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91.
92.
Modularity is an important concept in evolutionary theorizing but lack of a consistent definition renders study difficult. Using the generalized NK-model of fitness landscapes, we differentiate modularity from decomposability. Modular and decomposable systems are both composed of subsystems, but in the former, these subsystems are connected via interface standards, while in the latter, subsystems are completely isolated. We derive the optimal level of modularity, which minimizes the time required to globally optimize a system, both for the case of two-layered systems and for the general case of multi-layered hierarchical systems containing modules within modules. This derivation supports the hypothesis of modularity as a mechanism to increase the speed of evolution. Our formal definition clarifies the concept of modularity and provides a framework and an analytical baseline for further research.  相似文献   
93.
94.
There is a general sense of urgency that major technological transitions are required for sustainable development. Such transitions are best perceived as involving multiple transition steps along a transition path. Due to the path dependent and irreversible nature of innovation in complex technologies, an initial transition step along some preferred path may cut off paths that later may turn out to be more desirable. For these reasons, initial transition steps should allow for future flexibility, where we define flexibility as robustness regarding changing evidence and changing preferences. We propose a technology assessment methodology based on rugged fitness landscapes, which identifies the flexibility of initial transition steps in complex technologies. We illustrate our methodology by an empirical application to 2,646 possible future car systems.
Koen FrenkenEmail:
  相似文献   
95.
This paper argues that time-series econometrics provides valuable tools and opens exciting research opportunities to marketing researchers. It allows marketing researchers to advance traditional modeling and estimation approaches by incorporating dynamic processes to answer new important research questions. The authors discuss the challenges facing time-series modelers in marketing, provide an overview of recent methodological developments and several applications, and highlight fruitful areas for future research. This discussion is based on the First Annual Conference on Modeling Marketing Dynamics by Time Series Econometrics at the Tuck School of Business at Dartmouth, Hanover, New Hampshire, USA on September 16–17, 2004.Insights from the First Annual Conference, Tuck School of Business at DartmouthThis revised version was published online in May 2005 with a corrected cover date.  相似文献   
96.
It has long been argued that geographic co-location supports knowledge spillovers. More recently, this argument has been challenged by showing that knowledge spillovers mainly flow through social networks, which may or may not be localized at various geographic scales. We further scrutinize the conjecture of geographically bounded knowledge spillovers by focusing on knowledge flows between academia and industry. Looking into citations to non-patent literature (NPL) in 2385 Dutch polymer patents, we find that citation lags are shorter on average if Dutch rather than foreign NPLs are cited. However, when excluding individual and organizational self-citations, geographically proximate NPLs no longer diffuse faster than foreign NPLs. This suggests that knowledge is not ‘in the air’ but transferred by mobile individuals and/or direct university–industry collaboration. Our findings moreover suggest an important role of international conferences in the diffusion of recent scientific knowledge.  相似文献   
97.
In this paper we review evolutionary economic modelling in relation to environmental policy. We discuss three areas in which evolutionary economic models have a particularly high added value for environmental policy-making: the double externality problem, technological transitions and consumer demand. We explore the possibilities to apply evolutionary economic models in environmental policy assessment, including the opportunities for making policy-making endogenous to environmental innovation. We end with a critical discussion of the challenges that remain.  相似文献   
98.
We study whether bank efficiency is related to bank ownership in Russia. We find that foreign banks are more efficient than domestic private banks and, surprisingly, that domestic private banks are not more efficient than domestic public banks. These results are not driven by the choice of production process, the bank's environment, management's risk preferences, the bank's activity mix or size, the econometric approach, or the introduction of deposit insurance. The policy conclusion is that the efficiency of the Russian banking system may benefit more from increased levels of competition and greater access of foreign banks than from bank privatization.  相似文献   
99.
  总被引:1,自引:0,他引:1  
In this paper a methodology is proposed to compute spatial concentrations of point-based events on a network. The distance along the network is used as a measure of the spatial closeness of events. The network is divided into statistical units, based on a random distribution of points of measurement and corresponding network segments, which are the statistical units of reference. For each segment a dangerousness index is computed which indicates the distance-weighted number of traffic accidents in the neighbourhood. The statistical significance of clusters of accidents is tested using a Monte Carlo simulation. The methodology is applied to traffic accidents to detect dangerous locations on the road network of the city of Brussels in Belgium.  相似文献   
100.
    
In South Africa there has been a paucity of data on food and nutrition labelling since the publication of the new food‐labelling legislation. This study aimed to explore whether the nutrition information on food products influences consumer purchasing behaviour; reasons for reading or ignoring nutrition information on labels, and to investigate expectations regarding food / nutrition labelling. Nine focus‐group discussions were held with adult consumers (N=67) in Cape Town, South Africa. Food price was sometimes the only consideration when selecting food products, irrespective of quality and nutritional value. When buying products for the first time, consumers were more inclined to read the nutrition information compared to habitual purchases or buying known brands. The list of ingredients, nutrient content claims and specific health endorsement logos were considered important. Reasons for reading nutrition information were mainly to assess the nutritional value or health properties, to avoid certain ingredients/allergens and to determine quality. Consumers struggled to understand the information on labels, specifically the nutrition information table. A lack of time or interest, price concerns and trust in labelling information also emerged as reasons why consumers ignore the nutrition information. There is a need for simpler food labelling, more graphics, and less complex terminology, information overload and quantitative information. It is recommended that a standardised front‐of‐package labelling scheme and a single health endorsement logo for South Africa be considered. More should be done to educate consumers on utilising the information on food labels correctly, in order for them to make healthier food choices.  相似文献   
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