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  • 46401.
    Wu, Yongchao
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Zhang, Jiawei
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Name Resolution Information Distribution in NetInf2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Information-Centric Networking (ICN) is a different architecture from today's Internet, which is host-centric. In ICN, content is requested by the names of content objects instead of network or host addresses. This feature allows for a number of advantages, such as in-network caching and request aggregation. Network of Information (NetInf) is an ICN architecture. It is an overlay on TCP/IP, which translates content object names to locators or IP addresses. NetInf is designed to facilitate initial deployment and migration from today's networks to ICN.

    In an ICN network, content can be cached at numerous locations giving a client the possibility to retrieve content from a number of available sources. In order to retrieve a content object, a client does a lookup in a Name Resolution Service (NRS) to resolve the content name into a set of locators where the content is stored. By distributing the location information of content objects from the NRS to NetInf nodes in the network the lookup time and overhead caused by the lookup messages can be reduced. Hence resulting in better end-user experience and more efficient network utilization. In this thesis, two methods to distribute location information of content objects in a NetInf network have been proposed and evaluated against a reference model where the location information is hosted centrally in an NRS. The effectiveness of the proposed methods has been evaluated by running simulations on a NetInf simulator (built on OMNeT++) that was built during the course of this project.

    Evaluation results show that the proposed methods reduce the lookup/name resolution latency of content objects. The results also compare the overhead caused by each one of the proposed methods in terms of network utilization. We also show the results that the network topology has an impact on the effectiveness of the proposed methods and therefore is a factor that needs due consideration in deciding which method is suitable when.

  • 46402.
    Wu, Yuan-Zhong
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Ottosson, Alexander
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Visualiseringsverktyg för röstkommunikation2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Saab har utvecklat en produkt, Remote Tower, som tillåter flygledningen att fjärrstyra en flygplats, det vill säga att övervaka och kontrollera en flygplats på distans. Ett viktigt verktyg för flygledarna är VCS, Voice Communication System, som är Saabs egna röstkommunikationssystem, där både radio- och telefonkommunikation ingår. VCS används för att kommunicera med piloter och markpersonal på flygplatsen. Målet är att i framtiden kunna fjärrstyra fler flygplatser samtidigt, och då finns ett behov att visualisera de inkommande samtalen från de olika flygplatserna i realtid. Detta för att undvika ett scenario där flygledaren missar ett samtal. Ett system har utvecklats för just detta ändamål vars huvuduppgift är att visualisera de samtal som VCS producerar. Systemet kan hantera tre flygplatser samtidigt, och varje samtal kan spelas upp genom att klicka på de inkommande samtalen.

  • 46403.
    Wu, Yucheng
    Social Wireless Network Secure Identification.
    A secure mobile social network2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Mobile social networks are a new trend to improve the quality of our life, so they should not bring any extra burden to users. The users should not anymore be worried how to set up a secure complex password and memorize it to prove their identities. The Generic Bootstrapping Architecture is used in this thesis as a novel way of authentication. The GBA protocol allows to generate and share cryptographic keys between a mobile phone and third party service providers using the operator as intermediary. These keys are generated transparently without any user interaction. In a traditional mobile social network, an Internet connection is compulsory but we believe this should not be a barrier in the future. An ad-hoc network may be used to communicate in a private group of friends. Thus, users need to be capable of verifying membership assertions and generating offline invitations for new friends without a connection to the social network server. Our implementation uses SAML assertions to certify group memberships and offline invitations. Beside these security solutions, a real mobile social network has been implemented, using the REST framework for communication and databases for storing information both on the client and the social network server.

  • 46404. Wu, Z.
    et al.
    Cao, J.
    Mao, Bo
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Geodesi och geoinformatik.
    Wang, Y.
    Semi-SAD: Applying semi-supervised learning to shilling attack detection2011Ingår i: RecSys - Proc. ACM Conf. Recomm. Syst., 2011, s. 289-292Konferensbidrag (Refereegranskat)
    Abstract [en]

    Collaborative filtering (CF) based recommender systems are vulnerable to shilling attacks. In some leading e-commerce sites, there exists a large number of unlabeled users, and it is expensive to obtain their identities. Existing research efforts on shilling attack detection fail to exploit these unlabeled users. In this article, Semi-SAD, a new semi-supervised learning based shilling attack detection algorithm is proposed. Semi-SAD is trained with the labeled and unlabeled user profiles using the combination of naïve Bayes classifier and EM-λ, augmented Expectation Maximization (EM). Experiments on MovieLens datasets show that our proposed Semi-SAD is efficient and effective.

  • 46405.
    Wu, Zhenzhi
    et al.
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska fakulteten. Beijing Institute Technology, Peoples R China.
    Gong, Chen
    Beijing Institute Technology, Peoples R China.
    Liu, Dake
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska fakulteten. Beijing Institute Technology, Peoples R China.
    Computational Complexity Analysis of FEC Decoding on SDR Platforms2017Ingår i: Journal of Signal Processing Systems, ISSN 1939-8018, E-ISSN 1939-8115, Vol. 89, nr 2, s. 209-224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The computational complexity evaluation is necessary for software defined Forward Error Correction (FEC) decoders. However, currently there are a limited number of literatures concerning on the FEC complexity evaluation using analytical methods. In this paper, three high efficient coding schemes including Turbo, QC-LDPC and Convolutional code (CC) are investigated. The hardware-friendly decoding pseudo-codes are provided with explicit parallel execution and memory access procedure. For each step of the pseudo-codes, the parallelism and the operations in each processing element are given. Based on it the total amount of operations is derived. The comparison of the decoding complexity among these FEC algorithms is presented, and the percentage of each computation step is illustrated. The requirements for attaining the evaluated results and reference hardware platforms are provided. The benchmarks of state-of-the-art SDR platforms are compared with the proposed evaluations. The analytical FEC complexity results are beneficial for the design and optimization of high throughput software defined FEC decoding platforms.

  • 46406. Wubs, Fred W.
    et al.
    Thies, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen.
    A Robust Two-Level Incomplete Factorization for (Navier-)Stokes Saddle Point Matrices2011Ingår i: SIAM Journal on Matrix Analysis and Applications, ISSN 0895-4798, E-ISSN 1095-7162, Vol. 32, nr 4, s. 1475-1499Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a new hybrid direct/iterative approach to the solution of a special class of saddle point matrices arising from the discretization of the steady incompressible Navier-Stokes equations on an Arakawa C-grid. The two-level method introduced here has the following properties: (i) it is very robust, even close to the point where the solution becomes unstable; (ii) a single parameter controls fill and convergence, making the method straightforward to use; (iii) the convergence rate is independent of the number of unknowns; (iv) it can be implemented on distributed memory machines in a natural way; (v) the matrix on the second level has the same structure and numerical properties as the original problem, so the method can be applied recursively; (vi) the iteration takes place in the divergence-free space, so the method qualifies as a "constraint preconditioner"; (vii) the approach can also be applied to Poisson problems. This work is also relevant for problems in which similar saddle point matrices occur, for instance, when simulating electrical networks, where one has to satisfy Kirchhoff's conservation law for currents.

  • 46407. Wuhib, Fetahi
    et al.
    Dam, Mads
    CNS.
    Stadler, Rolf
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A Gossiping Protocol for Detecting Global Threshold Crossings2010Ingår i: IEEE Transactions on Network and Service Management (TNSM), Vol. 7, nr 1Artikel i tidskrift (Refereegranskat)
  • 46408. Wuhib, Fetahi
    et al.
    Dam, Mads
    RISE., Swedish ICT, SICS.
    Stadler, Rolf
    RISE., Swedish ICT, SICS.
    Gossiping for threshold detection2009Konferensbidrag (Refereegranskat)
  • 46409. Wuhib, Fetahi
    et al.
    Stadler, Rolf
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Distributed monitoring and resource management for large cloud environments2011Konferensbidrag (Refereegranskat)
  • 46410. Wuhib, Fetahi
    et al.
    Stadler, Rolf
    RISE, Swedish ICT, SICS.
    Lindgren, H.
    Dynamic Resource Allocation with Management Objectives: Implementation for an OpenStack Cloud2012Konferensbidrag (Refereegranskat)
  • 46411. Wuhib, Fetahi
    et al.
    Stadler, Rolf
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Spreitzer, Mike
    A Gossip Protocol for Dynamic Resource Management in Large Cloud Environments2012Ingår i: IEEE Transactions on Network and Service management (TNSM), Vol. 9Artikel i tidskrift (Refereegranskat)
  • 46412. Wuhib, Fetahi
    et al.
    Stadler, Rolf
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Spreitzer, Mike
    Gossip-based Resource Management for Cloud Environments2010Konferensbidrag (Refereegranskat)
  • 46413.
    Wuhib, Fetahi Zebenigus
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    Distributed Monitoring and Resource Management for Large Cloud Environments2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Over the last decade, the number, size and complexity of large-scale networked systems has been growing fast, and this trend is expected to accelerate. The best known example of a large-scale networked system is probably the Internet, while large datacenters for cloud services are the most recent ones. In such environments, a key challenge is to develop scalable and adaptive technologies for management functions. This thesis addresses the challenge by engineering several protocols  for distributed monitoring and resource management that are suitable for large-scale networked systems. First, we present G-GAP, a gossip-based protocol we developed for continuous monitoring of aggregates that are computed from device variables. We prove the robustness of this protocol to node failures and validate, through simulations, that its estimation accuracy does not change with increasing size of the monitored system under certain conditions. Second, we present TCA-GAP, a tree-based protocol, and TG-GAP, a gossip-based protocol for the purpose of monitoring threshold crossings of aggregates. For both protocols, we prove correctness properties and show, again through simulations, that both protocols are efficient, by showing that their overhead is at least two orders of magnitude smaller than that of a na\"ive approach, for cases where the monitored aggregate is sufficiently far from the threshold. Third, we present a gossip-based protocol for resource management in cloud environments. The protocol allocates CPU and memory resources to sites that are hosted by the cloud. We prove that the resource allocation computed by the protocol converges exponentially fast to an optimal allocation, for cases where sufficient memory is available. Through simulations, we show that the quality of the resource allocation approaches that of an ideal system when the total memory demand decreases significantly below the memory capacity of the entire system. In addition, we validate that the quality of the allocation does not change with increasing the number of hosted sites and machines, for the case where both metrics are scaled proportionally. Finally, we compare two approaches (tree-based and gossip-based) to engineering protocols for distributed management, for the case of real-time monitoring. Results of our simulation studies indicate that, regardless of the system size and failure rates in the monitored system, gossip protocols incur a significantly larger overhead than tree-based protocols for achieving the same monitoring quality (e.g., estimation accuracy or detection delay).

  • 46414. Wulf, O.
    et al.
    Arras, Kai Oliver
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Christensen, Henrik
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Wagner, B.
    2D mapping of cluttered indoor environments by means of 3D perception2004Ingår i: Proceedings - IEEE International Conference on Robotics and Automation, 2004, nr 4, s. 4204-4209Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a combination of a 3D laser sensor and a line-base SLAM algorithm which together produce 2D line maps of highly cluttered indoor environments. The key of the described method is the replacement of commonly used 2D laser range sensors by 3D perception. A straightforward algorithm extracts a virtual 2D scan that also contains partially occluded walls. These virtual scans are used as input for SLAM using line segments as features. The paper presents the used algorithms and experimental results that were made in a former industrial bakery. The focus lies on scenes that are known to be problematic for pure 2D systems. The results demonstrate that mapping indoor environments can be made robust with respect to both, poor odometry and clutter.

  • 46415.
    Wulff, Annegrete
    Statistics Denmark.
    Eyes Wide Shut - Or Using Eye Tracking Technique to Test a Website2007Ingår i: International Journal of Public Information Systems, ISSN 1653-4360, Vol. 3, nr 1, s. 1-12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This presentation provides an introduction to the technique called "Eye Tracking" which Statistics Denmark has recently used to test the usability of its website user interface. Eye tracking is a tool used to analyse "human - computer" interaction. The user's eye movements and fixation time are both registered when this technique is used. However, whether the person actually perceives what the eyes are fixed on is not documented. Statistics Denmark has tested this method on ten users who were asked to carry out particular tasks on the website. It is open to discussion whether the method is strong enough to be used independently. Some of the results were quite persuasive and supported the comments from other users. However, we suggest that eye tracking should not be the only method employed, but it should be used in combination with more traditional usability methods such as, "think aloud" and follow-up interviews.

  • 46416.
    Wursthorn, Amelie
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Determination of Call Graphs in Web Service Structures2012Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This work is part of a project which addresses a detection of the most suitable Webservice for the needs of a particular end user within service oriented architecture (SOA).As of today a research group located at Karlsruhe University of Applied Sciences,Germany, and Linnæus University, Sweden developed a framework which obtainsknowledge about quality of services. Thereby this framework offers the possibility toregister several Web services and guarantees the routing of the communication betweenthem through an Enterprise Service Bus (ESB) implementation developed by this group.The project raises several issues that have to be solved in order to reach the aim ofproviding a framework which selects the most suitable services based on non-functionalcriteria like response time or reliability.Web services call each other to provide their own functionality.The first aim of this work is to redirect released requests (sub-requests) which areinitiated by previous requests (sub-requests), or to manipulate specific data,respectively. A sub-request should then call a specified service which had prior to thisbeen selected by the framework.The next and main part of this work deals with providing data which keepinformation about the relation between requests and those requests released by a Webservice as a reaction of these initial calls. This data is the basis input for later calculatingof call graphs. This issue leads to further questions: The information about Web servicecalls is not reported by the standard log output of the host server. The approach for asolution has to define a way to record the Web service requests and their dependenciesamong each other.For verifying the concept an implementation will demonstrate the successful result.

  • 46417. Wyatt, Jeremy L.
    et al.
    Aydemir, Alper
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Brenner, Michael
    Hanheide, Marc
    Hawes, Nick
    Jensfelt, Patric
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Kristan, Matej
    Kruijff, Geert-Jan M.
    Lison, Pierre
    Pronobis, Andrzej
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Sjöö, Kristoffer
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Vrecko, Alen
    Zender, Hendrik
    Zillich, Michael
    Skocaj, Danijel
    Self-Understanding and Self-Extension: A Systems and Representational Approach2010Ingår i: IEEE T AUTON MENT DE, ISSN 1943-0604, Vol. 2, nr 4, s. 282-303Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There are many different approaches to building a system that can engage in autonomous mental development. In this paper, we present an approach based on what we term self-understanding, by which we mean the explicit representation of and reasoning about what a system does and does not know, and how that knowledge changes under action. We present an architecture and a set of representations used in two robot systems that exhibit a limited degree of autonomous mental development, which we term self-extension. The contributions include: representations of gaps and uncertainty for specific kinds of knowledge, and a goal management and planning system for setting and achieving learning goals.

  • 46418.
    Wyke, Oskar
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    User Centered Design for Persons with Disabilities – How persons with cerebral palsy can be included in the design process.2011Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Användarcentrerad design är ett ramverk byggt på metoder som syftar till att inkludera användaren i designprocessen. När ett system, som ska användas av personer med allvarliga funktionsnedsättningar designas, introduceras ett antal unika svårigheter.

    Detta examensarbete undersöker vilka särskilda faktorer som måste tas i beaktande då en design för ögonstyrd interaktion skapas samt hur användare kan inkluderas trots närvaron av allvarliga funktionsnedsättningar.

    Personer från tre habiliteringscenter i stockholmsområdet inkluderades i studien som implementerades som en iterativ designprocess där metoder, vanliga inom användarcentrerad design, tillämpades.

    Resultatet av studien indikerar att många välkända metoder inom användarcentrerad design kan användas för att inkludera användare med Cerebral Pares. Fokus flyttas något från användaren till personer i dennes omgivning. För att åstadkomma hög användbarhet måste systemet tillhandahålla möjligheten till individuella anpassningar av färger, storlekar och placering av objekten på skärmen. En tvåstegsmetod, som minskar antalet ofrivilliga val, presenteras också.

  • 46419.
    Wynen, Daan
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    Convolutional Kernel Networks for Action Recognition in Videos2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    While convolutional neural networks (CNNs) have taken the lead for many learning tasks, action recognition in videos has yet to see this jump in performance. Many teams are working on the issue but so far there is no definitive answer how to make CNNs work well with video data. Recently, introduced convolutional kernel networks, a special case of CNNs which can be trained layer by layer in an unsupervised manner. This is done by approximating a kernel function in every layer with finite-dimensional descriptors. In this work we show the application of the CKN training to video, discuss the adjustments necessary and the influence of the type of data presented to the networks as well as the number of filters used.

  • 46420. Wyrembelski, Rafael F.
    et al.
    Bjelakovic, Igor
    Oechtering, Tobias J.
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsteori. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Boche, Holger
    Optimal Coding Strategies for Bidirectional Broadcast Channels Under Channel Uncertainty2010Ingår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 58, nr 10, s. 2984-2994Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bidirectional relaying is a promising approach to improve the performance in wireless networks such as sensor, ad-hoc, and even cellular systems. Bidirectional relaying applies to three-node networks, where a relay establishes a bidirectional communication between two other nodes using a decode-and-forward protocol. First, the two nodes transmit their messages to the relay which decodes them. Then, the relay broadcasts a re-encoded message in such a way that both nodes can decode their intended message using their own message as side information. We consider uncertainty in the channel state information (CSI) and assume that all nodes only know that the channel over which the transmission takes place is from a pre-specified set of channels. In this work, we concentrate on the second phase, which is called the compound bidirectional broadcast channel. We present a robust coding strategy which enables reliable communication under channel uncertainty and show that this strategy actually achieves the compound capacity. Further, we analyze scenarios where either the receivers or the transmitter have perfect CSI. We show that CSI at the receivers does not affect the maximal achievable rates, while CSI at the transmitter improves the capacity region. A numerical example and a game-theoretic interpretation complete this work.

  • 46421.
    Wzorek, Mariusz
    Linköpings universitet, Institutionen för datavetenskap, UASTECH – Teknologier för autonoma obemannade flygande farkoster. Linköpings universitet, Tekniska högskolan.
    Selected Aspects of Navigation and Path Planning in Unmanned Aircraft Systems2011Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Unmanned aircraft systems (UASs) are an important future technology with early generations already being used in many areas of application encompassing both military and civilian domains. This thesis proposes a number of integration techniques for combining control-based navigation with more abstract path planning functionality for UASs. These techniques are empirically tested and validated using an RMAX helicopter platform used in the UASTechLab at Linköping University. Although the thesis focuses on helicopter platforms, the techniques are generic in nature and can be used in other robotic systems.

    At the control level a navigation task is executed by a set of control modes. A framework based on the abstraction of hierarchical concurrent state machines for the design and development of hybrid control systems is presented. The framework is used to specify  reactive behaviors and for sequentialisation of control modes. Selected examples of control systems deployed on UASs are presented. Collision-free paths executed at the control level are generated by path planning algorithms.We propose a path replanning framework extending the existing path planners to allow dynamic repair of flight paths when new obstacles or no-fly zones obstructing the current flight path are detected. Additionally, a novel approach to selecting the best path repair strategy based on machine learning technique is presented. A prerequisite for a safe navigation in a real-world environment is an accurate geometrical model. As a step towards building accurate 3D models onboard UASs initial work on the integration of a laser range finder with a helicopter platform is also presented.

    Combination of the techniques presented provides another step towards building comprehensive and robust navigation systems for future UASs.

  • 46422.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Berger, Cyrille
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Doherty, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    A Framework for Safe Navigation of Unmanned Aerial Vehicles in Unknown Environments2017Ingår i: 25th International Conference on Systems Engineering, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a software framework which combines reactive collision avoidance control approach with path planning techniques for the purpose of safe navigation of multiple Unmanned Aerial Vehicles (UAVs) operating in unknown environments. The system proposed leverages advantages of using a fast local sense-and-react type control which guarantees real-time execution with computationally demanding path planning algorithms which generate globally optimal plans. A number of probabilistic path planning algorithms based on Probabilistic Roadmaps and Rapidly- Exploring Random Trees have been integrated. Additionally, the system uses a reactive controller based on Optimal Reciprocal Collision Avoidance (ORCA) for path execution and fast sense-and-avoid behavior. During the mission execution a 3D map representation of the environment is build incrementally and used for path planning. A prototype implementation on a small scale quad-rotor platform has been developed. The UAV used in the experiments was equipped with a structured-light depth sensor to obtain information about the environment in form of occupancy grid map. The system has been tested in a number of simulated missions as well as in real flights and the results of the evaluations are presented. 

  • 46423.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Conte, Gianpaolo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Rudol, Piotr
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Merz, Torsten
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, AUTTEK - Autonomous Unmanned Aerial Vehicle Research Group.
    Duranti, Simone
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, AUTTEK - Autonomous Unmanned Aerial Vehicle Research Group.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    From Motion Planning to Control - A Navigation Framework for an Autonomous Unmanned Aerial Vehicle2006Ingår i: Proceedings of the 21st Bristol UAV Systems Conference (UAVS), 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of Unmanned Aerial Vehicles (UAVs) which can operate autonomously in dynamic and complex operational environments is becoming increasingly more common. While the application domains in which they are currently used are still predominantly military in nature, in the future we can expect wide spread usage in thecivil and commercial sectors. In order to insert such vehicles into commercial airspace, it is inherently important that these vehicles can generate collision-free motion plans and also be able to modify such plans during theirexecution in order to deal with contingencies which arise during the course of operation. In this paper, wepresent a fully deployed autonomous unmanned aerial vehicle, based on a Yamaha RMAX helicopter, whichis capable of navigation in urban environments. We describe a motion planning framework which integrates two sample-based motion planning techniques, Probabilistic Roadmaps and Rapidly Exploring Random Treestogether with a path following controller that is used during path execution. Integrating deliberative services, suchas planners, seamlessly with control components in autonomous architectures is currently one of the major open problems in robotics research. We show how the integration between the motion planning framework and thecontrol kernel is done in our system.

    Additionally, we incorporate a dynamic path reconfigurability scheme. It offers a surprisingly efficient method for dynamic replanning of a motion plan based on unforeseen contingencies which may arise during the execution of a plan. Those contingencies can be inserted via ground operator/UAV interaction to dynamically change UAV flight paths on the fly. The system has been verified through simulation and in actual flight. We present empirical results of the performance of the framework and the path following controller.

  • 46424.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    A framework for reconfigurable path planning for autonomous unmanned aerial vehicles.2007Manuskript (preprint) (Övrig (populärvetenskap, debatt, mm))
  • 46425.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Preliminary report: Reconfigurable path planning for an autonomous unmanned aerial vehicle2005Ingår i: Proceedings of the 24th Annual Workshop of the UK Planning and Scheduling Special Interest Group (PlanSIG), 2005Konferensbidrag (Refereegranskat)
  • 46426.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Reconfigurable Path Planning for an Autonomous Unmanned Aerial Vehicle2006Ingår i: Proceedings of the Sixteenth International Conference on Automated Planning and Scheduling (ICAPS) / [ed] Derek Long, Stephen F. Smith, Daniel Borrajo, Lee McCluskey, AAAI Press, 2006, s. 438-441Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a motion planning framework for a fully deployed autonomous unmanned aerial vehicle which integrates two sample-based motion planning techniques, Probabilistic Roadmaps and Rapidly Exploring Random Trees. Additionally, we incorporate dynamic reconfigurability into the framework by integrating the motion planners with the control kernel of the UAV in a novel manner with little modification to the original algorithms. The framework has been verified through simulation and in actual flight. Empirical results show that these techniques used with such a framework offer a surprisingly efficient method for dynamically reconfiguring a motion plan based on unforeseen contingencies which may arise during the execution of a plan. The framework is generic and can be used for additional platforms.

  • 46427.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Reconfigurable Path Planning for an Autonomous Unmanned Aerial Vehicle2006Ingår i: ICHIT 2006 - International Conference on Hybrid Information Technology,2006, 2006Konferensbidrag (Refereegranskat)
  • 46428.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Reconfigurable path planning for an autonomous unmanned aerial vehicle2005Ingår i: National Swedish Workshop on Autonomous Systems, SWAR 05,2005, 2005Konferensbidrag (Refereegranskat)
  • 46429.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    The WITAS UAV Ground System Interface Demonstration with a Focus on Motion and Task Planning2006Ingår i: Software Demonstrations at the International Conference on Automated Planning Scheduling (ICAPS-SD), 2006, s. 36-37Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The Autonomous UAV Technologies Laboratory at Linköping University, Sweden, has been developing fully autonomous rotor-based UAV systems in the mini- and micro-UAV class. Our current system design is the result of an evolutionary process based on many years of developing, testing and maintaining sophisticated UAV systems. In particular, we have used the Yamaha RMAX helicopter platform(Fig. 1) and developed a number of micro air vehicles from scratch.

  • 46430.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Institutionen för datavetenskap, UASTECH – Teknologier för autonoma obemannade flygande farkoster. Linköpings universitet, Tekniska högskolan.
    Kvarnström, Jonas
    Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning. Linköpings universitet, Tekniska högskolan.
    Doherty, Patrick
    Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning. Linköpings universitet, Institutionen för datavetenskap, UASTECH – Teknologier för autonoma obemannade flygande farkoster. Linköpings universitet, Tekniska högskolan.
    Choosing Path Replanning Strategies for Unmanned Aircraft Systems2010Ingår i: Proceedings of the Twentieth International Conference on Automated Planning and Scheduling (ICAPS) / [ed] Ronen Brafman, Héctor Geffner, Jörg Hoffmann, Henry Kautz, Toronto, Canada: AAAI Press , 2010, s. 193-200Konferensbidrag (Refereegranskat)
    Abstract [en]

    Unmanned aircraft systems use a variety of techniques to plan collision-free flight paths given a map of obstacles and no- fly zones. However, maps are not perfect and obstacles may change over time or be detected during flight, which may in- validate paths that the aircraft is already following. Thus, dynamic in-flight replanning is required.Numerous strategies can be used for replanning, where the time requirements and the plan quality associated with each strategy depend on the environment around the original flight path. In this paper, we investigate the use of machine learn- ing techniques, in particular support vector machines, to choose the best possible replanning strategy depending on the amount of time available. The system has been implemented, integrated and tested in hardware-in-the-loop simulation with a Yamaha RMAX helicopter platform.

  • 46431.
    Wzorek, Mariusz
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Landén, David
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    Doherty, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning.
    GSM Technology as a Communication Media for an Autonomous Unmanned Aerial Vehicle2006Ingår i: Proceedings of the 21st Bristol International UAV Systems Conference (UAVS), Bristol: University of Bristol, Department of Aerospace engineering , 2006Konferensbidrag (Refereegranskat)
  • 46432.
    Wächter, Thomas
    et al.
    TU Dresden.
    Tan, He
    (Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems.
    Wobst, André
    TU Dresden.
    Lambrix, Patrick
    (Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems.
    Schroeder, Michael
    TU Dresden.
    A Corpus-driven Approach for Design, Evolution and Alignment of Ontologies2006Ingår i: Proceedings of the Winter Simulation Conference, 2006, WSC 06, 2006, s. 1595-1602Konferensbidrag (Refereegranskat)
    Abstract [en]

    Bio-ontologies are hierarchical vocabularies, which are used to annotate other data sources such as sequence and structure databases. With the wide use of ontologies their integration, design, and evolution becomes an important problem. We show how textmining on relevant text corpora can be used to identify matching ontology terms of two separate ontologies and to propose new ontology terms for a given term. We evaluate these approaches on the GeneOntology

  • 46433.
    Wächter, Thomas
    et al.
    Biotechnologisches Zentrum, TU Dresden, Germany.
    Tan, He
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Wobst, André
    Biotechnologisches Zentrum, TU Dresden, Germany.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Schroeder, Michael
    Biotechnologisches Zentrum, TU Dresden, Germany.
    A Corpus-driven Approach for Design, Evolution and Alignment of Ontologies2006Ingår i: Winter Simulation Conference,2006, 2006, s. 1595-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Bio-ontologies are hierarchical vocabularies, which are used to annotate other data sources such as sequence and structure databases. With the wide use of ontologies their integration, design, and evolution becomes an important problem. We show how textmining on relevant text corpora can be used to identify matching ontology terms of two separate ontologies and to propose new ontology terms for a given term. We evaluate these approaches on the GeneOntology.

  • 46434.
    Wählby, Carolina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Algorithms for Applied Digital Image Cytometry2003Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Image analysis can provide genetic as well as protein level information from fluorescence stained fixed or living cells without loosing tissue morphology. Analysis of spatial, spectral, and temporal distribution of fluorescence can reveal important information on the single cell level. This is in contrast to most other methods for cell analysis, which do not account for inter-cellular variation. Flow cytometry enables single-cell analysis, but tissue morphology is lost in the process, and temporal events cannot be observed.

    The need for reproducibility, speed and accuracy calls for computerized methods for cell image analysis, i.e., digital image cytometry, which is the topic of this thesis.

    Algorithms for cell-based screening are presented and applied to evaluate the effect of insulin on translocation events in single cells. This type of algorithms could be the basis for high-throughput drug screening systems, and have been developed in close cooperation with biomedical industry.

    Image based studies of cell cycle proteins in cultured cells and tissue sections show that cyclin A has a well preserved expression pattern while the expression pattern of cyclin E is disturbed in tumors. The results indicate that analysis of cyclin E expression provides additional valuable information for cancer prognosis, not visible by standard tumor grading techniques.

    Complex chains of events and interactions can be visualized by simultaneous staining of different proteins involved in a process. A combination of image analysis and staining procedures that allow sequential staining and visualization of large numbers of different antigens in single cells is presented. Preliminary results show that at least six different antigens can be stained in the same set of cells.

    All image cytometry requires robust segmentation techniques. Clustered objects, background variation, as well as internal intensity variations complicate the segmentation of cells in tissue. Algorithms for segmentation of 2D and 3D images of cell nuclei in tissue by combining intensity, shape, and gradient information are presented.

    The algorithms and applications presented show that fast, robust, and automatic digital image cytometry can increase the throughput and power of image based single cell analysis.

  • 46435.
    Wählby, Carolina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    High throughput phenotyping of model organisms2012Ingår i: BioImage Informatics 2012 / [ed] Fuhui Long, Ivo F. Sbalzarini, Pavel Tomancak and Michael Unser, Dresden, Germany, 2012, s. 45-45Konferensbidrag (Refereegranskat)
    Abstract [en]

    Microscopy has emerged as one of the most powerful and informative ways to analyze cell-based high-throughput screening samples in experiments designed to uncover novel drugs and drug targets. However, many diseases and biological pathways can be better studied in whole animals – particularly diseases that involve organ systems and multi-cellular interactions, such as metabolism, infection, vascularization, and development. Two model organisms compatible with high-throughput phenotyping are the 1mm long round worm C. elegans and the transparent embryo of zebrafish (Danio rerio). C. elegans is tractable as it can be handled using similar robotics, multi-well plates, and flow-sorting systems as are used for high-throughput screening of cells. The worm is also transparent throughout its lifecycle and is attractive as a model for genetic functions as its genes can be turned off by RNA-interference. Zebrafish embryos have also proved to be a vital model organism in many fields of research, including organismal development, cancer, and neurobiology. Zebrafish, being vertebrates, exhibit features common to phylogenetically higher organisms such as a true vasculature and central nervous system.

     

    Basically any phenotypic change that can be visually observed (in untreated or stained worms and fish) can also be imaged. However, visual assessment of phenotypic variation is tedious and prone to error as well as observer bias. Screening in high throughput limits image resolution and time-lapse information. Still, the images are typically rich in information and the number of images for a standard screen often exceeds 100 000, ruling out visual inspection. Generation of automated image analysis platforms will increase the throughout of data analysis, improve the robustness of phenotype scoring, and allow for reliable application of statistical metrics for evaluating assay performance and identifying active compounds.

     

    We have developed a platform for automated analysis of C. elegans assays, and are currently developing tools for analysis of zebrafish embryos. Our worm analysis tools, collected in the WormToolbox, can identify individual worms also as they cross and overlap, and quantify a large number of features, including mapping of reporter protein expression patterns to the worm anatomy. We have evaluated the tools on screens for novel treatments of infectious disease and genetic perturbations affecting fat metabolism. The WormToolbox is part of the free and open source CellProfiler software, also including methods for image assay quality control and feature selection by machine learning.

  • 46436.
    Wählby, Carolina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Image analysis in fluorescence microscopy: the human eye is not enough2008Ingår i: Medicinteknikdagar 2008: Mötesplats för aktörer inom forskning, sjukvård och industri, Proceedings, Medicinteknikdagarna 2008: Nils Löfgren, Högskolan i Borås , 2008Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

     

     

     

  • 46437.
    Wählby, Carolina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Image Segmentation, Processing and Analysis in Microscopy and Life Science2015Ingår i: Mathematical Models in Biology: Bringing Mathematics to Life, Springer, 2015, s. 1-16Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 46438.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Segmentation of cell nuclei in tissue by combining seeded watersheds with gradient information2003Ingår i: Proceedings of SCIA-03: Scandinavian Conference on Image Analysis, 2003, s. 408-414Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with the segmentation of cell nuclei in tissue. We present a region-based segmentation method where seeds representing object- and background-pixels are created by morphological filtering. The seeds are then used as a starting point for watershed segmentation of the gradient magnitude of the original image. Over-segmented objects are thereafter merged based on the gradient magnitude between the adjacent objects. The method was tested on a total of 726 cell nuclei in 7 images, and 95% correct segmentation was achieved.

  • 46439.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Watershed techniques for segmentation in image cytometry2003Ingår i: Proceedings of the 1st International Cytomics Conference: Newport, Wales, United Kingdom, 2003Konferensbidrag (Övrigt vetenskapligt)
  • 46440.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Erlandsson, Fredrik
    Bengtsson, Ewert
    Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Zetterberg, Anders
    Sequential immunofluorescence staining and image analysis for detection of large numbers of antigens in individual cell nuclei2002Ingår i: Cytometry, ISSN 0196-4763, Vol. 47, nr 1, s. 32-41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background

    Visualization of more than one antigen by multicolor immunostaining is often desirable or even necessary to explore spatial and temporal relationships of functional significance. Previously presented staining protocols have been limited to the visualization of three or four antigens.

    Methods

    Immunofluorescence staining was performed both on slices of formalin-fixed tissue and on cells microscopy. The primary and secondary antibodies, as well as the fluorophores, were thereafter removed using a combination of denaturation and elution techniques. After removal of the fluorescence stain, a new immunofluorescence staining was performed, visualizing a new set of antigens. The procedure was repeated up to three times. A method for image registration combined with segmentation, extraction of data, and cell classification was developed for efficient and objective analysis of the image data.

    Results

    The results show that immunofluorescence stains in many cases can be repeatedly removed without major effects on the antigenicity of the sample.

    Conclusions

    The concentration of at least six different antigens in each cell can thus be measured semiquantitatively using sequential immunofluorescence staining and the described image analysis techniques. The number of antigens that can be visualized in a single sample is considerably increased by the presented protocol.

  • 46441.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Erlandsson, Fredrik
    Lindblad, Joakim
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Zetterberg, Anders
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Analysis of cells using image data from sequential immunofluorescence staining experiments2001Ingår i: 5th Korea-Germany Joint Workshop on Advanced Medical Image Processing, Seoul, Korea, 2001Konferensbidrag (Övrigt vetenskapligt)
  • 46442.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Erlandsson, Fredrik
    Nyberg, Karl
    Lindblad, Joakim
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Zetterberg, Anders
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Multiple tissue antigen analysis by sequential immunofluorescence staining and multi-dimensional image analysis2001Ingår i: Proceedings of SCIA-01 (Scandinavian Conference on Image Analysis), 2001, s. 25-31Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a novel method for sequential immunofluorescence staining, which, in combination with 3D image registration and segmentation, can be used to increase the number of antigens that can be observed simultaneously in single cells in tissue sections. Visualization of more than one antigen by multicolor immunostaining is often desirable or even necessary, both for quantitative studies and to explore spatial relationships of functional significance. Sequential staining, meaning repeated application and removal of fluorescence markers, greatly increases the number of different antigens that can be visualized and quantified in single cells using digital imaging fluorescence microscopy. Quantification and efficient objective analysis of the image data requires digital image analysis. A method for 3D image registration combined with 2D and 3D segmentation and 4D extraction of data is described.

  • 46443.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Erlandsson, Fredrik
    Zetterberg, Anders
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Multi-dimensional image analysis of sequential immunofluorescence staining2001Ingår i: 7th European Society for Analytical Cellular Pathology Congress (ESACP 2001), Caen, France, 2001, s. 61-Konferensbidrag (Övrigt vetenskapligt)
  • 46444.
    Wählby, Carolina
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Karlsson, Patrick
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Henriksson, Sara
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Larsson, Chatarina
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Nilsson, Mats
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Bengtsson, Ewert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Finding cells, finding molecules, finding patterns2006Ingår i: Advances in Data Mining: Workshop on Mass-Data Analysis of Images and Signals in Medicine, Biotechnology and Chemistry, MDA´2006, Leipzig/Germany, 2006, s. 15-24Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many modern molecular labeling techniques result in bright point signals. Signals from molecules that are detected directly inside a cell can be captured by fluorescence microscopy. Signals representing different types of molecules may be randomly distributed in the cells or show systematic patterns indicating that the corresponding molecules have specific, non-random localizations and functions in the cell. Assessing this information requires high speed robust image segmentation followed by signal detection, and finally pattern analysis. We present and discuss this type of methods and show an example of how the distribution of different variants of mitochondrial DNA can be analyzed.

  • 46445.
    Wählby, Carolina
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Karlsson, Patrick
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Henriksson, Sara
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Larsson, Chatarina
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Nilsson, Mats
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Bengtsson, Ewert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Finding cells, finding molecules, finding patterns2008Ingår i: International Journal of Signal and Imaging Systems Engineering, ISSN 1748-0698, Vol. 1, nr 1, s. 11-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many modern molecular labelling techniques result in bright point signals. Signals from molecules that are detected directly inside a cell can be captured by fluorescence microscopy. Signals representing different types of molecules may be randomly distributed in the cells or show systematic patterns, indicating that the corresponding molecules have specific, non-random localisations and functions in the cell. Assessing this information requires high speed robust image segmentation followed by signal detection, and finally, pattern analysis. We present and discuss these types of methods and show an example of how the distribution of different variants of mitochondrial DNA can be analysed.

  • 46446.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Karlsson, Patrick
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Thorlin, Thorleif
    Althoff, Karin
    Degerman, Johan
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Gustavsson, Tomas
    Time-lapse microscopy and image analysis for tracking stem cell migration2004Ingår i: Proceedings of the Swedish Symposium on Image Analysis SSBA 2004, 2004, s. 118-121Konferensbidrag (Övrigt vetenskapligt)
  • 46447.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Lindblad, Joakim
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Vondrus, Mikael
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Björkesten, Lennart
    Algorithms for cytoplasm segmentation of fluorescence labeled cells.2002Ingår i: Analytical Cellular Pathology, ISSN 09218912, Vol. 24, nr 2,3, s. 101-111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Automatic cell segmentation has various applications in cytometry, and while the nucleus is often very distinct and easy to identify, the cytoplasm provides a lot more challenge. A new combination of image analysis algorithms for segmentation of cells imaged by fluorescence microscopy is presented. The algorithm consists of an image pre-processing step, a general segmentation and merging step followed by a segmentation quality measurement. The quality measurement consists of a statistical analysis of a number of shape descriptive features. Objects that have features that differ to that of correctly segmented single cells can be further processed by a splitting step. By statistical analysis we therefore get a feedback system for separation of clustered cells. After the segmentation is completed, the quality of the final segmentation is evaluated. By training the algorithm on a representative set of training images, the algorithm is made fully automatic for subsequent images created under similar conditions. Automatic cytoplasm segmentation was tested on CHO-cells stained with calcein. The fully automatic method showed between 89% and 97% correct segmentation as compared to manual segmentation.

  • 46448.
    Wählby, Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Nyström, Ingela
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Robust methods for image segmentation and measurements.2003Ingår i: Proceedings for Modern Methods for Quantitative Metallography, 2003Konferensbidrag (Refereegranskat)
  • 46449.
    Wählby, Carolina
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Sintorn, Ida-Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Erlandsson, Fredrik
    Borgefors, Gunilla
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Combining intensity, edge, and shape information for 2D and 3D segmentation of cell nuclei in tissue sections2004Ingår i: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 215, nr 1, s. 67-76Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a region-based segmentation method in which seeds representing both object and background pixels are created by combining morphological filtering of both the original image and the gradient magnitude of the image. The seeds are then used as starting points for watershed segmentation of the gradient magnitude image. The fully automatic seeding is done in a generous fashion, so that at least one seed will be set in each foreground object. If more than one seed is placed in a single object, the watershed segmentation will lead to an initial over-segmentation, i.e. a boundary is created where there is no strong edge. Thus, the result of the initial segmentation is further refined by merging based on the gradient magnitude along the boundary separating neighbouring objects. This step also makes it easy to remove objects with poor contrast. As a final step, clusters of nuclei are separated, based on the shape of the cluster. The number of input parameters to the full segmentation procedure is only five. These parameters can be set manually using a test image and thereafter be used on a large number of images created under similar imaging conditions. This automated system was verified by comparison with manual counts from the same image fields. About 90% correct segmentation was achieved for two- as well as three-dimensional images.

  • 46450.
    Wählby (née Linnman), Carolina
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Lindblad, Joakim
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Vondrus, Mikael
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Jarkrans, Torsten
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Björkesten, Lennart
    Automatic cytoplasm segmentation of fluorescence labelled cells2000Ingår i: Symposium on Image Analysis - SSAB 2000, 2000, s. 29-32Konferensbidrag (Övrigt vetenskapligt)
926927928929930931932 46401 - 46450 av 48265
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