In this paper, we develop a model-free approximate dynamic programming method for stochastic systems modeled as Markov decision processes to maximize the probability of satisfying high-level system specifications expr...
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Inspection of both small and large diameter bore pipelines for pipe integrity and defect identification with a single system has previously been impractical;especially using wall-press locomotion methods with low adap...
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Nonmagnetic topological insulators (TIs) are known for their robust metallic surface/edge states that are protected by time-reversal symmetry, making them promising candidates for next-generation spintronic and nanoel...
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Hybrid electric vehicles (HEVs) have been widely used due to their significant impacts in urban driving areas. However, the charge of additional weight of the engine/generator is a huge burden. This paper studies a mo...
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Hybrid electric vehicles (HEVs) have been widely used due to their significant impacts in urban driving areas. However, the charge of additional weight of the engine/generator is a huge burden. This paper studies a modern concept to reduce unnecessary weight using the removable engine- generator set that can be can assembled and disassembled by hands. It can be used according to the requirements of the driver such that additional constructions of charging stations are no longer needed. Moreover, charging with driving is feasible unlike Electric Vehicles (EVs). A novel hybrid electric vehicle is tested by city driving cycles and a remarkable improvement in the fuel efficiency in comparison to the conventional hybrid electric vehicle, especially plug-in hybrid vehicle could be demonstrated.
The use of fiber reinforced polymer (FRP) has been implemented as an alternative for strengthening and repairing methods. Nowadays, the use of natural material for FRP has been developed in order to minimize the disad...
The use of fiber reinforced polymer (FRP) has been implemented as an alternative for strengthening and repairing methods. Nowadays, the use of natural material for FRP has been developed in order to minimize the disadvantage effects to nature due to synthetic FRP material and economic reason. In this paper, an experimental study was carried out to evaluate the bond strength of abaca fiber as natural reinforced polymer (NFRP) material in reinforced concrete (RC) beams. The test specimen was a beam that had cross-section area of 100 × 100mm2 and 300mm length. Single rebar was used in this study with 10mm diameter of rebar. Artificial crack was applied in order to consider the initial crack by using cardboard between the concrete. Two externally bonded strengthened beams with a different type of abaca fiber arrangement, bond length, and thickness were applied on the concrete surface. The test was conducted by applying a tension load on the beam until the specimen reach its failure. The results showed that the bond strength decrease as the bond length becomes longer because the maximum load was almost constant for different bond length. The maximum load was approximately around 4 tf for short and long bond length. The compatibility of abaca fiber and rebar was also monitored. Both abaca fiber and rebar able to stand the load compactly. Abaca fiber composite laminate had a similar trend with rebar at the same location where an artificial crack was made. Furthermore, the arrangement and thickness of the abaca fiber composite laminate affected the results.
Tactile sensing has seen a rapid adoption with the advent of vision-based tactile sensors. Vision-based tactile sensors provide high resolution, compact and inexpensive data to perform precise in-hand manipulation and...
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Bitcoin is the leading currency in the cryptocurrency market capturing attention worldwide. Forecasting the Bitcoin price as accurate as possible is essential, but due to its high volatility this task is challenging. ...
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ISBN:
(数字)9781728169262
ISBN:
(纸本)9781728169279
Bitcoin is the leading currency in the cryptocurrency market capturing attention worldwide. Forecasting the Bitcoin price as accurate as possible is essential, but due to its high volatility this task is challenging. Many researchers try, through the years, to develop efficient models for predicting the Bitcoin price using several different data-driven approaches. The objective of this paper is to develop a novel decomposition-ensemble learning model that combines Variational Mode Decomposition (VMD) and Stacking-ensemble learning (STACK) with machine learning algorithms to forecast the Bitcoin price multi-step ahead. The algorithms are k-Nearest Neighbors, Support Vector Regression with Linear kernel, Feed-forward Artificial Neural Network with single-layer perceptron, Generalized Linear Model, and Cubist. Correlation matrix (CORR), principal component analysis (PCA), and Box-Cox transformation (BOXCOX) were used as data preprocessing techniques. Estimating the performance of the proposed models (namely VMD-STACK-CORR, VMD-STACK-PCA, and VMD-STACK-BOXCOX) using relative root mean square error, symmetric mean absolute percentage error, and absolute percentage error measures, defined that for one-day-ahead forecast VMD-STAK-BOXCOX model presented the better performance, and for two and three-days-ahead forecast VMD-STACK-CORR model was chosen, compared to VMD, STACK, and machine learning algorithms models' performance. Diebold-Mariano statistical test was conducted to evaluate a reduction in forecasting errors. Therefore, the proposed models (VMD-STACK-CORR, VMD-STACK-PCA, and VMD-STACK-BOXCOX) indeed forecast accurately Bitcoin price and outperformed the compared models (VMD, STACK, and machine learning models).
Actively controllable microswarms have been a rapidly developing research field with appealing characteristics. Autonomous collision-free navigation of microswarms in confined environments is suitable for various appl...
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Actively controllable microswarms have been a rapidly developing research field with appealing characteristics. Autonomous collision-free navigation of microswarms in confined environments is suitable for various applications, including targeted therapy and delivery. However, several challenges remain unaddressed. First, microswarms possess varying dimensions, and a path planning method suitable to swarms with different dimensions is essential to avoid obstacles. Second, studies on the environment-adaptive navigation of reconfigurable microswarms are limited. Therefore, the planning of the pattern distribution of microswarms based on the local working environment should be examined. This study proposes a deep learning (DL)-based environment-adaptive navigation scheme for swarms. The controller provides reference moving directions for swarms of different sizes in static and dynamic scenarios. Moreover, a pattern-distribution planner was designed to navigate transformable swarms in unstructured environments. To validate the proposed scheme, we applied Fe 3 O 4 nanoparticles swarms as a case study. The proposed scheme enables motion and pattern planning for microrobots of multiple sizes and reconfigurability in various working environments, which could foster a general navigation system for reconfigurable microswarms of different sizes.
Thailand is known to have various types of tropical fruits. Fruits are generally produced in large quantities annually. Preservation can add value and extend the shelf life of these fruit products. One of the most pop...
Thailand is known to have various types of tropical fruits. Fruits are generally produced in large quantities annually. Preservation can add value and extend the shelf life of these fruit products. One of the most popular methods of preservation is the drying process. A solar-powered dryer is widely used in fruit drying because of its low cost in terms of energy use. Ultrasonic vibration technology can be used to induce water movement in a product resulting in a faster dehydration rate. This can shorten the overall drying time and preserve the vitamins and nutrients in the product. In this work, the application of ultrasonic vibration to fruit drying was investigated. The raw material tested was pineapple. Drying was carried out in a hot air oven set to a temperature of 60 °C, with an applied vibration frequency of 40 kHz continuously for a short duration of 1 min. Three periods of the applied ultrasonic cycle (on for every 10, 20, 30 min) were tested for an overall drying time of 10 h. The results showed that for a cycle of every 10 min with vibration turned on, the initial moisture content of pineapples was reduced from 86.9 to 47.9 % wet basis at a maximum drying rate of 48.6 g/h, compared to 40.5 g/h from normal drying without applied vibration. The reduced drying time led to reduced energy consumption. This technique has the potential to be applied to other types of fruits and dryers.
Compared with traditional exoskeleton robots, the brain-computer interface (BCI) based lower limb exoskeleton system can directly control the robot by recording the user's brain activity signals, such as the elect...
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