853 research outputs found

    Optical grooming in OFDM-based elastic optical networks

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    Optimal Diffusion Strategy of Advertising Using a Facebook Application

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    In 2007, Facebook made a momentous decision to open its platform for independent applications. After that, numerous applications are designed and deployed. From a business perspective, a Facebook application has the characteristics of low development cost and strong word-of-mouth effect, which provide an ideal alternative to traditional advertising format. This paper reveals the diffusion pattern of three leading Facebook applications and concludes that the classic Bass diffusion model can be applied to the diffusion process. Based on Bass model, we further propose a diffusion strategy of advertising using a Facebook application. We find that for a given amount of advertising budget, to achieve a maximum percentage of user installations out of the target population of the application, there exists a unique solution to allocate the budget optimally between activities promoting innovation and imitation effects. Numerical examples are provided to illustrate the optimal solution

    A Symbol in Mass Production: Ruyi Images in the Inner and Outer Cities Under the Qianlong Reign

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    Qianlong's predilection for the Chinese auspicious symbol ruyi was satisfied by court artists and echoed in the country at large by the mass production of the New Year Picture workshops. This imperial cult manifests Qianlong's authority on the country and the Han subjects' recognition of the Manchu emperor

    VERTICAL DIFFERENTIATION IN THE MARKET FOR SECURITY SOFTWARE

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    The market for security software has witnessed an unprecedented growth in recent years. A closer examination of this market reveals that, unlike a traditional software market, the use of vertical differentiation strategy is quite limited in this market. In this paper, we develop a quantitative model to explore the possible reason. Our model identifies a negative network externality effect as the primary reason for this divergence. Using our model, we show that, in this market, the vertical differentiation strategy would never be employed by a monopolist. We then extend our analysis to a duopoly competition and find that, although vertical differentiation may be adopted if the cost of development is sufficiently high, due to the presence of the negative network externality, the feasible region for differentiation is much more restricted when compared to a traditional market

    Working Students and Their Academic Performance – A Decision Tree Analysis

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    In this study, a decision tree analysis is conducted to identify the effects from working. The result shows that student age is the first major indicator for better grade regardless of working status. Then, the factor of students’ self-perception on the effect of working on academic performance matters a lot. A pessimistic student, who believes in the negative impact of working on studying, needs a balanced combination of course work and working load. However, for an optimistic student, academic standing is important. Senior students with a positive perception on working are more likely to validate this perception by good academic performance. While, for students in other academic standings, working for a job relevant to major can help. Otherwise, a moderate level of working load is still recommended. The analysis approach can be easily applied to any academic counselling: to identify when working intensity can matter, which group of students may be more vulnerable to a negative impact of working, and what working aspects may play a role in academic performance

    Short and long range relation based spatio-temporal transformer for micro-expression recognition

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    The authors would like to thank the China Scholarship Council – University of St Andrews Scholarships (No.201908060250) funds L. Zhang for her PhD. This work is funded by the National Key Research and Development Project of China under Grant No. 2019YFB1312000, the National Natural Science Foundation of China under Grant No. 62076195, and the Fundamental Research Funds for the Central Universities under Grant No. AUGA5710011522.Being spontaneous, micro-expressions are useful in the inference of a person's true emotions even if an attempt is made to conceal them. Due to their short duration and low intensity, the recognition of micro-expressions is a difficult task in affective computing. The early work based on handcrafted spatio-temporal features which showed some promise, has recently been superseded by different deep learning approaches which now compete for the state of the art performance. Nevertheless, the problem of capturing both local and global spatio-temporal patterns remains challenging. To this end, herein we propose a novel spatio-temporal transformer architecture – to the best of our knowledge, the first purely transformer based approach (i.e. void of any convolutional network use) for micro-expression recognition. The architecture comprises a spatial encoder which learns spatial patterns, a temporal aggregator for temporal dimension analysis, and a classification head. A comprehensive evaluation on three widely used spontaneous micro-expression data sets, namely SMIC-HS, CASME II and SAMM, shows that the proposed approach consistently outperforms the state of the art, and is the first framework in the published literature on micro-expression recognition to achieve the unweighted F1-score greater than 0.9 on any of the aforementioned data sets.PostprintPostprintPeer reviewe

    The simultaneous repair of an Irreducible Diaphragmatic Hernia while carrying out a Cesarean Section

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    AbstractINTRODUCTIONDiaphragmatic hernia complicating pregnancy rarely occurs while it is frequently misdiagnosed.PRESENTATION OF CASEA pregnant woman who had suffered from recurrent right upper-quadrant abdominal pain for 4 months was hospitalized near full term because the unrelieved abdominal pain was so severe that she couldn’t lie down. Following the emergency caesarean, we found a part of the transverse colon and a part of omentum were trapped in the thorax through a 3cm by 3cm laceration in the patient's diaphragm. We removed all trapped intestine which was about 40cm long and repaired diaphragmatic hernia at the same time.DISCUSSIONRadiography is useful to diagonisis diaphragmatic hernia, but it had little use for pregnant women. An irreducible diaphragmatic hernia represent a surgical emergency irrespective of fetal maturity. In our case, she had her hernia repaired just during caesarean section by laparotomy.CONCLUSIONCareful examination and a timely operation are needed to treat diaphragmatic hernia complicating pregnancy

    A Symbol in Mass Production: Ruyi Images in the Inner and Outer Cities Under the Qianlong Reign

    Get PDF
    Qianlong's predilection for the Chinese auspicious symbol ruyi was satisfied by court artists and echoed in the country at large by the mass production of the New Year Picture workshops. This imperial cult manifests Qianlong's authority on the country and the Han subjects' recognition of the Manchu emperor
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