Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. Ho...Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. However, the problem of complexity of selecting vectors and capacitor voltage unbalance needs to be solved when the algorithm of direct torque control （DTC） is implemented on DCMLI. In this paper, a fuzzy DTC system of an induction machine fed by a three-level neutral-point-clamped （NPC） inverter is proposed. After introducing fuzzy logic, optimal selecting switching state is realized by applying various strategies which can distinguish the grade of the errors of stator flux linkage, torque, the neutral-point potential, and the position of stator flux linkage. Consequently, the neutral-point potential unbalance, the dr/dr of output voltage and the switching loss are restrained effectively, and desirable dynamic and steady-state performances of induction machines can be obtained for the DTC scheme. A design method of the fuzzy controller is introduced in detail, and the relevant simulation and experimental results have verified the feasibility of the proposed control algorithm.展开更多
结合制造商关于产品的质量决策研究电商平台关于销售契约和物流模式的最优组合策略.根据平台运营实际结合不同的销售契约和物流模式提出4种组合策略:代理销售-物流外包(direct selling and outsourcing,DO),代理销售-自建物流(direct se...结合制造商关于产品的质量决策研究电商平台关于销售契约和物流模式的最优组合策略.根据平台运营实际结合不同的销售契约和物流模式提出4种组合策略:代理销售-物流外包(direct selling and outsourcing,DO),代理销售-自建物流(direct selling and self-logistics,DS),批发转售-物流外包(reselling and outsourcing,RO)和批发转售-自建物流(reselling and self-logistics,RS).通过构建不同策略下的顺序博弈模型,求解制造商和平台关于产品质量､销售价格和物流服务水平的最优决策,探讨物流模式和销售契约对制造商产品质量决策的影响.对比均衡结果发现:相比于物流服务外包,由平台的自建物流系统提供配送服务不仅可以激励制造商提升产品质量和降低销售价格,还有助于提高双方收益;平台的最优组合策略与收取的佣金比率密切相关,当佣金比率低于某一阈值时,其最优策略为DS策略;反之,最优策略为RS策略;此外,该阈值与产品的质量成本系数呈正相关.展开更多
信任涉及一个社会的基本秩序,是进行合作、交易的基础,也是激发购买行为发生的关键变量。长期以来,由于大众媒体对非法传销事件的大量负面报道,使消费者对合法直销和非法传销发生了认知上的混淆,从而导致了直销模式不可信的刻板印象的...信任涉及一个社会的基本秩序,是进行合作、交易的基础,也是激发购买行为发生的关键变量。长期以来,由于大众媒体对非法传销事件的大量负面报道,使消费者对合法直销和非法传销发生了认知上的混淆,从而导致了直销模式不可信的刻板印象的产生。本研究以直销品牌玫琳凯、雅芳和非直销品牌欧莱雅、资生堂为样本,通过心理学的内隐联想测验(IAT,Implicit Association Test)在性别和积极情景线索两个维度的检验中,证实了中国消费者对包括国际著名品牌在内的整个直销行业不信任的刻板印象以及积极情景线索可以起到降低刻板印象的作用。展开更多
文摘Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. However, the problem of complexity of selecting vectors and capacitor voltage unbalance needs to be solved when the algorithm of direct torque control （DTC） is implemented on DCMLI. In this paper, a fuzzy DTC system of an induction machine fed by a three-level neutral-point-clamped （NPC） inverter is proposed. After introducing fuzzy logic, optimal selecting switching state is realized by applying various strategies which can distinguish the grade of the errors of stator flux linkage, torque, the neutral-point potential, and the position of stator flux linkage. Consequently, the neutral-point potential unbalance, the dr/dr of output voltage and the switching loss are restrained effectively, and desirable dynamic and steady-state performances of induction machines can be obtained for the DTC scheme. A design method of the fuzzy controller is introduced in detail, and the relevant simulation and experimental results have verified the feasibility of the proposed control algorithm.
文摘结合制造商关于产品的质量决策研究电商平台关于销售契约和物流模式的最优组合策略.根据平台运营实际结合不同的销售契约和物流模式提出4种组合策略:代理销售-物流外包(direct selling and outsourcing,DO),代理销售-自建物流(direct selling and self-logistics,DS),批发转售-物流外包(reselling and outsourcing,RO)和批发转售-自建物流(reselling and self-logistics,RS).通过构建不同策略下的顺序博弈模型,求解制造商和平台关于产品质量､销售价格和物流服务水平的最优决策,探讨物流模式和销售契约对制造商产品质量决策的影响.对比均衡结果发现:相比于物流服务外包,由平台的自建物流系统提供配送服务不仅可以激励制造商提升产品质量和降低销售价格,还有助于提高双方收益;平台的最优组合策略与收取的佣金比率密切相关,当佣金比率低于某一阈值时,其最优策略为DS策略;反之,最优策略为RS策略;此外,该阈值与产品的质量成本系数呈正相关.
文摘信任涉及一个社会的基本秩序,是进行合作、交易的基础,也是激发购买行为发生的关键变量。长期以来,由于大众媒体对非法传销事件的大量负面报道,使消费者对合法直销和非法传销发生了认知上的混淆,从而导致了直销模式不可信的刻板印象的产生。本研究以直销品牌玫琳凯、雅芳和非直销品牌欧莱雅、资生堂为样本,通过心理学的内隐联想测验(IAT,Implicit Association Test)在性别和积极情景线索两个维度的检验中,证实了中国消费者对包括国际著名品牌在内的整个直销行业不信任的刻板印象以及积极情景线索可以起到降低刻板印象的作用。
