CAFD: Context-Aware Fault Diagnostic Scheme towards Sensor Faults Utilizing Machine Learning.

Sensors' existence as a key component of Cyber-Physical Systems makes it susceptible to failures due to complex environments, low-quality production, and aging. When defective, sensors either stop communicating or convey incorrect information. These unsteady situations threaten the safety, economy, and reliability of a system. The objective of this study is to construct a lightweight machine learning-based fault detection and diagnostic system within the limited energy resources, memory, and computation of a Wireless Sensor Network (WSN). In this paper, a Context-Aware Fault Diagnostic (CAFD) scheme is proposed based on an ensemble learning algorithm called Extra-Trees. To evaluate the performance of the proposed scheme, a realistic WSN scenario composed of humidity and temperature sensor observations is replicated with extreme low-intensity faults. Six commonly occurring types of sensor fault are considered: drift, hard-over/bias, spike, erratic/precision degradation, stuck, and data-loss. The proposed CAFD scheme reveals the ability to accurately detect and diagnose low-intensity sensor faults in a timely manner. Moreover, the efficiency of the Extra-Trees algorithm in terms of diagnostic accuracy, F1-score, ROC-AUC, and training time is demonstrated by comparison with cutting-edge machine learning algorithms: a Support Vector Machine and a Neural Network.

Examination of geographical, clinical and intrahost variations in the 3' repeat region of cagA gene in Helicobacter pylori.

The size variation of the cytoxin-associated protein (cagA), which is dependent on the 3' repeat region (3'RR) of the cagA gene, is known to play a crucial role in the pathogenesis of Helicobacter pylori infection. The present study evaluated the relationship between the 3'RR variation and the geographic distribution, clinical manifestations, and locations of colonization in the stomach. We evaluated the 3'RR of H. pylori isolates from 78 patients with gastric cancer, peptic ulcer, and non-ulcer dyspepsia from Japan, Hong Kong, India, and the United States and assessed the variations of 3'RR according to the geographical and clinical characteristics. Sixty eight (87.2%) patients had the same 650 bp band without geographical differences. The frequency of polymorphisms in the 3'RR did not differ when compared to the clinical manifestations (P=0.868). The length of 3'RR did not differ by location of colonization. In conclusion, the 3'RR variation of cagA gene is not associated with the geographical and clinical characteristics of the patients studied.

Solid-pseudopapillary tumor of the pancreas.

BACKGROUND: Solid-pseudopapillary tumor (SPT) of the pancreas is a low-grade malignancy, which has been infrequently observed in adolescent and young adult females since first report by Frantz in 1959. In this article, we describe our experience of 8 cases of SPT with the clinical features, diagnosis, treatments, and outcomes. METHODS: We retrospectively reviewed the medical records and images of 8 patients who underwent surgery for SPT between January 1995 and December 2004. RESULTS: Seven females and 1 male with the mean age of 29 years (range, 10 to 64) at presentation were identified. Three patients presented palpable abdominal mass, 2 with abdominal pain, and the remainder with no specific symptom. The mean diameter of the tumors was 7.9 cm (range, 4.0 to 10.0). Four were located in the tail, 3 in the body, and 1 in the head. Surgical procedure included distal pancreatectomy with/without splenectomy in 7 patients and Whipple operation in 1 with no surgical morbidity and mortality. All were alive without evidence of recurrence after mean follow-up of 26.4 months (range, 1 to 66). CONCLUSIONS: SPT of the pancreas is an unusual neoplasm and typically occurs in young females presenting well-demarcated pancreatic masses, which are amenable to cure by complete surgical resection.

A case of primary pancreatic non-Hodgkin's lymphoma.

Primary pancreatic lymphoma is rare, comprising 0.2-4.9% of all pancreatic malignancies and less than 1% of cases of non-Hodgkin's lymphoma. Many patients are diagnosed with lymphoma after radical resection. We report a rare presentation of diffuse large B cell lymphoma, appearing as a primary tumor of the pancreas. A 61-year old female was admitted to the hospital with the complaint of right upper abdominal pain. Computed tomography of the abdomen showed a well defined mass located at the head of the pancreas. A frozen section of pancreas, during laparotomy, revealed lymphoma. The patient received 6 cycles of chemotherapy and is currently in complete remission. This case underscores the importance of differentiating primary lymphoma from the more common adenocarcinoma of the pancreas as treatment and prognosis differ significantly. Primary pancreatic lymphoma should be considered in the differential diagnosis of pancreatic tumors and an attempt to obtain a tissue diagnosis is always necessary before proceeding to radical surgery, especially on young patients.

[The factors related to the prognosis of solitary hepatocellular carcinoma after radiofrequency ablation].

BACKGROUND/AIMS: Several risk factors, such as size and location, are related to local recurrence after radiofrequency ablation (RFA) in the treatment of hepatocellular carcinoma (HCC). The objectives of this study were to clarify factors related to prognosis. METHODS: From October 1999 to December 2002, we performed RFA for 107 consecutive patients with solitary HCC. We evaluated spiral computed tomography and serum alpha-fetoprotein level every 3 months after RFA. Seven possible factors for prognosis were analyzed using the Cox proportional hazards regression model: tumor size, tumor location, age, sex, etiology, platelet count, and Child-Pugh classification. Overall survival and disease free survival rate were estimated using the Kaplan-Meier method, and differences between two groups were compared using the log rank test. RESULTS: The Kaplan-Meier estimates of overall survival after radiofrequency ablation were 90.5% at 12 months, 67.4% at 24 months and 46.4% at 36 months and disease free survival were 71.4%, 46.7% and 20.9%, respectively. Using the Cox proportional hazards regression model, it was shown that with regard to overall survival and disease free survival, Child-Pugh classification (P=0.001, P=0.026) and platelet count (P<0.001, P=0.002) were statistically significant factors. The other factors did not have a statistically significant relationship to overall survival and disease free survival. CONCLUSIONS: The size and location known as local recurrence factors were not statistically significant with regard to survival and disease free survival. The Child-Pugh classification and platelet count, that reflect the liver function at the time of RFA, were significant factors for prognosis.

Clear cell hepatocellular carcinoma with spontaneous regression of primary and metastatic lesions.

The prognosis of advanced hepatocellular carcinoma (HCC) tends to be poor. Spontaneous regression of this lesion is extremely rare. In this report, we describe a case of HCC which spontaneously regressed along with a metastatic lesion of the chest wall. A huge HCC in the right lobe, the largest diameter of which was about 15 x 12 cm, developed in a 72-year-old man. He and his family refused further treatment. Three months after the diagnosis, metastasis to the chest wall was detected. We prescribed a painkiller for him in order to alleviate chest pain. Fourteen months after the diagnosis, the tumor size of the primary lesion was downsized to 3 x 4 cm in diameter. A biopsy taken from the chest wall proved to be clear cell HCC (CHCC). Since then, the metastatic lesion has also disappeared. Here, we report this unusual histologically proven CHCC with literature reviews.