高分1号冬小麦解译面积核算方法研究

[目的]以高分1号(GF-1)融合2m卫星遥感影像为基础数据源,结合土地利用现状数据、高分多源遥感影像和地面样方等数据,对冬小麦分类提取中存在的面积误差问题进行研究和分析。[方法]文章以河南省永城市为研究区,在冬小麦提取结果聚类处理基础上,基于线性地物缓冲区数据,采用GIS空间运算实现线性地物面积扣除,接着分析了样方数据和土地利用现状数据再扣除零星地物面积比例上的差异,并采用样方零星地物平均扣除系数对全市各乡镇耕地与非耕地中冬小麦提取面积进行了相关统计和误差分析。[结果]永城市冬小麦最终解译面积11. 29万hm~2,其中线性地物和零星地物扣除面积分别为6 613. 08hm~2和3 875. 22hm~2,占研究区冬小麦解译面积的5. 86%和3. 32%,与统计上报数据相比,其处理前后误差由14. 12%降低至4. 41%,有效地提高冬小麦提取面积精度。[结论]误差来源分析与修正对冬小麦解译面积核算精度具有重要影响,该研究为县级区域尺度下冬小麦面积提取核算提供了思路和借鉴。     

Can investors time their exposure to private equity?

Private equity performance, both for buyouts and venture capital, has been highly cyclical: periods of high fundraising have been followed by periods of low performance. Despite this seemingly predictable variation, we find modest gains, at best, to pursuing realistic, investable strategies that time capital commitments to private equity. This occurs, in part, because investors can only time their commitments to funds; they cannot time when commitments are called or when investments are exited. There is a high degree of time-series correlation in net cash flows even across commitment strategies that allocate capital in a very different manner over time.     

A Real Options Model of Real Estate Development with Entitlement Risk

Most development projects encounter a highly uncertain entitlement process that is largely uncontrollable by developers. In this study, entitlement is modeled as a separate stage within a compound real option, where developers begin with minimal control (maximum risk) and each successful stage increases control (decreases risk). We solve the model analytically, provide three‐dimensional numerical comparisons, and empirically test the model's predictions using hand collected rezoning petitions. Our main result refines the classic development option model: developers first invest early (secure entitlements) in order to obtain the option to subsequently delay investment (construct the optimal building at the optimal time).     

COVID-19 and business renewal: Lessons and insights from the global airline industry

The emergence of the COVID-19 pandemic has adversely affected the fortunes of multiple companies around the globe. Accordingly, questions are increasingly being asked about how organizations can revitalize during and after a crisis. Yet, we have limited understanding of how organizations renew themselves during crises over time. We explore this question through the lens and examination of two South-Asian airlines: Pakistan International Airlines and Sri Lankan Airlines. The cases offer important insights into the reasons behind underperformance of state-controlled enterprises and renewal activities. We shed light on strategic renewal (SR) in the wake of increasing liberalization and deregulations in the global airline industry. To this end, we propose a four-stage approach towards renewing such underperforming organizations to respond effectively to black swan events and external shocks.     

Excess perks in SOEs: evidence from China

In investigating the relationship between economic directors (EDs) and excess perks in state-owned enterprises (SOEs) in China, we find a U-shaped relationship between the share of EDs on boards and excess perks, especially in SOEs controlled by local governments and with greater managerial power—as well as in regions with poor legal systems. The share of EDs on boards may have three benefits with respect to reducing the use of excess perks in SOEs: (1) replacing excess perks with monetary wages more aligned with the value of managers; (2) reducing the increase in excessive perks caused by the availability of free cash flow; and (3) reducing the use of excess employees to drive excess perks.     

Entry limiting agreements: First‐mover advantage,authorized generics,and pay‐for‐delay deals

During patent litigation, pay‐for‐delay (P4D) deals involve a payment from a patent holder of a branded drug to a generic drug manufacturer to delay entry and withdraw the patent challenge. In return for staying out of the market, the generic firm receives a payment, and/or an authorized licensed entry at a later date, but before the patent expiration. We examine why such deals are stable when there are multiple potential entrants. We combine the first‐mover advantage for the first generic with the ability of the branded manufacturer to launch an authorized generic (AG) to show when P4D deals are an equilibrium outcome. We further show that limiting a branded firm's ability to launch an AG before entry by a successful challenger will deter such deals. However, removing exclusivity period for the first generic challenger will not.     

继续为多边贸易体制贡献中国力量

入世20年来,中国切实履行入世承诺,逐步从多边贸易体系的学习者、参与者成长为关键角色.中国经济的快速发展得益于多边贸易体系和经济全球化的深度发展,中国独特的经济体制与结构,为WTO以及多边贸易体系的稳定发展提供了源源不断的动力,为全球经济贸易发展注入持久动能,为发展中经济体参与多边贸易体系作出积极贡献.当前,经济全球化迈向新阶段,呈现出许多新的特征,而WTO本身也发生了结构性变化.中国作为推动WTO改革进程、权力结构调整和利益分配的关键力量,在坚定自身立场的同时,应及时顺应全球化变化,积极响应多边贸易治理新需求,为WTO改革贡献中国智慧、中国方案、中国力量,推动多边贸易体系行稳致远.     

经济带:新发展阶段的新愿景

经济带已成为承东启西、连南贯北的"经济主骨架",在国民经济整体格局中的战略地位日益凸显,对我国经济发展具有重大战略意义.经济带的形成有其深刻的理论基础和现实条件,我国"两横"——长江经济带和陇海兰新经济带,以及"三纵"——沿海经济带、京广京哈经济带、包昆经济带五条经济带,需要进一步集聚经济要素,破除要素流动壁垒,提升节点城市能级,推动区域经济合作,以经济带建设推动我国经济高质量发展.