Dominant technology formation is the key for the hightech industry to“cross the chasm”and gain an established foothold in the market(and hence disrupt the regime).Therefore,a stimulus-response model is proposed to i...Dominant technology formation is the key for the hightech industry to“cross the chasm”and gain an established foothold in the market(and hence disrupt the regime).Therefore,a stimulus-response model is proposed to investigate the dominant technology by exploring its formation process and mechanism.Specifically,based on complex adaptive system theory and the basic stimulus-response model,we use a combination of agent-based modeling and system dynamics modeling to capture the interactions between dominant technology and the socio-technical landscape.The results indicate the following:(i)The dynamic interaction is“stimulus-reaction-selection”,which promotes the dominant technology’s formation.(ii)The dominant technology’s formation can be described as a dynamic process in which the adaptation intensity of technology standards increases continuously until it becomes the leading technology under the dual action of internal and external mechanisms.(iii)The dominant technology’s formation in the high-tech industry is influenced by learning ability,the number of adopting users and adaptability.Therein,a“critical scale”of learning ability exists to promote the formation of leading technology:a large number of adopting users can promote the dominant technology’s formation by influencing the adaptive response of technology standards to the socio-technical landscape and the choice of technology standards by the socio-technical landscape.There is a minimum threshold and a maximum threshold for the role of adaptability in the dominant technology’s formation.(iv)The socio-technical landscape can promote the leading technology’s shaping in the high-tech industry,and different elements have different effects.This study promotes research on the formation mechanism of dominant technology in the high-tech industry,presents new perspectives and methods for researchers,and provides essential enlightenment for managers to formulate technology strategies.展开更多
Nowadays,wireless communication devices turn out to be transportable owing to the execution of the current technologies.The antenna is the most important component deployed for communication purposes.The antenna plays...Nowadays,wireless communication devices turn out to be transportable owing to the execution of the current technologies.The antenna is the most important component deployed for communication purposes.The antenna plays an imperative role in receiving and transmitting the signals for any sensor network.Among varied antennas,micro strip fractal antenna(MFA)significantly contributes to increasing antenna gain.This study employs a hybrid optimization method known as the elephant clan updated grey wolf algorithm to introduce an optimized MFA design.This method optimizes antenna characteristics,including directivity and gain.Here,the factors,including length,width,ground plane length,height,and feed offset-X and feed offset-Y,are taken into account to achieve the best performance of gain and directivity.Ultimately,the superiority of the suggested technique over state-of-the-art strategies is calculated for various metrics such as cost and gain.The adopted model converges to a minimal value of 0.2872.Further,the spider monkey optimization(SMO)model accomplishes the worst performance over all other existing models like elephant herding optimization(EHO),grey wolf optimization(GWO),lion algorithm(LA),support vector regressor(SVR),bacterial foraging-particle swarm optimization(BF-PSO)and shark smell optimization(SSO).Effective MFA design is obtained using the suggested strategy regarding various parameters.展开更多
An improved social force model based on exit selection is proposed to simulate pedestrians' microscopic behaviors in subway station. The modification lies in considering three factors of spatial distance, occupant...An improved social force model based on exit selection is proposed to simulate pedestrians' microscopic behaviors in subway station. The modification lies in considering three factors of spatial distance, occupant density and exit width. In addition, the problem of pedestrians selecting exit frequently is solved as follows: not changing to other exits in the affected area of one exit, using the probability of remaining preceding exit and invoking function of exit selection after several simulation steps. Pedestrians in subway station have some special characteristics, such as explicit destinations, different familiarities with subway station. Finally, Beijing Zoo Subway Station is taken as an example and the feasibility of the model results is verified through the comparison of the actual data and simulation data. The simulation results show that the improved model can depict the microscopic behaviors of pedestrians in subway station.展开更多
A two phase model of rock was proposed in order to investigate the mechanism of brittle fracture due to uniaxial compression, in which rock was considered to be a composite material consisting of hard grains and collo...A two phase model of rock was proposed in order to investigate the mechanism of brittle fracture due to uniaxial compression, in which rock was considered to be a composite material consisting of hard grains and colloids. The stress state in colloid region near grains was calculated using Finite Element Method (FEM). The influence of the tensile stresses on the crack initiation and failure process of brittle rock subjected to uniaxial compression was investigated by numerical experiments. The FE results show that tensile stresses are induced easily in the neighboring area of hard grains with the maximum value near grain boundaries. The distribution of tensile stresses depends on the relative position of hard grains. The cracks initiated just near the boundary area of hard grains, which was governed by tensile stress. These results clearly reveal the micro fracture mechanism of brittle rock loaded by uniaxial compression. It can be concluded that the failure mode of brittle rock under uniaxial compression is still tensile fracture from the point view of microstructure. However, since the wide colloid region is still under compressive stress state, further propagation of boundary cracks through this region obviously needs more external load, thus causing the uniaxial compressive strength of rock much higher than its tensile strength obtained via Brazilian (splitting)展开更多
OBJECTIVES Parkinson disease(PD)is the second most common neurodegener⁃ative disease,but none of the current treatments for PD could halt the progress of the disease due to the limited understanding of the pathogenesi...OBJECTIVES Parkinson disease(PD)is the second most common neurodegener⁃ative disease,but none of the current treatments for PD could halt the progress of the disease due to the limited understanding of the pathogenesis.Increasing evidence proves that the close com⁃munication between the brain and the gastroin⁃testinal system is influenced by gut microbiota in PD pathogenesis,known as microbiota-gut-brain axis.However,the explicit mechanisms of micro⁃biota dysbiosis in PD development have not been well elucidated yet.FLZ,a novel squamosamide derivative,has been proved to be effective in many PD models and is undergoing the phaseⅠclinical trial to treat PD in China.The aims of our study are to assess the neuroprotective effects of FLZ treatment on PD and to further explore the underlying microbiota-related mechanisms of PD by using FLZ as a tool.METHODS Chronic administration of rotenone(30 mg·kg-1 per day)was utilized to induce a mouse model to mimic the pathological process of PD.Behavioral tests and gastrointestinal function tests were conduct⁃ed to evaluate the PD symptoms.Gut microbiota alterations were analyzed by 16s rRNA sequenc⁃ing.The intestinal permeability and blood-brain barrier structures were assessed by various methods.The pro-inflammatory cytokines and LPS levels in the colon,serum,and brain were detected by ELISA.Furthermore,the levels of in⁃flammation and TLR4/MyD88/NF-κB pathway in the substantia nigra(SN)and colon were mea⁃sured.RESULTS Behavioral tests and gastroin⁃testinal function tests found that rotenone-in⁃duced mice showed gastrointestinal dysfunctions(week 3)prior to the motor deficits(week 4).However,FLZ treatment significantly alleviated these PD symptoms.16S rRNA sequencing illus⁃trated that PD-related microbiota alterations in⁃duced by rotenone were reversed by FLZ treatment at various taxa levels.Especially,we identified an increased genus Akkermansia in the Rotenone group(P=0.0006),which could be reversed by FLZ administration(P=0.0070).By reducing microbiota dysbiosis,qPCR results showed that FLZ treatment suppressed intestinal inflammation of rotenone-challenged mice.After⁃wards,transmission electron microscopy(TEM),in vivo FITC permeability assay,bacterial translocation assay,and Western blotting togeth⁃er suggested that FLZ treatment attenuated the intestinal barrier destruction induced by rote⁃none.Subsequently,ELISA results showed that FLZ administration inhibited the leakage of pro-inflammatory cytokines(TNF-α,IL-1β,and IL-6)and LPS into the serum,suggesting the atten⁃uation of systemic inflammation.Then,several experiments including TEM analysis found that FLZ treatment restored blood-brain barrier struc⁃ture.Consequently,the immunofluorescence staining demonstrated that neuroinflammation(increased Iba-1+and GFAP+cells)and dopami⁃nergic neuronal death(reduced TH+cells)in the SN caused by rotenone were remarkably attenu⁃ated.Further mechanistic research proved that the anti-inflammatory effects of FLZ administra⁃tion were mediated through the TLR4/MyD88/NF-κB pathway both in the SN and colon.CONCLU⁃SION FLZ treatment ameliorates microbiota dys⁃biosis to protect the PD model via inhibiting TLR4 pathway,which contributes to one of the underlying mechanisms beneath its neuroprotec⁃tive effects.Our research also supports the importance of microbiota-gut-brain axis in PD pathogenesis,suggesting its potential role as a novel therapeutic target for PD treatment.展开更多
基金supported by the Shanghai Philosophy and Social Science Foundation(2022ECK004)Shanghai Soft Science Research Project(23692123400)。
文摘Dominant technology formation is the key for the hightech industry to“cross the chasm”and gain an established foothold in the market(and hence disrupt the regime).Therefore,a stimulus-response model is proposed to investigate the dominant technology by exploring its formation process and mechanism.Specifically,based on complex adaptive system theory and the basic stimulus-response model,we use a combination of agent-based modeling and system dynamics modeling to capture the interactions between dominant technology and the socio-technical landscape.The results indicate the following:(i)The dynamic interaction is“stimulus-reaction-selection”,which promotes the dominant technology’s formation.(ii)The dominant technology’s formation can be described as a dynamic process in which the adaptation intensity of technology standards increases continuously until it becomes the leading technology under the dual action of internal and external mechanisms.(iii)The dominant technology’s formation in the high-tech industry is influenced by learning ability,the number of adopting users and adaptability.Therein,a“critical scale”of learning ability exists to promote the formation of leading technology:a large number of adopting users can promote the dominant technology’s formation by influencing the adaptive response of technology standards to the socio-technical landscape and the choice of technology standards by the socio-technical landscape.There is a minimum threshold and a maximum threshold for the role of adaptability in the dominant technology’s formation.(iv)The socio-technical landscape can promote the leading technology’s shaping in the high-tech industry,and different elements have different effects.This study promotes research on the formation mechanism of dominant technology in the high-tech industry,presents new perspectives and methods for researchers,and provides essential enlightenment for managers to formulate technology strategies.
文摘Nowadays,wireless communication devices turn out to be transportable owing to the execution of the current technologies.The antenna is the most important component deployed for communication purposes.The antenna plays an imperative role in receiving and transmitting the signals for any sensor network.Among varied antennas,micro strip fractal antenna(MFA)significantly contributes to increasing antenna gain.This study employs a hybrid optimization method known as the elephant clan updated grey wolf algorithm to introduce an optimized MFA design.This method optimizes antenna characteristics,including directivity and gain.Here,the factors,including length,width,ground plane length,height,and feed offset-X and feed offset-Y,are taken into account to achieve the best performance of gain and directivity.Ultimately,the superiority of the suggested technique over state-of-the-art strategies is calculated for various metrics such as cost and gain.The adopted model converges to a minimal value of 0.2872.Further,the spider monkey optimization(SMO)model accomplishes the worst performance over all other existing models like elephant herding optimization(EHO),grey wolf optimization(GWO),lion algorithm(LA),support vector regressor(SVR),bacterial foraging-particle swarm optimization(BF-PSO)and shark smell optimization(SSO).Effective MFA design is obtained using the suggested strategy regarding various parameters.
基金Project(T14JB00200)supported by the Fundamental Research Funds for the Central UniversitiesChina+2 种基金Projects(RCS2012ZZ002RCS2012ZT003)supported by the State Key Laboratory of Rail Traffic Control and SafetyChina
文摘An improved social force model based on exit selection is proposed to simulate pedestrians' microscopic behaviors in subway station. The modification lies in considering three factors of spatial distance, occupant density and exit width. In addition, the problem of pedestrians selecting exit frequently is solved as follows: not changing to other exits in the affected area of one exit, using the probability of remaining preceding exit and invoking function of exit selection after several simulation steps. Pedestrians in subway station have some special characteristics, such as explicit destinations, different familiarities with subway station. Finally, Beijing Zoo Subway Station is taken as an example and the feasibility of the model results is verified through the comparison of the actual data and simulation data. The simulation results show that the improved model can depict the microscopic behaviors of pedestrians in subway station.
文摘A two phase model of rock was proposed in order to investigate the mechanism of brittle fracture due to uniaxial compression, in which rock was considered to be a composite material consisting of hard grains and colloids. The stress state in colloid region near grains was calculated using Finite Element Method (FEM). The influence of the tensile stresses on the crack initiation and failure process of brittle rock subjected to uniaxial compression was investigated by numerical experiments. The FE results show that tensile stresses are induced easily in the neighboring area of hard grains with the maximum value near grain boundaries. The distribution of tensile stresses depends on the relative position of hard grains. The cracks initiated just near the boundary area of hard grains, which was governed by tensile stress. These results clearly reveal the micro fracture mechanism of brittle rock loaded by uniaxial compression. It can be concluded that the failure mode of brittle rock under uniaxial compression is still tensile fracture from the point view of microstructure. However, since the wide colloid region is still under compressive stress state, further propagation of boundary cracks through this region obviously needs more external load, thus causing the uniaxial compressive strength of rock much higher than its tensile strength obtained via Brazilian (splitting)
文摘OBJECTIVES Parkinson disease(PD)is the second most common neurodegener⁃ative disease,but none of the current treatments for PD could halt the progress of the disease due to the limited understanding of the pathogenesis.Increasing evidence proves that the close com⁃munication between the brain and the gastroin⁃testinal system is influenced by gut microbiota in PD pathogenesis,known as microbiota-gut-brain axis.However,the explicit mechanisms of micro⁃biota dysbiosis in PD development have not been well elucidated yet.FLZ,a novel squamosamide derivative,has been proved to be effective in many PD models and is undergoing the phaseⅠclinical trial to treat PD in China.The aims of our study are to assess the neuroprotective effects of FLZ treatment on PD and to further explore the underlying microbiota-related mechanisms of PD by using FLZ as a tool.METHODS Chronic administration of rotenone(30 mg·kg-1 per day)was utilized to induce a mouse model to mimic the pathological process of PD.Behavioral tests and gastrointestinal function tests were conduct⁃ed to evaluate the PD symptoms.Gut microbiota alterations were analyzed by 16s rRNA sequenc⁃ing.The intestinal permeability and blood-brain barrier structures were assessed by various methods.The pro-inflammatory cytokines and LPS levels in the colon,serum,and brain were detected by ELISA.Furthermore,the levels of in⁃flammation and TLR4/MyD88/NF-κB pathway in the substantia nigra(SN)and colon were mea⁃sured.RESULTS Behavioral tests and gastroin⁃testinal function tests found that rotenone-in⁃duced mice showed gastrointestinal dysfunctions(week 3)prior to the motor deficits(week 4).However,FLZ treatment significantly alleviated these PD symptoms.16S rRNA sequencing illus⁃trated that PD-related microbiota alterations in⁃duced by rotenone were reversed by FLZ treatment at various taxa levels.Especially,we identified an increased genus Akkermansia in the Rotenone group(P=0.0006),which could be reversed by FLZ administration(P=0.0070).By reducing microbiota dysbiosis,qPCR results showed that FLZ treatment suppressed intestinal inflammation of rotenone-challenged mice.After⁃wards,transmission electron microscopy(TEM),in vivo FITC permeability assay,bacterial translocation assay,and Western blotting togeth⁃er suggested that FLZ treatment attenuated the intestinal barrier destruction induced by rote⁃none.Subsequently,ELISA results showed that FLZ administration inhibited the leakage of pro-inflammatory cytokines(TNF-α,IL-1β,and IL-6)and LPS into the serum,suggesting the atten⁃uation of systemic inflammation.Then,several experiments including TEM analysis found that FLZ treatment restored blood-brain barrier struc⁃ture.Consequently,the immunofluorescence staining demonstrated that neuroinflammation(increased Iba-1+and GFAP+cells)and dopami⁃nergic neuronal death(reduced TH+cells)in the SN caused by rotenone were remarkably attenu⁃ated.Further mechanistic research proved that the anti-inflammatory effects of FLZ administra⁃tion were mediated through the TLR4/MyD88/NF-κB pathway both in the SN and colon.CONCLU⁃SION FLZ treatment ameliorates microbiota dys⁃biosis to protect the PD model via inhibiting TLR4 pathway,which contributes to one of the underlying mechanisms beneath its neuroprotec⁃tive effects.Our research also supports the importance of microbiota-gut-brain axis in PD pathogenesis,suggesting its potential role as a novel therapeutic target for PD treatment.
