Emergency Dispatch Research Articles

Differences between the dispatch priority assessments of emergency medical dispatchers and emergency medical services: a prospective register-based study in Finland

BackgroundResponsive and efficient emergency medical services (EMS) require accurate telephone triage. In Finland, such services are provided by Emergency Response Centre Agency (ERC Agency). In 2018, a new Finnish computer-assisted emergency dispatch system was introduced: the Emergency Response Integrated Common Authorities (ERICA). After the introduction of ERICA, the appropriateness of EMS dispatch has not been investigated yet. The study´s objective is to determine the consistency between the priority triage of the emergency medical dispatcher (EMD) and the on-scene priority assessment of the EMS, and whether the priority assessment consistency varied among the dispatch categories.MethodsThis was a prospective register-based study. All EMS dispatches registered in the Tampere University Hospital area from 1 August 2021 to 31 August 2021 were analysed. The EMD’s mission priority triaged during the emergency call was compared with the on-scene EMS’s assessment of the priority, derived from the pre-set criteria. The test performance levels were measured from the crosstabulation of true or false positive and negative values of the priority assessment. Statistical significance was analysed using the chi-square test and the Kruskal–Wallis H test, and p-values < 0.05 were considered significant.ResultsOf the 6416 EMS dispatches analysed in this study, 36% (2341) were urgent according to the EMD’s dispatch priority, and of these, only 29% (688) were urgent according to the EMS criteria. On the other hand, 64% (4075) of the dispatches were non-urgent according to the EMD’s dispatch priority, of which 97% (3949) were non-urgent according to the EMS criteria. Moreover, there were differences between the EMD and EMS priority assessments among the dispatch categories (p < 0.001). The overall efficiency was 72%, sensitivity 85%, specificity 71%, positive predictive value 29%, and negative predictive value 97%.ConclusionWhile the EMD recognised the non-urgent dispatches with high consistency with the EMS criteria, most of the EMD’s urgent dispatches were not urgent according to the same criteria. This may diminish the availability of the EMS for more urgent missions. Thus, measures are needed to ensure more accurate and therefore, more efficient use of EMS resources in the future.

Abstract WMP47: Low Sensitivity Of Widely Used Emergency Dispatch Algorithm For Thrombectomy Patients - Implications For Mobile Stroke Units

Introduction: Widely used emergency dispatch algorithms such as the Advanced Medical Priority Dispatch System (AMPDS) have limited diagnostic accuracy for prehospital diagnosis of stroke. With advent of mobile stroke units (MSU), this inaccuracy prevents optimal dispatch to patients who may benefit. Expedited endovascular thrombectomy (EVT) is a major contributor to net benefit of MSUs. We assessed the accuracy of AMPDS for recognizing stroke in thrombectomy patients in the Australian state of Victoria. Methods: We included consecutive patients accepted for EVT (direct and secondary transfer) to The Royal Melbourne Hospital from 2007-2021 in whom linked AMPDS dispatch codes could be obtained from Ambulance Victoria. The primary outcome was the proportion of cases dispatched as stroke vs non-stroke with subgroup analyses of the effect of baseline clinical severity, metropolitan vs rural dispatch and time to thrombectomy. Chi square and Mann Whitney tests were used as appropriate. Results: A total of n=618 patients were included with baseline NIHSS 16 (IQR 10-20). Of these, only 62% (95% CI 58-66) were initially dispatched as suspected stroke, with the most common non-stroke diagnoses being “Unconscious/Fainting” (19.2%) and “Falls” (6.9%). Those with a higher baseline severity (NIHSS ≥10) were less likely to be classified as stroke than those with lower severity (59% vs 76%, p&lt;0.001), while no difference was found between metropolitan and rural patients (p=0.066). Overall, no significant time differences were found between stroke and non-stroke dispatches for ambulance dispatch to arterial access (median 208 vs 216 min, p=0.593) or hospital arrival to arterial access (median 42 vs 42 min, p=0.851). However, only 32 patients were treated on the MSU, which commenced operation November 2017. Conclusions: Almost 40% of thrombectomy patients did not receive an initial AMPDS dispatch of suspected stroke and those with higher baseline severity were more likely to be misclassified. Although time to thrombectomy was not significantly different between stroke vs non-stroke dispatches, MSU treatment was under-represented. Our findings have implications for emergency medical services and particularly mobile stroke units which rely on accurate stroke dispatch.

Increased Prehospital Emergency Medical Service Time Interval and Nontransport Rate of Patients With Fever Using Emergency Medical Services Before and After COVID-19 in Busan, Korea.

In Korea, patients with fever have been preemptively isolated to isolation beds in the emergency department (ED) since the coronavirus disease 2019 (COVID-19) pandemic began. However, isolation beds were not always available, and transport delays or failure (nontransport), especially for infants, were reported in the media. Few studies have focused on delays and failure in transporting fever patients to the ED. Therefore, this study aimed to examine and compare the emergency medical service (EMS) time interval and nontransport rate of patients with fever using EMSs before and after COVID-19. This retrospective observational study analyzed the prehospital EMS time interval and nontransport rate of fever patients who contacted EMSs in Busan, South Korea, from March 1, 2019 to February 28, 2022, using emergency dispatch reports. All fever patients (≥ 37.5°C) who contacted EMSs during this study were included. The EMS time interval was defined as the time between the patient's EMS call and ED arrival time. Nontransport was defined as a case recorded as not being transported in the emergency dispatch reports. The study population of 2019 was compared to the population of 2020 and 2021 with the independent t-test, Mann-Whitney U test, and χ² test. As a subgroup, the EMS time intervals and nontransport rates of infants with fever were compared before and after COVID-19. A total of 554,186 patients accessed the EMS during the study period, and 46,253 patients with fever were included. The EMS time interval (mean ± standard deviation, minutes) of fever patients was 30.9 ± 29.9 in 2019, 46.8 ± 127.8 in 2020 (P < 0.001) and 45.9 ± 34.0 in 2021 (P < 0.001). The nontransport rate (%) was 4.4 in 2019, 20.6 in 2020 (P < 0.001), and 19.5 in 2021 (P < 0.001). For infants with fever, the EMS time interval was 27.6 ± 10.8 in 2019, 35.1 ± 15.4 in 2020 (P < 0.001), and 42.3 ± 20.5 in 2021 (P < 0.001), and the nontransport rate (%) was 2.6 in 2019, 25.0 in 2020, and 19.7 in 2021. After the emergence of COVID-19, in Busan, the EMS time interval of fever patients was delayed, and approximately 20% of fever patients were not transported. However, infants with fever had shorter EMS time intervals and higher nontransport rates than the overall study population. A comprehensive approach, including prehospital and hospital ED flow improvements, is required beyond increasing the number of isolation beds.

소화수 배관의 수소 발생 메커니즘에 관한 연구

As the display manufacturing site has grown to the size of about 400 soccer fields, it has become more sophisticated and high-rise, and fire fighting pipes are also being constructed through various designs. Recently, an explosion accident occurred while discharging fire extinguishing water from S Electronics in Pyeongtaek, and the physical and chemical characteristics of the generated mechanism and piping material were studied through the investigation of the cause. Currently, there is no standard for discharge of digestive water by law, and the standard for use of piping is less than 1.2 Less than. White pipes, which are galvanized pipes made of SPP, can be used, and STS 304 pipes can be constructed at 1.2 Less higher. This study investigated the conditions under which hydrogen gas is generated when zinc and stagnant firewater react for a long time in an air pocket inside the white tube. It was studied that it was a definite factor through the reproducibility verification of the experiment, and the reaction time for water and zinc could be predicted through chemical analysis. In addition, there was a delay in emergency dispatch because there was no system or other prevention that could detect accidents in advance. It was also known through research whether rapid detection was possible through the installation of a hydrogen detection system at the digestive water outlet. Through this, it could be suggested to reflect the previous design of the gas leakage detector. It is hoped that this study will allow workers at manufacturing sites and related firefighting to understand the mechanism of hydrogen gas generation in fire extinguishing water pipes, so that there will be no casualties or property damage caused by explosions.

구급활동일지 분석을 통한 119구급대 출동 대기시간 확보 방안

The number of individuals using the 119 emergency medical service (EMS) unit is increasing annually, and the Metropolitan Fire Headquarters attempts to increase the number of service individuals and vehicles; however, this has not been performed. The n‘umber of dispatches of the existing 119 EMS Unit is increasing. According to the analysis of the 119 paramedics’ emergency activity log, the waiting time for the dispatch of the 119 EMS unit decreased because of the increase in the number of dispatches. Consequently no other dispatch was possible for the 119 EMS unit. Since new emergency dispatches cannot be performed if the 119 EMS is busy, there is a vacancy in their area of jurisdiction, resulting in a dispatch gap. If a cardiac arrest occurs in an area with a dispatch gap, a 119 EMS unit from another area will be dispatched, making it difficult to secure timely emergency services. In solution, we found that there were many dispatches for non-emergency patients, and if these non-emergency patients are transferred to the non-emergency units, the 119 EMS unit can effectively assist patients with cardiac arrest.

Use of emergency services for suicide attempts during the SARS-CoV-2 pandemic-aprevalence study

The pandemic has caused several changes in the emergency care system. The deployment figures in emergency medical services have shown atypical fluctuations. This has also been explained by changes in behavior and an increased sense of stress among the population. Existing research provides hints for the increased incidence of mental health symptoms in emergency care during ongoing pandemics. In this context, this paper examines the occurrence of emergency medical services calls related to the keyword suicide in relation to total calls. This is aretrospective cross-sectional study based on routine documentation from afire and rescue dispatch center with descriptive and exploratory data analyses. The data are divided by settlement-structural county types and compared with incidences and pandemic phases. Phase1 and2a show adecrease in the number of dispatches during the pandemic. In addition, there is ashift in the number of dispatch cases with acontext of suicide by structure types in phase3. Adecreased dispatch rate in the sparsely populated rural county is offset by an increase in the metropolitan area. Changes made to the control center system resulted in an increase in the number of dispatch cases in the context of suicide. Continuous mental health surveillance, including data collected by emergency medical services, can provide valuable insight. The study also highlights the need for standardization of emergency dispatch center data.

First Point of Contact: Can Procedural Justice Be Applied by Emergency Calltakers?

Abstract Emergency calltakers are the first point of contact for community members requesting police services. In the current period of demands for reform in the criminal justice system, where do these calltakers fit? Prior research indicates that emergency calltakers and dispatchers play a significant role in the criminal justice response, prompting reformers to examine whether justice improvements might be achieved through this group. One area of reform—procedural justice training for emergency calltakers—often applied to direct officer–citizen interactions—has been suggested as a possible avenue for improving the justice system’s legitimacy. Drawing from insights gained through a systematic observation study of police calltakers and dispatchers, this policy analysis raises questions and caveats about applying procedural justice concepts to calltaking.

Distance assistance for first aid in trauma: literature review and a draft of the dispatcher algorithm

Being a common cause of death and disability, injuries remain a highly relevant global public health problem. In Russia, injuries hold one of the leading positions in the structure of mortality of the population, causing significant social and economic losses for the country. While the likelihood of saving lives and preventing severe complications in injuries largely depends on the ability of witnesses of the incident to early and correctly provide first aid (FA) to the victims, the actual frequency of providing FA remains low. A promising way to involve untrained people in the process of providing FA is to remotely instruct witnesses of the incident by emergency dispatchers on how to give FA. This article discusses international experience of dispatcher assistance for FA in trauma and presents a draft of a universal Russian-language algorithm for remote dispatcher interviewing and advising witnesses of the incident on provision of FA in trauma, that was developed taking into account the current Russian and international guidelines. The algorithm is proposed for further appraisal and implementation in the practical work of emergency dispatchers as a basic component of the federal program of dispatcher assistance for FA.

Effect of Smartphone Dispatch of Volunteer Responders on Automated External Defibrillators and Out-of-Hospital Cardiac Arrests

Smartphone dispatch of volunteer responders to nearby out-of-hospital cardiac arrests (OHCAs) has emerged in several emergency medical services, but no randomized clinical trials have evaluated the effect on bystander use of automated external defibrillators (AEDs). To evaluate if bystander AED use could be increased by smartphone-aided dispatch of lay volunteer responders with instructions to collect nearby AEDs compared with instructions to go directly to patients with OHCAs to start cardiopulmonary resuscitation (CPR). This randomized clinical trial assessed a system for smartphone dispatch of volunteer responders to individuals experiencing OHCAs that was triggered at emergency dispatch centers in response to suspected OHCAs and randomized 1:1. The study was conducted in 2 main Swedish regions: Stockholm and Västra Götaland between December 2018 and January 2020. At study start, there were 3123 AEDs in Stockholm and 3195 in Västra Götaland and 24 493 volunteer responders in Stockholm and 19 117 in Västra Götaland. All OHCAs in which the volunteer responder system was activated by dispatchers were included. Excluded were patients with no OHCAs, those with OHCAs not treated by the emergency medical services, and those with OHCAs witnessed by the emergency medical services. Volunteer responders were alerted through the volunteer responder system smartphone application and received map-aided instructions to retrieve nearest available public AEDs on their way to the OHCAs. The control arm included volunteer responders who were instructed to go directly to the OHCAs to perform CPR. Overall bystander AED attachment, including those attached by volunteer responders and lay volunteers who did not use the smartphone application. Volunteer responders were activated for 947 patients with OHCAs. Of those, 461 were randomized to the intervention group (median [IQR] age of patients, 73 [61-81] years; 295 male patients [65.3%]) and 486 were randomized to the control group (median [IQR] age of patients, 73 [63-82] years; 312 male patients [65.3%]). Primary outcome of AED attachment occurred in 61 patients (13.2%) in the intervention arm vs 46 patients (9.5%) in the control arm (difference, 3.8% [95% CI, -0.3% to 7.9%]; P = .08). The majority of AEDs were attached by lay volunteers who were not using the smartphone application (37 in intervention arm, 28 in control). There were no significant differences in secondary outcomes. Among the volunteer responders using the application, crossover was 11% and compliance to instructions was 31%. Volunteer responders attached 38% (41 of 107) of all AEDs and provided 45% (16 of 36) of all defibrillations and 43% (293 of 666) of all CPR. In this study, smartphone dispatch of volunteer responders to OHCAs to retrieve nearby AEDs vs instructions to directly perform CPR did not significantly increase volunteer AED use. High baseline AED attachement rate and crossover may explain why the difference was not significant. ClinicalTrials.gov Identifier: NCT02992873.

Implementation of standardised and structured emergency call answering systems in German emergency dispatch centres in 2019

Implementation of standardised and structured emergency call answering systems in German emergency dispatch centres in 2019

Optimizing an Emergency Medical Dispatch System to Improve Prehospital Diagnosis and Treatment of Acute Coronary Syndrome: Nationwide Retrospective Study in China.

Acute coronary syndrome (ACS) is the most time-sensitive acute cardiac event that requires rapid dispatching and response. The medical priority dispatch system (MPDS), one of the most extensively used types of emergency dispatch systems, is hypothesized to provide better-quality prehospital emergency treatment. However, few studies have revealed the impact of MPDS use on the process of ACS care. This study aimed to investigate whether the use of MPDS was associated with higher prehospital diagnosis accuracy and shorter prehospital delay for patients with ACS transferred by an emergency medical service (EMS), using a national database in China. This retrospective analysis was based on an integrated database of China's MPDS and hospital registry. From January 1, 2016, to December 31, 2020, EMS-treated ACS cases were divided into before MPDS and after MPDS groups in accordance with the MPDS launch time at each EMS center. The primary outcomes included diagnosis consistency between hospital admission and discharge, and prehospital delay. Multivariable logistic regression and propensity score-matching analysis were performed to compare outcomes between the 2 groups for total ACS and subtypes. A total of 9806 ACS cases (3561 before MPDS and 6245 after MPDS) treated by 43 EMS centers were included. The overall diagnosis consistency of the after MPDS group (Cohen κ=0.918, P<.001) was higher than that of the before MPDS group (Cohen κ=0.889, P<.001). After the use of the MPDS, the call-to-EMS arrival time was shortened in the matched ACS cases (20.0 vs 16.0 min, P<.001; adjusted difference: -1.67, 95% CI -2.33 to -1.02; P<.001) and in the subtype of ST-elevation myocardial infarction (adjusted difference: -3.81, 95% CI -4.63 to -2.98, P<.001), while the EMS arrival-to-door time (20.0 vs 20.0 min, P=.31) was not significantly different in all ACS cases and subtypes. The optimized use of MPDS in China was associated with increased diagnosis consistency and a reduced call-to-EMS arrival time among EMS-treated patients with ACS. An emergency medical dispatch system should be designed specifically to fit into different prehospital modes in the EMS system on a regional basis.

Abstract 311: Performance of Video-assisted Cardiac Arrest Recognition Protocol for Emergency Medical Dispatch in Out-of-hospital Cardiac Arrest

Introduction: Cardiac arrest recognition in emergency medical dispatch (EMD) is an important process for initiation of telephone CPR that could lead to bystander CPR before emergency medical service (EMS) arrival. Video-assisted protocol was developed and implemented for better recognition of cardiac arrest suspected calls that recognition was uncertain under conventional audio-call dispatch. We tested the performance of video-assisted protocol after pilot implementation in a dispatch center. Methods: All emergency medical dispatch calls received by Seoul emergency dispatch center that used video-assisted recognition protocol from Jun. 2020 to Dec. 2020 were enrolled. The primary outcome was the presence of cardiac arrest at EMS arrival evaluated by EMS providers arrived at the scene. The predictive performance measure of video-assisted protocol was calculated including sensitivity and specificity with 95% confidence interval (CI). Result: During the study period, video-assisted protocol was used in 115 emergency calls that dispatchers were uncertain during initial audio-call. In 15 cases the dispatcher additionally recognized the case as cardiac arrest under video-assistance. Of recognized cases, 14 (93.3%) cases were cardiac arrest when EMS arrived at scene. The sensitivity (95% CI) and the specificity (95% CI) of video-assistance protocol were 63.6% (40.7 - 82.8) and 98.9% (94.2 - 100) respectively. Conclusion: Use of video-assisted protocol helped recognizing additional cardiac arrest cases that could not be recognized with the audio-call in the dispatch center. Technological and operational improvement should be continuously studied for better cardiac arrest recognition using video-assisted protocol during emergency call taking.

Food emergency dispatching method based on optimized fireworks algorithm

In order to solve the problem of food emergency dispatching under emergencies, a food emergency dispatching method based on the optimal fireworks algorithm was proposed. The fitness function was used to measure the individual merits of fireworks, the tabu table was set to avoid the fireworks algorithm falling into the local optimal, and the tournament strategy was adopted as the iterative strategy of fireworks population. The goal of the fitness function is to maximize the satisfaction of demand points and minimize the vehicle travel time.In order to accurately predict the amount of food required at the point of demand, an infectious disease model (SEIR) was used.By comparing with the basic fireworks algorithm and genetic algorithm, the simulation results show that the proposed algorithm has higher computational efficiency and can be used in food emergency dispatching.

Ambulance referrals to an Australian Poisons Information Centre: a retrospective series

Introduction For poisoned patients, ambulance services may be the first point of contact for medical attention. With limited training in toxicology, ambulance services are encouraged to contact the Poisons Information Centre (PIC) for advice. This study aims to characterise referrals to a PIC from a state ambulance service with the purpose of improving information delivery and efficient use of these services. Methods This was a retrospective observational series of referrals to an Australian state PIC from ambulance staff from 1 January 2020 to 31 December 2020. Referrals were identified through the PIC Pharmhos database where the call originated from either a paramedic or emergency dispatch officer. Call reports were reviewed to extract data on patient demographics, exposure details and advice provided by the PIC. Results There were 1537 calls regarding 1420 poisoning exposures over the 12-month period, with 117 (7.6%) follow-up calls, representing 4.1% (1537/37835) of total calls to the PIC. Initial calls originated from paramedics in 999/1420 (70.4%) referrals, with dispatch officers referring 421/1420 (29.6%). Paediatric patients aged <15 years were involved in 492/1420 (34.6%) exposures with the commonest age range being 1–4 years. Most referrals involved pharmaceuticals exposures (756/1420 [53.2%]) followed by chemicals (557/1420 [39.2%]) and drugs of abuse (69/1420 [4.9%]). The commonest agents involved were paracetamol followed by quetiapine and sertraline. The PIC advised no treatment following benign exposures in 617/1420 (43.5%) calls, first aid measures in 333/1420 (23.5%) calls, supportive measures in 339/1420 (23.9%) calls and specific treatment in 32/1420 (2.3%) calls. Referral to the hospital was advised in 761/1420 (53.6%) calls, the majority of these were following deliberate self-poisonings (428/1420 [30.1%]). Conclusions Ambulance staff commonly contact the PIC following benign exposures where no treatment is required. Ambulance referral to a PIC following suspected poisonings may have a role in preventing unnecessary transfer to hospital in poisoned patients.

Building “common knowledge” when responding to major road tunnel incidents: an inter-organisational focus group study

PurposeMajor incidents in tunnel environment will pose several challenges for the emergency service organisations in terms of heat, visibility and lack of experiences from working in confined environments. These aspects, in turn, could pose challenges to establish collaboration. This study aims to contribute to the field of collaborative tunnel responses by exploring how “common knowledge” (Edwards, 2011) is built by the emergency services organisations, that is, what the organisations consider important while working on a potentially common problem, and their motives for the interpretations and actions if a major tunnel incident occurs.Design/methodology/approachParticipants from the road traffic control centre, emergency dispatch centre, emergency medical service, rescue service and police were included in the study. Data from four focus group sessions was analysed using thematic analysis.FindingsThe study revealed that the tunnel environment presents specific aspects of how common knowledge was produced related to lifesaving and safety. The themes structuring mechanisms to reduce uncertainty, managing information for initial priorities, aligning responsibilities without hampering each other's work and adjusting actions to manage distance, illustrated how common knowledge was produced as crucial aspects to a collaborative response. Organising management sites, grasping and communicating risks, accessing the injury victims, was challenged by the confined environment, physical distances and imbalance in access to information and preparedness activities in tunnel environments.Originality/valueThis study offers new insights of common knowledge, by illustrating a motive perspective on collaborative responses in tunnel incidents. Creating interoperability calls not just for readiness for action and tunnel safety, but also training activities acknowledging different interpretations and motives to further develop tunnel responses.

Emergency Service Assistance for Injuries on Alpine Ski Slopes: A Cross-Sectional Study.

Injuries on alpine ski slopes have been described in cohorts of a reasonable sample size, but constant improvements in safety gear, increased use of airborne rescue, and safety measures during the coronavirus disease 2019 (COVID-19) pandemic mandate re-evaluation. Therefore, the purpose of this study was to evaluate skiing and snowboarding injuries, effectiveness of airborne rescue, and impact of the COVID-19 pandemic on a large sample size. Data on alpine injuries were prospectively collected from the state emergency services dispatch center in the state of Tyrol (Austria). A total of 10,143 patients were identified, with an average age of 33.5 years (SD = 20.36). The ski patrol was involved in 8,606 cases (84.9%) and some patients (n = 1,536; 15.1%) required helicopter rescue. A total of 10,143 patients were identified from the dataset of the emergency dispatch center. The most frequently injured region was the knee (30.2%), and it was followed by the shoulder (12.9%), the lower leg (9.5%), and the head/skull (9.5%). The present findings indicate that the most frequent site of injuries on alpine slopes is the knee, and life-threatening injuries are rare. Airborne rescue is very time-effective, however clinical studies with patient follow-up should be emphasized to determine the impact of airborne rescue on patient outcome. The present findings indicate that the duration of all rescue operations has been prolonged as a result of the introduction of safety measures during the COVID-19 pandemic.

Analysis of the influence of expressway emergencies on transmission speeds and travel delays

Expressway emergencies tend to cause traffic congestion, and understanding the travel time delays of on-road vehicles under different combinations of event scenarios and road traffic conditions is valuable for guiding the accurate emer-gency dispatch services. Most existing studies used methods that combine the Lighthill–Whitham–Richards (LWR) theory and basic traffic diagrams to solve this problem, but the discrete traffic flow characteristics caused by the pres-ence of heavy vehicles have not been considered, thus affecting the applicability of those results to road traffic charac-teristics in China. Moreover, there is a lack of systematic research on multiple combinations of unexpected event sce-narios and traffic conditions, and the guidance value of the previously obtained results is limited. In order to improve the applicability of the prediction model and accurately predict the severity of emergencies, based on a logistic model that is applicable to emergencies, a velocity–density model is constructed to describe discrete traffic flow characteris-tics. Based on LWR theory, the internal driving force of expressway traffic state evolution under emergency conditions is explored. Combined with real-time traffic flow data, the parameters of the logistic model are calibrated, and a lo-gistic velocity–density model is constructed using a goodness-of-fit test and a marching method, including the free-flow velocity, turning density and heavy vehicle mixing ratio. Thus, the problem that existing models lack applicability to road traffic characteristics in China is solved. Travel time delay is associated with the impact range of an emergency, and it is an effective index for evaluating the severity of emergency incidents. Thus, the travel time delays under differ-ent scenarios, different numbers of blocked lanes and different orthogonal combinations of approximate saturation conditions are explored, and the impacts of lane blockage on emergency incidents and travel time delays are obtained. The conclusions show that the presented logistic velocity–density model constructed based on discrete traffic flow characteristics can properly quantify the impact of the presence of heavy vehicles. Additionally, the results can provide theoretical support for handling emergencies and emergency rescues.

Extended belief rule-based method for the assessment of matching between rescue tasks and volunteers

PurposeThis paper aims to solve the major assessment problem in matching the satisfaction of psychological gratification and mission accomplishment pertaining to volunteers with the disaster rescue and recovery tasks.Design/methodology/approachAn extended belief rule-based (EBRB) method is applied with the method's input and output parameters classified based on expert knowledge and data from literature. These parameters include volunteer self-satisfaction, experience, peer-recognition, and cooperation. First, the model parameters are set; then, the parameters are optimized through data envelopment analysis (DEA) and differential evolution (DE) algorithm. Finally, a numerical mountain rescue example and comparative analysis between with-DEA and without-DEA are presented to demonstrate the efficiency of the proposed method. The proposed model is suitable for a two-way matching evaluation between rescue tasks and volunteers.FindingsDisasters are unexpected events in which emergency rescue is crucial to human survival. When a disaster occurs, volunteers provide crucial assistance to official rescue teams. This paper finds that decision-makers have a better understanding of two-sided match objects through bilateral feedback over time. With the changing of the matching preference information between rescue tasks and volunteers, the satisfaction of volunteer's psychological gratification and mission accomplishment are also constantly changing. Therefore, considering matching preference information and satisfaction at two-sided match objects simultaneously is necessary to get reasonable target values of matching results for rescue tasks and volunteers.Originality/valueBased on the authors' novel EBRB method, a matching assessment model is constructed, with two-sided matching of volunteers to rescue tasks. This method will provide matching suggestions in the field of emergency dispatch and contribute to the assessment of emergency plans around the world.

Application of knowledge graph in power system fault diagnosis and disposal: A critical review and perspectives

Knowledge graph (KG) has good knowledge expression ability and interpretation, and its application to power system fault diagnosis and disposal can effectively integrate data of the whole life cycle of equipment and form a novel knowledge-driven operation and maintenance management mode. This is crucial to assist dispatchers in fault disposal and effectively improve the power system emergency handling capability and dispatch intelligence level. This paper conducts a systematic review and summary of the application of KG in power system fault diagnosis and disposal, so as to provide an adequate and comprehensive guide for further research in this field. Firstly, the definition, status, and classification of KGs are systematically described, and the general process of KG construction is sorted out. Secondly, the basic framework, construction process, key technologies, and typical practices of KG for power system fault diagnosis and disposal are summarized and reviewed in detail. Ultimately, several challenges, opportunities, and perspectives of KG in this field are carefully presented.

Robust Under-Frequency Load Shedding With Electric Vehicles Under Wind Power and Commute Uncertainties

Under-frequency load shedding (UFLS) is an important measure for tackling low-frequency events caused by load-generation imbalance. However, the uncertainty of wind power amplifies power imbalances and can potentially impair frequency stability. Electric vehicles (EVs) present a more effective means for addressing this issue compared to load shedding. However, EVs have several limitations such as commute randomness. To ensure frequency stability and simultaneously reduce load shedding, a bi-level confidence-interval-based optimal strategy is proposed to enable the participation of EVs in UFLS, where the uncertainties of wind power and the commute randomness of EVs are estimated using a non-parametric kernel density estimation (KDE) method. In bi-level optimization, the upper level reduces the dependency on commute randomness and the wind power uncertainty during load-shedding events. Further, the upper-level solutions are sent to EV charging stations for emergency dispatch. By contrast, at the lower level, an approximation-function-based priority is proposed to optimize the task allocation. Simulation results show the advantages of the proposed approach in maintaining a stable frequency compared with traditional and adaptive UFLS schemes.