• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.544-550
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• 2006

The interaction between people and sound and the way how people consciously perceive their environment are central approach to soundscape research. In this respect, this paper aims to clarify the relationship between water-sound level and recognition region in urban area. As a passive soundscape facility, fountain is a useful way to give place such as public square, park identity and vitality. In this study, to know the optimistic distance and sound level range from fountain, sound levels due to distance were measured and subject responses were checked by questionnaire. As a result, levels from 63 dB to 67 dB were recommended by subjects and moving forward to fountain less satisfactory than backward. Moving forward 5 m and backward 5 m(total range 10 m): there was a difference in satisfaction ratio by 2,5 out of 10. The results of this study could be used for street furniture location design and P.A. system output level.

• Journal of the Korean Society for Library and Information Science
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• v.53 no.4
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• pp.361-372
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• 2019

The Overseas Construction Engineering Information System (OVICE), which is operated by the Korea Institute of Construction Technology, uses the Overseas Construction Information Service classification system to service information required for overseas construction of domestic construction engineering companies. In this study, through the application of the recommendation system using collaborative filtering, identifying the relationship between the subjects for real users, verifying the adequacy of the overseas construction information classification system currently in service. Through this, I would like to propose an information service classification system that reflects actual user demand.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.127-136
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• 2005

This paper measured a proper ratio of the size of demand fetch cache $L_1$ to that of prefetch cache $L_P$ by imulation when the size of $L_1$ and $L_P$ are constant which organize space-limited level 1 cache of a single microprocessor chip. The analysis of our experiment showed that in the condition of the sum of the size of $L_1$ and $L_P$ are 16 KB, the level 1 cache organization by constituting $L_P$ with 4 KB and employing OBL and FIFO as a prefetch technique and a cache replacement policy respectively resulted in the best performance. Also, this analysis showed that in the condition of the sum of the size of $L_1$ and $L_P$ are over 32 KB, employing dynamic filtering as prefetch technique of $L_P$ are more advantageous and splitting level 1 cache by constituting $L_1$ with 28 KB and $L_P$ with 4 KB in the case of 32 KB of space are available, by constituting $L_1$ with 48 KB and $L_P$ with 16 KB in the case of 64 KB elicited the best performance.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.276-280
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• 2006

최근, 국가적인 차원에서 추진되고 있는 대체에너지 전원은 배전계통에 연계되어 운용되는 특성을 가지고 있다. 이들 전원은 대부분 반도체를 이용한 전력변환기기를 사용하기 때문에 60Hz의 상용주파수의 정수배에 해당되는 주파수 성분의 전류를 발생시켜 전력계통에 역으로 유출하게 된다. 계통에 유입된 고조파는 배전선로와 변압기 등의 계통 각 구성요소의 임피던스에 의하여 고조파전압을 발생시켜, 다른 기기에 왜곡된 파형의 전압을 공급하게 되어, 기기의 정상적인 동작을 방해하거나 경우에 따라서는 기기를 손상시키는 원인이 되기도 한다. 따라서 본 연구에서는 이들 고조파 발생기기가 계통에 악영향을 미치지 않는 적정한 레벨의 고조파 수준을 산정하는 알고리즘을 제시하고, 이 값을 근거로 고조파를 억제하는 대책방안을 제시하고자 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.731-737
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• 2000

In this paper we propose a decoding algorithm of Ungerboeck TCM/PSK in the concept of Radix-trellis, which has been applied to the decoding of convolutional codes for the high speed decoding. As an example we choose 16-state trellis coded 8-ary PSK. For Radix-4 and Radix-16 trellis decoding, we explain the path metric(PM) and the branch metric(BM) calculation. By using the simulation, we evaluate the bit error rate(BER) performance according to the number of binary digits for I-Q value, PM and BM registers. The proper number of binary digits of each register has been derived.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.499-509
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• 2005

The capacity of Satellite DMB(Digital Multimedia Broadcasting) system is limited mainly by the interference. So, to achieve the expected performance of Satellite DMB system and to minimize the interference from other Satellite DMB system, ACI(Adjacent Channel Interference) should be considered carefully. Satellite DMB system uses the Gap-filler for effective transmission in terrestrial environment, and the Gap-filler can use direct amplification or frequency conversion to satisfy the specific requirements. Therefore, amplified signal causes several effects on interference between System A(Eureka 147 DAB) and System E(ISDB : Integrated services Digital Broadcasting). In this paper, by using the outcome of system-level simulation considering the results of link-level simulation, we analyze the interferences between System A and System E under practical situation based on the exact parameters of ITU-R BO. 1130-4. We also propose the appropriate level of guard band and Cell Radius to optimize system capacity by adapting the spectrum mask given in the spec. and utilizing the interference analysis between System A and System E.

• Journal of IKEEE
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• v.17 no.3
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• pp.317-323
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• 2013

In this paper, 25W wireless power transmission(WPT) system using the coupled magnetic resonance is presented. The WPT system consists of a 100W class-F power transmitter, 1.7MHz magnetic resonators and a 40W full-bridge receiver using diodes. Especially, the transmit power control function using the 400MHz FSK communication between the transmitter and the receiver is adopted in the proposed system for the stable power transmission. Using the system and the power control function, the WPT system can be adopted in the various electronic devices and the commercialization of WPT system can be moved forward.

• The Journal of the Acoustical Society of Korea
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• v.36 no.5
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• pp.329-337
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• 2017

In USA and UK, the standards of both reverberation time and background noise level have been established for the appropriate aural environment in classrooms. In order to realize this, guidelines for architectural planning and interior finishing have been also suggested. However, in Korea, there has hardly been any guidelines for satisfying background noise criteria and investigation about sound insulation performance of current walls of classrooms. The present study investigates the structure of outer wall and walls between classrooms of two middle schools in order to analyze the sound insulation performance against both exterior and interior noises. Acoustic parameters including transmission loss, standardized sound level difference, and signal to noise ratio have been measured and analyzed for sound insulation performance of walls and flanking noises. As a result, concerning the walls in between classrooms, it was found that walls of dry construction have greater sound insulation performance rather than the walls of wet construction especially in mid and high frequency bands. Also, It was revealed that thermopane, insulated pair glass, of outer walls, has greater sound insulation performance than the double window consisted of two single pane glass. Regarding flanking noises, the standards were exceeded when all windows, or windows and doors front onto corridor were opened. It denotes that students could be disturbed with the sound transmission by the interior noises.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2083-2090
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• 2008

In this paper, we propose a method for control of temperature and the direction of wind in an air-cooler using thermal images and fuzzy inference rules in order to achieve energy saving. In a simulation for controlling temperature, a thermal image is transformed to a color distribution image of $300{\times}400$ size to analyze the thermal image. A color distribution image is composed of R, G and B values haying temperature values of Red, Magenta, Yellow, Green, Cyan and Blue. Each color has a temperature value from $24.0^{\circ}C$ to $27.0^{\circ}C$ and a color distribution image is classified into height hierarchies from level 1 to level 10. The classified hierarchies have their peculiar color distributions and temperature values are assigned to each level by temperature values of the peculiar colors. The process for controlling overall balance of temperature and the direction of wind in an indoor space is as follows. Fuzzy membership functions are designed by the direction of wind, duration time, and temperature and height values of a color distribution image to calculate the strength of wind. After then, the strength of wind is calculated by membership values of membership functions.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.635-640
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• 2009

After 1960s, in accordance with getting bigger in changing range of annual rain precipitation, those dams were built in order to prevent any drought and flood through the regulation of flux. In case of such dam, when it reaches to some definite pondage, for its regulation of water volume, numerous volume of water in the reservoir should be discharged by opening the floodgate, at this time a severe damage can be occurred to those lives and properties of the residents and tourists at the river or riverside. Accordingly, despite the sounding alarm broadcasting for prevention and notice such damage could be clearly travelled to those people without influence by the discharging noise or other neighboring environmental factor, since it was only empirically installed without any peculiar research until now, the alarm broadcasting could not effectively travel, and the travelling distance also could not known correctly. On such point of view, this Study has ever grasped the characteristics by frequencies and its sound pressure level about the discharge noise and the alarm broadcasting of Daechung Dam, one of multipurpose dams through the measurement and analysis by distances, and based on this, also has ever presupposed the proper location of additional alarm broadcasting spot using a simulation program named Cadna-A.