Solving binary programming problems using homotopy theory ideas

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lilia Alanís-López ◽  
Martha-Selene Casas-Ramírez ◽  
José-Fernando Camacho-Vallejo

PurposeThe aim of the study is to show that merging two areas of mathematics – topology and discrete optimization – could result in a viable option to solve classical or specialized integer problems.Design/methodology/approachIn the paper, discrete topology concepts are applied to propose a metaheuristic algorithm that is capable to solve binary programming problems. Particularly, some of the homotopy for paths principles are used to explore the solution space associated with four well-known NP-hard problems herein considered as follows: knapsack, set covering, bi-level single plant location with order and one-max.FindingsComputational experimentation confirms that the proposed algorithm performs in an effective manner, and it is able to efficiently solve the sets of instances used for the benchmark. Moreover, the performance of the proposed algorithm is compared with a standard genetic algorithm (GA), a scatter search (SS) method and a memetic algorithm (MA). Acceptable results are obtained for all four implemented metaheuristics, but the path homotopy algorithm stands out.Originality/valueA novel metaheuristic is proposed for the first time. It uses topology concepts to design an algorithmic framework to solve binary programming problems in an effective and efficient manner.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bertrand Géradin

Purpose Luxembourg is the jurisdiction of choice for many private equity and venture capital investors/funds. Though the optimum balance of financing instruments in relation to any structure varies according to its particular circumstances, one factor that all Luxembourg domiciled FDI structures have in common is the requirement for an appropriate level of equity investment. This article intends to summarize some of the topics frequently encountered in relation to equity structuring choices. Design/methodology/approach Author details the different steps and choices available to investors and funds. The article offers answers to questions to provide a broad, yet detailed, overview of the process and journey; from selecting the vehicle right through to distributing to investors, governance, and compliance. Findings To avoid an expensive mistake, it is paramount that the private equity or venture capital investors and management team receive detailed advice to ensure: (i) the deal is structured in the most tax efficient manner possible and the commercial deal is suitable for all parties, and (ii) the deal is structured in a manner which is effective under Luxembourg law, for both tax and legal purposes. Practical implications It is important that non-Luxembourg lawyers are able to identify key issues when negotiating the terms of the investment documents, in particular, the articles of association and shareholders' agreement. Originality/value Practical guidance from Luxembourg lawyer specializing in corporate law, mergers and acquisitions, venture capital and private equity transactions.


2014 ◽  
Vol 42 (6) ◽  
pp. 482-499 ◽  
Author(s):  
Erik Sandberg

Purpose – For many retailers organic growth through the opening of new stores is a crucial cornerstone of the business model. The purpose of this paper is to explore the store opening process conducted by retail companies. The research questions cover: first, the role and organisation of the establishment function in charge of the process; second, the activities and functions involved in the process; and third, the coordination mechanisms applied during the process. Design/methodology/approach – This research considers the store opening process as a company-wide project, managed by an establishment function, in which internal functions as well as external suppliers need to be coordinated. A multiple case study of eight retail companies is presented, focusing on the organisation of the establishment function, a mapping of the store opening process and the application of coordination mechanisms. Findings – The role and organisation of the establishment function is described and the store opening process is summarised into 11 main activities to be conducted by either the establishment function or other involved functions. During the store opening process six different coordination mechanisms are utilised, including mutual adjustments and direct supervision, as well as different types of standardisation. Originality/value – This research seeks to improve our understanding for the store opening process and how it can be managed and controlled in an effective manner.


2018 ◽  
Vol 35 (7) ◽  
pp. 1459-1476 ◽  
Author(s):  
Dilbagh Panchal ◽  
Sachin Kumar Mangla ◽  
Mohit Tyagi ◽  
Mangey Ram

Purpose The purpose of this paper is to develop a fuzzy methodology approaches based framework for carrying the risk analysis of a real industrial system of a urea fertilizer industry located in northern part of India. Design/methodology/approach Petri Net approach was applied for representing the series-parallel arrangement of the considered system. Various failure causes related to different subsystems or equipment of the considered system were listed under FMEA approach and their Risk Priority Number was tabulated. Further, to overcome the drawbacks of traditional FMEA approach in risk ranking fuzzy FMEA and grey relation analysis (GRA) approaches were applied within traditional FMEA approach and the ranking results were compared for better and effective decision making of risky components. Findings The proposed framework has overcome the drawbacks of tradition FMEA approach in an effective and efficient manner. Causes AC7, CL3, ST2, DR3 and NR3 of centrifugal compressor, hot heat exchanger, ammonia convertor reactor, cold condenser and ammonia separator have been identified as the most critical failure causes of the considered system. Originality/value The proposed framework has been tested with its application on an ammonia synthesis system of the considered process industry. The risk ranking results would be highly useful in developing a planned maintenance policy for the considered system which further results in improving the system availability.


2018 ◽  
Vol 35 (9) ◽  
pp. 2052-2079 ◽  
Author(s):  
Umamaheswari E. ◽  
Ganesan S. ◽  
Abirami M. ◽  
Subramanian S.

Purpose Finding the optimal maintenance schedules is the primitive aim of preventive maintenance scheduling (PMS) problem dealing with the objectives of reliability, risk and cost. Most of the earlier works in the literature have focused on PMS with the objectives of leveling reserves/risk/cost independently. Nevertheless, very few publications in the current literature tackle the multi-objective PMS model with simultaneous optimization of reliability, and economic perspectives. Since, the PMS problem is highly nonlinear and complex in nature, an appropriate optimization technique is necessary to solve the problem in hand. The paper aims to discuss these issues. Design/methodology/approach The complexity of the PMS problem in power systems necessitates a simple and robust optimization tool. This paper employs the modern meta-heuristic algorithm, namely, Ant Lion Optimizer (ALO) to obtain the optimal maintenance schedules for the PMS problem. In order to extract best compromise solution in the multi-objective solution space (reliability, risk and cost), a fuzzy decision-making mechanism is incorporated with ALO (FDMALO) for solving PMS. Findings As a first attempt, the best feasible maintenance schedules are obtained for PMS problem using FDMALO in the multi-objective solution space. The statistical measures are computed for the test systems which are compared with various meta-heuristic algorithms. The applicability of the algorithm for PMS problem is validated through statistical t-test. The statistical comparison and the t-test results reveal the superiority of ALO in achieving improved solution quality. The numerical and statistical results are encouraging and indicate the viability of the proposed ALO technique. Originality/value As a maiden attempt, FDMALO is used to solve the multi-objective PMS problem. This paper fills the gap in the literature by solving the PMS problem in the multi-objective framework, with the improved quality of the statistical indices.


Kybernetes ◽  
2018 ◽  
Vol 47 (10) ◽  
pp. 1956-1972 ◽  
Author(s):  
Archana Shrivastava

Purpose This research study uses authentic leadership (AL) model for leadership development. The purpose of this paper is to focus on the developmental perspective where the attention is on the processes. As the authenticity involves both owing one’s personal experiences and acting in accordance with one’s true self, the emphasis is on self-awareness and self-regulation. The influence of the person’s personal history and trigger events are considered as significant antecedents for generating AL. As the research was facilitated by the participation and collaboration of the number of individuals with the researcher for common purpose, i.e. developing AL, action research methodology is adopted. Design/methodology/approach The methodology used was based on the self-assessment exercises in the controlled environment. The programme used intensive counselling sessions, Neuro Linguistics programming (NLP), career autobiographies, mind maps, workshops and storytelling sessions as tools. Certified counsellors and trainers were out-sourced for conducting such sessions. With the information generated through various sources, detailed career autobiographies of students’ self-image were generated. These reports were then critically analysed on “Nvivo”, a software that supports qualitative and mixed research methods. Comprehensive data analysis was done to pull the information together and make sense of it. The development process model of AL began with how individuals interpret their accumulated life experiences with the “Who I am?” approach. NLP was used as a research instrument which involved question-based discussions, value elicitation exercise and “Anchoring and Mentor table”. The results that came after the exercises were reported by the students in a one-page autobiography. Findings The students learnt to live by their inner compass. They were finally able to relate themselves and their identity with their beliefs, thereby, understanding the term, “Who Am I”; the intentions closely related with the components of AL. Students realized that each one of them was unique. What lied beneath were exposed and the students were more at ease once they realized that they were able to balance these emotions and use them towards behaving congruently. The research concluded that doing such kind of exercises along with the main stream subjects is definitely going to help students emerge as a better person, employee and an authentic leader in the future. Practical implications The approach helped students become self-aware and self-confident and therefore enhanced their capacity to adapt positively to social set ups personally and professionally. The results suggest that such leadership development programmes along with the main stream subjects can foster AL giving students new abilities and embodied skills to deal with the practical challenges of life in a more effective manner. Originality/value This research study supports new emerging strategy of educating managers to become effective leaders and demonstrate that the development of AL can be fostered by such interventions during their journey of becoming leaders. Further, researches on whether AL can be developed through planned interventions can be certified through longitudinal studies in this area.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bowen Yi ◽  
Da Shi ◽  
Fangfang Shi ◽  
Liang Zhang

Purpose By building on cooperation–competition theory, this study aims to investigate the multidimensional flipped effects of neighborhood hotels on Airbnb listings’ popularity, examining the degree to which such impacts are influenced by hotel types and geographical areas. Design/methodology/approach This study explores the interdependent and competitive relationship between neighborhood hotels and Airbnb from the perspective of effects on Airbnb listings’ popularity by exploring a data set covering 10,492 Airbnb listings and 2,691 hotels from Ctrip. Findings Results reveal that neighborhood hotels’ number of reviews, review ratings and prices each have positive spillover effects on Airbnb listings’ popularity, while quality assurance labels and negative review topic sentiments exert competitive effects on Airbnb popularity. Moreover, the number of budget chain hotels and high-star hotels have positive and negative effects on Airbnb popularity, respectively. Geographical areas also have a moderating effect on the relationship between various hotel-related influencing factors and Airbnb. Practical implications This study can offer hotel managers and Airbnb operators a clearer understanding of these businesses’ coexisting relationship. Findings can also provide Airbnb-specific guidelines for practitioners in terms of site selection, promotional features and development strategies for Airbnb listings. Originality/value This study establishes a cooperation–competition relationship model between hotels and Airbnb and considers the flipped effects of hotels on Airbnb for the first time. It expands previous studies by considering the multidimensional effects of hotels on Airbnb listings’ popularity and by examining the influences of hotel types and geographical areas on hotels’ impacts on Airbnb.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mehdi Barati ◽  
Hadiseh Fariditavana

PurposeThe purpose of this study is to first assess how the US healthcare financing system is influenced by income variation. Then, it examines whether or not the impact of income variation is asymmetric.Design/methodology/approachFor the analyses of this paper, the autoregressive distributed lag (ARDL) model is implemented to a data set covering the period from 1960 to 2018.FindingsThe results provide evidence that major funding sources of aggregate healthcare expenditure (HCE) respond differently to changes in income. The results also imply that the effect of income is not always symmetric.Originality/valueMany studies have attempted to identify the relationship between income and HCE. A common feature of past studies is that they have only focused on aggregate HCE, while one might be interested in knowing how major funders of aggregate HCE would be affected by changes in income. Another common feature of past studies is that they have assumed that the relationship between income and HCE is symmetric.


2020 ◽  
Vol 20 (1) ◽  
pp. 123-142 ◽  
Author(s):  
Nicolas Chevrollier ◽  
Jianhong Zhang ◽  
Thijs van Leeuwen ◽  
André Nijhof

Purpose Despite the scholarly attention for the integration of sustainability within business strategy and processes, little is known about how strategic orientations of companies influence this integration. Drawing on stewardship theory, this paper aims to analyse the influence of strategic orientation of companies on their environmental, social and corporate governance (ESG) performance and the moderating effect of three different political models of economy (Rhine, British and American). Design/methodology/approach This paper creates a measurement for strategic orientations by using a coding scheme with a five-category evaluation matrix. The main empirical analysis is done by a fixed-effect model with a panel data set covering 179 publicly traded companies over the 2009-2016 period. Findings The conclusions of this paper present that – consistent over time – a stronger orientation on stewardship positively associates with higher ESG performance. Additionally, the political model of economy significantly alters the relationship indicating the effect of strategic orientation on ESG performance. The relationship is significantly stronger in the Rhine model and significantly weaker in the British model, when both compared to the American model. Originality/value The implications of this paper are vital to understanding corporate strategic orientation and its relationship to actual corporate behaviour and long-term performance. Implementing the elements of focus, motivation, commitment, support and communication linked to a stewardship orientation is fundamental to achieve higher levels of sustainability performance.


2020 ◽  
Vol 24 (2) ◽  
pp. 324-345 ◽  
Author(s):  
Yan Lin ◽  
Chenxi Wang

Purpose This paper aims to explore the effect of participant composition and contribution behavior of the different types of participants on the quality of knowledge generation in online communities. Design/methodology/approach This study samples all the featured articles in Chinese Wikipedia and performs a Cox regression to reveal how participant composition and contribution behavior affect the quality of articles in different contexts. Findings The results show that an increase in the number of participants increases the possibility of either enhancing or reducing the article quality. In most cases, the greater the proportion of core members (people who frequently participate in editing), the higher the possibility of enhancing the article quality. Occasional participants’ editorial behavior hinders quality promotion, this negative effect weakens when such editorial behavior becomes more frequent. Practical implications The findings help to better leverage the role of online communities in practice and to achieve knowledge collaboration in a more efficient manner. For example, an appropriate centralized organizational form should be established in online communities to improve the efficiency of crowd contributions. And it is worth developing mechanism to encourage participants to frequently participate in editing the article. Originality/value This study contributes to the research on the organizational forms of online communities by showing the effect of participant composition and behavior in the new form of organizing on knowledge generation. This study also contributes to the research on wisdom of crowds by revealing who in a group of participants, in what context, and by what means influence knowledge generation.


2019 ◽  
Vol 40 (2) ◽  
pp. 361-375 ◽  
Author(s):  
Nan Zhang ◽  
Zhenyu Liu ◽  
Chan Qiu ◽  
Weifei Hu ◽  
Jianrong Tan

Purpose Assembly sequence planning (ASP) plays a vital role in assembly process because it directly influences the feasibility, cost and time of the assembly process. The purpose of this study is to solve ASP problem more efficiently than current algorithms. Design/methodology/approach A novel assembly subsets prediction method based on precedence graph is proposed to solve the ASP problem. The proposed method adopts the idea of local to whole and integrates a simplified firework algorithm. First, assembly subsets are generated as initial fireworks. Then, each firework explodes to several sparks with higher-level assembly subsets and new fireworks are selected for next generation according to selection strategy. Finally, iterating the algorithm until complete and feasible solutions are generated. Findings The proposed method performs better in comparison with state-of-the-art algorithms because of the balance of exploration (fireworks) and exploitation (sparks). The size of initial fireworks population determines the diversity of the solution, so assembly subsets prediction method based on precedence graph (ASPM-PG) can explore the solution space. The size of sparks controls the exploitation ability of ASPM-PG; with more sparks, the direction of a specific firework can be adequately exploited. Practical implications The proposed method is with simple structure and high efficiency. It is anticipated that using the proposed method can effectively improve the efficiency of ASP and reduce computing cost for industrial applications. Originality/value The proposed method finds the optimal sequence in the construction process of assembly sequence rather than adjusting order of a complete assembly sequence in traditional methods. Moreover, a simplified firework algorithm with new operators is introduced. Two basic size parameters are also analyzed to explain the proposed method.


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