Improving locality in binary representation via redundancy.

Binary representation suffers from the problem of positional dependence, where the amplitude of phenotype variation is dependent on the position of the altered genotype bits. However, this is contrary to conventional variation operations that treat each genotype bit equally. Positional dependence can be attributed to the poor locality, which results in neighboring genotypes having low correlation in the phenotype space, reducing the effectiveness of systematic local search and evolutionary search based on small mutation steps. For this purpose, this paper will propose an alternative genotype-phenotype mapping for binary representation that introduces redundancy into the mapping and removes the exponential orderings between the alleles, hence improving the locality between the genotype and phenotype search space. Empirical study conducted based on distribution, locality, and mutation innovation revealed key algorithmic characteristics of the proposed code, and its practicality is validated by comparative studies based on different benchmark optimization problems. Possible approaches to resolve the overrepresentation problem due to redundancy will be suggested, exhibiting its flexibility and variability in implementation.     

Effect of extraction techniques and conditions on the physicochemical properties of the water soluble polysaccharides from gold kiwifruit (Actinidia chinensis)

The extraction of nonstarch polysaccharides from fruits and vegetables has received much attention recently in terms of their utilisation in functional food systems. In New Zealand kiwifruit production is one of the major fruit growing exploits. This paper explores the potential extraction techniques which may be employed to extract water soluble polysaccharides from kiwifruit material, in an attempt to utilise this commodity as an added value food ingredient. Crude water soluble polysaccharides of fresh gold kiwifruit were extracted under different extraction techniques (acid, hot water and enzyme) and conditions (time, temperature and concentration). The recovery of water soluble polysaccharide fraction (WSP), chemical composition, and their rheological behaviour were examined. The extraction technique had a significant effect on the WSP yield, galacturonic acid content, as well as the viscosity. Enzymatic extraction method yielded higher WSP and galacturonic acid than water and acid extraction, but this fraction exhibited lower viscosity. Acid extracted WSP yield decreased with increasing temperature and time. In contrast, water extracted WSP yield increased with increasing temperature and time. The selected extraction parameters for acid extraction were temperature 50 °C, extraction time 60 min, and 1:6 kiwifruit puree to acid solution ratio. The water extraction optimum parameters were 25 °C, 30 min and 1:4 puree to water ratio and 25 °C, 30 min with medium concentration for enzymatic extraction. The WSP viscosity and galacturonic acid content was maximum under these extraction conditions.     

下一代产品所需的过流和过压电路保护

防静电、防过电流和过电压冲击是工程师设计电子产品时必须考虑的一个问题。本文集中探讨了目前市场上所有的电路保护技术,并展望了未来电路保护器件的发展方向。     

Ambiguity-function-based techniques to estimate DOA of broadband chirp signals

Various methods are available to perform direction-of-arrival (DOA) estimation for random sources. However, the work on DOA estimation of deterministic sources, such as broadband chirp signals, is quite limited. This paper proposes two novel methods for broadband chirp DOA estimation (BCD), namely the incoherent broadband chirp DOA estimation (BCD-I) and coherent broadband chirp DOA estimation (BCD-C). The proposed methods exploit the time-frequency structure of the chirp signal via the ambiguity function, which converts the absolute time and frequency of the chirp signal into relative time lag and frequency difference. The algorithms can be applied to arrays of any aperture size and arbitrary chirp rate signals. The signal frequency of the source can be higher than the conventional array design frequency, and the number of sources can be greater than the number of sensors as long as the signals are separable in the ambiguity function plane. These methods can be applied to single or multiple chirps with the same or different chirp rates. The performance analysis shows that our algorithms generally provide improvements in the DOA estimation of the broadband chirp sources.     

A visionary and conceptual macroalgae-based third-generation bioethanol (TGB) biorefinery in Sabah,Malaysia as an underlay for renewable and sustainable development

Several biofuel candidates were proposed to displace fossil fuels in order to eliminate the vulnerability of energy sector. Biodiesel and bioethanol produced from terrestrial plants have attracted the attention of the world as potential substitute. However, due to food vs. fuel competition as well as land consumption of these biofuel, they have brought much controversy and debate on their sustainability. In this respect, cultivation of macroalgae such as seaweed at sea water which does not expend arable land and fertilizers provides a possible solution for this energy issue. Carbohydrates derived from seaweeds contain hexose sugars which are suitable materials for fermentation to produce ethanol. Therefore, it is possible to produce fuel ethanol from seaweeds. The potential and prospective of seaweeds to play the role as a sustainable energy provider are demonstrated in this paper. This study offers a conceivable picture of macroalgae-based third-generation bioethanol biorefinery to stimulate the initiation of the exploration in the related field.     

On the mechanics of wire cutting of cheese

The wire cutting process is used in the food industry during the manufacture and testing of products. The cutting process involves fracture as well as large strain deformation and surface friction. This paper investigates the mechanics of the wire cutting process of cheese through a combination of experiments, theory and finite element simulations. The experiments revealed that there was secondary damage on the cut surface, thus a higher fracture energy would be consumed than the common assumption of a single crack propagation. The numerical simulations showed that there was a six-fold change in the strain rate when wire diameters of 0.25  to 2 mm are used. This strain rate effect was modelled through a modification of a previous theoretical analysis of the wire cutting process. The numerical models were also used to predict the cutting forces using two failure criteria: critical strain, which was applied to the initiation of cracking, and a cohesive zone model to simulate crack propagation. Both criteria showed reasonable success in predicting the cutting forces, particularly for cuts made with small wire diameters.     

Linear prediction approach for efficient frequency estimation of multiple real sinusoids: algorithms and analyses

Based on the linear prediction property of sinusoidal signals, two constrained weighted least squares frequency estimators for multiple real sinusoids embedded in white noise are proposed. In order to achieve accurate frequency estimation, the first algorithm uses a generalized unit-norm constraint, while the second method employs a monic constraint. The weighting matrices in both methods are a function of the frequency parameters and are obtained in an iterative manner. For the case of a single real tone with sufficiently large data samples, both estimators provide nearly identical frequency estimates and their performance approaches Crame/spl acute/r-Rao lower bound (CRLB) for white Gaussian noise before the threshold effect occurs. Algorithms for closed-form single-tone frequency estimation are also devised. Computer simulations are included to corroborate the theoretical development and to contrast the estimator performance with the CRLB for different frequencies, observation lengths and signal-to-noise ratio (SNR) conditions.     

Complex-valued forecasting of wind profile

This paper presents a novel approach for the simultaneous modelling and forecasting of wind signal components. This is achieved in the complex domain by using novel neural network algorithms and architectures. We first perform a signal nonlinearity and component-dependent analyses, which suggest the use of modular complex-valued recurrent neural networks (RNNs). This RNN-based modelling rests upon a combination of nonlinearity, complexity and internal memory and allows for the multiple step ahead forecasting of the wind signal in its complex form (speed and direction). The approach is first verified on benchmark Data Set A (NH₃ laser data) of the Santa Fe Time Series Prediction Competition together with artificial data generated by chaotic Mackey–Glass equations, and then applied to the real-world wind measurements. Simulations support the proposed architecture and algorithms.     

1300-nm pulsed fiber lasers mode-locked by purified carbon nanotubes

For the first time, we demonstrate a novel passively mode-locked fiber laser operating at 1300 nm using purified single-walled carbon nanotubes (CNTs) as a saturable absorber. The saturable absorber incorporates diameter-controlled CNTs with peak absorption /spl sim/1300 nm, guaranteeing mode-locking over the same wavelength region. The ring laser uses praseodymium-doped fiber as a gain medium. The pulse repetition rate is 3.18 MHz, and the spectral half-width is 0.15 nm. Dual-wavelength mode-locking is also demonstrated with a channel spacing of 1.1 nm.     

Limited economic evaluation to assess the effectiveness of a university-wide office ergonomics program

The objective of this research was to evaluate the effectiveness and provide a limited economic evaluation of an office ergonomics program at a major university from 1995 to 2007. The relationship between office-related recordable injuries, reported lost time, severity of these injuries, and the Workers' Compensation (WC) paid was analyzed and the corresponding incident cost was calculated. Two major datasets analyzed were OSHA 200/300 logs (1991-2007) and WC claims paid (1999-2007). Since the beginning of the office ergonomics program in 1995 and through 2007 (13-year period), the number of office cumulative trauma disorder (CTD) cases decreased by 53%. Since the official start (in 1999) of a 50-50 cost share agreement for office equipment purchases between the university's Safety and Health Department (SHD) and the university departments evaluated, it was observed that the incident rate decreased by 63%, Total Days Away/restrict or Transfer (DART) rate decreased by 41%, Lost Time Case (LTC) rate decreased by 71% and office-related carpal tunnel syndrome decreased by almost 50%. The long-term goal of this research is to demonstrate the self-sustainability of an office ergonomics program by showing that equipment costs are eventually offset by a decrease in WC claims paid and lost time from office-related injuries and illnesses. While limited, this research helps in cost-justifying the implementation of future office ergonomics programs for large organizations.