一次性塑料快餐盒盖成型工艺分析及逆向设计     

吕淑艳 《包头职业技术学院学报》2020,(1):1-2,15

采用逆向思维方法,详细分析了一次性快餐盒盖的成型工艺,并对其结构进行改进设计。为那些以实物为制造基础的产品的设计提供了借鉴,在缩短产品开发周期,提高经济效益方面,起着重要作用。  相似文献   

高职院校农业类专业课程教学改革的实践与反思     

哈满林  李萍  黄守敏 《安徽职业技术学院学报》2020,(1):88-91

文章针对高职农业类专业学生类型结构趋向多元化、教学内容与生产实际相脱离、教学团队的结构亟待优化、教学组织形式亟待改进等突出问题,通过对岗位职业能力、工作任务进行梳理,重构教学内容,改进教学方法,组建结构化教学团队,会同行业专家共同开发活页式教材,使教学过程可控、课堂活力提升,显著改善了教学效果。  相似文献   

Optimal synchronization controller design for complex dynamical networks with unknown system dynamics     

Ya-Wei Cao  Guang-Hong Yang  Xiao-Jian Li 《Journal of The Franklin Institute》2019,356(12):6071-6086

In this paper, the optimal synchronization controller design problem for complex dynamical networks with unknown system internal dynamics is studied. A necessary and sufficient condition on the existence of the optimal control minimizing a quadratic performance index is given. The optimal control law consists of a feedback control and a compensated feedforward control, and the feedback control gain can be obtained by solving the well-known Algebraic Riccati Equation (ARE). Especially, in the presence of unknown system dynamics, a novel adaptive iterative algorithm using the information of system states and inputs is proposed to solve the ARE to get the optimal feedback control gain. Finally, a simulation example shows the effectiveness of the theoretical results.  相似文献   

Intermittent control strategy for synchronization of fractional-order neural networks via piecewise Lyapunov function method     

Ying Yang  Yong He  Min Wu 《Journal of The Franklin Institute》2019,356(8):4648-4676

In this paper, the synchronization problem of fractional-order neural networks (FNNs) with chaotic dynamics is investigated via the intermittent control strategy. Two types of intermittent control methods, the aperiodic one and the periodic one, are applied to achieve the synchronization of the considered systems. Based on the dynamic characteristics of the intermittent control systems, the piecewise Lyapunov function method is employed to derive the synchronization criteria with less conservatism. The results under the aperiodically intermittent control show more generality than the ones via the periodically intermittent control. For each of the aperiodic and periodic cases, a simple controller design process is presented to show how to design the corresponding intermittent controller. Finally, two numerical examples are provided to demonstrate the effectiveness of the obtained theoretical results.  相似文献   

Linear output-feedback-based semi-global stabilization for switched nonlinear time-delay systems     

Zhenhua Li  Lijun Long  Jun Zhao 《Journal of The Franklin Institute》2019,356(13):7224-7245

This paper focuses on the problem of semi-global output-feedback stabilization for a class of switched nonlinear time-delay systems in strict-feedback form. A switched state observer is first constructed, then switched linear output-feedback controllers for individual subsystems are designed. By skillfully constructing multiple Lyapunov–Krasovskii functionals and successfully solving several troublesome obstacles, such as time-varying delay and switching signals and nonlinearity in the design procedure, the switched linear output-feedback controllers designed can render the resulting closed-loop switched system semi-globally stabilizable under a class of switching signals with average dwell time. Furthermore, under some milder conditions on nonlinearities, the semi-global output-feedback stabilization problem for switched nonlinear time-delay systems is also studied. Simulation studies on two examples, which include a continuous stirred tank reactor, are carried out to demonstrate the effectiveness of the proposed approach.  相似文献   

Multi-lagged-input iterative dynamic linearization based data-driven adaptive iterative learning control     

Na Lin  Ronghu Chi  Biao Huang  Zhongsheng Hou 《Journal of The Franklin Institute》2019,356(1):457-473

This article presents a multi-lagged-input based data-driven adaptive iterative learning control (M-DDAILC) method for nonlinear multiple-input-multiple-output (MIMO) systems by virtue of multi-lagged-input iterative dynamic linearization (IDL). The original nonlinear and non-affine MIMO system is equivalently transformed into a linear input-output incremental counterpart without loss of dynamics. The proposed learning law utilizes the desired trajectory to cancel the influence from iteration-by-iteration variations, as well as additional multi-lagged inputs to improve control performance. The developed iterative estimation law is more effective and also makes estimation of the unknown parameters easier because the dynamics for each parameter to represent are decreased by dividing the system into multiple components in the multi-lagged-input IDL formulation. Moreover, the proposed M-DDAILC does not need an explicit and accurate model. It is proved to be iteratively convergent with rigorous analysis. Both a numerical example and a practical application to a permanent magnet linear motor are provided to verify the validity and applicability of the proposed method.  相似文献   

Dynamics of a stochastic multigroup SIQR epidemic model with standard incidence rates     

Qun Liu  Daqing Jiang  Tasawar Hayat  Ahmed Alsaedi 《Journal of The Franklin Institute》2019,356(5):2960-2993

In this paper, we consider a stochastic multigroup SIQR epidemic model with standard incidence rates. By using the stochastic Lyapunov function method, we establish sufficient conditions for the existence of a stationary distribution of the positive solutions to the model. Then we establish sufficient conditions for extinction of the diseases. A stationary distribution means that all the individuals can be coexistent and persistent in the long term. Finally, some examples and numerical simulations are introduced to illustrate our theoretical results.  相似文献   

法庭科学领域科研伦理建设          下载免费PDF全文

彭斯璐  赵兴春  权养科 《科研管理》2019,40(9):277-281

法庭科学作为特殊的应用性科学，其研究和应用中时有涉及伦理问题，但目前中国尚缺乏法庭科学中科研伦理和行为规范问题的研究，相关伦理审查机构和审查规章仍是空白。从当前法庭科学科研伦理实践出发，针对职业伦理规范建设不足、科研伦理监管缺位以及法庭科学职业特色与伦理要求的冲突进行分析，为法庭科学研究科研伦理管理提出可参考的建议。  相似文献   

The role of a digital engineering platform in appropriating the creation of new work-related mind-set and organisational discourse in a large multi-national company     

《International Journal of Information Management》2019

This paper reports on a case study involving a strategic and innovative approach to creation of an in-house multifaceted digital engineering platform (the DEP) in overcoming a number of organisational problems at a multinational engineering company. The DEP was to be used strategically for simplifying the operational complexity and to create and appropriate new work-related mind-set and new organisational discourse to achieve homogenous working across the organisation, which is a huge challenge. The need for this system emerged from the need to resolve many organisational services related problems that carried phenomenal amount of processes, health and safety risks and to regulate, and, control the running of engineering project. Research data were collected using a longitudinal case study approach over a period of six months. In order to make sense of how the DEP helped the organisation, the study used certain elements of Extended Structuration Theory as a lens to assess the case study. This research discovered that the DEP succeeded in creating and appropriating work-related mind-set and organisational discourse. It also had real influence on working processes and employees at all levels while encouraging transparency, responsiveness, agility and accountability. It continues to help the organisation to govern, manage and maintain good standard of service but many barriers still remain.  相似文献   

Idea generation in biomedical engineering courses using Design Heuristics     

Jin Woo Lee  Anastasia Ostrowski  Aileen Huang-Saad  Colleen M. Seifert 《European Journal of Engineering Education》2019,44(3):360-378

ABSTRACT

With increasing demand for improved medical equipment and healthcare, next-generation biomedical engineers need strong design skills. Equipping biomedical engineering students with tools for idea generation and development can increase student design success. Design Heuristics are an ideation tool developed through empirical studies of product designs. While identified in the mechanical engineering space, Design Heuristics may be applicable in biomedical engineering design. In our study, we implemented a Design Heuristics session during upper-level undergraduate and first-year graduate biomedical engineering design courses. We examined the applicability of Design Heuristics within individual and team concept generation contexts. The findings demonstrated that biomedical engineering students were able to use Design Heuristics to generate multiple concepts, and that initial concepts produced using Design Heuristics were carried over into final team design. The results support the applicability of Design Heuristics to student idea generation in biomedical engineering design.  相似文献