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1.
摘 要:为了提高码索引调制(code index modulation,CIM)系统的传输效率,提出了一种具有更低复杂度的单输入单输出(single input single output,SISO)的广义正交码索引调制(generalized orthogonal code index modulation,GQCIM)系统。CIM 系统使用扩频码和星座符号传输信息,但只能激活两个扩频码索引和一个调制符号。而 GQCIM 系统以一种新颖的方式克服了只激活一个调制符号的限制,同时充分利用了调制符号的正交性,增加扩频码索引以传输更多的额外信息位,提高了系统的传输效率。此外,分析了GQCIM系统的理论性能,推导了误码率性能的上界。通过蒙特卡罗仿真验证了GQCIM系统的性能,对比发现GQCIM系统的理论和仿真性能一致。而且在相同的传输效率下,结果显示GQCIM系统的性能优于同样具有正交性的调制系统,如广义码索引调制(generalized code index modulation,GCIM)系统、CIM系统、码索引调制-正交空间调制(code index modulation aided quadrature spatial modulation,CIM-QSM)系统、码索引调制-正交空间调制(code index modulation aided spatial modulation,CIM-SM)系统、脉冲索引调制(pulse index modulation,PIM)系统。 相似文献
2.
Analog integrated circuit design has as integral parts both analytical reasoning and numerical validation in the process from topology construction to sizing. Given a circuit topology, different circuit sizing results can be obtained from different processes of sizing inference. Sizing methods by simulation-based numerical searching have been a continuously studied subject. However, almost all approaches in this category require an overwhelming number of circuit simulations to arrive at an optimized sizing result. On the other hand, many published manual sizing methods by using the conventional device equations also require repeated SPICE simulations to correct the equation-based sizing results. This paper proposes a systematic gm/ID-based initial sizing method specifically customized for designing multiple-stage operational amplifiers (Op Amps). A main feature of the proposal is to use circuit-level design equations as constraints on the gm/ID table lookup method to substantially reduce the uncertainty in the sizing calculations. As a result, a significant amount of SPICE based correction work can be reduced to complete an initial sizing. The proposed sizing procedure includes a few regular sizing rules customized to the configuration of multi-stage Op Amps. We validate the proposed sizing method by application to several multi-stage Op Amp examples with a capacitive load or Miller compensation. Simulations have justified that the produced initial sizing results can achieve most of the prespecified design targets. 相似文献
3.
彭家寅 《计算机工程与应用》2020,56(12):93-97
目的是利用高维量子纠缠态为量子信道,讨论未知单粒子态的受控隐形传输问题。以三维量子纠缠态为信道,提出一个二维任意单粒子态的受控隐形传输协议。提出了以任意[d]-维量子纠缠态为量子信道,[t]-维任意单粒子态的隐形传输协议[(t相似文献
4.
E. Nahvifard 《Journal of Modern Optics》2020,67(6):475-480
ABSTRACTIn this paper, we study detection of the state non-classicality for a quantum harmonic oscillator by a qubit in the presence of dissipation effects. We show that dissipation can enhance the effectiveness of the method in case of using the corrected form of the related nonclassicality witness. Such an improvement is attributed to the fact that dissipation leads to probing a surface, instead of a curve, of the complex plane for non-classicality condition on normally-ordered characteristic function. 相似文献
5.
利用Gleeble-3500热模拟试验机研究了低活化马氏体钢在变形温度为850~950 ℃、应变速率为0.001~1 s-1条件下的热变形行为。建立了流变应力本构方程,并评估了该方程的预测能力。绘制了低活化马氏体钢在不同应变下的热加工图。结果表明:在较高的应变速率条件下,该材料主要发生动态回复,在较高变形温度和较低应变速率下具有明显的动态再结晶特征;本构方程的预测结果与实验结果符合良好;变形温度870~930 ℃、应变速率0.001~0.01 s-1和变形温度920~950 ℃、应变速率0.3~1 s-1分别是真应变为0.4和0.6下最优的热加工区域。 相似文献
6.
Consumers’ and policy makers’ interest in local foods is growing. Accordingly, researchers are also increasingly paying attention to the consumption of local foods. Studies have identified preference for local foods as an emergent consumer ideology called “locavorism”, but they have not yet addressed its antecedents or put it into a theoretical context. In addition, extant research provides several insights into local food buying behaviour in developed economies (e.g., USA, UK, Germany, or Italy); however, studies simultaneously conducted in developed and emerging economies are lacking. To address these research gaps, this study develops a conceptual framework with proposed relationships among values, beliefs (locavorism and fresh start mindset), and attitudes towards and intentions to purchase local foods in China and Denmark. We conducted an online survey in China and Denmark that evaluated our constructs with pre-developed multiple-item measures. Using structural equation modelling to test the integrated model, we find that values and long-term orientation are antecedents of consumer beliefs but the influences of values on consumer beliefs differ between collectivistic-dominated China and individualistic-dominated Denmark. Specifically, collectivistic values are significantly and positively related to locavorism in both countries, while individualistic values are strongly linked to locavorism only in Denmark; collectivistic values have no effects on fresh start mindset for the two samples, but individualistic values are significantly and positively related to a fresh start mindset in Denmark. In addition, consumer beliefs are significantly and positively associated with attitudes towards and intentions to buy local foods. Local food marketers can use our findings to target their communications more effectively. 相似文献
7.
交通信号灯识别包括检测和状态识别,在智能交通系统中发挥重要作用。基于YOLOv3算法提出了一种交通信号灯检测与状态识别模型。针对交通信号灯相较于交通场景中其他目标具有尺度小的特性进行了算法的设计:降低骨干网络的下采样倍率以增加小尺度目标的特征描述能力;通过增大特征图的尺度来改进多尺度特征融合;引入广义交并比作为检测任务的损失函数来改进目标边界框的回归效果。同时,根据交通信号灯本身的特性,使用颜色和形状约束的方法对信号灯进行状态识别和类别验证。最后在公开的Bosch交通信号灯数据集上和实际的城区道路进行了实验验证。实验结果表明,所提出的算法能够提升交通信号灯识别的精度和召回率,识别准确率可以达到90%左右。 相似文献
8.
Cristina Dai Prá Martens Franklin Jean Machado Mauro Luiz Martens Filipe Quevedo Pires de Oliveira e Silva Henrique Mello Rodrigues de Freitas 《International Journal of Project Management》2018,36(2):255-266
Entrepreneurial orientation (EO) is a strategic posture of an organization, and it is related to basic policies and practices for the development of entrepreneurial actions looking for creating competitive advantages. This study develops and tests a model of the relationship between entrepreneurial orientation and project success in Brazilian context. As quantitative research, a survey was used to collect data. A sample of 100 valid answers from project practitioners was treated through the structural equation modeling method. As research implications, the main result points out the positive correlation between the entrepreneurial orientation and the project success, contributing to the development of this research subject and helping to minimize the gap in the literature that addresses the relationship between project success and EO. In practical terms, understanding that innovativeness, risk taking, proactiveness, autonomy and competitive aggressiveness (the dimensions of the EO) can contribute to project success and can also indirectly impact on organizational performance, could help organizations get competitive advantage when developing correlate factors. Finally, the results suggest that practices of project management can be aligned to the firm's entrepreneurial orientation to enable firms to attain better results in their projects and generate a competitive advantage. On other hand, given the proportion of the impact of EO on project success (20.3%) identified in this study, it is critical that project management professionals expand their horizon to recognize other factors that affect project success. 相似文献
9.
《Advanced Powder Technology》2020,31(1):287-299
The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed. 相似文献
10.
采用Gleeble-3500热模拟试验机对30CrNi3MoV钢进行单向热压缩试验,研究了其在变形温度950~1150 ℃、应变速率0.01~10 s-1的热变形行为,构建了应变补偿型流变应力本构方程,并绘制出该钢的热加工图。结果表明,30CrNi3MoV钢真应力-真应变曲线有3种不同特征:高温小应变速率时,表现为典型的动态再结晶过程;低温小应变速率时,曲线为动态回复特征;应变速率较大时,应力随应变的增大而增大,无明显的峰值应力。采用5次多项式拟合构建的应变耦合流变应力本构方程具有高的精确度,采用该方程获得的预测值与试验值的平均相对误差为3.2%,相关性系数R值为0.993。从热加工图中得到试验钢最佳的热加工工艺参数范围是:变形温度为1020~1150 ℃、应变速率为0.03~0.35 s-1。 相似文献