Structural diversity in tetrakis(4-pyridyl)porphyrin supramolecular building blocks

The authors would like to thank the University of Alabama Department of Chemistry and the University of Missouri-Columbia Department of Chemistry for support of this work.In memory of a pioneer in crystal engineering, Prof. Israel Goldberg, we report a series of new framework solids, based on the ligand tetrakis(4–pyridyl)porphyrin (TPyP). Spontaneous reactions of TPyP with seven different metal salts under liquid-liquid diffusion at ambient temperature show that the formation of ionic compounds is preferred to coordination polymers due to increased conformational freedom. Two coordination networks, {(HgI2)2(TPyP)}n·4nCHCl3∙2nTCE (TCE = 1,1,2,2–tetrachloroethane), and {(Ba(μ1,1–NCS)(μ1,1,3–NCS)(H2O)(MeCN))2(TPyP)}n·4nH2O, displayed a new isomeric form of the known [(HgI2)2(TPyP)]∞ polymeric motif, and a two-dimensional honeycomb polymeric motif linked by hydrogen-bonding into a three dimensional moganite (mog) net, respectively. Four protonated porphyrinic salts, [H3TPyP][PF6]3∙0.5TCE, [H2TPyP][I3]2·2MeOH, [H4TPyP][UO2Cl4]2·6MeCN, and [H4TPyP][Th(NO3)6][NO3]2, were observed which hydrogen bond to give one- or two-dimensional networks, or in the case of [H4TPyP][UO2Cl4]2·6MeCN, a discrete dinuclear hydrogen-bonded complex. In one case, a neutral, hydrogen-bonded complex, Ce(NO3)3(MeOH)3(H2O)·TPyP·TCE·H2O, was formed which adopts a three-dimensional, self-penetrated variant of the face-centered cubic (fcc) network. These new structures represent hybrid organic-inorganic crystalline compounds in which the multidentate porphyrin units, having both hydrogen bonding, as well as coordination functionalities, are interlinked through the inorganic connectors into self-assembled three-dimensional architectures. This work shows the relative stability of noncovalently bound vs. coordination networks as well as the effective potential of the TPyP building block to construct supramolecular assemblies in the presence or absence of coordinating ions as linkers.PostprintPeer reviewe

QoS Provisioning in Converged Satellite and Terrestrial Networks: A Survey of the State-of-the-Art

It has been widely acknowledged that future networks will need to provide significantly more capacity than current ones in order to deal with the increasing traffic demands of the users. Particularly in regions where optical fibers are unlikely to be deployed due to economical constraints, this is a major challenge. One option to address this issue is to complement existing narrow-band terrestrial networks with additional satellite connections. Satellites cover huge areas, and recent developments have considerably increased the available capacity while decreasing the cost. However, geostationary satellite links have significantly different link characteristics than most terrestrial links, mainly due to the higher signal propagation time, which often renders them not suitable for delay intolerant traffic. This paper surveys the current state-of-the-art of satellite and terrestrial network convergence. We mainly focus on scenarios in which satellite networks complement existing terrestrial infrastructures, i.e., parallel satellite and terrestrial links exist, in order to provide high bandwidth connections while ideally achieving a similar end user quality-of-experience as in high bandwidth terrestrial networks. Thus, we identify the technical challenges associated with the convergence of satellite and terrestrial networks and analyze the related work. Based on this, we identify four key functional building blocks, which are essential to distribute traffic optimally between the terrestrial and the satellite networks. These are the traffic requirement identification function, the link characteristics identification function, as well as the traffic engineering function and the execution function. Afterwards, we survey current network architectures with respect to these key functional building blocks and perform a gap analysis, which shows that all analyzed network architectures require adaptations to effectively support converged satellite and terrestrial networks. Hence, we conclude by formulating several open research questions with respect to satellite and terrestrial network convergence.This work was supported by the BATS Research Project through the European Union Seventh Framework Programme under Contract 317533

Federation of Cyber Ranges

Küberkaitse võimekuse aluselemendiks on kõrgete oskustega ja kokku treeninud spetsialistid. Tehnikute, operaatorite ja otsustajate teadlikkust ja oskusi saab treenida läbi rahvusvaheliste õppuste. On mõeldamatu, et kaitse ja rünnakute harjutamiseks kasutatakse toimivat reaalajalist organisatsiooni IT-süsteemi. Päriseluliste süsteemide simuleerimiseks on võimalik kasutada küberharjutusväljakuid.NATO ja Euroopa Liidu liikmesriikides on mitmed juba toimivad ja käimasolevad arendusprojektid uute küberharjutusväljakute loomiseks. Et olemasolevast ressurssi täies mahus kasutada, tuleks kõik sellised harjutusväljakud rahvusvaheliste õppuste tarbeks ühendada. Ühenduvus on võimalik saavutada alles pärast kokkuleppeid, tehnoloogiate ja erinevate harjutusväljakute kitsenduste arvestamist.Antud lõputöö vaatleb kahte küberharjutusväljakut ja uurib võimalusi, kuidas on võimalik rahvuslike harjutusväljakute ressursse jagada ja luua ühendatud testide ja õppuste keskkond rahvusvahelisteks küberkaitseõppusteks. Lõputöö annab soovitusi informatsiooni voogudest, testkontseptsioonidest ja eeldustest, kuidas saavutada ühendused ressursside jagamise võimekusega. Vaadeldakse erinevaid tehnoloogiad ja operatsioonilisi aspekte ning hinnatakse nende mõju.Et paremini mõista harjutusväljakute ühendamist, on üles seatud testkeskkond Eesti ja Tšehhi laborite infrastruktuuride vahel. Testiti erinevaid võrguparameetreid, operatsioone virtuaalmasinatega, virtualiseerimise tehnoloogiad ning keskkonna haldust avatud lähtekoodiga tööriistadega. Testide tulemused olid üllatavad ja positiivsed, muutes ühendatud küberharjutusväljakute kontseptsiooni saavutamise oodatust lihtsamaks.Magistritöö on kirjutatud inglise keeles ja sisaldab teksti 42 leheküljel, 7 peatükki, 12 joonist ja 4 tabelit.Võtmesõnad:Küberharjutusväljak, NATO, ühendamine, virtualiseerimine, rahvusvahelised küberkaitse õppusedAn essential element of the cyber defence capability is highly skilled and well-trained personnel. Enhancing awareness and education of technicians, operators and decision makers can be done through multinational exercises. It is unthinkable to use an operational production environment to train attack and defence of the IT system. For simulating a life like environment, a cyber range can be used. There are many emerging and operational cyber ranges in the EU and NATO. To benefit more from available resources, a federated cyber range environment for multinational cyber defence exercises can be built upon the current facilities. Federation can be achieved after agreements between nations and understanding of the technologies and limitations of different national ranges.This study compares two cyber ranges and looks into possibilities of pooling and sharing of national facilities and to the establishment of a logical federation of interconnected cyber ranges. The thesis gives recommendations on information flow, proof of concept, guide-lines and prerequisites to achieve an initial interconnection with pooling and sharing capabilities. Different technologies and operational aspects are discussed and their impact is analysed. To better understand concepts and assumptions of federation, a test environment with Estonian and Czech national cyber ranges was created. Different aspects of network parameters, virtual machine manipulations, virtualization technologies and open source administration tools were tested. Some surprising and positive outcomes were in the result of the tests, making logical federation technologically easier and more achievable than expected.The thesis is in English and contains 42 pages of text, 7 chapters, 12 figures and 4 tables.Keywords:Cyber Range, NATO, federation, virtualization, multinational cyber defence exercise

Heteroleptic samarium(III) halide complexes probed by fluorescence-detected L3-edge X-ray absorption spectroscopy

Addition of various oxidants to the near-linear Sm(II) complex [Sm(N††)2] (1), where N†† is the bulky bis(triisopropylsilyl)amide ligand {N(SiiPr3)2}, afforded a family of heteroleptic three-coordinate Sm(III) halide complexes, [Sm(N††)2(X)] (X = F, 2-F; Cl, 2-Cl; Br, 2-Br; I, 2-I). In addition, the trinuclear cluster [{Sm(N††)}3(μ2-I)3(μ3-I)2] (3), which formally contains one Sm(II) and two Sm(III) centres, was isolated during the synthesis of 2-I. Complexes 2-X are remarkably stable towards ligand redistribution, which is often a facile process for heteroleptic complexes of smaller monodentate ligands in lanthanide chemistry, including the related bis(trimethylsilyl)amide {N(SiMe3)2} (N′′). Complexes 2-X and 3 have been characterised by single crystal X-ray diffraction, elemental analysis, multinuclear NMR, FTIR and electronic spectroscopy. The Lα1 fluorescence-detected X-ray absorption spectrum recorded at the Sm L3-edge for 2-X exhibited a resolved pre-edge peak defined as an envelope quadrupole-allowed 2p → 4f transition. The X-ray absorption spectral features were successfully reproduced using time-dependent density functional theoretical (TD-DFT) calculations that synergistically supports the experimental observations as well as the theoretical model upon which the electronic structure and bonding in lanthanide complexes is derived

MMBnet 2017 - Proceedings of the 9th GI/ITG Workshop „Leistungs-, Verlässlichkeits- und Zuverlässigkeitsbewertung von Kommunikationsnetzen und Verteilten Systemen“

Nowadays, mathematical methods of systems and network monitoring, modeling, simulation, and performance, dependability and reliability analysis constitute the foundation of quantitative evaluation methods with regard to software-defined next-generation networks and advanced cloud computing systems. Considering the application of the underlying methodologies in engineering practice, these sophisticated techniques provide the basis in many different areas. The GI/ITG Technical Committee “Measurement, Modelling and Evaluation of Computing Systems“ (MMB) and its members have investigated corresponding research topics and initiated a series of MMB conferences and workshops over the last decades. Its 9th GI/ITG Workshop MMBnet 2017 „Leistungs-, Verlässlichkeits- und Zuverlässigkeitsbewertung von Kommunikationsnetzen und Verteilten Systemen“ was held at Hamburg University of Technology (TUHH), Germany, on September 14, 2017. The proceedings of MMBnet 2017 summarize the contributions of one invited talk and four contributed papers of young researchers. They deal with current research issues in next-generation networks, IP-based real-time communication systems, and new application architectures and intend to stimulate the reader‘s future research in these vital areas of modern information society