Improved Collaborative Filtering Recommendation Based on Classification and User Trust

When dealing with the ratings from users,traditional collaborative filtering algorithms do not consider the credibility of rating data,which affects the accuracy of similarity.To address this issue,the paper proposes an improved algorithm based on classification and user trust.It firstly classifies all the ratings by the categories of items.And then,for each category,it evaluates the trustworthy degree of each user on the category and imposes the degree on the ratings of the user.Finally,the algorithm explores the similarities between users,finds the nearest neighbors,and makes recommendations within each category.Simulations show that the improved algorithm outperforms the traditional collaborative filtering algorithms and enhances the accuracy of recommendation.

Ingestion of Brachionus plicatilis under different microalgae conditions

The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows： C. vulgaris 〉 P. helgolandicavar 〉 L galbana 〉 N. closterium. However, the filtering rates occurred in the following order： P. helgolandicavar 〉 N. closterium 〉 C. vulgaris 〉 L galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×10^6 cells mL^-1 for C. vulgaris and 1.5×10^6 cells mL^-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases： stationary phase 〉 exponential phase 〉 lag phase 〉 decline phase. Additionally, the filtering rates during the growth phases were： exponential phase 〉 lag phase 〉 stationary phase 〉 decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

Simulation and comprehensive assessment of single channel RZ-DPSK optical link by dispersion management with channel bit rate beyond 40 Gbits/s

This paper studied the influence of return to zero-differential phase-shift-keying （RZ-DPSK） data format on techniques of pre-, post- and pre/post combination dispersion compensation for faithful transmission of optical signal at 80 and 100 Gbits/s channel bit rate via simulation. The purpose of this study was to find out the dispersion compensation techniques for optimal transmis- sion with the interaction effects of self-phase modulation （SPM） and amplifier spontaneous emission （ASE） for RZ- DPSK encoded optical data. By the simulation method, it was found out that the RZ-DPSK data format can be allowed with a transmission distance of about 700 km of standard single mode fiber （SMF） at 100 Gbits/s, and it can be provided with farther transmission distance of more than 1000 km at 80 Gbits/s with the combination of the pre- and post-compensation technique. To efficiently suppress the effect of ASE and improve optical signal-to- noise ratio （OSNR）, the bandwidth frequency of optical receiver filter was found to be at least equal to bit rate.