A continuous global record of near-surface soil freeze/thaw status from AMSR-E and AMSR2 data

Long term and consistent records of near-surface soil freeze/thaw (F/T) status are required for understanding hydrological, ecological, and biogeochemical responses of land surface to global warming. To create such a record, we compiled and inter-calibrated satellite observations from the Advanced Microwave Scanning Radiometer – Earth Observing System (AMSR-E) and its successor, AMSR2, using linear regression models, and then applied a discriminant algorithm to the calibrated observations to map global F/T status from 2002 to 2018. The new global F/T dataset was rigorously assessed using in situ air and surface temperatures, and modelled soil temperature. Results show that agreement between remotely sensed F/T status and that determined by in situ or modelled temperature exceeds 85% and 79% for ascending and descending orbits, respectively. Moreover, consistency between the F/T datasets derived from two sensors is around 0.8 after calibration, in nonoverlapping time frames. With such an accuracy and consistency, we calculated frost days and frost trends using the F/T dataset. The mean annual number of frost days of high northern latitudes (>45° N) is 279.2 ± 44.1 days. Based on Mann-Kendall’s tau-b test, 7.7% of global lands show a significant warming trend, and most of which are concentrated in the Western United States, Northern and Eastern Canada, Northern Europe and Western China. Such a spatial distribution was found to be consistent with the global land surface temperature anomalies trend from 2002 to 2018. Both the results of applications and favourable accuracy indicate the potential of this long, consistent F/T record to track global temperature change.     

远程虚拟实验室的研究与开发

由于虚拟仪器(Virtual Instrumentation,VI)和网络技术的飞速发展,通过C/S或者B/S模式和虚拟现实技术来构建分布式虚拟教学系统的方法逐渐受到关注;文章介绍了利用现代教育技术把虚拟实验引入到实验教学中,构建完整的远程虚拟实验室系统化教学平台的解决方案;这个方法基于两种模式,软件共享模式和硬件共享模式,这两种模式结合虚拟现实技术能够最大限度利用现有软硬件资源和改善系统效率并降低建立系统的成本;这个最优化的解决方案应用到现代远程教育系统中,可提高教学质量和改善实验类型。     

Adapting on-line analytical processing for decision modelling: the interaction of information and decision technologies

The introduction of new technologies and concepts has redefined the relative positioning of information systems (IS) and decision technologies in a corporate context. Corporate IS have been extended to include not only transaction processing databases but also analytical databases, often known as Data Warehouses. On-line analytical processing (OLAP), as introduced by Codd et al. [E.F. Codd, S.B Codd, C.T. Salley, Providing On-Line Analytical Processing to User–Analysts: An IT Mandate, E.F. Codd and Associates, 1993], is capable of capturing the structure of the real world data in the form of multidimensional tables which are known as `datacubes' by management information systems (MIS) and statistical systems specialists. Manipulation and presentation of such information through multidimensional views and graphical displays provide invaluable support for the decision-maker. We illustrate the natural coupling, which exists between data modelling, symbolic modelling and `What if' analysis phases of a decision support system (DSS). In particular, we explore the power of roll-up and drill-down features of OLAP and show how these translate into aggregation and disagreggation of the underlying decision models. Our approach sets out a paradigm for analysing the data, applying DSS tools and progressing through the information value chain to create organisational knowledge.     

Commerce by Any Other Name

D.F. Aldrich, Mastering the Digital Marketplace: Practical Strategies for Competitiveness in the New Economy, New York, NY: Wiley (2000) 309 pp.

R. Kalakota and M. Robinson, e-Business: Roadmap for Success, Reading, MA: Addison-Wesley (1999) 378 pp.

R. Murch and T. Johnson, Intelligent Software Agents, Upper Saddle River, NJ: Prentice Hall PTR, (1999) 210 pp.

R. T. Watson, P. Berthon, L.F. Pitt, and G.M. Zinkhan, Electronic Commerce: the Strategic Perspective, Ft. Worth, TX: the Dryden Press (2000) 162 pp.

J. Christopher Westland and T.K.H. Clark, Global Electronic Commerce: Theory and Cases, Cambridge, MA: MIT Press (2000) 585 pp.     

Cartesian control of redundant robots

This article presents a Cartesian-space position/force controller for redundant robots. The proposed control structure partitions the control problem into a nonredundant position/force trajectory tracking problem and a redundant mapping problem between Cartesian control input F ? R ^m and robot actuator torque T ? R ⁿ(for redundant robots, m < n). The underdetermined nature of the F → T map is exploited so that the robot redundancy is utilized to improve the dynamic response of the robot. This dynamically optimal F → T map is implemented locally (in time) so that it is computationally efficient for on-line control; however, it is shown that the map possesses globally optimal characteristics. Additionally, it is demonstrated that the dynamically optimal F→T map can be modified so that the robot redundancy is used to simultaneously improve the dynamic response and realize any specified kinematic performance objective (e.g., manipulability maximization or obstacle avoidance). Computer simulation results are given for a four degree of freedom planar redundant robot under Cartesian control, and demonstrate that position/force trajectory tracking and effective redundancy utilization can be achieved simultaneously with the proposed controller.     

ABB工业IT AC800F控制系统在红塔滇西水泥厂的应用

本文介绍ABB工业IT系统在云南红塔滇西水泥厂中的应用，该系统采用AC800F控制器，基于TCP／IP协议以太网和ProfiBus-DP／PA现场总线的网络架构。作者详细描述了该控制系统的结构和配置、采用的新技术、调试及运行效果。     

Bidirectional Evolutionary Structural Optimization (BESO) based design method for lattice structure to be fabricated by additive manufacturing

Unlike traditional manufacturing methods, additive manufacturing can produce parts with complex geometric structures without significant increases in fabrication time and cost. One application of additive manufacturing technologies is the fabrication of customized lattice-skin structures which can enhance performance of products while minimizing material or weight. In this paper, a novel design method for the creation of periodic lattice structures is proposed. In this method, Functional Volumes (FVs) and Functional Surfaces (FSs) are first determined based on an analysis of the functional requirements. FVs can be further decomposed into several sub-FVs. These sub-FVs can be divided into two types: FV with solid and FV with lattice. The initial design parameters of the lattice are selected based on the proposed guidelines. Based on these parameters, a kernel based lattice frame generation algorithm is used to generate lattice wireframes within the given FVs. At last, traditional bidirectional evolutionary structural optimization is modified to optimize distribution of lattice struts’ thickness. The design method proposed in this paper is validated through a case study, and provides an important foundation for the wide adoption of additive manufacturing technologies in the industry.     

An optimal replacement period for a k-out-of-n: F system subject to shocks

A k-out-of-n: F system, which consists of n components and fails if at least k of the n components fail, is subject to shocks that arrive according to an inhomogeneous Poisson process. The k-out-of-n: F system is completely replaced (planned replacement) whenever it reaches age T (T > 0) at a fixed cost R₂. If the mth shock arrives at age S_m < T, it causes the simultaneous failure of j components at the same time with probability p_j     

嵌入式Linux下T1/E1网络接口设计与实现

使用T1／E1线路连接局域网对于实现网络互联以及安全保密通信具有重要的意义。讨论了嵌入式Linux下T1／E1网络接口的设计与实现，它是以太网桥开发中的重要部分，同时提到的一些技术对嵌入式Linux下的开发也具有很好的借鉴作用。     

一种新的H∞-优化方法:梯度方法

提出一种灵活、有效的H∞-优化方法:梯度方法.利用H∞-范数与状态空间实现的关系, 定义了目标函数ρ(ε,F),ρ(ε,F)与H∞-范数之间的关系是: limρ(ε,F)=1/‖T(s,F)‖∞ ε→0 分析了ρ(ε,F)的可微性,并给出了ρ(ε,F)/F的具体表达式以及使ρ(ε,F)极大化的梯 度方法,从而导致‖T(s,F)‖∞的极小化.实例表明,梯度方法能有效地使ρ(ε,F)上升,并 收敛于驻点或终止于不可微点.     

A novel non-volatile memory storage system for I/O-intensive applications

The emerging memory technologies, such as phase change memory (PCM), provide chances for highperformance storage of I/O-intensive applications. However, traditional software stack and hardware architecture need to be optimized to enhance I/O efficiency. In addition, narrowing the distance between computation and storage reduces the number of I/O requests and has become a popular research direction. This paper presents a novel PCMbased storage system. It consists of the in-storage processing enabled file system (ISPFS) and the configurable parallel computation fabric in storage, which is called an in-storage processing (ISP) engine. On one hand, ISPFS takes full advantage of non-volatile memory (NVM)’s characteristics, and reduces software overhead and data copies to provide low-latency high-performance random access. On the other hand, ISPFS passes ISP instructions through a command file and invokes the ISP engine to deal with I/O-intensive tasks. Extensive experiments are performed on the prototype system. The results indicate that ISPFS achieves 2 to 10 times throughput compared to EXT4. Our ISP solution also reduces the number of I/O requests by 97% and is 19 times more efficient than software implementation for I/O-intensive applications.     

On approximating contours of the piecewise trilinear interpolantusing triangular rational quadratic Bezier patches

Given a three dimensional (3D) array of function values F_i,j,k on a rectilinear grid, the marching cubes (MC) method is the most common technique used for computing a surface triangulation T approximating a contour (isosurface) F(x, y, z)=T. We describe the construction of a C⁰ continuous surface consisting of rational quadratic surface patches interpolating the triangles in T. We determine the Bezier control points of a single rational quadratic surface patch based on the coordinates of the vertices of the underlying triangle and the gradients and Hessians associated with the vertices     

On the complexity of purely complex μ computation and relatedproblems in multidimensional systems

In this paper, the following robust control problems are shown to be NP-hard: given a purely complex uncertainty structure Δ, determine if: 1) μ_Δ(M)<1, for a given rational matrix M; 2) ∥M(·)∥_μ<1, for a given rational transfer matrix M(s); and 3) inf(Q∈H^∞)∥F(T,Q)∥_μ<1, for a given linear fractional transformation F(T,Q) with rational coefficients. In other words, purely complex μ computation, analysis, and synthesis problems are NP-hard. It is also shown that checking stability and computing the H^∞ norm of a multidimensional system, are NP-hard problems. Therefore, it is rather unlikely to find nonconservative polynomial time algorithms for solving the problems in complete generality     

Fast solving method of fuzzy relational equation and itsapplication to lossy image compression/reconstruction

A fast solving method of the solution for max continuous t-norm composite fuzzy relational equation of the type G(i, j)=(R^T□A_i)^T□B_j , i=1, 2, ..., I, j=1, 2, ..., J, where A_i∈F(X)X={x₁, x₂, ..., x_M }, Bj∈F(Y) Y={y₁, y₂, ..., y_N}, R∈F(X×Y), and □: max continuous t-norm composition, is proposed. It decreases the computation time IJMN(L+T+P) to JM(I+N)(L+P), where L, T, and P denote the computation time of min, t-norm, and relative pseudocomplement operations, respectively, by simplifying the conventional reconstruction equation based on the properties of t-norm and relative pseudocomplement. The method is applied to a lossy image compression and reconstruction problem, where it is confirmed that the computation time of the reconstructed image is decreased to 1/335.6 the compression rate being 0.0351, and it achieves almost equivalent performance for the conventional lossy image compression methods based on discrete cosine transform and vector quantization     

Representations for semantic learning webs: Semantic Web technology in learning support

Abstract Recent work on applying semantic technologies to learning has concentrated on providing novel means of accessing and making use of learning objects. However, this is unnecessarily limiting: semantic technologies will make it possible to develop a range of educational Semantic Web services, such as interpretation, structure-visualization, support for argumentation, novel forms of content customization, novel mechanisms for aggregating learning material, citation services and so on. In this paper, we outline an initial framework that extends the use of semantic technologies as a means of providing learning services that are owned and created by learning communities.     

智能文本搜索新技术

面对当今互联网上海量的信息,以及搜索信息准确、高效、个性化等需求,提出了一套包括信息检索、信息抽取和信息过滤在内的智能文本搜索新技术.首先举荐了与信息检索新技术相关的企业检索、实体检索、博客检索、相关反馈子任务.然后介绍了与信息抽取技术相关的实体关联和实体填充子任务,以及与信息过滤技术相关的垃圾邮件过滤子任务.这些关键技术融合在一起,在多个著名的国际评测中得到应用,如美国主办的文本检索会议评测和文本分析会议评测,并且在互联网舆情、短信舆情和校园网对象搜索引擎等实际系统中得到了检验.     

Improved micro fluxgate sensor with double-layer Fe-based amorphous core

A rapid manufacturing process for the micro solenoid fluxgate sensor integrating multilayer amorphous ribbon core has been established, which combines the micro assembling method and the MEMS technologies. We select Fe-based amorphous soft magnetic ribbons for core materials and have fabricated the micro fluxgate sensors by MEMS technologies, with single-layer core and double-layer core respectively. The micro fluxgate sensors with double-layer core show the advantageous to that with single-layer core and exhibit sensitivity of 1089.2 V/T at excitation current of 120 mA rms, wide linear range of ?900 to 900 μT and power consumption of 24.48 mW. The noise power density of the single core fluxgate sensor is 2.48nT/Hz^1/2@1 Hz.     

Three‐dimensional printing technologies for terahertz applications: A review

Three‐dimensional (3D) printing technologies enables fast prototyping of complex 3D objects with ever improving printing qualities. To date, 3D printing has been found useful in areas such as manufacturing, industrial design, aerospace, dental and medical industries, and many others. In this article, we review recent advances of 3D printing technologies for terahertz (THz) applications. Different 3D printing technologies and printable materials are first discussed and compared. 3D‐printed THz components and devices, which are categorized as waveguides/fibers, antennas, and quasi‐optical components, are further demonstrated. It is found that the performances and functionalities of 3D‐printed THz devices have been greatly enhanced, while the operating frequencies have been increased from the lower end of THz range to over 1 THz region. With further development of novel materials and printing techniques, it is believed that 3D printing technologies will play an important role in the realization of THz components for efficient control and manipulation of THz waves.     

Large-scale coordination: developing a framework to evaluate socio-technical and collaborative issues

Collaborative logistics, logistics-based networks, focused logistics, and distributed adaptive logistics refer to innovative approaches to logistics planning/execution encompassing automated, adaptive technologies, and proactive human collaboration. Because these approaches are collaborative and distributed in nature, they create novel challenges for coordination and collaboration within socio-technical systems, which encompass the collaborative technologies, the people or machines engaged in collaboration, and the social context of collaboration and coordination. The present challenges need to be met by theoretical models incorporating multidisciplinary perspectives in the study of collaboration. The current paper introduces a collaboration framework which may inform the design and implementation of collaborative technologies and systems, to include distributed logistics teams, from a socio-technical perspective.     

A novel 3D cavity diplexer with compact size using LTCC technologies for V‐band wireless communication systems

In this article, a novel concept of 3D integrated V‐band diplexer, which permits the realization of compact size using a dual‐mode cavity and four single‐mode cavities, has been realized in low‐temperature cofired ceramic technologies. The dual‐mode cavity resonator acting as one resonator for both Rx and Tx filters is developed to generate two resonant modes (TE₁₀₂ and TE₁₀₃) at the center frequency of Rx (56.5–58.5 GHz) and Tx (64–66 GHz) channels, separately. Meanwhile, this dual‐mode cavity becomes the interconnect between Rx/Tx channels and help to realize good isolation without using conventional T‐junction. In the measurement, each filter designed for Rx and Tx channels exhibits excellent performance. Channel‐to‐channel isolations better than 35 dB across the Rx band and better than 32.5 dB across the Tx band are also obtained. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:141–145, 2015.