A Probability-based Evolutionary Algorithm with Mutations to Learn Bayesian Networks

Bayesian networks are regarded as one of the essential tools to analyze causal relationship between events from data. To learn the structure of highly-reliable Bayesian networks from data as quickly as possible is one of the important problems that several studies have been tried to achieve. In recent years, probability-based evolutionary algorithms have been proposed as a new efficient approach to learn Bayesian networks. In this paper, we target on one of the probability-based evolutionary algorithms called PBIL (Probability-Based Incremental Learning), and propose a new mutation operator. Through performance evaluation, we found that the proposed mutation operator has a good performance in learning Bayesian networks

Experimental Assessment on Performance of a Heat Pump Cycle Using R32/R1234yf and R744/R32/R1234yf

     Hydro-fluorocarbons (HFCs) are widely used as working fluids (refrigerants) in air-conditioning and refrigeration systems. However, at the 1997 Kyoto Conference (COP3), it was determined that the product and use of HFCs should be regulated due to their high global warming potential (GWP). In the above mentioned situation for the air-conditioning and refrigeration systems, recently, R1234yf having extremely low-GWP was nominated as one of the alternates of HFCs. Some literatures reported that the heating capacity of heat pump cycles using R1234yf is less than R410A because of its smaller vapor density and latent heat. To achieve the performance comparable to R410A, much larger unit is required. Therefore, in this present study, mixing with R32 of larger latent heat and relatively low-GWP into R1234yf was attempted. Additionally, R744 having higher vapor density and extremely low-GWP was added into R32/R1234yf.  The R32/R1234yf and R744/R32/R1234yf are zeotropic mixtures that cause temperature change during the phase-change, typically called temperature glide. When this temperature glide is utilized effectively to decrease the irreversible loss in heat exchanger, the cycle performance can be improved. The degree of temperature glide is determined by the composition of refrigerant mixtures. The composition of the test refrigerants are selected from the criterions of GWPs just below 300 and 200.Experiment was conducted with a vapor compression heat pump cycle using a compressor developed for R410A. The condenser and the evaporator are tube-in tube heat exchangers of counter-flow configuration.  At compositions with GWP200 and a given heating capacity, the COP of R32/R1234yf and R744/R32/R1234yf are lower than that of R410A. The main causes were that R32/R1234yf of GWP200 has lower vapor density and R744/R32/R1234yf of GWP200 has lager temperature glide. At compositions with GWP300, R32/R1234yf and R744/R32/R1234yf exhibit comparable COP and heating capacity to R410A. Using R32/R1234yf and R744/R32/R1234yf of compositions with GWP300, as the alternatives of R410A, is feasible idea

チュウゴクゴ ノ カノウ ホゴ トクリョウ フリョウ ト トク フトク : カノウ ト モダリティ

PDF/A形式により利用可能アクセス:WWWによる東京外国語大学大学院総合国際学研究科博士 (学術) 論文 (2013年11月)博甲第173号参考文献: p206-213その他のタイトルは英文要旨による東京外国語大学 (Tokyo University of Foreign Studies)博士 (学術

Synthesis of ordered mesoporous ruthenium by lyotropic liquid crystals and its electrochemical conversion to mesoporous ruthenium oxide with high surface area

In ordered to prepare high capacitance pseudo-capacitive oxides, it is important to design nanostructures with appreciable mesopores. Supramolecular templating has become a popular method to synthesize ordered mesoporous metals; however, the application of the same technique to synthesis of high surface area oxides is more demanding. We present here, the synthesis of ordered mesoporous ruthenium metal by lyotropic liquid crystal templating and its electrochemical conversion to ordered mesoporous ruthenium oxide by a simple, room temperature procedure. The bulk, unsupported metallic ordered mesoporous ruthenium exhibits high surface area of 110 m(2) g(-1), which is comparable to typical supported Ru nanoparticles. The oxide analogue gives a high specific capacitance of 376 Fg(-1), owing to the porous structure. These results demonstrate a possible facile and generic process to synthesize oxides with ordered nanostructures by utilization of the various phases that can be obtained with lyotropic liquid crystalline templates such as cubic, hexagonal, lamellar, etc.ArticleJOURNAL OF POWER SOURCES. 204:244-248 (2012)journal articl

Nature and Clinical Outcomes of Acute Hemorrhagic Rectal Ulcer

Acute hemorrhagic rectal ulcer (AHRU) is a relatively rare disease that can lead to massive hematochezia. Although AHRU is a potentially life-threatening disease, its characteristics and clinical course are not fully understood. In this study, the clinical features were compared between AHRU and lower gastrointestinal bleeding (LGIB) from other causes (non-AHRU). Then, risk factors for all-cause in-hospital mortality in patients with AHRU were identified. A total of 387 consecutive adult patients with LGIB who were managed at two tertiary academic hospitals in Akita prefecture in Japan were retrospectively enrolled. Subjects were divided into AHRU and non-AHRU groups according to the source of bleeding. Regression analyses were used to investigate significant associations, and the results were expressed as odds ratios (ORs) and 95% confidence intervals (CIs). AHRU was found as the bleeding source in 72 (18.6%) of the patients. In comparison to non-AHRU, having AHRU was significantly associated with in-hospital onset, age > 65 years, and systolic blood pressure < 90 mmHg. The AHRU group had a significantly higher in-hospital mortality rate in comparison to the non-AHRU group (18.0% vs. 8.3, p = 0.02), and hypoalbuminemia (<2.5 g/dL) was significantly associated with in-hospital mortality in the AHRU group (OR, 4.04; 95%CI, 1.11-14.9; p = 0.03). AHRU accounts for a substantial portion (18.6%) of LGIB in our area, where the aging rate is the highest in Japan. Since AHRU is a potentially life-threatening disease that requires urgent identification and management, further studies to identify robust risk factors associated with serious clinical outcomes are required

Usefulness of the CHAMPS score for risk stratification in lower gastrointestinal bleeding

We have recently developed a simple prediction score, the CHAMPS score, to predict in-hospital mortality in patients with upper gastrointestinal bleeding. In this study, the primary outcome of this study was the usefulness of the CHAMPS score for predicting in-hospital mortality with lower gastrointestinal bleeding (LGIB). Consecutive adult patients who were hospitalized with LGIB at two tertiary academic medical centers from 2015 to 2020 were retrospectively enrolled. The performance for predicting outcomes with CHAMPS score was assessed by a receiver operating characteristic curve analysis, and compared with four existing scores. In 387 patients enrolled in this study, 39 (10.1%) of whom died during the hospitalization. The CHAMPS score showed good performance in predicting in-hospital mortality in LGIB patients with an AUC (95% confidence interval) of 0.80 (0.73-0.87), which was significantly higher in comparison to the existing scores. The risk of in-hospital mortality as predicted by the CHAMPS score was shown: low risk (score = 4), 37.1%. The CHAMPS score is useful for predicting in-hospital mortality in patients with LGIB

Role of cyclooxygenase-2-mediated prostaglandin E2-prostaglandin E receptor 4 signaling in cardiac reprogramming

Direct cardiac reprogramming from fibroblasts can be a promising approach for disease modeling, drug screening, and cardiac regeneration in pediatric and adult patients. However, postnatal and adult fibroblasts are less efficient for reprogramming compared with embryonic fibroblasts, and barriers to cardiac reprogramming associated with aging remain undetermined. In this study, we screened 8400 chemical compounds and found that diclofenac sodium (diclofenac), a non-steroidal anti-inflammatory drug, greatly enhanced cardiac reprogramming in combination with Gata4, Mef2c, and Tbx5 (GMT) or GMT plus Hand2. Intriguingly, diclofenac promoted cardiac reprogramming in mouse postnatal and adult tail-tip fibroblasts (TTFs), but not in mouse embryonic fibroblasts (MEFs). Mechanistically, diclofenac enhanced cardiac reprogramming by inhibiting cyclooxygenase-2, prostaglandin E2/prostaglandin E receptor 4, cyclic AMP/protein kinase A, and interleukin 1β signaling and by silencing inflammatory and fibroblast programs, which were activated in postnatal and adult TTFs. Thus, anti-inflammation represents a new target for cardiac reprogramming associated with aging