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1.
《Journal of The Franklin Institute》2022,359(15):8355-8376
For linear state space model, the covariance matrix setting errors of process and measurement noise deteriorate the estimation performance of Rauch–Tung–Striebel (RTS) smoother. To address this problem, the Markov Chain Monte Carlo is utilized to sample the state vector and noise covariance matrices simultaneously in this study. The Gibbs sampler is adopted and the corresponding adaptive RTS smoother is designed. Simulation results confirm the performance of proposed smoother. 相似文献
2.
《国家科学评论(英文版)》2014,(3)
The ecological water diversion project in the Heihe River Basin is the irst successful case in China in which the ecological systems in a river basin have been rescued. his project serves as a valuable example for the management of ecosystems in other inland river basins. his paper reviews the integrated studies of the water–ecosystem–economy relationship in the Heihe River Basin and concludes that sustainable development in inland river basins requires the basin to be considered as a whole, with the relationships between the upstream, midstream and downstream areas of the basin coordinated appropriately. Successful development in these basins will be relected in an improved output per cubic meter of water and the implementation of integrated river basin management practices. 相似文献
3.
Zhigang Ren Chao Xu Zhongcheng Zhou Zongze Wu Tehuan Chen 《Journal of The Franklin Institute》2019,356(1):173-195
In this paper, the boundary stabilization problem of a class of unstable reaction–advection–diffusion (RAD) systems described by a scalar parabolic partial differential equation (PDE) is considered. Different the previous research, we present a new gradient-based optimization framework for designing the optimal feedback kernel for stabilizing the unstable PDE system. Our new method does not require solving non-standard Riccati-type or Klein–Gorden-type PDEs. Instead, the feedback kernel is parameterized as a second-order polynomial whose coefficients are decision variables to be tuned via gradient-based dynamic optimization, where the gradients of the system cost functional (which penalizes both kernel and output magnitude) with respect to the decision parameters are computed by solving a so-called “costate” PDE in standard form. Special constraints are imposed on the kernel coefficients to ensure that the optimized kernel yields closed-loop stability. Finally, three numerical examples are illustrated to verify the effectiveness of the proposed approach. 相似文献
4.
Partnerships between business clients and vendors are increasingly becoming more common as firms strive to reduce cost and outsource non-core activities. Some firms proactively manage the knowledge gained from such partnership while others do so to a lesser extent. Through a questionnaire survey of business clients in Singapore, this study helps to shed some light on the nature of client–vendor partnership, factors affecting knowledge transfer (defined in terms of knowledge codifiability, client's motivation for partnership, vendor's willingness to share, and trust between client and vendor). In addition, we also examine mechanisms for knowledge dissemination within the client organization and the impact on the IT function. The results should be of interest to both researchers and practitioners in better understanding how such partnership could be managed more effectively. 相似文献
5.
Wulf Loh 《Ethics and Information Technology》2018,20(4):233-247
This paper distinguishes between two main questions regarding the notion of privacy: “What is privacy?” and “Why do/should we value privacy?”. In developing a social-ontological recognitional model of privacy (SORM), it gives an answer to the first question. According to the SORM, Privacy is a second order quality of roles within social practices. It is a function of who is or should be recognized as a “standard authority”. Enjoying standard authority means to have the right to interpret and contest role behavior and role obligations within a specific practice (first level), as well as evaluate the normative structure, the fundamental practice norms as well as the roles and their status (second level). The SORM utilizes the concept of standard authority to explicate privacy with regard to two categories that capture the relevant phenomena of privacy: decisional and informational privacy. Within a practice, an actor is said to have decisional privacy if she as a BCR does not (or does not have to) recognize bearers of accidental roles as standard authorities. Vice versa, an actor is said to enjoy informational privacy if all other BCRs (and especially data collecting actors) recognize her as a standard authority. Additionally, the requirement of mutual recognition by the practice participants as standard authorities introduces a “weak normativity” into the theory, which can be used to identify deficient privacy arrangements within practices. 相似文献
6.
To perform repetitive tasks, this paper proposes an adaptive boundary iterative learning control (ILC) scheme for a two-link rigid–flexible manipulator with parametric uncertainties. Using Hamilton?s principle, the coupled ordinary differential equation and partial differential equation (ODE–PDE) dynamic model of the system is established. In order to drive the joints to follow desired trajectory and eliminate deformation of flexible beam simultaneously, boundary control strategy is added based on the conventional joints torque control. The adaptive iterative learning algorithm for boundary control scheme includes a proportional-derivative (PD) feedback structure and an iterative term. This novel controller is designed to deal with the unmodeled dynamics and other unknown external disturbances. Numerical simulations are provided to verify the performance of proposed controller in MATLAB. 相似文献
7.
《Journal of The Franklin Institute》2023,360(6):4016-4030
In recent years, both the continuous-time and discrete-time Cucker–Smale models have been widely studied. However, in the practical systems, the dynamics of the agents coupled with each others can be hybrid. Thus, we consider the asymptotic flocking behavior of the hybrid Cucker–Smale model, which is composed of continuous-time dynamic agents and discrete-time dynamic agents. Firstly by some technical lemmas, a super-linear inequality of the derivative of velocity variance is established. Then, we eventually show that the hybrid model can achieve asymptotic flocking for the long-range communication weight1 case. At last, the simulation examples are given to verify the theoretical results. 相似文献
8.
《Information processing & management》2023,60(3):103280
Image and text matching bridges visual and textual modality differences and plays a considerable role in cross-modal retrieval. Much progress has been achieved through semantic representation and alignment. However, the distribution of multimedia data is severely unbalanced and contains many low-frequency occurrences, which are often ignored and cause performance degradation, i.e., the long-tail effect. In this work, we propose a novel rare-aware attention network (RAAN), which explores and exploits textual rare content for tackling the long-tail effect of image and text matching. Specifically, we first design a rare-aware mining module, which contains global prior information construction and rare fragment detector for modeling the characteristic of rare content. Then, the rare attention matching utilizes prior information as attention to guide the representation enhancement of rare content and introduces the rareness representation to strengthen the similarity calculation. Finally, we design prior information loss to optimize the model together with the triplet loss. We perform quantitative and qualitative experiments on two large-scale databases and achieve leading performance. In particular, we conduct 0-shot test for rare content and improve rSum by 21.0 and 41.5 on Flickr30K (155,000 image and text pairs) and MSCOCO (616,435 image and text pairs), demonstrating the effectiveness of the proposed method for the long-tail effect. 相似文献
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10.
《Information processing & management》2023,60(1):103155
This paper presents a continuous delivery/continuous verifiability (CD/CV) method for IoT dataflows in edge–fog–cloud. A CD model based on extraction, transformation, and load (ETL) mechanism as well as a directed acyclic graph (DAG) construction, enable end-users to create efficient schemes for the continuous verification and validation of the execution of applications in edge–fog–cloud infrastructures. This scheme also verifies and validates established execution sequences and the integrity of digital assets. CV model converts ETL and DAG into business model, smart contracts in a private blockchain for the automatic and transparent registration of transactions performed by each application in workflows/pipelines created by CD model without altering applications nor edge–fog–cloud workflows. This model ensures that IoT dataflows delivers verifiable information for organizations to conduct critical decision-making processes with certainty. A containerized parallelism model solves portability issues and reduces/compensates the overhead produced by CD/CV operations. We developed and implemented a prototype to create CD/CV schemes, which were evaluated in a case study where user mobility information is used to identify interest points, patterns, and maps. The experimental evaluation revealed the efficiency of CD/CV to register the transactions performed in IoT dataflows through edge–fog–cloud in a private blockchain network in comparison with state-of-art solutions. 相似文献
11.
从分子水平研究了PEO-PPO-PEO嵌段共聚物聚集过程中分子基团微环境和构象的变化。FTIR光谱给出了温度、溶剂、嵌段共聚物组成等影响PEO-PPO-PEO嵌段共聚物胶团结构的定量信息。用无机盐和脂肪醇调控PEO-PPO-PEO嵌段共聚物聚集，荧光光谱技术提供了降低PPO链段与水的相互作用，推动嵌段共聚物在水中胶团化的证据。用水凝胶包埋PEO-PPO-PEO嵌段共聚物，实现了萃取水中低浓度多环芳烃的工艺循环。 相似文献
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13.
Hamed Jabbari Asl Tatsuo Narikiyo Michihiro Kawanishi 《Journal of The Franklin Institute》2019,356(13):7144-7163
In this study, we addressed the problem of design of high-performance tracking controller for uncertain systems described by the Euler–Lagrange formulation. The main objective was to combine the advantages of the robust integral of the sign of the error (RISE) controller with those of the prescribed performance (PP) controller. In particular, we aimed to obtain asymptotic tracking for the uncertain systems through a continuous control command while ensuring the transient performance. Two controllers were developed. First, the PP property was injected into the RISE controller assuming no constraint on the actuation amplitude existed, and then this property was incorporated into the saturated RISE controller. The performance of the proposed controllers was validated through experimental and simulation tests. 相似文献
14.
Florian Szücs 《Research Policy》2018,47(7):1256-1266
We evaluate the impact of the EC's Seventh Framework Programme, a large-scale research subsidy programme, on the innovation activities of subsidized firms, with a particular regard to industry–university partnerships. Using matching and difference-in-difference estimation, we find a positive effect on a range of innovation indicators. The number of project participants in general and university participants in particular positively affect performance, suggesting knowledge spillovers between project members. Research centres, on the other hand, do not exert positive externalities. We also find that the benefits of collaborating with universities are amplified by their academic quality. 相似文献
15.
This paper investigates the distributed chattering-free containment control problem for multiple Euler–Lagrange systems with general disturbances under a directed topology. It is considered that only a subset of the followers could receive the information of the multiple dynamic leaders. First, by combining a linear sliding surface with a nonsingular terminal sliding manifold, a distributed chattering-free asymptotic containment control method is proposed under the assumption that the upper bounds of the general disturbances are known. Further, based on the high-order sliding mode control technique, an improved distributed chattering-free finite-time containment control algorithm is developed. Besides, adaptive laws are designed to estimate the unknown upper bounds of the general disturbances. It is demonstrated that all the followers could converge into the convex hull spanned by the leaders under both proposed control algorithms by graph theory and Lyapunov theory. Numerical simulations and comparisons are provided to show the effectiveness of both algorithms. 相似文献
16.
《Information processing & management》2022,59(1):102747
In information retrieval (IR), the improvement of the effectiveness often sacrifices the stability of an IR system. To evaluate the stability, many risk-sensitive metrics have been proposed. Since the theoretical limitations, the current works study the effectiveness and stability separately, and have not explored the effectiveness–stability tradeoff. In this paper, we propose a Bias–Variance Tradeoff Evaluation (BV-Test) framework, based on the bias–variance decomposition of the mean squared error, to measure the overall performance (considering both effectiveness and stability) and the tradeoff between effectiveness and stability of a system. In this framework, we define generalized bias–variance metrics, based on the Cranfield-style experiment set-up where the document collection is fixed (across topics) or the set-up where document collection is a sample (per-topic). Compared with risk-sensitive evaluation methods, our work not only measures the effectiveness–stability tradeoff of a system, but also effectively tracks the source of system instability. Experiments on TREC Ad-hoc track (1993–1999) and Web track (2010–2014) show a clear effectiveness–stability tradeoff across topics and per-topic, and topic grouping and max–min normalization can effectively reduce the bias–variance tradeoff. Experimental results on TREC Session track (2010–2012) also show that the query reformulation and increase of user data are beneficial to both effectiveness and stability simultaneously. 相似文献
18.
In this paper, we provide a new insight into clustering with a spring–mass dynamics, and propose a resulting hierarchical clustering algorithm. To realize the spectral graph partitioning as clustering, we model a weighted graph of a data set as a mass–spring dynamical system, where we regard a cluster as an oscillating single entity of a data set with similar properties. And then, we describe how oscillation modes are related with eigenvectors of a graph Laplacian matrix of the data set. In each step of the clustering, we select a group of clusters, which has the biggest number of constituent clusters. This group is divided into sub-clusters by examining an eigenvector minimizing a cost function, which is formed in such a way that subdivided clusters will be balanced with large size. To find k clusters out of non-spherical or complex data, we first transform the data into spherical clusters located on the unit sphere positioned in the (k−1)-dimensional space. In the sequel, we use the previous procedure to these transformed data. The computational experiments demonstrate that the proposed method works quite well on a variety of data sets, although its performance degrades with the degree of overlapping of data sets. 相似文献
19.
Distributed systems consist of interconnected, lower-dimensional subsystems. For such systems, distributed analysis and design present several advantages, such as modularity, easier analysis and design, and reduced computational complexity. A special case of distributed systems is when the subsystems are connected in a string. Applications include distributed process control, traffic and communication networks, irrigation systems, hydropower valleys, etc. By exploiting such a structure, in this paper, we propose conditions for the distributed stability analysis of Takagi–Sugeno fuzzy systems connected in a string. These conditions are also extended to observer and controller design and illustrated on numerical examples. 相似文献
20.
This paper proposes a new set of discrete orthogonal separable moments of fractional order, named Fractional Charlier–Meixner Moments (FrCMMs). The latter are constructed from fractional Charlier polynomials (FrCPs) and fractional Meixner polynomials (FrMPs) proposed in this paper. The proposed FrMPs are constructed algebraically using the spectral decomposition of classical Meixner polynomials and singular value decomposition (SVD). The proposed FrCMMs generalize the separable moments of Charlier–Meixner of integer order (CMMs). In addition, FrCMMs are characterized by the polynomial parameters and by the fractional orders of the two fractional kernel functions of Charlier and Meixner, which allows them to be used efficiently for different applications such as local and global image reconstruction and image watermarking. Based on the proposed FrCMMs, a new watermarking scheme for copyright protection of digital images in the transform domain is proposed where the watermark is embedded in the FrCMM coefficients leading to an efficient watermarking scheme in terms of imperceptibility, robustness and security. The performances of the proposed moments are evaluated and compared with discrete fractional moments existing in the literature and with classical separable moments of integer order. 相似文献