• Molecules and Cells
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• v.39 no.3
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• pp.169-178
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• 2016

Although $N{\alpha}$-terminal acetylation (Nt-acetylation) is a pervasive protein modification in eukaryotes, its general functions in a majority of proteins are poorly understood. In 2010, it was discovered that Nt-acetylation creates a specific protein degradation signal that is targeted by a new class of the N-end rule proteolytic system, called the Ac/N-end rule pathway. Here, we review recent advances in our understanding of the mechanism and biological functions of the Ac/N-end rule pathway, and its crosstalk with the Arg/N-end rule pathway (the classical N-end rule pathway).

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.407-412
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• 1997

In this paper, we present a new method to diagnose the characteristics of the soft tissue, especially a liver. In order to diagnose the characteristics of a liver, it is necessary to evaluate the propagation delay time and propagation velocity of bending vibration In a liver. For this purpose, we measure the propagation velocity of bending vibration in a liver for low frequency forced vibration using a standard ultrasonic Doppler diagnosis equipment. We have carried out preliminary experiments by using an ultrasonic probe of 3.5MHz and obtained some results. This new measurement method developed here can be applied to new research and medical fields for acoustic non-invasive diagnosis of soft tissue.

• Journal of Biomedical Engineering Research
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• v.27 no.3
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• pp.101-109
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• 2006

It has been known that there is strong relationship between human voices and the movements of the articulatory facial muscles. In this paper, we utilize this knowledge to implement an automatic speech recognition scheme which uses solely surface electromyogram (EMG) signals. The EMG signals were acquired from three articulatory facial muscles. Preliminary, 10 Korean digits were used as recognition variables. The various feature parameters including filter bank outputs, linear predictive coefficients and cepstrum coefficients were evaluated to find the appropriate parameters for EMG-based speech recognition. The sequence of the EMG signals for each word is modelled by a hidden Markov model (HMM) framework. A continuous word recognition approach was investigated in this work. Hence, the model for each word is obtained by concatenating the subword models and the embedded re-estimation techniques were employed in the training stage. The findings indicate that such a system may have a capacity to recognize speech signals with an accuracy of up to 90%, in case when mel-filter bank output was used as the feature parameters for recognition.

• Journal of Biomedical Engineering Research
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• v.17 no.3
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• pp.379-386
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• 1996

This paper describes an approach for classifying myoelectric patterns using a multilayer perceptrons (MLP's) and hidden Markov models (HMM's) hybrid classifier. The dynamic aspects of EMG are important for tasks such as continuous prosthetic control or vari- ous time length EMG signal recognition, which have not been successfully mastered by the most neural approaches. It is known that the hidden Markov model (HMM) is suitable for modeling temporal patterns. In contrasts the multilayer feedforward networks are suitable for static patterns. Ank a lot of investigators have shown that the HMM's to be an excellent tool for handling the dynamical problems. Considering these facts, we suggest the combination of MLP and HMM algorithms that might lead to further improved EMG recognition systems.

• Journal of Biomedical Engineering Research
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• v.6 no.1
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• pp.19-30
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• 1985

This paper describes the EMG signals in frequency domain using power spectral density, The changes in the moan frequency can represent the energy distribution which results from changing in load before and during fatigue. Most of EMG signal power spectrum is located between 10 and 200Hz. Shifts of the high-energy regions of the power spectra can be inferred from the changes in the mean frequency. If the load is increased without fatigue-ocurring, the high frequency regions have more energy than the low frequency regions. And if load is increased during fatigue, the low frequency regions have more energy than the high frequency regions.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.45-48
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• 1993

High-order field gradients are useful for spatial localization of a volume of interest and dynamic range improvement of signal detection in NMR (Nuclear Magnetic Resonance) spectroscopy and imaging. This paper proposes a design method of shielded high-order gradient coils to reduce tile effect of eddy current on tile spectroscopy and imaging results. According to the experimental results, the shielded gradient coils produce less than 2 % eddy current compared to non-shielded coils. Two shielded $z^2$ gradient coils have been designed and constructed for 1.5 T whole-body and 3.0 T animal NMR imaging systems. Experimental results are in good agreement with the theoretically expected behavior and show the utility of the shielded high-order gradient coils.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.277-280
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• 1995

This paper describes a real time QRS detection algorithm. The proposed algorithm detects QRS complex using characteristics of the 2-dimensional phase portrait which is reconstructed from 1-demensional scalar time series. We observe the phase portrait of ECG signal has special trejectory when QRS complex occurs and apply it to detect QRS complexes. In order to evaluate the performance of the proposed algorithm, we use MIT/BIH arrhythmia database. As a result, the proposed algorithm correctly detects 99.3% of the QRS complexes.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.270-273
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• 1995

중앙 집중식 태아 전자감시 시스템은 태아의 안녕을 판정하는 중요한 평가방법이다. 그러나, 태아감시 시스템은 입력 신호의 장기간의 변동 추이를 검사해야 하며, 따라서 해석하는 사람의 집중력이 쉽게 저하될 수 있다. 컴퓨터를 이용한 태아 감시장치 신호의 자동해석은 분만장의 의사 및 간호사의 업무를 한층 부담없고 손쉽게 할 수 있다. 본 연구에서는 중앙 집중식 태아감시 시스템에서 간단하고 효율적으로 적용할 수 있는 신호 해석 알고리듬을 제시하고, 그에 따른 고속 프로그램을 구현하여 실제 시스템에 적용해 봄으로써 신호 해석 알고리듬의 실효성을 검토해 보고자 한다.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.81-85
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• 1993

Despite the simplicity of processing, conventional autocorrelation function (ACF) method for the precise determination of fetal heart rate (FHR) has many problems. In the case of weak or noise corrupted Doppler ultrasound singnals, the ACF method is very sensitive to the threshold level and data window length. It is real troublesome to extract FHR when there is a data loss. To overcome these problems, the high resolution pitch detection algorithm is adapted to estimate the FHR. The FHR is determined from the correlation of two interconnected segments by its maximum correlation value. FHR is compensated with a constant correlation threshold in a greatly smeared noise signal. This method yields more accurate, robust and reliable than the ACF method.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.116-119
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• 1993

In this paper, we implemented a pulse wave type oximeter system that continuously measure the of oxyhemoglobin saturation of the arterial blood(SaO2) and pulse rate with non-invasively. We use the transmission type and reflection type transducer for comparison the percentage of hemoglobin oxgen saturation. The light Iron the two kind of LEDs is transmitted through the tissue, then received by a single photodiode with alternatively. By the phase sensitive detection circuit, the output of the photodiode is separated in to red and near infrared signal. We calculated a ratio of light transmittance between two kind of LEDs, and then, it is applied to the oxgen saturation coefficent calculation formular.