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Ohne Zusammenfassung     

ARTIFICIAL NEURAL NETWORKS: A NEW APPROACH TO MODELING INTERREGIONAL TELECOMMUNICATION FLOWS*

ABSTRACT. During the last thirty years there has been much research effort in regional science devoted to modeling interactions over geographic space. Theoretical approaches for studying these phenomena have been modified considerably. This paper suggests a new modeling approach, based upon a general nested sigmoid neural network model. Its feasibility is illustrated in the context of modeling interregional telecommunication traffic in Austria, and its performance is evaluated in comparison with the classical regression approach of the gravity type. The application of this neural network approach may be viewed as a three-stage process. The first stage refers to the identification of an appropriate network from the family of two-layered feedforward networks with 3 input nodes, one layer of (sigmoidal) intermediate nodes and one (sigmoidal) output node (logistic activation function). There is no general procedure to address this problem. We solved this issue experimentally. The input-output dimensions have been chosen in order to make the comparison with the gravity model as close as possible. The second stage involves the estimation of the network parameters of the selected neural network model. This is performed via the adaptive setting of the network parameters (training, estimation) by means of the application of a least mean squared error goal and the error back propagating technique, a recursive learning procedure using a gradient search to minimize the error goal. Particular emphasis is laid on the sensitivity of the network performance to the choice of the initial network parameters, as well as on the problem of overfitting. The final stage of applying the neural network approach refers to the testing of the interregional teletraffic flows predicted. Prediction quality is analyzed by means of two performance measures, average relative variance and the coefficient of determination, as well as by the use of residual analysis. The analysis shows that the neural network model approach outperforms the classical regression approach to modeling telecommunication traffic in Austria.     

The Geography of Knowledge Spillovers Between High-Technology Firms in Europe: Evidence from a Spatial Interaction Modeling Perspective

The focus in this article is on knowledge spillovers between high-technology firms in Europe, as captured by patent citations. The European coverage is given by patent applications at the European Patent Office that are assigned to high-technology firms located in the EU-25 member states (except Cyprus and Malta), the two accession countries Bulgaria and Romania, and Norway and Switzerland. By following the paper trail left by citations between these high-technology patents we adopt a Poisson spatial interaction modeling perspective to identify and measure spatial separation effects to interregional knowledge spillovers. In doing so we control for technological proximity between the regions, as geographical distance could be just proxying for technological proximity. The study produces prima facie evidence that geography matters. First, geographical distance has a significant impact on knowledge spillovers, and this effect is substantial. Second, national border effects are important and dominate geographical distance effects. Knowledge flows within European countries more easily than across. Not only geography, but also technological proximity matters. Interregional knowledge flows are industry specific and occur most often between regions located close to each other in technological space.     

Analytical characterization of lacquer objects excavated from a Chu tomb in China

This work presents the results of an investigation of the lacquer objects excavated from a Chu tomb in China (Warring States, 481–221 BC). This study is engaged in the examination of the methods and the materials used for the urushi coating on the objects. X-Ray fluorescence and Scanning Electron Microscopy/Energy Dispersive Using X-Ray (SEM/EDX) analyses were applied for the pigment identification. The results show that vermilion was for the red colour, while carbon black was for the black colour. Pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) was applied for the characterization of the lacquer resulting that it is based on urushi. The possibility to classify the drying oil (tung or linseed oil) present in the lacquer is highlighted and discussed in this paper. Py-GC/MS with in-situ hydrolysis and methylation reagent tetramethylammonium hydroxide (TMAH) were performed on reference materials of linseed oil and tung oil as well as on the lacquer object samples. The results show that it is possible to unambiguously identify the drying oil, in our case, linseed oil was identified to retard the rate of hardening.     

Scientific investigation of the paint and adhesive materials used in the Western Han dynasty polychromy terracotta army,Qingzhou, China

A royal tomb of early period of the Western Han dynasty (206 B.C–8 A.D) was excavated by archaeologists in Qingzhou County, Shandong Province in 2006. Over 2000 polychromy terracotta soldiers, horses, chariots, servants etc. were unearthed from the tomb. All the terracotta figures are one quarter or one sixth as large as the livings, most of them were painted with well designed patterns. In order to gain complete information about the materials and techniques used for the polychromy on the terracotta army, five samples from the painted areas were taken. In addition, one sample from the area to adhere one leg to the ploychromy horse body was also obtained. The analytical techniques applied include XRF, FTIR, Py-GC/MS and GC/MS. Chinese purple, cinnabar, lead red and ochre were used as pigments, while animal glue was identified as binding medium and adhesive in the polychromy terracotta army in the Han Dynasty. The results definitely will provide new evidence about the materials and technologies used in Han Dynasty. Especially, the binding medium identified is different in comparison with Qin Shihuang's terracotta army (259–210 BC).     

山东青州香山西汉墓彩绘陶俑胶接材料研究

本文利用x射线荧光、红外光谱、热裂解气相色谱质谱（Vy-GC-MS）和气相色谱质谱（GC-MS）,对山东青州香山西汉墓出土彩绘陶俑紫色、红色和褐色彩绘层中使用的胶接材料,以及取自马腿与马身粘接处的胶接物进行了分析。分析结果显示彩绘颜料以及马腿粘接物中的有机物均为动物胶。此研究结果为同一时期此类陶质彩绘文物的胶接材料研究提供了很好的借鉴。