120 research outputs found
A meta-analysis on the effect of board characteristics on corporate financial performance
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Interacting with light apps and platforms
No full textIn the near future, highly dynamic light sources will be embedded in the areas in which we live and work, as well as in the objects within these areas. Furthermore, all these light elements will be connected, and digitally controlled. We believe that this development will turn our environments into lighting platforms that will not only allow us to see our surroundings and perform our tasks, but that will support many other functions and activities. This vision requires us to rethink the way we interact with light
Non-linear model predictive control for constrained mobile robots
No full textAn application of Non-Linear Model Predictive Control (NLMPC) to the stabilisation of a kinematic model of a two wheel mobile robot with input and (non-holonomic) state constraints is studied. Since linear (and even successively linearised or time-variant) MPC is not feasible for this mechanical benchmark problem (as the linearisation around any fixed point is not controllable and the assumptions for guaranteed stability with stability constraints fail), the potential of non-linear predictive control techniques is investigated. The NLMPC implementation is discussed and results are presented for several configurations. The expense and reliability of the non-convex optimisation causes problems. Tuning of the controller parameters appears to be decisive. In general, terminal state constraints are required to guarantee asymptotical stability. In this paper, these constraints are, analogous to the linear case, replaced by time-varying (exponential) weightings which are easier to handle. The results for the newly proposed non-linear control scheme are very promising, including improved convergence rates. The advantages of predictive control (constraint handling) are fully exploited. Still, the excessive computational demands make real-time implementation almost impossible and stability and robustness issues need to be further investigated
Layered protocols approach to analyze haptic communication over a network
No full textA layered protocols interaction model to describe haptic communication between two persons over a network is presented. This approach allows to consider all aspects of the haptic communication process: the intention to do an action, limitations of the human body, the communication device, and the network. The goal of the model is threefold, firstly it is a tool to identify problems and opportunities in existing haptic interaction projects, secondly it directs to solution areas of these problems and opportunities, and thirdly it aids to propose design guidelines for new devices for haptic interaction. We show that the model can be used during the synthesis of devices. As a first step in this process, existing communication devices are being analyzed and classified. Their strong and weak points are identified and linked to signals in the model. In the future, this should result in a set of design guidelines for haptic communication devices
The stress ulcer syndrome
Get PDFThe stress ulcer syndrome is described in this thesis. This
syndrome is seen in patients admitted to intensive care departments or
being treated in field hospitals, in disaster areas, or battle fields.
Acute mucosal lesions associated with burns (Curling's ulcers) and
central nervous system disorders (Cushing's ulcers) appear to have a
different pathophysiology and a different pathology to the real stress
ulcers.
Peptic ulcers and gastric lesions following use of non-steroidal
anti-inflammatory agents also differ from stress ulcers.
In chapter 2 the pathology of the stress ulcer is described. The
true stress ulcer is usually found in the proximal part of the
stomach, although it may rarely be seen in the distal part of the
stomach or in the small or large bowel. Erosions are also included in
the term stress ulcer. Histologically these are superficial defects
which seldom reach the muscularis propria
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