Cut generation for an employee timetabling problem

Motivated by an industrial application, we study a specific employee timetabling problem. Several investigations are being conducted: a lower bound by Lagrangian relaxation, a heuristic based on a cut generation process and an exact method by Benders decomposition. Experimental results on real and generated instances are reported

Réductions de domaine lagrangiennes pour le problème de minimisation des pénalités d'avance et de retard ponderées sur une machine

Cet article présente de nouvelles règles d\u27élimination pour le problème de minimisation des pénalités d\u27avance et de retard sur une machine, avec ousans dates de disponibilité. Ces règles, basées sur une décomposition lagrangienne, permettent de réduire considérablement les fenêtres d\u27exécution des tâches, et, ainsi, d\u27utiliser efficacement d\u27autres règles d\u27élimination classiques. Les expérimentations montrent que des instances comportant jusqu\u27à 70 tâches sans date de disponiblité, et 40 tâches avec dates de disponibilité, peuvent être résolues optimalement en une heure, en intégrant ces propriétés dans un branch-and-bound

The role of the exit in the initial screening of investment opportunities: The case of business angel syndicate gatekeepers

The exit process has been largely ignored in business angel research.. The practitioner community identifies the difficulty in achieving exits as the most pressing problem for investors. This has been attributed to the failure of investors to adopt an exit-centric approach to investing. The validity of this claim is examined via a study of the investment approach of 21 ‘gatekeepers’ (managers) of angel groups in Scotland and Northern Ireland. Most gatekeepers say that they do consider the exit when they invest. However, this is contradicted by a verbal protocol analysis which indicates that the exit is not a significant consideration in their initial screening process. The small number of exits achieved by the groups is consistent with the general lack of an exit-centric approach to investing. Only three groups exhibit evidence of a strong exit-centric approach to investing. The lack of exits may have a negative impact on the level of future angel investment activity

Does family involvement in management reduce the risk of business failure? The moderating role of entrepreneurial orientation

This study explores the question of whether—and under which circumstances—family involvement helps avoid business failure. We hypothesize that it is family involvement in management, rather than ownership, which reduces the risk of failure during economic downturns; however, this effect is negatively affected by the firm’s entrepreneurial orientation (EO). We argue that EO hinders reaching consensuses on and commitment to family-centered goals, which are focused on long-term survival. We analyze 369 manufacturing firms in Spain from 2007 to 2013, and find that family involvement in management reduces the risk of business failure, but this effect decreases as EO increases

Entrepreneurs' exit and paths to retirement : theoretical and empirical considerations

The number of ageing entrepreneurs in micro- and small-sized companies is rapidly increasing in Finland and other European Union countries. Over half a million jobs, in over one hundred thousand companies within the EU, are lost annually due to unsuccessful, predominantly retirement-related transfers of businesses. This challenge coincides with EU Grand Challenges and has been highlighted in the Entrepreneurship 2020 Action Plan (European Commission 2013). It has been estimated that in Finland, some 8000 jobs are lost yearly due to the ageing of entrepreneurs. Therefore, entrepreneur ageing has implications not only for the ageing individual but also for the company and the society at large. As entrepreneurs age it becomes more essential for them to start planning when and how they transition into retirement. While they may experience several exits and subsequent re-entries into working life via buying or starting new companies, exiting ones entrepreneurial career due to old age retirement differs from exits that occur earlier during the career. In this chapter, we provide a short overview of the entrepreneur retirement and exit literature from an age perspective. Furthermore, we present a theoretical conceptualization which combines entrepreneur retirement process with exit theories. This will enable scholars to better understand the retirement process, including decision-making, transitioning, and adjustment to retirement. We also provide empirical evidence using data collected among Finnish entrepreneurs in 2012 and 2015, where we outline the types of exits and assess several factors, including age, in association with exit intentions.fi=vertaisarvioitu|en=peerReviewed

Does Family Involvement in Management Reduce the Risk of Business Failure? The Moderating Role of Entrepreneurial Orientation

This study explores the question of whether - and under which circumstances - family involvement helps avoid business failure. We hypothesize that it is family involvement in management, rather than ownership, which reduces the risk of failure during economic downturns; however, this effect is negatively affected by the firm's entrepreneurial orientation (EO). We argue that EO hinders reaching consensuses on and commitment to family-centered goals, which are focused on long-term survival. We analyze 369 manufacturing firms in Spain from 2007 to 2013, and find that family involvement in management reduces the risk of business failure, but this effect decreases as EO increases.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This study has been partially supported by financial aid from the Spanish Ministry of Economy and Competitiveness (Projects ECO2012-36160, ECO2014-58799-R and ECO2015-67296-R) and from the Project S2015/HUM-3417 (cofinanced by the Communtiy of Madrid and European Social Fund)

Business angel exits: A theory of planned behaviour perspective

Although there are a handful of studies on business angel investment returns, the business angel literature has given little or no attention to exits and the exit strategy. This is surprising given that a primary objective of investing is to achieve a capital gain through some form of liquidity event. Using the theory of planned behaviour (TPB) as an interpretative heuristic, we examine how exits happen: specifically, what are the motivations to seek an exit and to what extent are they planned or opportunistic? Based on multiple case studies in which business angels were invited to tell the story of their most recent exit(s), the evidence suggests that the majority of liquidity events are the outcome of planned behaviour. We propose a typology of angel-backed investment exits as the basis for identifying future directions for research and developing practical advice to angels on effective business practices

The impact of digital start-up founders’ higher education on reaching equity investment milestones

This paper builds on human capital theory to assess the importance of formal education among graduate entrepreneurs. Using a sample of 4.953 digital start-ups the paper evaluates the impact of start-up founding teams’ higher education on the probability of securing equity investment and subsequent exit for investors. The main findings are: (1), teams with a founder that has a technical education are less likely to remain self-financed and are more likely to secure equity investment and to exit, but the impact of technical education declines with higher level degrees, (2) teams with a founder that has doctoral level business education are less likely to remain self-financed and have a higher probability of securing equity investment, while undergraduate and postgraduate business education have no significant effect, and (3) teams with a founder that has an undergraduate general education (arts and humanities) are less likely to remain self-financed and are more likely to secure equity investment and exit while postgraduate and doctoral general education have no significant effect on securing equity investment and exit. The findings enhance our understanding of factors that influence digital start-ups achieving equity milestones by showing the heterogeneous influence of different types of higher education, and therefore human capital, on new ventures achieving equity milestones. The results suggest that researchers and policy-makers should extend their consideration of universities entrepreneurial activity to include the development of human capital