scholarly journals Acquiring Integer Programs from Data

2019 ◽  
Author(s):  
Mohit Kumar ◽  
Stefano Teso ◽  
Luc De Raedt
Keyword(s):  
Operations Research ◽  
Feasible Solution ◽  
Empirical Evaluation ◽  
Integer Program ◽  
Combinatorial Problems ◽  
Benchmark Problems ◽  
Domain Experts ◽  
Integer Programs ◽  
The Core ◽  
Main Challenge

Integer programming (IP) is widely used within operations research to model and solve complex combinatorial problems such as personnel rostering and assignment problems. Modelling such problems is difficult for non-experts and expensive when hiring domain experts to perform the modelling. For many tasks, however, examples of working solutions are readily available. We propose ARNOLD, an approach that partially automates the modelling step by learning an integer program from example solutions. Contrary to existing alternatives, ARNOLD natively handles multi-dimensional quantities and non-linear operations, which are at the core of IP problems, and it only requires examples of feasible solution. The main challenge is to efficiently explore the space of possible programs. Our approach pairs a general-to-specific traversal strategy with a nested lexicographic ordering in order to prune large portions of the space of candidate constraints while avoiding visiting the same candidate multiple times. Our empirical evaluation shows that ARNOLD can acquire models for a number of realistic benchmark problems

scholarly journals A blackbox yield estimation workflow with Gaussian process regression applied to the design of electromagnetic devices

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mona Fuhrländer ◽  
Sebastian Schöps
Keyword(s):  
Gaussian Process ◽  
Surrogate Model ◽  
Hybrid Approach ◽  
Gaussian Process Regression ◽  
Benchmark Problems ◽  
Yield Estimation ◽  
Electromagnetic Devices ◽  
Main Challenge ◽  
Sample Points ◽  
Stochastic Yield

Abstract In this paper an efficient and reliable method for stochastic yield estimation is presented. Since one main challenge of uncertainty quantification is the computational feasibility, we propose a hybrid approach where most of the Monte Carlo sample points are evaluated with a surrogate model, and only a few sample points are reevaluated with the original high fidelity model. Gaussian process regression is a non-intrusive method which is used to build the surrogate model. Without many prerequisites, this gives us not only an approximation of the function value, but also an error indicator that we can use to decide whether a sample point should be reevaluated or not. For two benchmark problems, a dielectrical waveguide and a lowpass filter, the proposed methods outperform classic approaches.

Migrating Software Towards Mobile Technologies

2021 ◽  
pp. 887-903
Author(s):  
Liliana Maria Favre
Keyword(s):  
Mobile Technologies ◽  
Mobile Platforms ◽  
Business World ◽  
The Core ◽  
Mobile Software ◽  
Main Challenge ◽  
The World ◽  
Cross Platform ◽  
Platform Development ◽  
The Internet Of Things

New paradigms such as pervasive computing, cloud computing, and the internet of things (IoT) are impacting the business world. Smartphones are at the core of these paradigms by allowing us interaction with the world around us. In light of this, it is imperative to migrate a lot of existing non-mobile software to adapt it to the new technological reality. The main challenge to achieve this goal is the proliferation of mobile platforms. An integration of ADM (Architecture Driven Modernization), cross-platform development and formal metamodeling to face this kind of migration is described. The proposal was validated with the migration of object-oriented software to different mobile platforms through the multiplatform language Haxe. A comparison of the approach with traditional migration processes and the description of existing challenges in real projects of the scientific and industrial field are included.

Challenges and Pitfalls in Portal Information Management

2011 ◽  
pp. 118-122
Author(s):  
Fredric Landqvist ◽  
Dick Stenmark
Keyword(s):  
Information Management ◽  
Information Quality ◽  
Travel And Tourism ◽  
Internet Portal ◽  
The Core ◽  
Main Challenge ◽  
Management Perspective ◽  
Content Provision

One major objective for information portals is to provide relevant and timely information to their intended target groups. The main challenge from an information management perspective, however, is that the portal itself does not have full information ownership, and therefore cannot guarantee information quality. Poor information quality severely decreases the actual business value of a portal, but the quality of the portal information is inherited from the underlying sources. The case study we present illustrates the evolution of the Swedish Travel and Tourism Council’s (STTC) national Internet portal through three phases, thereby unmasking some of the core problems in portal information management: information ownership, stakeholder incentives, and clear business roles in the content provision process.

Ontology Based RT-Delphi with Explanation Capabilities

2014 ◽  
Vol 3 (2) ◽  
pp. 57
Author(s):  
Ahmed Omran ◽  
Motaz Khorshid
Keyword(s):  
Food Security ◽  
Knowledge Acquisition ◽  
Real Time ◽  
Case Studies ◽  
Water Security ◽  
Policy Decision ◽  
Decision Makers ◽  
Domain Experts ◽  
The Core ◽  
Delphi Approach

<p>Real-Time (RT) Delphi approach is widely used method for knowledge acquisition process. The current RT-Delphi approach ignores considering the unifying domain concepts and their attributes. This limitation can provide the contradiction of the domain experts' judgments and increasing misunderstandings when talking about specific topics. In addition, the current RT-Delphi ignores the explanation capabilities for consensus results, which it is vital for policy/decision makers to be more confidence. The core of this research is to develop ontology-based RT-Delphi with explanation capabilities. We applied the developed approach in to two crucial important case studies in Egypt, which are food security and water security.</p>

scholarly journals An Integrated Approach for the Operational Design of a Cellular Manufacturing System

2021 ◽  
Vol 40 (2) ◽  
pp. 265-278
Author(s):  
Ayesha Maroof ◽  
Adnan Tariq ◽  
Sahar Noor
Keyword(s):  
Manufacturing System ◽  
Cellular Manufacturing ◽  
Hybrid Genetic Algorithm ◽  
Real Life ◽  
Integrated Approach ◽  
Life Cycles ◽  
Benchmark Problems ◽  
Cellular Manufacturing System ◽  
Machine Grouping ◽  
Main Challenge

Shorter product life cycles, unpredictable demand patterns and the ever-shrinking time to market, have been constantly keeping the manufacturing firms under a lot of pressure. To face these challenges the manufacturing organizations have been shifting to Cellular Manufacturing (CM) due to its benefits of reducing manufacturing costs, increasing flexibility and delivering orders on time. Despite having several benefits, designing a Cellular Manufacturing System (CMS) for a real-life application is a tough ask. The main challenge is the part-machine grouping in cells. It becomes even more challenging when the group scheduling (GS) problem is handled alongside the part-machine clustering. To take up this challenge, an integrated model is developed during this research which handles the machine-part grouping and the GS problems, simultaneously. To optimize the multiple objectives of maximizing Grouping Efficacy (GE) and minimizing Makespan (Cmax), concurrently, a Hybrid Genetic Algorithm (HGA) based approach is developed. The proposed technique is validated through the famous benchmark problems, unlike the several approaches already available in literature. The computational results have shown that the integrated approach, presented in this paper, is more effective as compared to a sequential technique. Also, its accuracy remains intact even if it is applied to large sized problems.

The Quadratic Multiknapsack Problem with Conflicts and Balance Constraints

2020 ◽  
Author(s):  
Philippe Olivier ◽  
Andrea Lodi ◽  
Gilles Pesant
Keyword(s):  
Integer Programming ◽  
Constraint Programming ◽  
Operations Research ◽  
Solution Process ◽  
Exact Method ◽  
The Core ◽  
Computational Evaluation ◽  
Operations Research Applications

The quadratic multiknapsack problem consists of packing a set of items of various weights into knapsacks of limited capacities with profits being associated with pairs of items packed into the same knapsack. This problem has been solved by various heuristics since its inception, and more recently it has also been solved with an exact method. We introduce a generalization of this problem that includes pairwise conflicts as well as balance constraints, among other particularities. We present and compare constraint programming and integer programming approaches for solving this generalized problem. Summary of Contribution: The quadratic multiknapsack problem consists of packing a set of items of various weights into knapsacks of limited capacities -- with profits being associated with pairs of items packed into the same knapsack. This problem has been solved by various heuristics since its inception, and more recently it has also been solved with an exact method. We introduce a generalization of this problem which includes pairwise conflicts as well as balance constraints, among other particularities. We present and compare constraint programming and integer programming approaches for solving this generalized problem. The problem we address is clearly in the core of the operations research applications in which subsets have to be built and, in particular, we add the concept of fairness to the modeling and solution process by computationally evaluating techniques to take fairness into account. This is clearly at the core of computational evaluation of algorithms.

Islamic Values in Environmental Communication within the Malaysian Media: A Case Study of Utusan Malaysia and Berita Harian

2021 ◽  
Vol 37 (3) ◽  
pp. 54-72
Author(s):  
Mohamad Saifudin Mohamad Saleh ◽  
◽  
Shaidatul Akma Adi Kasuma ◽  
Mark Harris Zuknik ◽  
Nik Norma Nik Hasan ◽  
...  
Keyword(s):  
Content Analysis ◽  
Great Influence ◽  
Environmental Communication ◽  
Future Research ◽  
Great Understanding ◽  
The Core ◽  
Main Challenge ◽  
Unity Of God ◽  
Islamic Values

We argue that environmental communication within the Malaysian media landscape is influenced by Islamic beliefs and teachings. Although Islam has a great influence on environmental communication in Malaysia, it is an area underexplored by past studies. We conducted a content analysis on two mainstream Malay media outlets, namely Utusan Malaysia and Berita Harian, for a six-year period (2012-2017) in order to investigate the types of Islamic values which were represented in the environmental articles published by both newspapers. We also conducted interviews with 11 journalists from both newspapers to determine the purpose of using Islamic values in environmental articles. The result of content analysis discovered that tawhid (unity of God) is the most common Islamic value used in Utusan Malaysia’s environmental articles, while in Berita Harian, iman (faith) is the value which most commonly appears. In the interviews, journalists from Utusan Malaysia described that the value of tawhid is used the most in the environmental articles as it is one of the core values in Islam, while the journalists from Berita Harian explained that iman has been used the most as this value is an intrinsic part of the readers’ lives. However, most of the interviewees stated that the main challenge for them came from the need of the journalists themselves to have a great understanding of both Islam and environment. It is hoped that the findings of this study could serve as a reference for future research in the area of Islamic environmental communication. Keywords: Environmental communication, Islam, media, value, Malaysia.

Migrating Software Towards Mobile Technologies

2022 ◽  
pp. 1683-1700
Author(s):  
Liliana Maria Favre
Keyword(s):  
Mobile Technologies ◽  
Mobile Platforms ◽  
Business World ◽  
The Core ◽  
Mobile Software ◽  
Main Challenge ◽  
The World ◽  
Cross Platform ◽  
Platform Development ◽  
The Internet Of Things

New paradigms such as pervasive computing, cloud computing, and the internet of things (IoT) are impacting the business world. Smartphones are at the core of these paradigms by allowing us interaction with the world around us. In light of this, it is imperative to migrate a lot of existing non-mobile software to adapt it to the new technological reality. The main challenge to achieve this goal is the proliferation of mobile platforms. An integration of ADM (Architecture Driven Modernization), cross-platform development and formal metamodeling to face this kind of migration is described. The proposal was validated with the migration of object-oriented software to different mobile platforms through the multiplatform language Haxe. A comparison of the approach with traditional migration processes and the description of existing challenges in real projects of the scientific and industrial field are included.

Bilevel Integer Programs with Stochastic Right-Hand Sides

2021 ◽  
Author(s):  
Junlong Zhang ◽  
Osman Y. Özaltın
Keyword(s):  
Structural Properties ◽  
Large Scale ◽  
Value Function ◽  
Integer Program ◽  
Value Functions ◽  
Integer Programs ◽  
Solution Algorithms ◽  
Right Hand ◽  
Solution Methods ◽  
The Value Function

We develop an exact value function-based approach to solve a class of bilevel integer programs with stochastic right-hand sides. We first study structural properties and design two methods to efficiently construct the value function of a bilevel integer program. Most notably, we generalize the integer complementary slackness theorem to bilevel integer programs. We also show that the value function of a bilevel integer program can be characterized by its values on a set of so-called bilevel minimal vectors. We then solve the value function reformulation of the original bilevel integer program with stochastic right-hand sides using a branch-and-bound algorithm. We demonstrate the performance of our solution methods on a set of randomly generated instances. We also apply the proposed approach to a bilevel facility interdiction problem. Our computational experiments show that the proposed solution methods can efficiently optimize large-scale instances. The performance of our value function-based approach is relatively insensitive to the number of scenarios, but it is sensitive to the number of constraints with stochastic right-hand sides. Summary of Contribution: Bilevel integer programs arise in many different application areas of operations research including supply chain, energy, defense, and revenue management. This paper derives structural properties of the value functions of bilevel integer programs. Furthermore, it proposes exact solution algorithms for a class of bilevel integer programs with stochastic right-hand sides. These algorithms extend the applicability of bilevel integer programs to a larger set of decision-making problems under uncertainty.

HYBRID-FITNESS FUNCTION EVOLUTIONARY ALGORITHM BASED ON SIMPLEX CROSSOVER AND PSO MUTATION FOR CONSTRAINED OPTIMIZATION PROBLEMS

2009 ◽  
Vol 23 (01) ◽  
pp. 115-127 ◽  
Author(s):  
YIBO HU
Keyword(s):  
Constrained Optimization ◽  
Evolutionary Algorithm ◽  
Penalty Function ◽  
Feasible Solution ◽  
Optimization Problems ◽  
Fitness Function ◽  
Benchmark Problems ◽  
Crossover Operator ◽  
Hybrid Fitness ◽  
Constrained Optimization Problems

For constrained optimization problems, evolutionary algorithms often utilize a penalty function to deal with constraints, even if it is difficult to control the penalty parameters. To overcome this shortcoming, this paper presents a new penalty function which has no parameter and can effectively handle constraint first, after which a hybrid-fitness function integrating this penalty function into the objective function is designed. The new fitness function can properly evaluate not only feasible solution, but also infeasible one, and distinguish any feasible one from an infeasible one. Meanwhile, a new crossover operator based on simplex crossover operator and a new PSO mutation operator are also proposed, which can produce high quality offspring. Based on these, a new evolutionary algorithm for constrained optimization problems is proposed. The simulations are made on ten widely used benchmark problems, and the results indicate the proposed algorithm is effective.

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