Emergency Communication Services Research Articles

Two-layer intelligent deployment of capsule airports and unmanned aerial vehicles for providing emergency communication services

The utilization of Unmanned Aerial Vehicles (UAVs) as base stations for emergency communication services has garnered significant attention due to their lightness and agility. To increase the capacity and coverage of UAVs, the Capsule Airport (CA) is developed, which serves as a recharging and retrieval station for UAVs. Meanwhile, deploying CAs and UAVs in appropriate positions is crucial for ensuring high-quality and efficient service provision. To address this challenge, we propose the Two-Layer Maximum Deployment Problem for Capsule Airports and Unmanned Aerial Vehicles (2L-MCDP-C&U). The objective of the 2L-MCDP-C&U is to maximize the number of served users by determining the ground locations for opening a given number of CAs and deploying their UAVs in 3D space, while considering the connectivity of UAV-to-UAV, UAV-to-CA, and UAV-to-user. An improved variable neighborhood search algorithm is designed based on the k-means (VNS-K) to solve the 2L-MCDP-C&U. To further validate its efficacy, we conduct experiments on random instances of various sizes and a practical case study of Zhulin town in China. Our work paves the way for more efficient and effective emergency communication services using CAs and UAVs.

Enhanced Max-Min Rate of Users in UAV-Assisted Emergency Networks Using Reinforcement Learning

Unmanned aerial vehicles (UAVs) as an Aerial Base Station (ABS) are the enabler in the provisioning of emergency communication services. However, ABS unplanned deployment creates interference from the neighboring co-channel base station, which hinders meeting the required quality-of-service (QoS) requirements and the minimum rate of users. Hence, the ABS deployment and its power allocation require a machine learning-based solution xthat can plan in real-time to enhance the users’ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max-min sum-rate</i> . We propose the reinforcement learning-based <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> greedy algorithm to solve the max-min optimization problem. The simulation results validate the proposal by achieving around 2.3 bps/Hz high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">minimum sum-rate</i> compared to the conventional water filling algorithm at the same ABS altitude.

A Dynamic Task Scheduling Method for Multiple UAVs Based on Contract Net Protocol.

Unmanned aerial vehicles are becoming promising platforms for disaster relief, such as providing emergency communication services in wireless sensor networks, delivering some living supplies, and mapping for disaster recovery. Dynamic task scheduling plays a very critical role in coping with emergent tasks. To solve the multi-UAV dynamic task scheduling, this paper constructs a multi-constraint mathematical model for multi-UAV dynamic task scheduling, involving task demands and platform capabilities. Three objectives are considered, which are to maximize the total profit of scheduled tasks, to minimize the time consumption, and to balance the number of scheduled tasks for multiple UAVs. The multi-objective problem is converted into single-objective optimization via the weighted sum method. Then, a novel dynamic task scheduling method based on a hybrid contract net protocol is proposed, including a buy-sell contract, swap contract, and replacement contract. Finally, extensive simulations are conducted under three scenarios with emergency tasks, pop-up obstacles, and platform failure to verify the superiority of the proposed method.

Aiding a Disaster Spot via Multi-UAV-Based IoT Networks: Energy and Mission Completion Time-Aware Trajectory Optimization

Unmanned aerial vehicles (UAVs) are one of the effective means to provide emergency communication services in post-disaster areas. In this article, we consider data dissemination in post-disaster areas, where all Internet of Things (IoT) nodes may not have data needs all the time. The energy consumption in data dissemination is one of the key metrics to pay attention to since the charging facilities for UAVs may be limited due to the destruction of existing infrastructure. In addition, UAVs have limited endurance or lifetime, so unnecessarily flying over IoT nodes that may not have data is time consuming. Therefore, given the energy budget and data requirements of the IoT nodes, we formulated a data dissemination problem using multiple UAVs in a post-disaster area while optimizing their trajectory, mission completion time, and energy consumption. After time discretization, the formulated problem is a mixed-integer nonconvex problem and thus difficult to solve in general. For this reason, we jointly use the bisection search technique and the block coordinate descent (BCD) method to solve the entire problem while aiming to optimize the trajectory and mission completion time of the considered UAV as well as the overall energy consumption. In each iteration of the BCD method, we solve the user association, trajectory optimization, and power optimization subproblems one after the other in an alternating fashion. To solve each subproblem, we employ the geometric programming (GP)-based optimization technique that transforms the variables and constraints. Regarding the initial trajectory of the UAV, we utilized dynamic programming techniques based on unsaturated data requirements of IoT nodes. We performed extensive simulations in many realistic environments to verify the effectiveness and efficiency of the proposed data dissemination scheme in post-disaster scenarios.

Optimal Throughput for Multicast over MANET-Satellite Networks

The convergence of MANET and satellite networks has been considered as one of the potential solutions to provide emergency communication and disaster relief services. However, unreliable MANET and satellite links may influence seriously to data transmission. In this paper, we study the application of packet-level coding for enhancing network throughput for multicast services over integrated MANET-satellite networks. First, we characterize the performance of multicast networks in terms of the probability of packet delivery under different packet-level codes. We then formulate and solve the coding optimization problem for typical values of computational resources at the network nodes given some target probability of successful delivery to the receivers. Finally, several simulation results show significant gains in the average achievable rate at the receivers with respect to routing for representative scenarios with different types of network devices given a strictly-high probability of successful delivery of the multicast networks. Furthermore, the devices with higher computational resources can obtain significantly better throughput gain.

Emergency response, intervention, and societal recovery in Greece and Turkey after the 30th October 2020, MW = 7.0, Samos (Aegean Sea) earthquake.

On 30 October 2020, an Mw = 7.0 earthquake struck the Eastern Aegean Sea with considerable impact on Samos Island in Greece and the area of Izmir in Turkey. It was the most lethal seismic event in 2020 worldwide, and the largest and most destructive in the Aegean Sea since the 1955 earthquake that also affected both countries. The Civil Protection authorities in Greece and Turkey were effectively mobilized responding to the earthquake emergency. The main response actions comprised initial announcements of the earthquake and first assessment of the impact, provision of civil protection guidelines through emergency communication services, search and rescue operations,medical care, set up of emergency shelters and provisions of essential supplies, psychological support, as well as education, training activities and financial support to the affected population. From the comparison of the Civil Protection framework and the implemented response actions, it is seen that actions at both sides of the eastern Aegean Sea, followed a single-hazard approach in disaster management with similar response activities coordinated by a main Civil Protection agency, which was in close cooperation with the respective authorities at a national, regional and local level. Based on the presented information, it is concluded that the post-earthquake response and emergency management were satisfactory in both countries, with valuable lessons learnt ahead of the next major earthquake. To this end, many aspects can be further addressed to enhance community resilience and introduce a multi-hazard approach in (natural and man-made) disaster management.

Metaheuristic‐based optimal 3D positioning of UAVs forming aerial mesh network to provide emergency communication services

The optimal placement of unmanned aerial vehicles (UAVs) to facilitate post-disaster emergency communication services is a paramount research domain. The novelty of the authors’ work is to optimally place available UAVs in 3D space to meet the objectives prominent during such situations. The objectives considered here are target coverage, QoS, energy consumption and two newly characterized objectives, i.e. equal load distribution over UAVs and fault tolerance for improving network connectivity and lifetime. To improve these conflicting objectives altogether, the authors proposed two metaheuristic-based hybrid optimization algorithms, namely, HWWO-HSA, a hybrid of Water Wave Optimization (WWO), Harmony Search (HS) and Simulated Annealing (SA); and HGA-SA, a hybrid of Genetic Algorithm (GA) and SA. Furthermore, to improve network performance, the authors performed their parameter tuning using well-known Taguchi's design of experiment. For maintaining network connectivity, the authors used the concept of graphs for connected components. The proposed hybrids are compared with their originals, i.e. GA, HS, SA and WWO over different scaled test scenarios. The non-parametric Kruskal–Wallis test and Dunn's post hoc test suggest that hybrids perform better than the originals. HGA-SA significantly outperforms in small-scale scenarios while HWWO-HSA significantly outperforms in medium-scale and large-scale scenarios. However, being hybrid the computational time of the hybrids is greater than the originals.

Optimal Placement of Low-Altitude Aerial Base Station for Securing Communications

Because of its cost-effective and on-demand deployment, low-altitude aerial base stations (BSs) are capable of providing emergency communication services in many scenarios. This letter investigates the security issue in emergency communications where the aerial BS is deployed optimally to serve ground users in the presence of an eavesdropper. We aim to maximize the probability of non-zero secrecy capacity to improve the possibility of physical-layer security transmission via the optimal placement of the aerial BS. The resulting nonconvex optimization problem will be simplified based on its geometric properties and equivalent transformation. The simplified problem will then be solved by using semidefinite relaxation. Numerical results show that the optimal placement of the aerial BS can significantly improve the probability of non-zero secrecy capacity.

Tethered Balloon Technology in Design Solutions for Rescue and Relief Team Emergency Communication Services.

The actions taken at the initial times of a disaster are critical. Catastrophe occurs because of terrorist acts or natural hazards which have the potential to disrupt the infrastructure of wireless communication networks. Therefore, essential emergency functions such as search, rescue, and recovery operations during a catastrophic event will be disabled. We propose tethered balloon technology to provide efficient emergency communication services and reduce casualty mortality and morbidity for disaster recovery. The tethered balloon is an actively developed research area and a simple solution to support the performance, facilities, and services of emergency medical communication. The most critical requirement for rescue and relief teams is having a higher quality of communication services which enables them to save people's lives. Using our proposed technology, it has been reported that the performance of rescue and relief teams significantly improved. OPNET Modeler 14.5 is used for a network simulated with the help of ad hoc tools (Disaster Med Public Health Preparedness. 2019;13:203-210).

PS-CARA: Context-Aware Resource Allocation Scheme for Mobile Public Safety Networks.

The fifth-generation (5G) communications systems are expecting to support users with diverse quality-of-service (QoS) requirements. Beside these requirements, the task with utmost importance is to support the emergency communication services during natural or man-made disasters. Most of the conventional base stations are not properly functional during a disaster situation, so deployment of emergency base stations such as mobile personal cell (mPC) is crucial. An mPC having moving capability can move in the disaster area to provide emergency communication services. However, mPC deployment causes severe co-channel interference to the users in its vicinity. The problem in the existing resource allocation schemes is its support for static environment, that does not fit well for mPC. So, a resource allocation scheme for mPC users is desired that can dynamically allocate resources based on users’ location and its connection establishment priority. In this paper, we propose a public safety users priority-based context-aware resource allocation (PS-CARA) scheme for users sum-rate maximization in disaster environment. Simulations results demonstrate that the proposed PS-CARA scheme can increase the user average and edge rate around 10.3% and 32.8% , respectively because of context information availability and by prioritizing the public safety users. The simulation results ensure that call blocking probability is also reduced considerably under the PS-CARA scheme.

EMERGENCY COMMUNICATIONS NETWORK FOR DISASTERS MANAGEMENT IN VENEZUELA

Abstract. The integration and use of different space technology applications for disasters management, play an important role at the time of prevents the causes and mitigates the effects of the natural disasters. Nevertheless, the space technology counts with the appropriate technological resources to provide the accurate and timely information required to support in the decision making in case of disasters. Considering the aforementioned aspects, in this research is presented the design and implementation of an Emergency Communications Network for Disasters Management in Venezuela. Network based on the design of a topology that integrates the satellites platforms in orbit operation under administration of Venezuelan state, such as: the communications satellite VENESAT-1 and the remote sensing satellites VRSS-1 and VRSS-2; as well as their ground stations with the aim to implement an emergency communications network to be activated in case of disasters which affect the public and private communications infrastructures in Venezuela. In this regard, to design the network several technical and operational specifications were formulated, between them: Emergency Strategies to Maneuver the VRSS-1 and VRSS-2 satellites for optimal images capture and processing, characterization of the VENESAT-1 transponders and radiofrequencies for emergency communications services, technologies solutions formulation and communications links design for disaster management. As result, the emergency network designed allows to put in practice diverse communications technologies solutions and different scheme or media for images exchange between the areas affected for disasters and the entities involved in the disasters management tasks, providing useful data for emergency response and infrastructures recovery.

BeiDou integrated disaster reduction application platform

To better improve the emergency communication and location-based services of disaster information reporting network for serious natural disaster emergency response and relief, the national natural disaster reduction application platform based on BeiDou navigation satellite system is constructed. The administrative distributed platform is integrated with BeiDou positioning and multiple communication ways so as to achieve main disaster reduction application services, including disaster information acquisition and monitoring, emergency relief for trapped people, on-site emergency relief command service, relief supplies’ transportation monitoring, and disaster information publishing service. By the platform, serious disaster information reporting time may be reduced to one hour and the emergency decision-making information service for serious natural disasters can be effectively improved, and it will be helpful to provide technical references for the industrial application and promotion of BeiDou integrated disaster reduction.

Emergency satellite communications: research and standardization activities

Space communications is an ideal candidate to handle critical and emergency situations arising on a regional to global scale, provided there is effective integration among them. The article presents a review of solutions offered by space communication systems for early warning and emergency communication services. It includes an up-to-date review of public research and standardization activity in the field, with a specific focus on mass alert. The main technical issues and challenges are also discussed along with the cutting-edge research from the scientific community.

Call Centres As Sites of Professional Practice: “Where Old Social Workers Go to Die”?

The use of call centre operations in public and private sectors is a notable development in the changing structure and nature of employment worldwide. This trend is clearly evident in the South Pacific with the establishment of a call centre as the official point of entry for the statutory child protection systems in both New Zealand and New South Wales. As sites of professional practice however call centres are a controversial development. This paper discusses the practice findings of a qualitative research project which explored the particularity of intake social work (ISW) with 14 social workers employed at the Child Youth and Families' (CYF) National Contact Centre (NCC) in New Zealand. Findings were established through semi structured interviews and thematic analysis. They reveal a unique practice combining attributes of social work and emergency communication services in a workplace environment subject to similar output requirements as those found in commercial call centres.

IEEE Standards Supporting Cognitive Radio and Networks, Dynamic Spectrum Access, and Coexistence

Cognitive radio techniques are being applied to many different communications systems. They hold promise for increasing utilization of radio frequencies that are underutilized today, allowing for improved commercial data services, and allowing for new emergency and military communications services. For example, these techniques are being considered by the U.S. FCC for communications services in unlicensed VHF and UHF TV bands. Although traditionally these techniques are closely associated with software-defined radios, many standards such as WiFi (IEEE 802.11), Zigbee (IEEE 802.15.4), and WiMAX (IEEE 802.16) already include some degree of CR technology today. Further advances are occurring rapidly. IEEE 802.22 will be the first cognitive radio-based international standard with tangible frequency bands for its operation. Standardization is at the core of the current and future success of cognitive radio. Industry stakeholders are participating in international standards activities governing the use of cognitive radio techniques for dynamic spectrum access and coexistence, next-generation radio and spectrum management, and interoperability in infrastructure-less wireless networks. This article provides a review of standardization activities for cognitive radio technologies and comments on prospects and issues for future standardization.

An Organized Approach to Trauma Care: Legacy of R Adams Cowley

The organized approach to caring for trauma patients was introduced into the civilian setting by the innovative pioneer, R Adams Cowley. His system in Maryland has the following 11 components: (1) a State Police Aviation Division that transports patients throughout the State; (2) trained paramedics at the scene of the accident as well as on the helicopter, who will stabilize the patients en route to the Shock Trauma Center; (3) one central dispatch communication center in Baltimore that coordinates information between paramedics and the Trauma Center; (4) a Shock Trauma Center with a helicopter landing zone near the building; (5) trained trauma nurses and trauma technicians to transfer the patient from the helicopter by stretcher to the resuscitation area; if there is a special complication, such as an airway problem, the anesthesiologist and or trauma surgeon may meet the helicopter on the roof as well; (6) trauma surgeons, board-certified in surgery, with a certificate of added qualification in surgical critical care, to treat the critically ill trauma patients in the resuscitation area; (7) a CT scan and portable X-ray units in the admission area that aid in the diagnosis of the injury; (8) operating rooms adjacent to the admission area for repair of trauma injuries; (9) a surgical intensive unit to care for the trauma patient; (10) a team of specialty physicians trained in a wide variety of specialties who work as a multidisciplinary unit caring for the hospitalized patient; and (11) an ambulatory outpatient unit that allows the patient to be followed in the center after discharge. Dr. R Adams Cowley incorporated each of these 11 components for an organized trauma center into Maryland. In recognition of his landmark contributions to trauma, the eight-story Shock Trauma Center was named the R Adams Cowley Shock Trauma Center. There is growing evidence that this organized system in trauma care seen in Maryland must be replicated in every state in our nation. The results of the Health Resources and Services Administration Report in 2002 show serious limitations in our nation's organized approach to emergency and trauma care. This report indicates that many Americans do not have access to well-trained pre-hospital emergency personnel. Between 10 and 15% of the US population does not have access to basic emergency medical and communication services. Moreover, the presence of key trauma system components continues to vary throughout the country, most likely because of growing economic constraints. Emergency communication systems remain fragmented, and adequate training programs and protective equipment for health personnel remains notably absent. The threat of inadequate funding for the state manifests itself in the consistent uneasiness regarding the recruitment and continued retention of trauma care providers. Federal authorities must devise national emergency medical and organized trauma programs to save the lives of injured Americans.

Adjacent-Cell Interference in Direct-Sequence CDMA Forward Traffic Channels

Each transmission from a base station in a mobile cellular direct-sequence CDMA network is a source of interference for the receivers in the mobile handsets that are operating in adjacent cells. This interference can limit the capacity of the forward traffic channels. The effect of adjacent-cell interference on the performance of the handset receivers is evaluated for a mobile cellular CDMA network that employs quadriphase-shift-key spreading, convolutional coding, and soft-decision decoding. It is demonstrated that acceptable performance may not be possible for a fully loaded cellular network. Of particular interest in this paper are cellular networks in which the base stations are mobile and must be interconnected by wireless communication links. Such networks are important for military applications and certain civilian emergency communications services.