综合先进技术的交通噪音评估(一)-以立体地理资讯系统为基础的区域噪音模型

为了解、组织及整理整个香港区域的道路交通噪音资料,从而确定、量化及分折交通噪音的严重性,再鉴定相关的噪音缓解措施,香港环境保护署综合了数种先进的技朮,包括地理信息系统、大型的电脑噪音模型、立体影像技朮等,自行开发了一套以立体地理资讯系统为基础的区域噪音模型。从这个系统和模型计算出来的交通噪音地图,加上利用地理信息系统軟件、人口分布的资料库和统计学方法的帮助,评估了整个城市总共有多少居民在那些区域受着多少交通噪音的影响。这些结果可以分析交通噪音的问题,继而决定未来噪音缓解设施及制定综合的计划,以应付这噪音问题。     

Feed/Seed比值对好氧生物处理效率的影响

好氧生物反应器的进料物（Feed）是经厌氧作用的消化污泥，而其接种体（Seed）是活性污泥。主要研究了四种Feed／Seed比值（1：0，3：1，1：1和0：1）对好氧生物处理效率的影响。对于Feed／Seed比值为1：0和0：1而言，污泥的TSS和VSS的去除率很低。而另外两种比值的实验结果表明，TSS和VSS的去除率均随Feed／Seed比值的增加而增加。对于Feed／Seed比值为3的生物反应器，28天的TSS和VSS的去除率分别达到了49％和50％。并且TSS和VSS的降解服从一级反应动力学。动力学降解常数（k）也随Feed／Seed比值的增加而增加。而且VSS的去除率略高于TSS。另外，硝化反应的发生导致好氧生物反应器中的硝酸根离子浓度的增加和pH的降低。     

ILC for non-minimum phase system

In this paper we propose a design method of an iterative learning controller (ILC) for a non-minimum phase (NMP) system by model-matching theory. The ILC consists of two learning filters acting on both the previous input signal and the previous error signal. To design the learning filters, we convert the convergence condition of the ILC into the model-matching problem and get the stable and proper learning filter by solving the Nevanlinna's algorithm. To show the usefulness of the proposed algorithm, some design examples are included.     

Adaptive tracking system for a manoeuvring target using images with correlated noises

An effective scheme is proposed for estimating the state parameters of a manoeuvring target from a noisy image sequence, providing the sequence contains correlated noises and the trajectory of the target is disturbed by an unknown acceleration. For the correlated noises, a first-order difference operator is applied to the original image sequence to generate an artificial measurement sequence with only uncorrelated white noises. For the unknown acceleration, a Kalman filter augmented by a semi-Markov process and the bayesian theory is applied to form an adaptive filter. In the proposed tracking system, the filter first generates an artificial measurement at each sampling time from the observation. It then utilizes an artificial measurement sequence up to the current time instance to predict the a posteriori probability of each possible acceleration state. The weighted average of acceleration, where the weight is the a posteriori probability, is applied to derive the optimal estimates of the state parameters. Several computer simulations with external force applied at unknown times are performed to demonstrate the applicability and superiority of the proposed system.     

Multipurpose controller synthesis in discrete LQG optimal systems

This paper presents a design algorithm to synthesize a discrete-time linear-quadratic-gaussian (LQG) optimal controller that simultaneously ensures (i) input–output decoupling; (ii) pole and zero placement; and (iii) robust stability in the presence of plant perturbation. Two weighting matrices Q(Z) and R(Z) of the quadratic cost functional are shaped to synthesize an optimal controller to achieve the stated design goals.     

Collapse behavior evaluation of hybrid thin-walled member by stacking condition

The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmentally-friendly aspect, the vehicle structure must be light weight in order to improve the fuel efficiency and reduce the tail gas emission. Therefore, the light weight of vehicle must be achieved in a securing safety status of crash. An aluminum or carbon fiber reinforced plastics (CFRP) is rep...     

Formation of interfacial brittle phases sigma phase and IMC in hybrid titanium-to-stainless steel joint

The microstructures of the brazed joints for commercially pure Ti and stainless steel were investigated by the applications of various filler alloys including Ag-, Ti-, Zr- and Ni-based alloys. Generally, the dissimilar joints between Ti and stainless steel were dominated by the Ti-based intermetallic compounds (IMCs), e.g. (Ti, Zr)2(Fe, Ni), TiFe, TiCu, and Ti2(Fe, Ni), due to a significant dissolution of Ti from the base metal. The (Fe-Cr) σ phase was also observed near the stainless steel due to a segregation of Cr into the interface region. This research demonstrates empirically that the brittleness of the Ti and stainless steel joint can not be avoided only by applying single braze alloy or single insert metal, and thus an introduction of additional suitable interlayer between the filler alloy and the base metal is necessary to prevent the brittleness of the joint.     

Efficient and secure source authentication scheme for multicast user authentication

Multicast technology application has been widely utilized in broadband internet. Source authentication is one of the most needs for many multicast applications transferring real-time information such as stream video and online news. Because multicast current services provided to the group members are changed dynamically, data transferring by a group member is not used by the recipient. In order to verify the identity of the sender who sent the packet and to make sure that the data have not been tampered, an optimized source authentication scheme has been proposed to transfer the authentication information not to the next-door packet. The proposed method for multiple packets authenticates the source with a limited number of electronic signatures. The proposed method can reduce overhead compared to the method by adding a digital signature for every packet. In addition, by sending the generated electronic signature to the first packet and the last packet, it prevents the loss of consecutive packets, as well as a source authentication can be provided in real-time services.     

Tenderization of Meat with Ginger Rhizome Protease

Beef steaks and sliced beef marinated with different levels of crude ginger extract were evaluated for the tenderness and structural changes. A significant (P<0.05) enhancement of tenderness with increasing amounts of ginger extract was observed at low levels of extract (0, 0.05, 0.1, and 0.2 mL/6.5 cm² for the steaks; 0, 0.25, 0.5, and 1 mL/lOOg for the sliced beef), whereas further improvement of tenderness at more than 0.2 mL/6.5 cm² or 1 mL/lOOg was minimal. Electron microscopy of the treated beef revealed the preferential degradation of thin filaments in the I-bands, resulting in extensive fragmentation of myofibrils. Thus, ginger rhizome protease is an effective meat tenderizer and the tenderization is achieved through preferential degradation of thin filaments.