FPT-algorithms for some problems related to integer programming

This paper studies a new version of the location problem called the mixed center location problem. Let P be a set of n points in the plane. We first consider the mixed 2-center problem, where one of the centers must be in P, and we solve it in \(O(n^2\log n)\) time. Second, we consider the mixed k-center problem, where m of the centers are in P, and we solve it in \(O(n^{m+O(\sqrt{k-m})})\) time. Motivated by two practical constraints, we propose two variations of the problem. Third, we present a 2-approximation algorithm and three heuristics solving the mixed k-center problem (\(k>2\)).     

The matching extension problem in general graphs is co-NP-complete

A simple connected graph G with 2n vertices is said to be k-extendable for an integer k with \(0<k<n\) if G contains a perfect matching and every matching of cardinality k in G is a subset of some perfect matching. Lakhal and Litzler (Inf Process Lett 65(1):11–16, 1998) discovered a polynomial algorithm that decides whether a bipartite graph is k-extendable. For general graphs, however, it has been an open problem whether there exists a polynomial algorithm. The new result presented in this paper is that the extendability problem is co-NP-complete.     

Reliability evaluation of a multicast over coded packet networks

Network coding is a generalization of conventional routing methods that allows a network node to code information flows before forwarding them. While it has been theoretically proved that network coding can achieve maximum network throughput, theoretical results usually do not consider the stochastic nature in information processing and transmission, especially when the capacity of each arc becomes stochastic due to failure, attacks, or maintenance. Hence, the reliability measurement of network coding becomes an important issue to evaluate the performance of the network under various system settings. In this paper, we present analytical expressions to measure the reliability of multicast communications in coded networks, where network coding is most promising. We define the probability that a multicast rate can be transmitted through a coded packet network under a total transmission cost constraint as the reliability metric. To do this, we first introduce an exact mathematical formulation to construct multicast connections over coded packet networks under a limited transmission cost. We then propose an algorithm based on minimal paths to calculate the reliability measurement of multicast connections and analyze the complexity of the algorithm. Our results show that the reliability of multicast routing with network coding improved significantly compared to the case of multicast routing without network coding.     

What innovation managers really do: a multiple-case investigation into the informal role profiles of innovation managers

Over the last fifteen years companies tended to formalise their innovation management activities and to establish formal jobs like the innovation officer, the network manager or the innovation manager. Knowledge of the informal role profiles of these formal roles is still rare. HR and R&D Managers do not know which informal role profile might suit them best, thus having difficulties to assign the best candidates for jobs in innovation management. Researchers cannot help to resolve the problem. Our research answers the question what innovation managers really do, by analysing their tasks, skills and traits, theoretically based on informal role theories. Furthermore, we will analyse how these characteristics change with company size. To provide answers to our research questions we choose a multiple-case study approach. We found, among others, that innovation managers fulfil the role of the relationship and process promotor or a combination of both with the champion, but we also found, that the innovation manager’s roles profile becomes fuzzier with shrinking company size. Our results have practical implications for top management and also HR and R&D managers, enabling them to better select and steer employees in innovation management. Researchers will be able to build on our results because we offer a comprehensive understanding of the informal role profiles of innovation managers based on informal role theories.     

Empathic emotion and leadership performance: An empirical analysis across 38 countries

The purpose of our research is to examine the relationship between subordinate ratings of a target-leader's empathic emotion and boss ratings of performance of that target-leader. Furthermore, using hierarchical linear modeling, we assess whether the cultural background of the target-leader moderates this relationship. Our results show that leaders who are rated by their subordinates as engaging in behaviors that signal empathic emotion are perceived as better performers by their bosses. In addition, we found that the GLOBE societal culture dimension of power distance was a significant cross-level moderator of the relationship between empathic emotion and performance. Implications for leading in cross-cultural and multicultural contexts are discussed.     

A two-study investigation of item wording effects on leader–follower convergence in descriptions of the leader–member exchange (LMX) relationship

The leader–member exchange (LMX) theory of leadership focuses on the quality of relationships built between leaders and subordinates; LMX measures are designed to assess the quality of these relationships. Since the leader and subordinate are jointly embedded in the relationship, it is reasonable to assume that their ratings of their relationship will converge to some reasonable extent. However, leader–member convergence on the most widely used measures, the LMX-7 and SLMX-7 scales, has historically been low. To address this, we conduct two studies to investigate whether item wording and content might be a cause of poor LMX convergence. The obtained results support the conclusion that the wording and content of these measures are, in fact, introducing attributional and social desirability biases into the rating process and causing some of the poor LMX convergence that is commonly seen. Implications for extant and future LMX research are discussed.     

The role of character in ethical leadership research

The study of character is a legitimate and essential topic for the analysis of leadership in organizations. We undertake three key objectives in this article to stimulate meaningful dialogue. First, a brief historical overview of the extant body of literature on character is provided. Second, working definitions of character and character-based leadership are introduced. Third, new directions for organizational scholars interested in examining the role of character-based leadership in both their research and teaching domains are suggested.     

Reporting quality data on your hospital website: what? why? how?

Explore the challenges in making performance improvement data publicly available on hospital websites, and consider some practical tips and suggestions for aligning organizational goals with community and consumer needs.