Network motifs in an inter-firm network

Firms build business relationships during economic activities. The goal of this paper is to clarify production mechanisms and economic functions by identifying characteristic patterns of inter-firm interactions. In this paper, we empirically analyze an inter-firm network consisting of about one million firms and four million directed links, in order to specify network motifs, which are small subgraphs that occur more frequently than expected in a randomly generated network. We found that V-shaped triads are network motifs, while feedforward and feedback loop are anti-motifs. By defining roles in the subgraph according to structural equivalence, we also detected the significance profile of roles characterizing the industry sector. The taxonomy of industries obtained from the profiles is economically meaningful. These empirical findings may serve to provide an easily interpretable view of the entire inter-firm network and to improve the efficiency and safety of economic systems.     

Application of optimal control in man power planning

Many techniques are met in the literature (see for instance Bartholomew and Forbes (Statistical Techniques for Manpower Planning. wiley, New York 1979); Gunz (Organiz. Stud. 9(4), 529–554, 1988); Becker and Huselid (Human Resour. Manage. 38, 287–301, 1999); Wagner et al. (J. Manage. Med. 14(5/6), 383–405, 2000); Harris and Ogbonna (J. Business Res. 51, 157–166, 2001); Rogg et al. (J. Manage. 27, 431–449, 2001), among others), for planning the manpower resources. However, we haven’t seen in the literature an empirical study regarding the proper application of optimal control, which considered to be the most efficient method for multi-objective programming. With this in mind, we analyse in this paper the way of applying optimal control for manpower planning. For this purpose, and in order to facilitate the presentation, we first adopted a comparatively simple dynamic system (plant), with analytical presentation of stocks and flows. Next we proceed to the formulation of an optimal control problem, aiming to achieve in the most satisfactory way some preassigned targets. These targets mainly refer to a desirable trajectory of the plant stocks over time, in order to fully satisfy the needs for human resources over the planning horizon. Finally we present a method of solution of the formulated control problem which is based on the use of the generalized inverse Lazaridis (Qual. Quan. 120, 297–306, 1986). We believe that it is very important for successful management, that the policy makers have to know the effect of their polices and to determine the optimal path of the state variables (i.e. the ones describing the system) before the realization of the plan, so as to be able to reform their strategies, reallocate the resources and arrange the infrastructure accordingly, if all these are necessary, as it can be depicted from the optimal control solution.     

Applying fuzzy quality function deployment to identify service management requirements for customer quality needs

In this paper a fuzzy quality function deployment to identify service management requirements for customer quality needs is developed. First, customer quality needs with importance degree have been investigated followed by development of service management requirements for satisfying the observed customer quality needs. Furthermore, construct a fuzzy relation matrix to link service management requirements and customer quality needs based on cross-functional expertise. The aggregated fuzzy assessments of various service management requirements are ranked to determine their importance priority. Finally, an empirical study for identifying the service management requirements for customer quality is used to demonstrate the proposed approach.     

Academic content,research productivity,and tenure

This study examines the influence of a Finance doctoral program’s academic content on the research productivity of the graduates at the time of the tenure decision. The results of this investigation show that a Finance program’s academic content has no influence on the total number of publications of program graduates, but finds a significant relationship between academic content and graduate’s records of publications in top finance journals by the time of the tenure evaluation. More precisely, doctoral programs requiring more mathematically oriented classes such as Continuous Time Finance and/or Stochastic Calculus produce graduates who have a better record of publication in top finance journals at the time of tenure than those graduating from programs without these requirements.     

Estimation of parameters of parallelism model with elliptically distributed errors

In this paper we consider some improved estimators of the intercept and slope parameters in a parallelism model with errors belonging to a sub-class of elliptically contoured distributions. We derive the exact bias, MSE matrices and quadratic risk expressions for these estimators. It is shown that the dominance properties of these estimators are the same as under normal theory. Further, it is shown that the shrinkage factor of the Stein estimators is robust with respect to the regression parameters and unknown mixing distributions.     

Generalization practices in qualitative research: a mixed methods case study

The purpose of this mixed methods case study was to examine the generalization practices in qualitative research published in a reputable qualitative journal. In order to accomplish this, all qualitative research articles published in Qualitative Report since its inception in 1990 (n =  273) were examined. A quantitative analysis of the all 125 empirical qualitative research articles revealed that a significant proportion (i.e., 29.6%) of studies involved generalizations beyond the underlying sample that were made inappropriately by the author(s). A qualitative analysis identified the types of over-generalizations that occurred, which included making general recommendations for future practice and providing general policy implications based only on a few cases. Thus, a significant proportion of articles published in Qualitative Report lack what we call interpretive consistency.     

Using ad hoc measures for response styles: a cautionary note

This research note addresses the challenge of how to optimally measure acquiescence response style (ARS) and extreme response style (ERS). This is of crucial importance in assessing results from studies that have tried to identify antecedents of response styles (such as age, education level, national culture). Using survey data from the Netherlands, a comparison is made between the traditional method and a more recently proposed method of measuring ARS and ERS (i.e., the convergent validity across both methods is assessed). The traditional method is based on an ad hoc set of related items. The alternative method uses a set of randomly sampled items to optimize heterogeneity and representativeness of the items. It is found that the traditional method may lead to response style measures that are suboptimal for estimating levels of ARS and ERS as well as relations of ARS and ERS with other variables (like hypothesized antecedents). Recommendations on how to measure response styles are provided.     

Interpreting the results of studies using latent variable models to assess data quality: an empirical example using confirmatory factor analysis

Latent variable models (LVMs) offer one route to examine the quality of data collected in surveys. The possibility exists that individuals equivalent in their true level of a construct or variable being measured are unlikely to have equivalent observed responses as a function of an extraneous variable, e.g., group membership. This potential is labeled here as differential item functioning (DIF). Survey methods generally considers measurement bias to be estimators that do no not accurately reflect true values. DIF may be thought of as differential measurement bias, i.e., measurement bias conditional on group membership. As a function of group membership, the degree, amount, or type of measurement bias changes. DIF has the potential to negatively affect the quality of data. LVMs, e.g., confirmatory factor analysis (CFA), offer one tool to assess DIF. However, few published examples exist in the survey research field and training in the interpretation of these models is lacking. The purpose of the current paper is to describe CFA sufficiently for interpretive purposes and demonstrate an empirical application of CFA to assess survey data quality to provide further interpretive guidance. References are provided for analysts wishing to conduct analyses of this type.     

Estimation of trade and domestic distortions: an application to world agriculture

The world’s nations often produce commodities for which they have no apparent comparative advantage, and do so with techniques that are not particularly efficient by world standards. These inefficiencies may arise from various forms of trade and domestic distortions, as described in Chau et al., Int Econ Rev 44:1079–1095, (2003). We estimate these distortions for 33 countries of the world using a newly compiled data set. We find that domestic distortions tend to be slightly more important than trade distortions. For the average country, revenues in the agricultural sector would be 26% higher if domestic distortions were eliminated, but 21% higher if trade distortions were eliminated. Our measures of trade and domestic distortions across countries provide a complement to measures of protectionism such as producer subsidy equivalents.