A Novel Complex Orthogonal Design for Space–Time Coding in Sensor Networks

In this paper, we propose a complex orthogonal design based on the theory of Finite projective plane. As most of the orthogonal designs incur low ratio of time diversity, the proposed complex orthogonal design has a relatively high ratio of time diversity. In addition, the proposed scheme has the following characteristics: (1) full spatial diversity (2) low rate (3) linear processing. We compare the proposed scheme with another complex design to show the tradeoffs. The proposed scheme can be of use for certain applications such as sensor networks and deep space exploration where there might be an imposed limit on the peak transmit power.     

Design of 100 μW Wireless Sensor Nodes for Biomedical Monitoring

Wireless sensor nodes span a wide range of applications. This paper focuses on the biomedical area, more specifically on healthcare monitoring applications. Power dissipation is the dominant design constraint in this domain. This paper shows the different steps to develop a digital signal processing architecture for a single channel electrocardiogram application, which is used as an application example. The target power consumption is 100 μW as that is the power energy scavengers can deliver. We follow a bottleneck-driven approach: first the algorithm is tuned to the target processor, then coarse grained clock-gating is applied, next the static as well as the dynamic dissipation of the digital processor is reduced by tuning the core to the target domain. The impact of each step is quantified. A solution of 11 μW is possible for both radio and DSP running the electrocardiogram algorithm.

Design of a Silicon Beam Resonator for a Novel Gas Sensor

研究了一种基于硅悬臂梁谐振器的新型气体传感器.该传感器在敏感环境中,可同时获得敏感膜电导率和质量变化,测量被测气体分子的荷质比,具有高灵敏度和高选择性.根据这一原理,针对气体传感器的需求,设计了硅悬臂梁谐振器化学传感器结构,进行了仿真优化,并采用MEMS表面牺牲层工艺制备该器件,激光频率仪测量验证了该微型谐振梁的谐振频率.     

Design of Laser Radar Fiber Optic Liquid Level Sensor System

A novel fiber optic liquid level sensor based on laser radar(ladar)is reported here.Using the perfect technique of ladar in which the phase of amplitude modulated light wave reflected from the liquid suface is compared with that of original modulation signal,the disance can be measured precisely.A special symmetric compensating coaxial optical system is proposed to eliminate many adverse effects.It realized the one-time electronic-free optical measurement on a simulated oil tank and achieves an accuracy of 0.3%.,within a temperature range of -10℃- 40℃ over a measuring of 0-10m。     

Novel Design for High Speed and Resolution Delta-sigma A/D Converter

The delta-sigma converter is one of the high speed and resolution analog-to-digital modulators. Its implementation needs the low oversampling technique and the multi-bit D/A converter. The noise induced by the multi-bit D/A converter becomes one of the key factors deteriorating the signal-to-noise rate of the delta- sigma A/D converter. A novel structure with signal unity transfunction, dynamic element matching（DEM） and noise-shaping is discussed. The method is investigated to design converter based on the proposed structure. The behavior simulation indicates that the structure and the design method are feasible.     

Novel Nano Structure for Green Energy Harvesting at 10 μm Thermal Radiation

In recent years, the potential of renewable green energy sources has been extensively studied. The proven technology which is photovoltaic solar cells strictly depends on daylight and produces low-efficiently. To overcome the restrictions, one technology studied is through harvesting the thermal radiation energy which can provide a 24-hour energy source. The continuity of energy sources promises very good energy conversion especially for military applications. This article presents a new structure that can harvest the abundant thermal radiation energy into usable energy at the wavelength of 10 m. A rectangular structure with a perturbation slit was designed to integrate with a rectifier circuit for green energy conversion. The slit tunnel junction guided the electromagnetic field into a junction where the energy could be collected and converted. An enhancement factor of approximately 110.6 can be achieved by a perturbation slit length of 1.0 m. The results extracted from the proposed design promise a better candidate to overcome the disadvantages of photovoltaic solar cells for energy harvesting devices.     

Design of a hiccup mode over-current protection circuit for DC–DC switching converters

In the paper an improvement hiccup mode over-current protection circuit is proposed and successfully applied in a typical current-mode DC–DC switching converter. It greatly reduces the circuit power consumption in prolonged overload conditions and can provide smooth self-recovery once the overload condition is removed. By reducing the switching frequency and over-current threshold value, it further improves the effect of over-current protection. The power consumption and implementation area are minimized by digital control. By simulation and verification with HSPICE, the output average current is only 16.8% of the conventional over-current mode in continuous over-current conditions. The presented circuits can automatically recover with the maximum load (5 A) when the overload is removed.     

Design and implementation of adaptive slope compensation in current mode DC–DC onverter

To improve the compensation for the inherent instability in a current mode converter, the adaptive slope compensation, giving attention to the problems of the traditional compensation on compensation accuracy, loading capability and turning jitter, is presented. Based on the analysis of current loop, by detecting the input and output voltage, converting the adaptive slope compensation current, the compensation of the current loop is optimized successfully. It can not only improve the compensation accuracy but also eliminate the over compensation, the turning jitter and the poor loading capability in the reported slope compensation. A power supply chip with adaptive slope compensation has been fabricated in a 0.35 μm CMOS process. The measurement results show that the chip starts up and operates steadily with the constant current limit under conditions of 5 V input voltage, from 10% to 100% duty cycle.     

A Novel Hybrid Optimization for Cluster‐Based Routing Protocol in Information-Centric Wireless Sensor Networks for IoT Based Mobile Edge Computing

Wireless Personal Communications - In present days, the utilization of mobile edge computing (MEC) and Internet of Things (IoT) in mobile networks offers a bottleneck in the evolving technological...     

Self-Assembled Nanoporous Metal–Organic Framework Monolayer Film for Osmotic Energy Harvesting

Osmotic energy represents a promising energy resource because it is sustainable and environmentally benign. Subnanoscale channels are considered as a competitive platform for generating this blue energy due to their highly selective and ultrafast ion transport. However, fabricating functional subnanochannels capable of high energy output remains challenging. Here, a heterogeneous subnanochannel membrane formed by coating a functionalized self-assembled metal−organic framework (MOF) monolayer (SAMM) film on a porous anodic aluminum oxide membrane, is reported. The SAMM film, with a thickness of ≈160 nm, is fabricated by self-assembly of poly(methyl methacrylate-co-vinylimidazole)-modified UiO-66-NH₂ nanoparticles at the water−air interface. In the SAMM, imidazole and NH₂ groups provide abundant positive charges, while the angstrom-scale windows act as ionic filters for selective screening of anions with different hydration diameters. As a result, the heterogeneous membrane exhibits excellent capacity for anion-selective transport, which contributes to an optimal osmotic power of 6.76 W m⁻² under a 100-fold NaCl gradient, as well as a high Cl⁻/SO₄²⁻ selectivity of ≈42.2. Further, the output power is increased to 10.5 W m⁻² by methylating imidazole moieties on the MOF surface. This work provides a facile and modular approach to fabricate subnanochannels for enabling highly selective and efficient osmotic energy conversion.     

Design of Optoelectric Detection Circuit for Difference Absorption Gas Sensor

Since the gas infrared absorption spectrum linewidth is only several nanometers occupying the source intensity of several in a thousand, it is even less than the noise of light source. The signal of gas absorption is submerged in the noise, so it is impossible to measure the concentration of gas with spectrum absorption directly. According to the principle and parameters of difference absorption system of CH_ 4 gas, a detection circuit consisted of the lock-in amplifier is designed. The experiment results indicated that the detection circuit can satisfy the demand of the whole system, and the limit concentration is 150×10~ -6 .     

Analysis and Experimental Study of Proportional-Integral Sliding Mode Control for DC／DC Converter

DC/DC converter using the proportional-integral (PI) sliding mode control (SMC)scheme is investigated, including the selection of the switching surface, the proof of the reaching condition and the existence condition of sliding motion. The sliding regime and the local stability are given. The implementation of the PI SMC is simpler than other SMC schemes and the steady-state error is eliminated. A prototype based on Buck converter is built up. The experimental results show that the dynamic performance and robustness to the parameter variations and external disturbances are improved.     

Novel Optical Fiber Gas Sensor for On-line Measurement of Methane

Based on analysis of near infrared spectral absorption of methane,absorption type optical fiber methane gas sensor with high sensitivity using DFB LD as a source is demonstrated. Light source modulation harmonic measurement is presented in this paper. In order to eliminate the noise, the ratio of the fundamental and second-harmonic signals is used. The mathematical model of gas concentration harmonic measurement is built up.The detection result of methane concentration is also shown. Experiments have proved a sensitivity of 28×10~(-6).     

Distributed and Energy Efficient Self-Organization for On–Off Wireless Sensor Networks

In this paper, we utilize clustering to achieve energy efficiency for the on–off wireless sensor network, whose member nodes alternate between active and inactive states. In the proposed Distributed and Energy Efficient Self Organization (DEESO) scheme, the head election is adjusted adaptively to the remaining battery levels of local active nodes, which is a completely distributed approach compared to LEACH that relying on other routing schemes to access global information. Furthermore, we apply the Adaptive Channel Assignment (ACA) to address the on-off topology changes. Simulation results show that DEESO delivers 184% amount of data to the base station as LEACH for the same amount of energy consumption and the effective network lifetime is extended by around 50%.     

A Design of Observers for a Discrete Chaotic System

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A Green Metal–Organic Framework-Cyclodextrin MOF: A Novel Multifunctional Material Based Triboelectric Nanogenerator for Highly Efficient Mechanical Energy Harvesting

The naturally available cyclodextrin has opened up a wide range of research avenues because of its superior characteristics such as being non-toxic, biocompatible, and edible. The cyclodextrin is the green multifunctional material that can add to the triboelectric series and extend its self-powered applications. The ultrasonic synthesized cyclodextrin metal–organic framework (CD-MOF) designed using sodium as a metal ion and cyclodextrin as a ligand for the triboelectric nanogenerator is reported. The various detailed characterizations of the CD-MOFs give an insight into the properties of the synthesized material. The Kelvin probe force microscopy suggests three types of CD-MOFs, exhibiting a positive potential. As per the surface potential, the output of the various CD-MOF based TENG is varied as alpha CD MOF/Teflon > gamma CD-MOF/Teflon > beta CD-MOF/Teflon. The alpha CD MOF/Teflon TENG produces an electrical output of 152 V, 1.2 μA, and 14.3 nC, respectively. The fabricated device output is utilized for powering numerous low-power electronics through a capacitor and bridge rectifier circuit. The multiunit Z-shaped TENG device is attached to various surfaces such as the shoe heel and the backside of the school bag, and the corresponding energy harvesting response is demonstrated.     

Effect of Substrate Temperature on Optical Characteristics of Silver Island Films for Harvesting Solar Energy

Due to their particular optical characteristics,metallic island films have the potential to significantly increase the energy conversion efficiency of solar cell.We experimentally and theoretically investigated the effect of substrate temperature on the morphologies and optical properties of the silver island films.At low temperature,below 300 ℃,as the substrate temperature increases.Compared to the films prepared at room temperature,the sizes of nanoparticles decrease and the Absorption peaks shift to shor...     

Automata Based Hybrid PSO–GWO Algorithm for Secured Energy Efficient Optimal Routing in Wireless Sensor Network

The main objective in wireless sensor networks is to exploit efficiently the sensor nodes and to prolong the lifetime of the network. The discussion of energy is a significant concern to extend the lifetime of the network. Moreover, a nature inspired hybrid optimization approach called hybrid Particle Swarm Optimization–Grey Wolf Optimizer (PSO–GWO) is used in this work to efficiently utilize the energy and to transmit the data securely in an augmented path. A Learning Dynamic Deterministic Finite Automata (LD²FA) has been innovated and initiated to learn the dynamic role of the environment. LD²FA is mainly used to provide the learned and accepted string to hybrid PSO–GGWO so that the routes are optimized. Hybrid PSO–GWO is used to choose the optimal next node for each path to obtain the optimal route. The simulation results are obtained in MATLAB for 100–700 sensor nodes in a region of 500 × 500 m² which demonstrate that the proposed LD²FA based Hybrid PSO–GWO algorithm obtains better results when compared with existing algorithms. It is observed that LD²FA based Hybrid PSO–GWO has an increase of 18% and 48% betterment in lifetime of the network than PSO and GLBCA, nearly 57% and 75% increase in network lifetime when compared with GA and LDC respectively. It also shows an improvement of 24% increase compared to cluster-based IDS, nearly a rise of 90% throughput when compared with lightweight IDS. The consumption of energy is reduced by 13% and 15% than PSO and GA and an increase of 15% utilization of energy than LDC. Therefore, LD²FA based Hybrid PSO–GWO is been considered to efficiently utilize energy in an optimal route.

     

Novel Design of HID Lamp Electronic Ballast for Automotive Systems

This paper presents a high intensity discharge（HID） lamp for automotive illumination. A novel type of ballast for HID is proposed without an acoustic resonance. The system consists of high frequency DC/DC converter,DC/AC inverter（SLA2403M）, high voltage igniter and a microcontroller unit（MCU）. The proposed ballast controls the complex start-up process and constant power process by programming on the rnicrocontroller. It is verified that experimental results agree well with the calculated ones. The ballast features such functions as failure protection, line under-voltage, line over-voltage, output short circuit and disconnection protections.     

Design of Photoelectric Detection Circuit in Linear Measuring System

The tructure,equivalent circuit,noise souces of silicon photodiode are analyzed.In order to improve the measuring linearity,we must choose the silicon photodiode with a large Rd,small Rs and I0 and under an operation state of output short-circuit.We must let the operation amplifier work in the current-voltage transfer form.Also we analyzed the effects of the input noise voltage,the input noise current,the input offset voltage,the input offset current of the operation amplifier and the noises of the silicon photodiode on the combined circuit of the operation amplifier with the silicon photodiode.Considering these factors,we can design the detective circuit with high response,sensitivity,stability,linearity and SNR.