The Value of Flexible Capacity Expansion Strategies in Design of Complex Decentralized Engineering Systems

2015 ◽  
Author(s):  
Junfei Hu ◽  
Michel-Alexandre Cardin
Keyword(s):  
Economies Of Scale ◽  
Unit Cost ◽  
Waste To Energy ◽  
Small Scale ◽  
Engineering Systems ◽  
Complex Engineered Systems ◽  
Decentralized Design ◽  
Engineered Systems ◽  
Reduce Unit Cost ◽  
Over Time

This paper presents and applies a simulation-based methodology to assess the value of flexible decentralized engineering systems (i.e., the ability to flexibly expand the capacity in multiple sites over time and space). This work differs from others by analyzing explicitly the tradeoffs between economies of scale (EoS) — which favors building large capacity upfront to reduce unit cost and accommodate high anticipated demand — and the time value of money — which favors deferring capacity investments to the future and deploying smaller modules to reduce unit cost. The study aims to identify the best strategies to deploy capacity of complex engineered systems over time and improve their economic lifecycle performance in the face of uncertainty. This study is illustrated using a waste-to-energy system operated in Singapore. The results show that a decentralized design with the real option to expand the capacity in different locations and times improves the expected net present value by more than 20% under the condition of economies of scale α = 0.8 and discount rate λ = 8%, as compared to a fixed centralized design. The results also indicate that a flexible decentralized design outperforms other rigid designs under certain circumstances since it not only reduces transportation costs, but also has the advantage of flexible deployment strategies, such as deferring investment and avoiding unnecessary capacity. The results help designers and managers better compare centralized and decentralized design opportunities and to recognize the value of flexible decentralized designs in small-scale urban environments. The example also provides guidance for applying flexibility to a wider range of complex engineered systems and to determine the best strategies for deploying the capacity of systems in other urban contexts.

scholarly journals Analyzing the Tradeoffs Between Economies of Scale, Time-Value of Money, and Flexibility in Design Under Uncertainty: Study of Centralized Versus Decentralized Waste-to-Energy Systems

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Michel-Alexandre Cardin ◽  
Junfei Hu
Keyword(s):  
Economies Of Scale ◽  
Unit Cost ◽  
Waste To Energy ◽  
Small Scale ◽  
Time Value Of Money ◽  
Time Value ◽  
Decentralized Design ◽  
Reduce Unit Cost ◽  
Value Of Money ◽  
Over Time

This paper presents and applies a simulation-based methodology to assess the value of flexible decentralized engineering systems design (i.e., the ability to flexibly expand the capacity in multiple sites over time and space) under uncertainty. This work differs from others by analyzing explicitly the tradeoffs between economies of scale (EoS)—which favors designing large capacity upfront to reduce unit cost and accommodate high anticipated demand—and the time value of money—which favors deferring capacity investments to the future and deploying smaller modules to reduce unit cost. The study aims to identify the best strategies to design and deploy the capacity of complex engineered systems over time and improve their economic lifecycle performance in the face of uncertainty by exploiting the idea of flexibility. This study is illustrated using a waste-to-energy (WTE) system operated in Singapore. The results show that a decentralized design with the real option to expand the capacity in different locations and times improves the expected net present value (ENPV) by more than 30% under the condition of EoS  α  = 0.8 and discount rate λ   = 8%, as compared to a fixed centralized design. The results also indicate that a flexible decentralized design outperforms other rigid designs under certain circumstances since it not only reduces transportation costs but also takes advantage of flexibility, such as deferring investment and avoiding unnecessary capacity deployment. The modeling framework and results help designers and managers better compare centralized and decentralized design alternatives facing significant uncertainty. The proposed method helps them analyze the value of flexibility (VOF) in small-scale urban environments, while considering explicitly the tradeoffs between EoS and the time-value of money.

Evaluation of System Reconfigurability Based on Usable Excess

2014 ◽  
Author(s):  
Jeffrey D. Allen ◽  
Jason D. Watson ◽  
Christopher A. Mattson ◽  
Scott M. Ferguson
Keyword(s):  
Communication Systems ◽  
Assembly Line ◽  
Assembly Lines ◽  
Automated Assembly ◽  
Complex Engineered Systems ◽  
Future Needs ◽  
Key Factor ◽  
Long Time ◽  
Engineered Systems ◽  
Over Time

The challenge of designing complex engineered systems with long service lives can be daunting. As customer needs change over time, such systems must evolve to meet these needs. This paper presents a method for evaluating the reconfigurability of systems to meet future needs. Specifically we show that excess capability is a key factor in evaluating the reconfigurability of a system to a particular need, and that the overall system reconfigurability is a function of the system’s reconfigurability to all future needs combined. There are many examples of complex engineered systems; for example, aircraft, ships, communication systems, spacecraft and automated assembly lines. These systems cost millions of dollars to design and millions to replicate. They often need to stay in service for a long time. However, this is often limited by an inability to adapt to meet future needs. Using an automated assembly line as an example, we show that system reconfigurability can be modeled as a function of usable excess capability.

The Structure of Vulnerable Nodes in Behavioral Network Models of Complex Engineered Systems

2017 ◽  
Author(s):  
Hannah S. Walsh ◽  
Andy Dong ◽  
Irem Y. Tumer
Keyword(s):  
Network Models ◽  
Design Parameters ◽  
Engineering Systems ◽  
Critical Design ◽  
Complex Engineered Systems ◽  
Design Variables ◽  
Engineered Systems ◽  
Process Controls ◽  
Robustness Metrics

All methods associated with failure analysis attempt to identify critical design variables and parameters such that appropriate process controls can be implemented to detect problems before they occur. This paper introduces a new approach to the identification of critical design variables and parameters through the concept of bridging nodes. Using a network-based perspective in which design parameters and variables are modeled as nodes, results show that vulnerable parameters tend to be bridging nodes, which are nodes that connect two or more groups of nodes that are organized together in order to perform an intended function. This paper extends existing modeling capabilities based upon a behavioral network analysis (BNA) approach and presents empirical results identifying the relationship between bridging nodes and parameter vulnerability as determined by existing, network metric-based methods. These topological network robustness metrics were used to analyze a large number of engineering systems. Bridging nodes are associated with significantly larger changes in network degradation, as measured by these metrics, than non-bridging nodes when subject to attack (p < 0.001). The results indicate the structural role of vulnerable design parameters in a behavioral network.

scholarly journals Inter-Municipal Cooperation in Waste Management: The Case of Poland

2016 ◽  
Vol 35 (2) ◽  
pp. 91-104 ◽  
Author(s):  
Bartłomiej Kołsut
Keyword(s):  
Waste Management ◽  
Economies Of Scale ◽  
Unit Cost ◽  
Legal Framework ◽  
Key Factors ◽  
Institutional Conditions ◽  
The Third ◽  
Reduce Unit Cost ◽  
The Eu

Abstract This article seeks to present the scale of inter-municipal cooperation in waste management in Poland in the light of the role of three key factors of cooperation. The first shows spatial regularities in the distribution of inter-municipal bodies involved in waste management in Poland, both in the system of voivodeships and historical-cultural regions. The second is institutional conditions confirming the scale of the Europeanisation of public policies taking place in Poland. It embraces the implementation of the EU legal framework in the Polish legal system and the cooperative behaviour of municipalities as a result of those changes. The third is a negative verification of the assumptions of the economic theory upholding the role of financial motivation in establishing cooperation (looking for savings and economies of scale to reduce unit cost); the presented results do not corroborate this type of motivation.

Marginal assessment of the cost and benefits of aphasia treatment: Evidence from community-based telerehabilitation treatment for aphasia

2021 ◽  
pp. 1357633X2098277
Author(s):  
Molly Jacobs ◽  
Patrick M Briley ◽  
Heather Harris Wright ◽  
Charles Ellis
Keyword(s):  
Cost Effectiveness ◽  
Economies Of Scale ◽  
Reference Group ◽  
Unit Cost ◽  
Community Based ◽  
Face To Face ◽  
Conduction Aphasia ◽  
Aphasia Treatment ◽  
The Cost ◽  
The Relationship

Introduction Few studies have reported information related to the cost-effectiveness of traditional face-to-face treatments for aphasia. The emergence and demand for telepractice approaches to aphasia treatment has resulted in an urgent need to understand the costs and cost-benefits of this approach. Methods Eighteen stroke survivors with aphasia completed community-based aphasia telerehabilitation treatment, utilizing the Language-Oriented Treatment (LOT) delivered via Webex videoconferencing program. Marginal benefits to treatment were calculated as the change in Western Aphasia Battery-Revised (WAB-R) score pre- and post-treatment and marginal cost of treatment was calculated as the relationship between change in WAB-R aphasia quotient (AQ) and the average cost per treatment. Controlling for demographic variables, Bayesian estimation evaluated the primary contributors to WAB-R change and assessed cost-effectiveness of treatment by aphasia type. Results Thirteen out of 18 participants experienced significant improvement in WAB-R AQ following telerehabilitation delivered therapy. Compared to anomic aphasia (reference group), those with conduction aphasia had relatively similar levels of improvement whereas those with Broca’s aphasia had smaller improvement. Those with global aphasia had the largest improvement. Each one-point of improvement cost between US$89 and US$864 for those who improved (mean = US$200) depending on aphasia type/severity. Discussion Individuals with severe aphasia may have the greatest gains per unit cost from treatment. Both improvement magnitude and the cost per unit of improvement were driven by aphasia type, severity and race. Economies of scale to aphasia treatment–cost may be minimized by treating a variety of types of aphasia at various levels of severity.

scholarly journals Diversity minimization through part combination – a Portuguese railway infrastructure case study

2020 ◽  
Vol 7 (1) ◽  
pp. 86-94
Author(s):  
Diogo Rechena ◽  
Luís Sousa ◽  
Virgínia Infante ◽  
Elsa Henriques
Keyword(s):  
Economies Of Scale ◽  
Product Family ◽  
Cost Effective ◽  
Added Value ◽  
Small Scale ◽  
Railway Infrastructure ◽  
Sustainable Services ◽  
Market Needs ◽  
Design Diversity ◽  
Requirement Changes

Abstract With increasing market needs for product and service variety, companies struggle to provide diversity in cost-effective ways. Through standardization of components with a low perceived added value, companies can take advantage of economies of scale while maintaining product diversity. Railway infrastructure managers face similar challenges of providing economically sustainable services while dealing with the costs of maintaining the system diversity. Typically, unintended design diversity stems from design practices in which existing solutions are not reused for new problems and new solutions are rarely planned considering the dynamics of requirement changes. In this paper we provide a methodology to assess how to standardize different designs to minimize design diversity and to assess design divergence in a product family. The developed methodology is able to take into account any set of standardization compatibility constraints that the user can define. The methodology was applied in the context of a small-scale railway infrastructure manager using a dataset of 223 unique designs of functionally similar components from its electrification system. Depending on the activated compatibility constraints, results indicate that over 60% of components can be reduced to a set of 86 unique designs.

Integrated Process for Textile Cotton Waste (TCW) Valorization: Waste-to-Energy and Wastewater Decontamination

2016 ◽  
Author(s):  
A. Ribeiro ◽  
C. Vilarinho ◽  
J. Araújo ◽  
J. Carvalho
Keyword(s):  
Raw Materials ◽  
Removal Rate ◽  
Low Cost ◽  
Calorific Value ◽  
Waste To Energy ◽  
Synthetic Wastewater ◽  
Small Scale ◽  
World Population ◽  
Cotton Waste ◽  
Textile Industries

The increasing of world population, industrialization and global consuming, existing market products existed in the along with diversification of raw materials, are responsible for an exponential increase of wastes. This scenario represents loss of resources and ultimately causes air, soils and water pollution. Therefore, proper waste management is currently one of the major challenges faced by modern societies. Textile industries represents, in Portugal, almost 10% of total productive transforming sector and 19% of total employments in the sector composed by almost 7.000 companies. One of the main environmental problems of textile industries is the production of significant quantities of wastes from its different processing steps. According to the Portuguese Institute of Statistics (INE) these industries produce almost 500.000 tons of wastes each year, with the textile cotton waste (TCW) being the most expressive. It was estimated that 4.000 tons of TCW are produced each year in Portugal. In this work an integrated TCW valorisation procedure was evaluated, firstly by its thermal and energetic valorisation with slow pyrolysis followed by the utilization of biochar by-product, in lead and chromium synthetic wastewater decontamination. Pyrolysis experiments were conducted in a small scale rotating pyrolysis reactor with 0.1 m3 of total capacity. Results of pyrolysis experiments showed the formation of 0,241 m3 of biogas for each kilogram of TCW. Results also demonstrated that the biogas is mostly composed by hydrogen (22%), methane (14 %), carbon monoxide (20%) and carbon dioxide (12%), which represents a total high calorific value of 12.3 MJ/Nm3. Regarding biochar, results of elemental analysis demonstrated a high percentage of carbon driving its use as low cost adsorbent. Adsorption experiments were conducted with lead and chromium synthetic wastewaters (25, 50 and 100 mg L−1) in batch vessels with controlled pH. It was evaluated the behaviour of adsorption capacity and removal rate of each metal during 120 minutes of contact time using 5, 10 and 50 g L−1 of adsorbent dosage. Results indicated high affinity of adsorbent with each tested metal with 78% of removal rate in chromium and 95% in lead experiments. This suggests that biochar from TCW pyrolysis may be appropriated to wastewaters treatment, with high contents of heavy metals and it can be an effective alternative to activated carbon.

scholarly journals ECONOMIES OF SCALE IN BANKING, CONFIDENCE SHOCKS, AND BUSINESS CYCLES

2013 ◽  
Vol 18 (5) ◽  
pp. 1069-1090 ◽  
Author(s):  
Scott J. Dressler ◽  
Erasmus K. Kersting
Keyword(s):  
Business Cycles ◽  
Business Cycle ◽  
Economies Of Scale ◽  
Financial Intermediation ◽  
Monetary Shocks ◽  
Nominal Rigidities ◽  
Equilibrium Indeterminacy ◽  
Economic Volatility ◽  
Over Time

Equilibrium indeterminacy due to economies of scale (ES) in financial intermediation is quantitatively examined in a monetary business-cycle environment. Financial intermediation provides deposits that serve as a substitute for currency to purchase consumption, and depositing decisions are susceptible to nonfundamental shocks to confidence. The analysis considers various assumptions on nominal rigidities and the timing of deposit decisions. The results suggest that indeterminacy arises for small ES, and the resulting confidence shocks qualitatively mimic monetary shocks. A calibration exercise concludes that U.S. economic volatility from this nonfundamental source has increased over time while volatility from fundamental sources has decreased.

scholarly journals Theology at Thresholds: Learning from a Practice ‘In Transition’

2017 ◽  
Vol 4 (1) ◽  
pp. 45-62 ◽  
Author(s):  
Rachel Muers ◽  
Rhiannon Grant
Keyword(s):  
Decision Making ◽  
The Other ◽  
Small Scale ◽  
Theological Ethics ◽  
Reciprocal Influence ◽  
Core Practices ◽  
Recent Developments ◽  
Collective Process ◽  
The One ◽  
Over Time

Recent developments in contemporary theology and theological ethics have directed academic attention to the interrelationships of theological claims, on the one hand, and core community-forming practices, on the other. This article considers the value for theology of attending to practice at the boundaries, the margins, or, as we prefer to express it, the threshold of a community’s institutional or liturgical life. We argue that marginal or threshold practices can offer insights into processes of theological change – and into the mediation between, and reciprocal influence of, ‘church’ and ‘world’. Our discussion focuses on an example from contemporary British Quakerism. ‘Threshing meetings’ are occasions at which an issue can be ‘threshed out’ as part of a collective process of decision-making. Drawing on a 2015 small-scale study (using a survey and focus group) of British Quaker attitudes to and experiences of threshing meetings, set in the wider context of Quaker tradition, we interpret these meetings as a space for working through – in context and over time – tensions within Quaker theology, practice and self-understandings, particularly those that emerge within, and in relation to, core practices of Quaker decision-making.

Handling Multiple Objectives in Decentralized Design

2005 ◽  
Author(s):  
Vincent Chanron ◽  
Kemper Lewis ◽  
Yayoi Murase ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki ◽  
...  
Keyword(s):  
Complex Systems ◽  
Design Solution ◽  
Distributed Environments ◽  
Engineering Systems ◽  
Design Problems ◽  
Design Requirements ◽  
Decentralized Design ◽  
Set Based Design ◽  
Standard Techniques ◽  
Different Parts

Most complex systems, including engineering systems such as cars, airplanes, and satellites, are the results of the interactions of many distinct entities working on different parts of the design. Decentralized systems constitute a special class of design under distributed environments. They are characterized as large and complex systems divided into several smaller entities that have autonomy in local optimization and decision-making. A primary issue in decentralized design processes is to ensure that the designers that are involved in the process converge to a single design solution that is optimal and meets the design requirements, while being acceptable to all the participants. This is made difficult by the strong interdependencies between the designers, which are usually characteristic of such systems. This paper proposes a critical review of standard techniques to modeling and solving decentralized design problems, and shows mathematically the challenges created by having multiobjective subsystems. A method based on set-based design is then proposed to alleviate some of these challenging issues. An illustration of its applicability is given in the form of the design of a space satellite.

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