This study presents a compact L-points discrete cosine transform (DCT) hardware accelerator for M-points Mel-scale Frequency Cepstral Coefficients (MFCC). The main contributions of this work can be summarized as 1) proposing an algorithm with lower complexity; 2) achieving higher accuracy performance; 3) implementing a low-cost accelerator with a unique group of cosine coefficients. For algorithm derivation, the proposed method converts the original formula into the type IV of discrete cosine transform (DCT-IV) with a preprocessing procedure. The kernel computation of DCT-IV can be further derived into the same cosine multiplication with the proposed preprocessing. Therefore, a total of (M-1) (L-1) additions, (M-1) L multiplications, and L coefficients are required for the computation. Compared with Jo et al.'s algorithm, the proposed method respectively reduces the number of additions and multiplications by 42.32 % and 41.67 %. Instead, the number of coefficients is increased by 33.33 %. Moreover, the proposed algorithm exhibits a higher peak signal-to-noise ratio (PSNR) value which is achieved at 90.1dB with a 16bit coefficient word length. For hardware realization, the FPGA implementation results show that it can operate at a clock rate of 135.85 MHz and requires only 113 combinational elements, 87 registers, 3 DSP multipliers, 64×16 bits RAM and 32×16 bits ROM. Overall, it would be a good choice for integrating MFCC applications in the future.INDEX TERMS discrete cosine transform (DCT); Hardware Accelerator; Mel-scale Frequency Cepstral Coefficients (MFCC)

Rodent infestations are a common problem that can result in several issues, including diseases, damage to property, and crop loss. Conventional methods of controlling rodent infestations often involve using mousetraps and applying rodenticides manually, leading to high manpower expenses and environmental pollution. To address this issue, we introduce a system for remotely monitoring rodent infestations using Internet of Things (IoT) nodes equipped with Long Range (LoRa) modules. The sensing nodes wirelessly transmit data related to rodent activity to a cloud server, enabling the server to provide real-time information. Additionally, this approach involves using images to auxiliary detect rodent activity in various buildings. By capturing images of rodents and analyzing their behavior, we can gain insight into their movement patterns and activity levels. By visualizing the recorded information from multiple nodes, rodent control personnel can analyze and address infestations more efficiently. Through the digital and quantitative sensing technology proposed at this stage, it can serve as a new objective indicator before and after the implementation of medication or other prevention and control methods. The hardware cost for the proposed system is approximately USD 43 for one sensor module and USD 17 for one data collection gateway (DCG). We also evaluated the power consumption of the sensor module and found that the 3.7 V 18,650 Li-ion batteries in series can provide a battery life of two weeks. The proposed system can be combined with rodent control strategies and applied in real-world scenarios such as restaurants and factories to evaluate its performance.

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Reversible data hiding enables the cover image to be restored from the stego image without any loss after the secret message is extracted. In this paper, we proposed a novel reversible data‐hiding scheme for high image quality based on the histogram‐shifting method. In our scheme, we proposed two mechanisms for choosing reference pixels according to the high correlation of adjacent pixels. The differences between reference pixels and their corresponding, neighboring, non‐reference pixels are exploited to hide secret messages according to the difference shifting mechanism. To achieve larger embedding capacity, the reference pixels are designed to further carry secret messages based on the interpolation prediction method. Experimental results showed that our proposed scheme achieved higher embedding payload while maintaining better visual quality of the images than did other schemes. Copyright © 2014 John Wiley & Sons, Ltd.