A Microstrip Low-Pass Filter Design Using a Modified Radial Resonator in the Application of Aircraft Distance Measurement Equipment

In this paper, the application of microstrip technology is investigated in low-pass filters. A cascade microstrip low-pass filter with a sharp frequency response and a good cut-off bandwidth is presented using a modified radial resonator. The advantages of this proposed filter include minor losses in the transit band as well as the desired return. This filter design shows consistency when compared with the results of simulation and model performance. A comparison between the parameter values of this filter and previous structures indicates that it is desirable. The proposed filter can be used in modern communication systems such as aircraft distance measurement equipment (DME) antenna.

Design of a Pitch Controller for a Wind Turbine Using Hybrid Mean-Variance Mapping Optimization

A variable-speed wind energy conversion system (WECS) has the advantage of extracting more power from the time-varying wind. To achieve this, the pitch angle is controlled to maintain the speed of the turbine and hence the generated power at a constant level, while reducing mechanical stress on the turbines. In this work, a proportional-integral (PI) controller is used for pitch angle control. The optimal PI control gains and are tuned by the hybrid mean-variance mapping optimization (MVMO-SH) technique, particle swarm optimization (PSO), and a genetic algorithm (GA). Different fitness evaluation criteria and optimization techniques are compared, and the performances of optimal controllers presented in the time domain. The results reveal that MVMO-SH achieves the minimum error criteria within a shorter time. The optimal controller design gives an error of less than in the region for which it is tuned. The performance of the optimal PI controller is designed for one operating condition in different cases of wind gust, random variation of wind, and disturbance from the grid side to mitigate line to ground fault. The performance of the controller is shown to be satisfactory in all the cases studied.

The Design of Cognitive Training Games for the Thai Elderly

Cognitive aging is one of the main public health concerns, often involving a decline in memory and decision-making abilities as people age. Cognitive training games have been widely used to improve working memory as well as enhancing short and long-term memory. In this study, we aim to develop a cognitive training game based on the Thai environment and speech recognition technology. The designed cognitive training tasks were evaluated by performing electroencephalography (EEG) on six elderly volunteers, who passed the Thai mental state examination. The participants were instructed to memorize a series of pictures and calculate simple math questions. The EEG signals of the participants were recorded during training. The participants engaged in four cognitive training tasks over three trials. An increase in training scores was found to be related to a rise in three EEG power spectrum bands: theta, alpha, and beta. Participants expressed the highest average level of satisfaction towards the easiest tasks in the four cognitive training games. This implies that when performing an easy task, an increase in the power spectral density of three EEG bands tends to occur. As a result, the proposed cognitive training game could leverage the working memory of the Thai elderly. The game design can be enhanced by integrating human-based interactive tasks, such as handwriting and eye movements. Its replication on a larger scale should be assessed in the future.

Management of a Solar-PV System with Energy Storage

A solar-PV system is generally connected to distributed generation (DG) by the utility grid. The solar inverter retains some capacity after active power generation. Reactive power compensation can be achieved by utilizing the remaining capacity of the solar-PV inverter. This paper introduces an energy management system (EMS) for real and reactive power management. The proposed EMS includes two modes: PV-STATCOM and islanding. In PV-STATCOM mode, the PI control is used whereas for the islanding mode, voltage frequency control is employed. This paper proposes the energy management of reactive power by utilizing the solar photovoltaic (PV) inverter as a static synchronous compensator (PV-STATCOM). Therefore, no other additional flexible AC transmission system controllers or series/shunt capacitors are required. During the islanding mode, the storage provides continuous supply to the load. The system is simulated using single-phase and three-phase modes with the hardware results also revealed. The proposed scheme provides a significant improvement in power factor while reducing the total harmonic distortion.

Virtual Inertia Design Procedure for Energy Storage Systems to Increase Frequency Response Performance in Microgrids

The frequency instability caused by low system inertia is a common problem for small power systems such as microgrids since it can lead to stepping load shedding and generation tripping when disturbances occur. To alleviate the problem, this paper proposes a procedure for the virtual inertia design of an energy storage system (ESS) using the linear quadratic regulator (LQR) technique. The advantage of this proposed procedure is that it can separately manipulate the frequency response performance indices: the nadir and rate of change of frequency (RoCoF). The results confirm that the proposed procedure enables the microgrid to maintain frequency stability and avoid unnecessary load shedding whether operating in the grid-connected or islanding mode.

Recent Trends in Power Quality Improvement: Review of the Unified Power Quality Conditioner

The electrical power sector is currently focusing on power quality (PQ) issues and their mitigation. Industrial automation and the use of power electronic converters for the integration of distributed generation create various PQ problems. This necessitates PQ enhancement, which in turn helps to improve the life span of the equipment as well as the reliability of supply for feeding critical loads within the system. This paper presents a comprehensive review of the Unified Power Quality Conditioner (UPQC) and its widespread application in the distribution system. The UPQC belongs to the family of active power filters. It contributes to the alleviation of voltage and current-related PQ issues along with power factor correction and the integration of renewable energy systems in the distribution network. This paper discusses various topologies, compensation methods, control theories, and the technological developments in recent years. More than 160 research papers have summarized the features of UPQC for further applications. Based on the outcomes of the investigation, the future direction of the UPQC is discussed. This paper is expected to play a major role in guiding research scholars in the application of the UPQC.

Lyapunov Analysis of Two Imbalanced Power System Areas

The transient stability is the capability of the system to preserve synchronism while being affected by large disturbances. It is a nonlinear problem that requires a simultaneous solution for many differential equations. Therefore, a thorough analysis is needed to resolve it. In this paper, we present the transient stability for multimachine under different fault cases and to analyze using the Lyapunov function. It serves as an analytical tool to determine the necessary condition to be stable. The system is stable as long as it is contained in the region of attraction. Meanwhile, the swing equation and reduced admittance matrix are used to model the system in three conditions, pre-fault, during the fault, and post-fault. The numerical simulations are conducted to verify that the synchronism can be preserved despite under faults on the transmission lines by achieving the critical clearing time.

A Novel Secret Location Sharing Scheme for Wireless Sensor Network

The wireless sensor network is a collection of sensor nodes that operate collectively to gather sensitive data from a target area. In the process of data collection the location of sensor nodes from where data is originated matters for taking any decision at the base station. Location i.e. the coordinates of a sensor node need to be shared among other nodes in many circumstances such as in key distribution phase, during routing of packets and many more. Secrecy of the location of every sensor node is important in any such cases. Therefore, there must be a location sharing scheme that facilitates the sharing of location among sensor nodes securely. In this paper, we have proposed a novel secure and robust mechanism for location sharing scheme using 2-threshold secret sharing scheme. The implementation process of the proposed model is shown here along with results and analysis.

Layer 2 Path Evaluation System using Machine Learning

Is it strange that the spanning tree protocol (STP) has been the only thing used to defend the Layer-2 backbone against looping? Do we trust it? For several decades, the campus backbone has often been an unsuspected problem, one of which is STP failure. Meanwhile, the MAC address flapping is probably a feasible issue for modern network fabrics. According to the serious Layer-2 issues, particularly the legacy switches extended STP design, this work uses the notion of a software-defined network fashion to evaluate the traditional and modern networks. Through the MAC address lookup of all bridge devices, this work proposes the Layer-2 evaluation system (LES), which uses a novel approach known as support supervised learning to create the data preparation for machine learning. Additionally, the LES enabled network administrators to determine their backbones. This study is intended to evaluate the potential slowdown network caused by MAC address problems. Furthermore, this work investigates the proposed method in a real network, and it also covers the evaluation and performance of our proposed method.

A Modified Exact Reconstruction Algorithm to Determine the Complex Permittivity Perturbations of a Cancer Affected Biological Target using Microwave Tomography Technique

Microwave Tomography Technique (MTT) is an emerging technology that is showing its effectiveness in detecting Cancer at early stage. Due to absolute random and non-deterministic characteristics of Cancer cells, more advancements are required in MTT to accurately detect the presence as well as the location of the affected region. Considering this fundamental issue, in this paper, we have proposed a modified Exact Reconstruction Algorithm (mERA) which is capable enough to provide a detailed analysis of all kinds of complex dielectric perturbations of a cancer affected biological target. In MTT, the detection of presence of a cancerous tumor inside any organ of human body has been done using different image reconstruction algorithms. On the other hand, this algorithm uses a selective data segregation mechanism to generate the perturbed complex cell permittivities of the affected organ tissues. Through this study, it has also been verified that how efficiently our proposed approach can able to detect all types of dielectric variations that may be large (20%), small (5%), positive or may be negative and even in a mixed kind of scenario where affected cells possess the mixture of all types of perturbations simultaneously. As cancerous cell shows peculiar behaviour inside human body and its nature varies from person to person and even in-between different stages (stage 1, stage 2, stage 3, stage 4) of cancer, the algorithm is designed in such a fashion that it can able to detect the presence of tumor considering all such possibilities into account. The results validate its high accuracy and effectiveness in the field of cancer diagnosis.