排序方式： 共有4条查询结果，搜索用时 140 毫秒
1
1.
提出了基于量化的可持续产品设计和评估方法.该方法使用产品设计的多标准来满足可持续产品从定性到定量的设计要求.建立的可持续发展产品定量方法集成了质量功能展开的概念与生命周期评估方法.它同时考虑客户需求和可持续发展的要求,并通过公理设计映射和基准测试方法将这些需求变为设计细节.将提出的方法应用在轮椅设计中.其设计基准选用了4种常用的轮椅并将其根据客户需求和可持续要求评级.设计矩阵用来确定轮椅功能要求和设计参数的关系.与最好的基准产品相比,所设计的轮椅可以降低成本13.8%,环境足迹18.55%,质量4.5%,以及组件数量2.2%. 相似文献
2.
This paper presents a powerful application of genetic algorithm （GA） for the minimization of the total harmonic current distortion （THCD） in high-power induction motors fed by voltage source inverters, based on an approximate harmonic model. That is, having defined a desired fundamental output voltage, optimal pulse patterns （switching angles） are determined to produce the fundamental output voltage while minimizing the THCD. The complete results for the two cases of three and five switching instants in the first quarter period of pulse width modulation （PWM） waveform are presented. Presence of harmonics in the stator excitation leads to a pulsing-torque component. Considering the fact that if the pulsing-torques are at low frequencies, they can cause troublesome speed fluctuations, shaft fatigue, and unsatisfactory performance in the feedback control system, the 5th, 7th, 1 lth, and 13th current harmonics （in the case of five switching angles） are constrained at some pre-specified values, to mitigate the detrimental effects of low-frequency harmonics. At the same time, the THCD is optimized while the required fundamental output voltage is maintained. 相似文献
3.
Christoph Randler Arash Rahafar Talat Arbabi Rebekka Bretschneider 《Mind, Brain, and Education》2014,8(4):214-219
One of the most intriguing results concerning chronopsychological effects at school is the worse school performance in evening‐oriented adolescents. The study intends to correlate affective state with chronotype. Therefore, we carried out a field study in adolescents in a natural setting (in school) and assessed their actual affective state during the very first lesson at school (8:00 a.m.). A total of 97 pupils (60 boys and 37 girls; mean age 13.14 ± SD 1.84; range 10–17 years) from class Grades 5, 6, 8, 9, and 10 participated in this study. We used the Composite Scale of Morningness (CSM) to assess morningness and the Adjective Checklist for Children (EWL40‐KJ) to assess mood. Morningness was positively associated with relaxation, good mood, and activation, and negatively related to bad mood, anger, and deactivation. No significant relationship was found related to excitation, aggression, anxiety, and depressiveness. Concerning the two general dimensions, CSM scores were positively related to positive mood and negatively to negative mood. 相似文献
4.
The use of an effective supervision mechanism is crucial between a student and supervisor. The essential knowledge shared and transferred between these two parties must be observed and understood very well in order to ensure that students are produced at good level of quality for future professional knowledge workers. The aim of this study was to conduct an assessment of the impact of individual, organisational and technical factors on knowledge sharing in a research supervision domain. In order to achieve this aim, a specific research model was developed. This model was based on systematically analysing and extracting all the knowledge-sharing impact factors and then choosing the more iterative and adaptable ones, according to research supervision models. These factors categorized to individual, organizational and technological factors. To effectively evaluate the research model, a quantitative research method was adopted. Data was collected by a survey of 150 students from the Faculty of Computing at Universiti Teknologi Malaysia. The Smart PLS tool was used for data analysis. In sum, the results of this research show that the individual factor in the research supervision domain – namely, the ability of students to share knowledge – in addition to technological factors – specifically, IT systems – have the greatest impact on knowledge sharing in the supervision process. In addition, it was shown that organisational factors including the culture of the university, social networks, and supervisor support have a positive impact on knowledge sharing in research supervision. However, when compared with individual and technical factors, the effect of organisational factors on knowledge sharing in research supervision was not particularly strong in the case of this study. A positive relationship did not exist between the learning strategy and knowledge sharing in research supervision. This study is among the first of its kind to empirically examine the antecedent factors of knowledge sharing in the context of research supervision. 相似文献
1