Automatic Verification of Message-Based Device Drivers

We develop a practical solution to the problem of automatic verification of the interface between device drivers and the OS. Our solution relies on a combination of improved driver architecture and verification tools. It supports drivers written in C and can be implemented in any existing OS, which sets it apart from previous proposals for verification-friendly drivers. Our Linux-based evaluation shows that this methodology amplifies the power of existing verification tools in detecting driver bugs, making it possible to verify properties beyond the reach of traditional techniques.Comment: In Proceedings SSV 2012, arXiv:1211.587

Testing Two Student Nurse Stress Instruments in Chinese Nursing Students:A Comparative Study Using Exploratory Factor Analysis

Background. The development and transformation of nursing within professional tertiary education have exerted a great pressure and challenge upon nursing students. Stress experienced by nursing students is a common precursor of psychological distress and attrition. However, no scale is specifically used to evaluate the sources of stress experienced by nursing students in Mainland China. Aims and Objective. This study is aimed at testing and comparing the reliability and validity including sensitivity and specificity of two nursing students’ stress instruments, the Chinese version of Student Nurse Stress Index Scale (SNSI-CHI), and the Stressors in Student Nursing Scale (SINS-CN) in Chinese nursing students, and describing the stress status of nursing students in China. Methods. A cross-sectional survey was conducted in two nursing schools in Henan Province from August 2017 to January 2018. Data were collected by using a questionnaire comprising the Chinese version of SNSI (SNSI-CHI), the Chinese version of SINS (SINS-CN), and the Chinese Perceived Stress Scale (CPSS). Homogeneity and stability, content, construct and concurrent validity, and sensitivity and specificity were assessed. Results. The Cronbach’s alpha (α) of SNSI-CHI was 0.90, and the item-to-total correlations ranged from 0.35 to 0.66. The Cronbach’s α of SINS-CN was 0.93, and the item-to-total correlations ranged from 0.19 to 0.61. The findings of exploratory factor analysis (EFA) confirmed a good construct validity of SNSI-CHI and SINS-CN. The Pearson’s rank correlation coefficients, between total scores of SNSI-CHI and CPSS and SINS-CN and CPSS, were assessed to 0.38 (P<0.01) and 0.39 (P<0.01), respectively. Regarding the CPSS, as the criterion, the cut-points of SNSI-CHI and SINS-CN for the area under the receiver operator characteristic (ROC) curve were 0.77and 0.66, respectively. Conclusion. Both scales are valid and reliable for evaluating the source of stress of student nurses in China. Each has its own characteristics, but the SNSI-CHI demonstrated marginal advantage over the SINS-CN. The SNSI-CHI is short, is easily understood, and with clear dimension for the nursing students, and the SNSI-CHI is more acceptable for the users in China

Giant Merkel cell carcinoma of the eyelid: a case report and review of the literature

Merkel cell carcinoma (MCC) is a rare cutaneous tumor and cases located in the eyelid have been described, but still its rarity may lead to difficulty in diagnosis and delay in treatment. A 51-year-old female patient that presented with large lesions in the eyelid underwent surgery after the diagnosis of acute chalazion. Following respiratory distress secondary to pulmonary metastasis, the patient's condition deteriorated and was not fit for complete excision treatment. Histopathological investigation of the biopsies, taken from the tumor, revealed that it was undifferentiated small cell carcinoma. Our aim with this paper is to point out that more cases should be reported for more effective diagnosis, histopathological study, clinical investigation, treatment and prognosis of this specific neoplasm

Clinical outcome observation of the embolization of orbital vascular malformation with medical glue under direct intra-operative view

Abstract Background Orbital vascular malformation often encircles normal tissue with ill-defined borders. It is easy to bleed during resection operation, making surgical treatment difficult and lesions hard to be removed completely. In this study we aimed to summarize the treatment outcomes by embolizing orbital vascular malformation with intraoperative intracavitary injection of medical glue . Methods A retrospective observational and cross-sectional case series study enrolled 31 patients (male = 9, female = 22) with orbital vascular malformations, who were treated from March 2008 to September 2017 at our institution. The clinical features, operation records, pathological reports and follow-up data were analyzed. Results The location of vascular malformations involved intraorbital (14 cases), superficial area of eyelid and/or face (7 cases), both intraorbital and superficial area (10 cases). Imaging examination showed a solitary mass with regular shape in 8 cases and a space occupying lesion with irregular shape and ill-defined margins in 23 cases. There were 9 cases had optic nerve involved. Surgical debulkling were performed via skin incision on the mass surface (5 cases), lateral orbitotomy (2 cases), and anterior orbitotomy (24 cases). During the operation, lesions were partly exposed and injected with medical glue. The amount of injected glue was 0.25 ml to 2.5 ml in divided doses. The lesions and remnant glue were removed after the glue had turned hard. The whole procedure caused less bleeding and was easier performing than usual. Topical skin aseptic inflammation took place on the same side of the superficial eyelid lesions in 3 cases. One patient suffered from sudden central retinal artery embolism on the third day post operation. With timely rescue and appropriate procedure, visual acuity recovered to 20/32. There were no recurrences in 29 cases. Conclusions Embolization of orbital vascular malformation with medical glue intraoperatively made it easy to control hemorrhage. Surgeons should be careful with glue application methods in order to avoid complications

The Fracture Behavior and Thermal Stability of Commercially Pure Nickel Sheets Processed by Constrained Groove Pressing

Constrained groove pressing (CGP) is one of the most promising severe plastic deformation (SPD) techniques suitable for producing ultra-fine grained (UFG) sheet or plane metallic materials with unique physical, chemical, and mechanical properties. However, the heavily deformed sheets are usually with high strength but low ductility due to work hardening and micro-cracking, and the UFG microstructure and high strength are unstable especially when exposed to high temperatures. Thus, in this work, CGP was conducted on commercially pure nickel sheets and, firstly, the fracture mechanism of the processed sheets was examined. Then, the annealing behavior of CGP nickel sheets was investigated in detail to explore their thermal stability and improve their ductility. The results showed that significant grain refinement and strength improvement of the nickel sheets were achieved with great loss of ductility. The fracture surface morphology of the sheet sample exhibited typical characteristics of fatigue fracture, and inhomogeneous strain distribution and work hardening determined the micro-crack initiation position and propagation direction. The CGP sheets by one and two passes showed high thermal stability up to 650 and 600 &deg;C, respectively, owing to different stored internal stresses and accumulated energy. In both cases, obvious recovery of elongation to failure from 12.7% and 10.6% to 29.3% and 27.3% were achieved by CGP with post-deformation annealing treatment, respectively, with acceptable drop of strength

Groove pressing and its research progress

In order to systematically study the application of groove pressing in preparing bulk mass ultra-fine grain sheet metal, the fundamental principles, plastic mechanics analysis and classification of groove pressing are introduced, and on the basis of which, the influence rules and mechanism of processing factors such as pass number, deformation temperature and die structure on groove pressing are reviewed, and some key problems such as thermal stability of processed materials, process improvements and deformation path, deformation homogeneity analysis and process optimization are summarized. The research trends of groove pressing in the fields of application to sheet metals difficult to deform at room temperature, improvement of ductility, toughness and formability of processed sheets as well as its plastic deformation mechanism are prospected: in the future, groove pressing will be used for sheet metals which have limited formability but wide industrial applications such as magnesium alloys and titanium alloys, and much attention should be paid to investigation on performance adjustment mechanism and methods for processed sheets and exploration of effective technological measures for preventing cracks; meanwhile, the evolution mechanism of microstructure and properties of groove pressed materials must be systematically and thoroughly revealed

Monitoring chip-branches failure of multichip IGBT module using change rate of gate voltage

In order to increase system reliability, it is an economical and efficient method to monitor the defective multichip insulated gate bipolar transistor (IGBT) modules, which are widely used in various high-power electronic systems. A method is presented to monitor chip-branches failure caused by bond-wires defects inside the multichip IGBT modules when the modules are in the off-state. It is based on that the gate input capacitance of the multichip IGBT module will be changed by the failure of chip branches caused by bond-wires defects. The change rate of gate voltage under the constant gate current can be used to characterize the failure. Firstly, according to the gate charge characteristics, the relationship between the change rate of gate voltage and the chip-branches failure under the constant gate current is given. The process of monitoring chip-branches failure is described. Then, a gate driver is presented, which contains a constant current source, and the feasibility of the monitoring method is verified. The study results show that under the constant current source driver and within the specific range of gate voltage, the change rate of gate voltage is independent of temperature and collector–emitter voltage, only related to the failure of chip branches due to bond-wires defects in the multichip IGBT module and increases significantly with the chip-branches failure. Finally, the characteristics of this method are analyzed by comparison with other similar condition monitoring methods. This method is easy to measure and can be applied to the case of real-time and online monitoring