• Environmental Analysis Health and Toxicology
• /
• v.25 no.2
• /
• pp.99-109
• /
• 2010

The distribution of ambient air particles varies according to climate, industries, and other sources. In this study, ambient air particles (less than 12.1 ${\mu}m$) were monitored from February to August, 2007 as 12 different fractions sorted by a cascade impactor. Particles in the size range from 0.33 ${\mu}m$ to 0.76 ${\mu}m$ comprised the main fraction of ambient air particles in Seoul, Korea. On the day of an Asian dust event, the particle fraction size increased to 1.25~2.5 ${\mu}m$. The different sized particle fractions were also monitored for metals and were found to contain toxic heavy metals including Pb, Cd, Hg, Cr and As. Particle preparations were significantly cytotoxic when exposed to cultured BEAS-2B cells. Microarray analysis of the treated cells indicated a significant up-regulation of a number of genes associated with oxidative stress, including metallothionein, heme oxygenase-1, heat shock protein 70, and NAD(P)H dehydrogenase-1.

• Journal of Environmental Impact Assessment
• /
• v.18 no.6
• /
• pp.393-399
• /
• 2009

The water of rivers and lakes are affecting by point and nonpoint source pollutions. The point source pollution can be controlled by establishing the treatment plants. However, nonpoint source pollution by various human activities is not easy to be controlled because it is difficult to determine the exits of the water flow and have many exit points. Due to contribution of nonpoint source pollution, the achievement ratio of water quality in rivers and lakes is not high. TMDL is the outstanding water quality control policy because all of the pollutant loadings from the watershed area are counting on the input loads. Our aqua-ecosystem has self-purification process by biological, physical and ecological processes. The self-purification process can remove the pollutant load from background concentrations. Usually forest area is main source of background concentrations. In Korea, about 70% of the national boundary area consists of mountains. This study is conducting as part of long-term monitoring to determine the Event Mean Concentration during a storm. The monitoring was performed on a broad-leaved tree area.

• Journal of the korean society of oceanography
• /
• v.37 no.3
• /
• pp.144-153
• /
• 2002

This is a review paper, assessing progress reported in a Special Issue (Prandle and Lane, 2000) of Coastal Engineering focusing on simulation of SPM in the North Sea, against issues over a diverse range of shelf seas and their coastal margins. The broad objectives of reproducing the characteristics of sediment fluxes off an open coast and relating these to tidal and wave forcing were achieved. However, accurate computation of these fluxes remains sensitive to largely empirical coefficients used in determining erosion and deposition rates. Bed roughness strongly influences both these coefficients and the associated near-bed current magnitudes (including wave impact thereon). Bed roughness can change significantly over a tidal cycle and dramatically over seasons or in the course of a major event. Accurate simulation of sediment fluxes on a day-to-day basis is constrained by dependency on the initial distribution of mobile sediments. The latter depends on rates and locations of original sources and the time history of preceding events. Remote sensing via aircraft could provide data for assimilation into such models to circumvent these constraints. The approaches described here can be readily applied to other coastal regions to indicate the likely distributions and pathways of known sediment sources. However quantitative simulations will require an associated observational programme. A subsequent stage is to understand the evolving balance between the forecasted sediment movement - the resulting morphological adjustments and thence modifications to the prevailing tidal current and wave regimes.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.32 no.3
• /
• pp.269-275
• /
• 2012

Carbon-fiber reinforced plastic(CFRP) laminates made of nano-particle-coated carbon fibers and damaged by a simulated lightning strike were tested under compression-after-impact(CAI) mode, during which the damage progress due to compressive loading has been monitored by acoustic emission(AE). The impact damage was induced not by mechanical loading but by a simulated lightning strike. Conductive nano-particles were coated directly on the fibers, from which CFRP coupons were made. The coupon were subjected to the strikes with a high voltage/current impulse of 10~40 kA within a few ${\mu}s$. The effects of nano-particle coating and the degree of damage induced by the simulated lightning strikes on AE activities were examined, and the relationship between the compressive residual strength and AE behavior has been evaluated in terms of AE event counts and the onset of AE activity with the compressive loading. The degree of impact damage was also measured in terms of damage area by using ultrasonic C-scan images. The assessment during the CAI tests of damaged CFRP showed that AE monitoring appeared to be useful to differentiate the degree of damage hence the mechanical integrity of composite structures damaged by lightning strikes.

• Nuclear Engineering and Technology
• /
• v.44 no.4
• /
• pp.393-404
• /
• 2012

After the Fukushima nuclear accident in 2011, there has been increasing concern regarding severe accidents in nuclear facilities. Severe accident scenarios are difficult for operators to monitor and identify. Therefore, accurate prediction of a severe accident is important in order to manage it appropriately in the unfavorable conditions. In this study, artificial intelligence (AI) techniques, such as support vector classification (SVC), probabilistic neural network (PNN), group method of data handling (GMDH), and fuzzy neural network (FNN), were used to monitor the major transient scenarios of a severe accident caused by three different initiating events, the hot-leg loss of coolant accident (LOCA), the cold-leg LOCA, and the steam generator tube rupture in pressurized water reactors (PWRs). The SVC and PNN models were used for the event classification. The GMDH and FNN models were employed to accurately predict the important timing representing severe accident scenarios. In addition, in order to verify the proposed algorithm, data from a number of numerical simulations were required in order to train the AI techniques due to the shortage of real LOCA data. The data was acquired by performing simulations using the MAAP4 code. The prediction accuracy of the three types of initiating events was sufficiently high to predict severe accident scenarios. Therefore, the AI techniques can be applied successfully in the identification and monitoring of severe accident scenarios in real PWRs.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.946-956
• /
• 2008

Acoustic emission(AE) is low-energy seismic event associated with a sudden inelastic deformation such as the sudden movement of existing fractures, the generation of new fractures or the propagation of fractures. These events rapidly increase before major failure and happen within a given rock volume and radiate detectable seismic waves. Rock slopes are usually large in scale and there are many discontinuities in rock mass. AE waves are strongly attenuated when they propagate through joints. Thus we should resolve the attenuation problem to monitor large volume. In this study, we developed waveguide which is composed of two different materials, cement mortar and stainless steel rod. And several laboratory tests on developed waveguide are performed to obtain generalized AE parameters to predict the failure stage in rock slope. Comparing field data with experimental data in laboratory tests, failure stage of rock slope can be evaluated. To verify and optimize the developed monitoring method, we are now carrying out the field application at a rock slope.

• International Journal of Contents
• /
• v.16 no.1
• /
• pp.75-86
• /
• 2020

As the elderly population is becoming an aging society, the elderly are experiencing many problems. Social security costs for the elderly are increasing and the un-linked social phenomenon is emerging. Thus, the social infrastructure and welfare system established in the past economic growth period are in danger of not functioning properly. People socially isolated or with chronic diseases among the elderly are exposed to various accidents. Thus, an active healthcare management service is imperative. Additionally, in the event of a dangerous situation, the system must have ways to notify guardians (family or medical personnel) regarding appropriate action. Thus, in this paper, we propose the smartphone-based healthcare and emergency response service platform. The proposed service platform aggregates movement of relevant data in real-time using a smartphone. Based on aggregated data, it will always recognize the user's movements and current state using the human motion recognition mechanism. Thus, the proposed service platform provides real-time status monitoring, activity reports, a health calendar, location-based hospital information, emergency situation detection, and cloud messaging server-based efficient notification to several subscribers such as family, guardians, and medical personnel. Through this service, users or guardians can augment the level of care for the elderly through the reports. Also, if an emergency situation is detected, the system immediately informs guardians so as to minimize the risk through immediate response.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.833-835
• /
• 2010

The SPARTAN-3E development kit is equipped with an FPGA which holds 500 thousand logic gates and a bus system platform using MicroBlaze microprocessor system. This kind of embedded systems can be used to gather information from sensor nodes and send over to the main server periodically through the network gateway, using the microprocessor-based embedded system, so that edlers living alone under sensor coverage can send their moving information and can be applied to get help in the event of emergency situations. In this paper, we designed a simple embedded system based on a CPU and flash memories using such FPGAs which can be used to monitor those elderlies living alone. The developed hardware system can be directly combined with the web-based elders-living-alone monitoring system, making the system more efficient.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.3153-3158
• /
• 2014

Children in schoolzone accidents occur frequently in order to actively respond to the situation on the module for automated recognition research. By the vehicle penetration such like schoolzone, child object recognition, and GPS coordination information, the monitoring scenario can be constructed, and if an event occurs corresponding to strategic scenario so that suitable reaction can be provided to increase safety level to the schoolzone. In this paper, a GPS sensor and the image sensor and the monitoring server on the network based on the integration of context-aware methods have been studied. The image sensor section and the GPS section through analysis of the situation analysis and recognition of the object based on the scenario can actively cope with the situation according to the methods proposed.

• Nuclear Engineering and Technology
• /
• v.53 no.6
• /
• pp.1858-1868
• /
• 2021

Resisting an accidental impact of large commercial aircrafts is an important aspect of advanced nuclear power plant (NPP) design. Especially after the 9·11 event, some regulations were enacted, which required the design of NPPs should consider the accidental impact of large commercial aircrafts. Normal working of equipment is important for stopping reactor under an impact when an NPP is in operation. However, there is a lack of reliable analysis and research on the impact test of nuclear prototype equipment. Therefore, in order to study the response of the equipment under high acceleration impact, a centrifugal pump is selected as the research object to perform the impact test. A horizontal half-sinusoidal pulse wave was applied to the working pump. The test results show that the horizontal response of the motor and flange is greater compared to other parts, as well as the vertical response of the coupling. The stress response of the pump body support and motor support is high, hence these parts should be considered in the design of the pump. Finally, combined with the damage and stress evaluation results of the pump under different amplitudes, the ultimate impact acceleration that the pump can withstand is given.