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  • 51.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez, J.
    Universidad Autonoma de Madrid, Spain.
    Gilperez, A.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    Impact of time variability in off-line writer identification and verification2009Ingår i: ISPA 2009: Proceedings of the 6th International Symposium on Image and Signal Processing and Analysis, Piscataway, N.J.: IEEE Press, 2009, s. 540-545Konferensbidrag (Refereegranskat)
    Abstract [en]

    One of the biggest challenges in person recognition using biometric systems is the variability in the acquired data. In this paper, we evaluate the effects of an increasing time lapse between reference and test biometric data consisting of static images of handwritten signatures and texts. We use for our experiments two recognition approaches exploiting information at the global and local levels, and the BiosecurlD database, containing 3,724 signature images and 532 texts of 133 individuals acquired in four acquisition sessions distributed along a 4 months time span. We report results of the recognition systems working both in verification (one-to-one) and identification (one-to-many) mode. The results show the extent of the impact that the time separation between samples under comparison has on the recognition rates, being the local approach more robust to the time lapse than the global one. We also observe in our experiments that recognition based on handwritten texts provides higher accuracy than recognition based on signatures.

  • 52.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez, J.
    Universidad Autonoma de Madrid, Spain.
    Martinez-Diaz, M.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    Fusion of static image and dynamic information for signature verification2009Ingår i: ICIP 2009: 2009 IEEE International Conference on Image Processing : proceedings, November 7-12, 2009, Cairo, Egypt, Piscataway, N.J.: IEEE Press, 2009, s. 2725-2728Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper evaluates the combination of static image (off-line) and dynamic information (on-line) for signature verification. Two off-line and two on-line recognition approaches exploiting information at the global and local levels are used. Experimental results are given using the BiosecurID database (130 signers, 3,640 signatures). Fusion experiments are done using a trained fusion approach based on linear logistic regression. It is shown experimentally that the local systems outperform the global ones, both in the on-line and in the off-line case. We also observe a considerable improvement when combining the two on-line systems, which is not the case with the off-line systems. The best performance is obtained when fusing all the systems together, which is specially evident for skilled forgeries when enough training data is available. ©2009 IEEE.

  • 53.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez, J.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    An enhanced Gabor filter-based segmentation algorithm for fingerprint recognition systems2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    An imponant step in fingerprint recognition is the segmentation of the region of interest. In this paper, we present an enhanced approach for fingerprint segmentation based on the response of eight oriented Gabor filters. The performance of the algorithm has been evaluated in terms of decision error trade-off curves of an overall verification system. Experimental results demonstrate the robustness of the proposed method.

  • 54.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ramos, D.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Dealing With Sensor Interoperability in Multi-biometrics: The UPM Experience at the Biosecure Multimodal Evaluation 20072008Ingår i: Biometric Technology for Human Identification, Bellingham, WA: SPIE - International Society for Optical Engineering, 2008, Vol. 6944, s. J9440-J9440Konferensbidrag (Refereegranskat)
    Abstract [en]

    Multimodal biometric systems allow to overcome some of the problems presented in unimodal systems, such as non-universality, lack of distinctiveness of the unimodal trait, noise in the acquired data, etc. Integration at the matching score level is the most common approach used due to the ease in combining the scores generated by different unimodal systems. Unfortunately, scores usually lie in application-dependent domains. In this work, we use linear logistic regression fusion, in which fused scores tend to be calibrated log-likelihood-ratios and thus, independent of the application. We use for our experiments the development set of scores of the DS2 Evaluation (Access Control Scenario) of the BioSecure Multimodal Evaluation Campaign, whose objective is to compare the performance of fusion algorithms when query biometric signals are originated from heterogeneous biometric devices. We compare a fusion scheme that uses linear logistic regression with a set of simple fusion rules. It is observed that the proposed fusion scheme outperforms all the simple fusion rules, with the additional advantage of the application-independent nature of the resulting fused scores.

  • 55.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Laboratoriet för intelligenta system.
    Fierrez, Julian
    Universidad Autonoma de Madrid, Madrid, Spain.
    Fingerprint Databases and Evaluation2015Ingår i: Encyclopedia of Biometrics / [ed] Stan Z. Li & Anil K. Jain, New York: Springer Science+Business Media B.V., 2015, 2, s. 599-606Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This is an excerpt from the content

    Synonyms

    Fingerprint benchmark; Fingerprint corpora; Fingerprint dataset

    Definition

    Fingerprint databases are structured collections of fingerprint data mainly used for either evaluation or operational recognition purposes.

    Fingerprint data in databases for evaluation are usually detached from the identity of corresponding individuals. These databases are publicly available for research purposes, and they usually consist of raw fingerprint images acquired with live-scan sensors or digitized from inked fingerprint impressions on paper. Databases for evaluation are the basis for research in automatic fingerprint recognition, and together with specific experimental protocols, they are the basis for a number of technology evaluations and benchmarks. This is the type of fingerprint databases further covered here.

    On the other hand, fingerprint databases for operational recognition are typically proprietary, they usually incorporate personal information about the enrolled people together with the fingerprint data, and they can incorporate either raw fingerprint image data or some form of distinctive fingerprint descriptors such as minutiae templates. These fingerprint databases represent one of the modules in operational automated fingerprint recognition systems, and they will not be adressed here.

  • 56.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Laboratoriet för intelligenta system.
    Fierrez, Julian
    Universidad Autonoma de Madrid, Madrid, Spain.
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Quality Measures in Biometric Systems2015Ingår i: Encyclopedia of Biometrics / [ed] Stan Z. Li & Anil K. Jain, New York: Springer Science+Business Media B.V., 2015, 2, s. 1287-1297Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This is an excerpt from the content

    Synonyms

    Quality assessment; Biometric quality; Quality-based processing

    Definition

    Since the establishment of biometrics as a specific research area in the late 1990s, the biometric community has focused its efforts in the development of accurate recognition algorithms [1]. Nowadays, biometric recognition is a mature technology that is used in many applications, offering greater security and convenience than traditional methods of personal recognition [2].

    During the past few years, biometric quality measurement has become an important concern after a number of studies and technology benchmarks that demonstrate how performance of biometric systems is heavily affected by the quality of biometric signals [3]. This operationally important step has been nevertheless under-researched compared to the primary feature extraction and pattern recognition tasks [4]. One of the main challenges facing biometric technologies is performance degradation in less controlled situations, and the problem of biometric quality measurement has arisen even stronger with the proliferation of portable handheld devices, with at-a-distance and on-the-move acquisition capabilities. These will require robust algorithms capable of handling a range of changing characteristics [2]. Another important example is forensics, in which intrinsic operational factors further degrade recognition performance.

    There are number of factors that can affect the quality of biometric signals, and there are numerous roles of a quality measure in the context of biometric systems. This section summarizes the state of the art in the biometric quality problem, giving an overall framework of the different challenges involved.

  • 57.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Laboratoriet för intelligenta system. Fernando.Alonso-Fernandez@hh.se.
    Fierrez, Julian
    Universidad Autonoma de Madrid, Madrid, Spain.
    Ortega-Garcia, Javier
    Universidad Autonoma de Madrid, Madrid, Spain.
    Quality Measures in Biometric Systems2012Ingår i: IEEE Security and Privacy, ISSN 1540-7993, E-ISSN 1558-4046, Vol. 10, nr 6, s. 52-62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biometric technology has been increasingly deployed in the last decade, offering greater security and convenience than traditional methods of personal recognition. But although the performance of biometric systems is heavily affected by the quality of biometric signals, prior work on quality evaluation is limited. Quality assessment is a critical issue in the security arena, especially in challenging scenarios (e.g. surveillance cameras, forensics, portable devices or remote access through Internet). Different questions regarding the factors influencing biometric quality and how to overcome them, or the incorporation of quality measures in the context of biometric systems have to be analyzed first. In this paper, a review of the state-of-the-art in these matters is provided, giving an overall framework of the main factors related to the challenges associated with biometric quality.

  • 58.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez, Julian
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ramos, Daniel
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Gonzalez-Rodriguez, Joaquin
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Quality-Based Conditional Processing in Multi-Biometrics: Application to Sensor Interoperability2010Ingår i: IEEE transactions on systems, man and cybernetics. Part A. Systems and humans, ISSN 1083-4427, E-ISSN 1558-2426, Vol. 40, nr 6, s. 1168-1179Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As biometric technology is increasingly deployed, it will be common to replace parts of operational systems with newer designs. The cost and inconvenience of reacquiring enrolled users when a new vendor solution is incorporated makes this approach difficult and many applications will require to deal with information from different sources regularly. These interoperability problems can dramatically affect the performance of biometric systems and thus, they need to be overcome. Here, we describe and evaluate the ATVS-UAM fusion approach submitted to the quality-based evaluation of the 2007 BioSecure Multimodal Evaluation Campaign, whose aim was to compare fusion algorithms when biometric signals were generated using several biometric devices in mismatched conditions. Quality measures from the raw biometric data are available to allow system adjustment to changing quality conditions due to device changes. This system adjustment is referred to as quality-based conditional processing. The proposed fusion approach is based on linear logistic regression, in which fused scores tend to be log-likelihood-ratios. This allows the easy and efficient combination of matching scores from different devices assuming low dependence among modalities. In our system, quality information is used to switch between different system modules depending on the data source (the sensor in our case) and to reject channels with low quality data during the fusion. We compare our fusion approach to a set of rule-based fusion schemes over normalized scores. Results show that the proposed approach outperforms all the rule-based fusion schemes. We also show that with the quality-based channel rejection scheme, an overall improvement of 25% in the equal error rate is obtained. © 2010 IEEE.

  • 59.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez-Aguilar, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    del-Valle, F.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    On-line signature verification using Tablet PC2005Ingår i: Proceedings of the 4th International Symposium on Image and Signal Processing and Analysis: Zagreb, Croatia, 15 - 17 September, 2005, Zagreb: University of Zagreb , 2005, s. 245-250Konferensbidrag (Refereegranskat)
    Abstract [en]

    On-line signature verification for Tablet PC devices is studied. The on-line signature verification algorithm presented by the authors at the First International Signature Verification Competition (SVC 2004) is adapted to work in Tablet PC environments. An example prototype of securing access and securing document application using this Tablet PC system is also reported. Two different commercial Tablet PCs are evaluated, including information of interest for signature verification systems such as sampling and pressure statistics. Authentication performance experiments are reported considering both random and skilled forgeries by using a new database with over 3000 signatures.

  • 60.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez-Aguilar, J.
    Universidad Autonoma de Madrid, Spain.
    Galbally, J.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    Exploiting Character Class Information in Forensic Writer Identification2011Ingår i: Computational forensics: 4th International Workshop, IWCF 2010 Tokyo, Japan, November 11-12, 2010 : revised selected papers, Berlin: Springer Berlin/Heidelberg, 2011, s. 31-42Konferensbidrag (Refereegranskat)
    Abstract [en]

    Questioned document examination is extensively used by forensic specialists for criminal identification. This paper presents a writer recognition system based on contour features operating in identification mode (one-to-many) and working at the level of isolated characters. Individual characters of a writer are manually segmented and labeled by an expert as pertaining to one of 62 alphanumeric classes (10 numbers and 52 letters, including lowercase and uppercase letters), being the particular setup used by the forensic laboratory participating in this work. Three different scenarios for identity modeling are proposed, making use to a different degree of the class information provided by the alphanumeric samples. Results obtained on a database of 30 writers from real forensic documents show that the character class information given by the manual analysis provides a valuable source of improvement, justifying the significant amount of time spent in manual segmentation and labeling by the forensic specialist. © 2011 Springer-Verlag Berlin Heidelberg.

  • 61.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez-Aguilar, J.
    Universidad Autonoma de Madrid, Spain.
    Gilperez, A.
    Universidad Autonoma de Madrid, Spain.
    Galbally, J.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    Robustness of signature verification systems to imitators with increasing skills2009Ingår i: ICDAR '09: Proceedings of the 10th International Conference on Document Analysis and Recognition, 26-29 July 2009, Barcelona, Catalonia, Spain, Los Alamitos, Calif.: IEEE Computer Society, 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we study the impact of an incremental level of skill in the forgeries against signature verification systems. Experiments are carried out using both off-line systems, involving the discrimination of signatures written on a piece of paper, and on-line systems, in which dynamic information of the signing process (such as velocity and acceleration) is also available. We use for our experiments the BiosecurID database, which contains both on-line and off-line versions of signatures, acquired in four sessions across a 4 month time span with incremental level of skill in the forgeries for different sessions. We compare several scenarios with different size and variability of the enrolment set, showing that the problem of skilled forgeries can be alleviated as we consider more signatures for enrolment. © 2009 IEEE.

  • 62.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez-Aguilar, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Sensor interoperability and fusion in signature verification: a case study using Tablet PC2005Ingår i: Advances in biometric person authentification: International workshop on biometric recognition systems, IWBRS 2005, Beijing, China, October 22-23, 2005 : proceedings, New York: Springer-Verlag New York, 2005, Vol. Springer LNCS-3781, s. 180-187Konferensbidrag (Refereegranskat)
    Abstract [en]

    Several works related to information fusion for signature verification have been presented. However, few works have focused on sensor fusion and sensor interoperability. In this paper, these two topics are evaluated for signature verification using two different commercial Tablet PCs. An enrolment strategy using signatures from the two Tablet PCs is also proposed. Authentication performance experiments are reported by using a database with over 3000 signatures. © Springer-Verlag Berlin Heidelberg 2005.

  • 63.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Fierrez-Aguilar, J.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    Gonzalez-Rodriguez, J.
    Universidad Autonoma de Madrid, Spain.
    Secure access system using signature verification over Tablet PC2007Ingår i: IEEE Aerospace and Electronic Systems Magazine, ISSN 0885-8985, E-ISSN 1557-959X, Vol. 22, nr 4, s. 3-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low-cost portable devices capable of capturing signature signals are being increasingly used. Additionally, the social and legal acceptance of the written signature for authentication purposes is opening a range of new applications. We describe a highly versatile and scalable prototype for Web-based secure access using signature verification. The proposed architecture can be easily extended to work with different kinds of sensors and large-scale databases. Several remarks are also given on security and privacy of network-based signature verification. © 2007 IEEE.

  • 64.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Madrid, Spain.
    Fierrez-Aguilar, Julian
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Madrid, Spain.
    Ortega-Garcia, Javier
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Madrid, Spain.
    A Review Of Schemes For Fingerprint Image Quality Computation2005Ingår i: COST Action 275: Proceedings of the third COST 275 Workshop Biometrics on the Internet / [ed] Aladdin Ariyaeeinia, Mauro Falcone & Andrea Paoloni, Luxembourg: EU Publications Office (OPOCE) , 2005, s. 3-6Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fingerprint image quality affects heavily the performance of fingerprint recognition systems. This paper reviews existing approaches for fingerprint image quality computation. We also implement, test and compare a selection of them using the MCYT database including 9000 fingerprint images. Experimental results show that most of the algorithms behave similarly.

  • 65.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Mikaelyan, Anna
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Compact Multi-scale Periocular Recognition Using SAFE Features2016Ingår i: Proceedings - International Conference on Pattern Recognition, Washington: IEEE Communications Society, 2016, s. 1455-1460, artikel-id 7899842Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a new approach for periocular recognition based on the Symmetry Assessment by Feature Expansion (SAFE) descriptor, which encodes the presence of various symmetric curve families around image key points. We use the sclera center as single key point for feature extraction, highlighting the object-like identity properties that concentrates to this unique point of the eye. As it is demonstrated, such discriminative properties can be encoded with a reduced set of symmetric curves. Experiments are done with a database of periocular images captured with a digital camera. We test our system against reference periocular features, achieving top performance with a considerably smaller feature vector (given by the use of a single key point). All the systems tested also show a nearly steady correlation between acquisition distance and performance, and they are also able to cope well when enrolment and test images are not captured at the same distance. Fusion experiments among the available systems are also provided. © 2016 IEEE

  • 66.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Mikaelyan, Anna
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Comparison and Fusion of Multiple Iris and Periocular Matchers Using Near-Infrared and Visible Images2015Ingår i: 3rd International Workshop on Biometrics and Forensics, IWBF 2015, Piscataway, NJ: IEEE Press, 2015, s. Article number: 7110234-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Periocular refers to the facial region in the eye vicinity. It can be easily obtained with existing face and iris setups, and it appears in iris images, so its fusion with the iris texture has a potential to improve the overall recognition. It is also suggested that iris is more suited to near-infrared (NIR) illu- mination, whereas the periocular modality is best for visible (VW) illumination. Here, we evaluate three periocular and three iris matchers based on different features. As experimen- tal data, we use five databases, three acquired with a close-up NIR camera, and two in VW light with a webcam and a dig- ital camera. We observe that the iris matchers perform better than the periocular matchers with NIR data, and the opposite with VW data. However, in both cases, their fusion can pro- vide additional performance improvements. This is specially relevant with VW data, where the iris matchers perform sig- nificantly worse (due to low resolution), but they are still able to complement the periocular modality. © 2015 IEEE.

  • 67.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Raja, Kiran B.
    Norwegian University of Science and Technology, Gjøvik, Norway.
    Busch, Christoph
    Norwegian University of Science and Technology, Gjøvik, Norway.
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Log-Likelihood Score Level Fusion for Improved Cross-Sensor Smartphone Periocular Recognition2017Ingår i: 2017 25th European Signal Processing Conference (EUSIPCO), Piscataway: IEEE, 2017, s. 281-285, artikel-id 8081211Konferensbidrag (Refereegranskat)
    Abstract [en]

    The proliferation of cameras and personal devices results in a wide variability of imaging conditions, producing large intra-class variations and a significant performance drop when images from heterogeneous environments are compared. However, many applications require to deal with data from different sources regularly, thus needing to overcome these interoperability problems. Here, we employ fusion of several comparators to improve periocular performance when images from different smartphones are compared. We use a probabilistic fusion framework based on linear logistic regression, in which fused scores tend to be log-likelihood ratios, obtaining a reduction in cross-sensor EER of up to 40% due to the fusion. Our framework also provides an elegant and simple solution to handle signals from different devices, since same-sensor and crosssensor score distributions are aligned and mapped to a common probabilistic domain. This allows the use of Bayes thresholds for optimal decision making, eliminating the need of sensor-specific thresholds, which is essential in operational conditions because the threshold setting critically determines the accuracy of the authentication process in many applications. © EURASIP 2017

  • 68.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Roli, F.
    University of Cagliari, Italy.
    Marcialis, G. L.
    University of Cagliari, Italy.
    Fierrez, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Comparison of fingerprint quality measures using an optical and a capacitive sensor2007Ingår i: Biometrics: Theory, Applications, and Systems, 2007. BTAS 2007. First IEEE International Conference on, Piscataway, N.J.: IEEE Press, 2007, s. 133-138Konferensbidrag (Refereegranskat)
    Abstract [en]

    Although several image quality measures have been proposed for fingerprints, no work has taken into account the differences among capture devices, and how these differences impact on the image quality. In this paper, several representative measures for assessing the quality fingerprint images are compared using an optical and a capacitive sensor. The capability to discriminate between images of different quality and its relationship with the verification performance is studied. We report differences depending on the sensor, and interesting relationships between sensor technology and features used for quality assessment are also pointed out. ©2007 IEEE.

  • 69.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Roli, Fabio
    Marcialis, Gian Luca
    Fierrez, Julian
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, Javier
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Performance of Fingerprint Quality Measures Depending on Sensor Technology2008Ingår i: Journal of Electronic Imaging (JEI), ISSN 1017-9909, E-ISSN 1560-229X, Vol. 17, nr 1Artikel i tidskrift (Refereegranskat)
  • 70.
    Alonso-Fernandez, Fernando
    et al.
    Univ Autonoma Madrid, Escuela Politecn Super, Biometr Recognit Grp ATVS, E-28049 Madrid, Spain.
    Roli, Fabio
    University of Cagliari, Department of Electrical and Electronic Engineering, Piazza d'Armi, 09123 Cagliari, Italy.
    Marcialis, Gian Luca
    University of Cagliari, Department of Electrical and Electronic Engineering, Piazza d'Armi, 09123 Cagliari, Italy.
    Fierrez, Julian
    Univ Autonoma Madrid, Escuela Politecn Super, Biometr Recognit Grp ATVS, E-28049 Madrid, Spain.
    Ortega-Garcia, Javier
    Univ Autonoma Madrid, Escuela Politecn Super, Biometr Recognit Grp ATVS, E-28049 Madrid, Spain.
    Gonzalez-Rodriguez, Joaquin
    Univ Autonoma Madrid, Escuela Politecn Super, Biometr Recognit Grp ATVS, E-28049 Madrid, Spain.
    Performance of Fingerprint Quality Measures Depending on Sensor Technology2008Ingår i: Journal of Electronic Imaging (JEI), ISSN 1017-9909, E-ISSN 1560-229X, Vol. 17, nr 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although many image quality measures have been proposed for fingerprints, few works have taken into account how differences among capture devices impact the image quality. Several representative measures for assessing the quality of fingerprint images are compared using an optical and a capacitive sensor. We implement and test a representative set of measures that rely on different fingerprint image features for quality assessment. The capability to discriminate between images of different quality and the relationship with the verification performance are studied. For our verification experiments, we use minutiae- and ridge-based matchers, which are the most common approaches for fingerprint recognition. We report differences depending on the sensor, and interesting relationships between sensor technology and features used for quality assessment are also pointed out. © 2008 SPIE and IS&T.

  • 71.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Tome-Gonzalez, P.
    Universidad Autonoma de Madrid, Spain.
    Ruiz-Albacete, V.
    Universidad Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Autonoma de Madrid, Spain.
    Iris Recognition Based on SIFT Features2009Ingår i: 2009 First IEEE International Conference on Biometrics, Identity and Securit, 2009, s. 1-8Konferensbidrag (Refereegranskat)
    Abstract [en]

    Biometric methods based on iris images are believed to allow very high accuracy, and there has been an explosion of interest in iris biometrics in recent years. In this paper, we use the Scale Invariant Feature Transformation (SIFT) for recognition using iris images. Contrarily to traditional iris recognition systems, the SIFT approach does not rely on the transformation of the iris pattern to polar coordinates or on highly accurate segmentation, allowing less constrained image acquisition conditions. We extract characteristic SIFT feature points in scale space and perform matching based on the texture information around the feature points using the SIFT operator. Experiments are done using the BioSec multimodal database, which includes 3,200 iris images from 200 individuals acquired in two different sessions. We contribute with the analysis of the influence of different SIFT parameters on the recognition performance. We also show the complementarity between the SIFT approach and a popular matching approach based on transformation to polar coordinates and Log-Gabor wavelets. The combination of the two approaches achieves significantly better performance than either of the individual schemes, with a performance improvement of 24% in the Equal Error Rate.

  • 72.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Veldhuis, R. N. J.
    University of Twente, The Netherlands.
    Bazen, A. M.
    University of Twente, The Netherlands.
    Fierrez-Aguilar, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    On the relation between biometric quality and user-dependent score distributions in fingerprint verification2006Konferensbidrag (Refereegranskat)
  • 73.
    Alonso-Fernandez, Fernando
    et al.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Veldhuis, R. N. J.
    University of Twente, The Netherlands.
    Bazen, A. M.
    University of Twente, The Netherlands.
    Fierrez-Aguilar, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Ortega-Garcia, J.
    Escuela Politecnica Superior, Univ. Autonoma de Madrid, Spain.
    Sensor Interoperability and Fusion in Fingerprint Verification: A Case Study Using Minutiae- and Ridge-based Matchers2006Ingår i: 2006 9th International Conference on Control, Automation, Robotics and Vision, Vols 1- 5, Piscataway, N.J.: IEEE Press, 2006, s. 422-427Konferensbidrag (Refereegranskat)
    Abstract [en]

    Information fusion in fingerprint recognition has been studied in several papers. However, only a few papers have been focused on sensor interoperability and sensor fusion. In this paper, these two topics are studied using a multisensor database acquired with three different fingerprint sensors. Authentication experiments using minutiae and ridge-based matchers are reported. Results show that the performance drops dramatically when matching images from different sensors. We have also observed that fusing scores from different sensors results in better performance than fusing different instances from the same sensor. © 2006 IEEE.

  • 74.
    ALRimawi, Mohammed
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Doppler Wheel for Emulation of Automotive Radar Target2019Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Automotive radar is an emerging field of research and development. Technological ‎advancements in this field will improve safety for vehicles, pedestrians, and ‎bicyclists, and enable the development of autonomous vehicles. Usage of the ‎Automotive radar is expanding ‎in car and road areas to reduce collisions and ‎accident. Automotive radar ‎developers face a problem to test their radar sensor in ‎the street since there are a lot of interferences ‎signals, noise and unpredicted ‎situations. This thesis provides a part of the solution for this problem by designing a ‎device can demonstrate a different speeds value. This device will help the developer ‎to test their radar sensor inside an anechoic chamber room that provides accurate ‎control of the environmental conditions. This report shows how to ‎build the ‎measuring setup device, step by step to demonstrate the people and vehicle’s speed ‎‎in the street by a Doppler emulator using the wheel for millimetre FWMC radar. ‎Linear speed system needs a large space for testing, but using the rotational wheel ‎allow the developer to test the radar sensor in a small area. It begins with the wheel ‎design specifications and the relation between the ‎rotational speed (RPM) of the ‎wheel and the Doppler frequency. The Doppler ‎frequency is changed by varying the ‎speed of the wheel. Control and power circuit ‎was carefully designed to control the ‎wheel speed accurately. All the measuring ‎setup device parts were assembled in one ‎box. Also, signal processing was done by ‎MATLAB to measure the Doppler frequency ‎using millimetre FMCW radar sensor. ‎The measuring setup device was tested in the ‎anechoic chamber room for different speeds. the ‎manual and automatic tests show ‎good results to measure the different wheel speeds ‎with high accuracy.‎

  • 75.
    Alvarado, Cristian
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Ibrahim, Ayad
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Fjärrstyrning av videokamera2012Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    On some occasions it may be inappropriate with a cameraman behind the camera. In somecases there is no cameraman available or it is a smaller event, like a family celebration, to befilmed. It can also be difficult for a cameraman to shoot from certain angles. One solution forthis kind of situations can be to remotely control the camera movements. There are thosekinds of solutions on the market today but they either address professional filmmakers or thefunctionality is limited, for example by the absence of wireless remote control.This project aims to develop a solution to the problem with absence of wireless remote controland also a solution with more flexibility and less complexity than today’s solutions. The maindifference between this and existing solutions is the use of Bluetooth technology ascommunication between the devices. The project resulted in a solution consisting of twounits; one operating unit where the camera is mounted and a remote unit for control of theoperating unit. The remote unit is managed by the filmmaker. The remote unit consist of anAndroid application on a smart and which communicates with the control unit via Bluetooth.

  • 76.
    Alveflo, Victor
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Virtual Training Tool: Mjukvarubaserat utbildningsverktyg2014Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    En viktig del hos företag som tillverkar diverse industrimaskiner är att utbilda den personal som förväntas använda och underhålla maskinerna. Detta är för att ge användaren en god förståelse för hur maskinen i fråga fungerar och är uppbyggd. Vid sådana utbildningar är det viktigt att tillhandahålla användarvänligt utbildnings-material.

    Målet med detta examensarbete är att förbättra användarvänligheten för utbildningsmaterialet hos en viss utbildning för projektets uppdragsgivare. Den utbildning som skall förbättras går i dagsläget ut på att manuellt simulera processer hos en specifik maskin via en hårdvarubaserad simuleringsmiljö.

    Resultatet blev en lösning i form av en mjukvarubaserad simulator med tillhörande grafiskt användargränssnitt. Användaren kan därigenom på ett säkert sätt simulera maskinens beteende genom ett PC-program och då t.ex. skapa nödsituationer utan att användarens säkerhet sätts i fara.

  • 77.
    Amadeo, Marica
    et al.
    Dipartimento DIIES, Università Mediterranea di Reggio Calabria, Reggio Calabria, Italy.
    Campolo, Claudia
    Dipartimento DIIES, Università Mediterranea di Reggio Calabria, Reggio Calabria, Italy.
    Molinaro, Antonella
    Dipartimento DIIES, Università Mediterranea di Reggio Calabria, Reggio Calabria, Italy & Laboratoire des Signaux et Systémes (L2S), CentraleSupélec-CNRS-Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
    Harri, Jerome
    Department of Communication Systems, EURECOM, Sophia Antipolis, France.
    Rothenberg, Christian Esteve
    School of Electrical and Computer Engineering, University of Campinas (UNICAMP), Campinas, Brazil.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Enhancing the 3GPP V2X Architecture with Information-Centric Networking2019Ingår i: Future Internet, ISSN 1999-5903, E-ISSN 1999-5903, Vol. 11, nr 9, artikel-id 199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Vehicle-to-everything (V2X) communications allow a vehicle to interact with other vehicles and with communication parties in its vicinity (e.g., road-side units, pedestrian users, etc.) with the primary goal of making the driving and traveling experience safer, smarter and more comfortable. A wide set of V2X-tailored specifications have been identified by the Third Generation Partnership Project (3GPP) with focus on the design of architecture enhancements and a flexible air interface to ensure ultra-low latency, highly reliable and high-throughput connectivity as the ultimate aim. This paper discusses the potential of leveraging Information-Centric Networking (ICN) principles in the 3GPP architecture for V2X communications. We consider Named Data Networking (NDN) as reference ICN architecture and elaborate on the specific design aspects, required changes and enhancements in the 3GPP V2X architecture to enable NDN-based data exchange as an alternative/complementary solution to traditional IP networking, which barely matches the dynamics of vehicular environments. Results are provided to showcase the performance improvements of the NDN-based proposal in disseminating content requests over the cellular network against a traditional networking solution. © 2019 by the authors.

  • 78.
    AMEEN HASHIM, FARHAN
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Al Eid, Jamal
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Al-Salem, Abdulkhaliq
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Comparing of Real-Time Properties in Networks Based On IPv6 and IPv42013Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Real time applications over IP network became widely used in different fields; social video conference, online educational lectures, industrial, military, and online robotic medical surgery.

    Online medical surgery over IP network has experienced rapid growth in the last few years primarily due to advances in technology (e.g., increased bandwidth; new cameras, monitors, and coder/decoders (CODECs)) and changes in the medical care environment (e.g., increased outpatient care, remote surgeries).

    The purpose of this study was to examine and analyze the impact of IP networks parameters; delay, jitter, throughput, and drop packet on the performance of real-time medical surgery videos sent across different IP networks; native IPv6, native IPv4, 6to4 and 6in4 tunneling transition mechanisms and compare the behavior of video packets over IP networks. The impact of each parameter over IP networks is examined by using different video codecs MPEG-1, MPEG-2, and MPEG-4.

    This study has been carried out with two main parts; theoretical and practical part, the theoretical part of this study focused on the calculations of various delays in IP networks such as transmission, processing, propagation, and queuing delays for video packet, while the practical part includes; examining of video codecs throughput over IP networks by using jperf tool and examining delay, jitter, and packet drops for different packet sizes by using IDT-G tool and how these parameters can affect quality of received video.

    The obtained theoretical and practical results were presented in different tables and plotted into different graphs to show the performance of real time video over IP networks. These results confirmed that video codecs MPEG-1, MPEG-2, and MPEG-4 were highly impacted by encapsulation and de-capsulation process except MPEG-4 codec, MPEG-4 was the least impacted by IPv4, IPv6, and IP transition mechanisms concerning throughput and wastage bandwidth. It also indicated that using IPv6-to-4 and IPv6-in-4 tunneling mechanisms caused more bandwidth wastage, high delay, jitter, and packet drop than IPv4 and IPv6.

  • 79.
    Amin, Mohammed Nurul
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi. amin _ m 154@yahoo.com.
    Alam, Md. Obaidul
    Högskolan i Halmstad, Akademin för informationsteknologi. obai_ aust@yahoo.com.
    Landin, Lars
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Electrical and optical characteristics of Infrared Photodetectors based on InP nanowire2011Ingår i: 14th International Conference on Computer and Information Technology, ICCIT 2011, s. 629-634, artikel-id 6164864Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High speed photodetectors are most sophisticated optoelectronic devices, because it has high photo sensitivity, and allow a large wavelength range of detection as a receiver from 750 nm to 1.3-1.55 μm in the optical communication system. Since the last decade, the electrical and optical characteristics of photodetectors have been investigated to improve their performance and price. We have worked on two different type of infrared photodetectors based on nanowire. One photodetector was p-n photodiode, and the other one was p-i-n structure. We investigated the detector performance at 77K-300K temperature corresponding with wavelength in darkness and under illumination as regarding breakdown voltage, sensitivity, and quantum efficiency. We have also compared the differences between the two photodetectors performance characteristics. © 2011 IEEE.

  • 80.
    Amin, Muhammed Nurul
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi. amin_m154@yahoo.com.
    Alam, Md. Obaidul
    Högskolan i Halmstad, Akademin för informationsteknologi. obai_aust@yahoo.com.
    Electro-optical characterisation of inp nanowire based p-n, p-i-n infrared photodetectors2012Ingår i: Journal of Communications, ISSN 1796-2021, E-ISSN 1796-2021, Vol. 7, nr 11, s. 808-820Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High speed photodetectors are most sophisticated optoelectronic devices, because it has high photo sensitivity, low noise, high conversion efficiency and allow a large wavelength range of detection from 750 nm to 1.3-1.55 pm in the optical communication system. These photodetector is used as an optical receiver which transforms the energy of optical radiation such as infrared, visible or ultraviolet into the electrical signal that is convenient for measurement. Since the last decade, the electro-optical characterisation of photodetectors has been investigated to improve their performance and price. In this paper, we are going to discuss the characterisation of the two different type infrared photodectors based on nanowire that we have worked on our project. One photodetector is p- n nanowire structure, and another is p-i-n structure. Both photodetectors is worked based on internal photoelectric effect and on the theory of p-n junction. We investigated the detector performance at 77K-300K temperature corresponding with wavelength in darkness and under illumination as regarding breakdown voltage, sensitivity, and quantum efficiency. We have also compared the differences between the two photodetectors performance characteristics. © 2012 ACADEMY PUBLISHER.

  • 81.
    Andersen, Niklas
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Energiteknik.
    Ismail, Zahir
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Energiteknik.
    Solel från ljudbarriär: längs Annetorpsvägen i Hyllie, Malmö2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    City of Malmö has ambitions for the district Hyllie to become a demonstrative area ofsustainable urban development. As a part of this the following report aims to investigate the potential in using noise barriers combined with photovoltaics along Annetorpsvägen to generate solar electricity. To quantify the losses that shadows from buildings along the roadmight cause, a 3D-model of the area was constructed in SketchUp. This digital model made it possible to simulate shadows and how they change over the year. A reference model of a photovoltaic noise barrier (PVNB) was constructed and used to find the dates on which the solar cells are shadowed depending on building heights and positioning of the barrier.

    The results show that two lengths with a total distance of 400 meters is appropriate for applying photovoltaic noise barriers. Along distance A, a PVNB with a total capacity of 19 kWp is expected to generate 18 000 kWh per year assuming realistic shadowing, which equals 6% losses compared to production without shadows. The PVNB along distance B with installed capacity of 37 kWp has no considerable problems with shadowing and is expected to generate 37 500 kWh per year. This gives a total production of 56 500 kWh per year.

    The combined investment costs (excluding costs for the actual noise barrier) for both power plants are assumed to be approximately one million SEK. Expected economical outcome is a negative capital value after 25 years, although a change of critical factors such as investment aid, investment cost, electricity prices and cost of capital may result in a more positive outcome. Production losses from shadowing and dirt seem to have a minimal effect on the outcome

    Despite uncertainty in the economical outcome, realizing the project would have several other positive effects such as reduction of carbon dioxide emissions and a positive impact on the public view of renewable energy.

  • 82.
    Anderson, S. J.
    et al.
    MIT.
    Karumanchi, S. B.
    MIT.
    Iagnemma, Karl
    MIT.
    Constraint-based planning and control for safe, semi-autonomous operation of vehicles2012Ingår i: 2012 IEEE intelligent vehicles symposium: (IV 2012) : Alcala de Henares, Madrid, Spain, 3-7 June 2012, 2012, s. 383-388Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a new approach to semi-autonomous vehicle hazard avoidance and stability control, based on the design and selective enforcement of constraints. This differs from traditional approaches that rely on the planning and tracking of paths. This emphasis on constraints facilitates "minimally-invasive" control for human-machine systems; instead of forcing a human operator to follow an automation-determined path, the constraint-based approach identifies safe homotopies, and allows the operator to navigate freely within them, introducing control action only as necessary to ensure that the vehicle does not violate safety constraints. The method evaluates candidate homotopies based on "restrictiveness", rather than traditional measures of path goodness, and designs and enforces requisite constraints on the human's control commands to ensure that the vehicle never leaves the controllable subset of a desired homotopy. Identification of these homotopic classes in off-road environments is performed using geometric constructs. The goodness of competing homotopies and their associated constraints is then characterized using geometric heuristics. Finally, input limits satisfying homotopy and vehicle dynamic constraints are enforced using threat-based feedback mechanisms to ensure that the vehicle avoids collisions and instability while preserving the human operator's situational awareness and mental models. The methods developed in this work are shown in simulation and experimentally demonstrated in safe, high-speed teleoperation of an unmanned ground vehicle. © 2012 IEEE.

  • 83.
    Anderson, S.
    et al.
    MIT.
    Peters, S.
    MIT.
    Iagnemma, Karl
    MIT.
    Overholt, J.
    US Army Tank Automotive RDE Center (TARDEC).
    Semi-Autonomous Stability Control and Hazard Avoidance for Manned and Unmanned Ground Vehicles2010Ingår i: Proceedings of the 27th Army Science Conference, 2010, s. 1-8Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for trajectory planning, threatassessment, and semi-autonomous control of manned andunmanned ground vehicles. A model predictive controlleriteratively replans a stability-optimal trajectory through the saferegion of the environment while a threat assessor and semi-autonomous control law modulate driver and controller inputs tomaintain stability, preserve controllability, and ensure that thevehicle avoids obstacles and hazardous areas. The efficacy of thisapproach in avoiding hazards while accounting for various typesof human error, including errors caused by time delays, isdemonstrated in simulation.

  • 84.
    Anderson, S.
    et al.
    MIT.
    Peters, S.
    MIT, USA.
    Pilutti, T.
    Ford Research Laboratories, Ford Motor Co., Dearborn, MI 48124, United States.
    Tseng, E.
    Ford Research Laboratories, Ford Motor Co., Dearborn, MI 48124, United States.
    Iagnemma, Karl
    MIT.
    Semi-autonomous Avoidance of Moving Hazards for Passenger Vehicles2010Ingår i: Proceedings of the ASME Dynamic Systems and Control Conference--2010: presented at 2010 ASME Dynamic Systems and Control Conference, September 12-15, 2010 Cambridge, Mass., USA, New York: ASME Press, 2010, s. 141-148Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for semi-autonomous hazard avoidance in the presence of unknown moving obstacles and unpredictable driver inputs. This method iteratively predicts the motion and anticipated intersection of the host vehicle with both static and dynamic hazards and excludes projected collision states from a traversable corridor. A model predictive controller iteratively replans a stability-optimal trajectory through the navigable region of the environment while a threat assessor and semi-autonomous control law modulate driver and controller inputs to maintain stability, preserve controllability, and ensure safe hazard avoidance. The efficacy of this approach is demonstrated through both simulated and experimental results using a semi-autonomously controlled Jaguar S-Type. Copyright © 2010 by ASME.

  • 85.
    Anderson, Sterling J.
    et al.
    Department of Mechanical Engineering Massachusetts Institute of Technology, Cambridge, MA, USA.
    Karumanchi, Sisir B.
    Department of Mechanical Engineering Massachusetts Institute of Technology, Cambridge, MA, USA.
    Iagnemma, Karl
    Department of Mechanical Engineering Massachusetts Institute of Technology, Cambridge, MA, USA.
    Walker, James M.
    Quantum Signal, LLC, Saline, MI, USA.
    The intelligent copilot: A constraint-based approach to shared-adaptive control of ground vehicles2013Ingår i: IEEE Intelligent Transportation Systems Magazine, ISSN 1939-1390, Vol. 5, nr 2, s. 45-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work presents a new approach to semi-autonomous vehicle hazard avoidance and stability control, based on the design and selective enforcement of constraints. This differs from traditional approaches that rely on the planning and tracking of paths and facilitates minimally-invasive control for human-machine systems. Instead of forcing a human operator to follow an automation-determined path, the constraint-based approach identifies safe homotopies, and allows the operator to navigate freely within them, introducing control action only as necessary to ensure that the vehicle does not violate safety constraints. This method evaluates candidate homotopies based on restrictiveness rather than traditional measures of path goodness, and designs and enforces requisite constraints on the human's control commands to ensure that the vehicle never leaves the controllable subset of a desired homotopy. This paper demonstrates the approach in simulation and characterizes its effect on human teleoperation of unmanned ground vehicles via a 20-user, 600-trial study on an outdoor obstacle course. Aggregated across all drivers and experiments, the constraintbased control system required an average of 43% of the available control authority to reduce collision frequency by 78% relative to traditional teleoperation, increase average speed by 26%, and moderate operator steering commands by 34%. © 2009-2012 IEEE

  • 86.
    Anderson, Sterling J.
    et al.
    MIT.
    Karumanchi, Sisir B.
    MIT.
    Johnson, Bryan
    Quantum Signal LLC..
    Perlin, Victor
    Quantum Signal LLC..
    Rohde, Mitchell
    Quantum Signal LLC..
    Iagnemma, Karl
    MIT.
    Constraint-based semi-autonomy for unmanned ground vehicles using local sensing2012Ingår i: UNMANNED SYSTEMS TECHNOLOGY XIV, Bellingham, WA: SPIE - International Society for Optical Engineering, 2012, s. Article no. 83870K-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Teleoperated vehicles are playing an increasingly important role in a variety of military functions. While advantageous in many respects over their manned counterparts, these vehicles also pose unique challenges when it comes to safely avoiding obstacles. Not only must operators cope with difficulties inherent to the manned driving task, but they must also perform many of the same functions with a restricted field of view, limited depth perception, potentially disorienting camera viewpoints, and significant time delays. In this work, a constraint-based method for enhancing operator performance by seamlessly coordinating human and controller commands is presented. This method uses onboard LIDAR sensing to identify environmental hazards, designs a collision-free path homotopy traversing that environment, and coordinates the control commands of a driver and an onboard controller to ensure that the vehicle trajectory remains within a safe homotopy. This system's performance is demonstrated via off-road teleoperation of a Kawasaki Mule in an open field among obstacles. In these tests, the system safely avoids collisions and maintains vehicle stability even in the presence of "routine" operator error, loss of operator attention, and complete loss of communications.

  • 87.
    Anderson, Sterling J.
    et al.
    Massachusetts Institute of Technology.
    Peters, Steven C.
    Massachusetts Institute of Technology.
    Iagnemma, Karl
    Massachusetts Institute of Technology.
    Pilutti, Tom E.
    Ford Research Laboratories, Ford Motor Company, Dearborn, MI, United States.
    A Unified Approach to Semi-Autonomous Control of Passenger Vehicles in Hazard Avoidance Scenarios2009Ingår i: IEEE 2009 IEEE International Conference on Systems, Man and Cybernetics, SMC 2009, VOLS 1-9, Piscataway, N.J.: IEEE Press, 2009, s. 2032-2037Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the design of unified active safety framework that combines trajectory planning, threat assessment, and semi-autonomous control of passenger vehicles into a single constrained-optimal-control-based system. This framework allows for multiple actuation modes, diverse trajectory-planning objectives, and varying levels of autonomy. The vehicle navigation problem is formulated as a constrained optimal control problem with constraints bounding a navigable region of the road surface. A model predictive controller iteratively plans the best-case vehicle trajectory through this constrained corridor. The framework then uses this trajectory to assess the threat posed to the vehicle and intervenes in proportion to this threat. This approach minimizes controller intervention while ensuring that the vehicle does not depart from a navigable corridor of travel. Simulated results are presented here to demonstrate the framework's ability to incorporate multiple threat thresholds and configurable intervention laws while sharing control with a human driver. ©2009 IEEE.

  • 88.
    Anderson, Sterling J.
    et al.
    MIT.
    Peters, Steven C.
    MIT.
    Pilutti, Tom E.
    Ford Research Laboratories, Dearborn, MI 48124, United States.
    Iagnemma, Karl
    MIT.
    Design and Development of an Optimal-Control-Based Framework for Trajectory Planning, Threat Assessment, and Semi-autonomous Control of Passenger Vehicles in Hazard Avoidance Scenarios2011Ingår i: Robotics Research, Berlin: Springer Berlin/Heidelberg, 2011, s. 39-54Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the design of an optimal-control-based active safety framework that performs trajectory planning, threat assessment, and semi-autonomous control of passenger vehicles in hazard avoidance scenarios. This framework allows for multiple actuation modes, diverse trajectory-planning objectives, and varying levels of autonomy. A model predictive controller iteratively plans a best-case vehicle trajectory through a navigable corridor as a constrained optimal control problem. The framework then uses this trajectory to assess the threat posed to the vehicle and intervenes in proportion to this threat. This approach minimizes controller intervention while ensuring that the vehicle does not depart from a navigable corridor of travel. Simulation and experimental results are presented here to demonstrate the framework's ability to incorporate configurable intervention laws while sharing control with a human driver. © 2011 Springer-Verlag.

  • 89.
    Anderson, Sterling J.
    et al.
    MIT.
    Peters, Steven C.
    MIT.
    Pilutti, Tom E.
    Ford Research Laboratories, Ford Motor Company, Dearborn, MI, United States.
    Iagnemma, Karl
    MIT.
    Experimental Study of an Optimal-Control-Based Framework for Trajectory Planning, Threat Assessment, and Semi-Autonomous Control of Passenger Vehicles in Hazard Avoidance Scenarios2010Ingår i: FIELD AND SERVICE ROBOTICS, Berlin: Springer Berlin/Heidelberg, 2010, s. 59-68Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the design of an optimal-control-based active safety framework that performs trajectory planning, threat assessment, and semi-autonomous control of passenger vehicles in hazard avoidance scenarios. The vehicle navigation problem is formulated as a constrained optimal control problem with constraints bounding a navigable region of the road surface. A model predictive controller iteratively plans an optimal vehicle trajectory through the constrained corridor. Metrics from this "best-case" scenario establish the minimum threat posed to the vehicle given its current state. Based on this threat assessment, the level of controller intervention required to prevent departure from the navigable corridor is calculated and driver/controller inputs are scaled accordingly. This approach minimizes controller intervention while ensuring that the vehicle does not depart from a navigable corridor of travel. It also allows for multiple actuation modes, diverse trajectory-planning objectives, and varying levels of autonomy. Experimental results are presented here to demonstrate the framework's semi-autonomous performance in hazard avoidance scenarios.

  • 90. Andersson, Emil
    et al.
    Schedin, Niklas
    Räkning av Personer i Rörelse med Bildtolkning2016Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I dagens samhälle är företag beroende av markadsundersökningar för att forsatt kunna växa. En undersökning kan vara att se personflödet i varuhus. Det här projektet riktar sig till att skapa en bildtolkningsalgoritm som klarar av att räkna antalet personer som passerar förbi en kamera. Systemet består av två stycken räknare, en för de personer som går in och en för de som går ut. För att lösa denna uppgift så har projektet delats in i två faser, en utbildningsfas och en utvecklingsfas. Utbildningsfasen är till för att få kunskap om bildtolkning, eftersom projektmedlemarna inte har någon tidigare erfarenhet om det området. Utvecklingsfasen är då den slutliga algoritmen utvecklas utifrån de kunskaper som utbildningsfasen har givit. Det slutliga resultatet visar att vid låg belastning är algoritmen pålitlig, men när den belastas med allt fler personer börjar räknarna avvika ifrån de faktiska värdena.

  • 91. Andersson, Emma
    et al.
    Bröhne, Johan
    High Quality of Service in SDN: Bandwidth gurantee with QoS2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Video streaming through IP networks has risen rapidly over the recent years, and will continue to do so over the coming years. In addition to this, new technologies such as Virtual Reality and robotics will lead to many new applications that will put high pressure on the networks. To combat these challenges, networks need to be application sensitive, and be able to provide Quality of Service (QoS) based on requirement. Network paradigms like Software Defined Networking (SDN) enables the network to be directly programmable, and could thus solve the challenge. In this thesis, the objective is to research if SDN can provide High QoS.

    Methods are developed to achieve High QoS with SDN. A combination of Differentiated Services Code Point (DSCP) values and DSCP remarking with Meters are used enable High QoS and together they can give bandwidth guarantee. As a result of the thesis, a solid theoretical method is provided for achieving QoS, tests are performed and show that QoS can be implemented in SDN, but it is unable to implement High QoS due to the lack of implementation for Meters with DSCP remarking.

  • 92.
    Andersson, Gustav
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Energiteknik.
    Ericsson, Emil
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Energiteknik.
    Dark Ages Interferometer (DALI) Deployment Rover: Energy System2014Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I kosmologi kallas epoken mellan “rekombinationen till väte” och bildandet av de första stjärnorna för “den mörka tidsåldern”. Från denna tid finns endast spår i form av strålning från neutralt väte. Denna strålning kan enligt astronomer vara en viktigare källa till data om universums uppkomst än den kosmiska mikrovågsstrålningen. Därför arbetar NASA/JPL med att hitta metoder att observera denna rika källa till data. Den mest använda metoden är att använda lågfrekventa radioteleskop för att observera strålning med våglängder mellan 3-30 m och frekvenser mellan 10-100 Mhz. Ett stort problem med så kort strålning är den lätt störs ut av mänsklig påverkan och andra radiokällor, tillexempel solen. Ett sätt att undvika antropogen störning är att bygga ett radioteleskop på månens baksida. Eftersom månen är i en låst bana runt jorden vänder den alltid samma sida bort från planeten. Därför är platsen alltid i radioskugga från jorden ochstörs inte av mänsklighetens radiotrafik. JPL har lång erfarenhet av användandet av robotfarkoster för att utforska himlakroppar. År 2030 vill de sända en så kallad rover för att upprätta en grupp radioteleskop på månen med syftet att införskaffa data om “den mörka tidsåldern.” Högskolan i Halmstad erbjuder sedan 2013 studenter möjligheten att skriva sitt examensarbete i samarbete med NASA/JPL om konstruktionen av denna rover. Detta arbete har ämnat finna en lösning på rovens energiförsörjning genom att använda solceller och batterier. Slutsatsen har varit att det är möjligt att driva en rover på månen med solceller samt batterier. Ett krav är att rovern värms med radioisotoperunder natten för att minska energianvändningen.

  • 93.
    Andersson, Johan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Kleihs, Marcus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Routing Interior2013Studentarbete andra termin, 5 poäng / 7,5 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    När datatrafik färdas genom ett nätverk så passerar det routrar och switcharsamtidigt som dessa enheter visar åt vilket håll paketet ska skickas. Detta kallas förrouting. För att paketen ska hitta rätt väg så använder man sig av routingprotokoll,som vägleder trafiken dit de ska, och olika protokoll har olika fördelar samtidigtsom de används vid olika tillfällen. Målet var att skapa ett stort enhetligt nätverksom tål höga belastningar, har en hög uppkopplingsprocent samtidigt som det skavara lätt att expandera i framtiden. Det största problemet var hur trafiken färdasmellan varje kontor, men problem som hur användarna ska vara uppkopplade tillInternet tas upp i rapporten. Nätverket använder sig av OSPF som routingprotokoll.Varje kontor delas in i områden, totallystubby area, vilket kortar nedroutingtabellen i Stockholm. Resultatet blir att snabba beslut tas när paket skaskickas inom ett kontor och när det ska utanför ett kontor så används en defaultroute. Samtidigt som kontoren är lätta att bygga ut då totallystubby area har endefault route till Stockholm.

  • 94.
    Andersson, Robin
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET).
    Electric power quality in low voltage grid: Office buildings and rural substation2015Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The modern society uses more and more electronic devices needed to being able to function together. This put higher demands on the electrical grid together with that the typical load have changed from the past. Therefore utility companies are obliged to keep the voltage within certain limits for this to function. What exact these limits have been have not always been clear since they have not been gathered in one single document. 

    This thesis is a cooperation with Kraftringen who also has been the initiator. Kraftringen would like to become more proactive in their work regarding electric power quality. For becoming more proactive continuously measurements have to be done but the locations have to be carefully selected in the beginning to get a wider perspective of the grid.

    Energy markets inspectorate (EI) is supervisory of the electric power quality in Sweden and since 2011 they have published a code of statutes (EIFS 2011:2 later 2013:1) intended to summarize limits on voltage. Some of the electrical power quality aspects are not mentioned in EIFS 2013:1 and standards have to be used to find limited values. Flicker and interharmonics are not mentioned in EIFS 2013:1 and for values on flicker the standard SS-EN 50160 has to be used and for interharmonics the standard SS-EN 61000-2-2 state limit values. Besides all this there are standards with stricter limits than EIFS 2013:1 e.g. for total harmonic distortion on voltage were SS-EN 61000-2-2 suggest 6 % instead of 8 %.

    Three different field studies have been conducted in order to get some perception of the present situation regarding electric power quality. Two measurements were conducted on a typical office building because they represents a large part of the typical load in Lund. The third measurement was conducted on a substation in a rural area to get a perception of the situation outside urban areas. 

    These measurements shown that the overall electric power quality was within given limits according to EIFS 2013:1 and different standards. However, conducted measurements shown some interesting results. Both the typical office buildings have a slightly capacitive power factor which results in that the voltage inside the building is going to be slightly higher than at the substation. Since the voltage level at the measured urban substation was above nominal voltage level with about 2-5 % this could be problematic. Another eventual problem with a load with a capacitive power factor is resonance with the inductive parts of the grid like transformers leading to magnified harmonic levels.

    It is suggested that Kraftringen expand their number of permanent electric power quality measurement locations to get a better overview of the present situation. The best suited locations to start with are such that have received complaints earlier, preferably measured on the low voltage side of the transformer for also register the amount of zero sequence harmonics. Next step in the measurement expansion would be substations known to be under higher load than others or substations with a PEN-conductor in a smaller area than the phase conductors, supplying a typical office load with high amounts of third harmonics and unbalance. From this it would be appropriate to spread out the measurement locations geographically to better get to know the grids behaviour. 

  • 95.
    Andersson, Roland
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Utvinning av data ur mobiltelefoner: En valideringsstudie av forensiska verktyg2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den vetenskapliga aspekten i de flesta forensiska discipliner är välgrundad och prövad under ett långt tidsperspektiv. Det ökande användandet av digital teknik har gjort att en ny forensisk disciplin har vuxit fram och den vetenskapliga grunden i detta nya forensiska område är i många avseenden fortfarande outforskat. Inom det svenskarättsväsendet krävs att de forensiska metoder som används inom en brottsutredning ska vara kvalitetssäkrade och i största mån vara ackrediterade av ettackrediteringsorgan. Det finns idag få relevanta studier kring validering av forensiska metoder som hanterar småskaliga enheter som smarta mobiler.

    I denna rapport analyseras de metoder som används för att utvinna data från mobiltelefon och hur dessa metoder kan anses vara forensiskt korrekta. Rapporten presenterar ett nytt ramverk för att validera de metoder som används av ett forensisk verktyg. Ramverket är kvalitetssäkrat genom att utgå ifrån tidigare vetenskaplig studier och är praktiskt testad i laboratoriemiljö. Ramverket ska kunna användas direkt inom en forensisk verksamhet som kräver validering.

  • 96.
    Andreasson, Henrik
    et al.
    Örebro University, Örebro, Sweden.
    Bouguerra, Abdelbaki
    Örebro University, Örebro, Sweden.
    Åstrand, Björn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Gold-fish SLAM: An application of SLAM to localize AGVs2014Ingår i: Field and Service Robotics: Results of the 8th International Conference / [ed] Kazuya Yoshida & Satoshi Tadokoro, Heidelberg: Springer, 2014, s. 585-598Konferensbidrag (Refereegranskat)
    Abstract [en]

    The main focus of this paper is to present a case study of a SLAM solution for Automated Guided Vehicles (AGVs) operating in real-world industrial environments. The studied solution, called Gold-fish SLAM, was implemented to provide localization estimates in dynamic industrial environments, where there are static landmarks that are only rarely perceived by the AGVs. The main idea of Gold-fish SLAM is to consider the goods that enter and leave the environment as temporary landmarks that can be used in combination with the rarely seen static landmarks to compute online estimates of AGV poses. The solution is tested and verified in a factory of paper using an eight ton diesel-truck retrofitted with an AGV control system running at speeds up to 3m/s. The paper includes also a general discussion on how SLAM can be used in industrial applications with AGVs. © Springer-Verlag Berlin Heidelberg 2014.

  • 97.
    Andreev, Sergey D.
    et al.
    Saint-Petersburg State University of Aerospace Instrumentation, Saint-Petersburg, Russia.
    Turlikov, Andrey M.
    Saint-Petersburg State University of Aerospace Instrumentation, Saint-Petersburg, Russia.
    Vinel, Alexey
    Saint-Petersburg State University of Aerospace Instrumentation, Saint-Petersburg, Russia.
    Performance analysis of a high-speed ultra-wideband WPAN MAC2007Ingår i: Proceedings of the 14th International Conference on Analytical and Stochastic Modelling Techniques and Applications: 4 - 6 June 2007, Prague, Czech Republic ; ASMTA 2007 / [ed] Khalid Al-Begain, Armin Heindl & Miklos Telek, Sbr.-Dudweiler: Digitaldruck Pirrot GmbH , 2007, s. 44-49Konferensbidrag (Refereegranskat)
    Abstract [en]

    The current paper addresses the problem of the throughput-delay performance of a contemporary WPAN MAC standard. A brief overview of the standard functionality is first presented that allows a system model derivation. Two different acknowledgement policies are described under which the channel operation is considered. Two possible input traffic models are also considered one of them being saturation conditions under which the performance analysis is done that is further verified by means of the simulation. The obtained results show the system behavior as the number of channel users increase and allow the tuning of the protocol parameters to improve the performance.

  • 98.
    Andreev, Sergey D.
    et al.
    Saint-Petersburg State University of Aerospace Instrumentation, Saint-Petersburg, Russia.
    Vinel, Alexey
    Saint-Petersburg State University of Aerospace Instrumentation, Saint-Petersburg, Russia.
    Performance analysis and enhancement of an ultra-wideband WPAN MAC in the presence of noise2007Ingår i: XI International Symposium on Problems of Redundancy in Information and Control Systems, Saint Petersburg, 2007, s. 117-122Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper addresses the performance evaluation of the contemporary UWB WPAN standard. The basic standard functionality is described for which a system model is derived that accounts for the possible errors due to the background noise. Two realistic scenarios of the saturation conditions and the Bernoulli packet arrivals are considered to calculate the system throughput and the mean initial packet delay. The redundancy-based error detection mechanism that is implemented in the standard is discussed that allows the enhancement of the system performance. The obtained results are compared against the simulation which shows a good accordance with the analytical results and a distinct superiority of the introduced enhancement.

  • 99.
    Andreev, Sergey
    et al.
    Department of Communications Engineering, Tampere University of Technology, Tampere, Finland.
    Galinina, Olga
    Speech Technology Center, St. Petersburg, Russia.
    Vinel, Alexey
    Saint-Petersburg Institute for Informatics and Automation, Russian Academy of Sciences, St. Petersburg, Russia.
    Cross-Layer Channel-Aware Approaches for Modern Wireless Networks2010Konferensbidrag (Refereegranskat)
  • 100.
    Andreev, Sergey
    et al.
    Department of Communications Engineering, Tampere University of Technology, Finland.
    Galinina, Olga
    Department of Communications Engineering, Tampere University, Finland of Technology.
    Vinel, Alexey
    Department of Communications Engineering, Tampere University, Finland of Technology.
    Performance Evaluation of a Three Node Client Relay System2011Ingår i: International Journal of Wireless Networks and Broadband Technologies, ISSN 2155-6261, Vol. 1, nr 1, s. 73-84Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the authors examine a client relay system comprising three wireless nodes. Closed-form expressions for mean packet delay, as well as for throughput, energy expenditure, and energy efficiency of the source nodes are also obtained. The precision of the established parameters is verified by means of simulation.

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