Improvement of DBR routing protocol in underwater wireless sensor networks using fuzzy logic and bloom filter.

Routing protocols for underwater wireless sensor networks (UWSN) and underwater Internet of Things (IoT_UWSN) networks have expanded significantly. DBR routing protocol is one of the most critical routing protocols in UWSNs. In this routing protocol, the energy consumption of the nodes, the rate of loss of sent packets, and the rate of drop of routing packets due to node shutdown have created significant challenges. For this purpose, in a new scenario called FB-DBR, clustering is performed, and fuzzy logic and bloom filter are used in each cluster's new routing protocol in underwater wireless sensor networks. Due to the fuzzy nature of the parameters used in DBR, better results are obtained and bloom filters are used in routing tables to compensate for the deceleration. as the average number of accesses to routing table entries, dead nodes, Number of Packets Sent to Base Station (BS), Number of Packets Received at BS, Packet Dropped, and Remaining Energy has improved significantly.

An adaptive under-frequency optimal control strategy for power system combined pumped storage and under-frequency load shedding.

With the construction and development of ultra-high voltage (UHV) power grids, large-scale, long-distance power transmission has become common. A failure of the connecting line between the sending-end power grid and the receiving-end power grid will cause a large-scale power shortage and a frequency drop in the receiving-end power grid, which can result in the frequency collapse. Presently, under-frequency load shedding (UFLS) is adopted for solving the frequency control problem in emergency under-frequency conditions, which can easily cause large load losses. In this context, a frequency coordination optimal control strategy is proposed, which combines the mode transition of pumped storage units with UFLS to deal with emergency under-frequency problems. First, a mathematical model of the frequency dynamic response is established, which combines the mode transition of pumped storage units with UFLS based on a single-machine equivalent model. Then, an optimal model of the minimal area of the power system's operation frequency trajectory is introduced, yielding the optimal frequency trajectory, and is used for obtaining the action frequency of the joint control strategy. A simulated annealing algorithm based on the perturbation analysis is proposed for solving the optimal model, and the optimal action frequency is obtained that satisfies the transient frequency offset safety constraint of the power system. Thus, the joint optimal control of the mode transition of the pumped storage units and UFLS is realized. Finally, the EPRI-36 bus system and China's actual power grid are considered, for demonstrating the efficiency of the proposed strategy.

Design of combined stationary and mobile battery energy storage systems.

To minimize the curtailment of renewable generation and incentivize grid-scale energy storage deployment, a concept of combining stationary and mobile applications of battery energy storage systems built within renewable energy farms is proposed. A simulation-based optimization model is developed to obtain the optimal design parameters such as battery capacity and power ratings by solving a multi-objective optimization problem that aims to maximize the economic profitability, the energy provided for transportation electrification, the demand peak shaving, and the renewable energy utilized. Two applications considered for the stationary energy storage systems are the end-consumer arbitrage and frequency regulation, while the mobile application envisions a scenario of a grid-independent battery-powered electric vehicle charging station network. The charging stations receive supplies from the energy storage system that absorbs renewable energy, contributing to a sustained DC demand that helps with revenues. Representative results are presented for two operation modes and different sets of weights assigned to the objectives. Substantial improvement in the profitability of combined applications over single stationary applications is shown. Pareto frontier of a reduced dimensional problem is obtained to show the trade-off between design objectives. This work could pave the road for future implementations of the new form of energy storage systems.

Marine predators algorithm for solving single-objective optimal power flow.

This study presents a nature-inspired, and metaheuristic-based Marine predator algorithm (MPA) for solving the optimal power flow (OPF) problem. The significant insight of MPA is the widespread foraging strategy called the Levy walk and Brownian movements in ocean predators, including the optimal encounter rate policy in biological interaction among predators and prey which make the method to solve the real-world engineering problems of OPF. The OPF problem has been extensively used in power system operation, planning, and management over a long time. In this work, the MPA is analyzed to solve the single-objective OPF problem considering the fuel cost, real and reactive power loss, voltage deviation, and voltage stability enhancement index as objective functions. The proposed method is tested on IEEE 30-bus test system and the obtained results by the proposed method are compared with recent literature studies. The acquired results demonstrate that the proposed method is quite competitive among the nature-inspired optimization techniques reported in the literature.

Classification of abnormal location in medium voltage switchgears using hybrid gravitational search algorithm-artificial intelligence.

In power system networks, automatic fault diagnosis techniques of switchgears with high accuracy and less time consuming are important. In this work, classification of abnormal location in switchgears is proposed using hybrid gravitational search algorithm (GSA)-artificial intelligence (AI) techniques. The measurement data were obtained from ultrasound, transient earth voltage, temperature and sound sensors. The AI classifiers used include artificial neural network (ANN) and support vector machine (SVM). The performance of both classifiers was optimized by an optimization technique, GSA. The advantages of GSA classification on AI in classifying the abnormal location in switchgears are easy implementation, fast convergence and low computational cost. For performance comparison, several well-known metaheuristic techniques were also applied on the AI classifiers. From the comparison between ANN and SVM without optimization by GSA, SVM yields 2% higher accuracy than ANN. However, ANN yields slightly higher accuracy than SVM after combining with GSA, which is in the range of 97%-99% compared to 95%-97% for SVM. On the other hand, GSA-SVM converges faster than GSA-ANN. Overall, it was found that combination of both AI classifiers with GSA yields better results than several well-known metaheuristic techniques.

Distributed optimal power flow.

OBJECTIVE: The objectives of this paper are to 1) construct a new network model compatible with distributed computation, 2) construct the full optimal power flow (OPF) in a distributed fashion so that an effective, non-inferior solution can be found, and 3) develop a scalable algorithm that guarantees the convergence to a local minimum. EXISTING CHALLENGES: Due to the nonconvexity of the problem, the search for a solution to OPF problems is not scalable, which makes the OPF highly limited for the system operation of large-scale real-world power grids-"the curse of dimensionality". The recent attempts at distributed computation aim for a scalable and efficient algorithm by reducing the computational cost per iteration in exchange of increased communication costs. MOTIVATION: A new network model allows for efficient computation without increasing communication costs. With the network model, recent advancements in distributed computation make it possible to develop an efficient and scalable algorithm suitable for large-scale OPF optimizations. METHODS: We propose a new network model in which all nodes are directly connected to the center node to keep the communication costs manageable. Based on the network model, we suggest a nodal distributed algorithm and direct communication to all nodes through the center node. We demonstrate that the suggested algorithm converges to a local minimum rather than a point, satisfying the first optimality condition. RESULTS: The proposed algorithm identifies solutions to OPF problems in various IEEE model systems. The solutions are identical to those using a centrally optimized and heuristic approach. The computation time at each node does not depend on the system size, and Niter does not increase significantly with the system size. CONCLUSION: Our proposed network model is a star network for maintaining the shortest node-to-node distances to allow a linear information exchange. The proposed algorithm guarantees the convergence to a local minimum rather than a maximum or a saddle point, and it maintains computational efficiency for a large-scale OPF, scalable algorithm.

A Review on Lithium-Ion Battery Separators towards Enhanced Safety Performances and Modelling Approaches.

In recent years, the applications of lithium-ion batteries have emerged promptly owing to its widespread use in portable electronics and electric vehicles. Nevertheless, the safety of the battery systems has always been a global concern for the end-users. The separator is an indispensable part of lithium-ion batteries since it functions as a physical barrier for the electrode as well as an electrolyte reservoir for ionic transport. The properties of separators have direct influences on the performance of lithium-ion batteries, therefore the separators play an important role in the battery safety issue. With the rapid developments of applied materials, there have been extensive efforts to utilize these new materials as battery separators with enhanced electrical, fire, and explosion prevention performances. In this review, we aim to deliver an overview of recent advancements in numerical models on battery separators. Moreover, we summarize the physical properties of separators and benchmark selective key performance indicators. A broad picture of recent simulation studies on separators is given and a brief outlook for the future directions is also proposed.

Power Outage: An Ignored Risk Factor for COPD Exacerbations.

BACKGROUND: COPD is the third leading cause of death in the United States, with 16 million Americans currently experiencing difficulty with breathing. Power outages could be life-threatening for those relying on electricity. However, significant gaps remain in understanding the potential impact of power outages on COPD exacerbations. RESEARCH QUESTION: The goal of this study was to determine how power outages affect COPD exacerbations. STUDY DESIGN AND METHODS: Using distributed lag nonlinear models controlling for time-varying confounders, the hospitalization rate during a power outage was compared vs non-outage periods to determine the rate ratio (RR) for COPD and its subtypes at each of 0 to 6 lag days in New York State from 2001 to 2013. Stratified analyses were conducted according to sociodemographic characteristics, season, and clinical severity; changes were investigated in numerous critical medical indicators, including length of stay, hospital cost, the number of comorbidities, and therapeutic procedures between the two periods. RESULTS: The RR of COPD hospitalization following power outages ranged from 1.03 to 1.39 across lag days. The risk was strongest at lag0 and lag1 days and lasted significantly for 7 days. Associations were stronger for the subgroup with acute bronchitis (RR, 1.08-1.69) than for cases of acute exacerbation (RR, 1.03-1.40). Compared with non-outage periods, the outage period was observed to be $4.67 thousand greater in hospital cost and 1.38 greater in the number of comorbidities per case. The average cost (or number of comorbidities) was elevated in all groups stratified according to cost (or number of comorbidities). In contrast, changes in the average length of stay (-0.43 day) and the average number of therapeutic procedures (-0.09) were subtle. INTERPRETATION: Power outages were associated with a significantly elevated rate of COPD hospitalization, as well as greater costs and number of comorbidities. The average cost and number of comorbidities were elevated in all clinical severity groups.

Continuous dynamic sliding mode control strategy of PWM based voltage source inverter under load variations.

For closed-loop controlled DC-AC inverter system, the performance is highly influenced by load variations and online current measurement. Any variation in the load will introduce unwanted periodic error at the inverter output voltage. In addition, when the current sensor is in faulty condition, the current measurement will be imprecise and the designed feedback control law will be ineffective. In this paper, a sensorless continuous sliding mode control (SMC) scheme has been proposed to address these issues. The chattering effect due to the discontinuous switching nature of SMC has been attenuated by designing a novel boundary-based saturation function where the selection of the thickness of boundary is dependent to the PWM signal generation of the inverter. In order to remove the dependency on the current sensor, a particle swarm optimization(PSO) based modified observer is proposed to estimate the inductor current in which the observer gains are optimized using PSO by reducing the estimation errors cost function. The proposed dynamic smooth SMC algorithm has been simulated in MATLAB Simulink environment for 0.2-kVA DC-AC inverter and the results exhibit rapid dynamic response with a steady-state error of 0.4V peak-to-peak voltage under linear and nonlinear load perturbations. The total harmonic distortion (THD) is also reduced to 0.20% and 1.14% for linear and non-linear loads, respectively.

The Medical, Public Health, and Emergency Response to the Impact of 2017 Hurricane Irma in Cuba.

In 2017, Cuba was pummeled by Hurricane Irma, one of the strongest and most devastating Atlantic basin hurricanes in history. Twelve of Cuba's 15 provinces and 90 percent of the population were affected, and there was island-wide loss of electrical power. Despite the significant damage, ongoing economic hardships, and the political realities that required Cuba to handle the situation without response support from other nations, Cuba's recovery was swift and effective. Cuba's disaster self-sufficiency and timely response to Hurricane Irma was grounded on 5 decades of disaster planning coupled with ongoing evolution of disaster risk reduction and management strategies. While the central command center, with local dispatch response teams, and mandated citizen engagement are features unique to Cuba's political structure, in this study, we highlight 5 defining attributes of Cuba's hurricane response that can constructively inform the actions of other island and coastal nations vulnerable to Atlantic tropical cyclones. These attributes are: (1) actively learning and incorporating lessons from past disaster events, (2) integrating healthcare and public health professionals on the frontlines of disaster response, (3) proactively engaging the public in disaster preparedness, (4) incorporating technology into disaster risk reduction, and (5) infusing science into risk planning. In terms of hurricane response, as a geopolitically isolated nation, Cuba has experienced particular urgency when it comes to protecting the population and creating resilient infrastructure that can be rapidly reactivated after the onslaught of storms of ever-increasing intensity. This includes planning for worsening future disaster scenarios based on a clear-eyed appreciation of the realities of climate change.

Superior "green" electrode materials for secondary batteries: through the footprint family indicators to analyze their environmental friendliness.

As secondary batteries are becoming the popular production of industry, especial for lithium ion batteries (LIBs), the degree of environmental friendliness will gather increasing attention to their products of the whole life cycle. The research combines the life cycle assessment (LCA) and footprint family definition to establish a framework to calculate the footprint family of secondary battery materials. Through the method, we calculated the values of carbon footprint, water footprint, and ecological footprint about this eight kinds of secondary cathode battery materials with Ni-MH, Li1.2Ni0.2Mn0.6O2/C, LiNi1/3Co1/3Mn1/3O2/C, LiNi0.8Co0.2O2/C, LiFePO4/C, LiFe0.98Mn0.02PO4/C, FeF3(H2O)3/C, and NaFePO4/C. When comparing and analyzing their values in each footprint, it can summarize the evaluation method for some secondary batteries by footprint indicators and construct the evaluation system. Through the comprehensive evaluation of footprint family system, the NaFePO4/C battery gets the best performance of three main footprints when combining 1 kg of cathode materials, while Ni-MH is opposite. Hence, among these eight batteries environmental impacts evaluation, the NaFePO4/C battery is regarded as the superior "green" battery, albeit the current application is restricted because of the synthesis limitation on large scale and energy density of storage. In LIBs comparison, the FeF3(H2O)3 material shows its characteristics of environmental friendliness, which is expected to be a greener battery material of LIB. In conventional LIBs, the iron-containing cathode materials show lower environmental burden than ternary cathode materials. We can reduce environmental impacts through developing new advanced materials and reducing the content of high sensitivity element in raw materials.

Pulse generator battery life in deep brain stimulation: out with the old in with the less durable?

BACKGROUND: Battery life of the most commonly used implantable pulse generators in deep brain stimulation is limited. Device replacement is costly and may expose patients to additional risks. Driven by the observation that in our experience newer generation devices seemed to need earlier replacement than the older generation, we aimed to retrospectively analyze the battery life of two generations of non-rechargeable devices, manufactured by a single company (Medtronic, USA). METHODS: Battery life of 281 devices in 165 patients was taken into account for data analysis. This represented 243 older generation devices (Kinetra and Soletra) and 38 newer generation devices (Activa). RESULTS: The battery life of older generation stimulators was 2-fold longer than the newer generation. CONCLUSIONS: Newer devices are more versatile than the older generation. Their battery life is however significantly shorter. Development of next-generation devices needs to address this issue in order to limit health risks and reduce financial costs.

Evaluating exposure from electric fields in a high voltage switchyard according to the EU directive.

An assessment according to Directive 2013/35/EU of exposure in a 400 kV switchyard has been performed. Part of the body was exposed to electric field strength above the high action level. We therefore performed simulations of the electric fields induced in the body to assess these accoding to the exposure limit values (ELVs). The simulations show that as long as the body is not grounded nor touching any grounded metallic objects, worker exposure is compliant with the directive. When grounded metallic objects are touched with hand or foot the ELV are exceeded. The ELV is exceeded already at very low contact currents (2-3 µA) in the finger. If not appropriate measures are taken, this would lead to a severe limitation of the work tasks that can be performed in switchyards.

Feasibility of Simulation-Based Medical Education in a Low-Income Country: Challenges and Solutions From a 3-year Pilot Program in Uganda.

STATEMENT: Simulation is relatively new in many low-income countries. We describe the challenges encountered, solutions deployed, and the costs incurred while establishing two simulation centers in Uganda. The challenges we experienced included equipment costs, difficulty in procurement, lack of context-appropriate curricula, unreliable power, limited local teaching capacity, and lack of coordination among user groups. Solutions we deployed included improvisation of equipment, customization of low-cost simulation software, creation of context-specific curricula, local administrative support, and creation of a simulation fellowship opportunity for local instructors. Total costs for simulation setups ranged from US $165 to $17,000. For centers in low-income countries trying to establish simulation programs, our experience suggests that careful selection of context-appropriate equipment and curricula, engagement with local and international collaborators, and early emphasis to increase local teaching capacity are essential. Further studies are needed to identify the most cost-effective levels of technological complexity for simulation in similar resource-constrained settings.

Fixed-Life or Rechargeable Battery for Deep Brain Stimulation: Which Do Patients Prefer?

BACKGROUND: Deep brain stimulation (DBS) is increasingly used to treat a wide variety of neurological and psychiatric disorders. Implantable pulse generators (implantable pulse generators/batteries) for DBS were originally only available as a nonrechargeable option. However, there is now a choice between fixed-life and rechargeable batteries, with each having their own advantages and disadvantages. The extent of patient involvement in the choice of battery and the factors that matter to them have not been well studied. METHODS: Thirty consecutive adult patients with movement disorders attending a pre-DBS clinic were offered a choice of fixed-life or rechargeable battery and completed a questionnaire after the consultation on which factors influenced their decision. RESULTS: Nineteen patients (63%) chose the fixed-life battery and 11 patients (37%) chose the rechargeable battery. There were no significant differences in age, sex, underlying disease, disease duration or Unified Parkinson's Disease Rating Scale (UPDRS) (part 3) score (for patients with Parkinson disease) between those who chose the fixed-life vs. rechargeable battery. Most patients were not concerned about the size of the battery. Equal numbers were concerned about surgery to replace the battery, and less than half were concerned about the need to recharge the battery. More than half of patients felt that an acceptable charging frequency was monthly or yearly, and all patients felt that an acceptable charging duration was less than 1 hour, with half of all patients choosing less than 30 min. The main reasons cited for choosing the fixed-life battery were convenience and concern about forgetting to recharge the battery. The main reason for choosing the rechargeable battery was the avoidance of further surgery. DISCUSSION: Most patients in this adult cohort with movement disorders chose the fixed-life battery. The better lifestyle associated with a fixed-life battery is a major factor influencing their choice. Rechargeable batteries may be more acceptable if the recharging process is improved, more convenient, and discreet. CONFLICT OF INTEREST: The authors' institution has received educational grants from Medtronic, Abbott, and Boston Scientific companies.

Button Battery Safety: Industry and Academic Partnerships to Drive Change.

The pediatric button battery (BB) hazard has been recognized for several decades. In 2012, the National Button Battery Task Force was established, and most manufacturers have improved warning labels, more secure packaging, and made BB compartments in products are more secure. Tissue neutralization before BB removal (ie, honey or sucralfate/Carafate®) is an effective way to reduce the rate of BB injury. In absence of visible perforation, 0.25% sterile acetic acid esophageal tissue irrigation at time of BB removal is recommended as a neutralization strategy to mitigate injury progression. Future BB design changes could eliminate esophageal tissue injury.

Predicted longevity of contemporary cardiac implantable electronic devices: A call for industry-wide "standardized" reporting.

BACKGROUND: Battery longevity is an important factor that may influence the selection of cardiac implantable electronic devices (CIEDs). However, there remains a lack of industry-wide standardized reporting of predicted CIED longevity to facilitate informed decision-making for implanting physicians and payers. OBJECTIVE: The purpose of this study was to compare the predicted longevity of current generation CIEDs using best-matched CIEDs settings to assess differences between brands and models. METHODS: Data were extracted for current model pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy-defibrillators (CRT-Ds) from product manuals and, where absent, by communication with the manufacturers. Pacemaker longevity estimations were based on standardized pacing outputs (2.5V, 0.40-ms pulse width, 500-Ω impedance) and pacing loads of 50% or 100% at 60 bpm. ICD and CRT-D longevity were estimated at 0% pacing and 15% atrial plus 100% biventricular pacing, with essential capacitor reforms and zero clinical shocks. RESULTS: Mean maximum predicted longevity of single- and dual-chamber pacemakers was 12.0 ± 2.1 and 9.8 ± 1.9 years, respectively. Use of advanced features such as remote monitoring, prearrhythmia electrogram storage, and rate response can result in ∼1.4 years of reduction in longevity. Mean maximum predicted longevity of ICDs and CRT-Ds was 12.4 ± 3.0 and 8.8 ± 2.1 years, respectively. Of note, there were significant variations in predicted CIED longevity according to device manufacturers, with up to 44%, 42%, and 44% difference for pacemakers, ICDs, and CRT-Ds, respectively. CONCLUSION: Contemporary CIEDs demonstrate highly variable predicted longevity according to device manufacturers. This may impact on health care costs and long-term clinical outcomes.

Electric multiple unit circulation plan optimization based on the branch-and-price algorithm under different maintenance management schemes.

For railway operators, one of many important goals is to improve the utilization efficiency of electric multiple units (EMUs). When operators design EMU circulation plans, EMU type restrictions are critical factors when assigning EMUs to the correct depots for maintenance. However, existing studies only consider that EMUs are maintained at their home depots. However, targeting that problem, in this paper, an optimization model for the EMU circulation planning problem that allows depots to be selected for EMU maintenance is proposed. This model aims at optimizing the number of used EMUs and the number of EMU maintenance tasks and simultaneously incorporates other important constraints, including type restrictions, on EMU maintenance and night accommodation capacity at depots. In order to solve the model, a branch-and-price algorithm is also developed. A case study of a real-world high-speed railway was conducted to compare and analyze the effects of different maintenance location constraints. The results show that the number of EMUs used will decrease under the maintenance sharing scheme, the number of EMU maintenance tasks can be reduced, and the time occupied in EMU maintenance will be released. In addition, the scheme of maintenance resources sharing and increases to mileage limits can effectively decrease the number of EMU maintenance tasks significantly. The model and algorithm can be used as an effective quantitative analysis tool for railway operators' decision-making processes in the EMU circulation planning problem.

Power outages and refrigerated medicines: The need for better guidelines, awareness and planning.

WHAT IS KNOWN AND OBJECTIVE: Vaccines and other pharmaceuticals are essential medical supplies that require continuous storage at specific temperatures to maintain viability. Power outages can lead to a break in the cold chain, resulting in the degradation of essential medicines. COMMENT: After a power outage, the stability of vaccines and other medicines can be difficult to ascertain. Many public health guidelines therefore recommend discarding potentially compromised pharmaceuticals unless the cold chain can be guaranteed-a costly endeavour. There are government guidelines aimed at minimizing exposure to high temperatures in the event of a power outage; however, the usefulness of these guidelines is uncertain. WHAT IS NEW AND CONCLUSION: The actual cost of vaccine and pharmaceutical loss due to a break in the cold chain is poorly studied and requires further research. Additional recommendations regarding the stability of specific medicines would also be a valuable resource.