Adaptive structures in civil engineering are mechanical structures with the ability to modify their response to external loads. Actuators strongly affect a structure’s adaptivity and have to be placed thoughtfully in the design process to effectively compensate external loads. For constant loads, this property is introduced as steady-state disturbance compensability. This property can be linked to concepts from structural engineering such as redundancy or statical indeterminacy, thus representing an interdisciplinary approach. Based on the disturbance compensability matrix, a scalar performance metric is derived as quantitative measure of a structure’s ability to compensate the output error for arbitrary constant disturbances with a given set of actuators. By minimizing this metric, an actuator configuration is determined. The concept is applied to an example of a truss structure.

BackgroundLaparoscopic surgery (LS) induces physical stress to the surgeon that is associated with an increased prevalence of musculoskeletal pain and injury in the shoulder–neck region. The aim of this research project is to develop an arm support system (ASsyst) that reduces physical stress and is applicable to various laparoscopic interventions and operation room settings.MethodsA systematic approach to develop an ASsyst started in October 2012 consisting of five consecutive steps. In step 1, 14 laparoscopic interventions were observed using subjective and objective measures to determine key indicators for the conception of an ASsyst in LS. In step 2, an expert workshop was held to find and evaluate solutions to generate concepts for a support system based on the results of step 1 and general methods. During the third step, prototypes of ASsyst were tested in an experimental setting. Steps 4 and 5 are currently in process and include the final development of the ASsyst using the most promising concept for the evaluation during simulated LS.ResultsIncreased levels of physical stress were found in LS. Asymmetric strains were common. Three prototypes of ASsyst emerged from step 1 and 2. These prototypes were a cable construction with a noose for the lower arm, a support from below the elbow and a pneumatic vest supporting the upper arm. The experimental testing of these prototypes demonstrated reduced physical stress when compared to the unsupported environment. The support from below the elbow seemed to be the most practical in terms of implementation in various operation room settings and acceptance by surgeons. Step 4 and 5 are still in process.ConclusionsErgonomic problems have been identified in LS that could be addressed by an ASsyst. The concept of supporting the elbow from below has been found to be the most promising approach.

Backing up a trailer can be a challenge, particularly for inexperienced recreational drivers. We therefore develop two feedback controllers, which support the driver with automatic steering inputs in various situations. Based on the kinematics of the general one-trailer system, we first derive an input/output-linearizing control law that asymptotically stabilizes a given curvature for the trailer. This enables the driver to directly steer the trailer, e.g., by means of a turning knob, such that the trailer will automatically be prevented from jackknifing. The control task is then modified and solved so that the vehicle can also take over the complete stabilization task along given paths. In combination with a path-planning algorithm, this enables automated parallel parking for example. The complete system is implemented on a rapid-prototyping environment and evaluated in real-world scenarios.

My paper contained much censure. I wish, therefore, to say that the work of the Council on Pharmacy and Chemistry, which is publishing its deliberations weekly in The Journal, is one of the best means that has been put forward thus far in order to cure the evils I have mentioned. One man may lead a horse to water, but 20,000 can not make him drink. If pharmacopeias are revised every five or ten years, or oftener, the very people who should read them will not. What can we do with them? The American Medical Association can wield a great influence; there are 32,000 members now, I am told. They will finally overcome these miserable trade journals, some of which since they became rich have become good. Let's keep up a constant warfare. It means a campaign of education, and I trust we shall keep at it until the body politic of medicine, which is now like an evil sore, is cleansed.

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