• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.243-250
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• 2009

The expression of signal to noise ratio (SNR) is derived for the individual echo sounder and for the general specifications of commercial echo sounder. The SNR is depicted by several factors on transmitting and receiving, sound propagation, scattering by fishes, and mainly self ship noise. The detection ranges of echo sounders in depth and breadth are derived by finding the border of an acceptable SNR. The detection ranges are computed for the echo sounders of individual and general specifications. Generally, the detection range is lager for low frequencies. Increasing an electrical power and a diameter of transducer is not as effective for high frequencies as for low frequencies to increase the detection range. The theoretical results of the detection range can be applied to design low electrical power echo sounder for coastal use, to select an appropriate echo sounder, to know the capability of a sounder, and to interpret echograms. A method for evaluating and designing low electrical power echo sounder is developed. A universal diagram for the basic design of the low electrical power echo sounder where SNR is plotted against frequency is developed. An appropriate frequency, transducer diameter, and beam width are easily determined by using the diagram.

• Archives of design research
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• v.17 no.2
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• pp.15-22
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• 2004

Recent complex visual culture is the visual world widely magnified according to the images like image, graphics, photograph, movie, and television, etc. by the development of digital technology. Because it conveys meanings and contents inserting sound and letters, it may have multimedia character conveying and communicating information beyond general language and letters. The vision for various images at that time is inseparably connected with language. And imaginative order of image and vision are composed of special way in culture and history. Language is different in society, culture, and history. Accordingly, if visual experience is communicated with language partially, it is difficult to have university. So, role of linguistic order plays an important role in forming and defining the social and cultural differences among the visual systems. Historically various visual and optical devices with this visual language have influenced a lot. These visual technologies are concrete and physical practice determining a way to get together with the subject and the visible object in the visible world. The visual language is connected with dimension like these symbols of images and the dimension like visual technologies to series of historical physical and institutional practices. It determines social visual mode toward object world in one of visual system. Accordingly, this study is to understand visual language with social and historical character according to the changed concept and characters as development of media technology. And it is to explain it in view of visual language as a dimension of symbol and visual technology of institutional and physical practice. After all, it cannot explain the effect on the function and visual mode of visual technology as its technical element only. It also cannot separate with the practice with coherent discourse and the physical and institutional practice. The possibility, technical element of technology contains, does not realize as it is but the effect is always communicated in the social veins and realized with a restriction.

• Tunnel and Underground Space
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• v.11 no.4
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• pp.319-327
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• 2001

Introduction of new design tools has been required to optimally design and operate the ventilation system of long vehicle tunnels.. The demand has led to wide spread use of the simulation technique throughout the would to analysis the dynamic relationship among the variables associated with vehicle tunnel ventilation. This paper aims at performing on-site study at local tunnels to test the applicability of NETVEN, a simulation model vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels model of vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels employing different ventilation systems as well as traffic methods. There were some discrepancies sound between the simulation output and measurements and the following four factors are considered to mainly cause those disagreement. (1) The real situation shows distinctive transient and retarding characteristics with respect to air flow and contaminant dispersion, while ventilation forces are not steady-state and in particular those traffic and climatic variables show significant instantaneous variation. (3) Near the exit portal, the CO levels show bigger differences. The general trend is that data with higher CO concentrations carry bigger discrepancies. Turbulent diffusion is though to be the main reason for it and also contribute to the fact hat the highest CO concentrations are found at the locations somewhat inward, not at the exit portals. (4) Higher traffic rate results in higher discrepancies of ventilation velocity. Along with the exhaust characteristics, the vehicle aerodynamic characteristics need to be studied continuously in order to reduce the velocity disagreement.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.2
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• pp.59-71
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• 2006

Due to the rapid process of industrialization the cities of Korea confront changes of climate, destructions of the habitate and decrease of the green. Recently Seoul and other local governments have implemented policies and projects to improve the environmental surroundings. In reality, however, those policies and projects face difficulties in the course of implementation. The fact that there are no concrete regulations and specific legal procedures turns out to be one of the main difficulties. The aim of this study is to present specific plans and methods of wall-planting and to provide basic guidelines for the future direction of wall-planting and offer ideas of facilitating wall-planting. This study is based on questionnaires from specialists of landscape architecture through individual interviews and/or e-mails. The questionnaire is consisted of following 4 sections. 1. Show the experts current regulations and/or legal procedures and ask them improvements and suggestions. 2. Ask them choose matters of the highest priority by using Ricardo's diagram method. 3. Ask them to make a graded list in terms of the location and method of wall-planting. 4. Study the maketability of the wall-planting products currently in circulation. The city of Seoul and the Ministry of Environment recommend that trellis and/or planting inducement structures be installed on the building wall by regulation. The specialists responded to the questionnaire advocate that green wall without trellis should be allowed as green zone. Therefore regulations concerning the wall-planting should be determined specifically according to the characteristics of individual plants and walls. It has been urged that legal aid and social support must be reinforced to establish rules dealing with wall-planting. The respondents also point out that significant cutting down of the tax is far more effective in accelerating the wall-green instead of administrative support. The highest priority in terms of planting has been given to sound-proof wall, retaining wall and building wall. Concerning the maketability of the wall-planting products, panel products are recommended for early-planting and building planting. It has been suggested that the research and study of new materials and species be done in advance.

• Archives of design research
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• v.18 no.1 s.59
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• pp.233-244
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• 2005

Fashion is one of the characteristics which represents the comtemporary sociocultural signifiant. A style that a certain stream of fashion brings is not just limited in fragmentary tendencies and fads. That can be a code to communicate and function as a medium in itself. Music has been displaying it's power to fashion while fashion has been exercising it's influence over the music. There is an inseparable relationship between music and fashion in terms of expressing our images of the world: fashion delivers them through visuality and music does it by sound. Both fashion and music are reflecting our society as well as they are influencing on sociocultural aspects generally. Whenever music has been changed new youth culture has been made and this culture has been expanded with forming some distinct fashion trends. The study focuses on identifying the relations between pop music and fashion styles which are occupying positions firmly on the bases of youth culture through analysing the relations between the fashion styles and music genres which are used in sub-culture groups to express their own identities and consciousness from a point of semiotics. In conclusion, subculture is the exit of their escaping from the compelling inconsistency cause by the condition of people's life and the way for them to solve through cultural sublimating for themselves. People come up with distinctive style of music and fashion to express their resistant signifie in their symbolic way. In addition, a particular music trend has much to do with a contemporary fashion style. In the relationship between music and fashion, there have been the subtle mechanism to boost and influence and some crucial similarity each other to signify inner values of the times. This study lets us realize that fashion is not only a popular style of clothes, hair, etc. at a particular time or place but also a medium to communicate and to guarantee polysemous identity by functioning as a flexible tool to exchange contemporary sociocultural meanings.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.641-657
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• 1998

This study was undertaken to compare the bond strength and the fracture site of new and recycled brackets according to the base design. 252 sound premolars extracted for orthodontic treatment were collected and Type I, Type II, Type III brackets were divided into four groups by recycling method Each bracket was then bonded to an extracted premolar. Instron Universal Testing Machine(model W) was used to measure the shear bond strength, and the surface of the recycled brackets were viewed in SEM For the analysis of the results, one way ANOVA and Scheffe's multiple range test was executed using the SPSSWIN program. 1. The shear bond strength showed statistically significant difference according to the bracket base design(p<0.001). Type III bracket(round indentation base, micro-etched) showed the highest bond strength, Type I bracket(foil-mesh base) was second, and Type II bracket(grooved integral base, micro-etched) was last. 2. The effect of recycling on the bond strength was different according to bracket type. The shear bond strength of Type I, Type II brackets showed the smallist reduction when treated for 1 minute in Big Jane(p<0.05), but the shear bond strength of Type III brackets showed no statistically significant difference according to recycling method(p>0.05). 3. In Type I, Type II brackets, frequent fracture site was bracket-resin interface, but in Type III brackets, about half of the resin was retained on the tooth surface frequently. 4. The shear bond strength was highest when about half of the resin was retained on the tooth surface(p<0.05). 5. The resin remnant on the bracket base after recycling had no effect on the shear bond strength.

• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.17-24
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• 2007

The noise problem is one of the major problems associated with large cities and is considered important factor not only in maintenance but also in development of cities. Accordingly, the noise map is being increasingly used in city planning and design. However, the existing two-dimensional noise maps only show regional, planar distribution of noise. This study presented a method to build a data model for analyzing and visualizing noise levels at fine scale considering the vertical distribution of noise in a building. By expanding the 2D topology concept used in conventional GIS to 3D, it suggested a 3D GIS data model that makes 3D spatial queries, analyses and visualization possible and applied the proposed approach to building a 3D noise information system. By building and testing the system, the study showed different functionalities including 3D spatial queries and 3D visualization of noise levels varying temporally or according as the height of sound-proof walls. In each case, the population exposed to noise was quantitatively computed to illustrate the potential in the areas of city planning and design.

• Archives of design research
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• v.14 no.2
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• pp.187-196
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• 2001

Today's internet advertisement market is growing rapidly placing great importance on banner advertisements. Still, banner advertisements are being ignored by the users because most of these banners are exaggerated, visually distracted and they usually interfere with internet surfing. These banners make the agents and the users feel displeased and furthermore, make internet market unstable. 'Rich-Media'came in sight as the new way of advertising means in the internet market as the users demand for more dynamic and interactive media. In Rich-Media, sound and animation interact with former animated banner advertisements. Internet advertising businesses inducing web agencies have positive views about Rich-Media, because more information and ideas are shared through aural and visual integration and it is very effective way to draw attentions from the users. In this study, we have examined the effects of Rich-Media advertisements through surveys. As a result, Rich-Media advertisements are superior to ordinary banner advertisements in visual effect, leading interests of users, inducing mouse did(s and providing of information. The recent uses of Rich-Media is just a mere beginning, but we expect to make the Rich-Media an essential medium of internet advertisement as we continue studying the uses and effects of Rich-Media.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.249-255
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• 2004

To investigate the return flow ratio of irrigation water, lots of observations were made during the irrigation periods in 2003 crop year. This Area is a portion of Dae-Am pumping station basin which is located in Changryung-gun, Gyeongnam province. A water balance analysis was performed for a paddy field in Dae-Am pumping station in the Nakdong river basin, which is constructed for irrigation water supply. Daily rainfall data in the this area were collected and irrigation water flow rate, drainage water flow rate, infiltration and evaportranspiration were measured in field area. Irrigation water flow rate and drainage water flow rate were continuously observed by water level logger(GTDL-L10) during the growing season. The infiltration and evaportranspiration were measured by cylindrical 300mm depletion meter and cylindrical 200mm infiltrometer, respectively. Total irrigation and drainage flows were 654.7mm and 281.2mm in 2003. Total infiltration and evaportranspiration were 36.0mm and 160.0mm respectively. The mean of the daily evaportranspiration rate was 4.3mmm/d. The prompt return flow and retard return flow ratio were 43.0％ and 5.5％, respectively. Total return flow ratio was 48.5％. Therefore, it can be concluded that the amount of irrigation water was much higher than design standard or reference in this study. It means that this was caused by the inadequate water management practice in the area where water was oversupplied on farmers' request rather than following sound water management principles, and design standard should be changed in the future.

• Journal of Korean Association for Spatial Structures
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• v.7 no.2 s.24
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• pp.105-114
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• 2007

Large span spaces have been widely used for various purposes including sports events in other countries. Due to increasing demands on multi-purpose use of such spaces, recently built large span sport facilities such dome stadiums have been required to accommodate sport events as well as performing events. Also, retractable ceilings and/or walls were generally adopted in those spaces for providing various event conditions. It seems obvious that the openings between diffuse fields and free field may cause difficulties in the acoustic design of such spaces In the present work, the acoustic characteristics of non-diffuse field has been investigated using 1/10 acoustic scale models. It was found that RTs at low- and mid-frequencies decayed faster than those at high-frequencies as the percentage of opening area increased. The decay rate of RTs at high frequencies were not influenced by increasing the area of an opening. Also high dependence of EDT on the percentage of opening area was observed at all frequency range. D50 was not improved by increasing the area of an opening up to 12.5% and then sharply increased. The application of Schroeder integration to evaluate the reverberation charateristics of coupled spaces may not be proper, since non-exponential decay process with double or triple decays of those spaces can not be properly defined. EDT seems more appropriate to predict reverberation at the early acoustic design stage of acoustically coupled spaces.