Applied Mechanics and Materials Vols. 284-287

Abstract: An algorithm for robot mapping is proposed in this paper using the method of speeded-up robust features (SURF). Since SURFs are scale- and orientation-invariant features, they have higher repeatability than that of the features obtained by other detection methods. Even in the cases of using moving camera, the SURF method can robustly extract the features from image sequences. Therefore, SURFs are suitable to be utilized as the map features in visual simultaneous localization and mapping (SLAM). In this article, the procedures of detection and matching of the SURF method are modified to improve the image processing speed and feature recognition rate. The sparse representation of SURF is also utilized to describe the environmental map in SLAM tasks. The purpose is to reduce the computation complexity in state estimation using extended Kalman filter (EKF). The EKF SLAM with SURF-based map is developed and implemented on a binocular vision system. The integrated system has been successfully validated to fulfill the basic capabilities of SLAM system.

Abstract: With advanced micro-electromechanical technology, the development of small-size, low-cost, and low-power sensors that possess sensing, signal processing and wireless communication capabilities is becoming popular than ever. To achieve the energy efficiency in the wireless sensor networks, LEACH has been proposed as a routing protocol, composing of a few clusters, each of which consists of member nodes that sense the data, and head nodes that deliver the collected data from member nodes to a sink node. When wireless link error occurs, LEACH may miss some messages because of only one cluster head. As our proposed scheme manages two cluster heads for each cluster, there should be higher probabilities for messages to reach the sink node. Simulation results show that our proposed algorithm provides more robust than LEACH when wireless link error occurs.

Abstract: The reliability of the distributed system has been an important topic of research. Agreement problem plays a key role in the design of reliable distributed system, which allow the correct nodes to agree on a common value, have been brought up to aid the reliable execution of tasks. However, most existing agreement protocols are no longer practical in the wireless sensor network. In this paper, agreement problem is reexamined in a cluster-based wireless sensor network (CWSN). The purposed protocol can make all correct nodes reaching agreement with two rounds of message exchange and tolerant the maximal number of allowable fallible components.

Abstract: Detection of pH value plays an important role in many fields; the precise measurement of pH value is very useful in Living systems, Chemistry and Biochemistry. The purpose of this paper is to measure pH value in solution by using Corrugated Long Period Fiber Grating (CLPFG). The CLPFG element is highly sensitive to refractive index changes, and with appropriate design geometry; a variety of target molecules can then be detected. Optical fiber Corrugated Long Period Gratings are designed to act as spectral loss elements that couple with a discrete wavelength out of the optical fiber as a function of the surrounding refractive index. By applying special coating that change refractive index with absorption of target molecules to the CLPFG surface, it became a transducer for chemical measurement. In this paper, it has shown the incorporation of Polyvinyl Alcohol and Polycyclic Acid (PVA-PAA) with Corrugated Long Period Gratings for the development of a fiber optic-based pH sensor with the detection of pH range from 3 to 6. Optical fiber-based pH sensors offer numerous advantages in wastewater monitoring, remote blood diagnostics, bioremediation, as well as chemical and food processing.

Abstract: In this paper, a new type small-angle sensor based on multiple total internal reflections and attenuated total reflections in heterodyne interferometry is presented. The small-angle sensor is designed as a reflective elongated prism that is made of BK7 glass. The shorter-side surface of the reflective elongated prism was coated with 2nm Ti-film and 45.5nm Au-film, but the longer-side surface of that was not coated with metal films. With the new type small-angle sensor, the small rotation angle can be obtained only by measuring the phase difference between the p-and s-polarization lights due to the multiple attenuated total-internal reflections (MATRs) and total-internal reflections (TIRs) effects. Its angular resolution can reach 0.000000295 radian at least. The new type small-angle sensor has some merits, e.g., high resolution, high sensitivity, stability, and in real-time test, etc.

Abstract: The algorithm presented in this paper takes at least two images taken by an ordinary digital camera, computes camera parameters and outputs scene geometric information. The method takes at least one right-angle triangle in the scene, install a local coordinate at each triangle, and compute camera parameters by using the local coordinate transformation. The algorithm computes orientations and displacement relationships among the triangles in the scene while correcting the previously computed camera parameter values. In order to find optimal solution, we set optimization variables as camera calibration parameters and coordinate transformation values between local coordinates. The background eliminated images and calculated camera parameters allow us to reconstruct a 3D target object in VRML. The merit of this algorithm is in handling varying focal camera, in easy initial guessing value computation and in using fewer feature points compared to Zhang’s calibration method.

Abstract: This paper presents a low luminance dynamic range converter that includes light recording and adjustment system for vehicle application under light insufficient environment. The development of vehicle electronic technology has improved traditional vehicle function. How to design a safety function system for vehicle become more and more important in vehicle industries. This work designs low luminance dynamic range converter circuit for vehicle application and provides a safety-driving environment. In the proposed method, we adopt video capture system to record light information from driving environment. An adaptive adjustment is adopted to re-arrange the histogram according to the distribution of luminance. Then, we use a series of test images and extract the characteristic value to train the system to reflect practical circumstances. Next, color calibrations and de-noise processing are performed to improve the visual quality. The presented approach considers the realistic driving situation and provides a bright and safe visual environment for driver under light insufficient environment.

Abstract: In this work, we study the pedestrian position tracking problem using a foot-mounted inertial measurement unit (IMU). The IMU consists of a tri-axis rate-gyro, a tri-axis accelerometer and a tri-axis magnetometer. The magnetometer is used for constructing a global reference frame at the initial phase. The pedestrian orientation and position are estimated by integrating signals of the rate-gyro and the accelerometer. Since the integration operation usually introduces unbounded drift errors, a new drift reset method derived from a constant-ground-normal condition is proposed to compensate for the accumulated drift error. Furthermore, a temperature compensation (TC) method is described which can alleviate the rate-gyro error due to temperature variation. Real experiments have been conducted with six subjects to test the performance of the proposed method and the results show the promising performance of the proposed tracking system.

Abstract: In an electro-mechanical integration system where loads consist of a mechanical system, the electrical system specification and configuration will depend on the mechanical system. Therefore, inaccurate parameters of the mechanical system will make difficult the selection of electrical system specification and the effective controller design. Of these, the controller design often adopts an experimental method or a method using numerical analysis. With such methods, however, it is difficult to predict the actual system in advance followed by specification selection and controller design. Hence, to perform a faster and more accurate modeling of the system, a collaborative analysis is required for two physically different systems in a virtual space. In the present article, a method of an electro-mechanical collaborative analysis is proposed for an elevator door drive system. From mechanical load modeling using simulation, an electrical requirement specification has been derived. In addition, a C++-based collaboration program has been developed that can connect mutually different physical domains according to the proposed collaborative analysis procedures. The proposed modeling technique and program have been verified through simulation and experimental result.

Abstract: In this study, we proposed an innovative design for mechanical ventilation by applying the previously implemented optimal respiratory control simulator as the controller of an experimental ventilation device. Instead of providing a fixed airflow pattern, an optimal spontaneous flow pattern was optimized by the simulator based on patient’s estimated respiratory mechanics and was applied to drive a ventilation device. We also implemented an experimental ventilation control system, including the simulator, a ventilation device, an artificial lung, and a feedback control mechanism to attain minimum work of breathing during mechanical ventilation. The experiments were elaborated to verify that once patient’s respiratory physiology was significant changed, the breathing signals and measured respiratory mechanics were instantaneously monitored, and the optimization process was renewed by the simulator under the feedback control strategy.