Integrated circuit reliability testing

A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit

Average energy efficiency contours with multiple decoding policies

This letter addresses energy-efficient design in multi-user, single-carrier uplink channels by employing multiple decoding policies. The comparison metric used in this study is based on average energy efficiency contours, where an optimal rate vector is obtained based on four system targets: Maximum energy efficiency, a trade-off between maximum energy efficiency and rate fairness, achieving energy efficiency target with maximum sum-rate and achieving energy efficiency target with fairness. The transmit power function is approximated using Taylor series expansion, with simulation results demonstrating the achievability of the optimal rate vector, and negligible performance difference in employing this approximation

Review on automatic early skin cancer detection

Skin cancer is increasing in different countries especially in Australia. Early detection of skin cancer can treat melanoma successfully, therefore, curability and survival depends directly on removing melanoma in its early stages. Since clinical observations face to different fault for melanoma detection, the automatic diagnosis can help to increase the accuracy of detection. Reviewing the researches have done in skin cancer detection and providing the overview on automatic detection of skin cancer are the ultimate aims of this paper. It presents the literature on automatic skin cancer detection and describes the different steps of such process. © 2011 IEEE

Reducing the Peak to Average Power Ratio of LDS-OFDM signals

Low Density Signature-Orthogonal Frequency Division Multiplexing (LDS-OFDM) has been introduced recently as an efficient multiple access technique. High Peak to Average Power Ratio (PAPR) is an important obstacle to multicarrier communication systems. This paper concentrates on the PAPR investigation and its reduction for LDS-OFDM signals. Specifically, we will investigate the impact of subcarrier allocation schemes and the phases of the signatures on the PAPR of LDS-OFDM signals. Firstly, the PAPR of LDS-OFDM with conventional signatures is investigated. Then we propose two methods for PAPR reduction; Newman phases and DFT pre-coding. The former method is simple and doesn't imply changes in the system structure while the DFT pre-coding implies a modification in the system. Simulation results show that using Newman phases considerably reduces the PAPR of LDS-OFDM. Further PAPR reduction is achieved using DFT pre-coded LDS-OFDM on the cost of higher complexity