Obstacle Avoidance for a Game Theoretically Controlled Formation of Unmanned Vehicles

The thesis provides a game theoretical approach to the control of a formation of unmanned vehicles. The objectives of the formation are to follow a prescribed trajectory, avoiding obstacle(s) while maintaining the geometry of the formation. Formation control is implemented using game theory while obstacles are avoided using Null Space Based Behavioral Control algorithm. Different obstacle avoidance scenarios are analyzed and compared. Numerical simulation results are presented, to validate the proposed approach

Recent activities of IAG working group “Ionosphere Prediction”

Ionospheric disturbances pose, for instance, an increasing risk on economy, national security, satellite and airline operations, communications networks and the navigation systems. Constructing forecasted ionospheric products with a reliable accuracy is still an ongoing challenge. In this sense, a Working Group (WG) with the title “Ionosphere Prediction” within the International Association of Geodesy (IAG) under Sub-Commission 4.3 “Atmosphere Remote Sensing” of the Commission 4 “Positioning and Applications” has been created and is actively working since 2015 to encourage scientific collaborations on developing models and discussing challenges of the ionosphere prediction problem. Different centers contribute to the WG such as the German Aerospace Center (DLR), Universitat Politècnica de Catalunya (UPC), Technical University of Munich (TUM) and GMV. One of the main focus of the WG is to evaluate different ionosphere prediction approaches and products which are highly depending on solar and geomagnetic conditions as well as on data from different measurement techniques (e.g. GNSS) with varying spatial-temporal resolution, sensitivity and latency. In this contribution, the recent progress of the WG on ionosphere prediction studies including individual and cooperated activities will be presented.Postprint (published version

High-resolution ionosphere corrections for single-frequency positioning

The ionosphere is one of the main error sources in positioning and navigation; thus, information about the ionosphere is mandatory for precise modern Global Navigation Satellite System (GNSS) applications. The International GNSS Service (IGS) and its Ionosphere Associated Analysis Centers (IAAC) routinely provide ionospheric information in terms of global ionosphere maps (final GIM). Typically, these products are modeled using series expansion in terms of spherical harmonics (SHs) with a maximum degree of n=15 and are based on post processed observations from Global Navigation Satellite Systems (GNSS), as well as final satellite orbits. However, precise applications such as autonomous driving or precision agriculture require real-time (RT) information about the ionospheric electron content with high spectral and spatial resolution. Ionospheric RT-GIMs are disseminated via Ntrip protocol using the SSR VTEC message of the RTCM. This message can be streamed in RT, but it is limited for the dissemination of coefficients of SHs of lower degrees only. It allows the dissemination of SH coefficients up to a degree of n=16. This suits to most the SH models of the IAACs, but higher spectral degrees or models in terms of B-spline basis functions, voxels, splines and many more cannot be considered. In addition to the SHs, several alternative approaches, e.g., B-splines or Voxels, have proven to be appropriate basis functions for modeling the ionosphere with an enhanced resolution. Providing them using the SSR VTEC message requires a transfer to SHs. In this context, the following questions are discussed based on data of a B-spline model with high spectral resolution; (1) How can the B-spline model be transformed to SHs in order to fit to the RTCM requirements and (2) what is the loss of detail when the B-spline model is converted to SHs of degree of n=16? Furthermore, we discuss (3) what is the maximum necessary SH degree n to convert the given B-spline model and (4) how can the transformation be performed to make it applicable for real-time applications? For a final assessment, we perform both, the dSTEC analysis and a single-frequency positioning in kinematic mode, using the transformed GIMs for correcting the ionospheric delay. The assessment shows that the converted GIMs with degrees n=30 coincide with the original B-spline model and improve the positioning accuracy significantly.Peer ReviewedPostprint (published version

Near real-time estimation of ionosphere vertical total electron content from GNSS satellites using B-splines in a Kalman filter

Abstract. Although the number of terrestrial global navigation satellite system (GNSS) receivers supported by the International GNSS Service (IGS) is rapidly growing, the worldwide rather inhomogeneously distributed observation sites do not allow the generation of high-resolution global ionosphere products. Conversely, with the regionally enormous increase in highly precise GNSS data, the demands on (near) real-time ionosphere products, necessary in many applications such as navigation, are growing very fast. Consequently, many analysis centers accepted the responsibility of generating such products. In this regard, the primary objective of our work is to develop a near real-time processing framework for the estimation of the vertical total electron content (VTEC) of the ionosphere using proper models that are capable of a global representation adapted to the real data distribution. The global VTEC representation developed in this work is based on a series expansion in terms of compactly supported B-spline functions, which allow for an appropriate handling of the heterogeneous data distribution, including data gaps. The corresponding series coefficients and additional parameters such as differential code biases of the GNSS satellites and receivers constitute the set of unknown parameters. The Kalman filter (KF), as a popular recursive estimator, allows processing of the data immediately after acquisition and paves the way of sequential (near) real-time estimation of the unknown parameters. To exploit the advantages of the chosen data representation and the estimation procedure, the B-spline model is incorporated into the KF under the consideration of necessary constraints. Based on a preprocessing strategy, the developed approach utilizes hourly batches of GPS and GLONASS observations provided by the IGS data centers with a latency of 1 h in its current realization. Two methods for validation of the results are performed, namely the self consistency analysis and a comparison with Jason-2 altimetry data. The highly promising validation results allow the conclusion that under the investigated conditions our derived near real-time product is of the same accuracy level as the so-called final post-processed products provided by the IGS with a latency of several days or even weeks.Publisher's Versio

Utility of Somatostatin Receptors in Gastrointestinal Tract and Pancreas Neuroendocrine Tumors

Aim: Neuroendocrine tumors (NETs) are heterogenous group of tumors. Most of gastroenteropancreatic NETs (GEPNETs) are welldifferentiated low-grade tumors but a subset of them displays aggressive behavior. Somatostatin receptors (SSTR) play an im-portant role in the pathogenesis of GEPNETs, and they display targets for therapy. We aimed to evaluate SSTR2, SSTR3, SSTR5 by immunohistochemistry in GEPNETs and correlate with clinicopathological findings.Materials and Methods: Totally 61 cases were enrolled into this study and evaluated for SSTR2, 3, and 5 by im-munohistochemically.Results: Mostly the patients had low-grade neoplasms and 23% of them had metastatic disease. Total-ly, 73%, 47%, and 26% positivity were found by SSTR2, SSTR3, and SSTR5, respectively. The histopathological grade was increased relative to decreasing expression levels of SSTRs. Among metastatic neoplasms, SSTR2 positivity was found to be greater than a non-metastatic disease.Conclusion:In conclusion, SSTRs are useful to predict the clinical outcomes as well as target of therapy

Reporterskie zmagania z obrazami pamięci : wokół "podróży do Włoch" Jarosława Iwaszkiewicza

Jarosław Iwaszkiewicz's Italian travels are the record of the real journey to Apennine Peninsula in the form of reportages. The important fact is that each report constitutes a particular collection of impressions and observations of not the very journey as such but they constitute a compilation of author's encounters with the place he described. As a subject of description the author chose places less known because he wanted to depart from run-of-the-mill description of the Italian space. The form of a reportage allows Iwaszkiewicz to connect freely the description of urban spaces with reflections on history of art and observations on political and economic situation of Italy. Moreover, he allows certain textual polyphony, justifies subjectivity, selectivity of observation and justifies the lack of interest in the chronology of events or the cause and effect relationship of the plots taken. At the same time Italian travels are Iwaszkiewicz's reflections on his own life and work. The text devoted to Sicily (which is one out of seven reportages in the volume) is analysed in detail

St. Patrick’s Day 2015 geomagnetic storm analysis based on Real Time Ionosphere Monitoring

A detailed analysis is presented for the days in March, 2015 surrounding St. Patrick’s Day 2015 geomagnetic storm, based on the existing real-time and near real-time ionospheric models (global or regional) within the group, which are mainly based on Global Navigation Satellite Systems (GNSS) and ionosonde data. For this purpose, a variety of ionospheric parameters is considered, including Total Electron Content (TEC), F2 layer critical frequency (foF2), F2 layer peak (hmF2), bottomside halfthickness (B0) and ionospheric disturbance W-index. Also, ionospheric high-frequency perturbations such as Travelling Ionospheric Disturbances (TIDs), scintillations and the impact of solar flares facing the Earth will be presented to derive a clear picture of the ionospheric dynamicsPostprint (published version

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]