A Simple Control Strategy Based on Trajectory Planning for Vertical Acrobot

This paper presents a simple control method on the basis of the trajectory planning for vertical Acrobot to accomplish the control goal of moving the system from the downward initial position (DIP) and steadying the system at the upward target position (UTP). First, for the active link, we frame a trajectory that contains some adjustable parameters. Along the framed trajectory, we can make the active link stabilize at its end angle from its start angle. Furthermore, we change the trajectory parameters to make the passive link also arrive at the zone near the end angle. Next, we devise a PD-based tracking controller to track this planned trajectory. In this way, the vertical Acrobot is swung up to a small zone near the UTP. Then, from the approximate linear model at the UTP, we devise a stabilization controller to stabilize the vertical Acrobot at the UTP. Finally, we implement the simulation to show the validity of the proposed method.

ALPINE: Active Link Prediction Using Network Embedding

Many real-world problems can be formalized as predicting links in a partially observed network. Examples include Facebook friendship suggestions, the prediction of protein–protein interactions, and the identification of hidden relationships in a crime network. Several link prediction algorithms, notably those recently introduced using network embedding, are capable of doing this by just relying on the observed part of the network. Often, whether two nodes are linked can be queried, albeit at a substantial cost (e.g., by questionnaires, wet lab experiments, or undercover work). Such additional information can improve the link prediction accuracy, but owing to the cost, the queries must be made with due consideration. Thus, we argue that an active learning approach is of great potential interest and developed ALPINE (Active Link Prediction usIng Network Embedding), a framework that identifies the most useful link status by estimating the improvement in link prediction accuracy to be gained by querying it. We proposed several query strategies for use in combination with ALPINE, inspired by the optimal experimental design and active learning literature. Experimental results on real data not only showed that ALPINE was scalable and boosted link prediction accuracy with far fewer queries, but also shed light on the relative merits of the strategies, providing actionable guidance for practitioners.

active link

File-1-active-link.pdf

Hybrid Control of a Pendubot System Using Nonlinear H∞ and LQR

In this paper, a hybrid control approach is synthesized for stabilizing an under-actuated mechanical system, the Pendubot. This kind of system is divided into two modes, the swing-up mode, and the balancing mode. First, dynamic modeling is established by the Euler-Lagrange method. Next, the robust nonlinear H∞ is designed for the swing-up mode, which handles with the nonlinear model. To weaken the under-actuation characteristic, the control law is developed for the active link with its coupling with the passive link. The LQR is designed for the balancing mode where LQR handles with the linearized model about the unstable top equilibrium position. A simulation is achieved under the MATLAB/Simulink environment. It shows robustness against the external inputs and the fast convergence to the equilibrium position.

City and Video Games: Moving Towards Each Other

The article is devoted to the problem of the city new imagery, the steady convergence of real architecture and virtual architecture. Although the connection between these phenomena has been the subject of reflection by specialists from various science branches for the past decades, it has not been sufficiently manifested. Another attempt at manifestation is made in this article, within the fundamental problems of art theory and history. Its novelty consists in activating the classical category “image of the city” in the virtual space centre of video games as the most active link between artistic and empirical images of the city. On the example of real architectural objects in the cities of the last quarter of the 20th — 21st centuries and architectural objects, existing only in the popular video games locations of the last generation, the interaction mechanisms of artistic images and their transition into the empirical images sphere with a gradual blurring of the transition boundaries are studied. The contemporary architecture trend is seen as the purposeful programming of sophisticated associative games through the production of images of the city that make you doubt the reality of the world, the difference between authenticity and imaginary. In turn, cities in video games simulate the same dubiously humane worlds, only in addition they can be managed, tested for viability online. The exacerbation of gaming in architecture is seen as a postmodern provocation to critically, ironic deconstruct reality in the fullness of its contradictions, and the videogame set of cities as an ideal platform to work on the deconstruction experience and, perhaps, to reset personal relationships with the world. It shows how the artistry of video games turns into the everyday background of life, changing the perception of the urban environment and the world as a whole.

A crisis of understanding and threats to the future

The article considers issues related to the crisis of understanding as the key pillar and basis of all other crises. It is proposed to consider the "infology" approach as a primary antidote to obtain a more adequate understanding of the world. This approach can make it possible to educate a new type of person such as homo informationalis, that is an active link in the information world.

Distributed link scheduling in wireless networks

This work investigates distributed transmission scheduling in wireless networks. Due to interference constraints, “neighboring links” cannot be simultaneously activated, otherwise transmissions will fail. Here, we consider any binary model of interference. We use the model described by Bui et al. in [L. X. Bui, S. Sanghavi and R. Srikant, Distributed link scheduling with constant overhead, IEEE/ACM Trans. Netw. 17(5) (2009) 1467–1480; S. Sanghavi, L. Bui and R. Srikant, Distributed link scheduling with constant overhead, in Proc. ACM Sigmetrics (San Diego, CA, USA, 2007), pp. 313–324.]. We assume that time is slotted and during each slot there are two phases: one control phase in which a link scheduling algorithm determines a set of non-interfering links to be activated, and a data phase in which data is sent through these links. We assume random arrivals on each link during each slot, so that a queue is associated to each link. Since nodes do not have a global knowledge of the queues sizes, our aim (like in [L. X. Bui, S. Sanghavi and R. Srikant, Distributed link scheduling with constant overhead, IEEE/ACM Trans. Netw. 17(5) (2009) 1467–1480; S. Sanghavi, L. Bui and R. Srikant, Distributed link scheduling with constant overhead, in Proc. ACM Sigmetrics (San Diego, CA, USA, 2007), pp. 313–324.]) is to design a distributed link scheduling algorithm. To be efficient, the control phase should be as short as possible; this is done by exchanging control messages during a constant number of mini-slots (constant overhead). In this paper, we design the first fully distributed local algorithm with the following properties: it works for any arbitrary binary interference model; it has a constant overhead (independent of the size of the network and the values of the queues), and it does not require any knowledge of the queue-lengths. We prove that this algorithm gives a maximal set of active links, where for any non-active link there exists at least one active link in its interference set. We also establish sufficient conditions for stability under general Markovian assumptions. Finally, the performance of our algorithm (throughput, stability) is investigated and compared via simulations to that of previously proposed schemes.