bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple Tight Performance Bound Based on the GFBT for Binary Linear Codes
Authors: Liu Jia , Zhang Mingyu , Chen Rongjun , Wang Chaoyong , An Xiaofeng , Wang Yufei 
Published: January 2020

Abstract
A simple tight upper bound, without any integral and optimal operations in its final version, is proposed over additive white Gaussian noise (AWGN) channels. We derive the simple bound both on the frame probability and on the bit error probability. The proposed bound is within the framework of Gallager’s first bounding technique (GFBT), in which the Gallager region is chosen by the hamming distance, avoiding the limitation of the Euclidean distance. To compute the upper bound inside the Gallager region, we can tighten the union bound not only by collecting more information about the receiving vector which can cause the maximum-likelihood (ML) decoding error events, but also by employing the independence between the ML decoding error events and some positions of the received vectors. The proposed bound is tight since numerical results show that it is tighter than the proposed bound by Divsalar (without any integral and optimal operations) and the proposed bound by Poltyrev (considered as one of the tightest upper bounds for the binary linear codes with lower rate).
Dynamic Priority Assignment Algorithm Based on Multi-Elements in Vehicular Ad-Hoc Network
Authors: Meng Fudong , Tian Jin 
Published: January 2020

Abstract
In Vehicular Ad-hoc Network, different messages have different degrees of urgency and have specific requirements on delay and reliability. In this paper, we propose a dynamic priority assignment algorithm based on multi-elements to adapt to the dynamic changes of vehicles and transmit messages in an accurately and orderly manner. A priority is assigned to each message based on static and dynamic factors and size of the message. After a detailed analysis of the allocated priorities, the results show that the algorithm we conceived can quickly and accurately allocate the priority for different kinds of messages based on the characteristics and requirements of them.
Development of Large-Range Dynamic Three-Component Sensor
Authors: Chai Jixin , Chen Kexing , Zhao Yinming , Xu Jian , Fan Xiaoyan 
Published: January 2020

Abstract
Currently, the vast majority of sensor applied in the field of dynamic testing is piezoelectric sensor, Piezoelectric sensors over 200t are very difficult to produce, However, the traditional strain sensor is not suitable for dynamic testing due to its insufficient frequency response, The large-range strain type dynamic three-component force sensor developed in this paper has been successfully applied in high-speed rail collision test experiment, which breaks the monopoly of piezoelectric sensor in the field of dynamic test and has a broad application prospect.
Temporal and Spatial Distribution of Multi-scale Drought in North China
Authors: Zhou Kai , Wang Yimin 
Published: January 2020

Abstract
The North China is located in the East Asian monsoon region. The uneven spatial and temporal distribution of water resources leads to frequent drought disasters, and drought has increasingly become a limiting factor for regional development. In this paper, the intrinsic evolution characteristics of multi-scale spatial and temporal distribution of meteorological drought in the past 57 years in North China are analyzed by using standardized precipitation evapotranspiration index and ensemble empirical mode decomposition with multi-time scale features. The results show that the North China region was generally humid in the 1960s and 1970s. Drought in the 1980s and 1990s increased relatively. The interannual SPEI of North China changed in 1991, and entered a relatively dry period in the late 1990s and 2000s. From the SPEI index sequence, the scale characteristics of each scale were extracted. It was found that the SPEI sequence of the three-month time scale in North China mainly existed in the three scale ranges of monthly, interannual and intergenerational, At the same time, through the comparison of the temporal and spatial distribution characteristics of the summer drought in june and august 2002 in North China, it was found that the severe drought in august 2002 was caused by the temporal and spatial overlap of short-term scale and long-term drought events.
Research on the Construction of Global Spatial Multi-Grid Model Considering the Geographic Features of China
Authors: Zhang Yongzhi , Zhang Keqi , Ye Xinyang , Wang Wei , Li Huafeng 
Published: January 2020

Abstract
According to the subdivision principles of global grid, the advantages and disadvantages of classical spherical grid generation method at home and abroad are analyzed and compared. Considered with the spatial characteristics of China and the current standards of Geographical data, this paper proposes a global spatial multi-grid subdivision method that could adapt to the characteristics of global space and take into account the geographical features of China. And on the basis of this, a global unified spatial multi-grid coding model has been established and the corresponding neighborhood search algorithm and coordinate transformation formula have been derived, which provided theoretical supports for global grid positioning and information sharing.
Simulation Design of Reconfigurable Multifrequency Yagi Antenna
Authors: Zhao Lili , Yu Pengpeng , Zhou Xinsheng , Dong Qicai , Wang Ziru , Li Haiyan , Su Lina 
Published: January 2020

Abstract
In order to reduce the operating cost and improve the benefits of communication system, it is a feasible scheme to reduce the number of antennas used while ensuring the communication quality. Because reconfigurable antenna has the characteristic of automatically changing a certain electrical characteristic parameter, it has become one of the hotspots in antenna research. In the design of this paper, reconfigurable antenna is realized by changing the working state of PIN diodes embedded in external feed matching network. The design of Yagi antenna is introduced below.
The Performance of One-Way Clutch in a Cam-Based Infinitely Variable Transmission
Authors: Al-Hamood Amjad , Jamali Hazim U , Abdullah Oday I , Schlattmann J 
Published: January 2020

Abstract
Continuously variable transmission is the system which provides a step-less change in transmission ratio between two rotating shafts. When it can provide zero ratio, it is known as infinitely variable transmission (IVT). These systems are mainly classified into two categories; traction and non-traction types. In the traction type, the power is transmitted by friction force that develops between the active elements in the mechanism, while in the non-traction systems, the power is transmitted via direct contact. A very common type of non-traction IVT is the cam-based system. In this type, the rotating motion of the input element is converted to oscillatory motion with continuously variable amplitude. Eventually, the oscillatory motion is rectified to one-way rotational motion by means of a one-way clutch (rectifier). The rectifier is considered an essential element in the IVT system, as it is subjected to an extreme dynamical condition. In this study, the performance of one-way clutches (rectifiers) in a cam-based IVT is presented. The IVT system under consideration is a combination of two identical units and in each one, a rectifier is fitted at the output shaft. It is required that this rectifier is able to efficiently transmit the power during its engagement. It should also generate minimal power loss during disengagements, when aggressive relative motion is presented between its parts. It has been found that the operation of the one-way clutch is mainly determined by the designed cam profile. For this study, the profile is a combination of constant speed and trapezoidal forms. It was also concluded that the value of the selected transmission ratio controls the amount of fluctuation in the acceleration, velocity and displacement and hence, the energy lost due to slippage of the clutches.
Multi-Response Optimization of Mechanical Properties of Al reinforced by Al2O3 and/or SiC using Grey Relational Analysis
Authors: Hlail Haneen Hameed , Al-Shafaie Saad Hameed 
Published: January 2020

Abstract
Metal matrix composites (MMCs) combine attractive characteristics of ceramics and metals. Al-hybrid composites are a recent generation of MMCs and have the potential to satisfy new demands in advanced engineering applications. In this work, Al-MMC has been fabricated by mixing various percentages of Al2O3 and/or SiC reinforcement into the Al alloy, using stir casting. The mechanical properties (hardness, yield strength, tensile strength, elongation and flexural strength) have been measured for the fabricated MMCs. Grey relational analysis (GRA), based on the Taguchi method, is applied using three factors Al2O3, SiC and Al2O3 + SiC with three levels. Results show that the all reinforcement materials have a significant influence on the response. Results also show that the Taguchi-based grey relational approach improved the properties of output response of hybrid MMC.
Selection of Suitable Precipitation CMIP-5 Sets of GCMs for Iraq Using a Symmetrical Uncertainty Filter
Authors: Khayyun Thair S , Alwan Imzahim A , Hayder Ali M 
Published: January 2020

Abstract
Prediction of future water resources in Iraq for the period 2020 to 2100 based on different scenarios of climatic change models by harnessing many calibrated Arc-SWAT models needs to select future precipitation data from suitable sources. Therefore, the selection of the appropriate source of the possible future precipitation time series data sets was studied by examining 20 models of the fifth phase of the Coupled Model Inter-comparison Project (CMIP-5.0) for General Circulation Models (GCMs). The Symmetrical Uncertainty (SU) approach was used to determine the performance of the 20 CMIP-5.0 sets of GCMs against a monthly scale of historical precipitation datasets at each one of 35 rain gauge stations spread throughout Iraq, and an appropriate ensemble of GCMs selected. The examined models were ranked as 1st, 2nd, 3rd, etc. based on the SU values at each station and the final ranking of the models was carried out using a multi-criteria decision-making (MCDM) method. The results showed that the HadGEM2-AO and HadGEM2-ES were the best (1st ranked) models at 31 stations, while the MIROC-5 and CSIRO-Mk-3.6 were the best models at Zakho and Duhok stations, respectively, and the BCC.CSM1.1.m and FIO.ESM were the best models at Samarra and Hilla stations, respectively. There was a variation in simulation preference regionally between the two models HadGEM2-AO and HadGEM2-ES in the second ranking except at Tel-Afer and Najaf stations. No predominant models were found in other ranks throughout Iraq. The results of the final ranking of these 20 CMIP-5 sets by the MCDM method thus showed that there are only four suitable GCMs, HadGEM2-AO, HadGEM2-ES, CSIRO.Mk3.6, and MIROC5 for data projections studying scenarios involving future water resources in Iraq.
A Comparative Study of Performance of Al-Khairat Gas Turbine Power Plant for Different Types of Fuel
Authors: Kadhim Hayder Jawad , Kadhim Thualfaqir J. , Alhwayzee Mohammed H 
Published: January 2020

Abstract
In this work, the effect of various types of fuels on the performance and efficiency of Al-Khairat gas turbine power plant in Kerbala City, Iraq has been investigated. The plant contains 10 General Electric Frame 9E gas turbine units, each of around 125 MW. Three fuels were used in this study; crude oil, natural gas, and biomass gasification producer (synthesis) gas. Currently, liquid crude oil is used as fuel for this plant. For comparison purposes, this power plant was simulated utilizing Aspen-Hysys software. Hysys simulation modelled in accordance with experimental power plant conditions and data was applied and showed high validity. Due to this validity, the plant’s efficiency and performance were calculated. Similarly, plant efficiency and performance for the other two fuels were also calculated. Furthermore, many important parameters that affect plant efficiency and performance for these three fuels (ambient temperature, pressure ratio, CO2 emission gases, heat rate and fuel consumption) were also investigated. Compared to the other two fuels, results show that the use of natural gas is the optimal choice for the plant, due to its increase of station efficiency and productivity, by approximately 3.12% and 10% respectively. At the same time, it reduced fuel consumption by 6% and produced less emission greenhouse gas.
Experimental and Numerical Investigation of Temperature Distribution in the Cutting Zone with Different Coated Tools in Orthogonal Turning Operations
Authors: Sahib Basim S. , Nassrullah Karrar S. 
Published: January 2020

Abstract
In orthogonal turning operations, the mechanical energy is converted into heat. The generated heat influences tool life and wear, and the accuracy and quality of workpieces. In the current work, the temperature distribution at cutting zone was studied experimentally and numerically. The K-type thermocouple was utilized to measure the cutting zone temperature during turning process for steel AISI 1010. DEFORM-2D has been utilized to simulate the turning operation, which was carried out using many coated and uncoated carbide tools. The experimental tests were implemented at constant depth of cut with different feed rates and cutting speeds. The results of numerical and experimental tests are illustrated. The influences of coated and uncoated tools, feed rate and cutting speed in temperature distribution at cutting zone are discussed, whereby the TiN/Al2O3/TiCN coated tool has the lowest temperature distribution at cutting zone compared to the other coated and uncoated tools, while the uncoated tool has the highest temperature distribution compared to coated cutting tools. Also, the increasing of cutting speed and feed rate led to an increase of temperature at the cutting zone.
Advance Acceptance Status Model for E-learning Based on University Academics and Students
Authors: Mousa Ayad Hameed , Mousa Seham Hameed , Mousa Sundus Hameed , Obaid Hazim Allawi 
Published: January 2020

Abstract
E-learning provides students with the possibility of accessing, repeating, and using learning materials wherever and whenever they want. The philosophy of e-learning is not to replace the conventional learning process; it instead provides a new method and approach that offers opportunities for much faster delivery of knowledge. Teachers and students are the most significant actors in the process of educational transformation, and technology acceptance is measured by positive reactions from users based on their utilisation of technology to support those assignments designed for such purposes. In higher education institutions in Iraq, the use of e-learning has become compulsory and there is thus a critical need to study student and teacher behaviours in response to this. Accordingly, this paper undertakes an investigation based on the Technology Acceptance Model (TAM) to examine academics’ and students’ acceptance of and adoption of e-learning in university education in their roles as universities’ main actors. This paper focuses on teachers and students with no background in ICT, investigating their acceptance of e-learning as a learning method. A seven-point Likert scale questionnaire was systematically developed, validated, and used as a data collection instrument with 450 students and 75 university lecturers from two separate colleges. A clustering sampling method was used in the sampling selection process, and several hypotheses were proposed and tested via the paired T-test. The paper’s outcomes can be classified into three categories: it helps to determine to what extent e-learning is accepted by non-expert users; it provides evidence of new factors that influence application of e-learning, extending the TAM model; and, finally, it provides meaningful recommendations for higher education institutions to utilise before adopting e-learning to maximise acceptance. In particular, the results indicate that academics’ and students’ intention to use e-learning is positively influenced by both perceived usefulness and perceived ease to use.
DC-AC Inverter with Tap Changing Transformer
Authors: Mohsin Mustafa H , Al-Shamaa Nabil K 
Published: January 2020

AbstractIn this paper a new single phase seven and eleven level inverter based on a tap changer transformer is developed to generates seven and eleven non-equal voltage levels from two DC sources. The model of inverter thus presented does not suffer from voltage balancing issues. The DC sources are connected to the primary side of the tap changer transformer with the help of a microcontroller circuit (Arduino UNO), with several semiconductor switches offering sequential modality. At the secondary side of transformer, the output voltage is generative, and Proteus/Software manipulation is performed. This technique reduces the Total Harmonic Distortion (THD) of the output voltage significantly.
Control strategy to improve power transmission capacity from wind farms to weak AC grids
Authors: Nawir M H , Marei M M , Altuma A S 
Published: January 2020

Abstract
—With the increasing connection of large wind farms based on direct driven Permanent Magnet Synchronous Generators (PMSGs) to weak AC grids, the steady state characteristics of such wind farms, particularly those connected to very weak AC systems with a Short Circuit Ratio (SCR) of 1, are important factors for analysis with a view to improvement. In this paper, the issue is thus analysed in order to identify the factors limiting transfer capability from wind farm output. This paper thus presents a simulation model of a wind farm connected to a very weak AC grid, and a vector control strategy is used with respect to the full power converters of the wind farm in order to track current order injected from the converters into the AC system. A supplementary outer loop control is proposed to support grid voltage and to maximise transferred power into the very weak AC grid, based on a droop gain which is allowed to update the reactive power reference for reactive power control for the grid side converter based on changes to the output of the wind turbine, within grid code requirements. The simulation results prove that the proposed control system offers a promising method for addressing challenges arising in active power transmission, and thus increasing transferred active power from such wind farms to very weak grids.
Performance Evaluation of Flux-Switching Permanent Magnet with Modifications to Stator and Rotor
Authors: Barzegari Bafghi Mohammad Hussein , Vahedi Abolfazl , Mohammad-Alikhani Arta 
Published: January 2020

Abstract
A flux-switching motor is a synchronous electric motor in which both field and armature coils are placed on the stator. There are thus three different stator structure types with regard to field excitation: permanent magnet, direct current field excitation, and hybrid. The rotor structure of the motor in this study reflected two types: integrated and multi-piece structure. The permanent magnet flux switching motor with integrated rotor structure offers more advantages and more attention has been paid to this as compared to other electric motors in various industries. The major advantages of this type are high torque density, ease of manufacture, high reliability, and robustness of rotor. However, these flux switching motors have relatively high cogging torque, and while work has been done on reducing the cogging torque and some literature published, most such works have focused on modifying the rotor tooth, skewing the rotor. These works study the effect of rotor shaping on motor performance, while in this paper, new rotor shapes are also considered. Finally, a method is introduced to minimise the cogging torque that has least adverse effect on other effective parameters such as torque density. Using the results of other papers, the finite element method is used to find the best method of rotor shaping in this paper.
Design and Modeling of a Soft Artificial Heart by Using the SolidWorks and ANSYS
Authors: Ali Saad Mahmood , Ali Zahraa Jasim , Abd Mays Mahde 
Published: January 2020

Abstract
Investigating the biomechanical behaviour of a soft artificial heart is a hard task as such things are very complicated in terms of both material properties and geometry. This work focused on developing, designing, modelling and analysing a new generation, low cost, easily operable, full-size, low power consumption, and durable soft artificial heart intended to replace an original heart on a parmanent basis. Numerical simulation and investigation of the artificial heart were implemented using SolidWorks 17 and ANSYS 15.7, with a Multiphysics static structural model, fluent fluid flow (CFX), and fluent fluid poly-flow (CFD) analysis systems used in order to determine the dynamic response and effects of pressurised blood on heart performance during blood flow cycles. The biomechanical modeling and analysis of the soft artificial heart were implemented using the finite element modelling in ANSYS R18.0. To improve and verify the biomechanical performance, Design Expert 11.0 software and a response surface methodology (RSM) technique were used. The simulation results showed that as maximum levels of absolute pressure were applied on the ventricles and air pressurised chambers, the performance of the heart remained secure. The results also showed that strain energy, total deformation, maximum principal elastic strain, stress and fatigue safety factors, and fatigue life all reached thier optimum values when using the SIBSTAR 103T with polyetherimide/silicone (PSN4) Nano-composite elastomers.
Energy dissipation in gabion weirs
Authors: Al-Fawzy A M , Al-Mohammed F M , Alwan H 
Published: January 2020

AbstractThe present study investigates the effect of hydraulic jumps as criteria for representation of the energy dissipation of flow in gabion weirs. A set of 25 laboratory experiments and 188 operation tests were carried out using a laboratory flume with dimensions 10 m long by 0.3 m wide, and 0.5 m high. The tested gabion weir had different five possible lengths, 0.4 m, 0.6 m, 0.8 m, 1.0 m, and 1.2 m, and the filling material used was natural quarry mono-graded gravel in five different sample sizes of average equivalent diameter 11.75 mm, 16.50 mm, 22.00 mm, 31.25 mm, and 43.75 mm. Operation discharge values ranged between 0.7 to 15.0 l/s. The data set was subject to dimensional analysis to generate dimensionless groups, and correlated using the Buckingham Pi-Theorem. The results of this analysis showed that the distance of hydraulic jump has a direct relationship with discharge and an inverse relationship with the diameter of the gravel in the sample. For specified discharges, the distance of hydraulic jump had an inverse relationship with the length of the gabion weir and a direct relationship with the proposed energy dissipation parameter.