$224.3 billion in 2017 with average annual growth of 38%, and According to Capgemini's 2016 report, the world's non-cash transaction volumes grew by 8.9% in 2014 to 387.3 billion and it was predicted that in 2015, it will increase by 10.1% to reach 426.3 billion [8]. As the mobile payment market is activated and mobile payment frequency used by users increased, the need for simplified payment has increased. In all digital environments including environments where financial infrastructure is

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Abstract:The growing concern about Indoor Air-Quality has accelerated the development of small, low-cost air-quality monitoring systems. These systems are capable of monitoring various indoor air pollutants in real time, notifying users about the current air-quality status and gathering the information to the central server. However, most Internet of Things (IoT)-based air-quality monitoring systems numerically present the sensed value per pollutant, making it difficult for general users to identify how polluted the air is. Therefore, in this paper, we first introduce a tiny air-quality monitoring system that we developed and, based on the system, we also test the applicability of the comprehensive Air-Quality Index (AQI), which is widely used all over the world, in terms of its capacity for a comprehensive indoor air-quality indication. We also develop design considerations for an IoT-based air-quality monitoring system and propose a real-time comprehensive indoor air-quality level indication method, which effectively copes with dynamic changes and is efficient in terms of processing and memory overhead.

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performance of turbo codes in a FH-SS system with partial band interference. In this paper, turbo codes are investigated in a slowThe outline of this paper is as follows. In Section 2, the system model, including details of the FH-SS model frequency-hopped spread spectrum (FH-SS) system with noise is present. This paper focuses on the implemen-we present our modifications to the turbo decoder for tion of a modified turbo decoder for this model. We FH-SS. Analytical performance bounds are derived in consider cases of known or unknown channel state and Section 4. Our simulation and bound numerical results are presented in Sections 5 and 6. In Section 7 , variable number of bits per hop. Our approach is to modify the calculation of branch transition probabilities we conclude by discussing the potential of turbo codes inherent in the decoder. Analytical bounds are derived in FH-SS and simulation is performed for coherent demodulation. The results drawn from this code are compared with a convolutional code.

Abstract-In this paper, turbo codes are investigated in a slow frequency-hopped spread spectrum (FH-SS) system with partialband jamming. In addition, full-band thermal noise is present. The channel model is that of a partial-band jammer in which a fraction of the frequency band is jammed and the remaining fraction is unjammed. This paper focuses on the implemention and performance of a modified turbo decoder for this model. We refer to the knowledge that each transmitted bit is jammed as channel state information. We consider cases of known or unknown channel state and variable number of bits per hop. Our approach is to modify the calculation of branch transition probabilities inherent in the original turbo decoder. For the cases with no side information and multiple bits per hop, we iteratively calculate channel state estimates. Analytical bounds are derived and simulation is performed for noncoherent demodulation. The performance of turbo codes is compared with a Reed-Solomon and a concatenated code comprised of a convolutional inner code and Reed-Solomon outer code.

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