1,801 research outputs found
The evaluation of pilots performance and mental workload by eye movement
Pilots make important decisions often using ambiguous information, while under stresses and with very little time. During flight operations detecting the warning light of system failure is a task with real-world application relates to measurement of pilot's performance and eye movement. The demand for a pilotās visual and situational awareness in multiple tasks can be detrimental during pilotsā mental overload conditions. The purpose of this research is to evaluate the relationship between pilotās mental workload and operational performance by eye tracking. Collecting eye movement data during flight operations in a virtual reality of flight simulator provided useful information to analysis participantsā cognitive processes. There were 36 pilots participated in this research, the experience of flight hours between 320 and 2,920, the range of age between 26 and 51 years old. The apparatus included Applied Science Laboratories (ASL) eye tracking, IDF flight simulator and NASA_TLX for data collection. The results show that pilots with high SA detecting hydraulic malfunction have shorter total fixation duration on Air Speed Indicator and longer total fixation duration on Altitude Indicator, Vertical Speed Indicator, Right multi-display and Left multi-display compared with pilots without detecting the signal of hydraulic malfunction. Pilotsā total fixation time on Integration Control Panel, Altitude Indicator, Attitude Indicator and Right Multi-display, and pilotsā subjective rating on NASA-TLX effort dimension for the mission of close pattern have significant relationship with pilotsā performance on the operational time for completing the tactic mission. Experienced pilots operate aircraft familiar with monitoring Airspeed Indicator and kinetic maneuvering result in less fuel consumption. This study could provide guidelines for future training design to reduce pilots mental workload and improve situational awareness for enhancing flight safety
Reexamining a single-producer multi-retailer integrated inventory model with rework using algebraic method
In this study, a single-producer multi-retailer integrated inventory model with rework is reexamined using mathematical modeling and an algebraic method. It is assumed that a product is manufactured through an imperfect production process, and the reworking of random defective items is done right after the regular process in each cycle. After the entire lot is quality assured, multiple shipments will be delivered synchronously to m different retailers in each production cycle. The objective is to find the optimal production lot size and optimal number of
shipments that minimizes total expected costs for such a specific supply chains system. The conventional approach uses differential calculus on system cost function to derive the optimal production- shipment policy (Chiu et al. [1]); in contrast, the proposed algebraic approach is a straightforward method that enables practitioners who may not have sufficient knowledge of calculus to understand and manage real-world systems more effectively
Production lot sizing with rework and fixed quantity deliveries
This paper is concerned with determination of the optimal lot size for an economic production quantity (EPQ) model with the reworking of random defective items and fixed quantity multiple deliveries. Classic EPQ model assumes continuous issuing policy for satisfying product demand and perfect quality production for all items produced. However, in real life vendor-buyer integrated production-inventory system, multi-delivery policy is used practically in lieu of the continuous issuing policy and generation of defective items during production run is inevitable. In this study, all nonconforming items produced are considered to be repairable and are reworked in each cycle when regular production ends. The finished items can only be delivered to customers if the whole lot is
quality assured at the end of the rework. Fixed quantity multiple installments of the finished batch are delivered to customers at a fixed interval of time. The long-run average integrated cost function per unit time is derived. A closed-form optimal batch size solution to the problem is obtained. A numerical example demonstrates its practical usage
An Electronic-Nose Sensor Node Based on a Polymer-Coated Surface Acoustic Wave Array for Wireless Sensor Network Applications
This study developed an electronic-nose sensor node based on a polymer-coated surface acoustic wave (SAW) sensor array. The sensor node comprised an SAW sensor array, a frequency readout circuit, and an Octopus II wireless module. The sensor array was fabricated on a large K2 128Ā° YX LiNbO3 sensing substrate. On the surface of this substrate, an interdigital transducer (IDT) was produced with a Cr/Au film as its metallic structure. A mixed-mode frequency readout application specific integrated circuit (ASIC) was fabricated using a TSMC 0.18 Ī¼m process. The ASIC output was connected to a wireless module to transmit sensor data to a base station for data storage and analysis. This sensor node is applicable for wireless sensor network (WSN) applications
Single-crystalline Ī“-Ni2Si nanowires with excellent physical properties
[[abstract]]In this article, we report the synthesis of single-crystalline nickel silicide nanowires (NWs) via chemical vapor deposition method using NiCl2Ā·6H2O as a single-source precursor. Various morphologies of Ī“-Ni2Si NWs were successfully acquired by controlling the growth conditions. The growth mechanism of the Ī“-Ni2Si NWs was thoroughly discussed and identified with microscopy studies. Field emission measurements show a low turn-on field (4.12 V/Ī¼m), and magnetic property measurements show a classic ferromagnetic characteristic, which demonstrates promising potential applications for field emitters, magnetic storage, and biological cell separation.[[notice]]č£ę£å®ē¢[[incitationindex]]SCI[[booktype]]é»åē[[booktype]]ē“
A single-producer multi-retailer integrated inventory model with a rework process
This study considers a single-producer multi-retailer integrated inventory model with the reworking of random defective items produced. The objective is to find the optimal production lot size and optimal number of shipments that minimizes total expected costs for such a specific supply chains system. It is assumed that a product is
manufactured by a producer. All items are screened for quality purpose and random nonconforming items will be picked up and reworked at the end of regular production in each cycle. After the entire lot is quality assured, multiple shipments will be delivered synchronously to m different retailers in each production cycle. Each retailer has its own annual product demand, unit stock holding cost, and fixed and variable delivery costs. Mathematical modeling and analysis is used to deal with the proposed model and to derive the expected system cost. Hessian
matrix equations are employed to prove the convexity of the cost function. As a result, a closed-form optimal replenishment-delivery policy for such a specific single-producer multi-retailer integrated inventory model is obtained. A numerical example is provided to show the practical usage of the proposed model
Sleep duration and patterns in Chinese older adults: A comprehensive meta-analysis
This meta-analysis examined the mean sleep duration and patterns in Chinese older adult population. A literature search was systematically conducted covering major English (PubMed, Embase and PsycINFO) and Chinese (Chinese National Knowledge Infrastructure (CNKI), WanFang and SinoMed) databases. Data in studies with the mean and standard deviation of sleep duration and/or the proportion of short and long sleep durations in Chinese older adults were extracted and pooled using random-effects models. Subgroup analyses were conducted according to gender, region, area, survey time and sample size. A total of 36 studies with 150,616 subjects were included for analyses. The pooled mean sleep duration of 21 studies with available data was 6.82 hours/day (95% CI: 6.59ā7.05 hours/day). The estimated proportions of sleep duration \u3c5 hours/day, \u3c6 hours/day, \u3c7 hours/day were 18.8% (95% CI: 1.7%ā35.9%), 26.7% (95% CI: 19.7%ā33.7%) and 42.3% (95% CI: 34.8%ā49.8%), respectively. The pooled proportions for long sleepers were 22.6% (95% CI: 13.9%ā31.4%) (\u3e8 hours/day) and 17.6% (95% CI: 12.4%ā22.9%) (\u3e9 hours/day). Given the adverse effects of unhealthy sleep patterns, health professionals should pay more attention to sleep patterns in this population in China
Analysis of clinical outcomes in pediatric bacterial meningitis focusing on patients without cerebrospinal fluid pleocytosis
BackgroundCerebrospinal fluid (CSF) cell count and biochemical examinations and cultures form the basis for the diagnosis of bacterial meningitis. However, some patients do not have typical findings and are at a higher risk of being missed or having delayed treatment. To better understand the correlation between CSF results and outcomes, we evaluated CSF data focusing on the patients with atypical findings.MethodsThis study enrolled CSF culture-proven bacterial meningitis patients aged from 1 month to 18 years in a medical center. The patients were divided into ānormalā and āabnormalā groups for each laboratory result and in combination. The correlations between the laboratory results and the outcomes were analyzed.ResultsA total of 175 children with confirmed bacterial meningitis were enrolled. In CSF examinations, 16.2% of patients had normal white blood cell counts, 29.5% had normal glucose levels, 24.5% had normal protein levels, 10.2% had normal results in two items, and 8.6% had normal results in all three items. In logistic regression analysis, a normal CSF leukocyte count and increased CSF protein level were related to poor outcomes. Patients with meningitis caused by Streptococcus pneumoniae and hyponatremia were at a higher risk of mortality and the development of sequelae.ConclusionsIn children with bacterial meningitis, nontypical CSF findings and, in particular, normal CSF leukocyte count and increased protein level may indicate a worse prognosis
Expression of Human papillomavirus type 52 L1 capsid gene in Oryza sativa involved in cytoprotective activities
Female cervical cancer is largely formed by Human papillomavirus (HPV), the second leading cause of cancer deaths in women worldwide. HPV-52 is a regionally common high-risk type of cervical cancer found mostly in Asia and reveals geographical variations, in order of importance, as types HPV-16 and -18. However, the differing propensities of HPV types in progressing to cancer, focusing on HPV-52 vaccines, are limited. Several plant-based vaccines against cancer have been developed, and the production of candidate HPV therapeutic vaccines using plant-derived expression platforms is also proven. The objectives of this study were to assess the HPV-52L1 Capsid gene by transferring HPV-52L1 Capsid cDNA into rice (Oryza sativa L.) via an Agrobacterium-mediated transformation, and accumulating HPV-52L1 Capsid proteins in a plant-based expression system to maintain and improve antigenicity. Crude protein extracts containing 5~20 Ī¼g from OsHP-52L1 transgenic lines induced cell death and significantly reduced cell proliferation in HPV-positive HeLa cervical cancer cells compared with those non-transformant (NT) rice plants. However, no significant cytotoxicity of induced human breast MDA-MB-231 cell proliferation (as negative control) was observed at any dose compared with NT groups. HeLa cells ameliorated the effects of OsHPV crude protein extracts on cell viability as the extract concentration increased, and treatment with 20 Ī¼g of the extract from OsHPV-3 significantly reduced cell viability in HeLa cells (26%) compared with the control group (57%). Our results can be used for exploring the potential of plants for increasing the immunogenicity of OsHPV-52L1 Capsid DNA vaccines, and support the development of cost-effective HPV vaccines, which is highly desirable for resource-poor countries
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