常德市农业投入产出模型分析

利用柯布一道格拉斯生产函数,以1999年和2005年数据为基础,对常德市农业生产的实际情况进行量化分析,以农业产值为产出因子,选择劳动力、化肥投入、机械总动力、耕地面积和有效灌溉面积为投入因子,利用EVIEW计量经济软件建立投入产出模型。通过计量经济模型对比分析发现,从1999年到2005年常德市农业产值大幅增加的主导影响因素依然是耕地面积,相对1999年劳动力和农业机械总动力的影响而言,2005年化肥投入量和农业机械总动力的影响增强,而劳动力则表现出剩余现象。说明今后常德市农业生产应做好耕地资源的开源与节流工作,重视农业科技和农业机械化发展,调整农业产业结构促进劳动力资源合理利用及优化农业产业类型的布局。     

A multiple objective particle swarm optimization approach for inventory classification

This paper presents a particle swarm optimization approach for inventory classification problems where inventory items are classified based on a specific objective or multiple objectives, such as minimizing costs, maximizing inventory turnover ratios, and maximizing inventory correlation. In addition, this approach determines the best number of inventory classes and how items should be categorized for the desired objectives at the same time. Experiments are employed to determine the best combination of algorithm parameter values. Extensive numerical studies are conducted and results are compared to other known classification methods. The performance of the algorithm on a practical case is also presented.     

A new approach to bad news effects on volatility: the multiple-sign-volume sensitive regime EGARCH model (MSV-EGARCH)

In this paper, using daily data for six major international stock market indexes and a modified EGARCH specification, the links between stock market returns, volatility and trading volume are investigated in a new nonlinear conditional variance framework with multiple regimes and volume effects. Volatility forecast comparisons, using the Harvey-Newbold test for multiple forecasts encompassing, seem to demonstrate that the MSV-EGARCH complex threshold structure is able to correctly fit GARCH-type dynamics of the series under study and dominates competing standard asymmetric models in several of the considered stock indexes.

Run equilibria in the Green–Lin model of financial intermediation

We study the Green–Lin model of financial intermediation [E.J. Green, P. Lin, Implementing efficient allocations in a model of financial intermediation, J. Econ. Theory 109 (2003) 1–23] under a more general specification of the distribution of types across agents. We derive the efficient allocation in closed form. We show that, in some cases, the intermediary cannot uniquely implement the efficient allocation using a direct revelation mechanism. In these cases, the mechanism also admits an equilibrium in which some (but not all) agents “run” on the intermediary and withdraw their funds regardless of their true liquidity needs. In other words, self-fulfilling runs can arise in a generalized Green–Lin model and these runs are necessarily partial, with only some agents participating.     

Secrecy and fairness in plea bargaining with multiple defendants

I consider a model of plea bargaining with multiple codefendants. I mainly compare the equilibrium outcomes under joint negotiations whereby both defendants can observe both plea offers and under separate (secret) negotiations whereby they can observe only their own respective offer. Contrary to the widespread perceptions, the prosecutor is made worse off under secret negotiations or at best as well off as under joint negotiations. I also discuss the implication of equilibrium offers on fairness.      

Microenterprises and multiple bank relationships: The case of professionals

The present paper focuses on professionals as a special group of microenterprises. It explains their characteristics and financial relationships, using data from a survey conducted in Germany in 2002. Consistent with the theory of asymmetric information and relationship lending, we find that these firms maintain a small number of bank relationships, which increases in firm size and age. They tend to choose multiple banking relationships to overcome credit rationing and finance larger loans. Credit risk and the structure of the banking market do not seem to matter.     

Product specialization in international trade: A further investigation

In an influential paper, Schott [Schott. Peter K. (2004). “Across-product versus within-product specialization in international trade.” Quarterly Journal of Economics, 119 (2): 647–678] makes two empirical observations about U.S. imports. (1) The United States is increasingly sourcing the same product (however narrowly defined) from both developed and developing countries. That is, ‘across-product specialization’ has been decreasing. (2) The unit values of these multiple-sourced products are positively and significantly correlated with the capital and skill abundance of exporters and with the capital–labor ratios used by exporters. That is, endowments-driven ‘within-product specialization’ has been increasing. We show that both these observations extend to the imports of Brazil, India and Japan. However, our main finding is that observation (1) is largely driven by two factors. First, China is the dominant low-wage exporter of multiple-sourced products. Second, the most developed countries remain the primary exporters of multiple-sourced products. The U.S. case is the most extreme of our four importers: When China is deleted from the U.S. import data there is no trend in across-product specialization and rich exporters are increasing their trade share of multiple-sourced products. Since deleting China has no theoretical justification, these results must be viewed not as a contradiction of Schott's work but as a way of deepening our understanding of his empirical results.     

Investigation of pedestrian crashes using multiple correspondence analysis in India

Abstract

Pedestrian safety is of growing concern with an increasing number of traffic accidents, especially in developing economies like India. In 2017, there were 20,457 pedestrian fatalities in India. Pedestrian crashes have also become a key concern in the state of Tamilnadu, India, due to the high percentage of deaths. If the available datasets are large and complex, identifying key factors is a challenging task. In this study, Multiple Correspondence Analysis (MCA), an exploratory data analysis technique was used to explore the roadway, traffic, crash, and pedestrian-related variables influencing pedestrian crashes. This study used the data from Government of Tamilnadu Road Accident Traffic Management System (RADMS) database, to analyse accident data of nine years (2009–2017) related to pedestrian crashes. The results of the study show that crashes occurring on the express highways on a multilane road are often associated with hit-and-run behaviour among drivers. Factors such as lighting conditions, location, pedestrian behaviour, crossings, and physical separation are also significantly contributing to pedestrian crashes. The key advantage of MCA is that it identifies a possible association between various contributing factors. The findings from this study will be useful for state transport authorities to improve countermeasures for mitigating pedestrian crashes and fatalities.     

Mathematical programming for nominating exchange students for international universities: The impact of stakeholders’ objectives and fairness constraints on allocations

We consider the problem of nominating exchange students to attend international universities where places are limited. We take into account three objectives: The sending university aims to maximize the number of nominations, the students seek nomination for a highly preferred university and, finally, the receiving universities strive for excellent incoming students. Pairwise comparison of students should guarantee the following fairness: A student with higher academic achievements should be preferred over a student with lower academic achievements. We provide mathematical programming models of the nomination problem which maximize the overall objectives and guarantee different types of pairwise fairness. Several years of real data from a major school are employed to evaluate the models’ performance including a benchmark against the heuristic that is used by the school. We show analytically and experimentally that the heuristic approach fails to guarantee some pairwise fairness. Our results reveal the following four insights: First, compared to the current approach, up to 6.6% more students can be nominated with our optimization model while ensuring all pairwise fairness perspectives. Second, on average, students are nominated with better academic achievements. Third, the problem instances can be solved to optimality within a fraction of a second even for large-size instances comprising more than 500 students and about 150 schools offering nearly 450 exchange places. This is important for its use in practice. Last, up to 17.9% more students can be nominated when considering the overall objective to maximize nominations.     

The political and institutional determinants of fiscal adjustments and expansions: Evidence for a large set of countries

Using annual data for 60 countries over 1980–2014, we study the drivers of fiscal adjustments, expansions, and their duration. In contrast to most previous studies, the identification of these fiscal events relies on breaks in their data generating process. Our findings suggest that a few political and institutional variables play a role in determining the occurrence and the duration of fiscal adjustments and expansions. The results also highlight the importance of analyzing the likelihood of fiscal events together with their persistence. Factors that do not affect the occurrence of fiscal adjustments or expansions may influence their persistence once initiated.