Tree Search Fuzzy NARX Neural Network Fault Detection Technique for PV Systems with IoT Support

The photovoltaic (PV) panel’s output energy depends on many factors. As they are becoming the leading alternative energy source, it is essential to get the best out of them. Although the main factor for maximizing energy production is proportional to the amount of solar radiation reaching the photovoltaic panel surface, other factors, such as temperature and shading, influence them negatively. Moreover, being installed in a dynamic and frequently harsh environment causes a set of reasons for faults, defects, and irregular operations. Any irregular operation should be recognized and classified into faults that need attention and, therefore, maintenance or as being a regular operation due to changes in some surrounding factors, such as temperature or solar radiation. Besides, in case of faults, it would be helpful to identify the source and the cause of the problem. Hence, this study presented a novel methodology that modeled a PV system in a tree-like hierarchy, which allowed the use of a fuzzy nonlinear autoregressive network with exogenous inputs (NARX) to detect and classify faults in a PV system with customizable granularity. Moreover, the used methodology enabled the identification of the exact source of fault(s) in a fully automated way. The study was done on a string of eight PV panels; however, the paper discussed using the algorithm on a more extensive PV system. The used fuzzy NARX algorithm in this study was able to classify the faults that appeared in up to five out of the eight PV panels and to identify the faulty PV panels with high accuracy. The used hardware could be controlled and monitored through a Wi-Fi connection, which added support for Internet of Things applications.

Human Design Parameters for Safety of Products and Systems

Designers spend much efforts in defining their products and systems, planning how they work during normal operation. Design assisting tools like Design Matrices in Axiomatic Design (AD) or Design Record Graphs (DRG) are available to the designer in search for ways to improve their work. Majority of accidents, however, take place during irregular operations like maintenance when interlocks are often bypassed and automatic processing are switched to manual. System safety is then in the hands of human operators. A number of past AD studies have addressed safety in products and systems, however, design parameters (DPs) have been physical parts or structures. This paper shows assignment of human actions, like, “reading the quantity display,” “making judgement,” or “pressing a control button,” as DPs in axiomatic design. Such human DPs play important roles during maintenance, nevertheless, designers often leave out safety evaluation of their designs in this maintenance mode. When a human DP fails to meet its functional requirement (FR), the product often faces failure and the system often heads into an accident. Identifying human DPs in products or systems thus alerts maintenance phase workers about actions that are critical for safety. Most accidents take place with excessive dependence on human DP of memory.

RELATIONSHIPS BETWEEN REGULAR AND IRREGULAR COLLECTIVE COMMUNICATION OPERATIONS ON CLUSTERED MULTIPROCESSORS

We characterize collective communication operations on (clustered) multiprocessor systems in terms of their communication volume, and arrive at useful relationships between regular and irregular operations over sets of processors and sets of cluster-nodes, respectively. We show that regular problems over sets of processors induce corresponding irregular problems over sets of nodes. We hereby identify a symmetric variant of the personalized all-to-all communication problem that might be worth studying in its own right, and discuss an algorithm for solving this problem. From a simple algorithm for the regular all-gather problem over sets of processors, we derive an algorithm for the irregular all-gather problem over both sets of processors and sets of nodes. For communication libraries like MPI, the relationships emphasize the need for efficient algorithms for the irregular collective communication operations.