Health risks of residential wood heat

The resurgence in the use of wood in the United States for residential heating has been accompanied by a dramatic increase in deaths and injuries from residential fires. Toxic materials present in woodsmoke also appear to present a significant public health hazard. As a result of these factors, production of residential wood heat can be up to two orders of magnitude more hazardous than generation of an equivalent amount of electric energy at a coal-fired power plant. Proper care in installation and operation of wood stoves, as well as technological innovations that control wood-stove emissions, can greatly reduce the health and safety hazards of residential heating with wood.     

一种改进的多学习教与学优化算法

针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。     

美国新潮:通过明星的嘴和脸来环保

在纽约,人们不得不尝试采取各种形式来推进环境保护工作的进程,八仙过海各显其能.去年7月4日华盛顿庆祝国庆节的游行中,我就亲眼看到一个宣传环保的队伍,队中的每个人都拿着一个垃圾袋,边走边收集游行者和观众丢弃的易拉罐,成为国庆节游行的一个亮点.