In cellular systems,establishing the initial symbol timing of potential preambles is the first step of a cell search.The envelope fluctuation of the downlink signal hinders the successful timing of conventional symbol...In cellular systems,establishing the initial symbol timing of potential preambles is the first step of a cell search.The envelope fluctuation of the downlink signal hinders the successful timing of conventional symbol timing methods.To solve this problem,a hybrid timing strategy is proposed with two novel detectors,namely the normalized replica-based detector and normalized differential detector.The strategy first detects all potential preambles via the normalized replica-based detector and then employs the normalized differential detector to verify the target preamble,which comes from the target cell and has the highest power.The strategy is unaffected by envelope fluctuation and has computational complexity comparable to that of conventional methods.Simu-lations and real-data tests show that the hybrid timing strategy is robust and practical for initial symbol timing.展开更多
In downlink cellular multiple users in multiple cells systems using beams, the should cooperate to generate beams to improve the spectrum efficiency. A mathematical model for the multi-cell multi-user downlink transm...In downlink cellular multiple users in multiple cells systems using beams, the should cooperate to generate beams to improve the spectrum efficiency. A mathematical model for the multi-cell multi-user downlink transmission is established, and the gradients of the variables including beamfonning filters, receiving filters and transmitting power are calculated. Then, a gradient-project-based cooperative beamforming scheme is proposed in which each user iteratively adjusts bearnforming variables in the direction of the gradients and projects onto feasible spaces. The information exchange protocol needed to support the scheme is also described. Simulation results show that the proposed scheme can achieve an average spectral efficiency of about 5 bit/（ s · Hz · cell）. The results show that cooperative beamforming can improve the spectrum efficiency of the cellular systems.展开更多
Recently, the multi-hop cellular networks have been widely studied in order to enhance the cell performances such as the cell capacity. While most of these works merely use the multi-hop methods instead of direct tran...Recently, the multi-hop cellular networks have been widely studied in order to enhance the cell performances such as the cell capacity. While most of these works merely use the multi-hop methods instead of direct transmission without considering the co-channel inter-cell interference, signal transmission mode and the effects of the number of antennas. With the consideration of above important elements, this paper proposed an improved cellular system with multi-relay amplifies-andforward （AF） cooperative transmission scheme and the corresponding capacity expression is derived under the corresponding environment. By using the potential space diversity and selecting relays based on maximizing the capacity, the cellular system capacity can be improved effectively. The simulation results show that with the assistance of optimal selected relays, the improved cooperative cellular system capacity with multi-relay AF transmission scheme performs better than single-hop cellular system.展开更多
Within a cell of cellular system,cooperative relay technique can improve the performance of multicast efficiently,but it can cause the stream frequent interruptions because of the mobility of relay terminals.A video l...Within a cell of cellular system,cooperative relay technique can improve the performance of multicast efficiently,but it can cause the stream frequent interruptions because of the mobility of relay terminals.A video layered cooperative relay strategy is proposed to guarantee the continuity of multicast stream and retain high-bandwidth of the cooperative relay channel.Based on the capacity analysis for layered relay channel in the strategy,the optimal power allocation is studied to maximize capacity.After analyzing and optimizing the capacity in abstract models,the study is extended to a non-fading and a Gaussian wireless channel model to satisfy the scenario of cellular system.Giving the relay nodes position or distribution of noise power,the obtained results can determine the optimal power allocation among the transmitter and relay nodes.At last,the simulation results show that the strategy and its optimal power allocation have a significant improvement on the performance.展开更多
This paper presented a scheme of relayed cellular mobile telecommunication network,which only employs fixed digital relays and not more than two-hop relay routes.Power saving potential of the network is deeply studied...This paper presented a scheme of relayed cellular mobile telecommunication network,which only employs fixed digital relays and not more than two-hop relay routes.Power saving potential of the network is deeply studied under the assumption of not occupying additional frequency bands(i.e.relays share the same frequency bands as used by the base stations).Theoretical analysis and simulation results have both shown that,with the same radio coverage requirement,the necessary effective transmission powers in such a relayed network have greatly decreased compared to conventional cellular network.展开更多
In this paper, an asynchronous cooperative cellular system applied with space-time block coding (STBC) is investigated. A signal detector is proposed based on parallel interference cancellation (PIC), to cancel the in...In this paper, an asynchronous cooperative cellular system applied with space-time block coding (STBC) is investigated. A signal detector is proposed based on parallel interference cancellation (PIC), to cancel the inter-symbol interference (ISI) caused by the imperfect synchronization. Simulation results show that the proposed PIC detector can effiectively suppress the ISI, but there is still a comparatively high error floor, due to the co-channel interference (CCI) of the cellular system.展开更多
It is known that dynamic channel assignment(D CA ) strategy outperforms the fixed channel assignment(FCA) strategy in omni-direc tional antenna cellular systems. One of the most important methods used in DCA w as chan...It is known that dynamic channel assignment(D CA ) strategy outperforms the fixed channel assignment(FCA) strategy in omni-direc tional antenna cellular systems. One of the most important methods used in DCA w as channel borrowing. But with the emergence of cell sectorization and spatial d ivision multiple access(SDMA) which are used to increase the capacity of cel lular systems, the channel assignment faces a series of new problems. In this pa per, a dynamic channel allocation scheme based on sectored cellular systems is p roposed. By introducing intra-cell channel borrowing (borrowing channels from n eighboring sectors) and inter-cell channel borrowing (borrowing channels from n eighboring cells) methods, previous DCA strategies, including compact pattern ba sed channel borrowing(CPCB) and greedy based dynamic channel assignment(GDCA) schemes proposed by the author, are improved significantly. The computer simu lation shows that either intra-cell borrowing scheme or inter-cell borrowing s cheme is efficient enough to uniform and non-uniform traffic service distributi ons.展开更多
This paper presents an efficient Radio Resource Management (RRM) strategy for adaptive Orthogo-nal Frequency Division Multiplexing (OFDM) cellular systems. In the proposed strategy, only those users who have the same ...This paper presents an efficient Radio Resource Management (RRM) strategy for adaptive Orthogo-nal Frequency Division Multiplexing (OFDM) cellular systems. In the proposed strategy, only those users who have the same distance from their base stations can reuse a same subcarrier. This can guarantee the received Carrier-to-Interference ratio (C/I) of each subcarrier to be acceptable as required by system planning. Then by employing different modulation scheme on each subcarrier according to its received C/I, system spectral effi-ciency can be gracefully increased. Analytical and simulation results show that the spectral efficiency is im-proved by 40% without sacrificing the Bit Error Rate (BER) performance and call blocking probability and sys-tem capacity of the proposed strategy is better than conventional systems.展开更多
The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as w...The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as well as the wireless multi-media services.It is predicted that the network throughput will increase展开更多
Multi-criteria handoff algorithms have been playing a more important role than the traditional handoff algorithms.In order to balance the satisfaction of users and the efficiency of networks,it is necessary to develop...Multi-criteria handoff algorithms have been playing a more important role than the traditional handoff algorithms.In order to balance the satisfaction of users and the efficiency of networks,it is necessary to develop new technologies to improve the validity of handoff algorithms.Intelligent and optimized handoff algorithms in hybrid networks that integrate Ad hoc and mobile cellular systems are well-adaptive and robust.They are able to implement handoffs adaptively,according to specific multi-factors such as different Quality of Service(QoS)requirements,network states and mobile node conditions in the future hybrid networks.Therefore,these intelligent and optimized algorithms can make more effective handover decision,and accordingly improve the system’s performance.The future research will tackle intelligent or optimized vertical handoff algorithms for integrated Ad hoc and mobile cellular networks to improve their whole system performance.展开更多
This paper focuses on the problem of secure transmission in a cellular system. A full-duplex base station using artificial noise is adopted to improve both the uplink and downlink secrecy rate via pairing terminals wh...This paper focuses on the problem of secure transmission in a cellular system. A full-duplex base station using artificial noise is adopted to improve both the uplink and downlink secrecy rate via pairing terminals which reverses the downlink and uplink of each other. We give the designs of artificial noise and the user's desired signal, and derive the pairing prin-ciple between terminals. Moreover, the influence of self-interference cancellation on secrecy rate is ex-plored. Simulation results show that the secrecy rate can get much better performance by adopting full-duplex artificial noise scheme and proposed pair-ing method. The downlink secrecy rate decreases with the distance between terminals. Besides the uplink secrecy rate is sensitive to the ability of self-interference cancellation.展开更多
This paper proposes the concept of inter-cell relay for downlink orthogonal frequency division multiple access(OFDMA) cellular systems, which uses multi-hop to relay calls from overloaded cells to light-load neighbori...This paper proposes the concept of inter-cell relay for downlink orthogonal frequency division multiple access(OFDMA) cellular systems, which uses multi-hop to relay calls from overloaded cells to light-load neighboring cells. It is shown that when using inter-cell relay, the number of calls in the congestion cell can be significantly increased. The congestion cell is divided into two parts. One is called non-relay area(NRA), in which a call directly communicates with the base station(BS) of a congested cell. The other is called relay area(RA), in which a call communicates with the BS of a neighboring cell through a relay station(RS). The two parts have different user-call densities. By adjusting the densities of two parts, we will maximize the number of supported calls inside a congested cell. The results show the benefits gained from inter-cell relay in congestion relief, which can reduce cell congestion by fully utilizing the available resources in the neighboring cells.展开更多
Power control is an important technique in WCDMA mobile systems for both increasing system capacity and guaranteeing the required QoS (time delay and wireless link transmission quality) of multimedia services. The opt...Power control is an important technique in WCDMA mobile systems for both increasing system capacity and guaranteeing the required QoS (time delay and wireless link transmission quality) of multimedia services. The optimum power control for narrow band CDMA cellular systems is a problem of single threshold optimization. Because these systems have only one type of traffic and have the same QoS requirement. However, WCDMA mobile system should provide multimedia services and different types of traffic have different QoS requirements. Thus, the power control in WCDMA mobile systems isn't a problem of single threshold optimizing, but turns into the optimizing problem of multi-threshold. We analyze the power control problem in WCDMA cellular mobile systems and propose the optimum transmitter power control algorithm. Three criteria to optimize transmitter power levels of multi-thresholds based on grading the priority orders of multimedia services are proposed. Simulation results show that the proposed algorithms are more effective than conventional algorithms and can provide better performance for WCDMA cellular mobile systems.展开更多
It is widely believed that cooperative relay technologies can improve the throughput of multicasting in mobile cellular networks significantly, however, the mobility of the relay terrninals may cause frequent relay li...It is widely believed that cooperative relay technologies can improve the throughput of multicasting in mobile cellular networks significantly, however, the mobility of the relay terrninals may cause frequent relay link outage. This paper proposes a stream layered cooperative relay scheme to deal with this problem. In order to study the characteristics of layered relay channels in the scheme, the capacity region is determined based on a single and a multi relay abstract model with streams layering. Besides, to satisfy the cellular network scenario, the results are extended to a wireless Gaussian channel model. The analysis and simulation results show that the scheme guarantees the continuity of the multicast streams, and maintains the high bandwidth of relay channel, with a slight loss on system capacity.展开更多
Land use/land cover represents the interactive and comprehensive influences between human activities and natural conditions,leading to potential conflicts among natural and human-related issues as well as among stakeh...Land use/land cover represents the interactive and comprehensive influences between human activities and natural conditions,leading to potential conflicts among natural and human-related issues as well as among stakeholders.This study introduced economic standards for farmers.A hybrid approach(CA-ABM)of cellular automaton(CA)and an agent-based model(ABM)was developed to effectively deal with social and land-use synergic issues to examine human–environment interactions and projections of land-use conversions for a humid basin in south China.Natural attributes and socioeconomic data were used to analyze land use/land cover and its drivers of change.The major modules of the CA-ABM are initialization,migration,assets,land suitability,and land-use change decisions.Empirical estimates of the factors influencing the urban land-use conversion probability were captured using parameters based on a spatial logistic regression(SLR)model.Simultaneously,multicriteria evaluation(MCE)and Markov models were introduced to obtain empirical estimates of the factors affecting the probability of ecological land conversion.An agent-based CA-SLR-MCE-Markov(ABCSMM)land-use conversion model was proposed to explore the impacts of policies on land-use conversion.This model can reproduce observed land-use patterns and provide links for forest transition and urban expansion to land-use decisions and ecosystem services.The results demonstrated land-use simulations under multi-policy scenarios,revealing the usefulness of the model for normative research on land-use management.展开更多
BACKGROUND Alzheimer’s disease(AD)is a serious disease causing human dementia and social problems.The quality of life and prognosis of AD patients have attracted much attention.The role of chronic immune inflammation...BACKGROUND Alzheimer’s disease(AD)is a serious disease causing human dementia and social problems.The quality of life and prognosis of AD patients have attracted much attention.The role of chronic immune inflammation in the pathogenesis of AD is becoming more and more important.AIM To study the relationship among cognitive dysfunction,abnormal cellular immune function,neuroimaging results and poor prognostic factors in patients.METHODS A retrospective analysis of 62 hospitalized patients clinical diagnosed with AD who were admitted to our hospital from November 2015 to November 2020.Collect cognitive dysfunction performance characteristics,laboratory test data and neuroimaging data from medical records within 24 h of admission,including Mini Mental State Examination Scale score,drawing clock test,blood T lymphocyte subsets,and neutrophils and lymphocyte ratio(NLR),disturbance of consciousness,extrapyramidal symptoms,electroencephalogram(EEG)and head nucleus magnetic spectroscopy(MRS)and other data.Multivariate logistic regression analysis was used to determine independent prog-nostic factors.the modified Rankin scale(mRS)was used to determine whether the prognosis was good.The correlation between drug treatment and prognostic mRS score was tested by the rank sum test.RESULTS Univariate analysis showed that abnormal cellular immune function,extrapyramidal symptoms,obvious disturbance of consciousness,abnormal EEG,increased NLR,abnormal MRS,and complicated pneumonia were related to the poor prognosis of AD patients.Multivariate logistic regression analysis showed that the decrease in the proportion of T lym-phocytes in the blood after abnormal cellular immune function(odd ratio:2.078,95%confidence interval:1.156-3.986,P<0.05)was an independent risk factor for predicting the poor prognosis of AD.The number of days of donepezil treatment to improve cognitive function was negatively correlated with mRS score(r=0.578,P<0.05).CONCLUSION The decrease in the proportion of T lymphocytes may have predictive value for the poor prognosis of AD.It is recommended that the proportion of T lymphocytes<55%is used as the cut-off threshold for predicting the poor prog-nosis of AD.The early and continuous drug treatment is associated with a good prognosis.展开更多
BACKGROUND An increasing number of studies have focused on the role of cellular metabolism in the development of colorectal cancer(CRC).However,no work is currently available to synthesize the field through bibliometr...BACKGROUND An increasing number of studies have focused on the role of cellular metabolism in the development of colorectal cancer(CRC).However,no work is currently available to synthesize the field through bibliometrics.AIM To analyze the development in the field of“glucose metabolism”(GM),“amino acid metabolism”(AM),“lipid metabolism”(LM),and“nucleotide metabolism”(NM)in CRC by visualization.METHODS Articles within the abovementioned areas of GM,AM,LM and NM in CRC,which were published from January 1,1991,to December 31,2022,are retrieved from the Web of Science Core Collection and analyzed by CiteSpace 6.2.R4 and VOSviewer 1.6.19.RESULTS The field of LM in CRC presented the largest number of annual publications and the fastest increase in the last decade compared with the other three fields.Meanwhile,China and the United States were two of the most prominent contri-butors in these four areas.In addition,Gang Wang,Wei Jia,Maria Notar-nicola,and Cornelia Ulrich ranked first in publication numbers,while Jing-Yuan Fang,Senji Hirasawa,Wei Jia,and Charles Fuchs were the most cited authors on average in these four fields,respectively.“Gut microbiota”and“epithelial-mesenchymal transition”emerged as the newest burst words in GM,“gut microbiota”was the latest outburst word in AM,“metastasis”,“tumor microenvironment”,“fatty acid metabolism”,and“metabolic reprogramming”were the up-to-date outbreaking words in LM,while“epithelial-mesenchymal transition”and“apoptosis”were the most recently occurring words in NM.CONCLUSION Research in“cellular metabolism in CRC”is all the rage at the moment,and researchers are particularly interested in exploring the mechanism to explain the metabolic alterations in CRC.Targeting metabolic vulnerability appears to be a promising direction in CRC therapy.展开更多
1.Introduction Cell structure and function are controlled by a complex regulatory networking process,in which molecular adaptation and interaction are essential to maintain cellular homeostasis following dynamic multi...1.Introduction Cell structure and function are controlled by a complex regulatory networking process,in which molecular adaptation and interaction are essential to maintain cellular homeostasis following dynamic multi-omics rules and multi-systematic changes.This complex chemical process is an important mechanism for stabilizing the cell microenvironment.展开更多
Unlike chemosynthetic drugs designed for specific molecular and disease targets,active small-molecule natural products typically have a wide range of bioactivities and multiple targets,necessitating extensive screenin...Unlike chemosynthetic drugs designed for specific molecular and disease targets,active small-molecule natural products typically have a wide range of bioactivities and multiple targets,necessitating extensive screening and development.To address this issue,we propose a strategy for the direct in situ microdynamic examination of potential drug candidates to rapidly identify their effects and mechanisms of action.As a proof-of-concept,we investigated the behavior of mussel oligosaccharide(MOS-1)by tracking the subcellular dynamics of fluorescently labeled MOS-1 in cultured cells.We recorded the entire dynamic process of the localization of fluorescein isothiocyanate(FITC)-MOS-1 to the lysosomes and visualized the distribution of the drug within the cell.Remarkably,lysosomes containing FITC-MOS-1 actively recruited lipid droplets,leading to fusion events and increased cellular lipid consumption.These drug behaviors confirmed MOS-1 is a candidate for the treatment of lipid-related diseases.Furthermore,in a high-fat HepG2 cell model and in high-fat diet-fed apolipoprotein E(ApoE)^(-/-)mice,MOS-1 significantly promoted triglyceride degradation,reduced lipid droplet accumulation,lowered serum triglyceride levels,and mitigated liver damage and steatosis.Overall,our work supports the prioritization of in situ visual monitoring of drug location and distribution in subcellular compartments during the drug development phase,as this methodology contributes to the rapid identification of drug indications.Collectively,this methodology is significant for the screening and development of selective small-molecule drugs,and is expected to expedite the identification of candidate molecules with medicinal effects.展开更多
Cellular senescence is the results of aging and age-related diseases,and the development of anti-aging methods may improve health and extend longevity.The natural flavonol fisetin has been shown to antagonize senescen...Cellular senescence is the results of aging and age-related diseases,and the development of anti-aging methods may improve health and extend longevity.The natural flavonol fisetin has been shown to antagonize senescence in vitro and increases longevity in vivo,but has poor water solubility and limited bioavailability.In this study,a food-grade and senescent cell-targeted delivery system for fisetin was developed based on whey protein isolate-galactooligosaccharides(WPI-GOS)Maillard conjugate,which could recognize senescence associatedβ-galactosidase in senescent cells.The fisetin nanoparticles possessed a high encapsulation efficiency,excellent dispersibility in water,good storage stability and well biocompatibility.Moreover,they could effectively accumulate and retain in senescent cells with excellent senescent cell-targeting efficacy,and inhibit the oxidative stress-induced cellular senescence in vitro.Thus,this novel nanoparticle system based on WPI-GOS Maillard conjugate showed promise to deliver hydrophobic bioactive ingredients like fisetin to senescent cells to improve their bioavailability and anti-senescence effect.展开更多
基金supported in part by the National Natural Science Foundation of China(61931015,62071335)in part by the Natural Science Foundation of Hubei Province of China(2021CFA002)+2 种基金in part by the Fundamental Research Funds for the Central Universitiesin part by the Technological Innovation Project of Hubei Province of China(2019AAA061)in part by the Science and Technology Program of Shenzhen(JCYJ20170818112037398).
文摘In cellular systems,establishing the initial symbol timing of potential preambles is the first step of a cell search.The envelope fluctuation of the downlink signal hinders the successful timing of conventional symbol timing methods.To solve this problem,a hybrid timing strategy is proposed with two novel detectors,namely the normalized replica-based detector and normalized differential detector.The strategy first detects all potential preambles via the normalized replica-based detector and then employs the normalized differential detector to verify the target preamble,which comes from the target cell and has the highest power.The strategy is unaffected by envelope fluctuation and has computational complexity comparable to that of conventional methods.Simu-lations and real-data tests show that the hybrid timing strategy is robust and practical for initial symbol timing.
基金The National Natural Science Foundation of China(No.61001103)the National Science and Technology Major Project of China (No.2008ZX03003-005)the National Basic Research Program ofChina(973 Program) (No.2007CB310603)
文摘In downlink cellular multiple users in multiple cells systems using beams, the should cooperate to generate beams to improve the spectrum efficiency. A mathematical model for the multi-cell multi-user downlink transmission is established, and the gradients of the variables including beamfonning filters, receiving filters and transmitting power are calculated. Then, a gradient-project-based cooperative beamforming scheme is proposed in which each user iteratively adjusts bearnforming variables in the direction of the gradients and projects onto feasible spaces. The information exchange protocol needed to support the scheme is also described. Simulation results show that the proposed scheme can achieve an average spectral efficiency of about 5 bit/（ s · Hz · cell）. The results show that cooperative beamforming can improve the spectrum efficiency of the cellular systems.
基金Project supported by the Shanghai Leading Academic Discipline Project (Grant No.S30108)the Science and Technology Commission of Shanghai Municipality (Grant No.08DZ2231100)+1 种基金the Shanghai Pujiang Program (Grant No.08PJ14057)the Graduate Student Innovation Foundation of Shanghai University (Grant No.SHUCX080151)
文摘Recently, the multi-hop cellular networks have been widely studied in order to enhance the cell performances such as the cell capacity. While most of these works merely use the multi-hop methods instead of direct transmission without considering the co-channel inter-cell interference, signal transmission mode and the effects of the number of antennas. With the consideration of above important elements, this paper proposed an improved cellular system with multi-relay amplifies-andforward （AF） cooperative transmission scheme and the corresponding capacity expression is derived under the corresponding environment. By using the potential space diversity and selecting relays based on maximizing the capacity, the cellular system capacity can be improved effectively. The simulation results show that with the assistance of optimal selected relays, the improved cooperative cellular system capacity with multi-relay AF transmission scheme performs better than single-hop cellular system.
基金Sponsored by State Key Program of National Natural Science of China(Grant No.60832009)Natural Science Foundation of Beijing,China(Grant No.4102044)+1 种基金Innovative Project for Young Researchers in Central Higher Education Institutions,China(Grant No.2009RC0119New Generation of Broadband Wireless Mobile Communication Networks of Major Projects of National Science and Technology(Grant No.2009ZX03003-003-01)
文摘Within a cell of cellular system,cooperative relay technique can improve the performance of multicast efficiently,but it can cause the stream frequent interruptions because of the mobility of relay terminals.A video layered cooperative relay strategy is proposed to guarantee the continuity of multicast stream and retain high-bandwidth of the cooperative relay channel.Based on the capacity analysis for layered relay channel in the strategy,the optimal power allocation is studied to maximize capacity.After analyzing and optimizing the capacity in abstract models,the study is extended to a non-fading and a Gaussian wireless channel model to satisfy the scenario of cellular system.Giving the relay nodes position or distribution of noise power,the obtained results can determine the optimal power allocation among the transmitter and relay nodes.At last,the simulation results show that the strategy and its optimal power allocation have a significant improvement on the performance.
基金National Science Fund for Creative ResearchGroups(No.60521002)Chinese NationalKey Technology R&D Program(No.2005BA908B02)Science Foundation ofShanghai Municipal Commission of Scienceand Technology,Chinese(No.05dz05802)
文摘This paper presented a scheme of relayed cellular mobile telecommunication network,which only employs fixed digital relays and not more than two-hop relay routes.Power saving potential of the network is deeply studied under the assumption of not occupying additional frequency bands(i.e.relays share the same frequency bands as used by the base stations).Theoretical analysis and simulation results have both shown that,with the same radio coverage requirement,the necessary effective transmission powers in such a relayed network have greatly decreased compared to conventional cellular network.
基金supported by the Shanghai Pujiang Program (Grant No.08PJ14057)the Science Foundation of Science and Technology Commission of Shanghai Municipality (Grant No.08220510900)
文摘In this paper, an asynchronous cooperative cellular system applied with space-time block coding (STBC) is investigated. A signal detector is proposed based on parallel interference cancellation (PIC), to cancel the inter-symbol interference (ISI) caused by the imperfect synchronization. Simulation results show that the proposed PIC detector can effiectively suppress the ISI, but there is still a comparatively high error floor, due to the co-channel interference (CCI) of the cellular system.
文摘It is known that dynamic channel assignment(D CA ) strategy outperforms the fixed channel assignment(FCA) strategy in omni-direc tional antenna cellular systems. One of the most important methods used in DCA w as channel borrowing. But with the emergence of cell sectorization and spatial d ivision multiple access(SDMA) which are used to increase the capacity of cel lular systems, the channel assignment faces a series of new problems. In this pa per, a dynamic channel allocation scheme based on sectored cellular systems is p roposed. By introducing intra-cell channel borrowing (borrowing channels from n eighboring sectors) and inter-cell channel borrowing (borrowing channels from n eighboring cells) methods, previous DCA strategies, including compact pattern ba sed channel borrowing(CPCB) and greedy based dynamic channel assignment(GDCA) schemes proposed by the author, are improved significantly. The computer simu lation shows that either intra-cell borrowing scheme or inter-cell borrowing s cheme is efficient enough to uniform and non-uniform traffic service distributi ons.
基金Supported by the National Natural Science Foundation of China (No.60002003) and National Hi-Tech Research and Development Project of China (No.2002AA123044).
文摘This paper presents an efficient Radio Resource Management (RRM) strategy for adaptive Orthogo-nal Frequency Division Multiplexing (OFDM) cellular systems. In the proposed strategy, only those users who have the same distance from their base stations can reuse a same subcarrier. This can guarantee the received Carrier-to-Interference ratio (C/I) of each subcarrier to be acceptable as required by system planning. Then by employing different modulation scheme on each subcarrier according to its received C/I, system spectral effi-ciency can be gracefully increased. Analytical and simulation results show that the spectral efficiency is im-proved by 40% without sacrificing the Bit Error Rate (BER) performance and call blocking probability and sys-tem capacity of the proposed strategy is better than conventional systems.
文摘The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as well as the wireless multi-media services.It is predicted that the network throughput will increase
基金This work was funded by the High- tech Research and Development Program of China (863 Program) under Grant 2006AA01Z208.
文摘Multi-criteria handoff algorithms have been playing a more important role than the traditional handoff algorithms.In order to balance the satisfaction of users and the efficiency of networks,it is necessary to develop new technologies to improve the validity of handoff algorithms.Intelligent and optimized handoff algorithms in hybrid networks that integrate Ad hoc and mobile cellular systems are well-adaptive and robust.They are able to implement handoffs adaptively,according to specific multi-factors such as different Quality of Service(QoS)requirements,network states and mobile node conditions in the future hybrid networks.Therefore,these intelligent and optimized algorithms can make more effective handover decision,and accordingly improve the system’s performance.The future research will tackle intelligent or optimized vertical handoff algorithms for integrated Ad hoc and mobile cellular networks to improve their whole system performance.
基金supported in part by National Natural Science Foundation of China under Grants No.61379006,61401510,61501516,61471396 and 61521003Research and Development Program of China(863 Program)under Grant No.2014AA01A701The Open Research Fund of National Mobile Communications Research Laboratory,Southeast University under Grants No.2013D09
文摘This paper focuses on the problem of secure transmission in a cellular system. A full-duplex base station using artificial noise is adopted to improve both the uplink and downlink secrecy rate via pairing terminals which reverses the downlink and uplink of each other. We give the designs of artificial noise and the user's desired signal, and derive the pairing prin-ciple between terminals. Moreover, the influence of self-interference cancellation on secrecy rate is ex-plored. Simulation results show that the secrecy rate can get much better performance by adopting full-duplex artificial noise scheme and proposed pair-ing method. The downlink secrecy rate decreases with the distance between terminals. Besides the uplink secrecy rate is sensitive to the ability of self-interference cancellation.
基金National Natural Science Foundation of China under grant number (61872186,61872193)The National Natural Science Foundation of China for Youth (61201160, 61602263)+8 种基金The Natural Science Foundation of Jiangsu Province (BK20131377, BK20151507, BK20160916)The Natural science fund for colleges and universities in Jiangsu Province under Grants (16KJB510034)The six talent peaks project in Jiangsu Province (XYDXXJS-044)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (yx002001)The Jiangsu Overseas Research and Training Program for University Prominent Young and Middle-aged Teachers and PresidentsSponsored by NUPTSF (Grant Nos. NY212012, NY214065,NY216020)The Six Talented Eminence Foundation of Jiangsu Province (No. XYDXXJS-044)The 333 High-level Talents Training Project of Jiangsu ProvinceThe 1311 Talents Plan of NUPT and the China Postdoctoral Science Foundation (No. 2018M630590)
文摘This paper proposes the concept of inter-cell relay for downlink orthogonal frequency division multiple access(OFDMA) cellular systems, which uses multi-hop to relay calls from overloaded cells to light-load neighboring cells. It is shown that when using inter-cell relay, the number of calls in the congestion cell can be significantly increased. The congestion cell is divided into two parts. One is called non-relay area(NRA), in which a call directly communicates with the base station(BS) of a congested cell. The other is called relay area(RA), in which a call communicates with the BS of a neighboring cell through a relay station(RS). The two parts have different user-call densities. By adjusting the densities of two parts, we will maximize the number of supported calls inside a congested cell. The results show the benefits gained from inter-cell relay in congestion relief, which can reduce cell congestion by fully utilizing the available resources in the neighboring cells.
文摘Power control is an important technique in WCDMA mobile systems for both increasing system capacity and guaranteeing the required QoS (time delay and wireless link transmission quality) of multimedia services. The optimum power control for narrow band CDMA cellular systems is a problem of single threshold optimization. Because these systems have only one type of traffic and have the same QoS requirement. However, WCDMA mobile system should provide multimedia services and different types of traffic have different QoS requirements. Thus, the power control in WCDMA mobile systems isn't a problem of single threshold optimizing, but turns into the optimizing problem of multi-threshold. We analyze the power control problem in WCDMA cellular mobile systems and propose the optimum transmitter power control algorithm. Three criteria to optimize transmitter power levels of multi-thresholds based on grading the priority orders of multimedia services are proposed. Simulation results show that the proposed algorithms are more effective than conventional algorithms and can provide better performance for WCDMA cellular mobile systems.
基金Supported by the State Key Program of National Natural Science Foundation of China （No. 60832009）, Natural Science Foundation of Bcijing （No. 4102044）, Innovative Project for Young Researchers in Central Higher Education Institutions, China （No. 2009RC0119） and New Generation of Broadband Wireless Mobile Communication Networks of Major Projects of National Science and Technology （No.2009ZX03003-003-01）.
文摘It is widely believed that cooperative relay technologies can improve the throughput of multicasting in mobile cellular networks significantly, however, the mobility of the relay terrninals may cause frequent relay link outage. This paper proposes a stream layered cooperative relay scheme to deal with this problem. In order to study the characteristics of layered relay channels in the scheme, the capacity region is determined based on a single and a multi relay abstract model with streams layering. Besides, to satisfy the cellular network scenario, the results are extended to a wireless Gaussian channel model. The analysis and simulation results show that the scheme guarantees the continuity of the multicast streams, and maintains the high bandwidth of relay channel, with a slight loss on system capacity.
基金supported by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2021ZT090543)the National Natural Science Foundation of China(U20A20117)the Key-Area Research and Development Program of Guangdong Province(2020B1111380003).
文摘Land use/land cover represents the interactive and comprehensive influences between human activities and natural conditions,leading to potential conflicts among natural and human-related issues as well as among stakeholders.This study introduced economic standards for farmers.A hybrid approach(CA-ABM)of cellular automaton(CA)and an agent-based model(ABM)was developed to effectively deal with social and land-use synergic issues to examine human–environment interactions and projections of land-use conversions for a humid basin in south China.Natural attributes and socioeconomic data were used to analyze land use/land cover and its drivers of change.The major modules of the CA-ABM are initialization,migration,assets,land suitability,and land-use change decisions.Empirical estimates of the factors influencing the urban land-use conversion probability were captured using parameters based on a spatial logistic regression(SLR)model.Simultaneously,multicriteria evaluation(MCE)and Markov models were introduced to obtain empirical estimates of the factors affecting the probability of ecological land conversion.An agent-based CA-SLR-MCE-Markov(ABCSMM)land-use conversion model was proposed to explore the impacts of policies on land-use conversion.This model can reproduce observed land-use patterns and provide links for forest transition and urban expansion to land-use decisions and ecosystem services.The results demonstrated land-use simulations under multi-policy scenarios,revealing the usefulness of the model for normative research on land-use management.
基金Supported by the National Natural Science Foundation of China,No.3206080019 and No.32060182Science and Technology Support Plan of Guizhou Province in China,No.[2020]4Y129Qiannan Prefecture Science and Technology Plan Project,No.[2022]01.
文摘BACKGROUND Alzheimer’s disease(AD)is a serious disease causing human dementia and social problems.The quality of life and prognosis of AD patients have attracted much attention.The role of chronic immune inflammation in the pathogenesis of AD is becoming more and more important.AIM To study the relationship among cognitive dysfunction,abnormal cellular immune function,neuroimaging results and poor prognostic factors in patients.METHODS A retrospective analysis of 62 hospitalized patients clinical diagnosed with AD who were admitted to our hospital from November 2015 to November 2020.Collect cognitive dysfunction performance characteristics,laboratory test data and neuroimaging data from medical records within 24 h of admission,including Mini Mental State Examination Scale score,drawing clock test,blood T lymphocyte subsets,and neutrophils and lymphocyte ratio(NLR),disturbance of consciousness,extrapyramidal symptoms,electroencephalogram(EEG)and head nucleus magnetic spectroscopy(MRS)and other data.Multivariate logistic regression analysis was used to determine independent prog-nostic factors.the modified Rankin scale(mRS)was used to determine whether the prognosis was good.The correlation between drug treatment and prognostic mRS score was tested by the rank sum test.RESULTS Univariate analysis showed that abnormal cellular immune function,extrapyramidal symptoms,obvious disturbance of consciousness,abnormal EEG,increased NLR,abnormal MRS,and complicated pneumonia were related to the poor prognosis of AD patients.Multivariate logistic regression analysis showed that the decrease in the proportion of T lym-phocytes in the blood after abnormal cellular immune function(odd ratio:2.078,95%confidence interval:1.156-3.986,P<0.05)was an independent risk factor for predicting the poor prognosis of AD.The number of days of donepezil treatment to improve cognitive function was negatively correlated with mRS score(r=0.578,P<0.05).CONCLUSION The decrease in the proportion of T lymphocytes may have predictive value for the poor prognosis of AD.It is recommended that the proportion of T lymphocytes<55%is used as the cut-off threshold for predicting the poor prog-nosis of AD.The early and continuous drug treatment is associated with a good prognosis.
基金National Natural Science Foundation of China,No.82173063 and No.81972220Wuxi Taihu Lake Talent Plan Supporting for Leading Talents in Medical and Health Profession+2 种基金Wuxi Medical Key Discipline,No.ZDXK2021002China Postdoctoral Science Foundation,No.2022M711370Postgraduate Research&Practice Innovation Program of Jiangsu Province,No.KYCX23_2573.
文摘BACKGROUND An increasing number of studies have focused on the role of cellular metabolism in the development of colorectal cancer(CRC).However,no work is currently available to synthesize the field through bibliometrics.AIM To analyze the development in the field of“glucose metabolism”(GM),“amino acid metabolism”(AM),“lipid metabolism”(LM),and“nucleotide metabolism”(NM)in CRC by visualization.METHODS Articles within the abovementioned areas of GM,AM,LM and NM in CRC,which were published from January 1,1991,to December 31,2022,are retrieved from the Web of Science Core Collection and analyzed by CiteSpace 6.2.R4 and VOSviewer 1.6.19.RESULTS The field of LM in CRC presented the largest number of annual publications and the fastest increase in the last decade compared with the other three fields.Meanwhile,China and the United States were two of the most prominent contri-butors in these four areas.In addition,Gang Wang,Wei Jia,Maria Notar-nicola,and Cornelia Ulrich ranked first in publication numbers,while Jing-Yuan Fang,Senji Hirasawa,Wei Jia,and Charles Fuchs were the most cited authors on average in these four fields,respectively.“Gut microbiota”and“epithelial-mesenchymal transition”emerged as the newest burst words in GM,“gut microbiota”was the latest outburst word in AM,“metastasis”,“tumor microenvironment”,“fatty acid metabolism”,and“metabolic reprogramming”were the up-to-date outbreaking words in LM,while“epithelial-mesenchymal transition”and“apoptosis”were the most recently occurring words in NM.CONCLUSION Research in“cellular metabolism in CRC”is all the rage at the moment,and researchers are particularly interested in exploring the mechanism to explain the metabolic alterations in CRC.Targeting metabolic vulnerability appears to be a promising direction in CRC therapy.
基金supported by the Major Program(82293651)the Key Program(82130055)of National Natural Science Foundation of China,the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(2019-I2M-5-055)the“Pioneer”and“Leading Goose”Research and Development(R&D)Program of Zhejiang(2023C03004).
文摘1.Introduction Cell structure and function are controlled by a complex regulatory networking process,in which molecular adaptation and interaction are essential to maintain cellular homeostasis following dynamic multi-omics rules and multi-systematic changes.This complex chemical process is an important mechanism for stabilizing the cell microenvironment.
基金supported by Shandong Province Key R&D Program,China(Major Technological Innovation Project)(Grant No.:2021CXGC010501)Young Elite Scientists Sponsorship Program by China Association of Chinese Medicine,China(Grant No.:CACM-2023-QNRC1-02)+8 种基金the National Natural Science Foundation of China(Grant Nos.:22107059,22007060,82302743)the Natural Science Foundation of Shandong Province,China(Grant Nos.:ZR2022QH304,ZR2021QH057,ZR2020QB166)the Program for Youth Innovation Technology in Colleges and Universities of Shandong Province of China(Grant No.:2021KJ035)Taishan Scholars Program,China(Grant Nos.:TSQN202211221,TSPD20181218)Shandong Science Fund for Excellent Young Scholars,China(Grant No.:ZR2022YQ66)Shandong Province Traditional Chinese Medicine Science and Technology Project,China(Grant No.:Q-2023059)Shenzhen Basic Research Project,China(Grant No.:JCYJ20190809160209449)the General Project of Shandong Natural Science Foundation,China(Grant No.:ZR2021MH341)Jinan Innovation Team Project of Colleges and Universities,China(Grant No.:2021GXRC072).
文摘Unlike chemosynthetic drugs designed for specific molecular and disease targets,active small-molecule natural products typically have a wide range of bioactivities and multiple targets,necessitating extensive screening and development.To address this issue,we propose a strategy for the direct in situ microdynamic examination of potential drug candidates to rapidly identify their effects and mechanisms of action.As a proof-of-concept,we investigated the behavior of mussel oligosaccharide(MOS-1)by tracking the subcellular dynamics of fluorescently labeled MOS-1 in cultured cells.We recorded the entire dynamic process of the localization of fluorescein isothiocyanate(FITC)-MOS-1 to the lysosomes and visualized the distribution of the drug within the cell.Remarkably,lysosomes containing FITC-MOS-1 actively recruited lipid droplets,leading to fusion events and increased cellular lipid consumption.These drug behaviors confirmed MOS-1 is a candidate for the treatment of lipid-related diseases.Furthermore,in a high-fat HepG2 cell model and in high-fat diet-fed apolipoprotein E(ApoE)^(-/-)mice,MOS-1 significantly promoted triglyceride degradation,reduced lipid droplet accumulation,lowered serum triglyceride levels,and mitigated liver damage and steatosis.Overall,our work supports the prioritization of in situ visual monitoring of drug location and distribution in subcellular compartments during the drug development phase,as this methodology contributes to the rapid identification of drug indications.Collectively,this methodology is significant for the screening and development of selective small-molecule drugs,and is expected to expedite the identification of candidate molecules with medicinal effects.
基金supported by Dalian Youth Science and Technology Star Project(2020RQ121)the National Science Fund for Distinguished Young Scholars of China(31925031)+1 种基金Doctoral Scientific Research Foundation of Liaoning Province(2020-BS-211)Liaoning Province Education Administration(J2020101)。
文摘Cellular senescence is the results of aging and age-related diseases,and the development of anti-aging methods may improve health and extend longevity.The natural flavonol fisetin has been shown to antagonize senescence in vitro and increases longevity in vivo,but has poor water solubility and limited bioavailability.In this study,a food-grade and senescent cell-targeted delivery system for fisetin was developed based on whey protein isolate-galactooligosaccharides(WPI-GOS)Maillard conjugate,which could recognize senescence associatedβ-galactosidase in senescent cells.The fisetin nanoparticles possessed a high encapsulation efficiency,excellent dispersibility in water,good storage stability and well biocompatibility.Moreover,they could effectively accumulate and retain in senescent cells with excellent senescent cell-targeting efficacy,and inhibit the oxidative stress-induced cellular senescence in vitro.Thus,this novel nanoparticle system based on WPI-GOS Maillard conjugate showed promise to deliver hydrophobic bioactive ingredients like fisetin to senescent cells to improve their bioavailability and anti-senescence effect.
