• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.214-224
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• 2024

Valves play an essential role in a chemical plant such as regulating fluid flow and pressure. Therefore, optimal selection of the valve size and type is essential task. Valve size and type have been selected based on theoretical formulas about calculating valve sizing coefficient (Cv). However, this approach has limitations such as requiring expert knowledge and consuming substantial time and costs. Herein, this study developed a model for predicting valve sizes and types using machine learning. We developed models using four algorithms: ANN, Random Forest, XGBoost, and Catboost and model performances were evaluated using NRMSE & R² score for size prediction and F1 score for type prediction. Additionally, a case study was conducted to explore the impact of phases on valve selection, using four datasets: total fluids, liquids, gases, and steam. As a result of the study, for valve size prediction, total fluid, liquid, and gas dataset demonstrated the best performance with Catboost (Based on R², total: 0.99216, liquid: 0.98602, gas: 0.99300. Based on NRMSE, total: 0.04072, liquid: 0.04886, gas: 0.03619) and steam dataset showed the best performance with RandomForest (R²: 0.99028, NRMSE: 0.03493). For valve type prediction, Catboost outperformed all datasets with the highest F1 scores (total: 0.95766, liquids: 0.96264, gases: 0.95770, steam: 1.0000). In Engineering Procurement Construction industry, the proposed fluid-specific machine learning-based model is expected to guide the selection of suitable valves based on given process conditions and facilitate faster decision-making.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.4
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• pp.311-318
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• 2010

U. S. NRC Regulation Guide 1.52 regulating ESF ACS in nuclear power plants has been revised to revision 3. To apply reduction of operability test time, allowance of alternative challenge agents for in-place leak test of HEPA filters, and upgrade of Methyl Iodide penetration acceptance criterion in activated carbon performance test suggested in Reg. Guide 1.52(Rev.3) on Yonggwang units 5 and 6 ESF ACSes, technical feasibility study was carried out with on-site experiments as well as experiments with a lab-scale model. It was confirmed that the moisture in the system returned to the level before the test in 1 or 4 days even though the moisture was removed during the operability test lasting more than 10 hours. Therefore, it is appropriate to perform monthly operability test in 15 minutes just long enough to check the operability of equipment. To change challenge material for in-place HEPA filter leak test, size of aerosol, production rate, and leak detection capability were compared for DOP and PAO. It was concluded that PAO can be substituted for DOP in nuclear power plants. The upgrade of Methyl Iodide penetration acceptance criterion from 0.175 % to 0.5 % in active carbon filter bed deeper than 4 inches was to conform to the change of activated carbon performance test method to ASTM D3803(1989). It was confirmed that Methyl Iodide penetration acceptance criterion of 0.5 % under $30^{\circ}C$, relative humidity 95 % condition was conservatively good enough for testing performance of active carbon insitu. The licence change of Yonggwang units 5 and 6 has been completed based on this study.

• Journal of the Korean Wood Science and Technology
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• v.18 no.3
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• pp.53-68
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• 1990

This research has been executed for maximization of lumber yield and more efficient use of small diameter logs. Sample logs from thinnings carne from densed artificial stands at the Kwangnung Experimental Forests situated in the central region of Korean peninsula. Species of sample logs were obtained to execute sawing and strength test for larch, and lumber strength test in full size for pitch pine and Korean pine. A survey on sawmills consuming domestic logs was carried out to know sawmill production, costs and utilization structure of lumber as a guide to business analysis. Results showed that sawing pattern from small logs less than 15cm in diameter was necessary to cut 9cm by 9cm square per one log in order to obtain high lumber recovery and provide for wide market needs. The total lumber yield of squares plus side boards was 56 percent to 58 percent from small logs and the yield for log sweep in 30 percent decreased by 24.5 percent in sawing production, compared to yield for straight logs. In sawing efficiency, production of lumber by twin band saw could be improved 238 percent higher than lumber of the same species produced by conventional sawmilling methods, and sawing accuracy with twin band saw was much higher at the lumber production than band saw. Lumber from the small larch logs has shown 70 knots per $m^2$ on its faces and also lumber showed lots of face checkings by air drying on the yard, compared to other species. MOR in bending of lumber in full size from small logs of larch was found ranging from 380kg/$cm^2$ to 460kg/$cm^2$, resulting in 40 percent less than the strength from clear small specimens. In lumber containing knots, cross grain, etc, longitudinal stress wave speed was delayed about 48 percent by defects in lumber from both larch and pitch pine logs. The surveyed sample sawmills consumed the domestic logs at the rate of 54 percent to 84 percent in the total timber consumption, showing high consumption at mills located in the mountains.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.4989-4992
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• 2012

Purpose: Guide-wire localization (GWL) has been a standard technique for many years. Excision of nonpalpable malignant breast lesions with clear surgical margins reduces the risk of undergoing re-excision. The objective of the present study was to evaluate the efficacy of GWL biopsy for assessing surgical margins. Methods: This retrospective study concerned 53 patients who underwent GWL biopsy for non-palpable breast lesions and breast carcinoma diagnosed by histological examination. Age of the patients, tumour size, radiographic findings, breast density specifications, specimen volumes, menopausal status and family history of the patients and surgical margin status were recorded. Results: Median age was 53.3 years, median tumour size was 1.5 cm and median specimen volume was $71.5cm^3$. In fifteen patients (28%) DCIS and in 38 patients (72%) invasive ductal carcinoma was diagnosed. There was positive surgical margins in twenty eight (52.8%) patients. The median distance to the nearest surgical margin was 7.2 mm in clear surgical margins. Younger age and denser breast specifications were found as statistically significant factors for surgical margin status. Median age of the patients who had positive margins was 49.4 years where it was 56.9 years in the patients with negative margins (p=0.04). 79% of the patients with positive margins had type 3-4 pattern breast density according to BIRADS classification as compared to 48% in the patients who had negative margins (p=0.03). Some 38 patients who had positive or close surgical margins received re-excision (72%). Conclusion: Positive margin rates may be higher because of inherent biological differences and diffuse growth patterns in younger patients. There are also technical difficulties that are relevant to denser fibroglandular tissue in placing hooked wire. High re-excision rates must be taken into consideration while performing GWL biopsy in non-palpable breast lesions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.1-10
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• 1992

In the already presented paper, the performance analysis of SMUX was need a lot of time bacause of recussive method, So this paper proposed the new mathematical method for the SMUX's performance. And it is constructed and analyzed the queueing model for SMUX based on the Go-back N retransmission ARQ model. It is assumed that it has the infinite buffer and a single server. It is analzied the parameters that have influence on the byffer and a single server. It is analzied the parameters that have influence on the buffer behaviour of statistical multiplexer overflow probabilities. maximum buffer size. mean wating time and mean buffer size, and these relationship are represented the graphs and datas which provided a guide to the buffer design problem. As these results. it is efficient when the SMUX is apphed that the traffic density is below 0.5 and transmission error probabilities is below 10­$^3$. So this paper can be applied to the basic and theoretical background prior to the implementation of SMUX.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3080-3086
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• 2009

We have analyzed the output characteristics of a LGP with pyramid shaped pattern by using a 3-D simulation tool. The influences on the LGP output of various parameters such as the pattern shape, pattern occupation ratio, pattern size, and etching angle were investigated. Comparing the pyramid shaped pattern with hemispherical patterns, little difference was observed. And, it was proved that the pattern occupation ratio and etching angle have relatively large effects on LGP output characteristics, while the pattern size has no effect. Therefore, we can improve the LGP characteristics by optimizing pattern structure and distribution.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.2
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• pp.167-180
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• 2011

The portraits created in the age of Queen Elizabeth I show a very exquisite description about the ruff collar and cuffs representing the notable evolution of periodical costumes from a detailed viewpoint. This thesis analyzes the ruff collar and cuffs of the portraits of Queen Elizabeth I. The method used selects 32 pieces from the portraits of Queen Elizabeth I that are considered excellent depictions of a ruff collar and cuffs, to investigate size, form and decorations. Conclusively, the ruff collar tends to be extremely enlarged and thickened (coinciding with the development of glue) while the cuffs denote the aspect of double cuffs coupled with the turn-back cuffs without a change in size. These traits were widely shown from 1585 to 1587, while after 1588 the ruff cuffs completely disappeared in the portraits of Elizabeth I. At the same time, the change of a ruff collar was remarkable, the collar being in the erect position behind the head (with the use of supporters), of a consistent thickness and decoration of elaborate lace. During the transition period from the $16^{th}$ century to the $17^{th}$ century the earliest change was in cuffs followed by collars. This research is a helpful guide to detect the relatively exact date of portraits not definitively identified in the latter part of the $16^{th}$ century and to observe the microscopic evolution of costumes in the latter part of the $16^{th}$ century.

• Journal of Information Science Theory and Practice
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• v.4 no.2
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• pp.34-52
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• 2016

This study was designed to investigate organizational culture and emotional intelligence as predictors of job performance among library personnel in Edo state, Nigeria. The survey research design was employed for the study with a population size of 181 library personnel in the 15 academic libraries under study, and due to the manageable population size, total enumeration was adopted as the sampling technique. The questionnaire was used to elicit data from the respondents. Of the 181 copies of the questionnaire administered, 163 copies were retrieved and found valid for analysis constituting a 90% response rate. Four research questions and four null hypotheses (tested at 0.05 level of significance) were formulated to guide the study. The tool used to analyze the research question was descriptive statistics (percentage, mean, and standard deviation) and inferential statistics (correlation and multiple regression) for testing the hypotheses. The findings of the study revealed that there is a high level of job performance, good organizational culture, and high level of emotional intelligence among the personnel. Organizational culture and emotional intelligence jointly and significantly predict job performance of personnel. There is significant positive correlation between organizational culture and job performance. The linear combination of emotional intelligence and organizational culture predict job performance of library personnel in the academic libraries under study. The research concludes that there is a need for high job performance in libraries which is predicted by the organizational culture of the library and the level of emotional intelligence of the library personnel.

• Korean Journal of Community Nutrition
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• v.11 no.6
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• pp.740-749
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• 2006

The objective of this study was to develop nutrition education materials for older adults, 'nutritional management for healthy aging'. A booklet and four leaflets were developed based on lesson plans. Topics of the lesson plans included eating habit assessment. Korean food guide pyramid, meal planning, eating sensibly and weight management. The titles of the leaflets were 'Eating right for healthy aging', 'Eat calcium-rich foods', 'Enjoy fruits & vegetables' and 'Weight management'. Illustrations and icons appropriate to the texts were designed using illustrator 9.0 and Photoshop 6.0. Booklet (letter size, 5 chapters, 44 pages) and leaflets (B4 size, 6 sections) focused on modifying undesirable eating habits, providing practical tips for desirable behaviors, and behavioral modification such as recording in a food diary, goal setting and increasing self-efficacy. The drafts were pilot-tested by interviews with older adults(n=10), and minor changes were made. The characteristics of revised materials are as follows; i) materials focused on providing desirable eating behaviors for healthy aging, ii) messages were simple and specific, iii) large fonts(13 pt) were used and materials included interesting pictures and illustrations, iv) materials provided tips for balanced diets and recipes fur older adults, v) materials included sections for participation of learners including assessment of nutritional risk factors and obesity, meal planning and games. The revised materials are self-explanatory and can be used by older adults and in nutrition education for older adults.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3619-3626
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• 2015

The coal shed at thermal power plant(T.P.P) is the biggest building on size among nuclear, coal and other power plant industry buildings. This the coal shed of indoor type is mass volume, the size of 6 soccer fields and 73 meter in height. Structural and functional elements take priority over aesthetic factors. The shed is built to make mighty space for structural safety and functional store by using the concrete, $75,000m^3$ on the total of central retaining wall and sub buttress, and the steel frame used by 11,744-ton P.E.B. system. The design requirement on its wall and frame, P.E.B. system's feature, and specific data of main process followed by construction are inquired. The aim of this study is to suggest the design requirement and guide for the indoor type of the coal shed.