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In recent years, Artificial Intelligence (AI) systems have achieved revolutionary capabilities, providing intelligent solutions that surpass human skills in many cases. However, such capabilities come with power-hungry computation workloads. Therefore, the implementation of hardware acceleration becomes as fundamental as the software design to improve energy efficiency, silicon area, and latency of AI systems. Thus, innovative hardware platforms, architectures, and compiler-level approaches have been used to accelerate AI workloads. Crucially, innovative AI acceleration platforms are being adopted in application domains for which dependability must be paramount, such as autonomous driving, healthcare, banking, space exploration, and industry 4.0. Unfortunately, the complexity of both AI software and hardware makes the dependability evaluation and improvement extremely challenging. Studies have been conducted on both the security and reliability of AI systems, such as vulnerability assessments and countermeasures to random faults and analysis for side-channel attacks. This paper describes and discusses various reliability and security threats in AI systems, and presents representative case studies along with corresponding efficient countermeasures. 

A systematic photoluminescence study of Be‐doped GaN grown by metal‐organic chemical vapor deposition is presented. All Be‐doped samples show the ultraviolet luminescence (UVL_Be) band with a maximum at 3.38 eV and the yellow luminescence (YL_Be) band with a maximum at ≈2.15 eV in GaN:Be having various concentrations of Be. The UVL_Beband is attributed to the shallow state of the Be_Gaacceptor with a delocalized hole. The YL_Beband is caused by a Be‐related defect, possibly the polaronic state of the Be_Gaacceptor with the charge transition level at 0.3 eV above the valence band. This broad band exhibits unusual properties. In particular, it always shows two steps in its thermal quenching. The second step atT ≈ 200 K is attributed to the emission of holes from the 0.3 eV level to the conduction band. The origin of the first step remains unexplained.