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A simple and accurate method based on degenerate four-wave mixing (FWM) to evaluate optical fiber dispersion and nonlinearity is presented. We investigated the continuous wave degenerate FWM characteristics of two photonic crystal fibers (PCFs) and a SMF28 fiber. Simply by measuring and analyzing the continuous wave degenerate FWM conversion efficiency as a function of the wavelength difference between pump and signal waves, fitting between experimental data and analytical FWM conversion efficiency expression is carried out to determine the dispersion, dispersion slope and nonlinear coefficient of the fiber. The fiber parameters simultaneously obtained from a single set of FWM measurement for Single Mode Fiber 28 (SMF28) are found to be agreement with the manufacturer specifications for this fiber, thus validating the PCF results and, more generally, the acceptable accuracy of the simple method proposed here.

This study seeks a distinctive and efficient machine learning system for the prediction of Cotton Production using weather parameters and climate change impact on cotton production. Cotton is a crucial harvest for Pakistan referred to as “white gold”. Cotton is taken into account lifeline of Pakistan's economy. Pakistan is the fifth largest cotton producer. Cotton and textile exporters are the rear bone of Pakistan's economy. Being a cotton-based economy Pakistan aims to extend its share in the billion-dollar value-added global textile market. But in the process of cotton growth affected by meteorological conditions, extreme weather can cause cotton production, based on this kind of situation, machine learning technology to deal with meteorological data analysis, realize the accurate prediction of cotton production, on the influence of the main meteorological factors on cotton yield and diseases, the selection suitable for cotton varieties and resist meteorological disaster is of great significance. The study analyses the impact of weather parameters on the productivity of cotton in Pakistan using the district level disintegrated data of yield, area, and climate variables (temperature, cloud cover, rainfall, and wind) from 2005-to 2020, also uses the Production of cotton from 2005-2020. These Sixteen years moving averages for each month, climate variables are used. The production function approach is used to analyze the relationship between crop yield and weather parameters up and down each month. Cotton has a great dependence on environmental factors during its growth, especially climate change. The occurrence of cotton pests and diseases has always been an important factor affecting total cotton production. Pests and diseases are also caused by environmental factors. Apply a Machine learning algorithm to analyze the pests and diseases of cotton because of environmental factors. Model construction and analysis of meteorological factors the Decision Tree, Random Forest, Linear Regression, and XGB algorithm using ensemble technique were established for cotton yield prediction in Pakistan and the performance of each model was compared. The comparison results show that the prediction results of the prediction model using the optimization algorithm are significantly improved, among which the XGB model using ensemble techniquehas the best performance, and the root mean square error (RMSE), and mean square error (MSE) of the prediction results are 0.07and 0.27 respectively. The relationship between main meteorological factors and cotton yield was analyzed by XGB algorithm. The results showed that temperature, cloud cover, rainfall, and wind were the most important factors affecting cotton yield in Pakistan from each growth stage of cotton, the boll stage is the most susceptible to meteorological factor, and the bud stage is the second the geographical location, climatic characteristics and meteorological disasters that resulted in cotton production. So, because of these factors indication on time action can increase the production and overcome on the cotton declined production. In the future there are many improvement ways one thing we can do that is daily base weather parameters use for prediction and diseases related to weather elements. Increase of other weather parameters will be more affective in future.

Using an ytterbium-doped fiber with a 50 μm core and 0.028 NA, a pulse energy of 4.8 mJ was achieved directly from a single-mode Q-switched fiber laser. The repetition rate was 10 kHz and the average power was 48.4 W. The slope efficiencies with regard to the absorbed and launched pump power were ∼74% and ∼59% respectively. The pulse width decreased with increasing pump power. The 4.8 mJ pulse had a FWHM width of ∼300 ns. A shorter pulse of ∼200 ns FWHM was also achieved at 2.06 mJ in another configuration. The M2 was below 1.3 at all pulse energies. This work demonstrates record pulse energy directly from a single-mode Q-switched fiber laser and the feasibility of operating such a laser with high efficiencies.

Sparse code multiple access (SCMA) is one of the most intensively investigated non-orthogonal multiple access (NOMA) techniques for the fifth generation communication (5G) system. In this paper, a new multi-stage optimization approach for codebook design is proposed for the uplink SCMA system. The proposed schemes includes two parts: i) multi-dimensional mother constellation design ii) mapping matrix design. Firstly, the multi-dimensional complex mother constellation design is implemented by a series of two-dimensional real constellations which can be obtained by the lattice theory and the symbol switch algorithm (SSA). The Secondly, we construct user-specific mapping matrix by optimizing the phase rotation of the user constellation to effectively reduce the interference between the multi-user codewords superimposed on every single time-domain resource elements (REs). Finally, the multi-user codebooks are generated by combining the multi-dimensional mother constellation and the user-specific mapping matrix. The simulation results demonstrate that the proposed codebooks can greatly decrease bit error rate (BER) value compared to the existing codebooks under different channels, different codebook sizes and different overloading ratios, and the performance is also improved for the large-scale SCMA codebook. More importantly, in order to verify the proposed codebook applicability, two different message passing algorithm (MPA) are used to simulate the SCMA system with different codebook sizes, both of which obtain faster convergence speed and better BER performance than other existing codebooks.

This paper investigates the energy-efficient communications and user capacity in the cognitive multiple input multiple output (MIMO) symmetric system of underlay mode. The advantage of the improved energy efficiency provided by the orthogonal slot allocation for time division multiple access (TDMA) has a side effect of restricting the number of users accessing the system. To tackle the above problem, this paper proposes a nonorthogonal time resource allocation method with sparse code multiple access (SCMA), which allows one to convert the orthogonal slot units of TDMA into non-orthogonal shared slot units for multiple secondary users (SUs). The method of adding virtual users is adopted, wherein each SU is treated as multiple SUs who occupy a shared unit, to facilitate the packet access. Finally, the greedy algorithm is applied to optimize the time slot allocation of unoccupied shared slot units. The simulation results show that SCMA-based nonorthogonal slot allocation can reduce not only the energy consumption by nearly 40%, but also the average power interference from SUs to primary users by nearly 2 dB if their number is relatively high. Moreover, in the case of satisfying the rate requirement of the users, the system user capacity increased by more than 50%.

Background Ankle arthrodesis is considered to be the gold standard for the treatment of end-stage ankle diseases. At present, the commonly used methods of ankle arthrodesis include open ankle arthrodesis, arthroscopic ankle arthrodesis and mini-open ankle arthrodesis. The authors analyze and compare the clinical efficacy and related complications of arthroscopic ankle arthrodesis and mini-open ankle arthrodesis in the treatment of end-stage ankle disease. Methods From January 2007 to June 2018, 56 patents with end-stage ankle joint pathology were treated with arthroscopic ankle arthrodesis and mini-open ankle arthrodesis. There were 30 cases in arthroscopy group, including 19 males and 11 females with an average age of 49.6 years old (ranged, 32 to 71); while 26 cases in mini-open group, including 18 males and 8 females with an average age of 48.3 years old (ranged, 43 to 65). The operative time was calculated with use of computerized operative and anesthetic records. The pain visual analogue score (VAS), American Orthopedic Foot ༆ Ankle Society ankle and hind foot score (AOFAS), fusion rate, complications rate, length of hospital stay, operation time, and tourniquet time were compared between the two groups of patients. Results 51 patients were followed up for 15–35 months (mean, 22.5 ± 1.5) months. The bony fusion was achieved in all patients. The average time to fusion was 12.4 weeks (range, 10–16 weeks). The VAS score 3 days post-operation was (6.37 ± 0.69) points in the arthroscopy group and (7.61 ± 1.05) points in the mini-open group, there was significant difference between the two groups (P 0.05). The AOFAS score was (85.32 ± 2.96) points in the arthroscopy group and (86.72 ± 3.05) points in the mini-open group, and there was no significant difference between the two groups (P > 0.05). Arthroscopic ankle fusion was associated with a shorter tourniquet time and shorter length of hospital stay compared to mini-open ankle fusion (P 0.05). Wounds healing was satisfying during the follow-up in the arthroscopy group. But the wounds healing was delayed in two patients of the small incision group. All patients were satisfied with the surgery. Conclusion Arthroscopic ankle arthrodesis and mini-open ankle arthrodesis have satisfactory curative effect and fusion rate. Arthroscopic assisted ankle arthrodesis has more advantages, including small incision, less injury, and low morbidity.

Polar coding and sparse code multiple access (SCMA) technique are excellent candidates for 5G, and have a promising prospect in optical communication, the joint design of polar coded sparse code multiple access (PC-SCMA) system is important to enhance the overall system performance. In this paper, a serial joint iterative detection and decoding scheme is proposed by passing message between serial max-log message passing algorithm and soft cancellation (SCAN) algorithm, the strategy can accelerate the algorithm convergence speed by reducing the number of required iterations, decrease the computational complexity and achieve ideal bit error rate (BER) performance. In order to further improve the BER performance, a cyclic redundancy check (CRC) is added in the joint iterative process as an early stopping criterion to avoid decoding divergence caused by a low signal to noise ratio (SNR). Simulation results demonstrate that the addition of a termination mechanism can obtain an excellent performance gain compares with the conventional JIDD algorithm.

To date, the role of Dickkopf 3 (Dkk3) on the pathogenesis of familial dilated cardiomyopathy (FDCM), and whether and how Dkk3 interferes with Wnt signaling in heart tissues remains unknown. Here, we demonstrate that strong Dkk3 expression was markedly downregulated in adult hearts from WT mice, and Dkk3 expression was upregulated suddenly in hearts from DCM mouse models. Using Dkk3 transgenic and knockout mice, as well as cTnT(R141W) transgenic mice, which manifests progressive chamber dilation and contractile dysfunction and has pathologic phenotypes similar to human DCM patients, we determined that transgenic expression of Dkk3 increased survival rate, improved cardiac morphology breakage and dysfunction, and ameliorated cardiac pathological changes in the cTnT(R141W) mice. In contrast, Dkk3 knockout reduced the survival rate and aggravated the pathological phenotypes of the cTnT(R141W) mice. The protective effects of Dkk3 appeared clearly at 3 months of age, peaked at 6 months of age, and decreased at 10 months of age in the cTnT(R141W) mice. Furthermore, we determined that Dkk3 upregulated Dvl1 (Dishevelled 1) and key proteins of the canonical Wnt pathway (cytoplasmic and nuclear β-catenin, c-Myc, and Axin2) and downregulated key proteins of the noncanonical Wnt pathway (c-Jun N-terminal kinase (JNK), Ca(2+)/calmodulin-dependent protein kinase II (CAMKII), and histone deacetylase 4 (HDAC4)). In contrast, Dkk3 knockout reversed these changes in the cTnT(R141W) mice. In summary, Dkk3 could prevent FDCM development in mice, especially in the compensatory stage, and probably through activation of the canonical and inhibition of the noncanonical Wnt pathway, which suggested that Dkk3 could serve as a therapeutic target for the treatment of cardiomyopathy and heart failure.

Background Calponin1 (CNN1) is involved in the regulation of smooth muscle contraction in physiological situation and it also expresses abnormally in a variety of pathological situations. We found that the expression of CNN1 decreased significantly in the heart tissue of a cTnT R141W transgenic dilated cardiomyopathy (DCM) mouse model and an adriamycin (ADR)-induced DCM mouse model, suggesting that CNN1 is involved in the pathogenesis of DCM. However, the role of CNN1 on cardiac function, especially on pathogenesis of DCM, has not been clarified. In this study, we tested whether rescued expression of CNN1 could prevent the development of DCM and investigated its possible mechanisms. Methods and results The DCM phenotypes were significantly improved with the transgenic expression of CNN1 in the cTnT R141W ×CNN1 double transgenic (DTG) mice, which was demonstrated by the survival, cardiac geometry and function analyses, as well as microstructural and ultrastructural observations based on echocardiography and histology examination. The expression of CNN1 could also resist the cardiac geometry breakage and dysfunction in the ADR-induced DCM mice model. Meanwhile, the epsilon isoform of protein kinase C (ePKC) activator and inhibitor could reverse the activation of ePKC/ERK/mTOR pathway and DCM phenotypes in the cTnT R141W and cTnT R141W ×CNN1 double transgenic (DTG) mice. Conclusions ePKC/ERK/mTOR pathway activation induced by the rescued expression of CNN1 contributed to the improvement of cardiac dysfunction and pathological changes observed in the DTG mice. CNN1 could be a therapeutic target to prevent the development of DCM and heart failure (HF).

Ginsenoside-Rb1 (Rb1) is known to be partially associated with the inhibition of heparin-binding epidermal growth factor-like growth factor (HB-EGF). Tetramethylpyrazine phosphate (TMPP) inhibits the activation of the calcium/calmodulin/calmodulin-dependent protein kinase (Ca²⁺/CaM/CaMKII) pathway. The α-myosin heavy chain cTnT(R141W) transgenic mouse was previously reported as a model for dilated cardiomyopathy (DCM), and it was used to test the effects of combinations of Rb1 and TMPP in reversing the progression of DCM and the potential mechanism. Survival, echocardiography, histologic features assessed the effectiveness of Rb1 and TMPP treatments. Western blot and reverse transcription polymerase chain reactions were used to determine expression levels of certain genes. This study clearly demonstrated that treatment with a combination of Rb1 and TMPP could inhibit the expression of HB-EGF, calmodulin1 (Calm1), and calcium/calmodulin-dependent protein kinase II beta (Camk2b). Rb1 alone mainly reduced the expression of HB-EGF, and TMPP alone mainly reduced the expression of Calm1 and Camk2b. Treatment with Rb1 and TMPP had synergistic effects on the amelioration of chamber dilation, contractile dysfunction, interstitial fibrosis, and ultrastructural degeneration in cTnT(R141W) mice when compared with the results of treatment with Rb1 or TMPP alone, and those were probably due to the inhibition of both HB-EGF and the Ca²⁺/CaM/CaMKII pathway.

Online handwriting recognition is a very important part in the field of pattern recognition. Up to now there are few reports about the online Uyghur word handwriting recognition. This paper proposes an effective method based on HMM to recognize handwritten Uyghur word. This method introduces a feature extraction approach and presents a language model, resulting in a higher accuracy.

We investigated the continuous wave degenerated FWM characteristic of SMF28 and PCF and measured the efficiency of the newly created frequency with respect to wavelength difference between pump and signal waves, and the FWM conversion polarization dependence on pump and signal light. The dispersion, dispersion slope and nonlinear coefficient of the fiber were determined.

By using degenerated four wave mixing (FWM) method and counting the efficiency of the newly created frequency, we easily obtained dispersion, dispersion slope and nonlinear coefficients by fitting the experimental data with several well-known functions.

Under the high energy irradiation, the charges (even little) of molecules of polymer can cause the physical and chemical characteristics evident changes of polymer. The physics and chemical mechanisms which are responsible for radiation induced loss was analyzed. The radiation damage of polymethylmethacrylate (PMMA), Polystyrene PS and polycarbonate (PC) optical fiber under γ-ray irradiation was researched experimentally. The visible light transmission of the POF under different irradiation dose was measured. The results indicated that the radiation damage of three kinds of POF was wavelength-dependent. Under lower dose below 1KGy, the transmission rate decreased identical in the whole visible light range. When the irradiation dose exceeded 5KGy, the transmission rate reduced obviously, and the recovery indicated that the visible light transmission rate of the POF in the range of 400nm to 500nm comparing with 600nm to 800nm, decreased seriously under the irradiation dose exceeded 5kGy. The transmission rate of both PMMA and PC have an evident peak value at the range 550nm-650m, and that of PS has a wide band at the range 500-700nm. We also measured the recovery of three kinds of POF under different irradiation dose by measuring several times the POF after stopping irradiating.

The radiation damage and recovery of polymethylmethacrylate (PMMA), Polystyrene PS and polycarbonate (PC) optical fiber under γ-ray irradiation was researched experimentally. The visible light transmission rate of the POF under different irradiation dose was measured. The results indicated that the radiation damage of three kinds of POF was wavelength-dependent. Under lower dose below 1000Gy, the transmission rate decreased identical in the whole visible light range. When the irradiation dose exceeded 5000Gy, the transmission rate reduced obviously, and the transmission rate indicated that the visible light transmission rate of the POF at the range of 400nm to 500nm comparing 600nm to 800nm, decreased seriously. The transmission rate of both PMMA and PC have an evident peak value in the range 550nm-650m, and that of PS has wide peak value at the range 500-700nm. In addition, we measured the recovery of three kinds of POF five times following irradiation at the wavelength 632nm. Under low dose irradiation 100 Gy, the transmission rate reduced a little, and the irradiation damage can recover during a short time. When the irradiation dose reached 1000 Gy, the recovery process need longer time. When the irradiation dose exceeded 5000 Gy, the transmission rate reduced obviously, and the recovery process is slow and the irradiation damage can't recover completely, that indicated fiber suffered lasting damage.

The Step-index plastic optical fiber (SIPOF) bandwidth calculation model is given. The model includes not only the modal delay but also the attenuation and mode coupling effects. the numerical solution of the power flow equation in Fourier domain which is the main equation in this model is reported. This solution is based on Crank-Nicholson implicit difference method. The frequency response function and bandwidth of four kinds of SIPOFS with different Numerical aperture is researched. The frequency response function and bandwidth under selective excitation is numerically calculated. The results imply that the selective excitation of SIPOF increased effectively the fiber bandwidth. Calculated results are useful for practical application of plastic optical fiber.

Plastic optical fiber (POF) can be taken as short distance transmission system medium for replacing of coaxial cable because of its many excellent characteristics. The bandwidth characteristics of graded-index POF is strongly influenced by the differential mode attenuation (DMA). In this paper, a comprehensive bandwidth calculation model of POF is given. The analytical expression of DMA is fitted by eighth order polynomial from the experimental data, and is used for the calculation of fiber bandwidth. The frequency response function of graded-index plastic optical fiber(GIPOF) is calculated numerically under selective mode excitation condition, and the fiber bandwidth is studied. The calculated results indicated that the selective mode excitation could improve efficiently the fiber 3dB bandwidth. The influence of light source linewidth on fiber bandwidth is also investigated.

We performed some experimental studies on a new type cost-effective power coupling method for large-core POFs, and proposed a novel 1×4 plastic optical fiber (POF) power coupler which is different from fused-taper type and mixing rod POF couplers. Loss factors of this coupler are also analyzed theoretically. This coupler is based on thermal feature of POF, the two end of coupler is composed of fused-drawn tapered fiber and thermal-contracted tapered fiber, respectively, which is characterized as simple configuration and easily fabrication. The performance parameters of this coupler including excess loss, insertion loss, and channel cross-talk were measured. The loss and cross-talk can meet the practical requirement, and the channel uniformity is not desirable. The main issue is technical process. In our experiments, heated-drawing and contracting is controlled manually, the uniformity is deteriorated greatly, moreover, the distortion of POF during drawing and contracting is inevitable, as a result it leads to large bending loss. In addition, the termination of the taper and the alignment of optical path influences seriously on performances. Compared with mixing rod coupler, the coupler has advantages of simple structure, easy fabrication due to the absence of the mixing rod middle component. The further research on this coupler is to draw and contract fiber mechanically rather than manually, to enhance the uniformity, and to reduce loss further.

This paper presents a theoretical investigation on the mode coupling and mode coupling induced attenuation in step-index plastic optical fiber under different launching condition. We solved numerically power flow equation of multimode optical fiber by explicit finite difference methods. In our calculation, we adopted mode coupling coefficient measured in Garito’s experiments , and supposed power distribution of incident beam have Gaussin form with respect to angle between beam and optical core axis. Under different incident angle and same beam width, we calculated power distribution at fiber output end when optical fiber length is 1,5,15, 20, 50m respectively. In shorter transmission distance, mode coupling isn’t evident, output power distribution is similar to input ones. With increasing of fiber length, power diffused gradually from high order modes to low order modes, and mode coupling finished in about 20m, where equilibrium mode distribution is achieved. In addition, we calculated mode-coupling induced attenuation of different width and launching angle Gaussin beam, with enhancing of beam width and launching angle , attenuation increased .

Optical Burst Switching (OBS) functioning as an IP traffic aggregator at the edge of the Optical Transport Network is provided to enhance network flexibility and efficiency. This paper gives an overview of OBS node and the benefits it will bring about. It explains how an OBS node is modeled and simulated under different traffic conditions and gives the effect of Fiber Delay Line (FDL) in OBS node. Finally, the simulation results are presented and the performances of OBS node are evaluated.

In many magneto-optical materials, Faraday rotation is always accompanied by magnetic circular dichroism(MCD, that crystal represents different absorption coefficient of right and left circularly polarization light under magnetic field). In this paper, the theory of (MCD) of magneto-optical materials is introduced. The influence of MCD on polarization dependent optical isolator is analyzed through employing Jones vector and transmission matrix. The analytical formula about the relation of MCD and the insertion loss and isolation ratio of optical isolator is derived. The curve of insertion loss and isolation ratio with respect to MCD demonstrated that MCD degrades much isolation ratio comparing with insertion loss. It is evident from the curve the effect of MCD on isolation ration is general small, but in order to make increase in the isolation as high as possible and the insertion loss as small as possible, crystal with minimum MCD coefficient and maximum rotation coefficient should be chosen. The conclusion is significant to optical isolator optimization designing.