波音737NG整流罩防冰系统简介及常见故障分析

本文主要针对飞机整流罩防冰系统的基本工作原理,以及在运行过程中出现的典型整流罩防冰系统的故障进行综合分析和采取处理的方法。     

Hyperbolic Discounting and Consumer Patience: The Case of Korea

ABSTRACT

In this article, we test whether the consumption pattern in Korea exhibits a time-inconsistent discounting behavior compared to the conventional exponential discounting. We derive the quasi-hyperbolic Euler equation and estimate it using the generalized method of moments (GMM). The estimation results show that Korean consumers exhibit a time-inconsistent quasi-hyperbolic discounting behavior in general, but the pattern of inconsistency in consumption behavior, in particular the degree of impatience, depends on the estimation period, in particular whether it includes financial crisis periods in 1997–98 and 2008–11.     

Public sector enterprise disinvestment in India: Efficiency gains in a political context

India instituted a program of state enterprise disinvestment in 1991 as part of a sweeping reform initiative. This study analyses the effect of disinvestment on enterprise performance, conditioned on political context as characterized by the ideological leanings of the parties in power at state and central levels. Using stochastic frontier analysis, measures of firm efficiency are generated for 238 central public sector enterprises for the period 1991–1992 to 2010–2011. The relationship between efficiency so measured and disinvestment is then estimated using a two-stage instrumental variables approach to control for endogeneity between firm efficiency and selection for disinvestment. Initial disinvestment is associated with substantial efficiency gains, but subsequent disinvestment much less so and the proportion of shares disinvested only loosely so. This may be explained by the transformative effect of initial stock market listing on accountability and profit orientation that is not repeated with further rounds of disinvestment. The effect of disinvestment on performance is stronger if the enterprise is located in a state governed by a right leaning party or one that is ideologically aligned with the party in power at the centre.     

Planning road networks in landslide-prone areas: A case study from the northern forests of Iran

Road development in mountainous forestlands can lead to naturally formed slopes being disturbed. Efficient planning methodologies can assist forest engineers in either preventing or reducing the environmental impacts of forest roads. In this study, we first prepared an inclusive landslide susceptibility map for our study area using a Bayesian model. We next designed 12 road network alternatives using PEGGER, an ArcView GIS extension. We extracted the values of these alternatives from the susceptibility map to evaluate their environmental feasibility. We also evaluated the alternatives from an economic perspective using a model for conducting cost estimates of the forest roads. Our results show that this approach is useful for identifying the alternative that meets environmental and economic goals. The policy implications of this study suggest that if the development of road networks in mountainous areas is an important forestry goal, mechanisms should be aimed primarily at controlling slope instability.     

Fiscal financing and the efficacy of fiscal policy in Korea: An empirical assessment with comparison to the U.S. evidence

This paper aims to assess the empirical implications of fiscal financing in Korea and study how they differ from those of the U.S. We estimate two versions of the dynamic stochastic general equilibrium (DSGE) model—a small open economy (SOE) model for Korea and its closed economy counterpart for the U.S.—in which the former nests the latter as a special case. The fiscal policy specification posits that government spending, lump-sum transfers, and distortionary taxation on labor income, capital income and consumption expenditures respond to the level of government debt and the state of economic activity. Analysis of the data from 2000 to 2015 shows that distortionary capital taxes play a critical role in stabilizing government debt in the U.S., whereas non-distorting fiscal instruments are the primary means of fiscal adjustment in Korea. Regarding the magnitude of debt-financed fiscal stimuli, the substantial trade openness of Korea is significant in that it produces relatively smaller government spending and transfer multipliers compared to the U.S.     

一种改进的CPFSK信号频率估计方法

针对突发信号解调中多普勒频偏大的问题，提出了一种改进的连续相位移频键控信号(CPFSK)频率估计方法。首先接收信号平方运算使信号的调制指数加倍，再通过一次离散傅里叶变换(DFT)，用搜索信号平方谱谱峰的方法实现突发信号频率估计。仿真实验表明，在低信噪比条件下，该算法的频率估计精度比经典的相位差频率估计算法提高了20%；该算法与广泛用于高动态突发信号的频率插值估计算法相比，同道干扰信道下信干比改善可达4 dB，DFT长度缩短约1/3。     

The expected real yield and inflation components of the nominal yield curve

The term structure of real yields and expected inflation are two unobserved components of the nominal yield curve. The primary objectives of this study are to decompose nominal yields into their expected real yield and inflation components and to examine their behaviour using state-space and regime-switching frameworks. The dynamic yield-curve models capture three well-known latent factors – level, slope, and curvature – that accurately aggregate the information for the nominal yields and the expected real and inflation components for all maturities. The nominal yield curve is found to increase slightly with a slope of about 120 basis points, while the real yield curve slopes upward by about 20 basis points, and the expected inflation curve is virtually flat at slightly above 2 per cent. The regime-switching estimations reveal that the nominal yield, real yield and expected inflation curves have shifted down significantly since 1999.     

How Productive Is Workplace Health and Safety?

In this paper, we investigate the causal impact of workplace health and safety practices on firm performance, using Danish longitudinal matched employer–employee data merged with unique cross‐sectional representative firm survey data on work environment conditions. We estimate standard production functions, augmented with workplace environment indicators, addressing both time‐invariant and time‐varying potentially relevant unobservables in the production process. We find positive and large productivity effects of improved physical dimensions of the health and safety environment, specifically, “internal climate” and “monotonous repetitive work”.     

Nonparametric fixed effects model for panel data with locally stationary regressors

We develop methods for inference in nonparametric time-varying fixed effects panel data models that allow for locally stationary regressors and for the time series length $T$ and cross-section size $N$ both being large. We first develop a pooled nonparametric profile least squares dummy variable approach to estimate the nonparametric function, and establish the optimal convergence rate and asymptotic normality of the resultant estimator. We then propose a test statistic to check whether the bivariate nonparametric function is time-varying or the time effect is separable, and derive the asymptotic distribution of the proposed test statistic. We present several simulated examples and two real data analyses to illustrate the finite sample performance of the proposed methods.     

试析计算机网络故障处理办法及维护策略

随着信息和科技时代的到来,计算机网络已经在人们生活中占据了越来越重要的位置。因此,对网络故障进行及时的处理与维护就显得更加重要。本文将对计算机网络故障的处理和维护进行分析,并提出了有关的解决策略。