Conditional Value-at-Risk for Reachability and Mean Payoff in Markov Decision Processes

We present the conditional value-at-risk (CVaR) in the context of Markov chains and Markov decision processes with reachability and mean-payoff objectives. CVaR quantifies risk by means of the expectation of the worst p-quantile. As such it can be used to design risk-averse systems. We consider not only CVaR constraints, but also introduce their conjunction with expectation constraints and quantile constraints (value-at-risk, VaR). We derive lower and upper bounds on the computational complexity of the respective decision problems and characterize the structure of the strategies in terms of memory and randomization

Orthodontic repositioning of traumatically intruded permanent incisors - A report of three cases

Intrusive luxation of permanent teeth is one of the most serious traumatic dental injuries involving damage to the gingival tissue, periodontal ligament, cementum, bone and to the neurovascular supply of the pulp. In addition to disruption of normal tooth development and eruption, it can also lead to pulpal necrosis, root resorption and marginal bone loss. Based on the extent/severity, intrusion maybe classified into mild (<3 mm), moderate (3-6mm) and severe (>6mm). Available techniques for managing intrusive luxation include a wait-and-watch approach to allow for spontaneous re-eruption, orthodontic traction and surgical repositioning. The type of treatment approach employed depends upon the stage of root development, severity of intrusive luxation and the presence or absence of alveolar fractures. It is difficult to predict reliable outcomes with these approaches, since the presence of variables such as the severity of intrusion, associated crown/root fracture, stage of root development and presence of alveolar fractures may alter the prognosis. The present article presents a series of three cases with intrusive luxation of permanent incisors successfully treated using an interdisciplinary approach involving orthodontic traction along with endodontic rehabilitation

An Interesting Case of Sebaceous Gland Carcinoma of Upper Eyelid with Tubercular Lymphadenitis

Sebaceous gland carcinoma (SGC) is a rare, potentially aggressive tumor and the third most common malignancy of the eyelid.We present a case of SGC (confirmed by histopathology) of right upper eyelid in a 48-year-old female, which was managed by excision of mass with 5 mm clear margin with lid reconstruction using Cutler Beard technique and three cycles of cryotherapy. A positive uptake on PET scan of left cervical lymph node followed by FNAC of the same showed tubercular lymphadenitis rather than metastasis. Coming across this case raises a possibility of association of SGC with TB but having said that further research is needed for the same

dtControl: Decision Tree Learning Algorithms for Controller Representation

Decision tree learning is a popular classification technique most commonly used in machine learning applications. Recent work has shown that decision trees can be used to represent provably-correct controllers concisely. Compared to representations using lookup tables or binary decision diagrams, decision trees are smaller and more explainable. We present dtControl, an easily extensible tool for representing memoryless controllers as decision trees. We give a comprehensive evaluation of various decision tree learning algorithms applied to 10 case studies arising out of correct-by-construction controller synthesis. These algorithms include two new techniques, one for using arbitrary linear binary classifiers in the decision tree learning, and one novel approach for determinizing controllers during the decision tree construction. In particular the latter turns out to be extremely efficient, yielding decision trees with a single-digit number of decision nodes on 5 of the case studies