Panwit Tuwanut

A survey on internet of things architecture, protocols, possible applications, security, privacy, real-world implementation and future trends

The Internet is dramatically evolving and creating various connectivity methodologies. The Internet of Things (IoT) is one of those methodologies which transforms current Internet communication to Machine-to-Machine (M2M) basis. Hence, IoT can seamlessly connect the real world and cyberspace via physical objects that embed with various types of intelligent sensors. A large number of Internet-connected machines will generate and exchange an enormous amount of data that make daily life more convenient, help making a tough decision and provide beneficial services. This paper not only describes about the evolution and how important of IoT in daily life, the generic architecture, its most widely used protocols, numerous possible applications but also concern over security and privacy issues in IoT, real-world implementation of IoT system by using Arduino and its future trends. The IoT probably becomes one of the most popular networking concepts that has the potential to bring out many benefits.

A Novel Monostable Multivibrator Circuit

This article represents a novel monostable multivibrator circuit in which width and height of the pulse output can be independent electronically adjusted. In addition, the pulse width of output is not restricted to be wider or narrower than that of input pulse as conventionally employed. Namely, there is no restriction on the width of input and output pulse, the circuits implementation is thus more convenient. The proposed circuit is composed of three OTAs, two resistors and one capacitor, basically constructed a simple pulse generator (Schmitt-trigger circuit). Therewith the compactness of the circuit, it is thus suitable to be fabricated for integrated circuit. The results of circuit simulation is accordance well with theoretical analysis.

Image Watermarking Using Joined Wavelet and Time Domain

This paper presents Image Watermarking Using Joined Wavelet and Time Domain. This method proposed has advantages above a single domain watermarking which are time domain or frequency domain. The advantages are that the output watermarked image is more robust and the result watermark after attacked from both geometric attacks and frequency attacks is better than the single watermarking method.

A novel versatile modulator circuit

In this paper, a novel versatile modulator that can function either as delta modulator, sigma-delta modulator, amplitude modulator and frequency modulator is proposed. The principle of the proposed scheme is based on Schmitt-trigger circuit and composed of a few components: three OTAs, one capacitor and two resistors. The advantage of this circuit is that the clock (carrier) signal employed for modulation is inherent in the circuit. The modulating signal is therefore an external input requirement. Based on the compactness of the circuit, it is suitable for IC realization. The computer simulation demonstrates the results which agree well with the theoretical analysis.

7 decade low frequency switched capacitor oscillator

A sine wave switched-capacitor (SC) oscillator based on feedback SC BPF oscillator is proposed. The advantage of this technique is high stability, constant amplitude at wide frequency range and suitability for amplitude control by output forced response technique. In addition, frequency tuning can be adjusted by clock control, without effect on stability. The experimental results conforming the validity of the theory are also presented.

Experimental performance evaluation of LoRaWAN: A case study in Bangkok

The Internet of Things (IoT) is a vision which real-world objects are part of the internet. Every object is uniquely identified, and accessible to the network. There are various types of communication protocol for connect the device to the Internet. One of them is a Low Power Wide Area Network (LPWAN) which is a novel technology use to implement IoT applications. There are many platforms of LPWAN such as NB-IoT, LoRaWAN. In this paper, the experimental performance evaluation of LoRaWAN over a real environment in Bangkok, Thailand is presented. From these experimental results, the communication ranges in both an outdoor and an indoor environment are limited. Hence, the IoT application with LoRaWAN technology can be reliable in limited of communication ranges.

FM bandwidth scaling by Frequency operation under injection locked phenomena based on multi-time variable analysis

This article, the FM bandwidth scaling technique under injection locked and super-harmonic injection locked phenomenon, which explained by forcing oscillation perspective with multi-time variable technique is presented. By forcing FM signal to harmonic oscillator, the FM bandwidth can be scaled. This scaling technique separated in two situations, the first one is an expansion technique under injection locked phenomenon, and the second one is a compression technique under super-harmonic injection locked phenomenon. The modified Colpitts oscillator is taken in examine, and principle verified by experimental result.

An Improvement Particle Swarm Optimization for Travelling Salesman Problem with the Mutation Operator

This document proposed improvement PSO with applying mutation operator for solving Travelling Salesman Problem. To PSO solve or decrease trapping in local optimum. From experiment results of this research show that results of PSO with applying mutation operator obtain better than results of normal PSO for solving TSP.

A Simple and Economic PWM and EA Modulator Circuit Based on Modified Source-Couple Oscillator

In this article, a simple and economic pulse width modulator (PWM) and sigma delta modulator (SigmaDelta) circuit which is based on the modified CMOS source couple voltage-control oscillator is presented. The circuit can work either as PWM or SigmaDelta modulator, depending on the condition of the two bias currents which are forced of the source couples. Namely, the circuit is a PWM when these two bias currents are out of phase. Otherwise, it is a SigmaDelta modulator when both bias currents are identical. In addition, another feature of the proposed circuit is that the modulated signal can be either in voltage or current format. Moreover, the proposed circuit provides wide range of frequency operation because of few numbers of CMOS in the circuit. Furthermore, the circuit is very suitable for realization in integrated circuits (ICs) form and can be employed for optical communication application. The simulation results of the circuit are demonstrated and agreed well with theoretical anticipation

Time quantization derivative PWM based one-bit DPCM

A new 1-bit DPCM (differential pulse code modulator) circuit based on the derivative PWM (pulse width modulation) signal is proposed. The main concept of the proposed technique is that the difference of the adjacent input sample resides in the duty cycle of the derivative PWM signal. Therefore, one-bit digital signal can be exploited from the derivative PWM waveform in which the quantization process is performed in time axis, not in conventional amplitude axis. The derivative PWM principled circuit, which is composed of 3 OTAs, 1 capacitor, and 2 resistors, provides the simplicity and compactness of the circuits structure. In addition, the sampling operation is inherent in the derivative PWM circuit thus only some additional components are required for the mentioned transformation process. Implicitly, the proposed circuit is suitable for integrated circuit fabricating technology. The PSPICE simulation outputs of the proposed technique have demonstrated the expected results. Also, SNR analysis of the quantization process is briefly discussed.