Robot Localization in Tunnels: Combining Discrete Features in a Pose Graph Framework.

Robot localization inside tunnels is a challenging task due to the special conditions of these environments. The GPS-denied nature of these scenarios, coupled with the low visibility, slippery and irregular surfaces, and lack of distinguishable visual and structural features, make traditional robotics methods based on cameras, lasers, or wheel encoders unreliable. Fortunately, tunnels provide other types of valuable information that can be used for localization purposes. On the one hand, radio frequency signal propagation in these types of scenarios shows a predictable periodic structure (periodic fadings) under certain settings, and on the other hand, tunnels present structural characteristics (e.g., galleries, emergency shelters) that must comply with safety regulations. The solution presented in this paper consists of detecting both types of features to be introduced as discrete sources of information in an alternative graph-based localization approach. The results obtained from experiments conducted in a real tunnel demonstrate the validity and suitability of the proposed system for inspection applications.

Calcinosis cutis universalis in a patient with systemic lupus erythematosus.

Deposition of calcium salts in the skin and subcutaneous tissue occurs in a variety of rheumatic diseases, being most commonly associated with scleroderma, CREST (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia), dermatomyositis, and overlap syndromes but is a rare complication of systemic lupus erythematosus (SLE). Calcinosis is classified into four subsets: dystrophic, metastatic, idiopathic, or calciphylaxis/iatrogenic. The pathophysiology of calcinosis cutis remains unclear. Our patient developed extensive areas of calcifications in the trunk and extremities (calcinosis universalis) 8 years after SLE diagnosis, which would correspond to a form of dystrophic calcification. No response was observed after treatment with oral diltiazem for 3 months. We review the literature on the pathogenesis and prevalence of calcinosis universalis in SLE.