Identifying Implementation Bugs in Machine Learning based Image Classifiers using Metamorphic Testing

We have recently witnessed tremendous success of Machine Learning (ML) in practical applications. Computer vision, speech recognition and language translation have all seen a near human level performance. We expect, in the near future, most business applications will have some form of ML. However, testing such applications is extremely challenging and would be very expensive if we follow today's methodologies. In this work, we present an articulation of the challenges in testing ML based applications. We then present our solution approach, based on the concept of Metamorphic Testing, which aims to identify implementation bugs in ML based image classifiers. We have developed metamorphic relations for an application based on Support Vector Machine and a Deep Learning based application. Empirical validation showed that our approach was able to catch 71% of the implementation bugs in the ML applications.Comment: Published at 27th ACM SIGSOFT International Symposium on Software Testing and Analysis (ISSTA 2018

A Cross-Sectional Study of prevalence of Prostate lesions and inter-Observer Variability in Histopathological Reporting

Introduction: To report the prevalence of various prostate lesions in the general population through cadaver prostates and to determine the interobserver variability for reporting high-grade lesions of the prostate. Materials and Methods: The cross-sectional study was carried out on 110 autopsy specimens of healthy prostate with deceased age over 40 years. The specimens were grossed, sectioned, stained and reported independently by the primary investigator resident and the senior professor. The lesions were categorized into prostatitis, benign prostate hypertrophy (BPH), prostate intraepithelial neoplasia (PIN) further graded as low grade (LGPIN) and high grade (HGPIN) and prostate cancer (PCa). Inter-rater kappa agreement was used to find the strength of agreement between the pathologists. Results: Among 110 prostate specimens, only 8(7.27%) cases had normal prostate with 72 (65.4%) having BPH and 12(10.9%) cases having prostatitis. There were 17 cases of PIN with 11 cases of HGPIN and 6 cases of LGPIN. Malignancy was seen in only a single case (95% Confidence Interval: 0% - 2.71%). The primary resident missed 4 cases of HGPIN and 2 cases of LGPIN. Interobserver agreement between the resident and senior pathologist was fair (Kappa 0.282, p value=0.335). Conclusion: In conclusion, prostate lesions remain latent and show high prevalence in general population without causing any symptoms. The study depicts a high interobserver variability of reporting the high-grade lesions of prostate since they cause a diagnostic dilemma with PCa. The consultation with uropathologists and use of molecular markers must be included in the diagnostic panel while reaching a final diagnosis. &nbsp

Concurrent chemoradiation in head and neck cancers with weekly cisplatin: analysing toxicities

Background: Head and neck cancers constitute 6% of cancers worldwide. The management requires a multidisciplinary approach. Concomitant chemoradiotherapy with cisplatin is the standard approach for locally advanced head and neck cancers. The most commonly used regime uses three weekly cisplatin which is more toxic. Low-dose once-a-week cisplatin is substituted because of perceived lower toxicity and convenience.  Methods: Squamous cell carcinoma of stage III, IVA and IVB of oropharynx, hypopharynx and larynx were studied for one year. 82 patients were studied. Total dose of radiation was 66Gy/33#/6 ½ weeks from Monday to Friday with inj. Cisplatin 40mg/m2 i.v. infusion weekly.Results: 88% of patients were able to complete five or more weekly chemotherapy cycles with cumulative dose of 200mg/m2. Grade 2 and 3 acute toxicities were seen in weekly cisplatin arm but were conservatively managed.Conclusions: Weekly cisplatin can be used with concurrent radiotherapy as the acute toxicities are manageable and is well tolerated

An artificial intelligence based automation solution for optimal scheduling of ELISA assays

The thesis focuses on designing a hardware solution and building an optimal scheduling solution for automating ELISA assays used in clinical diagnostics. The hardware solution consists of a cylindrical robot running on a rail which integrates stand-alone instruments. The scheduling algorithm provides software solution which provides a framework of automation. Assays running on such an automated platform have unique requirements which differentiate their scheduling from ordinary job shop scheduling problems. The first difference is that an assay cannot wait at any stage once it has entered the system. Thus waiting time has to be zero. This is a rigid requirement, not found in job shop scheduling. The second difference is that a resource/machine can be used again and again after first processing has finished. This means an assay can return to the same machine after undergoing some operations at other machines. These two requirements and different needs of different assays make this problem fairly complicated. Two scheduling algorithms are developed–Earliest Fit and Exhaustive Enumeration. The former is used in industry and is non-optimal, while the latter yields optimal solution. Exhaustive Enumeration is a procedure in which all possible schedules are formed. This is followed by discarding duplicate schedule by using the technique of pattern recognition. Finally, the schedule, which is optimal, is selectedMechanical Engineerin

Hormone refractory carcinoma prostate with peritoneal metastases and malignant ascites without skeletal involvement: A case report and review of literature

Peritoneal carcinomatosis is rare in prostate cancer especially in the absence of skeletal or other visceral metastases. We report a case of hormone refractory adenocarcinoma prostate presenting with only peritoneal metastases and massive malignant ascites. Palliation with docetaxel based cytotoxic chemotherapy resulted in clinical improvement of refractory ascites decreasing respiratory embarrassment and thereby improving the quality of life

Stacked Si2BN monolayers as ultra-high-capacity anode material for divalent Mg-ion batteries

In pursuit of developing next-generation energy storage systems, there has been increasing effort in multivalent rechargeable batteries, such as magnesium-ion batteries (MgIBs). Non-toxicity, earth abundance, and high storage capacity due to their divalent nature make MgIBs an ideal alternative to the existing lithium-ion batteries (LIBs). However, exploring efficient electrode materials capable of storing large quantities of Mg ions is one of the biggest challenges in actualizing MgIBs. Here first-principles density functional theory (DFT) simulations are employed to explore the potential of Si2BN monolayers as a novel anode material for MgIBs. We find that under the maximum coverage effect, the stackedSi2BN could attain a specific capacity of 359.94 mAh g−1, which further enhances to 1418.45 mAh g−1 with a defect concentration of 12 %. The open-circuit voltages fall in the ranges of 0.42–0.46 V and 0.88–0.98 V for the pristine and defected Si2BN, respectively. Diffusion barrier calculations reveal that Mg ions diffuse 125 times faster on pristine Si2BN than the defected one. Our simulations determine that the electronic structures, binding mechanism, equilibrium cell voltages, ionic mobilities, and thermal stabilities of stacked Si2BN make it an excellent anode material for MgIBs

A rare case of dystrophinopathy: Duchenne muscular dystrophy–Becker muscular dystrophy intermediate complex

An 18-year-old boy with no significant perinatal history presented with insidious onset of slowly progressive flaccid paraparesis with muscle wasting in thighs. On examination, the patient had flaccid motor quadriparesis and partial atrophy of proximal thigh muscles. This was accompanied by pseudohypertrophy of calf muscles and extensor muscles in the dorsum of foot. Investigations revealed very high levels of creatinine phosphokinase in the patient (6495 IU/l in contrast to normal range of 55–170 IU/l) and in his sister (718 IU/l). Echocardiography showed dilated cardiomyopathy with severe left ventricular dysfunction. The multiplex ligation-dependent probe amplification revealed deletion of exons 3 to 7 in the short arm of X chromosome (Xp21). Based on the clinical features and investigation reports, a diagnosis of intermediate phenotype of Duchenne and Becker muscular dystrophy was made