Interference Cancellation Based Neural Receiver for Superimposed Pilot in Multi-Layer Transmission

In this paper,an interference cancellation based neural receiver for superimposed pilot(SIP)in multi-layer transmission is proposed,where the data and pilot are non-orthogonally superimposed in the same time-frequency resource.Specifically,to deal with the intra-layer and inter-layer interference of SIP under multi-layer transmission,the interference cancellation with superimposed symbol aided channel estimation is leveraged in the neural receiver,accompanied by the pre-design of pilot code-division orthogonal mechanism at transmitter.In addition,to address the complexity issue for inter-vendor collaboration and the generalization problem in practical deployments,respectively,this paper also provides a fixed SIP(F-SIP)design based on constant pilot power ratio and scalable mechanisms for different modulation and coding schemes(MCSs)and transmission layers.Simulation results demonstrate the superiority of the proposed schemes on the performance of block error rate and throughput compared with existing counterparts.

The"4+4"Medical Doctor(MD)Pilot Program at PUMC:Implementation,Performance,and Prospects

Peking Union Medical College(PUMC)launched the"4+4"Medical Doctor(MD)pilot program in 2018,admitting students with non-medical backgrounds from top universities,aligning with national medical talent training policies to foster diverse and eager learners in medicine.On the occasion of the graduation of the first class of the"4+4"MD pilot class at PUMC in 2023,we reviewed the teaching reform in the pilot program and carried out a systematic survey and interviews with students,faculties,and management staff of the pilot class.This article reports on the measures taken by the pilot class at PUMC in enrollment and curriculum setting,and demonstrates the achievements of the pilot class in terms of student academic background structure,knowledge acquisition and skill learning,scientific research ability,and course evaluation.The results indicated that the pilot class had met the national demand for the"Medicine+X"talent training model.More specifically,with a diverse academic backgrounds,the pilot class graduates had academic levels comparable to the eight-year medical education graduates,and their scientific research abilities were satisfactory.The pilot program at PUMC will optimize the curriculum setting,strengthen the construction of faculty,learning resources,and teaching facilities,and reform the academic evaluation methods,thus deepening the reform of medical education and improving the"4+4"MD program as a novel medical education model.

Adverse Pregnancy Outcomes Following Cryotherapy, Thermal Ablation and Loop Electrosurgical Excision Procedure for Cervical Intraepithelial Neoplasia Treatment: A Pilot Study among Zambian Women

Background: Cervical Intraepithelial neoplasia treatments have become essential interventions to manage cervical lesions. Majority of the recipients of these treatments are women within the reproductive age group, who according to literature may be at risk of adverse pregnancy outcomes. This pilot study is part of a study investigating adverse pregnancy outcomes among women who received Cryotherapy, Thermal ablation and Loop Electrosurgical Excision Procedure compared to the untreated women in Zambia. Materials and Methods: This descriptive study analyzed records of 886 (n = 443 treated and n = 443 untreated) women aged 15 - 49 years. The women were either screened with Visual Inspection with Acetic Acid or treated for Cervical Intraepithelial neoplasia at the Adult Infectious Disease Centre between January 2010 and December 2020. Women meeting the criteria were identified using the Visual Inspection with Acetic Acid screening records and telephone interviews to obtain the adverse pregnancy outcome experienced. Data were analysed using STATA version 16 to determine the prevalence and obtain frequency distribution of outcomes of interest. Univariate and multivariable binary logistic regression estimated odds of adverse pregnancy outcomes across the three treatments. Results: The respondents were aged 15 to 49 years. Adverse pregnancy outcomes were observed to be more prevalent in the treatment group (18.5%) compared to the untreated group (5.4%). Normal pregnancy outcomes were lower in the treated (46.3%;n = 443) than the untreated (53.7%;n = 443). The treated group accounted for the majority of abortions (85.2%), prolonged labour (85.7%) and low birth weight (80%), whereas, the untreated accounted for the majority of still births (72.7%). Women treated with cryotherapy (aOR = 2.43, 95% CI = 1.32 - 4.49, p = 0.004), thermal ablation (aOR = 6.37, 95% CI = 0.99 - 41.2, p = 0.052) and Loop Electrosurgical Excision Procedure (aOR = 9.67, 95% CI = 2.17 - 43.1, p = 0.003) had two-, six- and ten-times higher odds of adverse pregnancy outcomes respectively, relative to women who required no treatment. Conclusion: Adverse pregnancy outcomes are prevalent among women who have received treatment in Zambia. The findings indicate that treating Cervical Intraepithelial Neoplasia has been linked to higher chances of experiencing abortion, delivering low birth weight babies and enduring prolonged labor that may result in a caesarean section delivery. Cervical neoplasia treatments, particularly Loop Electrosurgical Excision Procedure, are associated with significantly increased odds of adverse pregnancy outcomes. It is essential to include information about prior Cervical Intraepithelial neoplasia treatment outcomes in obstetric care.

Exploration of Operation and Maintenance Management Mode and Innovation Mechanism of Pilot Base of Chemical Park

Based on the current situation of the operation and maintenance management of the pilot base in many chemical parks in China,this paper conducts an in-depth exploration of the operation and maintenance management and innovation mode of the pilot base from the aspects of the evaluation of the pilot project entering the park,safety and environmental protection supervision,pilot mode,and industrialization mode of the pilot test results,so as to provide solutions for accelerating the process and industrialization of the pilot project and realizing the innovation value of the pilot base.

An analytical framework for the incorporation of non-orthogonal pilots in massive MIMO systems

Training-based cellular communication systems use orthogonal pilot sequences to limit pilot contamination.However,the orthogonality constraint imposes a certain pilot length,and therefore,in communication systems with a large number of users,time-frequency resources are wasted significantly in the training phase.In cellular massive MIMO systems,the time-frequency resources can be used more efficiently by replacing the orthogonal pilots with shorter non-orthogonal pilot sequences in such a way that more space is available for the transmission of additional data symbols,and thus achieving higher data rates.Of course,the use of non-orthogonal pilots introduces additional pilot contamination,so the performance improvement could be achieved under certain system conditions,which are thoroughly investigated in this paper.We first provide a performance analysis framework for the uplink of cellular massive MIMO systems in which the effect of user pilot non-orthogonality has been analytically modelled.In this framework,we derive analytical expressions for the channel estimation,user Signal-to-Interference-plus-Noise-Ratio(SINR),and the average channel capacity per cell.We then use the proposed framework to evaluate the achievable spectral efficiency gain obtained by replacing orthogonal pilots with non-orthogonal counterparts.In particular,the existing trade-off between pilot lengths and the additional data symbols that can be transmitted by reducing the number of pilot symbols,is numerically quantified over a wide range of system parameters.

Optimization of Enzymatic Extraction Process of Polysaccharides from Pseudostellaria heterophylla Fibrous Roots by Response Surface Methodology and Its Pilot Application

[Objectives]To study and optimize the process conditions of enzymatic hydrolysis technology for extracting polysaccharides from Pseudostellaria heterophylla fibrous roots and its application in workshop pilot tests.[Methods]P.heterophylla fibrous roots were taken as the matrix material,and Box Behnken design was used to analyze the extraction time,composite enzyme addition amount,and liquid-solid ratio for response surface optimization experiments,and then applied to the pilot extraction of P.heterophylla fibrous roots.[Results]Response surface analysis showed that all factors had a significant impact on the experimental indicators.The optimal extraction process conditions for polysaccharides from P.heterophylla fibrous roots were extraction time of 2.7 h,compound enzyme addition of 2.5%,and liquid-solid ratio of 32.The yield of polysaccharides from P.heterophylla fibrous roots was 4.83%.The water extraction process of P.heterophylla fibrous roots extraction pilot was used as the control group for response surface optimization of the pilot experiment.The optimization results showed that the extraction time was 3 h,the amount of composite enzyme added was 2.5%,and the liquid-solid ratio was 28.The polysaccharide yield was 4.75%,an increase of 4.63%compared to the control group.[Conclusions]This paper could provide feasibility for the innovation of enzy-matic hydrolysis technology for P.heterophylla fibrous roots and its workshop pilot practice application,as well as a reference for the industrial application of its medicinal resources.

The Tenth Anniversary of Free Trade Pilot Zones in China:Fundamental Experiences and Enhancement Strategies

Since the 18th National Congress of the Communist Party of China,the country has established 21 Free Trade Pilot Zones(FTZs),achieving significant pioneering results in reform and opening up and creating a strong demonstrative effect nationwide.The basic experience from a decade of FTZs includes:adhering to the centralized and unified leadership of the CPC Central Committee;combining top-level design with encouragement of grassroots innovation;leveraging the distinct characteristics and strengths of FTZs to form a differentiated development pattern;maintaining the integration of opening up with domestic reforms;using openness to drive reforms;and organically combining openness with national security assurance.Under the current and future new circumstances,China’s FTZs face new challenges and tasks.In accordance with the directives of the 20th National Congress of the Communist Party of China,an enhancement strategy for the FTZs needs to be implemented.This involves the following:First,accurately understanding and responding to the changing situation to create strategic opportunities.Second,shifting paradigms to implement innovation-driven strategies,using the new development pattern concept to guide the reform experiments and construction of the FTZs.Third,granting more autonomy to FTZs for reforms,pursuing progress while maintaining stability,and solidly advancing the reform experiments in the FTZs.Fourth,orderly expanding the opening up of the service sector and cautiously advancing the internationalization of the renminbi.Fifth,promoting innovative development in trade to build a strong trade nation.Sixth,establishing synergy with bilateral FTZs,Belt and Road cooperation,and national diplomatic strategies to enhance the linkage effect.

Hazardous Attitude Factors Influence Risk Perception in General Aviation Pilots

This manuscript presents a research proposal to investigate how hazardous attitudes among general aviation pilots influence pilot performance in aviation accidents. General aviation pilots train to maintain safe flying conditions, but accidents still occur, and human factors figure prominently among the causes of aviation accidents. The levels of hazardous attitudes among pilots may influence the likelihood of engaging in risky flight behaviors that can lead to accidents. This quantitative study aims to determine whether dangerous attitudes impact risk perception in general aviation pilots. The study will focus on two specific hazardous attitudes, “Anti-Authority” and Macho” behaviors. Among the hazardous attitudes identified by the Federal Aviation Administration (FAA), the two attitudes often stand out in accident investigations and pilot narratives. While all hazardous attitudes have inherent dangers, these two attitudes tend to be more frequently cited in accident reports and investigations. Despite rigorous training in safe flying conditions, general aviation accidents still transpire due to human factors. This research hypothesizes that the five attitudes from the hazardous attitude model, particularly Anti-Authority and Macho, significantly shape pilots’ risk perception. The insights from this study would benefit stakeholders, like the Aircraft Owners and Pilots Association (AOPA), Air Safety Institute, and aviation training programs, in creating training modules tailored to reduce such attitudes.

制度创新能否改善企业ESG表现——基于自由贸易试验区设立的准自然实验

本文以2009—2022年中国A股上市公司为样本,实证检验自贸区设立对企业ESG表现的影响。研究发现,设立自贸区有助于改善所在城市企业的ESG表现。作用机制研究表明,自贸区设立通过意愿、资源和行动三个层面作用于企业ESG表现,意愿层面表现为外资持股增加带来了ESG转型的压力,资源层面表现为融资约束缓解带来了开展ESG活动的资金,行动层面表现为企业环保投资水平和绿色创新水平的提升。结合企业内外部环境研究发现,在公司治理水平和地区金融发展水平越低的企业中,自贸区设立对企业ESG表现的正向影响越显著,再次印证了自贸区设立在影响企业ESG表现中发挥了治理效应和资源效应。异质性分析表明,在低层级城市和非国有企业中,自贸区设立对企业ESG表现的促进效应更大。本文的研究不仅加深了对自贸区设立的认识,也为促进ESG发展提供了实践启示。

飞行员校企合作人才培养模式研究

随着中国“十四五”民用航空发展规划的提出,中国航空业引来了飞速发展的时期。但制约民航业发展的一个重要因素是飞行员的短缺,而飞行员短缺的根本原因是培养成本高、培养周期长。本文通过对国内外飞行员培养方式的分析比较,构建飞行员培养成本模型,计算飞行员培养成本,总结国内飞行员校企合作人才培养模式的优势与不足。针对目前飞行员培养环节中存在的多元化需求不足、实践风险问题以及培养过程中高成本问题等,提出相应的对策建议,以期提高飞行员的培养质量,助力中国航空业飞速发展。

多叠加导频OTFS系统低峰均比信道估计

针对现有信道估计方案导致正交时频空间(Orthogonal Time Frequency Space,OTFS)调制系统峰均功率比(Peak-to-Average Power Ratio,PAPR)高或频谱效率(Spectral Efficiency,SE)低的问题,提出一种多叠加导频的低PAPR、高SE信道估计方法。发送端利用时域正交性和离散傅里叶域相位的随机性,在时延多普勒域中嵌入与数据相叠加的5导频符号的导频图案实现低PAPR,提高SE。接收端以数据符号与噪声之和的能量均值为基准,实现导频信号检测,同时根据每个导频的不同位置信息恢复出存在相位旋转的数据信号。基于能量准则,利用多个独立的接收信号进行联合信道估计,以降低数据符号的干扰,并采用消息传递算法进行数据恢复。仿真结果表明,该方法比单叠加导频信道估计的PAPR低,同时较嵌入式导频信道估计的SE提高约14.4%。

中试实验室大型仪器设备使用绩效评价体系建立与实践

如何建立合理有效的大型仪器设备使用绩效评价制度,切实提高高校公共服务平台中仪器设备的使用效率是实验室管理人员开展研究的重要课题。分析当前高校大型仪器设备使用绩效评价存在的主要问题,结合中试设备的特点,提出构建基于中试服务为主的大型仪器设备使用绩效评价体系。实践表明,新的评价体系能较好地提升大型仪器设备的使用效益,也能为同类单位绩效考核提供新思路。

国家信息消费试点政策是否促进了城市数字经济发展?——基于2005—2021年中国292个城市面板数据

数字经济的迅猛崛起,已显著提升了其在国民经济结构中的战略地位,成为一股不可或缺的力量,强有力地推动着我国经济向更高质量层次迈进。本文利用2005—2021年中国292个地级市的面板数据,实证研究了国家信息消费试点政策对数字经济发展的影响。结果发现:国家信息消费试点政策对数字经济发展水平具有正向影响;信息化发展水平是国家信息消费试点政策与数字经济发展水平的中介变量;国家信息消费试点政策对数字经济发展的促进作用在特大型城市与大型城市相对更大。基于此,应制定政策鼓励高校和科研机构加大对数字技术人才的培养力度,不断提升国家信息消费试点政策对西部地区数字经济发展水平的促进作用,鼓励试点地区大力发展数字内容、数字娱乐等产业,为客户提供更真实的信息消费体验。

区域创新改革政策如何影响城市碳排放的“减量增质”?——基于全面创新改革试验区的准自然实验

“双碳”目标既是我国对世界的庄重承诺,也是我国创新驱动发展战略的必然举措。稳妥推进“双碳”目标,需立足我国能源资源禀赋,逐步转向碳排放总量和强度“双控”制度,积极参与全球环境治理。论文以全面创新改革试验区城市为准自然实验,基于中国282个地级市2010—2019年面板数据,采用双重差分法检验试验区对城市碳排放“量”与“质”的影响及其作用机制。研究表明,试验区通过提高城市绿色创新能力以及产业集聚效应显著降低城市碳排放水平并提高城市碳生产率,在老工业基地城市以及非资源型城市效果更明显。结论有助于进一步扩大试验区的设立以推动城市碳减排可持续发展,并为碳减排政策提供进一步的决策参考。

自由贸易试验区经济效应与影响路径分析——以中国(四川)自贸试验区为例

中国(四川)自由贸易试验区作为首批内陆型自贸区之一,自2017年4月揭牌设立以来在完成改革试验任务、制度创新成果推广、开放引领作用、营商环境优化等方面均取得显著成效,并极大地促进了四川地区经济增长。采用合成控制法评估设立四川自贸区的经济效应,并从消费、外商直接投资和进出口贸易三个渠道分析自贸区影响地区经济增长的路径,在此基础上再进行双重差分估计和变换处理组单元与控制组单元的安慰剂检验。实证结果表明,四川自贸区设立对当地经济增长具有显著的正向推动作用,且影响路径是外商直接投资和进出口贸易,相比而言通过提升消费来促进四川地区经济增长的影响统计意义上并不显著。

自贸试验区设立能否提升地区共同富裕水平——基于宏微观数据的双重验证

新时代推进中国式现代化建设,走共同富裕道路,需全面深化改革与扩大高水平对外开放。自贸试验区作为高水平对外开放体系的基础和平台,对促进共同富裕具有重要意义。基于我国2006—2021年276个地级市面板数据及中国家庭追踪调查数据,通过构建多期双重差分模型,实证检验自贸试验区设立对共同富裕的影响。研究发现,自贸试验区设立显著提升了地区共同富裕水平,且经系列检验后结果依然稳健。异质性分析表明,该政策效应在经济基础较好的地区更显著,且效应随自贸试验区成立批次先增后减。机制检验表明,自贸试验区通过产业、贸易和要素三渠道促进共同富裕。通过从自贸试验区设立的视角探究共同富裕水平提升的路径,能够为地区资源统筹与协调发展、促进共同富裕提供政策启示。

市场型环境规制对碳排放强度的影响效应和机制研究——基于碳交易试点政策的经验证据

作为市场型环境规制手段的碳排放权交易是助力实现“双碳”目标的重要政策。基于2009—2019年中国省级面板数据,运用双重差分法,探究碳交易试点政策的实施对碳强度的影响效应和影响机制。研究发现:碳交易试点政策有效降低了试点地区的碳排放强度,发挥了市场型环境规制的积极作用,而且碳交易机制通过影响能源消费量这一渠道遏制了碳排放强度的增长。通过调节效应模型发现,地区产业结构负向调节碳交易试点政策的降碳效应,而政府规模则正向调节碳交易试点政策的降碳效应。以上结论为进一步推动全国性碳交易市场稳健发展、发挥市场型环境规制的积极作用以及推进“双碳”目标实现提供了重要的经验证据。

中国试点碳市场交易价格的影响因素及驱动路径

碳价是碳市场运行的核心问题。厘清碳市场交易价格机制的内在逻辑,是推动形成有效价格信号,充分发挥碳市场资源配置作用和价格发现功能的前提和关键。文章基于中国八个碳交易试点市场的样本数据,重点从需求侧出发,借助“规模-结构-技术”分析框架,运用模糊集定性比较分析方法(fsQCA)对试点碳市场价格的影响机制进行综合研判。研究发现:由于回弹效应的存在,资本投入引致的技术效应可通过规模效应和结构效应影响碳排放,进而影响碳价;在排除资本偏向型技术进步可能带来的碳回弹效应后,较低的经济发展水平和劳动偏向型技术进步是引致碳低价的重要力量;在一定条件下,经济发展水平和能源偏向型技术进步之间存在替代效应,与其他条件共同作用可以引致低水平碳价。

新疆边境旅游高质量发展的路径研究

在中国(新疆)自由贸易试验区(以下简称“新疆自贸试验区”)挂牌成立之际,如何充分发挥出新疆自贸试验区的优势,打造西部边境地区旅游高质量发展的示范样板,赋能旅游产业高质量发展,是目前亟待解决的问题。通过系统梳理新疆边境旅游发展基础和面临的主要困难,提出新疆自贸试验区“先行先试”进一步推进新疆边境旅游高质量发展的有关建议。

智慧城市试点政策对城市碳排放强度的影响及机制分析

本文根据2000—2022年从中国218个城市收集的数据,使用多期模型实证分析了智慧城市试点政策对碳强度的影响,并从理论和实证角度分析了智慧城镇建设对城市碳强度的作用和机制,为未来构建更加完善的智慧城市提供经验指导。实证结果证实了试点政策可以有效降低城市地区的二氧化碳排放强度。同时,鼓励产业结构转型和现代化、促进人才库形式的高素质人才流动、采取适当的环境监管措施是试点城市降低碳减排强度的三种有效方法。此外,试点城市的碳减排强度因地理位置、数字基础设施水平和城市规模不同而有所差异。