Data Extraction on MTK-based Android Mobile Phone Forensics

In conducting criminal investigations it is quite common that forensic examiners need to recover evidentiary data from smartphones used by offenders. However, examiners encountered difficulties in acquiring complete memory dump from MTK Android phones, a popular brand of smartphones, due to a lack of technical knowledge on the phone architecture and that system manuals are not always available. This research will perform tests to capture data from MTK Android phone by applying selected forensic tools and compare their effectiveness by analyzing the extracted results. It is anticipated that a generic extraction tool, once identified, can be used on different brands of smartphones equipped with the same CPU chipset

Octogenarians with blunt splenic injury: not all geriatrics are the same.

Geriatric trauma patients (GTP) (age ≥ 65 years) with blunt splenic injury (BSI) have up to a 6% failure rate of non-operative management (NOM). GTPs failing NOM have a similar mortality rate compared to GTPs managed successfully with NOM. However, it is unclear if this remains true in octogenarians (aged 80-89 years). We hypothesized that the failure rate for NOM in octogenarians would be similar to their younger geriatric cohort, patients aged 65-79 years; however risk of mortality in octogenarians who fail NOM would be higher than that of octogenarians managed successfully with NOM. The Trauma Quality Improvement Program (2010-2016) was queried for patients with BSI. Those undergoing splenectomy within 6 h were excluded to select for patients undergoing NOM. Patients aged 65-79 years (young GTPs) were compared to octogenarians. A multivariable logistic regression model was used to determine the risk for failed NOM and mortality. From 43,041 BSI patients undergoing NOM, 3660 (8.5%) were aged 65-79 years and 1236 (2.9%) were octogenarians. Both groups had a similar median Injury Severity Score (ISS) (p = 0.10) and failure rate of NOM (6.6% young GTPs vs. 6.8% octogenarians p = 0.82). From those failing NOM, octogenarians had similar units of blood products transfused (p > 0.05) and a higher mortality rate (40.5% vs. 18.2%, p < 0.001), compared to young GTPs. Independent risk factors for failing NOM in octogenarians included ≥ 1 unit of packed red blood cells (PRBC) (p = 0.039) within 24 h of admission. Octogenarians who failed NOM had a higher mortality rate compared to octogenarians managed successfully with NOM (40.5% vs 23.6% p = 0.001), which persisted in a multivariable logistic regression analysis (OR 2.25, CI 1.37-3.70, p < 0.001). Late failure of NOM ≥ 24 h (vs. early failure) was not associated with increased risk of mortality (p = 0.88), but ≥ 1 unit of PRBC transfused had higher risk (OR 1.88, CI 1.20-2.95, p = 0.006). Compared to young GTPs with BSI, octogenarians have a similar rate of failed NOM. Octogenarians with BSI who fail NOM have over a twofold higher risk of mortality compared to those managed successfully with NOM. PRBC transfusion increases risk for mortality. Therefore, clinicians should consider failure of NOM earlier in the octogenarian population to mitigate the risk of increased mortality

The Uncertainty Aware Salted Kalman Filter: State Estimation for Hybrid Systems with Uncertain Guards

In this paper we present a method for updating robotic state belief through contact with uncertain surfaces and apply this update to a Kalman filter for more accurate state estimation. Examining how guard surface uncertainty affects the time spent in each mode, we derive a guard saltation matrix - which maps perturbations prior to hybrid events to perturbations after - accounting for additional variation in the resulting state. Additionally, we propose the use of parameterized reset functions - capturing how unknown parameters change how states are mapped from one mode to the next - the Jacobian of which accounts for the additional uncertainty in the resulting state. The accuracy of these mappings is shown by simulating sampled distributions through uncertain transition events and comparing the resulting covariances. Finally, we integrate these additional terms into the "uncertainty aware Salted Kalman Filter", uaSKF, and show a peak reduction in average estimation error by 24-60% on a variety of test conditions and systems.Comment: To appear in IROS 202

Effect of fatigue and hypohydration on gait characteristics during treadmill exercise in the heat while wearing firefighter thermal protective clothing.

This study compared the gait characteristics of individuals walking in heat while wearing firefighting equipment in fatigued and non-fatigued states. Nineteen subjects performed a 50-min treadmill protocol in a heated room while gait patterns were recorded using a digital video camcorder. Forty gait cycles were analyzed near the beginning (9 min) and at the end (39-49 min) of exercise. Spatio-temporal gait variables including step frequency, step length, swing time, stance time, cycle time and double-support time were determined. Gait variability was quantified by the standard deviation (SD) and coefficient of variation (CV) of each variable. Left-right symmetry was calculated using the symmetry index (SI) and symmetry angle (SA). Paired t-tests (alpha = 0.05) were performed to identify difference between the beginning and the end of the protocol for each measured variable. Spatio-temporal gait characteristics did not differ between the beginning and the end of exercise. Gait variability of the double-support time increased at the end as measured by both SD (P = 0.037) and CV (P = 0.030) but no change was observed for other variables. Left-right symmetry measured using either SI or SA did not differ between sessions. In summary, spatio-temporal gait characteristics and symmetry while wearing firefighting equipment are insensitive to physiological fatigue. Prolonged walking in heat while wearing firefighting equipment may increase gait variability and therefore the likelihood of a fall. Future studies are needed to confirm the potential relationship between fatigue and gait variability and to investigate the possible influence of individual variation

Dynamical modulation of solar flare electron acceleration due to plasmoid-shock interactions in the looptop region

A fast-mode shock can form in the front of reconnection outflows and has been suggested as a promising site for particle acceleration in solar flares. Recent development of magnetic reconnection has shown that numerous plasmoids can be produced in a large-scale current layer. Here we investigate the dynamical modulation of electron acceleration in the looptop region when plasmoids intermittently arrive at the shock by combining magnetohydrodynamics simulations with a particle kinetic model. As plasmoids interact with the shock, the looptop region exhibits various compressible structures that modulate the production of energetic electrons. The energetic electron population varies rapidly in both time and space. The number of 5$-$10 keV electrons correlates well with the area with compression, while that of $>$50 keV electrons shows good correlation with strong compression area but only moderate correlation with shock parameters. We further examine the impacts of the first plasmoid, which marks the transition from a quasi-steady shock front to a distorted and dynamical shock. The number of energetic electrons is reduced by $\sim 20\%$ at 15$-$25 keV and nearly 40\% for 25$-$50 keV, while the number of 5$-$10 keV electrons increases. In addition, the electron energy spectrum above 10 keV evolves softer with time. We also find double or even multiple distinct sources can develop in the looptop region when the plasmoids move across the shock. Our simulations have strong implications to the interpretation of nonthermal looptop sources, as well as the commonly observed fast temporal variations in flare emissions, including the quasi-periodic pulsations.Comment: accepted for publication in ApJ

Sensitivity improvement of an optical current sensor with enhanced Faraday rotation

A sensitivity improvement technique is proposed for a class of bulk-glass optical current sensors that employ a ferromagnetic field concentrator. The total effective optical path length is demonstrated theoretically to be an invariant regardless of the bulk glass thickness and consequently independent of the size of the concentrator gap opening. Thus, if the magnetic field is increased by reducing the gap size, the eventual Faraday rotation for a given electric current can be increased proportionally, leading to an improved device sensitivity. The dependence of the gap magnetic field on gap size is calculated with an equivalent circuit model, and this analytical treatment is compared with a dedicated finite element computer package. By taking account of various types of optical power losses present in the bulk glass, the above formulated gap dependence of magnetic field is used to aid a realistic assessment of device sensitivity and this serves as a tool to design and analyze practical bulk-glass optical current sensors. A detailed experimental study to confirm the proposed sensitivity improvement technique is also reported

The Acceleration and Confinement of Energetic Electrons by a Termination Shock in a Magnetic Trap: An Explanation for Nonthermal Loop-top Sources during Solar Flares

Nonthermal loop-top sources in solar flares are the most prominent observational signature that suggests energy release and particle acceleration in the solar corona. Although several scenarios for particle acceleration have been proposed, the origin of the loop-top sources remains unclear. Here we present a model that combines a large-scale magnetohydrodynamic simulation of a two-ribbon flare with a particle acceleration and transport model for investigating electron acceleration by a fast-mode termination shock at the looptop. Our model provides spatially resolved electron distribution that evolves in response to the dynamic flare geometry. We find a concave-downward magnetic structure located below the flare termination shock, induced by the fast reconnection downflows. It acts as a magnetic trap to confine the electrons at the looptop for an extended period of time. The electrons are energized significantly as they cross the shock front, and eventually build up a power-law energy spectrum extending to hundreds of keV. We suggest that this particle acceleration and transport scenario driven by a flare termination shock is a viable interpretation for the observed nonthermal loop-top sources.Comment: submitted to ApJ

Effects of Coronal Magnetic Field Configuration on Particle Acceleration and Release during the Ground Level Enhancement Events in Solar Cycle 24

Ground level enhancements (GLEs) are extreme solar energetic particle (SEP) events that are of particular importance in space weather. In solar cycle 24, two GLEs were recorded on 2012 May 17 (GLE 71) and 2017 September 10 (GLE 72), respectively, by a range of advanced modern instruments. Here we conduct a comparative analysis of the two events by focusing on the effects of large-scale magnetic field configuration near active regions on particle acceleration and release. Although the active regions both located near the western limb, temporal variations of SEP intensities and energy spectra measured in-situ display different behaviors at early stages. By combining a potential field model, we find the CME in GLE 71 originated below the streamer belt, while in GLE 72 near the edge of the streamer belt. We reconstruct the CME shock fronts with an ellipsoid model based on nearly simultaneous coronagraph images from multi-viewpoints, and further derive the 3D shock geometry at the GLE onset. The highest-energy particles are primarily accelerated in the shock-streamer interaction regions, i.e., likely at the nose of the shock in GLE 71 and the eastern flank in GLE 72, due to quasi-perpendicular shock geometry and confinement of closed fields. Subsequently, they are released to the field lines connecting to near-Earth spacecraft when the shocks move through the streamer cusp region. This suggests that magnetic structures in the corona, especially shock-streamer interactions, may have played an important role in the acceleration and release of the highest-energy particles in the two events.Comment: Accepted for publication in Ap

Carbon Monoxide Protects against Hepatic Ischemia/Reperfusion Injury via ROS-Dependent Akt Signaling and Inhibition of Glycogen Synthase Kinase 3β

Carbon monoxide (CO) may exert important roles in physiological and pathophysiological states through the regulation of cellular signaling pathways. CO can protect organ tissues from ischemia/reperfusion (I/R) injury by modulating intracellular redox status and by inhibiting inflammatory, apoptotic, and proliferative responses. However, the cellular mechanisms underlying the protective effects of CO in organ I/R injury remain incompletely understood. In this study, a murine model of hepatic warm I/R injury was employed to assess the role of glycogen synthase kinase-3 (GSK3) and phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways in the protective effects of CO against inflammation and injury. Inhibition of GSK3 through the PI3K/Akt pathway played a crucial role in CO-mediated protection. CO treatment increased the phosphorylation of Akt and GSK3-beta (GSK3β) in the liver after I/R injury. Furthermore, administration of LY294002, an inhibitor of PI3K, compromised the protective effect of CO and decreased the level of phospho-GSK3β after I/R injury. These results suggest that CO protects against liver damage by maintaining GSK3β phosphorylation, which may be mediated by the PI3K/Akt signaling pathway. Our study provides additional support for the therapeutic potential of CO in organ injury and identifies GSK3β as a therapeutic target for CO in the amelioration of hepatic injury