基于DEA-SBM模型的中国地板上市企业环境效率研究

考虑非期望产出,基于企业层面,根据2011-2016年数据,采用DEA-SBM模型与DEA-CCR模型对中国12家地板上市公司的环境效率与经济效率进行测算与比较。结果表明:2016年环境效率和经济效率测算结果显示不同地板上市企业运行效率存在差别;与经济效率相比,一些企业如北新建材、扬子地板,环境效率保持不变,一些企业如宜华生活、吉林森工和丰林集团,环境效率得到提升;还有一些企业如兔宝宝、升达林业和大自然家居等,环境效率则出现下降。考虑了非期望产出,中国地板上市企业整体环境效率均值低于经济效率均值,总体处于0.79~0.84之间。提出了政府应加强监管力度,地板上市企业应提高技术改进能力,建立完善社会责任信息披露机制的建议。     

Islamic and conventional portfolios optimization under investor sentiment states: Bayesian vs Markowitz portfolio analysis

This paper investigates the portfolio optimization under investor’s sentiment states of Hidden Markov model and over a different time horizon during the period 2004–2016. To compare the efficient portfolios of the Islamic and the conventional stock indexes, we have employed two approaches: the Bayesian and Markowitz mean-variance. Our findings reveal that the Bayesian efficient frontier of Islamic and conventional stock portfolios is affected by the investor’s sentiment state and the time horizon. Our findings also indicate that the investor’s sentiment regimes change the Islamic and the conventional optimal diversified portfolios.Moreover, the results show that the potential diversification benefits seem to be more important when using the Bayesian approach than when applying the Markowitz approach. This finding is valid for the bearish, depressed, bullish and calm states in Islamic stock markets. However, the diversification of potential portfolios is significant only for the bullish and the bubble states in the conventional financial markets.The findings of the study provided additional evidence for investors to exploit googling investor sentiment states to evaluate the portfolio performance and make an optimal portfolio allocation.     

Modelling distribution of aggregate expenditure on tourism

The aim of this article is to obtain a statistical distribution that describes the aggregate expenditure of tourists related to their length of stay at a given location. This distribution enables us to estimate two parameters simultaneously; one controls the length of stay and the other, the expense incurred. We propose two distribution models, for which closed-form expressions are obtained. Covariates are introduced in order to study the factors that affect the aggregate expenditure. The results obtained indicate that the models achieve a reasonably good fit, with and without covariates.     

Analysis of the effect of charging infrastructure design on electric taxi driving profiles: A case study approach on the example of Singapore

Replacing conventional vehicle taxis with electric vehicles would be an efficient measure to reduce greenhouse gas emissions. Due to the limited range and long charging times of current battery electric vehicles, it is of utmost importance to provide sufficient charging facilities. This article analyses the impact of the placement and charging power of charging stations on potential mileage and revenue of electric taxis on the example of Singapore. Therefore, we developed an agent-based electric taxi simulation model to investigate electric taxis’ driving profiles with respect to different vehicle types and charging infrastructure designs. This model is also capable of simulating conventional taxi driving profiles. The validation of these simulation results with real taxi data showed that the model is reproducing taxi driving profiles with high accuracy in great detail. We found out that electric taxis could reach the same mileage and revenue as conventional taxis if charging with a power of 160?kW is possible. Furthermore, we discovered that waiting times for available charging stations have a stronger effect on revenue than the length of detours to reach charging stations. Based on these findings, we concluded that it is more important to reduce waiting times by placing sufficient numbers of charging stations at each location before expanding the charging network by installing small numbers of charging stations at many locations.     

The effect of diplomatic representation on trade: A panel data analysis

This study addresses current gaps in the empirical literature regarding the effect of diplomatic representation on trade using a panel data set for 100 countries with 5‐year interval data from 1985 to 2005 and four‐digit level industry data. The results indicate that the effect of diplomatic representation on exports in differentiated goods is positive and significant and larger than on exports in homogeneous goods on average, but not statistically different from it. Furthermore, diplomatic representation only increases trade along the extensive margin and not along the intensive margin. The results indicate that diplomatic representation is effective in performing its function as a network search intermediary and that it is a useful policy tool to alleviate market failure.     

From disruptively digital to proudly analog: A holistic typology of digital transformation strategies

Recently booming academic interest in digital transformation aims to provide continuous support to managers in dealing with this important issue. However, as with all new fields, the scholarly literature is characterized by increased variability and diversity of topics covered, constructs used, and the relationships between them, resulting in an unclear and blurry understanding of the whole of digital transformation. Our article closes this gap by identifying distinctive digital transformation strategies in terms of two critical dimensions: usage of digital technologies and readiness of a business model for digital operation. The result is a typology of four generic digital transformation strategies that essentially differ in the primary motivation and target of transformation, leadership style, importance of skills like creativity and entrepreneurial spirit among employees, risks and challenges faced in the process, consequences of potential failure, and available tactics for improvement. By providing heuristics and a systematic basis for comparison of different strategies, it is our belief that the proposed framework will be useful to researchers and managers responsible for and interested in digital transformation.     

Steady state adjusting trends using a data-driven local polynomial regression

Economic variables usually follow a dynamic trend pattern. However, it is difficult to estimate this trend precisely as numerous economically- and statistically-based estimation methods exist. This contribution proposes a data-driven nonparametric trend that is local polynomial, to improve arbitrary trend estimations of commonly used methods concerning the selection of the smoothing parameter and the dependence structure. An iterative plug-in (IPI) algorithm determines the bandwidth endogenously and allows a theory-based interpretation of the length of growth processes. This length of the bandwidth reflects the lengths of the steady state periods. Consequently, the bandwidth identifies the time period of stable economic conditions and can detect economic changes. To demonstrate the power of this estimation approach, an extensive simulation study is performed. Furthermore, examples using US and UK GDP data along with a guide for the optimal choice of algorithms for empirical applications are provided. This proposed method yields new insights for growth dynamics, cyclical movements and their dependence.     

政府间竞争影响城市土地市场化水平的双边效应研究：基于财政竞争和引资竞争的不同作用

研究目的:本文将政府间竞争划分为财政竞争和引资竞争,比较两者对城市土地市场化水平影响的大小,分析政府间竞争与城市土地市场化水平之间的关系。研究方法:基于2003—2016年全国284个地级市的面板数据,利用双边随机前沿模型测算财政竞争和引资竞争对城市土地市场化水平的影响。研究结果:财政竞争对城市土地市场化水平具有正向效应,提高了城市土地市场化水平1.61%;引资竞争对城市土地市场化水平具有负向效应,降低了城市土地市场化水平12.51%;政府间竞争总体上降低了城市土地市场化水平10.90%。时间趋势表明,政府间竞争对城市土地市场化水平的抑制作用呈现波动下降的状态。研究结论:政府间竞争降低了城市土地市场化水平。     

Employing structural topic modelling to explore perceived service quality attributes in Airbnb accommodation

This study employs the structural topic model to extract service quality attributes from 242,020 Airbnb reviews in Malaysia. 22 service related topics were extracted from the corpus and four topics have not appeared in previous Airbnb studies. A widely used modified SERVQUAL questionnaire (MSQ) is cross-validated in this study by comparing its service quality attributes with the results of the topic modelling, which indicates that this MSQ can cover general Airbnb service quality attributes. This study also examines the different preferences of Malaysian and international Airbnb users and the changing patterns of the top six service quality attributes during a five-year period. The findings reveal that Malaysian Airbnb users care more about the appearance and location of the property, and international Airbnb users pay more attention to whether the property can accommodate a group of people. In addition, communication with the host is found to play an increasingly important role in Airbnb users’ lodging experiences.     

黑龙江森工林区接替产业发展评价

运用熵权灰色关联分析法对黑龙江省森工林区所辖4个林业管理局2012—2017年养殖业、绿色食品等5个接替产业综合发展水平进行评价,并运用耦合协调度模型测算接替产业的均衡水平。结果表明:不同林业管理局的5个接替产业均呈波动发展状态;伊春林业管理局的优势接替产业是养殖业、绿色食品、北药开发和工业,牡丹江林业管理局的优势接替产业是绿色食品,合江林业管理局的优势接替产业是服务业,松花江林业管理局没有显著的优势接替产业;接替产业的综合发展水平偏低导致其均衡水平不高,总体上由初步协调向中度协调发展。因此,各林业管理局应继续发展具有优势的接替产业,同时扶持相对薄弱的接替产业,并开发与引进新的接替产业。