•A data-driven approach is proposed by using smart gate data.•Relationship between truck arrivals and total turnaround time is revealed.•Quotas in each time window of TAS is optimized by a robust ...optimization model.•Container trucks’ turnaround time in ports are effectively reduced.
A longer turnaround time of container trucks in ports are commonly related to a higher energy cost and more carbon emissions, hindering the green development goal of ports. In this context, the implementation of Truck appointment system (TAS) is widely recognized as a very effective way to reduce external container trucks’ total turnaround time in ports. However, the number of appointment quotas allocated for each time window are the key to determine the efficiency of a TAS. This study proposed a data-driven approach to address the appointment quota optimization problem, which combined data mining technologies with mathematical optimization modeling methods, and an empirical study in YT port, China was given. Specifically, the smart gate data of the port were mined to explore the causal relationship between the number of truck arrivals at each time window and their total turnaround time within the port. The results exhibited a non-deterministic quadratic function relationship, and the range of changes regarding total turnaround time were measured by boundary functions obtained through a stepwise approaching algorithm. Considering the obtained causal relationship and its uncertainties, a robust optimization model was built to find the optimal appointment quota plan by minimizing the total turnaround time of external container trucks and the total deviations from the trucks’ preferred arrival time in the worst case. A numerical experiment was designed to examine the validity of the proposed data-driven approach, and compare the effectiveness of the proposed approach with a conventional stochastic optimization method. The results indicated the proposed approach was more effective on reducing the external container trucks’ total turnaround time in ports under a Truck appointment system.
Wide-bandgap devices, such as silicon carbide and gallium nitride, have high switching speed potential. However, the actual speed in practical application is limited by circuit parasitics and ...interaction between high-side switch and lowside switch in a phase-leg configuration, known as crosstalk effect. This article proposes an isolated voltage source gate driver with crosstalk suppression capability to take full advantage of the inherent high switching speed ability of silicon-carbide devices. By applying variable gate voltage through the auxiliary circuit, the crosstalk problem can be mitigated. Using the original gate-source voltage as auxiliary circuit driving signal, the gate driver does not introduce any extra control signals, which avoids additional signal/power isolations and makes the auxiliary circuit very convenient to be implemented on the existing commercial gate driver. The auxiliary circuit makes the gate voltage rise from 0 V other than -5 V when the switch turns on, leading to faster switching speed and lower switching loss compared with a traditional gate driver. LTSPICE simulation and double pulse test experiment based on 1.2-kV/60-A silicon-carbide MOSFETs are conducted to evaluate the crosstalk suppression capability of the proposed gate driver.
The I-READ 4.0 project is aimed at developing an integrated and autonomous Cyber-Physical System for automatic management of very large warehouses with a high-stock rotation index. Thanks to a ...network of Radio Frequency Identification (RFID) readers operating in the Ultra-High-Frequency (UHF) band, both fixed and mobile, it is possible to implement an efficient management of assets and forklifts operating in an indoor scenario. A key component to accomplish this goal is the UHF-RFID Smart Gate, which consists of a checkpoint infrastructure based on RFID technology to identify forklifts and their direction of transit. This paper presents the implementation of a UHF-RFID Smart Gate with a single reader antenna with asymmetrical deployment, thus allowing the correct action classification with reduced infrastructure complexity and cost. The action classification method exploits the signal phase backscattered by RFID tags placed on the forklifts. The performance and the method capabilities are demonstrated through an on-site demonstrator in a real warehouse.
Silicon Carbide (SiC) power transistors are more and more used in electric energy conversion systems. SiC power semiconductors devices, such as SiC metal-oxide-semiconductor field-effect transistor ( ...mosfet ) can operate at higher frequency and higher temperature compared to Silicon power mosfet or insulated-gate bipolar transistor. However, the maturity of the SiC technology is moderate compared to the well-known Silicon-based power semiconductor devices. Recent research works on reliability of SiC power mosfet identified gate leakage currents as an ageing indicator. The monitoring of ageing indicators during normal operation may definitely help to predict damages and simplify the maintenance on the energy conversion systems. Due to the low amplitude of gate leakage currents, its direct measurement is difficult even under laboratory conditions and requires an offline characterization. This article presents a new method for estimating the gate leakage current using the gate drive circuit. The proposed method takes advantage of the internal structure of the typical gate drivers used to command SiC power mosfet s.
SiC MOSFET has superior switching performance over Si IGBT in terms of power loss and temperature characteristics. In order to significantly improve the efficiency and power density of medium-voltage ...drive and high-power converters, this article proposes a current-source gate driver (CS-GD) for series-connected SiC MOSFETs, forming a universal block of series-connected SiC devices with the higher voltage rating. The proposed CS-GD has better gate voltage synchronization performance because of its constant gate current and novel gate driver structure. By implementing synchronized gate voltages, the snubber circuit is designed only for power loop difference and gate displacement current difference, and the snubber can be minimized or even be eliminated. The proposed block has been verified by LTSPICE simulations and multipulse test experiments under 200-kHz, 2-kV, 0~60-A condition using three 1.2-kV/60-A C2M0040120D SiC MOSFETs connected in series.
Smart Cart With Multi-shopping Solutions Faisal, Tarig; Awawdeh, Moath; Habte, Daniel ...
International journal of interactive mobile technologies,
12/2021, Letnik:
15, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Consumerism has constantly been growing, and visiting marketplaces and purchasing is a key development factor for the economic development of a city. The spending habits of people are a reflector of ...many development indices. As people go out for purchasing in malls for shopping essential items, they often tend to find long queues at the billing counter, and the queues are more longer during weekends and during sale seasons. This has been deterring people from going out shopping and instead resort to online shopping. This has affected the sales and revenue of departmental chains. Also, people spend quite a considerable amount of time searching through rows in order to find the items of their choice. Proposing a solution to these above-mentioned problems using technology is a real boon. Installing a payment option on the cart itself would result in cutting down the waiting times in queues. Moreover, the customers can also benefit from navigation through the virtual maps that would be displayed on the screens of the carts. This reduces the time wasted by customers in searching for products. Hence the customers are self-dependent during their shopping. For the retail group, their transactions and management are truly simplified with these developments. Additionally, the counter labor will decrease if not cease to zero, which in turn reduces the labor cost drastically. In times of pandemic like now, people have been sticking with online shopping due to various reasons, but they long to go out and spend time in the malls as they would in normal times. The proposed solution would definitely assist in the normalization of lives and bring back on-ground retail back to life.
Inland navigation infrastructure like locks and dams form a vital part of the global economy. Locks facilitate the transport of hundreds of millions of dollars’ worth of goods on a daily basis. A ...primary cause for downtime of locks in the United States is damage to lock gates. Current inspection methods involve the complete closure of locks to visually inspect for damage. A common target of such inspections is the identification of “gaps” that form along the bearing surface boundary of miter gates. These gaps accelerate the fatigue failure of the gate by disrupting the designed load distribution mechanism. This article presents a novel engineering application of structural health monitoring for full-scale civil infrastructure with a method to automatically quantify the damage quantity of interest, that is, the gaps using measured strain data. We propose a framework for damage estimation of full-scale civil infrastructure in general and miter gates in particular, leveraging recent advances in deep Bayesian learning. A new two-term loss function is produced to increase the accuracy of the trained networks and the model uncertainties are conveyed using Monte Carlo dropout. In addition, we propose a strategy to model bearing surface gaps using non-linear contact analyses and use the proposed model to determine the sensitivity of measured strains to damage. The proposed framework is implemented for the miter gates at the Greenup locks and dam. Finally, the proposed methodology is validated using measured data. Slopes measured from the lock gate are used as the input to the trained networks to estimate the gap depths. The finite element model is updated using the estimated gap depths. The predicted slopes and strains from the updated model are shown to match the measured strains and slopes well. The results demonstrate the efficacy of the approach for damage detection in full-scale civil infrastructure.
Recent Modular Multilevel Converter (MMC) topology allows for drastic improvements in power electronic conversion such as higher energy quality, lower power semiconductors electrical stress, ...decreased Electro-Magnetic Interferences (EMI), and reduced switching losses. MMC is widely used in High Voltage Direct-Current (HVDC) transmissions as it offers, theoretically, no voltage limit. However, its control electronic structure is not modular itself. Especially, the insulation voltage between the submodule gate drivers’ primaries and secondaries depends on the number of submodules. The converter voltage levels cannot be increased without designing all gate driver isolations again. To solve that issue, the novel concept of distributed galvanic insulation is introduced for multilevel converters. The submodule’s gate drivers are daisy-chained, which naturally reduces the insulation voltage to the submodule capacitor voltage, regardless of the number of submodules. The MMC becomes truly modular as the number of submodules can be increased without impacting on the previous control electronic circuit. Such an innovative control structure weakens the link between the main control unit and the gate drivers. This inherent structural problem can be solved through the use of Smart-Gate Drivers (SGD), as they are often equipped with fast and bidirectional communication channels, while highly increasing the converter reliability. The innovation proposed in that work is the involvement of smart gate drivers in the distributed galvanic insulation-based MMC control and monitoring. First, the numerous benefits of smart gate drivers are discussed. Then, an innovative Voltage Balancing Algorithm directly integrated on the chained gate drivers is proposed and detailed. It features a tunable parameter, offering a trade-off between accurate voltage balancing and execution time. The proposed embedded algorithm features a low execution time due to simultaneous voltage comparisons. Such an algorithm is executed by the gate drivers themselves, relieving the main control unit in an original decentralized control scheme. A simulation model of a multi-megawatts three-phase grid-tied MMC inverter is realized, allowing validation of the proposed algorithm. Matlab/Simulink logic blocs allow us to simulate a typical CPLD/FPGA component, often embedded on smart gate drivers. The converter with the proposed embedded algorithm is simulated in steady-state and during load impact. The controlled delay and slew rate inferred by the algorithm do not disturb the converter behavior, allowing its conceptual validation.
This reprint is a reprint of the articles that appeared in Sensors' (MDPI) Special Issue on “Sensors and Systems for Indoor Positioning". The published original contributions focused on systems and ...technologies to enable indoor applications.
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