Comparing Fault Prediction Models Using Change Request Data for a Telecommunication System

Many studies in the software reliability have attempted to develop a model for predicting the faults of a software module because the application of good prediction models provides the optimal resource allocation during the development period. In this paper, we consider the change request data collected from the field test of a large-scale software system and develop statistical models of the software module that incorporate a functional relation between the faults and some software metrics. To this end, we discuss the general aspect of regression method, the problem of multicollinearity and the measures of model evaluation. We consider four possible regression models including two stepwise regression models and two nonlinear models. Four developed models are evaluated with respect to the predictive quality.     

A 77 GHz mHEMT MMIC Chip Set for Automotive Radar Systems

A monolithic microwave integrated circuit (MMIC) chip set consisting of a power amplifier, a driver amplifier, and a frequency doubler has been developed for automotive radar systems at 77 GHz. The chip set was fabricated using a 0.15 µm gate‐length InGaAs/InAlAs/GaAs metamorphic high electron mobility transistor (mHEMT) process based on a 4‐inch substrate. The power amplifier demonstrated a measured small signal gain of over 20 dB from 76 to 77 GHz with 15.5 dBm output power. The chip size is 2 mm × 2 mm. The driver amplifier exhibited a gain of 23 dB over a 76 to 77 GHz band with an output power of 13 dBm. The chip size is 2.1 mm × 2 mm. The frequency doubler achieved an output power of –6 dBm at 76.5 GHz with a conversion gain of ?16 dB for an input power of 10 dBm and a 38.25 GHz input frequency. The chip size is 1.2 mm × 1.2 mm. This MMIC chip set is suitable for the 77 GHz automotive radar systems and related applications in a W‐band.     

Practical Second‐Order Correlation Power Analysis on the Message Blinding Method and Its Novel Countermeasure for RSA

Recently power attacks on RSA cryptosystems have been widely investigated, and various countermeasures have been proposed. One of the most efficient and secure countermeasures is the message blinding method, which includes the RSA derivative of the binary‐with‐random‐initial‐point algorithm on elliptical curve cryptosystems. It is known to be secure against first‐order differential power analysis (DPA); however, it is susceptible to second‐order DPA. Although second‐order DPA gives some solutions for defeating message blinding methods, this kind of attack still has the practical difficulty of how to find the points of interest, that is, the exact moments when intermediate values are being manipulated. In this paper, we propose a practical second‐order correlation power analysis (SOCPA). Our attack can easily find points of interest in a power trace and find the private key with a small number of power traces. We also propose an efficient countermeasure which is secure against the proposed SOCPA as well as existing power attacks.     

New BER Expression of Hierarchical M‐ary Phase Shift Keying

In‐phase/quadrature (I/Q) imbalances, which are generated by non‐ideal transceiver components, are inevitable physical phenomena that cause the performance of practical communication systems to be degraded. In this paper, we provide a new closed‐form expression for the bit error rate of hierarchical M‐ary phase shift keying with I/Q phase and amplitude imbalances and analyze the effect of I/Q imbalances on BER performance over an additive white Gaussian noise channel.     

A novel fully integrated transmitter front-end with high power-added efficiency

A novel fully integrated transmitter front-end with a simple structure is proposed to obtain both high power-added efficiency (PAE) and a compact RF-front structure. To have all these characteristics, a novel antenna operating as a radiator, a harmonic tuning circuit, and an output matching network of the power amplifier is proposed. Therefore, the direct integration of the output of the power amplifier and antenna can be achieved without any impedance transformers. From the measured results and fabrication, it is shown that the proposed transmitter front-end provides high PAE of 67.5% and compact and integrated RF-front structure by the size reduction of 43% compared with the conventional class-F active antenna for high PAE.     

Thermal Characteristics of a Laser Diode Integrated on a Silica‐Terraced PLC Platform

A spot‐size converted Fabry‐Perot laser diode (LD) was flip‐chip bonded to a silica‐terraced planar lightwave circuit (PLC) platform to examine the effect of the silica terrace on the heat dissipation of the LD module. From the measurement of the light‐current characteristics, it was discovered that the silica terrace itself is not a strong thermal barrier, but the encapsulation of the integrated LD with an index‐matching polymer resin more or less deteriorates the heat dissipation.     

An Efficient Synthesis of 2,8-Diazabicyclo[4.3.0]-nonane Derivatives via Intramolecular Cyclization Reaction

Novel 5-functionalized-2,8-diazabicyclo[4.3.0]nonane derivatives 5 were synthesized from epoxide 1 through 4 steps in 46.7～52.6% yield.