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  • 201.
    Wen, Wei
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics. Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Khatibi, Siamak
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Kajínek, Ondřej
    Czech Technical University, CZE.
    Chadzitaskos, Goce
    Czech Technical University, CZE.
    A Common Assessment Space for Different Sensor Structures2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 3, article id 568Article in journal (Refereed)
    Abstract [en]

    The study of the evolution process of our visual system indicates the existence of variational spatial arrangement; from densely hexagonal in the fovea to a sparse circular structure in the peripheral retina. Today’s sensor spatial arrangement is inspired by our visual system. However, we have not come further than rigid rectangular and, on a minor scale, hexagonal sensor arrangements. Even in this situation, there is a need for directly assessing differences between the rectangular and hexagonal sensor arrangements, i.e., without the conversion of one arrangement to another. In this paper, we propose a method to create a common space for addressing any spatial arrangements and assessing the differences among them, e.g., between the rectangular and hexagonal. Such a space is created by implementing a continuous extension of discrete Weyl Group orbit function transform which extends a discrete arrangement to a continuous one. The implementation of the space is demonstrated by comparing two types of generated hexagonal images from each rectangular image with two different methods of the half-pixel shifting method and virtual hexagonal method. In the experiment, a group of ten texture images were generated with variational curviness content using ten different Perlin noise patterns, adding to an initial 2D Gaussian distribution pattern image. Then, the common space was obtained from each of the discrete images to assess the differences between the original rectangular image and its corresponding hexagonal image. The results show that the space facilitates a usage friendly tool to address an arrangement and assess the changes between different spatial arrangements by which, in the experiment, the hexagonal images show richer intensity variation, nonlinear behavior, and larger dynamic range in comparison to the rectangular images.

  • 202.
    Widén, Jon
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Johansson, Michelle
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    BPMN flows as variation points for end user development: from a UX perspective2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Context. How end user development can be enabled and made attainable through the use of a web based graphical user interface, in systems that contains logic for handling BPMN flows as variation points. Investigated from a UX and usability perspective.

    Objectives. Designing prototypes of such a web-based interface, and then evaluating the usability with regards to the usability attributes effectiveness and learnability, with the goal finding relevant usability issues & solutions as well as investigating how the two usability attributes affected the participants’ subjective satisfaction.

    Methods. Two prototype versions were implemented, one based upon the other. A usability inspection (expert evaluation) was performed after the first prototype version (named alpha) was finished and the second version (named beta) was built based on that feedback. The usability of the prototypes were then evaluated in usability test sessions using the think aloud method together with the SUS (System Usability Scale) questionnaire.The recorded data from the usability test sessions was analysed. Usability issues & solutions were noted, filtered, tagged and grouped by design principle with the goal of looking for patterns. SUS scores were calculated from the questionnaires. Additional factor analysis was performed on the SUS data to get separate usability and learnability scores.

    Results. The results consisted of SUS scores for both prototypes together with learnability and usability scores. Common and noteworthy usability issues & solutions grouped by design principle. Detailed appendixes with scenarios exemplifying recorded video & voice data for four of the most relevant test participants.

    Conclusions. The two prototypes were compared. Improvements to effectiveness and learnability was found to have a positive impact on the participants’ subjective satisfaction in the described context. Additionally, a number of usability issues and solutions was identified that could be of value when developing similar software. In summary, the following findings were made related to effectiveness:

    • Adding constraints to the number of options available to users helped increase effectiveness.

    • The lack of keyboard shortcuts was a deal breaker for many users and had a negative impact on effectiveness..

    • Consistency in navigation was more important than expected.

    • The lack of functionality for saving drafts in the browser, without downloading, was something that most users expected and was surprised not to find.

    • Several users expected their drafts to be automatically saved. They were frustrated when their changes were lost without warning.

    • The lack of an undo function was also a big issue for users, causing problems with recovery.

    • Giving immediate feedback with a notification popup after users had deployed a flow worked well and was easier to implement than expected.

    • The connection tool that ship with bpmn-js was hard to learn and use for several users.

    Additionally, some learnability related findings:

    • Sandbox intended to boost learnability but caused problems with effectiveness.

    • The BPMN notation was not familiar to the test participants. Some training or introduction would have been necessary in a real usage scenario.

    • When important functionality was concealed in submenus it was harder for users to learn how to operate the editor, specifically a problem with the context pad.

    • Properties panel. Issues with visibility of single items due to tabs being too cluttered. Affordance issues on input/output parameters tab. Consistency issue with the bpmn.io logo being placed in the where users expected a save button.

    • Consistency. Negative impact on learnability due to lack of keyboard shortcuts. Users likely to learn faster if they could use the shortcuts they already know. Placement of the download button not consistent with other webapps. Unconventional to only have drag and drop for upload and no button.

    • Issues with visibility and consistency related to maximizing/minimizing editor in beta prototype.

    • Familiarity findings related to deploy button colour and label might have affected learnability.
  • 203.
    Woxberg, Lars
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Grahn, Stefan
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Maritime Anomaly Detection with Dynamic Potential Field Grids2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context. Safety and security in the maritime domain is an important area and systems designed to aid in detecting illegal or dangerous situations are desired. With the advent of Automatic Identification Systems (AIS), information about marine traffic is in abundance and the challenge is in finding events of interest; to which a common approach is to find vessels behaving anomalously.

    Objectives. This study extends previous work by Osekowska et al. who used potential fields to condensate AIS data into a unified pattern. The challenge in this method is the configuration of grid precision. Through the use of quadtrees, this thesis presents a new implementation that intends to alleviate this problem by allowing dynamic grid resolution.

    Methods. Experiments are conducted to compare the new implementation to the existing one. Both algorithms are tested in areas with dense, sparse and mixed traffic density. Additionally, the implementations are validated against real anomaly data and a set of traffic data containing no confirmed anomalies.

    Results. While the new algorithm does not work exactly like the existing implementation in dense and sparse areas, it is shown to be able to detect 8/9 real anomalies while detecting 20.1\% false positives. The existing implementation either finds 5/9 of the real anomalies and 8.3\% false positives with a large cell size or 7/9 real anomalies and 44.4\% false positives with a small cell size.

    Conclusions. The new algorithm finds more real anomalies, especially compared to when using a large cell size. It finds fewer false positives than when using small cells, but not quite as few as with large cells. The anomaly missed by the new algorithm is likely due to the fact that traffic patterns have changed after the training data was collected, and it is possible that it would have been found with more up-to-date training data. This thesis is a pre-study of the presented method and provides incentive for future investigation. 

  • 204.
    Yusuf, Adewale
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Challenges associated with effective task execution in a Virtual Learning Environment: A case study of Graduate Students of a University2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context: In recent years, more and more people have started showing an increasing interest in distance or web-based education. Some of the reasons for this are the improvement in information and communication technology, as well as advancement in computer networking infrastructures. However, although computer technology has played an important role for the development of distance learning management systems, the underlying goal of such systems is the delivery of competitive and qualitative education via the distance learning environment. There have been a number of research studies and investigations in the field of Computer supported collaborative learning. This particular study is focused on the challenges associated with task execution in a distance learning environment as perceived by graduate students at a university.

    Objectives: The main focus or rationale behind this study is to investigate the importance of computer mediated communication tools in a virtual learning environment, as well as the problems facing the teachers or facilitators in their attempt to help learners (students) in the process of task execution, and towards achieving the learning goals in a web-based learning system.

    Methods: The author has adopted a qualitative case study approach. Questionnaires were sent out to some of the graduate students of BTH that participated in the online course under investigation, “Work integrated e-learning”, and some of these students were interviewed as well. Interviews were also conducted with two professors of Informatics and active researchers in distributed or e-learning in a University in Sweden that has had many years of experience in providing distance learning education. The empirical material was then analyzed, using cultural historical activity theory (CHAT) as a theoretical framework

    Results: The results indicate that more communication and collaborative interaction is needed in the context of the studied e-learning management system. The students expected the provision of more video communication through the learning platform. Furthermore, the results show that the learning in the studied web-based environment is centered on the students. 

    Conclusions: The author concludes that in order to diminish the gap that exists between face-to-face learning/teaching and an e-learning environment, there is a need for the designers and facilitators of the e-learning management system to make this platform more interactive. Additionally, the author concludes that the concept of Open start free pace (OSFP) or strict deadlines may need to be introduced into distance learning education in order to solve the challenges facing the teachers and facilitators.  

     

  • 205.
    Zepernick, Hans-Juergen
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies. Blekinge Inst Technol, SE-37179 Karlskrona, Sweden..
    Toward Immersive Mobile Multimedia: Opportunities, Challenges, and Enablers2018In: 2018 12TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS) / [ed] Wysocki, TA Wysocki, BJ, IEEE , 2018Conference paper (Refereed)
    Abstract [en]

    In recent years, we have seen an increasing interest in immersive mobile multimedia applications and services. Advanced human-machine interfaces (HMIs) and related head-mounted displays (HMDs) support different levels of computer-generated virtual worlds. These worlds include mobile virtual reality (VR), mobile augmented reality (VR), and mobile mixed reality (MR) which are jointly captured under the term mobile extended reality (XR). In addition, the development of fifth generation (5G) mobile networks aims at catering for ultra-reliable low-latency communications such as mobile XR and the tactile Internet. In this context, 5G mobile networks are essential enablers to carry mobile XR beyond video gaming to the general consumer and industry markets. In this keynote lecture, the fundamentals of interconnected immersive mobile multimedia are reviewed, and opportunities, challenges, and enablers are discussed. An overview of immersive mobile multimedia from mobile video to mobile 360-degree video, mobile VR, mobile AR, mobile MR, and mobile XR is provided. Major components of interconnected immersive mobile multimedia will be discussed and application opportunities in different vertical industries are pointed out. Furthermore, challenges associated with the delivery of immersive mobile XR applications are shown through service integrity parameters. Several enablers for interconnected immersive mobile multimedia applications are highlighted including standardization activities.

  • 206.
    Zepernick, Hans-Juergen
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Chu, Thi My Chinh
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Descriptive Statistical Analysis of Subjective Experiments in Mobile Imaging2017In: 11th International Conference on Signal Processing and Communication Systems, ICSPCS 2017 / [ed] Wysocki, TA Wysocki, BJ, IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    In this paper, we provide a descriptive statistical analysis of subjective experiments in mobile imaging. Most of the statistical analyses of such experiments use condensed statistics such as mean opinion scores along with standard deviations. These statistics give only limited insights on the underlaying distribution of a data set. On the other hand, higher order statistics such as skewness and kurtosis provide additional information about a distribution but their qualitative interpretation is complicated. In order to alleviate these shortcomings, we advocate the use of box plots to efficiently visualize and compare distributions between different sets of image quality scores. Specifically, box plots serve the purposes of accounting for the diversity in image quality scores as well as supporting an intuitive qualitative interpretation of the results. It is shown by analysing two subjective experiments of the wireless imaging quality database that notched box plots are beneficial in quickly assessing the statistical significance among differences in such experiments. Further, box plots are used to identify those test material that received a wide diversity in image quality scores including outliers.

  • 207.
    Zhao, Jie
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Wen, Wei
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics. Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Image Quality Assessment of Enriched Tonal Levels Images2017In: Image and Graphics 9th International Conference, ICIG 2017, Shanghai, China, September 13-15, 2017, Revised Selected Papers, Part II / [ed] Yao Zhao, Xiangwei Kong, David Taubman, Springer, 2017, p. 134-146Conference paper (Refereed)
    Abstract [en]

    The quality assessment of a high dynamic image is a challenging task. The few available no reference image quality methods for high dynamic range images are generally in evaluation stage. The most available image quality assessment methods are designed to assess low dynamic range images. In the paper, we show the assessment of high dynamic range images which are generated by utilizing a virtually flexible fill factor on the sensor images. We present a new method in the assessment process and evaluate the amount of improvement of the generated high dynamic images in comparison to original ones. The results show that the generated images not only have more number of tonal levels in comparison to original ones but also the dynamic range of images have significantly increased due to the measurable improvement values.

  • 208.
    Örtegren, Kevin
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Clustered Shading: Assigning arbitrarily shaped convex light volumes using conservative rasterization2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context. In this thesis, a GPU-based light culling technique performed with conservative rasterization is presented. Accurate lighting calculations are expensive in real-time applications and the number of lights used in a typical virtual scene increases as real-time applications become more advanced. Performing light culling prior to shading a scene has in recent years become a vital part of any high-end rendering pipeline. Existing light culling techniques suffer from a variety of problems which clustered shading tries to address.

    Objectives. The main goal of this thesis is to explore the use of the rasterizer to efficiently assign convex light shapes to clusters. Being able to accurately represent and assign light volumes to clusters is a key objective in this thesis.

    Methods. This method is designed for real-time applications that use large amounts of dynamic and arbitrarily shaped convex lights. By using using conservative rasterization to assign convex light volumes to a 3D cluster structure, a more suitable light volume approximation can be used. This thesis implements a novel light culling technique in DirectX 12 by taking advantage of the hardware conservative rasterization provided by the latest consumer grade Nvidia GPUs. Experiments are conducted to prove the efficiency of the implementation and comparisons with AMD´s Forward+ tiled light culling are provided to relate the implementation to existing techniques.

    Results. The results from analyzing the algorithm shows that most problems with existing light culling techniques are addressed and the light assignment is of high quality and allows for easy integration of new convex light types. Assigning the lights and shading the CryTek Sponza scene with 2000 point lights and 2000 spot lights takes 2.92ms on a GTX970.

    Conclusions. The conclusion shows that the main goal of the thesis has been reached to the extent that all existing problems with current light culling techniques have been solved, at the cost of using more memory. The technique is novel and a lot of future work is outlined and would benefit the validity of the implementation if further researched.

2345 201 - 208 of 208
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