| 1. |
- A.V., Fidalgo, et al.
(author)
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Adapting remote labs to learning scenarios : Case studies using VISIR and remotElectLab
- 2014
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In: Revista Iberoamericana de Tecnologias del Aprendizaje. - : Education Society of IEEE (Spanish Chapter). - 1932-8540. ; 9:1, s. 33-39
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Journal article (peer-reviewed)abstract
- Remote laboratories are an emergent technological and pedagogical tool at all education levels, and their widespread use is an important part of their own improvement and evolution. This paper describes several issues encountered on laboratorial classes, on higher education courses, when using remote laboratories based on PXI systems, either using the VISIR system or an alternate in-house solution. Three main issues are presented and explained, all reported by teachers, that gave support to students' use of remote laboratories. The first issue deals with the need to allow students to select the actual place where an ammeter is to be inserted on electric circuits, even incorrectly, therefore emulating real-world difficulties. The second one deals with problems with timing when several measurements are required at short intervals, as in the discharge cycle of a capacitor. In addition, the last issue deals with the use of a multimeter in dc mode when reading ac values, a use that collides with the lab settings. All scenarios are presented and discussed, including the solution found for each case. The conclusion derived from the described work is that the remote laboratories area is an expanding field, where practical use leads to improvement and evolution of the available solutions, requiring a strict cooperation and information-sharing between all actors, i.e., developers, teachers, and students.
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| 2. |
- Aaboen, Lise, 1978, et al.
(author)
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Nourishment for the piggy bank : facilitation of external financing in incubators
- 2011
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In: International Journal of Technology Transfer and Commercialisation. - : Inderscience. - 1470-6075 .- 1741-5284. ; 10 3-4, s. 354-374
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Journal article (peer-reviewed)abstract
- In this paper, we argue that incubators facilitate access to external financing for their incubatees. Incubators use a wide range of activities to facilitate the accessing of external financing from public and private sources. We have grouped these into two sets of activities. The general activities aim to develop the conditions for external financing through information, education of incubatees, network-building and lobbying activities. The specific activities aim to assist the individual incubatee in their pursuit of external finance through help in application procedures, establishing need for capital, making contacts with the best public or private investor, etc. Based on the survey data, we have also shown that it is more common for incubatees to attract external capital compared to non-incubator firms. The incubatees seem especially successful in attracting public capital. The incubatees also attract more private external capital, however, the observed frequency of private capital in the incubatees are low.
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| 3. |
- Abarkan, Abdellah
(author)
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The study of urban form in Sweden
- 2009
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In: Urban Morphology. - : INT SEMINAR URBAN FORM. - 1027-4278. ; 13:2, s. 121-127
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Journal article (peer-reviewed)abstract
- Early research on urban form in Sweden was undertaken before the First World War. After the Second World War research was influenced by the major criticisms levelled at comprehensive urban renewal and suburban mass housing. These criticisms were particularly on the ground that values embodied in the traditional built environment were being ignored. Increased interest in the study of historical urban fabrics was associated with the development of methodologies reliant on the concepts of typology and morphology. These development were dependent on the activities of individual researchers until the very recent development of wider co-ordinating research organizations.
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| 4. |
- Abbas, Zeshan, et al.
(author)
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Influence of Patterns on Mechanical Properties of Ultrasonically Welded Joints in Copper Substrate and Wire
- 2024
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In: Metals and Materials International. - : Springer Nature. - 1598-9623 .- 2005-4149.
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Journal article (peer-reviewed)abstract
- Ultrasonic wire welding is considered a method of choice for creating reliable interconnects in electronics industry including aerospace, batteries and electric vehicles. In this paper, ultrasonic welding tests between EVR252 copper wire and substrate are carried out. Novel pattern morphologies are machined on substrates to explore its influence on mechanical properties of welded joint. Patterns are divided into three different categories e.g., original surface, vertical and horizontal shapes. Cracks, microstructure strength and tensile properties of welded joint are studied and its joining mechanism is analysed. Compared with the reference substrate (S1), the welded joint performance of the longitudinal patterns (S2, S3, S4) has been improved, among which the longitudinal pattern (S4) has the most significant improvement (+ 15%). Likewise, the performance of transverse pattern (S5) welded joints is relatively poor (− 16%). The microstructural analysis using SEM has revealed predominant joint strength on Cu wire surface while maintaining rock-like and compact properties of S4 substrate. Upper side of wire-harness compactness is frequently observed due to vertical direction of patterns on substrate and also increases the strength of welded joint. Values of failure load, failure displacement and failure energy absorption were increased by 7.9%, 72% and 35% for S2, 6.1%, 75% and 42% for S3 and 15%, 87% and 113% for S4 compared to S1. Failure modes of welded joints are mainly characterized into: 1-poor ductility or rupture (no deformation) failure in vertical 3-line pattern joints 2-cylindrical deep holes failure in vertical 3-line zigzag pattern joints and 3-bulging effect failure in horizontal 3-line zigzag pattern joints. Point and line scans EDS measurement were performed to investigate weaker and stable trends of different locations in welded joints. In S4 substrate, 17.9% carbon content at the position of welded joint was investigated, leading to content of less oxides and fraction impurities. However, S1 weld zone contains 38.7% carbon content which can weaken welded joint and reduce durability. Graphical Abstract: (Figure presented.). © The Author(s) under exclusive licence to The Korean Institute of Metals and Materials 2024.
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| 5. |
- Abbas, Zeshan, et al.
(author)
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Investigation of forming quality and failure behaviours of multilayered welded joints using ultrasonic double roller welding
- 2024
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In: Alexandria Engineering Journal. - : Elsevier. - 1110-0168 .- 2090-2670. ; 107, s. 491-506
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Journal article (peer-reviewed)abstract
- Ultrasonic metal welding machines are suitable for various complex applications (e.g., battery tabs) through unique mechanical design, special pressure application methods and high-precision welding. This work reports the weldability, forming quality and fractographic analysis of copper multilayered welded joints which were studied by SEM-EDS characterization, micro-hardness testing and tensile testing based on ultrasonic double roller welding (UDRW). Three groups of process parameters (A, B and C) were established to investigate the performance, production quality and welded joint surface interconnections. The tensile testing results of sample under parameter 3 in group A [S-P3(A)] indicate the maximum tensile strength of 69.859 N in T-peel test while the average tensile strength has increased by 58.525 N due to rise in welding time from 2 sec to 5 sec. The results analysis indicates that welding quality features in S-P3(A) joints under 4 bar, 100 mm/s, 45 % have been exploited. The over-welded zone was transformed into good-welded zone. The micro-cracks, fatigue stations and peeling texture in multilayers were reduced. It was found that when the welding energy was 10000 J then the tearing edges and interlayers cracks were minimized while keeping the other parameters constant. Moreover, when the amplitude increased up to 50 %, then numerous micro-cracks and micro-fissure stations were created, which leads to the occurrence of fracture in multi-layer welded joint. The EDS study investigated that the complex features are formed at the interface junction of sample 3 S3(A) in multilayer welds. The complex multilayer microstructures can induce and produce unique hardness properties for battery manufacturing. It leads to high quality and durable welds. Eventually, it is experimentally demonstrated that robust 40 layer welded joints can be obtained by the UDRW process. Data availability: The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. © 2024 The Authors
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| 6. |
- Abbas, Zeshan, et al.
(author)
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Surface-conformed approach for mechanical property analysis using ultrasonic welding of dissimilar metals
- 2024
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In: The International Journal of Advanced Manufacturing Technology. - : Springer Science+Business Media B.V.. - 0268-3768 .- 1433-3015. ; 132:7-8, s. 3447-3466
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Journal article (peer-reviewed)abstract
- In this paper, dissimilar aluminum (Al) and copper (Cu) metals were joined together using ultrasonic metal welding (USMW), a solid-state welding technology. From the perspective of increasing the base metal welding contact area, the Cu/Al mating surface was innovatively prepared and ultrasonically welded. A comprehensive analysis was carried out on the forming quality, welding process temperature, interface structure, and mechanical properties of the welded joint. Defect-free and squeezed welds were successfully achieved by machining novel patterns especially C4-2. The results indicated that the reference joint can withstand higher loads, but its failure mode is very unstable. Failure may occur at welded interface and on the aluminum plate which is not good for actual production applications. Welded strength of reference joint was 4493 N, and the welded strength of C4-2 joint was 3691 N. However, microscopic analysis discovered that the welded joint internal morphology in C4-2 was more stable and hardest. C4-2 joint has successfully achieved higher tensile strength and stability under failure displacement of 38% which is higher than C4-1 joint. All welded joint failures occurred on aluminum plate, indicating that the joint strength is higher than that of bottom plate. This is attributed to unique structural design of chiseled joint and lesser thickness. SEM–EDS results investigated that the C4-2 joint can transfer more energy to area under welding head which provides welded joint with robust diffusion capacity. The transition layer has a higher thickness while the energy transferred to area away from welding head was smaller. Thickness of transition layer is significantly reduced and reference joint has similar diffusion characteristics. Conversely, the thickness of the transition layer at the corresponding position is smaller than that of pattern morphology. This is due to overall smaller thickness of the pattern joint which is more conducive to the transfer of welding energy. The surface-conformed approach and comprehensive temperature analysis provide a new understanding of USMW in dissimilar welded metals. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2024.
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| 7. |
- Abdeen, Waleed, et al.
(author)
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An approach for performance requirements verification and test environments generation
- 2023
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In: Requirements Engineering. - : Springer. - 0947-3602 .- 1432-010X. ; 28:1, s. 117-144
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Journal article (peer-reviewed)abstract
- Model-based testing (MBT) is a method that supports the design and execution of test cases by models that specify theintended behaviors of a system under test. While systematic literature reviews on MBT in general exist, the state of the arton modeling and testing performance requirements has seen much less attention. Therefore, we conducted a systematic map-ping study on model-based performance testing. Then, we studied natural language software requirements specificationsin order to understand which and how performance requirements are typically specified. Since none of the identified MBTtechniques supported a major benefit of modeling, namely identifying faults in requirements specifications, we developed thePerformance Requirements verificatiOn and Test EnvironmentS generaTion approach (PRO-TEST). Finally, we evaluatedPRO-TEST on 149 requirements specifications. We found and analyzed 57 primary studies from the systematic mappingstudy and extracted 50 performance requirements models. However, those models don’t achieve the goals of MBT, whichare validating requirements, ensuring their testability, and generating the minimum required test cases. We analyzed 77 Soft-ware Requirements Specification (SRS) documents, extracted 149 performance requirements from those SRS, and illustratethat with PRO-TEST we can model performance requirements, find issues in those requirements and detect missing ones.We detected three not-quantifiable requirements, 43 not-quantified requirements, and 180 underspecified parameters in the149 modeled performance requirements. Furthermore, we generated 96 test environments from those models. By modelingperformance requirements with PRO-TEST, we can identify issues in the requirements related to their ambiguity, measur-ability, and completeness. Additionally, it allows to generate parameters for test environments
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| 8. |
- Abdelraheem, Mohamed Ahmed, et al.
(author)
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Executing Boolean queries on an encrypted Bitmap index
- 2016
-
In: CCSW 2016 - Proceedings of the 2016 ACM Cloud Computing Security Workshop, co-located with CCS 2016. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450345729 ; , s. 11-22
-
Conference paper (peer-reviewed)abstract
- We propose a simple and efficient searchable symmetric encryption scheme based on a Bitmap index that evaluates Boolean queries. Our scheme provides a practical solution in settings where communications and computations are very constrained as it offers a suitable trade-off between privacy and performance.
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| 9. |
- Abghari, Shahrooz, et al.
(author)
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A Higher Order Mining Approach for the Analysis of Real-World Datasets
- 2020
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In: Energies. - : MDPI. - 1996-1073. ; 13:21
-
Journal article (peer-reviewed)abstract
- In this study, we propose a higher order mining approach that can be used for the analysis of real-world datasets. The approach can be used to monitor and identify the deviating operational behaviour of the studied phenomenon in the absence of prior knowledge about the data. The proposed approach consists of several different data analysis techniques, such as sequential pattern mining, clustering analysis, consensus clustering and the minimum spanning tree (MST). Initially, a clustering analysis is performed on the extracted patterns to model the behavioural modes of the studied phenomenon for a given time interval. The generated clustering models, which correspond to every two consecutive time intervals, can further be assessed to determine changes in the monitored behaviour. In cases in which significant differences are observed, further analysis is performed by integrating the generated models into a consensus clustering and applying an MST to identify deviating behaviours. The validity and potential of the proposed approach is demonstrated on a real-world dataset originating from a network of district heating (DH) substations. The obtained results show that our approach is capable of detecting deviating and sub-optimal behaviours of DH substations.
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| 10. |
- Abghari, Shahrooz, et al.
(author)
-
District Heating Substation Behaviour Modelling for Annotating the Performance
- 2020
-
In: Communications in Computer and Information Science. - Cham : Springer. - 9783030438869 ; , s. 3-11
-
Conference paper (peer-reviewed)abstract
- In this ongoing study, we propose a higher order data mining approach for modelling district heating (DH) substations’ behaviour and linking operational behaviour representative profiles with different performance indicators. We initially create substation’s operational behaviour models by extracting weekly patterns and clustering them into groups of similar patterns. The built models are further analyzed and integrated into an overall substation model by applying consensus clustering. The different operational behaviour profiles represented by the exemplars of the consensus clustering model are then linked to performance indicators. The labelled behaviour profiles are deployed over the whole heating season to derive diverse insights about the substation’s performance. The results show that the proposed method can be used for modelling, analyzing and understanding the deviating and sub-optimal DH substation’s behaviours. © 2020, Springer Nature Switzerland AG.
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