Search results

Full adder cells are building blocks of arithmetic circuits and affect the performance of the entire digital system. The purpose of this study is to provide a low-power and high-performance full adder cell.

Approximate computing is a novel paradigm that is used to design low-power and high-performance circuits. In this paper, a novel 1-bit approximate full adder cell is presented using the combination of complementary metal-oxide-semiconductor, transmission gate and pass transistor logic styles.

Simulation results confirm the superiority of the proposed design in terms of power consumption and power–delay product (PDP) criteria compared to state-of-the-art circuits. Also, the proposed full adder cell is applied in an 8-bit ripple carry adder to accomplish image processing applications including image blending, motion detection and edge detection. The results confirm that the proposed cell has premier compromise and outperforms its counterparts.

The proposed cell consists of only 11 transistors and decreases the switching activity remarkably. Therefore, it is a low-power and low-PDP cell.

The purpose of this study is to show that due to the emergence of the Internet of Things (IoT) industry in recent years, the demand for the higher integration of wireless communication systems with a higher data rate of transmission capacity and lower power consumption has increased tremendously. The radio frequency power amplifier (PA) design is getting more challenging and crucial. A PA for a 2.45 GHz IoT application using 0.18 µm complementary metal oxide semiconductor (CMOS) technology is presented in this paper.

The design consists of two stages, the driver and output stage, where both use a single-stage common source transistor configuration. In view of performance, the PA can deliver more than 20 dB gain from 2.4 GHz to 2.5 GHz.

The maximum output power achieved by PA is 13.28 dBm. As the PA design is targeted for Bluetooth low energy (BLE) transmitter use, a minimum of 10 dBm output power should be achieved by PA to transmit the signal in BLE standard. The PA exhibits a constant output third-order interception point of 18 dBm before PA becomes saturated after 10 dBm output power. The PA shows a peak power added efficiency of 17.82% at the 13.24 dBm output power.

The PA design exhibits good linearity up to 10 dBm out the PA design exhibits good linearity up to 10 dBm output power without sacrificing efficiency. At the operating frequency of 2.45 GHz, the PA exhibits a stability k-factor, the value of more than 1; thus, the PA design is considered unconditional stable. Besides, the PA shows the s-parameters performance of –7.91 dB for S11, –11.07 dB for S22 and 21.5 dB for S21.

Existing control circuits for piezoelectric energy harvesting (PEH) suffers from long startup time or high power consumption. This paper aims to design an ultra-low power control circuit that can harvest weak ambient vibrational energy on the order of several microwatts to power heavy loads such as wireless sensors.

A self-powered control circuit is proposed, functioning for very brief periods at the maximum power point, resulting in a low duty cycle. The circuit can start to function at low input power thresholds and can promptly achieve optimal operating conditions when cold-starting. The circuit is designed to be able to operate without stable DC power supply and powered by the piezoelectric transducers.

When using the series-synchronized switch harvesting on inductor circuit with a large 1 mF energy storage capacitor, the proposed circuit can perform 322% better than the standard energy harvesting circuit in terms of energy harvested. This control circuit can also achieve an ultra-low consumption of 0.3 µW, as well as capable of cold-starting with input power as low as 5.78 µW.

The intermittent control strategy proposed in this paper can drastically reduce power consumption of the control circuit. Without dedicated cold-start modules and DC auxiliary supply, the circuit can achieve optimal efficiency within one input cycle, if the input signal is larger than voltage threshold. The proposed control strategy is especially favorable for harvesting energy from natural vibrations and can be a promising solution for other PEH circuits as well.

Privacy and security of personal data is the prime concern in any communication. Security algorithms play a crucial role in privacy preserving and are used extensively. Therefore, these algorithms need to be effective as well as energy-efficient. Advanced Encryption Standards (AES) is one of the efficient security algorithms. The principal purpose of this research is to design Energy efficient implementation of AES, as it is one of the important aspects for a step toward green computing.

This paper presents a low voltage complementary metal oxide semiconductor (LVCMOS) based energy efficient architecture for AES encryption algorithm on Field Programmable Gate Array (FPGA) platform. The experiments are performed for five different FPGAs at different input/output standards of LVCMOS. Experiments are performed separately at two frequencies (default and 1.6 GHz).

The comparative study of total on-chip power consumption for different frequency suggested that LVCMOS12 performed best for all the FPGAs. Also, Kintex-7 Low Voltage was found to be the best performing FPGA. At 1.6 GHz frequency, the authors observed 55% less on-chip power consumption when switched from Artix-7 with LVCMOS33 (maximum power consuming combination) to Kintex-7 Low Voltage with LVCMOS12. Mathematical models are developed for the proposed design.

The green implementation of AES algorithm based on LVCMOS standards has not been explored yet by researchers. The energy efficient implementation of AES will certainly be beneficial for society as it will consume less power and dissipate lesser heat to environment.

We take Cumulative Prospect Theory (CPT) seriously by rigorously estimating structural models using the full set of CPT parameters. Much of the literature only estimates a subset of CPT parameters, or more simply assumes CPT parameter values from prior studies. Our data are from laboratory experiments with undergraduate students and MBA students facing substantial real incentives and losses. We also estimate structural models from Expected Utility Theory (EUT), Dual Theory (DT), Rank-Dependent Utility (RDU), and Disappointment Aversion (DA) for comparison. Our major finding is that a majority of individuals in our sample locally asset integrate. That is, they see a loss frame for what it is, a frame, and behave as if they evaluate the net payment rather than the gross loss when one is presented to them. This finding is devastating to the direct application of CPT to these data for those subjects. Support for CPT is greater when losses are covered out of an earned endowment rather than house money, but RDU is still the best single characterization of individual and pooled choices. Defenders of the CPT model claim, correctly, that the CPT model exists “because the data says it should.” In other words, the CPT model was borne from a wide range of stylized facts culled from parts of the cognitive psychology literature. If one is to take the CPT model seriously and rigorously then it needs to do a much better job of explaining the data than we see here.

The purpose of this paper is to design multiplexers (MUXs) based on ternary half subtractor and full subtractor using carbon nanotube field-effect transistors.

Conventionally, the binary logic functions are developed by using the binary decision diagram (BDD) systems. Each node in BDD is replaced by 2:1 MUX to implement the digital circuits. Similarly, in the ternary decision diagram, each node has to be replaced by 3:1 MUX. In this paper, ternary transformed BDD is used to design the ternary subtractors using 2:1 MUXs.

The performance of the proposed ternary half subtractor and full subtractor using the 2:1 MUX are compared with the 3:1 MUX-based ternary circuits. It has been observed that the delay, power and power delay product values are reduced, respectively, by 67.6%, 84.3%, 94.9% for half subtractor and 67.7%, 70.1%, 90.3% for full subtractor. From the Monte Carlo simulations, it is observed that the propagation delay and power dissipation of the proposed subtractors are increased by increasing the channel length due to process variations. The stability test is also performed and observed that the stability increases as the channel length and diameter are increased.

The proposed half subtractor and full subtractor show better performance over the existing subtractors.

The purpose of this paper rapid development of various voltage sag compensation techniques in DC bus using ultra-capacitors (UCs) provides satisfactory results when compared with required peak power demand for shorter duration. Later, UCs have been used as floating capacitors [1] [2]. Various UCs are available based on internal resistances which also rely on its manufacturing materials, similar to double layer capacitors.

This paper demonstrates UCs based voltage sag compensation at load side under different working modes of hydraulic pack (HP) in an armored fighting vehicle (AFV). The main sources to supply the HP are 24 V, 400 Ahr battery bank and 20 kW main generator. HP is considered to be the highest power load of a system. 2,500 A inrush current was drawn by HP during initial conditions, and also, this system works in both elevation and azimuth mode. Voltage sag has been varied from 15 to 24 V for different modes. But as per the military standard, electrical systems should operate between 18 and 32 V DC. Because of insufficient terminal voltage, required energy cannot be attained and supplied to the loads. The proposed topology compensated the voltage sag and maintains nominal voltage on a DC bus. The devised circuit has been verified under all possible operating loads such as continuous, intermittent and momentary. The same has been simulated using MATLAB/Simulink and was experimentally verified. The minimum voltage maintained in a DC bus is 22.2 V in simulation, while experimentally, it was 24.2 V.

For getting higher percentage of efficiency, secondary energy system configuration, mainly designed for electrical vehicles, is needed. It was implemented and same was tested with the fighting vehicle system[1]. The proposed configuration comprises of bank of an UC and a battery bank. The system was finally implemented in AFVs.

The goods vehicles made of UCs can hold very minimum energy because of minimum density of energy. The modified AFV can have minimum charging as well as discharging of rate of energy and, thus, power[3][4]. Thus, the proposed idea of modified vehicle system has influence over significant change in the state of charge.

Cross-layer approach in media access control (MAC) layer will address interference and jamming problems. Hybrid distributed MAC can be used for simultaneous voice, data transmissions in wireless sensor network (WSN) and Internet of Things (IoT) applications. Choosing the correct objective function in Nash equilibrium for game theory will address fairness index and resource allocation to the nodes. Game theory optimization for distributed may increase the network performance. The purpose of this study is to survey the various operations that can be carried out using distributive and adaptive MAC protocol. Hill climbing distributed MAC does not need a central coordination system and location-based transmission with neighbor awareness reduces transmission power.

Distributed MAC in wireless networks is used to address the challenges like network lifetime, reduced energy consumption and for improving delay performance. In this paper, a survey is made on various cooperative communications in MAC protocols, optimization techniques used to improve MAC performance in various applications and mathematical approaches involved in game theory optimization for MAC protocol.

Spatial reuse of channel improved by 3%–29%, and multichannel improves throughput by 8% using distributed MAC protocol. Nash equilibrium is found to perform well, which focuses on energy utility in the network by individual players. Fuzzy logic improves channel selection by 17% and secondary users’ involvement by 8%. Cross-layer approach in MAC layer will address interference and jamming problems. Hybrid distributed MAC can be used for simultaneous voice, data transmissions in WSN and IoT applications. Cross-layer and cooperative communication give energy savings of 27% and reduces hop distance by 4.7%. Choosing the correct objective function in Nash equilibrium for game theory will address fairness index and resource allocation to the nodes.

Other optimization techniques can be applied for WSN to analyze the performance.

Game theory optimization for distributed may increase the network performance. Optimal cuckoo search improves throughput by 90% and reduces delay by 91%. Stochastic approaches detect 80% attacks even in 90% malicious nodes.

Channel allocations in centralized or static manner must be based on traffic demands whether dynamic traffic or fluctuated traffic. Usage of multimedia devices also increased which in turn increased the demand for high throughput. Cochannel interference keep on changing or mitigations occur which can be handled by proper resource allocations. Network survival is by efficient usage of valid patis in the network by avoiding transmission failures and time slots’ effective usage.

Literature survey is carried out to find the methods which give better performance.

This study explored whether the critical incident management systems (CIMS) model can predict the EMS performance in the COVID-19 context. Past research has established the significance of early detection and response (ER) in the context of Ebola virus disease (EVD), prompting a question of whether the model can also be helpful in the COVID-19 context. Consequently, the authors assessed whether ER influences the impact of communication capacity (CC), reliable information channel (RC) and environment (EN) on COVID-19 EMS performance. Assessing these relationships will advance emerging infectious disease (EID) preparedness.

The authors employed standardized measurement instruments of the CIMS model (CC, ER, RC and EN) to predict the performance of COVID-19 EMS using structural equation modeling (SEM) in a study of 313 participants from frontline responders.

The results show that the relationship of ER and EN with COVID-19 EMS performance is positive, while that of EN on CC is negative. The relationship between EN and COVID-19 EMS performance was insignificant. Contrary to the hypothesis, CC was negatively significant to COVID-19 EMS performance due to poor communication capacities.

The authors acknowledge some limitations due to challenges faced in this study. First, Data collection was a significant limitation as these questionnaires were built and distributed in June 2020, but the response time was prolonged due to the recurring nature of the pandemic. The authors had wanted to implore the inputs of all stakeholders, and efforts were made to reach out to various Ministry of Health, the local CDC and related agencies in the region via repeated emails explaining the purpose of the study to no avail. The study finally used the frontline workers as the respondents. The authors used international students from various countries as the representatives to reach out to their countries' frontline workers. Second, since the study was only partially supported using the CIMS model, future studies may combine the CIMS model with other models or theories. Subsequent research reassesses this outcome in other contexts or regions. Consequently, further research can explore how CC can be improved with COVID-19 and another future EID in the region. This may improve the COVID-19 EMS performance, thereby expanding the lesson learned from the pandemic and sustaining public health EID response. Additionally, other authors may combine the CIMS model with other emergency management models or theories to establish a fully supported theoretical model in the context of COVID-19.

The findings have practical implications for incident managers, local CDCs, governments, international organizations and scholars. The outcome of the study might inform these stakeholders on future direction and contribution to EID preparedness. This study unfolds the impact of lessons learned in the region demonstrated by moderating early detection and responses with other constructs to achieve COVID-19 EMS performance. The findings reveal that countries that experienced the 2013–2016 Ebola outbreak, were not necessarily more prepared for an epidemic or pandemic, judging by the negative moderating impact of early detection and response. However, these experiences provide a foundation for the fight against COVID-19. There is a need for localized plans tailored to each country's situation, resources, culture and lifestyle. The localized plan will be to mitigate and prevent an unsustainable EID management system, post-epidemic fund withdrawals and governance. This plan might be more adaptable and sustainable for the local health system when international interventions are withdrawn after an epidemic. Public health EID plans must be adapted to each country's unique situation to ensure sustainability and constantly improve EID management of epidemics and pandemics in emergency response. The high to moderate importation risk in African countries shows Africa's largest window of vulnerability to be West Africa (Gilbert et al., 2020). Therefore, they should be in the spotlight for heightened assistance towards the preparedness and response for a future pandemic like COVID-19. The West African region has a low capacity to manage the health emergency to match the population capacities. The COVID-19 outbreak in West Africa undoubtedly inflicted many disruptions in most countries' economic, social and environmental circumstances. The region's unique challenges observed in this study with CC and reliable information channels as being negatively significant highlight the poor maintenance culture and weak institutions due to brain drain and inadequate training and monitoring. This outcome practically informs West African stakeholders and governments on aspects to indulge when trying to improve emergency preparedness as the outcomes from other regions might not be applicable.

This study explored the relevance of the CIMS model in the context of the COVID-19 pandemic, revealing different patterns of influence on COVID-19 EMS performance. In contrast to the extant literature on EVD, the authors found the moderating effects of ER in the COVID-19 context. Thus, the authors contribute to the COVID-19 EMS performance domain by developing a context-driven EMS model. The authors discuss the theoretical and practical implications.

The purpose of this paper is to design a suitable guard trace to reduce the electromagentic interference between two closely spaced high frequency transmission lines. A novel cross-shaped resonator combined via fence is passed down to alleviate far-end and near-end crosstalk (NEXT) in tightly coupled high-speed transmission lines. The distance between the adjacent transmission lines is increased stepwise as a function of trace width.

A rectangular-shaped resonator via fence is connected by a guard trace has been proposed to overcome the coupling between the traces that is separated by 2 W. Similarly, by creating a cross-shaped resonator via fence connected by guard trace that reduces the spacing further by 1.5 W.

A tightly coupled transmission line structure that needs separation by a designed unit cell structure. Further research needs to be conducted to improve the NEXT, far-end crosstalk (FEXT) and spacing between the transmission lines.

This study portrays a novel method that combines the resonators via fence with a minimum spacing between the tightly coupled transmission lines which reduce the NEXT and FEXT; thereby reducing the size of the routing area. The resultant test structures are characterized at high frequencies using time domain and frequency domain analysis. The following scattering parameters such as insertion loss, NEXT and FEXT of the proposed method are measured as 1.504 dB, >30 dB and >20 dB, respectively.