众文网1.lightgbm具体有什么优势?
优势如下：
1）更快的训练速度和更高的效率：LightGBM使用基于直方图的算法。
2）更低的内存占用：使用离散的箱子（bins）保存并替换连续值导致更少的内存占用。
3）更高的准确率（相比于其他任何提升算法）：它通过leaf-wise分裂方法产生比level-wise分裂方法更复杂的树，这就是实现更高准确率的主要因素。然而，它有时候或导致过拟合，但是我们可以通过设置|max-depth|参数来防止过拟合的发生。
4）大数据处理能力：相比于XGBoost，由于它在训练时间上的缩减，它同样能够具有处理大数据的能力。
5）支持并行学习。
2.《光的色散》小论文800字
1、三棱镜，prism，白光经过三棱镜的棱，会产生色散，dispersion;
2、色散出来的光是按频率严格排列而成；
3、这些光不能再进一步色散，这些光叫做单色光，monochromatic light。
4、按频率排列的原因是：
A、其实不存在白光，白光是所有光的混合；
B、正因为不存在白光，所以平时所说的水、玻璃的折射率全是糊弄人的；
C、色散揭示了同一种玻璃，对于不同频率的光有不同的折射率，不存在
一个对白光的统一的折射率。
D、其实，更进一步，还会发现，不同偏振方向还有不同折射率。
E、再进一步，还会出现旋光现象Optical rotation。
楼主若按着A、B、C、D、E 这五点仔细展开，写上几十页，甚至一本书，
是轻而易举的事情。
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3.如何看待微软新开源的LightGBM
非常赞的工作，实现了和XGBoost不一样的搜索策略，所以在算法效果上并不是完全一样。
- XGBoost在单机默认是exact greedy，搜索所有的可能分割点。分布式是dynamic histogram，每一轮迭代重新estimate 潜在split candidate。
- LightGBM和最近的FastBDT都采取了提前histogram binning再在bin好的数据上面进行搜索。在限定好candidate splits，- 主要的速度提升似乎来自于两点。
一个是搜索的时候选取delta比较大的叶子扩展。第二个是pre-bin之后的histogram的求和用了一个非常巧妙的减法trick，省了一半的时间。
在算法和效果上面最近比较多的工作都开始基于提前限定分割点的近似算法然后快速求histogram。 这一类算法的潜在问题是限制了分割点只能是一开始的定下来的潜在这些。
不知道这一点对于实际应用的影响会有多大。理论上数据越多，树越深的时候，需要的潜在分割点越多，可能需要根据训练来动态更新潜在的分割点。
在算法上面采用delta比较大的扩展方向可以集中搜索提高比较重要的区域。一个潜在的问题是可能会忽略掉一些未来有潜力的节点。
当然这些讨论都和具体的应用场景有关。个人觉得exact greedy和histogram方法的还会共存一段时间。
或许可以比较好的在系统上面对这两个一起支持在系统上面因为集中做针对叶子的分割，似乎会对于数据集的random access有一定的要求。如果不shuffle data的情况下可能会有cache 的问题。
这个数据结构是一个有趣的问题非常值得学习，机器学习系统优化是非常重要的方向。希望可以看到越来越多这样实际的工作。
4.张鉴的主要论文
1. Jian Zhang, Qing-An Huang and Wei-Hua Li,“An ICP etch model based on time multiplexed deep etching”,20th Congress of the International Commission for Optics,SPIE Conference, Vol.6032, Aug., 2005.2. Jian Zhang, Qing-An Huang and Wei-Hua Li,“Study of lag effect in LPHD plasma etching of Si for MEMS applications by variable time steps in numerical methods”,20th Congress of the International Commission for Optics,SPIE Conference, Vol.6032, Aug., 2005.3. Jian Zhang, Qing-An Huang, and Wei-Hua Li, “A Novel Model for Surface Evolvement and Footing Effect Simulations in DRIE Fabrications”,the First Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems 2006, IEEE Xplore4. Jian Zhang, Qing-An Huang and Wei-Hua Li, “A Novel Model for Surface Evolvement and Footing Effect Simulations in DRIE Fabrications”, Review of Advancements in Micro and Nano Technologies (in press)5. Jian Zhang,Qing-An Huang, and Wei-Hua Li, “Simulations for Surface Evolvement and Footing Effect in ICP DRIE Fabrications” Journal of Physics: Conference Series Vol.34, 20066. Jian Zhang,Qing-An Huang, and Wei-Hua Li “Modeling and simulations of DRIE including a footing effect”,International Journal of Computational Materials Science and Surface Engineering Vol.2, No.3-4, 2009, 302-3117. Jian Zhang, Ming-Wu Yang, Xiao-Xiong He and Hao-Chen Qi “Primary Optical System Designing for Optimization of Light-emitting Diode Packages” Optoelectronics Letters (Springer) accepted8. Jian Zhang, Zhi-wen Hu, Hao-chen Qi, Cheng-yue Liu “Primary Optical System Designing for Optimization of Light-emitting Diode Packages” The 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT 2008): Advanced Optical Manufacturing Technologies. Proceedings of the SPIE, Volume 7282, pp. 72821H-72821H-5 (2009).9. HU Zhi-wen, ZHANG Jian, Scientific CCD Camera Caused Biased Estimates of low-light-level Quantitative Fluorescence Imaging Measurement, The 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT 2008): Optical Test and Measurement Technology and Equipment. Proceedings of the SPIE, Volume 7283, pp. 72832Z-72832Z-5 (2009).10. Dongliang Xu, Jian Zhang*Corresponding author, “A Novel 3-D Topography Model for Micro-Manufacturing”, Applied Mechanics and Materials, 2010, Vol.34-35, 477-481.11. Dongliang Xu, Jian Zhang*Corresponding author, “Modeling and Simulating for 3-D Micro-Manufacture Process”, International Conference on Solid-State and Integrated Circuit Technology, Proceedings, ICSICT, 2010 (accepted)12.张 鉴，戚昊琛，徐栋梁，胡智文，一种可用于硅刻蚀工艺模拟的三维表面演化算法，电子学报， Vol.39, No.8, 201013.张 鉴，黄庆安，李伟华，“固定宽度结构等离子体刻蚀中Lag效应的数值模拟”，传感技术学报，Vol.19,No.1,200614.张 鉴，黄庆安，李伟华，“MEMS工艺中反应离子深刻蚀硅片的数值模型研究”，传感技术学报，Vol.19, No.5, 200615.张 鉴，黄庆安，李伟华，“电感耦合等离子体（ICP）深刻蚀的模型与模拟” ，仪器仪表学报，Vol.27, No.10, 200616.张 鉴，黄庆安，李伟华，“一种可用于Footing效应模拟的ICP刻蚀模型” ，仪器仪表学报，Vol.28, No.12, 200717.张 鉴，何晓雄，刘成岳，戚昊琛，“基于线算法的ICP深反应离子刻蚀模型”，真空科学与技术学报，No.5,200818.张 鉴， 吕 明， 赵 强. “应用线算法的SU-8胶光刻过程模拟”. 固体电子学研究与进展， 录用19.张 鉴，杨明武等，“LED环氧树脂封装的光学设计与模拟”，合肥工业大学学报 自然科学版，Vol.31, No.10, 200820.张 鉴，方帅，胡智文，许晓琳，“LED封装的一次光学系统优化设计”，半导体光电，Vol.29,No.5,200821.韩 永，赵凤生，张 鉴，“卫星_地面观测数据融合方法研究”，量子电子学报，Vol.20, No.2, Apr., 200322.张 鉴，何晓雄，赵凤生，“利用大气-海洋系统辐射传输模拟水色遥感信息量的变化特性”，量子电子学报，Vol.20, No.5, Oct., 200323.冯 明（研究生），张 鉴，黄庆安，“ICP刻蚀中等离子体分布的模拟”，电子器件，Vol.28, No.3, 200524.胡智文，张 鉴，“壳聚糖胃滞留-漂浮微球体外释药模型研究”，计算机工程与应用 45 (33): 213-215 200925.张 鉴，黄庆安，“ICP刻蚀技术与模型”，微纳电子技术，Vol.42, No.6, 200526.徐栋梁（研究生），张鉴*，微机械加工工艺的三维仿真模型及算法，电子科技，Vol.23,No.8,201027.吕 明，张 鉴*，“SU-8胶光刻的相关效应及其优化方法”，四川师范大学学报（自然科学版）， 33, 2010: 356-359参加国际会议1. Jian Zhang, et al, Oral 。
5.哪位有"可见光通信及其关键技术"相关的论文或资料啊
文献来源munication; white LED; field of view; inter symbol interference； 【摘要】 可见光通信系统采用白光发光二极管（LED）作为光源，因而系统具有通信与照明的双重作用，极大地节约了能源。
描述了可见光通信的结构与特点，对可见光通信的一些关键技术做了简单的研究，并介绍了可见光通信的发展动态。 【英文摘要】 The visible light communication(VLC) is a kind of optical wireless communication that uses the white LEDs.In VLC system,white LEDs are used not only as the illuminator in the rooms,but also as the source of the communication system.The configuration,characteristics and key techniques of visible light communication are described.The devolopment status in the field of VLC is introduced. 【基金】 陕西省“火矩计划”项目（2002HK52）；； 陕西省教育厅科技资助项目（04JK247） 2 光通信 可见与红外、紫外通信 中国光学与应用光学文摘 2006/013 3 光通信 可见与红外、紫外通信 中国光学与应用光学文摘 2006/03 4 光通信 可见与红外、紫外通信 中国光学与应用光学文摘 2006/05 5 光通信 可见与红外、紫外通信 中国光学与应用光学文摘 2005/06 6 光通信 可见与红外、紫外通信 中国光学与应用光学文摘 2005/04。
6.求一篇LED节能灯方面的英文论文
So according to the Environmental Protection Agency, swapping your old incandescent bulbs for the latest eco-friendly technology can reduce energy use by 50 to 75%. And with Congress getting close to passing an energy bill to phase out that 125-year-old incandescent, it might be time to get, well, enlightened on the latest energy-saving options. There are so many different kinds of light bulbs. You have light emitting diodes - LEDs, CFLs - compact fluorescent light bulbs, halogens. It's really confusing. What should I be buying? You can either buy a very inefficient bulb very inexpensively, your grandma's bulb, the incandescent bulb. Or you can spend more money up front and pay far less in the other use for they last a lot longer for either compact fluorescent or you can find one in LED bulb. Right now compact fluorescents cost a fair amount of money to buy, but that money is more than paid off in the lifetime of the bulb. But in the compact fluorescent are some things which you don't want to get into the environment. So you got to recycle those. It's Important to know that CFLs do contain about five milligrams of mercury. That's a tiny amount. It's about the same as a pen prick. But mercury is a toxic chemical, so you want to take caution especially should your CFL break or burn out. The Environmental Protection Agency has a comprehensive guide to proper CFL disposal. And another new option you might want to consider are LED or light emitting diode bulbs. Now these bulbs are harder to find and they're significantly more expensive, about 30 to 40 dollars each. But they also last a lifetime. They are also mercury-free, so you don't have to worry about toxicity should they break. And whatever bulbs you choose, be sure to consider additional steps to limit your electricity usage. For example, dimmable lights which its motion sensors are great way to curb energy use. So for more information on efficient lighting applications and other ways to save energy, check out the CNN Money.COM/REALESTATE. Glossary。
7.何建军的发表论文
RESEARH HIGHLIGHTS - 16x100GHz Digitally Wavelength Switchable V-Coupled-Cavity Laser with 40dB SMSR, Jialiang Jin, Lei Wang, Tingting Yu, Yin Wang, and Jian-Jun He, Postdeadline Paper, CLEO-PR, Sydney, Australia, Aug. 27-Sept.1, 2011.- The Lord of the Rings of optical biosensors, Jian-Jun He, Lei Jin, and Mingyu Li, SPIE Newsroom, September 2011, DOI: 10.1117/2.1201108.003763.- Integrated Photonics Research in China, Andrew W. Poon, Linjie Zhou, Jianping Chen, Yong-Zhen Huang, Jinzhong Yu, Jian-Jun He and Hon K. Tsang, Optics and Photonics News, pp. 23-29, September 2011.- “Compact AWGs eye access applications”, Fiber Systems/Lightwave Europe, R&D News, p. 7, March 2006. REPRESENTATIVE JOURNAL PUBLICATIONS2013- X. Jiang, J. Ye, J. Zou, M. Li, and J.-J. He, “Cascaded silicon-on-insulator double-ring sensors operating in high-sensitivity transverse-magnetic mode”, Optics Letters, 2013.- Jun Zou, Xianxin Jiang, Xiang Xia, Tingting Lang, and Jian-Jun He,Ultra-Compact Birefringence-Compensated Arrayed Waveguide Grating Triplexer Based on Silicon-on-Insulator, J. Lightwave Technol., 2013.- Xiao Ma, Mingyu Li and Jian-Jun He. “CMOS-Compatible Integrated Spectrometer Based on Echelle Diffraction Grating and MSM Photodetector Array”, IEEE Photonics Journal, 2013.- Mohammad Kaleem, Xin Zhang, Yuan Zhuang, Jian-Jun He, Neng Liu and Jan J. Dubowski, UV laser induced selective-area bandgap engineering for fabrication of InGaAsP/InP laser devices, Optics & Laser Technology Journal, 2013.- Jinyan Song, Sophie Bouchoule, Gilles Patriarche, E. Galopin, Alejandro Giacomotti, E. Cambril, Qingli Kou, D. Troadec, Jian-Jun He, and Jean-Christophe Harmand, “Improvement of the oxidation interface in an AlGaAs/AlxOy waveguide structure by using a GaAs/AlAs superlattice”, Phys. Status Solidi A, (2013) / DOI 10.1002/pssa.201228770.- Y. Hu, M. Li, J.-J. He, R.R. LaPierre, Current matching and efficiency optimization in a two-junction nanowire-on-silicon solar cell, Nanotechnology 24 ,065402 (2013).- X. Ma, M. Li and J.-J. He, “Echelle Diffraction Grating Based High-resolution Spectrometer-on-a-chip on SiON Waveguides Platform”, Chinese Opt. Lett. 11(3), 032501(2013). 2012 - “Experimental Demonstration of Birefringence Compensation Using Angled Star Couplers in Silica-Based Arrayed Waveguide Grating”, Xiang Xia, Jun Zou, Tingting Lang, and Jian-Jun He, IEEE Photonics Journal, Vol. 4, No. 6, pp. 2236-2242 (2012).- Optical characteristics of GaAs nanowire solar cells, Y. Hu, R. R. LaPierre, M. Li, K. Chen, and J.-J. He,J. Appl. Phys. 112, 104311 (2012).- Single-Mode and Wavelength Tunable Lasers Based On Deep-Submicron Slots Fabricated By Standard UV-Lithography, Tingting Yu, Li Zou, Lei Wang, Jian-Jun He, Optics Express 20, pp. 16291-16299 (2012).- Intensity interrogated sensor based on cascaded Fabry-Perot laser and micro-ring resonator, Jinyan Song, Lei Wang, Lei Jin, Xiang Xia, Qingli Kou, Sophie Bouchoule, and Jian-Jun He, J. Lightwave Technol. 30, pp. 2901-2906, 2012. - Digitally Wavelength Switching by Thermal and Carrier Injection Effects in V-Coupled Cavity Semiconductor Laser, Jialiang Jin, Lei Wang, J.-J. He, Chinese Opt. Lett. 10(10), 102501(2012). - Narrow Linewidth Single-Mode Slotted Fabry-Perot Laser Using Deep Etched Trenches, Yin Wang, Lei Wang, Youguang Yang, Sen Zhang and Jian-Jun He, IEEE Photon. Technol. Lett. 24, pp. 1233-1235 (2012).- Wavelength Switchable Semiconductor Laser Based on Half-wave Coupled Fabry-Perot and Rectangular Ring Resonators, Lin Wu, Yin Wang, Tingting Yu, Lei Wang, and Jian-Jun He, IEEE Photon. Technol. Lett. 24(12), pp. 991-993, 2012.- “Optical Sensor Based on Vernier-Cascade of a Ring Resonator and an Echelle Diffraction Grating”, Li Qin,Lei Wang,Mingyu Li,and Jian-Jun He, IEEE Photon. Technol. Lett. 24(11), pp. 954-956, 2012.- Fabrication of GaAs Nanowires by Colloidal Lithography and Dry Etching, Ke Chen, Jian-Jun He, Mingyu Li, and Ray LaPierre, Chinese Physics Letters, Vol. 29, No. 3 , 036105, 2012.- “Analysis of wavelength and intensity interrogation methods in cascaded double-ring sensors”, L. Jin, M. Li, and J.-J. He, J. Lightwave Technol., vol. 30, no. 12, pp. 1994-2002, 2012.- “Travelling wave analysis on high-speed performance of Q-modulated distributed feedback laser”, J. Zhi, H. Zhu, D. Liu, L. Wang, and J.-J. He, Opt. Express, Vol. 20, No. 3, pp. 2277-2289, 2012.2011 and Earlier - “Widely wavelength switchable V-。
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