Financiers of the world, disunite

Diversity across banks and other financial firms promotes a resilient financial system because differing risk profiles reduce the likelihood of systemic crises caused by shared economic shocks. Consolidation and uniformity among banks and other financial intermediaries do the opposite. ; Yet some have suggested that any policy steps to reverse the financial system’s dramatic consolidation might yield little stability benefit because herd-like behavior among financial firms could still reduce diversity and mitigate any strengthening. If these firms moved in concert, the argument goes, they would make themselves susceptible to common shocks as if they had adopted a more consolidated structure. ; Countering this concern are indications that financial firms, when allowed to flourish, display stability-enhancing diversity. We find that hedge funds—despite a reputation for high-risk strategies and correlated behavior—recently have exhibited significant strategic dissimilarities, to the benefit of system stability.Financial risk management

Liquidity, momentum and price bubbles : evidence from the UK

The asset pricing anomalies have existed in the UK stock market for a long time. This thesis aims to study different liquidity measures, liquidity commonality, systematic liquidity risk, different momentum trading strategies, asset pricing risks with momentum, investor behaviours with momentum and the causal link between financial crisis and asset pricing anomalies using various methods and tests. The first empirical chapter examines the performance of the standard Sharpe- Lintner CAPM, the Fama-French three factor model, and the four factor model of Carhart (1997) both with, and without, the first component of multiple illiquidity measures. The results show that no individual illiquidity proxy outperforms the others, and further that the illiquidity proxies have a systematic common illiquidity component. The results also reveal that the inclusion of the illiquidity factor in the capital asset pricing model plays a significant role in explaining the crosssectional variation in stock returns. The second empirical chapter analyses the relationship between momentum profits and stock market illiquidity. This study finds negative and significant relationship between aggregate market illiquidity and momentum profits. The model applied in this chapter captures significant bounce in varying beta coe cients changing over time. The analysis also indicates that the stocks associated with high liquidity performs better relative to illiquid stocks under systemic shocks. The final empirical chapter investigated momentum anomaly and the hypothesis that individual investors trade differently from institutional investors and significantly overreact to economic shocks, creating destabilising effect in the stock market. The results reveal that stock market ineffi ciency is driven and dominated by individual investors' anchoring and adjustment biases as well as institutional investors' cognitive biases. There are several implications for this work. The findings may be useful for both individual and institutional investors and regulators in similar markets beyond the UK, for example, the other European markets. In this study, we show that abnormal stock performance during liquidity crisis is, in part, predictable, and investors can construct portfolios of stocks that better withstand liquidity shocks. For individual investors, they can maximise their profits by holding momentum portfolios at a short horizon. For institutional investors, they might take advantage of professional expertise in making abnormal profits. Policy makers are expected to pay special attention to the differences in trading by financial institutions and individual investors

Fast antijamming timing acquisition using multilayer synchronization sequence

Pseudonoise (PN) sequences are widely used as preamble sequences to establish timing synchronization in military wireless communication systems. At the receiver, searching and detection techniques, such as the full parallel search (FPS) and the serial search (SS), are usually adopted to acquire correct timing position. However, the synchronization sequence has to be very long to combat jamming that reduces the signal-to-noise ratio (SNR) to an extremely low level. In this adverse scenario, the FPS scheme becomes too complex to implement, whereas the SS method suffers from the drawback of long mean acquisition time (MAT). In this paper, a fast timing acquisition method is proposed, using the multilayer synchronization sequence based on cyclical codes. Specifically, the transmitted preamble is the Kronecker product of Bose–Chaudhuri-Hocquenghem (BCH) codewords and PN sequences. At the receiver, the cyclical nature of BCH codes is exploited to test only a part of the entire sequence, resulting in shorter acquisition time. The algorithm is evaluated using the metrics of MAT and detection probability (DP). Theoretical expressions of MAT and DP are derived from the constant false-alarm rate (CFAR) criterion. Theoretical analysis and simulation results show that our proposed scheme dramatically reduces the acquisition time while achieving similar DP performance and maintaining a reasonably low real-time hardware implementation complexity, in comparison with the SS schem

Downlink Small-cell Base Station Cooperation Strategy in Fractal Small-cell Networks

Coordinated multipoint (CoMP) communications are considered for the fifth-generation (5G) small-cell networks as a tool to improve the high data rates and the cell-edge throughput. The average achievable rates of the small-cell base stations (SBS) cooperation strategies with distance and received signal power constraints are respectively derived for the fractal small-cell networks based on the anisotropic path loss model. Simulation results are presented to show that the average achievable rate with the received signal power constraint is larger than the rate with a distance constraint considering the same number of cooperative SBSs. The average achievable rate with distance constraint decreases with the increase of the intensity of SBSs when the anisotropic path loss model is considered. What's more, the network energy efficiency of fractal smallcell networks adopting the SBS cooperation strategy with the received signal power constraint is analyzed. The network energy efficiency decreases with the increase of the intensity of SBSs which indicates a challenge on the deployment design for fractal small-cell networks.Comment: 5 figures. Accepted by Globecom 201