How do entrepreneurs fill institutional voids that prevail in emerging markets? By incorporating insights from both the political and family embeddedness perspectives, we argue that both political ...ties and family ties can compensate for gaps in the institutional infrastructure of emerging markets. Specifically, we propose and examine the partial substitutability of family ties for political ties as a means of filling institutional voids. Our empirical work based on Chinese private enterprises strongly supports this argument. We also find that the effective utilization of family ties is contingent on both family members’ motivation (willingness to use resources for the firm) and entrepreneurs’ mobilization (authority in the family to mobilize family members). This study bridges the literature on political ties and family ties to understand their respective costs and benefits and therefore advances our understanding of entrepreneurs’ networking strategies in emerging markets.
In this letter, we design non-orthogonal multiple access (NOMA) for multiple-antenna relaying networks. The receive antennas at the mobile users are assumed to adopt maximal ratio combining (MRC), ...whereas the transmit antenna that maximizes the instantaneous signal-to-noise ratio (SNR) at the relay is selected. The system outage performance is investigated and closed-form expressions for the exact outage probability are derived. Furthermore, we obtain the lower bound of the outage probability. Finally, simulation results are presented to show the correctness of the theoretical analysis and the superiority of NOMA.
Nonorthogonal multiple access (NOMA), which can improve the spectrum efficiency and system throughput compared with conventional orthogonal multiple access (OMA), has been regarded as a promising ...technique for the fifth-generation (5G) mobile communication network. In this paper, we consider a NOMA-based relaying networks over Nakagami-m fading channels, where the base station communicates with multiple mobile users simultaneously through the help of an amplify-and-forward (AF) relay. First, we study the system outage behavior, and closedform expressions for the exact outage probability and simple bounds of the outage probability are obtained, respectively. The analytical results are further evaluated in the high-signal-to-noiseratio (SNR) regime to explicitly characterize the diversity order of the network. Next, the ergodic sum rate achieved by the network is investigated, and expressions for the lower and upper bounds of the ergodic sum rate are derived. Finally, numerical examples are conducted to confirm the validity of our analysis and show a comparison of NOMA against conventional OMA networks. NOMA is reported to outperform conventional OMA and provide better spectral efficiency and user fairness.
We investigate the system performance of a nonorthogonal multiple access (NOMA) based downlink amplify-and-forward relay network over Nakagami-m fading channels with imperfect channel state ...information, where the base station and all users are provided with multiple antennas, while the relay is equipped with a single antenna. Two special conditions of interest (e.g., Nakagami-1, i.e., Rayleigh and Nakagami-2) are analyzed, and closed-form expression for the system outage probability is derived. Moreover, tight lower and upper bounds of the outage probability, and the outage probability in the high signal-to-interference-and-noise ratio regime, i.e., in the presence of error floor, which exists due to the channel estimation errors, are obtained. Finally, computer simulations are conducted to verify the accuracy of the numerical analysis and to confirm the superiority of the antenna selection and NOMA scheme.
The thermal diffusivity and thermal conductivity of four natural granitoid samples were simultaneously measured at high pressures (up to 1.5 GPa) and temperatures (up to 988 K) in a multi-anvil ...apparatus using the transient plane-source method. Experimental results show that thermal diffusivity and thermal conductivity decreased with increasing temperature (<600 K) and remain constant or slightly increase at a temperature range from 700 to 988 K. Thermal conductivity decreases 23-46% between room temperature and 988 K, suggesting typical manifestations of phonon conductivity. At higher temperatures, an additional radiative contribution is observed in four natural granitoids. Pressure exerts a weak but clear and positive influence on thermal transport properties. The thermal diffusivity and thermal conductivity of all granitoid samples exhibit a positive linear dependence on quartz content, whereas a negative linear dependence on plagioclase content appears. Combining these results with the measured densities, thermal diffusivity, and thermal conductivity, and specific heat capacities of end-member minerals, the thermal diffusivity and thermal conductivity and bulk heat capacities for granitoids predicted from several mixing models are found to be consistent with the present experimental data. Furthermore, by combining the measured thermal properties and surface heat flows, calculated geotherms suggest that the presence of partial melting induced by muscovite or biotite dehydration likely occurs in the upper-middle crust of southern Tibet. This finding provides new insights into the origin of low-velocity and high-conductivity anomaly zones revealed by geophysical observations in this region.
This paper investigates whether family firms display corporate giving practices significantly different from nonfamily firms. Our two-stage model theorizes, and finds empirical support from a survey ...of 3,075 Chinese private firms, that firms sensitive to institutional pressures (as a result of firm visibility and political linkages) are more likely to engage in philanthropy (stage 1) and to donate larger amounts (stage 2). In stage 1, family and nonfamily firms display similar conforming behaviors, aimed at maintaining sociopolitical legitimacy. In stage 2, family ownership intensifies the effect of institutional pressures on firms’ philanthropic giving, as reputational motives overlay legitimacy concerns. Our study integrates institutional analyses of socially responsible practices and family business theories to yield insights on the role of the family variable as a key moderator of institutional effects.
Non-orthogonal multiple access (NOMA), an emerging technology to improve system capacity and spectrum efficiency, has attracted significant attention. In this study, the authors propose a NOMA-based ...downlink cooperative cellular system, where the base station communicates with two paired mobile users simultaneously through the help of a half-duplex amplify-and-forward relay. The outage performance of the system is investigated and closed-form expressions for their respective exact and asymptotic outage scheme are derived. Furthermore, they study the ergodic sum rate of the two paired users and the upper bound of the ergodic sum rate is obtained. By comparing the NOMA with conventional multiple access (MA) via numerical simulations, they have shown that NOMA can obtain the same diversity order with conventional MA, and achieve nearly the same sum rate with conventional MA. Furthermore, NOMA can offer better spectral efficiency and user fairness since more users are served at the same time, frequency, and spreading code.
In this paper, a 5G energy-constrained network is considered, where a non-orthogonal multiple access (NOMA) scheme is applied at the multiple users. The outage probability and the ergodic rate are ...studied as two benchmarks to evaluate the system performance. First, a closed-form expression for the exact outage probability is derived. A lower bound of the outage probability is obtained and shown to predict well the system performance. In addition, the outage probability in the high signal-to-interference-plus-noise ratio (SINR) regime is studied to assess its upper limit while achieving the diversity order. Second, a closed-form expression for the upper bound of the ergodic rate is obtained. Then the ergodic rate in the high SINR regime is also analyzed. Finally, numerous computer simulations are performed to corroborate the superior performance of NOMA relative to orthogonal multiple access schemes and the validity of the derived analytical results.
The intrinsic integration of the nonorthogonal multiple access (NOMA) and reconfigurable intelligent surface (RIS) techniques is envisioned to be a promising approach to significantly improve both ...the spectrum efficiency and energy efficiency for future wireless communication networks. In this paper, the physical layer security (PLS) for a RIS-aided NOMA 6G networks is investigated, in which a RIS is deployed to assist the two "dead zone" NOMA users and both internal and external eavesdropping are considered. For the scenario with only internal eavesdropping, we consider the worst case that the near-end user is untrusted and may try to intercept the information of far-end user. A joint beamforming and power allocation sub-optimal scheme is proposed to improve the system PLS. Then we extend our work to a scenario with both internal and external eavesdropping. Two sub-scenarios are considered in this scenario: one is the sub-scenario without channel state information (CSI) of eavesdroppers, and another is the sub-scenario where the eavesdroppers' CSI are available. For the both sub-scenarios, a noise beamforming scheme is introduced to be against the external eavesdroppers. An optimal power allocation scheme is proposed to further improve the system physical security for the second sub-scenario. Simulation results show the superior performance of the proposed schemes. Moreover, it has also been shown that increasing the number of reflecting elements can bring more gain in secrecy performance than that of the transmit antennas.
Although many start-ups struggle to grow partly due to institutional voids in transitioning economies, empirical observations have contradicted this dominant view in the literature in that even with ...deficient formal institutions many economies (e.g., China) have high rates of entrepreneurship in recent years. To understand this paradox, we propose a politically contingent view of the relationship between the institutional environment and entrepreneurs' reinvestment in their business. Our empirical study of entrepreneurs in China shows that the impact of institutional deterioration on entrepreneurial reinvestment substantially hinges on entrepreneurs' political connections. As such, institutional deterioration does not reduce entrepreneurial reinvestment for all entrepreneurs; rather, when entrepreneurs have political connections they are willing to reinvest in their business despite a weakening institutional environment. Our framework suggests that in an environment perceived as harsh to business, political connections can encourage entrepreneurs to see opportunities for growth. In contrast, entrepreneurs that lack political connections will mainly see threats in a deteriorating institutional environment and thus, limit their business reinvestment.
•The impact of institutional deterioration on entrepreneurial reinvestment depends on entrepreneurs’ political connections•Entrepreneurs with political connections are willing to reinvest despite a weakening institutional environment•Entrepreneurs that lack political connections limit reinvestment in a deteriorating institutional environment
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