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1.
为了加快低密度奇偶校验(LDPC)码的译码速度,有效改善LDPC码的译码性能,针对校验节点更新过程中的对数似然比(LLR)值的大小,设计了一种LDPC码的动态加权译码方法。以IEEE 802.16e标准的奇偶校验矩阵为例,根据LLR值的变化规律,利用增长因子和抑制因子对和积译码算法和最小和译码算法进行动态加权。仿真结果显示,基于动态加权的译码方法相对于传统译码方法误码率都有明显改进,译码复杂度也有所降低。  相似文献   
2.
With advances in new technology, various formats of online advertising (e.g., in-stream video advertising) often force e-consumers to watch the advertisement during their goal-oriented activities, and this advertising interruption often makes them feel intruded upon and irritated. To reduce such negative reactions toward involuntary advertising exposures, this study examines whether offering e-consumers the option to choose advertising content can influence ad effectiveness in different degrees of forced exposure circumstance. Using a 2 (advertising content control: customization option vs. no option) × 2 (level of forced exposure: pre-rolls vs. rich media banners) factorial experiment, the researcher noted that advertising customization features generate a greater sense of relevance and increased advertising memory, which in turn may lead to more positive attitudes toward the ad regardless of the levels of forced exposure. The findings have theoretical and practical implications on the use of involuntary advertising interruptions in the web interface.  相似文献   
3.
In this paper, we consider the problem of optimal investment by an insurer. The wealth of the insurer is described by a Cramér–Lundberg process. The insurer invests in a market consisting of a bank account and m risky assets. The mean returns and volatilities of the risky assets depend linearly on economic factors that are formulated as the solutions of linear stochastic differential equations. Moreover, the insurer preferences are exponential. With this setting, a Hamilton–Jacobi–Bellman equation that is derived via a dynamic programming approach has an explicit solution found by solving the matrix Riccati equation. Hence, the optimal strategy can be constructed explicitly. Finally, we present some numerical results related to the value function and the ruin probability using the optimal strategy.  相似文献   
4.
Facebook has become an important platform for a brand–consumer relationship channel. The current study investigates the influence of perceived socialness and its effect on consumers’ attitude toward brands. Participants (N = 404) were recruited in a large southeast university. A 2 (socialness: high vs. low)?×?2 (feedback control: high vs. low)?×?2 (brand image: high vs. low) between-subject design was conducted. The results of this study identified three important findings. First, high (vs. low) socialness elicited higher perceived relationship commitment, brand trust, and more favorable brand attitude. Second, the effect of socialness on brand attitude was moderated by brand image (positive vs. negative). Third, the mediation analysis showed that the effect of socialness (high vs. low) on brand attitude was fully mediated by perceived relationship commitment and brand trust.  相似文献   
5.
The advance of cryptocurrencies has sparked wide concern over their interplay with the existing global financial market. This paper analyzes the risk spillover relation between cryptocurrencies and major financial assets, and unravels how cryptocurrencies could influence global financial systemic risk. We find that cryptocurrencies function as a separate risk source from traditional assets. Major legislative, financial and technological events in the cryptocurrency market may affect risk spillover dynamics. Although the overall penetration of cryptocurrencies is not yet deep, introducing cryptocurrency can significantly increase the systemic risk to traditional markets during low risk level episodes.  相似文献   
6.
Recent methodological developments provide a way to incorporate the temporal dimension when accounting for spatial effects in hedonic pricing. Weight matrices should decompose the spatial effects into two distinct components: bidirectional contemporaneous spatial connections; and unidirectional spatio-temporal effects from past transactions. Our iterative estimation approach explicitly analyses the role of time in price determination. The results show that both spatio-temporal components should be included in model specification; past transaction information stops contributing to price determination after eight months; and limited temporal friction is exhibited within this period. These findings highlight the decidedly non-linear temporal patterns of such information effects.  相似文献   
7.
宋敏  史婷  王茜 《水利经济》2018,36(6):20-25
明确港口腹地演变趋势、分析港腹耦合协调度,对长三角地区港腹联动发展具有重要意义。量化港口系统—腹地系统综合指标评价体系,运用高斯烟羽模型在2006、2011、2016年3个时间节点上测算长三角地区主要港口影响强度,并对腹地范围进行划分,利用耦合协调模型定量分析港口系统和直接腹地经济系统耦合协调度。研究结果表明:长三角地区港口呈现"一超多强"的格局,以上海港为中心,各港口多极发展;港口腹地范围整体稳定,局部波动,上海港的边缘腹地不断缩减;港口与腹地的耦合协调度处于上升态势,宁波—舟山港腹耦合协调度最高。  相似文献   
8.
为了解决宏蜂窝与飞蜂窝构成的两层异构网络上行干扰与资源分配问题,提出了一种在认知型飞蜂窝的双层异构网中结合子信道分配和功率控制进行资源分配的框架。通过对异构网中跨层干扰问题进行分析与建模,将求解最优子信道分配矩阵和用户发射功率矩阵作为干扰管理问题的解决方法。模型中认知型飞蜂窝网络子信道和飞蜂窝网络用户构成非合作博弈,双方利用效用函数最优值进行匹配,构成初始信道分配矩阵;再由接入控制器根据接入条件从初始信道分配矩阵中筛选用户,并优化接入用户的发射功率矩阵,得到最优子信道分配矩阵和功率矩阵。仿真结果表明,优化框架提高了双层异构网络中飞蜂窝网络用户的吞吐量和接入率,降低了异构网中跨层干扰。  相似文献   
9.
Post-Keynesian institutionalist economists like Wallace Peterson and John Kenneth Galbraith recognized that the impact of uncertainty on economic wellbeing depends in part on the degree of control people have over the sources and consequences of it. Given the inability of government and other large institutions to reduce uncertainty or to provide citizens with the ability to manage it, mediating structures are considered as an alternative means of promoting economic security. The article concludes by describing and evaluating several of these alternatives.  相似文献   
10.
极点作为谐振区雷达目标的最主要电磁特性,具有很大的空间目标识别前景。但是在使用频域观测数据提取目标极点时,存在虚假极点和估计精度问题。针对上述问题,首先通过加窗和截断改进了后时响应信号的获取流程,抑制了虚假极点影响;然后采用最小描述长度法(MDL)估计极点个数,避免了定阶错误引起的虚假极点;最后采用联合矩阵束法估计极点,有效减少了单角度数据估计极点时存在的遗漏极点和虚假极点问题。FEKO软件验证表明,所提算法具有更高的精度和抗噪能力。  相似文献   
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