocation of developers that are unfamiliar with the system for identifying smells.

definition of defect taxonomy

In Proceedings of the 5th ACM/IFIP/USENIX international conference on Middleware, Toronto, ON, Canada, 18–20 October 2004; pp. 459–477. Choi, Y.-S.; Lee, K.-H. Investigation of blade failure in a gas turbine. Dewangan, R.; Patel, J.; Dubey, J.; Prakash, K.; Bohidar, S. Gas turbine blades—A critical review of failure at first and second stages. Chipping describes mechanical separation of small pieces of blade material or coating often apparent on edges, corners or surfaces leaving a sharply roughened area of irregular shape.

Project Level Taxonomies

In Section 5, we elaborate our new usability defect classification model. We present our approach to evaluate the model in Section 6, and the evaluation results are presented in Section 7 and Section 8, respectively. We outline threats to validity in Sections 9 and we discuss some important issues in Section 10. The paper concludes with a summary, implications, and future work in Section 11. This paper defines engine blade defects, assigns root-causes, shows causal links and cascade effects and provides a taxonomy system. Defect types were identified from the literature and maintenance manuals, and categorised into Surface Damage, Wear, Material Separation and Material Deformation.

We used the proposed quality attributes to guide the selection of the best refactorings to improve ATL programs using multi-objective search. Statistical testing suggests 27% more precision and 36% more recall through the collaborative smell identification for both novices and professionals. These results partially confirm previous work in a not previously exploited scenario. Additionally, the interviews showed that leaders would strongly adopt the collaborative smell identification.

  • In order to improve the engine efficiency, the clearance between blades and casing shall be kept as minimal as possible.
  • For example, consider a search job that uses a lot of computer resources.
  • This represented the complex relations and interactions between defects, causes and temporal progression of events.
  • However, it may have resulted in operational variations, such as higher fuel consumption due to deterioration of the airflow.
  • The operation of modern gas turbines demands ever higher temperatures, pressures and rotational speeds to increase power and improve efficiency .

The authors declare no other conflict of interest. Beside nonconformities in terminology, there are defect definitions that contradict each other. For example, there is inconsistency about whether material is removed and displaced or only displaced . Please let us know what you think of our products and services. Find support for a specific problem in the support section of our website.

Using the ISO/IEC 9126 product quality model to classify defects: a Controlled Experiment

This has potential to support aircraft engine inspectors to guide their maintenance tasks, as well as investigators to identify the root-causes after a defect may lead to severe damage. The second limitation is that the defect list has been created for visual inspection only. It does not include any defects or damages that can be detected by applying other NDT methods commonly used in aviation maintenance, such as ultrasonic, radiography, eddy current, three-dimensional laser or infrared thermography .

Impact of End User Human Aspects on Software Engineering

Once the usability defects have been fixed, the developers record four attributes in Post-CUP. For example, technical information about defect removal activity, failure qualifier, expected phase, and frequency are difficult to obtain, especially for those who have limited usability-technical knowledge. There have been several studies in the literature investigating failures of gas turbine blades after an incident or accident by applying metallurgical , mechanical or chemical analysis or other analytical methods .

We propose that potential causes vary for different types of defects. For example, we divided ‘Corrosion’ further into three subcategories, namely oxidation, pitting and sulfidation. In the aircraft maintenance discipline, the term ‘defect’ is used to represent a component failure mode, which arises either from an intrinsic defect or an external event, and which becomes evident over time. This paper aims to compare manual FL against automated FL in models to answer important questions about performance, productivity, and satisfaction of both treatments. Software trustworthiness is a highly important research topic.

Comparing manual and automated feature location in conceptual models: A Controlled experiment

The taxonomy that is most useful is your taxonomy, the one you create from your experience within your organization. Often the place to start is with an existing taxonomy. Then modify it to more accurately reflect your particular situation in terms of defects, their frequency of occurrence, and the loss you would incur if these defects were not detected and repaired. In software test design we are primarily concerned with taxonomies of defects, ordered lists of common defects we expect to encounter in our testing. Let’s start with something we can all agree on – a defect is something not working as it should.

This may support the inspection task by guiding the worker during the inspection process, and help prioritise such inspections as may be necessary to determine the health of the engine. Can be further accelerated and aggravated by several factors, such as environmental conditions, fuel quality, operating settings, cyclic loads and engine and maintenance history. In the case of crack development, contributing factors include salty air and vibrations, whereby hail could be the initiator for the breaking of blade material. This type of defect development is unable to be represented by simple lists.