bluuebunny/crossref_metadata_2025 huggingface dataset:
3 Phase Inverter Switching Algorithm for Industrial Needs
Authors: Syafruddin R , Nataliana D , Hidayat R , Anung  , Mahardika A G , Ramady G D
Published: February 2021

3 phase inverter is needed, besides to change the dc to ac voltage as needed, in the industry every CNC or NC machine needs an inverter to regulate the rotation speed of the motor, constant motor rotation requires for cutting in certain a variety of speeds feeding processes, wherein conventional machines gear is used to change the rotation speed of the motor, here the AC voltage is changed to DC and returned to AC according to the required frequency. For this reason, the researchers tried to research switching the 3 phase inverter algorithm with the principle of space vector pulse wide modulation. Here the switching theory follows the SVPWM switching rule, where the resultant vector is the result of each sector of each phase. The microcontroller accepts the input data, that will be used to generate frequency, the required PWM calculation, the sector, estimates the switching process per sector, the switching sector according to the algorithm results rule. These results will generate inter-phase voltage greater than conventional switching methods, reducing noise, switching steps shorter only 6 steps, improve the power factor. The switching algorithm is ready to be used to make 3 phase inverters.
Implementation of Back Propagation Artificial Neural Network for Heart Disease Abnormality Diagnosis
Authors: Rosa Susila Jaya Kuncara , Afit Muhammad , Laksono Pujo
Published: February 2021

Heart is a very important human organ, where in normal people heart beats at 60-100 beats per second, but there are abnormalities in the heart rate that can occur due to certain causes so that it becomes slower (bradycardia) or faster (tachycardia). Electrical activity of the heart can be detected by an electrocardiogram
(ECG), where the output of this device is a signal that describes the condition of a person’s heart. Artificial neural network (ANN) is one of the learning methods of artificial intelligence that can be used for pattern recognition or the other. One of the ANN learning paradigms is backpropagation where the computation goes through 2 stages, namely advanced calculation and backward calculation. This study aims to simulate backpropagation neural networks to recognize patterns from the output of the electrocardiogram using the MATLAB program. The input is form of printed electrocardiogram recording, and then it is normalized, next the data is processed by backpropagation computing with two phases (training phase and testing phase). The output of this ANN is a description of a patient’s condition whether normal, bradycardia or tachycardia.
Analysis of Water Resources in Irrigation Channels as Kinetic Energy Sources
Authors: Simanjuntak Mangambit Juliandar , Siahaan Yakub , Trimo Didik , Andrew GM , Sardjoe Darmono , Sujana Ahmad
Published: February 2021

Water resources can be utilized for various human needs including household needs, industrial needs, irrigation needs for agriculture as well as potential energy and kinetic energy for electricity generation. Sindupraja Primary / Primary Channels, which are the main canals serving irrigated areas covering 87,803 ha spread across Cirebon Regency and Indramayu Regency, with a water discharge of 10.3 m3 / sec and good discharge capacity and the large dimensions of the channel make it more optimal not to use only as a provider of irigas for agriculture but also as a potential and kinetic energy source for electricity generation. The purpose of this study was to determine the water resources in terms of hydraulics contained in irrigation channels, especially the Sindupraja Main Canal, which can be optimized as a source of kinetic energy. The purpose of irrigation is the use of water that is comprehensive and supports agricultural productivity in order to increase agricultural production, besides optimizing the management of irrigation water resources because there is stored energy namely potential energy (in falling water) and kinetic energy (in running water), where This energy can be used as the main medium to drive turbines and generators as a source of electrical energy. The amount of potential and kinetic energy produced from these water resources depends on the amount of water debit available, the speed of flowing water flow, and the consistency of water discharge in a certain size. Utilizing the potential of water resources contained in irrigation canals, water energy can be used as a source of MHP where kinetic energy contained in the flow of water in irrigation canals is used as a driver of waterwheels, where the waterwheel is used as a medium or means to convert water energy into energy mechanical form of torque on the wheel shaft to produce electrical energy. the amount of power produced depends on the water flow and speed of the water flow.
Characteristics of Porous Asphalt Mixture by Using a Bottom Ash Boiler as a Filler
Authors: Chaira  , Refiyanni M , Azwanda
Published: February 2021

Porous asphalt is asphalt mixture using open gradation dominated by coarse aggregate to produce a large enough cavity. Bottom ash waste produced by a boiler used in the extraction process of palm oil into crude palm oil. Shells and pulps that has been burned at high temperature between 500°C to 700°C will later become of boiler bottom ash. The aim of this study was to inspect the performance of Porous Asphalt Mixture characteristics which combining bottom ash boiler and cement as filler using Retona Blend 55 as a binder. The specimen preparation were designed by the Australian Asphalt Pavement Association (AAPA) method by parameter of Cantabro Loss (CL), Asphalt Flow Down (AFD), Voids In Mix (VIM), Stability and Marshall Quotient (MQ). The Optimum Asphalt Contain (OAC) obtain was used to prepare specimens within OAC with variation 50 % bottom ash boiler and 50 % cement as filler. The result of study showed that the OAC obtained 6%. Almost all parameter values were meet to the required specification of AAPA (2004). The value of CL is 9.25 %, AFD value is 0.19%, Stability 573.27 kg, flow 4.7 mm and VIM 12.29%. The value of VIM not meet to required specification (18%-25%).
Experimental Study of Heat Transfer Using Water – Cooled Condensers to Increase Oil Production from Plastic Waste
Authors: Suryadimal  , Arman Rizky , Sundari Elmi , Darmayanti Yeasy , Efendi Raimon
Published: February 2021

This study aims to determine the performance of the heat exchanger in Low Density Polyethylene non-organic waste refining tools into fuel oil. This research is an experimental study that uses plastic waste obtained from scavengers and then cleaned, dried and chopped with a small size and then inserted into a three condenser level during a certain time. After the combustion temperature rises, water as a cooling medium is flowed in the pipe so that condensation occurs in the oil pipe. The results of the test carried out in the process of cracking plastic waste into fuel oil are affected by time, volume, temperature and heat transfer rate. Testing time for 30 minutes on the condenser obtained the heat transfer rate in the pipe 558.4 W, at 60 minutes the value of heat transfer was 732.2 W, while at 90 minutes the average heat transfer value was 1039.7 W. There was an increase in the heat transfer value as it increased Combustion time and oil produced by the reactor averaged 812 ml.
Analysis of Effect Electric Field Strenght on Safe Distance Below Main Substation Busbar 150 kV
Authors: Yusuf H , Ahkadun N
Published: February 2021

This research is to analyze the effect of electric field strength on the safe distance under the 150kV substation busbar. The research was conducted at 150 kV substation Rancaekek, substation Rancakasumba, substation Cikasungka. The electric field exposure threshold value according to SNI, ICNIRP, IRPA/INIRP and WHO is 10kV / m for the working community. The lowest distance of the busbar conductor to the ground surface is 7.5m. Measurements and calculations of transverse electric field strength from busbar 1 to busbar 2. The height of the test point is 0 m to 2.3 m from the ground surface. From the results of the calculation of the electric field, strength obtained that the shortest minimum safe distance is 7.48 m, while the highest minimum safe distance is 7.88 m. From the results of the measurements of the electric field From the results of measurements of electric field strength obtained that the fastest duration of electric field exposure was 4.42 hours while the longest electric field exposure duration was 5.75 hours. From the calculation of the electric field, strength obtained that: the fastest duration of electric field exposure is 7.56 hours while the longest duration of electric field exposure is 7.91 hours.
Analysis of SOS Results for Engine Lubricants Contaminated by the Fuel in The 3516 TA Diesel Engine Generator Set
Authors: Wilarso  , Domodite Aswin , Sholih Hilman , Mujiarto
Published: February 2021

Generator Set Unit that operates in the PLTD, during operation there is a knocking sound at cylinder position # 14, after checking and removing the injector there is diesel in the combustion chamber and indicated glowing in the exhaust manifold. The purpose of this study is to determine the root causes of knocking and diesel fuel in the combustion chamber. This research method uses oil sample testing to be tested in the laboratory. The results of the analysis of oil contaminated with diesel fuel are caused by diesel oil flowing into the pan oil and after checking the cylinder head crack (groove-shaped) is found on the side of the injector seal holder, when the unit is not operating the diesel flows into the combustion chamber and into the oil reservoir. The groove in the cylinder head is formed, caused by a hard injector seal caused by fuel temperature and high water temperature. The solution of this research is that the pressure on the fuel return from the engine should not exceed 27 kPa, while the maximum fuel temperature is 66 °C (150 °F), and what needs to be done is an improvement of diesel cooling and routine radiator maintenance.
Analysis of Occupational Safety and Health Systems in Bridge Construction Development Logistics Systems: Case Study at Cibeureum Bridge, Sukabumi
Authors: Ichwan N.E , Sutoni Akhmad , Khoerunnisa Siti Tsana , Mujiarto
Published: February 2021

The implementation of the Occupational Safety and Health System in general is still often overlooked. This is indicated by the high number of work accidents that occur. in Indonesia. One of the factors that influence the level of work productivity is the safety and health of workers. Therefore, the application and evaluation of the Occupational Safety and Health System can reduce the level of work accidents. The case study was carried out at the Cibeureum bridge, Sukabumi Segment-3. This study uses qualitative methods, namely by descriptive analysis based on data and observations in the field. The results obtained, the safety and health system has been quite well planned by the company. But there must be an improvement in the planning process in forming a Special Committee on Safety and Occupational Health and Safety Officer. Standards and guidelines used to regulate the implementation of the Occupational Safety and Health System are compiled in an integrated Work Safety Plan from the Contract Quality Plan. This refers to the applicable laws and regulations. Made based on customer requirements. This can be seen based on the existence of commitments and policies, planning, implementation in the construction phase, performance monitoring and evaluation, as well as reviewing and improving the performance of the Occupational Safety and Health System carried out by management.
Machine Learning Sentiment Analysis in Detection System for Rupiah Currency Value Using SysML Language
Authors: Aurachman Rio , Ramadani Luthfi , Utomo Nino Setyo
Published: February 2021

Currency values fluctuate. Some research has tried to find ways to predict the value. One that can be a sign and a trigger for changes in currency values is the people’s sentiment. This paper tries to propose a system and programming script that can predict currency values using sentiment analysis. The system is designed using SysML. The algorithm used is Bag of Words R Programming.
Information System Control and Improvement Process Design based on Clause 8 ISO 20000-1:2018 using SysML Language
Authors: Aurachman Rio , Utama Nur Ichsan , Habibie Jauhari
Published: February 2021

The development of quality information systems has become one of the important strategies in increasing business competitiveness and increasing the added value of products and services. Information systems as a service require a process of continuous improvement. The continuous improvement includes the process of getting feedback for the system’s continuity and then making improvements based on that feedback. Not much research has applied the information system control process based on ISO 20000-1: 2018. This research tries to propose this.
Technology-based education
Authors: Friyanto A , Prasetyo I , Albar C N
Published: February 2021

This study aims to determine the benefits of technology and the opportunity to do business in the world of education. To analyze the data, this research used descriptive and quantitative methods, namely descripting the data in a subjective and objective form of words and images. The results of the study showed that technology plays a very important role in education because it is very helpful in improving knowledge when students do not have or cannot contact their supervisor/teacher. This study concludes that in the world of education, it cannot be denied that efficient and effective learning process information technology is needed at this time. Therefore, the opportunity to start an Education Technology business is very promising because it is considered efficient and effective.
Grafting of Maleic Anhydride onto Cyclized Natural Rubber in the Melt Phase: the Effect of Trimethylol Propane Triacrylate
Authors: Said Siregar M , Ardilla Desi , Eddiyanto  , Nasution Asmara Sari
Published: February 2021

The grafting product of maleic anhydride onto cyclizednatural rubber have been produced in the presence of trimethylol propane triacrylatecomonomer which is processed in an internal mixer 150°C 80 rpm. In this research, the ratio of Tris / maleic anhydride used is 1: 2; 1: 1 and 2: 1.All grafted product was purified to determine the degree of grafting for each graft product by the titration method. The degree of grafting increases with increasing trimethylol propane triacrylate mole ratio. The highest degree of grafting is obtained in moles ratio of 2: 1 which is to 5.88%.
Minimize waste on production process using lean concept
Authors: Dewi SK , Utama D M , Rohman R N
Published: February 2021

This research aims to analyze and minimize the waste that occurs in the production process by using a lean production approach. One of the factors that can influence ineffective and inefficient in the production process is waste in the production process. An effective and efficient pr oduction process will support the company to increase productivity. The problems that occur in company X are companies that still often experience delays in meeting consumer demand, and there are still defect products. These problems have to be solved. One approach is to incorporate lean principles in the production process. From the results of the analysis, activity mapping obtained the value-added activity (VA) has the lowest percentage of 13.60% and non-value-added activities (NVA) has a percentage of 59.80%, which cause of delay. Solution to minimize waste are improve inspection process, scheduling maintenance, make standard operation procedure and reduce set up time.
Flow visualization analysis on the vertical axis Savonius water turbine by placing a cylinder in front of returning by varying stagger angle
Authors: Setiawan P A , Yuwono T , Widodo W A
Published: February 2021

This work will investigate the effect of the circular cylinders distance variation perpendicular the free stream installed in front of the returning to increase the turbine performance. Computational Fluid Dynamics using Gambit 2.2.30 software and ANSYS 17.0 software has been used to solve the incompressible URANS. Numerical model is validated towards experimental data at TSR 1.078. The working fluid is in verification using air at Reynolds of 4.32 x105. The ds/D is 0.5 at gap (S/D) of 0.95 with varying stagger angle of 0°, 30°, 60° and 90° with TSR of 0.3, 0.5, 0.7, 0.9, 1.1 and 1.3. The change of the stagger angle increase the turbine performance at a stagger angle of 60° followed by the increase of pressure in front side and reduce of the back of blade. In addition, stagger angle of 0° influences a circular cylinder become blockage and decrease the performance.
Computer Modelling of the Information Properties of Hyper Chaotic Lorenz System and Its Application in Secure Communication System
Authors: Rusyn Volodymyr , Mujiarto  , Mamat Mustafa , Azharul Firmansyah , Mada Sanjaya W. S. , Sambas Aceng , Dwipriyoko Estiyan , Sutoni Akhmad
Published: February 2021

This paper presents computer modeling, analysis and research of the hyper-chaotic Lorenz system based on programming interface that has been developed in LabView software environment. This study allows for generating and research of the main information properties of hyper-chaotic Lorenz system, focusing on time distribution of the four chaotic coordinates, phase portraits and Lyapunov exponents. The programming interface demonstrates the algorithm of masking and decrypt of the information carrier.
The Role of Farmers Readiness in the Sustainable Palm Oil Industry
Authors: Apriyanto M , Partini  , Mardesci H , Syahrantau G , Yulianti
Published: February 2021

One effort currently made by the Indonesian government to ensure the sustainability of the development of the palm oil industry is to create a sustainability standard called Indonesian Sustainable Palm Oil (ISPO) in presidential regulation no 44 in 2020. The purpose of this study is to determine the value of the ability of independent coconut farmers palm oil in Indragiri Hilir to meet the Indonesian Sustainable Palm Oil (ISPO) standards and identify the problems faced in achieving these standards. Evaluation of the ability of independent smallholders to achieve ISPO standards is carried out by an audit method, the results of the assessment of all parameters set in accordance with the Principles, Criteria and Inductors. The Criteria and Indicators contained in the ISPO provisions are then assessed in percent. The audit method is carried out in a quantitative descriptive analysis of the appropriateness of ISPO principles, criteria and indicators by comparing the implementation of legality, organization and management, management and environmental monitoring implemented by independent smallholders. Readiness of ISPO application for smallholder farmers by evaluating four principles, 20 criteria and 47 indicators. Of the 47 indicators determined in the ISPO requirement for self-help patterns, as many as 58.94% of the ISPO indicators have never been implemented by independent smallholders and 42.06% of the ISPO indicators have farmers running them. From ISPO indicators that have been carried out by independent smallholders, only a small portion of independent smallholders are run.
The Effect of Modern Dressing Using Mix Cadexomer Iodine Hydrogel on Wound Healing Process in WCC Pati
Authors: Hartinah Dewi , Hartotok  , Yusuf Effendy
Published: February 2021

Diabetes mellitus is a chronic metabolic disorder due to the pancreas not producing enough insulin or the body cannot use insulin produced effectively. The purpose of this study was to determine whether there is an effect of modern dressing using cadexomer iodine hydrogel mix on the process of DM wound healing in WCC Pati. This type of research uses quasy-experiment with pre-test post test control group design. The sample of this study was 22 people, data collection using the Bates Jansen Wound Assessment Tool. Analysis using the Mann Whitney U Test statistical test. The results of the study showed that the p value of the intervention group was smaller than the p value of the control group so that the administration of the cadexomer iodine mix hydrogel was more influential in the process of DM wound healing compared to the control group that was only given the hydrogel.
Operational Risk Analysis at Agribusiness and Technology Park (ATP) IPB, Bogor, Indonesia
Authors: Fauzi Aditra M. , Nurhayati Popong , Jahroh Siti
Published: February 2021

ATP IPB is an autonomous business unit under Teaching Farm Sub Directorate of IPB’s Business and Entrepreneurship Development Directorate. It produces fruits and vegetables from its own farm and farmers as its partners, and also sells the produces mainly to modern markets. It faces risks in operating its business, especially operational risk. This study aims to: (1) identify ATP operational risk, (2) measure risk based on likelihood and impact, (3) analyze the root causes of ATP operational risk, and (4) provide alternative solutions to the underlying causes. The study was conducted in January to April 2019. Risk level map, risk map, and cause-effect diagram were employed in this study. Results showed three main risks, namely (R1) the output of ATP’s partner did not reach the target, (R2) the output of ATP’s partner exceeded the target, and (R3) the farmer’s production did not reach ATP standard. Risk R2 is included in the low risk level, risks R1 and R3 are included in the extreme risk level. The root causes of the three risks are ineffective penalties, no priority for the screen-house, no priority for increasing the workforce, relationship between supervisor and partner farmers are still transactional. Alternative solutions that can be proposed are participatory assistance, contract review, screen-house implementation, and the formation of farmer groups.\
Analysis on the dislocation of GaN on different substrate
Authors: Chen Yilun
Published: February 2021

Though there are still disputes on whether the threading dislocation density (TDD), to produce high quality Gallium Nitride ( GaN ) with low TDD is needed. In this passage, we would first show the impact of dislocation and review the latest methods to reduce dislocation on Si, GaN, and sapphire. The Si substrating with serpentine channels could produce GaN by using Si substrate with low density dislocations. The method that use the markless-3D provides a new way to reduce the dislocation from big off-angle. The multiple-step growth technique controls the conditions of crystallization and use two steps of crystallizing to grow with both low dislocation density and 2D growth shape. The last method is to use the Na-flux method to exclude cracks with sapphire in crystal.
Research on the time delay law of water-aluminium alloy interface based on ultrasonic phased array technology
Authors: Wang Yajun , Li Guoping , Wu Xianglong
Published: February 2021

Based on the ultrasonic phased array technology, the time delay law of ultrasonic deflection and focusing at the water-aluminium alloy interface is studied in this paper. By changing the delay time applied on each array element, the immersion ultrasonic phased array technology can realize the preset deflection angle and focusing depth, so as to detect different angles and depth positions of the work piece. The principles of ultrasonic phased array deflection and focusing are studied based on Huygens principle, and the time delay law is obtained when the sound beam is deflected and focused. When ultrasonic waves deflect and focus at the water-aluminium alloy interface, the Matlab software is used to simulate the time delay law and sound field distribution, which verifies the correctness of the design and calculation of the time delay law.
Design of Torque Motor Characteristic Test System
Authors: Zhang Huajin , Lin Fan , Zhang Xin , Wen Xianghua
Published: February 2021

The steering gear is an important part of the guided missile control system and the actuator of the flight control system. The torque motor is one of the key components of the steering gear. Its performance directly affects the performance of the steering gear and directly determines the dynamic quality of the guided missile during flight. According to the composition and working principle of the torque motor, to judge its performance, the no-load angular displacement characteristics and pressure characteristics of the torque motor should be tested. In order to accurately and quickly measure the performance of the torque motor under working conditions, the design of the torque motor test system is realized based on the virtual instrument development software. The test system mainly includes two parts: a hardware platform and a human-computer interaction interface. The hardware platform mainly includes an industrial computer, a torque motor test bench, a control box and a data acquisition card. The human-computer interaction interface has the functions of test parameter setting, data acquisition, data processing, data storage and form printing. The torque motor test system has the advantages of small prototype size, convenient operation and accurate test results. The test results show that the test method of the test system is reasonable, the test system runs reliably, the test efficiency is high, it can carry out stable and real-time data collection and processing, is easy to operate and maintain, and meets the key requirements of torque motor testing.
Pilot’s mental workload nonlinear correlation among objective and subjective measurements
Authors: Alaimo A , Esposito A , Orlando C
Published: February 2021

In the aviation framework, the workload evaluation is influenced by human factors effects both for pilots and ground operators. Nevertheless, the measurement of workload is of great importance to prevent human errors due to fatigue. In the present work, correlation analysis has been carried out to investigates the relationship between subjective and objective workload measurements. An experimental campaign was conducted using a full flight business aircraft simulator. Particular attention has been paid to the NASA-TLX subscales contribute. In terms of objective measurements, three different indexes gathered from heart rate variability have been considered. As the main result, the frequency-domain index reveals a large correlation effect with the workload subscale for the maneuvers taken into account.
Free-drop simulation and analysis of Full-screen smartphone based on ABAQUS/CAE
Authors: Cao Zhong , Li Weijie , Chen Zhuo , Wang Feng , Shang Wenli
Published: February 2021

Finite element analysis (FEA) provides numerical modeling and testing methods of stress analysis for products. The time of products development cycle can be shorten and the cost for products physical testing can be reduced with FEA. Drop test is one of the important tools uses for the impact behaviour study of cell phones, which identifies weak design points during the impact behaviour of cell phone. With the development of technology and growing of people’s demand, the screen of cell phone is getting bigger and bigger. Full-screen smartphones have become a trend. It is necessary that modeling and analyzing for full-screen smartphones are considered. This study conducts free-drop simulation and analysis on full-screen smartphones based on ABAQUS/CAE.
Dynamics of the movement of the descent vehicle in the atmosphere of Mars with the use of inflatable brakes in the lower atmosphere
Authors: Chen Danhe , Richier Léo , Koryanov Vsevolod V
Published: February 2021

Currently, more and more spacecrafts are being designed, to explore the planets of the solar system. One of the very important stages in the execution of such missions is the movement from the moment of deorbiting until the moment of approaching the surface. The entire descent trajectory from the moment of separation to contact with the surface is a very important stage and a very important object of research particularly in the field of Computational Fluid Dynamics (CFD). It is to this process that a series of articles by the authors is devoted. This article is devoted to the movement of the descent vehicle in the lower atmosphere. Some parameters of the descent vehicle movement at this stage of movement are analyzed. The importance of such research and the possibility of using inflatable braking devices are shown.
Heat transfer enhancement mechanism of jet impingement on aeroengine curved surface using large eddy simulation
Authors: Li Qin , Dong Wei , Cai Xuecheng , Yang Xiaofeng , Zheng Haoran
Published: February 2021

Jet impingement is widely used in anti-icing and de-icing of aeroengines. To improve the efficiency of anti-icing and de-icing, heat transfer in jet impingement flow should be further enhanced. By using large eddy simulation (LES) method, jet impingement flow was analysed in time-domain and spatial-domain. It was revealed that the jet flow has quasi-periodic characteristics in time, and heat transfer is dominated by vortex structure. In addition, the impinged surface curvature has a certain influence on the spatial distribution of Nusselt number. Better heat transfer effect can be achieved by inducing more vortices and applying proper surface curvature.
Overview of surfing aircraft vortices for energy
Authors: Zhao Yixin , Wu Hanyu , Zhang Qiang , Cheng Qing
Published: February 2021

Surfing Aircraft Vortices for Energy (SAVE) refers to the behavior that an aircraft “rides” on the vortex of the front aircraft just like the formation flying of migratory birds and it can also provide guidance for the aircraft that is difficult to avoid entering the front vortex, reduce the incidence of flight accidents caused by the vortex, and improve the safe operation ability of civil aviation. The technology has the advantages of saving energy and increasing range, which is a hot issue in the field of aviation research. Firstly, this paper analyzes the main research contents, technological developments and applications in the field of SAVE at home and abroad. Then discusses the key technologies of SAVE such as aerodynamic principles, control of SAVE, safety guarantee, path planning, and related experimental verification technologies. Finally, the development and application trend of SAVE technology in military and civil aviation fields and its corresponding benefits brought by it will be pointed out.
Study on a quality assessment method for rocket body structure based on product quality DNA
Authors: Jiayu Yao , Haijiang Liu
Published: February 2021

Under the current production mode of multiple varieties and small batches, the traditional post-event quality assessment method is still used in the manufacture of rocket body structure in China. In order to solve the problem that this method can not fully reflect the quality of each step in each process, a quality assessment method for rocket body structure based on product quality DNA is proposed in this paper, which converts the assessment of product quality into the analysis of product quality DNA. This method comprehensively assesses the quality of each process and each step in each process by searching the assessment knowledge base based on product quality DNA. Based on the principle of biological DNA, this paper combines the idea of product gene with product quality, and constructs a model of product quality DNA from three structural levels(basic structure, double helix structure and superhelix structure). This paper takes a weld of a rocket body structure as an example and assesses the quality of this weld by using the quality assessment method for rocket body structure based on product quality DNA. The results show that the quality of the weld is assessed as “good”.
A Review of High Precision Finite Element Modelling Methods for Light and Small UAS
Authors: Yongjie Zhang , Yingjie Huang , Kang Cao , Yafeng Wang , Yazhou Guo , Jizhen Wang , Xiaochuan Liu
Published: February 2021

In the dynamic mechanics analysis of light and small unmanned aerial systems (UAS), The importance of the high-precision modelling of UAS is unquestionable. Modelling can be classified into 3D geometric model modelling and finite element model modelling, of which the finite element model modelling is mainly divided into four parts: discretization, connection modelling, contact modelling and material attribute definition. This review summarizes the existing modelling methods of light and small UAS, and provides the basic methods and modelling methods for the simulation calculation of light and small UAS. Implications for practice and future research are provided.
Improved weighted NND scheme for shock-capturing
Authors: Li Chen , Chen Jianqiang , Yuan Xianxu , Liu Pengxin , Sun Dong , Qilong Guo
Published: February 2021

Aimed at decreasing the numerical dissipation of weighted non-oscillatory and non-free-parameter dissipation (WNND) scheme, we present an improved counterpart for shock-capturing. The new algorithm is based on the framework of Z-type weighting procedure with new local and global smoothness indicators. The performances of the proposed scheme are evaluated on several numerical tests governed by one-dimensional Euler equations. Numerical results indicate that the improved WNND scheme has advantages over the original WNND and third-order WENO-JS and WENO-Z schemes.
Application of colour fluorescent oil flow visualization for a high speed cavity
Authors: He Binhua , Li Guoshuai , Zhou Fangqi , Liu Dawei , Xiang Xie
Published: February 2021

For studying the complex flow structure of a high speed cavity, including shear layer, separation, reattachment and vortex, the single-color fluorescent oil flow visualization system in the 0.6m×0.6m trisonic wind tunnel of China Aerodynamic Research Development Centre was enhanced. Different portions of the cavity such as its bottom wall, left and right side walls, front and rear walls and area outside the cavity utilized different oil films with different fluorescent particles to visualize the flow mixing more effectively in the cavity. Specialized ultraviolet light sources are used to enhance the oil flow image contrast. Additionally, to ensure the oil film follows the surface streamlines and indicates the skin friction lines more accurately, the thickness and viscosity of the oil film are well controlled. A high-speed cavity wind tunnel test was conducted to validate the improved oil flow visualization system at Mach number ranging from 0.6 to 2.0. The experimental result shows that the improved oil flow system can effectively visualize complex flow patterns of the cavity flow at all Mach numbers. Colour fluorescent oil flow visualization system established in the present study provides a capability to visualize the flow mixing phenomenon in cavity flows with a high image contrast.
Investigation on the depth effects of the micro-grooves on the suppression of the second modes in the hypersonic boundary layer
Authors: Guo Qilong , Li Chen , Tu Guohua , Chen Jianqiang , Wan Bingbing , Liu Yong
Published: February 2021

The transition of the hypersonic boundary layer and the corresponding control have been extensively interested since the strong engineer background. In the present work, a hypersonic boundary layer over a flat plate of Mach 6 is computed using the high-order finite-difference scheme. The influences of the two-dimensional micro-grooves on the evolution of the second-mode instability wave are investigated. The comparison is carried out between different depths of the micro-groove. The results indicate that the actual control effect does not significantly vary with the depths under the condition with large grooves. The DNS prediction show different results with the theoretical model for the acoustic reflection coefficient. It is suggested that new model should be derived to guide the design and optimize of the parameters of the micro-groove.
Research on parameter adjustment method of servo controller based on genetic algorithm
Authors: Tian Huan , Dong Wenyong , Xu Yafen , Gao Yuan , Fang Cheng
Published: February 2021

In view of the problem that the controller parameters of the servo system of launch vehicle cannot be adjusted after installation, the parameter adjustment method of the servo system controller parameters is designed by the optimization method based on the genetic algorithm. Set the scale, the notch frequency and the damping coefficient as the variable to be adjusted. The adjusted ITAE guideline module is the error criterion, and the notch filter parameters are adjusted. The experimental verification results of servo system simulation test bench show that the method of this paper can effectively optimize the parameters of servo system controller and improve the quality of servo system.
Thrust control when landing a ship-based aircraft
Authors: Semakov Sergei
Published: February 2021

We consider a landing on an aircraft carrier. We propose a scheme for calculating the probability of go-around due to disengaging the arresting gear and a scheme for calculating the maximum descent of the aircraft trajectory with respect to the deck level immediately after leaving the deck. The main control parameter is the moment of increase in aircraft’s thrust before touching the deck. The requirements imposed on the probability of go-around and the maximum descent of the aircraft trajectory determine the possible range for the moment of increase in aircraft’s thrust. Proposing the scheme for calculating the probability of go-around, we use our previously obtained results related to finding the probability of a successful aircraft landing. We present the numerical results for the real aircraft when landing on the real aircraft carrier.
Simulation and analysis of multi-frequency signal superposition with scattering center model
Authors: Yang R P , Wang X , Liu C H , Liu Y , Liu Y
Published: February 2021

In this paper, the superposition of time domain scattering signal with different frequency is analyzed. Simulation results shows that the peak value of the sum signal is able to be approximately estimated from scattering center model. Besides, the results show that energy of multi-frequency scattering signal has the potential to accumulate in time domain, which might help to design new kinds of signal to recognize target and resist noise at the same time.
Simulation detection based on single photon quantum key distribution protocol
Authors: Liu X N , Hu C C , Yin M J , Jin L
Published: February 2021

With the continuous development of quantum communication in recent years, quantum key distribution (QKD) has also become a key technology in the field of quantum communication. Due to the limitation of physical resources and experimental conditions, the effectiveness of different communication protocols cannot be accurately analyzed. To solve this problem, a protocol simulation method is proposed, BB84 and B92 protocols are simulated and analyzed on a classic computer by this method. On the Eclipse IDE Developers platform, the simulation program of the quantum communication protocol was written using Java language, the simulation process under the ideal environment and the eavesdropping environment was analyzed with emphasis. The simulation results show that the key distribution efficiency of BB84 is about 50% without eavesdroppers, which is much higher than 25% of B92, and the key distribution efficiency under eavesdropping conditions is about 25% and 18%. The experimental results are consistent with theoretical expectations, verifying the correctness of the protocol simulation, and also proving the feasibility of using computers for quantum communication protocol simulation.
Effect of interleaving on the performances of the MAP turbo decoder controlled by the IHDA and CE Stopping criteria
Authors: Ouardi Aissa
Published: February 2021

In this article, we present the effect of interleaver size on the performance of a turbo decoder using a stopping criterion to reduce complexity and decoding time. We choose the two criteria CE and IHDA. The interleavers used are pseudo-random interleavers, S-Random, of sizes 5120 and 1280. The simulation results show that the IHDA criterion uses the lowest average iteration number in medium and high Signal-to-Noise Ratios SNR. Increasing the size of the interleaver also provides significant coding gain
DOA estimation based on fractional low-order multi-sensor time-frequency analysis in heavy tailed noise
Authors: Xu Jing , Sun Bin , Cao Yang , Hong Wei
Published: February 2021

In order to improve the performance of Direction-of-arrival (DOA) estimation in heavy-tailed noise, a novel DOA estimation method based on fractional low-order multi-sensor time-frequency distribution is proposed. We first use the high-resolution of the fractional low-order multi-sensor time-frequency analysis (FLOM-MTFA) to obtain the time-frequency matrices of the array signal. Then, the high-energy points of the fractional low-order multi-sensor time-frequency matrices is selected to improve the MSNR. We finally compute the averaged FLOM-MTFA matrix and exploit estimation signal parameter via rotational invariance techniques to estimate DOA. Theoretical analysis and simulation results show that the proposed method can effectively estimate DOA in heavy tailed noise.
Research on key technologies for 2μm band of thulium-doped fiber laser
Authors: Zhang Ning , Sun Huijuan , Luo Yang
Published: February 2021

Abstract The gain material of 2μm wavelength thulium-doped fiber laser is a thulium-doped fiber doped with rare earth element thulium. Rare earth doped optical fiber as gain medium is the basic structure of optical fiber laser. This type of laser is mainly composed of pump source, coupler, gain optical fiber doped with rare earth elements, cavity and other optical devices. The pump source is generally a combination of one or several high-power laser diodes. The light emitted by the pump source enters the gain optical fiber doped with rare earth elements through a certain pumping mode. The inversion of the number of particles occurs when the doped optical fibers absorb photons, and then the light waves stimulated from the doped optical fibers are emitted by the laser after the oscillation. Since the connection structure and parameters between optical fibers and optical components can be maintained stable over a long period of time, thulium-doped lasers do not need to be maintained regularly and are based on output power. They have smaller volume and weight, lighter weight and longer life than solid-state lasers. However, in general, the power of a 2μm wavelength thumbium-doped fiber laser is not too high, while a high-power 2μm wavelength thumbium-doped fiber laser can meet people’s needs and play a greater role. Therefore, improving the power of 2μm wavelength thumbium-doped fiber laser is an important direction for the development of thumbium-doped fiber laser. The energy level structure of thulium ion is analyzed, the doping concentration of thulium ion is studied, and the method to increase the power of a 2μm wavelength thulium-doped fiber laser is given.
A novel recommendation algorithm with knowledge graph
Authors: Liu L , Zhang P
Published: February 2021

Personalized recommendation is an important topic in recommendation algorithm research. Traditional collaborative filtering recommendation algorithms suffer the sparseness and cold start problems. Existing knowledge graph based recommendation algorithms miss the high-order similarity at the subgraph level. This paper introduces a RNN-based distributed representation model of knowledge graph called KG-GRU, which uses a sequence containing nodes and relationships to model the subgraph similarity in the same embedded vector space. Then, a personalized recommendation algorithm based on knowledge graph called KG-GRU4Rec, is proposed. KG-GRU4Rec implements an end-to-end predictive user rating model. Experimental results demonstrate that KG-GRU learns more accurate knowledge about entities and relationships in the graph and KG-GRU4Rec outperforms the comparison algorithm in both hit ratio and average reciprocal ranking.
Toward secure refactoring of object-oriented programs
Authors: Mahmoud Marwan
Published: February 2021

Security is a significant issue in software systems. The initially secure design of a software system could be at risk of a refactoring transformation. Consequently, via a refactoring transformation, the software could be considered vulnerable, and the refactoring process can undergo security-aware refactoring. This work deals with three security approaches to assist programmers in refactoring their software systems while simultaneously sustaining or possibly improving the security of their software system. In addition, this work deals with security-aware refactoring at the design stage rather than refactoring that requires a full source code. The main aim of this work is to provide programmers with knowledge about secure refactoring processes to improve the long-term maintainability of the software system in a secure way while sustaining the external behavior of the system.
Numerical Simulation of the Fracture Characteristics of Copper EFP with Different Constitutive Models
Authors: Ding Li , Jiang Jianwei , Men Jianbing , Wang Shuyou
Published: February 2021

With three different constitutive model, LS-DYNA hydro code is applied to simulate the forming and fracture characteristics of Copper EFP. By comparison of numerical results of different models, the appropriate constitutive model to simulate the complete and fracture EFPs can be obtained. By comparison of experimental and numerical results, it can be concluded that Steinberg-Guinan constitutive model gives the best result to predict the complete EFP’s forming shape with minimum error, while Johnson-Cook constitutive model with failure model and h-adaptive algorithm is the most suitable method to predict the fracture of EFP in axial direction. The research results are important and significant in the deign of shaped charge, which could provide a guideline to predict the fracture of EFP in numerical simulation.
The Realization of Baking Technology in Virtual Simulation
Authors: Zeng Min
Published: February 2021

In the application of virtual simulation, the fluency of real-time rendering directly affects the quality of works. As developers and designers, we always try our best to reduce the computation of real-time rendering. Baking is one of the commonly used techniques for system
Model and Empirical Research on Risk Assessment Based on Second-Order Monte Carlo Simulation
Authors: Gao Xiaohong , Liu Jian
Published: February 2021

First order Monte Carlo simulation simplifies the processing of input variables, while the analysis results can not meet the needs of major decisions. Second order Monte Carlo simulation divides the input variables into uncertainty and variability, which can help decision makers understand the impact of different input variables on the results and the credibility of the evaluation results. On the basic of analysing the two methods, an enterprise’s investment project was taken as an example; using point estimation method, first-order Monte Carlo simulation and second-order Monte Carlo methods respectively for risk assessment and comparison. Finally, conclusions and recommendations are given for using second-order Monte Carlo simulation for risk assessment of Investment Project Decision-making.
Ternary Sentiment Classification of Airline Passengers’ Twitter Text Based on BERT
Authors: Xie Yungao , Wen Hong , Yang Qing
Published: February 2021

Traditional word vector generation model cannot solve the polysemy problem of word representation in Twitter text, so, a method is presented here, firstly, by using Bidirectional Encoder Representations from Transformers (BERT), the semantic feature vector of the text can be obtained, and then, the feature vector is inputted into the Softmax classifier to implement the sentiment classification of Twitter text. The experimental datasets are source from passengers’ Twitter comments of USA six airlines, the sentiment classification model based on Embeddings from Language Model (ELMo) as the experimental control group. The experimental results indicate that the proposed model is advantage over the experimental control group by using F1-score as the evaluation index.