• 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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.189-200
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• 2019

Korean seafarers have played a key role throughout the country's history and economic development. They have been a major source of foreign remittance into the nation as well as a pivotal sector in emergency logistics during war times. However, the current number of Korean seafarers in decreasing due to low job attractiveness and retention rate onboard. This is a major problem for the national and international shipping industry as youth seem not to be interested in working onboard for long periods of time. The purpose of this study is to 1) determine what the public opinion about seafarers in Korea is and 2) find out what factors mostly stand out in the public opinion about seafarers profession. The paper suggests that three main types of opinion groups emerged. The first type is labeled as 'high risk, high workload and high stress' as respondents recognized a high possibility of accident onboard and, at the same time, acknowledged that seafarers can be fatigued and stressed. The second type was named as 'Dangerous, Dirty, Difficult', as seafarers' image was mainly associated to fishing vessels and not to merchant and passenger ships. The third type recognized that the social position of the seafarers was low due to 'low social recognition'. The study suggests that all three types have a negative image of seafarers' job. Based on the results of this study, it is necessary to establish various policies and marketing tools to improve the negative job image linked to seafarers by the public opinion. If the public image of seafarers can be improved and attractiveness rose, it is expected a higher number of seafarers will pursue and keep a career at sea.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.41-52
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• 2002

Purpose : 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. Materials and Methods : The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were peformed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. Results : The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probabiliy. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values $(4\~5\%\;increased)$ for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased $(50\~70\%\;increased)$ for upon extending PTV margins by 2.0 cm. Conclusion : Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.