629 research outputs found

    Indirect Financial Loss of Phishing to Global Market

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    This research studies the indirect financial impact of phishing announcements on firm value. Using about 3,000 phishing announcements, we showed that phishing has a significantly negative impact on firms regardless of their size. We also discovered that place of incorporation, type of ownership, industry, and time are significant factors exacerbating the impact. Our research findings may give some insights to industrial practitioners about attitude of investors towards phishing. Compared to other similar event studies, our research has also made several significant breakthroughs. Firstly, we used the largest data set ever in prior event studies. Secondly, our research is the first to analyze global phenomena concerning phishing. Thirdly, we enhanced the robustness of a regression model by introducing the criterion of selection of best fit market index based on R square. We believe that our research can add value to the literature in the subjects of phishing research and event studies

    Magnetic domain studies of permalloy wire-based structures with junctions

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    Permalloy (Ni-80 Fe-20) wire-based structures (30 nm thick and 1 . w . 10 mum wide) with junctions (crosses, networks, H-shapes, rectangular chains and ring chains) prepared on a GaAs (100) substrate were observed in both their demagnetized and remanent states by magnetic force microscopy (MFM) in order to investigate the role of junction geometry in domain formation, Except in ring chains, two classes of domain configuration are found at the junction: (i) a domain wall-like feature due to abrupt spin rotation and (ii) a triangle-shape domain consistent with a flux closure configuration, Ring chains, on the other hand, form vortex domains at every other junction. The MFM observations are compared with micromagnetic calculations which qualitatively support the magnetic domain configurations

    Magnetization reversal in mesoscopic Ni80Fe20 wires: A magnetic domain launching device

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    The magnetization reversal process in mesoscopic permalloy (Ni80Fe20) wire structures has been investigated using scanning Kerr microscopy, magnetic force microscopy (MFM) and micromagnetic calculations. We find that the junction offers a site for reversed domain wall nucleation in the narrow part of the wires. As a consequence, the switching field is dominated by the domain nucleation field and the junction region initiates reversal by the wall motion following the nucleation of domains. Our results suggest the possibility of designing structures that can be used to “launch” reverse domains in narrow wires within a controlled field rang

    Applications and design issues for mobile agents in wireless sensor networks

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    Optimal VM placement in data centres with architectural and resource constraints

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    Recent advance in virtualisation technology enables service provisioning in a flexible way by consolidating several virtual machines (VMs) into a single physical machine (PM). The inter-VM communications are inevitable when a group of VMs in a data centre provide services in a collaborative manner. With the increasing demands of such intra-data-centre traffics, it becomes essential to study the VM-to-PM placement such that the aggregated communication cost within a data centre is minimised. Such optimisation problem is proved NP-hard and formulated as an integer programming with quadratic constraints in this paper. Different from existing work, our formulation takes into consideration of data-centre architecture, inter-VM traffic pattern, and resource capacity of PMs. Furthermore, a heuristic algorithm is proposed and its high efficiency is extensively validated

    Understanding the Spatial Clustering of Severe Acute Respiratory Syndrome (SARS) in Hong Kong

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    We applied cartographic and geostatistical methods in analyzing the patterns of disease spread during the 2003 severe acute respiratory syndrome (SARS) outbreak in Hong Kong using geographic information system (GIS) technology. We analyzed an integrated database that contained clinical and personal details on all 1,755 patients confirmed to have SARS from 15 February to 22 June 2003. Elementary mapping of disease occurrences in space and time simultaneously revealed the geographic extent of spread throughout the territory. Statistical surfaces created by the kernel method confirmed that SARS cases were highly clustered and identified distinct disease “hot spots.” Contextual analysis of mean and standard deviation of different density classes indicated that the period from day 1 (18 February) through day 16 (6 March) was the prodrome of the epidemic, whereas days 86 (15 May) to 106 (4 June) marked the declining phase of the outbreak. Origin-and-destination plots showed the directional bias and radius of spread of superspreading events. Integration of GIS technology into routine field epidemiologic surveillance can offer a real-time quantitative method for identifying and tracking the geospatial spread of infectious diseases, as our experience with SARS has demonstrated

    Wave Propagation in Gravitational Systems: Late Time Behavior

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    It is well-known that the dominant late time behavior of waves propagating on a Schwarzschild spacetime is a power-law tail; tails for other spacetimes have also been studied. This paper presents a systematic treatment of the tail phenomenon for a broad class of models via a Green's function formalism and establishes the following. (i) The tail is governed by a cut of the frequency Green's function G~(ω)\tilde G(\omega) along the −-~Im~ω\omega axis, generalizing the Schwarzschild result. (ii) The ω\omega dependence of the cut is determined by the asymptotic but not the local structure of space. In particular it is independent of the presence of a horizon, and has the same form for the case of a star as well. (iii) Depending on the spatial asymptotics, the late time decay is not necessarily a power law in time. The Schwarzschild case with a power-law tail is exceptional among the class of the potentials having a logarithmic spatial dependence. (iv) Both the amplitude and the time dependence of the tail for a broad class of models are obtained analytically. (v) The analytical results are in perfect agreement with numerical calculations

    The Importance of Hydration in Wound Healing: Reinvigorating the clinical perspective

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    Balancing skin hydration levels is important as any disruption in skin integrity will result in disturbance of the dermal water balance. The discovery that a moist wound healing environment actively supports the healing response when compared to a dry environment highlights the importance of water and good hydration levels for optimal wound healing. The benefits of “wet” or “hyper-hydrated” wound healing appears to offer benefits that are similar to those offered by moist wound healing over wounds healing in a dry environment. This suggests that the presence of free water itself during wound healing may not be detrimental to healing but that any adverse effects of wound fluid on tissues is more likely related to the biological components contained within chronic wound exudate (e.g. elevated protease levels). Appropriate dressings applied to wounds must be able to absorb not only the exudate but also retain this excess fluid together with its protease solutes while concurrently preventing desiccation. This is particularly important in the case of chronic wounds where peri-wound skin barrier properties are compromised and there is increased permeation across the injured skin barrier. This review discusses the importance of appropriate levels of hydration in skin with a particular focus on the need for optimal hydration levels for effective healing

    PAPR reduction using iterative clipping/filtering and ADMM approaches for OFDM-based mixed-numerology systems

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    Mixed-numerology transmission is proposed to support a variety of communication scenarios with diverse requirements. However, as the orthogonal frequency division multiplexing (OFDM) remains as the basic waveform, the peak-to average power ratio (PAPR) problem is still cumbersome. In this paper, based on the iterative clipping and filtering (ICF) and optimization methods, we investigate the PAPR reduction in the mixed-numerology systems. We first illustrate that the direct extension of classical ICF brings about the accumulation of inter-numerology interference (INI) due to the repeated execution. By exploiting the clipping noise rather than the clipped signal, the noise-shaped ICF (NS-ICF) method is then proposed without increasing the INI. Next, we address the in-band distortion minimization problem subject to the PAPR constraint. By reformulation, the resulting model is separable in both the objective function and the constraints, and well suited for the alternating direction method of multipliers (ADMM) approach. The ADMM-based algorithms are then developed to split the original problem into several subproblems which can be easily solved with closed-form solutions. Furthermore, the applications of the proposed PAPR reduction methods combined with filtering and windowing techniques are also shown to be effective

    Information-sharing outage-probability analysis of vehicular networks

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    In vehicular networks, information dissemination/sharing among vehicles is of salient importance. Although diverse mechanisms have been proposed in the existing literature, the related information credibility issues have not been investigated. Against this background, in this paper, we propose a credible information-sharing mechanism capable of ensuring that the vehicles do share genuine road traffic information (RTI). We commence with the outage-probability analysis of information sharing in vehicular networks under both a general scenario and a specific highway scenario. Closed-form expressions are derived for both scenarios, given the specific channel settings. Based on the outage-probability expressions, we formulate the utility of RTI sharing and design an algorithm for promoting the sharing of genuine RTI. To verify our theoretical analysis and the proposed mechanism, we invoke a real-world dataset containing the locations of Beijing taxis to conduct our simulations. Explicitly, our simulation results show that the spatial distribution of the vehicles obeys a Poisson point process (PPP), and our proposed credible RTI sharing mechanism is capable of ensuring that all vehicles indeed do share genuine RTI with each other
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