Application of Complex Networks Theory in Urban Traffic Network Researches

Networks and Spatial Economics - Complex network theory is a multidisciplinary research direction of complexity science which has experienced a rapid surge of interest over the last two decades....     

Supercomputing of reducing sequenced bases in de novo sequencing of the human genome

The Journal of Supercomputing - DNA sequencing is one of the important sub-disciplines of bioinformatics, which has various applications in medicine, history, demography, and archaeology. De...     

Firefly-inspired algorithm for discrete optimization problems: An application to manufacturing cell formation

The canonical firefly algorithm is basically developed for continuous optimization problems. However, lots of practical problems are formulated as discrete optimization problems. The main purpose of this paper is to present the discrete firefly algorithm (DFA) to solve discrete optimization problems. In the DFA, we define a firefly's position in terms of changes of probabilities that will be in one state or the other. Then by using this metaheuristic algorithm, the manufacturing cell formation problem is solved. To illustrate the behavior of the proposed model and verify the performance of the algorithm, we introduce a number of numerical examples to illustrate the use of the foregoing algorithm. The performance evaluation shows the effectiveness of the DFA. The proposed metaheuristic algorithm should thus be useful to both researchers and practitioners.     

Effect of collaboration network structure on knowledge creation and technological performance: the case of biotechnology in Canada

Many of the novel ideas that lead to scientific publications or yield technological advances are the result of collaborations among scientists or inventors. Although various aspects of collaboration networks have been examined, the impact of many network characteristics on knowledge creation and innovation production remains unclear due to the inconsistency of the conclusions from various research studies. One such network structure, called small world, has recently attracted much theoretical attention as it has been suggested that it can enhance the information transmission efficiency among the network actors. However, the existing empirical studies have failed to provide consistent results regarding the effect of small-world network properties on network performance in terms of its scientific and technological productivity. In this paper, using the data on 29 years of journal publications and patents in the field of biotechnology in Canada, the network of scientists’ collaboration activities has been constructed based on their co-authorships in scientific articles. Various structural properties of this network have been measured and the relationships between the network structure and knowledge creation, and quantity and quality of technological performance have been examined. We found that the structure of the co-authorship network of Canadian biotechnology scientists has a significant effect on the knowledge and innovation production, but it produced no impact on the quality of patents generated by these scientists.     

Cloud point extraction for determination of Diazinon: Optimization of the effective parameters using Taguchi method

Since Diazinon is one of the organophosphorous compounds which are harmful for human organisms, a simple, sensitive and accurate testing method for extraction and determination of this pesticide is mandatory. In this project, Cloud Point Extraction (CPE) method was developed for determination of Diazinon in aqueous samples. CTAB (cetyl trimethyl ammonium bromide) was used as cationic surfactant to extract and preconcentrate of Diazinon at the same time and the extracted Diazinon was determined by UV spectrophotometery. Taguchi L₉ array was employed for design of experiments to investigate influences of surfactant concentration, salt concentration, temperature and incubation time as effective parameters. According to the analysis of variance (ANOVA) results, the most effective parameter of the process is incubation time. The results show that a surfactant concentration of 10^− 5% (w/v), an incubation time of 30 min, a KI concentration of 10^− 6 mol L^− 1 and a temperature of 35 °C are the best operating conditions. Also, the linear calibration graph in the range of 0.02-24 ng ml^− 1 of Diazinon with r = 0.999 was obtained. The limit of detection (LOD) was 0.02 ng ml^− 1 and relative standard deviation (RSD) for 15 ng ml^− 1 of Diazinon was 0.76%.     

Cascading Wafer-Scale Integrated Graphene Complementary Inverters under Ambient Conditions

The fundamental building blocks of digital electronics are logic gates which must be capable of cascading such that more complex logic functions can be realized. Here we demonstrate integrated graphene complementary inverters which operate with the same input and output voltage logic levels, thus allowing cascading. We obtain signal matching under ambient conditions with inverters fabricated from wafer-scale graphene grown by chemical vapor deposition (CVD). Monolayer graphene was incorporated in self-aligned field-effect transistors in which the top gate overlaps with the source and drain contacts. This results in full-channel gating and leads to the highest low-frequency voltage gain reported so far in top-gated CVD graphene devices operating in air ambient, A(v) ～ -5. Such gain enabled logic inverters with the same voltage swing of 0.56 V at their input and output. Graphene inverters could find their way in realistic applications where high-speed operation is desired but power dissipation is not a concern, similar to emitter-coupled logic.     

Recapitulating Antioxidant and Antibacterial Compounds into a Package for Tissue Regeneration: Dual Function Materials with Synergistic Effect

Oxidative damage and infection can prevent or delay tissue repair. Moreover, infection reinforces reactive oxygen species (ROS) formation, which makes the wound's condition even worse. Therefore, the need for antioxidant and antibacterial agents is felt for tissue regeneration. There are emerging up-and-coming biomaterials that recapitulate both properties into a package, offering an effective solution to turn the wound back into a healing state. In this article, the principles of antioxidant and antibacterial activity are summarized. The review starts with biological aspects, getting the readers to familiarize themselves with tissue barriers against infection. This is followed by the chemistry and mechanism of action of antioxidant and antibacterial materials (dual function). Eventually, the outlook and challenges are underlined to provide where the dual-function biomaterials are and where they are going in the future. It is expected that the present article inspires the designing of dual-function biomaterials to more advanced levels by providing the fundamentals and comparative points of view and paving the clinical way for these materials.     

The Minimum Vulnerability Problem

We revisit the problem of finding \(k\) paths with a minimum number of shared edges between two vertices of a graph. An edge is called shared if it is used in more than one of the \(k\) paths. We provide a \({\lfloor {k/2}\rfloor }\) -approximation algorithm for this problem, improving the best previous approximation factor of \(k-1\) . We also provide the first approximation algorithm for the problem with a sublinear approximation factor of \(O(n^{3/4})\) , where \(n\) is the number of vertices in the input graph. For sparse graphs, such as bounded-degree and planar graphs, we show that the approximation factor of our algorithm can be improved to \(O(\sqrt{n})\) . While the problem is NP-hard, and even hard to approximate to within an \(O(\log n)\) factor, we show that the problem is polynomially solvable when \(k\) is a constant. This settles an open problem posed by Omran et al. regarding the complexity of the problem for small values of \(k\) . We present most of our results in a more general form where each edge of the graph has a sharing cost and a sharing capacity, and there is a vulnerability parameter \(r\) that determines the number of times an edge can be used among different paths before it is counted as a shared/vulnerable edge.     

Significance of Conical and Polyhedral Domes in Persia and Surrounding Areas: Morphology, Typologies and Geometric Characteristics

The aim of this paper is to identify the unique features of the conical and polyhedral domes which topped a majority of distinct tomb towers during the early Islamic era. As opposed to previous general historic studies, this paper introduces a new analytical approach which allows the complete comprehension of the formal architectural language of conical and polyhedral domes based on an epistemological premise of their space syntax. Through an analytic review of selected examples, the paper suggests and addresses the origin of conical domes, their formal morphological compositions and typological forms based on the number of their external shells from the Seljuk era throughout the Timurid period in Iran and nearby regions. The theoretical framework for the formal language of conical and polyhedral domes sheds new light on undiscovered information about the essential characteristics of Persian domes in this region.