A new approach to modelling sigmoidal curves

Growth and diffusion phenomena have become of great interest to investigators in many disciplines, such as Biology, Demography, Economy, Agriculture, etc. These processes are generally analyzed by means of growth curves. As, in nature, it is not possible for any variable to continue growing indefinitely, we can consider any growth process to have an upper limit or saturation level. Thus, should a model represent a growth phenomenon, it will be described by a sigmoidal or S-shaped curve. There are a wide variety of growth models in general and specific literature. Of these, the logistic model is without doubt one of the most studied in practice, as well as some modifications of it, including recent investigations directed to the decomposition of a growth curve into various logistic components [Technol. Forecast. Soc. Change 47 (1994) 89; Technol. Forecast. Soc. Change 61 (1999) 247.]. In all the cases above, the adopted approach includes fitting the trend curve to the data by means of a well-known estimation procedure, such as least squares. We suggest a somewhat different approach, which consists of expressing the model through its differential equation and searching for a functional specification for the variable representing growth rate. Two series have been chosen from the recent literature in order to illustrate the methodology presented.     

互联网与业务流程融合的创新扩散及关键因素研究

依据创新扩散理论与流程观,提出一种企业互联网融合（互联网与业务流程融合）测度模型,包括信息化管理影响因素和相关假设,并将互联网与价值链上业务流程融合规模作为互联网融合的度量标准。基于196家传统企业调查数据,采用Logistic模型和结构方程建模对样本数据进行对比分析,验证所提出的模型及假设,揭示企业实施互联网技术支持业务活动的状况,鉴别企业之间互联网融合差异的关键解释因素,同时提出一种研究企业实施互联网技术支持业务活动的新途径。     

成渝经济圈R & D空间溢出网络结构研究

利用修正空间引力模型和社会网络分析法,对成渝经济圈R&D空间溢出网络结构进行探索。研究发现,成渝经济圈R&D分布的地缘邻近性显著,南北贯线的地缘邻近性明显强于东西贯线的空间相似性;区域R&D空间溢出的网络结构具有“主核-多中心”特点,“强链”和 “弱链”区域分异明显;区域内R&D空间溢出的出度和入度两极分化严重,区域间R&D空间溢出不完全服从区域经济发展水平势差所带来的方向性;整体来看,区域内R&D空间溢出四大凝聚子群基本契合区域经济整合的边界分异。     

Should environmental R&D be prioritized?

An innovator may not be able to capture the full social benefit of her innovation and, therefore, governments support private R&D through various measures. We compare a market good innovation—to develop a more efficient technology to produce a standard market good—with an environmental innovation—to develop a more efficient abatement technology—that has the same potential to increase the social surplus. In the first-best outcome, which can be achieved by offering an R&D subsidy and a diffusion subsidy, the R&D subsidy should be greatest for an environmental innovation, whereas the diffusion subsidy should be greatest for a market good innovation. The ranking of the two types of subsidies reflects that the appropriability problem is greater for an environmental innovation than for a market good innovation.     

Organizational innovation: The challenge of measuring non-technical innovation in large-scale surveys

Although the implementation of innovative organizational concepts is considered to be highly important for a company's competitiveness, so far there has been little research on possible approaches to measure and monitor organizational innovations in large-scale surveys. Based on an item-oriented typology of organizational innovations which serves as the precondition for a common understanding, we describe and compare how organizational innovations have been measured through existing surveys in Europe. Using a large-scale survey comprising data of 1450 German manufacturing companies, we show how these different approaches lead to significantly different results regarding the organizational innovativeness of companies within one and the same sample. We derive four implications for the future measurement and monitoring of organizational innovations. Our findings contribute to the further development of an adequate methodology for an organizational innovation monitoring system.     

基于扩散指数模型的房地产市场景气循环研究——以北京市为例

基于扩散指数模型构建房地产市场景气循环指标体系,采用北京市住宅市场与经济基本面的历史数据,计算不同时期北京市房地产市场的扩散指数,绘制北京市房地产市场的景气循环曲线,并根据景气循环曲线与历史数据对北京市未来房地产市场的景气情况进行预测。最后,提出在上述市场预测情况下的市场调控策略。     

A dynamic diffusion model for managing customer's expectation and satisfaction

The paper aims at answering the generic question on how suppliers make the suitable and well-timed decisions in diffusing new technology effectively to adopters. Three major attempts are made for the study: First, investigating the entire process of the adoption and diffusion of technology innovation with reasonably well-accepted models in each areas. Second, proposing an integrated model by concatenating in structured manner the three prominent models for the management of technology innovation such as diffusion model, adoption model, and customer satisfaction model. Third, exploring the dynamic mechanism underlying outward behaviors of the integrated model proposed in the study which depicts the causal relationships that influence technology adoption and diffusion behaviors. An exploration of the dynamic mechanism underlying outward behaviors of the integrated model is presented in the study by introducing the system dynamics simulation technique. These attempts made for the study and the results perhaps allow both researchers and practitioners to gain insight into the causal factors influencing customers' adoption decision making processes and thereby into the potential diffusion patterns resulting from those adoption processes.     

产业共性技术扩散三阶段模型构建与仿真研究

结合产业共性技术相关理论与技术扩散模型，以政府作用为调节变量，构建产业共性技术扩散的三阶段仿真模型，对产业共性技术扩散三阶段演化特征进行探讨，借助Matlab平台对主体采纳行为和共性技术扩散速度进行仿真，并以我国新能源汽车产业共性技术扩散为例对仿真结果进行实证检验。研究结果表明：产业共性技术扩散先后经历了权威决策、二次创新以及附随扩散3个阶段;产业共性技术扩散的企业采纳比例遵循“S”型曲线规律，而产业共性技术扩散速度出现了“上升-下降-再上升”的“N”型走势;直接采纳二次研发成果的企业，对产业共性技术扩散影响较大;政府在整个产业共性技术扩散过程中发挥关键作用，但在扩散不同阶段政府介入方式与程度会有所差异;二次创新投入比例与成功率影响产业共性技术扩散规模和速度;只有将产业共性技术转化成专有技术或新产品，才能实现共性技术有效扩散。     

A technology replacement model with variable market potential — An empirical study of CRT and LCD TV

The rapidly changing economic environment and increasingly fierce competition indicate that companies must innovate in both their products and marketing strategies if they are to continue to flourish. Specifically, the ability to accurately predict the demand for products is crucial when firms decide to allocate their resources, especially in the fast moving high technology industries, where there is very high investment in R&D and production facilities. This study establishes a forecast model for technology replacement based on the diffusion model with population growth used for the variable market potential. The proposed model is then applied to investigate the CRT and LCD TV market.The results suggest that the new model is more accurate than the constant market potential model in fitting and forecasting performance. Consumers who purchase a TV for the first time are likely more attracted to LCD TV rather than CRT TV. As for those individuals who already own a CRT TV, the attraction is not strong enough to encourage them to replace their current CRT TV with a new LCD TV. Moreover, it is noted that the falling price of LCD TV is an essential factor in encouraging purchases.     

Role of network structure and network effects in diffusion of innovations

Why does diffusion of innovation sometimes propagate throughout the whole population, and why at other times does it halt in its interim process? The current paper provides a potential answer to this question by developing a simple computational model of social networks. The proposed computational approach incorporating small-world graphs enables the authors to find that diffusion of innovation is more likely to fail in a random network than in a highly clustered network of consumers. A marketing implication is that the choice of initial target groups and their network structures matter in influencing whether an innovation makes full or partial penetration, in markets where network effects plays a role.