浅论超缓凝混凝土

由于城市建设的不断进行,城市的建筑物和构筑物朝着多元化和综合化的方向发展,这就要求作为建筑的主要材料-混凝土必须与其相适应。本文主要探讨了一种特殊的混凝土-超缓凝混凝土,总结了目前国内外相关的规范资料,以西安某单位的混凝土配比强度试验,分析得出西安地区引进超缓凝混凝土的应用前景。     

边际效用递减规律的再发现

本文的成果主要体现在两个方面:第一,将时间维度导入效用函数,实现了对边际效用递减规律认识的一次真正的飞跃;第二,将需求在需求要素的层次上进行分解,使边际效用递减规律有了更为准确和牢靠的基础。在这两个成果的基础上,对效用的可测量性、商品的同质性假说等问题进生了前瞻性的探讨。     

基于实物期权的房地产最优开发时机

本文主要利用实物期权定价理论,结合房地产实际投资状况,通过处理房地产开发项目的单位价格和单位建设成本之间的相互影响,建立了关于价格与成本之间的房地产最优投资决策时机模型,探讨了房地产开发的最适时机的选择问题。     

信道估计偏差对空时编码的OFDM系统性能的影响

本文研究了采用空时编码的OFDM系统的性能，通过Monte Carlo仿真分析了系统性能和信道估计偏差对系统的影响。     

AWGN信道下TH-PPM UWB通信系统性能分析与仿真

首先介绍了TH—PPM UWB信号，然后从理论上对加性高斯白噪声（AWGN）信道下系统的性能进行了分析，包括误码率分析和系统容量分析，最后对系统的误码率和接入用户数进行了仿真比较。结果表明，重复码长度、脉冲重复时间和用户数目的选取对系统的误码率都有较大的影响，同时，系统容量与输出信噪比和数据传输速率有关并趋于定值。     

When nature calls: The role of customer toilets in retail stores

The scarce previous literature indicates that the customer toilet facilities influence shopping value and should be a concern for retailers. However, customer toilets are often inadequately capitalised in retail stores. This study aims to provide a scientifically robust argument about the critical role of customer toilets in retail stores. The explanatory survey data (n=655) from a Finnish out-of-town department store is examined to explore (1) the importance that consumers place on the customer toilets and (2) the effect of toilet usage on actual shopping behaviour. The results support the assumptions of previous literature by suggesting that customer toilets are considered as an important store attribute and, more importantly, the use of toilets is associated with prolonged in-store time which, in turn, increases spending. The findings offer both academic and managerial contribution and encourage academics and practitioners to regard customer toilets as more than mere an unwanted property expense and discover their full marketing potential.     

微弱信号多站时差协同检测技术

针对现有时差相关检测方法难以有效检测微弱信号的现状,为提升现有检测系统对微弱信号的检测性能,提出了一种针对微弱信号的多站时差协同检测技术。通过在空间域内将多组时差站的相关结果积累,然后搜索二维网格中的最大值得到检验统计量。分析了检验统计量的概率分布,明确检验统计量在纯噪声条件下服从极值I型分布,依据奈威-皮尔逊（Neyman-Pearson）准则得到了检测门限。蒙特卡洛仿真结果表明,相同条件下,该方法比传统的相关检测的处理增益高约10lgK dB（K为时差线数目）     

HIGH‐ORDER SHORT‐TIME EXPANSIONS FOR ATM OPTION PRICES OF EXPONENTIAL LÉVY MODELS

The short‐time asymptotic behavior of option prices for a variety of models with jumps has received much attention in recent years. In this work, a novel second‐order approximation for at‐the‐money (ATM) option prices is derived for a large class of exponential Lévy models with or without Brownian component. The results hereafter shed new light on the connection between both the volatility of the continuous component and the jump parameters and the behavior of ATM option prices near expiration. In the presence of a Brownian component, the second‐order term, in time‐t, is of the form , with d₂ only depending on Y, the degree of jump activity, on σ, the volatility of the continuous component, and on an additional parameter controlling the intensity of the “small” jumps (regardless of their signs). This extends the well‐known result that the leading first‐order term is . In contrast, under a pure‐jump model, the dependence on Y and on the separate intensities of negative and positive small jumps are already reflected in the leading term, which is of the form . The second‐order term is shown to be of the form and, therefore, its order of decay turns out to be independent of Y. The asymptotic behavior of the corresponding Black–Scholes implied volatilities is also addressed. Our method of proof is based on an integral representation of the option price involving the tail probability of the log‐return process under the share measure and a suitable change of probability measure under which the pure‐jump component of the log‐return process becomes a Y‐stable process. Our approach is sufficiently general to cover a wide class of Lévy processes, which satisfy the latter property and whose Lévy density can be closely approximated by a stable density near the origin. Our numerical results show that the first‐order term typically exhibits rather poor performance and that the second‐order term can significantly improve the approximation's accuracy, particularly in the absence of a Brownian component.     

一种基于纠缠交换的远程量子链路建立策略

提出一种以纠缠交换作为核心技术的远程量子链路建立策略,建立了基于链路状态矩阵的量子链路模型并分析了纠缠交换的实现和矩阵表示。提出了链路协议栈以及端到端的建立策略,分析了矩阵控制下的纠缠交换和纠缠纯化流程,计算得出了在基于自动重传请求(ARQ)协议经典信息辅助下的链路时延和吞吐量与节点数、误帧率、平均距离、操作成功率之间的定量关系。仿真结果表明：处于同一状态区间内的链路性能随节点数呈现出较为一致和平缓的变化;不同区间内的链路性能差异较为显著,在节点平均距离为1 km、经典信息误帧率为0、纠缠保真度为0.98的情况下,当节点数分别为32、33和34时,链路时延分别为1.0770 ms、1.0903 ms和1.6690 ms,链路吞吐量分别为0.9285 kb/s、0.9172 kb/s和0.5992 kb/s。     

基于GPS驯服铷钟的频率校准系统设计

定期对GNSS接收机的外部频率源进行校准是保证定位精度的重要措施。介绍了GPS驯服铷 钟频率校准系统的工作原理和硬件组成,通过频率校准实验验证了该系统达到 了较好的长期频率准确度和短期频率准确度指标要求,保证了被校准频率源的精确度。