• Journal of Power Electronics
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• v.17 no.1
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• pp.282-293
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• 2017

There exists a strong coupling between real and reactive power owing to the complex impedances in droop based islanded microgrids (MGs). The existing virtual impedance methods consider improvements of the impedance matching for sharing of the voltage controlled power (VCP) (reactive power for Q-V droop, and real power for P-V droop), which yields a 1-DOF (degree of freedom) tunable virtual impedance. However, a weak impedance matching for sharing of the frequency controlled power (FCP) (real power for $P-{\omega}$ droop, and reactive power for $Q-{\omega}$ droop) may result in FCP overshoots and even oscillations during load transients. This in turn results in VCP oscillations due to the strong coupling. In this paper, a 2-DOF tunable adaptive virtual impedance method considering impedance matching for both real and reactive power (IM-PQ) is proposed to improve the power sharing performance of MGs. The dynamic response is promoted by suppressing the coupled power oscillations and power overshoots while realizing accurate power sharing. In addition, the proposed power sharing controller has a better parametric adaptability. The stability and dynamic performances are analyzed with a small-signal state-space model. Simulation and experimental results are presented to investigate the validity of the proposed scheme.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.283-287
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• 1996

This paper described the estimator and eliminator far three kinds of artifacts in electrocardiogram. The most efficient estimation of baseline drift could be obtain in the cubic spline interpolation method with the PQ and TP segment which are considered to be isoelectric, from the experimental results obtained from the applied 4 types of algorithms. The time loss and distortion could be avoided with the aid of detection criteria by checking if baseline drifts exist or not. The AIEF proposed in this paper was verified as having the best removal performance with less distortion in the QRS complex through the comparison of 5 proposed algorithms. furthermore, the AIEF are most suitable far the ECG analyzer which was only needed relatively short time data due to the fast conversion into the stable state. The proposed parabolic filter with 11 points width was identified as having the best performance for the elimination of muscle artifacts. Also we could obtain 99.7% detection accuracy of spike component and minimize the error identifying QRS complex as spike.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.293-300
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• 2021

This study presents a Power Quality(:PQ) costs calculation methodology based on Value-Based Methodology. A SCDF including Voltage Sag Costs is presented to calculate Sustained Interruption Costs, Momentary Interruption Costs, and Voltage Sags Costs. Authors compared between interruption costs without Back-Up Power Supply and interruption costs with Back-Up Power Supply, and showed reduction of interruption costs by investing Back-UP Power Supply by multi-lateral analyzation. By applying this method to the real system, evaluated and analyzed power quality of the system.

• Korean Journal of Mathematics
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• v.30 no.1
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• pp.67-72
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• 2022

For a locus with two alleles (I^A and I^B), the frequencies of the alleles are represented by $$p=f(I^A)={\frac{2N_{AA}+N_{AB}}{2N},\;q=f(I^B)={\frac{2N_{BB}+N_{AB}}{2N}$$ where N_AA, N_AB and N_BB are the numbers of I^AI^A, I^AI^B and I^BI^B respectively and N is the total number of populations. The frequencies of the genotypes expected are calculated by using p², 2pq and q². Choi showed the method of whether some genotypes is in these probabalities. Also he calculate the probability generating function for offspring number of genotype under a diploid model( [1]). In this paper, let x(t, p) be the probability that I^A become fixed in the population by time t-th generation, given that its initial frequency at time t = 0 is p. We find adapted equations for x using the mean change of frequence of alleles and fitness of genotype. Also we apply this adapted equations to several diploid model and it also will apply to actual examples.

• The Journal of Korean Society for Radiation Therapy
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• v.13 no.1
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• pp.38-46
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• 2001

Purpose : The aim of this study is to investigate the effect of tissue inhomogeneities when appling to contrast medium among Homogeneous, Batho and ETAR dose calculation method in RTP system. Method and Material : We made customized heterogeneous phantom it filled with water or contrast medium slab. Phantom scan data have taken PQ 5000 (CT scanner, Marconi, USA) and then dose was calculated in 3D RTP (AcQ-Plan, Marconi, USA) depends on dose calculation algorithm (Homogeneous, Batho, ETAR). The dose comparisons were described in terms of 2D isodose distribution, percent depth dose data, effective path length and monitor unit. Also dose distributions were calculated with homogeneous and inhomogeneous correction algorithm, Batho and ETAR, in each patients with different clinical sites. Results : Result indicated that Batho and ETAR method gave rise to percent depth dose deviation $1.5{\sim}2.7\%,\;2.3{\sim}3.5\%$ (6MV, field size $10{\times}10cm^2$) in each status with and without contrast medium. Also show that effective path lengths were more increase in contrast status (23.14 cm) than Non-contrast (22.07 cm) about $4.9\%$ or 10.7 mm (In case Hounsfield Unit 270) and these results were similary showned in each patient with different clinical site that was lung. prostate, liver and brain region. Concliusion : In conclusion we shown that the use of inhomogeneity correction algorithm for dose calculation in status of injected contrast medium can not represent exact dose at GTV region. These results mean that patients will be more irradiated photon beam during radiation therapy.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.355-369
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• 2015

Purpose: This study aimed to identify on the attitudes toward the life support care among elderly people using Q methodology. Methods: Thirty-nine elderly people classified 34 selected Q statements into a shape of normal distribution using a 9 point scale. The obtained data were analyzed by using a PQ Method PC program. Results: Principal component analysis identified 4 types of the attitudes toward the life support care among elderly people. Type I is "Situational & Self-determination linear type", type II is "Destiny & Life support care denied type", type III is "Avoidant & Family decision emphasis type" and type IV is "Respect for life & life support care approved type". Most of elderly people have been attitude that wish to receive honor their own decisions toward the prolongation treatment. Conclusion: The findings indicate a need to policy guidelines and public information that express self-determination of elderly people.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.240-247
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• 2020

Purpose: This study aimed to employ a Q-methodological approach that can understand the characteristics of each type according to the subjective structures of humans, to help understand type-specific characteristics and to provide a basis for creating the image of dental technicians among dental technology students based on the characteristics of each type. Methods: The Q-methodology was used for this study. 120 Q-statements were obtained from a qualitative survey of 120 students of the department of dental technology. To select the Q-sample, the Q-population was categorized by taking several repeated readings. The selected statements were reviewed and revised by experts and 33 Q-samples were finally selected. The data were then analyzed using the PQ method program. Results: Among 42 P specimens, 22 were classified into type 1, 9 types 2, and 11 types 3. "Type 1" recognizes the image of dental technicians positively and optimistically (Z=1.29) (Z=1.74), but it is named "self-development oriented" in the sense that steady self-development must be underpinned (Z=1.37). "Type 2" agreed strongly that they could work for a lifetime without age or gender discrimination (Z=2.09). This type was referred to as "professional-oriented" because the recognition of dental technicians is more focused on "professional." "Type 3" was tagged "pride-oriented," showing the strongest agreement that they can be proud of their job as healthcare workers (Z=1.08). Conclusion: Many studies on such an image should be carried out to determine the importance of occupational images and establish desirable status for dental technicians to continue developing.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.113-122
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• 2007

Purpose: We proposed the method using dose-volume Histogram index to compare prospective plan trials in tomotherapy planning optimization. Materials and Methods: For 3 patients in cranial region, thorax and abdominal region, we acquired computed tomography images with PQ 5000 in each case. Then we delineated target structure and normal organ contour with pinnacle Ver 7.6c, after transferred each data to tomotherapy planning system (hi-art system Ver 2.0), we optimized 3 plan trials in each case that used differ from beam width, pitch, importance. We analyzed 3 plan trials in each region with isodose distribution, dose-volume histogram and dose statistics. Also we verified 3 plan trials with specialized DVH-indexes that is dose homogeneity index in target organ, conformity index around target structure and dose gradient index in non-target structures. Results: We compared with the similarity of results that the one is decide the best plan trial using isodose distribution, dose volume histogram and dose statistics, and the another is using DVH-indexes. They all decided the same plan trial to better result in each case. Conclusion: In some of case, it was appeared a little difference of results that used to DVH-index for comparison of plan trial in tomotherapy by special goal in it. But because DVH-index represented both dose distribution in target structure and high dose risk about normal tissue, it will be reasonable method for comparison of many plan trials before the tomotherapy treatments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.157-164
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• 2011

It is very difficult problem to factorize composite number. Integer factorization algorithms, for the most part, find ($a,b$) that is congruence of squares ($a^2{\equiv}b^2$(mode $n$)) with using factoring(factor base, B) and get the result, $p=GCD(a-b,n)$, $q=GCD(a+b,n)$ with taking the greatest common divisor of Euclid based on the formula $a^2-b^2=(a-b)(a+b)$. The efficiency of these algorithms hangs on finding ($a,b$). Fermat's algorithm that is base of congruence of squares finds $a^2-b^2=n$. This paper proposes the method to find $a^2-b^2=kn$, ($k=1,2,{\cdots}$). It is supposed $b_1$=0 or 5 to be surely, and b is a double number. First, the proposed method decides $k$ by getting kn that satisfies $b_1=0$ and $b_1=5$ about $n_2n_1$. Second, it decides $a_2a_1$ that satisfies $a^2-b^2=kn$. Third, it figures out ($a,b$) from $a^2-b^2=kn$ about $a_2a_1$ as deciding $\sqrt{kn}$ < $a$ < $\sqrt{(k+1)n}$ that is in $kn$ < $a^2$ < $(k+1)n$. The proposed algorithm is much more effective in comparison with the conventional Fermat algorithm.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.383-389
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• 2002

We experienced a case of partial DiGeorge syndrome in a $35^{＋5}$ week premature female infant presented with micrognathia, fish-shaped mouth, beaked nose, nasal regurgitation, obstructive sleep apnea, velopharyngeal insufficiency and late onset hypocalcemic seizures. The chromosome 22q11 microdeletion was found by the FISH method. The lab findings showed serum calcium level of 4.4 mg/dL, ionized calcium level of 0.49 mg/dL, phosphorous level of 7.5 mg/dL, magnesium level of 1.3 mg/dL and PTH-RIA level of <1 pq/mL. Initial treatment was done with 10% calcium gluconate infusion and magnesium sulfate followed by oral calcium gluconate and low phosphorousformula milk feeding. The serum calcium level was normalized in 6 days. Nasal regurgitation, desaturation with obstructive sleep apnea continued. T-cell functions & numbers(CD 3, CD 4, CD 8)were decreased but Ig G/A/M levels were normal. No visible signs of thymus shadow were seen in either chest X-ray & chest MRI. Electrocardiography and echocardiography showed normal heart. Kidney ultrasonographby showed right side mild hydronephrosis. Neurosonography was normal but EEG showed electrical partial seizure. Hearing assessment by BERA showed mild to moderate hearing impairment. Velopharyngoplasty is scheduled for further treatment. A brief review of literature was made.