• Journal of agricultural medicine and community health
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• v.34 no.2
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• pp.202-213
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• 2009

Objectives: The aim of this study was to compare health related behaviors among adolescents in the rural area with those in the urban area in Korea. Methods: The data source was the Korea Youth Risk Behavior Web-based Survey in 2005. With two stage cluster sampling, a total of 58,224 sample was selected from 799 middle and high schools nationwide. The area was classified into county area, small to medium city, and large city, and then the county area was considered as a rural area. Data was analyzed with STATA 9.0 using the method of complex survey data analysis considering sampling weight, strata, and primary sampling unit. Results: The prevalence of health related behaviors among adolescents in the rural area was higher than the city area as following health behaviors: smoking behaviors of smoking experience, smoking experience before entrance to middle school; drinking behaviors of frequent drinking, high risk behaviors with drinking; dietary behaviors of omitting of lunch or dinner, less intake of fruits or milk, more intake of cooky; oral hygiene of less tooth brushing, less preventive oral care, more oral symptoms and less dentist visit; safety behaviors of less wearing of safety belt or protective device; general hygiene of less hand washing before meal or after visiting rest room. Conclusions: The health behaviors among adolescents in the rural area were generally poorer than the city area. The results showed national health program for adolescents should be conducted primarily for those in rural areas. Further study is needed to explore the factors related with the discrepancy of health behaviors between the rural and urban area.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.247-255
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• 2023

The occurrence of sudden strike pest events in urban areas is increasing as global warming intensifies, consequently, re causing harmful impacts. Studies on these incidents are fewer in number and insufficient compared to research on other nuisances such as mosquitoes and flies. Therefore, we conducted a study on the development of a selective collection method, using a filter layer to establish a monitoring system for Ephemera orientalis (Ephemeroptera: Ephemeridae), a species frequently identified as a sudden strike pest. Three sampling points were selected along the Hangang River in Namyangju, where E. orientalis outbreaks occur. Prototypes, consisting of four layers and with a light source attached to attract insects, were installed at each sampling point. Sampling was performed every 30 minutes between 19:00 and 22:30 in the month of June. The filter interval of each layer was adjusted so that the collected mayflies were distributed into specific layers. To evaluate the collection efficiency in line with the materials and the filter intervals, the optimal collection efficiency was investigated by combining two types of layer materials (stainless and acrylic) and filter intervals (1-5 mm). The optimal conditions were as follows: The selective collection efficiency was found to be highest at 96.5% when the interval of the selective target filter was 2.0 mm and there was one upper filter.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.613-618
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• 2011

More than 7 million persons use Seoul Metropolitan Subways (SMS) everyday and the number has been in increasing trend. With the increasing trend of concerns on indoor air quality(IAQ), the management of IAQ has become an important issue, especially in case of subway operators, because most of subway lines are placed underground with poor ventilation condition. The ultimate object of study develop independent cleaning device that reduce efficient fine particle and $CO_2$. Urban subway has characteristics about proper clean air flow, must be installed in narrow space and maintenance cycle has enough time. Two layered electrically pre-charged filters were used for removing particulate matters and gas absorbers are packed between two layer filters for removing gases pollutants such $CO_2$, VOCs and HCHO. Urban subway has characteristics about proper clean air flow, must be installed in narrow space and maintenance cycle has enough time. SCAP prototype is producted as all in one method which decrease fine dust, $CO_2$ and noxious gas. and basic test carry out with quantity of wind, a gap of pressure, sampling efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.12
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• pp.1871-1876
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• 2004

We demonstrate a novel fabrication technology for the microneedle array that can be used in the medical test field, which is transdermal drug delivery and blood analyte sampling. Previous researchers have used silicon-processed micromachining, a reactive ion etching, and molding techniques for the fabrication of microneedle array. However, these fabrication techniques have somewhat limitations apply to the microneedle array fabrication according to its application. Inclined LIGA process is suggested to overcome these problems. This process provides easier, sharper and longer out-of-plane microneedle array structure than conventional silicon-processed fabrication method did. Additionally, because of the advantage of the LIGA process based on mold fabrication for mass production, the polymer, PMMA(PolyMethylMethAcrylate), based microneedle array is useful as the mold base of nickel electroplating process; on the other hand, silicon-processed microneedle array is used in itself. In this research, we fabricate different types of out-of-plane microneedle array, which have different shape of tip, base and hole structure, using the inclined LIGA process. The fabricated microneedles have proper mechanical strength, height and sharpness to puncture human hand epidermis or dermis with less pain and without needle tip break during penetrating the skin.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.149-151
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• 2006

This Study has the influence on the viewing determinative factors of pro-soccer sporting events base on viewing satisfaction. To attain the goal of the study described above paragraphs, some viewers of '06 season pro-soccer games held in Daejeon province was set as a collected group. Then, using the stratified cluster random sampling method, finally drew out and analyzed 388 people. The material collection device was the brochure named . To analyze materials, the regression analysis techniques. The conclusion based on above study method and the result of material analysis are here below. The pro-soccer sporting events viewing determinative factors influence on viewing satisfaction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.349-358
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• 2004

A low pressure impactor is an impaction device to separate airborne particles into aerodynamic size classes at low pressure condition. We designed a two-stage low-pressure impactor to classify submicron sized environmental aerosols. Performance evaluation was carried out for stages 1 and 2 by using an electrical method. Monodisperse liquid dioctyl sebacate (DOS) particles were generated using evaporation-condensation process followed by electrostatic classification using a DMA (differential mobility analyzer). The test particles were in the range of 0.08∼0.8$\mu\textrm{m}$. For the evaluation of the impactor we used two electrometers; one was connected to the impaction plate of the impactor and the other was to the Faraday cage used as a backup filter. The effect of polydispersity of test aerosols on the performance was investigated. The results showed that the experimental 50-% cutoff diameters at each impactor's operation pressure were 0.53 and 0.187$\mu\textrm{m}$ for stages 1 and stage 2, respectively. The effects of operation pressure on the cutoff diameter and the steepness of collection efficiency curves were also investigated.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.119-128
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• 2008

Laboratory analytical results of 22 sets of hydrophobic adsorbent coils containing surface soil-vapor and two soil samples collected by conventional intrusive method from each boring location at two active dry cleaning facilities in the State of Illinois, U.S.A, were presented to evaluate the performance of soil-vapor survey. The most critical factor to determine the effectiveness of soil-vapor survey is the distance from the soil-vapor sampling device to the actual contamination, which is a function of soil porosity, permeability, primary lithology, and other geological and hydrogeological site-specific parameters. Also this factor can be affected by the history of contaminant-generating operations. The laboratory analytical results in this study showed longer dry cleaning operation history (i.e., 50 years) and presence of fine sand at the beneath Site B allow the contaminants to migrate farther and deeper over a fixed time compared to Site A(i.e., 35 years and silty clay) so that the soil-vapor survey is not likely the most effective environmental site investigation method alone for Site B. However, for Site A, the soil-vapor survey successfully screened the site to identify the location reporting the highest soil concentration of chlorinated solvents.

• Journal of Mechanical Science and Technology
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• v.14 no.9
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• pp.956-967
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• 2000

In this paper, we explore the issues of force display in the cooperative virtual environment shared by multiple users distributed over the network with heterogeneous hardware platforms. The proposed method is to cope with the problem of small time delay and the difference of sampling rate in the distributed configuration. In the proposed approach the interaction forces of the participants are just treated as the independent sources of acceleration. Thus the action of a participant simply changes the acceleration of the virtual object and consequently the states of the virtual object will be updated. When the updated states are reported to all the participants, the information on the time of state changes is delivered, too. Employing the discrete state information updated by the other users, each user modifies his own virtual environment and pseudo-realtime simulation can be realized. Excluding the software interface and the communication technique, it is proposed the simulation method for the operation of respective users and the way of calculating the driving input to the display device. For experimental verification we construct a cooperative virtual environment shared by two remote users and outline the results of experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.515-518
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• 2006

A vibration test for a cylindrical rod inserted on the grid support structure was tested using the sine sweep excitation method with closed loop force control. The effect of the mounting location of a test rod on the vibration characteristics of a rod continuously supported by the full size($16{\times}16$) grid support was identified. An electromagnetic vibration shaker, non-contact displacement sensor and HP/VXI data acquisition device were used and TDAS software was also used as a data sampling and processing tools. The natural frequencies and mode shape of the test rod were consistent with the previous works of a rod vibration test with partial grids($3{\times}3,\;5{\times}5\;and\;7{\times}7$). The frequency characteristics of the rod according to the mounting location were shown clear discrepancies, but mode shapes were nearly same. As the test rod closes to the bottom clamping region of the spacer grid, peak vibration amplitudes of the rod become smaller.

• Journal of Ocean Engineering and Technology
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• v.34 no.3
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• pp.202-207
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• 2020

A track-type underwater construction robot (URI-R) was developed by the Korea Institute of Ocean Science & Technology. Because URI-R uses tracks to move on the seabed, insufficient ground strength may hinder its movement. For smooth operation of URI-R on the seabed, it is important to determine the geotechnical properties of the seabed. To determine these properties, standard penetration test (SPT), cone penetration test (CPT), and sampling are used on land. However, these tests cannot be applied on the seabed due to a high cost owing to the vessel, crane, sampler, and analysis time. To overcome these problems, a free fall cone penetration tester (FFCPT) is being developed. The FFCPT is a device that acquires the geotechnical properties during impact/penetration/finish phases by free fall in water. Depth information is crucial during soil data acquisition. As the FFCPT cannot measure the penetration depth directly, it is estimated indirectly using acceleration. The estimated penetration depth was verified by results of real tests conducted on land.