University of Applied Sciences and Arts Southern Switzerland

www.supsi.ch
Canobbio, Switzerland

The University of Applied science and Arts of Southern Switzerland is one of the Universities of Applied science of the Swiss Confederation.SUPSI offers more than 30 bachelor and master courses, complementing theoretical scientific knowledge and practical technological advances applied to real projects.Various departments of SUPSI are based in Southern Switzerland, mainly near Lugano. Wikipedia.

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Bochicchio D.,University of Applied Sciences and Arts Southern Switzerland | Pavan G.M.,University of Applied Sciences and Arts Southern Switzerland
ACS Nano | Year: 2017

Supramolecular polymers, formed via noncovalent self-assembly of elementary monomers, are extremely interesting for their dynamic bioinspired properties. In order to understand their behavior, it is necessary to access their dynamics while maintaining high resolution in the treatment of the monomer structure and monomer-monomer interactions, which is typically a difficult task, especially in aqueous solution. Focusing on 1,3,5-benzenetricarboxamide (BTA) water-soluble supramolecular polymers, we have developed a transferable coarse-grained model that allows studying BTA supramolecular polymerization in water, while preserving remarkable consistency with the atomistic models in the description of the key interactions between the monomers (hydrophobic, H-bonding, etc.), self-assembly cooperativity, and amplification of order into the growing fibers. This permitted us to monitor the amplification of the key interactions between the monomers (including H-bonding) in the BTA fibers during the dynamic polymerization process. Our molecular dynamics simulations provide a picture of a stepwise cooperative polymerization mechanism, where initial fast hydrophobic aggregation of the BTA monomers in water is followed by the slower reorganization of these disordered aggregates into ordered directional oligomers. Supramolecular polymer growth then proceeds on a slower time scale. We challenged our models via comparison with the experimental evidence, capturing the effect of temperature variations and subtle changes in the monomer structure on the polymerization and on the properties of the fibers seen in the real systems. This work provides a multiscale spatiotemporal characterization of BTA self-assembly in water and a useful platform to study a variety of BTA-based supramolecular polymers toward structure-property relationships. © 2016 American Chemical Society.


Grandoni F.,University of Applied Sciences and Arts Southern Switzerland | Laekhanukit B.,Weizmann Institute of Science
Proceedings of the Annual ACM Symposium on Theory of Computing | Year: 2017

Real-word networks are often prone to failures. A reliable network needs to cope with this situation and must provide a backup communication channel. This motivates the study of survivable network design, which has been a focus of research for a few decades. To date, survivable network design problems on undirected graphs are well-understood. For example, there is a 2 approximation in the case of edge failures [Jain, FOCS'98/Combinatorica'01]. The problems on directed graphs, in contrast, have seen very little progress. Most techniques for the undirected case like primal-dual and iterative rounding methods do not seem to extend to the directed case. Almost no non-trivial approximation algorithm is known even for a simple case where we wish to design a network that tolerates a single failure. In this paper, we study a survivable network design problem on directed graphs, 2-Connected Directed Steiner Tree (2-DST): given an n-vertex weighted directed graph, a root r, and a set of h terminals S, find a min-cost subgraph H that has two edge/vertex disjoint paths from r to any t ∈ S. 2-DST is a natural generalization of the classical Directed Steiner Tree problem (DST), where we have an additional requirement that the network must tolerate one failure. No non-trivial approximation is known for 2-DST. This was left as an open problem by Feldman et al., [SODA'09; JCSS] and has then been studied by Cheriyan et al. [SODA 12; TALG] and Laekhanukit [SODA'14]. However, no positive result was known except for the special case of a D-shallow instance [Laekhanukit, ICALP'16]. We present an O(D3 log D·h2/D · log n) approximation algorithm for 2-DST that runs in timeO(nO(D)), for any D ∈ [log2 h]. This implies a polynomial-time O(hϵ log n) approximation for any constant ϵ > 0, and a poly-logarithmic approximation running in quasipolynomial time. We remark that this is essentially the best-known even for the classical DST, and the latter problem is O(log2-ϵ n)-hard to approximate [Halperin and Krauthgamer, STOC'03]. As a by product, we obtain an algorithm with the same approximation guarantee for the 2-Connected Directed Steiner Subgraph problem, where the goal is to find a min-cost subgraph such that every pair of terminals are 2-edge/vertex connected. Our approximation algorithm is based on a careful combination of several techniques. In more detail, we decompose an optimal solution into two (possibly not edge disjoint) divergent trees that induces two edge disjoint paths from the root to any given terminal. These divergent trees are then embedded into a shallow tree by means of Zelikovsky's height reduction theorem. On the latter tree we solve a 2-Connected Group Steiner Tree problem and then map back this solution to the original graph. Crucially, our tree embedding is achieved via a probabilistic mapping guided by an LP: This is the main technical novelty of our approach, and might be useful for future work. © 2017 ACM.


Virtuani A.,University of Applied Sciences and Arts Southern Switzerland | Fanni L.,University of Applied Sciences and Arts Southern Switzerland
Progress in Photovoltaics: Research and Applications | Year: 2014

Several works report on seasonal fluctuations of power production of amorphous silicon (a-Si). These oscillations are due to two overlapping phenomena (i) spectral and (ii) the Staebler-Wronski effects. It is hence difficult to assess - for a given location and climatic conditions - which one has the largest impact. By means of a straightforward approach based on two sets of single-junction a-Si photovoltaic modules (stored indoors/exposed outdoors) and on two different I-V measurement set-ups (indoor and outdoor), we were able to separate the different contributions to this phenomenon. For the test-site of Lugano, seasonal oscillations account for performance variations of a-Si of ~10% (±5% around an annual average value with a minimum around the mid of January and a maximum around mid-July). The time-phase of the overall effect lies in between that of the two distinguished phenomena. (i) Spectral variations seem to have the highest impact on the outdoor performance of a-Si with an amplitude corresponding to 10.5% (± ~5.2%). Moreover, the influence of spectral variations on the outdoor performance of a-Si (and for comparison of c-Si) was modeled, and the experimental data were found to be in excellent agreement with the theoretical simulation; (ii) the Staebler-Wronski effect has a slightly lower influence with an amplitude of ~8% (±4% with a minimum at the middle of February and a maximum around mid-August). Because of the position (46°N) and average climatic conditions (southern Alpine climate) of Lugano, these observations are possibly representative of a large part of continental Europe. Copyright © 2012 John Wiley & Sons, Ltd. Several works report on seasonal fluctuations of power production of amorphous silicon (a-Si). These oscillations are due to two overlapping phenomena (i) spectral and (ii) the Staebler-Wronski effects. In this work, we separate between the different contributions to this phenomenon. For the test-site of Lugano (46°N), seasonal oscillations account for performance variations of a-Si of ~10% (±5% around an annual average value with a minimum around the mid of January and a maximum around mid-July). The time-phase of the overall effect lies in between that of the two distinguished phenomena. (i) Spectral variations seem to have the highest impact on the outdoor performance of a-Si with an amplitude corresponding to 10.5% (± ~5.2%); (ii) the Staebler-Wronski effect has a slightly lower influence with an amplitude of ~8% (±4% with a minimum at the middle of February and a maximum around mid-August). Copyright © 2012 John Wiley & Sons, Ltd.


Lim J.,Texas Christian University | Pavan G.M.,University of Applied Sciences and Arts Southern Switzerland | Annunziata O.,Texas Christian University | Simanek E.E.,Texas Christian University
Journal of the American Chemical Society | Year: 2012

The synthesis, characterization, and host-guest chemistry of high-generation triazine dendrimers are described. With pyrene and camptothecin as guests, experiments revealed that the guest capacity of odd-generation triazine dendrimers increased until generation 7 but decreased at generation 9. Molecular dynamics simulations conducted in explicit solvent showed a useful fingerprint for this behavior in radial distribution functions of water molecules penetrating the interior of the dendrimers. A linear relationship between the guest capacity of dendrimers measured experimentally and the number of water molecules within the interior determined computationally was observed. © 2012 American Chemical Society.


Conti M.,National Research Council Italy | Giordano S.,University of Applied Sciences and Arts Southern Switzerland
IEEE Communications Magazine | Year: 2014

In this article we discuss the state of the art of (mobile) multihop ad hoc networking. This paradigm has often been identified with the solutions developed inside the IETF MANET working group, and for this reason it is called the MANET paradigm. However, they do not coincide, and in the last decade they clearly diverged. In this article, we start from the reasons why the MANET paradigm did not have a major impact on computer communications, and we discuss the evolution of the multihop ad hoc networking paradigm by building on the lessons learned from the MANET research. Specifically, we analyze four successful networking paradigms, mesh, sensor, opportunistic, and vehicular networks, that emerged from the MANET world as a more pragmatic application of the multihop ad hoc networking paradigm. We also present the new research directions in the multihop ad hoc networking field: peoplecentric networking, triggered by the increasing penetration of the smartphones in everyday life, which is generating a people-centric revolution in computing and communications. © 2014 IEEE.


Pavan G.M.,University of Applied Sciences and Arts Southern Switzerland
ChemMedChem | Year: 2014

Cationic dendrimers are promising nanocarriers for gene delivery thanks to their ability to establish strong interactions with oppositely charged strands of DNA and siRNA and to promote their aggregation. The binding between dendrimers and nucleic acids is typically a complex process that involves various types of interactions at different scales. To design efficient dendrimer candidates for DNA and siRNA binding it is necessary to have a detailed understanding of their interactions with oligonucleotides in the solvent. Molecular simulation can support experimental work, providing a privileged point of view on the aggregation process. This Minireview discusses recent computational efforts to unravel dendrimer-oligonucleotide binding, and proposes a perspective of the multiscale aggregation process based on hierarchy and on the transformations of the interacting "molecular units" following intermolecular interactions. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Nguyen H.A.,University of Applied Sciences and Arts Southern Switzerland | Giordano S.,University of Applied Sciences and Arts Southern Switzerland
Ad Hoc Networks | Year: 2012

Context information can be used to streamline routing decisions in opportunistic networks. We propose a novel social context-based routing scheme that considers both the spatial and the temporal dimensions of the activity of mobile nodes to predict the mobility patterns of nodes based on the BackPropagation Neural Networks model. © 2011 Elsevier B.V. All rights reserved.


Kulkarni R.V.,Missouri University of Science and Technology | Forster A.,University of Applied Sciences and Arts Southern Switzerland | Venayagamoorthy G.K.,Missouri University of Science and Technology
IEEE Communications Surveys and Tutorials | Year: 2011

Wireless sensor networks (WSNs) are networks of distributed autonomous devices that can sense or monitor physical or environmental conditions cooperatively. WSNs face many challenges, mainly caused by communication failures, storage and computational constraints and limited power supply. Paradigms of computational intelligence (CI) have been successfully used in recent years to address various challenges such as data aggregation and fusion, energy aware routing, task scheduling, security, optimal deployment and localization. CI provides adaptive mechanisms that exhibit intelligent behavior in complex and dynamic environments like WSNs. CI brings about flexibility, autonomous behavior, and robustness against topology changes, communication failures and scenario changes. However, WSN developers are usually not or not completely aware of the potential CI algorithms offer. On the other side, CI researchers are not familiar with all real problems and subtle requirements of WSNs. This mismatch makes collaboration and development difficult. This paper intends to close this gap and foster collaboration by offering a detailed introduction to WSNs and their properties. An extensive survey of CI applications to various problems in WSNs from various research areas and publication venues is presented in the paper. Besides, a discussion on advantages and disadvantages of CI algorithms over traditional WSN solutions is offered. In addition, a general evaluation of CI algorithms is presented, which will serve as a guide for using CI algorithms for WSNs. © 2005 IEEE.


Sergi D.,University of Applied Sciences and Arts Southern Switzerland
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

The Landauer-Büttiker formalism provides a simple and insightful way for investigating many phenomena in mesoscopic physics. By this approach we derive general formulas for the energy currents and apply them to the basic setups. Of particular interest are the noise properties. We show that energy current fluctuations can be induced by zero-point fluctuations, and we discuss the implications of this result. © 2011 The American Physical Society.


Patent
University of Applied Sciences and Arts Southern Switzerland | Date: 2011-07-11

A flotation clarification system (1) for wastewater includes: at least one main tank (2) defining a vertical central axis and having a bottom (3) at least a lateral wall (4); at least one sludge collecting device (5) for sludge to be treated; at least one unit (20) for adding air bubbles to water and/or sludge to be treated; and at least one water retaining tank (31). The unit (20) for adding air bubbles includes: at least one duct (33) for a flow of water and/or sludge to be treated; at least one duct (34) for a flow of water added with air; and at least one mixing device (35) configured and dimensioned so that the flow of water added with air is positioned inside the flow of water and/or sludge to be treated and runs into the latter while expanding radially from the inside towards the outside or vice versa.

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