Military Technical Academy Ferdinand I
Software application for simulation, analysis, evaluation and graphical representation of possible effects on buildings and people under blast in the urban space
1.Software module for defining the threat: Allows the user to define the threat by entering / selecting / calculating the following parameters:
- Type of bomb vehicle: Different categories of bomb vehicles are predefined. There is the possibility of defining a new one. The amounts of explosive were introduced according to ATF – Department of the Treasury Bureau of Alcohol, Tobacco and Firearms.
- Define the type of explosive: different types of bare explosive and explosive mixtures are predefined. There is a possibility of defining a new type of explosive;
- Definition of metallic casing: Depending on the type of bomb vehicle, the mass of the metallic casing is calculated.
Figure 1 Possibilities for defining the threat (bomb vehicle and explosive charge)
2.Software module for environmental blast characterization: performs the determination of parameters in the shock wave front and the reflected pressure and impulse depending on the threat set by the previous module and the stand-off distances. The mathematical models used to estimate the overpressure and impulse are based on the Rankine-Hugoniot and Kingery Bulmash equations. Also, complex algorithms are used to determine the visibility of the structures and building elements subjected to the direct shock wave.
The graphical representation of the overpressure on different buildings for the same bomb vehicle can be shown in the Figure 2.
Figure 2 Graphical representation of incident pressure on neighboring buildings by considering the structure elements visibility
3.Software application for structure characterization: performs the database with the characteristics of the analyzed structures. Depending on the data contained in the national regulations, the user has the possibility to select the characteristics of the buildings for which the behavior under blast loadings will be determined. There are predefined some features as followings: the type of building; year of construction; destination; class of importance; the geometry of the building; type of building materials used, Figure 3. The application provides the user with the ability to modify / define new data / features. Output data will be used by other applications to estimate the buildings level of damage and to assess the potential for the occurrence and propagation of the progressive collapse.
Figure 3 Building parameters for a reinforced concrete frame structure
4.Software application for the assessment of the level of damage of buildings and the occurrence of progressive collapse: performs a precise estimation of the effect of the blast on buildings and evaluates the potential for the occurrence and propagation of the progressive collapse. The application uses models with a single degree of freedom and P-I diagram to estimate the strength of the building elements under blast. Estimation is done on three levels of damage: 30%, 60% and 100%, figure 4. The level of 100% damage corresponds to the moment of element collapse.
Figure 4 The P-I diagram for reinforced concrete (RC) column evaluation under blast (left) and level of damages for RC frame structures under bomb vehicle (right)
5. Software application for the estimation of the effects of the shock wave against personnel
The effects of detonation of an explosive charge on personnel may be manifested by:
- the action of blast overpressure in time;
- the action of the fragments resulting from the destruction of structures or from the acceleration of objects;
- the impact of the human body driven by the explosion with different obstacles or with the surface of the ground.
Human injuries caused by explosive devices can be divided into main four categories, as follows:
- Primary lesions - due to exposure to excessive pressure, which is most likely to affect the organs in the chest and ears;
- Secondary injuries - due to the impact caused by fragments of the container in which the device is located or elements adjacent to the device, such as fragments from the buildings;
- Tertiary injuries - due to exposure to overpressure that throws the human body, causing cranial fractures and injuries to the entire body;
- Quaternary injuries - includes other methods of injury due to an explosion, for example burns, poisonings due to inhalation of explosive residues and psychological traumas.
This software application takes into account only the primary and secondary injuries. At the level of the head the area most sensitive to injury is the ear. In general, it is considered that the rupture of tympanic membranes takes place in the dynamic pressure range of 0.35 - 0.5 bar. A more precise approach to the effect of the shock wave on the head and ears should take into account not only the maximum value of the overpressure in front of the incident shock wave but also the duration of the positive or impulse phase. According to the AASTP-1 and taking into account characteristics of shock wave, the survival levels of 1%, 50 % and 99% for head and ears for a 450 kg TNT equivalent bomb vehicle can be shown in Figure 5.
Figure 5 Survival ranges for a 450 kg of TNT equivalent bomb vehicle to the head (left) and to the ears (right)
In the thoracic area, the area’s most susceptible to injury due to overpressure, are the zones of passage between environments with different densities. At an overpressure of more than 2.5 bar, potential fatal damage to the lungs and other organs that by their nature have spaces in which a fluid (fluid or gas), such as the stomach, intestines or bladder, can occur. In simple terms, it is enough to describe the lungs as crushed or exploded. To determine the survival ranges, Figure 6 for lung injuries under blast action there were used pressure – positive phase duration diagrams.
Figure 6 The survival distances for the effects of 450 TNT equivalent on lungs of an adult of 70 kg (left) and lungs of an adult of 70 kg in the lying position (right)
Using the same procedure it can be determined the ranges of survival for different amount of explosive charge and for different types of injuries.
SOFT GALAXY INTERNATIONAL SRL
Within the integrated applications related to the 9SOL project were developed.
The implementation architecture is presented in Figure 7.
Figure 7. 9SOL system architecture.
The hardware integrated system consists of the following components:
- Digital table model SensyTouch ST43SLIM - which has the role of displaying the processed data and performing calculations of medium complexity.
- The HPEProliant G10 model server, which serves the digital mass, having the role of performing complex calculations, being divided into virtual machines related to the developed software submodules.
- Server model TS TS431XeU-2G - dedicated to the private LTE communication system LTE - ALM17000.
- Router model RUTX09 - dedicated to the integration of mobile and radio link communications, including connection with other communication operators.
- DellPowerEdge R630 model server - dedicated to the operation of mobile communications applications and their integration with the command center.
MISSION PREPARATION MODULE (OFF-LINE)
The following functions have been implemented in this module:
- Explosion assessment
- Displaying the results of explosions on buildings
- Displaying the results of explosions on people
- Parameterization of a scenario - mission preparation
- Adding attributes for mission and agents
- Evaluation of the panic generator application - evacuation of the objective
Description: The integrated functionalities of the software applications will be used for the implementation of action scenarios and post-incident measures. In a first phase, the explosion simulation application will be used in an urban public space; the obtained results will be displayed on the GIS map, so that the effects of the explosions on the buildings and the people within the incidence can be visualized. Also, the mission preparation module will include: importing data and 2D and 3D geometric models from various sources and in different formats, the user will have the opportunity to make a number of settings and adjustments to ensure correct georeferencing. Users have the ability to use 3D modeling, the interface will have operating and navigation functions, with the ability to manually edit buildings and objects. The module for mission preparation is structured, on 3 levels: analyst-user, decision-maker-user and administrator.
Figure 8. Integrated control panel for 9SOL system.
Figure 9. Adding the necessary elements for mission planning.
MISSION CONDUCT (Real Time)
The following functions have been implemented in this module:
- Displaying the GPS position (location) for the agents in the objective
- Updating the GPS positions related to the agents
- Displaying physiological parameters for target agents
- Displaying video streams from monitoring video cameras
- Visualizing the mission in the VR field
Description: This module tests the capabilities of the 9SOL system for Command and Control of intervention teams, using the following capabilities: capturing and locating in the field of device elements and intervention teams by displaying location coordinates (GPS) in real time, with updated 5 seconds, capturing video streams from mobile operating sources, in the field, or taken from any sensors, aggregating them and operatively rebroadcasting video images to decision makers, the ability to access existing video sources and initialized operational video sources during missions. The application allows the storage of these video streams and the possibility of displaying (on request) them on the digital table, the application will allow the interconnection and data transmission between all entities participating in the action and the command center, to provide real-time operational situation to all actors involved, by using the mobile terminals equipped with agents, integrating the remote monitoring of the physiological parameters of the intervention teams so that the physiological parameters are displayed in real time in the command center, so that the mission leader can decide to withdraw some agents or supplement the staff from the field.
Figure 10. The final representation of a scenario.
Figure 11. Real-time addition of video and communications components.
MISSION CONDUCT - Communications (Real Time)
The following functions have been implemented in this module:
- Carrying out the messaging communication between the agents and the command center
- Realizing the audio communication between the agents and the command center
- Changing text and image files between agents and the command center
Description: This module tests the communication capabilities between field agents and the operational decision-making center. The applications will use the private communication system (closed circuit) LTE - ALM17000 and the CALM application that provides services between the LTE mobile terminals and the control center within the private network. The Linphone application, in the form of a soft phone, installed on the laptop near the access gate to the test location, as well as on phones in the mobile control center, which have Wi-Fi access, will also be tested. Scenario 3 will test the possibility of integrating on the private communications system, intervention teams that are not in the coverage area of the private network LTE - ALM17000, by interconnecting this private network with mobile telephony operators, thus resulting in the possibility of extension of the operative communications service. Last but not least, a text messaging application based on the blockchain structure will be tested, which ensures the exchange of text messages and the transmission of operative information such as images.
Figure 12. Communications dispatcher interface.
MARCTEL SIT Srl.
A communication system developed around on a deployable private LTE network
1.A description of the communication subsystem solution
The communications subsystem block diagram is depicted in the Figure 13.
We chose to use a private LTE network due to the following considerations:
- the commercial LTE operators might be affected in a crisis scenario, either because they are prone to be heavily requested by the other users (denial of service risk) or their infrastructure (eNodeB’s) is affected.
- a rather large area must be covered (e.g., 300 x 300 m). A Wi-Fi alternative has a lesser coverage (or requires more access points) and the communication bands are not guaranteed to be available when needed.
- a large band is required, mainly for video streaming. LTE has a high performance regarding the efficiency of band usage (bits/Hz/s) and the necessary UE’s (user equipment) are well tested and tried due to mass dissemination for commercial purposes.
- LTE provides the IP connectivity over which it’s easy to seamlessly implement various communication functions: audio/video streaming, file transfer, encryption, tunneling.
- the UE costs (smart phones, LTE routers) are very competitive, compared to other, smaller scale production alternatives.
- there’s a consensus within the European Union that the 1stresponders’ organizations need to be given dedicated (LTE) radio spectrum for their actions. Compared to relying on unlicensed frequencies, these organizations will benefit from complete availability for the dedicated band, less noise, better voice and image quality.
- smart phones are small and deliver excellent audio/video capabilities.
Figure 13. Communications and physiological data collection subsystems
The communication network, apart from the LTE part, includes conventional IP phones (or desktop soft phone applications), inside the mobile data centre, a simple backhaul based on radio relays/satellite links/government-owned networks (or a combination of these) and a number of IP phones in the main command centre. Also, gateways for commercial LTE operators are included: if any users are outside the LTE coverage, they can communicate via a commercial operator network (if available).
The calls are handled by SIP server applications (and SIP clients installed on the phones) and machines, one within the mobile centre and another one in the main centre.
Group calls are supported; the groups can be configured in advance, with management tools provided in the SIP apps. The audio and video streams pertaining to the one-on-one and group calls are stored in the mobile centre; they are available for processing in the main centre, because the IP network easily supports transfers.
The communications system doesn’t use any outside-managed resources, like the Internet. This makes any outside attacks less plausible and possible. Additional security is provided if IPSec servers and client applications are implemented.
2. A description of the private LTE network
There are various manufacturers for small scale LTE networks, for various purposes. For instance, there are solutions that are integrated in larger commercial networks and have limited capabilities if the backhaul to the main infrastructure is unavailable.
There are certain characteristics that helped us in choosing a convenient solution:
- at any given time, the active users’ number is small enough, about 30.
- the covered area allows implementing a single LTE cell. However, the system can be expanded, if needed. For the time being, we don’t need to use the hand-over functions of the network
- the necessary eNodeB is small enough and has reasonable power consumption. It can be hoisted, together with the antenna(s) on a telescopic pole a few meters long, which can be installed where the mobile command centre is situated in less than 30 minutes. There are available solutions that gather in unique equipment the eNodeB and the evolved packet core (EPC) functionalities.
- the necessary transmission power is 5...10 W, with a good quality, high gain antenna system
- no billing is required.
A critical demand for the private LTE network is to operate in band 28 (according to the requirements imposed by ANCOM for PPDR / “first responders” applications) and, if possible, in band 68 LTE. The equipment we selected, which combines the functions of ePC and eNodeB, is ALM17000, produced by Atos (France). The bandwidth used is selectable, including 2x3 MHz (as required by ANCOM), 2x5 MHz, 2x10 MHz, etc. Any LTE smart phone with Android OS and operating in the 28 band is suitable. We use CAT S61, a ruggedized phone that has additional facilities compared to other types and that allow further developments (thermal video camera, air quality sensor –able to sense particles that may occur in case of explosions). The smart phones and the routers within the private LTE network have dedicated SIM cards; when turning on the equipment, registration occurs, just as in any LTE network, and IP addresses are given. There is a dedicated software app that runs on Android OS’s installed on the phones; it gives the user only the functionalities that are necessary during the mission:
- one to one call
- one-touch attachment to a group call
- video streaming upload (from the phone’s back camera) is done when the user pushes a dedicated button (“push to video”). A “push to talk” function is unnecessary, as full audio conferences are available without restrictions of bandwidth
- file upload
- SMS send
- user notification when a SMS or file is received
A Quality of Service (QoS) system is used to give priority to streaming-type connections
The LTE user equipments also include LTE routers, for uploading video streams from fixed position surveillance cameras. We have selected LTE routers manufactured by Teltonika (Lithuania). RUTX09 and RUTX11 are study; they work in band 28 LTE and are providing a large throughput on the LTE side, appropriate for video streaming. They also provide tunneling server/client options, plus a local Wi-Fi (RUTX11), useful if a mobile unit with some subscribers located works in a remote place, outside the pLTE that serves the mobile centre. A tunnel – carried by a commercial LTE operator- is established between a RUTX11 router in the remote unit and a RUT09 attached to the mobile centre, which provides connectivity to the said centre’s local network; the remote subscribers have the same available video and voice services, via local Wi-Fi, as those in the pLTE network, and a dashcam connected to the RUTX11can upload a video stream, just like the other surveillance cameras.
The physiological data collection module
We have decided to split the physiological data collection task into two separate scenarios:
While in training sessions, with intense physical effort, significant indicators are recorded: pulse, burnt calories, covered distance, ECG. For this we use Polar A370 watches, as these contain the appropriate sensors and are able to communicate via Bluetooth with a smart phone. A specialized app, that accompanies the sensors, is recording the data. After the session is finished, the data are transferred by another ready-made application to a server that sorts and stores the data for each of the subjects, for further analysis.
2.Monitoring during actual missions
The data most necessary during missions are tied to the subject’s capability to function, a “man-down warning” for the supervisors in the mobile and main centers. The physiological sensors must be accurate and, at the same time, to be easy to wear for the subject.
During the project’s previous phases, we opted for a LoRaWAN-based communication between dedicated physiological data gathering devices and a gateway placed in the mobile centre. The cardiological data were provided by Polar H10 belts on an analogical radio carrier; the custom device also contained a GPS receiver and a 3D accelerometer; the latter being used for the “man-down” function.
Afterwards, we found out that Polar had developed an API (application programming interface) that allowed real-time data to be retrieved from the Polar H10 sensor, on Bluetooth support, by an application developed by us. The H10 sensor also includes a 3D accelerometer and, in addition to the heart rate value, also provides data on the variability of this rhythm and even the possibility of performing an electrocardiogram. This data is taken over by our application. The acquisition of EKG data can be triggered, and we can present it graphically. Of course, such a session is started/stopped at the request of the operator monitoring the biometric information collection system, because the data volume is substantial, and the EKG is only sporadically necessary.
We are collecting and storing Heart Rate Variability (HRV) from the Polar H10. Their importance lies in further interpretation for assessing the physical stress of the fighter, with specialized apps, under the supervision of medical trained specialists; this is beyond the scope of the 9SOL project. For a HRV presentation, see: Fred Shaffer and J. P. Ginsberg: An Overview of Heart Rate Variability Metrics and Norms, in Frontiers in Public Health, published on September 28, 2017, as well as other publications in the field.
Some ideas about HRV: at physical or mental stress (stress, strong emotions), the pulse increases and HRV decreases. Also, for a subject who has exerted intense (possibly excessive) physical effort, HRV decreases. The return of HRV values to higher levels indicates the body's recovery; on the contrary, the lack of this evolution is an alarm signal. Not only physical demands have this effect: in individuals with post-traumatic stress disorder (PTSD), HRV, especially with higher frequency variations of the measure over time (RR), decrease; slow, low frequency variations remain.