TY - JOUR AB - Non-trivial electronic properties of silver telluride and other chalcogenides, such as the presence of a topological insulator state, electronic topological transitions, metallization, and the possible emergence of superconductivity under pressure have attracted attention in recent years. In this work, we studied the electronic properties of silver selenide (Ag2Se). We performed direct current electrical resistivity measurements, in situ Raman spectroscopy, and synchrotron x-ray diffraction accompanied by ab initio calculations to explore pressure-induced changes to the atomic and electronic structure of Ag2Se. The temperature dependence of the electrical resistivity was measured up to 30 GPa in the 4–300 K temperature interval. Resistivity data showed an unusual increase in the thermal energy gap of phase I, which is a semiconductor under ambient conditions. Recently, a similar effect was reported for the 3D topological insulator Bi2Se3. Raman spectroscopy studies revealed lattice instability in phase I indicated by the softening of observed vibrational modes with pressure. Our hybrid functional band structure calculations predicted that phase I of Ag2Se would be a narrow band gap semiconductor, in accordance with experimental results. At a pressure of ~7.5 GPa, Ag2Se underwent a structural transition to phase II with an orthorhombic Pnma structure. The temperature dependence of the resistivity of Ag2Se phase II demonstrated its metallic character. Ag2Se phase III, which is stable above 16.5 GPa, is also metallic according to the resistivity data. No indication of the superconducting transition is found above 4 K in the studied pressure range. AU - Naumov, P AU - Barkalov, O AU - Mirhosseini, Hossein AU - Felser, C AU - A Medvedev, S ID - 19842 IS - 38 JF - Journal of Physics: Condensed Matter TI - Atomic and electronic structures evolution of the narrow band gap semiconductor Ag2Se under high pressure VL - 28 ER - TY - CONF AB - The provision of IT solutions over electronic marketplaces became prominent in recent years. We call such marketplaces IT service markets. IT service markets have some core architectural building blocks that impact the quality attributes of these markets. However, these building blocks and their impacts are not well-known. Thus, design choices for IT service markets have been made ad-hoc until now. Furthermore, only single aspects of such markets have been investigated until now, but a comprehensive view is missing.In this paper, we identify common features and their interrelations on the basis of a systematic literature review of 60 publications using grounded theory.This knowledge provides an empirical evidence on the interdisciplinary design choices of IT service markets and it serves as a basis to support market providers and developers to integrate market features. Thereby, we make a first step towards the creation of a reference model for IT service markets that provides a holistic integrated view that can be used to create and maintain successful markets in the future. AU - Jazayeri, Bahar AU - Platenius, Marie AU - Engels, Gregor AU - Kundisch, Dennis ID - 199 T2 - Proceedings of the 14th International Conference on Service Oriented Computing (ICSOC) TI - Features of IT Service Markets: A Systematic Literature Review VL - 9936 ER - TY - CONF AB - The self-organizing bio-hybrid collaboration ofrobots and natural plants allows for a variety of interestingapplications. As an example we investigate how robots can beused to control the growth and motion of a natural plant, using LEDs to provide stimuli. We follow an evolutionaryrobotics approach where task performance is determined bymonitoring the plant's reaction. First, we do initial plantexperiments with simple, predetermined controllers. Then weuse image sampling data as a model of the dynamics ofthe plant tip xy position. Second, we use this approach toevolve robot controllers in simulation. The task is to makethe plant approach three predetermined, distinct points in anxy-plane. Finally, we test the evolved controllers in real plantexperiments and find that we cross the reality gap successfully. We shortly describe how we have extended from plant tipto many points on the plant, for a model of the plant stemdynamics. Future work will extend to two-axes image samplingfor a 3-d approach. AU - Wahby, Mostafa AU - Hofstadler, Daniel Nicolas AU - Heinrich, Mary Katherine AU - Zahadat, Payam AU - Hamann, Heiko ID - 19961 SN - 9781509035342 T2 - Proc. of the 10th International Conference on Self-Adaptive and Self-Organizing Systems TI - An Evolutionary Robotics Approach to the Control of Plant Growth and Motion: Modeling Plants and Crossing the Reality Gap ER - TY - CONF AU - Heinrich, Mary Katherine AU - Wahby, Mostafa AU - Divband Soorati, Mohammad AU - Hofstadler, Daniel Nicolas AU - Zahadat, Payam AU - Ayres, Phil AU - Stoy, Kasper AU - Hamann, Heiko ID - 19968 SN - 9781509036516 T2 - Proc. of the 1st International Workshop on Self-Organising Construction (SOCO) TI - Self-Organized Construction with Continuous Building Material: Higher Flexibility Based on Braided Structures ER - TY - JOUR AU - Hamann, Heiko AU - Khaluf, Yara AU - Botev, Jean AU - Divband Soorati, Mohammad AU - Ferrante, Eliseo AU - Kosak, Oliver AU - Montanier, Jean-Marc AU - Mostaghim, Sanaz AU - Redpath, Richard AU - Timmis, Jon AU - Veenstra, Frank AU - Wahby, Mostafa AU - Zamuda, Aleš ID - 19969 JF - Frontiers in Robotics and AI SN - 2296-9144 TI - Hybrid Societies: Challenges and Perspectives in the Design of Collective Behavior in Self-organizing Systems ER - TY - CONF AU - Hamann, Heiko AU - Divband Soorati, Mohammad ID - 19979 T2 - IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016) TI - Robot Self-Assembly as Adaptive Growth Process: Collective Selection of Seed Position and Self-Organizing Tree-Structures ER - TY - JOUR AU - Dorigo, Marco AU - Hamann, Heiko AU - Valentini, Gabriele AU - Ferrante, Eliseo ID - 19983 IS - 3 JF - Journal of Autonomous Agents and Multi-Agent Systems TI - Collective Decision with 100 Kilobots: Speed vs Accuracy in Binary Discrimination Problems VL - 30 ER - TY - THES AU - Drees, Maximilian ID - 200 TI - Existence and Properties of Pure Nash Equilibria in Budget Games ER - TY - CONF AU - Hamann, Heiko AU - Valentini, Gabriele AU - Dorigo, Marco ID - 20000 SN - 0302-9743 T2 - 10th Int. Conf. on Swarm Intelligence, ANTS 2016 TI - Population Coding: A New Design Paradigm for Embodied Distributed Systems ER - TY - CONF AU - von Mammen, Sebastian AU - Hamann, Heiko AU - Heider, Michael ID - 20001 SN - 9781450344913 T2 - ACM Symposium on Virtual Reality Software and Technology (VRST) TI - Robot Gardens: An Augmented Reality Prototype for Plant-Robot Biohybrid Systems ER -