Common Breaks in Means for Cross‐Correlated Fixed‐T Panel Data

This note considers a panel data model in which the variable of interest has undergone a common structural break in the mean. The object of interest is the unknown breakpoint. The challenge is to device an estimator that is consistent when the data are cross‐correlated and the number of time periods T is fixed and cannot be increased without bound. The proposed solution involves taking an already existing estimator initially proposed for cross‐section uncorrelated panels and applying it to defactored data. Consistency is established as the number of cross‐section units N grows large, and is verified in small samples using Monte Carlo simulation.     

Precipitation Kinetics During Post-heat Treatment of an Additively Manufactured Ferritic Stainless Steel

Metallurgical and Materials Transactions A - The microstructure response of laser-powder bed fusion (L-PBF)-processed ferritic stainless steel (AISI 441) during post-heat treatments is studied in...     

Network subsystem design

It is argued that the bandwidth of the CPU/memory data path on workstations will remain within the same order of magnitude as the network bandwidth delivered to the workstation. This makes it essential that the number of times network data traverses the CPU/memory data path be minimized. Evidence which suggests that the cache cannot be expected to significantly reduce the number of data movements over this path is reviewed. Hardware and software techniques for avoiding the CPU/memory bottleneck are discussed. It is concluded that naively applying these techniques is not sufficient for achieving good application-to-application throughput; they must also be carefully integrated. Various techniques that can be integrated to provide a high bandwidth data path between I/O devices and application programs are outlined     

Path-Based Error Coverage Prediction

We present an analytical technique that uses fault injection data for estimating the coverage of concurrent error detection mechanisms in microprocessors. A major problem in such estimations is that the coverage depends on the program executed by the microprocessor as well as the input sequence to the program. We propose a method that predicts the error coverage for a specified input sequence based on fault injection data obtained for another input sequence. Our results show that post-injection analysis is a promising approach for reducing the cost of coverage estimation.     

ADAS at work: assessing professional bus drivers’ experience and acceptance of a narrow navigation system

Cognition, Technology & Work - Due to the argued benefits of passenger comfort, cost savings, and road safety, the bus sector is showing increasing interest in advanced driver-assistance...     

Defuzzification of spatial fuzzy sets by feature distance minimization

We present a novel defuzzification method, i.e., a mapping from the set of fuzzy sets to the set of crisp sets, and we suggest its application to image processing. Spatial fuzzy sets are, e.g., useful as information preserving representations of objects in images. Defuzzification of such a spatial fuzzy set can be seen as a crisp segmentation procedure. With the aim to provide preservation of selected quantitative features of the fuzzy set, we define the defuzzification of a fuzzy set to be a crisp set which is as close as possible to the fuzzy set, where the distance measure on the set of fuzzy sets, that we propose for defuzzification, incorporates selected local and global features of the fuzzy sets. The distance measure is based on the Minkowski distance between feature representations of the sets. The distance minimization, performed in the suggested defuzzification method, provides preservation of the selected quantitative features of the fuzzy set. The method utilizes the information contained in the fuzzy representation for defining a mapping from the set of fuzzy sets to the set of crisp sets. If the fuzzy set is a representation of an unknown crisp original set, such that the selected features of the original set are preserved in the fuzzy representation, then the defuzzified set may be seen as an approximate reconstruction of the crisp original. We present four optimization algorithms, exhibiting different properties, for finding the crisp set closest to a given discrete fuzzy set. A number of examples, using both synthetic and real images, illustrate the main properties of the proposed method. An evaluation of both theoretical aspects of the method, and its results, is given.     

Sediment depth attenuation of biogenic phosphorus compounds measured by 31P NMR

Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, 31P NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible.