Do reductions in tick sizes influence liquidity?

On 4 December 1995, the Australian Stock Exchange reduced the minimum tick size for stocks priced below $A0.50 and stocks priced above $A10. We use this natural experiment to examine the impact of tick size reductions on liquidity. The present paper reports that although lower tick sizes generally lead to increased liquidity, this result is not universal. Stocks with larger relative tick sizes experience the greatest improvement in liquidity, while stocks with small relative tick sizes and low trading volume experience reduced liquidity. There is no change in order exposure as a result of the reduced tick sizes.     

采用数据扩展技术在OFDM系统中实现不等错误保护传输

本文提出了采用数据扩展技术在正交频分复用(OFDM)系统中实现不等错误保护(UEP)传输的自适应调制算法.利用原始数据符号传输特性相同的特点,分别研究了以提高信道容量为目标,功率一定,最大化传输速率的不等错误保护UEP算法;以及以用户需求为目标,传输速率一定,最小化总功率的不等错误保护UEP算法.这两种算法均可根据待传输数据的要求,保证不同优先级数据的不同传输质量和不同传输速率.仿真结果表明,最大化传输速率UEP算法可以在速率最大化的同时,保证传输质量要求;最小化总功率UEP算法可以在最小化发射功率的前提下,保证传输质量要求.与传统OFDM系统中相应算法的比较结果可以看出,采用数据扩展技术可以大大降低算法复杂度,减少有关调制参数信息的传输,在实现UEP时,在性能和复杂度之间具有较好的折中,具有较高的实际应用价值.     

非等间隔动态面板数据模型：估计方法与应用实例

非等间隔动态面板数据模型由于相邻两期观测之间的时间长度不尽相同使得传统动态面板数据模型的估计方法失效,本文提出使用非线性最小二乘、最短距离以及它们的一步估计量对该模型进行估计,证明了这四个估计量的一致性和渐进正态性,同时借助蒙特卡洛模拟的方法验证了它们在有限样本中的估计精度,并且进一步使用所提出的估计量讨论了以往文献由于缺乏相应的估计方法而没有被研究或者充分讨论的问题,得到了一些新的结论。     

Using machine learning and big data for efficient forecasting of hotel booking cancellations

Cancellations are a key aspect of hotel revenue management because of their impact on room reservation systems. In fact, very little is known about the reasons that lead customers to cancel, or how it can be avoided. The aim of this paper is to propose a means of enabling the forecasting of hotel booking cancellations using only 13 independent variables, a reduced number in comparison with related research in the area, which in addition coincide with those that are most often requested by customers when they place a reservation. For this matter, machine-learning techniques, among other artificial neural networks optimised with genetic algorithms were applied achieving a cancellation rate of up to 98%. The proposed methodology allows us not only to know about cancellation rates, but also to identify which customer is likely to cancel. This approach would mean organisations could strengthen their action protocols regarding tourist arrivals.     

Evaluating the impact of land fragmentation on the cost of agricultural operation in the southwest mountainous areas of China

Given the background of the increasing opportunity cost of farming and the popularization of labour-saving technology, increased fragmentation has gradually become a key factor in the devaluation and abandonment of land assets. To systematically identify the costs of fragmentation, we use a series of indicators such as the number of plots, the Simpson index, the plot-homestead distance and the total minimum commuting time from the homestead to all plots to measure the extent of fragmentation. A translogcost function is developed and estimated using survey data from three periods, 2011, 2014 and 2017; the data include an effective sample of 1064 household-year observations involving 6599 plot-year observations in Chongqing, China. The extent of fragmentation in the mountains of southwest China is quite serious compared with that in other countries and regions. The Simpson index is 0.63, and on average, 6.06 mu (1 mu = 666.67 m² or 1 mu = 1/15 ha) of cultivated land is distributed in 6.16 plots, while the total minimum commuting time from the homestead to all plots is approximately 45 min. An increase of one standard deviation in the number of plots, the Simpson index or total minimum commuting time would lead to cost increases of 7.1 %, 15.1 % and 12.2 %, respectively, if other conditions remain unchanged. The channel for the above result involves the changes in the cost share of inputs caused by fragmentation, which increase the labour cost share and reduce the machinery cost share. There is an inverted U-shaped relationship between farm scale and production cost with an inflection point at 47 mu; that is, costs begin to decrease when the scale exceeds 47 mu. However, the average farm scale is currently only 6.06 mu. In addition, production costs can be significantly reduced by renting-in land and implementing land consolidation. To reduce land system-induced costs in mountainous areas, the government should rationally consolidate land to achieve moderate-scale management, reduce the transaction costs of land transfers and popularize machinery suitable for complex terrain.     

Research on a stock-matching trading strategy based on bi-objective optimization

In recent years, with strict domestic financial supervision and other policy-oriented factors, some products are becoming increasingly restricted, including nonstandard products, bank-guaranteed wealth management products, and other products that can provide investors with a more stable income. Pairs trading, a type of stable strategy that has proved efficient in many financial markets worldwide, has become the focus of investors. Based on the traditional Gatev–Goetzmann–Rouwenhorst (GGR, Gatev et al., 2006) strategy, this paper proposes a stock-matching strategy based on bi-objective quadratic programming with quadratic constraints (BQQ) model. Under the condition of ensuring a long-term equilibrium between pairedstock prices, the volatility of stock spreads is increased as much as possible, improving the profitability of the strategy. To verify the effectiveness of the strategy, we use the natural logs of the daily stock market indices in Shanghai. The GGR model and the BQQ model proposed in this paper are back-tested and compared. The results show that the BQQ model can achieve a higher rate of returns.     

Holdup in oligopsonistic labour markets - a new role for the minimum wage

We consider a labour market model of oligopsonistic wage competition and show that there is a holdup problem although workers do not have any bargaining power. When a firm invests more, it pays a higher wage in order to attract workers from competitors. Because workers participate in the returns on investment while only firms bear the costs, investment is inefficiently low. A binding minimum wage can achieve the first-best level of investment, both in the short run for a given number of firms and in the long run when the number of firms is endogenous.     

Commodity price stabilisation: macroeconomic impacts and policy options

A macroeconometric simulation study is undertaken to evaluate the impact of commodity price stabilisation (CPS) schemes for the export tree crop industry in Papua New Guinea. The findings suggest that there is a negligible level of favourable macroeconomic impacts of CPS. Contrary to the expectation, CPS adversely affects the stability of monetary and external sectors (BOP). CPS policy has failed to stabilise the macroeconomy. The price stabilisation policies are no longer appropriate from the macroeconomic point of view. Technical change, futures market and rural savings are the possible alternative policy options to manage the price risk.     

互联网背景下共享型领导对团队创造力的促进作用研究:边界行为视角

互联网改变了人与人之间以及企业与企业之间的关系。创造力成为企业适应互联网时代的关键。基于边界理论视角,尝试从团队层面揭示互联网背景下共享型领导对团队创造力的促进作用。以北京和乌鲁木齐等地的30家企业128个团队共510位成员为样本,运用结构方程模型对样本数据进行分析,结果表明:共享型领导对团队创造力有显著正向影响;边界强化和边界缓冲行为在共享型领导和团队创造力之间起部分中介作用,尤其是边界跨越行为通过边界强化行为和边界缓冲行为对团队创造力起作用。研究结论为认识互联网时代团队创造力提供了新视角。     

基于树图的知识密集型服务组织的知识结构建模分析

从知识结构的视角,探析知识密集型服务组织的核心能力来源。在界定知识密集型服务组织的基础上,基于树图的表示方式建立知识密集型服务组织的知识结构模型,为进一步研究知识密集型服务组织的知识结构对其核心能力的支撑作用作基础。