Development of a prediction model using fully connected neural networks in the analysis of composite structures under bird strike

Zehra Hasılcı,Muharrem Erdem Boğoçlu,Ahmet Selim Dalkılıç,Altan Kayran 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

Bird strike is one of the most hazardous issues facing global aviation. In the present study, a hybrid methodology is developed utilizing, automated data generation and fully connected neural networks to practically and reliably obtain the global deformation of composite structures subject to bird strike. The validation of the proposed numerical bird strike model is accomplished by making comparisons with the available experimental data from three different resources in the literature on the chicken and gelatine strike tests to a rigid plate, and strike test against an aircraft composite vertical leading edge. For three different bird velocities, 9402 input files are created by an automatic data generator considering all possible stacking sequence combinations in accordance with the composite design guidelines. The global deformation of composite laminates caused by bird strike is estimated via the fully connected neural networks established. Results of the present study show that with the use of fully connected neural networks, global deformation of the composite laminate can be estimated reliably and preliminary design of the composite laminate can be performed very fast compared to performing nonlinear finite element analysis involving bird strike. In conclusion, the fully connected neural network model is found to be an alternative for additional LS-Dyna simulations in the optimization process.

Relationships of Fall Risk With Frailty, Sarcopenia, and Balance Disturbances in Mild-to-Moderate Alzheimer’s Disease

Merve Güner Oytun,Semra Topuz,Arzu Okyar Baş,Süheyla Çöteli,Zeynep Kahyaoğlu,İlker Boğa,Serdar Ceylan,Burcu Balam Doğu,Mustafa Cankurtaran,Meltem Halil 대한신경과학회 2023 Journal of Clinical Neurology Vol.19 No.3

hence it commonly coexists with balance issues. Frailty and sarcopenia are intertwined and prevalent in dementia, and are closely related to falls. We aimed to determine the relationships of the fall risk with balance disturbances, sarcopenia, and frailty in mild-to-moderate Alzheimer’s disease (AD). Methods The study enrolled 56 patients with probable AD. A comprehensive geriatric assessment was performed, and muscle strength and mass, performance status, gait, and balance were evaluated. All parameters were compared between fallers and nonfallers with AD. Results Fallers comprised 53.6% of the study population. The demographic features and AD stages did not differ between fallers and nonfallers. Fallers were more frail than nonfallers (p<0.05). Frailty was found to be independently associated with fall history (odds ratio=2.15, 95% confidence interval=1.20–3.82, p=0.031). We found that falls were not associated with AD stage, muscle mass and function, balance and geriatric syndromes except urinary incontinence in patients with AD (p>0.05). Conclusions We found that falls were not influenced by AD stage. Both physical and cumulative frailty were strongly associated with falls in patients with mild-to-moderate AD.

Decreased Chitotriosidase Activity and Levels in Familial Mediterranean Fever

Halef Okan Doğan,Ahmet Omma,Turan Turhan,Nihal Boğdaycıoğlu,Yaşar Karaaslan,Hayrettin Yavuz,Özlem Demirpençe,Hüseyin Aydın,Sevtap Bakır 대한의학회 2016 Journal of Korean medical science Vol.31 No.12

Different studies have demonstrated changes in chitotriosidase (ChT) activity and concentrations in multiple diseases. However, changes in ChT activity and concentrations have not been concurrently evaluated in patients with Familial Mediterranean Fever (FMF). In this study, we analyzed the changes in serum ChT activity and concentrations in patients with FMF. The study included a total of 80 patients with FMF and 80 healthy controls. ChT enzyme activity and concentrations were measured and then compared between the groups. ChT activity was measured by using fluorometric ELISA and ChT concentrations were measured by using colorimetric ELISA methods. The median ChT activity was 10.00 (6.00–15.00) nmol/mL/hr in the patients and 14.00 (6.25–20.75) nmol/mL/hr in the controls. There was a statistically significant difference in the ChT activity between the controls and patients (P = 0.027). The median ChT concentrations were 65.40 (46.20–84.92) pg/mL and 125.00 (75.72–143.95) pg/mL in the patients and controls, respectively (P < 0.001), which were expressed as median percentiles (25th–75th). Additionally, we found no correlation between C-reactive protein and ChT activity (P = 0.978, r = 0.003) and concentrations (P = 0.446, r = −0.87). Serum ChT enzyme activity and concentrations may not be considered as a biomarker in FMF patients taking colchicine. New studies are needed to evaluate the changes of enzyme activity and concentration in colchicine-negative patients.

A Flexible Camera Calibration System for Mobile Platform

( Bo Lu ),( Taeg-keun Whangbo ),( Tae-kyu Han ) 한국정보처리학회 2013 한국정보처리학회 학술대회논문집 Vol.20 No.2

We propose a flexible camera calibration system for mobile platform to calibrate the camera's intrinsic parameters which based on the geometrical property of the vanishing points determined by two perpendicular groups of parallel lines. The system only requires the camera to observe a rectangle card show at a few(at least four)different orientation. The experimental results of the real images show the proposed calibration system in this paper is easy to use and robust.

Kinetic Monte Carlo modeling of 3D thin film growth on different substrates

Bo LU,Georgios ALMYRAS,Joseph GREENE,Kostas SARAKINOS 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Correlation of Adventitial Vasa Vasorum with Intracranial Atherosclerosis: A Postmortem Study

Lu Zheng,Wen Jie Yang,Chun Bo Niu,Hai Lu Zhao,Ka Sing Wong,Thomas Wai Hong Leung,Xiang Yan Chen 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.3

Background and Purpose Vasa vasorum (VV) have been believed to be rare or non-existent in small-caliber intracranial arteries. In a series of human cerebral artery specimens, we identified and examined the distribution of VV in association with co-existing intracranial atherosclerosis. Methods We obtained cerebral artery specimens from 32 consecutive autopsies of subjects aged 45 years or above. We scrutinized middle cerebral artery (MCA), vertebral artery (VA), and basilar artery (BA) for the presence of adventitial VV. We described the distribution of VV, and the characteristics of co-existing atherosclerotic lesions. Results Among 157 intracranial arteries, adventitial VV were present in 74 of the 157 specimens (47%), involving MCA (n=13, 18%), BA (n=14, 19%), and VA (n=47, 64%). Although qualitatively these 74 adventitial VV distributed similarly in arteries with or without atherosclerotic lesions (disease-free arteries n=4/8; arteries of pre-atherosclerosis n=17/42; and arteries of progressive atherosclerosis n=53/107), the presence of adventitial VV in intracranial VA was associated with a heavier plaque load (1.72±1.66 mm2 vs. 0.40±0.32 mm2, P<0.001), severer luminal stenosis (25%±21% vs. 12%±9%, P=0.002), higher rate of concentric lesions (79% vs. 36%, P=0.002), and denser intraplaque calcification (44% vs. 0%, P=0.003). Histologically, intracranial VA with VV had a larger diameter (3.40±0.79 mm vs. 2.34±0.58 mm, P<0.001), thicker arterial wall (0.31±0.13 mm vs. 0.23±0.06 mm, P=0.002), and a larger intima-media (0.19±0.09 mm vs. 0.13± 0.04 mm, P=0.003) than VA without VV. Conclusions Our study demonstrated the distribution of adventitial VV within brain vasculature and association between vertebral VV and progressive atherosclerotic lesions with a heavier plaque load and denser intraplaque calcification.

A Novel Endo-Polygalacturonase from Penicillium oxalicum: Gene Cloning, Heterologous Expression and Its Use in Acidic Fruit Juice Extraction

( Bo Lu ),( Liang Xian ),( Jing Zhu ),( Yunyi Wei ),( Chengwei Yang ),( Zhong Cheng ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.4

An endo-polygalacturonase (endo-PGase) exhibiting excellent performance during acidic fruit juice production would be highly attractive to the fruit juice industry. However, candidate endo-PGases for this purpose have rarely been reported. In this study, we expressed a gene from Penicillium oxalicum in Pichia pastoris. The recombinant enzyme PoxaEnPG28C had an optimal enzyme activity at pH 4.5 and 45℃ and was stable at pH 3.0-6.5 and < 45℃. The enzyme had a specific activity of 4,377.65 ± 55.37 U/mg towards polygalacturonic acid, and the K_m and V_max values of PoxaEnPG28C were calculated as 1.64 g/l and 6127.45 U/mg, respectively. PoxaEnPG28C increased the light transmittance of orange, lemon, strawberry and hawthorn juice by 13.9 ± 0.3%, 29.4 ± 3.8%, 95.7 ± 10.2% and 79.8 ± 1.7%, respectively; it reduced the viscosity of the same juices by 25.7 ± 1.6%, 52.0 ± 4.5%, 48.2 ± 0.7% and 80.5 ± 2.3%, respectively, and it increased the yield of the juices by 24.5 ± 0.7%, 12.7 ± 2.2%, 48.5 ± 4.2% and 104.5 ± 6.4%, respectively. Thus, PoxaEnPG28C could be considered an excellent candidate enzyme for acidic fruit juice production. Remarkably, fruit juice production using hawthorn as an material was reported for the first time.

Prenatal exposure to phencyclidine produces abnormal behaviour and NMDA receptor expression in postpubertal mice

Lu, Lingling,Mamiya, Takayoshi,Lu, Ping,Toriumi, Kazuya,Mouri, Akihiro,Hiramatsu, Masayuki,Kim, Hyoung-Chun,Zou, Li-Bo,Nagai, Taku,Nabeshima, Toshitaka Oxford University Press 2010 International Journal of Neuropsychopharmacology Vol.13 No.7

Operational Performance Evaluation of Korean Major Container Terminals

Lu, Bo,Park, Nam-Kyu Korean Institute of Navigation and Port Research 2010 한국항해항만학회지 Vol.34 No.9

As the competition among the container terminals in Korea has become increasingly fierce, every terminal is striving to increase its investments constantly and lower its operational costs in order to maintain the competitive edge and provide satisfactory services to terminal users. The unreasoning behavior, however, has induced that substantial waste and inefficiency exists in container terminal production. Therefore, it is of great importance for the terminal to know whether it has fully used its existing infrastructures and that output has been maximized given the input. From this perspective, data envelopment analysis (DEA) provides a more appropriate benchmark. This study applies three models of DEA to acquire a variety of analytical results about the operational efficiency to the Korean container terminals. According to efficiency value analysis, this study first finds the reason of inefficiency. It is followed by identification of the potential areas of improvement for inefficient terminals by applying slack variable method and giving the projection results. Finally, return to scale approach is used to assess whether each terminal is in a state of increasing, decreasing, or constant return to scale. The results of this study can provide terminal managers with insight into resource allocation and optimization of the operating performance.

Structural Performance of Earthquake-damaged Beams in Fire

Bo Wen,Lu Zhang,Bo Wu,Ditao Niu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12

Post-Earthquake Fire (PEF) on frame structures usually leads to complicated and unpredictable thermal performance of damaged concrete members. In order to determine the structural performance of seismic-damaged Reinforced Concrete (RC) beams under PEF conditions, the RC frame structures are subjected to the shake table test. The test, used in conjunction with other existing seismic hazard data, demonstrates that the main geometric damage forms of RC beams after the earthquake are cracks and concrete spalling. Subsequently, calculating models of PEF RC beams are established in ABAQUS, and then the distribution of thermal field, hightemperature bearing capacity and reduction coefficient of seismic-damaged beams are proposed respectively. From experimental and numerical investigations, It can conclude that (a) the simplified numerical models are proven to accurately determine the fire performance of the damaged RC beams; (b) the thermal performance degradation caused by spalling is more severe than the degradation caused by cracking on PEF RC beams, which demonstrates that spalling takes a more important role than cracking; and (c) the prediction equation of the flexural bearing capacity reduction factor of PEF RC beams is feasible.