bluuebunny/crossref_metadata_2025 huggingface dataset:
Co-simulation of transfer alignment and CAN busbased on CANoe-MATLAB
Authors: Yongsheng Wang , Wei Luo , Fan Zha
Published: January 2020

The research on rapid transfer alignment for INS on moving base is very important in the field of the inertia technology. In order to build the real-time CAN bus network simulation system with the velocity matching model of the transfer alignmentalgorithm, CANoe(CAN open environment)-MATLAB interface is applied. The CANoe-MATLAB interface is connected with MATLAB/Simulink which has powerful modeling functions and CANoe which has perfect function of bus simulation. Modeling the transfer alignmentalgorithm by MATLAB/Simulink and providing the real-time CAN bus network communications in HIL(hardware-in-loop) simulation by CANoe. The simulations tests show that co-simulation system built by the CANoe and the MATLAB/Simulink performs favorably with rapid convergence and validity.
Effect of twist angle on starting capability of a Savonius rotor – CFD analysis
Authors: Zakaria Ahmad , Ibrahim M S N
Published: January 2020

Starting capability is an important feature of any high performance wind turbine. This parameter is usually referred to the rotor static performance. In this paper, the results of CFD analysis on four Savonius rotor designs are presented with the objective of investigating the effect of twist angle on the starting capability. Essentially it is a comparison between a conventional Savonius rotor and three helical rotors with 0°, 90° and 180° twist angle. The proposed methodology was first validated against the published wind tunnel test data. The best parameters were then used to evaluate the static performance of the four Savonius models. It is observed that helical Savonius rotor contributes to positive static torque coefficient for all rotor angles. The rotor with 90° twist angle gives the highest average static torque coefficient of 0.442 followed by 0° twist angle rotor and 180° twist angle with static torque coefficient of 0.434 and 0.385 respectively. This improvement in static torque coefficient will not only contribute to the better starting capability but also to the overall performance of Savonius rotor.
Finite element analysis of automotive arm brake pedal for rapid manufacturing
Authors: Sargini MIM , Masood SH , Palanisamy Suresh , Jayamani Elammaran , Kapoor Ajay
Published: January 2020

Current automotive arm brake pedal uses conventional manufacturing method such as metal press and CO2 welding processes, which are known to be heavy, costly and demand higher quality control. This paper will discuss how finite element analysis can be applied to optimise the design of a brake pedal for Rapid Manufacturing application based on current additive manufacturing process to produce automotive brake pedals with reduced material weight. The performance of the new design is compared with the current design of arm brake pedal to realise the potential of rapid manufacturing to save time and cost in automotive parts.
Research on improvement of high utility pattern mining algorithm over data streams
Authors: Guo Feng , Li Yuqiang , Li Lin
Published: January 2020

Aiming at the problem that the existing algorithms for high utility pattern mining over data streams based on sliding window have multiple datasets scans or redundant items, an efficient HUIGRT algorithm for mining high utility patterns over data streams based on global revision header table is proposed in this paper. First, the global revision header table and the utility tree are constructed. The global revision header table is used to store the items and transaction utility of the current data domain that need to be processed, and the utility tree is used to store all of the utility information on the item sets in the transactions to avoid multiple datasets scans. Then, this algorithm can mine all high utility patterns using the global revision header table and the utility tree. Finally, the redundant items are deleted by revising the global revision header table, meanwhile the utility tree is updated to fill in new data. This paper compares the algorithm with the existing high efficiency algorithm HUPMS and HUM-UT on the three datasets with different sparse: Mushroom, T10.I4.D100K and Retail. The results show that the space-time performance of HUIGRT algorithm is better than the two other algorithms.
DBSCAN-KNN-GA: a multi Density-Level Parameter-Free clustering algorithm
Authors: Mu Bin , Dai Meng , Yuan Shijin
Published: January 2020

DBSCAN is a popular tool to analyse datasets which can effectively discover clusters with arbitrary shapes. However, it requires two input parameters which are difficult to be determined, according to the fact that the performance of clustering result depends heavily on user-specified parameters. In addition, it uses global parameters which are not appropriate to those multi-density datasets. Aiming at these problems, we propose a parameter-free algorithm to perform DBSCAN with different density-level parameters. We select some classical datasets and a TLC taxi trip record used for experiments to compared our proposed algorithm with the original DBSCAN to evaluate the performance of our improved DBSCAN. The results show that the proposed algorithm is capable for efficiently and effectively detecting clusters automatically with variable density-levels. Compared with original DBSCAN, the proposed algorithm can discover more noise points and its execution accuracy is higher.
Optimal mission planning of active space debris removal based on genetic algorithm
Authors: Chen Yang , Bai Yuzhu , Zhao Yong , Wang Yi , Chen Xiaoqian
Published: January 2020

With the increasing space activities, the space debris has seriously deteriorated the safe performance of the on-orbit spacecraft and has attracted much attentions. To reduce the rising influence of the space debris and improve the safe performance of the space mission, the three-stage removal strategy for space debris is proposed in this paper. Firstly, the multiple spacecrafts including one main spacecraft and some following spacecraft for space debris removal mission is developed. Then, the fuel, time and the quantity of the following spacecraft are defined as the constraints. Moreover, using the minimum fuel consumption as the optimal object, the mathematical model of the debris removal problem is established. Finally, the genetic algorithm is applied to solve this problem. Compared with the prior space debris removal strategy, the proposed three-stage space debris removal can effectively reduce the fuel consumption. Numerical simulation verifies the effectiveness of the proposed space debris removal scheme.
Statistical testing data generation for UAS
Authors: Sui Jianwei , Gong Yunzhan , Jin Dahai , Wang Yawen
Published: January 2020

The reliability of UAS(Unmanned Aircraft Systems) is of vital importance in practical applications. The most effective method to guarantee the reliability of UAS is to test UAS with multiple types of testing data. In this paper, we propose a method for the testing data generation of UAS in consideration of the combination and weight of the input data, which improves the availability of the method in UAS. Then we make four experiments to verify the effectiveness of the proposed method: (1) the random testing data generation experiment; (2) testing data generation considering the combination of input data experiment; (3) testing data generation considering the combination and weight of input data experiment; (4) the history data from the actual usage situation. Experiments results show that the method proposed in this paper is closer to the reality. At last, we analyse the code coverage by using Code Test System(CTS). And the analysis reflects that the proposed method has a better coverage than other methods.
A scheme of D2D-based delay analysis and vehicle relay algorithm in VANET
Authors: Zhao Yinze , Jiang Lingyun
Published: January 2020

The D2D-based VANET (Vehicular Ad-hoc Network) makes up for the defects of the traditional IEEE 802.11p network, and has the advantages of low latency and high throughput. In order to reduce the delay of message transmission between vehicles, a D2D-based hybrid V2I/V2V (Vehicle-to-Infrastructure/Vehicle-to-Vehicle) IoV (Internet of Vehicle) architecture was considered, which firstly clusters vehicles on the road according to motion consistency. The message is transmitted between the clusters, and in addition to being transmitted through the RSU (Road Side Unit), it can also be relayed by establishing a D2D link between the vehicles. Based on the SINR (Signal to Interference plus Noise Ratio) and the minimum capacity constraint, the optimal transmission path is selected by predicting the delay of each cellular link and D2D link to reduce the end-to-end delay. In addition, for accurate modeling and analysis, a three-step method is used to predict and compare end-to-end delays. The simulation proves that this relay algorithm significantly reduces the delay compared with other methods.
An improved authentication scheme for Internet of things
Authors: Xie Zhongliang , Jiang Lingyun
Published: January 2020

Designing a secure authentication scheme is of great importance to the practical applications of the Internet of Things (IoT). In 2017, Wang et al. proposed an improved mutual authentication scheme for the embedded devices and a server over Kalra et al.’s and Chang et al.’s. And they provided a formal proof for their scheme. However, their scheme is still insecure and cannot resist against key compromise impersonation (KCI) attack. In the paper, we first demonstrate the shortcoming of Wang et al.’s scheme, and then we carry out an improvement over Wang et al.’s scheme to address the revealed issue by using an auxiliary server.
Fault diagnosis of power transformer based on tree ensemble model
Authors: Liu Yunfei , Li Jing , Qiao Lin , Chen Shuo , Liu Sai , Liu Jiahua
Published: January 2020

During the running operation of the oil-immersed transformer, some gases may be dissolved in the insulating oil which can be used to diagnose the incipient failure of the power transformer. This is the Dissolved Gas Analysis (DGA). This paper proposes a power transformer fault diagnosis method based on tree ensemble model (Extreme Gradient Boosting, XGBoost): constructing a large number of classification and regression trees (CART) to fit the residuals obtained by each learning. Compared with the commonly used SVM and BPNN methods, our method has a significant improvement in accuracy, F1-score, precision and recall.
Real time outlier monitoring for power transformer fault diagnosis based on isolated forest
Authors: Shen Li , Du Hongjun , Liu Shuji , Chen Shuo , Qiao Lin , Liu Sai , Liu Jiahua , Li Kexin , Li Jing
Published: January 2020

In order to improve the accuracy and efficiency of transformer fault detection, this paper uses the isolated forest algorithm combined with the historical transformer characteristic gas data to establish the characteristic gas outlier recognition model, and then uses the uncoded ratio method to establish the abnormal event strategy and abnormal event library for the transformer historical fault information. Finally, the state of the transformer is diagnosed based on the established outlier detection model and the exception event library. The experimental results show that the proposed method has a great improvement in the detection efficiency and stability of outliers, and is more accurate in transformer fault diagnosis combine with abnormal event database.
Design and implementation of fault injection based on abstract syntax tree of C Program
Authors: Yu Hang , Gong Huiquan , Wang Yawen
Published: January 2020

Mutation testing is a fault-based technique to evaluate test quality by injecting bugs in programs under test. Traditional manual fault injection has many disadvantages such as inefficiency, large workload, low compilation success rate and so on. To improve the efficiency of fault injection, this paper aims to develop an automatic tool that supports fault injection for programs written in C. This paper first introduces the types of mutation operators and injection rules. Then, it proposes a framework, which mainly includes four modules: parser, fault location extraction, fault generation and data model. Finally, experiments show that our tool not only aids to produce a large number of program faults but also provides syntax-correct mutant programs, which would be further used in mutation testing.
Video stalling detection method
Authors: Yu Shushi , Wang Na
Published: January 2020

ISP providing network access services has a huge user group; therefore the competition between the ISP providers is extremely fierce. Under the situation that video occupies the most of network flow, providing high satisfaction network services for video users can effectively improve the competitiveness of ISP, in which video Stalling plays an important index. For protecting the privacy of users, most video websites use HTTPS as the application layer protocol for video transmission, so ISP could not get the playback of video users by parsing HTTP packets, and could not directly detect the video users. In this assay, a new method, protocol transport layer Video Stalling Detection Method based on HTTPS is proposed. This method can effectively match the YouTube, Youku, Letv, Tencent video and other major video sources of the stalling event.
Effects of residual stresses and shape deformities on failure of rollover protective structures
Authors: Abou-Hanna J. , Tahamtam S. , Kumareshan V.
Published: January 2020

Rollover Protective Structures (ROPS) are manufactured typically from components that require forming such as pipe bending process. The manufacturing process creates residual stresses and shape deformities in the pipe structure. These parameters in turn may affect the strength of the pipe to bear the load during rollover. Conventional modeling does not capture the effects of residual stresses and shape irregularities in the pipe resulting from forming. A detailed analysis is therefore required to determine the significance of the manufacturing process on the strength of ROPS. Finite Element Method (FEM) is employed to simulate the bending process. Residual stress and deformation data from bending process analysis are used to further investigate failure of the structure under different loading conditions. The maximum load the structure can withstand, before it loses its stiffness, under a specific displacement is referred to here as failure load. Results revealed that there is a significant difference in the failure loads due to presence of bending process induced residual stresses and due to shape deformities. The model with the residual stresses and shape deformities has higher failure loads as compared to the conventional model. It also has been noted that residual stress is the main contributing factor to this increase in failure load. Parametric study was performed to investigate the effect of pipe wall thickness and radius of the formed bend on the failure loads.
Study on the impact of LNG carrier entering and leaving port on the passing capacity of narrow channel
Authors: Huang Tai-kun , Pang Ran , Wang Yuan-zhan , Yang Xing-yan , Jia Han
Published: January 2020

As a clean energy source, LNG has been widely used. LNG ships need to enter and leave the port area through the channel. With the development of the port, the ship traffic will gradually increase. As a manual excavation of narrow and long channel, its passing capacity will become a constraint factor for LNG receiving stations and port development. In this paper, the system simulation method is used to study the impact of LNG ship entry and exit on the passage capacity of the channel, which can provide basis and reference for the planning, site selection and channel construction of the LNG receiving station.
Information cascade prediction based on T-DeepHawkes model
Authors: Wang Shijie , Zhou Lihua , Kong Bing
Published: January 2020

It is an important research point of social network analysis to predict future propagation range of information based on its early propagation characteristics. DeepHawkes model combines the Hawkes model in the traditional methods with deep learning, which not only inherits the high interpretability of Hawkes model, but also contains the high prediction ability of deep learning. However, the DeepHawkes model ignores the effect of the text content of the information on the propagation. Therefore, on the basis of DeepHawkes model, this paper further considers the influence of the text content on the diffusion, and proposes a T-DeepHawkes model which merges a topic classification model into DeepHawkes model. The experimental result shows that T-DeepHawkes model has a better prediction accuracy.
Fine-grained analysis method for Android volatile memory
Authors: Feng Peijun , Li Qingbao , Chen Zhifeng
Published: January 2020

Android dominates the mobile operating system market. Volatile memory analysis of Android devices has been the focus of research on mobile forensics technology. However, due to the semantic gap between the kernel and the volatile memory allocator, existing Android volatile memory analysis methods are coarse-grained. With the volatile memory capacity of Android devices increasing, these methods cannot satisfy the need of Android volatile memory analysis accuracy. In this paper, we first discuss the address space layout of Android processes and the management mechanism of Jemalloc, the default Android volatile memory allocator. Then, we bridge the semantic gap by utilizing the boundary auto alignment feature of the data structure of Jemalloc. Finally, we propose a Fine-grained Analysis Method for Android volatile Memory, called FAMAM. Experimental results shows that FAMAM has an accurate data analysis capability as well as a good robustness. In addition, we successfully use FAMAM to discover new storage patterns for username and password of Wechat.
Reservoir inflow prediction using a hybrid model based on deep learning
Authors: Luo Bin , Fang Yang , Wang Handong , Zang Di
Published: January 2020

Reservoir inflow prediction plays a significant role in the field of hydrological prediction. Accurate and reliable prediction of reservoir inflow is the key to flood control decision. In this paper, we combine the deep belief network (DBN) with the Long Short-Term Memory (LSTM) to present a hybrid model based on deep learning (HDL) for reservoir inflow prediction. We take a full consideration of the basin flow and rainfall factors, which significantly affect the inflow flow. According to the rainfall data, we divide the corresponding flow data into two cases: rain and no rain. The proposed approach consists of three parts: we apply the DBN to learn the characteristics of the flow data and get predicted values of the reservoir inflow in case of rain and in case of no rain respectively. Then, we use the basin rainfall data and adopt the LSTM to fit the differential between the predicted inflow value generated by DBN in case of rain and the real inflow value, and get the predicted differential. Finally, the outputs of these three parts are added to obtain the final predicted result. Experiments are evaluated by the historical flow and rainfall data of a reservoir in China, and the results have proved that our method is effective and has higher prediction accuracy.
Rapid entry trajectory planning without segmentation
Authors: Jun Li , Zheng-yu Jiang
Published: January 2020

A new rapid entry trajectory planning algorithm for hypersonic glide vehicles is presented in this paper. Firstly, build a new technique to calculate the boundary of the control variable that satisfy the path and control constraints without using quasi-equilibrium glide condition (QEGC). Secondly the optimal control variable is expressed as function of current state. Then combine two of them by control coordination. Finally, introduce one or two constant parameters to satisfy the final state condition. The approach is tested using the CAV model. This algorithm is efficient and will provide feasible trajectory without reversal of bank angle. It can apply for entire entry process, segmentation and the QEGC is unnecessary.
Multi-echelon inventory allocation of multi-indenture spare parts considering maintenance ratio
Authors: Xia Jun , Feng Yunwen , Xue Xiaofeng , Lu Cheng
Published: January 2020

The existing multi-indenture spare parts maintenance has a certain maintenance proportion, a multi-echelon inventory allocation method with maintenance ratio for multi-indenture spare parts was proposed. Multi-echelon inventory allocation model for multi-indenture spare parts was established, which integrates maintenance rate into METRIC (Multi-echelon technique for recoverable item control) model, and then the marginal analysis method was applied to solve this model. First, the theory of multi-echelon inventory allocation model with maintenance ratio for multi-indenture spare parts was elaborated, and the mathematical model was established with the spare parts inventory cost as the optimization objective, the fleet availability as the constraints. Then, the procedure of solving the model by using marginal analysis method is discussed. Finally, taking an aircraft multi-indenture LRU (Line repairable units) as the research object, multi-echelon inventory allocation was investigated by considering maintenance ratio. The feasibility and effectiveness of the developed method are verified by an example analysis.
Research on integrated logistical support systems of medium altitude long endurance UAS
Authors: Haoran Deng
Published: January 2020

The Medium Altitude Long Endurance (MALE) UAS in modern warfare is becoming more and more widespread, which makes the UAS more and more frequently used in warfare. The equipment characteristics of UAS are embodied in the following aspects. The composition of UAS is complex, Ground Stations is distributed deployment, Mission payloads can flexibly change, and the whole system need highly cooperative ability between air and ground. That put forward higher requirements for integrated logistical support system of UAS. Aiming at the unique support characteristics of UAS, this paper constructs the integrated support system of UAS based on the integrated support system of traditional aircraft, which is mainly reflected at five aspects: support organization, support resources, support function, support process and support management. This systems can ensure the integration of all support links in the actual process of UAS support, and meet the operational and mission requirements of UAS to the maximum extent.
Why a run-to-fail strategy is not good practice for SIS?
Authors: Vora Keyur G.
Published: January 2020

The Maintenance & Reliability engineers understand pain area that the portion before the “flat” part of the “Bathtub” is where a high number of premature failures can occur: commonly referred to as “infant mortality”. One of the fundamentals of the Probability of Failure on Demand (PFDavg) calculations in SIL verification analysis, is the concept of a constant failure-rate during useful life of the equipment. Probabilistic calculations assume that the failure rate of the devices used in a Safety Instrumented System (SIS) remains constant during the “flat” (constant failure rate) portion of the “bathtub” curve. Most manufacturers will perform stringent testing to weed-out, weaker units that could fail prematurely, leading to unwanted warranty claims. When equipment reaches to flat portion of it’s lifetime called as “wear-out” phase then the failures start to rise dramatically & then the integrity of the Safety Instrumented Functions (SIF) is compromised. During the Operation and Maintenance phase of the SIS, periodic performance assessments need to be made in order to ensure the as-designed, installed and commission SIS and its SIFs, still meet the performance requirements of the Safety Requirement Specification (SRS) [1]. Using a run-to-fail strategy will not enable the SIFs to meet the performance requirements once wear-out occurs. This paper will explain why a run-to-fail strategy is not good practice for a SIS, which will lead to the de-graded performance of the SIFs. This paper addresses both the design and operational impacts of a run-to-fail strategy.
Design of non-contact fuel consumption real-time monitoring system for BDS positioning special vehicle
Authors: Zhang Pengwei , Guo Chengliang , Wu Yongjie , Wang Wenjun , He Bingyang , Zhang Yuanfa
Published: January 2020

The fuel consumption measure is inaccurate and no real-time with the three-scale mete in the special vehicles, so the real-time fuel measurement system is developed with the technologies of ultrasonic sensing, single-chip microcontroller, BDS positioning and wireless communication. An ultrasonic oil level sensor is stuck on the bottom of each tank to detect the remaining oil of tanks accurately. It can avoid destroying the existing equipment structure. BDS positioning module is applied to monitor the location of vehicle. This technology is China complete autonomy. The special wireless transmission module and special network node are set up for transmitting the data of fuel consumption and position. It can guarantee the transmission secure and confidential. And a fuel consumption detection algorithm is studied with BDS measuring distance. The prototype is tested in four different road conditions. The error rate of oil detection on a highway with good conditions is 3.92%. And the measured fuel consumption value is close to the manufacturer’s nominal value. The analysis of experimental data shows that the design of the detection system is reasonable and the fuel consumption detection algorithm is correct and reliable, and real-time fuel detection and positioning for the special vehicles can be realized.
Calibration method of curvature distortion in step height measurement by atomic force microscopy
Authors: Li Wei , Yu Xixi , Gao Sitian , Shi Yushu , Li Shi , Huang Lu , Zhang Shu
Published: January 2020

Atomic force microscopy (AFM) is widely used to characterize the surface topography in nanomaterials and biology research since the high resolution in 3 dimensions. Height measurement is important in the investigation of graphene thickness. Due to some AFMs use tube scanner, the curved scanning distortion will cause height measurement error. Step height standards calibrated by metrological AFM are used to calibrate the Z axis of conventional AFMs. However, for step structure with large width, the method specified in ISO 5436 is not suitable. The distortion of the curvature scanning is discussed for different samples, and for large step width the influence is significant. So the substrate correction method is proposed to eliminate the scanning curvature and the comparison with several other fitting correction methods is also discussed.
Synthesis and experimental investigation of PZT nanocomposite films
Authors: Janusas Tomas , Janusas Giedrius , Palevicius Arvydas , Ciganas Justas
Published: January 2020

In this paper, synthesis of nanocomposite and experimental investigation of three samples of nanocomposite films are presented. The aim of this research is to determine influence of the PZT particle concentration in nanocomposite on the surface morphology, qualitative and quantitative chemical composition ant direct piezoelectric effect. The specimens were prepared by mixing the PZT nanopowder with PMMA in three different proportions: 85% of PZT and 15% of binder; 90% of PZT and 10% of binder; 95% of PZT and 5% of binder. Surface morphology and qualitative and quantitative chemical composition were evaluated using scanning electron microscope, which is equipped with the Energy Dispersive X-Ray Spectrometer. Electrical response of the pulse-excited specimens is also presented.
An automatic grading system for electronic medical records with neural network
Authors: Liu Yi
Published: January 2020

Automatically grading electronic medical records from clinical researchers is an important task on healthcare research. In this paper, we present a convolutional neural network framework to grade medical records by grading note. We regard the scoring process as a text pattern classification task with mapped sentences from grading concept rule to medical records. This framework involves two stages. The first stage is key medical concept matching between grading note and medical records. The second stage is text pattern classification which can predict whether the key concept in grading note is correct, missing or incorrect. The result shows that our neural network model performs better than other traditional machine learning grading methods. Our system makes a great progress for text pattern classification accuracy and performs much better baselines on grading process.
The disc expansion model to determine the MIC of a planar bounded connected domain
Authors: Zhou Min
Published: January 2020

To determine the maximum inscribe circle (MIC) of a planar bounded connected domain which can be represented as a generalized polygon (with arcs edges), a disco expansion model is proposed. The model simulates a disc continues expanding process in a polygon without friction. When it cannot expand, the three contact points which are both on the circle and the sides of polygons are just the points to determine the MIC. The implementation algorithm of the model for convex polygon is also given. For generalized polygons with arcs or concave points, bottleneck lines as soft edge are adopted to partitioned the polygons first. Then, the proposed model can be applicable for generalized polygons with little modification.
Improved non-local mean denoising algorithm based reliability of reference pixel
Authors: Lee Junghyun , Jeong Jechang
Published: January 2020

In this paper, we propose a method for improved the non-local mean denoising algorithm by using the similarity in comparison with reference pixels. The noise in image is eliminated by the calculation to follow values as the patterns are similar in non-local mean denoising alogirthm. In the conventional algorithm, all the comparison results of the pixels are included in the denoising process, and even the low similarity result is included. The method causes the denoised effect to incorrect. In this paper, we propose an algorithm that reduces the influence of low-similarity reference pixels or improves the effect of high-similarity reference pixels. The proposed method improves both the object quality and the subject quality.
Study of low and high temperature oxidation of n-pentane at supercritical conditions in a jet stirred reactor
Authors: Yang Yifu
Published: January 2020

The intermediate/low and high temperature oxidation of n-pentane from atmospheric pressure to supercritical pressures (1-100 atm) was studied by using Chemkin, a commercial software. A recently developed n-pentane model was used to predict the temperature evolutions of major and intermediate species, like n-pentane, O2, CO, CO2, CH2O, C2H4, CH3CHO at varied pressure and temperature conditions. It is found that as the environmental pressure increases, the difference between high temperature oxidation and low temperature oxidation becomes less obvious because the negative temperature coefficient (NTC) is decreasing (at 10 atm and 100 atm, high temperature oxidation occurs right after low temperature oxidation). At supercritical pressures, the high temperature oxidation is governed by the branching reactions of RO2, and the addition reaction of QOOH with oxygen dominates the reaction paths at both low and high temperature oxidations because the addition reaction between QOOH and oxygen is still more important than the decomposition reaction of QOOH at high temperature and 100 atm. According to the pathway analysis and sensitivity analysis, the branching reactions of RO2 are dominating at both low and intermediate to high temperatures.
Evaluating the impact of using various biodiesel blends on the performance of diesel engine at variable load conditions
Authors: Abu-Zaid Mahmoud
Published: January 2020

Recently, researchers use various types of alternative fuels, for diesel engines. Previous studies, reveals that biodiesel with renewable origin, is the most promising alternative fuel, with less impact on the environment. The objective of this paper, is to determine experimentally, the impact of using different biodiesel blends, extracted from Sun flower, Palm, and Corn oils, on the performance on diesel engine. The engine was operated at variable load and fixed speed. The following main parameters were determined: Torque, Brake power, Brake Specific Fuel Consumption (BSFC), Brake thermal efficiency, Fuel consumption, and Exhaust temperature. Results show that when all the biodiesels were used as a fuel to the engine, the engine has lower BSFC and exhaust temperature, and higher brake thermal efficiency, than when using pure diesel as fuel for the engine. This implies that using the biodiesel blends is more economically than using pure diesel as a fuel for the engine. In addition, it was concluded that using all these blends produces less NOx emissions.
The effects of flexible vortex generator on the wake structures for improving turbulence
Authors: Dol Sharul Sham , Chan Hiang Bin , Wee Siaw Khur , Perumal Kumar
Published: January 2020

Turbulence is a very useful flow characteristic that is used in many engineering devices to facilitate mixing, heat transfer in heat exchanger and improving aerodynamics in propeller. This paper has numerically studied the spatial characteristics of the wake behind a free-oscillating flexible vortex generator (FVG) in order to evaluate its turbulence generation ability. As the wake is playing as the effective turbulence region, the spatial characteristics can reflect the ability of the FVG in turbulence generation when a larger wake size indicates a greater turbulence region. Two VGs are considered in this study; circular and flat plate cantilever. Each VG was submerged individually in a subcritical flow (102 <ReD < 105) and the generated wake was studied. The wake behind the FVG was visualized via the lambda2 vortex identification criterion and it was compared with its respective rigid counterpart. From the comparison, it is found that the FVG has a larger wake compared to its rigid counterpart. The result demonstrates that the FVG can generate a larger turbulence region. The cause of the increasing wake size was found to be the weakening of downwash behind the FVG when it bends. The downwash becomes weaker as the deflection of the FVG increases.
Calculation and analysis of gyroplane trimming characteristics
Authors: Xiang Y , Wang J , Cao Y , Wei N
Published: January 2020

In order to analyse the trimming characteristics of gyroplane, a complete nonlinear dynamic equation is established, which is a seven-degree of freedom model. By using constraints, the quantity of unknown variables is equal to the quantity of equations. In the process of solving the equation, Levenberg-Marquardt algorithm is applied. After comparing the results of mathematical model to the flight test, it can be concluded that the seven degree of freedom model is valid.
Supporting mechanism design of parachutes for 2.4m×2.4m transonic wind tunnel in CARDC
Authors: Hao Dong , Zhang Lin , Yu Jing , Mao Daiyong , Yang Xianwen
Published: January 2020

In order to carry out the wind tunnel test of the parachutes in 2.4m×2.4m transonic wind tunnel of CARDC which is located at Mianyang, a supporting mechanism for the attack angle from 0 to 25 degrees at Mach 0.4 and 0.8 is designed and optimized in the present paper. Three section shapes (circle, ellipse, and airfoil) are utilized to analyze the aerodynamic characteristics and mechanical performances of the designed supporting mechanism. The aerodynamic and mechanical simulated results of the three different section shapes are compared and discussed. The optimized design is verified by wind tunnel experiments. The results show that the section shape of circle has the largest modal frequency of first order (53.497Hz), the smallest Mises stress (34.1MPa) and displacement (0.4735mm). It is the best section shape of the three for the supporting mechanism. The investigation in the present paper has a good significant meaning to the testing technologies of the wind tunnel experiments for parachutes.
The study of properties of metal rubber damper used in thruster
Authors: Duan Fu-Wei , Tao Yuan , Ding Cheng-Bin , Yu Ming-Fei , Sun Jin-Chuan , Wang Ming-Liang , Liu Lu
Published: January 2020

Developed a new type of metal rubber damper to reduce the vibration of a certain type of thruster, researched the mechanical properties of this new damper and rubber damper with experiment. The results show that: the area of protection, the static load capacity and the energy consumption of metal rubber damper are better than rubber damper, it is useful to adjust the performance of the metal rubber damper by adjusting the density, height, pre-compression and other parameters. The study provides some reference for reducing vibration of thruster with metal rubber damper.
A recommendation of pension service based on user preferences and trust relationships
Authors: Zhang Kaiqi , Li Chunshan , Chu Dianhui
Published: January 2020

Recommendation technology have been widely used in social networks and many e-commerce websites, but there are few recommendations of pension service and those recommendation results are not accurate enough. For more accurately recommending personalized pension services to users, this paper proposes a recommendation method of pension service based on the user preferences and the trust relationships between users. Firstly, by mining user socialization relationship information, the degree of trust relationships between users is calculated, and the Pearson correlation coefficient is used to obtain the user similarity, then their results are combined and used to find the neighbour user set of the target user. Secondly, a timeliness model of user ratings based on the user evaluation time are established, which is used to determine the user’s preference for the service, and finally to predict the target user’s rating value for the project. The experiment takes the Douban review data and the users social data as the case to verify the results. The experimental results show that compared with the traditional recommendation method, the recommendation method based on user preferences and trust relationships improves the accuracy of recommendation.
Immediate measurement of fuel characteristics of bio-char using NIRS
Authors: Xue Junjie , Hu Xiaoying , Liang Hui , Wang Xiaodong , Haiyang LV , Yang Zengling , Dong Changqing
Published: January 2020

Low temperature pyrolysis is effective to improve the fuel quality of wheat straw and corn stover. To determine the pyrolysis condition and fully utilizing the solid product (bio-char), the fuel characteristics of the bio-char should be measured. It costs a lot of time and money to finish all the measurement, which really retards the development of the biomass industry. This study is supposed to immediately predict the proximate analysis parameters, ultimate analysis parameters and heat value of sixty-five bio-char using NIRS. The results show the fuel characteristics of the bio-char vary in a very big range. The NIRS models can predict the VM, FC, ash, HHV, oxygen, carbon, hydrogen contents of the bio-char accurately. The Rc and Rcv2 value are all bigger than 0.92 and the RPD are bigger than 3.59. The NIRS models can also tell the high or low content of moisture and nitrogen. Only for the sulphur, more work need to do to improve the accuracy of the NIRS models. Predicting the fuel characteristic of the bio-char only by scanning the NIR spectrum, which costs only 10 seconds, will really be helpful for the biomass industry.
Design and analysis of five probe flow analyser for subsonic and supersonic wind tunnel calibration
Authors: Rupesh Akhila , Muruga Lal Jeyan J V , Uthaman Sanas
Published: January 2020

The flow angularity in a wind tunnel plays a major role in test section when testing models. The models are being tested at a mixture of flow velocity. Usually a subsonic wind tunnel is calibrated using a normal Pitot tube and supersonic wind tunnels with high efficiency probes. The calibration of a wind tunnel includes determining the Mach number range ad pressure range throughout the test section of the flow throughout the pattern of operating velocity. In the analysis it is noted that the sensitivities of the calibrating instruments are maximum when it is either cone or wedge shaped. When the wedge or cone angles are maximum, more accurate results are also obtained, but it’s not possible to have a maximum angle cone or wedge because of the detached wave and tunnel blockage factors. Hence in order to overcome this difficulties in measurement, a five probe flow analyzer has been designed. The five probe flow analyzer is used to determine the wind tunnel test section parameters like flow angularity, Pitot pressures, static pressures, wave angles, and the presence of test section noise. Over to these parameter, the stagnation states can also be determined using this analyzer. The proposed model is designed by getting optimum solutions from previous analysis and the existing data by considering all the aerodynamic and mechanical loading. This instrument designed is to be tested experimentally after carrying two and three dimensional computational analysis for Mach number ranging from 0.5 of 3. Also it is designed to fit successfully for 0.3m and 0.6m test section wind tunnel to obtain reasonably merging solution with theoretical and experimental results.
Design of the thrust chamber: dimensional analysis of the combustion chamber and the nozzle of rocket engine using LOX/LCH4 propellants
Authors: Houhou Hatem , Layachi Hemza , Boudjemai Abd Elmajid
Published: January 2020

This paper presents a preliminary dimensional study of small thrust chamber using LOX/LCH4 as propellants. In this study, the mixture ratio of the propellants, the temperature and the pressure at the combustion chamber are used to determinate the geometric parameters of the nozzle and the combustion chamber such as the volume, surfaces, lengths, diameters, etc. our work is based on the most important required output of the propulsion engine which is the thrust force. The results of our work provides the flow areas at the exit of the nozzle and at the throat for different values of the thrust force (10-20-30 KN) and different mixture ratio of the propellants (2.7-2.8-2.9). Moreover, the volume of the combustion chamber is calculated for different proposed characteristic length (80-160-240 cm). Our results offer decisive guidelines for the design of these key parts of the thrust chamber which is required for the design of the whole rocket engine as future work.
Metamorphic tensegrity structure for pipe inspection
Authors: Tantaworrasilp Apicit , Richardson Robert C
Published: January 2020

This paper proposes a new concept of metamorphic tensegrity structure for pipe inspection. A new structural deformation technique is developed that can be employed to design a non-complex and lightweight robot or vehicle. This concept is to deform the cross-shaped tensegrity structure by using the cooperation of prismatic actuators (PAs) and passive joints with locking mechanisms called restrictor mechanisms (RMs). Two control levels are designed to control the structural deformation: A high-level controller for motion patterns and low-level controllers to locally control the PA lengths and restrict the cable lengths of four RMs. Experiments show that the proposed deformation technique can deform the shape and size of the tensegrity structures with the aim of creating a new generation of pipe inspection robots.
Nonlinear control method of electro-hydraulic system driving Two-DOF robot arm with output constraint
Authors: Guo Qing , Liu Yili , Jiang Dan
Published: January 2020

This paper studies tracking control problem for a certain parameter electro-hydraulic system(EHS) to constrain the output cylinder position in prescribed performance. In the control design, a backstepping controller is adopted to guarantee the system stability and the dynamic tracking performance. The dynamic surface control (DSC) is used to eliminate the complexity explosion of virtual control repeatedly derivatives to make the controller and parameter design simple. A barrier Lyapunov function (BLF) is employed in the process of control design to avert the contravention of the time-varying output constraints. The comparative simulation results are given to demonstrate that the effectiveness of the proposed controller. Furthermore the smooth dynamic surface is obtained to guarantee the sufficient stable margin of EHS.
Data processing method in a context-aware system to provide intelligent robot services based on big-data
Authors: Cho Yongseong , Mun Jonghyeok , Park Yoosang , Choi Jongsun , Choi Jaeyoung , Cho Yongyun
Published: January 2020

In order to recognize the situation and to provide robot services based on big data, it is necessary to implement a machine learning model capable of analyzing big data and a method for providing this data to the analysis model for learning. Previous researches have focused on the implementation of various data analysis models to analyze the collected big data. However, in these researches, it is difficult to recognize the new data which is not learned by the analysis model, and further research is needed to solve it. In this paper, we propose a data processing method to provide context-aware information in context-aware system based on big data to provide intelligent robot services. The proposed data processing method can convert the data generated in the domain in which the robot is running to learn data of the machine learning model and provide it, thereby continuously improving the accuracy of the machine learning model. In the experiment, the context-aware information is provided through the prototype of the context-aware system with the proposed method.
Partial soft body robots - a literature review
Authors: Amer Yousef , singh Simranjeet , Doan Linh Thi Truc
Published: January 2020

One of the biggest concerns for every country is to look after their ageing population and provides them a safe life with safe medical equipment and technology. It is estimated that there will increase the ageing of the population in Japan, Western Europe, USA and India with 40%, 30%, 20% and 15%, respectively by the end of the year 2050. Hence, it will create a burden on aged care centres to hire more nursing staff members, which leads to increase the medication cost. One of the feasible solutions to solve this issue is to design the soft robots which will give care to patients at aged care centres. These robots can support patients by providing medicine to them without the assistance of the nursing staff during injury or illness. Therefore, this paper aims to investigate the need of the partial soft robotic arm which can look after patients like robots for interactive body assistance.
Photovoltaic intelligent gas sensors for the detection of acetone concentration over a wide range of measurement for biomedical applications and tasks of public safety
Authors: Vashpanov Yuriy , Son Jung-Young , Heo Gwanghee , Kwack Kae-Dal
Published: January 2020

This report presents experimental studies of electrical changes in photovoltaic sensitive elements based on a Por-Si: c-Si heterojunction during the adsorption of acetone molecules in a mixture of pure nitrogen. The porous silicon layer was formed by electrochemical etching on a p-type silicon wafer. The obtained samples were subjected to additional plasma-chemical treatment using hydrogen and fluoride ions after fabrication. Such surface treatment has a stabilizing effect on the electrical properties of the material and increases their adsorption sensitivity to polar molecules. The developed technology allows you to automatically change the sensitivity of photovoltaic sensors during the experiment, depending on the concentration of acetone. These photovoltaic sensors are able to expand the range of measured concentrations from 1 ppm to 10 vol%.