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11.
The discretization of real values is always one of the key problems to be solved in the domain of machine learning for its great contribution to speeding up the followed learning algorithms, cutting down the real demand of algorithms on running space and time, and improving the clustering capability of the ultimate learning results. The basic characteristics and framework of discretization approaches based on rough set model are analyzed at first, then the different measurements of the importance of candidate cuts are discussed and researched. Two new heuristic algorithms are put forward to finally select the useful cuts from a candidate set. The selected cuts of the two algorithms will adequately maintain the discernible relation of information systems for their full considering the specialty of rough set, which perfectly embodies the advantages of this theory. Moreover, excellent discretization results may be expected through these heuristic algorithms. 相似文献
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为探究切花向日葵生产碳足迹和经济效益,通过调研切花向日葵生产企业,利用生命周期评价法评估露地,拱棚和日光温室3种不同生长条件下切花向日葵碳排放,核算生产成本和效益,结果表明:露地切花向日葵生产碳足迹为2174.46kg/hm2,生产成本51994元/ hm2,收入178608元/ hm2;拱棚向日葵生产碳足迹为2041.13kg/ hm2,生产成本59443元/ hm2,收入175973元/ hm2;日光温室向日葵生产碳足迹为2038.92kg/ hm2,生产成本58465元/ hm2,收入179544元/ hm2。3种不同生长条件下切花向日葵生产的主要成本均来自人工,种子,地租和肥料,碳排放最主要的来源均为厩肥和氮肥。在未来切花向日葵生产中,可通过优化生产技术提高肥料利用率,研发专用机械降低劳动力投入,增加轮作等途径来实现减排增收的目的。 相似文献
13.
Magda Marin Luis A. Valdez-Aguilar Ana Maria Castillo-Gonzalez Joel Pineda-Pineda Juan J. Galván Luna 《Journal of plant nutrition》2013,36(1):12-26
Nutrient solution composition plays an important role in root uptake rate due to interactions among nutrients and internal regulation. Studies to determine the optimum nutrient solution concentration are focused on individual ions, ignoring the adaptation mechanisms triggered by plants when growing in a varying external nutrient concentration. The objective of the present study was to determine the response in growth and tissue ion concentration of lilium cv. ‘Navona’ to nutrient mixtures of varying proportions of nitrogen (N), potassium (K+), and calcium (Ca2+) in solution using mixture experiments methodology in order to determine the optimum concentration. Bulbs of lilium were transplanted in plastic crates and drip-irrigated with the treatment solutions, which consisted of a mixture of N, K+, and Ca2+ whose total concentration was 340 mg L?1 and minimum concentrations of each ion was 34 mg L?1. Chlorophyll concentration (SPAD), shoot fresh weight (FW), leaf FW, and leaf area were measured 60 days after transplanting and ion analysis was performed on shoot tissues from selected treatments. Lilium exhibited a moderate demand for N and K+ (136–170 mg L?1 N and 116–136 mg L?1 K+) and a very low demand for Ca2+ (34–88 mg · L?1). This low demand may be due to the remobilization of the nutrients stored in the bulbs. Integrating the predictions of the models estimated to produce >90% of maximum growth, the optimum nutrient solution should contain Ca2+ at a concentration between 34 and 126 mg · L?1, K+ between 119 and 211 mg · L?1, and N between 92 mg · L?1 and 211 mg · L?1. Increasing external N concentration affected internal N concentration but not internal K+ or Ca2+ concentrations, despite that the increase in external N was associated with a decrease in external K+ and Ca2+. Similar trends were observed for external K+ and Ca2+ concentration. In conclusion, lilium was able to maintain a relatively constant K+ and Ca2+ concentration regardless of the lower concentration in the nutrient solution when N was increased (similar response was observed for K+ and Ca2+) and it has a low Ca2+ demand and moderate N and K+ supply. 相似文献
14.
采用在线热裂解—气相色谱/质谱联用技术(Py-GC/MS),模拟卷烟燃吸状态,研究了苦水玫瑰油在无氧条件下的热裂解行为,为其在卷烟中应用提供了理论依据。将苦水玫瑰油样品分别在不同温度(300,600,900℃)下进行热裂解,将热解产物直接引入气相色谱—质谱仪进行定性和半定量分析。结果表明,苦水玫瑰油裂解产物中主要包括醇类、酯类、萜烯类、脂肪烃类和醚类等致香成分,其中含量较高的物质包括香茅醇、香叶醇和芳樟醇等有具有浓郁而持久的玫瑰香气的化合物,这些物质有助于增进卷烟甜香、玫瑰香,使烟气柔和。 相似文献
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采用UG软件虚拟设计了玉米收获机中立轴式甩刀三维实体。并应用机械系统动力学分析软件ADAMS构建了三维运动仿真模型,实现了在ADAMS环境下甩刀运动仿真分析和甩刀切割玉米茎秆仿真分析。仿真结果表明,甩刀运动初期刀片运动不稳定,切割玉米茎秆时切割力大小真实可靠。 相似文献
18.
壳聚糖保鲜液对唐菖蒲切花保鲜的影响 总被引:9,自引:0,他引:9
试验采用0.25‰,0.5‰,0.75‰,1‰,1.25‰的壳聚糖保鲜液处理唐菖蒲切花,观察切花寿命和开花率,旨在探索壳聚糖保鲜液处理切花的效果。试验结果表明,1‰壳聚糖保鲜液处理后的鲜切花,寿命最长,开花率最高。 相似文献
19.
Bayzid Yousefi Seyed Reza Tabaei-Aghdaei Farrokh Darvish Mohammad Hassan Assareh 《Scientia Horticulturae》2009
The flower yield stability of Damask rose as an important medicinal and aromatic plant at different environments has not been well documented. In order to evaluate flower yield and stability, 35 landraces of Damask rose were studied at 8 locations in Iran during 2007–2008. Analysis of variance revealed significant differences (p ≤ 0.01) among landraces (G), environments (E), locations (L) and for landrace × environment (GE) and landrace × location (GL) interactions. Both GE and GL interactions were mainly crossover, a large portion of which was accounted for by non-linear (unpredictable) component. The landraces of IS9, YZ2, WA1, IS7 and IS1 with 3120.63, 2941.63, 2894.62, 2769.15 and 2716.92 kg/ha respectively produced the highest flower yield among studied landraces. Kerman with average flower yield of 3635.46 kg/ha produced the highest yield among studied locations. According to the results, most of landraces that originated from temperate, warm temperate and arid regions produced higher flower yield than those from cool, cool temperate, semi-arid and humid regions. The landraces of YZ2, IS5, IS8, IS4, KZ1, AR1, IS3 and BA1 were stable and YZ2, IS5, IS8, IS4, KZ1, AR1 IS6, IS3, BA1, IS10 and YZ1 were adaptable landraces for flower yield according to Eberhart and Russell (1966) model. The presence of some high flower yield and stable landraces such as YZ2 and IS5 suggests that a genotype can demonstrate high flower yield and stability for yield simultaneously. Thus, simultaneous selection for flower yield and stability using nonparametric methods could be possible. In addition, taking into consideration flower yield and stability potential, the landraces of YZ2, IS5, IS8, IS4 and KZ1 as general stable, adaptable, and high flower yield are recommended. Furthermore, the landraces of IS9 and WA1 as high flower yield and specific adaptable landraces can be recommended for temperate and arid areas and the landraces of IS7 and IS1 for semitemperate and cool areas. 相似文献
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