• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.215-221
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• 1976

In this study, noise arresting effect of the noise control room from the transmission of surrounding noise was tested when the packing noise control rooms were set up in the test room in which the prerecorded noise from an engine room was reradiated at the same level as the original pressure. The inner space of control room A is $3.389m^3(1.19\times1.19\times2.14m)$ having walls furnished with plywood board 9mm in thickness and noise control room door$(60\times45cm) $ and illumination lamp are placed. In case of the control room B, noise absorption board(10mm fiber board which holds the corntype concavity with diameter of 5mm, depth 5mm, space 15mm) is adhered to the internal ceiling and styrol foam boards(20mm) to the walls. The other struction is same as the control room A. Type C is the same as B except wool board(Glass Fiber, 33mm) on the walls. Type D is same as type A except that the thickness of wall is 12mm and wood pyramid type cone$(5\times5\times13cm)$ is adhered to the ceiling ana walls(Fig. 1). When the recorded noise and vibrated noise were controlled in various levels. The noise pressure which passed through the control rooms was measured by sound level meter(Bruel & Kjar 2205, measuring range 37-140dB). In order to calculate the absorption rate in the control rooms the noise pressure was measured at different distances when the recorded noise pressure was radiated. The followings are the results obtained from the experiment. 1. When the noise pressure of the test room was 60dB, transmission rate of type A was $69.7\%$ and increased $3.3\%$ per 10dB. At the same condition, the rate was $53.9\%$ and increased $4.5\%$ per 10dB in type D. Type D was the most effective in noise arresting of the four and the effect was D,C,B and A in order(Fig.2). 2. When the oscillator sound and vessels noise were radiated in 1,000Hz, at one meter distance to the type A and D, the oscillator sound pressure were 77dB and 73dB, while the vessels noise pressure were 73.3dB and 66.2dB respectivley(Fig.3). 3. Refering to the influence of the frequency to the lower oscillator sound(1,000Hz) pressure, both type C and D were almost same at 140cm but type C was 0.3dB lower than type D at 20cm distance(Fig.4).

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.4
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• pp.347-370
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• 2011

Slurry type shield would be very effective for the tunnelling in a sandy ground, when the slurry pressure would be properly adjusted. Low slurry pressure could cause a tunnel face failure or a ground settlement in front of the tunnel face. Thus, the stability of tunnel face could be maintained by applying an excess slurry pressure that is larger than the active earth pressure. However, the slurry pressure should increase properly because an excessively high slurry pressure could cause the slurry flow out or the passive failure of the frontal ground. It is possible to apply the high slurry pressure without passive failure if a horizontal impermeable layer is located in the ground in front of the tunnel face, but its location, size, and effects are not clearly known yet. In this research, two-dimensional model tests were carried out in order to find out the effect of a horizontal impermeable layer for the slurry shield tunnelling in a saturated sandy ground. In tests slurry pressure was increased until the slurry flowed out of the ground surface or the ground fails. Location and dimension of the impermeable layer were varied. As results, the maximum and the excess slurry pressure in sandy ground were linearly proportional to the cover depth. Larger slurry pressure could be applied to increase the stability of the tunnel face when the impermeable layer was located in the ground above the crown in front of the tunnel face. The most effective length of the impermeable grouting layer was 1.0 ~ 1.5D, and the location was 1.0D above the crown level. The safety factor could be suggested as the ratio of the maximum slurry pressure to the active earth pressure at the tunnel face. It could also be suggested that the slurry pressure in the magnitude of 3.5 ~4.0 times larger than the active earth pressure at the initial tunnel face could be applied if the impermeable layer was constructed at the optimal location.

• Journal of the Korean Society of Earth Science Education
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• v.17 no.2
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• pp.86-101
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• 2024

The purpose of this study is to provide basic data on the importance of accurate scientific communication and the current status of popular astronomy based on science articles that occurred during the so-called Super Blue Moon astronomical phenomenon in August 2023. To this end, the subjects were divided into non-experts, quasi-experts, and experts based on the degree of knowledge of the astronomical universe to investigate the data interpretation ability of astronomical science information and to analyze the causes of errors in the interpretation process through in-depth interviews. We also investigated the favorability and reliability of research institutes that strive to provide scientific information and the media that strive to spread it and also investigated the changes in existing favorability and reliability when incorrect scientific information spreads, as in this case. Although there were differences in the interpretation of scientific information about the astronomical universe depending on the cognitive aspect, the influence of linguistic elements or literacy, which could be called communication, could not be ignored. In particular, it was confirmed that misconceptions inherent in the existing research subjects could be expressed, leading to errors in accurate information interpretation. In addition, after recognizing that errors were included in the spread of scientific information, the subjects' favorability toward research institutes and the media fell 12.30% and 17.58%, respectively, while reliability fell 19.40% for research institutes and 24.49% for media outlets. Regardless of the cause of the error, the importance of providing accurate scientific information is further emphasized, considering that the overall favorability and reliability of both research institutes and the media decline. In order for research institutes and media outlets to spread accurate scientific information about the astronomical universe based on the public's trust, it is necessary to establish a system that can accurately deliver error-free information generated by research institutes related to astronomical space to media or science communicators and to develop a system that quickly retrieves and corrects incorrect scientific information through continuous monitoring.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.118-129
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• 2011

This Study has developed the information system of the rivers based on 3D image GIS by converging the latest information technology of GIS(Geographic Information System), RS(Remote Sensing), GNSS(Global Navigation Satellite System), aerial laser survey(LiDAR) with real time network technology in order to understand the current situation of all the four major rivers and support the administrative management system. The said information system acquires the high resolution aerial photographs of 25cm, aerial laser survey and water depth surveying data to express precise space information on the whole Youngsan River which is the leading project site out of the four river sites. Monitoring the site is made available on the transporting means such as a helicopter, boat or a bus in connection with locational coordinate tracking skill for the moving objects in real time using GNSS. It makes monitoring all the information on the four river job sites available at a glance, which can obtain the reliability of the people to such vast areas along with enhancing the recognition of the people by publicity of four Rivers Revitalizing Project and reports thereof.

• Journal of KIISE:Software and Applications
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• v.36 no.6
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• pp.471-478
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• 2009

Recently, researches for user interface are remarkably processed due to the explosive growth of 3-dimensional contents and applications, and the spread class of computer user. This paper proposes a novel method to manipulate windows efficiently using only the intuitive motion of hand. Previous methods have some drawbacks such as burden of expensive device, high complexity of gesture recognition, assistance of additional information using marker, and so on. To improve the defects, we propose a novel visual touchless interface. First, we detect hand region using hue channel in HSV color space to control window using hand. The distance transform method is applied to detect centroid of hand and curvature of hand contour is used to determine position of fingertips. Finally, by using the hand motion information, we recognize hand gesture as one of predefined seven motions. Recognized hand gesture is to be a command to control window. In the proposed method, user can manipulate windows with sense of depth in the real environment because the method adopts stereo camera. Intuitive manipulation is also available because the proposed method supports visual touch for the virtual object, which user want to manipulate, only using simple motions of hand. Finally, the efficiency of the proposed method is verified via an application based on our proposed interface.

• Tunnel and Underground Space
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• v.13 no.3
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• pp.187-195
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• 2003

This case study which is to make 2-Dimension earth's crust structures clearly is about the great boring-hole blasting to provide ground vibration source of the reflected wave research on the Korean Peninsula earth's crust structures research. For this study we've done blasting twice-500 ㎏/charge per delay, 1,000 ㎏/charge per delay, and the specifications of blasting are the following - dia.: 300 ㎜, boring-depth : 100m, besides, we used the explosives and electric detonators which have sufficient detonating velocity and very excellent safety, capacity of detonating, accurate delay time. We charged explosives into steel pipe with bulk type to avoid dead pressure by ground water. And then we tested about pipe airtight and blasting to certificate which has no problem by using on this study. In the results, we succeeded each blasting in Seosan, Youngdong. For the Peak Sum Vector(PSV) around the blasting at the main points, its real measured PSV is higher 180 % than estimated PSV with USBM. In this study we can't to be analysis of vibration velocity, but to be key providing vibration source.

• Journal of Environmental Impact Assessment
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• v.23 no.6
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• pp.417-431
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• 2014

There is a Conjoint Analysis to estimate the environmental value of natural river restoration project of Inchon Metropolitan City's small River: Gong-chon Stream, Gul-po Stream, Seung-gi Stream, Jang-su Stream. In order to find out the optimal expense condition, we tried to estimate the possible payable amount. According to the analysis, almost all people are willing to pay 15,000 Won. In case of the river types, the people liked 10 cm's depth of water and there should be brook trail, convenient facilities and flood plain at the stream edge space. But it is impossible to build these facilities with minimum fare 15,000 Won per a household. If the necessary expenses set high, the tax resistance of the local residents will be increased. So, in consideration of the analytical results of the attribute level, we draw five alternatives. This study is based on the results of Incheon metropolitan City residents' survey, and there is Conjoint Analysis to estimate the environmental value of natural-type river project of Incheon metropolitan City. If it is reflected the special assume factors of this study, and if there is exact environmental value estimation of the various river quality through different analysis, then it will become a study of high utilizing.

• Journal of Digital Convergence
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• v.18 no.11
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• pp.177-185
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• 2020

The spread of COVID-19 has caused confusion in the education field as it has led to the implementation of untact classes without preparation. The purpose of study is to find ways to effectively design and operate untact classes for tax accounting department. The survey and FGI were conducted on professors and learners. As a result, video classes through lecture shooting and PPT-based video conversion were the most utilized. Students prefer these two types most, because they can learn repeatedly regardless of time and space. The improvement measures are as follows. For video classes that reflect various characteristics of the subject, supporting for equipment and human resources is needed, and for professors, teaching support for untact classes and education on equipment manipulation is needed. Continuous Quality Improvement for untact classes should be overhauled. In the future, in-depth research is needed to various majors, this will help find ways of untact classes suitable for the characteristics of the subjects.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.102-109
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• 2014

A particle system is used for modeling the physical phenomenon. There are many traditional ways for simulation modeling which can be well suited for application including the landscapes of branches, clouds, waves, fog, rain, snow and fireworks in the three-dimensional space. In this paper, we present a new fireworks modeling technique for modeling 3D firework based on Firework Particle Tracking (FPT) using the particle system. Our method can track and recognize the launched and exploded particle of fireworks, and extracts relatively accurate 3D positions of the particles using 3D depth values. It can realize 3D simulation by using tracking information such as position, speed, color and life time of the firework particle. We exploit Region of Interest (ROI) for fast particle extraction and the prevention of false particle extraction caused by noise. Moreover, Kalman filter is used to enhance the robustness in launch step. We propose a new fireworks particle tracking method for the efficient tracking of particles by considering maximum moving range and moving direction of particles, and shall show that the 3D speeds of particles can be obtained by finding the rotation angles of fireworks. Also, we carry out the performance evaluation of particle tracking: tracking speed and accuracy for tracking, classification, rotation angle respectively with respect to four types of fireworks: sphere, circle, chrysanthemum and heart.

• Korean Journal of Social Welfare
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• v.68 no.1
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• pp.23-52
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• 2016

This study aims to reveal the meaning and essence of male immigrant workers' life who underwent industrial accidents through specific experiences. This study is based on the Van Manen(1990)'s lived experience phenomenological method, which actively describes the experiences about the industrial accidents in the perspective of male immigrant worker. The in-depth interviews were carried out with the thirteen male immigrant workers participants who underwent the industrial accidents. Through the interview, 121 meaning units and 38 disclosed themes were constructed. The following is the summarized results as 9 essential themes: < the oppression of the Industrial accident compensation insurance's hospitals to the aliens >, < being treated like the surplus man who lost the labor force >, < the class rank below despite undergoing the industrial accidents >, < survival having resistance sentiments >, < living at the anonymous lands as the Homo sacer >, < the stratified strategies between the immigrant workers >, < the origins as the bodiless shadow >, < struggling to escape the present conditions >, < present circumstances tied by the past experiences without hope >, researcher sought the essential meaning structure about the four Life-world Existentials (Body, The other, Space and Time) of constructing human's live-world. Based on the study results, some suggestions were made to restore the male immigrant workers' damaged quality of their lives who experienced industrial accidents and to contribute the social integration in view of the social welfare.