Differential conductance is a key to characterizing a solid-state device. Estimation of differential conductance from current-voltage characteristic curve amounts to estimate the first order derivative from a discrete set of current-voltage measurements of the device under test. Conventional difference method in estimating derivative is inadequate when data contain noise. A robust method of estimating the first order derivative from a discrete set of evenly distributed current versus voltage measurements is designed where the method does not pose any constraints or limits on the data interval. The proposed method is formalized in the premise of the fundamental theorem of calculus and the inverse problem. The robustness of estimation is ensured using a regularization technique where the regularization operator is considered as a first order differential operator. A modified form of the L-curve technique is used to determine an optimal regularization parameter. The method is tested on synthetic and measured current-voltage characteristics of Schottky diode and MOSFET.

In this paper, a new flexible backhaul design is proposed based on the time-frequency resource grid. The advantage of proposed approach is in the fine granularity bandwidth allocation. Proposed approach allows tunneling of Cloud-RAN modulated radio signals between baseband processing unit and remote radio head within the same resource blocks. In addition, new handover machanism has been introduced to reduce the handover overhead in the backhaul network. The main idea of the proposed handover mechanism is in multicast data transmission to both involved eNodeBs by joint assignment of the resource elements for multiple cells during handover that allows to decrease the amount of backhaul traffic over X2 interface by 20%.

Rapidly increasing traffic demands set up much higher requirements for data rates in the upcoming 5G mobile networks. The most promising approach for capacity enhancement is optimal reuse of network resources by deploying a large number of small cells. In order to maintain the efficiency and performance of new heterogeneous infrastructure, new approached are required to ensure optimal traffic transmission with high capacity. In this paper, we systematize mathematical methods for SDN-controller optimization. The paper contains all main computational methods ensuring the smooth operation of network applying SDN technology. Proposed approach allows to increase the efficiency of network resources utilization, provide the fault-tolerance of infrastructure and high bandwidth of the transport network.

This radio frequency (RF) energy harvesting is an emerging technology and research area that promises to produce energy to run low-power wireless devices. The great interest that has recently been paid to RF harvesting is predominantly driven by the great progress in both wireless communication systems and broadcasting technologies that have availed a lot of freely propagating ambient RF energy. The principle aim of an RF energy harvesting system is to convert the received ambient RF energy into usable DC power. This paper presents a state of the art concise review of RF energy harvesting sources for low power applications, and also discusses open research questions and future research directions on ambient RF energy harvesting.

This paper deals with one of the challenges of cyber-physical systems, namely modelling them as hybrid systems. Specifically the paper aims to utilize hybrid systems framework onto the lift system which comes from the real laboratory lift. The mathematical model was derived using hybrid automata framework in synergy with linear temporal logic. Hybrid automata framework was used to describe continuous dynamics as well as discrete dynamics of the lift system mathematical model. Linear temporal logic was used to formally define rules according to which the lift system is constrained. The whole logic, system dynamics and constrains are then implemented within MATLAB/Simulink environment using Stateflow toolbox. Finally, the verification of the lift mathematical model is performed within chosen scenarios.

This paper describes our effort on the usage of modern information and communication technologies as well as innovation process in the field of teaching. Our goal is to design and develop a web-based system to support management and analysis of course questionnaires for students. The proposed system is broadly divided into two parts. First, we describe the system architecture followed by a preparation of a suitable network environment and a design of a database model used for storage of data about the questionnaires. Second, we present a design of the proposed website, its structure, and finally a proper layout of the questionnaires. An important functionality of our system is also to provide various statistical information obtained from the responses. This enables teachers to exercise introspection and self-reflection in order to improve quality of their teaching of the course. The main goal of our long-term effort is a deployment of the system into use within the course on Type theory, which allows students to grow their knowledge in the principles of type systems and languages of functional programming paradigm.

The design of electrical motors is founded on an inventive idea which creates basic motor structure. Then optimization of dimensions and other parameters follows. Finally, a control or switching strategy can be optimized. This article describes a measurement of an objective function for BLDC motor control optimization. Namely measurement of no load speed and current, efficiency estimation, and noise as a function of the current commutation angle is described. The commutation angle is usually derived from Hall sensors, and its correct value is important for high efficiency and other motor characteristics. Experimental measurements show how speed, current, efficiency, and noise spectrum depends on commutation angle. Presented measurements are primarily intended for in situ optimization of commutation angle on running motor.

Direct torque control (DTC) of induction motor (IM) is important in many applications. In this paper presents a three-level direct torque control is applied for IM using fuzzy-PI controller and hysteresis regulators based on artificial intelligence techniques. The DTC system is known to offer fast decoupled control between torque and flux via a simple control structure. Nevertheless, DTC system has two major drawbacks, with are the variable inverter switching frequency and high torque output ripple. The validity of the proposed control scheme is verified by simulation tests. The stator flux, torque, and current are determined and compared to the above technique.

This work deals with the solar cells with orientation on the calculation of operating temperature of the polycrystalline solar cell, which is under actual load. Operating conditions have a significant effect on the efficiency of solar cells. In the summer with increasing temperature, the efficiency decreases. In the winter, efficiency and output voltage are rising. The operating temperature is determined by intensity of solar radiation, the types of materials used by construction and operating condition. The aim of this work was simplify of the calculation of operating temperature of solar cells. The result of this work is a derived equation that allows a more accurate and faster calculation this temperature with using Matlab software.

In this article, space vector based decoupled PWM techniques are proposed for both symmetrical and asymmetrical configuration of open-end winding induction motor drive. These decoupled PWM techniques are generated using instantaneous reference voltages of the two inverters. That means, one inverter reference voltages are phase shifted with respect to other inverter reference phase voltages, So that each inverter operates independently. It does not require any complex computations as in case of conventional PWM techniques. A common-mode voltage is identified in the dual inverter configuration. These decoupled PWM techniques also reduce the common mode voltage by better extent. All the proposed PWM techniques for symmetrical and asymmetrical configurations of open-end winding induction motor are implemented using MATLAB/SIMULINK and the corresponding results are reported and compared.