5,891 research outputs found

    MILP Model For Network Revenue Management In Airlines

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    Seat inventory control is an important problem in revenue management which is to decide whether to accept or reject a booking request during the booking horizon in airlines. The problem can be modeled as dynamic stochastic programs, which are computationally intractable in network settings. Various researches have been tried to solve it effectively. Even though dynamic (and stochastic) programming (DP) models can be solved it optimally, they are computationally intractable even for small sized networks. Therefore, in practice, DP models are approximated by various mathematical programming models. In this paper, we propose an approximation model for solving airline seat inventory control problem in network environments. Using Linear Approximation technique, we will transform our problem into a concave piecewise LP model. Based on the optimal solution of ours, we suggest how to implement it for airline inventory control policies such as booking limits, bid-price controls and virtual nesting controls

    Development of the MICROMEGAS Detector for Measuring the Energy Spectrum of Alpha Particles by using a 241-Am Source

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    We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of {\alpha} particles from the 241-Am source can be varied by changing the flight path of the {\alpha} particle from the 241 Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the {\alpha} particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for {\alpha} particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that {\alpha} particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGAS detector for {\alpha} particles under the present conditions is found to be ~ 97.3 %

    Prognostic Value of Metastatic Tumoral Caveolin-1 Expression in Patients with Resected Gastric Cancer

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    Objective. Caveolin-1 (Cav-1), as the main component of caveolae, has complex roles in tumourigenesis in human malignancies. We investigated Cav-1 in primary and metastatic tumor cells of gastric cancer (GC) and its association with clinical outcomes. Methods. We retrieved 145 cases of GC who had undergone curative gastrectomy. The expression levels of Cav-1 was evaluated by immunohistochemistry, and its association with clinicopathological parameters and patient survival was analyzed. Results. High expression of Cav-1 protein of the GC in the stomach and metastatic lymph node was 12.4% (18/145) and 16.5% (15/91). In the multivariate analysis, tumoral Cav-1 protein in metastatic lymph node showed prognostic significance for relapse-free survival (RFS, HR, 3.934; 95% CI, 1.882–8.224; P=0.001) and cancer-specific survival outcome (CSS, HR, 2.681; 95% CI, 1.613–8.623; P=0.002). Among the GCs with metastatic lymph node, it remained as a strong indicator of poor prognosis for RFS (HR, 3.136; 95% CI, 1.444–6.810; P=0.004) and CSS (HR, 2.509; 95% CI, 1.078–5.837; P=0.032). Conclusion. High expression of tumoral Cav-1 protein in metastatic lymph node is associated with unfavorable prognosis of curative resected GC, indicating the potential of novel prognostic markers

    Federated Learning with Diffusion Models for Privacy-Sensitive Vision Tasks

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    Diffusion models have shown great potential for vision-related tasks, particularly for image generation. However, their training is typically conducted in a centralized manner, relying on data collected from publicly available sources. This approach may not be feasible or practical in many domains, such as the medical field, which involves privacy concerns over data collection. Despite the challenges associated with privacy-sensitive data, such domains could still benefit from valuable vision services provided by diffusion models. Federated learning (FL) plays a crucial role in enabling decentralized model training without compromising data privacy. Instead of collecting data, an FL system gathers model parameters, effectively safeguarding the private data of different parties involved. This makes FL systems vital for managing decentralized learning tasks, especially in scenarios where privacy-sensitive data is distributed across a network of clients. Nonetheless, FL presents its own set of challenges due to its distributed nature and privacy-preserving properties. Therefore, in this study, we explore the FL strategy to train diffusion models, paving the way for the development of federated diffusion models. We conduct experiments on various FL scenarios, and our findings demonstrate that federated diffusion models have great potential to deliver vision services to privacy-sensitive domains

    Characterisation of Pseudomonas aeruginosa related to bovine mastitis

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    Pseudomonas aeruginosa is one of the causative pathogens of bovine mastitis. Most P. aeruginosa strains possess the type III secretion system (TTSS), which may increase somatic cell counts (SCCs) in milk from mastitis-affected cows. Moreover, most of P. aeruginosa cells can form biofilms, thereby reducing antibiotic efficacy. In this study, the presence and effect of TTSS-related genotypes on increase of SCCs among 122 P. aeruginosa isolates obtained from raw milk samples from mastitis-affected cows and their antibiotic susceptibility at planktonic and biofilm status were investigated. Based on the presence of TTSS-related genes a total of 82.7% of the isolates were found to harbour exoU and/or exoS genes, including the invasive (exoU-/exoS+, 69.4%), cytotoxic (exoU+/exoS-, 8.3%) and cytotoxic/invasive strains (exoU+/ exoS+, 5.0%). Milk containing exoS-positive isolates had higher SCCs than those containing exoS-negative isolates. The majority of isolates showed gentamicin, amikacin, meropenem and ciprofloxacin susceptibility at planktonic status. However, the susceptibility was decreased at the biofilm status. Based on minimum biofilm eradication concentration (MBEC)/minimum inhibitory concentration (MIC) ratios, the range of change in antibiotic susceptibility varied widely depending on the antibiotics (from ≥ 3.1-fold to ≥ 475.0-fold). In conclusion, most P. aeruginosa isolates studied here had a genotype related to increase in SCCs. The efficiency of antibiotic therapy against P. aeruginosa-related bovine mastitis could be improved by analysing both the MBEC and the MIC of isolates

    Q-balls of Quasi-particles in a (2,0)-theory model of the Fractional Quantum Hall Effect

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    A toy model of the fractional quantum Hall effect appears as part of the low-energy description of the Coulomb branch of the A1A_1 (2,0)-theory formulated on (S1Ă—R2)/Zk(S^1\times R^2)/Z_k, where the generator of ZkZ_k acts as a combination of translation on S1S^1 and rotation by 2Ď€/k2\pi/k on R2R^2. At low energy the configuration is described in terms of a 4+1D Super-Yang-Mills theory on a cone (R2/ZkR^2/Z_k) with additional 2+1D degrees of freedom at the tip of the cone that include fractionally charged particles. These fractionally charged quasi-particles are BPS strings of the (2,0)-theory wrapped on short cycles. We analyze the large kk limit, where a smooth cigar-geometry provides an alternative description. In this framework a W-boson can be modeled as a bound state of kk quasi-particles. The W-boson becomes a Q-ball, and it can be described as a soliton solution of Bogomolnyi monopole equations on a certain auxiliary curved space. We show that axisymmetric solutions of these equations correspond to singular maps from AdS3AdS_3 to AdS2AdS_2, and we present some numerical results and an asymptotic expansion.Comment: 44 pages, 4 figures, new version includes corrections to typos and corrections to section

    Compact Asymmetrical Quasi-MMIC Doherty Power Amplifier

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    This paper presents a compact asymmetrical Doherty power amplifier (PA) based on a quasi-MMIC configuration for 5G sub-6 GHz applications. The proposed Doherty PA is composed of commercial GaN HEMTs and several passive components implemented on a silicon (Si) substrate. In order to achieve size and cost advantages, passive components such as a power divider, input matching networks, output matching networks, and a Doherty combiner are realized using Si-integrated passive device (Si-IPD) technology, which costs about 40% of the budget for the entire GaN MMIC process. For the 3.5 GHz pulsed-continuous waveform signal, the fabricated Doherty PA has an efficiency of 52.6% at a saturated output power of 44.2 dBm. Furthermore, an efficiency of 45.6% was achieved with the output power back-off (OBO) of 7.0 dB. The implemented PA occupies only 8.9 mm Ă— 5.6 mm
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