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  • 2351.
    Chebudie, Abiy Biru
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Monitoring of Video Streaming Quality from Encrypted Network Traffic: The Case of YouTube Streaming2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The video streaming applications contribute to a major share of the Internet traffic. Consequently, monitoring and management of video streaming quality has gained a significant importance in the recent years. The disturbances in the video, such as, amount of buffering and bitrate adaptations affect user Quality of Experience (QoE). Network operators usually monitor such events from network traffic with the help of Deep Packet Inspection (DPI). However, it is becoming difficult to monitor such events due to the traffic encryption. To address this challenge, this thesis work makes two key contributions. First, it presents a test-bed, which performs automated video streaming tests under controlled time-varying network conditions and measures performance at network and application level. Second, it develops and evaluates machine learning models for the detection of video buffering and bitrate adaptation events, which rely on the information extracted from packets headers. The findings of this work suggest that buffering and bitrate adaptation events within 60 second intervals can be detected using Random Forest model with an accuracy of about 70%. Moreover, the results show that the features based on time-varying patterns of downlink throughput and packet inter-arrival times play a distinctive role in the detection of such events.

  • 2352.
    Cheddad, Abbas
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Structure Preserving Binary Image Morphing using Delaunay Triangulation2017In: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 85, p. 8-14Article in journal (Refereed)
    Abstract [en]

    Mathematical morphology has been of a great significance to several scientific fields. Dilation, as one of the fundamental operations, has been very much reliant on the common methods based on the set theory and on using specific shaped structuring elements to morph binary blobs. We hypothesised that by performing morphological dilation while exploiting geometry relationship between dot patterns, one can gain some advantages. The Delaunay triangulation was our choice to examine the feasibility of such hypothesis due to its favourable geometric properties. We compared our proposed algorithm to existing methods and it becomes apparent that Delaunay based dilation has the potential to emerge as a powerful tool in preserving objects structure and elucidating the influence of noise. Additionally, defining a structuring element is no longer needed in the proposed method and the dilation is adaptive to the topology of the dot patterns. We assessed the property of object structure preservation by using common measurement metrics. We also demonstrated such property through handwritten digit classification using HOG descriptors extracted from dilated images of different approaches and trained using Support Vector Machines. The confusion matrix shows that our algorithm has the best accuracy estimate in 80% of the cases. In both experiments, our approach shows a consistent improved performance over other methods which advocates for the suitability of the proposed method.

  • 2353.
    Cheddad, Abbas
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Towards Query by Text Example for pattern spotting in historical documents2016In: Proceedings - CSIT 2016: 2016 7th International Conference on Computer Science and Information Technology, IEEE Computer Society, 2016, article id 7549479Conference paper (Refereed)
    Abstract [en]

    Historical documents are essentially formed of handwritten texts that exhibit a variety of perceptual environment complexities. The cursive and connected nature of text lines on one hand and the presence of artefacts and noise on the other hand hinder achieving plausible results using current image processing algorithm. In this paper, we present a new algorithm which we termed QTE (Query by Text Example) that allows for training-free and binarisation-free pattern spotting in scanned handwritten historical documents. Our algorithm gives promising results on a subset of our database revealing ∌83% success rate in locating word patterns supplied by the user.

  • 2354.
    Cheddad, Abbas
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Kusetogullari, Hüseyin
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Grahn, Håkan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Object recognition using shape growth pattern2017In: Proceedings of the 10th International Symposium on Image and Signal Processing and Analysis, ISPA, IEEE Computer Society Digital Library, 2017, p. 47-52, article id 8073567Conference paper (Refereed)
    Abstract [en]

    This paper proposes a preprocessing stage to augment the bank of features that one can retrieve from binary images to help increase the accuracy of pattern recognition algorithms. To this end, by applying successive dilations to a given shape, we can capture a new dimension of its vital characteristics which we term hereafter: the shape growth pattern (SGP). This work investigates the feasibility of such a notion and also builds upon our prior work on structure preserving dilation using Delaunay triangulation. Experiments on two public data sets are conducted, including comparisons to existing algorithms. We deployed two renowned machine learning methods into the classification process (i.e., convolutional neural network-CNN- and random forests-RF-) since they perform well in pattern recognition tasks. The results show a clear improvement of the proposed approach's classification accuracy (especially for data sets with limited training samples) as well as robustness against noise when compared to existing methods.

  • 2355.
    Cheema, Rukhsar Ahmad
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Irshad, Muhammad Jehanzeb
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Issues and Optimization of UMTS Handover2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    UMTS is an emerging cell phone technology and it is basically another name for 3G mobile communication systems. It provides an enhanced range of multimedia services like video conferencing and high speed internet access. Sometimes UMTS is marketed as 3GSM emphasizing the both 3G nature and GSM standards which it was designed to succeed. UMTS is also European term for wireless systems based on the IMT-2000 standards. To utilize various merits in mobile telecommunication system which consist of various radio access networks, UMTS as Third Generation wireless technology utilizes a wideband CDMA or TD/CDMA transceiver and also cover large area. Handover is basically a function which continues the communication between users without any gaps when the hardware goes to a place where it finds no network coverage. When we talk in terms of cellular communications systems, handover is a process which is referred to the transfer of a connection from one cell to another. Handover time is generally between 200 and 1,200 milliseconds (ms), which accounts for the delay. In this thesis we are going to find the reasons for these factors which affect the Quality of service of handover. The main focus of this research is to study the some factors which really affect the handover phenomenon in UMTS that basically affect the overall quality of mobile network. For this we intend to find the solution for problems which born during the handover. Handover provides the mobility to users which are the main theme of wireless technology and it is also make the interoperability between different network technologies.

  • 2356.
    Chekkilla, Avinash Goud
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Monitoring and Analysis of CPU Utilization, Disk Throughput and Latency in servers running Cassandra database: An Experimental Investigation2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context Light weight process virtualization has been used in the past e.g., Solaris zones, jails in Free BSD and Linux’s containers (LXC). But only since 2013 is there a kernel support for user namespace and process grouping control that make the use of lightweight virtualization interesting to create virtual environments comparable to virtual machines.

    Telecom providers have to handle the massive growth of information due to the growing number of customers and devices. Traditional databases are not designed to handle such massive data ballooning. NoSQL databases were developed for this purpose. Cassandra, with its high read and write throughputs, is a popular NoSQL database to handle this kind of data.

    Running the database using operating system virtualization or containerization would offer a significant performance gain when compared to that of virtual machines and also gives the benefits of migration, fast boot up and shut down times, lower latency and less use of physical resources of the servers.

    Objectives This thesis aims to investigate the trade-off in performance while loading a Cassandra cluster in bare-metal and containerized environments. A detailed study of the effect of loading the cluster in each individual node in terms of Latency, CPU and Disk throughput will be analyzed.

    Method We implement the physical model of the Cassandra cluster based on realistic and commonly used scenarios or database analysis for our experiment. We generate different load cases on the cluster for Bare-Metal and Docker and see the values of CPU utilization, Disk throughput and latency using standard tools like sar and iostat. Statistical analysis (Mean value analysis, higher moment analysis and confidence intervals) are done on measurements on specific interfaces in order to show the reliability of the results.

    Results Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments. A statistical analysis summarizing the performance of Cassandra cluster while running single Cassandra is surveyed.

    Conclusions With the detailed analysis, the resource utilization of the database was similar in both the bare-metal and container scenarios. From the results the CPU utilization for the bare-metal servers is equivalent in the case of mixed, read and write loads. The latency values inside the container are slightly higher for all the cases. The mean value analysis and higher moment analysis helps us in doing a finer analysis of the results. The confidence intervals calculated show that there is a lot of variation in the disk performance which might be due to compactions happening randomly. Further work can be done by configuring the compaction strategies, memory, read and write rates.

  • 2357.
    Chekwube, Zikora Azubuike
    Blekinge Institute of Technology, School of Engineering.
    Building a timer controller circuit, with password access2013Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    The microcontroller and the coding is the heart of making a timer. The strategic release planning is gotten from the concept of how a door machine with password access functions. In this thesis project, all that has been studied in school such as circuit theory, electronics, digital design and microprocessors basic and programming course are combined to the success of this project. Therefore the objective is producing a practical knowledge of what has been studied which is the timer with password access. The method used was an inspiration gotten after reviewing many materials in some respective topic related to designing a timer. The particular method comes from creating an SPI Interface from the Programmer to the Microcontroller to Make Transferring More Convenient. The performance of the MCU, LCD and keypad was just as was expected in the software code and hardware also. The password is inputted, timer is set appropriately and timer runs till port is opened. To conclude, the result can be achieved in different method but this method was for an easy method for beginners.

  • 2358.
    Chen, Cenan
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Fan, Rong
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Vehicle Seat Structure Play Analysis and Method Development2018Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    With the development of the vehicle industry and the innovation of technology, driving experience is improving in all aspects. Volvo is more and more focusing on improving the comfort of driving. Part of this is to minimize squeaks and rattle (S&R) from vehicle seats. A physical measurement method was studied from component level in this thesis. The communication with the supplier has helped to better understand the definition and measurement method of play. Based on the previous work from Volvo and the supplier, a new improved algorithm has been developed to suit current production demands in this thesis work. A Graphical User Interface (GUI) has been finished for general engineers. The Study and exploration of a FEM simulation method make it possible to measure play in an economical way in the future.

  • 2359.
    Chen, Chen
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Dilley, Maura
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Valente, Marco
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Improving Decision Support Systems for Water Resource Management2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The Water Framework Directive (WFD) structures long-term plans for Europe's threatened water resources. Owning to the inherent and human-made complexities of the water cycle, stakeholders must move strategically to avoid crisis and restore sustainability. Yet, the reality of water resource management today is falling short on delivery. Stakeholders require strategic tools that will help them to build consensus and take action in the right direction. Using the Framework for Strategic Sustainable Development (FSSD), this study shows how Decision Support Systems can be strategically improved using a whole-systems approach grounded in basic Principles for Sustainability. In this way, stakeholders will be capable of making synchronized moves towards sustainability and thus more likely to realize the WFD’s goal of ‘good status’ for all European waterways by 2015.

  • 2360.
    Chen, Gaojun
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Lin, Sen
    Blekinge Institute of Technology, School of Engineering.
    Design, Implementation and Comparison of Demodulation Methods in AM and FM2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Modulation and demodulation hold dominant positions in communication. Communication quality heavily relies on the performance of the detector. A simple and efficient detector can improve the communication quality and reduce the cost. This thesis reveals the pros and cons of five demodulation methods for Amplitude Modulated (AM) signal and four demodulation methods for Frequency Modulated (FM) signal. Two experimental systems are designed and implemented to finish this task. This thesis provides the researchers an easier reference of demodulation methods with tables listing their pros and cons.

  • 2361.
    Chen, Guo
    Blekinge Institute of Technology, Faculty of Engineering, Department of Spatial Planning.
    Migrating Cities: How to redefine the regional development in China2015Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    With the rapid development of the urbanization in China, more and more migrants who are mainly from the relatively poor areas move to big cities in order to obtain the economic benefits. However, rather than living condition of migrants and rural development, people pay more attention to the economic development of the city. Migrants cannot achieve reasonable living condition in the urban context, at the same time, they may lose their land and source of income if they come back hometown although they have devoted themselves to the construction of big cities and economic development of rural areas. I analyze the characters of migrants’ living conditions in the big cities and the transfer of labors in rural areas, claiming that we should consider the situation of migrants scientifically when we are conducting the urban planning and urbanization. To explain the phenomenon of migration intuitively, I choose the Zhejiang village in Beijing and four villages in Henan Province as the example to study and analysis in the following. Firstly, Beijing is the capital of China so that it is the most popular place for migrants to move in. Zhejiang village is the famous historic problem in China and there are a lot of literatures and data collections that can be useful for my thesis. Secondly, Henan Province has the largest population in China and the migration is popular there. After the case study and survey, I analyze the reasons of the problem from different perspective such as government, economic differences, migrants’ education and so on. The paper suggests the solutions to solve the problems from relevant aspects.

  • 2362.
    Chen, Hao
    et al.
    Kunming University of Science & Technology, CHN.
    Li, Xuechao
    Kunming University of Science & Technology, CHN.
    Wan, Rundong
    Kunming University of Science & Technology, CHN.
    Kao-Walter, Sharon
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Fac. of Mech. & El. Eng., Shanghai Second Polytechnic Univ., 201209 Shanghai, China.
    Lei, Ying
    Anhui University of Technology, CHN.
    A DFT study of the electronic structures and optical properties of (Cr, C) co-doped rutile TiO22018In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 501, p. 60-67Article in journal (Refereed)
    Abstract [en]

    To get an effective doping model of rutile TiO2, we systematically study geometrical parameters, density of states, electron densities, dielectric functions, optical absorption spectra for the pure, C mono-doping, Cr mono-doping and (Cr,C) co-doping rutile TiO2, using density functional calculations. We find that a C doped system presents higher stability under Ti-rich condition, while Cr doped and (Cr,C) co-doped systems are more stable under O-rich condition. For (Cr,C) co-doping situation, the imaginary part of the dielectric function reflects the higher energy absorption efficiency for incident photons. Moreover, co-doping system exhibits much bigger red-shift of optical absorption edge compared with Cr/C single doping systems, because of the great reduction of the direct band gap. The calculated optical absorption spectra show that the (Cr,C) co-doping rutile TiO2 has higher photocatalytic activity in the visible light region.

  • 2363.
    Chen, Hao
    et al.
    Kunming University of Science & Technology, CHI.
    Li, Xuechao
    Kunming University of Science & Technology, CHI.
    Wan, Rundong
    Kunming University of Science & Technology, CHI.
    Kao-Walter, Sharon
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Lei, Ying
    Anhui University of Technology, CHI.
    Leng, Chongyan
    Kunming University of Science & Technology, CHI.
    A DFT study on modification mechanism of (N,S) interstitial co-doped rutile TiO22018In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 695, p. 8-18Article in journal (Refereed)
    Abstract [en]

    To obtain a more efficient (N,S) co-doping scheme, we systematically analyze the geometrical parameters, density of states, charge densities, relative dielectric functions and UV–Vis absorption spectra for pure, N/S substitution/interstitial doped and (N,S) substitution/interstitial co-doped TiO2 by using density functional calculations. Compared with (N,S) substitution co-doping, (N,S) interstitial co-doping TiO2 exhibits a more obvious red-shift of absorption edge, because of the band gap is further reduced. Furthermore, there are shallow impurity levels coupling with the top of valence band. The calculated UV–Vis absorption spectra illustrate that (N,S) interstitial co-doping TiO2 has much higher photocatalytic activity in the visible light region. © 2018

  • 2364.
    Chen, Hao
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Xu, Luyang
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Software Architecture and Framework for Programmable Automation Controller: A Systematic Literature Review and A Case Study2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background. PAC controller is a strengthened version of PLC controller. Its function is very similar, but its essence and construction are different. PLC and PAC have many successful applications in the field of industrial automation control. There is a lot of literature about the software architecture of PLC control system. However, there is almost no relevant literature on software architecture based on PAC control system. A well-performing and stable automatic control system is indispensable to the design and development of suitable software architecture. The quality and pattern of software architecture can even affect the stability and efficiency of the control system.

    Objectives. Based on these problems, we defined two primary objectives. The first is to investigate the architecture of some existing large industrial control systems, to analyze and summarize the scenarios and advantages and disadvantages of these architectural patterns. The second, based on the results of effort for the first objective, we want to propose and design a set of automated control solution architecture model based on PAC control system, which is implemented and applied in a printing house. In the process, we sum up the challenges and obstacles encountered in implementing the solution and provide some guidance or reference for those involved in the field.

    Methods. For the first objective, we used a systematic literature review to collect data about existing ICS architecture. Concerning the second objective, a case study was conducted in a printing house in Karlskrona Sweden, in the study, we proposed a software architecture model suitable for PAC automation control system. Then, we developed and tested the automation control system and summarized some challenges and obstacles in the process of the implementation.

    Results. The existing ICS (Industrial Control System) architecture models and critical problems and challenges in the implementation of ICS are identified. From the existing literature, we have summarized five commonly used large industrial control system architecture models, which are mainly using composite structures, that is, a combination of multiple architecture patterns. Also, some critical problems in the industrial control system, such as information security, production reliability, etc. are also identified. In the case study, we put forward an automatic control solution for Printing House based on SLR results. We designed the hardware deployment architecture of the system and the software control architecture. Generally speaking, this architecture is based on C/S architecture. In the development of client, we adopt the popular MVC architecture mode. In the longitudinal view of the whole system, an extended hierarchical architecture model is adopted. In the core control system, we adopt the modular architecture design idea. The whole control system is composed of 6 parts, four subsystems of PAC terminal, one server-side program and one client program. After a long time, development and test, our system finally goes online for the production, and its production efficiency is improved compared with the old system. Its expansion functions, such as Production Report and Tag Print, are deeply satisfying for the customers.

    Conclusions. In this research, we summarize and compare the advantages and disadvantages of several commonly used industrial control systems. Besides, we proposed a software architecture model and developed an automation control system based on PAC. We fill the gap that there is a lack of studies about the software architecture about the implementation of the automation control system based on PAC. Our result can help software engineers and developers in ICS fields to develop their own PAC based automation control system.

  • 2365. Chen, Hong
    et al.
    Nie, Zedong
    Ivanov, Kamen
    Wang, Lei
    Liu, Ran
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    A statistical MAC protocol for heterogeneous-traffic human body communication2013Conference paper (Refereed)
    Abstract [en]

    In wireless body sensor networks (WBSN) and wireless body area networks (WBAN), sensor nodes have different bandwidth requirements, therefore, heterogeneous traffic is created. In this paper, we propose a statistical medium access control (MAC) protocol with periodic synchronization for use in heterogeneous traffic networks based on human body communication (HBC). The MAC protocol is designated to ensure energy efficiency by means of flexible time slot allocation and a statistical frame. The statistical frame is intended to increase the sleep time and keep low duty cycles in each beacon period. The MAC protocol was fully implemented on our HBC platform. The experimental results proved that the proposed MAC protocol is compact and energy-efficient.

  • 2366. Chen, Jiandan
    A Multi Sensor System for a Human Activities Space: Aspects of Planning and Quality Measurement2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In our aging society, the design and implementation of a high-performance autonomous distributed vision information system for autonomous physical services become ever more important. In line with this development, the proposed Intelligent Vision Agent System, IVAS, is able to automatically detect and identify a target for a specific task by surveying a human activities space. The main subject of this thesis is the optimal configuration of a sensor system meant to capture the target objects and their environment within certain required specifications. The thesis thus discusses how a discrete sensor causes a depth spatial quantisation uncertainty, which significantly contributes to the 3D depth reconstruction accuracy. For a sensor stereo pair, the quantisation uncertainty is represented by the intervals between the iso-disparity surfaces. A mathematical geometry model is then proposed to analyse the iso-disparity surfaces and optimise the sensors’ configurations according to the required constrains. The thesis also introduces the dithering algorithm which significantly reduces the depth reconstruction uncertainty. This algorithm assures high depth reconstruction accuracy from a few images captured by low-resolution sensors. To ensure the visibility needed for surveillance, tracking, and 3D reconstruction, the thesis introduces constraints of the target space, the stereo pair characteristics, and the depth reconstruction accuracy. The target space, the space in which human activity takes place, is modelled as a tetrahedron, and a field of view in spherical coordinates is proposed. The minimum number of stereo pairs necessary to cover the entire target space and the arrangement of the stereo pairs’ movement is optimised through integer linear programming. In order to better understand human behaviour and perception, the proposed adaptive measurement method makes use of a fuzzily defined variable, FDV. The FDV approach enables an estimation of a quality index based on qualitative and quantitative factors. The suggested method uses a neural network as a tool that contains a learning function that allows the integration of the human factor into a quantitative quality index. The thesis consists of two parts, where Part I gives a brief overview of the applied theory and research methods used, and Part II contains the five papers included in the thesis.

  • 2367. Chen, Jiandan
    An Intelligent Multi Sensor System for a Human Activities Space---Aspects of Quality Measurement and Sensor Arrangement2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In our society with its aging population, the design and implementation of a highperformance distributed multi-sensor and information system for autonomous physical services become more and more important. In line with this, this thesis proposes an Intelligent Multi-Sensor System, IMSS, that surveys a human activities space to detect and identify a target for a specific service. The subject of this thesis covers three main aspects related to the set-up of an IMSS: an improved depth measurement and reconstruction method and its related uncertainty, a surveillance and tracking algorithm and finally a way to validate and evaluate the proposed methods and algorithms. The thesis discusses how a model of the depth spatial quantisation uncertainty can be implemented to optimize the configuration of a sensor system to capture information of the target objects and their environment with required specifications. The thesis introduces the dithering algorithm which significantly reduces the depth reconstruction uncertainty. Furthermore, the dithering algorithm is implemented on a sensor-shifted stereo camera, thus simplifying depth reconstruction without compromising the common stereo field of view. To track multiple targets continuously, the Gaussian Mixture Probability Hypothesis Density, GM-PHD, algorithm is implemented with the help of vision and Radio Frequency Identification, RFID, technologies. The performance of the tracking algorithm in a vision system is evaluated by a circular motion test signal. The thesis introduces constraints to the target space, the stereo pair characteristics and the depth reconstruction accuracy to optimize the vision system and to control the performance of surveillance and 3D reconstruction through integer linear programming. The human being within the activity space is modelled as a tetrahedron, and a field of view in spherical coordinates are used in the control algorithms. In order to integrate human behaviour and perception into a technical system, the proposed adaptive measurement method makes use of the Fuzzily Defined Variable, FDV. The FDV approach enables an estimation of the quality index based on qualitative and quantitative factors for image quality evaluation using a neural network. The thesis consists of two parts, where Part I gives an overview of the applied theory and research methods used, and Part II comprises the eight papers included in the thesis.

  • 2368. Chen, Jiandan
    The depth reconstruction accuracy in a stereo vision system2009Conference paper (Refereed)
    Abstract [en]

    A 3D space can be reconstructed from the images produced by a pair of digital vision sen-sors. However, due to the digital sensor the reconstructed space is discretized and its quanti-sation levels are defined by the iso-disparity surfaces. Thus, the accuracy of the space depth reconstruction is related to the iso-disparity map. A validation of the reconstruction techniques requires a measurement with a high accu-racy reference. This paper introduces an easily implemented method based on a differential depth measurement. The modelling and analysis of the quantization uncertainty of the depth and differential depth measurements is presented in the paper. The model is verified through simulations, and further verified by a physical experiment.

  • 2369. Chen, Jiandan
    et al.
    Adebomi, Oyekanlu Emmanuel
    Olusayo, Onidare Samuel
    Kulesza, Wlodek
    The Evaluation of the Gaussian Mixture Probability Hypothesis Density Approach for Multi-target Tracking2010Conference paper (Refereed)
    Abstract [en]

    This paper describes the performance of the Gaussian Mixture Probability Hypothesis Density (GM-PHD) filter for multiple human tracking in an intelligent vision system. Human movement trajectories were observed with a camera and tracked by the GM-PHD filter. The filter multi-target tracking ability was validated by two random motion trajectories in the paper. To evaluate the filter performance in relation to the target movement, the motion velocity and angular velocity as key evaluation factors were proposed. A circular motion model was implemented for simplified analysis of the filter tracking performance. The results indicate that the mean absolute error defined as the difference between the filter prediction and the ground truth is proportional to the motion speed and angular velocity of the target. The error is only slightly affected by the tracking targets’ number.

  • 2370. Chen, Jiandan
    et al.
    Ghadami, Soheil
    Kulesza, Wlodek
    Evaluation of the GM-PHD filter for multi-target tracking with a stereo vision system2011Conference paper (Refereed)
    Abstract [en]

    This paper evaluates the performance of the Gaussian Mixture Probability Hypothesis Density (GM-PHD) filter for tracking multiple targets in an intelligent vision system. A stereo vision camera is used to get the left and right image sequences in order to extract 3-D coordinates of the targets' positions in the real world scene. The 3-D trajectories of the targets are tracked by a GM-PHD filter. Moreover, the label continuity of the targets is guaranteed by a new method of labeling. Motion speed and angular velocity are proposed for the evaluation of the accuracy and label continuity of the filter in the implemented 3-D test motion model. The simulation results for two moving targets show that the proposed system not only robustly tracks them, but also maintains the label continuity of the two targets.

  • 2371.
    Chen, Jiandan
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Khatibi, Siamak
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Kulesza, Wlodek
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Depth reconstruction uncertainty analysis and improvement: The dithering approach2010In: Image and Vision Computing, ISSN 0262-8856, E-ISSN 1872-8138, Vol. 29, no 9, p. 1377-1385Article in journal (Refereed)
    Abstract [en]

    The depth spatial quantization uncertainty is one of the factors which influence the depth reconstruction accuracy caused by a discrete sensor. This paper discusses the quantization uncertainty distribution, introduces a mathematical model of the uncertainty interval range, and analyzes the movements of the sensors in an Intelligent Vision Agent System. Such a system makes use of multiple sensors which control the deployment and autonomous servo of the system. This paper proposes a dithering algorithm which reduces the depth reconstruction uncertainty. The algorithm assures high accuracy from a few images taken by low-resolution sensors. The dither signal is estimated and then generated through an analysis of the iso-disparity planes. The signal allows for control of the camera movement. The proposed approach is validated and compared with a direct triangulation method. The simulation results are reported in terms of depth reconstruction error statistics. The physical experiment shows that the dithering method reduces the depth reconstruction error.

  • 2372. Chen, Jiandan
    et al.
    Khatibi, Siamak
    Kulesza, Wlodek
    Planning of a Multi Stereo Visual Sensor System Depth Accuracy and Variable Baseline Approach2007Conference paper (Refereed)
  • 2373. Chen, Jiandan
    et al.
    Khatibi, Siamak
    Kulesza, Wlodek
    Planning of a Multi Stereo Visual Sensor System for a Human Activities Space2007Conference paper (Refereed)
  • 2374. Chen, Jiandan
    et al.
    Khatibi, Siamak
    Wirandi, Jenny
    Kulesza, Wlodek
    Planning of a Multi Sensor System for Human Activities Space – Aspects of Iso-disparrity Surface2007Conference paper (Refereed)
    Abstract [en]

    The Intelligent Vision Agent System, IVAS, is a system for automatic target detection, identification and information processing for use in human activities surveillance. This system consists of multiple sensors, and with control of their deployment and autonomous servo. Finding the optimal configuration for these sensors in order to capture the target objects and their environment to a required specification is a crucial problem. With a stereo pair of sensors, the 3D space can be discretized by an iso-disparity surface, and the depth reconstruction accuracy of the space is closely related to the iso-disparity curve positions. This paper presents a method to enable planning the position of these multiple stereo sensors in indoor environments. The proposed method is a mathematical geometry model, used to analyze the iso-disparity surface. We will show that the distribution of the iso-disparity surface and the depth reconstruction accuracy are controllable by the parameters of such model. This model can be used to dynamically adjust the positions, poses and baselines lengths of multiple stereo pairs of cameras in 3D space in order to get sufficient visibility and accuracy for surveillance tracking and 3D reconstruction. We implement the model and present uncertainty maps of depth reconstruction calculated while varying the baseline length, focal length, stereo convergence angle and sensor pixel length. The results of these experiments show how the depth reconstruction uncertainty depends on stereo pair’s baseline length, zooming and sensor physical properties.

  • 2375. Chen, Jiandan
    et al.
    Mustafa, Wail
    Siddig, Abu Bakr
    Kulesza, Wlodek
    APPLYING DITHERING TO IMPROVE DEPTH MEASUREMENT USING A SENSOR-SHIFTED STEREO CAMERA2010In: Metrology and Measurement Systems, ISSN 0860-8229, Vol. 17, no 3Article in journal (Refereed)
    Abstract [en]

    The sensor-shifted stereo camera provides the mechanism for obtaining 3D information in a wide field of view. This novel kind of stereo requires a simpler matching process in comparison to convergence stereo. In addition to this, the uncertainty of depth estimation of a target point in 3D space is defined by the spatial quantization caused by the digital images. The dithering approach is a way to reduce the depth reconstruction uncertainty through a controlled adjustment of the stereo parameters that shift the spatial quantization levels. In this paper, a mathematical model that relates the stereo setup parameters to the iso-disparities is developed and used for depth estimation. The enhancement of the depth measurement accuracy for this kind of stereo through applying the dithering method is verified by simulation and physical experiment. For the verification, the uncertainty of the depth measurement using dithering is compared with the uncertainty produced by the direct triangulation method. A 49% improvement of the uncertainly in the depth reconstruction is proved.

  • 2376. Chen, Jiandan
    et al.
    Olayanju, Iyeyinka Damilola
    Ojelabi, Olabode Paul
    Kulesza, Wlodek
    RFID Multi-Target Tracking Using the Probability Hypothesis Density Algorithm for a Health Care Application2011Conference paper (Refereed)
    Abstract [en]

    The intelligent multi-sensor system is a system for target detection, identification and information processing for human activities surveillance and ambient assisted living. This paper describes RFID multi-target tracking using the Gaussian Mixture Probability Hypothesis Density, GM-PHD, algorithm. The multi target tracking ability of the proposed solution is demonstrated in a simulation and real environment. A performance comparison of the Levenberg-Marquardt algorithm with and without the GM-PHD filter shows that the GM-PHD algorithm improves the accuracy of tracking and target position estimation significantly. This improvement is demonstrated by a simulation and by a physical experiment.

  • 2377.
    Chen, Mingda
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    He, Yao
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Exploration on Automated Software Requirement Document Readability Approaches2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context. The requirements analysis phase, as the very beginning of software development process, has been identified as a quite important phase in the software development lifecycle. Software Requirement Specification (SRS) is the output of requirements analysis phase, whose quality factors play an important role in the evaluation work. Readability is a quite important SRS quality factor, but there are few available automated approaches for readability measurement, because of the tight dependency on readers' perceptions. Low readability of SRS documents has a serious impact on the whole process of software development. Therefore, it's extremely urgent to propose effective automated approaches for SRS documents readability measurement. Using traditional readability indexes to analyze readability of SRS documents automatically is a potentially feasible approach. However, the effectiveness of this approach is not systematically evaluated before.

    Objectives. In this study, firstly, we aim to understand the readability of texts and investigate approaches to score texts readability manually. Then investigate existing automated readability approaches for texts with their working theories. Next, evaluate the effectiveness of measuring the readability of SRS documents by using these automated readability approaches. Finally, rank these automated approaches by their effectiveness.

    Methods. In order to find out the way how human score the readability of texts manually and investigate existing automated readability approaches for texts, systematic literature review is chosen as the research methodology. Experiment is chosen to explore the effectiveness of automated readability approaches.

    Results. We find 67 articles after performing systematic literature review. According to systematic literature review, human judging the readability of texts through reading is the most common way of scoring texts readability manually. Additionally, we find four available automated readability assessments tools and seven available automated readability assessments formulas. After executing the experiment, we find the actual value of effectiveness of all selected approaches are not high and Coh-Metrix presents the highest actual value of effectiveness of automated readability approach among the selected approaches.

    Conclusions. Coh-Metrix is the most effective automated readability approach, but the feasibility in directly applying Coh-Metrix in SRS documents readability assessments cannot be permitted. Since the actual value of evaluated effectiveness is not high enough. In addition, all selected approaches are based on metrics of readability measures, but no semantic factors are blended in readability assessments. Hence studying more on human perception quantifying and adding semantic analysis in SRS documents readability assessment could be two research directions in future.

  • 2378.
    Chen, Rongrong
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Zhu, Min
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Birth Density Modeling in Multi-target Tracking Using the Gaussian Mixture PHD Filter2008Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    A recently established method for multi-target tracking which both estimates the time-varying number of targets and their states from a sequence of observation sets in the presence of data association uncertainty, detection uncertainty, noise and false alarms is the probability hypothesis density (PHD) recursion. The approach involves modeling the respective collections of targets and measurements as random finite sets and to propagate the posterior intensity, which is a first order statistic of the random finite set of targets, in time. A closed form solution to the PHD filter recursion for multi-target tracking is provided by the Gaussian Mixture Probability Hypothesis Density filter (GM-PHD filter), whose posterior intensity function is estimated by a sum of weighted Gaussian components, including means, weights and covariances that can be propagated analytically in time. Besides the GM-PHD filter algorithm implementation, choose the probability density function for representing target births in GM-PHD recursion and true target trajectory generation to get best tracking performance is a challenge and is the purpose of this thesis work. One reference to judge the performance of the algorithm is the target detection time, as given in this thesis.

  • 2379. Chen, S.H.
    et al.
    Wang, Tzuchiang
    Kao-Walter, Sharon
    A crack perpendicular to a bimaterial interface an interface in finite solid2003In: International Journal of Solids and Structures, ISSN 0020-7683 , Vol. 40, no 11, p. 2731-55Article in journal (Refereed)
    Abstract [en]

    The dislocation simulation method is used in this paper to derive the basic equations for a crack perpendicular to the bimaterial interface in a finite solid. The complete solutions to the problem, including the T stress and the stress intensity factors are obtained. The stress field characteristics are investigated in detail. It is found that when the crack is within a weaker material, the stress intensity factor is smaller than that in a homogeneous material and it decreases when the distance between the crack tip and interface decreases. When the crack is within a stiffer material, the stress intensity factor is larger than that in a homogeneous material and it increases when the distance between the crack tip and interface decreases. In both cases, the stress intensity factor will increase when the ratio of the size of a sample to the crack length decreases. A comparison of stress intensity factors between a finite problem and an infinite problem has been given also. The stress distribution ahead of the crack tip, which is near the interface, is shown in details and the T stress effect is considered.

  • 2380. Chen, S.H.
    et al.
    Wang, Tzuchiang
    Kao-Walter, Sharon
    Finite boundary effects in problem of a crack perpendicular to and terminating at a bimaterial interface2005In: Acta Mechanica Sinica, ISSN 0567-7718 (p)1614-3116(online), Vol. 21, no 1, p. 56-64Article in journal (Refereed)
    Abstract [en]

    The problem of a crack perpendicular to and terminating at an interface in bimaterial structure with finite boundaries is investigated. The dislocation simulation method and boundary collocation approach are used to derive and solve the basic equations.Two kinds of loading form are considered when the crack lies in a softer or a stiffer material, one is an ideal loading and the other one fits to the practical experiment loading. Complete solutions of the stress field including the T stress are obtained as well as the stress intensity factors. Influences of T stress on the stress field ahead of the crack tip are studied. Finite boundary effects on the stress intensity factors are emphasized. Comparisons with the probled presented by Chen et al. (int. J. Solids and Structure, 2003,40, 2731-2755) are discussed also.

  • 2381.
    Chen, Shajin
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Weibo's Role in Shaping Public Opinion and Political Participation in China2014Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    This thesis examines the role of microblogging in shaping public opinion and political participation in China with particular focus on the question of what sociopolitical implications and challenges that weibo phenomenon has brought to the Chinese society. I explore some of the prominent features of weibo for the role they plays in framing public sphere. Along with an in-depth study of two weibo cases, the results show that microblogging provide a unique platform for Chinese citizens to participate in civic engagement and to organize their collective opinions. The study also demonstrates that weibo has a significant impact on spurring social change. Further, weibo discourse encourages interaction between government and ordinary citizens, and it also changes traditional Chinese politics through enabling public political participation. However, the spread of rumors and network violence are some of the disadvantages inherent to the weibo phenomenon that should be of concern. More importantly, the analysis reveals that the initial reasons behind the weibo phenomenon were the long-term social conflicts and continuous information control by the state. Weibo certainly provides a remarkable platform for the freedom of speech but it should not be considered as a panacea for the social changes in China.

  • 2382.
    Chen, Xiaoran
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science.
    Image enhancement effect on the performance of convolutional neural networks2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context. Image enhancement algorithms can be used to enhance the visual effects of images in the field of human vision. So can image enhancement algorithms be used in the field of computer vision? The convolutional neural network, as the most powerful image classifier at present, has excellent performance in the field of image recognition. This paper explores whether image enhancement algorithms can be used to improve the performance of convolutional neural networks.

    Objectives. The purpose of this paper is to explore the effect of image enhancement algorithms on the performance of CNN models in deep learning and transfer learning, respectively. The article selected five different image enhancement algorithms, they are the contrast limited adaptive histogram equalization (CLAHE), the successive means of the quantization transform (SMQT), the adaptive gamma correction, the wavelet transform, and the Laplace operator.

    Methods. In this paper, experiments are used as research methods. Three groups of experiments are designed; they respectively explore whether the enhancement of grayscale images can improve the performance of CNN in deep learning, whether the enhancement of color images can improve the performance of CNN in deep learning and whether the enhancement of RGB images can improve the performance of CNN in transfer learning?Results. In the experiment, in deep learning, when training a complete CNN model, using the Laplace operator to enhance the gray image can improve the recall rate of CNN. However, the remaining image enhancement algorithms cannot improve the performance of CNN in both grayscale image datasets and color image datasets. In addition, in transfer learning, when fine-tuning the pre-trained CNN model, using contrast limited adaptive histogram equalization (CLAHE), successive means quantization transform (SMQT), Wavelet transform, and Laplace operator will reduce the performance of CNN.

    Conclusions. Experiments show that in deep learning, using image enhancement algorithms may improve CNN performance when training complete CNN models, but not all image enhancement algorithms can improve CNN performance; in transfer learning, when fine-tuning the pre- trained CNN model, image enhancement algorithms may reduce the performance of CNN.

  • 2383.
    Chen, Xin
    et al.
    Blekinge Institute of Technology, School of Engineering.
    Deng, Hongyu
    Blekinge Institute of Technology, School of Engineering.
    Wu, Zhong
    Blekinge Institute of Technology, School of Engineering.
    An Optimization Design for the Standard Manual Wheelchair2011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The standard manual wheelchair is commonly found in hospitals, rehabilitation centres, senior housing and airports for allowing patients, people with physical disabilities or elder people to move. In this thesis, a CAD model of the standard wheelchair is first obtained. Then, an optimization design is carried out based on this model. A sliding seat is designed to facilitate people moving by themselves from the wheelchair to any chair close by. On the other hand, a reclining backrest is also designed to make users feel more comfortable. Computer Simulations are performed to evaluate this design under static and dynamic conditions. A displacement range for the sliding seat in which the wheelchair will not overturn is determined. The optimization design shows significant improvements that can conveniently be introduced on the mechanical wheelchair in order to make it more useful and comfortable to the users.

  • 2384.
    Chen, Yousheng
    Blekinge Institute of Technology, School of Engineering.
    Simulation and Identification Techniques for Floating Structures2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The dynamic behaviour of floating structures is studied in this work. These types of structures are normally simplified into spring-mass systems where frequency dependent mass and damping is used to model the hydrodynamics. A method based on using digital filters to simulate the time response is tested in this work. The problem to identify added mass and added damping coefficients from measurement data is also examined. This is done by using the simulation model to generate time data. The predicted added mass and added damping can then be compared with the true coefficients and the identification method can be evaluated. Finally, an experimental system is studied and compared with simulation results.

  • 2385. Chen, Yuanfang
    et al.
    Li, Mingchu
    Shu, Lei
    Wang, L.
    Duong, Quang Trung
    Blekinge Institute of Technology, School of Computing.
    The scheme of mitigating the asymmetric links problem in wireless sensor networks2010Conference paper (Refereed)
    Abstract [en]

    This paper investigates the radio irregularity (RI) phenomenon and its impact on communication performance in wireless sensor networks (WSNs). Based on the theoretical analysis, we find that the RI phenomenon induces the asymmetric links problem. According to this discovery, we propose a novel HCT (Hop-count Correction Tree) scheme to handle this problem. HCT utilizes graph theoretical method to get a search tree and correct the hop count error that appears in the adjacent nodes. Practical results obtained from testbed experiments demonstrate that this solution can greatly improve localization accuracy in the presence of RI

  • 2386.
    Chen, Zixiang
    Blekinge Institute of Technology, School of Management.
    Billiard Club2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Billiard Club will provide a good billiard training and entertainment environment for the young beginners as well as mid-age fans of the cue-shot games in Karlskrona. There would also be some Asian style Fast food provided in the Club.

  • 2387.
    Chender, Isabel
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Strategic Sustainable Development.
    Viggiani, Raquel Luna
    Blekinge Institute of Technology, Faculty of Engineering, Department of Strategic Sustainable Development.
    Patarroyo, Zulma
    Blekinge Institute of Technology, Faculty of Engineering, Department of Strategic Sustainable Development.
    The Role of Rural Development Interventions in Creating a Sustainable Society2014Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The inter-related social and ecological facets of global sustainability imply that the way society develops will impact the environment. Development presents complex, multifaceted challenges. Interventions in the developing world in the form of projects created by the agencies, organizations and agents of the international development community increasingly appreciate and seek to address these challenges. Yet, to do so effectively, interventions need to shift from fragmented, sector-specific approaches based on formal data reports to approaches that anticipate, adapt, transform, and learn. This research aims to complement and support the practical and theoretical knowledge of rural development agents with insights from practitioners using approaches that consider complexity in other fields, in order to explore how development interventions could play a role in moving society toward sustainability. A prototype guide for rural development interventions synthesizes results gathered from interviews with rural development agents within Latin America and learning experience designers into three levels: system, interaction, and personal. The Framework for Strategic Sustainable Development (FSSD) provides a systems perspective and unifying definition of sustainability. The interaction level presents key recommendations, rationale, and methods for action, and the personal level presents reflection questions. This research hopes to inspire mutual learning between development actors and communities.

  • 2388.
    Cheng, Chow Kian
    et al.
    Blekinge Institute of Technology, School of Computing.
    Permadi, Rahadian Bayu
    Blekinge Institute of Technology, School of Computing.
    Towards an Evaluation Framework for Software Process Improvement2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Software has gained an essential role in our daily life in the last decades. This condition demands high quality software. To produce high quality software many practitioners and researchers put more attention on the software development process. Large investments are poured to improve the software development process. Software Process Improvement (SPI) is a research area which is aimed to address the assessment and improvement issues in the software development process. One of the most important aspects in software process improvement is to measure the results gained from the embarked process change. Without measuring the results, it is hard to tell whether the goals have been achieved or not. However, measurement for software process improvement is not a trivial task. Furthermore, there is no common systematic methodology that can be used to help measuring the performance of software process improvement initiatives. This thesis is intended to provide basic key concepts for the effective measurement and evaluation of the outcome of software process improvement. A major part of this thesis presents the systematic review in evaluating the outcome of software process improvement. The systematic review is aimed at the identification of the major issues in software process improvement evaluation and to gather the requirements for a software process improvement measurement and evaluation framework. Based on the results of the systematic review, a measurement and evaluation model is formulated. The objective of the model is to provide the groundwork for a software process improvement measurement and evaluation framework. The model is deemed to be applicable in a broad spectrum of scenarios by providing concepts that are independent from specific SPI initiatives.

  • 2389.
    Cheng, Zeng
    Blekinge Institute of Technology, School of Planning and Media Design.
    Urban Sprawl: how to prevent from urbanization to counterurbanization - the Research and Thinking of Compact City and Satellite City2010Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Sprawl seems an inevitable phenomenon because of the rapid expansion in urban area. It has some negative consequences, such as long transport distance to work, high car dependence and inadequate facilities. Recently, it pointed as causing a lot of urban problems and the situation has been worsening. This thesis asks the question: could there be a conscious way to prevent this issue? To deal with it, this thesis firstly conducts an intensive study about theories of compact city and satellite city. In the second part, in order to investigate how those theories are reflected and implemented in real examples, this thesis analyzes two cases and discusses about how urban sprawl happened in London and Shanghai as well as to what extent theories were served in these two cities. The investigation produces some results related to the process of urbanization, common actions which authorities would take towards it, and some highlights in the pre-experience. So when facing with urban sprawl, the measure might be dealt with it in a more conscious way.

  • 2390.
    Chengqi, Li
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Blekinge Institute of Technology, Sweden.
    PSS for Functional Offering of Automotive Fixtures using Knowledge Enabled Engineering Techniques2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the automotive industry, the configuration of the fixture setups is an important process before production begins. However, the process is time-consuming and repetitive, which means that it takes a vast workload and tedious manual work, and relies on experts. This issue consumes a great deal of engineers’ time, wastes companies’ resources, and hence lowers the efficiency of relevant companies.

    The purpose of this study is to address the problem in how to find a way to make the current fixture-setup configuration work more effectively. Through the theory of knowledge-based engineering (KBE) and with the help of 3D-solid Computer Aided Design (CAD) and Object Oriented Programming (OOP), a model is designed to help automate the process of fixture configuration. The goal of the model is to help the companies improve their configuration efficiency to create more value to the company and society.

    This thesis explores how to implement KBE with 3D-CAD and OOP to reach the final purpose of the study; explain to you what is KBE and why to choose KBE to conduct. By taking the KBE-conceptualized model as a carrier, it also explores the practicability of integration of KBE, 3D-CAD, and OOP. This thesis reports on the model which shows the Knowledge-based element of each action as well as a SWOT analysis of the entire model.

  • 2391.
    Chengzhong, Jia
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Analysis of solar cells in different situations2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 2392.
    Chennamsetty, Harish
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Experimentation in Global Software Engineering2015Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Context: Software engineering researchers are guided by research principles to conduct any type of research. Though, there are many guidelines to detail how a particular research method can be applied, there is always a necessity to continue and to improve the existing empirical research strategies. The context of this thesis is to address guidelines for conducting controlled experiments in Global Software Engineering (GSE). With this thesis, the state-of-the-art of conducting experiments in GSE research has been explored. Objectives: The goal of this thesis is to analyze the existing experiments in GSE research. Research problems addressed with GSE experiments and the state-of-the-art of overall GSE experiment design need to be analyzed. Appropriate guidelines should be drawn in order to provide strategies to future GSE researchers in mitigating or solving GSE specific experimentation challenges. Methods: A systematic literature review (SLR) is conducted to review all the GSE experiments that are found in the literature. The search process was done on 6 databases. A specific search and quality assessment criterion is used to select these GSE experiments. Furthermore, scientific interviews are conducted with GSE research experts to evaluate a set of guidelines (thesis author’s recommendations) that address the challenges when conducting GSE experiments. Thematic analysis has been performed to analyze the evaluation results and to further improve or implement any suggestions given by the interviewees. Conclusions: The results obtained from the SLR have provided a chance to understand the state-of-the-art and to analyze the challenges or problems when conducting controlled experiments in GSE. The challenges that are identified in GSE controlled experiments are found to be with experiment study-setting, involving subjects and addressing GSE relevant threats to validity in a GSE experiments. 9 guidelines are framed, with each guideline addressing a specific challenge. The final guidelines (that resulted after interviews) provide effective recommendations to GSE researchers when conducting controlled experiments.

  • 2393.
    Cherif, Redha
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Software Process Simulation Modelling: A Multi Agent-Based Simulation Approach2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    In this research we present one of the first actual applications of Multi Agent-Based Simulation (MABS) to the field of software process simulation modelling (SPSM). Although a few previous applications were attempted, we explain in our literature review how these failed to take full advantage of the agency paradigm. Our research resulted in a model of the software development process that integrates performance, cognition and artefact quality, for which we built a common simulation framework to implement and run MABS and System Dynamics (SD) simulators upon the same integrated models. Although it is not possible to fully verify and validate implementations and models like ours, we used a number of verification and validation techniques to increase our confidence in these. Our work is also quite unique in that it compares MABS to SD in the context of SPSM. Here, we uncovered quite interesting properties of each simulation approach and how MABS, for example, is "risk averse" when compared to SD. In our discussion section we also present a number of lessons learned regarding the two simulation paradigms as well as various shortcomings in the models we adopted and our own.

  • 2394. Cherif, Redha
    et al.
    Davidsson, Paul
    Blekinge Institute of Technology, School of Computing.
    Software Development Process Simulation: Multi Agent-Based Simulation versus System Dynamics2009Conference paper (Refereed)
    Abstract [en]

    We present one of the first actual applications of Multi Agent-Based Simulation (MABS) to the field of software process simulation modelling (SPSM). Although there are some recent attempts to do this, we argue that these fail to take full advantage of the agency paradigm. Our model of the software development process integrates individual-level performance, cognition and artefact quality models in a common simulation framework. In addition, this framework allows the implementation of both MABS and System Dynamics (SD) simulators using the same basic models. As SD is the dominating approach within SPSM, we are able to make relevant and unique comparisons between it and MABS. This enabled us to uncover quite interesting properties of these approaches, e.g., that MABS re-flects the problem domain more realistically than SD.

  • 2395. Cherif, Redha
    et al.
    Davidsson, Paul
    Software Development Process Simulation: Multi Agent-Based Simulation versus System Dynamics2010In: Multi Agent Based Simulation X, Lecture Notes in Computer Science, Springer , 2010Chapter in book (Refereed)
    Abstract [en]

    We present one of the first actual applications of Multi Agent-Based Simulation (MABS) to the field of software process simulation modelling (SPSM). Although there are some recent attempts to do this, we argue that these fail to take full advantage of the agency paradigm. Our model of the software development process integrates individual-level performance, cognition and ar- tefact quality models in a common simulation framework. In addition, this framework allows the implementation of both MABS and System Dynamics (SD) simulators using the same basic models. As SD is the dominating ap- proach within SPSM, we are able to make relevant and unique comparisons be- tween it and MABS. This enabled us to uncover quite interesting properties of these approaches, e.g., that MABS reflects the problem domain more realisti- cally than SD.

  • 2396.
    Cherukula, Pardhasaradhi Reddy
    Blekinge Institute of Technology, School of Engineering.
    Close talk Speech enhancement in Linear Microphone array for Laptop application2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Now a day’s communication through laptops is drastically increasing in numerous fields. During the communication between person to person through laptops the speech signals is contaminated by the other speech interference signals. In order to enhance the desired speech signal from the noisy environment there are many algorithms are proposed in speech signal processing. This thesis work studies about the suppression of interference signals produced by the surrounding environments for the close talk applications of laptop. In this thesis work uses the three microphones of linearly equi spaced in 3D-co-ordinate system. The speech enhancement algorithms implemented in microphone array were wiener beamforming, Generalized sidelobe canceller using LMS and N-LMS. In order to enhance the desired speech signal with good quality, compares the result of each algorithm using quality metrics like SNR, SNRI and PESQ. The implementation and validation of the algorithms is simulated in Matlab. The quality metrics taken is SNRI and PESQ. In PESQ the output signal is compared with the original clean speech signal and gives the quality measure of the output signal. The SNR tests were conducted for the different input SNR values according to 0dB, 5dB, 10dB, 15dB, 20dB and 25dB. The Simulation result shows that the wiener beamformer effective noise suppression i.e SNRI is 27.9869dB and maintains the speech quality i.e PESQ measurement is 1.459.The effective noise suppression i.e SNRI of the GSC using LMS is 6.0206 dB higher than the wiener beamformer and speech quality is slightly incremental. Comparing the results of GSC using LMS and N-LMS algorithms, The GSC using N-LMS gives the effective noise suppression 3.48dB higher than the GSC using LMS and speech quality i.e PESQ is slightly decreases.

  • 2397.
    Chervyakov, Anatoly
    Blekinge Institute of Technology, Department of Software Engineering and Computer Science.
    Simulation-based evaluation of berth allocation policies of container terminals2003Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The aim of this investigation is to test and verify a hypothesis concerning policies for berth allocation to ships in a container terminal. The chosen domain is a rich research area where simulation could be used. Because of the high amount of variables involved and demand for optimal usage of available resources management of a container terminal is a great challenge.

  • 2398.
    Chester, Ronan
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Woofter, Jennifer
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Non-Financial Disclosure and Strategic Planning: Sustainability Reporting for Good Corporate Governance2005Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    A sustainability report is a tool to help organizations monitor and communicate economic, environmental, and social performance. A corporate strategic planning model is a tool that guides businesses through decision-making processes for sustainable competitive advantage and long-term economic success. While both tools can be used to move a company towards sustainability, the processes are usually not closely integrated. This project explores a closer integration of sustainability reporting and strategic planning for improved corporate governance and strategic sustainable development. We scrutinize the 2002 Global Reporting Initiative Sustainability Reporting Guidelines against a scientific principle definition of sustainability, pointing out current shortcomings and suggesting opportunities for improvement. An enhanced sustainability reporting model is proposed followed by an exploration of how this reporting model can bring value to the corporate strategic planning process.

  • 2399.
    CHETACHI, UMUNNA CHRISTIAN CHEZZ
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Security and Performance Analysis of Topology-Based Intrusion Detection System in Ad Hoc Networks2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    As Wireless ad-hoc Networks are becoming an increasingly emerging technology taking a centre stage in exciting research areas which has attracted many research attentions in communication systems, the need for efficient intrusion detection techniques to enhance network security and privacy has gained significant prominence. Intrusion detection systems(IDS) in ad- hoc networks provides an effective method to improve the security, energy efficiency of transmission nodes allowing better spatial reuse of the wireless channel and control over network resources in order to optimize node security and the transmit power thereby maintaining network connectivity. However these global properties have been falsified due to lack of appropriate intrusion detection system leading to severe network failures which is the bane of next generation ad-hoc networks. In this thesis, we investigate few wireless ad-hoc security attacks and vulnerabilities relative to topology control schemes and evaluate their performance under hostile environments. We propose a novel Distributed Intrusion Detection System (DIDS) that incorporates rule- based cluster topology relevant to both Wireless sensor networks (WSNs) and Mobile ad hoc networks (MANETs) to determine their security/performance in application- specific environments. Our DIDS draws inferences of intrusion by comparing anomalous patterns from packet traces of transmit and receive signal powers, ratio of packet arrival rates and anomaly in radio receiver packet power thresholds using buffer window count. Hence we evaluate our intrusion detection mechanism on a jammer attack and observe the effect on the network throughput. Our approach is simulated using the OPNET® simulator. Simulation results show that the detection capabilities of our scheme under a denial of service (DoS) (jammer) attack, increases the bit error rates, increase in transmit delay responses and considerable decrease in both the signal to noise powers and the average network throughput due to the presence of jammer attack which forms the baseline for our analysis required to maintain energy efficiency and improve security in ad hoc network.

  • 2400. Chevul, Stefan
    On Application-Perceived Quality of Service in Wireless Networks2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wireless and Mobile Internet have changed the way people and businesses operate. Communication from any Internet access point, including wireless networks such as UMTS, GPRS or WLAN has enabled organizations to have a mobile workforce. However, networked applications such as web, email, streaming multimedia etc. rely upon the ability of timely data delivery. The achievable throughput is a quality measure for the very task of a communication system, which is to transport data in time. Throughput is thus one of the most essential enablers for networked applications. While in general, throughput is defined on network or transport level, the application-perceived throughput reflects the Quality of Service from the viewpoints of the application and user. The focus of the thesis is on the influence of the network on the applicationperceived Quality of Service and thus the user perceived experience. An analysis of application based active measurements mimicking the needs of streaming applications is presented. The results reveal clear influence of the network on the application-perceived Quality of Service seen from variations of application-perceived throughput on small time scales. Results also indicate that applications have to cope with considerably large jitter when trying to use the nominal throughputs. It was observed that the GPRS network had considerable problems in delivering packets in the downstream direction even when the nominal capacity of the link was not reached. Finally, the thesis discusses the suitability of wireless networks for different mobile services, since the influence of the network on the application-perceived Quality of Service is of great significance when it comes to customer satisfaction. Therefore, application-perceived Quality of Service in wireless networks must also be considered by the mobile application programmer during the application development.

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