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4145 KiB

Open AccessArticle

Numerical and Experimental Study on Enhancing Performance of the Stand Fan

by Sheam-Chyun Lin, Ming-Chiou Shen, Hao-Ru Tso, Hung-Cheng Yen and Yu-Cheng Chen

Appl. Sci. 2017, 7(3), 267; https://doi.org/10.3390/app7030267 - 8 Mar 2017

Cited by 5 | Viewed by 7251

Abstract

To meet humans’ need of enhancing the quality of life, the high-performance stand fan has become an essential appliance in every family. On the other hand, energy saving can not only solve the problem of environment protection, but also can reduce the cost [...] Read more.

To meet humans’ need of enhancing the quality of life, the high-performance stand fan has become an essential appliance in every family. On the other hand, energy saving can not only solve the problem of environment protection, but also can reduce the cost of energy consumption. However, the aerodynamic performance and flow characteristics of the stand fan are rarely investigated and analyzed in a systematical manner. Therefore, this research intends to investigate the physical mechanism of the flow pattern and identify the design parameters of the stand fan by combining numerical and experimental methods. First of all, both the structure and performance of a commercial 14-inch stand fan are chosen for analysis and are set as the reference for the fan. The stand fan can be divided into the impeller and the protective cover. Clearly, the impeller blades have a great influence on the fan performance, so they are the first design target. In this work, CFD (computational fluid dynamics) software Fluent (version 14.5, ANSYS Inc., Canonsburg, PA, USA, 2012) is used to analyze and observe the corresponding influences on flow fields and aerodynamic performance by changing the design parameters such as the setting, twist, and inclination angles. Then, the protective cover is studied, improved and integrated with the designed impeller to further enhance the performance of the fan. The protective cover is modified by varying the spacing between the blade tip and cover, as well as varying the shape and angle of ribs to improve the fan’s flow field and performance. Finally, the optimal fan mockup is made via CNC (computer numerical control) technology. Also, its acoustics and performance have been measured to validate the accuracy and reliability of the numerical simulation. The testing results show that the optimally designed stand fan is better than the reference fan with a significant 54% increase in max flow rate. In addition, it has more uniform velocity distribution compared with the reference fan to achieve a comfortable feeling for the human body. In summary, this research successfully establishes a reliable and systematic scheme to design the stand fan. Also, the corresponding performance influences caused by those important parameters are analyzed and summarized to serve as the design reference for the stand fan. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3244 KiB

Open AccessArticle

Block Recovery Rate-Based Unequal Error Protection for Three-Screen TV

by Hojin Ha and Eun-Seok Ryu

Appl. Sci. 2017, 7(2), 186; https://doi.org/10.3390/app7020186 - 16 Feb 2017

Viewed by 4239

Abstract

This paper describes a three-screen television system using a block recovery rate (BRR)-based unequal error protection (UEP). The proposed in-home wireless network uses scalable video coding (SVC) and UEP with forward error correction (FEC) for maximizing the quality of service (QoS) over error-prone [...] Read more.

This paper describes a three-screen television system using a block recovery rate (BRR)-based unequal error protection (UEP). The proposed in-home wireless network uses scalable video coding (SVC) and UEP with forward error correction (FEC) for maximizing the quality of service (QoS) over error-prone wireless networks. For efficient FEC packet assignment, this paper proposes a simple and efficient performance metric, a BRR which is defined as a recovery rate of temporal and quality layer from FEC assignment by analyzing the hierarchical prediction structure including the current packet loss. It also explains the SVC layer switching scheme according to network conditions such as packet loss rate (PLR) and available bandwidth (ABW). In the experiments conducted, gains in video quality with the proposed UEP scheme vary from 1 to 3 dB in Y-peak signal-to-noise ratio (PSNR) with corresponding subjective video quality improvements. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3429 KiB

Open AccessArticle

A Real-Time Computation Model of the Electromagnetic Force and Torque for a Maglev Planar Motor with the Concentric Winding

by Baoquan Kou, Feng Xing, Lu Zhang, Chaoning Zhang and Yiheng Zhou

Appl. Sci. 2017, 7(1), 98; https://doi.org/10.3390/app7010098 - 20 Jan 2017

Cited by 17 | Viewed by 6392

Abstract

The traditional model of the electromagnetic force and torque does not take the coil corners into account, which is the major cause for the motor fluctuation. To reduce the fluctuation, a more accurate real-time computation model, which considers the influence of the coil [...] Read more.

The traditional model of the electromagnetic force and torque does not take the coil corners into account, which is the major cause for the motor fluctuation. To reduce the fluctuation, a more accurate real-time computation model, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems respectively for the stator, the mover, and the corner are established. The first harmonic of the magnetic flux density distribution of a Halbach magnet array is taken into account in this model. The coil is divided into the straight coil segment and the corner coil segment based on its structure. For the straight coil segment, the traditional Lorenz force method can be used to compute its electromagnetic force and torque, which is a function of the mover position. For the corner coil segment, however, the numerical calculation method can be used to get its respective electromagnetic force and torque. Based on the above separate analysis, an electromagnetic model can be derived, which is suitable for practical application. Compared with the well-known harmonic model, the proposed real-time computation model is found to have less model inaccuracy. Additionally, the real-time ability of the maglev planar motor model and the decoupling computation is validated by NI PXI platform (Austin, TX, USA). Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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7262 KiB

Open AccessArticle

Flexural Capacity of a New Composite Beam with Concrete-Infilled Tubular Lower Flange

by Bong-Ho Cho, Jae-Sub Lee, Young-Ho Kim and Dae-Jin Kim

Appl. Sci. 2017, 7(1), 57; https://doi.org/10.3390/app7010057 - 6 Jan 2017

Cited by 2 | Viewed by 7615

Abstract

This paper proposes a new steel concrete composite beam that has a similar shape to the conventional steel wide flange beam, but whose lower flange has a tubular shape with infilled concrete. It has openings in the web for perfect integration between concrete [...] Read more.

This paper proposes a new steel concrete composite beam that has a similar shape to the conventional steel wide flange beam, but whose lower flange has a tubular shape with infilled concrete. It has openings in the web for perfect integration between concrete and steel materials, and the tubular lower flange is reinforced with steel rebars to enhance its flexural strength. The bending capacity of the new composite beam was investigated by performing a two-point loading test on seven specimens, which can be categorized mainly into two types, non-composite and fully composite specimens. The load versus displacement curves were plotted for all the specimens and their failure modes were identified. Theoretical equations were proposed to estimate the flexural strength of the new composite beam members, and their accuracy was examined by comparing the predictions of the equations with the test results. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3350 KiB

Open AccessArticle

Design and Optimization of a Lorentz-Force-Driven Planar Motor

by He Zhang and Baoquan Kou

Appl. Sci. 2017, 7(1), 7; https://doi.org/10.3390/app7010007 - 22 Dec 2016

Cited by 5 | Viewed by 7170

Abstract

This paper describes a short-stroke Lorentz-force-driven planar motor which can realize three-degree-of-freedom motions in high-precision positioning systems. It is an extended version of our previous publication. Based on the analytical model, the force expression concerning the main dimensional parameters is derived. Compared with [...] Read more.

This paper describes a short-stroke Lorentz-force-driven planar motor which can realize three-degree-of-freedom motions in high-precision positioning systems. It is an extended version of our previous publication. Based on the analytical model, the force expression concerning the main dimensional parameters is derived. Compared with the finite element simulation, the optimization method in this paper is completely based on the mathematical model, which saves considerable time and has clear physical meaning. The effect of the main parameters on the motor performances such as force, force density, and acceleration are analyzed. This information can provide important design references for researchers. Finally, one prototype is tested. The testing values for the resistance and inductance of the square coil agree well with the analytical values. Additionally, the measured forces show a good agreement with the analytical force expression, and the force characteristics show a good symmetry in the x and y directions. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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5659 KiB

Open AccessArticle

Numerical Simulation and Experimental Validation for the Thermal Analysis of a Compact LED Recessed Downlight with Heat Sink Design

by Huan-Chu Hsu and Yi-Cheng Huang

Appl. Sci. 2017, 7(1), 4; https://doi.org/10.3390/app7010004 - 22 Dec 2016

Cited by 11 | Viewed by 6713

Abstract

Light emitting diode (LED)-recessed downlighting is currently mainly used for indoor lighting of residential and commercial buildings. Maintaining a low junction temperature and increasing the lifetime and reliability of LED lighting is desirable. This study investigated designed heat sinks’ heat dissipation and capability [...] Read more.

Light emitting diode (LED)-recessed downlighting is currently mainly used for indoor lighting of residential and commercial buildings. Maintaining a low junction temperature and increasing the lifetime and reliability of LED lighting is desirable. This study investigated designed heat sinks’ heat dissipation and capability of maintaining a low junction temperature, as well as increases in the lifetime and reliability of the lighting. This paper presents a designed traditional trapezoidal aluminum finned heat sink (ALFHS) and annular open cell copper foam heat sink (CUFHS) mounted to a 10 W compact LED-recessed downlight (CLRDL) and individually installed in a simulation 105 mm × 105 mm × 100 mm (L × W × H) test box. The purpose was to evaluate the temperature performance by testing the downlight in a small enclosed space with high ambient temperature while the LED is in operation. The downlight exhibited a long lifetime at normal use temperature and functioned according to Arrhenius’ law. Numerical simulation was performed first and followed by experimental validation. The heat sink design was the main factor in the heat management of the CLRDL. The heat sinks height was determined using numerical simulation and experimental validation before and after installation (INST) of the ALFHS and CUFHS. The CUFHS height was initially selected based on a larger heat dissipation capacity, and then by determining the ALFHS height. Both the ALFHS and CUFHS with the same height of 17 mm exhibited a similar capacity of heat dissipation before INST. Subsequent to INST, the temperature of the solder point of the ALFHS was higher than that of the CUFHS with an identical height of 17 mm. To compare the heat dissipation behavior of the two heat sinks, the ALFHS height was increased to 23 mm, which is 6 mm higher than that of the CUFHS. The results of a stationary simulation study for junction temperature coincides with the experimental results tested obtained using J-type thermocouples and a data acquisition system. The temperature of the solder point of the CLRDL with both the ALFHS and CUFHS was 91.7 °C after INST, corresponding to an LED junction temperature of 121.7 °C, which is lower than specified 135 °C LED limit temperature. The temperature distributions of specified points under natural convection were evaluated. The CLRDL installed in a small enclosed space withstood the lifetime requirements according to the results of an accelerated life test prediction. The CLRDL lumen maintenance was tested to be more than 25,000 h. The experimental results demonstrate compliance with the Energy Star^® requirements for indoor LED lighting fixtures. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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2467 KiB

Open AccessArticle

Dominant Channel Occupancy for Wi-Fi Backscatter Uplink in Industrial Internet of Things

by Jung-Hyok Kwon, Hwi-Ho Lee, Yongseok Lim and Eui-Jik Kim

Appl. Sci. 2016, 6(12), 427; https://doi.org/10.3390/app6120427 - 13 Dec 2016

Cited by 15 | Viewed by 5028

Abstract

This paper presents a dominant channel occupancy (DCO) mechanism for the Wi-Fi backscatter uplink in the industrial Internet of things (IIoT). The DCO provides high-priority channel access and reliable burst transmission to the Wi-Fi backscatter devices, thereby enabling the Wi-Fi backscatter tag to [...] Read more.

This paper presents a dominant channel occupancy (DCO) mechanism for the Wi-Fi backscatter uplink in the industrial Internet of things (IIoT). The DCO provides high-priority channel access and reliable burst transmission to the Wi-Fi backscatter devices, thereby enabling the Wi-Fi backscatter tag to deliver its tag information to the Wi-Fi reader without interference from neighboring legacy Wi-Fi devices to guarantee the timeliness and reliability of the IIoT system. For the former, we consider three types of medium access control (MAC) configurations: “carrier sense multiple access with collision avoidance (CSMA/CA) starting with short inter-frame space (SIFS)”, “freezing of the backoff period”, and “reduced CW_min.” In addition, the DCO uses the SIFS between burst packets to guarantee reliable burst transmission. To verify the effectiveness of DCO and determine a proper value for MAC parameters, we conduct experimental simulations under IEEE 802.11n PHY/MAC environments. The simulation results show that the reduced CW_min has the most significant effect on the channel occupancy. The Wi-Fi backscatter devices achieve much higher throughput than the separate cases when two or more configurations are used simultaneously. Moreover, the results exhibit that the use of SIFS between consecutive packets supports reliable burst transmission regardless of the transmission of the legacy Wi-Fi devices in the vicinity. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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4071 KiB

Open AccessArticle

Maximum Efficiency per Torque Control of Permanent-Magnet Synchronous Machines

by Qingbo Guo, Chengming Zhang, Liyi Li, Jiangpeng Zhang and Mingyi Wang

Appl. Sci. 2016, 6(12), 425; https://doi.org/10.3390/app6120425 - 12 Dec 2016

Cited by 17 | Viewed by 6261

Abstract

High-efficiency permanent-magnet synchronous machine (PMSM) drive systems need not only optimally designed motors but also efficiency-oriented control strategies. However, the existing control strategies only focus on partial loss optimization. This paper proposes a novel analytic loss model of PMSM in either sine-wave pulse-width [...] Read more.

High-efficiency permanent-magnet synchronous machine (PMSM) drive systems need not only optimally designed motors but also efficiency-oriented control strategies. However, the existing control strategies only focus on partial loss optimization. This paper proposes a novel analytic loss model of PMSM in either sine-wave pulse-width modulation (SPWM) or space vector pulse width modulation (SVPWM) which can take into account both the fundamental loss and harmonic loss. The fundamental loss is divided into fundamental copper loss and fundamental iron loss which is estimated by the average flux density in the stator tooth and yoke. In addition, the harmonic loss is obtained from the Bertotti iron loss formula by the harmonic voltages of the three-phase inverter in either SPWM or SVPWM which are calculated by double Fourier integral analysis. Based on the analytic loss model, this paper proposes a maximum efficiency per torque (MEPT) control strategy which can minimize the electromagnetic loss of PMSM in the whole operation range. As the loss model of PMSM is too complicated to obtain the analytical solution of optimal loss, a golden section method is applied to achieve the optimal operation point accurately, which can make PMSM work at maximum efficiency. The optimized results between SPWM and SVPWM show that the MEPT in SVPWM has a better effect on the optimization performance. Both the theory analysis and experiment results show that the MEPT control can significantly improve the efficiency performance of the PMSM in each operation condition with a satisfied dynamic performance. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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4240 KiB

Open AccessArticle

Investigation of an Ironless Permanent Magnet Linear Synchronous Motor with Cooling System

by Lu Zhang, Baoquan Kou, Yinxi Jin, Yusheng Chen and Yanjie Liu

Appl. Sci. 2016, 6(12), 422; https://doi.org/10.3390/app6120422 - 10 Dec 2016

Cited by 5 | Viewed by 11872

Abstract

In this paper, a novel ironless linear synchronous motor with a cooling system is proposed. Firstly, the topology of this ironless linear synchronous motor with a cooling system is introduced. Flux density in the cooling system is obtained analytically by the separation of [...] Read more.

In this paper, a novel ironless linear synchronous motor with a cooling system is proposed. Firstly, the topology of this ironless linear synchronous motor with a cooling system is introduced. Flux density in the cooling system is obtained analytically by the separation of variables method according to the boundary conditions. The eddy current braking force induced by the cooling system is calculated and validated by finite element method. Then, the influence of the motor parameters on the eddy current braking force is investigated. At last, a prototype is manufactured and some experiments are carried out with the prototype. The experiment results are validated by finite element analyzed results. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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4360 KiB

Open AccessArticle

Improved ADRC for a Maglev Planar Motor with a Concentric Winding Structure

by Baoquan Kou, Feng Xing, Chaoning Zhang, Lu Zhang, Yiheng Zhou and Tiecheng Wang

Appl. Sci. 2016, 6(12), 419; https://doi.org/10.3390/app6120419 - 10 Dec 2016

Cited by 9 | Viewed by 6196

Abstract

In the semiconductor industry, positioning accuracy and acceleration are critical parameters. To improve the acceleration speed of a motor, this paper proposes the moving-coil maglev planar motor with a concentric winding structure. The coordinate system has been built for the multiple degrees of [...] Read more.

In the semiconductor industry, positioning accuracy and acceleration are critical parameters. To improve the acceleration speed of a motor, this paper proposes the moving-coil maglev planar motor with a concentric winding structure. The coordinate system has been built for the multiple degrees of freedom movement system. The Lorenz force method has been applied to solve its electromagnetic model. The real-time solving of the generalized inverse matrix of factors can realize the decoupling of the winding current. When the maglev height changes, the electromagnetic force and torque decreases exponentially with the increase of the air gap. To decrease the influence on control system performance by the internal model change and the external disturbance, this paper proposes an improved active disturbance rejection control (ADRC) to design the controller. This new controller overcomes the jitter phenomenon due to the turning point for the traditional ADRC, thus it is more suitable for the maglev control system. The comparison between ADRC and the improved ADRC has been conducted, the result of which shows the improved ADRC has greater robustness. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3469 KiB

Open AccessArticle

Seismic Responses of a Cable-Stayed Bridge with Consideration of Uniform Temperature Load

by Junjun Guo, Jian Zhong, Xinzhi Dang and Wancheng Yuan

Appl. Sci. 2016, 6(12), 408; https://doi.org/10.3390/app6120408 - 9 Dec 2016

Cited by 5 | Viewed by 5562

Abstract

The effects of temperature load on the dynamic responses of cable-stayed bridges have attracted the attention of researchers in recent years. However, these investigations mainly focus on the influence of temperature on the dynamic characteristics of structures, such as vibration mode and frequency. [...] Read more.

The effects of temperature load on the dynamic responses of cable-stayed bridges have attracted the attention of researchers in recent years. However, these investigations mainly focus on the influence of temperature on the dynamic characteristics of structures, such as vibration mode and frequency. This paper discusses the effects of uniform temperature changes on the seismic responses of a cable-stayed bridge. A three dimensional finite element model of a cable-stayed bridge using OpenSees is established for nonlinear time history analysis, and uniform temperature load is applied to the prototype bridge before the conducting of seismic excitation. Three ground motion records are selected from the PEER strong motion database based on the design spectrum. Case studies are then performed considering the varying temperature and the connections between the deck and pylons of the bridge. The result shows that the seismic responses of the bridge are significantly increased with the consideration of temperature load. Meanwhile, the types between the deck and pylon also have notable impacts on the seismic responses of the bridge with and without temperature changes. This research could provide a reference for designers during the design phase of cable-stayed brides. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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728 KiB

Open AccessArticle

A Novel Mobile Communications Authentication Scheme with Roaming Service and User Anonymity

by Kai Chain, Wen-Chung Kuo and Jiin-Chiou Cheng

Appl. Sci. 2016, 6(12), 393; https://doi.org/10.3390/app6120393 - 30 Nov 2016

Cited by 3 | Viewed by 3527

Abstract

Many novel, effective, and efficient applications and networking services are being developed for the Social Internet of Things. Recently, Li proposed a more secure and efficient authentication scheme with roaming service and user anonymity for mobile communications. The security analysis and discussion of [...] Read more.

Many novel, effective, and efficient applications and networking services are being developed for the Social Internet of Things. Recently, Li proposed a more secure and efficient authentication scheme with roaming service and user anonymity for mobile communications. The security analysis and discussion of the agreement phase is sufficiently safe; however, an attacker can intercept the identity of a mobile user’s home agent in the authentication phase. By using this information, the attacker can mount distributed denial-of-service attacks in the roaming phase through replay attacks targeting the network’s foreign agent and mobile user’s home agent by using their corresponding session keys. Li’s method also has some shortcomings regarding anonymity that we aim to address. To overcome these issues, this study proposes an elliptic curve–based wireless roaming anonymous login method for the authentication phase. The problems faced in the roaming phase are resolved, and this approach provides balanced session key computation between senders and receivers. Burrows-Abadi-Needham logic (BAN-logic) is used to verify the security of the proposed scheme. The proposed scheme affords good security, efficiency, and integrity and maintains anonymity. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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1523 KiB

Open AccessArticle

A Study on the Design of the Top Flange of a Modular T-Girder Bridge Using the Limit State Design Method

by Jongho Park, Jinwoong Choi, Hongmyung Lee, Sun-Kyu Park and Sungnam Hong

Appl. Sci. 2016, 6(12), 381; https://doi.org/10.3390/app6120381 - 25 Nov 2016

Cited by 2 | Viewed by 5427

Abstract

This study involved applying a design code change on a modular bridge design. The top flange of a modular T-girder bridge was examined by the Korean Highway Bridge Design Code Limit State Design (2015) and was compared with the Korean Highway Bridge Design [...] Read more.

This study involved applying a design code change on a modular bridge design. The top flange of a modular T-girder bridge was examined by the Korean Highway Bridge Design Code Limit State Design (2015) and was compared with the Korean Highway Bridge Design Code (2010) in terms of the stability under the bending moment. In addition, the cross-sectional height and reinforcement amount were re-designed to obtain a safety factor similar to the original code. The reinforcement arrangement and development of the transverse joints were examined in the section considered. The result indicated that the application of the Korean Highway Bridge Design Code Limit State Design (2015) increased the bending moment safety factor and decreased the width of the transverse joints. The results of the re-design with respect to a safety factor similar to that in the Korean Highway Bridge Design Code (2010) indicated that it was possible to reduce the cross-sectional height and reinforcement amount. Furthermore, based on the obtained section, the results revealed that the width of the transverse joints could be reduced by changing the arrangement of lap splices from the straight bar to the loop. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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6971 KiB

Open AccessArticle

Digital Controller Design Based on Active Damping Method of Capacitor Current Feedback for Auxiliary Resonant Snubber Inverter with LC Filter

by Hailin Zhang, Baoquan Kou, Lu Zhang and Yinxi Jin

Appl. Sci. 2016, 6(11), 377; https://doi.org/10.3390/app6110377 - 22 Nov 2016

Cited by 5 | Viewed by 6625

Abstract

In some high-performance applications, an LC filter must be added to the auxiliary resonant snubber inverter (ARSI) to reduce the output current ripple. However, resonance occurs due to the additional LC filter, which makes the traditional closed-loop control not suitable to be used [...] Read more.

In some high-performance applications, an LC filter must be added to the auxiliary resonant snubber inverter (ARSI) to reduce the output current ripple. However, resonance occurs due to the additional LC filter, which makes the traditional closed-loop control not suitable to be used directly. Therefore, this paper presents a double-loop digital control based on the active damping method of capacitor current feedback to stabilize the system. Most of the studies on active damping methods are focused on the grid in consideration of zero resistance. However, the load resistance should not be neglected in the drive system. Therefore, the load resistance and digital control delays are considered in this paper. Moreover, an improved loading method is proposed to improve the duty ratio range. In order to verify the effectiveness of the controller, a prototype was developed. The simulation and experimental results demonstrate that soft-switching can be realized for the entire load range. The maximum duty ratio is improved by 0.01 by using the proposed loading method. The resonance can be eliminated by using the proposed control method. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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15451 KiB

Open AccessArticle

Land Cover Classification Using a KOMPSAT-3A Multi-Spectral Satellite Image

by Tri Dev Acharya, In Tae Yang and Dong Ha Lee

Appl. Sci. 2016, 6(11), 371; https://doi.org/10.3390/app6110371 - 21 Nov 2016

Cited by 17 | Viewed by 6845

Abstract

New sets of satellite sensors are frequently being added to the constellation of remote sensing satellites. These new sets offer improved specification to collect imagery on-demand over specific locations and for specific purposes. The Korea Multi-Purpose Satellite (KOMPSAT) series of satellites is a [...] Read more.

New sets of satellite sensors are frequently being added to the constellation of remote sensing satellites. These new sets offer improved specification to collect imagery on-demand over specific locations and for specific purposes. The Korea Multi-Purpose Satellite (KOMPSAT) series of satellites is a multi-purposed satellite system developed by Korea Aerospace Research Institute (KARI). The recent satellite of the KOMPSAT series, KOMPSAT-3A, demonstrates high resolution multi-spectral imagery with infrared and high resolution electro-optical bands for geographical information systems applications in environmental, agricultural and oceanographic sciences as well as natural disasters. In this study, land cover classification of multispectral data was performed using four supervised classification methods: Mahalanobis Distance (MahD), Minimum Distance (MinD), Maximum Likelihood (ML) and Support Vector Machine (SVM), using a KOMPSAT-3A multi-spectral imagery with 2.2 m spatial resolution. The study area for this study was selected from southwestern region of South Korea, around Buan city. The training data for supervised classification was carefully selected by visual interpretation of KOMPSAT-3A imagery and field investigation. After classification, the results were then analyzed for the validation of classification accuracy by comparison with those of field investigation. For the validation, we calculated the User’s Accuracy (UA), Producer’s Accuracy (PA), Overall Accuracy (OA) and Kappa statistics from the error matrix to check the classification accuracy for each class obtained individually from different methods. Finally, the comparative analysis was done for the study area for various results of land cover classification using a KOMPSAT-3A multi-spectral imagery. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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2053 KiB

Open AccessArticle

TRAP: A Three-Way Handshake Server for TCP Connection Establishment

by Fu-Hau Hsu, Yan-Ling Hwang, Cheng-Yu Tsai, Wei-Tai Cai, Chia-Hao Lee and KaiWei Chang

Appl. Sci. 2016, 6(11), 358; https://doi.org/10.3390/app6110358 - 16 Nov 2016

Cited by 16 | Viewed by 32770

Abstract

Distributed denial of service attacks have become more and more frequent nowadays. In 2013, a massive distributed denial of service (DDoS) attack was launched against Spamhaus causing the service to shut down. In this paper, we present a three-way handshaking server for Transmission [...] Read more.

Distributed denial of service attacks have become more and more frequent nowadays. In 2013, a massive distributed denial of service (DDoS) attack was launched against Spamhaus causing the service to shut down. In this paper, we present a three-way handshaking server for Transmission Control Protocol (TCP) connection redirection utilizing TCP header options. When a legitimate client attempted to connect to a server undergoing an SYN-flood DDoS attack, it will try to initiate a three-way handshake. After it has successfully established a connection, the server will reply with a reset (RST) packet, in which a new server address and a secret is embedded. The client can, thus, connect to the new server that only accepts SYN packets with the corrected secret using the supplied secret. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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557 KiB

Open AccessArticle

Energy-Efficient On–Off Power Control of Femto-Cell Base Stations for Cooperative Cellular Networks

by Woongsup Lee and Bang Chul Jung

Appl. Sci. 2016, 6(11), 356; https://doi.org/10.3390/app6110356 - 16 Nov 2016

Cited by 2 | Viewed by 4164

Abstract

Improving energy efficiency (EE) of mobile communication systems (MCSs) has been considered a key aim in recent years, and has been the subject of intense research interest. One of the simplest yet most powerful ways to increase the EE is to turn off [...] Read more.

Improving energy efficiency (EE) of mobile communication systems (MCSs) has been considered a key aim in recent years, and has been the subject of intense research interest. One of the simplest yet most powerful ways to increase the EE is to turn off redundant communication entities whose operation does not greatly affect the overall performance of the MCS. In this paper, we propose a novel on–off power control scheme for femto-cell base stations (FBSs) considering cooperative transmission in which multiple FBSs collaborate on the same data transmission. In the proposed scheme, the operation of the redundant FBSs is halted in an adaptive manner. For the proper determination of redundant FBSs with low computational complexity, we propose using the level of contribution (LOC), which specifies the importance of a given FBS in the cooperative transmission. Redundant FBSs are chosen based on their LOC value, and these FBSs are turned off in order to reduce the power consumption of MCSs while minimizing the degradation of the overall throughput of cooperative transmissions. The performance of the proposed scheme is verified through extensive simulations, which shows that near-optimal performance can be achieved without excessive computations. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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5037 KiB

Open AccessArticle

Analysis and Compensation of Dead-Time Effect of a ZVT PWM Inverter Considering the Rise- and Fall-Times

by Hailin Zhang, Baoquan Kou, Lu Zhang and He Zhang

Appl. Sci. 2016, 6(11), 344; https://doi.org/10.3390/app6110344 - 9 Nov 2016

Cited by 10 | Viewed by 7945

Abstract

The dead-time effect, as an intrinsic problem of the converters based on the half-bridge unit, leads to distortions in the converter output. Although several dead-time effect compensation or elimination methods have been proposed, they cannot fully remove the dead-time effect of blanking delay [...] Read more.

The dead-time effect, as an intrinsic problem of the converters based on the half-bridge unit, leads to distortions in the converter output. Although several dead-time effect compensation or elimination methods have been proposed, they cannot fully remove the dead-time effect of blanking delay error, because the output current polarity is difficult detect accurately. This paper utilizes the zero-voltage-switching (ZVT) technique to eliminate the blanking delay error, which is the main drawback of the hard-switching inverter, although the technique initially aims to improve the efficiency. A typical ZVT inverter—the auxiliary resonant snubber inverter (ARSI) is analyzed. The blanking delay error is completely eliminated in the ARSI. Another error source caused by the finite rise- and fall-times of the voltage is analyzed, which was not considered in the hard-switching inverter. A compensation method based on the voltage error estimation is proposed to compensate the rise- and fall-error. A prototype was developed to verify the effectiveness of the proposed control. Both the simulation and experimental results demonstrate that the qualities of the output current and voltage in the ARSI are better than that in the hard-switching inverter due to the elimination of the blanking delay error. The total harmonic distortion (THD) of the output is further reduced by using the proposed compensation method in the ARSI. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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Open AccessArticle

The Effect of Fuel Mass Fraction on the Combustion and Fluid Flow in a Sulfur Recovery Unit Thermal Reactor

by Chun-Lang Yeh

Appl. Sci. 2016, 6(11), 331; https://doi.org/10.3390/app6110331 - 2 Nov 2016

Cited by 10 | Viewed by 5538

Abstract

Sulfur recovery unit (SRU) thermal reactors are negatively affected by high temperature operation. In this paper, the effect of the fuel mass fraction on the combustion and fluid flow in a SRU thermal reactor is investigated numerically. Practical operating conditions for a petrochemical [...] Read more.

Sulfur recovery unit (SRU) thermal reactors are negatively affected by high temperature operation. In this paper, the effect of the fuel mass fraction on the combustion and fluid flow in a SRU thermal reactor is investigated numerically. Practical operating conditions for a petrochemical corporation in Taiwan are used as the design conditions for the discussion. The simulation results show that the present design condition is a fuel-rich (or air-lean) condition and gives acceptable sulfur recovery, hydrogen sulfide (H₂S) destruction, sulfur dioxide (SO₂) emissions and thermal reactor temperature for an oxygen-normal operation. However, for an oxygen-rich operation, the local maximum temperature exceeds the suggested maximum service temperature, although the average temperature is acceptable. The high temperature region must be inspected very carefully during the annual maintenance period if there are oxygen-rich operations. If the fuel mass fraction to the zone ahead of the choke ring (zone 1) is 0.0625 or 0.125, the average temperature in the zone behind the choke ring (zone 2) is higher than the zone 1 average temperature, which can damage the downstream heat exchanger tubes. If the zone 1 fuel mass fraction is reduced to ensure a lower zone 1 temperature, the temperature in zone 2 and the heat exchanger section must be monitored closely and the zone 2 wall and heat exchanger tubes must be inspected very carefully during the annual maintenance period. To determine a suitable fuel mass fraction for operation, a detailed numerical simulation should be performed first to find the stoichiometric fuel mass fraction which produces the most complete combustion and the highest temperature. This stoichiometric fuel mass fraction should be avoided because the high temperature could damage the zone 1 corner or the choke ring. A higher fuel mass fraction (i.e., fuel-rich or air-lean condition) is more suitable because it can avoid deteriorations of both zone 1 and heat exchanger tubes. Although a lower fuel mass fraction (i.e., fuel-lean or air-rich condition) can avoid deterioration of zone 1, the heat exchanger tubes may be damaged. This paper provides a guideline for adjusting the fuel mass fraction to reduce the high temperature inside the thermal reactor and to ensure an acceptable sulfur recovery. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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1656 KiB

Open AccessArticle

Low-Cost Temperature Logger for a Polymerase Chain Reaction Thermal Cycler

by Chan-Young Park, Jae-Hyeon Cho, Yu-Seop Kim, Hye-Jeong Song and Jong-Dae Kim

Appl. Sci. 2016, 6(11), 328; https://doi.org/10.3390/app6110328 - 31 Oct 2016

Cited by 2 | Viewed by 5998

Abstract

Polymerase chain reaction (PCR) is a method of amplifying DNA which is normally carried out with a thermal cycler. To obtain more accurate and reliable PCR results, the temperature change within the chamber of the thermal cycler needs to be verified and calibrated [...] Read more.

Polymerase chain reaction (PCR) is a method of amplifying DNA which is normally carried out with a thermal cycler. To obtain more accurate and reliable PCR results, the temperature change within the chamber of the thermal cycler needs to be verified and calibrated regularly. Commercially available temperature loggers commonly used for temperature verification tests usually require a graphical user interface (GUI) attached to the logger for convenience and straightforward understanding of the device. In this study, a host-local architecture for the temperature logger that significantly reduces the development time and cost is proposed. Employing standard computing devices as the host gives better development environment and user-friendly GUI. This paper presents the hardware and software design of the host-local temperature logger, and demonstrates the use of the local temperature logger connected to a personal computer with a Windows operating system. The probe design, thermistor resistance measurement, temperature filtering, and temperature calibration is described in detail. The thermistor self-heating problem was investigated in particular to determine the reference resistor that was serially connected to the thermistor. The temperature accuracy and temporal precision of the proposed system was 0.1 K. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3676 KiB

Open AccessArticle

Structural Performance of Steel Pile Caps Strengthened with Perfobond Shear Connectors under Lateral Loading

by Young-Ho Kim, Jae-Yoon Kang, Sang-Ho Kim and Dae-Jin Kim

Appl. Sci. 2016, 6(11), 317; https://doi.org/10.3390/app6110317 - 26 Oct 2016

Cited by 13 | Viewed by 10392

Abstract

The conventional strengthening strategy on the connection between the steel pile cap and reinforced concrete footing requires a series of complicated processes such as the distribution of reinforcing bars, their anchorage into concrete, and the usage of shear keys. This study investigates the [...] Read more.

The conventional strengthening strategy on the connection between the steel pile cap and reinforced concrete footing requires a series of complicated processes such as the distribution of reinforcing bars, their anchorage into concrete, and the usage of shear keys. This study investigates the structural performance of steel pile caps strengthened with newly proposed perfobond shear connectors subjected to lateral loading. Test parameters include the type of perfobond shear connectors, infilled concrete depth, and the number of L-shaped steel plates. The applied load versus deformation curve is plotted for all specimens, and their failure modes are identified. The effects of the test parameters on the peak load are examined in this work. From the results of this study, it can be confirmed that the proposed perfobond shear connector can be utilized as an alternative to the conventional steel pile cap strengthening method using steel rebars. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3578 KiB

Open AccessArticle

Tracking a Driver’s Face against Extreme Head Poses and Inference of Drowsiness Using a Hidden Markov Model

by In-Ho Choi, Chan-Hee Jeong and Yong-Guk Kim

Appl. Sci. 2016, 6(5), 137; https://doi.org/10.3390/app6050137 - 7 May 2016

Cited by 34 | Viewed by 8950

Abstract

This study presents a new method to track driver’s facial states, such as head pose and eye-blinking in the real-time basis. Since a driver in the natural driving condition moves his head in diverse ways and his face is often occluded by his [...] Read more.

This study presents a new method to track driver’s facial states, such as head pose and eye-blinking in the real-time basis. Since a driver in the natural driving condition moves his head in diverse ways and his face is often occluded by his hand or the wheel, it should be a great challenge for the standard face models. Among many, Active Appearance Model (AAM), and Active Shape Model (ASM) are two favored face models. We have extended Discriminative Bayesian ASM by incorporating the extreme pose cases, called it Pose Extended—Active Shape model (PE-ASM). Two face databases (DB) are used for the comparison purpose: one is the Boston University face DB and the other is our custom-made driving DB. Our evaluation indicates that PE-ASM outperforms ASM and AAM in terms of the face fitting against extreme poses. Using this model, we can estimate the driver’s head pose, as well as eye-blinking, by adding respective processes. Two HMMs are trained to model temporal behaviors of these two facial features, and consequently the system can make inference by enumerating these HMM states whether the driver is drowsy or not. Result suggests that it can be used as a driver drowsiness detector in the commercial car where the visual conditions are very diverse and often tough to deal with. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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9383 KiB

Open AccessArticle

A Case Study on the Rehabilitation of a Fire-Damaged Structure

by Taehun Ha, Jeongwon Ko, Sangho Lee, Seonwoong Kim, Jieun Jung and Dae-Jin Kim

Appl. Sci. 2016, 6(5), 126; https://doi.org/10.3390/app6050126 - 2 May 2016

Cited by 23 | Viewed by 5961

Abstract

This paper presents a case study on the rehabilitation of a fire-damaged structure and describes the results of a site investigation and tests, leading to a plan for the rehabilitation of the structure. The fire took place in the main control room of [...] Read more.

This paper presents a case study on the rehabilitation of a fire-damaged structure and describes the results of a site investigation and tests, leading to a plan for the rehabilitation of the structure. The fire took place in the main control room of a thermal power plant and lasted about three hours until it was finally extinguished. To set up a rehabilitation plan for the damaged structure, a visual inspection of the damaged condition was first carried out, which was followed by analysis and on-site material tests indicating the degree of neutralization progress in the remaining structure. Specimens of damaged concrete and reinforcing bars were sampled and tested for their residual strengths. As a conclusion, two methods of rehabilitation were suggested considering the current condition of the structure and the sequence of construction. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3749 KiB

Open AccessArticle

Application of a New Anchorage towards the Flexural Strengthening of RC Rectangular Beams with External Steel Tendons

by Sungnam Hong, Dooyong Cho and Sun-Kyu Park

Appl. Sci. 2016, 6(5), 119; https://doi.org/10.3390/app6050119 - 25 Apr 2016

Cited by 3 | Viewed by 9313

Abstract

To strengthen concrete beams, a new anchorage was proposed, and its performance was evaluated in this study. Seven concrete beams were manufactured and flexurally loaded with displacement control up to the failure point. As important test variables, the anchorage type (new/conventional) and the [...] Read more.

To strengthen concrete beams, a new anchorage was proposed, and its performance was evaluated in this study. Seven concrete beams were manufactured and flexurally loaded with displacement control up to the failure point. As important test variables, the anchorage type (new/conventional) and the prestress levels in the steel rebar (0, 50, and 100 kN) were selected. To investigate the strengthening effects based on these test variables, the deflection, strain, and failure mode were recorded, and then the load, ductility index, and energy ratio were analyzed. Test results showed that the newly proposed end anchorage had better strengthening effects and a greater inelastic energy than the conventional end anchorages. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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1845 KiB

Open AccessArticle

Dynamically Determining the Toll Plaza Capacity by Monitoring Approaching Traffic Conditions in Real-Time

by Cheolsun Kim, Dong-Kyu Kim, Seung-Young Kho, Seungmo Kang and Koohong Chung

Appl. Sci. 2016, 6(3), 87; https://doi.org/10.3390/app6030087 - 18 Mar 2016

Cited by 13 | Viewed by 5455

Abstract

This study presents an analytical method for dynamically adjusting toll plaza capacity to cope with a sudden shift in demand. The proposed method uses a proxy measure developed using discharge rate observed at toll plazas and segment travel times measured by probe vehicles. [...] Read more.

This study presents an analytical method for dynamically adjusting toll plaza capacity to cope with a sudden shift in demand. The proposed method uses a proxy measure developed using discharge rate observed at toll plazas and segment travel times measured by probe vehicles. The effectiveness of the method has been evaluated by analyzing the empirical data obtained from toll plazas in the San Francisco Bay Area before and after toll plaza capacity changed. Findings indicate that the estimated number of vehicles stored near the upstream of toll plaza based on discharge rate and their travel times can be used as a proxy measure for predicting the effect of changes in toll plaza capacity. The proposed model can aid government agencies to dynamically adjust the toll plaza capacity in response to a sudden shift in demand due to various situations of failure. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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3418 KiB

Open AccessArticle

Polypropylene/Graphene and Polypropylene/Carbon Fiber Conductive Composites: Mechanical, Crystallization and Electromagnetic Properties

by Chien-Lin Huang, Ching-Wen Lou, Chi-Fan Liu, Chen-Hung Huang, Xiao-Min Song and Jia-Horng Lin

Appl. Sci. 2015, 5(4), 1196-1210; https://doi.org/10.3390/app5041196 - 13 Nov 2015

Cited by 83 | Viewed by 7926

Abstract

This study aims to examine the properties of composites that different carbon materials with different measurements can reinforce. Using a melt compounding method, this study combines polypropylene (PP) and graphene nano-sheets (GNs) or carbon fiber (CF) to make PP/GNs and PP/CF conductive composites, [...] Read more.

This study aims to examine the properties of composites that different carbon materials with different measurements can reinforce. Using a melt compounding method, this study combines polypropylene (PP) and graphene nano-sheets (GNs) or carbon fiber (CF) to make PP/GNs and PP/CF conductive composites, respectively. The DSC results and optical microscopic observation show that both GNs and CF enable PP to crystalize at a high temperature. The tensile modulus of PP/GNs and PP/CF conductive composites remarkably increases as a result of the increasing content of conductive fillers. The tensile strength of the PP/GNs conductive composites is inversely proportional to the loading level of GNs. Containing 20 wt% of GNs, the PP/GNs conductive composites have an optimal conductivity of 0.36 S/m and an optimal EMI SE of 13 dB. PP/CF conductive composites have an optimal conductivity of 10⁻⁶ S/m when composed of no less than 3 wt% of CF, and an optimal EMI SE of 25 dB when composed of 20 wt% of CF. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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5547 KiB

Open AccessArticle

Multi-Bit Data Hiding Scheme for Compressing Secret Messages

by Wen-Chung Kuo, Shao-Hung Kuo and Lih-Chyau Wuu

Appl. Sci. 2015, 5(4), 1033-1049; https://doi.org/10.3390/app5041033 - 4 Nov 2015

Cited by 10 | Viewed by 4567

Abstract

The goal of data hiding techniques usually considers two issues, embedding capacity and image quality. Consequently, in order to achieve high embedding capacity and good image quality, a data hiding scheme combining run-length encoding (RLE) with multi-bit embedding is proposed in this paper. [...] Read more.

The goal of data hiding techniques usually considers two issues, embedding capacity and image quality. Consequently, in order to achieve high embedding capacity and good image quality, a data hiding scheme combining run-length encoding (RLE) with multi-bit embedding is proposed in this paper. This work has three major contributions. First, the embedding capacity is increased 62% because the secret message is compressed before embedding into the cover image. Secondly, the proposed scheme keeps the multi-bit generalized exploiting modification direction (MGEMD) characteristics, which are effective to reduce modified pixels in the cover image and to maintain good stego image quality. Finally, the proposed scheme can prevent modern steganalysis methods, such as RS steganalysis and SPAM (subtractive pixel adjacency matrix), and is compared to MiPOD (minimizing the power of the optimal detector) scheme. From our simulation results and security discussions, we have the following results: First, there are no perceivable differences between the cover images and stego images from human inspection. For example, the average PSNR of stego images is about 44.61 dB when the secret message (80,000 bits) is embedded for test cover images (such as airplane, baboon, Lena) of size 512×512. Secondly, Appl. Sci. 2015, 5 1034 on average, 222,087 pixels were not modified after embedding for the cover image. That is to say, 12% less pixels are modified as compared to the MGEMD method. From the performance discussions, the proposed scheme achieves high embedding capacity and good image quality, but also maintains stego image security. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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803 KiB

Open AccessArticle

Study on Sintering System of Calcium Barium Sulphoaluminate by XRD Quantitative Analysis

by Jun Chang, Xiaopeng Shang and Jiuye Zhao

Appl. Sci. 2015, 5(4), 989-997; https://doi.org/10.3390/app5040989 - 2 Nov 2015

Cited by 14 | Viewed by 4800

Abstract

Calcium barium sulphoaluminate (CBSA), derived from calcium sulphoaluminate (CSA), has excellent cementitious properties. In this study, the sintering system of CBSA with a theoretical stoichiometric Ca₃BaAl₆SO₁₆ was investigated. Rietveld refinement was performed using TOPAS 4.2 software to quantitatively [...] Read more.

Calcium barium sulphoaluminate (CBSA), derived from calcium sulphoaluminate (CSA), has excellent cementitious properties. In this study, the sintering system of CBSA with a theoretical stoichiometric Ca₃BaAl₆SO₁₆ was investigated. Rietveld refinement was performed using TOPAS 4.2 software to quantitatively calculate the content of CBSA and the actual ionic site occupancy of Ba²⁺. The results indicate that the content of Ca_4−xBa_xAl₆SO₁₆ increases with increasing sintering temperature in the 1200–1400 °C ranges. When sintered at 1400 °C for 180 min, the content of CBSA reaches 88.4%. However, CBSA begins to decompose at 1440 °C, after which the content decreases. The replacement rate of Ba²⁺ was also enlarged by increasing sintering temperature and prolonged sintering time. Sintering at 1400 °C for 180 min is considered as the optimum when replacement rate of Ba²⁺ and the content of CBSA were taken into account. Ca_3.2Ba_0.8Al₆SO₁₆ with a content of 88.4% was synthesized. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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781 KiB

Open AccessArticle

Using a Random Secret Pre-Distribution Scheme to Implement Message Authentication in VANETs

by Alan Dahgwo Yein, Yu-Hsiu Huang, Chih-Hsueh Lin, Wen-Shyong Hsieh, Chung-Nan Lee and Zhong-Ting Luo

Appl. Sci. 2015, 5(4), 973-988; https://doi.org/10.3390/app5040973 - 30 Oct 2015

Cited by 7 | Viewed by 4082

Abstract

In recent years, the development of the Intelligent Transportation System (ITS) has increased the popularity of vehicular ad hoc networks (VANET). A VANET is designed to enable vehicles to exchange information about traffic or vehicle conditions to help other vehicles avoid traffic accidents [...] Read more.

In recent years, the development of the Intelligent Transportation System (ITS) has increased the popularity of vehicular ad hoc networks (VANET). A VANET is designed to enable vehicles to exchange information about traffic or vehicle conditions to help other vehicles avoid traffic accidents or traffic jams. To resist malicious attacks, all vehicles must be anonymous and their routings must be untraceable, but still verifiable. The vehicles must trust each other and communicate confidentially. In a VANET, Road Side Units (RSU) are installed on traffic signs or streetlights to help vehicles maintain anonymity, to authenticate messages, or to support confidentiality. However, the coverage of an RSU is limited and the cost of widespread installation is high. RSU installations are incremental, so messages must be authenticated using dense RSUs or sparse RSUs. In this paper, the concept of random key pre-distribution that is used in Wireless Sensor Networks (WSN) is modified to random secret pre-distribution (RSP), which integrates identity-based cryptography (IBC) to produce a message authentication scheme for VANETs in a sparse RSU environment. In the proposed scheme, vehicles follow a process to determine a common secret, allowing them to authenticate each other and obtain the pairing value as a key for use in message authentication and private communication. Evaluation results show that the proposed scheme outperforms related schemes. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

2374 KiB

Open AccessArticle

Fabrication and Simulation of Self-Focusing Field Emission X-ray Tubes

by Kevin Cheng, Yi-Ping Chou, Meng-Jey Youh, Yih-Ming Liu, Ming-Der Ger, Kung-Hsu Hou and Nen-Wen Pu

Appl. Sci. 2015, 5(4), 942-954; https://doi.org/10.3390/app5040942 - 26 Oct 2015

Cited by 3 | Viewed by 6861

Abstract

A self-focusing field emission (FE) X-ray tube with a large-area cathode design was simulated and fabricated. The designed X-ray tube had a cylindrically symmetric geometry; the diameter of the cathode and the anode was 15 mm, and the cathode-anode distance was 20 mm. [...] Read more.

A self-focusing field emission (FE) X-ray tube with a large-area cathode design was simulated and fabricated. The designed X-ray tube had a cylindrically symmetric geometry; the diameter of the cathode and the anode was 15 mm, and the cathode-anode distance was 20 mm. Owing to the unique cup-shaped design of the cathode, the electron beam emitted from the large-area cathode was focused onto the anode without using magnetic lenses or extra biased electrodes. Carbon nanocoils, which were grown on the bottom of the circular cup-shaped cathode, were used as electron emitters because of their excellent FE properties. A simulation of the electron trajectories for various cup heights revealed that the optimal focal spot size (0.1 mm) was obtained at a cup height of 5 mm when a voltage of 50 kV was applied. To verify this result, an X-ray tube was fabricated and tested. An X-ray photograph of the tested tooth and electric circuits showed good resolution and X-ray intensity. The large cathode area effectively reduces the current density and thereby improves the lifetime of the cathode. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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2482 KiB

Open AccessArticle

Study of Three-Dimensional Image Brightness Loss in Stereoscopy

by Hsing-Cheng Yu, Xie-Hong Tsai, An-Chun Luo, Ming Wu and Sei-Wang Chen

Appl. Sci. 2015, 5(4), 926-941; https://doi.org/10.3390/app5040926 - 21 Oct 2015

Cited by 2 | Viewed by 5198

Abstract

When viewing three-dimensional (3D) images, whether in cinemas or on stereoscopic televisions, viewers experience the same problem of image brightness loss. This study aims to investigate image brightness loss in 3D displays, with the primary aim being to quantify the image brightness degradation [...] Read more.

When viewing three-dimensional (3D) images, whether in cinemas or on stereoscopic televisions, viewers experience the same problem of image brightness loss. This study aims to investigate image brightness loss in 3D displays, with the primary aim being to quantify the image brightness degradation in the 3D mode. A further aim is to determine the image brightness relationship to the corresponding two-dimensional (2D) images in order to adjust the 3D-image brightness values. In addition, the photographic principle is used in this study to measure metering values by capturing 2D and 3D images on television screens. By analyzing these images with statistical product and service solutions (SPSS) software, the image brightness values can be estimated using the statistical regression model, which can also indicate the impact of various environmental factors or hardware on the image brightness. In analysis of the experimental results, comparison of the image brightness between 2D and 3D images indicates 60.8% degradation in the 3D image brightness amplitude. The experimental values, from 52.4% to 69.2%, are within the 95% confidence interval Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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5643 KiB

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Visual Recognition and Its Application to Robot Arm Control

by Jih-Gau Juang, Yi-Ju Tsai and Yang-Wu Fan

Appl. Sci. 2015, 5(4), 851-880; https://doi.org/10.3390/app5040851 - 20 Oct 2015

Cited by 21 | Viewed by 8205

Abstract

This paper presents an application of optical word recognition and fuzzy control to a smartphone automatic test system. The system consists of a robot arm and two webcams. After the words from the control panel that represent commands are recognized by the robot [...] Read more.

This paper presents an application of optical word recognition and fuzzy control to a smartphone automatic test system. The system consists of a robot arm and two webcams. After the words from the control panel that represent commands are recognized by the robot system, the robot arm performs the corresponding actions to test the smartphone. One of the webcams is utilized to capture commands on the screen of the control panel, the other to recognize the words on the screen of the tested smartphone. The method of image processing is based on the Red-Green-Blue (RGB) and Hue-Saturation-Luminance (HSL) color spaces to reduce the influence of light. Fuzzy theory is used in the robot arm’s position control. The Optical Character Recognition (OCR) technique is applied to the word recognition, and the recognition results are then checked by a dictionary process to increase the recognition accuracy. The camera which is used to recognize the tested smartphone also provides object coordinates to the fuzzy controller, then the robot arm moves to the desired positions and presses the desired buttons. The proposed control scheme allows the robot arm to perform different assigned test functions successfully. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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2133 KiB

Open AccessArticle

Design of the Secondary Optical Elements for Concentrated Photovoltaic Units with Fresnel Lenses

by Yi-Cheng Chen and Hung-Wei Chiang

Appl. Sci. 2015, 5(4), 770-786; https://doi.org/10.3390/app5040770 - 12 Oct 2015

Cited by 25 | Viewed by 5461

Abstract

The goal of this presented study was to determine the optimum parameters of secondary optical elements (SOEs) for concentrated photovoltaic (CPV) units with flat Fresnel lenses. Three types of SOEs are under consideration in the design process, including kaleidoscope with equal optical path [...] Read more.

The goal of this presented study was to determine the optimum parameters of secondary optical elements (SOEs) for concentrated photovoltaic (CPV) units with flat Fresnel lenses. Three types of SOEs are under consideration in the design process, including kaleidoscope with equal optical path design (KOD), kaleidoscope with flat top surface (KFTS), and open-truncated tetrahedral pyramid with specular walls (SP). The function of using a SOE with a Fresnel lens in a CPV unit is to achieve high optical efficiency, low sensitivity to the sun tracking error, and improved uniformity of irradiance distribution on the solar cell. Ray tracing technique was developed to simulate the optical characteristics of the CPV unit with various design parameters of each type of SOE. Finally, an optimum KOD-type SOE was determined by parametric design process. The resulting optical performance of the CPV unit with the optimum SOE was evaluated in both single-wavelength and broadband simulation of solar spectrum. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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2870 KiB

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A Study of Optical Design on 9× Zoom Ratio by Using a Compensating Liquid Lens

by Chih-Ta Yen and Jyun-Min Shih

Appl. Sci. 2015, 5(3), 608-621; https://doi.org/10.3390/app5030608 - 21 Sep 2015

Cited by 7 | Viewed by 8630

Abstract

This paper proposes using a liquid lens as a compensating lens and applying intermediate optics to achieve a 9× zoom ratio. The droplet shape and location of the liquid lens can be adjusted reversibly, enabling the focal length and position of the lens [...] Read more.

This paper proposes using a liquid lens as a compensating lens and applying intermediate optics to achieve a 9× zoom ratio. The droplet shape and location of the liquid lens can be adjusted reversibly, enabling the focal length and position of the lens to be tuned by varying the voltage applied to a set of electrodes. Therefore, liquid lenses can replace complex lenses to reduce the total length of optomechanical systems. The CODE V built-in optimization method was used to determine the optimal liquid lens parameters at various zoom ratios. Several general optical aberrations were considered. Compared with a standard intermediate optics system featuring 9× zoom and no compensating lens, the proposed lens improved the Petzval surface curvature (PTZ) and modulation transfer function (MTF). Simulation results revealed that the PTZ decreased 10.92% and the MTF increased 3988% in 40 1p/mm. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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Modeling and Simulation of IGCC Considering Pressure and Flow Distribution of Gasifier

by Di Huang, Huisheng Zhang, Shilie Weng and Ming Su

Appl. Sci. 2016, 6(10), 292; https://doi.org/10.3390/app6100292 - 20 Oct 2016

Cited by 6 | Viewed by 5526

Abstract

The integrated gasification combined cycle (IGCC) is a power generation technology which combines clean coal technology with a combined cycle. The system modeling is significant for design, operation and maintenance of the IGCC power plant. However, the previous IGCC modeling methods only contained [...] Read more.

The integrated gasification combined cycle (IGCC) is a power generation technology which combines clean coal technology with a combined cycle. The system modeling is significant for design, operation and maintenance of the IGCC power plant. However, the previous IGCC modeling methods only contained a simplified compartment gasifier model, which is useful to consider the heat transfer and chemical reaction inside the gasifier, but cannot analyze the pressure and flow distribution. In order to obtain a more accurate model of IGCC system, the volume-resistance technique and modular modeling method are utilized in this paper. The new model can depict the dynamic response and distribution characteristics of the gasifier, as well as their influence on the IGCC system. The simulation result of the gasifier and IGCC system shows an obvious delay after considering pressure and flow distribution. Therefore, the proposed IGCC system model can obtain a more reliable result when considering the distribution characteristics of the gasifier. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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