178 research outputs found
Laboratory Characterization of Geomechanical and Hydraulic Properties of Deep-Sea Hydrate Deposits
Methane hydrate has been considered as a future energy resource due to the vast amount of carbon in the natural hydrate reservoirs. During gas production from deep-sea hydrate deposits via depressurization, the effective stress of hydrate-bearing sediments can increase and alter the mechanical, physical, and hydraulic properties of the sediments. This thesis explores the geomechanical and hydraulic properties of tetrahydrofuran hydrate-bearing sand specimens subjected to high effective stress. Specifically, the focus is placed on understanding the role of hydrate crystals on the compressibility, particle grain crushing, wave velocity, the coefficient of earth pressure at rest, and permeability anisotropy in hydrate-bearing sediments. This thesis also explores hydrate morphology in clayey sediments and ensued geophysical properties using X-ray computed tomography and elastic wave measurements. The major findings of this thesis include: (i) the presence of hydrate crystals restrains particle rotation and rearrangement during loading, resulting in less pronounced particle crushing in sediments with higher hydrate saturation; (ii) the coefficient of earth pressure at rest K0 is mainly affected by hydrate saturation and applied vertical stress levels, and the cementation effect and the creep behavior of hydrate crystals play a vital roles in the evolution of K0; (iii) the permeability anisotropy of hydrate-bearing sediments increases exponentially with the increase of effective vertical stress under the oedometer condition, implying that vertical direction permeameter tests may underestimate the reservoir’s flow performance; and (iv) the morphology and hydrate saturation of tetrahydrofuran hydrate in clayey sediments are affected by the nucleation induction time, and the sediments with higher hydrate saturation attenuate P- and S-waves more significantly. These findings are expected to provide a comprehensive understanding of the geotechnical and the hydraulic behavior of hydrate-bearing specimens under high effective stress conditions and wave-based characterization of hydrate-bearing clayey specimens.Ph.D
Stability Metrics for Enhancing the Evaluation of Outcome-Based Business Process Predictive Monitoring
Outcome-based predictive process monitoring deals with predicting the outcomes of running cases in a business process using feature vectors extracted from completed traces in an event log. Traditionally, in outcome-based predictive monitoring, a different model is developed using a bucket containing different types of feature vectors. This allows us to extend the traditional evaluation of the quality of process outcome predictions models beyond simply measuring the overall performance, developing a quality assessment framework based on three metrics: one considering the overall performance on all feature vectors, one considering the different levels of performance achieved on feature vectors belonging to individual buckets, i.e., the stability of the performance across buckets, and one considering the stability of the individual predictions obtained, accounting for how close the predicted probabilities are to the cutoff thresholds used to determine the predicted labels. The proposed metrics allow to evaluate, given a set of alternative designs, i.e., combinations of classifier and bucketing method, the quality of the predictions of each alternative. For this evaluation, we suggest using either the concept of Pareto-optimality or a scenario-based scoring method. We discuss an evaluation of the proposed framework conducted with real-life event logs
Visualizing Quaternion Multiplication
Quaternion rotation is a powerful tool for rotating vectors in 3-D; as a result, it has been used in various engineering fields, such as navigations, robotics, and computer graphics. However, understanding it geometrically remains challenging, because it requires visualizing 4-D spaces, which makes exploiting its physical meaning intractable. In this paper, we provide a new geometric interpretation of quaternion multiplication using a movable 3-D space model, which is useful for describing quaternion algebra in a visual way. By interpreting the axis for the scalar part of quaternion as a 1-D translation axis of 3-D vector space, we visualize quaternion multiplication and describe it as a combined effect of translation, scaling, and rotation of a 3-D vector space. We then present how quaternion rotation formulas and the derivative of quaternions can be formulated and described under the proposed approach.112sciescopu
Radical prostatectomy versus radiotherapy as local therapy for primary tumors in patients with oligometastatic prostate cancer
IntroductionWe compared radical prostatectomy (RP) and radiotherapy (RT) as local therapies for primary tumors and examined their associations with survival outcomes and urinary tract complications in patients with oligometastatic prostate cancer (omPC).MethodsWe evaluated the data of 85 patients diagnosed with omPC who underwent local therapy for primary tumors between January 2008 and December 2018. Of the 85 patients, 31 underwent prostate RT, while 54 underwent RP. Oligometastatic disease was defined as the presence of fewer than five metastatic lesions without visceral metastasis. Urinary tract complications, progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) were evaluated using the Kaplan–Meier method and Cox regression analyses. ResultsPatients treated with RT showed higher prostate-specific antigen levels. There was no significant difference in the 5-year PFS (52.5% vs. 37.9%, p=0.351), CSS (67.6% vs. 84.7%, p=0.473), or OS (63.6% vs. 73.8%, p=0.897) between the RT and RP groups. In the multivariate analyses, the type of local therapy was not associated with PFS (hazard ratio [HR]=1.334, p=0.356), CSS (HR=0.744, p=0.475), or OS (HR=0.953, p=0.897). ConclusionTherefore, RP seems to be a possible treatment option for patients with omPC, exhibiting oncologic outcomes comparable to those with RT
Spicy Taste Rating of Chili Pepper and Kimchi
In order to introduce spicy taste ratings of Chilipepper(powdered) and Kimchi, many kinds of products incirculation were selected as specimens and the correlation of thesensory taste results and capsaicinoids contents were analyzed.When compared the spicy taste levels(capsaicinoids) of specimenswith their sensory test results, they were found that capsaicinoidscontent(capsaicin and dihydrocapsaicin) and sensory test resultshad a high correlation (R2) at more than 0.9 in HPLC analyzingmethod.Categorizing the pungency of the Chili pepper(powdered) intofive levels best reflected the status of Chili pepper products onthe market(mild hot, slight hot, medium hot, very hot, extremehot), while the Kimchi into three levels reflected the status ofKimchi products on the market(mild hot, medium hot, very hot).capsaicinoids contents of five levels in Chili pepper(powdered)were less than 150 mg/kg, 150~300 mg/kg, 300~500 mg/kg,500~1,000 mg/kg and more than 1,000 mg/kg. capsaicinoidscontents of three levels in Kimchi were less than 4 mg/kg, 4~12mg/kg, and more than 12 mg/kg
Clinical outcomes of FOLFIRINOX in locally advanced pancreatic cancer: A single center experience
Systemic chemotherapy or chemoradiotherapy is the initial primary option for patients with locally advanced pancreatic cancer (LAPC). This study analyzed the effect of FOLFIRINOX and assessed the factors influencing conversion to surgical resectability for LAPC.Sixty-four patients with LAPC who received FOLFIRINOX as initial chemotherapy were enrolled retrospectively. Demographic characteristics, tumor status, interval/dosage/cumulative relative dose intensity (cRDI) of FOLFIRINOX, conversion to resection, and clinical outcomes were reviewed and factors associated with conversion to resectability after FOLFIRINOX were analyzed.After administration of FOLFIRINOX (median 9 cycles, 70% of cRDI), the median patient overall survival (OS) was 17.0 months. Fifteen of 64 patients underwent surgery and R0 resection was achieved in 11 patients. During a median follow-up time of 9.4 months after resection, cumulative recurrence rate was 28.5% at 18 months after resection. The estimated median OS was significantly longer for the resected group (>40 months vs 13 months). There were no statistical differences between the resected and non-resected groups in terms of baseline characteristics, tumor status and hematologic adverse effects. The patients who received standard dose of FOLFIRINOX had higher probability of subsequent resection compared with patients who received reduced dose, although cRDIs did not differ between groups.FOLFIRINOX is an active regimen in patients with LAPC, given acceptable resection rates and promising R0 resection rates. Additionally, our data demonstrate it is advantageous for obtaining resectability to administer FOLFIRINOX without dose reduction
Interactions between Cells with Distinct Mutations in c-MYC and Pten in Prostate Cancer
In human somatic tumorigenesis, mutations are thought to arise sporadically in individual cells surrounded by unaffected cells. This contrasts with most current transgenic models where mutations are induced synchronously in entire cell populations. Here we have modeled sporadic oncogene activation using a transgenic mouse in which c-MYC is focally activated in prostate luminal epithelial cells. Focal c-MYC expression resulted in mild pathology, but prostate-specific deletion of a single allele of the Pten tumor suppressor gene cooperated with c-MYC to induce high grade prostatic intraepithelial neoplasia (HGPIN)/cancer lesions. These lesions were in all cases associated with loss of Pten protein expression from the wild type allele. In the prostates of mice with concurrent homozygous deletion of Pten and focal c-MYC activation, double mutant (i.e. c-MYC+;Pten-null) cells were of higher grade and proliferated faster than single mutant (Pten-null) cells within the same glands. Consequently, double mutant cells outcompeted single mutant cells despite the presence of increased rates of apoptosis in the former. The p53 pathway was activated in Pten-deficient prostate cells and tissues, but c-MYC expression shifted the p53 response from senescence to apoptosis by repressing the p53 target gene p21Cip1. We conclude that c-MYC overexpression and Pten deficiency cooperate to promote prostate tumorigenesis, but a p53-dependent apoptotic response may present a barrier to further progression. Our results highlight the utility of inducing mutations focally to model the competitive interactions between cell populations with distinct genetic alterations during tumorigenesis
A Reusable Fuzzy Extractor with Practical Storage Size
After the concept of a Fuzzy Extractor (FE) was rst introduced by Dodis et al. , it has
been regarded as one of the candidate solutions for key management utilizing biometric data. With
a noisy input such as biometrics, FE generates a public helper value and a random secret key which
is reproducible given another input similar to the original input. However, helper values may
cause some leakage of information when generated repeatedly by correlated inputs, thus reusability
should be considered as an important property. Recently, Canetti et al. (Eurocrypt 2016) proposed
a FE satisfying both reusability and robustness with inputs from low-entropy distributions. Their
strategy, the so-called Sample-then-Lock method, is to sample many partial strings from a noisy
input string and to lock one secret key with each partial string independently.
In this paper, modifying this reusable FE, we propose a new FE with size-reduced helper data
hiring a threshold scheme. Our new FE also satises both reusability and robustness, and requires
much less storage memory than the original. To show the advantages of this scheme, we analyze
and compare our scheme with the original in concrete parameters of the biometric, IrisCode. As a
result, on 1024-bit inputs, with false rejection rate 0.5 and error tolerance 0.25, while the original
requires about 1TB for each helper value, our scheme requires only 300MB with an additional
1.35GB of common data which can be used for all helper values
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