• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.12
• /
• pp.1045-1055
• /
• 2013

It is true that the dependency on import is currently high in case of the safety checkup system of domestic airplanes, and it is at the point of time that localization of HUMS for small airplanes is required. In this study, the design factors were selected for the lightweight of HUMS for small airplanes by using Pro-Engineer which is a design tool and Abaqus. 9 models were made through experiment plans with Taguchi method for this, and the each model for weight lightening was selected through vibration analysis and shock analysis while in operation with experiment profile values. After fabricating HUMS, it was verified that as a result of experiment with the same profile values as the analysis, there was similarity between the analyzed values and values of the experiment. As a result of performing weight lightening which is the purpose of the study, electronic performance for small airplanes is assured and a design plan reducing 15 % weight compared to the targeted weight was deduced. Besides, it could be verified that the light weight model satisfied the maximum allowable displacement value of PCB[printed circuit board] and accordingly satisfied electronic properties of HUMS. In this study, the reliability of a product was certified through the result of an experiment on ground. If the reliability of HUMS were verified through a test flight in the future, it is considered that it would make a big contribution to localization of aerospace electronic equipment.

• Current Industrial and Technological Trends in Aerospace
• /
• v.8 no.2
• /
• pp.105-112
• /
• 2010

Aircraft accidents are characterized by substantial and extensive damage: the destruction of hulls and the fatalities of passengers. Health and Usage Monitoring Systems (HUMSs) are being developed as a technological approach to prevent the aircraft accident. In Korea, a project to develop HUMS for small airplane is being executed by funding of by Ministry of Land, Transport and Maritime Affairs. In this paper, global R&D trends of HUMS to prevent aircraft accident are described. An on-going Korean HUMS project is also explained, especially for system configuration, functionality and expected achievement.

• Aerospace Engineering and Technology
• /
• v.11 no.1
• /
• pp.178-184
• /
• 2012

In this study, implementation process of sensor-embedded main wing model for structural health monitoring is described. Fiber Bragg Grating (FBG) Sensor, Plumbum-Zirconate-Titanate (PZT) Sensor, and strain gauge are installed in the main wing of Jabiru UL airplane as a test-bed of Health and Usage Monitoring System (HUMS).

• JOURNAL OF ELECTRICAL WORLD
• /
• s.405
• /
• pp.87-90
• /
• 2010

• Journal of Advanced Navigation Technology
• /
• v.20 no.5
• /
• pp.446-452
• /
• 2016

The aircraft has to be considered for safety very importantly because of peculiarity of flight in the air, so it should be retained through proper inspection and maintenance not only in production phase but also in operating phase. Recently, it is using the latest technology as engineering approach not depending on human factor to determine on maintenance needs, and domestic production rotary aircraft also has the health & usage monitoring system to measure and to monitor major components. However, continued vibration exceedance phenomenon occurred in production and operation phase because of inappropriate thresholds, and it confirmed as false alarm which is not necessary to repair. In this paper, it is described that operational concept of HUMS, and especially it contains a study result for efficiency of aircraft operation and ultimately the improvement of flight safety by optimizing HUMS thresholds to determine efficiently necessity of maintenance under limited conditions and by establishing inspection/maintenance procedures when the re-designated thresholds exceedance occurred.

• Parasites, Hosts and Diseases
• /
• v.47 no.1
• /
• pp.61-63
• /
• 2009

Although Toxoplasma gondii infection generally shows subclinical courses in adults, it may have severe pathologic effects on the fetus. For a survey of toxoplasmosis in Shahr-e-Rey area, south of Tehran, Iran, we conducted a serological study on 1,187 general populations using indirect fluorescent antibody (IFA) test. In this cross sectional study, cases were selected randomly by a local primary health care (PHC) system. Blood samples were collected in microcapillary tubes and sera were examined by IFA after centrifugation. It has been shown that 68.3% of cases in all age groups had IFA titer of 1:10 and higher, which we consider as positive cases, and the rate for 1:400 or over was 30.2%. There was meaningful correlation between anti-Toxoplasma antibody titers and age, sex, and occupation of subjected people (P < 0.05%). The incidence was higher in females and highest in the children age group (10-14 years old). The present study demonstrates high prevalence of Toxoplasma infection among the people in south of Tehran, Iran.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.9
• /
• pp.767-773
• /
• 2018

In many cases, modern aircraft are equipped with data acquisition system which checks the structural integrity of the aircraft. The analysis of the vibration data collected with the system is generally performed in dependence on a skilled expert who is familiar with aircraft design. Therefore, it is difficult to provide a representative and objective defect identification standard for general users. In this paper, we shows that it is possible to identify the type of maneuvers and faults by using the Principal Component Analysis(PCA) method in the vast vibration data collected during aircraft operation without using the existing aircraft design analysis. We classified the ROK Army aircraft vibration data for maneuvers and faults types, and applied the PCA to the classified data. Our result shows that it is possible to develop an objective maneuver/fault identification method without design analysis for general users.

• Food Science and Preservation
• /
• v.6 no.2
• /
• pp.173-178
• /
• 1999

This study was conducted to investigate the quality changes of Chinese cabbage with various storage methods. The V/H ratio, as reference of withering, of Chinese cabbage in PE film was high. Ethanol contents of Chinese cabbage packed with 0.06mm and 0.1mm PE film pouch were greater than that with 0.03mm PE film pouch. Organic acid and sugar contents in the Chinese cabbage were gradually decreased during storage. Chinese cabbage packed with 0.03mm PE film pouch was more adaptable than 0.06mm PE film pouch in winter Chinese cabbage during storage. The CO$_2$ contents in PE film pouch was increased hums 15days of storage, and then not changed during storage. The change of O$_2$ contents in PE film Pouch was opposed to tendency of CO$_2$ change. The 0.06mm and 0.1mm PE film Pouch high CO$_2$ contents and low O$_2$ contents during the storage, were less adaptable than 0.03mm PE film pouch in the winter Chinese cabbage storage.