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A Theory of Ratio Selection—Lattice Model for Obligate Mutualism
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作者 Kei-Ichi Tainaka Tsuyoshi Hashimoto 《Open Journal of Ecology》 2016年第6期303-311,共9页
Mutualisms are cooperative interactions between members of different species. We focus on obligate mutualism, where each species cannot survive without the other. From a theoretical aspect, obligate mutualism is simil... Mutualisms are cooperative interactions between members of different species. We focus on obligate mutualism, where each species cannot survive without the other. From a theoretical aspect, obligate mutualism is similar to the relationship between male and female. Empirical data indicate a sex-ratio selection: male and female have a specific ratio in their population sizes. In the present paper, we apply lattice model to obligate mutualism between two species, and present a theory of “ratio selection” which is a generalization of sex-ratio selection. Computer simulations are carried out by two methods: local and global interactions. In the former, interactions occur between neighbouring cells, while in the latter they occur between any pair of cells. Simulations in both interactions show the so-called Allee effect: both species can survive, when both densities are large in some extent. However, we find a large difference between local and global simulations. In the case of local interaction, restriction for survival is found to be extremely severe compared to global interaction. Both species require a proper ratio for their sustainability. This result leads to the theory of ratio selection: when interaction occurs locally, the ratio of both species is uniquely determined. We discuss that the ratio selection explains not only the evolution of endosymbionts from free-living ancestors but also the evolution from endosymbionts to organelles. 展开更多
关键词 Obligate Mutualism Population Dynamics ratio selection Allee Effect Lattice Model Sex-ratio selection ENDOSYMBIOSIS
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Riemann problem for one-dimensional binary gas enhanced coalbed methane process
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作者 Changfu Tang,) and Xiaodong Wang School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083, China 《Theoretical & Applied Mechanics Letters》 CAS 2011年第6期41-44,共4页
With an extended Langmuir isotherm, a Riemann problem for one-dimensional binary gas enhanced coalbed methane (ECBM) process is investigated. A new analytical solution to the Riemann problem, based on the method of ch... With an extended Langmuir isotherm, a Riemann problem for one-dimensional binary gas enhanced coalbed methane (ECBM) process is investigated. A new analytical solution to the Riemann problem, based on the method of characteristics, is developed by introducing a gas selectivity ratio representing the gas relative sorption affinity. The influence of gas selectivity ratio on the enhanced coalbed methane processes is identified. 展开更多
关键词 Riemann problem binary gas enhanced coalbed methane method of characteristics gas selectivity ratio
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On the System Performance of Mobile Edge Computing in an Uplink NOMA WSN With a Multiantenna Access Point Over Nakagami-m Fading 被引量:1
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作者 Van-Truong Truong Van Nhan Vo +1 位作者 Dac-Binh Ha Chakchai So-In 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第4期668-685,共18页
In this paper,we study the system performance of mobile edge computing(MEC)wireless sensor networks(WSNs)using a multiantenna access point(AP)and two sensor clusters based on uplink nonorthogonal multiple access(NOMA)... In this paper,we study the system performance of mobile edge computing(MEC)wireless sensor networks(WSNs)using a multiantenna access point(AP)and two sensor clusters based on uplink nonorthogonal multiple access(NOMA).Due to limited computation and energy resources,the cluster heads(CHs)offload their tasks to a multiantenna AP over Nakagami-m fading.We proposed a combination protocol for NOMA-MEC-WSNs in which the AP selects either selection combining(SC)or maximal ratio combining(MRC)and each cluster selects a CH to participate in the communication process by employing the sensor node(SN)selection.We derive the closed-form exact expressions of the successful computation probability(SCP)to evaluate the system performance with the latency and energy consumption constraints of the considered WSN.Numerical results are provided to gain insight into the system performance in terms of the SCP based on system parameters such as the number of AP antennas,number of SNs in each cluster,task length,working frequency,offloading ratio,and transmit power allocation.Furthermore,to determine the optimal resource parameters,i.e.,the offloading ratio,power allocation of the two CHs,and MEC AP resources,we proposed two algorithms to achieve the best system performance.Our approach reveals that the optimal parameters with different schemes significantly improve SCP compared to other similar studies.We use Monte Carlo simulations to confirm the validity of our analysis. 展开更多
关键词 Mobile edge computing(MEC) Nakagami-m fading OFFLOADING selection combining(SC)/maximal ratio combining(MRC) successful computation probability(SCP) uplink nonortho-gonal multiple access(NOMA) wireless sensor networks(WSNs)
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Adaptive IF selection and IQ mismatch compensation in a low-IF GSM receiver 被引量:1
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作者 张成 王丽芳 +1 位作者 谈熙 闵昊 《Journal of Semiconductors》 EI CAS CSCD 2012年第6期71-78,共8页
This paper presents an algorithm that can adaptively select the intermediate frequency(IF) and compensate the IQ mismatch according to the power ratio of the adjacent channel interference to the desired signal in a ... This paper presents an algorithm that can adaptively select the intermediate frequency(IF) and compensate the IQ mismatch according to the power ratio of the adjacent channel interference to the desired signal in a low-IF GSM receiver.The IF can be adaptively selected between 100 and 130 kHz.Test result shows an improvement of phase error from 6.78°to 3.23°.Also a least mean squares(LMS) based IQ mismatch compensation algorithm is applied to improve image rejection ratio(IRR) for the desired signal along with strong adjacent channel interference.The IRR is improved from 29.1 to 44.3 dB in measurement.The design is verified in a low-IF GSM receiver fabricated in SMIC 0.13μm RF CMOS process with a working voltage of 1.2 V. 展开更多
关键词 low-IF adaptive selection phase error IRR LMS algorithm power ratio
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Pd/C modified with Sn catalyst for liquid-phase selective hydrogenation of maleic anhydride to gamma-butyrolactone 被引量:5
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作者 Rongrong Li Jia Zhao +1 位作者 Deman Han Xiaonian Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第6期1330-1335,共6页
Pd catalysts suffered from poor selectivity and stability for liquid-phase hydrogenation of maleic anhydride(MA) to gamma-butyrolactone(GBL).Thus,Pd/C catalysts modified with different Sn loadings were synthesized... Pd catalysts suffered from poor selectivity and stability for liquid-phase hydrogenation of maleic anhydride(MA) to gamma-butyrolactone(GBL).Thus,Pd/C catalysts modified with different Sn loadings were synthesized,and characterized by XRD,XPS,TEM and elemental mapping.The types of alloy phase and the amounts of the surface Pd-SnOx sites altered along with Sn/Pd mass ratios from 0-1.0synthesized in the process of preparation.The maximum reaction rate was 0.57 mol-GBL/(mol-Pd min)and selectivity was 95.94%when the Sn/Pd mass ratio was 0.6.It might be attributed to the formation of Pd2Sn alloy and less amounts of Pd-SnOx sites. 展开更多
关键词 Bimetallic catalysts Sn/Pd mass ratio Maleic anhydride Selective hydrogenation Gamma-butyrolactone
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