民族高校图书馆外文文献资源建设的几点思考

结合吉首大学图书馆外文采访工作的实际经验和体会,探讨了民族地区高校图书馆外文书刊采访工作面临的困境以及应对的方法和策略,并提出一些有益的建议。参考文献3。     

医学期刊质量和编辑水平的提高与循证医学的关系

通过循证医学与医学期刊及编辑关系重要性的论述 ,使医学期刊同人意识到未来循证医学对刊物质量及编辑水平的提高有着不可忽视的影响 ,并应在实际工作中遵循循证医学理论来编审稿件     

移天缩地,咫尺万里--评《数字信息资源的检索与利用》

评述了《数字信息资源的检索与利用》一书,认为该书是中国第一部真正意义上的数字信息资源检索与利用方面的指南性工具书,指出其对于培养读者的检索技能、提高其信息素养的重大价值。     

Vibration suppression and output constraint of a variable length drilling riser system

In this paper, we mainly concentrate on the control issue of a variable length drilling riser under condition of unknown disturbances and output constraint. The studied flexible drilling riser system with variable length, variable tension, variable speed and restricted boundary output is essentially a nonlinear distributed parameter system. For achieving the vibration suppression and ensuring the boundary output within the constrained range, an appropriate control scheme with output signal barrier is put forward by integrating boundary control method, barrier Lyapunov function with finite-dimensional backstepping technique, where disturbance observer is employed for coping with the boundary disturbance. Moreover, the Lyapunov’s synthetic method is applied for the steadiness research of the studied flexible drilling riser system, and the simulations are presented to display the usefulness of proposed control scheme.     

Necessary and sufficient criteria for asynchronous stabilization of Markovian jump systems

This paper is concerned with asynchronous stabilization for a class of discrete-time Markovian jump systems. The mode of designed controller is considered to be not perfectly synchronous with the activated mode of the Markovian jump system. In order to achieve the asymptotic stability with asynchronous controller, a conditional probability is introduced to describe the asynchronism of system and controller modes, which is dependent on the active system mode. Besides, due to the difficulty in acquiring all the mode transition probabilities in practice, the transition probabilities of the Markovian jump system and the controllers are supposed to be partially unknown. A necessary and sufficient condition is developed to guarantee the stochastic stability of the resultant closed-loop system and further extended to asynchronous stabilization with partially known transition probabilities. Finally, the effectiveness and advantages of the proposed methods are demonstrated by two illustrative examples.     

Spacecraft output feedback attitude control based on extended state observer and adaptive dynamic programming

This paper investigates spacecraft output feedback attitude control problem based on extended state observer (ESO) and adaptive dynamic programming (ADP) approach. For the plant described by the unit quaternion, an ESO is first presented in view of the property of the attitude motion, and the norm constraint on the unit quaternion can be satisfied theoretically. The practical convergence proof of the developed ESO is illustrated by change of coordinates. Then, the controller is designed with an involvement of two parts: the basic part and the supplementary part. For the basic part, a proportional-derivative control law is designed. For the supplementary part, an ADP method called action-dependent heuristic dynamic programming (ADHDP) is adopted, which provides a supplementary control action according to the differences between the actual and the desired system signals. Simulation studies validate the effectiveness of the proposed scheme.     

Adaptive neural design frame for uncertain stochastic nonlinear non-lower triangular pure-feedback systems with input constraint

This paper dedicates to dealing with the adaptive neural design problem for uncertain stochastic nonlinear systems with non-lower triangular pure-feedback form and input constraint. On the basis of the mean-value theorem, the pure-feedback structure is first transformed into the desired affine structure, and then the well-known backstepping technology is applied to construct the actual input signal of the controller. Although the considered system has a fairly complex structure, a new adaptive neural tracking controller design frame is established via the flexible application of radial basis function (RBF) neural networks’ (NNs’) structural characteristics. The proposed design frame guarantees the control objective of this paper can be achieved. Finally, a simulation example is given to further illustrate the availability of the proposed control scheme.     

Team diversity as dissimilarity and variety in organizational innovation

How team composition exactly influences innovation outcomes remains a complex and unsolved puzzle in the literature on creativity and innovation. Our study differentiates two types of team technology-related diversity—technological dissimilarity and technological variety, and investigates their influences on the impact of an invention created by a team. Analyses of over half million U.S. utility patents in the 1991–2005 period invented by teams reveal that technological variety of team inventors has a positive effect on invention impact, and that technological dissimilarity between team inventors plays both positive and negative roles, eliciting an inverted U-shaped effect. In addition, we find that the positive effect of dissimilarity is significantly reduced after controlling for variety. Theoretical and practical implications of our findings are discussed.     

无形技术外溢与区域自主创新——以桂林市为例的实证分析

通过构建R&D存量测算模型,对比分析区际贸易、投资和无形技术外溢对区域自主创新的影响机制,并以桂林市为例进行实证分析。研究发现：无形技术外溢短期内显著促进了桂林自主创新能力的提高,但长期看来则呈现负效应;区际贸易技术外溢对桂林自主创新的促进作用大于无形技术外溢;投资技术外溢未能显著促进桂林自主创新能力的提高。此外,桂林市R&D投资对其自主创新能力提升也起到了推动作用,虽然其贡献要小于区际贸易和无形技术外溢,但其正效应持续时间更长。     

海底观测网的研究进展与发展趋势

海底观测网是人类观测海洋的新型平台,可实现海洋由海底到海面的全天候、原位、长期、连续、实时、高分辨率和高精度观测,对海洋科学发展起到重要的支撑作用。美国、加拿大、日本以及欧洲各国凭借在海洋领域的先发优势,纷纷投入巨资构建海底观测网并成功运行。在现代传感器、水下机器人、海底光纤电缆、物联网、大数据等新型技术的推动下,海底观测网呈现综合性立体观测、数据深度发掘、多种观测计划综合交叉融合的发展趋势。