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81.
针对无线传感器网络分簇算法中能量分布不均衡导致的"热区"和簇头负载过重问题,提出了一种基于PSO算法优化簇头选举的非均匀分簇算法。在候选簇头选举和竞争半径计算过程中综合考虑节点动态能量、节点密度和节点距基站距离,将网络进行非均匀分簇,并引入PSO算法进行最终簇头选举。根据节点能量、节点密度和距基站距离确定簇间单跳多跳结合的路由规则,选取代价函数小的节点作为下一跳节点。基于节点信息熵确定融合阈值,进行簇内数据融合剔除冗余数据。仿真结果表明,改进算法的数据传输量比EEUC算法和UCRA算法分别提高了20%和10%,提升了数据的融合效率,有效延长了网络生命周期,簇头能量消耗得到均衡,减少了网络能量消耗,网络的整体性能显著优于其他对比算法。  相似文献   
82.
研究目的:分析家庭结构对农民流转土地意愿的影响,并揭示其内部机理的形成,以期为土地流转政策的完善提供参考。研究方法:因子分析法和结构方程模型。研究结果:(1)家庭人口特征、土地使用特征、户主个体特征及家庭决策特征4类外源潜变量会显著影响农地流转意愿;(2)可观测变量对外源潜变量的解释能力较强,其中,家庭总人口、实际经营及流转土地面积、户主年龄、家庭内部矛盾解决方式分别对这4类外源潜变量的解释能力相对较好,即家庭总人口越多、实际经营及流转土地面积越小、户主年龄越大、依赖于内部解决矛盾的家庭更愿意流转农地。研究结论:家庭结构主要通过主动依赖、扶养压力、收入偏好、农地保障、决策信息5种机理对流转意愿产生影响,未来土地流转政策的完善应重视解决这些问题。  相似文献   
83.
研究目的:基于全国典型村庄调研,分析不同地区农村宅基地闲置程度和成因,为农村宅基地集约利用和乡村振兴提供建议。研究方法:实地调研法、对比分析法。研究结果:(1)调研村庄宅基地闲置现象普遍,2018年闲置程度平均为10.7%。(2)各地村庄宅基地闲置程度差异明显。分区域看,东部村庄宅基地闲置程度最高,中部村庄最低;分城乡区位看,村庄离城市距离越远,宅基地闲置程度越高;分地形看,平原村庄宅基地闲置程度最高;分是否为贫困村庄看,村庄宅基地闲置程度随村庄贫困程度的加深而升高。(3)宅基地闲置是乡村人口结构变化与宅基地利用失衡的结果。长期外出务工、城镇有住房、“一户多宅”、宅基地损毁引起宅基地闲置的成因占比依次下降。(4)农村宅基地闲置受乡村地域内外宏微观因素综合影响,经济增长和城镇化引起的就业非农化、人口市民化是宅基地闲置的直接动因,现行城乡二元制度和宅基地管理制度是宅基地闲置的根本原因。研究结论:盘活利用农村闲置宅基地,需要因地制宜推动闲置宅基地整治利用、健全宅基地有偿使用和退出机制、创新城乡制度加快农业转移人口市民化。  相似文献   
84.
In an initial coin offering (ICO), new ventures raise capital by selling tokens to a crowd of investors. Often, this token is a cryptocurrency, a digital medium of value exchange based on the distributed ledger technology. Both the number of ICOs and the amount of capital raised have exploded since 2017. Despite attracting significant attention from ventures, investors, and policy makers, little is known about the dynamics of ICOs. This initial study therefore assesses the determinants of the amount raised in 423 ICOs. Drawing on signaling theory, the study explores the role of signaling ventures' technological capabilities in ICOs. The results show that technical white papers and high-quality source codes increase the amount raised, while patents are not associated with increased amounts of funding. Exploring further determinants of the amount raised, the results indicate that some of the underlying mechanisms in ICOs resemble those found in prior research into entrepreneurial finance, while others are unique to the ICO context. The study's implications are multifold and discussed in detail. Importantly, the results enable investors to more accurately understand crucial determinants of the amount raised (e.g., technical white papers, source code quality, token supply, Ethereum-standard). This reduces the considerable uncertainty that investors face when investing in ICOs and enables more informed decision-making.  相似文献   
85.
Using data for 18 major tourist originating countries to India from 2001 to 2015, this study examines the major determinants of international tourist arrivals in India. The results indicate that past experiences of the tourists, per capita income in the tourist originating country, relative costs of living between India and the country of origin, and the level of infrastructure development in India are key determinants of international tourist arrivals in India. Furthermore, both transportation and communication infrastructure are important in attracting tourists to India. In particular, evidence suggests that availability of road and air network and telephone connections has favourable impacts on international tourist arrivals in India. These results are robust to the inclusion of additional variables. These results have important policy implications.  相似文献   
86.
The “alternative”, “atypical” or “informal” workforce has grown in developed and developing countries alike. One of the more recent evolutions of informal employment has been of informal employment within formal enterprises. In the interest of flexibility and cost‐reduction, many formal firms increasingly resort to hiring workers on a temporary or informal basis. Alongside, and perhaps, as a result of the persistence and pervasiveness of informal employment, issues relating to inequality have come to the fore. This paper is motivated by these two intertwining aspects of Indian labor market—informality and wage inequality. Using nationally representative sample data, the paper examines trends in wage inequality among various forms of informal workers, overlaying these findings with broader trends in inequality. Using a regression based inequality decomposition, the paper compares the sources of wage inequality across different employment groups and the reasons for differences in wage inequality.  相似文献   
87.
高速移动环境下,无线信道具有时频双选性衰落的特性,使得滤波器组多载波(Filter Bank Multi-carrier,FBMC)系统产生长突发差错。将一种基于Baker映射的混沌交织算法应用在滤波器组多载波系统中,根据混沌密钥对发送数据进行分块和重新排列,按照Baker映射规则完成数据交织。此方法可以将长突发差错变为单突发差错,结合卷积编码能有效地纠正双选信道产生的长突发差错。仿真结果表明,在双选择信道中,基于混沌交织的滤波器组多载波系统误比特率性能优于传统基于块交织的滤波器组多载波系统。  相似文献   
88.
ABSTRACT

Equityholders of firms with high debt loads have an incentive to underinvest, a distortion that can be most costly for firms with attractive growth options. Using a novel patent-based measure of a firm's growth options, we find that firms issue more equity and shy away from debt financing when they have larger investment opportunities sets. The results are more pronounced among firms in patent-intensive industries. The findings suggest the existence of conflicts of interest between debtholders and equityholders. Our results are consistent with the use of conservative debt policies by technology-intensive firms to mitigate the debt overhang associated with their future growth options.  相似文献   
89.
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   
90.
This article aims to explore the sources of the observed transformation in the embeddedness of economic, business, and financial practices of Muslim individuals in comparison to premodern period Muslims. It argues that the predomination of instrumental reasoning in modern times, as opposed to substantive morality in everyday practice, is one of the main reasons behind the transformation of embeddedness of Muslim individuals. Instrumental reasoning, being the dominant methodology, leads to diminished submergence in social relations; that is not limited to interpersonal relationships, but further extended to the core religious acts. How such an emergent economic and business morality is reconciled with the Islamic substantive morality is examined. It is argued that “transformation of exception into norm” is the main method used to reconcile instrumental reasoning with Islamic law in fulfilling religious obligations, at least in terms of fulfilling the form and in complying with the necessities of modern life. This has led to the emergence of new economic and business moralities.  相似文献   
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