| 1. |
- Kumari, Jaya, et al.
(författare)
-
MetaAnalyser - A Concept and Toolkit for Enablement of Digital Twin
- 2022
-
Ingår i: IFAC-PapersOnLine. - : Elsevier. - 2405-8963. ; 55:2, s. 199-204
-
Tidskriftsartikel (refereegranskat)abstract
- Digital Twin (DT) has promising impact on the life cycle management of assets in manufacturing industry. The concept of DT has become possible with digitalisation and Artificial Intelligence (AI). Data driven Machine Learning (ML) capabilities, can enhance the performance of the DT. To replicate a dynamic system, the DT should continuously receive and process incoming data in real-time. However, every time that the system receives new incoming datasets, the challenges of ML such as data preparation, feature selection, model selection and performance evaluation, slow down the development process of DT. This paper proposes a MetaAnalyser platform that automates these steps for incoming datasets in real-time. The MetaAnalyser platform through automating data preparation, feature selection, model selection and performance evaluation, is expected to increase the level of agility in the development process of DT and the efficiency of the DT during its lifecycle. The MetaAnalyser platform is demonstrated in this paper by ranking the features that affect the arrival delays in trains and ranking regression models based on their performance on the dataset.
|
|
| 2. |
- Ahmadi, Alireza, et al.
(författare)
-
Prerequisites for a business-oriented fleet availability assurance program in aviation
- 2010
-
Ingår i: Proceedings of the 1st international workshop and congress on eMaintenance. - Luleå : Luleå tekniska universitet. ; , s. 168-175
-
Konferensbidrag (refereegranskat)abstract
- The air transport business is a large, integrated, automated and complex domain with high requirements on safety, security and dependability. In order to achieve customer satisfaction and gain a global competitive advantage, provision of services is essential. In air transport business with an extensive competition, the consequences of unreliable services become more critical which may increase cost of operation and reduce productivity. Furthermore, occurrence of unreliable services might also lead to annoyance, inconvenience and a lasting customer dissatisfaction that can create serious problem with regarding the responsible company‟s marketplace position. Hence, it is crucial for air transport companies to continuously improve the quality of the services they provide to customer. In the context of air transport, maintenance process and maintenance-related services have a high impact on effectiveness, productivity and costs. Maintenance departments are required to ensure that their fleet is expected to meet, or continues to meet, airline‟s established availability performance goals (e.g. operational readiness, dispatch reliability and cost affectivity) and to ensure that demands for deliveries will met. One way to align maintenance decisions and business objectives and at the same time highlight where the potential weakness in the systems and maintenance performance can be expected, is through Fleet Availability Assurance Program (FAAP). However, an effective implementation of FAAP needs adaptation to the usage context. Hence, the purpose of this paper is to present an availability assurance program in airline industries, in which the essential functional elements of such a program are discussed. The paper also proposes an integrated information logistic infrastructure for this management system.
|
|
| 3. |
- Ahmadi, Alireza, et al.
(författare)
-
Selection of maintenance strategy for aircraft systems using multi-criteria decision making methodologies
- 2010
-
Ingår i: International Journal of Reliability, Quality and Safety Engineering (IJRQSE). - 0218-5393. ; 17:3, s. 223-243
-
Tidskriftsartikel (refereegranskat)abstract
- This paper, proposes the Multi-Criteria Decision Making (MCDM) methodology for selection of a maintenance strategy to assure the consistency and effectiveness of maintenance decisions. The methodology is based on an AHP-enhanced TOPSIS, VIKOR and benefit-cost ratio, in which the importance of the effectiveness appraisal criteria of a maintenance strategy is determined by the use of AHP. Furthermore, in the proposed methodology the different maintenance policies are ranked using the benefit-cost ratio, TOPSIS and VIKOR. The method provides a basis for consideration of different priority factors governing decisions, which may include the rate of return, total profit, or lowest investment. When the preference is the rate of return, the benefit-cost ratio is used, and for the total profit TOPSIS is applied. In cases where the decision maker has specific preferences, such as the lowest investment, VIKOR is adopted. The proposed method has been tested through a case study within the aviation context for an aircraft system. It has been found that using the methodology presented in the paper, the relative advantage and disadvantage of each maintenance strategy can be identified in consideration of different aspects, which contributes to the consistent and rationalized justification of the maintenance task selection. The study shows that application of the combined AHP, TOPSIS, and VIKOR methodologies is an applicable and effective way to implement a rigorous approach for identifying the most effective maintenance alternative.
|
|
| 4. |
- Al-Douri, Yamur K., et al.
(författare)
-
Improvement of Railway Performance : A Study of Swedish Railway Infrastructure
- 2016
-
Ingår i: Journal of Modern Transportation. - : Springer Science and Business Media LLC. - 2095-087X .- 2196-0577. ; 24:1, s. 22-37
-
Tidskriftsartikel (refereegranskat)abstract
- The volume of rail traffic was increased by 5% from 2006 to 2010, in Sweden, due to increased goods and passenger traffic. This increased traffic, in turn, has led to a more rapid degradation of the railway track, which has resulted in higher maintenance costs. In general, degradation affects comfort, safety, and track quality, as well as, reliability, availability, speed, and overall railway performance. This case study investigated the needs of railway stakeholders responsible for analysing the track state and what information is necessary to make good maintenance decisions. The goal is to improve the railway track performance by ensuring increased availability, reliability, and safety, along with a decreased maintenance cost. Interviews of eight experts were undertaken to learn of general areas in need of improvement, and a quantitative analysis of condition monitoring data was conducted to find more specific information. The results show that by implementing a long-term maintenance strategy and by conducting preventive maintenance actions maintenance costs would be reduced. In addition to that, problems with measured data, missing data, and incorrect location data resulted in increased and unnecessary maintenance tasks. The conclusions show that proactive solutions are needed to reach the desired goals of improved safety, improved availability and improved reliability. This also includes the development of a visualisation tool and a life cycle cost model for maintenance strategies.
|
|
| 5. |
- Al-Douri, Yamur K., et al.
(författare)
-
Information security in e-maintenance : a study of Scada security
- 2012
-
Konferensbidrag (refereegranskat)abstract
- eMaintenance solutions are spreading increasingly due to the continuous evolution in the different Information and Communication Technology (ICT) tools. In general, most of the available eMaintenance solutions are depending on Internet infrastructure what makes them vulnerable to all security threats that affect the Internet. One of the important eMaintenance solutions is Supervisory Control and Data Acquisition (SCADA) system as it has been used in most of the industrial processes. SCADA systems were designed without security considerations as they were mainly installed into isolated networks. Nowadays, SCADA systems are mainly connected to Internet and other networks. Therefore, SCADA systems have been exposed to wide range of network security threats. Hence, SCADA security has become an important aspect that needs to be investigated. In this paper, a study of SCADA security issues will be done. The main contribution of this paper is to address SCADA security issues and challenges related to eMaintenance.
|
|
| 6. |
- Al-Douri, Yamur K., et al.
(författare)
-
Model-based security system for data acquisition in e-maintenance using artificial immune system and cloud computing
- 2012
-
Ingår i: International Journal of COMADEM. - 1363-7681. ; 15:4, s. 26-37
-
Tidskriftsartikel (refereegranskat)abstract
- eMaintenance solutions are extensively used by the industry today. eMaintenance is an emerging technology aimed to support the industry to achieve effectiveness and efficiency in their maintenance process through enhanced use of Information and Communication Technology (ICT) . One of the essential components is an eMaintenance solution is data acquisition. Supervisory Control and Data Acquisition (SCADA) has been used to manage data acquisition is many industrial systems. Nowadays, modern SCADA systems are available through internet and other networks via IP protocol. An increased use of internet–based solution requires appropriate management approaches to improve the safety and security aspects of a system. Hence, this paper suggests a new security model based security for SCADA systems through Cloud computing and Artificial Immune System (AIS). Furthermore, the paper provides AIS, which is based on Decision Tree (C4.5 algorithm) using clustered feature set. The features set are selected from NSL-KDD cup. It is a new version of KDD dataset. As a result, two Antibodies are generated (that could recognize Normal and Antigen). After applying the resulted antibodies on the testing data set, the outputs are Normal, Antigen, and Unknown. Finally it is treated with Unknown as Antigen. As a result, high accuracy of the suggested model reaches 96.3%.
|
|
| 7. |
|
|
| 8. |
- Al-Jumaili, Mustafa, et al.
(författare)
-
Assessment of railway frequency converter performance and data quality using the IEEE 762 Standard
- 2014
-
Ingår i: International Journal of Systems Assurance Engineering and Management. - : Springer Science and Business Media LLC. - 0975-6809 .- 0976-4348. ; 5:1, s. 42694-
-
Tidskriftsartikel (refereegranskat)abstract
- Reliability, availability and maintainability analysis is one of the most important tools for measuring system performance. The performance of a traction power supply system (TPSS) can be measured using the data collected from frequency converters, as these converters constitute the main part of the TPSS. The quality of the collected data should be good enough to provide the correct and complete information necessary for assessment of frequency converter performance. Many methods can be used to assess the performance of converters such as neural networks, fuzzy logic and standards. The IEEE 762 Standard offers a methodology that can provide key performance indicators for power generation units. This standard has been chosen for its widespread acceptance and applicability. To be able to evaluate a converter’s performance, IEEE 762 indexes should be calculated using data such as the downtime, reserve shutdown hours and service hours. Therefore, the purpose of this study is to assess the performance of the Swedish TPSS frequency converters using IEEE 762, and to assess the quality of data by inspecting their compatibility with this standard. In this study, an application has been developed to generate the missing information and to calculate the indexes provided by the standard, in order to evaluate the power converters’ performance. A case with sample data is also discussed in this paper.
|
|
| 9. |
- Al-Jumaili, Mustafa, et al.
(författare)
-
Data quality assessment using multi-attribute : maintenance perspective
- 2018
-
Ingår i: International Journal of Information and Decision Sciences. - : InderScience Publishers. - 1756-7017 .- 1756-7025. ; 10:2, s. 147-161
-
Tidskriftsartikel (refereegranskat)abstract
- The paper proposes a model for data quality (DQ) assessment in maintenance. Data has become an increasingly important since most of the maintenance planning and implementations are based on data analysis. Poor DQ reduces customer satisfaction, leading to poor decision making, and has negative impacts on strategy execution. To improve DQ as well as to evaluate the current status, DQ needs to be measured. A measure for DQ could be an important support for decision makers. Multi-criteria decision-making (MCDM) methods can provide a framework for DQ assessment, however, they are not used in literature for DQ assessment. In order to assess DQ, the attributes or KPIs need to be defined, their hierarchy should be designed and the assessment model is proposed to evaluate these attributes. A case study is also presented in this paper. The study shows that MCDM methods could provide qualitative estimation for the quality of DQ attributes.
|
|
| 10. |
- Al-Jumaili, Mustafa, et al.
(författare)
-
Data quality in eMaintenance: a call for research
- 2011
-
Ingår i: MPMM 2011: Maintenance Performance Measurement & Management. - Luleå : Luleå tekniska universitet. - 9789174393798 ; , s. 69-73
-
Konferensbidrag (refereegranskat)abstract
- Effective and efficient maintenance requires a proper information logistics, which can be delivered through eMaintenance solutions. Development of eMaintenance solutions faces extensive challenges. One of these challenges is how to ensure the quality of data used in different eMaintenance solutions. Data Quality (DQ) concerns all phases of the maintenance process. The purpose of this paper is to answer the research question: how should DQ be considered and managed when developing eMaintenance solutions. To deal with such challenges a case study was conducted at a mining company. Empirical data has been collected through interviews, observations, archival records and workshops. The data analysis has been based on an empirical framework that supports the identification of required information services. Conditions that support the DQ and the information logistics, along with that, support the maintenance process have been presented. These aspects have also been related to the phases of a generic maintenance process.
|
|
