Forecast Combination Under Heavy-Tailed Errors

Forecast combination has been proven to be a very important technique to obtain accurate predictions. In many applications, forecast errors exhibit heavy tail behaviors for various reasons. Unfortunately, to our knowledge, little has been done to deal with forecast combination for such situations. The familiar forecast combination methods such as simple average, least squares regression, or those based on variance-covariance of the forecasts, may perform very poorly. In this paper, we propose two nonparametric forecast combination methods to address the problem. One is specially proposed for the situations that the forecast errors are strongly believed to have heavy tails that can be modeled by a scaled Student's t-distribution; the other is designed for relatively more general situations when there is a lack of strong or consistent evidence on the tail behaviors of the forecast errors due to shortage of data and/or evolving data generating process. Adaptive risk bounds of both methods are developed. Simulations and a real example show superior performance of the new methods

Neural Evolution for Augmenting Topologies in Printed Neuromorphic Circuits

In the context of fast-paced advancements in the Internet of Things and artificial intelligence, the demand for custom solutions in emerging fields like smart packaging and smart bandages has risen significantly. These innovative applications require electronics that are not only ultra-low-cost but also highly flexible and customizable, particularly for edge processing tasks. Traditional silicon-based electronics often fall short in offering cost-effectiveness. In contrast, printed electronics have emerged as a powerful alternative. They use additive manufacturing techniques to create custom electronic circuits at ultra-low cost. These electronics are particularly versatile, with a choice of materials and substrates contributing to notable flexibility and bio-compatibility. To further equip them with computational abilities, there is an increasing interest in printed neuromorphic circuits. These circuits effectively merge the benefits of neuromorphic computing with the capabilities of printed electronics. Nevertheless, the intrinsic constraints of printed electronics, namely large feature sizes and notably reduced integration density, pose challenges for compact application areas. To address these challenges, we propose a method inspired by the Neural Evolution for Augmenting Topologies algorithm. Unlike traditional gradient-based optimization methods, such as pruning, our approach simultaneously optimizes the learnable parameters and the topology structure of printed neuromorphic circuits, thereby facilitating a reduction in circuit area. Through experiments conducted on 11 different datasets, we demonstrate the effectiveness of our approach. Experimental results reveal that, with the proposed approach, 3.1× reduction of the circuit area can be realized while maintaining 100% of classification accuracy of the gradient-based pruning method

Can Steel Slag Be Used as an Aggregate in Concrete and How? A Technical Approach by and Testing and Theoretical Molding

Steel slag is the molten byproduct from steelmaking operations that is subsequently air-cooled for use. It has been used in cement manufacture and as unbound granular materials in construction. While numerous studies have revealed that concrete containing steel slag aggregate possesses good mechanical properties, and slag, as a byproduct, is cheaper than virgin aggregates, its practical use in Portland cement concrete is currently a forbidden area in the construction practices. What is the practicality, where is the crux of converting research results into to real production, and how to build the bridge between the laboratory experiment and the end products? Based on the philosophy of slag utilization, i.e., laboratory testing, field demonstration, and criteria establishment, the questions to be answered includes (1) two distinct laboratory test methods to determine the expansion force generated by slag particles; (2) conversion of the expansion force of mass slag aggregate to the expansion force of single slag particle; (3) mechanical disruption model of slag failure; and (4) usability criteria for the use of steel slag in a rigid or restrained matrices. The paper introduced the answers for the first two questions; and provides the mechanical model and criterion deduction to answer the other two questions that lead to criteria and specification establishment. Read More: http://ascelibrary.org/doi/abs/10.1061/9780784479827.025 This paper was presented at the 2016 Construction Research Congress in San Juan, Puerto Rico in May 2016

Expansion des laitiers d’aciérie : à l’ouest, il y a du nouveau !

Contrairement aux laitiers de hauts fourneaux qui sont volumétriquement stables et faciles à utiliser en construction routière notamment, les laitiers d’aciérie contiennent de la chaux libre non hydratée en proportion variable qui peut occasionner leur expansion. Ainsi, afin d’envisager une exploitation maîtrisée de ces laitiers, il est indispensable d’en évaluer chaque type, selon son origine et les traitements qu’il a subi, afin de déterminer son instabilité volumétrique et son potentiel d’expansion. Or aujourd’hui, en l’absence de critères quantifiés permettant d’orienter les laitiers d’acierie vers des usages appropriés, ceux-ci demeurent peu utilisés. Les Etats-Unis ont sur ce point une longueur d’avance. Cet article présente les résultats d’études sur l’expansion volumétrique des laitiers d’acierie visant à élaborer des critères susceptibles de servir d’indicateurs pour l’utilisation de ces laitiers en tant que matériaux granulaires

Development of Lateral Flow Fluorescence Assay for the Detection of Trypanosoma

Trypanosoma such as Trypanosoma brucei and Trypanosoma cruzi, the causative agents for African sleeping sickness and Chagas disease, respectively, have important influence on human health. The methods such as microscopic examination, immunological methods, and molecular methods are used for the identification and detection of Trypanosoma, but none of these methods are ideal to mass screening of samples such as onset of outbreak, epidemiological surveys, and blood unit screening. Therefore, there is a need for an assay which can rapidly, sensitively and specifically detect Trypanosoma. In this study, Ru(bpy)32+-doped silica nanoparticles (RuSNP) were used to target nucleic acid sequences in a lateral flow fluorescent assay. This assay was developed to improve the sensitivity and lower the limit of detection as compared to the traditional lateral flow assay. The assay targeted both the spliced leader sequence as well as the polyA tail of the mRNA. The surface of spherical RuSNP was modified by glycidoxypropyl trimethoxysilane (GOPTMS). Amine-terminated oligonucleotides as a bioreceptor were immobilized onto the RuSNP via the interaction between the NH2 and the epoxy group of the GOPTMS. The conjugate complexes formed were immobilized on the conjugate pad, and the capture oligonucleotides used for test and control lines were immobilized on the nitrocellulose membrane. The effects of the amount of RuSNP, GOPTMS, amine-capped oligonucleotides, and capture oligonucleotides on the test line on the performance of the test strips were investigated and optimized. The fluorescence intensity was evaluated by using a fluorescent microplate reader. The experimental results showed that the nucleic acid sequence-based and RuSNP-labeled lateral flow assay was very sensitive compared with the gold-labeled test strips and the chemiluminescent test strips we developed previously, and that the limit of detection (LOD) of the test strips developed is 0.4 fmol. The LOD can further be reduced about one order of magnitude when dipstick format was used

Impact of Bt Cotton on the Farmer's Livelihood System in China

In order to analyze the impacts of Bt cotton on the farmers' livelihood system, we interviewed 169 farmers and extension personnel in the main cotton production areas in Hebei province in the year 2002 and 2003. An integrative method was used in which a multidisciplinary approach was employed including agronomy, economics and sociology. The results showed that the application of Bt cotton increased the cotton growing area as well as farmers' income. For 67% of the farmers interviewed, cotton area has been continuously increasing since 1997. The cotton net margin in one cropping cycle came out to be higher than the combined net margins of wheat and corn in two cropping cycles. The income from cotton played a significant role in the investment to education, leisure and health care. The socio-economic impacts of cotton production are nevertheless not yet optimal because there were still many factors limiting them. Lack of labor and land were the main limiting factors. Productivity is restrained by the high price of Bt cotton seeds which pushed farmers to keep seeds from their own cotton production (42% of the farmers in 2002 and 2003). Farmers are still lacking technical command in using Bt-cotton: 78% of the farmers admitted that while more than 94% of the farmers complained not getting information from local extension and technical services. More success in using Bt-cotton calls upon going beyond providing seeds and asks for continuous assistance from research and extension department, notably to achieve a full knowledge of the Bt-cotton characteristic so as to optimally integrate it into the farmers' system.China; Bt Cotton; biotechnologies; impact evaluation; Livelihood

Research of Proxy Cache Algorithm in Multi-media Education System

Multi-media education system is more and more widely used in all levels of education. In order to decrease cost of multi-media system and keep efficiency with increasing multi-media materials, proxy cache algorithm has been widely studied. Based on analysis of existing research of proxy cache results, an improved proxy coaching strategy of prefix cache and postfix merging is proposed. The strategy can dynamically adjust prefix cache size with the object access change. A more effective method of steaming merging has been proposed with multicast used in postfix portion. The results show that the improved strategy can effectively utilize proxy cache resource, shorten time delay and save band width