36 research outputs found
Single Tree Vegetation Depth Estimation Tool for Satellite Services Link Design
Attenuation caused by tree shadowing is an important factor for describing the propagation channel of satellite services. Thus, vegetation effects should be determined by experimental studies or empirical formulations. In this study, tree types in the Black Sea Region of Turkey are classified based on their geometrical shapes into four groups such as conic, ellipsoid, spherical and hemispherical. The variations of the vegetation depth according to different tree shapes are calculated with ray tracing method. It is showed that different geometrical shapes have different vegetation depths even if they have same foliage volume for different elevation angles. The proposed method is validated with the related literature in terms of average single tree attenuation. On the other hand, due to decrease system requirements (speed, memory usage etc.) of ray tracing method, an artificial neural network is proposed as an alternative. A graphical user interface is created for the above processes in MATLAB environment named vegetation depth estimation tool (VdET)
A Multi-Method Behavior Setting Analysis of a Protracted Refugee Camp in Jordan
The study draws upon theory and research on behavior settings to understand how the built environment shapes selected aspects of behavior in a protracted refugee camp located in an urban area in Jordan. Over 3 years, the research used a multi-method analysis of behavior settings within a residential space and an assessment of modifications to the home using a pre-post research design. The findings showed that the settings can carry new meanings although the occupants greatly restrict their behaviors to conform to the settings they occupy. The findings also indicated the importance of the psychological dimension, which was undervalued in previous applications of the theory. The methodology used demonstrated that localized problems can be addressed by analyzing the features of the relevant behavior setting to reveal the underlying source of the problem. This will help identify solutions that promote behavioral changes to ameliorate displacement and improve the built environment
Modeling and Link Performance Analysis of Busbar Distribution Systems for Narrowband PLC
Busbar distribution system is used as a modular infrastructure to carry electrical energy in low voltage grid. Due to the widespread usage in industrial areas, the power line communication possibilities should be investigated in terms of smart grid concept. This paper addresses modeling of the busbar distribution system as a transmission line and gives some suggestions on the link performance for narrowband power line communication for the first time in literature. Firstly, S-parameters of different current level busbars were measured up to 500 kHz for all possible two-port signal paths. The utilization of the frequency-dependent model was proposed to extract transmission line characteristics to eliminate the unwanted measurement effects. Particle swarm algorithm was used to optimize the model parameters with a good agreement between measured and simulated S-parameters. Additionally, link performance of busbar distribution system as a power line communication channel at 3 kHz-148.5 kHz band was examined for frequency shift keying and phase shift keying modulations under different network configurations such as varying busbar type, the line length between transmitter and receiver, branch number, and terminating load impedance. Obtained results were presented as bit-error-rate vs. signal to noise ratio graphs
Analysis of Channel Transfer Functions in Power Line Communication System for Smart Metering and Home Area Network
The paper deals with simulations of power line channel transfer functions in Network Simulator version 3. Firstly,
an empirical model and calculation of the channel transfer function are given to reflect the necessity of channel
transfer function for Power Line Communication system design. The framework for Power Line Communication in Network
Simulator version 3 and then the necessary extension implementation are introduced. Other simulators are also mentioned.
Secondly, various scenarios were implemented for the analysis and simulation of power line channel transfer functions.
New scenarios for large topologies and for different approaches to calculate primary parameters were created.
In the simulations, various kinds of topologies are considered for an analysis of the power line transfer function.
The simulation part also focuses on the simulation of channel transfer function where the time- and frequency-selective
impedances are considered. Finally, the last part focuses on measurements and a comparison of the simulation results
with real measurements are given
Performance testing and methodology for evaluation of power line communication
The paper describes a unified methodology which takes into account the advantages and disadvantages of different Power Line Communication (PLC) technologies suitable for Smart Metering deployment. The methodology should provide a detailed evaluation of PLC technologies based on a clear definition of the different parameters and their measurement. Based on this methodology, we should be able to provide a comparison of the selected technologies and the methodology should also provide data for the design of a telecommunication infrastructure for Smart Metering/Smart Grids. In this paper and based on this methodology, we also present the performance tests carried out in laboratory environment on low voltage and in on-field conditions on medium voltage. © 2018 Kauno Technologijos Universitetas. All rights reserved
Performance testing and methodology for evaluation of power line communication
The paper describes a unified methodology which takes into account the advantages and disadvantages of different Power Line Communication (PLC) technologies suitable for Smart Metering deployment. The methodology should provide a detailed evaluation of PLC technologies based on a clear definition of the different parameters and their measurement. Based on this methodology, we should be able to provide a comparison of the selected technologies and the methodology should also provide data for the design of a telecommunication infrastructure for Smart Metering/Smart Grids. In this paper and based on this methodology, we also present the performance tests carried out in laboratory environment on low voltage and in on-field conditions on medium voltage. © 2018 Kauno Technologijos Universitetas. All rights reserved
PCL and PCL-based materials in biomedical applications
Biodegradable polymers have met with an increasing demand in medical usage over the last decades. One of such polymers is poly(epsilon-caprolactone) (PCL), which is a polyester that has been widely used in tissue engineering field for its availability, relatively inexpensive price and suitability for modification. Its chemical and biological properties, physicochemical state, degradability and mechanical strength can be adjusted, and therefore, it can be used under harsh mechanical, physical and chemical conditions without significant loss of its properties. Degradation time of PCL is quite long, thus it is used mainly in the replacement of hard tissues in the body where healing also takes an extended period of time. It is also used at load-bearing tissues of the body by enhancing its stiffness. However, due to its tailorability, use of PCL is not restricted to one type of tissue and it can be extended to engineering of soft tissues by decreasing its molecular weight and degradation time. This review outlines the basic properties of PCL, its composites, blends and copolymers. We report on various techniques for the production of different forms, and provide examples of medical applications such as tissue engineering and drug delivery systems covering the studies performed in the last decades