The Economic Impact of Social Ties: Evidence from German Reunification

We use the fall of the Berlin Wall in 1989 to show that personal relationships which individuals maintain for non-economic reasons can be an important determinant of regional economic growth. We show that West German households who have social ties to East Germany in 1989 experience a persistent rise in their personal incomes after the fall of the Berlin Wall. Moreover, the presence of these households significantly affects economic performance at the regional level: it increases the returns to entrepreneurial activity, the share of households who become entrepreneurs, and the likelihood that firms based within a given West German region invest in East Germany. As a result, West German regions which (for idiosyncratic reasons) have a high concentration of households with social ties to the East exhibit substantially higher growth in income per capita in the early 1990s. A one standard deviation rise in the share of households with social ties to East Germany in 1989 is associated with a 4.6 percentage point rise in income per capita over six years. We interpret our findings as evidence of a causal link between social ties and regional economic development.economic development, German reuni cation, networks, social ties

Social Structure and Development: A Legacy of the Holocaust in Russia

We document a statistical association between the severity of the persecution and mass murder of Jews (the Holocaust) by the Nazis during World War II and long-run economic and political outcomes within Russia. Cities that experienced the Holocaust most intensely have grown less, and cities as well as administrative districts (oblasts) where the Holocaust had the largest impact have worse economic and political outcomes since the collapse of the Soviet Union. Although we cannot rule out the possibility that these statistical relationships are caused by other factors, the overall patterns appear generally robust. We provide evidence on one possible mechanism that we hypothesize may link the Holocaust to the present---the change it induced in the social structure, in particular the size of the middle class, across different regions of Russia. Before World War II, Russian Jews were predominantly in white collar (middle class) occupations and the Holocaust appears to have had a large negative effect on the size of the middle class after the war.

Physical layer authenticated image encryption for Iot network based on biometric chaotic signature for MPFrFT OFDM system

In this paper, a new physical layer authenticated encryption (PLAE) scheme based on the multi-parameter fractional Fourier transform–Orthogonal frequency division multiplexing (MP-FrFT-OFDM) is suggested for secure image transmission over the IoT network. In addition, a new robust multi-cascaded chaotic modular fractional sine map (MCC-MF sine map) is designed and analyzed. Also, a new dynamic chaotic biometric signature (DCBS) generator based on combining the biometric signature and the proposed MCC-MF sine map random chaotic sequence output is also designed. The final output of the proposed DCBS generator is used as a dynamic secret key for the MPFrFT OFDM system in which the encryption process is applied in the frequency domain. The proposed DCBS secret key generator generates a very large key space of (Formula presented.). The proposed DCBS secret keys generator can achieve the confidentiality and authentication properties. Statistical analysis, differential analysis and a key sensitivity test are performed to estimate the security strengths of the proposed DCBS-MP-FrFT-OFDM cryptosystem over the IoT network. The experimental results show that the proposed DCBS-MP-FrFT-OFDM cryptosystem is robust against common signal processing attacks and provides a high security level for image encryption application. © 2023 by the authors

Authenticated public key elliptic curve based on deep convolutional neural network for cybersecurity image encryption application

The demand for cybersecurity is growing to safeguard information flow and enhance data privacy. This essay suggests a novel authenticated public key elliptic curve based on a deep convolutional neural network (APK-EC-DCNN) for cybersecurity image encryption application. The public key elliptic curve discrete logarithmic problem (EC-DLP) is used for elliptic curve Diffie–Hellman key exchange (EC-DHKE) in order to generate a shared session key, which is used as the chaotic system’s beginning conditions and control parameters. In addition, the authenticity and confidentiality can be archived based on ECC to share the (Formula presented.) parameters between two parties by using the EC-DHKE algorithm. Moreover, the 3D Quantum Chaotic Logistic Map (3D QCLM) has an extremely chaotic behavior of the bifurcation diagram and high Lyapunov exponent, which can be used in high-level security. In addition, in order to achieve the authentication property, the secure hash function uses the output sequence of the DCNN and the output sequence of the 3D QCLM in the proposed authenticated expansion diffusion matrix (AEDM). Finally, partial frequency domain encryption (PFDE) technique is achieved by using the discrete wavelet transform in order to satisfy the robustness and fast encryption process. Simulation results and security analysis demonstrate that the proposed encryption algorithm achieved the performance of the state-of-the-art techniques in terms of quality, security, and robustness against noise- and signal-processing attacks

Experimental Simulation for Load Reduction Techniques on Underground Utilities using Geofoam

This paper investigates an experimental study on reducing stress acting on buried flexible pipes by using expanded polystyrene (EPS) geofoam techniques. An experimental model was carried out with dimensions depending on pipe diameter (D) and location, the used fill cover material was from sand and EPS blocks either embankment form, or within sand backfill as embedded layer. The pipe flexible is un-plasticized polyvinyl chloride (UPVC). A series of experiments have been carried out by using static surface loading on rectangular steel plate,where the load is distributed over the backfill. The behavior of sand backfill around the pipe was observed, and the displacement and strains of the pipe were measured. The experimental results showed that the embedded layer of EPS geofoam block embedded in sand for different techniques reduced the deformation of flexible buried pipe, with high efficiency and low coast compared with EPS geofoam only. The results reveal that, the most effective methods thatcanreduce the stress on buried flexible pipe with low cost were EPS encasement block with head void method, and EPS block embraces the upper part of pipe method

The development of a comprehensive framework for measuring business performance in construction

Business performance measurement has been the subject of considerable research over the past fifteen years. Most of this research has been triggered by the inadequacy of financial indicators and the increasing use of non-financial indicators. Consequently, companies have to choose from many available frameworks / methods to monitor their business performance such as the Balanced Scorecard, Excellence Models and industry key performance indicators (KPI). The choice of one framework / method over the others might omit important performance information, and the use of more than one simultaneously can cause confusion and the use of valuable time and resources. This paper describes the PhD research underway to develop a comprehensive business performance measurement framework for construction organizations. The research adopts a hypothetico-deductive approach that comprises two main stages. First, the framework is formulated from existing well-established frameworks in literature. The second stage is the empirical testing of the framework that uses triangulated methods for collecting and analysing data. The paper further discusses the scope of the research within the industry, and finally the use of the framework in measuring business performance and its interface with the construction KPI

Theoretical formulation of a framework for measuring business performance in construction

Business performance measurement, across industries, has significantly changed over the past two decades, integrating non-financial with financial measures. Moreover, the Egan and Latham reports have advocated performance improvement in the construction industry, with performance measurement being a key element. The purpose of this paper is to theoretically formulate a framework for measuring business performance in construction. The framework builds upon the well-established principles of the Balanced Scorecard and Business Excellence models. Formulation is based on integrating the criteria / perspectives of the founding frameworks into performance factors, and integrating the underlying logic. The formulation process is evaluated by comparing the proposed framework against the Balanced Scorecard, Excellence models, Total Quality Management frameworks in literature, and to the Performance Prism. The proposed framework is further adapted for construction companies and is shown to include the Construction Best Practice Programme - Key Performance Indicators that are based on Egan's industry report

The economics of currency risk

This article reviews the literature on currency and country risk with a focus on their macroeconomic origins and implications. A growing body of evidence shows that countries with safer currencies enjoy persistently lower interest rates and a lower required return to capital. As a result, they accumulate relatively more capital than countries with currencies that international investors perceive as risky. Whereas earlier research focused mainly on the role of currency risk in generating violations of uncovered interest parity and other financial anomalies, more recent evidence points to important implications for the allocation of capital across countries, the efficacy of exchange rate stabilization policies, the sustainability of trade deficits, and the spillovers of shocks across international borders.Accepted manuscrip