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近年来,全球气温都出现了增长的情况,导致海平面出现了上升的情况,同时很多的地区出现了极端的天气情况,很多地区出现了暴雨暴雪的情况,很多的地区出现了干旱的情况,还有些地区出现了生物不能生长的情况。这些情况的出现和气候变暖是有很大关系的,为了对环境变暖问题进行治理,一定要采取必要的措施,进行植树造林,同时也要对环境保护,这样可以改善环境变暖的情况。 相似文献
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近年来国家相继出台相关指导意见,提出开展自然资源资产清查核算,及时掌握资产家底;研究建立自然资源资产核算评价制度,开展实物量统计,探索价值量的核算;从价值和实物等方面,反映国有资产存量情况和变动情况,实现全口径、全覆盖国有资产管理情况报告制度。基于当前政策背景的基础上,文章结合现阶段的工作情况,以南安市的清查试点工作为例,浅谈开展全民所有自然资源资产清查工作的流程和方法,并对过程中遇到的问题及解决思路进行探讨。 相似文献
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据有关媒体报道,不久前在韩国发生了一起飞机失事事件,机上大多数人都不幸遇难,其中一个小孩却得救了。为什么小孩会得救呢?原因是她的母亲在飞机断裂的一瞬间把小孩推出了飞机。再如,母亲和自己的孩子爬山的时候,孩子在爬山路上摔倒的一瞬间,作为母亲会采取什么样的行动呢2一般来讲,会出现以下三种情况:第一种情况是孩子和母亲一起摔下去;第二种情况是母亲和孩子只能一个人得救;第三种情况是两个都能得救。当然,第三种情况是最好的情况,最完美的情况。但是,当这种情况禾出现时,其中比较好的情况是一个人得救,就是上述飞机… 相似文献
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近日,中卫市纪律检查委员会、民政局、农牧局、审计局四部门联合下文,从今年7月至9月期间对各镇(乡)所有负有经济责任的村干部任期履行经济职责情况进行财务清理审计。审计的主要内容是村集体财务收支情况,集体资产管理使用情况,生产经营、建设项目的发包和管理情况,上级划拨或接受社会捐赠的资金和物资使用情况,土地补偿资金分配和使用情况,以及移民搬迁村和并村过程中集体资产的处置情况,村级债权、债务状况。重点关注有无挪用、私分和长期占用集体资金的问题,有无滥用职权非法转让、侵占集体资产的问题,有无存在超标准领取个人报酬或在集体资金中报销个人应负担的费用等行为。 相似文献
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水是地球上一切生物生存的必备条件,随着近年来水利行业的持续发展,GIS的应用更是越来越普遍。本文就地球上的水资源情况以及我国水资源情况进行分析,同时介绍了GIS技术的应用与发展情况,进一步研究GIS技术的深度开发以及其应用水平的提高途径。 相似文献
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这次全省酒类管理工作会议,主要任务是贯彻落实全国和全省流通工作会议精神,总结去年酒类管理工作情况和交流各地开展酒类专项整治活动情况。分析当前面临的新情况、新问题,安排布署今年工作。会上,各地酒办认真总结交流了工作情况,5个单位做了典型发言;福善同志传达了商务部和省有关酒类立法工作进展情况,提出了做好今年酒类管理工作的具体意见,我完全赞同。希望各级酒办要结合当地实际情况,认真组织落实,力争酒类管理工作再上新台阶。 相似文献
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针对330kV秦安变1#主变乙炔超标的现状,通过运行监视和跟踪检测,根据收集到的测试数据分析,该台变压器虽然存在乙炔超标的情况,但由于运行稳定,未出现乙炔含量突变的情况,乙烯含量较高属于正常情况,可以继续运行,但需要加强监视。 相似文献
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在审计过程中,审计人员时常要求被审计单位对某一事项出具“情况说明”,以此为依据发表审计评价意见。关于“情况说明”证明力的讨论由来已久,本文从“情况说明”作为审计证据证明力和审计人员的法定职责等方面进行分析,提出“情况说明”应当慎用的观点,并针对其在取证实践中的不当之处提出了对策建议,对于启发审计人员审慎思考具有一定价值。 相似文献
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提出了一种基于CVaR的投资组合模型,对组合资产收益率不做正态分布假设,用MAD模型作为一个约束条件,实现波动性度量限制,用上凸效用函数作为一个约束条件,表示风险资产交易费用。实验结果表明,该模型满足实际投资要求,符合实际投资规律,与M-V模型和原始CVaR模型相比具有波动性和风险价值最小化的优势。 相似文献
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Anthony Y. C. Kuk 《Revue internationale de statistique》2020,88(3):715-727
A brief survey on methods to handle non-proportional hazards in survival analysis is given with emphasis on short-term and long-term hazard ratio modelling. A drawback of the existing model of this nature is that except at time zero or infinity, the hazard ratio for a unit increase in the value of a covariate depends on the starting value. With two or more covariates, the hazard ratio for a unit increase in one covariate with other covariates held fixed depends in an unintended way on the values of the other covariates. We propose an alternative way to model short-term and long-term hazard ratios without the above drawbacks through a judicious choice of covariate-time interactions. Under the new model, it is easier to describe the time-varying effect of each covariate on the hazard. Nonparametric maximum likelihood estimation for the new model can be carried out in the same way as for the existing model. We also propose a product version of the existing model, which overcomes its second drawback but not the first. The advocated covariate–time interaction model provides a better fit to the Veterans Administration lung cancer data set than the original and product versions of the existing model. 相似文献
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We investigate the economic significance of trading off empirical validity of models against other desirable model properties. Our investigation is based on three alternative econometric systems of the supply side, in a model that can be used to discuss optimal monetary policy in Norway. Our results caution against compromising empirical validity when selecting a model for policy analysis. We also find large costs from basing policies on the robust model, or on a suite of models, even when it contains the valid model. This confirms an important role for econometric modelling and evaluation in model choice for policy analysis. 相似文献
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探寻一个先进的创新管理模式是一个地区开展技术创新活动并取得成功的根本保证。基于孵化器的创新管理模式着重强调的是成立一个孵化联盟组织,它是对产学研合作模式的一个延续,对技术创新的成败至关重要。本文在提出影响技术创新管理模式的五大因素的前提下,重点探讨了该模式的具体实践逻辑,并结合重庆市信息产业具体实际,论证该模式在重庆实施的可能性,对提升信息产业技术创新管理水平给出了对策与建议。 相似文献
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Zhiwei Zhang Shujie Ma Changyu Shen Chunling Liu 《Revue internationale de statistique》2019,87(3):514-530
Mann–Whitney‐type causal effects are generally applicable to outcome variables with a natural ordering, have been recommended for clinical trials because of their clinical relevance and interpretability and are particularly useful in analysing an ordinal composite outcome that combines an original primary outcome with death and possibly treatment discontinuation. In this article, we consider robust and efficient estimation of such causal effects in observational studies and clinical trials. For observational studies, we propose and compare several estimators: regression estimators based on an outcome regression (OR) model or a generalised probabilistic index (GPI) model, an inverse probability weighted estimator based on a propensity score model and two doubly robust (DR), locally efficient estimators. One of the DR estimators involves a propensity score model and an OR model, is consistent and asymptotically normal under the union of the two models and attains the semiparametric information bound when both models are correct. The other DR estimator has the same properties with the OR model replaced by a GPI model. For clinical trials, we extend an existing augmented estimator based on a GPI model and propose a new one based on an OR model. The methods are evaluated and compared in simulation experiments and applied to a clinical trial in cardiology and an observational study in obstetrics. 相似文献
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《International Journal of Forecasting》2019,35(4):1193-1210
This paper introduces a new forecasting model for VIX futures returns. The model is structural in nature and parsimonious, and contains parameters that are relatively easy to estimate. The forecasts of next day VIX futures returns based on this model are superior to those produced by a linear forecasting model that uses the same set of predictors. Moreover, the profits to a market-timing model based on the proposed forecasts are statistically and economically significant, and are robust to both the method used for adjusting for risk and transaction costs (up to around 15 basis points). In contrast, the forecasts generated by the linear forecasting model are not. 相似文献
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《International Journal of Forecasting》2023,39(3):1303-1317
The well-developed ETS (ExponenTial Smoothing, or Error, Trend, Seasonality) method incorporates a family of exponential smoothing models in state space representation and is widely used for automatic forecasting. The existing ETS method uses information criteria for model selection by choosing an optimal model with the smallest information criterion among all models fitted to a given time series. The ETS method under such a model selection scheme suffers from computational complexity when applied to large-scale time series data. To tackle this issue, we propose an efficient approach to ETS model selection by training classifiers on simulated data to predict appropriate model component forms for a given time series. We provide a simulation study to show the model selection ability of the proposed approach on simulated data. We evaluate our approach on the widely used M4 forecasting competition dataset in terms of both point forecasts and prediction intervals. To demonstrate the practical value of our method, we showcase the performance improvements from our approach on a monthly hospital dataset. 相似文献
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在前人研究的基础上,探讨时间因素在牛鞭效应中的影响。将经典熵模型和时间因素结合起来,创造性地构造了基于牛鞭效应的"时效熵"模型。对模型进行了仿真验证,发现熵模型对应的数据与牛鞭效应的大小具有秩一致性。根据熵模型的标示进行仿真发现:随着订货提前期跨度的拉长,牛鞭效应加剧。 相似文献
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Michael J. Dueker Zacharias Psaradakis Martin Sola Fabio Spagnolo 《Journal of econometrics》2011,160(2):311-325
This paper proposes a contemporaneous-threshold multivariate smooth transition autoregressive (C-MSTAR) model in which the regime weights depend on the ex-ante probabilities that latent regime-specific variables exceed certain threshold values. A key feature of the model is that the transition function depends on all the parameters of the model as well as on the data. Since the mixing weights are also a function of the regime-specific noise covariance matrix, the model can account for contemporaneous regime-specific co-movements of the variables. The stability and distributional properties of the proposed model are discussed, as well as issues of estimation, testing and forecasting. The practical usefulness of the C-MSTAR model is illustrated by examining the relationship between US stock prices and interest rates. 相似文献