Object-based,multi-sensor habitat mapping of successional age classes for effective management of a 70-year secondary forest succession

Multi-temporal change detection over decades including the pre-satellite era is challenging due to the different image types available over time, and this explains the scarcity of long-term studies of vegetation succession which can play a pivotal role in the restoration of biodiversity in regenerating forests. This study describes a semi-automated, object-based habitat classification method for change detection of tropical forest succession since 1945. The study uses a set of black and white aerial photographs and high-resolution satellite images which differ in quality and resolution, to investigate forest successional patterns and their implications for informed ecosystem and land rehabilitation management. For optimized habitat boundary delineation from black and white aerial photographs and panchromatic satellite images, three levels of hierarchical image object primitives were created. The minimum object sizes of 50 m², 500 m², and 1000 m² maximized inter-object and minimized intra-object variability according to the scale of habitat patches and imagery used. Object-Based Image Analysis (OBIA) provided additional Grey-Level Co-occurrence Matrix (GLCM) textural features of segmented objects which helped to incorporate knowledge-based rule-sets into the final habitat classification which was done manually. Results show accuracies for grassland greater than 94%, monoculture plantations were distinguished from natural forest with 95% accuracy, and isolated mature stands of natural forest achieved 75% accuracy. Consideration of multi-date images increased the accuracy of distinguishing between mixed plantations and natural forest as well as between shrubland and young secondary forest. The resulting maps of vegetation structure at five time periods from 1945 to present gave new insights into the ecological processes of secondary forest succession. These include the surprising rapid rate of natural forest regeneration, at an annual rate of 7.7% from 1945 to 2014, and an even faster rate of 11% during a period when hill fires were controlled. The last areas to succeed to forest are those which are still, or at some time have been under exotic mono-cultural plantations. This suggests that long term protection from hill fire would be a better option for assisting natural succession in the landscape than plantations, which are both costly, and act as barriers to natural succession. Overall, with more than 92% mapping accuracy, the method can be adapted for other multi-temporal, multi-sensor studies as it enables inclusion of spatial theories by dividing the satellite image into time-consistent geographic entities according to the scale of target objects and image resolution. The accurate maps of forest cover patches at different successional stages can also help in site specific management of the recovering forest, such as introduction of shrub seedlings to bridge bottlenecks in seed dispersal according to shrub density and dispersal distances for forest birds. Late successional tree species can also be introduced in areas where only early successional species are present after 50 years of succession.     

构建航运服务业CBD-我国港口发展新趋势

随着全球经济一体化进程加快,港口在现代物流中的核心作用越来越明显,突破传统的运输中转功能,构建航运服务业CBD,提供快捷、可靠、灵活的综合物流服务,已成为现代港口发展新趋势。结合中国港口建设,探讨了构建中国特色航运服务业CBD的策略。     

A multi-dimensional Bühlmann credibility approach to modeling multi-population mortality rates

In this paper, we first propose a multi-dimensional Bühlmann credibility approach to forecasting mortality rates for multiple populations, and then compare forecasting performances among the proposed approach, the CBD model, the Lee-Carter model (LC), the joint-k (JoK-LC), the co-integrated (CoI-LC), and the augmented common factor (ACF-LC) Lee-Carter models for multiple populations. Mortality data from the Human Mortality Database are fitted to the underlying mortality models for both genders of three well-developed countries (the US, the UK, and Japan) and both genders of a developed country (France) and a developing country (Poland) with an age span 25–84 and a wide range of fitting year spans. Empirical illustrations show that the proposed multi-dimensional Bühlmann credibility approach contributes to more accurate forecast results, measured by AMAPE (average of mean absolute percentage errors over all fitting year spans), than the CBD, LC, JoK-LC, CoI-LC and ACF-LC models for three forecasting year spans 2004–2013 (10-year wide), 1994–2013 (20-year wide) and 1984–2013 (30-year wide).     

股票市场开放与企业投资效率——基于“沪港通”的准自然实验

资本市场的持续对外开放是党的十九大强调的重要举措。本文基于沪港通开通这一准自然实验,检验了股票市场开放对企业投资效率的影响。结果发现:沪港通的开启促进了标的公司投资效率的提高,这一影响主要体现在信息环境不透明、治理水平低的公司;机制分析发现,沪港通开启后,公司信息质量的提高和分析师预测准确度的增加是股票市场开放影响标的公司投资效率的重要渠道;最终标的公司在沪港通开通后经营业绩也得到提升。本文结论表明,股票市场开放改善了公司的投资效率,提高了对实体经济的服务能力,这对党的十九大提出的“深化资本市场对外开放”和“金融服务实体经济”系列改革有重要启示。     

“港股直通车”对两地股市影响的实证分析

本文以股权分置改革后的最新数据为研究对象,首先剖析了香港股市与内地股市的高度关联性,然后运用计量经济方法检验两地股市的相关性、以及“港股直通车”前后两地股市关系发生的变化,从而得出结论：在当前背景下,不宜推出“港股直通车”。这也证明了中央暂停港股直通车的合理性与及时性。     

香港"夹心阶层住屋计划"经验借鉴

夹心阶层住屋计划是香港实施的第一个面向中等收入家庭的住房补贴政策。本文分析了其实施背景,借鉴其住房建设、管理与实施经验。针对当前大陆部分城市住宅市场中存在的问题,提出大陆解决夹心阶层住房困难的建议。     

《红楼梦》英译本人物对话的宏观语篇和语域重构

由于英汉两民族各自独特的文化背景、价值观念、思维方式、语言逻辑,造成了翻译中的各种语篇重构现象。《红楼梦》的两个英译本(杨宪益译本和霍克斯译本),因不同翻译策略的运用,使译文语篇发生重构,产生与原文在结构上的差异,较好地传递了原文的语用信息和内涵。     

资本市场开放与会计信息可比性——来自“沪港通”的经验证据

以2014年“沪港通”的实施作为外生事件，基于双重差分模型实证检验“沪港通”政策对于会计信息可比性的影响。研究发现：“沪港通”政策的实施显著提升了上市公司会计信息的可比性；“沪港通”政策通过公司治理机制提高了上市公司会计信息的可比性。“沪港通”政策对于提高我国资本市场的会计信息质量具有一定的积极作用，为我国后续资本市场进一步对外开放提供了经验证据。     

Family Business Succession in Hong Kong: The Case of Yung Kee

This case study examines the succession of Chinese family business in Hong Kong, drawing upon theories of the firm. More specifically, it utilizes capabilities theories, property rights economics and Neo-Confucianism to understand management disputes and infighting among the members in a Chinese family business in Hong Kong. This paper will argue that the founder of a Chinese business firm in Hong Kong is able to lead his or her offspring to create a dynamic enterprise via charismatic leadership and family rules embedded in traditional Chinese values. However, these two strategic assets disappear following the passing away of the founder as well as the emergence of new social values. When the founder passes on the enterprise to his or her offspring using more or less the equal inheritance system, the traditional Chinese value is unable to enforce the leader’s will to consolidate the strengths of the second generation family members to maintain the founder’s business. Furthermore, when the business is owned by all family members, property rights of the firm become unclear. Without effective enforcement of traditional Chinese values and with collective ownership rights, some family members will have the incentive to capture the economic rent that is shared by all members. In other words, some family members behave opportunistically or even cheat in order to capture economic gains in the public domain. High monitoring and enforcement costs in the form of court battle and endless disputes will occur. Rent dissipation occurs in the form of deterioration of the quality of the family business. This case study is based on Yung Kee, an internationally well-known roast goose restaurant in Hong Kong as an illustration.     

The impact of reporting frequency on the information quality of share price: evidence from Chinese state-owned enterprises

As a major global exchange, the Stock Exchange of Hong Kong (SEHK) only requires semi-annual reporting whereas other major exchanges including the ones in Chinese mainland require quarterly reporting. We argue against the traditional view that higher reporting frequency is necessarily more beneficial. The decision on reporting frequency depends on how the information is being processed by the recipient traders and the results are not obvious. Using a sample of Chinese companies duallisted in both China A share market and SEHK (AH shares) as the experimental group and mainland’s companies listed on SEHK (H shares) only as the control group, we apply the difference-in-difference (DID) method to investigate the impacts of reporting frequency on stock information quality. The results suggest that after China A share market require quarterly financial reporting for all listed companies in 2002, the information asymmetry of the H tranche of AH stocks increases. Different from prior studies, the results suggest a negative association between stock information quality and financial reporting frequency. We argue that the increased information asymmetry in the H tranche is caused by the noise spilled over from the A tranche. We conduct multivariable GARCH tests and find evidence supporting this conjecture.