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  • 251.
    Pitoňák, Martin
    et al.
    University of West Bohemia, NTIS – New Technologies for the Information Society, Faculty of Applied Sciences, Technická 8, 306 14 Plzeň, Czech Republic (CZE).
    Novák, Pavel
    University of West Bohemia, NTIS – New Technologies for the Information Society, Faculty of Applied Sciences, Technická 8, 306 14 Plzeň, Czech Republic (CZE).
    Eshagh, Mehdi
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Tenzer, Robert
    The Hong Kong Polytechnic University, Department of Land Surveying and Geo-Informatics, 181 Chatham Road South, Hung Hom, Kowloon, Hong Kong (HKG).
    Šprlák, Michal
    University of West Bohemia, NTIS – New Technologies for the Information Society, Faculty of Applied Sciences, Technická 8, 306 14 Plzeň, Czech Republic (CZE).
    Downward continuation of gravitational field quantities to an irregular surface by spectral weighting2020In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 94, no 7, article id 62Article in journal (Refereed)
    Abstract [en]

    In geophysical and geodetic studies, gravity inversion is typically performed such that observed gravity values are first continued downward onto a regular (planar, spherical or spheroidal) surface by solving an inverse integral transform, which originates from a classical solution to the first boundary-value problem in potential theory. A typical example is continuing gravity observed at the topographic surface down to the mean sea level (geoid). Nowadays, gravity-dedicated satellite missions and aerial gravimetry provide gravity data above the topographic surface in addition to classical terrestrial gravity observations. For specific purposes (such as gravity data combination and validation, or quasigeoid determination), satellite and aerial gravity observations have to be continued to the irregular topographic surface. In this study, we address this issue by formulating a functional model for a spectral downward continuation of selected gravitational field quantities to an irregular topographic surface. Moreover, we generalize this functional model to allow for transformation between different types of gravitational field quantities. In particular, we derive spectral weights for estimation of the disturbing potential or disturbing/anomalous gravity at the Earth’s surface by combining the first-, second- and third-order radial gradients of the disturbing potential (disturbing gradients). The correctness of the developed combined spectral estimator is verified in a closed-loop test based on synthetic satellite disturbing gradients. The combined spectral estimator is applied to simulated satellite disturbing gradients polluted by a realistic Gaussian noise. Results of the numerical experiments show that the combined spectral estimator puts the highest importance on the least polluted disturbing gradient, while the contribution of the least accurate disturbing gradient is negligible. An important advantage of this spectral combination method is that no matrix inversion with numerical instabilities requiring regularization is needed.

  • 252.
    Rathnayake, Samurdhika
    et al.
    Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, 181 Chatham Road South, Hung Hom, Kowloon, (HKG).
    Tenzer, Robert
    Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, 181 Chatham Road South, Hung Hom, Kowloon (HKG).
    Chen, Wenjin
    School of Geomatics Science and Technology, Nanjing Tech University, 30 New Mofan Road, 210009, Nanjing (CHN).
    Eshagh, Mehdi
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Pitonak, Martin
    Department of Geomatics, Faculty of Applied Sciences, University of West, Technicka 8, 301 00, Pilsen (CZE).
    Comparison of Different Methods for a Moho Modeling Under Oceans and Marginal Seas: A Case Study for the Indian Ocean2021In: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 42, no 4, p. 839-897Article in journal (Refereed)
    Abstract [en]

    Since marine seismic studies are relatively sparse and unevenly distributed, detailed tomographic images of the Moho geometry under large parts of the world’s oceans and marginal seas are not yet available. Marine gravity data is, therefore, often used to detect the Moho depth in these regions. Alternatively, Airy’s isostatic theory can be applied for this purpose. In this study, we compare different isostatic and gravimetric methods for a Moho recovery under the oceanic crust and continental margins, particularly focusing on a numerical performance of Airy, Vening Meinesz-Moritz (VMM), direct gravity inversion, and generalized (for the Earth’s spherical approximation) Parker-Oldenburg methods. Numerical experiments are conducted to estimate the Moho depth beneath the Indian Ocean. Results reveal that, among these investigated methods, the VMM model is probably the most suitable for a gravimetric Moho recovery beneath the oceanic crust and continental margins, when taking into consideration the lithospheric mantle density information. This method could to some extent model realistically a Moho geometry beneath mid-oceanic spreading ridges, oceanic subductions, most of oceanic volcanic formations, and marine sediment deposits. Nonetheless, this model still cannot fully reproduce a gradual Moho deepening caused by a conductive cooling and a subsequent isostatic rebalance of the oceanic lithosphere, which can functionally be described by a Moho deepening with the increasing ocean-floor age. Results also indicate that the Airy method typically overestimates the Moho depth under oceanic volcanic formations, while the direct gravity inversion and generalized Parker-Oldenburg methods could not reproduce more detailed features in the Moho geometry. Since Pratt’s theory better describes a large-scale isostatic mechanism of the oceanic lithosphere by means of compensation density variations, but does not account for additional changes in compensation depth (i.e., Moho depth) that are caused by these density changes, we tested a possibility of combining Pratt and Airy’s isostatic theories in order to estimate the Moho depth under the oceanic crust. Even this combined model cannot fully reproduce a gradual Moho deepening with the increasing ocean-floor age.

  • 253.
    Rathnayake, Samurdhika
    et al.
    Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
    Tenzer, Robert
    Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
    Eshagh, Mehdi
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Pitoňák, Martin
    New Technologies for the Information Society, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic.
    Gravity Maps of the Lithospheric Structure Beneath the Indian Ocean2019In: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 40, no 5, p. 1055-1093Article in journal (Refereed)
    Abstract [en]

    The lithospheric structure beneath the Indian Ocean is probably the most complicated, but at the same time, the least understood among world's oceans. Results of tomographic, geochemical, magnetic and other surveys provide the evidence of its complex geological history. Seismic surveys have been a primary source of information about the lithospheric structure beneath the Indian Ocean, but these experiments are mainly concentrated at locations of a high geophysical interest. Marine gravity data obtained from processing the satellite altimetry measurements, on the other hand, deliver a detailed image of the whole seafloor relief, advancing further the knowledge about its formation, tectonism and volcanism. In this study, we use gravitational, bathymetric, marine sediment and lithospheric density structure data to compile the Bouguer and mantle gravity maps. We then use both gravity maps to interpret the lithospheric structure beneath the Indian Ocean. The Bouguer gravity map reveals major tectonic and volcanic features that are spatially correlated with crustal thickness variations. The mantle gravity map exhibits mainly a thermal signature of the lithospheric mantle. Gravity lows in this gravity map mark distinctively active oceanic divergent tectonic margins along the Central, Southeast and Southwest Indian Ridges including also the Carlsberg Ridge. Gravity lows extend along the Red Sea-Gulf of Aden and East African Rift Systems, confirming a connection between mid-oceanic spreading ridges (in the Indian Ocean) and continental rift systems (in East Africa). The combined interpretation of the Bouguer and mantle gravity maps confirms a non-collisional origin of mountain ranges along continental rift systems in East Africa. The evidence of a southern extension of the East African Rift System and its link with the Southwest Indian Ridge in the mantle gravity map is absent. Similarly, the ongoing breakup of the composite Indo-Australian plate is not manifested. A missing thermal signature in the mantle gravity map at these two locations is explained by the fact that the southern Nubian-Somalian plate boundary (i.e., the Lwandle plate) and the Indo-Australian plate boundary (i.e., the Capricorn plate) are diffuse zones of convergence, characterized by low deformation and seismicity due to very slow rates of relative motions accommodated across these boundaries. The clear manifestation of the thermal signature of intraplate hot spots in the mantle gravity map is also absent. This finding agrees with the evidence from direct heat flow measurements that do not indicate the presence of a significant positive temperature anomaly compared to the oceanic lithosphere of a similar age. © 2019, Springer Nature B.V.

  • 254.
    Regnér, Susanna
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Wasberg, Johanna
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Implementering av stadsgrönska och ekosystemtjänster i urbana miljöer: från start till mål2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study investigates the process chain for implementing urban greenery and ecosystem services in urban environments. This is done from the time the assignment is given by the government to the relevant authority, the continued work there, on to the work out at the municipalities and other relevant actors.

    Ecosystem services are the benefits that we humans receive indirectly and directly by nature. We are dependent on the ecosystems continuing to produce services that are vital to human health, well-being and for our entire existence. Commonly work and careful use of our resources are needed to ensure ecosystem services. Preserving, developing and innovating urban and green areas can result in great social benefits and integrating ecosystem services into physical planning is a step in the right direction.

    Two stagegoals were developed in 2018, where one goal means that the municipalities should have access to a developed method regarding the integration of urban greenery and ecosystem services in urban environments by 2020. The second goal means that a majority of the municipalities must use and integrate urban greenery and ecosystem services by 2025 at the latest, in planning, construction and management.

    The study result is based on how far the municipalities have come to work on the two stagegoals, as well as Boverkets work behind the developed method and with reaching out with the information to the municipalities and other concerned. The result also includes the work in conjunction with Naturvårdsverket when the assignment would take place in collaboration with them. This has been done with both qualitative and quantitative methods, through interviews and questionnaires.

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  • 255.
    Rossing, Carl Adrian
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Carlson, Thomas
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    IPSec med NAT: Påverkan på datamängd och latens2020Independent thesis Basic level (degree of Bachelor), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This project was aiming to research the potential impact that IPSec, combined with using NAT to translate addresses, could have on both the amount of data being sent and latency. By setting up four network topologies in a lab environment with different configurations and conducting two specific tests in each topology, the relevant data that was needed to form conclusions regarding this was obtained.

    The two tests that was conducted were:

    1. Sending 5000 pings from one host to another host across the network.

    2. Transferring 1 GB of data from one host to another host across the network.

    No evidence was found that showed that latency is affected by using both IPSec and NAT, but it does have an impact on the size of individual packets. By using both protocols, an additional UDP header including 8 bytes of data is added onto each packet, which in turn requires more overhead data to be sent in total. The additional overhead can cause issues with MTU sizes and fragmentation if not handled correctly, which leads to more overhead and more processor usage.

  • 256.
    Rutgersson, Max
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Jaderi, Karim
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Cloud Gaming: Framtiden inom spelindustrin eller ej?2020Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    Målet är att genomföra tester för att avgöra om "Cloud Gaming" håller en tillräckligt hög standard för att ersätta lagrad gaming. Detta görs genom att ha noggranna tester för streamingservices som Playstation Now samt Geforce Now och kollar om tjänsten verkligen är användbar på olika mängder bandbredd, inklusive deras officiella minimikrav och sedan jämföra detta med vad bandbreddstandarden är för resten av världen. Det som resulterade utifrån detta var att världen faktiskt inte var redo för kraven som streamad gaming hade på folket, men även att även streamingtjänster som tex Playstation Now samt Geforce Now inte heller är redo för att bli en standard runtom i världen när det gäller spel.

  • 257.
    Ryberg, Anders
    et al.
    University West, Department of Engineering Science.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production Systems.
    Eriksson, Kenneth
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Camera Modelling and Calibration - with Applications2008In: Computer Vision / [ed] Zhihui, X., Vienna: I-Tech Education and Publishing , 2008, p. 303-332Chapter in book (Other academic)
  • 258.
    Saberi, Azim
    et al.
    Department of RS and GIS, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz (IRN).
    Kabolizadeh, Mostafa
    Department of RS and GIS, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz (IRN).
    Rangzan, Kazem
    Department of RS and GIS, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz (IRN).
    Abrehdary, Majid
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Accuracy assessment and improvement of SRTM, ASTER, FABDEM, and MERIT DEMs by polynomial and optimization algorithm: A case study (Khuzestan Province, Iran)2023In: Open Geosciences, ISSN 2391-5447, Vol. 15, no 1, article id 20220455Article in journal (Refereed)
    Abstract [en]

    Satellite digital elevation models (DEMs) are used for decision-making in various fields. Therefore, evaluating and improving vertical accuracy of DEM can increase the quality of end products. This article aimed to increase the vertical accuracy of most popular satellite DEMs (i.e., the ASTER, Shuttle Radar Topography Mission [SRTM], Forest And Buildings removed Copernicus DEM [FABDEM], and Multi-Error-Removed Improved-Terrain [MERIT]) using the particle swarm optimization (PSO) algorithm. For this purpose, at first, the vertical error of DEMs was estimated via ground truth data. Next, a second-order polynomial was applied to model the vertical error in the study area. To select the polynomial with the highest accuracy, employed for vertical error modeling, the coefficients of the polynomial have been optimized using the PSO algorithm. Finally, the efficiency of the proposed algorithm has been evaluated by other ground truth data and in situ observations. The results show that the mean absolute error (MAE) of SRTM DEM is 4.83 m while this factor for ASTER DEM is 5.35 m, for FABDEM is 4.28, and for MERIT is 3.87. The obtained results indicated that the proposed model could improve the MAE of vertical accuracy of SRTM, ASTER, FABDEM, and MERIT DEMs to 0.83, 0.51, 0.37, and 0.29 m, respectively. 

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  • 259.
    Samuelsson, Alice
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Dahlin, Elliott
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    En undersökning om mottagligheten av nätfiskeattacker hos HV:s användare2021Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report reviews the basics of phishing and examines the susceptibility on phishing attacks of the Engineering department at University West.

    The report contains three different simulations of common phishing attacks and presents the data on how well the user in each institution handles this.

    The results show that 16% of users targeted compromised their data in the attacksimulation.

  • 260.
    Sandberg, Freddy
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Hellman, Robert
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Parallel Computing: Performance of a clustered Raspberry Pi environment vs desktop processors2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study wanted to find out if a company was spending unnecessary recourses on its equipment by installing big servers when they would actually manage just fine on a cluster of Raspberry Pis. Raspberry Pis performance have never been powerful enough to be implemented in a company network, but with the latest generation that was changed. The authors then wanted to know if the technology was ready to be used in a production network.

    The equipment used in this study comprised of a total of nine Raspberry Pi 4s and a selection of different processors under different kinds of loads. The different processors had been given the task of rendering the classic BMW-render in Blender Render, after which they’ve been investigating how many prime numbers they could find between 2 and one million. This was done using both on single thread, and multithread. After this, compared how long it took for the different processors to complete the task. The cluster proved to be slower than expected. The quickest processor in the study completed the rendering of a frame in one third of the time it took for the cluster to do the same. When benchmarking the clusters ability to calculate primes, it took about six times as long as the Ryzen 9 when the AMD had access to all its threads.

    To test the clusters response intensive performance a webserver application was installed and then stress tested with the help of three other stronger computers. One of the machines that was stress testing also collected the response time to determine how much impact that was made. With Apache2 installed the cluster stopped responding after 500 open sockets. With NGINX installed the impact was not big enough to notice any difference in the performance, no matter how long and strong the test ran for.

  • 261.
    Scotti, Americo
    et al.
    University West, Department of Engineering Science, Division of Welding Technology. Center for Research and Development of Welding Processes (Laprosolda), Federal University of Uberlandia (UFU), Uberlândia, MG (BRA).
    Batista, Márcio Andrade
    Department of Food Engineering, Federal University of Mato Grosso (UFMT), Cuiabá (BRA).
    Eshagh, Mehdi
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Inaccuracy in arc power calculation through a product of voltage and current averages2022In: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 44, no 1, p. 1-9, article id 11Article in journal (Other academic)
    Abstract [en]

    Power is an indirect measurand, determined by processing voltage and current analogue signals through calculations. Using arc welding as a case study, the objective of this work was to bring up subsidies for power calculation. Based on the defnitions of correlation and covariance in statistics, a mathematical demonstration was developed to point out the diference between the product of two averages (e.g. P=UxI) and the average of the products (e.g. P=(UxI). Complementarily, a brief on U and I waveform distortion sources were discussed, emphasising the diference between signal standard deviations and measurement errors. It was demonstrated that the product of two averages is not the same as the average of the products, unless in specifc conditions (when the variables are fully correlated). It was concluded that the statistical correlation can easily fag the interrelation, but if assisted by covariance, these statistics quantify the inaccuracy between approaches. Finally, although the statistics' determination is easy to implement, it is proposed that power should always be calculated as the average of the instantaneous U and I products. It is also proposed that measurement error sources should be observed and mitigated, since they predictably interfere in power calculation accuracy.

  • 262.
    Seif, M. R.
    et al.
    Arak University of Technology, Department of Surveying Engineering, Arak, Iran.
    Sharifi, M. A.
    University of Tehran, School of Surveying and Geospatial Engineering, College of Engineering, Tehran, Iran.
    Eshagh, Mehdi
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Polynomial approximation for fast generation of associated Legendre functions2018In: Acta Geodaetica et Geophysica, ISSN 2213-5812, Vol. 53, no 2, p. 275-293Article in journal (Refereed)
    Abstract [en]

    Today high-speed computers have simplified many computational problems, but fast techniques and algorithms are still relevant. In this study, the Hermitian polynomial approximation is used for fast evaluation of the associated Legendre functions (ALFs). It has lots of applications in geodesy and geophysics. This method approximates the ALFs instead of computing them by recursive formulae and generate them several times faster. The approximated ALFs by the Newtonian polynomials are compared with Hermitian ones and their differences are discussed. Here, this approach is applied for computing a global geoid model point-wise from EGM08 to degree and order 2160 and in propagating the orbit of a low Earth orbiting satellite. Our numerical results show that the CPU-time decreases at least two times for orbit propagation, and five times for geoid computation comparing to the case where recursive formulae for generation of ALFs are used. The approximation error in the orbit computation is at a sub-millimeter level over two weeks and that the computed geoid 0.01 mm, with a maximum of 1 mm

  • 263.
    Shabo, Elias
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    El-Boustany, Georges
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    10 år med expropriationslagens nya ersättningsregler2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Society is constantly evolving. For this to occur, land can sometimes be required through eminent domains. The Expropriation Act (SFS 1972:719) specifies who can expropriate and for what purpose. The Expropriation Act went through a reform on the 1st of August 2010 and was the first reform since the introduction of the law. One of the purposes of the reform was to strengthen the rights of private property owning. The most significant change of the law was in the fourth chapter. The third paragraph (rule of presumption) was abolished and new compensation provisions were introduced to the chapter. The newer remuneration supplement was based on compensation for the land access plus an additional 25 percent. The government considered that the changes in the reform would contribute to a stronger ownership and the thesis aims, among other things, to investigate whether the ownership has been strengthened and how the reform has affected practitioners of the eminent domains.The study focuses mainly on analyzing the two biggest changes in the reform based on an interview study in which respondent's opinions shaped the results of the survey. Selections of interviewees were based on knowledge and expertise within the Expropriation Act. Eight representatives were mainly chosen to be interviewed as they somehow apply the Expropriation Act in their daily work. After processing the interviews that were held, conclusions were drawn about the introduction of the remuneration supplement and the abolition of the presumption rule.The compensation provisions that applies today have strengthened the individual ownership from an economic perspective. The municipalities that were interviewed expressed that it was reasonable that property owners in present time receive an extra 25 percent caused by the effects of the eminent domain that occurs. Although the remuneration supplement and the rule of presumption were forecasted to affect the municipalities´ financial position for land access, implications show that there were no significant inconveniences due to the reform.

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  • 264.
    Shahzad, .
    et al.
    Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, (KOR).
    Ali, Rashid
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Haider, Amir
    Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, (KOR).
    Kim, Hyung Seok
    Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, (KOR).
    RS-RLNC: A Reinforcement Learning-Based Selective Random Linear Network Coding Framework for Tactile Internet2023In: IEEE Access, E-ISSN 2169-3536, Vol. 11, p. 141277-141288Article in journal (Refereed)
    Abstract [en]

    Tactile Internet (TI) has very stringent networking requirements and the transport layer plays a crucial role in meeting these requirements. However, the transport layer has several inherent limitations (e.g., bufferbloat, incast issue, and head of line blocking) due to which the performance of the current transport layer solutions is not optimal. We advocate replacing the “store-and-forward” strategy in transport layer solutions with the “compute-and-forward” strategy. One way to implement the “compute-and-forward” strategy is random linear network coding (RLNC). This paper proposes a learning-based RLNC framework called RS-RLNC that utilizes network and receiver feedback to optimally select between block-RLNC and sliding-RLNC to improve overall network performance. We present a simulation-based performance evaluation of current transport layer solutions against the state-of-the-art RLNC and RS-RLNC in terms of throughput, latency, and decoding complexity. Delay is reduced by a factor of 8.5% and decoding complexity is improved up to 20% compared to the state-of-the-art. Simulation results indicate that RS-RLNC has the potential to meet the stringent requirements of TI applications. Additionally, we present three future directions outlining the evolution of RS-RLNC to enhance the transport layer for TI compatibility.

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  • 265.
    Sjöberg, Lars
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Arne Bjerhammar- a personal summary of his academic deeds2021In: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 11, no 1, p. 1-6Article in journal (Other academic)
    Abstract [en]

    Arne Bjerhammar is well known worldwide mainly for his research in physical geodesy but also for introducing a new matrix algebra with generalized inverses applied in geodetic adjustment. Less known are his developments in geodetic engineering and contributions to satellite and relativistic geodesy as well as studies on the relation between the Fennoscandia land uplift and the regional gravity low. Most likely part of his research has contributed to worldwide political relaxation during the cold war, which deed was honored by a certificate of achievement awarded by the Department of Research of the US army as well as the North Star Order by the King of Sweden. Arne Bjerhammar’s pioneer scientific production, in particular on a world geodetic system, towards what would become GPS, as well as relativistic geodesy, is still of great interest among the worldwide geodetic community, while the memories and spirit along his outstanding academic deeds have more or less fainted away from his home university (KTH) only a decade after he passed away.

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  • 266.
    Sjöberg, Lars
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Geoid model validation and topographic bias2022In: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 12, no 1, p. 38-41Article in journal (Refereed)
    Abstract [en]

    Recently a number of geoid campaigns were performed to verify different types of geoid and quasigeoid modeling techniques. Typically, GNSS-leveling was employed as an independent method, but in some cases zenith camera astronomic deflection data were also used in astrogeodetic determinations of the geoid and/or quasigeoid. However, due to the uncertainty in the topographic density distribution data (and thereby in orthometric heights), we conclude that neither GNSS-leveling nor astrogeodetic techniques can reliably verify differences between gravimetric geoid models at several centimeter levels in rough mountainous regions. This is because much the same topographic data are used both in the gravimetric geoid models and in their verifications by geometric and/or astrogeodetic geoid models. On the contrary, this is not a problem in verifying gravimetric quasigeoid models, as they are independent of the topographic density distribution, and so is the related normal height used in GNSS-leveling.

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  • 267.
    Sjöberg, Lars
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), SE-100 44, Stockholm (SWE).
    On the topographic bias by analytical continuation in geoid determination2023In: Studia Geophysica et Geodaetica, ISSN 0039-3169, E-ISSN 1573-1626, Vol. 67, p. 27-38Article in journal (Refereed)
    Abstract [en]

    We consider the topographic bias in gravimetric geoid determination when analytically downward continuing the disturbing potential from the Earth’s surface to sea level. The total bias is subdivided into those of the Bouguer shell or plate and the terrain. In this process, the potential of the Bouguer shell always has a downward continuation bias in the process, which increases with the square of the topographic height and typically exceeds 1−2 cm for elevations higher than 1 km. The main conclusion is that the terrain does not provide a potential bias except possibly for masses located inside a dome of height of about 0.4 times the height of the computation point, and base radius equal to the height of the computation point. This result implies that the potential of all terrain masses of arbitrary density located exterior to the Bouguer shell as well as those outside the dome are unbiasedly downward continued to sea level.

  • 268.
    Sjöberg, Lars
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), SE-100 44 Stockholm (SWE).
    Abrehdary, Majid
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Combination of three global Moho density contrast models by a weighted least-squares procedure2022In: Journal of Applied Geodesy, ISSN 1862-9016, E-ISSN 1862-9024, Vol. 16, no 4, p. -339Article in journal (Refereed)
    Abstract [en]

    Due to different structures of the Earth’s crust and mantle, there is a significant density contrast at their boundary, the Moho Density Contrast (or shortly MDC). Frequently one assumes that the MDC is about 600 kg/m3, but seismic and gravimetric data show a considerable variation from region to region, and today there are few such studies, and global models are utterly rare. This research determines a new global model, called MDC21, which is a weighted least-squares combination of three available MDC models, pixel by pixel at a resolution of 1° × 1°. For proper weighting among the models, the study starts by estimating lacking standard errors and (frequently high) correlations among them. The numerical investigation shows that MDC21 varies from 21 to 504 kg/m3 in ocean areas and ranges from 132 to 629 kg/m3 in continental regions. The global average is 335 kg/m3. The standard errors estimated in ocean regions are mostly less than 40 kg/m3, while for continental regions it grows to 80 kg/m3. Most standard errors are small, but they reach to notable values in some specific regions. The estimated MDCs (as well as Moho depths) at mid-ocean ridges are small but show significant variations and qualities. © 2022 Walter de Gruyter GmbH, Berlin/Boston 2022.

  • 269.
    Sjöberg, Lars E.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Unbiased least-squares modification of Stokes' formula2020In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 94, no 9, article id 92Article in journal (Refereed)
    Abstract [en]

    As the KTH method for geoid determination by combining Stokes integration of gravity data in a spherical cap around the computation point and a series of spherical harmonics suffers from a bias due to truncation of the data sets, this method is based on minimizing the global mean square error (MSE) of the estimator. However, if the harmonic series is increased to a sufficiently high degree, the truncation error can be considered as negligible, and the optimization based on the local variance of the geoid estimator makes fair sense. Such unbiased types of estimators, derived in this article, have the advantage to the MSE solutions not to rely on the imperfectly known gravity signal degree variances, but only the local error covariance matrices of the observables come to play. Obviously, the geoid solution defined by the local least variance is generally superior to the solution based on the global MSE. It is also shown, at least theoretically, that the unbiased geoid solutions based on the KTH method and remove–compute–restore technique with modification of Stokes formula are the same. © 2020, The Author(s).

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  • 270.
    Sjöberg, Lars E.
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Abrehdary, Majid
    On Moho Determination by the Vening Meinesz-Moritz Technique2021In: Geodetic Sciences: Theory, Applications and Recent Developments / [ed] Erol, Bihter & Erol, Serdar, INTECH, 2021, p. 1-19Chapter in book (Refereed)
    Abstract [en]

    This chapter describes a theory and application of satellite gravity and altimetry data for determining Moho constituents (i.e. Moho depth and density contrast) with support from a seismic Moho model in a least-squares adjustment. It presents and applies the Vening Meinesz-Moritz gravimetric-isostatic model in recovering the global Moho features. Internal and external uncertainty estimates are also determined. Special emphasis is devoted to presenting methods for eliminating the so-called non-isostatic effects, i.e. the gravimetric signals from the Earth both below the crust and from partly unknown density variations in the crust and effects due to delayed Glacial Isostatic Adjustment as well as for capturing Moho features not related with isostatic balance. The global means of the computed Moho depths and density contrasts are 23.8±0.05 km and 340.5 ± 0.37 kg/m3, respectively. The two Moho features vary between 7.6 and 70.3 km as well as between 21.0 and 650.0 kg/m3. Validation checks were performed for our modeled crustal depths using a recently published seismic model, yielding an RMS difference of 4 km.

  • 271.
    Sjögren, Jesper
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Strömgård, Frida
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Naturen som arena: En studie i markåtkomstregler för orienteringssporten2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The right of public access is not defined in Swedish law but is based on custom and ancient traditions dating back to the Middle Ages. However, the right of access is mentioned in the legal text, in RF 2 chapter 15 § 4 pcs. as well as in MB 7 chapter 1 §. There are laws that define the utmost limits of the right of public access, such as the rules of brottsbalken such as åverkan, hemfridsbrott, tagande av olovlig väg and egenmäktigt förfarande. However, the right of public access does not define that everything that is not illegal is permitted, and the right of public access requires that respect is shown. Chapter 2 of miljöbalken, Allmänna hänsynsregler m.m. set limits for what all those engaged in activities in nature must follow. In terms of organized outdoor activities, which orienteering is classed as, the right of public access is even more complex. All participants in an event can be within the limits of the right of public access, but it does not mean that the entire event can be held solely based on the right of public access if the damage or disturbance done by all participants is too high. The study intends to investigate what is required for an orienteering event to be conducted based on the right of public access, how organizers today secure access to land for their events and how the level of knowledge regarding the right of public access and current law is today. A survey was sent to 87 associations in southwestern Sweden to investigate how associations secured access to land in connection with their activities and arrangements, which laws, guidelines and policies used by associations in connection with their activities as well as on education in the right of public access are in the association. The survey showed that the level of knowledge in some respects is low among the associations. The associations are good at conducting consultations prior to arrangements, but far from all associations contacted landowners, usufructuaries and owners of hunting rights prior to the making of orienteering maps. Also, only 8% of the associations teach members in right of public access. Contact was taken with authorities and federations to hear how they look at organized outdoor activities. Those who were contacted were the Swedish Orienteering Association, the Swedish Environmental Protection Agency, the County Administrative Board and the Federation of Swedish Farmers. The results obtained from this showed that there are several interpretations on how the right of public access is applied. The Swedish Orienteering Association claims that the right of public access is applicable to all events and that no formal permission is required from the landowner, but consultation with the landowner, any usufructuaries and gamekeeper should always be held. The Federation of Swedish Farmers also says that consultation with the landowner, any usufructuaries and owners of hunting rights always is necessary and that they can deny access if the event has any risk of damaging or disturbing either the nature or the landowner’s interests. The Swedish Environmental Protection Agency in their assessment said that it is not possible to generalize when the right of public access is applicable, without individual assessments at every individual situation. The conclusion that can be drawn from this is that the right to public access is quite complex and to lay down concrete limits for when the right of public access applies and not applicable in connection with orienteering events is difficult. Different land types are affected to a different extent when people pass, and what may be allowed impact in one area may not be allowed on another. Landowners shall not receive or incur material injury or inconvenience for the event to be covered by the right of public access, and what is material injury is also difficult to define.

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  • 272.
    Solberg, Nelli
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Söder, Anton
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Parallell komprimering2018Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This paper compares the use of multiple processes using the compression application pigz which is based on the same algorithms as gzip, as well as discussing utilization optimization and reviewing the performance improvements that can be achieved. Contemporary modern processors use a Multi-Core technology based on an architecture where a physical processor contains multiple logical processors that enable the operating system to perform multiple tasks while utilizing the processors full capacity which enables multiple logical processors to share resources and execution time where available capacity is distributed between cores with the use of threads.

    The paper aims to compare compression speed between pigz and gzip.

  • 273.
    Sporre, Oscar
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Widengård, Simon
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Jämförelse av monitoreringsprotokoll: NetFlow och IP SLA2018Independent thesis Basic level (degree of Bachelor), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    As a technician, it is important to have control and monitor the network. It exists different programs and protocols. This thesis tests two different network monitoring techniques. NetFlow collects data from existing IP flows at an observation point and then is further reviewed through an application installed on a computer. The observation point in this thesis is a router. Cisco IP SLA is the second technology tested. IP SLA generates probes that simulate different types of traffic to review availability, performance and services. To restrict the area of use three tests are performed against different protocols and services. Measurement one is IP telephony conversation between two networks, this to pass the observation point, and to be able to generate a probe with IP SLA over a link between the two routers. IP SLA provides results about link quality for a VoIP call on the link that the measurement package passes. The second measurement is web traffic to a server, even this between the two networks. The web server is implemented in one network and the generated traffic comes from the opposite. In the NetFlow analyzer application you can see the flows of HTTP traffic that are created and pass through the observation points. The last measurement is a port scan against a device in the opposite network to simulate an intrusion attempt. The scan is done with an application called Nmap. The application is looking for open ports towards the destination. When all requests pass the NetFlow observation points, they are captured and presented in the NetFlow application. The results presented in the results section show that they provide different data in different areas of network monitoring. To have the best overall monitoring method, both should be used together as they weigh up different areas and complement each other.

  • 274.
    Spångmyr, Marie
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Nyman, Michaela
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Huvudmannaskap för allmän plats: Fördelning av huvudmannaskap och kommunernas redovisning av särskilda skäl2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When the new Planning and Building Act (hereinafter PBL) was introduced in May 2011, it became possible for the municipalities to combine municipal and private mandatorship, so-called shared mandatorship, within the same detailed development plan. However, the municipalities must, as a basic rule, be responsible for public spaces within the detaileddevelopment plan. To be able to renounce responsibility, they must present special reasons. In January 2015, further provisions were introduced in the PBL, which meant that the cadastral authority will now provide advice in both the consultation and review phase of detailed development plans, including questions concerning mandatorship in detailed development plans.The main purpose of this study is, in the light of the above-mentioned legal provisions, to study how the municipalities manage mandatorship within the detailed development plan and what special reasons they account for a private or shared mandatorship. In addition to the main purpose, the study also intends to study whether there have been any changes after previous studies. A quantitative method was used to map the distribution of mandatorship and a legal dogmatic method to gain an understanding of current law concerning special reasons. In the examination of the municipalities accounted special reasons a qualitative content analysis was used. A total of 1880 detailed development plans from Västra Götaland, Skåne and Stockholm counties were studied, of which 1347 detailed development plans contained public space. It was found that 89 % were established with municipal mandatorship, 9 % with private mandatorship and 2 % with shared mandatorship. When there was a shared mandatorship, the municipality is usually responsible for walk and bicycle roads, nature, streets and main streets while the individuals are responsible for smaller nature- and park areas as well as local streets. Private or shared mandatorship appeared in 142 detailed development plans, of which 280 special reasons were accounted. For the municipalities accounted reasons only 50% are judged to be legal, 41 % illegal, while 9 % of the detailed development plans did not account any special reasons. In comparison with previous studies, the results indicate that municipal mandatorship is applied to a greater extent today and that accounting for special reasons and the proportion of legal special reasons has increased. Surprisingly, however, non-legal reasons are reported to the same extent as before.

  • 275.
    Sundararajan, Narasimman
    et al.
    Sultan Qaboos University, Department of Earth Sciences, Muscat, Oman.
    Eshagh, MehdiUniversity West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.Saibi, HakimUnited Arab Emirates University,Abu Dhabi, United Arab Emirates.Meghraoui, MustaphaUniversité de Strasbourg, Strasbourg, France.Al-Garni, MansourKing Abdulaziz University, Jeddah, Saudi Arabia.Giroux, BernardCentre Eau Terre Environnement,Institut National de la Recherche Scientifique, Québec, Canada.
    On Significant Applications of Geophysical Methods: Proceedings of the 1st Springer Conference of the Arabian Journal of Geosciences (CAJG-1), Tunisia 20182019Collection (editor) (Other academic)
    Abstract [en]

    This edited volume is based on the best papers accepted for presentation during the 1st Springer Conference of the Arabian Journal of Geosciences (CAJG-1), Tunisia 2018. This special volume is of interest to all researchers practicing geosphysicists/seismologists, students of PG and UG in the fields of multifaceted Geoscience. Major applications with relevant illustrations presented in the volume are from Middle East. And therefore, this book no doubt would serve as a reference guide to all geoscientists and students in the broad field of Earth Science. This volume covers significant applications of gravity and magnetic methods, electrical and electromagnetic methods, refraction and reflection seismic methods besides a large number of study on earthquakes, tectonics and geological settings etc. The salient features of this volume are the interpretation and modeling of geophysical data of different nature

  • 276.
    Sundström, Jonathan
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Månsson, Adrian
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Samhällsplanering och boendesegregation: I ny och befintlig bebyggelse2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The issue of segregation has become a major issue both within the national level and municipal level where the problem is to be solved. Solutions to the housing crisis in the 60-70s now result in housing segregation. The report highlights the socioeconomic part of segregation, which describes both living segregation and housing segregation. The report describes why housing segregation exists and how there are common factors in these areas.

    The aim is to investigate how a physical planner can contribute with their tools to successfulreduce the housing segregation in the city.

    Collection of information has been compiled at the same time as three comprehensive plansfor Gothenburg, Trollhättan and Mölndal and three interviews have been analyzed and presented in the result, to see how the municipalities are posing the question and what their solution is.

    The report presents the various tools that urban planners must use, examples of the various tools are comprehensive plans, contracts with developers and laws.

    The report concludes with its own reflections in a discussion and conclusion. These show that the subject is complicated and that there is no simple solution. Examples of solutions are presented for both new and existing buildings, such as mixed form of lease and opportunity for housing career. The transformation between segregation and integration in a city takes a long time, and it is difficult to determine the causes and measure the impact of different integration measures.

  • 277.
    Söder, Anton
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Solberg, Nelli
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    gQUIC: HTTP över UDP2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    TCP is a well-established protocol that is used to a greater extent where data transmission reliability is more desired than fast data flows. Like TCP, gQUIC is a connection-oriented and reliable protocol that offers a number of built-in functions and optimizations to achieve lower times when establishing connections and transmitting data.

    To verify this, a series of tests are made that show that gQUIC achieves lower times when establishing encrypted connection, which can be of great importance when using devices that move between networks as the time for establishing the connection can be reduced. Furthermore, the tests show that downloading web content with TCP is faster at low or no packet loss while gQUIC is faster at higher packet loss.

  • 278.
    Söder, Lukas
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Viitala, Oskar
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    SD-WAN som alternativ till traditionellt WAN2021Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    Denna undersökning ämnar utreda åt en specifik verklig organisation angående vilken Wide-Area-Network (WAN) lösning som lämpar sig bäst efter deras behov. Idag använder organisationen Multi Protocol Label Switching (MPLS) -förbindelser mellan sina kontor, och har lagt fram som önskemål att eventuellt ersätta det med Software-Defined WAN (SD-WAN) över internet om den lösningen kan upprätthålla samma tillgänglighets samt kvalitetskrav som MPLS.

    Syftet med arbetet är att utreda åt organisationen om SD-WAN över internet kan vara ett alternativ till den WAN-teknik i form av MPLS som de använder idag.Anledningen till att se på en eventuell ersättare till MPLS var enligt organisationen att WAN-länkar mellan kontoren kan bli överbelastade ibland, vilket i sin tur medför att applikationer upplevs gå långsamt. Därför vill organisationen undersöka om det överhuvudtaget går att ersätta SD-WAN över internet som en alternativ lösning i stället för att utökning kapaciteten på befintliga MPLS-förbindelser.

    Det har utretts vilket användarmönster som organisationen använder sig av när det gäller moln och IT-tjänster.

    Utvärdering och mätning av kundens befintliga nät samt önskemål har gjorts i samband med faktainsamling för att kunna få fram ett rimligt resultat. Resultatet pekade på att befintligt nät påvisar god kvalitet och ett byte från MPLS till SD-WAN över internet inte rekommenderas på grund av organisationens krav på kvalité och tillgänglighet samt deras begränsade användning av molntjänster ute på internet.

    Diskussionen pekade på att SD-WAN kan vara ett framtida alternativ hos organisationen, inte som en ersättare av MPLS-nätet men som ett komplement då viss typ av icke-kritisk trafik kan styras över internet i stället för att belasta MPLS-länkarna, det kallas för hybrid-WAN.

  • 279.
    Tamrell, Martina
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Sjögren, Jennifer
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Ändring och rättelse i detaljplan2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study is to investigate and account for differences and similarities between correction and change of detailed development plan. The work also aims to identify the consequences of errors that have arisen, and how municipalities handle these. Furthermore, the survey aims to investigate who are the stakeholders and what communication takes place between the municipality and the stakeholders. The aim of the study is to provide a knowledge contribution of what happens when errors occur in a detailed development plan and what is required to be able to apply correction. The study has been carried out largely through a qualitative method with a literature study and interviews that are complemented with a quantitative contribution in the form of collected corrections. The selection for interviews was based on officials who work in a municipality with detailed development plans daily. The spread of municipalities was varied around the Västra Götaland region from country municipality to bigcity. The corrections are presented in a chart and were used to show the type of corrections municipalities make. The corrections were 20 pcs in number and were selected through its availability via search engines. The criteria were that the corrections should be valid and not appealed and could not be older than in 2011. No corrections were filtered away. The result was divided into chapters on current law and empirical evidence. Current law presents answers to the questions from a legal point of view, which legislation is relevant for the purpose of the study. The PBL describes a change and the process required. Simple procedure, standard procedure and extended procedure are accounted for in the context of the application of preparatory work. An amendment to a detailed plan shall undergo some of the procedure even if only part of the plan is amended. FL explains the criteria that must be met for a correction to be implemented. The error must, among other things, be of an obvious nature and caused by a typing error, arithmetic error or technical error. Legal cases from MMD,RR and MÖD report how the court interpreted § 36 FL, where MÖD 2018 gave a judgment that can guide municipalities in the interpretation of legal text. MÖD ruled against the municipality and stated as a reason that the correction in question entailed a change in substance in the detailed plan, also to the detriment of an individual, and did not meet the criteria that the legislators considered a correction. In analysis and discussion, the corrections from municipalities are analyzed together with material from interviews, applicable law and court cases. The analysis shows that the municipalities have interpreted FL in different ways and that they have justified decisions on correction of different designs. The majority of the corrections studied do not turn out to meet the minimum requirements set by FL for correction, nor did it turn out that there was support in the form of legal cases for the majority of the corrections. The results from the officials' interviews, on the other hand, mostly turn out to be in line with what the legislator intended. The officials agreed that a plan may not be corrected if it involves a change in the plan, then the plan must undergo a change through PBL. Through the study, it has proved difficult to draw a straight line between correction according to FL and change through PBL. Municipalities interpret an obvious error and change in substance in different ways, which has resulted in the legal cases presented in the study. Conclusions that have been drawn are that FL is far too general and PBL far too narrow to easily implement minor corrections. FL only allows trivial errors while PBL makes excessive demands when adjusting small errors.

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  • 280.
    Tano, Ingrid
    University West, Department of Engineering Science, Division of Natural Sciences and Electrical and Surveying Engineering. University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Contributions to multivariate process capability indices2012Licentiate thesis, comprehensive summary (Other academic)
  • 281.
    Tano, Ingrid
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Lycke, Liselott
    A Guide to Develop Quality Assurance System within HEIs2019Conference paper (Other academic)
    Abstract [en]

    Purpose: Describe and develop a guide to help HEIs(Higher Education Institutions) to develop a Quality Assurance System, which engages both managers, teachers and other coworkers involved in the education process.

    Design/methodology/approach: Case study, action research

    Findings: We highlight the problem to get involvement from teachers and other co-workers working with a Quality Assurance System. Therefore we suggest a guide, which will increase the understanding, engagement and involvement for quality assurance in HEIs.

    Originality/Value: The guide creates opportunities for successful quality assurance and quality control in HEIs, with its complexity. The guide follows the education process and has a process-oriented approach.

    Keywords: Higher Education, Quality Assurance System, Quality Management, Learning Meeting, Work Integrated Learning

    In September 2016 the Swedish Higher Education Authority presented a new system for quality assurance in higher education (HE) that includes both monitoring and enhancement of quality work. The new national system demands HEIs to develop their own Quality Assurance Systems and adopt the new national system to its own context. This paper describes an internal guide created to support the departments work to expand their Quality Assurance System from just monitoring to include enhancement of quality work in an applied context. The aim of the Guide is to support departments to identify which activities that need to be systematized and what needs to be documented and communicated in order to achieve both monitoring and enhancement of quality work. The Guide follows a common education process in order to assure quality in the most vital activities in the process. This paper will describe the Guide and the connection to the education process and show that the Guide is generalizable to education processes in other HEIs. The paper also suggests that when working with the Guide during so-called Learning Meetings, the organization will adapt Work Integrated Learning when developing new knowledge and hereby building a chain of trust in the organization.

  • 282.
    Thorsell, Elias
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Johansson, Filip
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Ägarlägenheter i kontorsbyggnader2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2012, Kunskapsporten built an office building in Hässleholm, Sweden. This building introduced a new form of housing for Sweden, owner-occupied apartments as an alternative use for the top floor of office buildings. This building sparked the idea for this bachelor thesis, that is if owner-occupied apartments is an advantageous use for the top floors of office buildings. Owner-occupied apartments is not as prevalent as the condominiums and rental apartments with only 1900 existing owner-occupied apartments.

    There are many office buildings being built and planned for within the cities. There is also a housing shortage that leads many to look outside of the cities for housing. Using office buildings with owner-occupied apartments creates more homes and gives an economic advantage to the construction company, who can directly sell the apartments to make up for construction costs.

    The purpose of this bachelor thesis is to see if it is sustainable to introduce owner-occupied apartments in tall office buildings and to explore the possibility of rebuilding existing office floors into owner-occupied apartments. The problem that exists in owner-occupied apartments in office buildings is how the common areas are to be handled, if it is economically advantageous with owner-occupied apartments instead of offices and how to make a conversion from office to apartment possible.

  • 283.
    Warås, Anna
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Wassenius, Elin
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Kommuners möjligheter att påverka samhällsbyggnadsprocessen rörande framtidens mobilitet2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study is a thesis project commissioned by Trollhättan City to investigate the influenceof different city council within the community building process regarding the mobility of the future. The basic survey is aimed at comparing Trollhättan City, Borås City and Umeå City center’s using public documents and interviews. Due to the restrictions of the pandemic, all interviews have been conducted remotely.The aim is to account for the opportunities for city council to influence the civil engineering process regarding the mobility of the future. Which is reported through methods, plans, programs, collaborations and more. The main method of influence is to enable sustainable travel while responding to the behavioral changes of residents. To influence transports through traffic infrastructure by working at a basic level to plan the city right from an early stage, with good cooperation from several actors. At the same time, the possibility of introducing shared mobility as an impact method can be introduced for a more sustainable travel option. It also requires an understanding that smart mobility does not always mean sustainable mobility, but at the same time explain that new alternative future mobility solutions can promote road safety and reduce environmental impact. To perform methods that create the interest in being able to replace the convenience of the car. The holistic approach is based on early-stage cooperation based on influencing residents' behavior and practices at a good level that does not create unnecessary conflicts. The conclusion is that cooperation is required from an early stage with this holistic approach to be able to connect all the different ideas and solutions.

  • 284.
    Widekärr, Camilla
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Porath Holmqvist, Linda
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Digitalisering av befintliga detaljplaner: Fastighetsgränser2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To meet today's need for more housing large resources are invested in the construction sector through digitalization. With this report we want to clarify the problem of Property boundaries in a future digital community building process. This is a question worth creating awareness of to show the dilemmas municipalities face, in the pursuit of a digital future. The purpose of this report is to investigate how boundaries in the digitala registerkartan are handled as municipalities digitize existing detailed development plans. This is to capture the approaches used and with this draw conclusions about appropriate methods that can benefit the community building process. The survey was carried out by interviewing officials at municipalities that are engaged in this work. They described the approach to their work and reflected on expected positive effects as well as the problems they encountered. A digitized community building process also has consequences for social, economic, and ecological sustainability.

    A parallel that can be drawn to the digitala registerkartan is that it was created in a forced work in the 1990s with situational uncertainty on boundaries. Consequences of this have been revealed over time. The result reflects that accuracy of the boundaries plays a major role depending on what the material is to be used for, as the quality is controlled by its use at a later stage. To avoid similar situations with future developments, such as building automated building permit management, the quality of boundaries should be reliable. The study shows that national guidelines are lacking, after which municipalities have had to test themselves based on the economic and organizational terms that are available in municipality. As far as the social, economic, and ecological sustainability is concerned, the first two draw benefit from faster decisions, but it is unclear whether increased housing can be compatible with ecological sustainability. 

  • 285.
    Widengård, Simon
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Cogelja, Tony
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Live migrering av en virtuell brandvägg under last2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Virtualisation is becoming more and more popular to use. VMware is a service that offers virtualisation of hardware. This means that it's possible to virtualize multiple machines on one server, this to save on cost, space and ease of management. Tests are made by sending Iperf data through a client to an Iperf server. Between these two virtual machines lies a software firewall that's using pfSense. Meanwhile the Iperf client is sending data to the server, a vMotion migration is executed to another ESXi. This investigation is about seeing how vMotion can handle a software firewall, that handles traffic at the same time it's about to migrate the virtual machine to another ESXI.

    The results showed that when utilizing the 1000 Mbit/s link to the max, the transfer speed of the Iperf client is lowered to make room for vMotion traffic. You can see depending on the bandwidth that it is affecting the migration times. The migration is going through but the time it takes is longer.

  • 286.
    Xu, Fenglei
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Performance evaluation and comparison of Dual-NIC computer Optiplex 780 with Cisco 2901 router2018Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Evaluation of the dual-NIC computer Dell Optiplex 780 (henceforth referred to as PCR1) compared with Cisco 2901 router regarding performance.

    Both devices are tested to show maximum throughput with increasing numbers of parallel links. A Cisco Catalyst 2960G switch is used to provide more access ports. The software Iperf is used throughout the tests as both traffic generator and throughput measuring tool, meanwhile the software Dstat on PCR1 is used for CPU usage measuring. PCR1 and Cisco 2901 are tested separately. A few basic tests are performed in phase 1 to discover the maximum throughput between the devices' interfaces. In phase 2, additional client computers are added on one side of the router device, one pair at a time. All these clients receive max-load traffic simultaneously from a single server computer, which reside on the other side of the router. Phase 2 tests are meant to investigate how well the router devices handle max-load traffic in a situation where there are multiple clients, whether they prioritize any traffic or function abnormally.

    After both phases are done, an analysis of the collected data is presented, both devices's performance and differences between them will be analysed.

  • 287.
    Yousofi, My
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Lantmäterimyndighetens yttranden under samråd och granskningstiden samt kommunernas ställningstagande2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Detail development plans are a way for the municipalities to regulate the use of land and water territories. The map that follows with the detail development plan is a legal document used by the municipalities to shape the area of the plan by using plan regulations. With the map follows a plan description which describes the purpose of plan, presents the implementation of the plan and the consequences it has on interested parties, the environment and other parties that could be affected by the detail development plan.

    In the case of deficient plan regulations och plan description the consequences for the afflicted parties can lead to costly and drawn out processes. Earlier studies showed that 17 % of all approved detail development plans contained deficient plan regulations.

    According to earlier regulations, the municipalities did not have to consult with the cadastrial authorities for every planning proposal. During this time, the role of the cadastral authority was to make sure the plan regulations refering to property law were correct in their configuration not to cause negative consequenses to the implementation of the detail development plan. The role of the cadastral authories changed in conjunction with a constitutional amendment to the law which took effect 1 januari 2015. The government wanted to make the planning implementation more effective and one way to achieve this was to give the cadastral authority a more distinct and extended role during the planning process.

    The purpose of this study is to examine how the municipalities respond to comments made by the cadastral authority during the review time. The result shows that after the first review time 12 % of the detail development plans that the cadastral authority made remarks on had not been corrected by the municipalities. After the second review time, the procentage had decreased to 7 % of all detail development plans. When comparing the actions taken by municipalities with communal cadastral authority and municipalities with state cadastral authority the analysis showed that there where no significant differences between them.

    The studie indicates that the municipalities listen to the opinions and advice given by the cadastral authority, thereby deficient plan regulations and plan descriptions are amended accordingly. This will hopefully lead to a more effective implementation of the detail development plans.

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  • 288.
    Zampal, Luigi
    et al.
    University of Trieste, Department of Mathematics and Geoscience, Trieste, Italy.
    Tenzer, Robert
    Hong Kong Polytechnic University, Department of Land Surveying and Geo-Informatics, Hong Kong.
    Eshagh, Mehdi
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Pitonak, Martin
    University of West Bohemia, New Technologies for the Information Society (NTIS), Faculty of Applied Sciences, Czech Republic.
    Evidence of mantle upwelling/downwelling and localized subduction on Venus from the body-force vector analysis2018In: Planetary and Space Science, ISSN 0032-0633, E-ISSN 1873-5088, Vol. 157, p. 48-62Article in journal (Refereed)
    Abstract [en]

    Considering that Venus has a size very similar to Earth, thermal evolution of both planets should be comparable. Nonetheless, there is no clear evidence of plate tectonics or plate motions on Venus. Instead, various surface deformations attributed to volcanism, resurfacing, localized subduction and other geologic processes were recognized on the planet. In this study we attempt to classify the origin of lithospheric forces on Venus based on using topographic and gravity information. For this purpose, we also estimate the Venusian crustal thickness. In agreement with findings from previous studies, the signature of past or recent global tectonism in the body-force vector pattern on Venus is absent, while exhibiting only regional anomalies. The maximum intensity inferred in the Atla and Beta Regios is likely attributed to mantle upwelling. This is also confirmed by the gravity-topography spectral correlation and admittance analysis that shows the isostatic relaxation of these volcanic regions. The regional body-force pattern in the Bell Regio suggests that a much less pronounced force intensity there is possibly related to crustal load of lava flows. Elsewhere, the body-force intensity is relatively weak, with slightly more pronounced intensity around the Ishtar Terra and the Arthemis Chasmata. The body-force pattern in the Arthemis Chasmata supports the hypothesis that coronae structures are the result of mantle upwelling and the subsequent (localized) plume-induced subduction with only limited horizontal crustal motions. The prevailing divergent pattern of body-force vectors in the Ishtar Terra region suggests the presence of tensional forces due to the downwelling mantle flow that is responsible for a crustal thickening along the Freyja and Maxwell Montes. Except for the Atla and Beta Regios where the isostasy is relaxed by the (active) mantle plumes, the crustal thickness is spatially highly correlated with the topography, with a thin crust under the plains and a thick crust under the plateaus. The maximum Moho depth under the Maxwell Montes in the Ishtar Terra exceeds 90 km.

  • 289.
    Zetterström, Jesper
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Wiklund, Mikael
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Hur överbelastningsattacker påverkar funktioner inom en router2020Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    In this report the reader will be informed on what denial-of-service is and how it affects the three different planes of operation in a router. These three are as follows, management plane, control plane and data plane.

  • 290.
    Överengen, Anders
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Lundgren, Axel
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Trafikpåverkan av konvergens i OSPFv2 och EIGRP2021Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The thesis has explored what type of traffic flow between FTP, video and voice that was most affected by link failure. Measurements of the traffic flows have been carried out using the routing protocols OSPF and EIGRP. The results have been compared to measure what routing protocol that affected the traffic flows the most. The results focus on break timesin the traffic flows, lost packets due to link failures, and how long it took the applications to reestablish their traffic flows after full convergence in the routing protocols. The tests have been performed using three Cisco routers, two layer-3 switches and two Windows 10 computers. The topology consists of five network devices to create three redundant paths from the client LAN to the server LAN. The results have shown that EIGRP was the better protocol with the lowest impact on the applications.

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