• Journal of Drive and Control
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• v.15 no.3
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• pp.14-20
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• 2018

Wet clutches in an automatic transmission enable the transmission of the engine power by the frictional torque experienced and noted between disk and plates. Since the clutch frictional torque considerably affects the shift quality of an automatic transmission as well as the durability of the machinery, its friction characteristics must be carefully examined to meet the design requirements. The SAE No. 2 friction test machine is a well-known standard to evaluate mainly the friction characteristics of plate clutches along with the required automatic transmission fluids. This paper reviews the experimental analysis of the wet clutch friction characteristics by using the exclusively developed clutch test machine which is capable of controlling the clutch test procedure, in accordance with the applicable test standard and processing of the experimental data automatically. As the clutch test machine is designed for the accommodation of dual clutches which is applied to the real transmission, it can evaluate not only the clutch friction characteristics, but also an actuation performance of a measured clutch piston. In respect to friction characteristics involving dynamic friction coefficients, the energy absorbed in a clutch disk and the recorded temperatures of clutch plates during braking actions and procedures are also investigated. Additionally, the change of friction coefficients by the use of the repeated clutch application is also observed with the endurance test functions of an accurately calibrated and dedicated clutch test machine.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.424-437
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• 2012

As to the increase of crime against children, the importance of safety in school area is more emphasized ever. Safety in school area can be achieved by the well-organized combination of physical, managemental and spatial planning factors. The purpose of this paper is to investigate the spatial planning direction to prevent crimes for the schools and their surroundings on the viewpoint of CPTED(crime prevention through environmental design). Field survey using checklist drawn up with 5 major CPTED principles was conducted for 7 schools(primary, middle and high schools) located at Noen New-town, Daejeon Korea. Problems derived from field survey were categorized to 5 CPTED principles and countermeasures were suggested together with computer graphic simulation. CPTED design principles and guidelines for spatial planning can make school area safer because these can assure natural surveillance, territoriality, natural access control, etc.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.42-54
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• 2008

In recent years, embedded systems have been expanding their application domains from traditional embedded systems such as military weapons, robots, satellites and digital convergence systems such as celluar phones, PMP(Portable Multimedia Player), PDAs(Personal Digital Assistants) to Next Generation Personal Computers(NGPCs) such as eating PCs, wearable computers. The NGPCs are network-based, human-centric digital information devices diverged from the traditional PCs used mainly for document writing, internet searching and database management. Wearable computers with battery capacity and memory size limitations have to use real-time operating systems with small footprints and low power management techniques to provide user's QoS in spite of hardware constraints. In this paper, we have designed and implemented a low-power RTOS (called eRTOS) for wearable computers. The implemented eRTOS has 18KB footprints and the dynamic power management and the device power management schemes are adapted in it. Experimental results with wearable computer applications show that the low power techniques could save energy up to 47 %.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.3
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• pp.72-82
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• 1997

In all inelastic deformations time rate effects are always present to some degree. Whether or not their exclusion has a significant influence on the prediction of the material behaviour depends upon several factors. In the study of structural components under static loading conditions at normal temperature it is accepted that time rate effects are generally not important. However metals, especially under high temperatures, exhibit simultaneously the phenomena of creep and viscoplasticity. In this study, elastoplastic and elasto-viscoplastic models include nonlinear geometrical effects were developed and several numerical examples are also included to verify the computer programming work developed here in this work. Comparisons of the calculated results, for the elasto-viscoplastic analysis of an internally pressurised thick cylinder under plane strain condition, have shown that the model yields excellent results. The results obtained from the numerical examples for an elasto-viscoplastic analysis of the Nuclear Reinforced Concrete Containment Structure(NRCCS) subjected to an incrementally applied internal pressure were summarized as follows : 1. The steady state hoop stress distribution along the shell layer of dome and dome wall junction part of NRCCS were linearly behave and the stress in interior surfaces was larger than that in exterior. 2.However in the upper part of the wall of NRCCS the steady state hoop stress in creased linearly from its inner to outer surfaces, being the exact reverse to the previous case of dome/dome-wall junction part. 3.At the lower part of wall of NRCCS, the linear change of steady state hoop stress along its wall layer began to disturb above a certain level of load increase.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.149-163
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• 2004

Evapotranspiration (ET) is a critical component of the hydrologic cycle which influences economic activities as well as the natural ecosystem. While there have been numerous studies on ET estimation for homogeneous areas using point measurements of meteorological variables, monitoring of spatial ET has not been possible at landscape - or watershed - scales. We propose a site-specific application of the land surface model, which is enabled by spatially interpolated input data at the desired resolution. Gyunggi Province of South Korea was divided into a regular grid of 10 million cells with 30m spacing and hourly temperature, humidity, wind, precipitation and solar irradiance were estimated for each grid cell by spatial interpolation of synoptic weather data. Topoclimatology models were used to accommodate effects of topography in a spatial interpolation procedure, including cold air drainage on nocturnal temperature and solar irradiance on daytime temperature. Satellite remote sensing data were used to classify the vegetation type of each grid cell, and corresponding spatial attributes including soil texture, canopy structure, and phenological features were identified. All data were fed into a standalone version of SiB2(Simple Biosphere Model 2) to simulate latent heat flux at each grid cell. A computer program was written for data management in the cell - based SiB2 operation such as extracting input data for SiB2 from grid matrices and recombining the output data back to the grid format. ET estimates at selected grid cells were validated against the actual measurement of latent heat fluxes by eddy covariance measurement. We applied this system to obtain the spatial ET of the study area on a continuous basis for the 2001-2003 period. The results showed a strong feasibility of using spatial - data driven land surface models for operational monitoring of regional ET.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.27-34
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• 2016

The application of computer graphics, which is characterized by reality, has even reinforced reality of image and motion expression in digital animation. But reality of digital animation succeeds to traditional aesthetic characteristics of animation for overcoming physical limitations of the real world and realizing imagination through transformation, rather than copying actuality as it is. But it does not succeed to drawing animation wholly. Digital animation adds cartoonish transformation, based on three-dimensional realistic expression and those animation situations look as if they get over realistic restrictions, while drawing animation constantly reminds of mediality in drawing motion, based on two-dimensional plane and handwork. n other words, cartoonish exaggeration that is intermittently inserted between these reinforced realities, expresses digital animation's own aesthetic characteristics as a dialectical sum by crashing into contrast coming from a cross between reality and imagination.

• Journal of the Korean Society for information Management
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• v.32 no.4
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• pp.167-203
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• 2015

This study tends to apprehend how much public library contributes to a role of upbuilder of digital integrated local society through a survey. For this, I performed the survey on 935 organization of public library in the whole country registered in national library statistical system. As a result, firstly, it's apprehended that equipment infra, Internet infra, etc like computer, laptop, scanner, tablet PC, etc are in relatively high level. Secondly, service or resource like electronic book, digital and virtual reference service, library service mobile App, etc that users can use are in relatively high level but software supporting cooperation and group task, fusibility of participating space, etc are shown very low level. Thirdly, the rate of literacy training relating to technology were only 22.4%, education subject focused on resource searching subject and somewhat future-oriented technical education like directions of video conference technique, cloud computing application education, etc wasn't conducted. Finally, we should consider expansion of providing technology and equipment and provision of future-oriented service and education according to a flow of the time that needs to seek change in various roles of library as enjoying culture space or creative space.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.1
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• pp.28-32
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• 2014

For a signal such as speech showing piece-wise linear shape in a very short time period, a nonuniform sampling method based on the inflection point detection (IPD) is proposed to reduce data rate. The method exploits the geometrical characteristics of signal further than the existing local maxima/minima detection (MMD) based sampling method. As results, the reconstructed signal by the interpolation of the IPD based sampled data resembles the original speech more. Computer simulation shows that the proposed IPD based method produces about 9~23 dB improvement over the existing MMD method. To show the usefulness of the IPD technique, it is applied to speech coding, and compared to the continuously variable slope delta modulation (CVSD). The nonuniformly sampled data is binary coded with one bit flag set "1". Noninflection samples are not sent, but only flag bits set 0 are sent. The method shows 0.3 ~ 9 dB SNR and 0.5 ~ 1.3 mean opinion score (MOS) improvements over the CVSD.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.187-192
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• 2008

The Intelligent Space(ISpace) provides challenging research fields for surveillance, human-computer interfacing, networked camera conferencing, industrial monitoring or service and training applications. ISpace is the space where many intelligent devices, such as computers and sensors, are distributed. According to the cooperation of many intelligent devices, the environment, it is very important that the system knows the location information to offer the useful services. In order to achieve these goals, we present a method for representing, tracking and human Jollowing by fusing distributed multiple vision systems in ISpace, with application to pedestrian tracking in a crowd. This paper describes appearance based unknown object tracking with the distributed vision system in intelligent space. First, we discuss how object color information is obtained and how the color appearance based model is constructed from this data. Then, we discuss the global color model based on the local color information. The process of learning within global model and the experimental results are also presented.

• Journal of the Korea Society for Simulation
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• v.24 no.1
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• pp.17-24
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• 2015

Smart grid is a modernized electrical grid that uses information and communication technologies to gather and act on information, such as information about the behaviors of suppliers and consumers, in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity. However, with the advent of cyber crime, there are also concerns on the security of the infrastructure, primarily that involving communications technologies. In this work, we make an in-depth investigation on the issue of security services and network loads on Smart grid. Through simulation, we analyze the relations between security services and network loads. The experimental results of this study will contribute toward designing an advanced Smart grid system that offers better quality of services. Also, the approach proposed in this study can be utilized to derive new and valuable insights in security aspects.