Geometry of Policy Improvement

We investigate the geometry of optimal memoryless time independent decision making in relation to the amount of information that the acting agent has about the state of the system. We show that the expected long term reward, discounted or per time step, is maximized by policies that randomize among at most $k$ actions whenever at most $k$ world states are consistent with the agent's observation. Moreover, we show that the expected reward per time step can be studied in terms of the expected discounted reward. Our main tool is a geometric version of the policy improvement lemma, which identifies a polyhedral cone of policy changes in which the state value function increases for all states.Comment: 8 page

A Risk Comparison of Ordinary Least Squares vs Ridge Regression

We compare the risk of ridge regression to a simple variant of ordinary least squares, in which one simply projects the data onto a finite dimensional subspace (as specified by a Principal Component Analysis) and then performs an ordinary (un-regularized) least squares regression in this subspace. This note shows that the risk of this ordinary least squares method is within a constant factor (namely 4) of the risk of ridge regression.Comment: Appearing in JMLR 14, June 201

“Implementation on Distorted Fingerprints”

Flexible distortion of fingerprints is the main origin of false non-match. While this origin disturbs all fingerprint recognition applications, it is mainly risk in negative recognition applications, such as watch list duplication applications. In such things, malignant user mayconsciously distort their fingerprints to hide his originality or identification. This paper, suggested novel algorithms to identify and modify skin distortion based on a single fingerprint image. Distortion detection is displayed as a two-class categorization problem, for which the registered ridge orientation map and period map of a fingerprint are beneficial as the feature vector and a SVM classifier is trained to act the classification task. Distortion rectification (or equivalently distortion field estimation) is viewed as a regression complication, where provide the input as a distorted fingerprint and generate the output as distortion field. To clarify this Problem, offline and online stages are important. A database (called reference database) of various distorted reference fingerprints and corresponding distortion fields is built in the offline stage, and then in the online stage, the closest neighbor of the input fingerprint is organized in the reference database and the corresponding distortion field is used to transform (Convert) the input distorted fingerprint into a normal undistorted fingerprints

Efficacy of intravenous hydration drip versus amino acid drip in idiopathic oligohydramnios

Background: Role of intravenous hydration and amino acid infusion is well documented for the treatment of foetal growth restriction and associated oligohydramnios. The present study concentrates on the efficacy of intravenous hydration and amino acid infusions in cases of isolated oligohydramnios.Methods: 30 antenatal mothers having isolated oligohydramnios and fulfilling the inclusion criteria were selected for the study. They were randomized and administered 6 drips of normal saline or amino acid infusions. The AFI was assessed before and after the infusions. The rise in AFI, need of repeat infusions and foetal outcome was studied and analyzed.Results: The results were tabulated with respect to age of patients, gestational age, gravida status, AFI on admission and post infusions, comparison between the two groups after the 6 drips, need of repeat infusions and the maternal and perinatal outcome. Analysis of the data was performed using Chi-Square test.Conclusions: This study points towards the use of intravenous amino acids and normal saline in increasing the liquor in idiopathic oligohydramnios and proves useful in reducing perinatal morbidity and mortality and thus improving pregnancy outcomes, prolonging gestational age at time of delivery thereby improvement in weight gain. However the difference between the study groups was statistically not significant

A rare case of ovarian thecoma in a postmenopausal woman

Thecomas are very rare solid tumors of ovary and are a type of sex-cord stromal tumors. They account for approximately 0.5%-1% of primary ovarian tumors. We report a rare incidence of this tumor which presented in a postmenopausal woman. She presented with abdominal discomfort and underwent an ultrasonography revealing a solid ovarian tumor. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy. Histopathological examination showed benign thecoma. Hence it is important to keep this benign condition in mind when dealing with solid ovarian tumors in postmenopausal woman

The comparison of the efficacy of intra-peritoneal instillation along with local infiltration with bupivacaine versus placebo for post-operative analgesia after laparoscopic tubal ligation

Background: Intra-peritoneal instillation of local anesthetics has been shown to minimize post-operative pain after laparoscopic surgeries. The present study was undertaken with the following aim to compare the efficacy of intra-peritoneal instillation and local infiltration with bupivacaine versus placebo for post-operative analgesia after laparoscopic tubal ligation. To correlate the advantages and side effects of the drugs during the procedure. To establish a protocol for the use of bupivacaine instillation and infiltration for post-operative analgesia after laparoscopic tubal ligation.Methods: A prospective study was carried out in a tertiary care hospital attached to a teaching medical institute. Institutional ethics committee approval was obtained for this randomized control study (double blind) including 50 women who will be divided in two groups. Group A will be administered intra-peritoneal bupivacaine along with local infiltration. Group B will be administered normal saline. Post-operative pain will be monitored by a blind observer and rescue analgesia will be administered at visual analogue score of 3.Results: Both the groups were comparable with respect to age and BMI. The mean duration of analgesia in Group A with bupivacaine was 315.60±79.9 min (Median 300 min).  The mean duration of analgesia in Group B with normal saline was 138.20±46.97 min (Median 150 min, p value <0.001).Conclusions: The study depicts a significant pain relief after use of bupivacaine. Bupivacaine instillation in the peritoneal cavity along with local infiltration of the drug gives prolongs pain relief as compared to normal saline

Synergistic Hypergolic Ignition of Amino End Group in Monomers and Polymers

A few monomers, oligomers and polymers with amino end groups have been discovered to undergo synergistic ignition with red fuming nitric acid (RFNA) when mixed with large quantities of magnesium powder. Aluminium powder under similar conditions does not ignite the mixture while powders of Zn, Co and Cu cause the ignition. Amongst the polymers used in the experiment commercially available nylon 6 is the most important which may be used as a binder for rocket propellant fuel grains, hypergolic with RFNA. Degree of polymerisation or the chain length of the polymers does not drastically affect the synergistic ignition of the polymer mixture with magnesium powder but high molecular weight and fully aromatised polymers like Kevlar and Nomex fail to ignite under similar conditions. Based upon the earlier work of the authors, explanations for the phenomena oberved have been provided in terms of creation of hot spots leading to ignition at the amino end groups

Effect of fillers and fire retardant compounds on hydroxy terminated polybutadiene based insulators

A series of polyurethane compositions have been formulated using hydroxy-terminated polybutadiene as polymeric binder and carbon black as a major filler. Various binder-to-filler ratios of the formulations were evaluated to get calendered sheets. The formulations have been characterised for pot-life and rollability and the calendered sheets for mechanical and thermal properties, bUm rate, glass transition temperature, shore hardness and density . The different fillers tried were varieties of carbon black as a major filler; metal oxides, silicates and organic compounds; and fire retardants, such as zinc borate, sodium metaborate, ammonium dihydrogen phosphate and antimony trioxide. The structure and morphology of the fillers have been correlated with the properties. The optimised composition has been evaluated in an end-burning motor, as an insulator for case-bonded application, using a typical composite propellant. The results of interface bonding between the propellant and the insulator have also been presented