Applied Sciences

Research

2525 KiB

Open AccessArticle

A Self-Paced P300 Healthcare Brain-Computer Interface System with SSVEP-Based Switching Control and Kernel FDA + SVM-Based Detector

by Yi-Hung Liu, Shih-Hao Wang and Ming-Ren Hu

Appl. Sci. 2016, 6(5), 142; https://doi.org/10.3390/app6050142 - 12 May 2016

Cited by 83 | Viewed by 6694

Abstract

This paper presents a novel brain-computer interface (BCI)-based healthcare control system, which is based on steady-state visually evoked potential (SSVEP) and P300 of electroencephalography (EEG) signals. The proposed system is composed of two modes, a brain switching mode and a healthcare function selection [...] Read more.

This paper presents a novel brain-computer interface (BCI)-based healthcare control system, which is based on steady-state visually evoked potential (SSVEP) and P300 of electroencephalography (EEG) signals. The proposed system is composed of two modes, a brain switching mode and a healthcare function selection mode. The switching mode can detect whether a user has the intent to activate the function selection mode by detecting SSVEP in an ongoing EEG. During the function selection mode, the user is able to select any functions that he/she wants to activate through a healthcare control panel, and the function selection is done by detecting P300 in the user’s EEG signals. The panel provides 25 functions representing 25 frequently performed activities of daily life. Therefore, users with severe motor disabilities can activate the system and any functions in a self-paced manner, achieving the goal of autonomous healthcare. To achieve high P300 detection accuracy, a novel P300 detector based on kernel Fisher’s discriminant analysis (kernel FDA) and support vector machine (SVM) is also proposed. Experimental results, carried out on five subjects, show that the proposed BCI system achieves high SSVEP detection (93%) and high P300 detection (95.5%) accuracies, meaning that the switching mode has a high sensitivity, and the function selection mode has the ability to accurately detect the functions that the users want to trigger. More important, only three electrodes (Oz, Cz, and Pz) are required to measure EEG signals, enabling the system to have good usability in practical use. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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6923 KiB

Open AccessArticle

A Novel Image Alignment Algorithm Based on Rotation-Discriminating Ring-Shifted Projection for Automatic Optical Inspection

by Chin-Sheng Chen and Chien-Liang Huang

Appl. Sci. 2016, 6(5), 140; https://doi.org/10.3390/app6050140 - 9 May 2016

Cited by 2 | Viewed by 6218

Abstract

This paper proposes a novel image alignment algorithm based on rotation-discriminating ring-shifted projection for automatic optical inspection. This new algorithm not only identifies the location of the template image within an inspection image but also provides precise rotation information during the template-matching process [...] Read more.

This paper proposes a novel image alignment algorithm based on rotation-discriminating ring-shifted projection for automatic optical inspection. This new algorithm not only identifies the location of the template image within an inspection image but also provides precise rotation information during the template-matching process by using a novel rotation estimation scheme, the so-called ring-shifted technique. We use a two stage framework with an image pyramid searching technique for realizing the proposed image alignment algorithm; in the first stage, the similarity based on hybrid projection transformation with the image pyramid searching technique is employed for quick selection and location of the candidates in the inspection image. In the second stage, the rotation angle of the object is estimated by a novel ring-shifted technique. The estimation is performed only for the most likely candidate which is the one having the highest similarity in the first stage. The experimental results show that the proposed method provides accurate estimation for template matching with arbitrary rotations and is applicable in various environmental conditions. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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3106 KiB

Open AccessArticle

Development of Intelligent Fuzzy Controller for a Two-Axis Solar Tracking System

by Cong-Hui Huang, Heng-Yau Pan and Kuan-Chen Lin

Appl. Sci. 2016, 6(5), 130; https://doi.org/10.3390/app6050130 - 3 May 2016

Cited by 30 | Viewed by 9580

Abstract

This paper proposes the development of a two-axis sun tracking solar energy system using fuzzy logic as intelligent quality policy. To achieve maximum efficiency for solar panels, it is necessary to follow the sun’s path in the sky. Therefore, the architecture for the [...] Read more.

This paper proposes the development of a two-axis sun tracking solar energy system using fuzzy logic as intelligent quality policy. To achieve maximum efficiency for solar panels, it is necessary to follow the sun’s path in the sky. Therefore, the architecture for the two-axis sun tracking solar energy system uses software to control the hardware. The hardware comprises (i) solar cells; (ii) lead-acid batteries; (iii) a gear box; (iv) a stepping motor; and (v) a light detection circuit, while the software comprises (i) a detection system; (ii) a fuzzy tracking controller; and (iii) a database system. A fuzzy logic controller is designed as the software architecture of the system to decide the timing for tracking the sun. The nearest position that results in receiving direct sunlight is obtained from the database. Our system is fully automatic in a changing environment and takes into account meteorological changes and the effects of the external environment arising from a malfunction. This approach reduces the number of starting motors and results in smaller energy loss in cloudy, cloud mask, or unstable weather conditions. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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5671 KiB

Open AccessArticle

Quantitative Assessment of Variational Surface Reconstruction from Sparse Point Clouds in Freehand 3D Ultrasound Imaging during Image-Guided Tumor Ablation

by Shuangcheng Deng, Yunhua Li, Lipei Jiang and Ping Liang

Appl. Sci. 2016, 6(4), 114; https://doi.org/10.3390/app6040114 - 19 Apr 2016

Cited by 1 | Viewed by 6961

Abstract

Surface reconstruction for freehand 3D ultrasound is used to provide 3D visualization of a VOI (volume of interest) during image-guided tumor ablation surgery. This is a challenge because the recorded 2D B-scans are not only sparse but also non-parallel. To solve this issue, [...] Read more.

Surface reconstruction for freehand 3D ultrasound is used to provide 3D visualization of a VOI (volume of interest) during image-guided tumor ablation surgery. This is a challenge because the recorded 2D B-scans are not only sparse but also non-parallel. To solve this issue, we established a framework to reconstruct the surface of freehand 3D ultrasound imaging in 2011. The key technique for surface reconstruction in that framework is based on variational interpolation presented by Greg Turk for shape transformation and is named Variational Surface Reconstruction (VSR). The main goal of this paper is to evaluate the quality of surface reconstructions, especially when the input data are extremely sparse point clouds from freehand 3D ultrasound imaging, using four methods: Ball Pivoting, Power Crust, Poisson, and VSR. Four experiments are conducted, and quantitative metrics, such as the Hausdorff distance, are introduced for quantitative assessment. The experiment results show that the performance of the proposed VSR method is the best of the four methods at reconstructing surface from sparse data. The VSR method can produce a close approximation to the original surface from as few as two contours, whereas the other three methods fail to do so. The experiment results also illustrate that the reproducibility of the VSR method is the best of the four methods. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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5044 KiB

Open AccessArticle

Real-Time Compensation for Thermal Errors of the Milling Machine

by Tsung-Chia Chen, Chia-Jung Chang, Jui-Pin Hung, Rong-Mao Lee and Cheng-Chi Wang

Appl. Sci. 2016, 6(4), 101; https://doi.org/10.3390/app6040101 - 7 Apr 2016

Cited by 32 | Viewed by 6486

Abstract

This paper is focused on developing a compensation module for reducing the thermal errors of a computer numerical control (CNC) milling machine. The thermal induced displacement variations of machine tools are a vital problem that causes positioning errors to be over than 65%. [...] Read more.

This paper is focused on developing a compensation module for reducing the thermal errors of a computer numerical control (CNC) milling machine. The thermal induced displacement variations of machine tools are a vital problem that causes positioning errors to be over than 65%. To achieve a high accuracy of machine tools, it is important to find the effective methods for reducing the thermal errors. To this end, this study first used 14 temperature sensors to examine the real temperature fields around the machine, from which four points with high sensitivity to temperature rise were selected as the major locations for creating the representative thermal model. With the model, the compensation system for controlling the displacement variation was developed. The proposed model has been applied to the milling machine. Current results show that the displacement variations on the x- and y-axes and the position error at the tool center were controlled within 20 µm when the compensation system was activated. The feasibility of the compensation system was successfully demonstrated in application on the milling operation. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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9808 KiB

Open AccessArticle

Hybrid Robust Control Law with Disturbance Observer for High-Frequency Response Electro-Hydraulic Servo Loading System

by Zhiqing Sheng and Yunhua Li

Appl. Sci. 2016, 6(4), 98; https://doi.org/10.3390/app6040098 - 6 Apr 2016

Cited by 17 | Viewed by 7250

Abstract

Addressing the simulating issue of the helicopter-manipulating booster aerodynamic load with high-frequency dynamic load superimposed on a large static load, this paper studies the design of the robust controller for the electro-hydraulic loading system to realize the simulation of this kind of load. [...] Read more.

Addressing the simulating issue of the helicopter-manipulating booster aerodynamic load with high-frequency dynamic load superimposed on a large static load, this paper studies the design of the robust controller for the electro-hydraulic loading system to realize the simulation of this kind of load. Firstly, the equivalent linear model of the electro-hydraulic loading system under assumed parameter uncertainty is established. Then, a hybrid control scheme is proposed for the loading system. This control scheme consists of a constant velocity feed-forward compensator, a robust inner loop compensator based on disturbance observer and a robust outer loop feedback controller. The constant velocity compensator eliminates most of the extraneous force at first, and then the double-loop cascade composition control strategy is employed to design the compensated system. The disturbance observer–based inner loop compensator further restrains the disturbances including the remaining extraneous force, and makes the actual plant tracking a nominal model approximately in a certain frequency range. The robust outer loop controller achieves the desired force-tracking performance, and guarantees system robustness in the high frequency region. The optimized low-pass filter Q(s) is designed by using the H∞ mixed sensitivity optimization method. The simulation results show that the proposed hybrid control scheme and controller can effectively suppress the extraneous force and improve the robustness of the electro-hydraulic loading system. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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4291 KiB

Open AccessArticle

The Development of an Optimal Control Strategy for a Series Hydraulic Hybrid Vehicle

by Chih-Wei Hung, Tri-Vien Vu and Chih-Keng Chen

Appl. Sci. 2016, 6(4), 93; https://doi.org/10.3390/app6040093 - 28 Mar 2016

Cited by 11 | Viewed by 6889

Abstract

In this work, a Truck Class II series hydraulic hybrid model is established. Dynamic Programming (DP) methodology is applied to derive the optimal power-splitting factor for the hybrid system for preselected driving schedules. Implementable rules are derived by extracting the optimal trajectory features [...] Read more.

In this work, a Truck Class II series hydraulic hybrid model is established. Dynamic Programming (DP) methodology is applied to derive the optimal power-splitting factor for the hybrid system for preselected driving schedules. Implementable rules are derived by extracting the optimal trajectory features from a DP scheme. The system behaviors illustrate that the improved control strategy gives a highly effective operation region for the engine and high power density characteristics for the hydraulic components. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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2651 KiB

Open AccessArticle

Reconfiguration for the Maximum Dynamic Wrench Capability of a Parallel Robot

by Chih-Jer Lin and Chun-Ta Chen

Appl. Sci. 2016, 6(3), 80; https://doi.org/10.3390/app6030080 - 16 Mar 2016

Cited by 5 | Viewed by 5475

Abstract

In this paper, a Stewart-platform robot with sliding lockable base joints is proposed for reconfiguration, and it addresses the determination of the optimal configuration for the prescribed motion with maximum allowable dynamic wrench capability subject to the constraints imposed by the kinematics and [...] Read more.

In this paper, a Stewart-platform robot with sliding lockable base joints is proposed for reconfiguration, and it addresses the determination of the optimal configuration for the prescribed motion with maximum allowable dynamic wrench capability subject to the constraints imposed by the kinematics and dynamics of the proposed reconfigurable architecture. The numerical results from the hierarchical optimization process allow us to investigate the effects of the base point locations on the maximum dynamic wrench capability. The effectiveness of the proposed algorithm is demonstrated in the improvement of the maximum allowable dynamic wrench capability of the reconfigurable Stewart-platform robot. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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12399 KiB

Open AccessArticle

Remote Control of a Mobile Robot for Indoor Patrol

by Shih-Yao Juang and Jih-Gau Juang

Appl. Sci. 2016, 6(3), 82; https://doi.org/10.3390/app6030082 - 15 Mar 2016

Cited by 6 | Viewed by 7020

Abstract

This study applies smartphone, Bluetooth, and Wi-Fi wireless network to control a wheeled mobile robot (WMR) remotely. The first part of this study demonstrates that the WMR can be controlled manually by a smartphone. The smartphone can remotely control the WMR for forward, [...] Read more.

This study applies smartphone, Bluetooth, and Wi-Fi wireless network to control a wheeled mobile robot (WMR) remotely. The first part of this study demonstrates that the WMR can be controlled manually by a smartphone. The smartphone can remotely control the WMR for forward, backward, left-turn, and right-turn operations. The second part of this article presents object tracking. The WMR can follow a moving object through the use of image processing for object tracking and distance detection. In the third part, infrared sensor and fuzzy system algorithms are integrated into the control scheme. Through wall-following and obstacle-avoidance control, the WMR can successfully perform indoor patrol. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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4489 KiB

Open AccessArticle

Investigation of the Machining Stability of a Milling Machine with Hybrid Guideway Systems

by Jui-Pin Hung, Wei-Zhu Lin, Yong-Jun Chen and Tzou-Lung Luo

Appl. Sci. 2016, 6(3), 76; https://doi.org/10.3390/app6030076 - 8 Mar 2016

Cited by 7 | Viewed by 8568

Abstract

This study was aimed to investigate the machining stability of a horizontal milling machine with hybrid guideway systems by finite element method. To this purpose, we first created finite element model of the milling machine with the introduction of the contact stiffness defined [...] Read more.

This study was aimed to investigate the machining stability of a horizontal milling machine with hybrid guideway systems by finite element method. To this purpose, we first created finite element model of the milling machine with the introduction of the contact stiffness defined at the sliding and rolling interfaces, respectively. Also, the motorized built-in spindle model was created and implemented in the whole machine model. Results of finite element simulations reveal that linear guides with different preloads greatly affect the dynamic responses and machining stability of the horizontal milling machine. The critical cutting depth predicted at the vibration mode associated with the machine tool structure is about 10 mm and 25 mm in the X and Y direction, respectively, while the cutting depth predicted at the vibration mode associated with the spindle structure is about 6.0 mm. Also, the machining stability can be increased when the preload of linear roller guides of the feeding mechanism is changed from lower to higher amount. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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841 KiB

Open AccessArticle

Evaluating Performance of the DGM(2,1) Model and Its Modified Models

by Ying-Fang Huang, Chia-Nan Wang, Hoang-Sa Dang and Shun-Te Lai

Appl. Sci. 2016, 6(3), 73; https://doi.org/10.3390/app6030073 - 4 Mar 2016

Cited by 18 | Viewed by 5095

Abstract

The direct grey model (DGM(2,1)) is considered for fluctuation characteristics of the sampling data in Grey system theory. However, its applications are quite uncommon in the past literature. The improvement of the precision of the DGM(2,1) is only presented in few previous researches. [...] Read more.

The direct grey model (DGM(2,1)) is considered for fluctuation characteristics of the sampling data in Grey system theory. However, its applications are quite uncommon in the past literature. The improvement of the precision of the DGM(2,1) is only presented in few previous researches. Moreover, the evaluation of forecasted performance of the DGM(2,1) model and its applications was not conducted in previous studies. As the results, this study aims to evaluate forecasted performance of the DGM(2,1) and its three modified models, including the Markov direct grey model MDGM(2,1), the Fourier direct grey model FDGM(2,1), and the Fourier Markov direct grey model FMDGM(2,1) in order to determine the application of the DGM(2,1) model in practical applications and academic research. The results demonstrate that the DGM(2,1) model has lower precision than its modified models, while the forecasted precision of the FDGM(2,1) is better than that of MDGM(2,1). Additionally, the FMDGM(2,1) model presents the best performance among all of the modified models of DGM(2,1), which can effectively overcome the fluctuating of the data sample and minimize the predicted error of the DGM(2,1) model. The finding indicated that the FMDGM(2,1) model does not only have advantages with regard to the sample size requirement, but can also be flexibly applied to the large fluctuation and random sequences with a high quality of estimation. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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8394 KiB

Open AccessArticle

Adaptive Control of Active Magnetic Bearing against Milling Dynamics

by Rong-Mao Lee and Tsung-Chia Chen

Appl. Sci. 2016, 6(2), 52; https://doi.org/10.3390/app6020052 - 15 Feb 2016

Cited by 7 | Viewed by 8517

Abstract

For improving the defects in milling processes caused by traditional spindle bearings, e.g., the dimensional discrepancy of a finished workpiece due to bearing wear or oil pollution by lubricant, a novel embedded cylindrical-array magnetic actuator (ECAMA) is designed for milling applications. Since ECAMA [...] Read more.

For improving the defects in milling processes caused by traditional spindle bearings, e.g., the dimensional discrepancy of a finished workpiece due to bearing wear or oil pollution by lubricant, a novel embedded cylindrical-array magnetic actuator (ECAMA) is designed for milling applications. Since ECAMA is a non-contact type actuator, a control strategy named fuzzy model-reference adaptive control (FMRAC) is synthesized to account for the nonlinearities of milling dynamics and magnetic force. In order to ensure the superior performance of spindle position regulation, the employed models in FMRAC are all constructed by experiments. Based on the experimental results, the magnetic force by ECAMA is much stronger than that by the traditional active magnetic bearing (AMB) design under the same test conditions and identical overall size. The efficacy of ECAMA to suppress the spindle position deviation with the aid of FMRAC has been verified as well via numerical simulations and practical metal cutting. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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4647 KiB

Open AccessArticle

Method for Analysis of an Offshore Heave Compensator

by Gwi-Nam Kim, Sung-Gu Hwang, Jang-Hwan Hyeon, Young-Hwan Yoon, Yong-Gil Jung and Sun-Chul Huh

Appl. Sci. 2016, 6(2), 51; https://doi.org/10.3390/app6020051 - 8 Feb 2016

Cited by 3 | Viewed by 5788

Abstract

A heave compensation system consists of a drill string compensator (DSC) and an active heave compensator (AHC) cylinder, which together produce control force over an oil pressure system suitable for transmission of considerable power and compensating for heaving motion of the hull during [...] Read more.

A heave compensation system consists of a drill string compensator (DSC) and an active heave compensator (AHC) cylinder, which together produce control force over an oil pressure system suitable for transmission of considerable power and compensating for heaving motion of the hull during drilling work. In this study, a heave compensator of an oil pressure system was simulated to draw a conclusion, which was verified by comparison with the result of a test conducted using an actual miniature model. The compensation rate was 95%, based on which the dynamic behaviors of an actual-size heave compensator were presumed. Furthermore, the speed of each cylinder and the acceleration of heave can be determined and used to fabricate an actual-size heave compensator. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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4095 KiB

Open AccessArticle

Design of an Image-Servo Mask Alignment System Using Dual CCDs with an XXY Stage

by Chih-Jer Lin, Hui-Hsiang Hsu, Chiang-Ho Cheng and Yu-Chung Li

Appl. Sci. 2016, 6(2), 42; https://doi.org/10.3390/app6020042 - 2 Feb 2016

Cited by 9 | Viewed by 8199

Abstract

Mask alignment of photolithography technology is used in many applications, such as micro electro mechanical systems’ semiconductor process, printed circuits board, and flat panel display. As the dimensions of the product are getting smaller and smaller, the automatic mask alignment of photolithography is [...] Read more.

Mask alignment of photolithography technology is used in many applications, such as micro electro mechanical systems’ semiconductor process, printed circuits board, and flat panel display. As the dimensions of the product are getting smaller and smaller, the automatic mask alignment of photolithography is becoming more and more important. The traditional stacked XY-Θz stage is heavy and it has cumulative flatness errors due to its stacked assembly mechanism. The XXY stage has smaller cumulative error due to its coplanar design and it can move faster than the traditional XY-Θz stage. However, the relationship between the XXY stage’s movement and the commands of the three motors is difficult to compute, because the movements of the three motors on the same plane are coupling. Therefore, an artificial neural network is studied to establish a nonlinear mapping from the desired position and orientation of the stage to three motors’ commands. Further, this paper proposes an image-servo automatic mask alignment system, which consists of a coplanar XXY stage, dual GIGA-E CCDs with lens and a programmable automatic controller (PAC). Before preforming the compensation, a self-developed visual-servo provides the positioning information which is obtained from the image processing and pattern recognition according to the specified fiducial marks. To obtain better precision, two methods including the center of gravity method and the generalize Hough Transformation are studied to correct the shift positioning error. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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18419 KiB

Open AccessArticle

Fault-Tolerant Visual Secret Sharing Schemes without Pixel Expansion

by Justie Su-Tzu Juan, Yung-Chang Chen and Song Guo

Appl. Sci. 2016, 6(1), 18; https://doi.org/10.3390/app6010018 - 14 Jan 2016

Cited by 4 | Viewed by 5698

Abstract

Visual cryptography encrypts a secret image into two meaningless random images, called shares, such that it can be decrypted by human vision without any calculations. However, there would be problems in alignment when these two shares are staked by hand in practice. Therefore, [...] Read more.

Visual cryptography encrypts a secret image into two meaningless random images, called shares, such that it can be decrypted by human vision without any calculations. However, there would be problems in alignment when these two shares are staked by hand in practice. Therefore, this paper presents the fault-tolerant schemes of stacking two shares that are acquired from secret image encryption without pixel expansion. The main idea of these schemes is to combine several pixels as a unit and then to encrypt each unit into a specific combination of pixels. Both theoretical analysis and simulation results demonstrate the effectiveness and practicality of the proposed schemes. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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1850 KiB

Open AccessArticle

A Synchrophasor Based Optimal Voltage Control Scheme with Successive Voltage Stability Margin Improvement

by Heng-Yi Su, Yi-Chung Chen and Yu-Liang Hsu

Appl. Sci. 2016, 6(1), 14; https://doi.org/10.3390/app6010014 - 7 Jan 2016

Cited by 7 | Viewed by 5658

Abstract

This paper proposes an optimal control scheme based on a synchronized phasor (synchrophasor) for power system secondary voltage control. The framework covers voltage stability monitoring and control. Specifically, a voltage stability margin estimation algorithm is developed and built in the newly designed adaptive [...] Read more.

This paper proposes an optimal control scheme based on a synchronized phasor (synchrophasor) for power system secondary voltage control. The framework covers voltage stability monitoring and control. Specifically, a voltage stability margin estimation algorithm is developed and built in the newly designed adaptive secondary voltage control (ASVC) method to achieve more reliable and efficient voltage regulation in power systems. This new approach is applied to improve voltage profile across the entire power grid by an optimized plan for VAR (reactive power) sources allocation; therefore, voltage stability margin of a power system can be increased to reduce the risk of voltage collapse. An extensive simulation study on the IEEE 30-bus test system is carried out to demonstrate the feasibility and effectiveness of the proposed scheme. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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13682 KiB

Open AccessArticle

Image Hiding Scheme Based on the Atrial Fibrillation Model

by Martynas Vaidelys, Jurate Ragulskiene, Pranas Ziaukas and Minvydas Ragulskis

Appl. Sci. 2015, 5(4), 1980-1991; https://doi.org/10.3390/app5041980 - 21 Dec 2015

Cited by 4 | Viewed by 5697

Abstract

An image communication scheme based on the atrial fibrillation (AF) model is presented in this paper. Self-organizing patterns produced by the AF model are used to hide and transmit secret visual information. A secret image is encoded into the random matrix of initial [...] Read more.

An image communication scheme based on the atrial fibrillation (AF) model is presented in this paper. Self-organizing patterns produced by the AF model are used to hide and transmit secret visual information. A secret image is encoded into the random matrix of initial cell excitation states in the form of a dot-skeleton representation. Self-organized patterns produced by such initial cell states ensure a secure and efficient transmission of secret visual images. Procedures for digital encoding and decoding of secret images, as well as the sensitivity of the communication scheme to the perturbation of the AF model’s parameters are discussed in the paper. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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5381 KiB

Open AccessArticle

Numerical Simulation of Laminar Forced Convection of Pin-Fin Heat-Sink Array in a Channel by Using Porous Approach

by Tzer-Ming Jeng and Sheng-Chung Tzeng

Appl. Sci. 2015, 5(4), 1846-1868; https://doi.org/10.3390/app5041846 - 16 Dec 2015

Cited by 10 | Viewed by 7887

Abstract

This work used a porous approach model to numerically investigate the fluid flow and heat transfer characteristics of the pin-fin heat-sink array in a rectangular channel with in-line arrangement. The air flow through the channel was laminar. The pin-fin heat sinks with various [...] Read more.

This work used a porous approach model to numerically investigate the fluid flow and heat transfer characteristics of the pin-fin heat-sink array in a rectangular channel with in-line arrangement. The air flow through the channel was laminar. The pin-fin heat sinks with various porosities and pin-fin numbers were employed. The relative center-to-center longitudinal and transverse distances between adjacent heat sinks were changed. The results indicate that the Nusselt number of various heat-sink arrays increased with decreasing the relative center-to-center transverse distance, but not varied with the relative center-to-center longitudinal distance. For the typical pin-fin heat-sink arrays, the Nusselt number changed slightly for the heat sinks with 0.358–0.556 porosity, but increased by 11.7%–24.8% when the porosity increased from 0.556 to 0.750, and then dropped obviously when the porosity exceeded 0.750. Increasing the number of pin fins continuously could increase Nusselt number. However, when the number of pin fins was large, the Nusselt number increased with the number of pin fins slowly. The present numerical simulation has been validated by the typical experiment. Finally, a semi-empirical correlation of Nusselt number for each heat sink in the heat-sink array was proposed. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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954 KiB

Open AccessArticle

Quantum Wind Driven Optimization for Unmanned Combat Air Vehicle Path Planning

by Yongquan Zhou, Zongfan Bao, Rui Wang, Shilei Qiao and Yuxiang Zhou

Appl. Sci. 2015, 5(4), 1457-1483; https://doi.org/10.3390/app5041457 - 30 Nov 2015

Cited by 21 | Viewed by 5525

Abstract

Unmanned combat air vehicle (UCAV) path planning aims to calculate the optimal or suboptimal flight path considering the different threats and constraints under the complex battlefield environment. This flight path can help the UCAV avoid enemy threats and improve the efficiency of the [...] Read more.

Unmanned combat air vehicle (UCAV) path planning aims to calculate the optimal or suboptimal flight path considering the different threats and constraints under the complex battlefield environment. This flight path can help the UCAV avoid enemy threats and improve the efficiency of the investigation. This paper presents a new quantum wind driven optimization (QWDO) for the path planning of UCAV. QWDO algorithm uses quantum rotation gate strategy on population evolution and the quantum non-gate strategy to realize the individual variation of population. These operations improve the diversity of population and avoid premature convergence. This paper tests this optimization in two instances. The experimental results show that the proposed algorithm is feasible in these two cases. Compared to quantum bat algorithm (QBA), quantum particle swarm optimization (QPSO), wind driven optimization (WDO), bat algorithm (BA), particle swarm optimization (PSO), and differential evolution (DE), the QWDO algorithm exhibited better performance. The simulation results demonstrate that the QWDO algorithm is an effective and feasible method for solving UCAV path planning. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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817 KiB

Open AccessArticle

Development of a Fractional Order Chaos Synchronization Dynamic Error Detector for Maximum Power Point Tracking of Photovoltaic Power Systems

by Kuo-Nan Yu, Her-Terng Yau and Chi-Kang Liao

Appl. Sci. 2015, 5(4), 1117-1133; https://doi.org/10.3390/app5041117 - 12 Nov 2015

Cited by 6 | Viewed by 4351

Abstract

In recent years, the photovoltaic (PV) power generation system has been widely discussed and researched. Research on electric energy focuses on the development of Maximum Power Point Tracking (MPPT) technology, and many methods have been proposed. However, these studies have a common defect: [...] Read more.

In recent years, the photovoltaic (PV) power generation system has been widely discussed and researched. Research on electric energy focuses on the development of Maximum Power Point Tracking (MPPT) technology, and many methods have been proposed. However, these studies have a common defect: the tracking continues near the maximum power point (MPP), so that the waveform of output power jitters, thus causing power loss and rapid wearing of electronic modules. In order to remedy this defect, this paper proposes a new type of fractional order chaos synchronization dynamic error detector for the MPPT design of a PV power system. In this study, the Sprott chaos synchronization dynamic error system was used to control the pulse width duty cycle of PWM and optimize the power oscillation of a PV power system during steady-state response. The simulation and experimental results showed that the voltage detector proposed in this paper can reduce the power oscillation of a PV power system during steady-state response, and increase the overall system efficiency. From the steady-state responses of MPPT, it can be seen that about 0.2 vibration amplitude can be suppressed with control action. Therefore, about 4% of steady-state vibration energy can be saved. Full article

(This article belongs to the Special Issue Intelligence Computational and Control Approaches for Multi-Physic Coupling Engineering Systems)

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