Wireless sensor networks(WSNs)are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and den...Wireless sensor networks(WSNs)are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service(DoS)-resistant user authentication scheme for two-tiered WSNs.The proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash function.This feature is more suitable for the resource-limited sensor nodes and mobile devices.And it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user list.In addition,pseudonym identity is introduced to preserve user anonymity.Through clever design,our proposed scheme can prevent smart card breaches.Finally,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.展开更多
The two-tier shareholding structure,which originated in the United States,has become popular around the world.Unlike the traditional model of“equal shares with equal rights”,the core feature of the two-tier sharehol...The two-tier shareholding structure,which originated in the United States,has become popular around the world.Unlike the traditional model of“equal shares with equal rights”,the core feature of the two-tier shareholding structure is that the company issues two classes of shares with different voting rights.It enables the concentration and stabilization of corporate control,which has a positive effect on the long-term development of the company and resistance to hostile takeovers.Against the background of the rapid development of the capital market and the continuous innovation of corporate governance structure,the two-tier shareholding structure has begun to be adopted by many enterprises.While this structure can improve the efficiency of corporate governance and promote corporate growth,it also raises a number of challenges.In particular,for small and medium-sized shareholders,their shareholdings may face the problem of limited or no voting rights,as well as the lack of an effective internal and external monitoring mechanism for the company.These issues may lead to the impairment of the rights of small and medium-sized shareholders.Currently,challenges in practice include inadequate laws and regulations,insufficient disclosure of information,and inadequate monitoring mechanisms.Therefore,exploring the path to protect the rights and interests of small and medium-sized shareholders and analyzing their current situation has become an important area in the study of two-tier shareholding structures.This paper starts from the actual situation,analyzes the problems exposed in the operation process of two-tier shareholding structure,and then explores the practical and feasible methods to protect the rights and interests of small and medium-sized shareholders on this basis,with a view to putting forward valuable references for the development of China’s securities market.展开更多
This paper proposed a two-tier location management mechanism （TTLM） by improving the current registration mechanism （CR） in IP Multimedia Subsystem （IMS）. The TTLM includes the visited network registration and t...This paper proposed a two-tier location management mechanism （TTLM） by improving the current registration mechanism （CR） in IP Multimedia Subsystem （IMS）. The TTLM includes the visited network registration and the home network registration, in which the visited network registration is responsible for re-registration in IMS. When subscriber roams, the location information of home network will be updated by the visited network based on the change of user equipment （UE）＇ s IP address. Thereibre the TTLM can reduce the times of IMS registration signaling. Using the proposed analytical model, the performance of the CR and the proposed TTLM were investigated. After the performance analysis of CR and TTLM by using proposed analytical model, the cost of CR in IMS could significantly be reduced theoretically and also was proven by simulation experiments.展开更多
Because of its paramount importance in the successful industrial control strategy of a given heat exchanger network(HEN),the control structure designs for providing appropriate manipulated variable(MV)and controlled v...Because of its paramount importance in the successful industrial control strategy of a given heat exchanger network(HEN),the control structure designs for providing appropriate manipulated variable(MV)and controlled variable pairings have received considerable attention.However,quite frequently HENs with such control structures face the problem of hard constraints,typically holding the HENs at less controlled operating space.So both the MV pairings and the above control pairings should be considered to design a control structure.This paper investigates the systematic incorporation of the two pairings,and presents a methodology for designing such two-tier control structure.This is developed based on the sequential strategy,coupling an indirect-tier with direct-tier control structure design,wherein the intention is realized in the former stage and the latter is implemented for further optimization.The MV identification and pairing are achieved through variations in heat load of heat exchangers to design the indirect-tier control structure.Then the direct-tier control structure is followed the relative gain array pairing rules.With the proposed methodology,on the one hand,it generates an explicit connection between the MV pairings and the HEN configuration,and the quantitative interaction measure is improved to avoid the multiple solutions to break the relationship among all the control pairings into individuals;on the other hand,a two-tier control structure reveals control potentials and control system design requirements,this may avoid complex and economically unfavourable control and HEN structures.The application of proposed framework is illustrated with two cases involving the dynamic simulation analysis,the quantitative assessment and the random test.展开更多
This paper studies an interference coordination method by means of spectrum allocation in Long-Term Evolution (LTE) multi-cell scenario that comprises of macrocells and femtocells. The purpose is to maximize the total...This paper studies an interference coordination method by means of spectrum allocation in Long-Term Evolution (LTE) multi-cell scenario that comprises of macrocells and femtocells. The purpose is to maximize the total throughput of femtocells while ensuring the Signal-to-Interference plus Noise Ratio (SINR) of the edge macro mobile stations (mMSs) and the edge femtocell Mobile Stations (fMSs). A new spectrum allocation algorithm based on graph theory is proposed to reduce the interference. Firstly, the ratio of Resource Blocks (RBs) that mMSs occupy is obtained by genetic algorithm. Then, after considering the impact of the macro Base Stations (mBSs) and small scale fading to the fMS on different RBs, multi-interference graphs are established and the spectrum is allocated dynamically. The simulation results show that the proposed algorithm can meet the Quality of Service (QoS) requirements of the mMSs. It can strike a balance between the edge fMSs' throughput and the whole fMSs' throughput.展开更多
This paper proposes a novel optimization scheme to support stable and reliable vehicle-to-everything connections in two-tier networks,where the uplink channel of the cellular user is reused by underlay vehicle-to-vehi...This paper proposes a novel optimization scheme to support stable and reliable vehicle-to-everything connections in two-tier networks,where the uplink channel of the cellular user is reused by underlay vehicle-to-vehicle communications.However,considering complex channel fading and high-speed vehicle movement,the cer-tainty assumption is impractical and fails to maintain power control strategy in reality in the traditional statical vehicular networks.Rather than the perfect channel state information assumption,the first-order Gauss-Markov process which is a probabilistic model affected by vehicle speed and fading is introduced to describe imperfect channel gains.Moreover,interference management is a major challenge in reusing communications,especially in uncertain channel environments.Power control is an effective way to realize interference management,and optimal power allocation can ensure that interference of the user meets the communication requirements.In this study,the sum-rate-oriented power control scheme and minimum-rate-oriented power control scheme were implemented to manage interference and satisfy different design objectives.Since both of these schemes are non-convex and intractable,the Bernstein approximation and successive convex approximation methods were adopted to transform the original problems into convex ones.Furthermore,a novel distributed robust power control al-gorithm was developed to determine the optimal solutions.The performance of the algorithm was evaluated through numerical simulations,and the results indicate that the proposed algorithm is effective in vehicular communication networks with uncertain channel environments.展开更多
There has been an exponential rise in mobile data traffic in recent times due to the increasing popularity of portable devices like tablets,smartphones,and laptops.The rapid rise in the use of these portable devices h...There has been an exponential rise in mobile data traffic in recent times due to the increasing popularity of portable devices like tablets,smartphones,and laptops.The rapid rise in the use of these portable devices has put extreme stress on the network service providers while forcing telecommunication engineers to look for innovative solutions to meet the increased demand.One solution to the problem is the emergence of fifth-generation(5G)wireless communication,which can address the challenges by offering very broad wireless area capacity and potential cut-power consumption.The application of small cells is the fundamental mechanism for the 5Gtechnology.The use of small cells can enhance the facility for higher capacity and reuse.However,it must be noted that small cells deployment will lead to frequent handovers of mobile nodes.Considering the importance of small cells in 5G,this paper aims to examine a new resource management scheme that can work to minimize the rate of handovers formobile phones through careful resources allocation in a two-tier network.Therefore,the resource management problem has been formulated as an optimization issue thatwe aim to overcome through an optimal solution.To find a solution to the existing problem of frequent handovers,a heuristic approach has been used.This solution is then evaluated and validated through simulation and testing,during which the performance was noted to improve by 12%in the context of handover costs.Therefore,this model has been observed to be more efficient as compared to the existing model.展开更多
The goal of the study was the development of a system to monitor the members of supervisory and management boards. The system currently covers 8,454 joint stock companies registered in Poland. The main purpose of the ...The goal of the study was the development of a system to monitor the members of supervisory and management boards. The system currently covers 8,454 joint stock companies registered in Poland. The main purpose of the system is to monitor every change in the composition of every board of every joint stock company, from March 2001 up to the present, and it is updated every month. This system, however, also enables us to confirm some of the theories from the field of corporate governance. A generation change has been identified in the boards of the joint stock companies which were examined. Women constitute a large, and continuously increasing, section of the board members. The number of family companies, and of family involvement in boards, is still increasing. Board members of financial institutions （and not just of banks） possess significantly more directorates than board members of non-financial institutions. The number of interlocking directorates is positively linked to the macroeconomic development indicator of the total investment as percentage of GDP for Poland.展开更多
In order to overcome the shortcomings brought up by the single-layer agency relation analyses of agency problems within enterprise group, two-tiered agency models in the internal capital market are set up, and how ren...In order to overcome the shortcomings brought up by the single-layer agency relation analyses of agency problems within enterprise group, two-tiered agency models in the internal capital market are set up, and how rent-seeking behaviors of member firms＇ managers affect investment allocation decision made by headquarters manager is demonstrated. From equilibrium solutions of the model, it＇s inferred that the larger the divergence of member firm＇s productivity is, the higher probability of investment allocation distortion is.展开更多
Objective:To investigate the value of serum human epididymis protein 4(HE4) in differential diagnosis of patients with low-grade serous(LGSC) and high-grade serous carcinoma(HGSC) serous ovarian cancer.Methods:LGSC an...Objective:To investigate the value of serum human epididymis protein 4(HE4) in differential diagnosis of patients with low-grade serous(LGSC) and high-grade serous carcinoma(HGSC) serous ovarian cancer.Methods:LGSC and HGSC serous ovarian cancer were diagnosed by the two-tier grade system,serum levels of HE4 and carbohydrate antigen 12S(CA125) were measured by ELBA and radioisotope method,respectively in 60 serous ovarian cancer patients. HE4 and TPS3 protein in cancer tissue were measured by immunohistochemical method. Results:The difference in density of HE4 and TP53 protein was significant between LGSC and HGSC tissue,while serum CA12S did not show significant difference between different serum samples.There was significant difference in serum HE4 levels between LGSC and HGSC and the result was different within FIGO(Ⅰ+Ⅱ) stage,suggesting HE4 was not a reliable biomarker for the discrimination between LGSC and HCSC.HE4 had potential as a biomarker for the discrimination between LGSC and HGSC but the role in early diagnosis was limited.Conclusions:HE4 may be a reliable marker for differential diagnosis of LGSC and HGSC.But its role in early diagnosis of LGSC and HGSC need to be confirmed from the perspective of two-tier grade system.展开更多
WSN has been developing from traditional environment monitoring applications to the ubiquitous information services such as the Congestion-oriented Intelligent Transportation System （ColTS）. However, the mobility of...WSN has been developing from traditional environment monitoring applications to the ubiquitous information services such as the Congestion-oriented Intelligent Transportation System （ColTS）. However, the mobility of nodes makes data dissemination a hard nut to crack. In this paper, we propose MSDD, a multiple mobile sinks data dissemination mechanism for solving the dissemination problem. The main ideas of MSDD are constructing a two-tier grid structure by a designated sink, exploiting a hierarchical monitoring mechanism, and employing a global agent to track the sink locations in order to make the emergencies reported to the sinks immediately, In addition, MSDD supports the query-driven data dissemination. Being compared with TTDD, MSDD is theoretically proved to have less communication overhead. We also validate MSDD outperforms TTDD in reliability and the emergency delivery latency bv simulations.展开更多
Based on the micro individual data from China Health and Nutrition Survey (CHNS) database and the development of China’s medical and health system reform since the reform and opening-up in 1978, this paper applies a ...Based on the micro individual data from China Health and Nutrition Survey (CHNS) database and the development of China’s medical and health system reform since the reform and opening-up in 1978, this paper applies a two-tier stochastic frontier model to measure the degree of asymmetric information between physicians and patients in China’s medical service market and estimate the impact of bargaining on the final price of health care both holistically and annually. The empirical results show that: 1) The information mastered by physicians and patients have significant but opposing effects on the final medical service price. Physicians hold more information relative to patients and thus have stronger bargaining power. 2) Almost all patients will be forced to accept a medical price higher than the benchmark price by 16.52% on average by receiving excessive and expensive medical services, despite the differences in bargaining power between physicians and patients are highly heterogeneous. 3) The series of medical reforms in China had different impacts on medical care pricing efficiency. Especially, the early medical reforms could impose a positive impact on the efficiency of the medical market in the initial stage. I further propose that the path choice of China’s new round of medical reform should be as follows: It is necessary to insist on government-led efforts to protect the public welfare of medical services, and to introduce market mechanisms to mobilize social resources and improve the efficiency of the medical market. In addition, I point out that the establishment and improvement of the general practitioner system may reduce the degree of information asymmetry between physicians and patients, thus alleviating China's deteriorating physician-patient relationship.展开更多
Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect inf...Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect influence exporting firms' markup. Our findings suggest that the interaction between selection effect and competition effect ultimately causes actual firm markup to be higher than the baseline markup by 7.11%. Exporting firms' actual markup is higher than the baseline markup by different degrees. In terms of the decomposition of selection effect, TFP explains for 28.05% of selection effect, and nonproductivity factors explain for the rest 71.95%. By controlling for the type of firms' export,the export-productivity paradox only exists for processing trade firms, which shows that with increasing trade facilitation, the policy incentives to encourage firms to export are major contributors to the low export markups.展开更多
As the international environment changes,frequent geopolitical crises continue to hinder the healthy development of global stock markets.To analyze in-depth the risk contagion path between the international stock mark...As the international environment changes,frequent geopolitical crises continue to hinder the healthy development of global stock markets.To analyze in-depth the risk contagion path between the international stock market and geopolitics under the impact of extreme events,this paper explores the tail risk interactive contagion mechanism and dynamic effects of the double-layer network between the international stock market and geopolitics from the perspective of complex networks.Empirical research finds that geopolitical conflicts exacerbate risk contagion among international stock markets,and there are significant differences in risk contagion between developed and emerging economies.The analysis of the complex interaction effect in the doublelayer network of the international stock market and geopolitics shows that the intralayer risk spillover effect of geopolitics in the short term is significantly higher than that of the stock price volatility network layer.Finally,the study on the dynamic changes of the double-layer network connectedness between the international stock market and geopolitics found that the shock of extreme events,such as military conflict and public health security,is an important factor in triggering the cross-contagion of risks.The research conclusions provide new ideas for preventing the cross-contagion of geopolitical risks in the stock markets of various countries under the evolution of the global political and economic pattern.展开更多
Healthcare downstream referral programs,where patients are transferred to a community hospital after surgical treatment in a tertiary hospital for rehabilitation treatment,have been widely advocated.However,no appropr...Healthcare downstream referral programs,where patients are transferred to a community hospital after surgical treatment in a tertiary hospital for rehabilitation treatment,have been widely advocated.However,no appropriate payment scheme aligns incentives to promote the program.This paper mainly compares two payment schemes:bundled and unbundled,which refer to packaged versus separate payments for surgery and rehabilitation treatment.By establishing a three-stage Stackelberg game within a M/Cox-2/1 queuing framework,our paper considers a payer maximizing social welfare in the base model and a payer maximizing the system's long-term surplus in the extension.The base model finds that:(i)the payer pays less under the bundled payment scheme when the potential arrival rate is low and the delay cost is high;otherwise,in most cases,the payer pays more under the bundled payment scheme.(ii)The bundled payment scheme yields greater referral volume and a higher level of effort.(iii)The bundled payment scheme is a weak Pareto improvement(PI hereafter)when both the potential arrival rate and the delay cost are high;the unbundled payment scheme is a PI when the delay cost is moderate and the potential arrival rate is relatively low;otherwise,there is no PI.However,when the payer aims to maximize the system's long-term surplus with a limited budget,several different results are obtained.These results can provide practical insights for policymakers to coordinate downstream referral programs.展开更多
This paper focuses on an outpatient capacity allocation problem where the patient demand is quite higher than the supply. We study an adding capacity policy to mitigate the mismatch between supply and demand. Under th...This paper focuses on an outpatient capacity allocation problem where the patient demand is quite higher than the supply. We study an adding capacity policy to mitigate the mismatch between supply and demand. Under this policy, the doctor is allowed to add capacity if all regular capacity have been booked. A capacity allocation model is formulated for both possible no-show routine patients and all show-up same-day patients. The purpose is to determine the number of capacity can be added and how to allocate regular capacity among routine patients and same-day patients, towards maximizing the expected profit, which is composed of the expected income minus the cost of weighted expected doctor＇s overload work caused by the adding capacity policy and the cost of rejecting patients. To achieve the aims, we prove the expected profit monotonously decreases when the number of additional capacity exceeds a threshold, and present a two-tier enumeration search algorithm to fred the global optimal solution based on the proof. Numerical results indicate that the proposed policy performs well under different levels of demand higher than supply. The optimal number of the additional capacity is hardly affected by varying total expected patient demand. Additionally, under the change of no-show rate, the number of regular capacity allocated to routine patients becomes more stable, compared with the optimal scheme without considering adding capacity policy.展开更多
文摘Wireless sensor networks(WSNs)are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service(DoS)-resistant user authentication scheme for two-tiered WSNs.The proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash function.This feature is more suitable for the resource-limited sensor nodes and mobile devices.And it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user list.In addition,pseudonym identity is introduced to preserve user anonymity.Through clever design,our proposed scheme can prevent smart card breaches.Finally,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.
文摘The two-tier shareholding structure,which originated in the United States,has become popular around the world.Unlike the traditional model of“equal shares with equal rights”,the core feature of the two-tier shareholding structure is that the company issues two classes of shares with different voting rights.It enables the concentration and stabilization of corporate control,which has a positive effect on the long-term development of the company and resistance to hostile takeovers.Against the background of the rapid development of the capital market and the continuous innovation of corporate governance structure,the two-tier shareholding structure has begun to be adopted by many enterprises.While this structure can improve the efficiency of corporate governance and promote corporate growth,it also raises a number of challenges.In particular,for small and medium-sized shareholders,their shareholdings may face the problem of limited or no voting rights,as well as the lack of an effective internal and external monitoring mechanism for the company.These issues may lead to the impairment of the rights of small and medium-sized shareholders.Currently,challenges in practice include inadequate laws and regulations,insufficient disclosure of information,and inadequate monitoring mechanisms.Therefore,exploring the path to protect the rights and interests of small and medium-sized shareholders and analyzing their current situation has become an important area in the study of two-tier shareholding structures.This paper starts from the actual situation,analyzes the problems exposed in the operation process of two-tier shareholding structure,and then explores the practical and feasible methods to protect the rights and interests of small and medium-sized shareholders on this basis,with a view to putting forward valuable references for the development of China’s securities market.
基金Supported by National Science Fund for Distinguished Young Scholars (No. 60525110 )National Basic Research Program of China (No.2007CB307100, 2007CB307103)+1 种基金Program for New Century Excellent Talents in University (No. NCET-04-0111 )Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘This paper proposed a two-tier location management mechanism （TTLM） by improving the current registration mechanism （CR） in IP Multimedia Subsystem （IMS）. The TTLM includes the visited network registration and the home network registration, in which the visited network registration is responsible for re-registration in IMS. When subscriber roams, the location information of home network will be updated by the visited network based on the change of user equipment （UE）＇ s IP address. Thereibre the TTLM can reduce the times of IMS registration signaling. Using the proposed analytical model, the performance of the CR and the proposed TTLM were investigated. After the performance analysis of CR and TTLM by using proposed analytical model, the cost of CR in IMS could significantly be reduced theoretically and also was proven by simulation experiments.
基金financial support from Jiangsu Collaborative Innovation Center for Cultural Creativity (XYN1911)the National Natural Science Foundation of China (22008023+1 种基金21776035)Natural Science Foundation of Jiangsu Education Department (20KJB510041)
文摘Because of its paramount importance in the successful industrial control strategy of a given heat exchanger network(HEN),the control structure designs for providing appropriate manipulated variable(MV)and controlled variable pairings have received considerable attention.However,quite frequently HENs with such control structures face the problem of hard constraints,typically holding the HENs at less controlled operating space.So both the MV pairings and the above control pairings should be considered to design a control structure.This paper investigates the systematic incorporation of the two pairings,and presents a methodology for designing such two-tier control structure.This is developed based on the sequential strategy,coupling an indirect-tier with direct-tier control structure design,wherein the intention is realized in the former stage and the latter is implemented for further optimization.The MV identification and pairing are achieved through variations in heat load of heat exchangers to design the indirect-tier control structure.Then the direct-tier control structure is followed the relative gain array pairing rules.With the proposed methodology,on the one hand,it generates an explicit connection between the MV pairings and the HEN configuration,and the quantitative interaction measure is improved to avoid the multiple solutions to break the relationship among all the control pairings into individuals;on the other hand,a two-tier control structure reveals control potentials and control system design requirements,this may avoid complex and economically unfavourable control and HEN structures.The application of proposed framework is illustrated with two cases involving the dynamic simulation analysis,the quantitative assessment and the random test.
基金Supported by National Natural Science Foundation of China (61171094, 61071092)National Science & Technology Key Project (2011ZX03001-006-02, 2011ZX03005-004-03)Key Project of Jiangsu Provincial Natural Science Foundation (BK2011027)
文摘This paper studies an interference coordination method by means of spectrum allocation in Long-Term Evolution (LTE) multi-cell scenario that comprises of macrocells and femtocells. The purpose is to maximize the total throughput of femtocells while ensuring the Signal-to-Interference plus Noise Ratio (SINR) of the edge macro mobile stations (mMSs) and the edge femtocell Mobile Stations (fMSs). A new spectrum allocation algorithm based on graph theory is proposed to reduce the interference. Firstly, the ratio of Resource Blocks (RBs) that mMSs occupy is obtained by genetic algorithm. Then, after considering the impact of the macro Base Stations (mBSs) and small scale fading to the fMS on different RBs, multi-interference graphs are established and the spectrum is allocated dynamically. The simulation results show that the proposed algorithm can meet the Quality of Service (QoS) requirements of the mMSs. It can strike a balance between the edge fMSs' throughput and the whole fMSs' throughput.
基金supported by National Natural Science Foundation of China under grant 61873223,61803328the Natural Science Foundation of Hebei Province under grant F2019203095Beijing Natural Science Foundation under grant L201002.
文摘This paper proposes a novel optimization scheme to support stable and reliable vehicle-to-everything connections in two-tier networks,where the uplink channel of the cellular user is reused by underlay vehicle-to-vehicle communications.However,considering complex channel fading and high-speed vehicle movement,the cer-tainty assumption is impractical and fails to maintain power control strategy in reality in the traditional statical vehicular networks.Rather than the perfect channel state information assumption,the first-order Gauss-Markov process which is a probabilistic model affected by vehicle speed and fading is introduced to describe imperfect channel gains.Moreover,interference management is a major challenge in reusing communications,especially in uncertain channel environments.Power control is an effective way to realize interference management,and optimal power allocation can ensure that interference of the user meets the communication requirements.In this study,the sum-rate-oriented power control scheme and minimum-rate-oriented power control scheme were implemented to manage interference and satisfy different design objectives.Since both of these schemes are non-convex and intractable,the Bernstein approximation and successive convex approximation methods were adopted to transform the original problems into convex ones.Furthermore,a novel distributed robust power control al-gorithm was developed to determine the optimal solutions.The performance of the algorithm was evaluated through numerical simulations,and the results indicate that the proposed algorithm is effective in vehicular communication networks with uncertain channel environments.
基金This work was supported by the Taif University Researchers Supporting Project number(TURSP-2020/79),Taif University,Taif,Saudi Arabia.
文摘There has been an exponential rise in mobile data traffic in recent times due to the increasing popularity of portable devices like tablets,smartphones,and laptops.The rapid rise in the use of these portable devices has put extreme stress on the network service providers while forcing telecommunication engineers to look for innovative solutions to meet the increased demand.One solution to the problem is the emergence of fifth-generation(5G)wireless communication,which can address the challenges by offering very broad wireless area capacity and potential cut-power consumption.The application of small cells is the fundamental mechanism for the 5Gtechnology.The use of small cells can enhance the facility for higher capacity and reuse.However,it must be noted that small cells deployment will lead to frequent handovers of mobile nodes.Considering the importance of small cells in 5G,this paper aims to examine a new resource management scheme that can work to minimize the rate of handovers formobile phones through careful resources allocation in a two-tier network.Therefore,the resource management problem has been formulated as an optimization issue thatwe aim to overcome through an optimal solution.To find a solution to the existing problem of frequent handovers,a heuristic approach has been used.This solution is then evaluated and validated through simulation and testing,during which the performance was noted to improve by 12%in the context of handover costs.Therefore,this model has been observed to be more efficient as compared to the existing model.
文摘The goal of the study was the development of a system to monitor the members of supervisory and management boards. The system currently covers 8,454 joint stock companies registered in Poland. The main purpose of the system is to monitor every change in the composition of every board of every joint stock company, from March 2001 up to the present, and it is updated every month. This system, however, also enables us to confirm some of the theories from the field of corporate governance. A generation change has been identified in the boards of the joint stock companies which were examined. Women constitute a large, and continuously increasing, section of the board members. The number of family companies, and of family involvement in boards, is still increasing. Board members of financial institutions （and not just of banks） possess significantly more directorates than board members of non-financial institutions. The number of interlocking directorates is positively linked to the macroeconomic development indicator of the total investment as percentage of GDP for Poland.
文摘In order to overcome the shortcomings brought up by the single-layer agency relation analyses of agency problems within enterprise group, two-tiered agency models in the internal capital market are set up, and how rent-seeking behaviors of member firms＇ managers affect investment allocation decision made by headquarters manager is demonstrated. From equilibrium solutions of the model, it＇s inferred that the larger the divergence of member firm＇s productivity is, the higher probability of investment allocation distortion is.
基金suuported by Young Researcher Foundation from Education Department of Jiangxi Province(Grand No.GJJ12161)
文摘Objective:To investigate the value of serum human epididymis protein 4(HE4) in differential diagnosis of patients with low-grade serous(LGSC) and high-grade serous carcinoma(HGSC) serous ovarian cancer.Methods:LGSC and HGSC serous ovarian cancer were diagnosed by the two-tier grade system,serum levels of HE4 and carbohydrate antigen 12S(CA125) were measured by ELBA and radioisotope method,respectively in 60 serous ovarian cancer patients. HE4 and TPS3 protein in cancer tissue were measured by immunohistochemical method. Results:The difference in density of HE4 and TP53 protein was significant between LGSC and HGSC tissue,while serum CA12S did not show significant difference between different serum samples.There was significant difference in serum HE4 levels between LGSC and HGSC and the result was different within FIGO(Ⅰ+Ⅱ) stage,suggesting HE4 was not a reliable biomarker for the discrimination between LGSC and HCSC.HE4 had potential as a biomarker for the discrimination between LGSC and HGSC but the role in early diagnosis was limited.Conclusions:HE4 may be a reliable marker for differential diagnosis of LGSC and HGSC.But its role in early diagnosis of LGSC and HGSC need to be confirmed from the perspective of two-tier grade system.
基金This work was supported in part by China National Natural Science Foundation under Grant 61271185,and the Fundamental Research Funds for the Central Universities
文摘WSN has been developing from traditional environment monitoring applications to the ubiquitous information services such as the Congestion-oriented Intelligent Transportation System （ColTS）. However, the mobility of nodes makes data dissemination a hard nut to crack. In this paper, we propose MSDD, a multiple mobile sinks data dissemination mechanism for solving the dissemination problem. The main ideas of MSDD are constructing a two-tier grid structure by a designated sink, exploiting a hierarchical monitoring mechanism, and employing a global agent to track the sink locations in order to make the emergencies reported to the sinks immediately, In addition, MSDD supports the query-driven data dissemination. Being compared with TTDD, MSDD is theoretically proved to have less communication overhead. We also validate MSDD outperforms TTDD in reliability and the emergency delivery latency bv simulations.
文摘Based on the micro individual data from China Health and Nutrition Survey (CHNS) database and the development of China’s medical and health system reform since the reform and opening-up in 1978, this paper applies a two-tier stochastic frontier model to measure the degree of asymmetric information between physicians and patients in China’s medical service market and estimate the impact of bargaining on the final price of health care both holistically and annually. The empirical results show that: 1) The information mastered by physicians and patients have significant but opposing effects on the final medical service price. Physicians hold more information relative to patients and thus have stronger bargaining power. 2) Almost all patients will be forced to accept a medical price higher than the benchmark price by 16.52% on average by receiving excessive and expensive medical services, despite the differences in bargaining power between physicians and patients are highly heterogeneous. 3) The series of medical reforms in China had different impacts on medical care pricing efficiency. Especially, the early medical reforms could impose a positive impact on the efficiency of the medical market in the initial stage. I further propose that the path choice of China’s new round of medical reform should be as follows: It is necessary to insist on government-led efforts to protect the public welfare of medical services, and to introduce market mechanisms to mobilize social resources and improve the efficiency of the medical market. In addition, I point out that the establishment and improvement of the general practitioner system may reduce the degree of information asymmetry between physicians and patients, thus alleviating China's deteriorating physician-patient relationship.
基金Sponsorship of the National Social Science Foundation (NSSF) Youth Project (16CJL014)the China Postdoctoral Science Special Foundation (2017T100001)
文摘Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect influence exporting firms' markup. Our findings suggest that the interaction between selection effect and competition effect ultimately causes actual firm markup to be higher than the baseline markup by 7.11%. Exporting firms' actual markup is higher than the baseline markup by different degrees. In terms of the decomposition of selection effect, TFP explains for 28.05% of selection effect, and nonproductivity factors explain for the rest 71.95%. By controlling for the type of firms' export,the export-productivity paradox only exists for processing trade firms, which shows that with increasing trade facilitation, the policy incentives to encourage firms to export are major contributors to the low export markups.
基金supported by the National Natural Science Foundation of China(Nos.72271135,72141304,71901130)National Social Science Fund of China(22&ZD117)+3 种基金Laboratory of Computation and Analyticsof Complex Management Systems(Tianjin University)Special Funds for Taishan Scholars(tsqn202211120)2024 QingdaoFinance Society Key Project2024 Qingdao Social Science Planning Project.
文摘As the international environment changes,frequent geopolitical crises continue to hinder the healthy development of global stock markets.To analyze in-depth the risk contagion path between the international stock market and geopolitics under the impact of extreme events,this paper explores the tail risk interactive contagion mechanism and dynamic effects of the double-layer network between the international stock market and geopolitics from the perspective of complex networks.Empirical research finds that geopolitical conflicts exacerbate risk contagion among international stock markets,and there are significant differences in risk contagion between developed and emerging economies.The analysis of the complex interaction effect in the doublelayer network of the international stock market and geopolitics shows that the intralayer risk spillover effect of geopolitics in the short term is significantly higher than that of the stock price volatility network layer.Finally,the study on the dynamic changes of the double-layer network connectedness between the international stock market and geopolitics found that the shock of extreme events,such as military conflict and public health security,is an important factor in triggering the cross-contagion of risks.The research conclusions provide new ideas for preventing the cross-contagion of geopolitical risks in the stock markets of various countries under the evolution of the global political and economic pattern.
基金the following financial support for the research,authorship,and/or publication of this article:Wenhui Zhou and Yanhong Gan was supported by the National Science Foundation of China,Grant/Award Numbers:71925002the Foundation for Innovative Research Groups of the National Natural Science Foundation of China,Grant/Award Numbers:72321001+3 种基金Yuanyuan Dang was supported by the National Natural Science Foundation of China,Grant/Award Numbers:72471095 and 72101090the Special Fund Project for Scientific and Technological Innovation(Soft Science)of Guangdong Province,Grant/Award Numbers:2022A1515011620 and 2024A1515011518Guangdong Philosophy and Social Sciences,Grant/Award Numbers:GD21YGL09 and 2023GZYB22Innovative Research Team of Shanghai International Studies University,Grant/Award Numbers:2023KFKT003.
文摘Healthcare downstream referral programs,where patients are transferred to a community hospital after surgical treatment in a tertiary hospital for rehabilitation treatment,have been widely advocated.However,no appropriate payment scheme aligns incentives to promote the program.This paper mainly compares two payment schemes:bundled and unbundled,which refer to packaged versus separate payments for surgery and rehabilitation treatment.By establishing a three-stage Stackelberg game within a M/Cox-2/1 queuing framework,our paper considers a payer maximizing social welfare in the base model and a payer maximizing the system's long-term surplus in the extension.The base model finds that:(i)the payer pays less under the bundled payment scheme when the potential arrival rate is low and the delay cost is high;otherwise,in most cases,the payer pays more under the bundled payment scheme.(ii)The bundled payment scheme yields greater referral volume and a higher level of effort.(iii)The bundled payment scheme is a weak Pareto improvement(PI hereafter)when both the potential arrival rate and the delay cost are high;the unbundled payment scheme is a PI when the delay cost is moderate and the potential arrival rate is relatively low;otherwise,there is no PI.However,when the payer aims to maximize the system's long-term surplus with a limited budget,several different results are obtained.These results can provide practical insights for policymakers to coordinate downstream referral programs.
基金This research is supported in part by the National Natural Science Foundation of China under Grant 71420107028, in part by Hong Kong Research Grant Council under Grant T32-102/14-N and in part by the National Natural Science Foundation of China under Grant 71501027.
文摘This paper focuses on an outpatient capacity allocation problem where the patient demand is quite higher than the supply. We study an adding capacity policy to mitigate the mismatch between supply and demand. Under this policy, the doctor is allowed to add capacity if all regular capacity have been booked. A capacity allocation model is formulated for both possible no-show routine patients and all show-up same-day patients. The purpose is to determine the number of capacity can be added and how to allocate regular capacity among routine patients and same-day patients, towards maximizing the expected profit, which is composed of the expected income minus the cost of weighted expected doctor＇s overload work caused by the adding capacity policy and the cost of rejecting patients. To achieve the aims, we prove the expected profit monotonously decreases when the number of additional capacity exceeds a threshold, and present a two-tier enumeration search algorithm to fred the global optimal solution based on the proof. Numerical results indicate that the proposed policy performs well under different levels of demand higher than supply. The optimal number of the additional capacity is hardly affected by varying total expected patient demand. Additionally, under the change of no-show rate, the number of regular capacity allocated to routine patients becomes more stable, compared with the optimal scheme without considering adding capacity policy.
