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PurposeBlockchain technology is provoking significant disruptions, thereby affecting supply chain management. This study endeavoured to advance research regarding blockchain-based supply chain traceability by identifying the opportunities and limitations that accompany the adoption of public blockchains. Therefore, the purpose of the study is to contribute to contemporary supply chain research by an assessment of blockchain technology and its linkages to traceability.Design/methodology/approachThis paper is conceptual. The authors summarised the relevant literature on the concepts of supply chain traceability, conceptualised key elements exclusive to the public blockchain and highlighted opportunities and limitations in implementing traceability using blockchains.FindingsIncompatibilities were identified between general traceability and the public blockchain. However, when embracing the blockchain's privacy model, the blockchains can support information exchange in supply chains where vulnerability towards third parties, the confidentiality of information, or the privacy of participants are concerns. Furthermore, the public blockchain can support areas of supply chains where institutional interest is lacking.Originality/valueThis is one of the first papers in an international supply chain management journal to critically analyse the intersection of specific blockchain characteristics and supply chain traceability requirements. The authors thereby add to the discussion of designs for a disintermediated, peer-to-peer models and guide researchers and practitioners alike in exploring the application of disruptive change from blockchain technologies. By setting focus on the privacy model, the paper identifies the potential application and future research approaches to exploit the elementary strength of the blockchain.

In recent years, floating lidar systems (FLS) have been used in increasing numbers for project planning and design of offshore wind farm projects. To assess the quality of the measured data or the wind resources, an exact knowledge of the measurement uncertainty of the FLS is important. However, this is difficult because there is usually no reference measurement system at the offshore sites where FLSs are to be used to assess wind resources. In order to estimate the quality of the measurements or the measurement uncertainty for a site without a reference measurement system, in this case only measurement uncertainties from measurement campaigns or trial campaigns that have already been carried out can be used. However, the respective wind and wave conditions differ from location to location. In this respect, a direct transfer of the measurement uncertainty from one measurement location to another location is again subject to a certain uncertainty. In this paper, we explore the possibilities of a different, simulation-based, approach. First, we discuss which parts of the measurement uncertainty of the FLS can be investigated in the context of simulations. Additionally, we present a workflow for the simulation of an FLS for different wind and wave conditions and an approach to determine and compare the simulated bin-averaged deviations for these conditions with real measurement data. Finally, we show a comparison of the simulated uncertainties with measurement uncertainties determined during a six-month measurement campaign of an FLS against an offshore measurement mast and a fixed reference lidar and give an outlook on possible further use cases of this simulation-based methodology.

Floating lidar system (FLS) measurements are essential for offshore site assessment. Here an important part is the data accuracy and uncertainty, which are determined by the wind speed deviations between the FLS and reference data obtained during a verification trial. The reference anemometer is normally a cup anemometer installed on a met mast. Due to the different measurement principles, mast wake effects, the distance between FLS and reference, and FLS motions, the share of these factors in the deviations are not clear. In this work, we present an FLS verification measurement conducted in proximity to the FINO3 met mast located in the North Sea in 2017. Additionally, the data acquired by a fixed, non-moving lidar installed on FINO3 is considered. This allows studying wind speed deviations with different, well-defined influence factors. Methods for analyzing the wind speed accuracy and uncertainty, which are used in FLS verification and classification, are presented and applied to all combinations of data sources. As a preliminary work, directional wind speed deviations are studied to define a valid wind direction sector used for filtering for all data sources. As a result, the wind speed deviations between the FLS and the references are dominated by the FLS motion and the distance to the reference, respectively. Nevertheless, uncertainties may also be seen for the fixed lidar. For the classification results, approximately 1/3 of the sensitivity is contributed by the different measurement principles.

This work validates a numerical model of the Fraunhofer IWES LiDAR-Buoy by using open sea measurements. Such floating LiDAR systems (FLS) have been deployed for almost twenty years, aiming at exploring the offshore wind resource with lower cost. However, the uncertainty of wind measurements from a moving LiDAR are not clear, particularly due to the wave- and current-induced motion of the buoy. Therefore a numerical model with state-of-the-art approaches in conventional oil and gas industry was developed to quantify uncertainty and understand the effect of environmental conditions on the buoy. The model was validated against data from a measurement campaign at the offshore research platform FINO 3. The results show the challenges and limitations when transferring the experience from the oil and gas industry directly because of the different geometries and the much smaller buoys used for FLS. It has been found that the position of the LiDAR is dominated by the current, which is however commonly simplified in the state-of-the-art approach; the rotational motions are significantly influenced by the wave and can be reproduced up to a certain limit.

PurposeBetween 1997 and 2005, the German government provided owner‐occupied subsidies to fund new private housing construction and stock purchases to increase owner‐occupied housing. The purpose of this paper is to analyse the impact of these subsidies on total housing construction for the 1997‐2007 period using regionalised data. This paper tests for differences between counties and cities and examines whether local participation in housing programs is related to regional migration and fertility. Based on the dynamic results, short‐ and long‐run elasticities with respect to the subsidy program are calculated.Design/methodology/approachA balanced panel data set is used that covers approximately 95 percent of all German NUTS‐3 regions (counties and independent cities) for the 1997‐2007 period. To control for serial correlation, possible endogenous relationships and omitted variable bias problems, the System Generalised Methods of Moments estimation technique is applied.FindingsA significantly positive impact of subsidised construction is detected in counties with an elasticity of approximately 0.2 in the short run and 0.48‐0.58 in the long run. The elasticities in independent cities are significantly lower, at 0.11 and 0.32‐0.37, respectively. No significant effect of migration on construction was found, in contrast to a significantly positive effect of fertility, especially at the county level. The estimates suggest a significantly negative effect of subsidised stock purchases on total construction.Research limitations/implicationsTests for other countries using regional data on interest rates, construction costs and housing prices could lead to further insights.Practical implicationsThe findings suggest that further owner‐occupied subsidy programs should be geared toward families or larger households. It also seems important to provide sufficient building land to enable households to make use of housing construction subsidies.Originality/valueThis is the first regional paper to examine housing construction elasticities with respect to a subsidisation program for housing construction and stock purchases that was designed for virtually all households in a country. It is also the first paper to test for differences in participation in a large‐scale, national housing program related to migration and fertility.

We apply the stock flow model for the German residential rental market using a data set that includes the overwhelming majority of nomenclature of territorial units for statistics (NUTS) 3 regions for the 2004-2007 period. Aside from proving conditional rental price convergence, we have detected a turnaround in vacancy stocks between the short and the long term. While East German counties and West German independent cities currently exhibit the highest and lowest vacancy rates, respectively, the opposite holds true at equilibrium. Leaning on theoretical suggestions, landlords in well-developed areas have incentives to hold onto vacancies in view of future rent increases. Our results support this idea, which demonstrates the significantly positive impact of household income and net birth rate on the natural vacancy rate.

We analyze landlord market heterogeneity in the German rental housing market. Using data from the German Social‐Economic Panel survey for the years 2000–2005, we firstly identify significant differences in implicit prices for housing attributes between private, public, and association landlords in a cross‐section analysis through comprehensive segmentation testing. Based on that, we secondly present a balanced panel analysis for the entire period to investigate market price heterogeneity over time. In general, we detect the length of residence and the building size as the most important determinants for landlord segmentation. Most notably, differences between private and non‐private landlords are identified.

We apply the stock flow model for the German residential rental market using a data set that includes the overwhelming majority of nomenclature of territorial units for statistics (NUTS) 3 regions for the 2004-2007 period. Aside from proving conditional rental price convergence, we have detected a turnaround in vacancy stocks between the short and the long term. While East German counties and West German independent cities currently exhibit the highest and lowest vacancy rates, respectively, the opposite holds true at equilibrium. Leaning on theoretical suggestions, landlords in well-developed areas have incentives to hold onto vacancies in view of future rent increases. Our results support this idea, which demonstrates the significantly positive impact of household income and net birth rate on the natural vacancy rate.

Assessing the uncertainty of floating lidar systems for different wind and wave climates is a difficult task. One possible solution to close this gap is a validated simulation environment for floating lidar systems. An approach for such a simulation environment is being developed within the German research project MALIBU and will be presented. This paper gives an overview about the simulation model which is being developed and shows ideas and first results regarding the validation aspects for the moving lidar environment. Furthermore an outlook for further steps regarding the validation of the complete simulation model for a floating lidar system (FLS) is being given.

This paper sheds new light on the assessment of firm networks via multiple directorships in terms of corporate firm performance. Using a large sample of European listed firms in the period from 2003 to 2011 and system GMM we find a significant compensation effect on corporate firm performance for the initial negative effect of horizontal multiple directorships by product market competition. In markets with effective competition, horizontal multiple directorships turn out to be an efficient mechanism to increase firm performance and thus assure competitive advantages. By contrast, linkages between up- and downstream firms have no significant influence on financial performance, irrespective of the level of competition intensity.

We combine the real estate model of Potepan (1996) with the spatial equilibrium approach of Roback (1982) to prove the interdependency of housing prices, rental prices, building land prices and income via one simultaneous equilibrium analysis. Using unique cross-sectional data on the majority of German counties and cities for 2005, we estimate the equations in their structural and reduced form. The results show significantly positive interaction effects of income and real estate prices. Moreover, we can confirm model predictions concerning the majority of exogenous determinants. In particular, expectations about population development seem to be among the most important determinants of price and income disparities between regions in the long term.

This paper departs from a preliminary near-shore measurement test campaign hold at El Pont del Petroli (PdP), Barcelona (Spain) where measurements from a Doppler wind-lidar buoy (the ”floating” lidar) are cross-examined against an on-shore reference lidar. From this framework the methodological analysis to intercompare two such lidars in terms of the retrieved Horizontal Wind Speed (HWS) - as key variable - is presented along with an overview of the signal-processing block diagram. Central to this work is to introduce the main error indicators (e.g., bias, RMSE, determination coefficient, absolute error and scatter plots) used to assess the performance of the floating lidar in the campaign. Finally, it is shown that even a basic smoothing procedure on the retrieved 1-s HWS time series is enough to enhance the determination coefficient against the reference lidar Turbulence Intensity (TI).