Development of an Autonomous Driving Smart Wheelchair for the Physically Weak

People who have difficulty moving owing to problems in walking spend their lives assisted by wheelchairs. In the past, research has been conducted regarding the application of various technologies to electric wheelchairs for user convenience. In this study, we evaluated a method of applying an autonomous driving function and developed an autonomous driving function using ROS. An electric wheelchair with a control unit designed to enable autonomous driving was used to test the basic performance of autonomous driving. The effectiveness of the technology was confirmed by comparing the results of autonomous driving with those of manual driving on the same route. It is expected that the evaluation and improvement of the usability and ride quality as well as additional studies will help improve the mobility convenience of physically disabled persons.

Optical encryption using phase modulation generated by thermal lens effect

We present the implementation of an experimental optical encryption configuration in the Fresnel domain using the thermal lens effect to modulate the phase of the illumination beam. We corroborate the basic performance of our cryptosystem by performing the encryption-decryption procedure of a single object. Then, we test the tolerance of the proposed scheme to decrypt decryption with keys registered for different modulations of the illumination beam induced by the phase generated due to thermal lens effect. These different phase modulations are obtained by introducing axial displacements of a sample, where the thermal lens effect is induced by an excitation beam. Considering the phase modulation changes in the illumination due to sample displacements, we propose an undercover procedure to further protect the target information using decoy data. The key associated with the target information is obtained when the probe and excitation beams are focused on the same point of the sample, while the decoy object key is registered when the beams are not focused on the same region of the sample. Finally, we analyzed the resistance of the undercover ciphertext to some of the attacks reported in the literature. All experimental results presented in this work demonstrate the basic capabilities, viability, and versatility of our proposals.

Exploration on the Materials Quality Control of Railway Vehicle Weld Structure Based on Service Safety Demand

With the continuous increasing of service-rail-vehicle in China, some defects such as cracks appeared at different stages of service when they had not reached the design life, while current theories and methods cannot explain the appearance of defects, which brought risks and hidden dangers to the operation of the vehicles. It was found that the reasons were mainly caused by one or several factors such as material performances, design, manufacturing process and operating environment. Since more and more sensors being installed on the vehicles to supervise the health of structure, it is more improtant to focus on the performances of materials. Through comparing different material standards including international, national, railway industry and enterprise standards, as well as the technical delivery conditions of other industries, it was recommended that the fracture mechanical parameters such as fracture toughness and fatigue crack growth should be proposed into the materials quality control regulations of original equipment manufacturers (OEMs). Furthermore, based on the testing data of materials from OEMs, several suggestions were proposed on the basic performance of materials such as raising the requirements contained impact, metallography and corrosion resistance properties in order to provide guarantee for the service safety of vehicles.

Experimental Study of a New Concrete Admixture and Its Function in Filling and Reinforcing Granite Fissures

A concrete admixture with water retention and superhydrophobic properties was developed according to the high tensile strength, fissure resistance, and antiseepage requirements of concrete linings. Capillary water absorption, early-age anticracking, cube compressive strength, and splitting tensile tests were employed to study the effects of the new concrete admixture on the basic performance of concrete. On this basis, a triaxial compression test was conducted on granite fissures filled with concrete containing the admixture; the stress-strain and failure characteristics under different admixture dosages, confining pressures, and fracture widths were analyzed, and the reinforcement effect of the concrete with the admixture on the fractured rock mass was studied. The results show that the admixture can effectively improve the ability of concrete to resist water and fissures, and the concrete with the admixture significantly reinforced the fractured rock mass. Therefore, it can be widely applied in filling and reinforcing fractured rock masses.

Simplified cascade multiphase DC-DC buck power converter for low voltage large current applications: part I --- steady-state analysis

This paper presents a new simplified cascade multiphase DC-DC buck power converter suitable for low voltage and large current applications. Cascade connection enables very low voltage ratio without using very small duty cycles nor transformers. Large current with very low ripple content is achieved by using the multiphase technique. The proposed converter needs smaller number of components compared to conventional cascade multiphase DC-DC buck power converters. This paper also presents useful analysis of the proposed DC-DC buck power converter with a method to optimize the phase and cascade number. Simulation and experimental results are included to verify the basic performance of the proposed DC-DC buck power converter.

Convenience of Hgb-O detected by optical method in XN-series hematology analyzers in evaluating hemoglobin concentration in samples with chylous turbidity

The chylous turbidity of blood samples is one of the causes of false-high hemoglobin (Hgb) concentration measurements by the colorimetric method, which has been widely applied in hematology analyzers. In such cases, additional manual procedures are required to correct Hgb concentrations. We therefore examined the effectiveness of an optical method for measuring Hgb concentrations in samples with chylous turbidity using Hgb-O in the reticulocyte channel equipped in XN-series analyzers (Sysmex, Kobe, Japan). Hgb-O showed excellent basic performance, including linear correlation and invariability with sodium lauryl sulfate (SLS)-Hgb detected by the colorimetric method. In the analysis of samples from healthy volunteers supplemented with fat emulsion, chylous turbidity did not affect Hgb-O but SLS-Hgb, which was falsely increased according to the dose of fat emulsion. Actually, SLS-Hgb was falsely elevated in 34 of 40 chylous turbidity 3+ samples. The remaining 6 samples were measured in hematology analyzers where Hgb-O was inconsistent with SLS-Hgb in the internal quality control records. For these samples, the correction factors calculated from the internal quality control records could contribute to providing the corrected Hgb-O value. These findings suggested that the optical method was effective and convenient for accurately evaluating Hgb concentrations in samples with extremely chylous turbidity.

Evaluation of Properties and Micro-Characteristics of Waste Polyurethane/Styrene-Butadiene-Styrene Composite Modified Asphalt

In order to solve the problems caused by asphalt diseases and prolong the life cycle of asphalt pavement, many studies on the properties of modified asphalt have been conducted, especially polyurethane (PU) modified asphalt. This study is to replace part of the styrene-butadiene-styrene (SBS) modifier with waste polyurethane (WP), for preparing WP/SBS composite modified asphalt, as well as exploring its properties and microstructure. On this basis, this paper studied the basic performance of WP/SBS composite modified asphalt with a conventional performance test, to analyze the high- and low-temperature rheological properties, permanent deformation resistance and storage stability of WP/SBS composite modified asphalt by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. The microstructure of WP/SBS composite modified asphalt was also observed by fluorescence microscope (FM) and Fourier transform infrared spectroscopy (FTIR), as well as the reaction between WP and asphalt. According to the results of this study, WP can replace SBS as a modifier to prepare WP/SBS composite modified asphalt with good low-temperature resistance, whose high-temperature performance will be lower than that of SBS modified asphalt. After comprehensive consideration, 4% SBS content and 15% WPU content (4 S/15 W) are determined as the suitable types of WPU/SBS composite modified asphalt.