199 research outputs found

    Secure and dependable cyber-physical system architectures

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    The increased computational power and connectivity in modern Cyber-Physical Systems (CPS) inevitably introduce more security vulnerabilities. The concern about CPS security is growing especially because a successful attack on safety-critical CPS (e.g., avionics, automobile, smart grid, etc.) can result in the safety of such systems being compromised, leading to disastrous effects, from loss of human life to damages to the environment as well as critical infrastructure. CPS poses unique security challenges due to its stringent design and implementation requirements. This dissertation explores the structural differences of CPS compared to the general-purpose systems and utilizes the intrinsic characteristics of CPS as an asymmetric advantage to thwart and detect security attacks to safety-critical CPS. The dissertation presents analytic techniques and system design principles to enhance the security and dependability of CPS, with particular focus on (a) modeling and reasoning about the logical and physical behaviors of CPS and (b) architectural and operating-system supports for trusted, efficient run-time monitoring as well as attack-resiliency

    The Clinical Usefulness of 18F-FDG PET/CT for the Evaluation of Lymph Node Metastasis in Periorbital Malignancies

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    PURPOSE: Surgical treatment of malignancies in the oral cavity and subsequent radiotherapy often result in an oral condition unfavorable for prosthodontic rehabilitation. This study assessed the quality of life related to oral function in edentulous head and neck cancer patients following oncology treatment of malignancies in the lower region of the oral cavity. MATERIALS AND METHODS: Patients treated between 1990 and 2000 with surgery and radiotherapy for a squamous cell carcinoma in the oral cavity who were edentulous in the mandible and had been treated with a conventional, non-implant-retained denture received an invitation for a clinical check-up (clinical assessment, questionnaires regarding oral function and quality of life). RESULTS: Sixty-seven of the 84 patients who fulfilled the inclusion criteria were willing to participate in the study. The mean irradiation dosage that these patients had received in the oral region was 61.8 +/- 5.4 Gy. Half of the patients (n=33) were not very satisfied with their prostheses; they wore their mandibular prostheses at most a few hours per day. It was concluded from the clinical assessment that two thirds of the patients (n 4) could benefit from an implant-retained mandibular denture. Analyses of the questionnaires revealed no significant associations between functional assessments, quality of life, and parameters such as size of the primary tumor, location of the primary tumor, and different treatment regimes. Despite cancer treatment, the patients reported a rather good general quality of life. CONCLUSIONS: Sequelae resulting from radiotherapy probably dominate oral function and quality of life after oncology treatment. In two thirds of the patients, improvement of oral function and related quality of life would be expected with the use of an implant-retained mandibular denture

    Initial Biopsy Outcome Prediction in Korean Patients-Comparison of a Noble Web-based Korean Prostate Cancer Risk Calculator versus Prostate-specific Antigen Testing

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    We developed and validated a novel Korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy in a Korean population. Data were collected from 602 Koreans who underwent initial prostate biopsies due to an increased level of prostate-specific antigen (PSA), a palpable nodule upon digital rectal examination (DRE), or a hypoechoic lesion upon transrectal ultrasound (TRUS). The clinical and laboratory variables were analyzed by simple and multiple logistic regression analysis. The area under the receiver operating characteristic curve (AUC) was computed to compare its performance to PSA testing alone. Prostate cancer was detected in 172 (28.6%) men. Independent predictors included age, DRE findings, PSA level, and prostate transitional zone volume. We developed the KPCRC using these variables. The AUC for the selected model was 0.91, and that of PSA testing alone was 0.83 (P < 0.001). The AUC for the selected model with an additional dataset was 0.79, and that of PSA testing alone was 0.73 (P = 0.004). The calculator is available on the website: http://pcrc.korea.ac.kr. The KPCRC improved the performance of PSA testing alone in predicting the risk of prostate cancer in a Korean population. This calculator would be a practical tool for physicians and patients
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