双平行线阵的快速一维DOA估计

针对传统子空间算法需要进行特征值分解或奇异值分解等复杂计算的问题，提出一种双平行线阵（Double Parallel Linear Array,DPLA）的快速一维波达方向（Direction of Arrival，DOA）估计算法。算法通过处理互协方差矩阵的第一列元素构造出等效的噪声子空间，再通过求根MUSIC（Multiple Signal Classification）算法得到DOA估计，有效避开了特征值分解或奇异值分解，降低了计算复杂度，提高了运算速度。仿真结果表明，该算法在提高了估计精度的同时减少了估计时间。     

沈阳城市周边耕地多功能评价

[目的]为探索城市化影响下城市周边耕地多功能的现状,分析其空间差异,为耕地保护及城市周边耕地发展提供参考。[方法]从耕地的生产、生态、社会和景观4个功能出发构建评价指标体系,利用熵权法确定指标权重,加权求和法计算单一功能和多功能值,并用ArcGIS进行空间分析,对沈阳城市周边50个乡镇(街道)的耕地多功能性进行综合评价。[结果](1)沈阳城市周边耕地的多功能性空间差异较为明显。生产功能远郊平原区最强,远郊山区和近郊区较弱;生态功能总体偏弱,个别乡镇较好;距离城市越远,社会功能越强;景观功能近郊区较强,远郊区较弱。(2)耕地的生态、社会和景观功能主要受距市中心距离的影响,生产功能受地形和距市中心距离的双重影响,而多功能则受地形、距市中心距离及各乡镇(街道)耕地主导功能等的综合影响。(3)沈阳城市周边的大多数耕地以农业生产为主导,景观文化功能整体相对较弱。近郊区耕地生态功能所占比重较大,但社会功能比重较小,远郊区则与之相反。[结论]沈阳城市周边耕地多功能性空间差异较为明显且不均衡,应科学规划城市周边耕地功能,优化空间布局,协调耕地各功能的关系,促进耕地多功能综合发展。     

Farmers’ attitude towards the policy of remediation during fallow in soil fertility declining and heavy metal polluted area of China

Numerous countries and regions face soil fertility decline and heavy metal pollution, and China implements a policy of remediation during fallow (PRF) to deal with such challenges. In this study, we examine the evolution of PRF and surveys of farmers’ attitudes in China. We present suggestions which can be used as reference for other countries and regions. The Chinese government implemented the policy of remediation during production (PRP) to control the heavy metal pollution of land in 2014. The effect was unsatisfactory due to the lack of cooperation amongst farmers. Therefore, the Chinese government implemented PRF in 2016. Our investigation of 247 farmers shows that farmers’ comprehensive assessment of PRF is positively influenced by the cognition of government implementation, the cognition of policy function and the evaluation of value perception, and the PRF still faces several problems, such as low cognitive level of policy function, incomplete regulations of supervision and poor supporting system. Hence, we suggest that government should educate and train farmers, improve the supervision and set up the supporting system of PRF.     

Rural Residential Land Transition in the Beijing-Tianjin-Hebei Region: Spatial-Temporal Patterns and Policy Implications

Rural residential land transition (RRLT) dominates rural land use transition. Therefore, analysing the laws of transition and differentiation of land use is not only the basis for the differential management of rural residential areas but key to the sustainable use of rural land. This study constructs a conceptual model of RRLT using multi-period remote sensing monitoring data based on a comprehensive index method, ArcGIS, and FRAGSTATS landscape pattern analysis, among others. It also analyses the characteristics of the transition extent, transition trend, transition morphology, and transition intensity of rural residential land in the Beijing-Tianjin-Hebei (BTH) region from 1980 to 2018. The results show that, from a vertical comparison of long time series, the transition extent is characterised by a process of ‘slow growth—expanding start—fast expansion—slowing down’; the transition trend is characterised by an increase in the amount of cultivated land occupied by rural residential land, followed by a large number of rural residential land is reclaimed as cultivated land; the transition morphology is characterised by an increase in mean patch size and degree of irregularity, as well as aggregation; and the transition intensity is characterised by fluctuations in the process of ‘small-scale reduction—small-scale growth—substantial growth—small-scale growth and reduction’. A horizontal comparison of counties in the BTH region reveals a long-lasting and active growth trend in transition extent and transition intensity in the Beijing-Tianjin region, and a gradually slowing trend in the areas around the region. The transition morphology features of the northwest Hebei region are more prominent, and show that the scale of rural settlements is small, the plaques fragmented and irregular, and the layout more scattered. The BTH region should formulate a differentiated transition direction for rural residential areas based on the different functional areas, and play into the agglomeration, scale, and synergy effects of urban agglomerations. It should also coordinate and improve the human–land relationship in rural areas, and construct an orderly and densely distributed pattern of urban and rural spatial development with a reasonable layout and complementary functions.     

Cultural distance and international trade in services: A disaggregate view

In this paper, we estimate the effect of “cultural distance” on bilateral trade in services. The measure of cultural distance we use is based on scores that reflect country averages of individuals’ attitudes towards inequality, self-orientation, competition, uncertainty, traditions, and indulgence. Controlling for standard ingredients of gravity equations, we show that an aggregate measure of cultural distance has a significantly negative effect on total bilateral services trade. Once we take a more disaggregate view, we find that the strength of this effect differs across various types of services and various aspects of cultural distance.     

Financial analyst coverage for U.S. firms facing foreign competition: Evidence from trade liberalization

This study examines financial analyst coverage for U.S. firms following an increase in foreign product market competition. To capture exogenous shocks to domestic firms' competitive environments, we exploit a quasi‐natural experiment from large import tariff reductions over the 1984 to 2005 period in the manufacturing sector. Using data for the years before and after large tariff reductions, our difference‐in‐differences analysis shows evidence of a significant decrease in analyst coverage for incumbent U.S. firms when they face greater entry threat from foreign competitors. We also find that analysts with less firm‐specific experience and less accurate prior‐period forecasts are more likely to stop following the domestic firm when foreign competition intensifies. Overall, the findings suggest that foreign product market competition from global trade liberalization is an important determinant of financial analysts' coverage decisions.     

Partial least squares structural equation modeling in HRM research

Abstract

Partial least squares structural equation modeling (PLS-SEM) has become a key multivariate analysis technique that human resource management (HRM) researchers frequently use. While most disciplines undertake regular critical reflections on the use of important methods to ensure rigorous research and publication practices, the use of PLS-SEM in HRM has not been analyzed so far. To address this gap in HRM literature, this paper presents a critical review of PLS-SEM use in 77 HRM studies published over a 30-year period in leading journals. By contrasting the review results with state-of-the-art guidelines for use of the method, we identify several areas that offer room of improvement when applying PLS-SEM in HRM studies. Our findings offer important guidance for future use of the PLS-SEM method in HRM and related fields.     

从迷信和禁忌谈中俄文化差异

迷信和禁忌是世界各民族共有的现象,中俄两个民族由于不同的历史发展、地理位置、风俗习惯、宗教信仰,从而产生了文化差异,形成了不同的文化规范,迷信和禁忌也各不相同.本文试对俄汉两个民族就几种具有代表性的迷信禁忌进行对比、分析,旨在为跨文化交际提供有益的参考.     

高校校园快递“校企双主体”运营模式研究

通过对高校校园快递现状及问题分析,构建快递服务中心"校企双主体"运营模式,从校企共建管理团队,共同制定规章制度,共同培养人才,互培共聘,共同经营管理,共享经营利润等方面阐述了"校企双主体"的内涵,对高校校企合作、人才培养、校园快递服务的提升具有指导性意义。