Systems In Different Fields Research Articles

Identifying Strong Covalent Interactions with Pauli Energy.

As one of the most widely used chemical concepts whose origin can be traced back to Lewis theory of bonding a century ago, a covalent bond involves sharing one or more pairs of electrons between atoms. A strong covalent interaction (SCI) is such a covalent bond that two or more electron pairs are shared, yielding a double, triple, quadruple, or even higher bond order. Despite its ubiquity and usefulness, a robust and generally applicable approach to accurately identify strong covalent interactions and determine their bond orders is still lacking. In this work, an SCI index is proposed from density functional theory using the Pauli energy, which is the contribution of the Pauli exclusion principle to the kinetic energy. Illustrative examples from organic, inorganic, and organometallic systems were provided. Its close relationship with the electron localization function (ELF) was elucidated. Both ELF and SCI generate similar results. Two complexes with a quintuple metal-metal bond have been confirmed. A stronger than quintuple bond has been showcased. This work should provide a robust approach to determine bond orders for strong covalent interactions in complex systems, pinpoint the physiochemical origin of strong covalent interactions, and rationalize the usefulness of both SCI and ELF. These tools should be able to be applied to other systems in different fields to effectively appreciate strong covalent interactions.

The Usage of Social Media and E-Reputation System in Global Supply Chain: Comparative Cases from Diamond & Automotive Industries

The last decade witnesses a heave use of social media-based information systems in different fields of business such as logistics, procurement, and supply chain management. Managing these types of information systems, could help companies to outsource their supply chain functions in a global scale and enhance their competitive advantages. However, the digital performance of these activities inherent risks of inappropriate supplier selection, lack of trust, bounded rationality and uncertainty about the supply conditions (e.g., pricing, shipping and timing). To address such challenges, this research explains how companies use e-reputation systems and social media to select their global trusted suppliers. Based on two-case evidence from British Diamond and Egyptian Automotive companies, the researchers conducted 20 interviews with purchasing and supply chain professionals. Chen & Lin’s reputation system model has been adopted to explain the process of selecting and evaluating a trusted supplier and to inform our data analysis. Our findings referred to the lack of experience among diamond professionals on how to use e-reputation systems and their lack of understanding to the role of social media-based ratings or referrals during the stages of selection suppliers’ discovery and approval. Though, automotive professionals find e-reputation system a strong tool to build goodwill, tacit credibility, competence and predictable trust. Ironically, both cases confirm that supply chain professional use these systems to re-evaluate and reselect their existing suppliers than to extend new supply networks.

Distributed simulation optimization and parameter exploration framework for the cloud

Simulation models are becoming an increasingly popular tool for the analysis and optimization of complex real systems in different fields. Finding an optimal system design requires performing a large sweep over the parameter space in an organized way. Hence, the model optimization process is extremely demanding from a computational point of view, as it requires careful, time-consuming, complex orchestration of coordinated executions. In this paper, we present the design of SOF (Simulation Optimization and exploration Framework in the cloud), a framework which exploits the computing power of a cloud computational environment in order to carry out effective and efficient simulation optimization strategies. SOF offers several attractive features. Firstly, SOF requires “zero configuration”, as it does not require any additional software installed on the remote node; only standard Apache Hadoop and SSH access are sufficient. Secondly, SOF is transparent to the user, since the user is totally unaware that the system operates on a distributed environment. Finally, SOF is highly customizable and programmable, since it enables the running of different simulation optimization scenarios using diverse programming languages – provided that the hosting platform supports them – and different simulation toolkits, as developed by the modeler. The tool has been fully developed and is available on a public repository11SOF GitHub public repository, https://github.com/isislab-unisa/sof. under the terms of the open source Apache License. It has been tested and validated on several private platforms, such as a dedicated cluster of workstations, as well as on public platforms, including the Hortonworks Data Platform and Amazon Web Services Elastic MapReduce solution.

Microporous Hyper-Crosslinked Polystyrenes and Nanocomposites with High Adsorption Properties: A Review.

Hyper-crosslinked (HCL) polystyrenes show outstanding properties, such as high specific surface area and adsorption capability. Several researches have been recently focused on tailoring their performance for specific applications, such as gas adsorption and separation, energy storage, air and water purification processes, and catalysis. In this review, main strategies for the realization of HCL polystyrene-based materials with advanced properties are reported, including a summary of the synthetic routes that are adopted for their realization and the chemical modification approaches that are used to impart them specific functionalities. Moreover, the most up to date results on the synthesis of HCL polystyrene-based nanocomposites that are realized by embedding these high surface area polymers with metal, metal oxide, and carbon-based nanofillers are discussed in detail, underlining the high potential applicability of these systems in different fields.

The new challenges of multiplex networks: Measures and models

What do societies, the Internet, and the human brain have in common? They are all examples of complex relational systems, whose emerging behaviours are largely determined by the non-trivial networks of interactions among their constituents, namely individuals, computers, or neurons, rather than only by the properties of the units themselves. In the last two decades, network scientists have proposed models of increasing complexity to better understand real-world systems. Only recently we have realised that multiplexity, i.e. the coexistence of several types of interactions among the constituents of a complex system, is responsible for substantial qualitative and quantitative differences in the type and variety of behaviours that a complex system can exhibit. As a consequence, multilayer and multiplex networks have become a hot topic in complexity science. Here we provide an overview of some of the measures proposed so far to characterise the structure of multiplex networks, and a selection of models aiming at reproducing those structural properties and quantifying their statistical significance. Focusing on a subset of relevant topics, this brief review is a quite comprehensive introduction to the most basic tools for the analysis of multiplex networks observed in the real-world. The wide applicability of multiplex networks as a framework to model complex systems in different fields, from biology to social sciences, and the colloquial tone of the paper will make it an interesting read for researchers working on both theoretical and experimental analysis of networked systems.

Towards on-the-fly data post-processing for real-time tomographic imaging at TOMCAT

Sub-second full-field tomographic microscopy at third-generation synchrotron sources is a reality, opening up new possibilities for the study of dynamic systems in different fields. Sustained elevated data rates of multiple GB/s in tomographic experiments will become even more common at diffraction-limited storage rings, coming in operation soon. The computational tools necessary for the post-processing of raw tomographic projections have generally not experienced the same efficiency increase as the experimental facilities, hindering optimal exploitation of this new potential. We present here a fast, flexible, and user-friendly post-processing pipeline overcoming this efficiency mismatch and delivering reconstructed tomographic datasets just few seconds after the data have been acquired, enabling fast parameter and image quality evaluation as well as efficient post-processing of TBs of tomographic data. With this new tool, also able to accept a stream of data directly from a detector, few selected tomographic slices are available in less than half a second, providing advanced previewing capabilities paving the way to new concepts for on-the-fly control of dynamic experiments.

An Overview of the Main Topics and Applications of Graph Theoretic Problems in Multiphysics Engineering

Graph-theoretic concepts are mostly used to study different applications in various areas such as electrical and mechanical engineering, generally multi-physics systems. The interest of researchers on this theory has importantly increased in the last decade. The main goal of this paper is to provide an overview of the use and applications of graph theoretic concept in modelling and analysis of systems in different fields. Therefore, the research topics discussed in this review are going to respect all the mentioned domains and the countries that apply this theory formulation in addition to the community of researchers who are identified by their publishers.

AntStar: Enhancing Optimization Problems by Integrating an Ant System andA⁎Algorithm

Recently, nature-inspired techniques have become valuable to many intelligent systems in different fields of technology and science. Among these techniques, Ant Systems (AS) have become a valuable technique for intelligent systems in different fields. AS is a computational system inspired by the foraging behavior of ants and intended to solve practical optimization problems. In this paper, we introduce the AntStar algorithm, which is swarm intelligence based. AntStar enhances the optimization and performance of an AS by integrating the AS andA⁎algorithm. Applying the AntStar algorithm to the single-source shortest-path problem has been done to ensure the efficiency of the proposed AntStar algorithm. The experimental result of the proposed algorithm illustrated the robustness and accuracy of the AntStar algorithm.

Análise bidimensional do processo de fusão de um material de mudança de fase em uma cavidade retangular

Os materiais de mudança de fase podem ser utilizados em sistemas de armazenamento térmico de diferentes áreas da indústria, desta forma, a sua utilização nos sistemas de armazenamento de energia térmica apresenta-se como uma alternativa interessante para a otimização de uma grande gama de processos industriais. Levando em conta o aspecto inovador da utilização dos materiais de mudança de fase para armazenar/liberar energia na forma de calor latente, objetivou-se neste estudo, analisar numericamente o processo de fusão do eritritol contido em uma cavidade retangular, isto levando em conta a influência de variáveis geométricas, bem como, a temperatura a qual o sistema está submetido. O software comercial ANSYS FLUENT-14, foi utilizado para a execução de todas as simulações numéricas, em regime transiente, necessárias para a resolução do problema apresentado. Diferentes critérios de convergência foram adotados em todas as simulações realizadas. Dois tipos de validação numérica foram aqui realizadas, sendo estas: validação qualitativa e validação quantitativa. Resultados obtidos demonstram que a altura da cavidade não influencia de forma significativamente o tempo de derretimento do material utilizado, contudo, uma grande influência da temperatura da parede de aquecimento foi encontrada no tempo necessário para a completa fusão do material.

A METHOD FOR INCORPORATING FRACTIONAL-ORDER DYNAMICS THROUGH PID CONTROL SYSTEM RETUNING

Proportional-Integral-Derivative (PID) controllers have been the heart of control systems engineering practice for decades because of its sim- plicity and ability to satisfactory control different types of systems in different fields of science and engineering in general. It has receive widespread attention both in the academe and industry that made these controllers very mature and

Noise-induced intermittency of a reflexive model with symmetry-induced equilibrium manifold

We discuss a route to intermittency based on the concept of reflexivity, namely on the interaction between observer and stochastic reality. A simple model mirroring the essential aspects of this interaction is shown to generate perennial out of equilibrium condition, intermittency and 1/f-noise. In the absence of noise the model yields a symmetry-induced equilibrium manifold with two stable states. Noise makes this equilibrium manifold unstable, with an escape rate becoming lower and lower upon time increase, thereby generating an inverse power law distribution of waiting times. The distribution of the times of permanence in the basin of attraction of the equilibrium manifold are analytically predicted through the adoption of a first-passage time technique. Finally we discuss the possible extension of our approach to deal with the intermittency of complex systems in different fields.

Exact solution for a noncentral electric dipole ring-shaped potential in the tridiagonal representation

The Schrödinger equation with noncentral electric dipole ring-shaped potential is investigated by working in a complete square integrable basis that supports an infinite tridiagonal matrix representation of the wave operator. The three-term recursion relations for the expansion coefficients of both the angular and radial wavefunctions are presented. The discrete spectrum for the bound states is obtained by the diagonalization of the radial recursion relation. Some potential applications of this system in different fields are discussed.

Preface

The 13th International Symposium on Novel Aromatic Compounds (ISNA-13) was held in Luxembourg City, Grand-Duchy of Luxembourg, the smallest country so far hosting a conference of the ISNA series. It took place 19-24 July 2009 and was attended by 360 participants, mostly from academic institutions, representing 34 countries. The scientific program consisted of the Opening Plenary Lecture given by Prof. Jean-Marie Lehn (Institute of Science and Supramolecular Engineering and Louis Pasteur University, Strasbourg), the 2009 Nozoe Lecture presented by Prof. Atsuhiro Osuka (Kyoto University, Kyoto), 34 invited lectures, 26 oral communications, and 194 posters presented in two sessions. In a public lecture, vice rector Prof. Luciënne Blessing presented the activities of the recently founded University of Luxembourg. The organizing committee made a strong and successful effort to attract numerous graduate and undergraduate students to ISNA-13.The ISNA symposium series was launched by Prof. Tetsuo Nozoe in 1970 as the International Symposium on Nonbenzenoid Aromatic Compounds. Since then, the currently biennial conference rotates between Asia, North America, and Europe. As indicated by its present name, the focus of the symposium has broadened and is now set on new experimental and theoretical insights into the concept of aromaticity, synthesis and properties of novel aromatic compounds, as well as applications of π-conjugated systems in different fields of molecular science and technology. From a broader perspective, through interactions between participating scientists, ISNA conferences aim at the generation of new knowledge and its eventual application for the betterment of society.In line with the above, the organizers of ISNA-13 emphasized not only the traditional and fundamental aspects of novel aromatic compounds, such as their theory, synthesis, structure, and properties, but also their application in materials science. This included, for example, macrocycles, oligomers, and polymers and their optoelectronic properties, supramolecular chemistry based on aromatic functional modules, aromatics on surfaces, and molecular electronics based on aromatic units. The main subjects of the meeting that are covered in this Special Topic issue are as follows:- aromaticity and novel aromatic systems - theory- aromaticity and novel aromatic systems - experimental- fullerenes and concave aromatics- aromatic polymers and oligomers and their optoelectronic properties- supramolecular aromatic devices, switches, and machines- aromatics on surfaces, including graphene- optoelectronicsThe next conference, ISNA-14, will be chaired by Profs. Michael M. Haley (University of Oregon, Eugene) and Benjamin T. King (University of Nevada, Reno) and will be held in Eugene, OR, USA, 24-29 July 2011. ISNA-15 will be organized by Prof. Ken-Tsung Wong (National Taiwan University) in Taipei, Taiwan.François DiederichA. Dieter SchlüterCarlo ThilgenConference Editors

Roles in Information Systems: A Survey

Role-based approaches are emerging technologies in information system design and implementation. Roles have been acknowledged and applied in many fields for many years. Considering their increasing importance and applications in the development of various information systems, this paper intends to: 1) survey the literature relevant to role mechanisms and role-based systems in different fields and point out their motivations and contributions; 2) classify roles in such different contexts as modeling, designing, management, and collaboration; 3) identify the commonalities and differences among roles in different fields; and 4) point out the challenges, benefits, and future research areas of role-based systems.

A kind of collaboration–competition networks

We propose describing a kind of cooperation–competition systems by node-weighted bipartite graphs. In such systems the nodes can be divided into two types. One expresses a kind of activities, organizations or events, named “acts”; and another expresses the “actors” participating in some acts. In each act the actors basically show collaboration relationship with each other, however they play different roles in the cooperation. Usually every actor tries to play the most important role; therefore the role difference can be regarded as a kind of competition. The node weight usually signifies the role or “importance degree” of each actor. We propose using some statistical properties for the description of such kind of systems. The properties without considering node weight can describe the cooperation situation and configuration. The properties with node weight may describe the competition results. Two example systems are reported to show the description method and the corresponding empirical investigation results. One is the undergraduate elective network, and another the library network of Yangzhou University. The description method may be effective for the similar systems in different fields.

From the discrete kinetic theory to modelling open systems of active particles

This work deals with a methodological development of the kinetic theory for open systems of active particles with discrete states. It essentially refers to the derivation of mathematical tools which provide the guidelines for modelling open systems in different fields of applied sciences. After a description of closed systems, mathematical frameworks suitable for depicting the evolution of open systems are proposed. Finally, some research perspectives towards modelling are outlined.

Entangling Fiber Solitons: Quantum Noise Engineering for Interferometry and Communication

Many particle systems follow a complex time evolution. If system interactions are governed by nonlinear behavior, the theoretical description is often difficult to address. The nonlinear dynamics of some systems feature solitary waves or solitons, which are dynamically stable excitations. They come about whenever the ubiquitous dispersion of a wave is compensated for by some nonlinear, i.e., amplitude-dependent response. First observed in water, today solitons are known to appear in many systems in different fields of physics.

Electron Transfer Reactions in Micellar Systems

The influence of micelles on electron transfer processes is reviewed. The micelles modify the rate of electron transfer reactions by producing changes in all the relevant parameters controlling this rate; that is, through modification of the reorganization free energy, the reaction free energy, the nuclear dynamics and the strength of the coupling between the donor and the acceptor. Applications of studies on electron transfer reactions in micellar systems in different fields are presented.

Fiber-optic dielectric multilayer hydrophone for ultrasound detection

Fiber-tip sensors have proved to be useful for the investigation of ultrasonic signals since they, in principle, overcome some limitations of common piezoelectric hydrophones. A high damage threshold of the sensor is obtained, measurements are not disturbed by electromagnetic influences, and a high temporal and lateral resolution is possible. An optical hydrophone is presented that comprises a fiber tip coated with a dielectric multilayer system of the Fabry–Perot type. The acoustic pressure measurement using the sensor is based on the elastic deformation of the layer system by an incident ultrasonic wave and the detection of the induced change of the optical reflectance. Measurement results obtained by sensors with different layer numbers providing different sensitivities are shown, and the variation of the sensor characteristics depending on the size and shape of the fiber tip is investigated. The appearance of optical loss modulations caused by the stimulation of flexural waves in the fiber in certain measurement configurations is discussed. Several sensor designs are considered to improve the performance of the system in different fields of application, for instance the characterization of lithotripter shock waves, the investigation of cavitation phenomena, and the detection of ultrasound cw signals.

Isotopic Effects in the Self-diffusion Coefficient in an Equimolar Binary Mixture

In the last few years molecular dynamics has become a valuable tool in calculating the thermodynamical, structural and transport behaviour of a lot of many-particle systems in different fields of science and application. First the aims and essential features of molecular dynamics (MD) are described. In the second part self-diffusion coefficients of N2/CH4 mixtures for isotope substituted methanes in dependence on temperature, pressure, mass and diameter are calculated. Avoiding large computational efforts the calculations are performed by a kinetic hard sphere theory fitting the hard sphere diameters by MD runs.