• The Transactions of the Korean Institute of Power Electronics
• /
• v.22 no.3
• /
• pp.185-192
• /
• 2017

This paper proposes a single-stage interleaved soft-switching electrolytic capacitor-less EV charger with reduced component count and simple circuit structure. The proposed charger achieves ZVS turn-on of all switches and ZCS turn-off of all diodes without regard to voltage and load variation. It achieves high power density even without an input filter due to CCM operation and bulky electrolytic capacitors and without a low-frequency component in the transformer. A 2 kW prototype of the proposed charger with sinusoidal charging is built and tested to verify the validity of the proposed operation.

• Korean Journal of Agricultural Science
• /
• v.38 no.4
• /
• pp.761-767
• /
• 2011

The objective of this study was to predict total bacteria count of pork meats by using the portable electronic nose systems developed throughout two stages of the prototypes. Total bacteria counts were measured for pork meats stored at $4^{\circ}C$ for 21days and compared with the signals of the electronic nose systems. PLS(Partial least square), PCR (Principal component regression), MLR (Multiple linear regression) models were developed for the prediction of total bacteria count of pork meats. The coefficient of determination ($R_p{^2}$) and root mean square error of prediction (RMSEP) for the models were 0.789 and 0.784 log CFU/g with the 1st system for the pork loin, 0.796 and 0.597 log CFU/g with the 2nd system for the pork belly, and 0.661 and 0.576 log CFU/g with the 2nd system for the pork loin respectively. The results show that the developed electronic system has potential to predict total bacteria count of pork meats.

• Journal of Biosystems Engineering
• /
• v.29 no.3
• /
• pp.261-266
• /
• 2004

This study was Performed to classify the acoustic emission(AE) signal due to surface cracking and moisture movement in the flat-sawn boards of oak(Quercus Variablilis) during drying using the principal component analysis(PCA) and artificial neural network(ANN). To reduce the multicollinearity among AE parameters such as peak amplitude, ring-down count event duration, ring-down count divided by event duration, energy, rise time, and peak amplitude divided by rise time and to extract the significant AE parameters, correlation analysis was performed. Over 96 of the variance of AE parameters could be accounted for by the first and second principal components. An ANN analysis was successfully used to classify the Af signals into two patterns. The ANN classifier based on PCA appeared to be a promising tool to classify the AE signals from wood drying.

• Journal of the Korea Society for Simulation
• /
• v.21 no.4
• /
• pp.91-102
• /
• 2012

Network port scan attack is the method for finding ports opening in a local network. Most existing IDSs(intrusion detection system) record the number of packets sent to a system per unit time. If port scan count from a source IP address is higher than certain threshold, it is regarded as a port scan attack. The degree of risk about source IP address performing network port scan attack depends on attack count recorded by IDS. However, the measurement of risk based on the attack count may reduce port scan detection rates due to the increased false negative for slow port scan. This paper proposes a method of summarizing 4 types of information to differentiate network port scan attack more precisely and comprehensively. To integrate the riskiness, we present a risk index that quantifies the risk of port scan attack by using PCA. The proposed detection method using risk index shows superior performance than Snort for the detection of network port scan.

• Biomedical Science Letters
• /
• v.13 no.1
• /
• pp.11-15
• /
• 2007

We examined the effects of pregnancy and pregnancy-induced hypertension (PIH) on platelet activation. Thirty-six women with PIH (blood pressure > 140/90 mm Hg after two consecutive measurements after the $24^{th}$ weeks of gestation) without proteinuria, fifty-six normotensive pregnant women, and fifty non-pregnant women were studied. WBC, RBC, platelet related variables, including mean platelet component (MPC), mean platelet volume (MPV) and platelet component distribution width (PCDW) were determined for this study. MPC levels were significantly lower in women with PIH compared with normotensive pregnant women and non-pregnant women (P<0.05). MPC levels were inversely con-elated with PIH (r=-0.49, P<0.001), systolic BP (r=-0.22, P<0.01), diastolic BP (r=-0.17, P<0.005), WBC (r=-0.30, P<0.001), MPV (r=-0.41, P<0.001), and PCDW (r=-0.68, P<0.001), and positively con-elated with RBC (r=0.32, P<0.001), platelet count (r=0.21, P<0.05), and mean platelet mass (MPM) (r=0.18, P<0.05). MPC levels were found to be an independent factor associated with PIH and PCDW (P<0.01) after adjustments were made for potential confounding factors such as gestational age, systolic blood pressure, diastolic blood pressure, WBC, RBC, Platelet count, and PCDW. In conclusion, MPC levels were significantly lower in women with PIH, and MPC levels were found to be an independent factor associated with PIH and PCDW. Therefore, platelet activation is suggested as a useful predictor for patients with PIH.

• Journal of the East Asian Society of Dietary Life
• /
• v.10 no.5
• /
• pp.419-424
• /
• 2000

To develop a functional Kimchi utilizing onion, 5 different Kimchi with onion used as a major ingredient were formulated. The changes in pH. titratable acidity, reducing sugar. total bacterial count, and the number of lactic acid bacteria in the process of fermentation were studied A. onion Kimchi Control. B : onion Kimchi added with oyster, C : onion Kimchi added with salted shrimp, D : onion Kimchi added with oyster, cucumber, and a bit of radish, E : onion Kimchi added with salted shrimp, cucumber, and a bit of radish. pH of onion Kimchi decreased during storage, but titratable acidity increased. The pH values of onion Kimchi were not significantly different among groups, the changes in pH during fermentation were the lowest in A, and changes in B and D were lower than those of C and E. Salt concentration tended to decrease during the fermentation process, and the changes in salt concentration were lower in D and E than in B and C. Reducing sugar content maximized at 4 days of fermentation and decreased after 12 days. The number of lactic acid bacteria increased during first 4 days of fermentation and decreased after 12 days. Total lactic acid bacterial count were the most lowest in A.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.6
• /
• pp.133-140
• /
• 1999

In this study, a monitoring method to detect chip disposal state in drilling system based on neural network was proposed and its performance was evaluated. If chip flow is bad during drilling, not only the static component but also the fluctuation of dynamic component of drilling. Drilling torque is indirectly measured by sensing spindle motor power through a AC spindle motor drive system. Spindle motor power being measured drilling, four quantities such as variance/mean, mean absolute deviation, gradient, event count were calculated as feature vectors and then presented to the neural network to make a decision on chip disposal state. The selected features are sensitive to the change of chip disposal state but comparatively insensitive to the change of drilling condition. The 3 layerd neural network with error back propagation algorithm has been used. Experimental results show that the proposed monitoring system can successfully recognize the chip disposal state over a wide range of drilling condition even though it is trained under a certain drilling condition.

• The Korean Journal of Applied Statistics
• /
• v.32 no.6
• /
• pp.837-849
• /
• 2019

Latent class models (LCM) are useful tools to draw hidden information from categorical data. This model can also be interpreted as a mixture model with multinomial component distributions. In some cases, however, an available dataset may contain both categorical and count or continuous data. For such cases, we can extend the LCM to a mixture model with both multinomial and other component distributions such as normal and Poisson distributions. In this paper, we consider a LCM for the data containing categorical and count data to analyze the Drug Review dataset which contains categorical responses and text review. From this data analysis, we show that we can obtain more specific hidden inforamtion than those from the LCM only with categorical responses.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.5
• /
• pp.495-500
• /
• 2014

We examined chemical changes in oysters Crassostrea gigas and packing water that were sold after storage at 5, 10, and $20^{\circ}C$. The pH of oysters stored at $5^{\circ}C$ dropped to 5.81 after 10 days of storage, while that of oysters at $10^{\circ}C$ and $20^{\circ}C$ dropped to 5.37 after 8 days and to 5.04 after 4 days, respectively. The glycogen content of oysters stored at $5^{\circ}C$ decreased from 718.89 to 421.85 mg/100g during storage, while that of oysters at $10^{\circ}C$ decreased to 351.49 mg/100 g after 4 days. The turbidity and soluble protein in packing water increased slightly. The viable cell count of oysters did not exceed 6 log CFU/g after 10 days of storage at $5^{\circ}C$, but that of oysters at $10^{\circ}C$ did so after 8 days. Additionally, the viable cell count of packing water was lower than that of oysters. We performed a principal component analysis, where the first principal component (55.03%-57.24%) and second principal component (42.76%-44.97%) described most variation. The first principal component included the pH of oysters and packing water, and the glycogen content of oysters. A Pearson correlation between the first two principal components had a higher R value than that between other components. Freshness was evaluated using the pH of oysters and packing water, and glycogen. We found that soluble protein content was significantly associated with a lower pH and glycogen content.

• Clinical and Experimental Pediatrics
• /
• v.48 no.5
• /
• pp.461-468
• /
• 2005

The major function of immune system is to protect infections. The immune systems are composed of innate and adaptive immunity. In adaptive immunity, the cellular and humoral components interact each other. Neonates and infants are infected frequently, because immune systems are naive and easy to expose to infectious agents. The complete history and physical examination is essential to evaluate the child with recurrent infections. The environmental risk factors of recurrent infections are day care center, cigarette smoke, and air pollution. The underlying diseases such as immunodeficiency, autoimmune diseases, allergy, and disorders of anatomy or physiology increase the susceptibility to infections. In immunodeficiency, infections are characterized by severe, chronic, recurrent, and unusual microbial agents infection. The defects of antibody production are susceptible to sinopulmonary bacterial infections. T cells defects are vulerable to numerous organisms such as virus, fungi, bacteria and etc. The screening tests for immune functions are the quantitative and qualitative measurements of each immune components. A complete blood count with white blood cell, differential, and platelet provide quantitative informations of immune components. Total complement and immunoglobulin levels represent the humoral component. Antibody levels of previously injected vaccines also provide informations of the antigen specific antibody immune responses. T cell and subsets count is quantitative measurement of cell mediated immunity. Delayed hypersensitivity skin test is a crude measurement of T cell function. The long term outcome of children with recurrent infections is completely dependent on the underlying diseases, the initial time of diagnosis and therapy, continued management, and genetic counscelling.