Hyperbolic normal stochastic volatility model

For option pricing models and heavy-tailed distributions, this study proposes a continuous-time stochastic volatility model based on an arithmetic Brownian motion: a one-parameter extension of the normal stochastic alpha-beta-rho (SABR) model. Using two generalized Bougerol's identities in the literature, the study shows that our model has a closed-form Monte Carlo simulation scheme and that the transition probability for one special case follows Johnson's distribution—a popular heavy-tailed distribution originally proposed without stochastic process. It is argued that the distribution serves as an analytically superior alternative to the normal SABR model because the two distributions are empirically similar.     

山西省乡村休闲旅游地空间分布特征及影响因素研究

［目的］通过对山西省乡村休闲旅游地的空间分布特征及影响因素进行研究，旨在为山西省的乡村旅游发展提供合理的参考建议。［方法］选取山西省213处国家级和省级乡村旅游示范点为研究对象，运用最临近点指数对其空间分布类型进行判别，并运用地理集中指数和地理联系率对其分布均衡程度和地理联系程度进行考量，通过核密度图进一步分析其空间分布指向，在此基础上对影响因素进行分析。［结果］山西省乡村休闲旅游地空间分布呈集聚分布的特点，且与经济规模和人口密度在空间上的均衡、配合程度较高。［结论］（1）山西省乡村休闲旅游地包括以太原和晋中为主的中部密集区和以临汾、运城、晋城为主的南部密集区，且都以各地级市为中心向周边扩展，大多数示范点分布于城郊地区； （2）经济发展、人口密度、资源禀赋、区位因素和社会因素是影响山西省乡村休闲旅游地分布的主要因素，其中农业科技类、农事体验类和特色村镇类多分布于经济和人口密度较高的地区。     

LT码新型度分布及其在电力线通信中的应用

Luby变换(Luby Transform,LT)码作为信道编码应用于电力线通信(Power Line Communication,PLC)，可实现电信号的可靠传输。度分布对LT码编译码性能的影响至关重要。为了得到更优的度分布，首先调整二进制指数分布(Binary Exponential Distribution,BED)中的度数比例，获得一种译码性能更优的改进的二进制指数分布(Improved BED,IBED)。然后，根据IBED在冗余度较小时译码成功率高，而冗余度增大后鲁棒孤子分布(Robust Soliton Distribution,RSD)的译码性能表现更佳的特点，通过求和归一化的方式将IBED与RSD两种度分布的优势进行有机结合，提出一种新型二进制鲁棒孤子分布(Binary RSD,BRSD)。仿真结果表明，与其他方法及传统的RSD相比，采用新度分布进行LT编码，可明显降低译码开销，并节约编译码耗时。将新型度分布应用于基于LT码的PLC系统中，能有效地抑制PLC信道中各种噪声对电信号的干扰，并提高通信效率。     

平顶山市休闲农业不同区域的发展潜力评价

[目的]对平顶山市休闲农业的空间分布特征及其发展潜力进行分析和评价,以期为平顶山市休闲农业的可持续发展提供参考和借鉴。[方法]文章对平顶山市休闲农业空间布局分区论述,并采用层次分析法构建平顶山市休闲农业发展潜力指标评价体系,确定指标权重,然后根据各指标的游客和当地农民的打分值与权重值加权计算不同区域的发展潜力指数并比较发展潜力大小。[结果]根据区域位置和地理环境以及休闲农业发展速度,将平顶山市休闲农业划分为北部山区休闲农业区、东部城乡休闲农业区、南部现代休闲农业区和西部傍水休闲农业区4个区域,各区域发展特点突出。对各指标权重值与打分值的加权求和计算得到的不同区域发展潜力指数看出,西部傍水休闲农业区的发展潜力最大,其次为北部山区休闲农业区,再者是南部现代休闲农业区,东部城郊休闲农业区的发展潜力最小。[结论]平顶山市休闲农业发展前景广阔,具有可持续发展的巨大潜力。由于地理区位和交通基础设施建设及环境条件和农业基础的差异,平顶山市的休闲农业可分为东西南北4个发展区域,其中西部傍水休闲农业区和北部山区休闲农业区具有较大的发展潜力,平顶山市可将其作为重点发展对象,重点打造水岸和山村休闲农业游,借助发展优势突出区域特色。     

甘孜州农牧区县域发展水平综合评价与特征分析

[目的]对甘孜州各县市的发展状况进行研究探讨,为区域可持续发展策略的制定实施提供科学依据,对提升县域发展水平和发展质量具有重要意义。[方法]建立涵盖经济、社会、资源环境三大模块共计24项指标的评价体系,选取发展较快的2007—2014年为研究时段,运用极差法、改进熵值法、耦合协调度模型与GIS工具,对甘孜州各县市的发展水平进行综合评价与分析。[结果](1)全州综合发展水平指数平均值为0. 500 8,发展水平整体较低,其中康定市得分最高,石渠县最低,县市之间呈现两级分化。(2) 2007—2014年全州综合发展指数平均增幅0. 262 6,年均增速13. 77%,所有县市均处于上升过程,但县市之间增速不一,发展差距逐步扩大。(3)全州发展协调度平均值为0. 390 5,协调度较低,各县市均处于轻度失调或濒临失调水平。(4)发展水平、活力、协调度较高县市均集聚于州东部和南部,尤以东路片区最为典型。[结论]下一阶段需依据各县市实际,立足优势,制定实施合理的发展规划,缩小区域差异,提升综合发展水平。     

Modelling tourist flow association for tourism demand forecasting

The purpose of this study is to examine tourism demand for Singapore from 1995 to 2013 by six major origin countries which belong to three different regions. Unlike prior tourism research, we take into account the dependence relations among the different tourist flows via copula. Copula is a statistical model of dependence and measurement of association. Specifically, we investigate the association between two tourist flows in each region. Based on empirical copula estimation, the Frank function has been identified as the most appropriate to capture the pairwise dependence structures of tourist flows. The copula-based approach combined with econometric models is proposed for tourism demand analysis that can be used to predict tourist arrivals. We apply the copula-ARDL and copula-ECM frameworks to generate joint forecasts of tourist arrivals from three regions. The findings show that the forecast performance of the Frank copula-based model outperforms the benchmark model which corresponds to the independence structure (no association) of tourist flows.     

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.     

Understanding the travel motivation and patterns of international students in Korea: using the theory of travel career pattern

This study examined the travel motivation of international students in Korea using the theory of travel career pattern (TCP). In particular, latent profile analysis (LPA) was applied to identify latent classes within international students. Based on the results, four latent profiles were derived and named “Core,” “Longing,” “Middle,” and “Veteran.” The results described the travel motivation and patterns across these four profiles to enhance the understanding of international students in the context of tourism. There were significant differences in travel patterns (i.e. travel companion and information sources) among the profiles segmented by motivation. This study has expanded travel motivation research by (a) applying TCP to an understudied population (i.e. international students in a non-English-speaking country); (b) comparing travel careers between the home country, Korea (i.e. a study abroad destination), and the third countries; and (c) highlighting LPA as a clustering tool to understand travel motivation.     

Income Polarization of the U.S. Working Class: An Institutionalist View

We provide an institutional insight into the trend of income polarization within the U.S. working class. In contrast to the previous industrial waves, the current and ongoing industrial revolution is characterized by the replacement of “creative destruction” with jobless growth. Instead of replacing the lost jobs with new ones, new disruptive technologies eliminate more jobs in traditional labor and capital-intensive sectors than create jobs in new idea-intensive sectors. By examining the relationship between the income share of the bottom 50 percent, the middle 40 percent, and the top 10 percent and technological progress, we obtain robust econometric results. According to our results, the income polarization among U.S. workers can be associated with the shift of R&D activities from the public to the corporate sector. The concentration of innovations by corporate capital limits the power of society to reduce inequality and to provide greater social stability through “the incredible productivity” of technological progress.     

刚度不均匀分布的连体结构的抗震性能分析

通过连接体将两个或两个以上的独立塔楼连接在一起,形成连体结构。在地震作用下,塔楼的变形和内力变化复杂,且两塔楼之间的耦联效果显著。本文采用弹塑性时程分析法,研究其在罕遇地震作用下的动力响应,并且通过对不同对称性、平面内不同刚度分布、不同跨度的结构进行弹塑性时程分析,分析结构的对称性、跨度的参数对结构动力响应的影响。