Afreen Siddiqi

Flexible and reconfigurable systems: Nomenclature and review

The demands on today’s products have become increasingly complex as customers expect enhanced performance across a variety of diverse and changing system operating conditions. Reconfigurable systems are capable of undergoing changes in order to meet new objectives, function effectively in varying operating environments, and deliver value in dynamic market conditions. Research in the design of such responsive and changeable systems, however, currently faces impediments in effective and clear discourse due to ambiguity in terminology. Definitions of the terms flexibility and reconfigurability, two related concepts in reconfigurable system design, are explored based on their original lexical meanings and current understanding in design literature. Design techniques that incorporate flexibility both in the design (form) and performance (function) space are presented. Based upon this literature survey, a classification scheme for flexibility is proposed, and its application to reconfigurable system design is explored. This paper also presents recent methodologies for reconfigurable system design and poses important research questions that remain to be investigated.

Modeling Methods and Conceptual Design Principles for Reconfigurable Systems

Reconfigurable systems can attain different configurations at different times thereby altering their functional abilities. Such systems are particularly suitable for specific classes of applications in which their ability to undergo changes easily can be exploited to fulfill new demands, allow for evolution, and improve survivability. This paper identifies the main factors that drive the need for reconfigurability and proposes methods for modeling reconfigurable systems. A survey of 33 different reconfigurable systems is also presented to provide broader insights and general design guidelines for reconfigurable systems.

Hierarchical Decomposition and Multidomain Formulation for the Design of Complex Sustainable Systems

Designing a large-scale complex system, such as a city of the future, with a focus on sustainability requires a systematic approach toward integrated design of all subsystems. Domains such as buildings, transportation, energy, and water are all coupled. Designing each one in isolation can lead to suboptimality where sustainability is achieved in one aspect but at the expense of other aspects. Traditional ad hoc allocations of design parameter precedence and dependence cannot be used for cases where new (instead of only mature) architectures are to be explored. A methodology is introduced for addressing design problems of complex sustainable systems that is comprised of, on the one hand, a hierarchical decomposition that includes multilevel abstraction and design parameter identification, and on the other hand, a multidomain formulation, which includes parameter dependency identification, design cycle identification and decision structuring, and scoping. The application of the methodology for the design of a new urban development, Masdar City in Abu Dhabi, with over 220 different form and behavior parameter sets is shown.

Achieving Sustainable Development Goals from a Water Perspective

Efforts to meet human water needs only at local scales may cause negative environmental externality and stress on the water system at regional and global scales. Hence, assessing SDG targets requires a broad and in-depth knowledge of the global to local dynamics of water availability and use. Further, Interconnection and trade-offs between different SDG targets may lead to sub-optimal or even adverse outcome if the set of actions are not properly pre-designed considering such interlinkages. Thus scientific research and evidence have a role to play in facilitating the implementation of SDGs through assessments and policy engagement from global to local scales. The paper addresses some of these challenges related to implementation and monitoring the targets of the Sustainable Development Goals from a water perspective, based on the key findings of a conference organised in 2015 with the focus on three essential aspects of SDGs- indicators, interlinkages and implementation. The paper discusses that indicators should not be too simple but ultimately deliver sustainability measures. The paper finds that remote sensing and earth observation technologies can play a key role in supporting the monitoring of water targets. It also recognises that implementing SDGs is a societal process of development, and there is need to link how SDGs relate to public benefits and communicate this to the broader public.

Energy use in large-scale irrigated agriculture in the Punjab province of Pakistan

Pakistan’s Indus Basin irrigation system, conceived initially as a vast network of gravity-fed canals, has evolved into a quasi-conjunctive management system in which pumped groundwater increasingly augments surface water supplies. Analysis of the evolution of on-farm energy use for agriculture in Punjab Province over the last 15 years finds that while total crop production increased 31%, direct energy intensity for agriculture increased 80%. Moreover, direct energy use is chiefly driven by groundwater pumping (61%). Important knowledge gaps are identified in the critical water-energy-food interdependencies that need to be addressed for sustainable management of scarce natural resources in Pakistan.

A Posteriori Design Change Analysis for Complex Engineering Projects

Engineering changes are an inherent part of the design and development process and can play an important role in driving the overall success of the system. This work seeks to create a multidimensional understanding of change activity in large systems that can help in improving future design and development efforts. This is achieved by a posteriori analysis of design changes. It is proposed that by constructing a temporal, spatial, and financial view of change activity within and across these dimensions, it becomes possible to gain useful insights regarding the system of study. Engineering change data from the design and development of a multiyear, multibillion dollar development project of an offshore oil and gas production system is used as a case study in this work. It is shown that the results from such an analysis can be used for identifying better design and management strategies (in similar systems and projects) and for targeting design improvement in identified subsystems. The isolation and identification of change hotspots can be helpful in uncovering potential systemic design issues that may be prevalent. Similarly, strategic engineering and management decisions can be made if the major cost drivers are known.

Matrix Modeling Methods for Spaceflight Campaign Logistics Analysis

This paper proposes amatrix-basedmodeling approach for analyzing spaceflight campaign logistics. A campaign is considered to be a series of coordinatedflights delivering cargo at a location or node. Amatrix representation of the cargo carried by flights for consumption in different time periods (or missions) is formulated. The matrix adopts specific structures based on the nature of the campaign, thereby allowing a quick visualization of the campaign logistics properties. A logistics strategy index is proposed for quantifying manifesting strategies, and a flight criticality index is defined to help in identifying important flights from a cargo-delivery perspective and aid in assessing impact of flight cancellations, failures, and delays. The method is demonstrated on a lunar outpost establishment and is also applied in modeling the logistics of the International Space Station. Amanifest (M) matrix and flight dependency (D) matrix is created for crew provisions cargo delivered to the ISS over a period of 10 years. It is found that the overall logistics strategy index for crew provisions has so far been 0.85 (meaning 85% of the crew provisions cargo is prepositioned on average for each mission) and that the prepositioning is for up to a maximum of four future missions at a time.

The Future of Asset Management for Human Space Exploration: Supply Classification and an Integrated Database

One of the major logistical challenges in human space exploration is asset management. This paper presents observations on the practice of asset management in support of human space flight to date and discusses a functional-based supply classification and a framework for an integrated database that could be used to improve asset management and logistics for future human missions to the Moon, Mars and beyond.

A flexible architecture and object-oriented model for space logistics simulation

This paper summarizes the motivation for and the resulting development of a flexible object-oriented software model for simulation and analysis of space exploration campaign logistics. The software model was designed to be applicable to several widely-varying use case scenarios including International Space St ation resupply, support for a long-term lunar outpost and global lunar exploration, and Martian exploration by human and robotic agents. The model includes analysis capability fo r exploration sustainability topics including reusability, reconfigurability, commonality, and repairability. Key additional features include modular demand models that are easily interchanged, element-level models for finegrained demand integration, and reconfigurable system operational states to dynamically change demand models. Other capabilities include generalized impulsive burn maneuvers, surface transportation, abstracted flight transportation, improved support for multidestination scenarios, and multi-user collaboration via online databases.

SpaceNet: Modeling and Simulating Space Logistics

This paper summarizes the current state of the art in interplanetary supply chain modeling and discusses SpaceNet as one particular method and tool to address space logistics modeling and simulation challenges. Fundamental upgrades to the interplanetary supply chain framework such as process groups, nested elements, and cargo sharing, enabled SpaceNet to model an integrated set of missions as a campaign. The capabilities and uses of SpaceNet are demonstrated by a step-by-step modeling and simulation of a lunar campaign.