全IP电视直播节目的即时回看技术

介绍了已运用于实践中的一种全IP电视直播节目即时回看技术,用户通过遥控器一键实现直播节目的即时回看,极大地提升了用户的观看体验。通过在临汾市智慧广电全IP融合业务网建设实践项目中的使用,技术的先进性和有效性得到实践验证。     

电力保护装置自动测试系统设计与研究

电力保护装置在出厂前要进行严格的板卡测试,传统板卡测试系统自动化程度较低,功能不够强大,且开发成本高,通用性不好。针对以上不足,设计了一种基于虚拟仪器的板卡测试系统,该系统主要由测试程序和上位机两部分组成,测试程序主要完成对板卡设备的模块化测试,并给出测试结果;上位机通过以太网与测试板卡通信,借助FTP和telnet技术,完成整个测试程序的发送、执行、测试结果的获取等功能。以电力保护装置内的CPU板卡为研究对象,结果表明,该测试系统可对板卡进行高效率自动测试,测试结果可靠,故障信息可追踪,可有效提高电力保护装置调试的通过率,保证企业产品的可靠性。     

Field-Effect Chiral Anomaly Devices with Dirac Semimetal

Charge-based field-effect transistors (FETs) greatly suffer from unavoidable carrier scattering and heat dissipation. Analogous to valley degree of freedom in semiconductors, chiral anomaly current in Weyl/Dirac semimetals is theoretically predicted to be nearly nondissipative over long distances, but still lacks experimental ways to efficiently control its transport. Here, field-effect chirality devices are demonstrated with Dirac semimetal PtSe₂, in which its Fermi level is close to the Dirac point in the conduction band owing to intrinsic defects. The chiral anomaly is further corroborated by the planar Hall effect and nonlocal valley transport measurement, which can also be effectively modulated by external fields, showing robust nonlocal valley transport with micrometer diffusion length. Similar to charge-based FETs, the chiral conductivity in PtSe₂ devices can be modulated by electrostatic gating with an ON/OFF ratio of more than 10³. Basic logic functions in the devices are also demonstrated with electric and magnetic fields as input signals.     

烟草除尘过程中节能减排优化研究

使用全面试验法,对除尘风机的空转时间进行研究,分析了风机空转的原因,并通过增加"制丝需求启动信号"逻辑控制建立了切丝工序与除尘风机的联动程序。本研究对企业产生了一定的经济效益,并可为同领域其他方面的节能减排提供参考和方法。     

A fuzzy logic PI control with feedforward compensation for hydrogen pressure in vehicular fuel cell system

In a vehicular fuel cell system, alternative load and frequent purge action can lead to anode pressure varies with the hydrogen mass flow fluctuation. It's crucial to control the pressure difference between anode and cathode within a reasonable range to avoid adverse phenomena such as membrane failure, reactant starvation, or even water management fault. In this paper, an improved proportional integrative (PI) controller by the fuzzy logic technique that considers the engineer experience and knowledge on the hydrogen supply system behavior is proposed for hydrogen pressure control, in which the PI parameters are tuned by a fuzzy decision process. Furthermore, load current and purge action regarded as input disturbances are applied for feedforward compensation to reduce the pressure response hysteresis. A hydrogen supply subsystem based on the proportional valve is modeled, and corresponding parameters are determined by analyzing the response time and steady pressure fluctuation. The performance of the conventional PI controller, the fuzzy logic PI (FLPI) controller and fuzzy logic PI with feedforward (FLPIF) controller is validated. The presented results indicated that the FLPI controller significantly improves the dynamic response of hydrogen pressure compared to the PI controller, and the FLPIF controller can further reduce overshoot caused by disturbance. Finally, the proposed FLPIF controller is implemented on a rapid prototype platform of the hydrogen supply subsystem and an actual fuel cell system, exhibiting satisfactory performance.     

基于深度EPG的智能导航平台建设

随着三网融合的大力推进以及双向互动业务的大力开展,运营商使用原有简单的EPG不足以支撑开展更多的增值业务,不能主动为用户推荐节目,不能为运营商带来新的收入机会。作为重要的创新能力支撑系统,介绍了江苏有线智能导航平台的设计与应用,为相关广电运营商提供一定的设计参考。     

面向二进制程序的导向性模糊测试方法

为了解决当前模糊测试技术中变异存在一定的盲目性以及变异生成的样本大多经过相同的高频路径的问题，提出并实现了一种基于轻量级程序分析技术的二进制程序模糊测试方法。首先对目标二进制程序进行静态分析来筛选在模糊测试过程中阻碍样本文件深入程序内部的比较指令；随后对目标文件进行插桩来获取比较指令中操作数的具体值，并根据该具体值为比较指令建立实时的比较进度信息，通过比较进度衡量样本的重要程度；然后基于模糊测试过程中实时的路径覆盖信息为经过稀有路径的样本增加其被挑选进行变异的概率；最后根据比较进度信息并结合启发式策略有针对性地对样本文件进行变异，通过变异引导提高模糊测试中生成能够绕过程序规约检查的有效样本的效率。实验结果表明，所提方法发现crash及发现新路径的能力均优于模糊测试工具AFL-Dyninst。     

Fuzzy logic approach in resource classification

Conventional geostatistical prediction methods can be used to carry out resource classification in ore beds and for reliability measurements. A field investigation based on lignite thickness data was conducted for resource classification in Eskisehir-Mihaliccik-Koyunagili coal basin. Moreover, a fuzzy logic-based resource classification method has been recently proposed to eliminate the uncertainties encountered in the conduct of conventional resource classification procedure. Fuzzy logic-based classification provides gradual transitions between two adjacent resource classes. In addition, the proposed method can classify each block by assigning a membership degree for handling decision-making problems encountered in conventional resource classification methods.     

Optimal interval type-2 fuzzy fractional order super twisting algorithm: A second order sliding mode controller for fully-actuated and under-actuated nonlinear systems

In this paper, a novel interval type-2 fuzzy fractional order super twisting algorithm (IT2FFOSTA) which is essentially a second order sliding mode controller is presented. The proposed IT2FFOSTA enhances fractional order super twisting algorithm (FOSTA) by taking advantage of an interval type-2 fuzzy fractional order sliding surface (IT2FFOSS) for some classes of fully-actuated and under-actuated nonlinear systems in presence of uncertainty. The FOSTA significantly reduces the amount of chattering and the IT2FFOSS results in decreasing the tracking error, control effort, and chattering level. In order to control under-actuated systems, a hierarchical sliding surface is employed. The multi-tracker optimization algorithm is utilized to adjust the controller’s parameters; this leads to an optimal performance for the IT2FFOSTA. To examine the performance of the IT2FFOSTA, some simulation and experimental tests on three examples of different classes of fully-actuated and under-actuated systems, including ball and plate, inverted pendulum, and ball and beam systems are carried out. The simulation and experimental results demonstrate the superiority of the IT2FFOSTA in reducing the amount of chattering, tracking error, and control effort compared to those of the other control methods.