City Size,Commuting Cost and Household Savings Rate:Evidence from China

Economics literature has long overlooked an important economic phenomenon:Residents in large cities tend to save a smaller percentage of their disposable income than their peers in small and medium-sized cities.As an explanation for this phenomenon,this paper puts forth the hypothesis that:Residents in large cities purchase more services to increase their leisure time,which is reduced by longer commuting time than in small and medium-sized cities,thus lowering their household savings rate.We conducted an empirical study using panel data of China’s prefecture-level cities and urban household survey data,and employed an instrumental variable to address the endogeneity problem.The result confirmed the accuracy of the above hypothesis.In identifying the economic phenomenon and putting forth the hypothesis,this paper(i)creates a theoretical link between city size and household savings rate,which helps unravel the determinants of the urban household savings rate;(2)provides important implications for China’s policy-making on domestic consumption,urban populations,and industrial development.Priority should be given to developing large and medium-sized cities given the positive effects on domestic consumption and service sector development,and migrant labor shall not be barred from entering large and medium-sized cities to provide services to local residents.

Modelling Recycling Targets:Achieving a 50%Recycling Rate for Household Waste in Denmark

Within the European Union (EU) a paradigm shift is currently occurring in the waste sector, where EU waste directives and national waste strategies are placing emphasis on resource efficiency and recycling targets. The most recent Danish resource strategy calculates a national recycling rate of 22% for household waste, and sets an ambitious goal of a 50% recycling rate by 2020. This study integrates the recycling target into the FRIDA model to project how much waste and from which streams should be diverted from incineration to recycling in order to achieve the target. Furthermore, it discusses how the existing technological, organizational and legislative frameworks may affect recycling activities. The results of the analysis show that with current best practice recycling rates, the 50% recycling rate cannot be reached without recycling of household biowaste. It also shows that all Danish municipalities will need to make efforts to recover all recyclable fractions, and that the increased recycling efforts of only selected municipalities will not be sufficient to reach the target.

基于Householder-QR分解的低复杂度天线选择算法

对多天线空分复用系统中以符号误码率为准则的天线选择算法进行了深入分析,针对以往传统天线选择算法对所有天线子集搜索计算复杂度高的问题,提出了基于复域Householder-QR分解的天线选择算法.所提算法深入分析了线性接收机接收端信噪比与系统信道矩阵之间的关系,利用接收端信噪比近似边界值得到了低复杂度的选择方案,该算法不仅有效地降低了计算复杂度,同时误码率性能与以往算法相近,提高了空分复用系统的传输可靠性,适用于实际相关信道传播环境.仿真实验表明,与传统算法相比该算法具有良好的性能.

基于Householder变换的快速天线选择算法

基于符号误码率准则的天线选择技术可以有效地提高空分复用系统的传输性能,降低系统成本。但同时其对算法的实时性、快速性提出了更高的要求。以往天线选择算法通过奇异值分解来得到天线子集次最优解,计算量大、计算复杂度高。针对这一问题,对空分复用系统的信噪比边界特性进行了深入分析,提出了基于递推Householder-QR分解的天线选择算法。与传统算法相比,该算法降低了计算量的同时提高了系统的传输可靠性,改善了空分复用系统的性能。仿真结果表明:该算法具有良好的性能,并适用于实际相关信道传播环境。

家用泳池光储热柔系统优化方案分析

针对上海地区典型气象年数据及用电负荷数据,对用于家庭泳池的光储热柔系统进行优化选型,提出接入循环水泵柔性调度以及家庭负载的优化控制方案,对系统全年运行的节能效果和经济性展开分析。结果表明:增加光伏板装机容量和蓄电池容量均可以提高能源自给率,且光伏板装机容量的贡献度高于蓄电池容量的。对于一个配置2.7kW光伏板和5kW·h蓄电池的典型泳池的光储热柔系统,光伏发电仅供泳池负载时,循环水泵的优化调度后投资回收期可缩短6个月;对于光伏发电既供泳池负载也用于家庭负载时,循环水泵的优化调度后投资回收期可缩短2个月;引入家庭负载和循环水泵优化调度两种技术,可以将投资回收期缩短近1年。蓄电池单价在100元/千瓦时、光伏板单价在1.4元/瓦以下时,通过加大蓄电池和光伏板容量配置可获得更好的经济性。

Characterization of Household Solid Waste and Management in Tripoli City—Libya

Waste stream characteristics must be understood to tackle waste management problem in Tripoli city, Libya. It is recognized that information on both quantity and composition of generation waste is important for the effective planning of household waste handling infrastructure. So, this study is aimed to evaluating the generation, composition and density of household solid waste in Tripoli city, Libya. The study is carried out according to the Annex 2.1 of: WHO 1996. It was conducted during one week in summer, autumn and winter 2011/2012. The daily household solid waste generation assessment has been carried out for 150 Libyan families where 947 people in three main parts of Tripoli city have been chosen randomly. A questionnaire was prepared according to Buenrostro et al. 2001 and Raje et al. 2001 using door-to-door surveying. The result showed that the average of total generation quantity, daily generation rate, total volume and density were 1415 kg, 0.64 kg/person/day, 19.3 m3 and 74.4 kg/m3 respectively in Tripoli city. Household solid waste contains 36.3% organic matter and 32.5% recyclable materials (glass, paper, plastic, metals). The total generation quantity, daily generation rate, total volume and density were in Tripoli city agreed with those for African and Arabic countries. But the problem is that Tripoli suffers from insufficient municipal solid waste management and lack of sanitary landfills.

Household Solid Waste Generation and Composition: A Case Study in Palapye, Botswana

The purpose of this case study was to conduct a case study in the generation rate, composition, and characterise solid wastes from low, middle and high income households during weekdays and weekends in Palapye, Botswana. The study was conducted through sampling and analysis of the wastes from sampled households from each of the three categories. Palapye village does not have an engineered solid waste management system in place;hence the study can be used as a starting point. The village is rapidly urbanising with many shopping complexes coming up which will generate high amounts of solid wastes of different compositions. The lowest generation rate was 0.038 kg/capita/day from low income households during weekends and the highest was 0.364 kg/capita/day generated from high income households during weekends. The composition of the wastes was dominated by food wastes ranging from 46.44% to 80.78% with low income households generating the highest percentage during weekdays. The average moisture contents of samples from low, middle and high income households were 71% ± 0.0%, 66.3% ± 1.25% and 74.3% ± 2.2% respectively during weekdays compared to 77% ± 0.0%, 66.5% ± 3.5% and 69.3% ± 3.3% during weekends. The average moisture contents from low, middle and high income households were 71% ± 0.0%, 66.3% ± 1.25% and 74.3% ± 2.2% respectively during weekdays compared to 77% ± 0.0%, 66.5% ± 3.5% and 69.3% ± 3.3% during weekends. The results can be used as part of the waste management planning purpose by the Administrative Council of the area.

Impact of Demographic Transition on Household Energy Consumption: A Case from China

Understanding how aging population and low fertility affect household energy consumption is important for optimizing household energy consumption and reaching effective policies.This paper studies the impacts of demographic transition on household energy consumption based on panel data of 30 provinces in China from 2005 to 2016.Child-age dependency rate(CDR)and old-age dependency rate(ODR)are selected to track the shifts in age structure.They are introduced into a STIRPAT model to measure their impacts on household energy consumption.Besides,8 representative regions are additionally chosen and investigated to find some regional characteristics.The results show that current demographic transition to aging population expands household energy consumption.The aging population and low fertility cause additional challenges for energy saving and emission reduction.Household energy consumption in less developed areas is more likely to be affected by CDR and ODR.Regions with large population are also more easily influenced by demographic transitions especially CDR.This study emphases the effects of demographic elements on household energy consumption.It indicates that continuous optimization of household energy consumption structures should be based on population dynamics.

China’s High Savings Rate Puzzle:Role of Precautionary Saving

Academics have yet to agree on the effectiveness of the precautionary saving theory in explaining Chinese households’saving behavior.With the Wenchuan megaearthquake of 2008 as an uncertain event to overcome the endogeneity problem of income volatility,this paper puts forward a brand-new hypothesis that"an earthquake influences household saving rate through its effects on expected income and the variance of expected income."Then,we employ propensity score matching-difference-in-differences(PSMDID)method,the systematic GMM methods,the synthetic control method,together with instrumental variable method,for an analysis of Chinese Household Income Project(CHIP)and inter-provincial data at the micro and macro levels,respectively.We find that the Wenchuan mega-earthquake was followed by an increase in the variance of household expected income in Sichuan and a significant rise in the household saving rate.Second,social protection is negatively correlated with expected income,and has a significant substitutive relationship with saving rate.This finding indirectly proves that the earthquake’s impact on the household saving rate is subject to the variance of expected income,shedding light on how the precautionary saving motivation works in the real world.

农村成长经历会影响城镇家庭储蓄率吗?——来自CHFS 2019的经验证据

由于城市与农村的经济金融环境存在显著差异,成年前在农村成长的城镇居民比在城市成长的城镇居民具有较高的风险厌恶程度和较低的金融知识水平,从而更加偏向低消费和高储蓄。采用中国家庭金融调查(CHFS)2019年数据,将“目前居住在城市地区且拥有非农业户口、18岁之前为农业户口”作为“拥有农村成长经历”的界定标准,实证检验城镇家庭户主的农村成长经历对其家庭储蓄率的影响,结果表明:户主拥有农村成长经历的城镇家庭比户主没有农村成长经历的城镇家庭有更高的储蓄率,风险态度和金融素养在其中发挥了中介作用,即拥有农村成长经历的户主会因较高的风险厌恶程度和较低的金融知识水平而导致其家庭储蓄率较高;农村成长经历对储蓄率的正向影响在户主受教育水平较高、家庭资产较少、经济发展水平较低地区(中西部地区)的家庭中更为显著。因此,需要从改善城市的经济金融状况(降低生活成本、增强社会保障、减少不确定性等)入手来释放城镇居民的消费需求,并通过改善风险态度、加强金融教育、缩小城乡差距等渠道来降低农村成长经历对城镇家庭储蓄率的正向影响。

城乡基本医疗保险制度实施对家庭消费的影响效应及作用机制

基于1988—2018年中国家庭收入调查数据,以城乡基本医疗保险制度实施为准自然实验,采用双重差分法考察了城镇基本医疗保险与新型农村合作医疗保险(即新农合)对家庭消费率的影响及其机制。结果显示:相较于未参保家庭,参加城镇医保的家庭消费率显著高出1.01%,但新农合的影响不显著;机制分析发现,城镇医保促进了参保家庭的总消费和分项消费支出,但新农合对消费支出无显著影响,同时,城镇医保和新农合对总收入和大部分分项收入无显著影响,这与基准回归结果一致;异质性分析表明,城镇医保更多地提升了中老年、非富裕、不健康群体,以及西部地区的家庭消费率。对此,应当充分发挥基本医疗保险制度对提振家庭消费率的积极作用,对“大水漫灌”式的财政补助应进行反思;改变基本医保“户保分离”“业保分离”的现状;加强针对特定人群的医保政策;注重提高参保青年和健康群体的获得感。

不同载畜率水平家庭牧场草畜能量平衡及效益分析

草畜平衡是调节草原牧区生产生态有序发展的有效方式,而进行草畜能量平衡的研究对于家庭牧场尺度上的草畜供求关系与经济效益的提升具有重要作用。本研究基于内蒙古自治区正蓝旗59户家庭牧场的调研数据,以载畜率现状划分不同载畜率梯度并分别构建典型牧户,利用草畜能量平衡模型模拟草畜能量年度供需关系并规划合理经营方案,通过主成分分析确定影响家庭牧场收益的因素。结果表明:调研区家庭牧场随载畜率的增加饲草料支出增加,其中高载畜率牧场比低载畜率牧场的年饲料支出平均高11.75万元;从家畜经济效益角度,低载畜牧场的单位家畜净收益最高,为1075.82元·SE^(−1)·a^(−1),显著高于中载畜率与高载畜率牧场(P<0.05);家畜能量供需整体在年度内呈不均衡状态,冬春季草地能量亏缺最高可达10.61 MJ·SE^(−1)·d^(−1),夏秋季草地满足能量供应且有富余;天然草地面积与家畜数量对不同载畜率下家庭牧场的收益均呈现显著影响。通过降低家畜数量和改变饲喂组合等方式综合提升家畜个体生产性能,对于促进家庭牧场的可持续发展和生态经济双赢具有重要意义。

美联储加息冲击对中国房地产市场的溢出效应及其应对

利用2007—2022年季度数据构建BVAR模型,研究美联储加息对中国房地产市场的外溢效应,发现美联储加息将导致家庭债务、商品房销售额、房价和房地产投资下降,产生负向外溢效应。而后构建含有GHH效用函数、异质性家庭、信贷约束和房地产部门的小国开放经济DSGE模型,在加息冲击下,DSGE模型能够较好地拟合BVAR模型的特征事实。机制分析表明利息差渠道、国际资本流动渠道和利率渠道是其中主要的内在影响机制,信贷约束具有放大机制。反事实实验表明当美联储加息时,中国加息将使房地产市场进一步恶化;中国采取降息或放松信贷政策的逆向操作,在一定程度上能够对冲美联储加息的负面影响,但加剧了资本外流。中国在短期采取降息、在中长期采取加息和放松信贷相结合的政策组合,能够达到更好的政策调控效果。

基于场景交互理论的家用胎心仪功能设计研究

通过“场景交互理论”分析家用胎心仪居家使用的环境适应性问题,对家用胎心仪的功能进行设计优化,提升双人监测的操作体验。基于场景交互理论内涵,将居家胎心监测语境下的角色识别细分为核心用户、辅助用户和周边用户,通过角色行为描述,发掘交互摩擦点,得出初级需求指标,通过AHP层级分析法计算,获取重要设计要求,最终从软硬件交互场景中系统性构建家用胎心仪的产品设计方案,为类似家用医疗产品的设计与开发提供借鉴。

生活垃圾焚烧飞灰烧结处理技术研究

飞灰处理是生活垃圾焚烧处理工艺中必不可少的环节,现行技术在实际应用中飞灰重金属浸出率较低,处理速率较慢,无法达到预期的处理效果,为此提出生活垃圾焚烧飞灰烧结处理技术。通过对飞灰酸消解,去除飞灰中可溶性盐污染物,应用小型圆盘式造球机将飞灰制造成直径10 mm的球团,利用烧结炉对飞灰球团烧结,完成生活垃圾焚烧飞灰烧结处理。试验证明:设计技术飞灰重金属浸出率不低于90%,处理速率可为2 t/h以上,在生活垃圾焚烧飞灰处理方面具有良好的应用前景。

养老保险和医疗保险对城镇家庭消费的影响研究

本文利用2002-2009年广东省城镇住户调查数据(UHS),分析了社会保险参与率和缴费率对城镇家庭消费的影响。借助工具变量法解决模型内生性问题,研究发现:与未参保家庭相比,参保家庭的消费支出将增加0.61%,但社保缴费率增加1%,城镇家庭消费会降低0.63%。从家庭类型看,国有部门、高收入和年轻家庭社保缴费率对消费的抑制效应高于非国有部门、低收入和老年家庭。从社保类型看,养老保险缴费率增加1%,消费将降低2.58%;而医疗保险缴费率增加1%,消费将增加2.1%。从支出类型看,养老保险缴费率对食品、衣服、教育、娱乐和交通等支出大类均具有显著抑制作用,但养老保险缴费率对子女培训班、烟酒和在外就餐等支出细项却具有显著促进作用。

1990年以来中国居民消费率变动的实证分析

20世纪90年代以来中国的居民消费率从总体上呈现出下降的趋势。与国际比较,中国居民消费率严重偏低。中国居民消费率的下降是经济和非经济等多种因素共同作用的结果。居民消费率的持续下降对中国经济与社会的发展都是十分不利的。政府应该通过实施一系列有效的鼓励居民消费的政策措施,逐步改善居民消费率偏低的状况,从而促进国民经济快速、健康、持续地发展。

人口老龄化、养老保险与居民储蓄率

本文首先构建了人口老龄化条件下包含中国现收现付模式与个人账户模式相结合的社会保险制度的OLG模型,并利用2001-2014年的省级面板数据进行实证研究。结果表明,人口老龄化和养老保险对居民储蓄的影响是显著的。随着我国老龄化程度的加剧,老年人口比例上升,将导致储蓄率的下降。同时,社会统筹模式的养老保险将较大程度的挤占消费,原因是当前我国的养老保险还不够健全,并不能提供很好的保障,人们即使缴纳了养老保险仍然缺少安全感。最后本文提出了灵活延迟退休、完善养老保险制度等对策建议。

水力负荷和气温对生态滤池处理农户灰水的影响

在三峡库区一个农户家构建了一套处理单个农户灰水的生态滤池工艺,研究了水力负荷和气温对工艺系统运行效率的影响。结果表明,在0.05~0.4 m3·m-2·d-1的变化范围内,随着水力负荷的逐渐升高,工艺系统对CODCr、NH+4-N、TN、浊度(T)的去除率均呈现逐渐降低的整体变化趋势,而TP的去除率则表现出先升高后降低的变化规律。数据分析表明,生态滤池工艺的最佳运行水力负荷约为0.2 m3·m-2·d-1,在该水力负荷条件下,工艺系统对农户灰水中CODCr、TN、NH+4-N、TP和浊度的平均去除率分别为75%、58%、72%、50%、80%。工艺系统对灰水中各污染物的去除率平均值均表现为夏季高于冬季,且其在冬季对各项指标的去除率仍然较高。在所监测的各项指标中,气温对CODCr指标的系统去除率影响相对最大。

城镇化、人口年龄结构与居民消费——基于省际动态面板的实证研究

伴随改革开放30多年来的经济增长,我国的城镇化进程不断加快、人口年龄结构也在悄然发生变化,然居民消费率却不断下降。文章基于中国29个省份1989-2010年的面板数据,对城镇化、人口年龄结构这些人口消费环境或制度变量与居民消费之间的关系进行了实证研究。使用动态面板一步系统GMM估计发现:城镇化水平与我国居民消费率呈正向关系,城镇化水平每提高1%,居民消费率就增加0.04%,城镇化通过提升居民消费能力、改变居民消费习惯和扩展消费领域等途径间接地提高了总体消费水平,预计这一正向作用还会增强;生命周期理论在我国部分成立,少儿抚养比的下降降低了我国居民消费率,人口老龄化的加速也阻碍了我国居民消费率的提升,因而我国人口年龄结构的变迁是居民消费率下降的原因之一;总的来看,样本期城镇化对居民消费率的正向作用被人口年龄结构的负向作用所抵消,加之中国居民存在消费惰性,这些都有助于解释消费率的持续下降。基于此,本文还就如何扩大内需提出了几点建议。