In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M...In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M/G/1 queue again. Through establishing and solving the density evolution equa tions, the busy-period distribution, and the stationary distributions of waitin g time and queue length were obtained. In addition, the stability condition of th is queue system was given by means of an imbedded renewal process.展开更多
In wireless sensor networks(WSNs),nodes are often scheduled to alternate between working mode and sleeping mode from energy efficiency point of view.When delay is tolerable,it is not necessary to preserve network conn...In wireless sensor networks(WSNs),nodes are often scheduled to alternate between working mode and sleeping mode from energy efficiency point of view.When delay is tolerable,it is not necessary to preserve network connectivity during activity(working or sleeping) scheduling,enabling more sensors to be switched to sleeping mode and thus more energy savings.In this paper,the nodal behavior in such delay-tolerant WSNs(DT-WSNs) is modeled and analyzed.The maximum hop count with a routing path is derived in order not to violate a given sensor-to-sink delay constraint,along with extensive simulation results.展开更多
This paper presents an analytical model of a cross-layer communication system to enable improvement in the Transmission Control Protocol (TCP) over mixed wired and wireless Internet. The focus is on the quantitative p...This paper presents an analytical model of a cross-layer communication system to enable improvement in the Transmission Control Protocol (TCP) over mixed wired and wireless Internet. The focus is on the quantitative performance evaluation of the interactions between TCP NewReno and a hybrid Automatic Repeat reQuest protocol (HARQ) in the link layer (LL) with a finite buffer size. The significant improvement in TCP NewReno throughput when HARQ adaptively selects its optimal settings according to explicit cross-layer information is shown. Through ns-2 simulations, it is demonstrated that this proposed analytical model accurately predicts the TCP-HARQ system performance.展开更多
Background:Cancer cells selectively promote the translation of oncogenic tran-scripts to stimulate cancer progression.Although growing evidence has revealed that tRNA modifications and related genes participate in thi...Background:Cancer cells selectively promote the translation of oncogenic tran-scripts to stimulate cancer progression.Although growing evidence has revealed that tRNA modifications and related genes participate in this process,their roles in head and neck squamous cell carcinoma(HNSCC)remain largely unchar-acterized.Here,we sought to investigate the function and mechanisms of the transfer RNA(tRNA)N7-methylguanosine(m'G)modification in regulating the occurrence and development of HNSCC.Methods:Cell lost of-function and gain-of function assays,xenograft models,conditional knockout and knockin mouse models were used to study the physi-ological functions of tRNA m'G modification in HNSCC tumorigenesis.tRNA modification and expression profiling,mRNA translation profiling and res-cue assays were performed to uncover the underlying molecular mechanisms.Single-cell RNA sequencing(scRNA seq)was conducted to explore the tumor microenvironment changes.Results:The tRNA.m7G methyltransferase complex components Methyltransferase-like 1(METTL1)/WD repeat domain 4(WDR4)were upregulated in HNSCC and associated with a poor prognosis.Functionally,METTL1/WDR4 promoted HNSCC progression and metastasis in cell-based and transgenic mouse models.Mechanistically,ablation of METTL1 reduced the m'G levels of 16 tRNAS,inhibiting the translation of a subset of oncogenic transcripts,including genes related to the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/AKT/mTOR)signaling pathway.In addition,chemical modulators of the PI3K/Akt/mTOR signaling pathway reversed the effects of Mettll in mouse HNSCC.Furthermore,scRNA-seq results revealed that Mettll knockout in mouse tumor cells altered the immune landscape and cell-cell interaction between the tumor and stromal compartment.Conclusions:The tRNA m?G methyltransferase METTLI was found to promote the development and malignancy of HNSCC through regulating global mRNA translation,including the PI3K/AKT/mTOR signaling pathway,and found to alter immune landscape.METTLI could be a promising treatment target for HNSCC patients.展开更多
In this paper we study a queueing system with state-dependent services and state-dependent vacations, or simply G/M（n）/1/K. Since the service rate is state-dependent, this system includes G/M/c and G/M/c/K queues wi...In this paper we study a queueing system with state-dependent services and state-dependent vacations, or simply G/M（n）/1/K. Since the service rate is state-dependent, this system includes G/M/c and G/M/c/K queues with various types of station vacations as special cases. We provide a recursive algorithm using the supplementary variable technique to numerically compute the stationary queue length distribution of the system. The only input requirement is the Laplace-Stieltjes transform of the interarrival distribution as well as the state-dependent service rate and state-dependent vacation rate. In a subsequent companion paper, we study its dual system M（n）/G/1/K queue with statedependent vacations.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.70171059)
文摘In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M/G/1 queue again. Through establishing and solving the density evolution equa tions, the busy-period distribution, and the stationary distributions of waitin g time and queue length were obtained. In addition, the stability condition of th is queue system was given by means of an imbedded renewal process.
基金Sponsored by the Shanghai Education Bureau(Grant No. 11YZ93,A-3101-10-035)the Shanghai Baiyulan Funding(Grant No. 2010B086)the National Natural Science Foundation of China(Grant No. 61003215)
文摘In wireless sensor networks(WSNs),nodes are often scheduled to alternate between working mode and sleeping mode from energy efficiency point of view.When delay is tolerable,it is not necessary to preserve network connectivity during activity(working or sleeping) scheduling,enabling more sensors to be switched to sleeping mode and thus more energy savings.In this paper,the nodal behavior in such delay-tolerant WSNs(DT-WSNs) is modeled and analyzed.The maximum hop count with a routing path is derived in order not to violate a given sensor-to-sink delay constraint,along with extensive simulation results.
文摘This paper presents an analytical model of a cross-layer communication system to enable improvement in the Transmission Control Protocol (TCP) over mixed wired and wireless Internet. The focus is on the quantitative performance evaluation of the interactions between TCP NewReno and a hybrid Automatic Repeat reQuest protocol (HARQ) in the link layer (LL) with a finite buffer size. The significant improvement in TCP NewReno throughput when HARQ adaptively selects its optimal settings according to explicit cross-layer information is shown. Through ns-2 simulations, it is demonstrated that this proposed analytical model accurately predicts the TCP-HARQ system performance.
基金National Natural Science Foundation of China,Grant/Award Numbers:81872409,82173362Natural Science Foundation of Guangdong Province,Grant/Award Numbers:2018A030313610,2019A1515110110,2020A1515010291+1 种基金The Open Funding of the State Key Laboratory of Oral Diseases,Grant/Award Number:SKLOD2021OF02and the use was approved by the Institutional Review Board of the First Affiliated Hospital of Sun Yat-Sen University(2016074).The nude mouse experi-ments performed were approved by the Laboratory Ani-mal Center of Sun Yat-SenUniversity(SYSU-IACUC-2021-000092).The transgenic mouse experiments performed were approved by the Laboratory Animal Center of Sun Yat-Sen University(SYSU-IACUC-2020-000569).
文摘Background:Cancer cells selectively promote the translation of oncogenic tran-scripts to stimulate cancer progression.Although growing evidence has revealed that tRNA modifications and related genes participate in this process,their roles in head and neck squamous cell carcinoma(HNSCC)remain largely unchar-acterized.Here,we sought to investigate the function and mechanisms of the transfer RNA(tRNA)N7-methylguanosine(m'G)modification in regulating the occurrence and development of HNSCC.Methods:Cell lost of-function and gain-of function assays,xenograft models,conditional knockout and knockin mouse models were used to study the physi-ological functions of tRNA m'G modification in HNSCC tumorigenesis.tRNA modification and expression profiling,mRNA translation profiling and res-cue assays were performed to uncover the underlying molecular mechanisms.Single-cell RNA sequencing(scRNA seq)was conducted to explore the tumor microenvironment changes.Results:The tRNA.m7G methyltransferase complex components Methyltransferase-like 1(METTL1)/WD repeat domain 4(WDR4)were upregulated in HNSCC and associated with a poor prognosis.Functionally,METTL1/WDR4 promoted HNSCC progression and metastasis in cell-based and transgenic mouse models.Mechanistically,ablation of METTL1 reduced the m'G levels of 16 tRNAS,inhibiting the translation of a subset of oncogenic transcripts,including genes related to the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/AKT/mTOR)signaling pathway.In addition,chemical modulators of the PI3K/Akt/mTOR signaling pathway reversed the effects of Mettll in mouse HNSCC.Furthermore,scRNA-seq results revealed that Mettll knockout in mouse tumor cells altered the immune landscape and cell-cell interaction between the tumor and stromal compartment.Conclusions:The tRNA m?G methyltransferase METTLI was found to promote the development and malignancy of HNSCC through regulating global mRNA translation,including the PI3K/AKT/mTOR signaling pathway,and found to alter immune landscape.METTLI could be a promising treatment target for HNSCC patients.
基金supported by National Science Foundation under DMI-0200306supported in part by a grant from National Natural Science Foundation of China under No.70228001.
文摘In this paper we study a queueing system with state-dependent services and state-dependent vacations, or simply G/M（n）/1/K. Since the service rate is state-dependent, this system includes G/M/c and G/M/c/K queues with various types of station vacations as special cases. We provide a recursive algorithm using the supplementary variable technique to numerically compute the stationary queue length distribution of the system. The only input requirement is the Laplace-Stieltjes transform of the interarrival distribution as well as the state-dependent service rate and state-dependent vacation rate. In a subsequent companion paper, we study its dual system M（n）/G/1/K queue with statedependent vacations.
