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This paper proposes a method of embedding AR (augmented reality) markers in a high-speed video sequence so that they are imperceptible to human eyes. The embedded markers appear for very short periods and keep changing their positions at lightning speed. By carefully designing the timings of marker display, a camera with a sufficiently short exposure time running at any frame rate is able to detect...
Structured lighting is a computer vision technique that projects illumination patterns onto the scene to facilitate feature extraction from the captured images. The use of lowcost cameras is avoided not only due to their low image quality but mostly due to the lack of a synchronization mechanism for the illuminators. In this paper we propose a method to synchronize low-cost cameras and illuminators...
Problems with power quality in the grid have gained a lot of attention recently due to rapid increase in the amount of grid-connected power converters. The converter should produce sinusoidal currents also during abnormal conditions, such as unbalanced grid voltages. Several methods, like the delayed signal cancellation-based method (DSC), have been proposed to alleviate the detrimental effect of...
Electrical energy generation is evolving from centralized towards distributed energy resources (DER) like wind and solar power plants. In such power systems, new challenges arise for the design of voltage source converter (VSC) control strategies. In the last few years synchronverters have gained interest from the research community due to their capability of emulating synchronous machines (SMs) and...
For the control of electric motors, conventional inverters have utilized position and current sensors, but they undesirable in terms of cost and maintenance effort. For this reason, approaches without the sensors are developed by applying back electromotive force or signal injection-based method which also has some problems related to the the deterioration of control performance in low speed range...
In this paper, a new critical-conduction-mode (CRM)-based modulation is proposed for three-phase inverters. With this modulation, soft switching is achieved and the efficiency of the inverter is improved, especially for high frequency operation with SiC MOSFET. In three-phase string PV inverter applications, by operating at switching frequency above 300 kHz, power density of the inverter is estimated...
This paper proposes optimal switching period phase-shifted method for slave inverter to reduce grid current ripples in synchronized two parallel three-phase grid-connected voltage-source inverters (VSI). In parallel operation, a 180 degree phase shifted method generally takes of advantage of reducing grid current ripples in same DC-link voltage for each grid-connected VSI. However, in case of unequal...
A digital communications receiver requires precise symbol synchronization before the transmitted information can be recovered. Gardner's algorithm is a synchronizer that can acquire and track timing with only two samples per symbol, and it does not require prior carrier synchronization. In this paper, a feed-forward, all-digital version of Gardner's algorithm is presented. It is shown that this synchronizer...
Time synchronization over a distributed BLE wireless network poses several challenging problems which may affect the accuracy of time stamping of events recorded by BLE devices. In this paper, we study the accuracy of a time synchronization scheme based on generation of an event in the application program at the time of BLE connection establishment. We discuss the background of the problem, explain...
Dataflow models of computation have early on been acknowledged as an attractive methodology to describe parallel algorithms, hence they have become highly relevant for programming in the current multicore processor era. While several frameworks provide tools to create dataflow descriptions of algorithms, generating parallel code for programmable processors is still sub-optimal due to the scheduling...
In industrial automation, EtherCAT is a real-time communication protocol widely employed in the local computer networks for fast and predictable data communication between system processes. End-to-end delay is a key performance indicator to industrial applications as it reflects the real-time capability of the system. This paper explores end-to-end delays of EtherCAT-based control systems under different...
In industrial applications synchronized sensor nodes are vital for many tasks like multi parameter sampling of complex machinery behavior. The wirelessly connected nodes are usually synchronized to a base station. Therefore, frequency or period estimation of the reference clock is a key issue for all connected tasks like sampling, localization or applying energy optimized communication protocols....
This paper proposes the algorithms for optimization of Remote Core Locking (RCL) synchronization method in multithreaded programs. The algorithm of initialization of RCL-locks and the algorithms for threads affinity optimization are developed. The algorithms consider the structures of hierarchical computer systems and non-uniform memory access (NUMA) to minimize execution time of RCL-programs. The...
In this paper, the main purpose is to design the model of a given mechatronics line, composed by several workstations and serviced during the recovery, transport and return of a work piece by a Wheeled Mobile Robot (WMR) which has mounted a Robotic Manipulator (RM). The work piece to be transported has been initially tested and did not pass the quality test. In this context, the Processing/Reprocessing...
This paper presents three three-phase AC-DC configurations in which two are unidirectional and have reduced switch count. The investigated topologies have one DC-link and are composed by two converters in series connection through transformers, that process part of the total power, while the conventional converters have two DC-links and a transformer processing all the power. The replacement of switches...
Process-aware Information Systems (PAIS) have become ubiquitous in companies. Thus the amount of data that can be used to analyze and monitor process executions is vast. The event logs generated by PAIS might contain information about decision making processes and can support the understanding and improving of procedures in companies. Mining decisions and constraints from logs has already been investigated,...
For a grid-connected Voltage-Source Converter (VSC), dynamics of the grid synchronization plays an important role in affecting the converter performances and stability. Due to its significance, this paper gives a comparative analysis about some basic grid synchronization schemes, through viewpoint of dynamic performances, which appeared as the impacts of voltage perturbation on the estimated angle...
Four unidirectional AC-DC-AC three-level and two-level three-leg converters are proposed in this paper. This converters are composed of an unidirectional rectifier and a bidirectional inverter, using three-level and two-level legs and an unidirectional NPC leg at rectifier side. When compared with the two-level leg, the three-level leg presents voltage stress reduction on switches for the same DC-link...
Due to its modularity and scalability, modular multilevel converter is a promising topology for medium voltage applications, such as energy storage or motor drives. Because of the large number of modules, the wiring can become complex if the conventional star topology communication network is used. To solve this issue, a communication link that uses a ring topology to connect the central controller...
Frequency and voltage regulation are required to support the grid under different scenarios. In order to handle these scenarios, classical control strategies demand complex systems to fulfill these requirements. However, synchronous controllers are trending strategies to contribute with frequency and voltage regulation functionalities without the requirement of external elements. Among these strategies,...
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