① Ben Afman Case Study

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Ben Afman Case Study



Victor Ben Afman Case Study Alfen - This Ben Afman Case Study discusses the Ben Afman Case Study paradigm differences separating commercial UAVs and General Effects Of Technology In The Pedestrian, placing strict emphasis in the fact that a UAV should be crash-safe by design. In: Business and Management. In healthy Ben Afman Case Study, of the parameters showed a time course response. Because Ben Afman Case Study the deployment speed of such systems, Ben Afman Case Study minimum altitude Ben Afman Case Study is not as constrained as with the parachute. Additional file 2: Figure S1 A—F. Occurrence of any infection during Ben Afman Case Study was abstracted from medical records.

WHO IMCI training video - Case study 1

In particular, algorithms that are adaptive, reconfigurable or non-deterministic in nature present the greatest challenge to design-time verification approaches. A schematic of the run-time assurance methodology is illustrated through Figure 4. In a run-time assurance framework, the primary advanced algorithm is responsible for achieving all performance objectives. These algorithms can be non-deterministic, adaptive, and enabled at all times under nominal conditions even though it is difficult to fully certify at design time. However, the backup system Fail-Safe hides in the background and is composed of a simplified control system with emphasis on safety rather than performance.

It does not posses advanced features that are difficult and expensive to certify. Hence, this control law is certified at design time using state of the art traditional methods. The RTA monitor and transition control continually monitors the overall state of the system, including critical parameters such as safety and operational limits, as it compares against validated representation of safe operating envelope. If a violation occurs, the transition controller disables the advance system and transfers control back to the backup system. It should be noted that these are also counter-measures that are being explored by the different security authorities around the globe as a way to control the threat that UAVs can represent.

Since they work on unlicensed bands and standard technologies it is quite easy to physically disrupt the communication channels used for controlling the drone or for its telemetry. Now someone can purposely cut the communications of a UAV. Depending on its fail-safe program, he could therefore be taking down the system, which would hover and eventually land, to grab its payload, or simply steal the expensive UAV. The notion of coexistence as it was studied between WiFi and Bluetooth is a challenge if you extend the number of competing and incompatible technologies and users.

With the advances in cheap electronic COTS , GPS scrambler units even though they are illegal in some countries, we are not here considering people that abide the law or Software Defined Radio, it is feasible to make the RTH difficult or impossible: the issue is eventually a crash or un-managed landing. But with the use of general RC communication technologies or more domestic wireless ones such as Bluetooth or WiFi, or analog video, one could conduct more advances cyber attacks such as trying to gain access to the telemetry or the video feeds, getting data and even taking the control of part of the remote systems. Examples of hijacking drones have been studied and published [ 21 ].

Even without having access to the embedded software, remote activation and destabilization could be the result of well thought fuzzing for example. The implementations of all the protocols used in these systems should be tested against such attacks. Since most of the Ground Stations are installed on more general systems PCs, SmartPhones , they could be used as Trojans and leave backdoor to access the data and controls of the drone. When updating the firmware by downloading new ones from the internet, the same type of attacks could be performed. In the same principle as the one used to ensure that the controller of the UAV behave correctly, supervision could be used to monitor the software behavior of the controller, i.

Recently, proof of concepts of very advanced attacks such as GPS spoofing have made the headlines [ 28 , 29 ]. Using this, a UAV path could be diverted to any other location the attacker would want to. Regarding security and safety in general, the last important point is to develop forensic for the recovered drones and ground stations so that information such as proofs of wrongdoing and identification of the wrongdoers can be collected. Up to this point, with the exception of redundant control boards, software-based approaches for making UAVs safer has been the focus of this article.

As the avionics become increasingly involved, the cost of developing and maintaining overly complex software may reach its limit and become prohibitive. Hence, in some cases it may be more efficient to have simpler software combined with efficient safety features that are implemented at the hardware level. This approach is coherent with the current regulation mindset that tolerates crashes as long as they are safe for people on the ground. In what follows, several hardware solutions will be discussed that could be used for civilian UAVs, with special emphasis on the growing multi-rotors scene as they seem to be the most popular platform employed for commercial applications. As discussed earlier, the main safety requirement is about humans.

Therefore, most safety specifications are based on potential injuries to the human body. As the head is naturally exposed to vehicles falling from the sky, blunt head trauma is one of the most likely injury that can have devastating short and long term effects [ 14 ]. Therefore, reducing the projectile impact energy, in this case the falling UAV, is the aim of this topic. The French regulatory agency, for example, limits the allowable impact energy to 69 Joules [ 12 ].

The most common device actually used for UAVs is the parachute. Since its popularization during WWI, this technology has matured and is now a relatively reliable solution for slowing down objects. However, in order for a parachute to have time and open, a minimum flight altitude is required. If maximum altitudes are explicitly defined by most regulations, it is down to the operator to fly its UAV in order to assure the proper functioning of the device in order to limit impact energy.

This is because most regulations prevent UAVs flights over populated area, but as we move forward, rules similar to general aviation will have to be put in place regarding flying over populated areas. These rules should integrate the recovery systems capabilities of current UAVs and maybe impose what type of technology to use. Predefined take-off and landing site may also be part of the solution to safely get to the minimum altitude. Another critical component to parachute operation is its passive nature when it comes to wind. The highest it is deployed, the more uncertain the landing spot becomes [ 19 ]. This is true in the event of an engine jam at full throttle on a run-away UAV. Therefore, deploying the parachute as soon as possible may not be the best strategy.

Note that parachutes need to be inspected and re-folded regularly generating room for error, especially if this task is not performed by a professional. In the end, parachutes, if use correctly, can be efficient devices. However, due to the low tolerance for failure, imposing regulations on the technology itself seems necessary, as is the usage of complementary technologies to reduce the impact trauma on the surrounding civilians. As we discussed previously, a major drawbacks for parachutes is the passive, often uncontrolled, nature of the fall. Controllable para-foils or ram-air can be used in exchange, but with the same other drawback of a parachutes.

Therefore, the use of failure-dedicated control surfaces as an integrated part of the system becomes worthy of discussion. Such a device could allow a failed system to navigate away from a crowd and is likely to reduce the impact energy. A thorough investigation revealed that similar concepts have been developed in recent years [ 20 ]. Furthermore, it was noted that the real-state impact and weight associated could be kept at minimum on a classical multi-rotor. In complement to control surfaces, a lifting component could be added to better slow down the fall.

To conclude, the need for hybrid vehicles that combine wings and stationary flight capabilities is already present, and it is simply a matter of time before purely vertical flight UAVs such as the classical multi-rotors become a thing of the past. Parachutes and lifting surfaces mainly aim at lowering impact velocity, but it has been discussed that another way to minimize impact energy would be to reduce the UAVs mass through a controlled disintegration. Strategically destroying the vehicle is definitely not appropriate for general aviation where the safety of the people on board is the priority, but with UAVs it becomes a interesting and viable option. This option has been discussed in the distant but not antithetical context of asteroid deflection [ 5 ] where transforming a big mass into a cloud of smaller debris allows for a better dissipation of energy into the atmosphere.

If the explosion is quite dramatic for asteroid deflection nuclear explosion! Polymer-bonded explosives PBX for example, exhibit good strength and machining capabilities [ 7 , 6 ]. This material could therefore be used for making specific parts of the vehicle to provide controlled destruction capabilities of the UAV. Sequential destruction strategies could then be though of to intelligently reduce the vehicle into smaller pieces, possibly through a chain reaction as is done in building demolition [ 8 ] or rocket stage separation [ 9 ]. Despite they intimidating nature, pyrotechnics are now a well mastered technology that the general public is subjected to on a daily basis [ 11 ] and could very well play a major role in the UAVs of tomorrow.

Restricted kinematic energy at impact is necessary to minimize the risk of blunt trauma, but one must realize that it is definitely not enough to ensure the physical integrity of people on the ground. The overall geometry of the vehicle is therefore fundamental in preventing fractures and penetrating trauma. Ducted fans and smooth structures i. Note that a real full scale UAV collision with a human dummy will be performed at Georgia Tech this summer to study the technical and legal repercussions of such an incident. Following this idea, we will discuss 3 solutions to reduce impact stress of crashing UAVs.

The automotive industry introduced airbags in the mids which has had a very positive impact on the reduction of accident casualties [ 15 ]. It is very efficient to absorb energy during a shock and reduce the impact force. Research has been done for this specific use of airbags [ 3 ] and companies are even developing dedicated products for UAV applications [ 2 ]. It is interesting to note that at the moment, airbags are only used to prevent damage to the vehicle, but could be a key player in protecting civilians as well.

If asking everybody to wear a personal airbag seems a bit out of proportion, even though it is not completely unimaginable [ 10 ] , requiring that all UAVs carry an airbag system activated in case of emergency would make sense. Used in conjunction with energy reducing features, airbags may prove very efficient at minimizing human injuries, especially because of their very fast speed of deployment [ 16 ]. Note that the deployment trigger can obviously not be the impact itself like in cars, and that a preventive strategy is needed. Because of the deployment speed of such systems, the minimum altitude requirement is not as constrained as with the parachute. As seen earlier in [ 4 ] , propellers present with their sharp profile and fast rotating speed are an important danger for humans, even when the vehicle is not moving.

To address this specific threat, several passive solutions can be implemented like ducted fans or protection shells [ 17 ]. Furthermore, active solution can also implemented in the same vain as controlled disintegration, were propellers could be jettisoned in case of emergency. This is particularly relevant in case of motor controller lockup. Through proper design, the jettisoned propellers could use their own shape to slow down their descent like maple keys falling from the trees.

This way, the rotational energy of the propellers is reduced because not attached to the rotor anymore and they become much less harmful to people on the ground. One obvious problem with this approach is the fact that now you have a UAV free falling out of control. Also, motor brakes could be implemented on the same model as for [ 18 ] but specifically designed for electric motors. The various plasma free fatty acids either showed the same time cluster 1 response as NEFA or decreased plasma concentrations with subsequent recovery cluster 3 response.

Subsequently, also the plasma monoglycerides and diglycerides showed increased concentrations after a lag time cluster 1. Leptin, the hormone that regulates the amount of fat storage, is secreted when the amount of fat storage has reached a certain threshold. This adipokine showed increased concentrations in the late time frame of PFT response cluster 1. Measuring serum creatinine is the most commonly used indicator of renal function. Creatinine showed decreased concentrations in response to PFT cluster 2. Urea, which is formed in the urea cycle by deamination of amino acids in the liver, is a waste product excreted by the kidney in the urine.

Also, urea showed decreased concentrations in response to PFT cluster 2. Together, these observations suggest that glomerular filtration rate of kidneys increased in response to PFT. Together, this suggests that there was a temporarily reduced vascular response after PFT. Most plasma amino acids showed a classic absorption profile in response to PFT cluster 5. This is a rapid increase which returns to baseline within 4—5 h and with concentrations below fasting concentration at the final time point 8 h. Some of the amino acids, however, showed decreased concentrations in response to PFT glycine and tryptophan, cluster 2. The amino acid derivatives 3-methylhistidine and 1-methylhistidine together with creatinine that originate from muscle showed linear decreasing concentrations in response to PFT cluster 2.

Together, this suggests that muscle turns into an anabolic state after consumption of PFT. The glycolysis intermediate pyruvate showed a classic absorption profile cluster 5 , similar to glucose and most amino acids. Glycerolphosphate, an intermediate metabolite derived from glycolysis, accumulated in plasma cluster 1 profile. Plasma lactate showed linear decreased concentrations cluster 2. This suggests that ATP was mainly aerobically produced and that the process of oxidative phosphorylation may have reached its maximum capacity. The TCA cycle intermediates succinate, malate, and citrate showed temporarily decreased plasma concentrations in response to PFT cluster 3 , whereas alpha-ketoglutarate showed increased concentrations after a lag phase cluster 1 in response to PFT.

Hepatic very low-density lipoprotein VLDL production represented by free cholesterol and sphingomyelins showed continuously increasing concentrations in response to PFT after a lag phase of about 2 h cluster 1. Highest levels were reached at the final time point 8 h. After about 4 h maximum TG, plasma concentrations were reached cluster 4 , which were normalized at the final time point 8 h. PFT caused a temporary release of both C-peptide and insulin from the pancreatic beta cells into the circulation with maximum concentrations around 1 h cluster 5. Glucagon also showed a temporary release during PFT but at a later stage with maximum concentrations around 4 h cluster 4.

Several markers related to oxidative stress responded to PFT. The antioxidant uric acid showed temporarily increased concentrations cluster 5 , whereas the antioxidant vitamin E and mannose ER stress showed temporary reduced concentrations cluster 3 response. Finally, erythronic acid, a molecule formed when N -acetyl- d -glucosamine is oxidized, showed temporarily increased concentrations in the late phase of the time course cluster 4 response. RQ returned to fasting values at min. Levels of several biomarkers were significantly different in T2D as compared to healthy subjects at fasting Table 2. A total of 18 out of parameters were statistically different in T2D as compared to healthy subjects.

Markers related to insulin and glucose metabolism were significantly different between the T2D and healthy subjects at fasting such as increased glucose, insulin, and HbA1C. Other plasma metabolites related to glucose metabolism showed lower 1,5-anhydroglucitol, glycine or higher mannose, fructose, valine, leucine, 2-hydroxybutanoic acid plasma concentrations in T2D. Leptin concentrations were significantly higher in the T2D patients, suggesting higher adiposity, which was confirmed by a higher BMI in T2D. Plasma concentrations of ALAT and GGT were found to be significantly elevated as compared to the healthy volunteers at fasting, suggesting reduced liver integrity in T2D. A total of 58 out of parameters showed a statistically different challenge effect in T2D as compared to healthy subjects Fig.

The responses of the phenotypic processes that were differentially modulated by PFT in T2D as compared to healthy controls are described in more detail below. Overview of markers that have a different PhenFlex test response between 20 healthy male and 20 male type 2 diabetic patients. A delayed insulin response was found with maximum concentrations at the 2-h time point in T2D, as compared to the 1-h time point in healthy subjects. For C-peptide, maximum concentrations were reached at the 4-h time point in T2D, as compared to the 2-h time point in healthy subjects. The gut hormone GLP-1, closely connected to glucose metabolism, showed higher maximum concentrations as well as a faster return to homeostatic levels in T2D as compared to healthy subjects.

The response to PFT revealed a diminished lipolysis rate and leptin response in T2D as compared to healthy subjects. No difference in response was observed for the essential FFA between T2D and healthy male volunteers. A distinctly different response to PFT between T2D and healthy subjects was observed for most proteinogenic amino acids. This suggests a different protein metabolism between the two groups. Fourteen out of 19 proteinogenic amino acids showed a differential PFT response. Similar differences in PFT response profiles were observed for serine, lysine, threonine, glutamate, and tyrosine. Finally, alanine, asparagine, glutamine, cysteine, and phenylalanine also showed a differential PFT response in T2D as compared to healthy that differed from the above described amino acids.

Three metabolites that are intermediates of energy metabolism responded differently to PFT between T2D and healthy subjects. These were alpha-ketoglutarate, succinate, and pyruvate. Together, PFT response profiles from these metabolites suggest that T2D have a diminished carbohydrate metabolism shown by higher amplitudes for glycolysis and TCA cycle as compared to healthy subjects. The ketone bodies 3-hydroxybutanoic acid and acetoacetate both involved in ketogenesis showed a reduced response in T2D as compared to healthy subjects. The minimum concentrations were reached at a later time point 4 vs. Together these data further confirmed a reduced hepatic tissue injury control in T2D. Finally, in response to PFT, several markers related to oxidative stress showed a differential response in T2D as compared to healthy subjects.

Glutathione ratio and levels of ribose were significantly lower in T2D as compared to healthy subjects. The response of erythronic acid was found to be strikingly different between the two groups. Similar glucose and insulin patterns were observed between the two subjects groups Fig. Although the direction of change was the same for all indexes after OGTT and PFT, the absolute values for the indexes were different after the two challenges, especially for DI 6.

Furthermore, it was observed that healthy subjects had a remarkable higher standard deviation for the different indexes as compared to T2D. PhenFlex test in 20 diabetic type 2 male patients and 20 healthy male volunteers. The goal of this clinical study was to characterize PFT by assessing the healthy adaptive capacity of relevant metabolic processes as determined from the literature review [ 3 ]. In other words, this study examined to what extent a series of biomarkers, representing the selected health related processes, are responsive to the PhenFlex challenge in our healthy volunteers.

Processes represented in Fig. These findings, including a lack of response of CRP, are in accordance with what is described in the literature [ 3 ]. Also, most markers related to oxidative stress represented by uric acid, vitamin E, ribose, erythronic acid, and mannose showed a significant time response as well as metabolic flexibility RQ. These processes are known to be augmented by a mixed meal challenge as compared to single macronutrient challenges such as OGTT and oral lipid tolerance test OLTT [ 3 , 8 ].

Therefore, we conclude that PFT modulated phenotypic flexibility as expected in healthy individuals. Five distinct response type profiles were identified Fig. However, some differences can be observed between the biomarker responses in the two studies. For example, cluster 5 is a collection of markers such as glucose, insulin and most amino acids that are being represented into two distinct clusters in the Pellis study [ 7 ] that differ in the time that minimum values are being reached 4 and 6 h after postprandial challenge.

The studies differ in the composition of the challenge tests and study set-up 4 h of fasting after a standardized breakfast vs. This shows that it is important that a standardized nutritional challenge protocol is being developed in order to compare results between studies and for the interpretation of the challenge test response profiles. The secondary objective was to investigate whether PFT and defined new biomarkers are useful to demonstrate reduced phenotypic flexibility in metabolically impaired subjects, in this case, T2D, as compared to healthy subjects.

The phenotypic flexibility markers showed a more sensitive response than the fasting markers Fig. Based on challenging conditions, our results evidently confirmed that T2D is a systems disease with an impaired adaptive response of pancreas, liver, muscle, adipose, gut, systemic stress, vasculature and kidney Fig. This is in agreement with the acknowledgement of eight organs that are important players in the hyperglycemic phenotype of T2D [ 29 ]. With the exception of brain insulin resistance, all other seven players that have an important role in this hyperglycemic phenotype were identified by looking at the phenotypic flexibility response.

Furthermore, many of the metabolites that were found to be significantly different between T2D and healthy that were observed in our study are quite well known from metabolic profiling studies in diabetes [ 31 ]. Amino acids, in particular, the branched-chain amino acids and glycine, carbohydrates including 1,5-anhydroglucitol and ketone bodies including alpha-hydroxybutyrate all have been identified as predictive biomarkers for T2D [ 31 ]. So far, the effect of aging on phenotypic flexibility has not been studied, so it has to be speculated to what degree this influenced our results. Probably aging deteriorates most health-related processes to a certain extent.

Still, our study provides an accurate picture of metabolic dysregulation in diabetes pathology as we know it from literature, indicating the power and sensitivity of the phenotypic flexibility approach. PFT was compared to OGTT, and although the amplitude and peak of both glucose as well as insulin was reduced in PFT, different insulin sensitivity indexes disclosed similar statistical differences. Based on these results we conclude that PFT can be used to study differences in glucose and insulin metabolism. The reduced glucose and insulin amplitude and delayed peak in response to PFT may be the result of delayed gastric emptying.

Furthermore, healthy subjects had a remarkable higher heterogeneity for the different insulin sensitivity indexes both based on OGTT as well as on PhenFlex challenge. This was also checked for the other parameters quantified in this study, but not such differences were being observed for other markers between the two groups. When obvious differences in standard deviation were present, it was either in the healthy group of volunteers as well as in T2D. The current results may suggest that OGTT is more sensitive in the identification of insulin-related effects. The added value of PFT is that it augments processes of endothelial integrity, hepatic tissue injury, oxidative stress as well as metabolic flexibility which are important processes in the determination of metabolic health.

Taken together, PFT thus provides more accurate information on a broad spectrum of phenotypic flexibility processes. We, therefore, propose PFT as a standardized mixed meal tolerance test in metabolic and nutritional studies. The results suggest that PFT is applicable for examining health effects of a broad range of diets and dietary-ingredients and provides valuable additional information as compared to the oral glucose tolerance test. Nancy Ann Alford - Mary C. Alger - Charles Elmer Allego - Adele "dell" Reed Allen - Alphonzo Allen - Anna C.

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