• Proceedings of the KSME Conference
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• 2003.04a
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• pp.456-461
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• 2003

A fuel cell is an electrochemical device in which the energy of a chemical reaction is converted directly into electricity. By combining hydrogen fuel with oxygen from air, electricity is formed, without combustion of any form. Water and heat are the only by-products when hydrogen is used as the fuel source. Fuel cell stack consists of multi-layered unit cells. A unit cell consists of MEA and bipolar plates. The end plate of fuel cell stack should give a uniform distributed pressure to multi unit cell layers so as to reduce the contact resistance and to prevent the leakage of reactant gases and the damage of multi layer components. The current end plate is redundantly large and heavy. It makes the power per unit volume reduced. Topology optimization of end plate is conducted for mass reduction and enhancement of bending rigidity. The evaluation of the current design and the recommendation for the future design is remarked.

• International Journal of Automotive Technology
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• v.4 no.2
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• pp.57-64
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• 2003

The Intelligent Power Unit (IPU) utilized in Honda's Civic Hybrid Integrated Motor Assist (IMA) system was developed with the aim of making every component lighter, more compact and more efficient than those in the former model. To reduce energy loss, inverter efficiency was increased by fine patterning of the Insulated Gate Bipolar Transistor (IGBT) chips, 12V DC-DC converter efficiency was increased by utilizing soft-switching, and the internal resistance of the IMA battery was lowered by modifying the electrodes and the current collecting structure. These improvements reduced the amount of heat generated by the unit components and made it possible to combine the previously separated Power Control Unit (PCU) and battery cooling systems into a single system. Consolidation of these two cooling circuits into one has reduced the volume of the newly developed IPU by 42% compared to the former model.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.410-418
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• 1999

This paper describes the use of residual and parameter identification methods for fault detection in an air handling unit. Faults can be detected by comparing expected condition with the measured faulty data using residuals. Faults can also be detected by examining unmeasurable parameter changes in a model of a controlled system using a system identification technique. In this study, AutoRegressive Moving Average with seXtrnal input(ARMAX) and AutoRegressive with eXternal input(ARX) models with both single-input/single-input and multi-input/single-input structures are examined. Model parameters are determined using the Kalman filter recursive identification method. Regression equations are calculated from normal experimental data and are used to compute expected operating variables. These approaches are tested using experimental data from a laboratory's variable-air-volume air-handling-unit.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.583-595
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• 2010

Virtual water is defined as the volume of water to produce commodities and provide services, which has been developed by Tony Allan since the early 1990s. This research aims to evaluate a volume of virtual water trade in Korea from 1998 to 2007 by applying the evaluation method of unit virtual water volume to agricultural, live stock and industrial products, which is developed by Chapagain and Hoekstra (2004). Also, the concept of water footprint is deployed to quantify the volume of virtual water trade between countries. The study attempts to assess the appropriateness of the evaluation method of unit virtual water volume by employing the method to calculate the total amount of agricultural products in Korea and comparing this with the amount of agricultural water demand in the Korea Water Vision 2006. The research outcome shows that Korea has a net virtual water import of 32 billion $m^3$ on average in the form of agricultural, live stock and industrial commodities whose volume gradually increases. The gap between the volume of virtual water import of agricultural and live stock commodities and the total volume of agricultural water use reaches approximately 600 million $m^3$. This figure can be negligible considering the total volume of water demand in Korea, around 16 billion $m^3$, which demonstrates the validity of the evaluation method in terms of analyzing water balance.

• Journal of Korean Home Economics Education Association
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• v.26 no.3
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• pp.91-112
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• 2014

The purpose of this study is to analyze how the elements of activating happiness education suggested by Noddings is reflected in the Home Economics part of Middle School Technology-Home Economics Textbook Volume 2 of 2009 Curriculum Revision. The introduction style of unit, sub-unit, and small chapter, the objectives, the body contents, the activity resources, the tables/diagrams/pictures, the supplementry and advancedl materials, and the wrap-up and evaluation of sub-unit and units of Home Economics part of Technology Home Economics textbook volume 2 were analyzed. Noddings suggested the elements for activating happiness education in five areas of personal life sector including 'home making', 'place and nature', 'parenting', 'chracter and spiriual experiences', and 'growth of interpersonal relationships' and two areas of public one including 'preperation for work' and 'community, democracy and voluntary activities'. The specific elements in seven sectors of activating happiness education were extracted using the content analysis. How the elements of those suggested by Noddings were reflected in the various parts of the textbook were analyzed in terms of the closeness of approaches, contents, and procedures between Noddings's and textbook. The major findings of this study were as follows: 1. The degree to which the elements of activating happiness education were reflected in the textbook differed by each unit. The elements of activating happiness education were reflected the most frequently in the unit of 'Unit of Practice of Eco-friendly Family Life' and the least frequently in the unit of 'Unit of Career and Life Planning'. 2. The Home Economics units of Technology Home Economics textbooks 1&2 reflects the factors of personal life and public life that Noddings suggested for activating happiness. However, personal life-related factors are relatively more reflected in the units than the public life-related factors. 3. Although the elements of activating happiness education were generally reflected in all the elements of a textbook, these elements were relatively more reflected in the Unit Introduction, Sub-unit Introduction, Chapter and Introduction, Objectives, body contents and tables/diagrams/pictures.

• Journal of radiological science and technology
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• v.46 no.3
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• pp.239-246
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• 2023

In this study, we assessed the effect of reduction of tumor volume in the head and neck cancer by using RANDO phantom in Static Intensity-Modulated Radiation Therapy (S-IMRT) and Volumetric-Modulated Arc Therapy (VMAT) planning. RANDO phantom's body and protruding volumes were delineated by using Contour menu of Eclipse™ (Varian Medical System, Inc., Version 15.6, USA) treatment planning system. Inner margins of 2 mm to 10 mm from protruding volumes of the reference were applied to generate the parameters of reduced volume. In addition, target volume and Organ at Risk (OAR) volumes were delineated. S-IMRT plan and VMAT plan were designed in reference. These plans were assigned in the reduced volumes and dose was calculated in reduced volumes using preset Monitor unit (MU). Dose Volume Histogram (DVH) was generated to evaluate treatment planning. Conformity Index (CI) and R² in reference S-IMRT were 0.983 and 0.015, respectively. There was no significant relationship between CI and the reduced volume. Homogeneity Index (HI) and R² were 0.092 and 0.960, respectively. The HI increased when volume reduced. In reference VMAT, CI and R² were 0.992 and 0.259, respectively. There was no relationship between the volume reduction and CI. On the other hand, HI and R² were 0.078 and 0.895, respectively. The value of HI increased when the volume reduced. There was significant difference (p<0.05) between parameters (D_mean and D_max) of normal organs of S-IMRT and VMAT except brain stem. Volume reduction affected the CI, HI and OAR dose. In the future, additional studies are necessary to incorporate the reduction of the volume in the clinical setting.

• Magazine of the Korean Society of Agricultural Engineers
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• v.8 no.1
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• pp.1011-1034
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• 1966

This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.101-107
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• 1989

To evaluate disposition characteristics of procainamide and its active metabolite, N-acetylprocainamide (NAPA), cross-over study for procainamide and NAPA was performed in 5 male adult dogs. After single administration of 10 mg/kg procainamide over 15 minutes, the range of measured plasma NAPA concentrations during experimental period were 0.03 to 0.124 ug/ml and early 'dip' phenomenon was distinct on NAPA concentration to time curve in all 5 dogs. Volume of distribution (Vss) and central compartment volume (Vc) of procainamide were $1.20{\pm}0.27\;L/kg$ of body weight and $0.36{\pm}0.08\;L/kg$, respectively. Vss and Vc of NAPA were $1.21{\pm}0.21\;L/kg$ and $0.26{\pm}0.07\;L/kg$, respectively. Intercompartmental clearance (Clint) of procainamide was 3.44 L/kg/hr and that of NAPA was 1.62 L/kg/hr. Total body clearance (Cl) of procainamide and NAPA were $0.47{\pm}0.08$ and $0.35{\pm}0.08\;L/kg/hr$. The half-life $(t_{1/2{\beta}})$ of procainamide and NAPA were 2.85 hrs and 2.77 hrs, respectively. Metabolic clearance (Clm)of procainamide by N-acetylation was $18.24{\pm}6.22\;ml/kg/hr$, which corresponded to 3.9% of total procainamide clearance.

• Industrial Engineering and Management Systems
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• v.9 no.2
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• pp.107-120
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• 2010

In today's uncertain economic environment, the evaluation of safety for investment alternatives is of practical importance in manufacturing companies. This paper examines a method of quantitatively evaluating profitability and risk for multiple alternatives using the total-cost unit-cost domain. The paper assumes such factors as unit sales price, sales and production volume, unit variable cost, fixed cost, and yield for each alternative. The paper incorporates the relationship between production capacity and demand, distinguishing between cases of production capacity surplus and shortage for each year over the entire planning horizon. The paper investigates the case in which the values of each factor independently move in the direction of decreasing profit each year, and clarifies the procedure of comparing safety among multiple investment alternatives on a single consolidated total-cost unit-cost domain. The difficulty of the problem lies in the method of consolidating multiple total-cost unit-cost domains into a single domain since the combination of years of capacity surplus and shortage depends upon the change values in each factor under consideration. A systematic method of evaluating profitability as well as risk is presented, and the validity of the proposed method is verified using a numerical example.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.5
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• pp.1153-1166
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• 2024

The calculation of the waste landfill unit price at the S landfill located in I city was analyzed in two cases: Method A by statistical techniques and Method B by reflecting policy variables such as the prohibition of direct landfilling of household waste and the right to emit greenhouse gases. As a result, in the case of method B, the landfill unit price increased by 34.1% to 57.6% depending on the type of waste compared to method A. By landfill unit price composition, landfill work cost, operation and management cost, greenhouse gas emission rights transaction cost, and resident support fund increased by 61.0%, 68.3%, 63.5%, and 34.1% to 57.6%, respectively. Therefore, considering the characteristics of the landfill, which requires more than 30 years of mid- to long-term operation and management even after the end of the landfill, policy variables should be identified periodically for stable landfill operation and management. In addition, periodic activities to calculate the landfill unit cost are considered necessary, such as predicting the amount of landfill waste and deriving additional future cost factors such as greenhouse gas emission rights.