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Due to its high mobility and flexible deployment, unmanned aerial vehicle (UAV) is drawing unprecedented interest in both military and civil applications to enable agile and ubiquitous connectivity. Mainly operating in an open env...
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Due to its high mobility and flexible deployment, unmanned aerial vehicle (UAV) is drawing unprecedented interest in both military and civil applications to enable agile and ubiquitous connectivity. Mainly operating in an open environment, UAV communications benefit from dominant line-of-sight links; however, this on the other hand renders the communications more vulnerable to malicious attacks. Recently, physical layer security (PLS) has been introduced to UAV systems as an important complement to the conventional cryptography-based approaches. In this paper, a comprehensive survey on the current achievements of UAV-PLS is conducted. We first introduce the basic concepts including typical static/mobile UAV deployment scenarios, the unique air-to-ground channel and aerial nodes distribution models, as well as various roles that a UAV may act when PLS is concerned. Then, we start by reviewing the secrecy performance analysis and enhancing techniques for statically deployed UAV systems, and extend the discussion to the more general scenario where the UAVs' mobility is further exploited. For both cases, respectively, we summarize the commonly adopted methodologies, then describe important works in the literature in detail. Finally, potential research directions and challenges are discussed to provide an outlook for future works in the area of UAV-PLS.
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Abstract This paper examines the impact of home country institutions on corporate social responsibility (CSR) of multinational enterprises from emerging markets (EM-MNEs). Taking the Belt and Road Initiative (BRI) as an example an...
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Abstract This paper examines the impact of home country institutions on corporate social responsibility (CSR) of multinational enterprises from emerging markets (EM-MNEs). Taking the Belt and Road Initiative (BRI) as an example and using a sample with 2052 firm-year observations from China over the period 2008–2018, we find that the BRI exerts a positive and significant effect on overall CSR of Chinese MNEs involved in the BRI and the positive effect is stronger for Chinese state-owned MNEs. In addition, only two dimensions of CSR (Employee Relations and Products) are improved significantly under the pressure of BRI. Finally, we examine the interactive effect of home- and host- country institutions on Chinese MNEs’ CSR and find the positive impact of the BRI on MNEs’ CSR performance is stronger in host countries with a higher level of CSR related institutional pressure. These results provide practical suggestions for the Chinese government and MNEs to further improve CSR under the BRI, and enrich our understanding of the interactive effect between home- and host-country institutions on enhancing Chinese MNEs’ reputation and promoting regional cooperation with countries along the BRI.
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Abstract While political connections are a critical non‐market strategy for emerging market firms (EMFs) to achieve success, how they affect EMFs’ outward foreign direct investment (OFDI) remains controversial. Building on the i...
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Abstract While political connections are a critical non‐market strategy for emerging market firms (EMFs) to achieve success, how they affect EMFs’ outward foreign direct investment (OFDI) remains controversial. Building on the institution‐based view, we examine how home‐country political connections facilitate or impede EMFs’ OFDI. Using a panel dataset of listed private firms in China, we find that home political connections have an inverted U‐shaped effect on firms’ OFDI level; the effect becomes flatter as pro‐market reforms proceed in the home country, but becomes steeper for firms with strong technological capability. By revealing a nonlinear effect, our study helps reconcile inconsistencies regarding the role of home political connections in OFDI and has important implications for EMFs’ internationalization.
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Maximizing growth and survival in the face of a complex, time-varying environment is a common problem for single-celled organisms in the wild. When offered two different sugars as carbon sources, microorganisms first consume the p...
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Maximizing growth and survival in the face of a complex, time-varying environment is a common problem for single-celled organisms in the wild. When offered two different sugars as carbon sources, microorganisms first consume the preferred sugar, then undergo a transient growth delay, the “diauxic lag,” while inducing genes to metabolize the less preferred sugar. This delay is commonly assumed to be an inevitable consequence of selection to maximize use of the preferred sugar. Contrary to this view, we found that many natural isolates of Saccharomyces cerevisiae display short or nonexistent diauxic lags when grown in mixtures of glucose (preferred) and galactose. These strains induce galactose utilization (GAL) genes hours before glucose exhaustion, thereby “preparing” for the transition from glucose to galactose metabolism. The extent of preparation varies across strains, and seems to be determined by the steady-state response of GAL genes to mixtures of glucose and galactose rather than by induction kinetics. Although early GAL gene induction gives strains a competitive advantage once glucose runs out, it comes at a cost while glucose is still present. Costs and benefits correlate with the degree of preparation: strains with higher expression of GAL genes prior to glucose exhaustion experience a larger upfront growth cost but also a shorter diauxic lag. Our results show that classical diauxic growth is only one extreme on a continuum of growth strategies constrained by a cost–benefit tradeoff. This type of continuum is likely to be common in nature, as similar tradeoffs can arise whenever cells evolve to use mixtures of nutrients.
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Incorporating the global production network approach and competitor analysis, this paper establishes an analytical framework with two hypotheses for the role of foreign multinational enterprises (FMNEs) in indigenous firms' export...
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Incorporating the global production network approach and competitor analysis, this paper establishes an analytical framework with two hypotheses for the role of foreign multinational enterprises (FMNEs) in indigenous firms' exports and domestic sales. First, the presence of FMNEs as a whole is likely to have a negative impact on indigenous firms' domestic sales but a simultaneous positive impact on their exports in an emerging economy like China. Second, the presence of MNEs from Hong Kong, Macau and Taiwan (HMT MNEs) is more likely to generate this pattern of impact than MNEs from other countries (Other FMNEs). The foreign direct investment-led export strategy contributed to the dominance of the scenario described by the first hypothesis in China, while a higher degree of market commonality and resource similarity of HMT MNEs with that of indigenous Chinese firms than Other FMNEs leads to the second hypothesis. These novel hypotheses are tested and supported by a very large and recent firm-level panel dataset from Chinese manufacturing.
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Aim/Purpose There is ample evidence that team processes matter more than the characteristics of individual team members; unfortunately, very few empirical studies have examined communication process variables closely or tied them ...
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Aim/Purpose There is ample evidence that team processes matter more than the characteristics of individual team members; unfortunately, very few empirical studies have examined communication process variables closely or tied them to team outcomes. Background The University of Miami Laboratory for Integrated Knowledge (U-LINK) is a pilot funding mechanism that was developed and implemented based on empirically-established best practices established in the literature on the Science of Team Science (SciTS). In addition to addressing grand societal challenges, teams engaged in processes designed to enhance the process of “teaming”. This study uses the Inputs-Mediator-Outputs-Inputs (IMOI) model as a blueprint for an investigation into how team communication processes (shared communication, shared leadership, formal meetings, informal meetings) influence intermediary team processes (goal clarity, role ambiguity, process clarity, trust) and team outcomes (team satisfaction, team productivity).Methodology Monte Carlo methodologies were used to explore both longitudinal self-report (survey of communication and team outcome variables) data and objective data on scholarly productivity, collected from seventy-eight members of eleven realworld intact interdisciplinary teams to explore how team communication processes affect team outcomes. Contribution This study is among the few that centers communication practice and processes in the operationalization and measurement of its constructs and which provides a test of hypotheses centered on key questions identified in the literature. Findings Communication practices are important to team processes and outcomes. Shared communication and informal meetings were associated with increased team satisfaction and increased research productivity. Shared leadership was associated with increased research productivity, as well as improved process and goal clarity. Formal meetings were associated with increased goal clarity and decreased role ambiguity. Recommendations for Practitioners Team trainings should focus on communication practices that improve shared leadership and shared communication. Additionally, teaching best practices for formal (task-oriented) meetings can help improve goal clarity and decrease role ambiguity. Finally, the benefits of informal socializing should be recognized, and teams should be encouraged to meet informally (socially, without formal task agendas). Recommendations for Researchers Studying intact interdisciplinary research teams requires innovative methods and clear specification of variables. Challenges associated with access to limited numbers of teams should not preclude engaging in research as each study contributes to our larger body of knowledge of the factors that influence the success of interdisciplinary research teams. Impact on Society The success of interdisciplinary teams can be improved with trainings focused on communication skills. The success of these teams is critical to addressing societies’ most pressing challenges, and careful consideration of team processes is critical to that success. Future Research Future research should examine different team formation and funding mechanisms and extend observation and data collection for longer periods of time.
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This paper is devoted to the mathematical analysis of the diffraction of an electromagnetic plane wave by a biperiodic structure. The wave propagation is governed by the time-domain Maxwell equations in three dimensions. The metho...
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This paper is devoted to the mathematical analysis of the diffraction of an electromagnetic plane wave by a biperiodic structure. The wave propagation is governed by the time-domain Maxwell equations in three dimensions. The method of a compressed coordinate transformation is proposed to reduce equivalently the diffraction problem into an initial-boundary value problem formulated in a bounded domain over a finite time interval. The reduced problem is shown to have a unique weak solution by using the constructive Galerkin method. The stability and a priori estimates with explicit time dependence are established for the weak solution.
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The complicated interactions between genetic background, environment and lifestyle factors make it difficult to study the genetic basis of complex phenotypes, such as cognition and anxiety levels, in humans. However, environmental...
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The complicated interactions between genetic background, environment and lifestyle factors make it difficult to study the genetic basis of complex phenotypes, such as cognition and anxiety levels, in humans. However, environmental and other factors can be tightly controlled in mouse studies. The Collaborative Cross (CC) is a mouse genetic reference population whose common genetic and phenotypic diversity is on par with that of humans. Therefore, we leveraged the power of the CC to assess 52 behavioral measures associated with locomotor activity, anxiety level, learning and memory. This is the first application of the CC in novel object recognition tests, Morris water maze tasks, and fear conditioning tests. We found substantial continuous behavioral variations across the CC strains tested, and mapped six quantitative trait loci (QTLs) which influenced these traits, defining candidate genetic variants underlying these QTLs. Overall, our findings highlight the potential of the CC population in behavioral genetic research, while the identified genomic loci and genes driving the variation of relevant behavioral traits provide a foundation for further studies.
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In nature, microbes often need to "decide" which of several available nutrients to utilize, a choice that depends on a cell’s inherent preference and external nutrient levels. While natural environments can have mixtures of diffe...
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In nature, microbes often need to "decide" which of several available nutrients to utilize, a choice that depends on a cell’s inherent preference and external nutrient levels. While natural environments can have mixtures of different nutrients, phenotypic variation in microbes’ decisions of which nutrient to utilize is poorly studied. Here, we quantified differences in the concentration of glucose and galactose required to induce galactose-responsive (GAL) genes across 36 wild S. cerevisiae strains. Using bulk segregant analysis, we found that a locus containing the galactose sensor GAL3 was associated with differences in GAL signaling in eight different crosses. Using allele replacements, we confirmed that GAL3 is the major driver of GAL induction variation, and that GAL3 allelic variation alone can explain as much as 90% of the variation in GAL induction in a cross. The GAL3 variants we found modulate the diauxic lag, a selectable trait. These results suggest that ecological constraints on the galactose pathway may have led to variation in a single protein, allowing cells to quantitatively tune their response to nutrient changes in the environment.
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Peculiarity oriented mining (POM), aimed at discovering peculiarity rules hidden in a dataset, is a data mining method. Peculiarity factor (PF) is one of the most important concepts in POM. In this paper, it is proved that PF can ...
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Peculiarity oriented mining (POM), aimed at discovering peculiarity rules hidden in a dataset, is a data mining method. Peculiarity factor (PF) is one of the most important concepts in POM. In this paper, it is proved that PF can accurately characterize the peculiarity of data sampled from a normal distribution. However, for a general one-dimensional distribution, it does not have the property. A local version of PF, called LPF, is proposed to solve the difficulty. LPF can effectively describe the peculiarity of data sampled from a continuous one-dimensional distribution. Based on LPF, a framework of local peculiarity oriented mining is presented, which consists of two steps, namely, peculiar data identification and peculiar data analysis. Two algorithms for peculiar data identification and a case study of peculiar data analysis are given to make the framework practical. Experiments on several benchmark datasets show their good performance.
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