• 한국자동차공학회논문집
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• 제8권6호
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• pp.1-8
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• 2000

A new method of knock detection in SI engines, using a change of ion concentration in the combustion chamber, was developed. In order to measure in-cylinder ionization current, ionization probes were installed at spark plug and cylinder head of production engine. It was found that the electric current generated by ionized gas in core burned gas region of knocking cycle is between 2 and 10 times larger than that of normal cycle, because the burned gas temperature which is the dominant parameter of a change of ion concentration increases. However, a change of ionization current in boundary region of burned gas is relatively weak. Hence a change of ion concentration in core burned gas region can be used for knock detection.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.23-31
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• 2000

Knock and misfire, kinds of abnormal combustion, are highly undesirable effect on the internal combustion engine. So, it is important to detect these avnormal combuition and control the ignition timing etc. to avoid these mal-effect factors in real engine system. In this study, the system which detects the knock and the misfire using by spark plug is presented. This system is based on the effect of modulation breakdown voltage(BDV) between the spark gaps. The voltage drop between spark plug electrodes, when an electrical breakdown is initiated, depends on the temperature and pressure in combustion chamber. So, we can detect knock and misfire that produce changes in gas temperature and pressure (consequently, its density) using by BDV signal change which carries information about the character of combustion.

• International Journal of Automotive Technology
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• 제8권3호
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• pp.259-268
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• 2007

A knock detection circuit that is based on the signal of an accelerometer installed on the engine block of a spark ignition automotive engine has a band-pass filter with a certain frequency as a parameter to be calibrated. A new statistical method for the determination of the frequency which is the most suitable for the knock detection in real-time applications is proposed. The method uses both the cylinder pressure and block vibration signals and is divided into two steps. In both steps, a new recursive trigonometric interpolation method that calculates the frequency contents of the signals is applied. The new trigonometric interpolation method developed in this paper improves the performance of the Discrete Fourier Transformation, allowing a flexible choice of the size of the moving window. In the first step, the frequency contents of the cylinder pressure signal are calculated. The knock is detected in the cylinder of the engine cycle for which at least one value of the maximal amplitudes calculated via the trigonometric interpolation method exceeds a threshold value indicating a considerable amount of oscillations in the pressure signal; this cycle is selected as a knocking cycle. In the second step, the frequency analysis is performed on the block vibration signal for the cycles selected in the previous step. The knock detectability, which is an individual cylinder attribute at a certain frequency, is verified via a statistical hypothesis test for testing the equality of two mean values, i.e. mean values of the amplitudes for knocking and non-knocking cycles. Signal-to-noise ratio is associated in this paper with the value of t-statistic. The frequency with the largest signal-to-noise ratio (the value of t-statistic) is chosen for implementation in the engine knock detection circuit.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.28-35
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• 1999

In this study, investigation of transient knock characteristics in a spark-ignition engine has been carried out. The universal knock threshold values were found by a DFDD method and a NSDBP method which is a non-dimensional version of the SDBP method. Also modified NSDBP method could be used for transient knock detection. In a commercial ECU , spark timing was retarded from the steady -state spark timing during rapid throttle opening to avoid uncomfortable feeling and knock. Knock usually occurred just after the start of rapid throttle opening when spark timing was set, as values for the steady state condition. We found that air/fuel ratio deeply involved with the knock during transient condition. Due to the difference of initial heat release rate, knock occurred more easily at rich air/fuel ratio than at lean air/fuel ratio.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.17-23
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• 2000

Knock in SI engines causes physical damage to the piston and combustion chamber and lowers the thermal efficiency. The increase in compression ratio which can improve the thermal efficiency and engine performance has been limited by engine knock. So the need of making clear the knocking phenomenon has increased. This paper reviews the methods of knock detection, characterization and prediction of knock with the reduced chemical kinetic modeling.

• 한국연소학회지
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• 제5권2호
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• pp.29-35
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• 2000

Knock in SI engines causes physical damage to the piston and combustion chamber and lowers the thermal efficiency. The increase in compression ratio which can improve the thermal efficiency and engine performance has been limited by engine knock. So the need of making clear the knocking phenomenon has increased. This paper reviews the methods of knock detection, characterization and prediction of knock with the reduced chemical kinetic modeling.

• 한국자동차공학회논문집
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• 제1권3호
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• pp.12-21
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• 1993

In recent years, high efficiency, high performance, and low pollutant emmision engines have been developed. Knock phenomenon has drawn interests because it became an hinderance to engine power and efficiency increase through higher compression ratio. Knock phenomenon is an abnormal combustion originated from autoignition of unburned gas in the end-gas region during the later stage of combustion process and accompanied a high pitched metallic noise. And this phenomenon is characterized by knock occurrence percentage, knock occurrence angle and knock intensity. A four cylinder spark ignition engine is used in our experiment, and its combustion chamber pressure is measured at various engine speeds, ignition timing. The data are analyzed by numerous methods in order to select the optimum methods and to achieve better understanding of knock characteristics. Methods using band-pass filter, third derivative and step method are shown to be the most suitable, while methods using frequency analysis are shown to be unsuitable. Because step method only uses signals above threshold value during knocking condition, pressure signal analyses with this method show good signal-to-noise ratio.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6625-6629
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• 2013

Breast cancer accounts for one third of new cancer cases among women. The need for biomarkers for early detection is the stimulus to researchers to evaluate altered expression of genes in tumours. Cancer-testis (CT) genes are a group with limited expression in normal tissues except testis but up-regulation in a wide variety of cancers. We here evaluated expression of two CT genes named FBXO39 and TDRD4 in 32 invasive ductal carcinoma samples, 10 fibroadenomas and 6 normal breast tissue samples, in addition to two breast cancer cell lines, MCF-7 and MDA-MB-231, by the means of quantitative real time RT-PCR. FBXO39 showed significant up-regulation in invasive ductal carcinoma samples in comparison with normal samples. It also was expressed in both cell lines and after RHOXF1 gene knock down it was down-regulated in MCF-7 but up-regulated in the MDA-MB-231 cell line. TDRD4 was not expressed in the MCF-7 cell line and any of the tissue samples except testis. However, it was expressed in MDA-MB-231 and was up-regulated after RHOXF1 gene knock down. Our results show that FBXO39 but not TDRD4 can be used for cancer detection and if proved to be immunogenic, might be a putative candidate for breast cancer immunotherapy.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제11권11호
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• pp.411-418
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• 2022

최근 항만에서는 부정확한 컨테이너 적재로 인해 컨테이너가 강풍에 쉽게 쓰러지는 컨테이너 붕괴 사고가 빈번이 발생하고 있으며 이는 물적 피해와 항만 시스템 마비로 이어지고 있다. 본 논문에서는 이런 사고를 미연에 방지하기 위해 딥러닝 기반 컨테이너 적재 상태 및 사고 위험도 검출 시스템을 제안한다. 제안된 시스템은 darknet 기반 YOLO 모델을 활용하여 컨테이너 상하의 코너캐스팅을 통해 컨테이너 정렬 상태를 실시간으로 파악하고 관리자에게 사고 위험도를 알리는 시스템이다. 제안된 시스템은 추론 속도, 분류 정확도, 검출 정확도 등을 성능 지표와 실제 구현 환경에서 최적의 성능을 보인 YOLOv4 모델을 객체 인식 알고리즘 모델로 선택하였다. 제안된 알고리즘인 YOLOv4가 YOLOv3보다 추론속도와 FPS의 성능 측면에서 낮은 성능을 보이기는 했지만, 분류 정확도와 검출 정확도에서 강력한 성능을 보임을 증명하였다.

• 약학회지
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• 제56권6호
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• pp.377-381
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• 2012

The histidine-rich $Ca^{2+}$ binding protein (HRC) is a $Ca^{2+}$ binding protein in the sarcoplasmic reticulum (SR). In this study, we examined whether the HRC is involved in the regulation of cardiac contraction and $Ca^{2+}$ signaling using HRC knock-out (KO) mouse ventricular myocytes. In field-stimulated single mouse ventricular myocytes, cell shortenings and $Ca^{2+}$ transients were measured using a video edge detection and a confocal $Ca^{2+}$ imaging, respectively. Compared with the wide-type (WT) myocytes, the magnitudes of cell shortenings were significantly larger in HRC KO cells (P<0.01, WT vs. KO). The rate of contraction and relaxation was significantly accelerated in HRC KO myocytes (P<0.05 and P<0.01, respectively, WT vs. KO). The magnitudes of $Ca^{2+}$ transients were increased by HRC KO (P<0.01, WT vs. KO). In addition, the decay of the $Ca^{2+}$ transient was faster in HRC KO cells than in wild-type cells P<0.01, WT vs. KO). These results suggest that HRC may suppress SR $Ca^{2+}$ releases and decay of $Ca^{2+}$ transients during action potentials, thereby attenuating ventricular contraction and relaxation.