• Journal of the Ergonomics Society of Korea
• /
• v.36 no.5
• /
• pp.535-543
• /
• 2017

Objective: This study was designed to identify factors affecting pilots' +Gz tolerance recovery from +Gz induced exhaustion. Background: +Gz tolerance of pilots has been considered as a crucial factor to fly the modern high performance fighter aircrafts. However, the factors affecting pilots' G-tolerance recovery from +Gz induced exhaustion have not been examined in the acceleration research community. Method: A centrifuge profile consisting of a high +Gz run for pilot's exhaustion and a low +Gz run for pilot's recovery and another high +Gz runs for pilot's second exhaustion was designed. The subjects' +Gz tolerance recovery ratio was measured by ratio of second high +Gz run time to the first high +Gz run time. The subjects' +Gz tolerance recovery rate was measured by dividing the subjects' +Gz tolerance recovery ratio by the low +Gz run time. The subjects' G-tolerance recovery rate was analyzed with respect to the subjects' personal factors including subjects' anthropometric and physiologic characteristics, flight time, flying aircraft type and so on. Results: The subjects' previous three-month flight hours (r=-0.336, p=0.039), six-month flight hours (r=-0.403, p=0.012) and one-year flight hours (r=-0.329, p= 0.044) correlated with the subjects' G-tolerance recovery rate. Conclusion: The subjects' G-tolerance recovery rate is clearly related to the subjects' previous flight hours. However, the subjects' anthropometric and physiologic characteristics do not show any statistically significant correlation with the subjects' G-tolerance recovery rate. Application: This research provides a safety critical insight to aviation community by identifying the factors to affect the gravity-induced loss of consciousness (GLOC) of pilots.

• The Plant Pathology Journal
• /
• v.27 no.1
• /
• pp.20-25
• /
• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• Journal of the Ergonomics Society of Korea
• /
• v.15 no.1
• /
• pp.69-78
• /
• 1996

Current fighter pilots, flying new generation aircrafts with high performance, are under severe stress during aerial combat maneuvering when they are exposed to high sustained +Gz(Head-to-foot) acceleration stress. Two major factor limiting performance during high sustaied +Gz acceleration stress are loss of vision-greyout or blackout, and loss of consciousness (LOC). These symptoms are believed to occur as a result of insuff- icient blood flow to the retina and the brain. This study was conducted to evaluate the effects of high sustained +Gz stress under different seat back angle. The results. obtained by the biodvanmic computer simulations using the ATB(articulated total body) model, are represented with respect to three variables, such as HIC(head injury criterion) value, average G, and maximum G. The results demonstrate that the seat back angle(over $30^{\circ}C$) had a significant effect to decrease +Gz stress on the head segment and had no significant effect on HIC.

• Journal of Korea Foundry Society
• /
• v.36 no.2
• /
• pp.60-66
• /
• 2016

In this study, comparison of corrosion properties of the Mg-1.5Ge-1Zn (GZ21) alloy and Mg-9Al-1Zn (AZ91) alloy were investigated. The studied alloys were fabricated by permanent mold casting method. And the potentiodynamic test, hydrogen evolution test, immersion test and A.C Impedance test were carried out in a 3.5% NaCl solution with pH7.2 at room temperature to measure the corrosion properties. The microstructure of GZ21 alloy was composed of ${\alpha}-Mg$ and $Mg_2Ge$ phases and AZ91 alloy was composed of ${\alpha}-Mg$ and $Mg_{17}Al_{12}$ phases. From the test results, the corrosion property was improved by adding Ge. It seemed that the corrosion mechanism was changed from galvanic corrosion (AZ91) to filiform corrosion (GZ21).

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2005.04a
• /
• pp.84-85
• /
• 2005

• The Plant Pathology Journal
• /
• v.27 no.4
• /
• pp.301-309
• /
• 2011

The filamentous fungus Fusarium graminearum is an important cereal pathogen. Although quantitative realtime PCR (qRT-PCR) is commonly used to analyze the expression of important fungal genes, no detailed validation of reference genes for the normalization of qRT-PCR data has been performed in this fungus. Here, we evaluated 15 candidate genes as references, including those previously described as housekeeping genes and those selected from the whole transcriptome sequencing data. By a combination of three statistical algorithms (BestKeeper, geNorm, and NormFinder), the variation in the expression of these genes was assessed under different culture conditions that favored mycelial growth, sexual development, and trichothecene mycotoxin production. When favoring mycelial growth, GzFLO and GzUBH expression were most stable in complete medium. Both EF1A and GzRPS16 expression were relatively stable under all conditions on carrot agar, including mycelial growth and the subsequent perithecial induction stage. These two genes were also most stable during trichothecene production. For the combined data set, GzUBH and EF1A were selected as the most stable. Thus, these genes are suitable reference genes for accurate normalization of qRT-PCR data for gene expression analyses of F. graminearum and other related fungi.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.1 no.1
• /
• pp.27-38
• /
• 1995

In this paper, a program for the calculation of GZ curve for a ship in waves is developed and GZ curves for a ferry in the still water and in waves are calculated. And the added mass, damping, restoring forces and wave exciting forces are calculated by using the strip theory given by Salvesen, Tuck, Faltinsen. Capsizing simulations are perfoned in consideration if the nonlinear restoring forces of the ship in waves by using the Runge-Kutta 4-th method.

• Journal of Digital Convergence
• /
• v.16 no.5
• /
• pp.399-406
• /
• 2018

Much research has been done using the KDDCup99 data set to study intrusion detection using artificial intelligence. Previous studies have shown that the performance of the SMO (SVM) algorithm is superior. However, intrusion detection studies of new intrusion types not used in training are insufficient. In this paper, a model was created using the instances of weka's SMO and KDDCup99 training data set, kddcup.data.gz. We tested existing instances(292,300) of the corrected.gz file and new intrusions(18,729). In general, intrusion labels not used in training are not tested, so new intrusion labels were changed to normal. Of the 18,729 new intrusions, 1,827 were classified as intrusions. 1,827 instances classified as new intrusions are buffer_overflow. Three, neptune. 392, portsweep. 164, ipsweep. 9, back. 511, imap. 1, satan. Dogs, 645, nmap. 102.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.9 no.4
• /
• pp.287-292
• /
• 1976

The author studied the stability Tualities of stern trawlers in the North Pacific Ocean according to Kato's simple judging method. The author selected 1,000 gross tonnage of A and B types, and calculated each characteristics for various conditions under 5 different free-board and S different KG. Finally, authour obtained some data of stability factors for the two types, and pointed out the zone of safety and danger between stability factor, GM and GZ max. The results obtained here are summarized as follows: The A type of ship is judged that it has the condition of safety when displacement is 2,400 tonnage and the value of K￠ was 3.40m or 3.70m. The B type of ship is judged that it only has the condition of some safety when displacement was 2,400 tonnage and the value of KG is 3.40 m, but ships of the both types have the condition of danger when displacement is 1,300-2,200 tonnage and the value of KG is 3.40-4.60m. Any types of ships under various condition must have appropriate dimensions among GM, free-oard and GZ max for the stability of ships.

• Journal of the Society of Naval Architects of Korea
• /
• v.52 no.3
• /
• pp.187-197
• /
• 2015

This study aims the development of a semi-analytic method for the parametric roll of large containerships advancing in longitudinal waves. A 1.5 Degree-of-Freedom(DOF) model is proposed to account the change of transverse stability induced by wave elevations and vertical motions (heave and pitch). By approximating the nonlinearity of restoring moment at large heel angles, the magnitude of roll amplitude is predicted as well as susceptibility check for parametric roll occurrence. In order to increase the accuracy of the prediction, the relationship between righting arm(GZ) and metacentric height(GM) is examined in the presence of incident waves, and then a new formula is proposed. Based on the linear approximation of the mean and first harmonic component of GM, the equation of parametric roll in irregular wave excitations is introduced, and the computational results of the proposed model are validated by comparing those of weakly nonlinear simulation based on an impulse-response-function method combined with strip theory. The present semi-analytic doesn’ t require heavy computational effort, so that it is very efficient particularly when numerous sea conditions for the analysis of parametric roll should be considered.