Understanding Resilience Optimization Architectures With an Optimization Problem Repository

2021 ◽  
Author(s):  
Daniel Hulse ◽  
Hongyang Zhang ◽  
Christopher Hoyle
Keyword(s):  
Optimization Problem ◽  
Optimization Problems ◽  
Health Management ◽  
Single Case ◽  
Decomposition Strategies ◽  
Prevention Model ◽  
System Resilience ◽  
Pandemic Response ◽  
Upper Level

Abstract Optimizing a system’s resilience can be challenging, especially when it involves considering both the inherent resilience of a robust design and the active resilience of a health management system to a set of computationally-expensive hazard simulations. While prior work has developed specialized architectures to effectively and efficiently solve combined design and resilience optimization problems, the comparison of these architectures has been limited to a single case study. To further study resilience optimization formulations, this work develops a problem repository which includes previously-developed resilience optimization problems and additional problems presented in this work: a notional system resilience model, a pandemic response model, and a cooling tank hazard prevention model. This work then uses models in the repository at large to understand the characteristics of resilience optimization problems and study the applicability of optimization architectures and decomposition strategies. Based on the comparisons in the repository, applying an optimization architecture effectively requires understanding the alignment and coupling relationships between the design and resilience models, as well as the efficiency characteristics of the algorithms. While alignment determines the necessity of a surrogate of resilience cost in the upper-level design problem, coupling determines the overall applicability of a sequential, alternating, or bilevel structure. Additionally, the application of decomposition strategies is dependent on there being limited interactions between variable sets, which often does not hold when a resilience policy is parameterized in terms of actions to take in hazardous model states rather than specific given scenarios.

Multi-Objective Robust Optimization Under Interval Uncertainty Using Online Approximation and Constraint Cuts

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
W. Hu ◽  
M. Li ◽  
S. Azarm ◽  
A. Almansoori
Keyword(s):  
Optimization Problem ◽  
Optimization Problems ◽  
Computational Effort ◽  
Interval Uncertainty ◽  
Test Results ◽  
Robust Solution ◽  
Multi Objective ◽  
Function Calls ◽  
Level Problem ◽  
Upper Level

Many engineering optimization problems are multi-objective, constrained and have uncertainty in their inputs. For such problems it is desirable to obtain solutions that are multi-objectively optimum and robust. A robust solution is one that as a result of input uncertainty has variations in its objective and constraint functions which are within an acceptable range. This paper presents a new approximation-assisted MORO (AA-MORO) technique with interval uncertainty. The technique is a significant improvement, in terms of computational effort, over previously reported MORO techniques. AA-MORO includes an upper-level problem that solves a multi-objective optimization problem whose feasible domain is iteratively restricted by constraint cuts determined by a lower-level optimization problem. AA-MORO also includes an online approximation wherein optimal solutions from the upper- and lower-level optimization problems are used to iteratively improve an approximation to the objective and constraint functions. Several examples are used to test the proposed technique. The test results show that the proposed AA-MORO reasonably approximates solutions obtained from previous MORO approaches while its computational effort, in terms of the number of function calls, is significantly reduced compared to the previous approaches.

scholarly journals Proximal Gradient Method for Solving Bilevel Optimization Problems

2020 ◽  
Vol 25 (4) ◽  
pp. 66
Author(s):  
Seifu Endris Yimer ◽  
Poom Kumam ◽  
Anteneh Getachew Gebrie
Keyword(s):  
Optimization Problem ◽  
Optimization Problems ◽  
Gradient Methods ◽  
Split Feasibility Problem ◽  
Bilevel Optimization ◽  
Feasibility Problem ◽  
Proximal Gradient Method ◽  
Level Problem ◽  
Upper Level ◽  
The Split Feasibility Problem

In this paper, we consider a bilevel optimization problem as a task of finding the optimum of the upper-level problem subject to the solution set of the split feasibility problem of fixed point problems and optimization problems. Based on proximal and gradient methods, we propose a strongly convergent iterative algorithm with an inertia effect solving the bilevel optimization problem under our consideration. Furthermore, we present a numerical example of our algorithm to illustrate its applicability.

scholarly journals Two-Level Planning of Customized Bus Routes Based on Uncertainty Theory

2021 ◽  
Vol 13 (20) ◽  
pp. 11418
Author(s):  
Bing Zhang ◽  
Zhishan Zhong ◽  
Zi Sang ◽  
Mingyang Zhang ◽  
Yunqiang Xue
Keyword(s):  
Uncertainty Theory ◽  
Optimization Problem ◽  
Operating Time ◽  
Route Planning ◽  
Theoretical Support ◽  
Level Model ◽  
Upper Level ◽  
Bus Route Planning ◽  
Two Level Model

The optimization problem of customized bus routes is affected by uncertain factors in reality; therefore, this paper introduces uncertainty theory to study the above problem. A two-level planning model that takes the maximum total revenue of the bus company as the upper-level goal and the minimum total travel cost of passengers as the lower-level goal is established, using uncertainty theory to study and solve practical problems with uncertain factors. The genetic algorithm is used to solve the model, and the feasibility of the model is verified through a case study. The research results show that the application of the two-level model of customized bus route planning based on uncertain vehicle operating time established in this paper to customize bus route planning can take into account the travel needs of passengers and high-quality experiences while also bringing benefits to enterprises and achieving a win–win situation. The research in this article provides theoretical support for the optimization of customized bus routes.

Who Has Potatoes?

2003 ◽  
Vol 1 (2) ◽  
pp. 148-159
Author(s):  
Keith V. Bletzer
Keyword(s):  
Substance Use ◽  
Home Country ◽  
Single Case ◽  
Turning Points ◽  
Farm Labor ◽  
Single Case Study ◽  
Long Period ◽  
Migrant Work

Migratory farm labor like other forms of migrant work both in and outside agriculture impedes on the opportunity to make choices. The following essay explores particular phases in the life of one man (a single case study) and examines how he considers turning points in his life that led to a long period of substance use, both as an immigrant in the country and as a working man in his home country, followed by a cessation of use and the beginning stages of recovery. / Para el migrante, viajar en busca de trabajo es díficil, ya sea que trabaje en agricultura o en otras labores. Este ensayo examina ciertas etapas en la vida de un hombre (estudio de un solo caso) que examina los cambios que le han ocurrido durante un período en que él consumía grandes cantidades de alcohol en los estados y en su país, seguido por un período de sobriedad (no tomaba alcohol, no usaba drogas) en este país en que él comienza una etapa de rehabilitación.

Contamination Lab of Turin (CLabTo)

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Eleonora FIORE ◽  
Giuliano SANSONE ◽  
Chiara Lorenza REMONDINO ◽  
Paolo Marco TAMBORRINI
Keyword(s):  
University Students ◽  
Single Case ◽  
Real Life ◽  
Learning By Doing ◽  
Assessment Data ◽  
Entrepreneurial Skills ◽  
Fields Of Study ◽  
Education Levels ◽  
Positive Effect

Interest in offering Entrepreneurship Education (EE) to all kinds of university students is increasing. Therefore, universities are increasing the number of entrepreneurship courses intended for students from different fields of study and with different education levels. Through a single case study of the Contamination Lab of Turin (CLabTo), we suggest how EE may be taught to all kinds of university students. We have combined design methods with EE to create a practical-oriented entrepreneurship course which allows students to work in transdisciplinary teams through a learning-by-doing approach on real-life projects. Professors from different departments have been included to create a multidisciplinary environment. We have drawn on programme assessment data, including pre- and post-surveys. Overall, we have found a positive effect of the programme on the students’ entrepreneurial skills. However, when the data was broken down according to the students’ fields of study and education levels, mixed results emerged.

Business Incubation in Uganda, Services, Processes and Incubatee Perceptions- A case study

10.33117/514 ◽  
2017 ◽  
Vol 13 (1) ◽  
pp. 94-108
Keyword(s):  
Social Enterprise ◽  
Single Case ◽  
Business Incubation ◽  
Entrepreneurial Networks ◽  
Private Sector Development ◽  
Statistical Inferences ◽  
Office Space ◽  
Interview Methods ◽  
Entrepreneurial Training

Purpose-This paper examines the nature of services and processes of business incubation. Its specific objectives are to establish the nature of services offered by business incubation centers in Uganda, examine the incubation process and to establish the perception of business incu- batees about business incubation services using a case of FinAfrica a private social enterprise. Methodology-This paper presents findings from one incubation center FinAfrica as a case study. Ethnographic design is adopted while observation and interview methods are used to collect data. Results-Key services offered by FinAfrica incubation center include entrepreneurial training, provision of office space, legal and accounting services, mentoring, coaching, entrepreneurial networks and general office administration. The centre has a unique business incubation model which starts with motivating people to start businesses, capacity building, business registration, and ends with graduation after attaining capability for self-sustainability. Incubatees perceive the services offered by the incubation centre as helpful through training, affordable office space, entrepreneurial ecosystem and opportunities for a lean startup. Implications- While this study does not offer statistical inferences for generalisation because of the qualitative design and single case, the exploration of FinAfrica provides insights about how Incubation centers need to plan for positive and sustainable entrepreneurial impact for startups. There is need for more Government and other development partners’ involvement in business incubation and post incubation support for competiveness and growth. Originality/value- This study provides insights about the key services offered in the incubation process and provides insights into the perceived benefits of business incubation. It also contributes to literature about business incubation with practical evidence from an emerging economy whose focus is on private sector development and innovation promotion.

Sign in / Sign up

Export Citation Format

Share Document