Beamformer Based on Quaternion Processes

In this chapter, the problem of quaternion beamformer based on linear and widely linear hypercomplex processing is investigated in scenarios, where there exist one signal and one interference that are uncorrelated. First, we introduce brief information about the quaternion algebra and a quaternion model of linear symmetric array with two-component electromagnetic (EM) vector-sensors is presented. Based on array’s quaternion model, a quaternion MVDR (QMVDR) beamformer is derived and its performance is analysed. Second, we propose the general expression of a quaternion semi-widely linear (QSWL) beamformer and derive its useful implementation and the array’s gain expression. Finally, we give the main results of Monte Carlo simulation

Quasi-homomorphisms of quantum cluster algebras

In this paper, we study quasi-homomorphisms of quantum cluster algebras, which are quantum analogy of quasi-homomorphisms of cluster algebras introduced by Fraser. For a quantum Grassmannian cluster algebra $\mathbb{C}_q[{\rm Gr}(k,n)]$, we show that there is an associated braid group and each generator $\sigma_i$ of the braid group preserves the quasi-commutative relations of quantum Pl\"{u}cker coordinates and exchange relations of the quantum Grassmannian cluster algebra. We conjecture that $\sigma_i$ also preserves $r$-term ($r \ge 4$) quantum Pl\"{u}cker relations of $\mathbb{C}_q[{\rm Gr}(k,n)]$ and other relations which cannot be derived from quantum quantum Pl\"{u}cker relations (if any). Up to this conjecture, we show that $\sigma_i$ is a quasi-automorphism of $\mathbb{C}_q[{\rm Gr}(k,n)]$ and the braid group acts on $\mathbb{C}_q[{\rm Gr}(k,n)]$

Barriers to the transition towards off-site construction in China: An Interpretive structural modeling approach

Off-site construction (OSC) has been recognized as an approach to transform the construction sector from a labor–intensive to a modernized and green industry. Despite a number of advantages, the development of OSC still remains its infancy in China due to various interactive barriers. Some studies have been conducted to explore the barriers to the OSC adoption. However, very few studies attempted to investigate the complex interrelationships among these barriers. In order to fill this gap, this study adopts Interpretive Structural Model (ISM) technique to explore the interrelationships amongst barriers to the OSC adoption in China. Firstly, critical barriers were identified through literature review and semi-structured interviews with various stakeholders. Then, the overall structure amongst barriers was revealed through ISM technique. By using the Matriced’ Impacts Croise's Multiplication Appliquée a UN Classement (MICMAC) technique, the barriers were classified into four groups according to their driving-power and dependence power. The results indicate that specific attentions should be given to inadequate policy and regulations, lacking knowledge and expertise, dominated traditional project process as well as low standardization. The research findings provide valuable information for policy-makers on the overall structure amongst barriers. These results shed lights on effectively developing measures to facilitate the OSC adoption in the construction sector

Efficient production of pullulan by Aureobasidium pullulans grown on mixtures of potato starch hydrolysate and sucrose

AbstractPullulan is a natural exopolysaccharide with many useful characteristics. However, pullulan is more costly than other exopolysaccharides, which limits its effective application. The purpose of this study was to adopt a novel mixed-sugar strategy for maximizing pullulan production, mainly using potato starch hydrolysate as a low-cost substrate for liquid-state fermentation by Aureobasidium pullulans. Based on fermentation kinetics evaluation of pullulan production by A. pullulans 201253, the pullulan production rate of A. pullulans with mixtures of potato starch hydrolysate and sucrose (potato starch hydrolysate:sucrose=80:20) was 0.212h−1, which was significantly higher than those of potato starch hydrolysate alone (0.146h−1) and mixtures of potato starch hydrolysate, glucose, and fructose (potato starch hydrolysate:glucose:fructose=80:10:10, 0.166h−1) with 100gL−1 total carbon source. The results suggest that mixtures of potato starch hydrolysate and sucrose could promote pullulan synthesis and possibly that a small amount of sucrose stimulated the enzyme responsible for pullulan synthesis and promoted effective potato starch hydrolysate conversion effectively. Thus, mixed sugars in potato starch hydrolysate and sucrose fermentation might be a promising alternative for the economical production of pullulan