• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.767-773
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• 2017

Printed Circuit Heat Exchanger (PCHE) has an advantage for exchanging thermal energy between high-pressure and high-temperature fluids because its core is made by diffusion bonding method of accumulated metal thin-plates which are engraved of flow channel. Moreover, because it is possible that the flow channel can be micro-size hydraulic diameter, the heat transfer area per unit volume can be made larger than traditional heat exchanger. Therefore, PCHE can have higher efficiency of heat transfer. The smaller channel size can make the larger heat transfer area per unit volume. But if high pressure fluid flows inside the channel, the channel wall can be deformed, the structure and shape of flow channel and header have to be designed appropriately. In this study, the design methodology of PCHE channel in high pressure environment based on pressure vessel codes was investigated. And this methodology was validated by computational analysis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.4
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• pp.390-402
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• 2011

A preliminary study on species composition of a Korean purse seine catch landed at cannery was conducted in April 2011. In the cannery, all tuna catch are sliding through a sorting grid panel that filters and drops fish in the buckets by size class (above 9kg, 3.4-9kg, 1.8-3.4kg, 1.4-1.8kg and below 1.4kg). In cannery processing, species sorting was made for skipjack tuna and yellowfin tuna only from catches greater than 3.4kg during filtering but not for bigeye tuna because of difficulties in species identification between bigeye tuna and yellowfin tuna under frozen state. As no species identification was carried out for catch groups less than 3.4kg in the cannery process, this study focused on sorting out skipjack tuna and yellowfin tuna from these groups and then identifying bigeye tuna from all size groups of yellowfin tuna. Using the mixture rate of species obtained from the samples taken, species composition of the landed catch was estimated. As results, cannery research showed 95% for skipjack tuna, 3% for yellowfin tuna and 2% for bigeye tuna in species composition, while vessel logbook data represented 96%, 3% and 1% for skipjack tuna, yellowfin tuna and bigeye tuna, respectively. The proportion of bigeye tuna identified in the cannery was slightly higher than shown in logbook data by 1%.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.139-148
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• 2020

The most important factor affecting the berthing energy generated when a ship berths is the berthing velocity. Thus, an accident may occur if the berthing velocity is extremely high. Several ship features influence the determination of the berthing velocity. However, previous studies have mostly focused on the size of the vessel. Therefore, the aim of this study is to analyze various features that influence berthing velocity and determine their respective importance. The data used in the analysis was based on the berthing velocity of a ship on a jetty in Korea. Using the collected data, machine learning classification algorithms were compared and analyzed, such as decision tree, random forest, logistic regression, and perceptron. As an algorithm evaluation method, indexes according to the confusion matrix were used. Consequently, perceptron demonstrated the best performance, and the feature importance was in the following order: DWT, jetty number, and state. Hence, when berthing a ship, the berthing velocity should be determined in consideration of various features, such as the size of the ship, position of the jetty, and loading condition of the cargo.

• Radiation Oncology Journal
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• v.5 no.1
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• pp.1-11
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• 1987

Total 390 mice were irradiated with $2{\times}3cm$ abdominal field and $200{\times}5/wk$ regimen with orthovoltage x-ray machine. All animals were divided into 2 large groups, damage and recovery, and histopathologic changes were analyzed at various total dose level (1,000 cCy-5,000 cCy) and intervals (1 week-15 weeks). Almost acute changes such as decreased mitotic activity, villi shortening and focal erosion of mucosa recovered within 1-2 weeks in 1,000-3,000 cGy irradiated group but mild changes persisted in 4,000 and 5,000 cCy irradiated groups. Chronic delayed changes such as thickening of vessel wall with focal thrombosis, submucosal fibrosis, mucosal atrophy and chronic ulcer were observed from 2-3 week specimens in 4,000 and 5,000 cGy groups, These late changes recovered slightly, as increasing time intervals after irradiation but mild, persistant changes were observed throught all follow up period. These data suggest hat even 4,000 cCy is not completely safe for possible permanent damage and judicious modificiation of total dose, dose rate, fraction size, and field size should be considered for better results.

• Journal of Gastric Cancer
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• v.1 no.1
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• pp.32-37
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• 2001

Purpose: Three subgroups of stage II stomach cancer (T1N2M0, T2N1M0, T3N0M0) by UICC-TNM staging system show obvious survival difference to each other, which becomes the pitfall of the current staging system. We analyzed the survival and relapse pattern of stage II stomach cancer patients in three subgroups retrospectively to prove the need for change in staging system. Materials and Methods: From July 1989 to December 1995, curative gastric resection was performed in 1,037 patients with gastric adenocarcinoma, and among them 268 patients ($26\%$) were in stage II. The number in each of subgroups (T1N2M0, T2N1M0, and T3N0M0) were 17, 139 and 112 respectively. Survival and relapse pattern were analyzed and median follow up period was 46 months. Results: The 3-year cumulative survival rates of T1N2M0, T2N1M0, and T3N0M0 were $50\%,\;80\%,\;and\;76\%$ respectively (p=0.001). And the 3-year cumulative survival rates of T1N2M0 was comparable to those of 2 subgroups of stage IIIa (T2N2M0, T3N1M0), $47\%\;and\;45\%$ (p>0.05). Peritoneal recurrence was the most frequent in T3N0M0. And hematogenous spread was more frequent in T2N1M0 while nodal spread was more frequent in T1N2M0. Ten out of 17 cases of T1N2M0 died of recurrence. Most of them showed submucosal tumor with depressed lesion and mean tumor size was 3.3 cm. Conclusions: Up-staging of T1N2M0 should be considered because it has the lowest survival rate and the worst prognosis among the three subgroups of Stage II stomach cancer patients. In early gastric cancer patients with high-risk factors (large tumor size, invasion into the submucosal layer, and lymphatic vessel involvement), lymph node dissection and postoperative adjuvant therapy is recommended in an attempt to prevent recurrence in the form of lymph node metastasis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.709-716
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• 2018

In 2017, there was an accident in which a cadet onboard training was killed. This cadet worked 12 hours a day. No regulation has yet been laid down to define hours and breaks for interns. Therefore, the purpose of this study is to investigate the working status of commissioned training, the satisfaction survey of commissioned training, and to improve the treatment of commissioned trainees. The survey was conducted on students commissioned from merchant vessels, and 461 respondents answered the questionnaire. The results of the survey are as follows. First, 43.0 % of cadets said that they worked 10 hours a day on average, regardless of the vessel type, and 35.2 % said that the average rest time was 8 hours. 15.6 % of respondents said they had worked more than 12 hours. Unreasonable order cases deviating from the purpose of education were "making ramen, working at rest time, instruction of dangerous work, making night snack and private errands." Second, the satisfaction level of cadets who practiced on LNG carriers was high, while the satisfaction level of cadets on bulk carriers and container carriers was low. It was confirmed that the ship's size, ship's age, working hours, rest time and training support costs had little minor effect on educational satisfaction. Lastly, 56.8 % of the cadets answered 'commissioned training is like work.' Based on the results of the questionnaires, we proposed the following improvement methods; providing legislation for working hours and rest time for commissioned training cadets, protection system against violence and sexual harassment and victim protection. This study focuses on the working and rest time of merchant ship's cadet and it is meaningful to investigated the onboard training satisfaction by ship's type, size and age.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6905-6911
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• 2013

Background: Breast cancer (BC) is the top cancer among women worldwide and the most frequent malignancy among Iranian women over the past few decades. The increasing trend and high mortality rate of BC in the developing world necessitates studies concentrating on its characteristics in countries in Asia. The current study focused on clinical and histopathological features of BC among Iranian females. Materials and Methods: This retrospective study involved 714 Iranian patients with histopathologically proven BC undergoing resection of primary tumours and axillary clearance. Demographic, clinical and histopathological data were obtained and studied between ten year age groups (${\leq}40$ years, 41-50 years, 51-60 years, 61-70 years, and ${\leq}71$ years) in four chronologic phases from 1994-2009. Results: Mean age of patients was $49.4{\pm}13.1$ years. Most of cases (33.2%) were in 41-50 group. Mean size of primary tumors was $3.94{\pm}2.47$ cm and 87.1% of cases had infiltrative ductal carcinoma. Modified radical mastectomy was the most common method of surgery carried out (48.8%). Some 57.1% of tumors were in pT2 and tumor size decreased significantly during the period (p<0.05). The most common BC stage was llla (27%). Lower BC stages (0 and 1) constituted 13.9% of the diagnosed tumors. Our series of patients aged ${\leq}40$ had larger tumors (mean $4.73{\pm}3.02$ cm) compared to older age groups (p=0.003). Lower stages (0 and I) were more frequent among the oldest patients while nearly 50% of patients aged ${\leq}40$ had tumor stage III. We also observed a significant decreasing trend in the mean LN count (p<0.05) and blood vessel invasion (p=0.023) from younger to older age groups. Conclusions: More aggressive disease for younger age groups, earlier peak incidence age and high rate of advanced BC at the time of diagnosis among Iranian women, were the main findings of this study.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.450-457
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• 2019

Sedimentation is a common problem for river ports. But its intensity depends on the rate of sedimentation, channel shape and size, hydrodynamic behavior of the river and the importance of the port. High sedimentation rate in Yangon River has become one major issue for Myanmar as her largest port is located on the Yangon riverbank. As a result of the high sedimentation rate, shallow water area near the confluence of Yangon River, Pazundaung Creek, and Bago River keeps blocking the navigation channel to the Yangon Port, which also limits the size of vessel calling to Yangon Port. Therefore, studies to understand sediment transport process in Yangon River are required because the economic development of Myanmar highly relies on the Yangon Port. This paper aims to calculate the sediment transport and to predict the riverbed elevation changes in Yangon River by using Bagnold (1966) theory. Calculation result shows that huge difference can be found in the bed load transport between the rainy season and dry season in Yangon River, and thus the sedimentation problem would become more severe in the dry season when the transported sediments are reduced. The estimated sedimentation rate in dry season indicates that the rate of riverbed level rise near the Yangon Port area is about 0.063 m per year, which would lead to approximately 3.15 m rise in the riverbed level in next 50 yrs, considering the same workload of dredging to maintain the navigation channel.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5721-5727
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• 2014

Objectives: To evaluate the performance of clustering methods used in the prognostic assessment of categorical clinical data for hepatocellular carcinoma (HCC) patients in China, and establish a predictable prognostic nomogram for clinical decisions. Materials and Methods: A total of 332 newly diagnosed HCC patients treated with hepatic resection during 2006-2009 were enrolled. Patients were regularly followed up at outpatient clinics. Clustering methods including the Average linkage, k-modes, fuzzy k-modes, PAM, CLARA, protocluster, and ROCK were compared by Monte Carlo simulation, and the optimal method was applied to investigate the clustering pattern of the indices including platelet count, platelet/lymphocyte ratio (PLR) and serum aspartate aminotransferase activity/platelet count ratio index (APRI). Then the clustering variable, age group, tumor size, number of tumor and vascular invasion were studied in a multivariable Cox regression model. A prognostic nomogram was constructed for clinical decisions. Results: The ROCK was best in both the overlapping and non-overlapping cases performed to assess the prognostic value of platelet-based indices. Patients with categorical platelet-based indices significantly split across two clusters, and those with high values, had a high risk of HCC recurrence (hazard ratio [HR] 1.42, 95% CI 1.09-1.86; p<0.01). Tumor size, number of tumor and blood vessel invasion were also associated with high risk of HCC recurrence (all p< 0.01). The nomogram well predicted HCC patient survival at 3 and 5 years. Conclusions: A cluster of platelet-based indices combined with other clinical covariates could be used for prognosis evaluation in HCC.

• Journal of Chest Surgery
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• v.33 no.9
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• pp.716-722
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• 2000

Background: Modified Blalock-Taussig shunt using 3mm or 3.5mm PTFE graft has been performed in patients with small body weight or in candidates for single ventricle palliation. However, there are few reports concerning clinical outcomes in terms of pulmonary artery growth and shunt patency rate after shunt operations using such a small graft. Material and Method: Twenty-five patients rate after shunt operations using 3 or 3.5 mm sized grafts from September 1996 to August 1999. We retrospectively assessed the pulmonary artery growth and the shunt patency rate by reviewing the pre-and post-operative pulmonary angiograms. The risk factors for late death and second shunt operations were also analyzed. To assess the presence of any correlation between body weight and selection of the graft size, regression analysis was done in 81 cases of shunt operations performed during the same period. Result: There were 1(4%) early death and 5(20%) late deaths. The survivors were followed up for an average of 7.34 months. The pulmonary artery index increased significantly from 129$\pm$66$\textrm{mm}^2$/$m^2$ to 213$\pm$114 $\textrm{mm}^2$/$m^2$(p=0.002). The shunt patency rate assessed at postoperative 2, 4, 6 and 8 months were 82.5%, 77%, 73% and 42% respectively with a marked decline between 6 and 8 months. Asplenia was a frequent finding for the patients with late death although the incidence failed to reach statistical significance(p=0.078). Pre-operative diagnosis of PA with VSD was found to be a statistically significant risk factor for a second shunt operation(p=0.01). Body weight(a) at operation and graft size(b) used in the shunt operations revealed strong correlation and could be expressed by the following formula; b=0.128a + 3.233. Conclusion: Adequate growth of pulmonary artery and satisfactory early patency rate could be obtained by modified Blalock-Taussing shunt using 3mm or 3.5mm graft. However, during 6 to 8 months after shunt operations, the patency rate fell sharply, which implicates that close observation and early intervention are mandatory in this period.