Performance Engineering

This paper describes the development of a methodology to import key products of the DoD Architecture Framework into an executable form to conduct a dynamic analysis of the Command and Control (C2) system or capability represented by the architecture. Dynamic analysis of these models enables a user to assess the impact of change and determine measures of performance and effectiveness. The research team successfully implemented the methodology in a demonstration that made a three-way link among a business process model, a communications network model, and a combat simulation representing the system's operational environment. We linked these models together via the Runtime Infrastructure (RTI) of the High Level Architecture (HLA). Basic HLA interactions that we established allowed key events in the combat simulation to initiate one or more business processes in the process model. As a business process proceeded in time, the process model requested from the communications model a de...

The object of this work is the investigation of new locally swept grid fins (lattice wings) regarding its potential of the performance improvement at high speeds. Detailed examinations include numerical simulations of the supersonic flow around the conventional and locally swept planar and lattice wings of infinite span as well as direct force measurements at corresponding realistic finite span models in the Ludwieg Tube Facility at DLR (RWG). The investigations were performed at free-stream Mach numbers from 2 to 6 for angles of attack varied from 0 to 10 degrees. The performance of the lattice wings was assessed on the basis of the zero-lift drag and lift-to-drag ratio, both the major parameters in wing design. The numerical and experimental results show that the novel design of the lattice wings has distinct advantages in comparison to the conventional not-swept configurations. Compared to conventional lattice wings the maximum benefit e.g. of the zero-lift total drag for the inv...

: This report summarizes the results of a two year project led by the Naval Facilities Engineering and ExpeditionaryWarfare Center to demonstrate the potential for the patented I2 infusion system to reduce the rate of foul within Department of Defense shipboard heat exchangers. Fouling of DoD shipboard heat exchangers is a chronic and costly operating problem that requires significant maintenance. The heat transfer performance and efficiency decreases due to the fouling of the heat exchanger plates and tubes resulting in additional fuel consumption and increased greenhouse gases. Costly and labor consuming, remedial chemical cleaning protocols currently used produce considerable hazardous waste. Through the infusion of air containing elemental iodine vapor into the heat exchanger, this demonstration has shown that the formation of biological foul has been reduced and the period between physical cleanings extended while maintaining acceptable system parameters.

This paper describes an algorithm for distributed acoustic navigation for Autonomous Underwater Vehicles (AUVs). Whereas typical AUV navigation systems utilize pre-calibrated arrays of static transponders, our work seeks to create a fully mobile network of AUVs that perform acoustic ranging and data exchange with one another to achieve cooperative positioning for extended duration missions over large areas. The algorithm enumerates possible solutions for the AUV trajectory based on dead-reckoning and range-only measurements provided by acoustic modems that are mounted on each vehicle, and chooses the trajectory via minimization of a cost function based on these constraints. The resulting algorithm is computationally efficient, meets the strict bandwidth requirements of available AUV modems, and has potential to scale well to networks of large numbers of vehicles. The method has undergone extensive experimentation, and results from three different scenarios are reported in this paper...

Constructed system with autonomy can be considered as possessing intelligence, if intelligence is understood as a metaphor. It is useful to be aware of that, when defining desirable features for constructed systems, in areas such as reflecting the world (ontology), definition and pursuit of goals (teleology), or general human-like behavior (anthropomorphism). Modeling and simulating integrated systems exemplify the usage of multi-scale, multi-disciplinary representations, as a basis for increasing the autonomy of some specific constructed systems. Measuring the intelligence of constructed systems requires a Vector of Metrics for Intelligence. Its components will be defined by different means, such as conducting existence tests for essential capabilities, measuring the power to eliminate unnecessary exploration, competitions of hardware-compatible systems, or vote by a jury.

The problem of large-area coverage with a distributed set of short-range proximity sensors is investigated analytically. Analysis of the design tradeoffs between sensor range, sensor detection performance, and sensor false alarm performance is presented relative to the density of sensors in the field. Additionally, the impact of non-uniformity in sensor distribution on these performance assessments is quantified. The use of both individual sensor detections and coupled groups of sensor detections as a basic track-determination strategy is examined. Finally, guidance is included on strategies for making sound engineering tradeoffs based on the analytical results.

This position paper brings together the evaluation of ambient intelligence architectures in context-awareness systems with performance modeling. Thus, firstly appropriate description methods for distributed intelligent applications are summarized. Derived from the system characterization, typical software performance engineering techniques are based on the augmented description of the model regarding performance annotations. However, these annotations are only related with the syntactical view

A central problem in multistrategy learning systems is the selection and sequencing of machine learning algorithms for particular situations. This is typically done by the system designer who analyzes the learning task and implements the appropriate algorithm or sequence of ...

This paper describes the conceptual framework, development process, and theoretical structure for an online performance tracking system. The principle factors influencing online performance tracking are described using the weighted sum model as computational method on measures of performance. Input data for the computational model were obtained directly from a real-time system in an actual organization that directly measured staff performance. In this multicriteria decision-making approach, the criteria weights are computed using the entropy information method and ranking of 15 alternatives (employees) is computed using the weighted sum model. Computational results obtained using the online performance appraisal system are evaluated and discussed relative to the weighted sum model.

Abstract : Lessons 21 will present the big picture of systems acquisition as well as the specific contributions made by the Human Factors Engineering (HFE) community to the acquisition process. The human engineer is fundamentally concerned with making sure that the best possible designs are provided within the constraints of time, money, and technical capability. The level of human factors input to systems acquisition is not determined by the cost of the system alone, but by the extent to which the system needs to be human engineered. Lesson 22 will define exactly what systems analysis means and show why knowledge of it is so important to a human factors specialist. It will also introduce some of the more common techniques used when conducting a system analysis. In addition, some of the road blocks that can be expected to be encountered will be presented along with ways to avoid. them. The purposes of systems analysis can be neatly packaged into five general areas: Scheduling, Identifyilng limilting factors, Establishing system performance criteria, Identifying and explaining various design options, Evaluating systems. Lesson 23 will present the history of task analysis, what its aims are, what factors go into a task analysis, and the uses of task analysis. Lessons 24 of the Human Factors Engineering Course will finish the topic of task analysis. One of the purposes of task analysis is to ensure that all the human performance requirements for a new man-machine system have been identified. Lessons 25 will discuss some of the practical issues that arise in cost/benefit trade-offs. This lesson should provide some insights into an important area where system and task analysis skills are typically put to use.

Objective: We evaluate and quantify the effects of human, robot, and environmental factors on perceived trust in human-robot interaction (HRI). Background: To date, reviews of trust in HRI have been qualitative or descriptive. Our quantitative review provides a fundamental empirical foundation to advance both theory and practice. Method: Meta-analytic methods were applied to the available literature on trust and HRI. A total of 29 empirical studies were collected, of which 10 met the selection criteria for correlational analysis and 11 for experimental analysis. These studies provided 69 correlational and 47 experimental effect sizes. Results: The overall correlational effect size for trust was r̄ = +0.26, with an experimental effect size of d̄ = +0.71. The effects of human, robot, and environmental characteristics were examined with an especial evaluation of the robot dimensions of performance and attribute-based factors. The robot performance and attributes were the largest contri...

Symbolic model checking is a successful technique for checking properties of large finite-state systems. This method has been used to verify a number of real-world hardware designs; however it is not able to determine timing or performance properties directly. ...