Equitable preference relations on infinite utility streams

We propose generalized versions of strong equity and Pigou–Dalton transfer principle. We study the existence and the real-valued representation of social welfare relations satisfying these two generalized equity principles. Our results characterize the restrictions on one period utility domains for the equitable social welfare relations (i) to exist; and (ii) to admit real-valued representations.     

Fuzzy modelling of static system optimum traffic assignment problem having multi origin-destination pair

Traffic congestion is an unpreventable problem to avoid in a transportation network and it has negative effects on traffic accident, time wasting, traffic delay and safety problem. Besides, in transportation networks, drivers do not want to deal with traffic jam while traversing between specified origin-destination pair. Therefore, traffic assignment (TA) is imperative to improve traffic management, transportation safety, time, and cost savings. System Optimum Traffic Assignment Problem (SOTAP) is a kind of TA model which aims to minimize the total system travel time on the network, and satisfies the flow conservation constraints. To model the SOTAP more realistically, the imprecise parameters can be taken as fuzzy. Therefore, in this paper, we focus on converting the conventional SOTAP to a fuzzy quadratic programming problem (QPP) which is named System Optimum Fuzzy Traffic Assignment Problem (SOFTAP). Here, link travel time is expressed with BPR function as generally used in the literature by converting to fuzzy except link-dependent parameters. Thus, the nonlinear objective function of SOFTAP is expressed in terms of fuzzy link flows and fuzzy link travel times. A solution approach from the literature is modified to the reconstructed SOFTAP.     

Excess capacity,production technology and technical inefficiency in hospitality sector

This article examines the effects of excess capacity on the production cost and technical inefficiency of hotels and restaurants in Norway. The dataset includes a daily unbalanced panel of 94 hotels and restaurants from 2003 to 2014. To accommodate inefficiency, we use an input distance function (IDF). Inefficiency in the IDF means that if inputs are overused by k% then production cost is also increased by k%. We also allow inefficiency to differ across locations and regions by using them as determinants. The results indicate that excess capacity considerably affects the cost and increases inefficiency. The marginal effect on cost increases with excess capacity, but the effect on inefficiency sets in when it exceeds 50 percent. Furthermore, we find less overuse of inputs by firms in small metro towns and the Northern region causing them to be more efficient [except for the Southern and Western regions] than their counterparts.     

中国农村宅基地闲置程度及其成因研究

研究目的：基于全国典型村庄调研，分析不同地区农村宅基地闲置程度和成因，为农村宅基地集约利用和乡村振兴提供建议。研究方法：实地调研法、对比分析法。研究结果：（1）调研村庄宅基地闲置现象普遍，2018年闲置程度平均为10.7%。（2）各地村庄宅基地闲置程度差异明显。分区域看，东部村庄宅基地闲置程度最高，中部村庄最低；分城乡区位看，村庄离城市距离越远，宅基地闲置程度越高；分地形看，平原村庄宅基地闲置程度最高；分是否为贫困村庄看，村庄宅基地闲置程度随村庄贫困程度的加深而升高。（3）宅基地闲置是乡村人口结构变化与宅基地利用失衡的结果。长期外出务工、城镇有住房、“一户多宅”、宅基地损毁引起宅基地闲置的成因占比依次下降。（4）农村宅基地闲置受乡村地域内外宏微观因素综合影响，经济增长和城镇化引起的就业非农化、人口市民化是宅基地闲置的直接动因，现行城乡二元制度和宅基地管理制度是宅基地闲置的根本原因。研究结论：盘活利用农村闲置宅基地，需要因地制宜推动闲置宅基地整治利用、健全宅基地有偿使用和退出机制、创新城乡制度加快农业转移人口市民化。     

Predictive regressions under asymmetric loss: Factor augmentation and model selection

This paper discusses the specifics of forecasting using factor-augmented predictive regressions under general loss functions. In line with the literature, we employ principal component analysis to extract factors from the set of predictors. In addition, we also extract information on the volatility of the series to be predicted, since the volatility is forecast-relevant under non-quadratic loss functions. We ensure asymptotic unbiasedness of the forecasts under the relevant loss by estimating the predictive regression through the minimization of the in-sample average loss. Finally, we select the most promising predictors for the series to be forecast by employing an information criterion that is tailored to the relevant loss. Using a large monthly data set for the US economy, we assess the proposed adjustments in a pseudo out-of-sample forecasting exercise for various variables. As expected, the use of estimation under the relevant loss is found to be effective. Using an additional volatility proxy as the predictor and conducting model selection that is tailored to the relevant loss function enhances the forecast performance significantly.     

Computing the Gerber–Shiu function by frame duality projection

Inspired by some works of Kirkby, J. L. [2015. Efficient option pricing by frame duality with the fast Fourier transform. SIAM Journal on Financial Mathematics 6(1), 713–747; 2016. An efficient transform method for Asian option pricing. SIAM Journal on Financial Mathematics 7(1), 845–892], we present a systematic study on effectively computing the Gerber–Shiu function in the Lévy risk model, where the frame duality projection is used for approximation. By introducing an auxiliary function, we provide a smooth extension of the Gerber–Shiu function, which has closed-form Fourier transform and is differentiable over the whole real line under some conditions. The objective function is approximated by its frame duality projection onto a Riesz basis, and the projection coefficients are readily computed by the fast Fourier transform algorithm. Error analysis is made and the effectiveness of our results will be further illustrated in the numerical experiments.     

The impact of climate change on labour demand in the plantation sector: the case of tea production in Sri Lanka

Limited opportunities for crop switching and lengthy preharvesting periods make the plantation sector particularly vulnerable to climate change. Surprisingly, however, the economic consequences of climate change on plantation crops are seldom analysed. Drawing on a unique primary panel data set from a representative cross section of 35 tea estates in Sri Lanka over the period 2002–2014, this study implements a structural model of estate profit maximisation to estimate the elasticity of labour demand with respect to different components of weather. Results indicate a negative relationship between labour demand and rainfall in the south‐west monsoon, the north‐east monsoon and the second inter‐monsoon. A positive relationship is found between labour demand and rainfall in the first inter‐monsoon. Overall, predicted changes in rainfall by 2050 are anticipated to reduce labour demand by approximately 1,175,000 person‐days per year across Sri Lanka's tea plantation sector. This is likely to have considerable social and welfare implications, particularly for the Indian Tamil women who comprise the majority of the sector's workforce.     

Sustainability of the fiscal imbalance and public debt under fiscal policy asymmetries in Sri Lanka

This paper investigates the sustainability of Sri Lanka’s fiscal imbalance and public debt. To test for sustainability of the fiscal imbalance, the study applies a symmetric ARDL (autoregressive distributive lag) technique to estimate a government intertemporal budget constraint. And to test for sustainability of public debt, it applies an asymmetric ARDL technique to estimate a fiscal reaction function, which allows for differential responses in the primary budget balance depending on whether shocks to regressors are positive or negative. Annual data for the period 1961–2018 are used in the estimations. The results indicate that Sri Lanka’s fiscal management is inconsistent with strong form sustainability, which requires that expenditures not grow faster than revenues. However, estimation of the fiscal reaction function finds robust evidence for fiscal policy asymmetries. Evidence emerges that Sri Lanka’s fiscal policy stance is procyclical with strong stabilization tendencies in economic expansions that are not sustained in contractions. Against upsurges in the debt-to-GDP ratio, authorities are found to pursue fiscal consolidation, thus suggesting weak form sustainability.     

一种级联两箱通用数字预失真器及其辨识算法

提出了一种由单形规范线性分段(SCPWL)函数与记忆多项式级联的数字预失真器，并给出了复数域两步最小二乘参数辨识算法。不同于以往一种预失真器适用一种功放模型的情况，所提的预失真算法利用SCPWL函数的分段特性以及记忆多项式的非线性记忆特性，在完成参数辨识的同时自动地调整结构，可适用于传统以及强非线性新型功放模型的线性化补偿。将所提预失真器分别应用于传统记忆多项式、两箱模型以及新型包络跟踪功放。经过计算机仿真，功放输出的幅频特性和频谱曲线表明所提预失真器能够有效地补偿多种功放的非线性特性。算法仿真比较结果也表明，针对包络跟踪功放，所提复数两步最小二乘算法的邻道泄漏比(ACLR)可改善约35 dB，性能优于最小均方(LMS)类算法约30 dB。     

Ruin probabilities in classical risk models with gamma claims

In this paper, we provide three equivalent expressions for ruin probabilities in a Cramér–Lundberg model with gamma distributed claims. The results are solutions of integro-differential equations, derived by means of (inverse) Laplace transforms. All the three formulas have infinite series forms, two involving Mittag–Leffler functions and the third one involving moments of the claims distribution. This last result applies to any other claim size distributions that exhibits finite moments.