GPT3模型计算中国大陆对流层天顶延迟精度分析

为了评估GPT3模型计算中国大陆对流层延迟改正的精度和可靠性,利用2017-2018年欧洲中期天气预报中心的ERA-Interim大气廓线资料和中国地震局提供的陆态网对对流层延迟产品进行了对比验证分析。结果表明,在中国大陆,GPT3-ZTD模型值的年均偏差(Bias)小于0.6 cm,均方根误差(RMSE)优于3.53 cm。ZTD模型值的精度总体呈现出从中国西北(RMSE3 cm)到东南地区(RMSE5 cm)逐渐降低的趋势;在中国东南地区,GPT3模型低估了对流层天顶延迟,其量级处于-2.0～0.5 cm。ZTD模型值的精度与测站高程呈非线性相关,随着高程增加而精度不断提升。此外,GPT3-ZTD的精度具有明显季节性变化,RMSE基本维持在1～6 cm,ZTD模型值精度的季节性变化与大气中水气含量和变化剧烈程度相关。GPT3模型对中国大陆的对流层天顶延迟计算有较好的精度和可靠性,可为中国大陆对流层延迟改正建模提供一定参考。     

一种对流层散射通信斜延迟估计方法

为实现对流层散射通信的实时性，针对散射通信延迟估计问题，提出了一种不事先进行信道测量的对流层通信延迟计算方法。首先利用全球压力和温度2（GPT2）模型计算气象数据，然后采用射线描迹法对大气层分层并积分求和，最后计算出对流层散射通信延迟。采用与射线描迹法相结合的方法，摆脱了射线描迹法对探空数据的依赖。最后选取我国三个典型测量站数据进行算例分析，计算结果与我国对流层延迟实际分布特征相吻合，为研究在不事先进行信道测量的情况下计算对流层散射通信延迟量提供了一种新思路。     

海峡两岸境外团体套装旅游趋势研究

团体套装旅游是亚洲许多国家及地区的主要海外旅游形式,本研究探索性地研究了海峡两岸境外团体套装旅游的现状和发展趋势,研究方法通过对台湾(台北)与大陆(北京)两地共30家经营境外团体套装旅游的旅行社高级管理者进行深度访谈后,通过分析得到419项类别目(台湾214项;大陆205项),归类过程信度值均超过0.8.研究结果表明,第一,海峡两岸的境外团体套装旅游发展具有相似性;第二,海峡两岸旅行社将朝"大者恒大、小者转型"的方向发展;第三,海峡两岸团体套装旅游产品的包装及营销手段将更趋向消费者导向;第四,在定价趋势上,大陆将朝"参考同业定价"与"需求导向"发展,台湾将以"低价竞争"发展,等等.本研究结果从应用价值上,可为海峡两岸经营境外团体套装的旅游管理者提供重要参考,从理论价值上,可为后续的深入研究提供系统性市场调查与分析结果.     

Quality Selection Criteria of Travel Intermediaries

ABSTRACT

The study explores the selection criteria conducted by travel agencies, evaluating travel intermediaries (destination tour operator) founded on the visionary perspectives of product managers and front-line employees (tour leaders) of Taiwanese travel agencies. Statistically, data accumulated from the 36 product managers and 36 tour leaders by the critical incident technique indicates that local coaches, drivers, and local guides are monumental on group package tour (GPT) service sectors. Meanwhile, another critical issue being scrutinized is the selection scenarios, as to which prices are exponentially executed by product managers, whereas tour leaders tend to be destination tour operator qualities-oriented fundamentally. In order to enhance the destination tour operator service qualities, the research conducts relatively objective selection criteria in selecting the well-qualified and appropriate travel intermediaries as commissioners on the cutting edge travel agencies domain. More substantially, the revealed scenarios of destination tour operators supply the populously rivalous market, China, a relatively credential reference on selecting the well-suited Travel Intermediaries.     

氢能技术作为一般目的技术的研究与分析

通过对一般目的技术概念的分析,阐述了氢能技术具备成为一般目的技术的3个潜在特征：使用普遍性特征、技术动力性特征和创新催生性特征。能源安全、空气污染和全球气候变化等问题的存在,促使氢能技术将在能源体系中得到普遍应用。分析了随着氢能占总能源份额的提高,石油供需格局将发生的变化;阐述了可再生氢能源技术在降低制氢成本方面具有的优势和储氢技术对氢能利用走向实用化、规模化的关键作用,并提出应参考已有一般目的技术对经济增长作用的计算,引入了生态成本计算氢能技术对增长的促进作用。     

Changing Productive Relations,Linkage Effects,and Industrialization

This paper develops a multi-sector endogenous innovation model that is able to take changing productive relations among sectors into account. It is shown that while productivity and demand shocks do not induce any changes in productive relations and linkage effects, shocks in the productivity of R&D increase both backward and forward linkages. Key sectors are characterized as having high forward and backward linkages, which are consistent with the definition of key sectors in the existing empirical studies. However, vertical specialization generates not only sectors with high backward and low forward linkages, but also sectors with low backward and high forward linkages. As a consequence of this vertical specialization, the latter sectors become key sectors, in the sense that they have significant effects on business fluctuations. This implies that general-purpose technology sectors emerge, and sector-specific policies for these sectors play a critical role in economic development and growth.     

公司团体套装旅游的影响因素研究——以中国台湾为例

本研究以中国台湾为例,在市场抽样调查的基础上,对公司团体套装旅游的影响因素进行定性分析,并建立定性分析模型.本研究采用半结构式问卷,结合深入访谈法,对台湾的30家高科技公司(其中21家上市公司),进行了深入访谈.经过严谨的分类过程,从5个题项(旅游信息渠道、目的地、行程、餐宿、景点)中产生29个类别.本研究结果表明,"目的地"、"行程"及"景点"是公司规划团体套装旅游时最主要的影响因素.