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A substantial amount of money and time is required to optimize resources in a massive Wi-Fi network in a real-world environment. Therefore, to reduce cost, proposed algorithms are first verified through simulations before implementing them in a real-world environment. A traffic model is essential to describe user traffic for simulations. Existing traffic models are statistical models based on a discrete-time random process and combine a spatiotemporal characteristic model with the varying parameters, such as average and variance, of a statistical model. The spatiotemporal characteristic model has a mathematically strict assumption that the access points (APs) have approximately similar traffic patterns that increase during day times and decrease at night. The mathematical assumption ensures a homogeneous representation of the network traffic. It does not include heterogeneous characteristics, such as the fact that lecture buildings on campus have a high traffic during lectures, while restaurants have a high traffic only during mealtimes. Therefore, it is difficult to represent heterogeneous traffic using this mathematical model. Deep learning can be used to represent heterogeneous patterns. This study proposes a generative model for Wi-Fi traffic that considers spatiotemporal characteristics using deep learning. The proposed model learns the heterogeneous traffic patterns from the AP-level measurement data without any assumptions and generates similar traffic patterns based on the data. The result shows that the difference between the sample generated by the proposed model and the collected data is up to 72.1% less than that reported in previous studies.

One of the most promising approaches to address the mismatch between computation- intensive applications and computation-limited end devices is multi-access edge computing (MEC). To overcome the rapid increase in traffic volume and offload the traffic from macrocells, a massive number of small cells have been deployed, so-called heterogeneous networks (HetNets). Strongly motivated by the close integration of MEC and HetNets, in this paper, we propose an envisioned architecture of MEC-empowered HetNets, where both wireless and wired backhaul solutions are supported, flying base stations (BSs) can be equipped with MEC servers, and mobile users (MUs) need both communication and computation resources for their computationally heavy tasks. Subsequently, we provide the research progress summary of task offloading and resource allocation in the proposed MEC-empowered unmanned aerial vehicle (UAV)-assisted heterogeneous networks. We complete this article by spotlighting key challenges and open future directives for researches.

In this paper, the multi-step forming process was studied with the fine blanking (FB) tool and the FB experiments for the precise clutch cam of automobile seat lifer pumping device (PCC). In order to form the PCC, the multi-step compound FB tooling system was taken; the three forces were directly gained from the rams of the FB press and the other force was gained from the auxiliary hydraulic device in the FB press. The FB tool was optimally designed through the FB simulation and fabricated. From the FB experiments with the FB press (Mori Iron Co., Ltd, FB400), the 5 samples of the PCC were taken and measured. All samples fulfilled the tolerance conditions.

The wireless resources required by users have increased in parallel with and above improvements in WLAN technology, requiring even more accurate and practical resource management. Research on medium utilization, which is fundamental to resource management, has supplied insufficient evidence to apply it in real environments. This paper proposes a hybrid measurement approach to medium utilization using both a signal-level register monitor and a frame-level frame parser. We redefine medium utilization in terms of Medium Occupied Time (MOT) to describe the status of the medium in more detail. The proposed approach enables us to measure the classified MOT occupied by 802.11 frames, wireless interference, and a MAC protocol. We implement our approach by modifying a Linux device driver of an off-the-shelf 802.11n NIC. In addition, an indoor test bed is built to verify the approach’s support for various traffic patterns, quantitative measurement of wireless interference, and backoff time estimation. We conclude that our hybrid measurement approach is accurate and deployable in a real environment.

Background Myeloperoxidase (MPO) and human neutrophil lipocalin or neutrophil gelatinase-associated lipocalin (HNL/NGAL) are stored in neutrophil granulocytes and secreted upon activation of the cells. They have been proposed to reflect the degree of inflammation in the airways. However, their role as potential markers of disease severity in childhood asthma remains unknown. This study investigated the relationship between the expression of MPO and HNL/NGAL and childhood asthma. Methods A total of 83 pediatric patients with asthma and 59 controls were enrolled. Using enzyme-linked immunosorbent assays, the human MPO and HNL/NGAL levels were measured in sputum supernatants. Assessments including spirometry, methacholine challenge test, and atopy test were conducted. Results No difference in sputum neutrophil counts was observed between pediatric patients with asthma and controls. However, sputum MPO and HNL/NGAL levels were significantly higher in patients with asthma than in controls ( p  = 0.021 and p  < 0.001, respectively), especially in patients with moderate-to-severe persistent asthma. In patients with asthma, sputum MPO and HNL/NGAL levels showed a positive correlation with sputum neutrophil counts (MPO, r  = 0.433, p  < 0.001; HNL/NGAL, r  = 0.584, p  < 0.001) and with each other ( r  = 0.628, p  < 0.001). Moreover, sputum HNL/NGAL level demonstrated better ability to accurately reflect current pulmonary function, airway inflammation, and limitations than MPO level in this study. Conclusions Sputum MPO and HNL/NGAL levels, which reflect neutrophil activation in airways, were increased in pediatric patients with asthma. Moreover, sputum MPO and HNL/NGAL may serve as appropriate assessment indicators of asthma severity in pediatric patients.

The utilization of high-strength steel for automotive structural parts has increased since the oil crisis in the 1970s owing to its high strength and potential for weight reduction. Because of the limited formability of high-strength steels, automotive components are increasingly produced through hot press forming. In some instances, high-strength steel sheets are coated with an Al–Si layer in order to prevent scaling of components during hot press forming, and this can increase their reliability with a view to the dimensional accuracy and stress distribution when they are in service. In this contribution, the coating degradation mechanisms of Al–Si-coated boron steel after the hot bending process are reported. The issues related to coating degradation during hot press forming are critically reviewed at different positions on a part that was subject to hot bending. In addition, the hardness and friction coefficient were tested by a nano-indenter at various positions. The relationship between the experimental parameters and coating layer properties is also reported. It is concluded that the bending deformation affected the coating layer behavior the most.

Recurrent bacterial infection causes frequent bronchiectasis (BE) exacerbations. The effectiveness and safety of long-term administration of macrolides in BE remain controversial, especially in children who require minimal treatment to prevent exacerbation. We conducted this meta-analysis to determine the usefulness of long-term macrolide use in pediatric BE. We searched PubMed, Cochrane Library databases, Embase, KoreaMed, Igaku Chuo Zasshi, and Chinese National Knowledge Infrastructure databases. We identified randomized controlled trials (RCTs) which elucidated long-term macrolide treatment (≥ 4 weeks) in non-cystic fibrosis BE in children aged < 18 years. The primary outcome was frequency of acute exacerbation; secondary outcomes included changes in pulmonary function, sputum scores, and adverse events including bacterial resistance. We included four RCTs. Long-term macrolide treatment showed a significant decrease in the frequency of exacerbation (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.10–0.87), mean number of exacerbations per patient (mean difference, − 1.40; 95% CI, − 2.26 to − 0.54), and sputum purulence score (mean difference, − 0.78; 95% CI, − 1.32 to − 0.24). However, long-term macrolide treatment was accompanied by an increased carriage of azithromycin-resistant bacteria (OR, 7.13). Long-term macrolide administration prevents exacerbation of BE in children; however, there are risks of increasing antibiotic resistance. Benefits and risks should be weighed and determined on a patient-by-patient basis.

The single-hop star-of-stars topology in low-power and wide-area networks (LPWAN) exhibits reliability and substandard coverage issues, especially in urban areas where line-of-sight (LoS) communication is difficult to achieve. Moreover, LPWAN trade-off the data rate to achieve longer coverage, preventing other end-devices from using the time resource. Locating other gateways is uneconomical as it requires infrastructure, such as the internet and a power connection. In this study, we propose a forwarding scheme with a relay to increase LPWAN coverage and reliability while not degrading the network’s capacity. A relay tends to incur unnecessary forwarding that degrades the network capacity unless proper countermeasure is prepared. Our works, namely opportunistic and on-demand network coding (OODC), minimize unnecessary forwarding and make good use of multiple-receiving relays. Network coding is also applied in the relay for better transmission efficiency and reliability simultaneously. Because network coding occurs header overhead, we perform a header compression technique to counter it. According to our simulation result, our method shows better reliability than fixed path forwarding. In an adaptive data rate settings, the OODC achieves a 92% packet delivery ratio (PDR), whereas a fixed-path forwarding only achieves an 84% PDR.

An accurate method to predict the mortality in the intensive care unit (ICU) patients has been required, especially in children. The aim of this study is to evaluate the value of serum anion gap (AG) for predicting mortality in pediatric ICU (PICU). We reviewed a data of 461 pediatric patients were collected on PICU admission. Corrected anion gap (cAG), the AG compensated for abnormal albumin levels, was significantly lower in survivors compared with nonsurvivors ( p  < 0.001). Multivariable logistic regression analysis identified the following variables as independent predictors of mortality; cAG (OR 1.110, 95% CI 1.06–1.17; p  < 0.001), PIM3 [OR 7.583, 95% CI 1.81–31.78; p  = 0.006], and PRISM III [OR 1.076, 95% CI 1.02–1.14; p  = 0.008]. Comparing AUCs for mortality prediction, there were no statistically significant differences between cAG and other mortality prediction models; cAG 0.728, PIM2 0.779, PIM3 0.822, and PRISM III 0.808. The corporation of cAG to pre-existing mortality prediction models was significantly more accurate at predicting mortality than using any of these models alone. We concluded that cAG at ICU admission may be used to predict mortality in children, regardless of underlying etiology. And the incorporation of cAG to pre-existing mortality prediction models might improve predictability.

Noncystic fibrosis bronchiectasis is a chronic respiratory disease that carries high socioeconomic and medical burdens and is caused by diverse respiratory illnesses. To improve clinical outcomes, early recognition, active treatment of exacerbations, and prevention of further exacerbations are essential. However, evidence for the treatment and prevention of acute exacerbation of noncystic fibrosis bronchiectasis, especially in children, is lacking. Therefore, the evidence- and consensus-based guidelines for medical and nonmedical treatment strategies for noncystic fibrosis bronchiectasis in children and adolescents were developed by the Korean Academy of Pediatric Allergy and Respiratory Disease using the methods recommended by the Grading of Recommendations Assessment, Development, and Evaluation working group with evidence published through July 2, 2020. This guideline encompasses evidence-based treatment recommendations as well as expert opinions, addressing crucial aspects of the treatment and management of non-cystic fibrosis bronchiectasis in children. This includes considerations for antibiotics and airway clearance strategies, particularly in areas where evidence may be limited. Large, well-designed, and controlled studies are required to accumulate further evidence of management strategies for noncystic fibrosis bronchiectasis in children and adolescents.