基于Petri网的考试系统智能出卷的研究

一般的网络考试系统是从题库中随机选题组卷,容易造成考卷难度不一影响考试的公平性.提出了使用petri网模型,采用启发式随机替换算法来控制考试系统出题难度的解决方案.     

基于在线神经网络的自适应控制器的设计与应用

针对线性控制系统自适应性较弱的缺点,在其基础上设计了一种基于在线神经网络的自适应控制器．该控制器根据被控对象和参考模型之间的误差调整网络权值,在线抵消被控对象的未建模动态特性和不确定因素．文中以某小卫星姿态控制系统为例,对所提出的自适应控制器进行设计和仿真．结果表明,神经网络以很高的精度跟踪和在线补偿不确定项,改善了线性控制系统的动态性能．     

实验室智能排课的研究

针对目前实验室排课的具体情况,提出实现实验室排课的智能化的理论方法.通过分析实验室排课的资源集和约束条件,推导出实验室排课需求集(RCRL),从而提出了一种实验室智能排课的求解算法-AICRL.     

海藻糖对银杏叶过氧化物酶活性的影响

对银杏叶过氧化物酶热稳定性、最适pH值及海藻糖对酶热稳定性的保护作用和pH值的影响进行了初步研究.结果表明,用40℃和50℃分别处理30 min,过氧化物酶活性分别剩余78%和39%,在60,70,80℃下活性可分别维持27,18和3 min.银杏叶过氧化物酶最适pH值为6.4和9.2.加入海藻糖后酶活性略有降低(活性丧失约8%),但加热后海藻糖的保护优势得以显现,海藻糖浓度为0.14 mol/L时保护效果最好,而且不同温度处理下酶活的下降趋势均较对照组缓慢,尤其在50,60,70℃条件下,相比对照组高出12%~27%的活性,加热时间长短对海藻糖的保护效果无太大影响.经0.14 mol/L浓度的海藻糖处理后,酶活的最适pH值为6.6和9.4.     

激光标刻的复杂区域填充算法

为减少填充线段和提高激光加工效率,对复杂区域的填充算法进行了研究．采用延长某些岛屿边界将包含岛屿的区域变为单连通域;然后用最长边延长法和最长边平行截取法将单连通域分解为简单凸多边形,简单凸多边形填充方法是先找到凸多边形所有边对应的高最小的那条边,平行该边进行填充,最后对填充线段的连接顺序进行优化处理．与传统的固定方向扫描填充相比,采用本算法可使复杂区域和实心文字的激光标刻效率提高20％～40％．     

分年龄段的互惠模型的行波解

讨论了一类分年龄段的生物种群互惠模型的行波解存在性问题．在一般带时滞的互惠Lotka—Volterra模型基础上,考虑了年龄段和空间非局部等因素对反应扩散方程行波解存在性的影响．构造了一对合适的上下解,利用单调迭代方法证明了模型的两个平衡点之间行波解的存在性,进一步丰富了单调方法的内容．     

Incorporating textual and management factors into financial distress prediction: A comparative study of machine learning methods

Financial distress prediction (FDP) has been widely considered as a promising approach to reducing financial losses. While financial information comprises the traditional factors involved in FDP, nonfinancial factors have also been examined in recent studies. In light of this, the purpose of this study is to explore the integrated factors and multiple models that can improve the predictive performance of FDP models. This study proposes an FDP framework to reveal the financial distress features of listed Chinese companies, incorporating financial, management, and textual factors, and evaluating the prediction performance of multiple models in different time spans. To develop this framework, this study employs the wrapper-based feature selection method to extract valuable features, and then constructs multiple single classifiers, ensemble classifiers, and deep learning models in order to predict financial distress. The experiment results indicate that management and textual factors can supplement traditional financial factors in FDP, especially textual ones. This study also discovers that integrated factors collected 4 years prior to the predicted benchmark year enable a more accurate prediction, and the ensemble classifiers and deep learning models developed can achieve satisfactory FDP performance. This study makes a novel contribution as it expands the predictive factors of financial distress and provides new findings that can have important implications for providing early warning signals of financial risk.     

Fabrication of solenoid-type microinductor with different magnetic core schemes by MEMS technique

0 IntroductionThere has been a great demand on micro DC/DCconverter for the applications of the portable electronicproducts such as mobile communication product CDMA(Code Division Multiple Access) ,portable notebookcom-puter ,microprocessor ,digital camcorder andso on.Mag-netic components such as inductors and transformers arethe essential components in constructingthe power supplytransformer ,filter , oscillator , amplifier and micro DC/DCconverter ,andthe miniaturization of inductor an…     

条形不耦合平面布药技术在硐室爆破中的应用

为了研究条形药包硐室爆破在复杂环境下的应用问题,首先分析了条形药包的作用机理,根据已有硐室爆破平面药包布设的半理论丰经验公式,建立了条形药包平面布设数学模型。并通过工程实例将条形药包布设理论运用于平面布药实践,缩短了平面布设条形药包的设计周期。研究表明,在山体爆破中采用条形不耦合平面布药技术能显著提高有效松动率,降低大块率,减少二次爆破量。同时也减小了爆破振动对周边环境的破坏影响。     

羊栖菜多糖分离纯化和结构的初步鉴定

将提取的羊栖菜多糖用sevage法除蛋白、H2O2脱色后得到羊栖菜多糖半纯品,依次通过DE-AE-52、Sephadex G-200柱层析分离纯化后得到SFPS-B2、SFPS-C1、SFPS-D2三个多糖组分,用Sephacryl S200-HR柱层析鉴定纯度,三种组分的多糖为均一多糖,质量分数分别为86.02%、81.05%、86.95%.对SFPS-D2进行结构初步研究,通过紫外光谱、红外光谱和毛细管电泳分析,结果表明SFPS-D2不含蛋白质和核酸,多糖组成以β构型的吡喃糖苷键为主,含有硫酸基-O-SO3,其单糖组成以木糖、葡萄糖和半乳糖为主,其比例为木糖∶葡萄糖∶半乳糖=3.45∶5.8∶1.