Shashank Tamaskar

Complexity enabled design space exploration

The proposed paper presents a framework for complexity enabled design space exploration. A circuit problem is introduced where different designs are generated from a component library to create a low pass filter circuit. Performance and complexity metrics are defined to measure the fitness of the design. A scheme for complexity enabled design space exploration is introduced and the results obtained are compared to the traditional performance based exploration. It is found that the complexity enabled exploration results in identification of regions within the performance-complexity trade space which are difficult to obtain using a performance based exploration. Characteristic features of designs that result in high performance but low complexity are also identified. Later a scheme for local design space exploration is proposed which investigates the designs in the nearest neighborhood of a particular design. This provides insights about the flexibility and adaptability of the design.

Investigation of Connectivity: Definition, Application, and Formulation

In this paper, we will investigate the nature of connectivity in the air transportation network. We will review definitions of air connectivity from previous literature, and based on these definitions establish a set of criteria by which to measure the quality of a connectivity metric. We will provide results of experimentation with one connectivity metric, the Air Connectivity Index, on several networks. Through this experimentation, we will explore methodological issues and areas for improvement. We will examine the use of formal and informal procedures to establish a better connectivity metric based on the quality criteria. Formal procedures may include comparing the goodness of fit of different estimators, while informal procedures may include measuring the intuitiveness of a connectivity ranking.

Innovative Framework for Orbital Debris Mitigation through Satellite Rejuvenation

This paper presents a conceptual framework for orbital debris mitigation through satellite rejuvenation. Instead of developing complex robotic technologies, the concept focuses on relatively simple use of inspection and rejuvenation module designs. Our approach would inspect the dysfunctional satellite, and rejuvenate it if it is found to be serviceable. Otherwise, the approach would deorbit the dysfunctional satellite. Though only described in this paper as a concept, a review of the state of the art indicates that the concept could be advantageous to mitiage orbital debris. I. Introduction PACE systems operate in a harsh and hostile environment. Following launch, there is little flexibility to modify any aspect of their operation with the exception of software updates via uplink. This inaccessibility makes them susceptible to technological obsolescence and failures. Historical analysis indicates that approximately one out of every seven satellites launched fail before reaching their end of life (EOL). Some of these failures result from malfunction of the launch vehicle, which can either cause complete destruction of the satellite or lead to the satellite being placed in the wrong orbit. Other reasons for failures stem from breakdown of one or more components during their operation or due to collision with space debris. With each satellite costing hundreds of millions of dollars and huge capital investment involved in space missions, the space industry today has become extremely averse to risks. This environment, where cost of failure is unacceptably large, has stifled innovation and has driven space systems design towards use of greater redundancy and proven technology. We propose a unique concept for rejuvenating these defunct satellites which have either reached EOL or failed during the course of its mission. We also investigate the possibility of de-orbiting the defunct satellite in case the satellite is found to be damaged beyond repair. We believe that this will have the following advantages: 1) Greater probability of return on the huge investment involved in developing and launching space missions, 2) Extended design life, 3) Reduce development costs and risks in new satellite designs. These benefits, especially 3, will allow a greater room for innovation and development of better systems. Further, a rejuvenated satellite with regain additional maneuvering capability, thus mitigating potential orbital debris generated from the collision with other orbital debris.

Modularity research to guide MOSA implementation

The US Department of Defense’s acquisition strategy incorporates directives to encourage the use of open architectures and modular solutions through the Modular Open Systems Approach (MOSA). The ways in which open standards are currently implemented, and programmatic guidance regarding the adoption of modular approaches, are inadequate, however, because of limitations on how modularity is objectively viewed to achieve its perceived benefits. Furthermore, current examples of implementations of modular concepts largely do not consider interdependencies at the enterprise level. This paper reviews ongoing research on modularity and openness, to synthesize best practices, community driven knowledge, and technical and programmatic catalysts that can better shape the appropriate adoption of MOSA. These items will be part of a comprehensive decision-making framework that can provide guidance to program managers in defense acquisition.

Consensus Based Operating Picture for Distributed Battlefield Management

Developing a Common Operating Picture (COP) is a key enabler for the success on the modern battlefield. In this paper, we propose a distributed approach for developing a Consensus Based Common Operating Picture (CBCOP) where the participating assets iteratively synchronize their local operating pictures and establish a consensus. This enables generation of a COP in a truly distributed fashion with multiple command and control nodes each having a consistent COP and thereby mitigating some of the issues with centralized COP. The effectiveness of this strategy can only be realized by the development of algorithms for distributed situational awareness and mission planning. Thus we suggest two specific state of art algorithms and demonstrate their effectiveness in generating CBCOP through simulations.

Complexity Analysis of Spacecraft Architectures

In this paper, the authors explore the properties of different spacecraft architectures from the standpoint of system complexity. For this study, three architectures (monolithic, fractionated and modular) are chosen. A hypothetical mission is considered and spacecraft are designed using the three architectures and analyzed with regard to their system and design complexity. We represent each design as a network of component and interactions and measure the complexity of each design using network theory metrics, which show correlation with different aspects of system complexity. In conclusion, we discuss how the design features inherent in the architectures contribute to the system and design complexity.