• ETRI Journal
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• v.18 no.2
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• pp.61-74
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• 1996

We propose two new rate control schemes to improve MPEG-2 rate control in view of visual quality when scene changes happen. Two proposed schemes are characterized by real-time and non real-time improvement to reduce the impact of scene changes. We also propose a new target-bit prediction method using spatial activity of pictures and present a simple and efficient scene change detection scheme using signed difference of mean absolute difference (MAD). Computer simulation results show that the proposed real-time algorithm effectively alleviates visual quality degradation after scene changes. The proposed non real-time algorithm gives maximum 2 dB improvement in peak signal-to-noise ratio (PSNR) at a scene-changed picture, compared with MPEG-2 rate control scheme and it shows better quality than the real-time one.

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.285-294
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• 2002

This study is focused on the operation of truck with conscious for environmental logistics system to reduce empty truck movements, and to control running empty truck. With the logistics function, road transport represents the biggest environmental threat. Using nonrenewable natural resources, contributing to air and noise pollution, trucks are environmentally unfriendly. Any steps to reduce transport activity will help minimize negative impact. In particular, noxious emissions must be reduced, but in the long term more environmentally friendly vehicles are required.

• The Journal of the Acoustical Society of Korea
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• v.32 no.6
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• pp.541-547
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• 2013

The speech quality of multi-party audio telephony between two, three or more participants is decreased by audio volume imbalance, audio volume saturation and noise level increase. To solve this issue, this paper proposes an advanced audio mixing algorithm for software-based multi-point control unit. Our approach is based on the combined voice activity detection and gain control technique that consists of a set of algorithms that classify audio signals, estimate audio volumes, adjust gain factors and mix audio signals of all channels. The proposed audio mixing algorithm is computationally efficient, delivers high-quality speech, and is suitable for use in any practical multi-party audio telephony.

• Journal of Biomedical Engineering Research
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• v.27 no.4
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• pp.154-163
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• 2006

A 64-channel magnetocardiogram (MCG) system using low-noise superconducting quantum interference device (SQUID) planar gradiometers was developed for the measurements of cardiac magnetic fields generated by the heart electric activity. Owing to high flux-to-voltage transfers of double relaxation oscillation SQUID (DROS) sensors, the flux-locked loop electronics for SQUID operation could be made simpler than that of conventional DC SQUIDs, and the SQUID control was done automatically through a fiber-optic cable. The pickup coils are first-order planar gradiometers with a baseline of 4 em. The insert has 64 planar gradiometers as the sensing channels and were arranged to measure MCG field components tangential to the chest surface. When the 64-channel insert was in operation everyday, the average boil-off rate of the dewar was 3.6 Lid. The noise spectrum of the SQUID planar gradiometer system was about 5 fT$_{rms}$/$\checkmark$Hz at 100 Hz, operated inside a moderately shielded room. The MCG measurements were done at a sampling rate of 500 Hz or 1 kHz, and realtime display of MCG traces and heart rate were displayed. After the acquisition, magnetic field mapping and current mapping could be done. From the magnetic and current information, parameters for the diagnosis of myocardial ischemia were evaluated to be compared with other diagnostic methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.720-724
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• 2007

Recently, in accordance with increase of the desire for Sports for All(Life Sports), the swimming pools in many areas are under construction. However, since they used many of the reflexible finish-materials on account of the characteristics of hydrophilic space, most of the Indoor Swimming Pools are generating the excessive reverberation. Such reverberation is bringing about the problem that obstructs the oral communication between the coach and the player, and the Clearness of Sound, besides the sport activity. On this viewpoint, on the object of the actually built indoor swimming pool, after the conduct of an optimized acoustics design by the remodeling through a computer simulation, and by carrying out the Psycho-Acoustics Experiment utilizing of Auralization Technique which is able to experience Virtual Sound Field at the stage of designing, then this thesis has attempted to appraise on the acoustic condition after the completion of construction. It is considered that such result of the study could be utilized as the useful data that enables to improve the curtailment effect of construction cost as well as the acoustic capability, by means of the presupposition control on the acoustic problem from the stage of design, for the occasion when the similar indoor swimming pool is planning to build, henceforth.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.696-700
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• 2007

In case of dome-typed gymnastics training floor, since its form takes shape of the focus of sound, in the occasion when the finishing-material was used with the sandwich panel that prominent in reflexibility, and because the reverberation of sound in indoor is too loud, a smooth practice and teaching is very difficult. As this indoor gymnastics training floor, standing at its character, is required simultaneously the idea communication between the player and the coach, and the acoustic capability regarding to the clearness of music, besides the sport activity, the method to minimize the acoustic defect should be urgently contrived from the stages of design and beginning of construction. On this viewpoint, after investigation on the confidence of the surveyed value and the estimated value using acoustic simulation, and use of the changed finish-material, this thesis intends to design the dome-typed gymnastics training floor that secured the optimized acoustic condition. It is also considered that such result of the study could be utilized as the useful data that enables to improve the retrenchment effect of the construction cost as well as the acoustic performance, by means of the prediction control on the acoustic problem from the stage of design, for the occasion when the similar indoor sport gymnasium is planning to build for the near future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.623-627
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• 2007

In case of the Grand Performance Hall, in view of its distinctiveness, since various Assembly Activity as well as Lecture together with the use for Music are important besides the purpose of Performance itself, the consideration with regard to the sound environment which enables to minimize the acoustic defect has appeared on the stage as an essential factor. On this viewpoint, this Study has attempted to examine the acoustic satisfaction degree and its response regarding to the grand performance hall by means of the measurement and valuation about the psychological volume of human-being using the auditory-evoked technology that possible to experience the Virtual Sound Field at the designing stage, after practice of the optimized acoustic design for the object of the grand performance hall on the step of construction. As the result of auditory-evocation, it was known that the valuation about the acoustic performance after reformation has been improved affirmatively than before reformation. It is considered that such outcome of the study could be utilized as the useful material that enables to improve the curtailment effect of construction cost and the acoustic performance, by means of the presupposition control about the acoustic problem from the stage of design, for the occasion when the similar Performance Hall is planning to build, hereafter.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.708-719
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• 2007

In case of indoor gymnastics training floor, in view of its characteristics, since it is simultaneously required the related smooth communication between the coach and the player, also the acoustic performance regarding to the clearness of music, besides the sport activity, the consideration about the acoustic character has entered the stage as an indispensable element. On such viewpoint, recently constructed dome-typed gymnastic training floor was optimized acoustic design with remodeling through acoustic simulation test. And acoustic satisfaction degree and reaction was attempted to investigate about the gymnastics training floor estimating value of human's psychological(sensual) degree using auralization that enables to experience the virtual sound field at the stage of design. As the result of investigation about the research on the space of object, it could be known that the valuation regarding to the acoustic performance of 'after-improvement' was distinctly more refined than that of 'before-improvement'. It is now considering that such result of the study can be utilized as the useful data which enables to improve the retrenchment effect of the construction cost as well as the acoustic capability, by means of the prediction control on the acoustic problem from the stage of design, for the occasion when the similar indoor sport gymnasium is planning to build for the near future.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.32-38
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• 1999

In this study, an objection is to develop a electronic circuit of a gauage using radioisotope for compaction control to be needed at public works The developed gauage makes use of radioisotope with the activity exempted from domestic atomic law and consists of measuring circuits for gamma-rays and thermal neutrons, a high voltage supply unit and a microprocessor. To obtain meaningful numbers of pulse counts, parallel five and tow circuits are provided for gamma-rays and thermal neutrons, respectively. Also, to minimize effects of natural environmental radiation and electrical noise, circuits are electrostatically shielded and pulses made by ripples are eliminated by taking frequency of high voltage supplied to the circuit and pulse height of ripples into consideration One-chip microprocessor is applied to process various counts, results are stored, Enough and meaningful numbers of pulses are counted with the prototype gauage for compaction control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.252-260
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• 2021

For frailty management, the importance of resistance exercise has been emphasized, and various devices have been developed. Recently, digital weight control technology that converts electromagnetic resistance to a digital weight is attracting attention, but there are no reports confirming the effectiveness and safety of the device for seniors in Korea. This study conducted a biomechanic-based ergonomic analysis of an elderly-friendly exercise device utilized in digital load control technology to suggest a direction for development. Twenty seniors (age: 62.40 ± 2.09 years) were included. The load of the device was classified into three levels, and the muscle activity and heart rate were assessed during three experimental motions. A questionnaire based on the International Organization for Standardization 9241-11 was adopted to evaluate the stability, operationality, efficiency, and satisfaction with the software and device. The program could be divided into three exercise intensities that can be utilized in the field depending on whether the exercise load, muscle activity, and heart rate were consistent. The monitor size needed to be enlarged to make the menu Korean, reduce the device size, and minimize noise. Considering these findings, the development of an advanced age-friendly exercise device by improving the size, display, and noise is suggested.