Dispersal Device Research Articles

Covert system for detecting nuclear dirty bombs in public venues

Background In the past two decades, the potential threat of a radiological dispersal device (RDD) or “dirty bomb,” which combines conventional explosives with radioactive material, has been a concern for counterterrorism efforts. The accessibility of radioactive materials used in various applications, such as medicine, industry, and research, makes RDDs a viable weapon of choice for terrorists. While the radiation released from an RDD is generally not lethal beyond a short range, the long-term health, environmental, and psychological effects of radiation release will have an impact on the future of a society. Providing proactive security measures will aid in the deterrence of potential radiological terrorist threats. Methods The use of commercial off-the-shelf detectors and GPS modules can be integrated with software to provide the approximate location of a radioactive anomaly. With the strategic placement of a circular array of 4-inch × 4-inch Thallium dopped Sodium-Iodide (NaI) in a façade of a full trashcan, it is possible to determine if, when, and the general direction of a hand- carried threat entering a venue. A supplemental detector containing a Cesium-Iodide (CsI) crystal and a GPS module fitted to a plate carrier vest can further refine the location of a threat. In tandem, these two designs are capable of providing the RDD screening that is currently lacking in public. Conclusions While a true threat may contain a radiation source well in the hundreds of Curies, the designs selected are tested and calibrated to 1-microcurie button sources. Which provides scaled results that indicate the possibility for the deployment of such a detection scheme in a venue. Although the devices tested are limited by commercial GPS resolution, the ability for both designs to determine the presence and approximate location of a button source within 10 feet is promising for further larger scale tests.

Radiological risk and legal issues analysis for Terrorism attack scenario Using Radiological Dispersion Devices.

Radiological risk and legal issues analysis for Terrorism attack scenario Using Radiological Dispersion Devices.

Clinical observation of wild animals near the CRAS lake (Mato Grosso do Sul, Brazil) submitted to homeopathic treatment by a slow dispersion device: a possible indication of environmental balance.

Abstract The environmental imbalance in all its parts (land, plant, animal, man) is one of the most significant challenges of modern times due to the difficulty of a comprehensive, effective, and non-aggressive corrective approach. Due to its biophysical qualities, water seems able to propagate physicochemical signals capable of producing effects on living systems, as recently demonstrated by the method of solvatochromic dyes. For this reason, a slow dispersion device containing a solid base soaked in a homeopathic ingredient was developed to treat animals living in defined ecosystems. This work aimed to evaluate the behavior and clinical status of tapirs (Tapirus terrestris) and capybaras (Hydrochoerus hydrochaeris) that inhabit the neighborhood of a lake subjected to the device's action as indicators of a possible balance of the entire system. The area under study was CRAS (Center for the Recovery of Wild Animals), inserted in an urban forest in Campo Grande - MS, Brazil. The anamnesis carried out with the park managers revealed the occurrence of attacks and mutilations among the animals due to stress and the vast infestation of ticks (Amblyomma cajennense) in wild mammals and their larvae in humans that visited the trails, which caused the closure of the park for school excursions given the risk of spreading zoonoses. The device contained a solid base of hydrocolloid and calcium carbonate soaked in a homeopathic formulation containing Chamomilla 12 cH, Artemisia absinthium 12 cH, Calcarea carbonica 30 cH, Psorinum 12 cH, Sulphur 12 cH, Artemisia lerchiana 12 cH, and Apis mellifica 12 cH, indicated for the treatment of animals whose signs of stress are an increase in ectoparasites and misbehavior. The devices were installed at three points: at the source, 500 meters away from the lake, at the watercourse, 200 meters from the lake, and at the lake itself on 10/08/2021, repeating the placement on 12/10/2021. The animals observed were four tapirs and three capybaras. Fifteen days after the date of the 1st placement of the devices, the manifestation of natural animal behavior was observed, such as teaching puppies to swim, indicating well-being. Twenty days after installation, a gradual decrease in teleogynes (adult forms) and larvae was observed, with the disappearance of ticks in all animals after six months of the device installation without chemical intervention to control the parasites. Park employees who frequent the trails and surroundings report that they have not suffered any more attacks from larvae (so-called “micuins”), even in times of greater occurrence, such as the dry seasons. Thus, it is suggested that installing slow dispersion devices in natural springs, dams, and lakes could be used as a resource for ecological balance, and the clinical observation of resident animals could be a possible indicator of environmental recovery. More studies using this approach are needed to consolidate these findings. Keywords: Homeopathic complexes, ecosystems, environmental homeopathy.

Recovery of fire-damaged “cerrado” area treated with homeopathic preparations in slow dispersion devices – a descriptive study.

Given the seasonal climatic characteristics, forest fires in “cerrado” areas in Central Brazil are common and challenging to prevent. Despite fire being a plant stimulation factor, such as breaking seed dormancy, when it covers large areas or occurs very frequently, it can cause irreparable damage to nature. Prevention is difficult and costly, and there are no corrective action options other than waiting for natural regeneration, which is usually slow and, not infrequently, with permanent damage. Due to its physicochemical qualities acting in biological regulation processes, water has been considered the primary vehicle for propagating signals from homeopathic ingredients, as suggested by previous studies carried out with solvatochromic dyes. Therefore, such inputs could, in theory, be inserted into watercourses to stimulate the regeneration of the biome destroyed by fire. This hypothesis motivated this case study. A slow dispersion device was developed aiming at promoting continuous environmental regeneration, containing hydrocolloid and calcium carbonate as a solid base soaked in a homeopathic complex specifically designed for this purpose, composed of Arsenicum album, Arnica montana, Staphysagria, Ignatia amara, and Phosphorus, all at 30cH. The case occurred in Nascentes do Rio Taquari Park, between Mato Grosso and Mato Grosso do Sul state, Brazil. It is a “cerrado” area, with multiple springs that feed the Paraguay River, occupying an area of 26,849 hectares over the Guarani and Bauru aquifers. After the fire in early September 2020, the devices were fixed at 9 strategic points in the park (P1 to P9) over 10 days, between September 29, and October 11, 2020, in water courses close to the main springs. To assess the restoration signs of the post-fire environment, the technicians responsible for monitoring the park made observations of flora and fauna recomposition in different locations close to four device-insertion points (P3, P5, P7, P8). Signs of recovery were observed 40 days after the fire was over. A rapid pioneer plant restructuring was noted, with a significant regrowth of grass, herbaceous and shrub species, such as Mutamba (Guazuma ulmifolia), Murici (Byrsonima spp.), Inga (Inga sp.), Brachiaria (Brachiaria sp.), Jaraguá grass (Hyparrhenia rufa), Colonião grass (Panicum maximum), Gabiroba (Campomanesia sp.), and Pixirica (Miconia sp.). Some species, such as Mimosa (Mimosa sp.), Colonião grass (Panicum maximum), and Jaraguá grass (Hyparrhenia rufa), were not detected in the area before the fire, probably by the seed bank stimulation caused by the heat. There was rapid forest regeneration (4 months after the fire) and restoration of most of the burned trees, both for resisting the fire and for being free of invasive species highly aggressive to native plants, which were controlled by the action of fire. Concerning the fauna, a vast animal population was detected, especially birds, highlighting the “Tuiuiú” (Jabiru mycteria) and “Socó” (Tigrisoma lineatum) close to a water body with a waterfall area (P3). Both species belong to the “Pantanal” biome close to the park. Such species began to frequent the park's lakes, being observed until February 2023 (the last survey date). The park's inventory of lichens and fungi showed an unusual tolerance to fire in species that adhered to burned trees and remained active. In this way, it is suggested that installing slow dispersion devices in watercourses can contribute to the regeneration of other “cerrado” biome areas subjected to fire, protecting the local biodiversity. More studies of this nature are needed to know the real impact of this method on the recovery of different biomes.

Оценка метода профилактики девиации ирригационного потока при факоэмульсификации с использованием дисперсивного вискоэластика (Вискоблок) в аспекте состояния витреолентикулярного интерфейса

Purpose. Evaluate state of the vitreolenticular interface before surgery, during phacoemulsification of cataract, and in the early postoperative period. To assess the effectiveness of «Viscoblock» method application during phacoemulsification to prevent intraoperative irrigation fluid misdirection syndrome by blocking the penetration of irrigation fluid through the zonular fibers through injecting dispersive ophthalmic viscosurgical device behind the iris. Material and methods. We operated 49 patients (50 eyes) diagnosed with age-related cataracts. All patients were divided into two groups. In the first group, we performed phacoemulsification with hydrophobic intraocular lens (IOL) implantation and application of the «Viscoblock» method. This group included 24 patients. In the second group, we performed phacoemulsification with hydrophobic IOL implantation using standard technique, it included 25 patients. All patients underwent standard ophthalmological examination and specific additional ones: ultrasound biomicroscopy – UBM Aviso (Quantel Medical, France); spectral optical coherence tomography OCT (Solix, Optovue, USA). Surgical treatment was performed under the control of an operating microscope equipped with intraoperative OCT (Lumera Rescan 700, Carl Zeiss, Germany). Results. According to preoperative diagnostics and it's UBM data, all patients in the first and second groups showed abnormalities in lens zonular fibers. According to OCT data before the surgery, no cases of anterior hyaloid membrane (AHM) detachment were detected. During the surgery, AHM detachment was observed in 24% of cases in first group and in 56% of cases in second group. Intraoperative iris prolapses occurred in 8% of cases only in the first group. Posterior capsule rupture was observed in only 1 patient in second group. Conclusion. Our technique, «Viscoblock», allows us to limit the penetration of irrigation fluid through the Zonula ciliaris in 76% of cases. However, it should be noted that the method does not provide complete prevention of AHM detachment, as it may already exist in some patients. Additionally, we cannot exclude partial washout of viscoelastic substance during the surgery, which can reduce the tamponade effect. Key words: vitreo-lenticular interface, Berger's space, intraoperative fluid misdirection syndrome, optical coherence tomography, ultrasound biomicroscopy, «Viscoblock», cataract, lens zonular fibers, vitreous body, posterior lens capsule, anterior hyaloid membrane, intraocular lens

О применимости визуализации на сфере Пуанкаре для анализа колебательных процессов в фотохимических и фотоэлектрохимических системах, включая фотоиндуцированные процессы в полупроводниках

The use of visualization on the Poincaré sphere for the analysis of self-organization in semiconductors is quite exotic, however, it does not have physical reasons that would make it impossible to implement this approach. We propose to use the Poincaré sphere visualization method to analyze fluctuations and oscillations in the experimentally measurable concentrations of different ions in self-organizing media, including semiconductors and their precursors under conditions of photoinduced self-organization and microwave-induced self-organization (as well as to analyze the oscillatory impulse wave behavior of their self-organization products in ultrafine form as dispersed semiconductor devices). Approbation of this principle is carried out by means of projection onto the sphere of phase portraits of these types of vibrations, which is equivalent to the implementation of an operator that projects a 2D planar graph onto a 3D sphere.

Processing biological samples from simulated radiological terrorist events using Rapid DNA instruments

Two commercially available portable Rapid DNA instruments were evaluated for their ability to process 1 µL and 10 µL saliva samples deposited on metal and plastic surfaces and contaminated with surrogates of cesium (Cs)-137, strontium (Sr)-90 and cobalt (Co)-60; radioactive materials potentially released during a nuclear weapon accident or a radiological dispersal device detonation. A comparable success rate was noted for both Rapid DNA instruments when considering the number of complete and balanced DNA profiles, the number of profiles with a minimum of 10 autosomal STR loci (out of 23 [FlexPlex™ 27] or 21 [GlobalFiler™ Express]), and the possibility to search a national DNA database in Canada and the United States. Cobalt had an adverse impact on the quality of the megaplex short tandem repeat (STR) DNA profiles derived on each instrument for two of the three contamination levels tested in this study, i.e., 0.05 M and 0.1 M as reflected by a reduced number of detected alleles and decreased profile peak heights. Strontium exhibited some adverse effect on the Rapid DNA results when used at the highest contamination level (0.1 M) whereas cesium had none. No new artifacts were observed in the Rapid DNA profiles of samples spiked with the non-radiogenic surrogates. Importantly, in the context of a radiological/nuclear (RN) event, the ANDE™ 6C offers the possibility to dispose of all radioactive materials associated with contaminated samples quickly using a chip on which all steps of the Rapid DNA process are performed whereas the RapidHIT™ ID accumulates radioactive materials for many days before disposal. An individual handling 25 samples in a week (5 per day) on the RapidHIT™ ID at a 30.5 cm distance with a 5 min exposure to the radioactive source estimated at every run would exceed the 0.042 µSv/5 min limit with gamma dose rates for Cs at 0.13 mSv and for Co at 3.8 mSv. Beta dose rates calculated for the surrogate isotopes at the three concentrations tested were also above the recommended radiation exposure limit of 1 mSv/yr (0.042 µSv/5 min). Various potential mechanisms of action behind the interference noted for Sr and Co at high concentrations are presented. These elements may play a role in the steps prior to PCR (at the DNA molecule by binding to bases or to phosphate groups), during PCR (at the DNA polymerase as cofactors for catalytic sites), or even during amplified DNA fragment detection (as fluorescence quenchers).

Transient vacuolar changes of the crystalline lens in patients using a dispersive ophthalmic viscosurgical device.

To report the clinical prognosis and pathological findings of accidental lens vacuolar changes in eyes with intraoperative exposure to a dispersive ophthalmic viscosurgical device (OVD). Two patients who developed transient lens vacuolar changes during uneventful persistent pupillary membrane (PPM) removal surgery were presented and followed up. This event was speculated to be associated with an intraoperative dispersive OVD DisCoVisc (hyaluronic acid 1.6%-chondroitin sulfate 4.0%) exposure. Then, to provide the pathological basis for our speculation, another four cataract patients were randomly exposed to different OVDs, and their anterior lens capsules were investigated with transmission electron microscopy (TEM). After months, the subcapsular vacuoles in both PPM cases were gradually disappeared without visual deterioration. For the cataract patients, similar lens changes were observed intraoperatively in those exposed to a dispersive DisCoVisc but not a cohesive OVD IVIZ (sodium hyaluronate gel 1.0%). In addition, marked ultrastructural changes, including chromatin condensation, extensive cytoplasmic vacuoles, and obvious intercellular space between lens epithelial cells in the anterior lens capsules of all eyes exposed to DisCoVisc, were observed by TEM. The lens vacuolar changes may be associated with a dispersive OVD exposure. Therefore, it is not preferable to use dispersive OVDs in patients with transparent lenses or without the intention of lens extraction. In addition, close follow-ups instead of immediate lens extraction are recommended for the occurrence of similar lens lesions.

Consequence assessment of hypothetical urban radiological dispersal device incident in Korea

Radiological Dispersal Devices (RDDs) are designed to disperse radioactive material over a wide area, leading to significant consequences to the environment and public health. This paper discusses the radiological effects of a potential RDD detonation containing 137Cs and 241Am in the commercial area of Busan, South Korea. The assessment, conducted with HotSpot Health Physics and RESRAD-RDD codes, found that summer had the most significant impact, with a maximum total effective dose equivalent (TEDE) of 280 mSv at 100 m and this decreased to 1 mSv at 4.5 km from the detonation point within the time interval of 35 min.

Soil surface roughness impacts the risk arising from a hypothetical urban radiological dispersive device activation.

This study considers a deliberate hypothetical release of radioactive material over an inhabited urban zone. The event is initiated by the activation of a radiological dispersion device. The main threat is the deposition of radioactive material onto the soil's surface. The radiation represents the threat-defining risks, which depend on the main variables, i.e. soil surface roughness, sex, age of the exposed individuals and the moment of the release (day or nighttime). This study aims to evaluate the effect of soil surface roughness on the radiological risk. The simulation was performed by an analytical method using the HotSpot Health Physics code within the first 100h. The results found relevant elements that allow for differentiating consequences as a function of the time of release (whether daytime or nighttime), thus allowing decision-makers to be supported with a little more detail about the situation, although in a critical initial phase.

Management of Casualties from Radiation Events

Radiation events such as nuclear war, nuclear reactor incidents, and the deployment of a radioactive dispersal device (dirty bomb) are all significant threats in today’s world. Each of these events would bring significant challenges to clinicians caring for patients with burns and traumatic injuries who are also contaminated or irradiated. The result of a nuclear exchange in a densely populated area could result in thousands of patients presenting with trauma, burns, and combined injury (trauma and burn in an irradiated patient). In this review, we will discuss the three major types of ionizing radiation: alpha, beta, and gamma, and their respective health hazards and biological effects. Additionally, we will discuss the types of burn injuries in a nuclear disaster, caring for the contaminated patient, and managing the combined injury of burn trauma with acute radiation syndrome. The reader will also be left with an understanding of how to prioritize lifesaving interventions, estimate the absorbed dose of radiation, and predict the onset of acute radiation syndrome. While some animal models for morbidity and mortality exist, there is limited modern day human data for patients with combined injury and burns associated with a nuclear disaster due to the infrequent nature of these events. It is extremely important to continue multidisciplinary research on the prevention of, preparedness for, and the response to nuclear events. Furthermore, continued exploration of novel treatments for radiation induced burns and the management of combined injury is necessary.

Hybrid trust-based secure routing protocol for detection of routing attacks in environment monitoring over MANETs

Maintaining a healthy environment requires constant vigilance. Keeping constant tabs on environmental factors might be a useful tool in the fight against and recovery from environmental degradation. It is possible to send environmental data from strategically positioned sensors that monitor the surrounding circumstances. Environmentalists are the first to arrive at a disaster site, assess the situation, and take corrective measures. To get information from the sensors, they must coordinate with one another. Remote environmental sensing, the tracking from several physical systems, as well as risk assessment and management, have all seen significant improvements as a result of the use of these networks, which are comprised of many dispersed devices, each of which includes sensing, processing, and wireless technology capabilities. To facilitate communication between sensors and ecologists, the authors of this research suggest the usage of MANETs. To address these issues, a hybrid trust-based secure routing protocol is designed. Firstly, nodes are clustered using the Skill Optimization Technique. The Direct and Indirect (Hybrid) trust is computed using the Deep Q-Learning technique and then Routing is established using Diffusion Convolutional Neural Networks. With these methods, routing attacks such as Black Hole, Gray hole, and Wormhole attacks are identified and compared with the traditional security protocols using network simulation tools.

Attractiveness of Fissile Material in Nuclear Wastes from Different Fuel Cycles

Nuclear fuel cycle advancements will result in new types of fissile material, including nuclear wastes, that require security and safeguards. Nuclear wastes may be more vulnerable for diversion by non-state actors, and chemical processing to recover fissile material is not an insurmountable challenge. Previous work has applied a figure of merit (FOM) to assess material attractiveness and security risks. This analysis applies the material attractiveness FOM to wastes produced by fuel cycles from the Fuel Cycle Evaluation and Screening (FCES) study. Two aspects of security risk are studied: (1) the time before the fissile material in the waste becomes attractive and (2) the number of waste packages required to obtain a critical mass of fissile material. Two fuel cycles are presented to highlight detailed results: (1) once-through use of low-enriched U in light water reactors (LWRs) and (2) continuous recycle of Pu in sodium fast reactors (SFRs). Increasing LWR used nuclear fuel (UNF) package loading increases the time to attractiveness, but the larger packages contain enough Pu for multiple critical masses. The high-level waste (HLW) from processing the SFR fuels has similar FOM behavior but longer time to attractiveness due to the concentration of fission products. More HLW packages are required to obtain a critical mass; that number can be further increased by increasing the separation efficiency. Extended to all FCES fuel cycles, the minimum time before attractiveness is generally lower for UNF than for HLW because radioactivity is concentrated in HLW. For nearly all fuel cycles that produce UNF, only one package is required to recover enough fissile material for a critical mass. Notably, some advanced fuel cycles produce HLW, of which only two packages need to be recovered to obtain a critical mass, even when the target fissile material is recycled. Going forward, an assessment of the security risks posed by fissile material in nuclear wastes will need to quantify the challenge posed by separations. Ultimately, the assessment could inform security and response measures; whether any of the observations might affect these measures could be an area for future work. Finally, future analysis could study whether different fuel cycle wastes are more attractive for use in radiological dispersal devices or radiological exposure devices.

Intraocular Lens Unfurling Time Exponentially Decays with Increased Solution Temperature.

Intraocular lens (IOL) unfurling can be a rate-limiting step in cataract surgery, limiting operative efficiency. Furthermore, inefficient unfurling has important implications for clinical outcomes. We examine the effects of solution temperature on IOL unfurling time using three in vitro models of the ocular environment. IOLs were injected into a 6-well plate filled with balanced salt solution (BSS), dispersive ophthalmic viscoelastic device (OVD), or cohesive OVD. Experiments were also performed in a plastic eye filled with dispersive or cohesive OVD. IOL unfurling time was recorded against the temperature of the respective solution. IOL unfurling time decayed exponentially as solution temperature increased in all experiments, including the BSS-filled 6-well plate, the OVD-filled 6-well plate, and the OVD-filled plastic eye. IOLs failed to unfurl within 10 min at 10°C, below the glass transition temperature of the tested IOLs. Increasing solution temperature from 20°C to 30°C decreases IOL unfurling by greater than 2 min. Further heating to 40°C did not significantly decrease IOL unfurling time. Increased solution temperature rapidly decreases IOL unfurling time in vitro. IOLs do not unfurl within a clinically acceptable timeframe at or below their glass transition temperature. Increased BSS and/or OVD temperature may be a potential method to decrease IOL unfurling time in cataract surgery. However, future research is needed to elucidate potential consequences of warmed BSS and/or OVD on post-operative outcomes. This study demonstrates the potential for temperature regulation to decrease cataract surgery operative time and provides preliminary evidence to justify future clinical validation of this relationship.

Performance analysis of NOMA enabled multi-user co-operative IoT network with SWIPT protocol

This study investigates the performance of user equipments (UEs) and IoT devices in a multi-user (MU) multiple-input single-output (MISO) configuration based non-orthogonal multiple-access (NOMA) system. The proposed model includes a base station surrounded by many users and a number of dispersed IoT devices. In the considered MU IoT network scenario, power allocation coefficients are set to ensure that both the relaying UE and the targeted IoT device experience increased performance. To assist the intended IoT device with weak channel conditions, an optimal user selection method is developed that picks a UE with comparatively better reception, and thereby the selected UE acts as relay forward node utilizing the simultaneous wireless information and power transfer protocol. The characterization of a key performance metric, i.e., the outage probability is derived by adopting a two-step procedure. First, quadratic forms of signal to interference plus noise ratio (SINR) at the relaying UE and the signal-to-noise ratio (SNR) and SINR at the intended IoT device are constructed. Then, using the indefinite quadratic form approach, we arrive at closed-form expressions for the outage probability (OP) of intended IoT device under linearly dependent beamformers. To validate the analytical expressions provided in this study, simulations are performed. We demonstrate that by utilizing the proposed user selection technique in MU-MISO-NOMA system decreases the OP of the intended IoT device by 40% on average. Furthermore, utilizing multiple transmit antenna elements decreases the OP of the intended IoT device by approximately 10%.

Shaking Device for Homogeneous Dispersion of Magnetic Beads in Droplet Microfluidics

Magnetic beads (or particles) having a size between 1 and 5 µm are largely used in many biochemical assays devoted to both purification and quantification of cells, nucleic acids, or proteins. Unfortunately, the use of these beads within microfluidic devices suffers from natural precipitation because of their size and density. The strategies applied thus far to cells or polymeric particles cannot be extended to magnetic beads, mainly due to their magnetization and their higher densities. We report an effective shaking device capable of preventing the sedimentation of beads that are stored in a custom PCR tube. After the characterization of the operating principle, the device is validated for magnetic beads in droplets, leading to an equal distribution between the droplets, barely affecting their generation.

Security-Enhanced Electro-Optic Mutual Injection Secure Communication Scheme With Time-Delay Signature Suppressing

In this article, we propose and numerically demonstrate a novel dual-phase modulated time-delay signature (TDS) concealed communication system. The proposed system addresses the fatal disadvantage of conventional electro-optic chaotic systems in that TDS is vulnerable to detection. Combined with the dispersive devices ahead, which significantly expands the complexity of the signal, the scheme perturbs the transmitted data with the mutual injection of the feedforward and feedback branches in the phase, strengthening the nonlinear effect of the system considerably. In addition, the key space of the system against illegal users’ exhaustive attack within reasonable parameters reaches 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">19</sup> , which is 14 orders of magnitude larger than that of the classical electro-optic system. A confidential 32 G/s OOK signal was transmitted over 100 km and successfully recovered. Numerical results demonstrate that the chaotic system can tolerate minor parameter mismatches which are controllable in practice, proving that the system can be used for secure communication.

Inverse design of dispersion for photonic devices based on LSTM and gradient-free optimization algorithms hybridization

As an inherent property of optical devices, dispersion plays an important role in the areas of optical communication and nonlinear optics. Traditional dispersion optimization approaches are time-consuming and power-hungry. In this paper, to accelerate the design of dispersive optical devices, an indirect inverse design method based on the long short-term memory forward model combined with gradient-free optimization algorithms is proposed. In the case of photonic crystal fiber, the results show that the forward model can predict the group velocity dispersion (GVD) with an accuracy of up to 99.62%, and the calculation speed is more than one thousand times faster than the conventional numerical simulations. The prediction accuracy of the inverse model is higher than 93%, with a calculation time of less than 20 s. In the case of slot waveguide, the results show that the forward model can predict the GVD with a prediction accuracy of 96.99% and the inverse design accuracy goes to 99%. The proposed machine learning model offers an efficient tool for dispersion optimization in both fiber and waveguide platforms.

Contrastive Learning Over Random Fourier Features for IoT Network Intrusion Detection

IoT networks connect dispersed and heterogeneous devices with high economic impact, making them an important cybersecurity target. The changing nature of cybersecurity attacks requires intrusion detectors with the ability to detect new attacks. Our proposed model is a network intrusion detector created specifically for the needs of IoT networks with the aim of detecting previously unseen attacks. It is based on a shallow neural network architecture following a novel contrastive learning scheme. In this scheme, both the network features and the labels are projected into a common representation (embedding) space where a similarity score is defined. The labels act as a prototype for each type of traffic in embedding space, and classification is based on the proximity of samples to these class prototypes. The dimensionality and structure of the embedding space are critical. In this work, we explore the advantages of having an embedding space with expanded dimensionality using a kernel approximation technique (Random Fourier Features) that is integrated and learned within the neural network. To avoid overfitting, we investigate the importance of various regularization techniques (L2 and contractive). The resulting model is tested against three network intrusion detection datasets to assess its ability to detect known and unknown attacks (zero-shot learning). The experimental results show a higher ability of the proposed model to detect unknown attacks than similar models and alternative machine learning models, in the literature.

Mass Casualty Triage: What Works and Who Does it Best?

Introduction:There is a consensus that there lacks a standard for primary triage during mass casualty incidents. This is further compounded by a dearth of high quality research on the topic. Some studies suggest the superiority of SALT triage versus other triage systems, however, findings have not widely transitioned to clinical practice. We believe that despite specialized training including that in emergency medicine or emergency medical services (EMS), there will be significant variability amongst triage determination and use of triage methods. This study intends to analyze various provider skill levels and their accuracy of triage determination.Method:In a disaster exercise, a group of providers trained to use START triage were expected to triage, treat and determine transport order of the patients from a scenario of a simulated intentional radiological dispersal device (RDD) detonation with multiple casualties. Another group of providers trained to use SALT triage were expected to triage, treat, and determine transport order of patients from a scenario of a building collapse after a hurricane to assess SALT triage with the participating officers. Additional cohorts of EMS clinicians will be given the same case scenarios and asked to triage, treat when necessary, and determine transport order of the patients.Results:The initial data from the RDD exercise includes 102 patient case scenarios with 27 minimal (green), 40 delayed (yellow), and 35 immediate (red) patients. The providers involved in the exercise are trained at minimum to NREMT EMT level. Results showed an under-triage rate of 7.8%, an over-triage rate of 20.6% and overall accuracy of 71.6% when using START triage.Conclusion:The undertriage rate with START is 7.8% is higher than the generally acceptable rate of less than 5%. Our research is ongoing and we anticipate completion in 2023. We hope that our research provides future direction to improve triage in disaster scenarios.