Modeling time-varying uncertain situations using Dynamic Influence Nets

AbstractThis paper enhances the Timed Influence Nets (TIN) based formalism to model uncertainty in dynamic situations. The enhancements enable a system modeler to specify persistence and time-varying influences in a dynamic situation that the existing TIN fails to capture. The new class of models is named Dynamic Influence Nets (DIN). Both TIN and DIN provide an alternative easy-to-read and compact representation to several time-based probabilistic reasoning paradigms including Dynamic Bayesian Networks. The Influence Net (IN) based approach has its origin in the Discrete Event Systems modeling. The time delays on arcs and nodes represent the communication and processing delays, respectively, while the changes in the probability of an event at different time instants capture the uncertainty associated with the occurrence of the event over a period of time

Incorporating Heterogeneity in Command Center Interactions

One of the many complexities of multinational coalition operations stems from differences in culture, military procedures, and command and control processes between the cooperating command centers. These differences can influence the interactions between decision makers of different command centers and can affect the outcome of the coalition operation. A coalition model, composed of individual models of the five-stage interacting decision maker model, was used in a virtual experiment. The subjective parameters included in the decision maker model can be any attribute that characterizes the heterogeneity of the decision makers. In this case, the parameters of power distance and uncertainty avoidance were used, two of Hofstede\u27s (1991) cultural dimensions. The accuracy and timeliness of the coalition\u27s response was used to evaluate its performance as a function of heterogeneity. Including the presence of heterogeneity in the coalition model, through the use of subjective parameters, is the first step in formalizing the process for developing adaptive coalition architectures

A Model to Evaluate the Effect of Organizational Adaptation

When an organization’s output declines due to either internal changes or changes in its external environment, it needs to adapt. In order to evaluate the effectiveness of different adaptation strategies on organizational per- formance, an organizational model composed of individual models of a five stage interacting decision maker was designed using an object oriented design approach and implemented as a Colored Petri net. The concept of entropy is used to calculate the total activity value, a surrogate for decision maker workload, based on the functional partition and the adaptation strategy being implemented. The individual decision maker’s total activity is monitored, as overloaded decision makers constrain organizational performance. A virtual experiment was conducted; organizations implementing local and global adaptation strategies were compared to a control organization with no adaptation. The level of tolerance of the organization, the workload limit based on the concept of the bounded rationality constraint, was used to determined when a decision maker was overloaded: the limiting effect of theworkload on performance. The timeliness of the organization’s responsewas used in order to evaluate organizational output as a function of adaptation strategy

Levels of Interoperability in Coalition Systems

Systems of different command centers that are brought together in a coalition operation must have some level of interoperability in order to work together. Bares [2000] has introduced a formalism of three interoperability domains that describe the ability of the systems to define their own level of interoperability within the coalition by assessing their own and the other systems’ ability to interact on actions of the coalition. The lowest domain, interconnectivity, reflects the ability to exchange messages; this level must already have been achieved in order for the systems to participate in the coalition. The second domain, interoperability, reflects a system’s ability to identify what tasks it is able to interoperate on. The third level, intercooperability, indicates that all systems have the ability to evaluate all other systems in the coalition. By describing the interoperability domains in this manner, the domains represent increasing levels of awareness of each system’s own capabilities and those of the other systems; it represents the transition from exchanging data to exchanging knowledge. This research looks particularly at the interoperability level and the ability of systems to evaluate their own interoperability on the coalition’s actions by using Bares’ formalism of interoperability to assign actions to systems participating in the coalition

Continuity in Dynamic Coalition Operations

The combination of participating organizations in a coalition operation often changes over time; the coalition is dynamic and evolves over the course of its mission. A given organization may participate in the coalition only at the stage where its expertise or resources are most needed, while other organizations may participate through the entire course of the operation. As these are independent organizations coming together for a limited time to meet a specific goal, the structure of the coalition must be able to accommodate the different command arrangements, procedures, and other characteristics of each organization. In order to develop a theory of a coalition structure that can accommodate the changing needs of the coalition, a dynamic model of a coalition is being developed that allows organizational participation to fluctuate over the course of the mission. In order to ensure that the model emulates real world situations, a scenario was created from actual coalition experiences in the NATO-led Balkan’s peacekeeping operations in Kosovo, where lead nations were assigned under the operational command of the NATO-led force. Adding to the complexity of the operations was the fact that military commanders and staff turned over frequently creating stability and continuity of operations challenges. This project attempts to capture some of these dynamics in order to draw conclusions about the effect of change on the coalition structure

A phase 1/2 study of the oral FLT3 inhibitor pexidartinib in relapsed/refractory FLT3-ITD-mutant acute myeloid leukemia.

FMS-like tyrosine kinase 3 (FLT3) tyrosine kinase inhibitors (TKIs) have activity in acute myeloid leukemia (AML) patients with FLT3 internal tandem duplication (ITD) mutations, but efficacy is limited by resistance-conferring kinase domain mutations. This phase 1/2 study evaluated the safety, tolerability, and efficacy of the oral FLT3 inhibitor PLX3397 (pexidartinib), which has activity against the FLT3 TKI-resistant F691L gatekeeper mutation in relapsed/refractory FLT3-ITD-mutant AML. Ninety patients were treated: 34 in dose escalation (part 1) and 56 in dose expansion (part 2). Doses of 800 to 5000 mg per day in divided doses were tested. No maximally tolerated dose was reached. Plasma inhibitory assay demonstrated that patients dosed with ≥3000 mg had sufficient levels of active drug in their trough plasma samples to achieve 95% inhibition of FLT3 phosphorylation in an FLT3-ITD AML cell line. Based on a plateau in drug exposure, the 3000-mg dose was chosen as the recommended phase 2 dose. The most frequently reported treatment-emergent adverse events were diarrhea (50%), fatigue (47%), and nausea (46%). Based on modified response criteria, the overall response rate to pexidartinib among all patients was 21%. Twenty-three percent of patients treated at ≥2000 mg responded. The overall composite complete response rate for the study was 11%. Six patients were successfully bridged to transplantation. Median overall survival (OS) of patients treated in dose expansion was 112 days (90% confidence interval [CI], 77-150 days), and median OS of responders with complete remission with or without recovery of blood counts was 265 days (90% CI, 170-422 days). This trial was registered at www.clinicaltrials.gov as #NCT01349049

Using Optimal Test Assembly Methods for Shortening Patientâ Reported Outcome Measures: Development and Validation of the Cochin Hand Function Scaleâ 6: A Scleroderma Patientâ Centered Intervention Network Cohort Study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134498/1/acr22893_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134498/2/acr22893.pd

A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios

A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows

We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT