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51.
传统粒子滤波(PF)直接采用状态转移先验分布作为重要性密度函数来近似后验概率密度函数,使得后验概率密度函数未包含量测信息。针对此问题,提出了一种改进高阶容积粒子滤波(CPF)的系统状态估计算法。算法采用七阶正交容积卡尔曼滤波(7th-CQKF)对PF的粒子进行传递,使得先验分布更新阶段融入最新量测信息;通过7th-CQKF设计重要性密度函数,提高对状态后验概率密度的逼近程度;通过反比例函数计算粒子权重,突出大噪声粒子与小噪声粒子权重差别,提高粒子有效性。仿真结果表明,改进高阶容积粒子滤波的估计精度高于容积粒子滤波(CPF)。 相似文献
52.
Luby变换(Luby Transform,LT)码作为信道编码应用于电力线通信(Power Line Communication,PLC),可实现电信号的可靠传输。度分布对LT码编译码性能的影响至关重要。为了得到更优的度分布,首先调整二进制指数分布(Binary Exponential Distribution,BED)中的度数比例,获得一种译码性能更优的改进的二进制指数分布(Improved BED,IBED)。然后,根据IBED在冗余度较小时译码成功率高,而冗余度增大后鲁棒孤子分布(Robust Soliton Distribution,RSD)的译码性能表现更佳的特点,通过求和归一化的方式将IBED与RSD两种度分布的优势进行有机结合,提出一种新型二进制鲁棒孤子分布(Binary RSD,BRSD)。仿真结果表明,与其他方法及传统的RSD相比,采用新度分布进行LT编码,可明显降低译码开销,并节约编译码耗时。将新型度分布应用于基于LT码的PLC系统中,能有效地抑制PLC信道中各种噪声对电信号的干扰,并提高通信效率。 相似文献
53.
Huong T.X. Nguyen 《Asia Pacific Business Review》2019,25(1):100-122
This paper investigates the impacts of different network ties on export propensity of Vietnamese small and medium enterprises (SMEs) in the manufacturing sector. Using data from a survey of over 2,600 manufacturing SMEs in 2015, we found that social networks contribute positively to the export propensity of SMEs, while the size of business networks negatively associates with the likelihood of export. However, bank networks and political networks are not significant for the propensity to export of Vietnamese SMEs. We discuss the results in detail and offer recommendations for SME owners, managers and policy makers. 相似文献
54.
Jackeline Rios-Torres Jun Liu Asad Khattak 《International Journal of Sustainable Transportation》2019,13(2):123-137
Improving fuel economy and lowering emissions are key societal goals. Standard driving cycles, pre-designed by the US Environmental Protection Agency (EPA), have long been used to estimate vehicle fuel economy in laboratory-controlled conditions. They have also been used to test and tune different energy management strategies for hybrid electric vehicles (HEVs). This paper aims to estimate fuel consumption for a conventional vehicle and a HEV using personalized driving cycles extracted from real-world data to study the effects of different driving styles and vehicle types on fuel consumption when compared to the estimates based on standard driving cycles. To do this, we extracted driving cycles for conventional vehicles and HEVs from a large-scale U.S. survey that contains real-world GPS-based driving records. Next, the driving cycles were assigned to one of three categories: volatile, normal, or calm. Then, the driving cycles were used along with a driver-vehicle simulation that captures driver decisions (vehicle speed during a trip), powertrain, and vehicle dynamics to estimate fuel consumption for conventional vehicles and HEVs with power-split powertrain. To further optimize fuel consumption for HEVs, the Equivalent Consumption Minimization Strategy (ECMS) is applied. The results show that depending on the driving style and the driving scenario, conventional vehicle fuel consumption can vary widely compared with standard EPA driving cycles. Specifically, conventional vehicle fuel consumption was 13% lower in calm urban driving, but almost 34% higher for volatile highway driving compared with standard EPA driving cycles. Interestingly, when a driving cycle is predicted based on the application of case-based reasoning and used to tune the power distribution in a hybrid electric vehicle, its fuel consumption can be reduced by up to 12% in urban driving. Implications and limitations of the findings are discussed. 相似文献
55.
We explore the relationship between inequality and entrepreneurial activity. Drawing on cross-sectional data from a largescale survey of the economic conditions of individuals across India, we develop a number of dimensions of inequality to explore empirically how inequality interacts with entrepreneurship, operationalized as self-employment or as employing other people. We find compelling evidence that there are thresholds to becoming self-employed, and even more so to assembling the combinations of resources and personal attributes required to become an employer. Greater inequality leaves more people unable to make the transition to self-employment, leaving casual laboring as the occupation of necessity. At the same time, inequality increases the number of employers in a society, by concentrating resources - particularly land and finance - enough for significant numbers of people to be able to cross this higher threshold. Lastly, greater differentiation into social or religious groups curtails the ability to cross either entrepreneurial threshold, presumably by limiting the extent and benefits of social networks of value for entrepreneurship. 相似文献
56.
Christopher Ambrey Matthew Bitzios 《International Journal of Sustainable Transportation》2018,12(10):737-752
This study investigates the correlates of a resident's walking behaviors and aims to shed light on mechanisms through which walking may be encouraged. The results of this investigation paint a complex and nuanced picture of the residents’ walking behaviors in South East Queensland, Australia. The results suggest that sociodemographic characteristics separately may contribute greatly to whether or not one engages in walking behaviors. Further, cumulatively these differences might be greater for some groups of residents compared to others. One of the most prominent findings of the study is that the purpose, the characteristics of the origin, and the characteristics of the destination of a trip tended to be similar in the heterogeneity they exhibit over the distribution of time spent walking. For example, pick something up, undertake work, or engage in personal business, move to or from a workplace, shop, or social place are activities that tend to be associated with walking as a main mode of transport and a higher number of walking episodes. However, these trips tended to be short. 相似文献
57.
针对机载三维音频应用的实时性需求,提出了一种基于单耳相对头相关传递函数和改进型混响模型的机载三维音频快速实现方法,在较传统实现方式性能无明显下降的情况下降低了80%的计算量。对提出的算法在F-16战斗机模拟强噪声环境下进行相关主观试听实验,同时在某型飞机音频系统中实验验证。实验结果表明,所提方法在实时处理3路三维音频时,三维音频方位分辨精度在5°以内,可满足实际机载平台使用需求。 相似文献
58.
Even when the neoliberal ideology of the free market was more dominant than it now is, the state was involved in economic activities that could be undertaken by private firms. State capitalism takes increasingly diverse forms, including beyond direct, partial or even indirect ownership. This paper briefly reviews some of these forms without claiming to be exhaustive as the shape state capitalism takes differs widely across the institutionalized contexts of countries. We assess state capitalism using Polanyi’s double movement framework and argue that this framework needs adaptation to novel forms of state capitalism that include, e.g., state-owned multinationals and sovereign wealth funds. 相似文献
59.
Linnea Haag Uni Sallnäs Erik Sandberg 《International Review of Retail, Distribution & Consumer Research》2019,29(3):321-339
ABSTRACTMarket-oriented aspects of retail internationalisation have received a lot of research attention since the 1990s. However, beyond these aspects lies also supply-chain oriented capabilities that are necessary for retailers to successfully internationalise into foreign sales markets. By using a perspective based on resource-based theories, this paper explores supply-chain oriented capabilities that facilitate retail internationalisation. The research is based on a multiple case study of three Swedish retailers. Through the perspective of research based theories, specifically capabilities, the empirical data is studied in a single-case as well as a cross-case analysis. Findings reveal three supply chain-oriented capability categories (leadership capability, integration capability and learning capability) of importance for retail internationalisation. Resources necessary for the capabilities are to be found internally at the retailer, but also externally at other firms. This research adds to the market-oriented knowledge on retail internationalisation by adding a supply-chain oriented perspective. Further, it provides an understanding of the early phases of retail internationalisation. 相似文献
60.
Montakan Chubchuwong 《Asia Pacific Journal of Tourism Research》2019,24(2):168-179
The objectives of this research are firstly, to study the characteristics of CSR activities conducted for international business groups. Secondly, to analyze the factors that impact business travelers’ satisfaction with CSR activities, and thirdly, to analyze the influence of satisfaction with CSR activities on destination attachment and destination loyalty. A questionnaire survey was conducted with 127 business participants from three corporate meetings and one convention group. The results reveal the characteristics of CSR activities of corporate meetings and conventions in Thailand. Business travelers’ satisfaction with CSR activities is influenced by their personal altruistic attitudes and the efficacy of local service providers. Satisfaction with CSR activities has a direct impact on destination attachment and an indirect impact on destination loyalty. CSR activities could be used as tools to influence the revisit intention of corporate meeting and convention participants. A CSR activity during a business trip is a novel concept that can be utilized by destination management companies as well as national tourism organizations to develop satisfying tourism products. 相似文献