• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.150-155
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• 2006

This study observes information education of facilities for the disabled. A certain facility for the disabled was selected in Daejeon to compare the educational environment for visually disabled of regular school for visually disabled and facilities for the disabled, and then personnel current situation by age and form of the disabled, teacher current situation by age, computer possessing current situation, weekly education schedule for the disabled, and equipment possessing current situation for visually disabled were observed. As a result, expansion of Braille education was necessary for the Braille skilled, which is the basis of information education information to visually disabled is insufficient, and forming of learning environment was desperate since equipment necessary for computer education was absurdly lacking unlike regular schools. Also, only 10 out of 21 teachers(47%) majored in social welfare or special education, and none majored in computer. It is because support for employment of those who majored social welfare, special education, and computer is insufficient compared to treatment for teachers at general schools at the facility for the disabled since teacher employment regulation at the facility for the disabled is not set. It is studied that providing high-quality of education environment to the disabled was desperate through physical and social treatment that suits nurturing of the professionally knowledge personnel through expansion of equipments and constant education and training based on government support to promote information education of the facility for the disabled.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.73-84
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• 2018

Recently, the importance of flame retardation treatment technology has been emphasized due to the increase in urban fire accidents and fire damage incidents caused by building exterior materials. Particularly, in the utilization of wood-based building materials, the flame retarding treatment technology is more importantly evaluated. An Intumescent system is one of the non-halogen flame retardant treatment technologies and is a system that realizes flame retardancy through foaming and carbonization layer formation. To apply the Intumescent system, composite material was prepared by using Ethylene vinyl acetate (EVA) as a matrix. To enhance the flame retardant properties of the Intumescent system, a nano-clay was applied together. Composite materials with Intumescent system and nano - clay technology were processed into sheet - like test specimens, and then a new structure of cross laminated timber with improved flame retardant properties was fabricated. In the evaluation of combustion characteristics of composite materials using Intumescent system, it was confirmed that the maximum heat emission was reduced efficiently. Depending on the structure attached to the surface, the CLT had two stages of combustion. Also, it was confirmed that the maximum calorific value decreased significantly during the deep burning process. These characteristics are expected to have a delayed combustion diffusion effect in the combustion process of CLT. In order to improve the performance, the flame retardation treatment technique for the surface veneer and the optimization technique of the application of the composite material are required. It is expected that it will be possible to develop a CLT structure with improved fire characteristics.

• Korean Security Journal
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• no.14
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• pp.485-516
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• 2007

Jeju Special Self-Government Province adopted an autonomous police system for the first time since 60 years in Korean police. The purpose of autonomous police system is to offer a police service to be suitable in regional conditions. But Jeju autonomous police system for nearly one year after adoption is criticized to be established on the ground of political reason but not local decentralization. Actually Jeju autonomous police has not a clear cut jurisdiction and operation scope because of the jurisdiction duplication between national and autonomous police. The original task is confined on environment and sightseeing so on given to administration police for local self-government. So criminal investigation authority on general crimes is not to Jeuju autonomous police on account of special judicial police. First, it is the structural rationalization of Jeju autonomous police system. It speaks that Jeju provincial police bureau and police station have to be as national police institution, on the other hand, patrol district station and police box have to be as autonomous police institution. Of course, functional division has to be followed. National police performs managing all the assembly and demonstration by the management law on assembly and demonstration including the suppression against any large scale demonstration and disturbance, also the investigation on serious crimes just as international crimes and broaden area crimes including all the felony. Together national police performs the duty concerned to all the foreign affairs and national securities in along with the investigation on traffic accidents. On the other hand, autonomous police performs the function for citizen's life safety as crime prevention and the enforcement on the violation against police operation law, together the traffic management and the regulation on traffic violations. and the investigation on minor crime as simple violence or petty larceny including the management on local big events. Second, the budgetary of autonomous police is rationalized by the share of budgeting between Korean government and Jeju special self-government province. Third, urgent arrest authority on general crime and the rights of claims for the summary trial on minor crimes are given to autonomous police. Of course, this problem is resolved naturally in case of giving the investigation rights to autonomous police on minor crimes.

• Particle and aerosol research
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• v.6 no.3
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• pp.107-121
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• 2010

The number of nanotechnology based consumer products are growing rapidly. Thus, the customer likely to be exposed to such products continues to increase as the applications expand. This article describes the international and Korea's policies on the EHS(Environment, Safety and Health) issues of nanotechnologies. The strategic plan and coordination of OECD and ISO were summarized. This article also examines several new findings of Korean researchers as well as current and future challenges in the aerosol application study of EHS issues on the nanotechnologies.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.136-146
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• 1999

A series of experiments were carried out in winter to investigate the indoor thermal environment in greenhouses with different kinds of heating systems, and characterize the energy consumption, heat transport and thermal energy efficiency of each system. By the Quantitative calculation of heat losses which transmit through the covers of greenhouse, the fundamental data of energy-saving of the particular heating system were obtained. And from the analysis of air temperature differences between indoor and outside, it was possible to select more effective energy-saving and comfortable heating system in greenhouses. The electric heater was more stable in thermal environment and cheaper in cost, since it could be used during the surplus time of electric power from 10：00 p.M. to 8：00 A.M. But the low air temperature in greenhouses besides these times resulted in a chilling problem of the crops. The heating system by hot air had the advantage to show nearly uniform temperature difference by the height above the ground. But the system had the disadvantage to require more energy consumption than the electric heating system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.16-23
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• 2006

This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high power-factor. The proposed topology is integrated half-bridge boost rectifier as power factor corrector(PFC) and half-bridge high frequency resonant converter into a single-stage. The input stage of the half-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. Simulation results have demonstrated the feasibility of the proposed high frequency resonant converter. Characteristics values based on characteristics analysis through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, fluorescent lamp and DC-DC converter etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.110-122
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• 1993

When voice is transmitted through packet switching network, there needs a overload control, that is, a control for the congestion which lasts short periods and occurrs in local extents. In this thesis, we analyzed the performance of the statistical packet voice multiplexer using the overload control strategy by bit dropping. We assume that the voice is coded accordng to (4,2) embedded ADPCM and that the voice packet is generated and transmitted according to the procedures in the CCITT recomendation G. 764. For the performance analysis, we must model the superposed packet arrival process to the multiplexer as exactly as possible. It is well known that interarrival times of the packets are highly correlated and for this reason MMPP is more suited for the modelling in the viewpoint of accuracy. Hence the packet arrival process in modeled as MMPP and the matrix geometric method is used for the performance analysis. Performance analysis is similar to the MMPP IG II queueing system. But the overload control makes the service time distribution G dependent on system status or queue length in the multiplexer. Through the performance analysis we derived the probability generating function for the queue length and using this we derived the mean and standard deviation of the queue length and waiting time. The numerical results are verified through the simulation and the results show that the values embedded in the departure times and that in the arbitrary times are almost the same. Results also show bit dropping reduces the mean and the variation of the queue length and those of the waiting time.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.55-61
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• 2010

This paper is concerned with an experimental research to random vibration control caused by external loads specially in bridges which tend to be structurally flexible. Experimenting on a reduced structure modelled on Seohae Grand Bridge, we inflicted a reduced form of El-centro wave on the model structure to a proper proportion. On the center of its middle span, we placed a shear type MR damper which was to control its vibration and also acquire its structural responses such as displacement and acceleration at the same site. The experiments concerning controlling vibration were performed according to a variety of theories including un-control, passive on/off control, and Lyapunov stability theory. Its control performance was evaluated in terms of the peak absolute displacements, the peak absolute accelerations and the total power required to control the bridge which differ from each different experiment method. Among all the methods applied in this paper, case of Lyapunov control method turned out to be the most effective to reduces of displacement and acceleration. Also, this method could to decrease consuming of external power for vibration control. Finally, it was noteworthy that Lyapunov control method was specially effective in the vibration control employing a semi-active damper such MR damper.

• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.46-52
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• 2011

A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.122-132
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• 2010

AT-DMB system has been developed to increase data rate up to double of conventional T-DMB in the same bandwidth while maintaining backward compatibility. The AT-DMB system adopted hierarchical modulation which adds BPSK or QPSK signal as enhancement layer to existing DQPSK signal. The enhancement layer signal should be small enough to maintain backward compatibility and to minimize the coverage loss of conventional T-DMB service coverage. But this causes the enhancement layer signal of AT-DMB susceptible to fading effect in transmission channel. A turbo code which has improved error correction capability than convolutional code, is applied to the enhancement layer signal of the AT-DMB system for compensating channel distortion. However there is a need for other solutions for better reception of AT-DMB signal in receiver side without increasing transmitting power. In this paper, we propose adaptive array antenna system with Eigen-space beamforming algorithm which benefits beamforming gain along with diversity gain. We analyzed the reception performances of AT-DMB system in indoor and mobile environments when this new smart antenna system and algorithm is introduced. The computer simulation results are presented along with analysis comments.