Construction and Innovation of Comprehensive Evaluation Means of PBL+OBE-based Software Engineering Practical Courses

Software engineering is an engineering discipline that guides software developers to carry out software development,software maintenance,and software management.The traditional evaluation methods of software engineering courses do not highlight the training goal of outcomebased education(OBE).This paper systematically studies the evaluation methods for practical courses in software engineering from three aspects:course evaluation guidelines,course evaluation methods and course evaluation effects;establishes a comprehensive,scientific,and objective system of course evaluation;effectively measures students’learning effect;promotes teachers to continuously improve the teaching process;and thus improves the teaching quality of software engineering courses.Besides the general approach,this paper also takes software project construction practice as an example to demonstrate the effect of the proposed approach.

Design and Implementation of Multi-collaborative Training System

With the rapid development of computer technology,network and information technology have been widely used in people’s daily lives,which has brought great convenience to labor and life.At the same time,people are increasingly dependent on computer technology.In this case,the social demand for computer professionals is increasing.However,due to the rapid changes and continuous updates of computer technology,the training of talents in computer specialty in China is far from meeting the demand and quality requirements of the society for this kind of talents.Colleges and universities are the important departments that cultivate computer professionals and technicians for the society.When cultivating talents in computer specialty,colleges and universities must conform to the requirements of the development of the times,adjust teaching strategies in a timely manner according to the actual needs of the society,build a talent training system,build a practical training teaching system of computer specialty,innovate teaching modes and teaching contents,and improve students’professional skills through perfect practical teaching,so as to ensure that they can skillfully apply computer technology to solve practical problems in the learning process and further improve their employment competitiveness.Therefore,this paper analyzes the practical teaching system of computer specialty,puts forward corresponding solutions to the existing problems,constructs a multi-collaborative practical training system,and implements the system.The implementation results show that the system can better meet the needs of students at different levels,and the results are fairer.Students’recognition and sense of acquisition of courses have also been greatly improved.The accumulated experience and data also provide good support for our continuous improvement of the system in the future.

Construction and Implementation of OBE-based Practical Course for Software System Development with Solid Foundation and Continuous Improvement

Software engineering is a highly practical major,and students need a lot of hands-on practice to transform the theoretical contents learned in class into the practical ability to solve practical problems,so practical courses are an essential and important part in the process of training talents in software engineering.From the point of view of cultivating talents in software engineering,this paper expounds the important position of practical courses in software engineering in the process of cultivating talents,analyzes the problems in the existing practical courses,and puts forward the construction ideas and characteristics of practical courses in software engineering which strengthen the foundation,advance steadily,and face the output.Taking the practical course for software system development as an example,this paper introduces in detail the concrete implementation process,achievements,existing problems and countermeasures of the course.

Quantifying Contribution of DER-Integrated EV Parking Lots to Reliability of Power Distribution Systems

In the future smart cities,parking lots(PLs)can accommodate hundreds of electric vehicles(EVs)at the same time.This trend creates an opportunity for PLs to serve as a potential flexibility resource,considering growing penetration of EVs and integration of distributed energy resources DER(such as photovoltaic and energy storages).Given this background,this paper proposes a comprehensive evaluation framework to investigate the potential role of DER-integrated PLs(DPL)with the capability of vehicle-to-grid(V2G)in improving the reliability of the distribution network.For this aim,first,an overview for the distribution system with DPLs is provided.Then,a generic model for the available generation capacity(AGC)of DPLs with consideration of EV scheduling strategy is developed.On the above basis,an iterative-based algorithm leveraging sequential Monte Carlo simulation is presented to quantify the contribution of DPLs to the reliability of the system.In order to verify the effectiveness of the proposed method,a series of numerical studies are carried out.The simulation results show that the integration of DPLs with the V2G capability could help to improve the reliability performance of distribution grid to a great extent and reduce the adverse impact incurred by EV accommodation,if utilized properly.

Design and Implementation of a Comprehensive Training Program for Software Engineering Talents’ Practical Ability

In the process of cultivating software engineering professionals,the practical teaching of professional courses is an indispensable link.In order to enable students to understand,consolidate and master theoretical knowledge,improve the ability to solve problems by combining theory with practice,and achieve the goal of combining theoretical knowledge with practice.Adopting the planning of through-type training,complete the teaching work of three practical courses of software system design,software system construction,and software product construction.Through the implementation of the plan,the digitization of teaching resources,the virtualization of real enterprises,the intelligentization of teaching guidance,the visualization of teaching process,and the panorama of learning process are realized.By adopting the teaching methods of taskdriven online practice teaching,artificial intelligence-based teaching training support and teaching process,and result big data evaluation,the students’comprehensive practical ability can be improved finally,and the whole practice teaching reform can provide experience for the follow-up reform.

Mechanochemical route to fabricate an efficient nitrate reduction electrocatalyst

The electrochemical nitrate reduction reaction(NO_(3)RR)to ammonia under ambient conditions is a promising approach for addressing elevated nitrate levels in water bodies,but the progress of this reaction is impeded by the complex series of chemical reactions involving electron and proton transfer and competing hydrogen evolution reaction.Therefore,it becomes imperative to develop an electro-catalyst that exhibits exceptional efficiency and remarkable selectivity for ammonia synthesis while maintaining long-term stability.Herein the magnetic biochar(Fe-C)has been synthesized by a two-step mechanochemical route after a pyrolysis treatment(450,700,and 1000℃),which not only significantly decreases the particle size,but also exposes more oxygen-rich functional groups on the surface,promoting the adsorption of nitrate and water and accelerating electron transfer to convert it into ammonia.Results showed that the catalyst(Fe-C-700)has an impressive NH_(3)production rate of 3.5 mol·h^(−1)·gcat^(−1),high Faradaic efficiency of 88%,and current density of 0.37 A·cm^(−2)at 0.8 V vs.reversible hydrogen electrode(RHE).In-situ Fourier transform infrared spectroscopy(FTIR)is used to investigate the reaction intermediate and to monitor the reaction.The oxygen functionalities on the catalyst surface activate nitrate ions to form various intermediates(NO_(2),NO,NH_(2)OH,and NH_(2))and reduce the rate determining step energy barrier(*NO_(3)→*NO_(2)).This study presents a novel approach for the use of magnetic biochar as an electro-catalyst in NO_(3)RR and opens the road for solving environmental and energy challenges.

Kekulé调制声子晶体中的赝表面狄拉克涡旋拓扑态

近年来,拓扑学的概念被引入到声学系统,声学超材料以及声子晶体中的拓扑效应被广泛研究.其中,声学拓扑边界传输模式具有低损耗、背向散射抑制的特性和良好的鲁棒性,在声信号探测、噪声控制等方面拥有较大的应用潜力.近期,高度局域在狄拉克涡旋处的零维拓扑束缚态在多种物理系统中被发现,成为相关领域的研究热点.但是现有研究中的声学结构大多受限于二维空间,自由空间中亚波长尺度的狄拉克涡旋拓扑态亟待探索.本文基于声赝表面波实现了自由空间中的类马约拉纳束缚态,即通过在硬质基板上排布蜂窝晶格阵列的空气圆柱孔,并在系统中施加一个与格点位置相关的Kekulé调制,产生了局域在结构表面和涡旋中心的声学拓扑束缚态;证明了这种拓扑束缚态的频率固定在狄拉克频率处,且不受Kekulé调制幅度的影响.此外,进一步分别引入粒子空穴对称性保护和破缺的缺陷,验证了这种特殊的拓扑束缚态在粒子空穴对称性保护时对缺陷具有较好的鲁棒性.本研究在基于声能局域和捕获的新型声学功能器件的设计方面具有潜在的应用前景.

基于合成维度空间中深亚波长拓扑角态的声彩虹捕获

近年来,拓扑声学相关研究发展迅猛,其理论最初源于凝聚态物理中所发现的拓扑特性.其中,声学高阶拓扑绝缘体支持能量高度局域在拐角处的低维拓扑角态,且本征频率简并.然而,如何打破拓扑角态的多重简并,实现可调控的频率分布并设计新型声学多功能拓扑器件,是亟待解决的关键问题.在该研究中,通过对二维声子晶体中的单元施加平移形变,与真实空间自由度相结合构建四维合成空间.研究发现,随着平移形变自由度的调制,Zak相位连续变化,而合成空间的非零拓扑不变量确保了系统的非平庸拓扑特性,拓扑角态的频率简并被打破.基于此结论,进一步设计了基于合成维度的声学高阶拓扑绝缘体阵列,以实现局域在深亚波长拐角上的双通道声彩虹捕获.实验结果表明,不同通道上声彩虹拓扑角态的本征频率增加方向相反,在空间选择性能量捕获等领域具有潜在的应用前景.

Carbon armour with embedded carbon dots for building better supercapacitor electrodes

The microstructure design of electrode material is a crucial point to optimize the supercapacitor’s electrochemical properties.In this work,a Bi-based nanocomposite with a three-layer structure(Bi–Bi_(2)O_(3)@carbon armour(CA)/carbon dots(CDs))is synthesized and investigated.This material inherits high capacitance and high activity from bismuth-based materials,the coated CA protects the structure from complete oxidization and improves surface hydrophilicity.Furthermore,CDs in CA can enhance the ion conduction efficiency between the catalyst,carbon membrane,electrolyte.As a consequence,the specific capacitance of the electrode reaches 973 F·g^(−1)under 1 A·g^(−1),the energy density achieves 32.5 Wh·kg^(−1)with a power density of 266.9 W·kg^(−1),with impressive electrochemical stability that Coulomb efficiency of the electrode remains about 100%after 5000 cycles.Furthermore,in-situ Fourier transformation infrared(FT-IR)analyzes the structure evolvement of the material during synthesis and finds that the annealing process of the material removes a great number of oxygen-containing groups of CA and CDs,generating oxygen vacancies,defects,thus active sites,which enhance the capacitance of the material.

Wind-integration benefits of controlled plug-in electric vehicle charging

Flexibility in plug-in electric vehicle(PEV) charging can reduce the ancillary cost effects of wind variability and uncertainty on electric power systems. In this paper, we study these benefits of PEV charging, demonstrating that controlled PEV charging can reduce costs associated with wind uncertainty and variability. Interestingly, we show that the system does not require complete control of PEV-charging loads to mitigate the negative cost impacts of wind variability and uncertainty. Rather, PEV owners giving the system a two-hour window of flexibility in which to recharge their vehicles provides much of the benefits that giving full charging control does.

A vector autoregression weather model for electricity supply and demand modeling

Weather forecasting is crucial to both the demand and supply sides of electricity systems. Temperature has a great effect on the demand side. Moreover, solar and wind are very promising renewable energy sources and are, thus, important on the supply side. In this paper, a large vector autoregression(VAR) model is built to forecast three important weather variables for 61 cities around the United States. The three variables at all locations are modeled as response variables. Lag terms are used to capture the relationship between observations in adjacent periods and daily and annual seasonality are modeled to consider the correlation between the same periods in adjacent days and years. We estimate the VAR model with16 years of hourly historical data and use two additional years of data for out-of-sample validation. Forecasts of up to six-hours-ahead are generated with good forecasting performance based on mean absolute error, root mean square error, relative root mean square error, and skill scores. Our VAR model gives forecasts with skill scoresthat are more than double the skill scores of other forecasting models in the literature. Our model also provides forecasts that outperform persistence forecasts by between6% and 80% in terms of mean absolute error. Our results show that the proposed time series approach is appropriate for very short-term forecasting of hourly solar radiation,temperature, and wind speed.

Fe-doped SnO_(2) nanosheet for ambient electrocatalytic nitrogen reduction reaction

Ammonia plays a vital role in the development of modern agriculture and industry.Compared to the conventional Haber–Bosch ammonia synthesis in industry,electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising and environmental friendly strategy to synthesize ammonia.Here,inspired by biological nitrogenase,we designed iron doped tin oxide(Fe-doped SnO_(2))for nitrogen reduction.In this work,iron can optimize the interface electron transfer and improve the poor conductivity of the pure SnO_(2),meanwhile,the synergistic effect between iron and Sn ions improves the catalyst activity.In the electrocatalytic NRR test,Fe-doped SnO_(2) exhibits a NH_(3) yield of 28.45μg·h^(−1)·mgcat^(−1),which is 2.1 times that of pure SnO_(2),and Faradaic efficiency of 6.54%at−0.8 V vs.RHE in 0.1 M Na_(2)SO_(4).It also shows good stability during a 12-h long-term stability test.Density functional theory calculations show that doped Fe atoms in SnO_(2) enhance catalysis performance of some Sn sites by strengthening N–Sn interaction and lowering the energy barrier of the rate-limiting step of NRR.The transient photovoltage test reveals that electrons in the low-frequency region are the key to determining the electron transfer ability of Fe-doped SnO_(2).

BiVO_(4)/TiO_(2) heterojunction with rich oxygen vacancies for enhanced electrocatalytic nitrogen reduction reaction

The large-scale production of ammonia mainly depends on the Haber-Bosch process,which will lead to the problems of high energy consumption and carbon dioxide emission.Electrochemical nitrogen fixation is considered to be an environmental friendly and sustainable process,but its efficiency largely depends on the activity and stability of the catalyst.Therefore,it is imperative to develop high-efficient electrocatalysts in the field of nitrogen reduction reaction(NRR).In this paper,we developed a BiVO_(4)/TiO_(2) nanotube(BiVO_(4)/TNT)heterojunction composite with rich oxygen vacancies as an electrocatalytic NRR catalyst.The heterojunction interface and oxygen vacancy of BiVO_(4)/TNT can be the active site of N2 dynamic activation and proton transition.The synergistic effect of TiO_(2) and BiVO_(4) shortens the proton transport path and reduces the over potential of chemical reaction.BiVO_(4)/TNT has high ammonia yield of 8.54µg·h^(−1)·cm^(−2) and high Faraday efficiency of 7.70%in−0.8 V vs.RHE in 0.1 M Na_(2)SO_(4) solution.

A core-satellite structured type Ⅱ heterojunction photocatalyst with enhanced CO_(2) reduction under visible light

Photocatalytic reduction of carbon dioxide into valuable chemicals is a sustainable and promising technology that alleviates the greenhouse effect and energy crisis.In this study,the Mn_(3)O_(4)/FeNbO_(4) type Ⅱ heterojunction photocatalyst with a core-satellite structure was synthesized by the facile soft chemical method.The formation of a nano-heterojunction is supposed to effectively improve light capture,charge transfer,and interfacial charge separation in the photochemical reaction.Meanwhile,the heterojunction has a good ability to capture and activate CO_(2).Our results show that the prepared Mn_(3)O_(4)/FeNbO_(4) photocatalyst exhibit obvious enhanced catalytic properties in the photocatalytic CO_(2) reduction reaction,where the CH_(4) yielding rate is 1.96 and 9.81 times those of FeNbO_(4) and Mn_(3)O_(4),respectively.The transient photovoltage test(TPV)shows that the low frequency electrons are crucial to the effective transfer of photogenerated electrons and holes in the Mn_(3)O_(4)/FeNbO_(4) nano heterojunctions.Analysis of in situ Fourier transform infrared spectroscopy(FTIR)verifies the effective CO_(2) adsorption on the Mn_(3)O_(4)/FeNbO_(4) surface and the high selectivity of CH_(4) products.These properties of the Mn_(3)O_(4)/FeNbO_(4) photocatalyst infer its broad prospects in the fields of carbon fixation and energy conservation.

BCAT1 promotes lung adenocarcinoma progression through enhanced mitochondrial function and NF-κB pathway activation

Lung cancer is one of the most prevalent and malignant cancers,among which lung adenocarcinoma(LUAD)accounts for the majority and remains a major cause of cancer-related mortality worldwide(Cui et al.,2019).Despite the growing intensity of research on the pathobiology and progression of lung cancer and the fact that many genes have been identified as potential drivers and targets for therapy(Luo et al.,2019;Zhang et al.,2019),the treatment and prognosis of lung cancer patients have hardly improved.Therefore,this study aimed to investigate the precise mechanism of lung cancer development and explore efficient diagnostic and therapeutic methods for clinical treatment.