Channel modeling of multilayer diffusion-based molecular nano communication system

In nanoscale communication, diffusion-based molecular communication (DBMC) in which information is encoded into molecule patterns by a transmitter nanomachine, has emerged as a promising communication system, particularly for biomedical and healthcare applications. Although, numerous studies have been conducted to evaluate and analyze DBMC systems, investigation on DBMC system through a multilayer channel has received less attention. The aims of this research are to mathematically model a closed-form expression of mean molecular concentration over multilayer DBMC channel, to formulate channel characteristics, and to conduct performance evaluation of multilayer DBMC channel. In the mathematical model, the propagation of molecules over an n-layer channel is assumed to follow the Brownian motion and subjected to Fick’s law of diffusion. The partial differential equation (PDE) of the time rate change of molecular concentration is obtained by modeling the n-layer channel as an n-resistor in series and considering the conservation law of molecules. Fourier transform and Laplace transform were used to obtain the solution for the PDE, which represents the mean molecular concentration at a receiver nanomachine. In the formulation, channel characteristics such as impulse response, time delay, attenuation or the maximum peak, delay spread and capacity were analytically obtained from the mean molecular concentration. In this stage, the multilayer channel is considered as a linear and deterministic channel. For the performance evaluation, the air-waterblood plasma medium representing the simplified multilayer diffusion model in the respiratory system was chosen. It was found that both analytical and simulation results of mean molecular concentration using Matlab and N3Sim were in good agreement. In addition, the findings showed that the higher the average diffusion coefficient resulted in a smaller dispersion of channel impulse response, and shortened the channel delay spread as well as time delay. However, the channel attenuation remains unchanged. In the performance evaluation, an increase of 100% in the transmission distance increased the time delay by 300% but decreased the maximum peak of molecular concentration by 87.5%. A high channel capacity can be achieved with wide transmission bandwidth, short transmission distance, and high average transmitted power. These findings can be used as a guide in the development and fabrication of future artificial nanocommunication and nanonetwork systems involving multilayer transmission medium. Implication of this study is that modeling and analyzing of multilayer DBMC channel are important to support biomedical applications as diffusion can occur through a multilayer structure inside the human body

Characterisation and optimisation of hybrid polymer/metal oxide photovoltaic devices

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Hubungan antara tahap kompetensi dengan tahap prestasi kerja di kalangan pentadbir Kolej Universiti Teknologi Tun Hussein Onn (KUiTTHO)

This research is a case research in studying the connection of competency level with the administrator in Kolej University Teknologi Tun Hussein Onn (KUiTTHO). Research was done on 40 respondents which were identified playing an important role in giving the feedback. All the respondents are a public service officer from the management and professional group in KUiTTHO, Batu Pahat, Johor. Results from the research are gathered using the Statistical Package for Social Sciences (SPSS version 13.0) software. Model for the Managers Competency and KUiTTHO Annual Assessment Report Form are the main components in the establishing the research framework. As for the independent variable, competencies are divided into four clusters which is personal management, group management, working management and collaborative management. While the dependent variable which is job performance is divided into three dimensions which are working result, knowledge and ability and personal quality. Throughout the research the result shows that the competency level and job performance level for the KUiTTHO administrator are at the highest level. Based on Pearson correlation analysis, research result shows that the positive relationship exists is at the average level. However, competency levels are still playing a huge role in increasing the level of the administrator job performance in KUiTTHO

Modelling of multilayer biological medium under molecular communication paradigm

© 2017 IEEE. Molecular communication is an emerging paradigm that enables both the biological and synthetic nanomachines to communicate with each other within an aqueous biological environment such as the communication between living cells. Prediction of the number of drug molecules near a target site, e.g., tumor cells, is very important for determining the required drug dosages to increase positive therapeutic outcomes. In this paper, we derive an analytical expression for the received molecular signal in a multilayered biological environment. We also present development of particle-based simulator. We find the analytical results for three-layer biological medium compares well with the simulation results. The effect of the diffusion coefficient and the distance between the transmitter and the receiver (e.g., targeted cells) are also investigated

Multilayer Networks in a Nutshell

Complex systems are characterized by many interacting units that give rise to emergent behavior. A particularly advantageous way to study these systems is through the analysis of the networks that encode the interactions among the system's constituents. During the last two decades, network science has provided many insights in natural, social, biological and technological systems. However, real systems are more often than not interconnected, with many interdependencies that are not properly captured by single layer networks. To account for this source of complexity, a more general framework, in which different networks evolve or interact with each other, is needed. These are known as multilayer networks. Here we provide an overview of the basic methodology used to describe multilayer systems as well as of some representative dynamical processes that take place on top of them. We round off the review with a summary of several applications in diverse fields of science.Comment: 16 pages and 3 figures. Submitted for publicatio

Interface-dominated Growth of a Metastable Novel Alloy Phase

A new \textit{D0$_{23}$} metastable phase of Cu$_3$Au is found to grow at the interfaces of Au/Cu multilayers deposited by magnetron sputtering. The extent of formation of this novel alloy phase depends upon an optimal range of interfacial width primarily governed by the deposition wattage of the dc-magnetron used. Such interfacially confined growth is utilized to grow a $\sim$ 300 nm thick Au/Cu multilayer with thickness of each layer nearly equal to the optimal interfacial width which was obtained from secondary ion mass spectrometry (SIMS) data. This growth technique is observed to enhance the formation of the novel alloy phase to a considerable extent. SIMS depth profile also indicates that the mass fragment corresponding to Cu$_3$Au occupies the whole film while x-ray diffraction (XRD) shows almost all the strong peaks belonging to the \textit{D0$_{23}$} structure. High resolution cross-sectional transmission electron microscopy (HR-XTEM) shows the near perfect growth of the individual layers and also the lattice image of the alloy phase in the interfacial region. Vacuum annealing of the alloy film and XRD studies indicate stabilization of the \textit{D0$_{23}$} phase at $\sim$ 150$^{\circ}$C. The role of interfacial confinement, the interplay between interfacial strain and free energy and the hyperthermal species generated during the sputtering process are discussed.Comment: Accepted in Journal of Materials Researc