广义Kac-Moody代数模的权链与权集

广义Kac-Moody代数的概念是由Borcherds首先引入的,普通Kac-Moody代数的许多结果都可推广到其上去(详见文献[1]和[2]中§11.13),本文讨论了广义Kac-Moody代数模L(A)的权链和权集的某些性质.设A=(a_(ij))_(n×n)为一实矩阵且满足(Cl)a_(li)=2或a_(ii)≤0,(C2)a_(ij)≤O,如果i≠j;a_(ij)∈Z,如果a_(ii)=2,(C3)a_(ij)=O当且仅当a_(ji)=0,

SINR模型下链路调度问题的启发式算法

在SINR模型下研究了无线网络中与链路调度密切相关的两个重要的NP-完全问题:最大链路独立集(Maximum Independent Set of Links,MISL)和最大带权链路独立集(Maximum Weighted Independent Set of Links,MWISL),给出了对这两个问题有好的实际性能保障的有效启发式算法,从理论上证明了算法的正确性,并通过仿真验证了算法的有效性。对于MISL问题,在MTIR算法(Yang等人于2010年提出)的基础上,得到了性能更优的启发式算法MTBR;对于MWISL问题给出的有效启发式算法,比近似算法PMWISL(Wan等人于2011年提出)的性能有了较大的提高。

Available parking space occupancy change characteristics and short-term forecasting model

Based on an available parking space occupancy （APSO） survey conducted in Nanjing, China, an APSO forecasting model is proposed. The APSO survey results indicate that the time series of APSO with different time-sections are periodical and self-similar, and the fluctuation of the APSO increases with the decrease in time-sections. Taking the short-time change behavior into account, an APSO forecasting model combined wavelet analysis and a weighted Markov chain is presented. In this model, an original APSO time series is first decomposed by wavelet analysis, and the results include low frequency signals representing the basic trends of APSO and several high frequency signals representing disturbances of the APSO. Then different Markov models are used to forecast the changes of low and high frequency signals, respectively. Finally, integrating the predicted results induces the final forecasted APSO. A case study verifies the applicability of the proposed model. The comparisons between measured and forecasted results show that the model is a competent model and its accuracy relies on real-time update of the APSO database.

Model predictive flux control of permanent magnet synchronous motor driven by three-level inverter based on fine-division strategy

Aiming at the difficulty of setting the weight coefficient in the value function of model predictive torque control(MPTC)for permanent magnet synchronous motor(PMSM)driven by three-level inverter,a fine-division model predictive flux control(MPFC)method is proposed.First,establish a mathematical model between the motor torque and the stator flux linkage according to the mathematical equations of PMSM.Thus,the control of the motor torque and stator flux linkage in the MPTC is transformed into the control of a single stator flux linkage vector,omitting the cumbersome weight setting process in the traditional MPTC.The midpoint potential control strategy is proposed,which uses the characteristics of redundant small vectors to balance the midpoint potential.After that,a fine-division strategy is proposed,which effectively reduces the number of candidate vectors and the computational burden of the system.Finally,the proposed MPFC is compared with MPTC by simulation.The results show that the proposed fine-division MPFC effectively reduces the system calculation,and has the advantages of simple principle and better dynamic and steady-state control performance.The feasibility of the control strategy is verified.

The Project System:A New Form of State Governance

As the incremental component of the new dual track system, the project system aims to use special transfer payments from state finances and other strategies to break the shackles of the existing bureaucratic order, as represented by the work unit system. This approach seeks to curb the polarization arising from marketization and increase investment in people＇s livelihood and public services. The new project-centered system of governance has encouraged the formation of hierarchical central-local governance mechanisms, leading to a number of unforeseen outcomes for grassroots society. Collective debt at the grassroots level, departmental interests and the systemic risk brought about by the project system will have important implications for the sustainable development of society.

Spatio-temporal Dynamic Evolution and the Factors Impacting Eco-efficiency in Chengdu-Chongqing Economic Circle

In response to the 14th National Five-year Plan of China and to better explore new strategies for promoting regional coordinated green development, the eco-efficiency values of Chengdu-Chongqing Economic Circle and the corresponding temporal analysis from 2004 to 2018 were assessed in this paper using the super-SBM model and Markov chain. Meanwhile, the spatial analysis of eco-efficiency was conducted by a geographically weighted regression model. Although eco-efficiency has risen at an increasing rate, the economic development of Chengdu-Chongqing Economic Circle was still ecologically ineffective. This means there is an urgent need to improve the efficiency of resource utilization and promote technological innovation. During the study period, the evolution of the eco-efficiency presented as a “π” shape, and was accompanied by the phenomenon of “club convergence”. There was also a strong tendency for eco-efficiency to maintain the original status quo, which indicates that it lacked sufficient momentum for improvement, so it was difficult to achieve a leapfrog transfer. Spatially, the eco-efficiency was distributed from northwest to southeast in a high-low-high manner. The spatial-temporal differences of eco-efficiency narrowed but the effect of agglomeration was relatively weak and there was a polarization trend. Further investigation suggests that the differences in the development level of urbanization, opening, technology, environmental regulation and advancement of industrial structure led to the spatial differences of eco-efficiency. Each city in the Economic Circle should make every effort to improve eco-efficiency accordingly, and thus to promote the green development of the whole region, so as to lay a foundation for driving the green and coordinated development of the central and western regions.

Transcriptomic analysis reveals key lnc RNAs associated with ribosomal biogenesis and epidermis differentiation in head and neck squamous cell carcinoma

Objective： In this study, we aimed to expand current knowledge of head and neck squamous cell carcinoma （HNSCC）-associated long noncoding RNAs （IncRNAs）, and to discover potential IncRNA prognostic biomarkers for HNSCC based on next-generation RNA-seq. Methods： RNA-seq data of 546 samples from patients with HNSCC were downloaded from The Cancer Genome Atlas （TCGA）, including 43 paired samples of tumor tissue and adjacent normal tissue. An integrated analysis incorporating differential expression, weighted gene co-expression networks, functional enrichment, clinical parameters, and survival analysis was conducted to discover HNSCC-associated IncRNAs. The function of CYTOR was verified by cell-based experiments. To further identify IncRNAs with prognostic significance, a multivariate Cox proportional hazard regression analysis was performed. The identified IncRNAs were validated with an independent cohort using clinical feature relevance analysis and multivariate Cox regression analysis. Results： We identified nine HNSCC-relevant IncRNAs likely to play pivotal roles in HNSCC onset and development. By functional enrichment analysis, we revealed that CYTOR might participate in the multistep pathological processes of cancer, such as ribosome biogenesis and maintenance of genomic stability. CY-I-OR was identified to be positively correlated with lymph node metastasis, and significantly negatively correlated with overall survival （OS） and disease free survival （DFS） of HNSCC patients. Moreover, CYTOR inhibited cell apoptosis following treatment with the chemotherapeutic drug diamminedichloroplatinum （DDP）. HCG22, the most dramatically down-regulated IncRNA in tumor tissue, may function in epidermis differentiation. It was also significantly associated with several clinical features of patients with HNSCC, and positively correlated with patient survival. CYTOR and HCG22 maintained their prognostic values in- dependent of several clinical features in multivariate Cox hazards analysis. Notably, validation either based on an independent HNSCC cohort or by laboratory experiments confirmed these findings. Conclusions： Our transcriptomic analysis suggested that dysregulation of these HNSCC-associated IncRNAs might be involved in HNSCC oncogenesis and progression. Moreover, CYTOR and HCG22 were confirmed as two independent prognostic factors for HNSCC patient survival, providing new insights into the roles of these IncRNAs in HNSCC as well as clinical applications.