• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.154-161
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• 2009

Thanks to the circumstance of digital convergence, most of the world TV and radio stations are gearing up for digitalisation of broadcasting. In this flux, digital switchover in South Korea should be completed by 2012 when transmission of analogue broadcasting signal will be ceased. According to the report, it shows only over 30% take up roughly so far, but there is no official survey from relevant organisation. It is very comparable with British digital switchover which is same year as S. Korea and has been reported 88% take up as of 2008 Q2. Yet the digital switchover in S. Korea inferred from this current is not a rosy future and even seems to be perilous. The purpose of this paper is to predict the media future of S. Korea at the view point of futurology and draw out the possibilities which enable to affect viewing behavior. In order to analyse it applies the futures wheel which is one of useful tools for future work. Consequently it suggests a number of scenarios how to cope with the impending situation in S. Korea.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.147-154
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• 2009

Lately, superhigh speed network infra is developing with the fast speed, is evolved by step that existent appliances are digitalised and appliances are become remote control by being gear to network. Also, gearing in Home network and superhigh speed network infra, control appliances in Internet and research that do monitering is proceed. Therefore, describe about indoor environment automatic control system that use Wireless sensor and Microcontroler in this paper. Because using that electric power, Zigbee sensor and Wireless module, embodied system that measured in the room temperature and use ATmega128 Microcontroler and use each device (temperature, illumination, humidity) back in house and control humidifier, electric fan etc. Can use variously in Home network field by this Wireless sensor and Microcontroler base, and also can apply variously to several industry fields as well as Home network field.

• Journal of Korean society of Dental Hygiene
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• v.10 no.1
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• pp.51-64
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• 2010

Obiectives : The purpose of this study was to examine the oral health knowledge and practice of elementary school children in the upper grades in a WHO healthy city for the development of oral health education programs gearing toward improving oral health care habits and oral health. The subjects in this study were 379 sixth-grade children in an elementary school in a WHO healthy city, Changwon. Methods : The questionnaire used in the study covered general characteristics with five items, oral health knowledge with 35 items and oral health care practices with 24 items. The oral health knowledge category consisted of general oral health knowledge with 13 items, knowledge on oral hygiene management with 11 items, knowledge on fluoride use with 8 items and healthy diet knowledge with 3 items. The oral health care practice category consisted of general oral health care practice with six items, practice on oral hygiene management with 11 items, practice related to fluoride use with four items, and healthy diet practice with 3 items. Results : The surveyed school children got a mean of 46.1 and 40.8 on oral health knowledge and oral health care practices, respectively out of 100 points. In the knowledge category, they scored the lowest on healthy diet knowledge with 12.6, and in the practice category, they scores the lowest on the practices related to fluoride use with 21.4. According to the regression analysis, gender had a significant impact on their oral health knowledge. The boys lagged behind the girls in that regard. Their oral health care practices were under the significant influence of knowledge level. Conclusions : Systematic education programs should be provided to prevent dental caries and promote oral health of school children, and the type of programs that stress actual oral health care is especially important.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.70-80
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• 2001

A cycloid reducer is one of the rotational velocity reduction equipments of machinery. It has advantages of the higher reduction ratio, the higher accuracy, the easier adjustment of transmission ratio and the smaller workspace than other kinds of reducer. A cycloidal plate gear is a main part of the cycloid reducer. Its tooth shape is peculiar because of gearing with the roller gear that has the several rollers on the circular line. And then it can be designed to contact all teeth to rollers. So, the cycloid reducer has the good characteristics in the dynamic properties and the zero-backlash in the contact motion. It can be used in robots, high-precision machines and high capacity machinery. This paper proposes a new approach for the shape design of the cycloidal plate gear and presents a Computer-Aided-Design program developed by the proposed method. The first part of this paper defines the two types of the cycloid reducers and explains their mechanisms. The second part defines the instant velocity centers for each type of the cycloid reducers and calculates the contact angles and the contact points by using te geometric relationships and the kinematical properties of the reducers. The third part generates the full shape of the cycloidal plate gear by the coordinate transformation technique. Finally, this paper presents two examples for the shape design of the cycloidal plate gear in order to prove the theory of the proposed method in this paper and the accuracy of the \"CycloGear Designer\".

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.131-136
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• 2004

The limited slip differential(LSD) is a device which enables the driving force to be transmitted from one slipping wheel to another wheel in such case that the car is stuck in clay or snow. When the unwanted slipping occurs on one wheel, the LSD temporarily restraints the differential motion to transmit the driving force in the other wheel. So far, many types of LSD were developed such as mechanical lock type, disk clutch type, viscous coupling type, torsion type and multiple clutch type. However these types of LSD is too complicated and expensive, so it is used only for 4WD outdoor vehicles, military vehicles, and a portion of deluxe car. So, many studies has been devoted to improve new types of LSD to cover those demerits of existing LSDs that the hydraulic LSD is developed as arepresentative result of that. The hydraulic LSD which uses the principle of gear pump is packed with viscous oil in tight container. When a slip occurs on one wheel, the hydraulic LSD generates torque caused by high oil pressure in the container. This study has been devoted to suggest an improved hydraulic LSD. In order to achieve it, we designed a new type of hydraulic LSD, produced it and did a rig test with it on real vehicle. From the rig test, it has been confirmed that the new type of hydraulic LSD can be directly applied to exiting vehicles without changing the design criteria

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.1
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• pp.83-90
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• 2012

The purpose of this study was to set and analyze the standard model for prioritizing and deciding to take part in housing environment improvement project in the perspective of the public sector. The results of this study were as follows. The location competitiveness, potential demand, marketability and competitive price, etc were selected by assessment indicators. And Various indicators, including of the size of the area, public transportation, accessibility, convenience of living and the influx of the population, were used by weights indexes. The profit of local residents and the public promoter, variability of earnings, sensitivity analysis and the ratio of money in reserve, etc were also established as detailed indexes for the profitability and business risk analysis. To analyze the cash flow of the project process and review the necessary capital in advance, the payback, total working expenses, gearing ratio and sensitivity of a risk, etc were also set as additional detailed indexes. Lastly, considering it is quasi-public projects, the measure to protect tenants, necessity need of redevelopment and local government's will were additionally used by indexes. And Points were distributed on the importance of each index and scored out of 100. It will allow for the public project promoter to decide rationally whether to come in on the project. The public project promoter like the Korea Land and Housing Corporation will be able to make use of various indexes are based on this study to make decision whether joining the housing environment improvement project in depressed region.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.4
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• pp.203-208
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• 2007

Ministry of Information and Communication is pushing for IT 839 strategy that has main points : 8 major service which can develop IT industry of Korea on the whole, 3 major infra, and 9 major new growth power. Of these, RFID/USN utilizing service is expected to exert a great influence the whole industry from field that is closely related with our life to national defense, supply, construction, transportation, physical distribution, manufacture, circulation, and service. In domestic case, departure of RFID/USN field is a little bit later than advanced nation's, and a technique difference between domestic field and that of advanced nation is about 2 years. In this situation, in order to develop middleware of various field gearing RFID Tag efficiently, we have to study about user interface and data analysis technique that is used in middleware commonly. This paper searches about WPF that appears in user interface field with up-to-date technique, and embodies 3 dimension visualization information system with WPF.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.442-445
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• 2005

It constructs a database generally and service it does, to use a commercial business DBMS that manages information and to use a retrieval system that supports a search, it adopts the gearing method of the DBMS and information retrieval system. But like this method is inconvenient must operate the DBMS and information retrieval system with duplication to be, there is a weak point where the data management and processing become accomplished with duplication. It presents the DB construction and information search and the management model of the KRISTAL-2002 information retrieval and management system base for the scientific and technical information data management and processing from the dissertation which it sees.

• Journal of Computational Design and Engineering
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• v.1 no.1
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• pp.27-36
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• 2014

Similar to the essential components of many mechanical systems, the geometrical properties of the teeth of spiral bevel gears greatly influence the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show a unique advantage in transmission due to their constant spiral angle property. However, a mathematical model suitable for accurate digital modeling, differential geometrical characteristics, and related contact analysis methods for tooth surfaces have not been deeply investigated, since such gears are not convenient in traditional cutting manufacturing in the gear industry. Accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed in this study, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry; actually, the tooth surface is a parametric surface defined on a parallelogrammic domain. Equivalence proof of the tooth surface geometry is then given in order to greatly simplify the mathematical model. As major factors affecting the lubrication, surface fatigue, contact stress, wear, and manufacturability of gear teeth, the differential geometrical characteristics of the tooth surface are summarized using classical fundamental forms. By using the geometrical properties mentioned, manufacturability (and its limitation in logarithmic spiral bevel gears) is analyzed using precision forging and multiaxis freeform milling, rather than classical cradle-type machine tool based milling or hobbing. Geometry and manufacturability analysis results show that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multiaxis freeform milling also need to be solved in a further study.

• Journal of the Korean Society for Precision Engineering
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• v.1 no.3
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• pp.85-94
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• 1984

The WILDHABER-NOVIKOV gear, one of the circular arc gears, has the large contact area between the convex and concave profiled mating teeth, moves from one end of the tooth to the other axially making a face contact. Hence it provides a large load capacity than the Involute gear and still satisfying the law of gearing. In order to analyze the gear stress, a photoelastic investigation was carried out. Photo elastic model of the WILDHABER-NOVIKOV gears were made of Araldite CT200 in this investigation. For both the many teeth gear and the few teeth gear segments, External gears of all addendum type WILDHABER-NOVIKOV gear and the involute gear were tested. Included were the models with various profile raddi at the same pressure angle 20 .deg. and module 13.5. The flank stresses and fillet stresses of these gears were observed in each case and compared with those of gears. From this investigation, the following results were obtained. A. In the case of having many teeth gear: As the profile radius is increased, the fillet stresses of the WILDHABER-NOVIKOV gear become the same or less than that of the INVOLUTE gea, and the flank stress becomes smaller than that of the INVOLUTE gear. Therefore the better design condition is satisfied with a large profile radius. B. IN the case of having a few teeth gear: As the profile radius is increased the flank stress of WILDHABER-NOVIKOV gear becomes smaller than that of the INVOLUTE gear, but the fillet stresses become larger than that of the INVOLUTE gear. Therefore the larger design condition is satisfied with small profile radius.