External Spillovers Research Articles

DOB-based piezoelectric vibration control for stiffened plate considering accelerometer measurement noise

This paper presents a composite control strategy for the active suppression of vibration due to the unknown disturbances, such as external excitation, harmonic effects and control spillover, as well as high-frequency accelerometer measurement noise in the all-clamped stiffened plate. The proposed composite control action based on the modal approach, consists of two contributions including feedback part and feedforward part. The feedback part is the well-known PID controller, which is widely used to increase the structure damping and improve its dynamic performance close to the resonance frequencies. In order to get better performance for vibration suppression, the weight matrixes is optimized by chaos sequence. Then an improved disturbance observer (IDOB) as the feedforward compensation part is developed to enhance the vibration suppression performance of PID under various disturbances and uncertainties. The proposed IDOB can simultaneously estimate the various disturbances dynamically as well as measurement noise acting on the system and suppress them by feedforward compensation design. A rigorous analysis is also given to show why the IDOB can effectively suppress the unknown disturbances and measurement noise. In order to verify the proposed composite control algorithm (IDOB-PID), the dSPACE real-time simulation platform is used and an experimental platform for the all-clamped stiffened plate active vibration control system is set up. The experimental results demonstrate the effectiveness, practicality and strong anti-disturbances ability of the proposed control strategy.

When Distance Disappears: Inventors, Education, and the Locus of Knowledge Spillovers

Abstract This paper discusses the role of education in shaping the geographical breadth of knowledge spillovers. Data pertaining to 6,051 European inventions reveal that inventors with a high level of education, such as a university or doctoral degree, rely more on external spillovers regardless of the geographical location of their sources. Controlling for this effect, they also access geographically wider knowledge spillovers. This result holds after controlling for alternative explanations, such as the inventors' network and the site where the research is performed. By contributing to individual openness, education thus provides a means to break through geographical barriers to attain knowledge diffusion.

External Influences on Business Cycle Synchronization in the Euro Area

Most studies of business cycle synchronization in the EMU identify a core set of counties with high synchronization and a periphery set of countries with low synchronization. Using a structural VAR with model uncertainty, we identify spillover effects from shocks that originate in the United States, the EMU, and the rest of the world to test whether external influences can explain the existence of the core and periphery. Most countries typically found in the core respond to external spillovers in similar ways, leading to more synchronized business cycles. The response to external influences in the countries traditionally found in the periphery, on the other hand, help explain their exclusion from the core.

Joint ventures in patent contests with spillovers and the role of strategic budgeting

Abstract We consider an R&D contest between n firms in the presence of external spillovers. Our analysis focuses on the effects of these spillovers on joint venture activities between firms. In particular, we are interested in how different budget responsibilities within the research joint venture (RJV) affect profits of firms taking part in the joint venture and profits of their non-cooperating rival firms. Three arrangements for RJVs are analyzed: First, cooperation, in which the firms participating in the joint venture completely share the research they create in the innovation process and each firm has a sovereign budget responsibility. Second, a collusive arrangement in which the participating firms not only share their research but have joint budget responsibilities in the sense that they make all strategic choices cooperatively and maximize joint profits. Third, a hierarchical form, in which the cooperating firms establish joint headquarters which have strategic budget responsibility in the sense that it can strategically subsidize R&D efforts of its member firms so as to maximize overall RJV profits. We show that the first two arrangements can be mimiced in the hierarchical structure and that a hierarchical structure is optimal if it completely subsidizes its members’ R&D activities. In this case all rival firms are driven out of the contest.

From West to East: Estimating External Spillovers to Australia and New Zealand

This paper examines the size and source of external spillovers to Australia and New Zealand based on a structural vector autoregression (VAR) approach. It finds that during the last decade shocks from emerging Asia have become more important than those from the United States in affecting Australia’s business cycle. A 1 percent shock to emerging Asia’s growth is found to shift Australian growth by about 1/3 percent. Furthermore, there is evidence that commodity prices dominate the transmission of shocks from emerging Asia to Australia. The influence of emerging Asia on New Zealand is found to come indirectly through Australia, with Australian shocks transmitting almost one-on-one to New Zealand, largely through financial factors.

From West to East: Estimating External Spillovers to Australia and New Zealand

This paper examines the size and source of external spillovers to Australia and New Zealand based on a structural vector autoregression (VAR) approach. It finds that during the last decade shocks from emerging Asia have become more important than those from the United States in affecting Australia’s business cycle. A 1 percent shock to emerging Asia’s growth is found to shift Australian growth by about 1/3 percent. Furthermore, there is evidence that commodity prices dominate the transmission of shocks from emerging Asia to Australia. The influence of emerging Asia on New Zealand is found to come indirectly through Australia, with Australian shocks transmitting almost one-on-one to New Zealand, largely through financial factors.

Foreign direct investment and R&D-offshoring

We analyze a two-country model of Foreign Direct Investment (FDI). Two firms, each of which is originally situated in only one of the two countries, first decide whether to build a plant in the foreign country. Then, they decide whether to relocate R&D activities. Finally, they engage in product-market competition. Our main points are: first, FDI liberalization causes a relocation of R&D activities if intrafirm communication is sufficiently well developed, external spillovers are substantial, competition is not too strong and foreign markets are not too small. Second, such a relocation of R&D activities will usually nevertheless increase domestic welfare since it only occurs if intrafirm communication is well developed and therefore knowledge generated and obtained abroad flows back to the domestic country. Third, the potential of R&D offshoring makes FDI itself more likely. Fourth, when countries are asymmetric, the small-country firm is more likely to offshore its R&D activities into the large country than conversely.

Nonlinear GARCH Models and Volatility Spillover

We extend the class of GARCH models to comprise asymmetric and nonlinear effects on volatility. In particular, we do not only explain future volatility of a time series on its own past, but allow for external influences and spillovers between capital markets. For this generalized class of models, the asymptotic behavior of the Quasi-Maximum-Likelihood estimator of model parameters is derived. The models are applied to time series of fx-rates. It is found that in particular the simple asymmetric models lead to improved performance.

Are Supply and Plant Inspections Complements or Substitutes? A Strategic and Operational Assessment of Inspection Practices in Biotechnology

This paper theoretically and empirically examines the conventional wisdom in procurement management that often portrays supply inspections and supplier plant inspections as substitutes. We develop a theoretical model that focuses on potential internal spillover costs of the buyer receiving low-quality inputs and external spillover costs should low-quality inputs go undetected. Key to our analysis is the condition of whether a buyer can commit to the intensity of supply inspection. If a buyer cannot commit, supply inspections and plant inspections are substitutes, as widely believed. The two types of inspections, however, may become complements when a buyer is able to commit to the intensity of supply inspection. Complementarity is especially likely when (a) external spillovers are smaller than expected internal spillovers, which depends on the level of buffer inventory, (b) when knowledge sharing between buyer and supplier becomes more effective as the supplier allocates more resources to learning for quality improvement, or (c) when hiding aspects of the production processes is easier for suppliers. We empirically evaluate our model with a new data set drawn from a large biotechnology manufacturer. Empirical results provide broad support for theory, which, we argue, might help to explain variation in inspection practices across industries. Our theory and empirical analysis contribute to the literatures on strategic management, organizational economics, and procurement management by highlighting the organizational and strategic use of inspection practices.

Gaining the competitive edge using internal and external spillovers: a dynamic analysis

This paper studies the evolution of two clusters of firms competing on a common market. Firms exit and enter a cluster based on the perceived chances for profits inside and outside the cluster. Information about profits are diffused by direct communication between firms. Internal and external spillover effects reduce the overall costs of firms in the clusters depending on the number of firms in the own and the competing cluster. A discrete time deterministic dynamical system describing the evolution of cluster sizes is derived. An analysis of the long run attractors of the system and their basins of attraction is used to compare the effects of advantages of a cluster with respect to the size of internal and external spillover effects, respectively. Furthermore, the implications of slow and fast exit and entry behavior of firms for the long run survival and the size of the clusters are studied.

An examination of return and volatility patterns on the Irish equity market

This study examines the pattern of returns and volatility on Irish equity markets, over a period when the markets were deregulated. GARCH and GARCH-IN-MEAN models are applied to data from three study periods. Volatility spillovers from the London stock market are considered, providing a test for evidence of a change in the degree of this influence. Within sample results show that GARCH models do provide a useful description of Irish equity returns. Furthermore, the inclusion of external volatility improves the model fit. There is no evidence that deregulation coincides with an alteration in the impact of external volatility. Forecast results indicate some evidence that the inclusion of external volatility spillovers does improve the forecast accuracy of GARCH models. Tests indicate that a GARCH-IN-MEAN specification does not suit Irish equity data.

External spillovers, internal spillovers and the geography of production and innovation

We consider a three-location duopoly model such that (i) firms choose production and innovation locations before (Bertrand) competition takes place and (ii) there are internal and external knowledge spillovers. We show: (1) agglomerations where firms earn negative profits may exist when there are both external and internal knowledge spillovers; (2) greater external spillovers do not necessarily favor agglomeration; (3) decreasing communication costs tend to favor agglomeration; (4) there are exactly two types of agglomeration equilibria: either both firms innovate in the agglomeration, or there is an innovator and an imitator; and (5) if there is a location where both firms produce, then innovation must take place in this location.

International Technological Spillovers and Economic Growth. The Italian Case

This study moves along the recent research path started by Coe and Helpman (1995) which aims at unraveling the mechanics of spillovers in the economic growth of nations. Unlike many previous studies, which are mainly cross-sectional, our analysis focuses on the experience of Italy. The time-series analysis 1963-1995 shows that the Italian economic growth has been critically influenced by external technology funneled by imports of investment goods. Moreover, empirical evidence suggests that Italian growth has been and still is more related to external rather than internal spillovers; moreover, the extent of external spillovers has shown some relevant changes throughout the years: aggregate (but not industrial) spillovers have slowed down since the eighties.