A novel high-order weighted fuzzy time series model and its application in nonlinear time series prediction

Conventional time series forecast models can hardly develop the inherent rules of complex non-linear dynamic systems because the strict assumptions they need cannot always be met in reality, whereas fuzzy time series (FTS) techniques can be used even the records of times series have uncertainty and instability since they do not need strict assumptions. In previous study of FTS, the process of aggregating the past observations and assigning proper weights of fuzzy logical relationship groups are ignored, which may lead to poor forecasting accuracy since they are important aspects in time series prediction and analysis where determination of future trends depends only on past observations. In this paper, a novel high-order FTS model is constructed to make time series forecasting. Specifically, by applying the harmony search intelligence algorithm, the optimal lengths of intervals are tuned. Moreover, regularly increasing monotonic quantifiers are employed on fuzzy sets to obtain the weights of ordered weighted aggregation. Simultaneously, the weights of right-hand side of fuzzy logical relationship groups are explored to compensate the presence of bias in the prediction. In the part of empirical analysis, the developed model was applied to predict three well-known time series: numbers of enrollment of Alabama University, TAIEX and electricity load demand of New South Wales and the results obtained were compared with several counterparts, including some old and recently developed models. Experimental results demonstrate that the developed model cannot only achieve higher accuracy of prediction, but also capture the fuzzy features and characters.     

Effects of gamma irradiation on trans fatty acid composition in ground beef

The present study was conducted to evaluate the combined effects of irradiation (0, 1, 3, 5 and 7 kGy) of ground beef on fatty and trans fatty acids. Irradiation of ground beef was performed by gamma rays from a ⁶⁰Co source. Irradiated ground beef samples had higher concentrations of total trans fatty acids than the control samples. Irradiated ground beef samples with 7 kGy had the highest total trans fatty acids, total monounsaturated and total unsaturated fatty acids than the other samples. In this study results showed an increase in trans fatty acids related to the increase on irradiation dose in ground beef and irradiation dose changed fatty acids composition especially trans fatty acids in ground beef.     

Deep-red emission of Mn4+ and Cr3+ in (Li1−xAx)2MgTiO4 (A=Na and K) phosphor: Potential application as W-LED and compact spectrometer

Mn⁴⁺ doped and Mn⁴⁺/Cr³⁺ co-doped alkali metal titanate phosphors have been prepared by solid state reaction method. A part of Li⁺ ions in the Li₂MgTiO₄: Mn⁴⁺ are substituted with Na⁺ and K⁺ ions and consequently the intensity of Mn⁴⁺ emission at 678 nm is enhanced by 1.7 and 2.5 times, respectively. In the Mn⁴⁺/Cr³⁺ co-doped (Li_0.95K_0.05)₂MgTi_0.999O₄, both emission of Cr³⁺at 726 nm and emission of Mn⁴⁺ at 678 nm of Mn⁴⁺ are observed. It is interesting to find that the intensity ratio of 726–678 nm emissions in the Mn⁴⁺/Cr³⁺ phosphor continually increases with excitation wavelength increasing from 290 nm to 455 nm, which means that the intensity ratio in turn can be used to identify the excitation light wavelength. This refers a possible approach to design novel compact light-wavelength detector or spectrometer based on the phosphor. The mechanism of Na⁺ or K⁺ substitution induced luminescence enhancement in the Mn⁴⁺ phosphor and the competition between the Cr³⁺ and Mn⁴⁺ emissions in the Mn⁴⁺/Cr³⁺ co-doped has been discussed.     

Comparative study of the Mn4+ 2E → 4A2 luminescence in isostructural RE2Sn2O7:Mn4+ pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+)

Red emitting Mn⁴⁺-doped crystalline materials have potential for application in light emitting devices and therefore it is important to understand how the optical properties of Mn⁴⁺ are influenced by the host lattice the Mn⁴⁺ ions are situated in. In this work we investigate the effect of the host cations in the second coordination sphere on the Mn⁴⁺ emission by studying the luminescence of Mn⁴⁺ ions doped into three isostructural rare earth (RE) stannate RE₂Sn₂O₇ pyrochlores (RE³⁺ = Y³⁺, Lu³⁺ or Gd³⁺). It is found that the energies of the Mn^{4+ 4}T₁ and ⁴T₂ states significantly increase with decreasing Mn⁴⁺-O^2- distance, whereas the energy of the ²E level shows a small shift to higher energies from RE³⁺ = Gd³⁺ to Lu³⁺ to Y³⁺. The observed trend for the ²E level energy is not related to the size of the RE³⁺ ion and is not in line with theoretical calculations reported previously. Low temperature emission spectra of the RE₂Sn₂O₇:Mn⁴⁺ phosphors reveal that only asymmetrical vibronic modes couple to the ²E → ⁴A₂ transition and furthermore show there is significant and unexpected local disorder for Mn⁴⁺ in Gd₂Sn₂O₇ that is not observed for Mn⁴⁺ in the other hosts. Photoluminescence decay measurements demonstrate that the luminescence of RE₂Sn₂O₇:Mn⁴⁺ is strongly quenched below room temperature which is assigned to non-radiative relaxation via a low-lying O²⁻ → Mn⁴⁺ charge-transfer state.     

基于多特征的P2P直播流识别方法

基于P2P的直播应用是当前发展最为迅速的因特网应用之一,实时识别P2P直播流是管理网络P2P流媒体流量和理解网络行为的关键一步.针对当前P2P流媒体直播流的识别方法较少,识别效果一般,文章分析了P2P直播流的行为特征,提出了基于节点连接度的识别方法和基于BM信息比的识别方法,并结合两个流量特征采用联合特征进行P2P直播识别.实验表明该方法识别整体准确率较高,可以实现P2P直播的在线识别.     

Quasicrystals,crystals and multiply twinned particles: A unified growth model

A recursive (R) quasicrystal growth model which unifies existing theories, including multiple twinning is presented. The model generates infinite, space-filling structures reproducing the structure of observed quasicrystals, crystals, multiply twinned particles and predicts the possible existence of incommensurate structures not observed yet. The R model is generalization of the crystal case where the structure is generated by periodic translations of the unit cell into any of its points. For quasicrystals, the unit cell is replaced by a star vector with icosahedral or decagonal symmetry and displacements are restricted to points belonging to the Coincidence Site (Quasi) Lattice.