5,891 research outputs found
MILP Model For Network Revenue Management In Airlines
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
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
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
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
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Is poststroke complex regional pain syndrome the combination of shoulder pain and soft tissue injury of the wrist?: A prospective observational study STROBE of ultrasonographic findings in complex regional pain syndrome
Patients with poststroke complex regional pain syndrome (CRPS) show different symptoms compared to other types of CRPS, as they usually complain of shoulder and wrist pain with the elbow relatively spared. It is thus also known by the term “shoulder-hand syndrome.”
The aim of this study is to present a possible pathophysiology of poststroke CRPS through ultrasonographic observation of the affected wrist before and after steroid injection at the extensor digitorum communis (EDC) tendon in patients suspected with poststroke CRPS.
Prospective evaluation and observation, the STROBE guideline checklist was used.
Twenty-three patients diagnosed as poststroke CRPS in accordance to clinical criteria were enrolled. They had a Three Phase Bone Scan (TPBS) done and the cross-sectional area (CSA) of EDC tendon was measured by using ultrasonography. They were then injected with steroid at the EDC tendon. The CSA of EDC tendon, visual analogue scale (VAS), and degree of swelling of the wrist were followed up 1 week after the injection.
TPBS was interpreted as normal for 4 patients, suspected CRPS for 10 patients, and CRPS for 9 patients. Ultrasonographic findings of the affected wrist included swelling of the EDC tendon. After the injection of steroid to the wrist, CSA and swelling of the affected wrist compared to that before the treatment was significantly decreased (P < 0.001). The VAS score declined significantly after the injection (P < 0.001).
Our results suggest that the pathophysiology of poststroke CRPS might be the combination of frozen shoulder or rotator cuff tear of shoulder and soft tissue injury of the wrist caused by the hemiplegic nature of patients with stroke
Characterisation of Pseudomonas aeruginosa related to bovine mastitis
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
A toy model of the fractional quantum Hall effect appears as part of the
low-energy description of the Coulomb branch of the (2,0)-theory
formulated on , where the generator of acts as a
combination of translation on and rotation by on . At low
energy the configuration is described in terms of a 4+1D Super-Yang-Mills
theory on a cone () 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 limit, where a smooth cigar-geometry provides
an alternative description. In this framework a W-boson can be modeled as a
bound state of 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 to , 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
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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