Saving,Wealth and the Transition from Transfers to Individual Responsibility: The Cases of Taiwan and the United States*

Under the life‐cycle saving model, population aging leads to an increased demand for life‐cycle wealth. Changes in transfer systems create or destroy one component of life‐cycle wealth—transfer wealth. The decline in the familial transfer system in Taiwan and reform of the US Social Security system are two examples of ways that transfer wealth is reduced. The combined effects of aging and changes in transfer systems are analyzed using simulation analysis. Rapid aging and radical decline in transfer systems lead to a large but transitory surge in aggregate saving. Capital per worker increases rapidly and remains at a high level.     

Life-cycle economic model of small treatment wetlands for domestic wastewater disposal

Total system life costs (capital cost and ecological based on released pathogens) were modeled for two-cell domestic treatment wetland systems and compared to costs of traditional and emerging technology systems. Small treatment wetlands that were operationally effective for 20-years had net present value (NPV) costs $500–3000 less than those of sand filter systems. The same treatment wetlands were modeled as releasing ∼4 times pathogens, thus having a much higher ecological cost than sand filter systems. Wetland systems modeled using the highest possible pathogen treatment efficiencies still released ∼2 times the pathogens of sand filter systems. Treatment wetlands must function a minimum of 10 years before replacement in order to remain equivalent in cost to a sand filter lasting 20-years using a 6.25% discount rate. The maximum allowable installation costs for any alternative system (with no annual expenses) were $6675–7700 if required to be equal in total system NPV costs to wetlands. NPV costs were found to be particularly sensitive to uncertainties in installation and maintenance costs. Modeling indicated that the capital savings realized using wetland systems could be used to modify the simple 2-cell design such that both capital and ecological loads delivered to the environment could be minimized. Wetlands may provide a more sustainable option for communities if effluent is centralized and treated in an appropriately scaled wetland system.     

The automobile road to technological change : Diffusion of the automobile as a process of technological substitution

Advancement of the motor vehicle and its production methods is analyzed as a process of technological change. In a broader context, motor vehicles evolved as an integral component of road transportation through a series of interlaced substitutions of old by new technologies. Building on a large number of studies that described technological substitution processes, first it is shown how new energy forms replaced their predecessors and how the old marine-transport technologies were substituted by new ones. These examples constitute some of the oldest, empirically documented technological changes and show that many events in the dynamics of energy substitution and marine transport are related to technological changes in road transportation. It is shown that these substitution processes can be described by simple rules and that the replacement of old by new technologies in the energy and transport systems lasted about 80 years. The technological changes within road transportation, however, were more rapid. Replacement of horses by automobiles and older by newer generations of motor vehicles and production methods lasted only a few decades in the United States. Thus, technological substitutions within the road-transportation system were considerably shorter than the expansion of railroads, surfaced roads, all road vehicles together, and the more recent expansion of air transportation.     

Reconciling sustainability, systems theory and discounting

Most definitions of sustainability imply that a system is to be maintained at a certain level, held within certain limits, into the indefinite future. Sustainability denies run-away growth, but it also avoids any decline or destruction. This sustainability path is hard to reconcile with the renewal cycle that can be observed in many natural systems developing according to their intrinsic mechanisms and in social systems responding to internal and external pressures. Systems are parts of hierarchies where systems of higher levels are made up of subsystems from lower levels. Renewal in components is an important factor of adaptation and evolution. If a system is sustained for too long, it borrows from the sustainability of a supersystem and rests upon lack of sustainability in subsystems. Therefore by sustaining certain systems beyond their renewal cycle, we decrease the sustainability of larger, higher-level systems. For example, Schumpeter's theory of creative destruction posits that in a capitalist economy, the collapse and renewal of firms and industries is necessary to sustain the vitality of the larger economic system. However, if the capitalist economic system relies on endless growth, then sustaining it for too long will inevitably borrow from the sustainability of the global ecosystem. This could prove catastrophic for humans and other species. To reconcile sustainability with hierarchy theory, we must decide which hierarchical level in a system we want to sustain indefinitely, and accept that lower level subsystems must have shorter life spans. In economic analysis, inter-temporal discount rates essentially tell us how long we should care about sustaining any given system. Economists distinguish between discount rates for individuals based on personal time preference, lower discount rates for firms based on the opportunity cost of capital, and even lower discount rates for society. For issues affecting even higher-level systems, such as global climate change, many economists question the suitability of discounting future values at all. We argue that to reconcile sustainability with inter-temporal discounting, discount rates should be determined by the hierarchical level of the system being analyzed.     

基于消费者视角的电动汽车全寿命周期成本模型及分析

本文以全寿命周期成本理论为基础,从消费者角度对电动汽车全寿命周期内的成本进行了全面分析,建立了电动汽车的全寿命周期成本模型,为电动汽车的保有成本估算提供了方法依据。同时,将电动汽车与燃油汽车就成本进行了比较分析。结论表明,电动汽车的全寿命周期成本远低于燃油汽车,在同等条件下理性消费者会更倾向于选择电动汽车。     

区域配电网全寿命周期成本优化研究

为了有效控制配电网运营成本和提高效益,针对新一轮电力体制改革的深入改革,区域配电网全寿命周期成本优化已成为一个重要研究方向。本文首先借助系统动力学模型分析了配电网复杂成本构成和筛选了影响成本的关键因子,并采用了改进蒙特卡法对关键影响因子进行混合抽样,得出配电网各关键因子对区域配电网全寿命周期成本影响的综合灵敏度系数;其次,建立了以关键影响因子对配电网全寿命周期成本总影响量最小为目标的成本优化模型,以及提出了GAACS组合算法对模型进行求解;最后,选取了某省的10kV配电网区域进行了实例分析,结果可得,经济条件对配电网成本影响最大,以及技术条件差的区域降低成本能力较大。。     

Beyond Normal Failures: Dynamic Management of Software Projects

The skillset focusing on the life cycle of projects is critical to both understanding and practising sound management. In practice, attention is often paid to the actions and procedures required to build the system to the detriment of the tasks that are essential in managing the project. Discrete attempts to create such systems often lead to a mismatch between system, expectation and a changing reality. This paper looks beyond discrete processes as part of an effort to generate a dynamic model. The rationale for a Dynamic Feedback Model stems from the need to focus on a continuous and long-term perspective of development and growth in change-intensive environments. The paper makes the case for a learning and knowledge-driven view of software development and presents such a model in a way that accounts for the long-term survival, growth and evolution of software-intensive systems-- crucial areas in terms of the success of systems. While the emphasis is on the development of software, which is pervasive in most systems, the key issues appear to pertain to most technical development projects and environments.     

基于演化博弈企业创新模式的策略研究

处于不同生命周期的企业面临的策略选择是不同的,通过博弈模型的假设,分析了企业合作与竞争的影响因素,结合企业不同发展阶段的影响因素的特点,提出了不同阶段的策略模式选择。从企业的不同生命周期的模型假设看出,竞争与合作策略选择是随着企业不同的发展阶段,各自的成本,收益以及在市场上是否处于有利地位的不同而不同的。对于企业而言,处于不同的生命周期,其面对的内外部环境是不同的,因此选择不同的战略模式,即选择不同降段的创新模式来实现各自更好更快的发展。     

Consumption over the life cycle: How different is housing?

Micro data over the life cycle show different patterns for consumption for housing and non-housing goods: The consumption profile of non-housing goods is hump-shaped, while the consumption profile for housing first increases monotonically and then flattens out. These patterns hold true at each consumption quartile. This paper develops a quantitative, dynamic, general equilibrium model of life-cycle behavior, that generates consumption profiles consistent with the observed data. Borrowing constraints are essential in explaining the accumulation of housing stock early in life, while transaction costs are crucial in generating the slow downsizing of the housing stock later in life.     

Gains and losses from potential bilateral US–China trade retaliation

Two closely related numerical general equilibrium models of world trade are used to analyze the potential consequences of US–China bilateral retaliation on trade flows and welfare. One is a conventional Armington trade model with five regions, the US, China, EU, Japan and the Rest of the World, and calibrated to a global 2009 micro consistent data set. The other is a modified version of this model with monetary non-neutrals and including China's trade surplus as an endogenous variable.Who may gain or loss from global trade conflicts spawned by adjustment pressures in the post crisis world is much debated. In a US–China trade conflict, Europe and Japan would seem gainers from preferential access to US and Chinese markets. The loss of markets would hurt the US, but moving closer to an optimal tariff could be the source of terms of trade gains. And the ease of substitution across trading partners' practices would determine costs for China.Results from the conventional model suggest that retaliation between the two countries can be welfare improving for the US as it substitutes expenditures into own goods and improve its terms of trade with non-retaliatory regions, while China and non-retaliatory regions may be adversely affected. Results in the endogenous trade surplus model from the central case model specification, however, suggest that both the US and the EU (the deficit regions) have welfare losses in most cases, while the surplus region, China, and the ROW have welfare gains. In both models, when the bilateral tariff rates are very high, gains accrue to the EU and Japan from trade diversion if the substitutions elasticities of imports are high. Costs are borne by the US and China in lost exports, lowered terms of trade and adjustment costs at home.     

Modelling the demand for housing over the life cycle

We model individual demand for housing over the life cycle, and show the aggregate implications of this behaviour. Individuals delay purchasing their first home when incomes are low or uncertain. Higher house prices lead households to downsize, rather than to stop being owners. Fixed costs (property transactions taxes) have important impacts on welfare (a wealth effect) and house purchase decisions (substitution effect). In aggregate, positive house price shocks lead to consumption booms among the old but falls in consumption for the young, and reduced housing demand; positive income shocks lead to consumption booms among the young and increased housing demand.     

Intertemporal Labor Supply and Human Capital Accumulation*

We solve and estimate a dynamic model that allows agents to optimally choose their labor hours and consumption and that allows for both human capital accumulation and savings. Estimation results and simulation exercises indicate that the intertemporal elasticity of substitution is much higher than the conventional estimates and the downward bias comes from the omission of the human capital accumulation effect. The human capital accumulation effect renders the life‐cycle path of the shadow wage relatively flat, even though wages increase with age. Hence, a rather flat life‐cycle labor supply path can be reconciled with a high intertemporal elasticity of substitution.     

Adjustment costs and threshold effects in factor demand relationships

It has been recently argued that producers may not respond to every input price change in the way that a linear factor demand model would predict. This lumpy response is due to adjustment costs that are inherent in the act of adjusting the mix of inputs applied in the underlying production technologies. This study aims to provide a solid conceptual framework for these nonlinearities in factor demand relationships. Industry-specific implications of convex and non-convex adjustment costs for the linearity of the factor demand relationships as well as price and substitution elasticities are explored. A two-regime threshold system of factor demand equations is estimated for several manufacturing industries in the United States. Empirical results suggest significant threshold effects in the factor demand relationships in most nondurable goods sectors. The size and the nature of thresholds depend upon industry characteristics, including input composition and (non)convexity of underlying adjustment costs. Complete matrices of price and substitution elasticities for each industry are derived using estimates of threshold factor demand systems. Discussion of two contrasting cases in greater detail sheds light on how the effect of price shocks on factor demand relationships varies across industries with different adjustment cost structures.     

Intertemporal substitution and the liquidity effect in a sticky price model

The liquidity effect, defined as a decrease in nominal interest rates in response to a monetary expansion, is a major stylized fact of the business cycle. This paper first confirms that, with separable preferences, a low degree of intertemporal substitution in consumption is a necessary condition for the existence of the liquidity effect. In contrast to this result, in a model with non-separable preferences and capital accumulation it takes an implausibly high elasticity of intertemporal substitution to produce a liquidity effect. The robustness of these results to alternative degrees of nominal rigidities, capital adjustment costs and stochastic monetary processes is also analysed. We conclude that price stickiness, by itself, does not guarantee the existence of a liquidity effect.     

(S, s) Inventory Policies in General Equilibrium

We study the aggregate implications of (S, s) inventory policies ina dynamic general equilibrium model with aggregate uncertainty. Firms in themodel's retail sector face idiosyncratic demand risk, and (S, s) inventory policies are optimal because of fixed order costs. The distribution ofinventory holdings affects the aggregate outcome in two ways: variation inthe decision to order and variation in the rate of sale through the pricingdecisions of retailers. We find that both mechanisms must operate toreconcile observations that orders are more volatile than, and inventoryinvestment is positively correlated with, sales, while remaining consistentwith other salient business cycle characteristics. The model exhibits strongamplification for some shocks and persistence to a limited extent.     

Consumption over the life cycle: The role of annuities

We explore the quantitative implications of uncertainty about the length of life and a lack of annuity markets for life cycle consumption in a general equilibrium overlapping generations model in which markets are otherwise complete. Empirical studies find that consumption displays a hump shape over the life cycle. Our model exhibits life cycle consumption that is consistent with this pattern. Our calibrated model, which includes an unfunded social security system, displays a hump shape but the peak occurs later in the life cycle than in the data. Adding a bequest motive causes this decline to begin at a younger age.     

Entry costs and stock market participation over the life cycle

Several explanations for the observed limited stock market participation have been offered in the literature. One of the most promising is the presence of market frictions mostly in the form of fixed entry and/or transaction costs. Empirical studies point to a significant structural (state) dependence in the stock market entry decision, which is consistent with costs of this type. However, the magnitude of these costs is not yet known. This paper focuses on fixed stock market entry costs. I set up a structural estimation procedure which involves solving and simulating a life cycle intertemporal portfolio choice model augmented with a fixed stock market entry cost. Important features of household portfolio data (from the PSID) are matched to their simulated counterparts. Utilizing a Simulated Minimum Distance estimator, I estimate the coefficient of relative risk aversion, the discount factor and the stock market entry cost. Given the equity premium and the calibrated income process, I estimate a one-time entry cost of approximately two percent of the permanent component of the annual labor income. My estimated model matches the zero median holding as well as the hump-shaped age–participation profile observed in the data.     

Liquidity constraints, precautionary saving and aggregate consumption: an international comparison

This paper has three objectives. First, to expand Hall's [J. Polit. Econ. 86 (1978) 971] rational expectations permanent income/life cycle hypotheses (REPIH/RELCH) representative agent model to allow for current income consumers, the durable component of total consumer expenditures and for intertemporal substitution, which are often cited as the main reasons for the rejection of Hall's model. Second, to apply this modified model to 20 OECD countries over the post-World War II period. The GMM estimation method is employed. Third, to examine the relative influence of liquidity constraints and precautionary saving on the cross-country variation in the proportion of current income consumers, using cross-country regressions and a non-linear model of panel data. The presence of current income consumers, which is primarily due to liquidity constraints and to a lesser extent to precautionary saving, is the major factor for the rejection of the basic REPIH/RELCH model in all OECD countries.     

A Fiscal Stimulus and Jobless Recovery

We analyze the effects of a government‐spending expansion in a dynamic stochastic general equilibrium model with Mortensen–Pissarides labor‐market frictions, deep habits in private and public consumption, investment adjustment costs, a constant elasticity of substitution (CES) production function, and adjustments in employment at both intensive and extensive margins. The combination of deep habits and CES technology is crucial. The presence of deep habits magnifies the responses of macroeconomic variables to a fiscal stimulus, while an elasticity of substitution between capital and labor in the range of available estimates allows the model to produce a scenario compatible with the observed jobless recovery.     

有限理性、异质预期与房价内生演化机制

本文通过将传统蛛网模型推广为双边异质预期蛛网模型,分析了房价的内生演化机制,通过数值分析考察了市场参与者心理预期对房价的影响。结论表明,市场中基本面分析者的预期不影响房价动态系统的稳定性,技术分析者与开发商的预期则导致房价波动,进而影响房价动态系统的稳定性。模型还给出了房地产开发成本对房价动态演化的影响。开发成本不仅对基本面价格有正向冲击,而且当成本增加到一定临界值后也将导致房价演化出现分岔。