We present strategies for decision making under uncertainty and adversary action modeling for small UAV operations. Uncertainty comes from the stochastic nature of the environment and from incomplete ...knowledge of adversary actions/behaviors. A stochastic dynamic programming approach is used to optimize (continuous) resource allocation (fuel reserves) in the face of uncertainty. Different scenarios for adversary responses are considered and analyzed in simulation.
Optimal Sequential Inspection Pachter, M.; Chandler, P.R.; Darbha, S.
Proceedings of the 45th IEEE Conference on Decision and Control,
2006-Dec.
Conference Proceeding
In this paper, we consider a problem of sequential resource allocation. Such a problem arises in a simplified intelligence, surveillance and reconnaissance (ISR) scenario where a micro air vehicle ...(MAV) is tasked with search and classification in an environment with false targets. The MAV visits the objects of interest in a specified sequence for classification. A human operator aids classification of objects based on the images sent to him from the MAV and the operator may request that the object be revisited if he requires further information. Such a request is made at most once by the operator for each object. The information gained by the operator when any object is revisited is the same. There is a random delay in communicating his findings to the MAV and the probability density function of the delay is assumed known. The MAV has a finite fuel reserve and upon receiving the feedback from the operator, it must decide whether to revisit the object or whether to continue to the next object in the sequence. In every revisit, fuel is expended from the reserve and equals twice the delay plus a fixed fuel cost. The objective is to maximize the number of revisits so as to maximize the information gained about the objects, which enables them to be classified as targets or false targets. Using stochastic dynamic programming, we show that there is a threshold delay for each object and it is optimal to revisit the object if the operator delay is smaller than the threshold and not to revisit otherwise
Therapeutic delivery of human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMs) represents a novel clinical approach to regenerate the injured myocardium. However, methods for robust ...and accurate in vivo monitoring of the iCMs are still lacking. Although superparamagnetic iron oxide nanoparticles (SPIOs) are recognized as a promising tool for in vivo tracking of stem cells using magnetic resonance imaging (MRI), their signal persists in the heart even weeks after the disappearance of the injected cells. This limitation highlights the inability of SPIOs to distinguish stem cell viability. In order to overcome this shortcoming, we demonstrate the use of a living contrast agent, magneto-endosymbionts (MEs) derived from magnetotactic bacteria for the labeling of iCMs. The ME-labeled iCMs were injected into the infarcted area of murine heart and probed by MRI and bioluminescence imaging (BLI). Our findings demonstrate that the MEs are robust and effective biological contrast agents to track iCMs in an in vivo murine model. We show that the MEs clear within one week of cell death whereas the SPIOs remain over 2 weeks after cell death. These findings will accelerate the clinical translation of in vivo MRI monitoring of transplanted stem cell at high spatial resolution and sensitivity.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The cooperative control of multiple unmanned air vehicles (UAVs) poses significant theoretical and technical challenges. This research addresses the specific problem of the coordination of rendezvous ...of multiple UAVs at a predetermined target location. The rendezvous problem is posed as an optimization problem where the objective is to maximize the survivability of the UAV team, while constraining the UAVs to arrive at the target simultaneously. A decomposition strategy is proposed that allows optimization and guidance computations to be decentralized among the UAVs. The approach takes into account the threat and fuel situation of each UAV, while requiring only modest communication among the UAVs. Simulation results demonstrating the feasibility of the approach are presented.
IMPORTANCE: Controlling myopia progression is of interest worldwide. Low-dose atropine eye drops have slowed progression in children in East Asia. OBJECTIVE: To compare atropine, 0.01%, eye drops ...with placebo for slowing myopia progression in US children. DESIGN, SETTING, AND PARTICIPANTS: This was a randomized placebo-controlled, double-masked, clinical trial conducted from June 2018 to September 2022. Children aged 5 to 12 years were recruited from 12 community- and institution-based practices in the US. Participating children had low to moderate bilateral myopia (−1.00 diopters D to −6.00 D spherical equivalent refractive error SER). INTERVENTION: Eligible children were randomly assigned 2:1 to 1 eye drop of atropine, 0.01%, nightly or 1 drop of placebo. Treatment was for 24 months followed by 6 months of observation. MAIN OUTCOME AND MEASURES: Automated cycloplegic refraction was performed by masked examiners. The primary outcome was change in SER (mean of both eyes) from baseline to 24 months (receiving treatment); other outcomes included change in SER from baseline to 30 months (not receiving treatment) and change in axial length at both time points. Differences were calculated as atropine minus placebo. RESULTS: A total of 187 children (mean SD age, 10.1 1.8 years; age range, 5.1-12.9 years; 101 female 54%; 34 Black 18%, 20 East Asian 11%, 30 Hispanic or Latino 16%, 11 multiracial 6%, 6 West/South Asian 3%, 86 White 46%) were included in the study. A total of 125 children (67%) received atropine, 0.01%, and 62 children (33%) received placebo. Follow-up was completed at 24 months by 119 of 125 children (95%) in the atropine group and 58 of 62 children (94%) in the placebo group. At 30 months, follow-up was completed by 118 of 125 children (94%) in the atropine group and 57 of 62 children (92%) in the placebo group. At the 24-month primary outcome visit, the adjusted mean (95% CI) change in SER from baseline was −0.82 (−0.96 to −0.68) D and −0.80 (−0.98 to −0.62) D in the atropine and placebo groups, respectively (adjusted difference = −0.02 D; 95% CI, −0.19 to +0.15 D; P = .83). At 30 months (6 months not receiving treatment), the adjusted difference in mean SER change from baseline was −0.04 D (95% CI, −0.25 to +0.17 D). Adjusted mean (95% CI) changes in axial length from baseline to 24 months were 0.44 (0.39-0.50) mm and 0.45 (0.37-0.52) mm in the atropine and placebo groups, respectively (adjusted difference = −0.002 mm; 95% CI, −0.106 to 0.102 mm). Adjusted difference in mean axial elongation from baseline to 30 months was +0.009 mm (95% CI, −0.115 to 0.134 mm). CONCLUSIONS AND RELEVANCE: In this randomized clinical trial of school-aged children in the US with low to moderate myopia, atropine, 0.01%, eye drops administered nightly when compared with placebo did not slow myopia progression or axial elongation. These results do not support use of atropine, 0.01%, eye drops to slow myopia progression or axial elongation in US children. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03334253
Antigen-presenting cells (APCs) can induce tolerance or immunity. We describe a subset of human APCs that express indoleamine 2,3-dioxygenase (IDO) and inhibit T cell proliferation in vitro. ...IDO-positive APCs constituted a discrete subset identified by coexpression of the cell-surface markers CD123 and CCR6. In the dendritic cell (DC) lineage, IDO-mediated suppressor activity was present in fully mature as well as immature $CD123^+ DCs$. $IDO^+ DCs$ could also be readily detected in vivo, which suggests that these cells may represent a regulatory subset of APCs in humans.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, ...biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al., 2003; Williams et al., 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al., 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggested the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer sediments desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ∼3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction in the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in aquifers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper, we have considered the problem of velocity and range estimation for an UAV using a camera and the knowledge of linear speed through a GPS device. In our earlier work (2006), a method ...for decomposition of a scene into structure blocks, and finding correspondences between such blocks in successive frames was developed. The result of this low-level image processing is (a) a set of structure blocks; (b) the motion of each structure block; and (c) a reliability index between zero and one denoting the confidence of the solution in (b). Here, we show that by solving a constrained optimization problem set up using the results of the image processing, one can obtain the linear and angular velocity of the camera motion, provided the speed of the linear motion is known. Once the velocity parameters is computed, we show how the range to objects in the field of view can be computed
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