基于间隔率和遗传算法的多资源均衡优化研究

为解决传统编码方式易产生无效解的问题,提出基于间隔率的编码与解码方法,从而避免在交叉、变异等遗传操作中出现违反作业间逻辑关系的情况。由于方差更能体现项目在各时刻资源需求的不均衡程度,为此建立了以资源方差最小为目标函数的多资源均衡优化模型。结合案例,详细叙述了该算法的设计参数和应用步骤,结果表明,该方法较传统编码方式具有收敛速度快、优化效果明显等优点,从而验证了该方法的可行性和有效性。     

Water Resources Liability Measurement and the Driving Factors of Water Resources Liability Intensity

Water resources liability (WRL) is the responsibility and obligation assumed and repaid after human activities cause excessive consumption and damage to water resources. It is the creditor's right and debt relationship between the economy and natural environment based on water resources. With the intensification of water competition and the deterioration of water ecology, it is urgent to accurately calculate the real occupation of water resources by national and regional economic activities. From the perspective of sustainable utilization of water resources, this study constructs an accounting model of WRL and water resources liability intensity (WLI), analyzes the spatial and temporal characteristics of WLI, and discusses the driving factors of WLI. The results reveal that the total amount of WRL in China experienced a decreasing trend from 2012 to 2019. The increase in available water resources and the decrease in total water demand are the direct reasons for the decrease in WRL. China's average WLI experienced a downward trend, indicating a significant improvement in water use efficiency. The WLI was higher in the western region and lower in the eastern region. In terms of regional differences, the overall spatial differences of WLI were in the process of continuous adjustment. The analysis of the driving factors of WLI reveals that the urbanization rate and the degree of economic openness had a significant driving effect on reducing WLI. The WLI in China presented an inverted N-shaped Kuznets curve, and most of the regions were between the first and second inflection points.

     

基于在线评论情感分析的改进协同过滤推荐模型

针对在线中文评论中用户主观意见的不确定性,提出一种基于不确定理论的情感分析模型,并结合情感分析模型设计了个性化推荐算法。采用分词工具ICTCLAS和IKAnalyzer预处理在线中文评论,并基于情感词典(HowNet)计算特征词的点互信息值;应用不确定变量与不确定集设计情感分析模型;根据情感分析模型设计新的最近邻居搜索方法并产生推荐。在两个真实数据集上进行试验,试验结果表明,该方法能够有效改进推荐结果的准确率,缓解数据稀疏问题。     

An adaptive consensus method for multi-attribute group decision making under uncertain linguistic environment

For a multi-attribute group decision making (MAGDM) problem, the so-called consensus reaching process is used to achieve an agreement among experts and finally make a common decision. Unfortunately, so far the consensus models for MAGDM haven’t been completely studied, especially for MAGDM under uncertain linguistic environment. The disadvantages of most existing consensus models could be summarized into 3 aspects. (1) In most existing consensus models, all the experts’ opinions are weighted equally important, and/or all the experts’ weights are treated statically. (2) Most of the interactive consensus methods are lack of effective feedback mechanism, while the automatic ones also have some defects, such as the lack of pertinence in adjustment process and the inability to reflect the subjective opinions of experts. (3) Also the comparison methods for uncertain linguistic variables therein are far from perfect, which require either complicated computing process or may cause non-distinguishable cases. In order to solve the above problems and obtain final decision results more efficiently, an interactive method with adaptive experts’ weights and explicit guidance rules for MAGDM under uncertain linguistic environment is developed. Our contributions can be summarized as follows. (1) Based on the definitions of closeness and consensus indices, a non-linear programming model is constructed to dynamically adjust the experts’ weights by maximizing the group consensus. (2) A targeted feedback mechanism including identification rules and recommendation rules is designed to guide the experts to modify their opinions more precisely and effectively. (3) A more appropriate method for comparing uncertain linguistic variables named dominance index is proposed, which can simplify the calculation process significantly. Finally, an illustrative example proves that the proposed consensus method is feasible and effective, and a detailed comparison and analysis highlights the advantages and characteristics of this method.     

Equity warrants pricing model under Fractional Brownian motion and an empirical study

In this paper, we construct equity warrants pricing model under Fractional Brownian motion, deduce the European options pricing formula with a simple method, then propose the warrants pricing formula, and extend it to cover equity warrants on a stock providing dividends. Finally, taking Changdian warrant in Chinese stock market as an example, we illustrate that the results based on the new warrants pricing formula is more accuracy than the classical results based on traditional pricing model.     

Technology-environment-economy assessment of high-quality utilization routes for coke oven gas

Coke oven gas (COG) is an important energy resource that rich in hydrogen and methane, which is conventionally used for industrial heating but is embarking on high-quality utilization routes to produce bulk energy and materials. Previous work emphasized the comparison of COG utilization with external competitors but has limited understanding of the internal competitiveness of different COG utilization routes, making it impossible to scientifically guide the high-quality utilization of COG. This study proposed a technology-environment-economy assessment framework to compare the competitiveness of six high-quality COG utilization routes called COG to electricity (COGTE), COG to methanol (COGTM), COG to hydrogen (COGTH), COG to synthetic natural gas (COGTSNG), COG to synthetic ammonia (COGTSA), and COG to olefins (COGTO). The framework employed the life cycle assessment method based on an economic functional unit to calculated individual indicators and used the entropy weight method to integrate these indicators to a comprehensive score. The results show that energy consumption, water consumption, and carbon emission are critical defects of COGTSNG, COGTM, and COGTE, respectively. Net present value rate, internal rate of return, and dynamic payback period are common but differentiated disadvantages of the five COG utilization routes other than COGTO with the current market price, which are the main factors of their weaker comprehensive competitiveness. COGTO is expected to be the most promising high-quality COG utilization route thanks to its excellent competitiveness, handsome market demand, and special policy preferences. In addition to COGTM, any of the other five COG utilization routes are likely to be most competitive when raw material and product prices fluctuate by 25%, which suggests that the investment should be tailored to local specific prices, demand, and policies.     

Tabu search algorithms for minimizing total completion time on a single machine with an actual time-dependent learning effect

Natural Computing - In this paper, we investigate a single machine problem with actual time-dependent learning effect considering unequal release times, where the objective is to minimize the total...     

基于计算机软件测算的我国人口预期寿命的影响因素分析

本文选择我国各地区的人均寿命作为因变量,分析影响人口预期寿命的因素,并对各因素的作用大小进行讨论。总地来看,卫生机构、各地区的单位环境污染情况、教育支出情况对人均寿命起着大小不同的作用。通过计算机软件分析得出要提高人们的寿命,最重要的是提高人们的生活水平,但人们生活水平并不是能在短暂时间就能进行大幅度提高的。而在当前经济水平下,还需要大力发展我国的教育事业。     

Carburization of high-temperature steels: A simulation-based ranking of carburization resistance

Carburization is a failure mechanism affecting equipment, such as furnace tubes, operating at high temperatures. Carburization simulations were carried out for the heat-resistant steels referred to the API-530 standard by applying a model for carbon diffusion with the concurrent formation of alloy carbides. The calculated carbon and carbide volume fraction profiles were validated experimentally. The carburization layer is composed from M₂₃C₆ and M₇C₃ carbides. The time required for the carburization front to reach the mid-thickness of the tubes was used to characterize carburization resistance. The austenitic grades exhibit a higher carburization resistance than the ferritic grades at all temperatures. In the ferritic grades, alloy composition has a stronger effect at lower service temperatures (600 °C) where carburization resistance increases with Cr and Mo content. The acceleration of diffusion at high temperatures (800 °C) dominates the composition effects on carbon diffusion, and the carburization front is controlled by the formation of carbides, which in turn depends on the available amount of Cr in the steel. In the austenitic grades, the highest carburization resistance is exhibited by the stabilized grades 321 and 347 due to formation of TiC or NbC carbides respectively. Regarding the non-stabilized grades, carburization resistance is raised by addition of Mo (316 vs 304) and lower carbon (316L vs 316). The results of this study can be used for material selection for carburization resistance and for planning maintenance procedures for the timely replacement of tubes.