Efficient privacy-preserving classification construction model with differential privacy technology

To address the problem of privacy disclosure during data mining, a new privacy-preserving decision tree classification construction model based on a differential privacy-protection mechanism is presented. An efficient classifier that uses feedback to add two types of noise via Laplace and exponential mechanisms to perturb the calculation results are introduced to the construction algorithm that provides a secure data access interface for users. Different split solutions for attributes of continuous and discrete values are provided and used to optimize the search scheme to reduce the error rate of the classifier. By choosing an available quality function with lower sensitivity for making decisions and improving the privacy budget allocation methods, the algorithm effectively resists malicious attacks that depend on the background knowledge. The potential problem of obtaining personal information by guessing unknown sensitive nodes of tree-type data is solved correspondingly. The better privacy preservation and accuracy of this new algorithm are shown by simulation experiments. © 1990-2011 Beijing Institute of Aerospace Information.

Compact phase-lock loop for external cavity diode lasers

We present a compact, low-noise, and inexpensive optical phase-lock loop （OPLL） system to synchronize the frequency and the phase between two external cavity diode lasers. Based on a direct digital synthesizer tech- nique, a programmable radio-frequency generator is implemented as the reference signal source. The OPLL has a narrow beat note linewidth below 1 Hz and a residual mean-square phase error of 0.06 rad2 in a 10 MHz integration bandwidth. The experimental test results prove the competent performance of the system, which is promising as a low-budget choice in atomic physics applications.

Ultraviolet photodetector with bandpass characteristic based on a blend of PVK and PBD

We fabricate an ultraviolet photodetector based on a blend of poly （N-vinylcarbazole） （PVK） and 2- tert-butylphenyl-5-biphenyl-1, 3, 4-oxadiazole （PBD） using spin coating. The device exhibites a low dark current density of 2.2×10 3 μA/cm 2 at zero bias. The spectral response of the device shows a narrow bandpass characteristic from 300 to 355 nm, and the peak response is 18.6 mA/W located at 334 nm with a bias of –1 V. We also study the performances of photodetectors with different blend layer thicknesses. The largest photocurrent density is obtained with a blend of 90 nm at the same voltage.

Upstream dispersion management of 25 Gb/s duobinary and PAM-4 signals to support 0–40 km differential reach

We extensively discuss 25 Gb/s per wavelength capacity in both IEEE and ITU-T standardization to support the increasing bandwidth requirement. In this Letter, we propose to use the optical dispersion compensation technique in an optical line terminal（OLT） combined with a bandwidth-limited electro-absorption modulated laser in an optical network unit to achieve 25 Gb/s capacity for the upstream link. We evaluate the positive and negative dispersion tolerances of 25 Gb/s electrical duo-binary（EDB） and pulse-amplitude modulation（PAM-4） signals. We achieve 39.5 and 31 d B upstream loss budgets for the 25 Gb/s EDB and PAM-4 signals by using-600 and-500 ps∕nm optical dispersion compensation in OLT, respectively, both supporting 0–40 km differential reach.