• International Journal of Naval Architecture and Ocean Engineering
• /
• v.8 no.5
• /
• pp.442-455
• /
• 2016

The resistance and seakeeping performance of a high-speed monohull vessel were investigated through a series of model tests in a towing tank. The hull had a slender wave-piercing bow, round bilge, and small deadrise angle on stern. Tests on the bare hull in calm water were first conducted and tests on spray rails followed. The spray rails were designed to control the flow direction and induce a hydrodynamic lift force on the hull bottom to reduce trim angle and increase rise of the hull. The maximum trim of the bare hull was $4.65^{\circ}$ at the designed speed, but the spray rails at optimum location reduced trim by $0.97^{\circ}$. The ship motion in head seas was examined after the calm water tests. Attaching the rails on the optimum location effectively reduced the pitch and heave motion responses. The vertical acceleration at the fore perpendicular reduced by 11.3%. The effective power in full scale was extrapolated from the model test results and it was revealed that the spray rails did not have any negative effects on the resistance performance of the hull, while they effectively stabilized the vessel in calm water and waves.

• Journal of Korea Port Economic Association
• /
• v.23 no.4
• /
• pp.159-175
• /
• 2007

The purpose of this study is to examine the causal relationship between trading volume of freight and industrial growth in Korea ports, and to induce policy implications. In order to test whether time series data is stationary and the model is fitness or not, we put in operation unit root test, cointegration test. And we apply Granger causality based on an error correction model, Hsiao(1981) method and variance decomposition. The results indicate that the extent of causality between trading volume of freight and industrial growth is strong in order of Incheon port, Busan port, Gwang Yang port, Ulsan port. We can infer policy suggestions as follows; The port policy of government must be focused on re-adjusting investment among Korea ports and raising competitive power of Korea ports

• Journal of Haehwa Medicine
• /
• v.22 no.2
• /
• pp.57-66
• /
• 2014

Objectives : Features of military medicine and war pattern at the time Methods : "Haeng Gun Bang Pyeon Pyeon Bang", military medicine literature, that allows pattern of ancient war to be inferred was considered. First, background of this literature formation was examined, and the contents included were arranged based on table of contents. Lastly, pattern of war at the time and role of military medicine were studied through the meaning of times and medicine in this book. Results : This book was written by Naseyo(羅世瑤, of an unidentifiable period), an intellectual of Qing Period(淸代) in the 2nd year of Emperor Xianfeng(咸豊 2, 1852). It was composed of total 3 volumes and a book, and 684 prescriptions were written under 6 large sections(大門). Conclusions : This book was written in the middle of spirit of the times of national prosperity and military power caused by defeat in the Opium War and popular publication in a series, an academic current of the times. Though there were many treatments about external wound in this book, thoughts of armed forces and combat by people of the time were reflected, including drying method(乾法) making portable foods, drinking control method(戒酒法) to resolve drinking(飮酒) problem in the armed forces, treatment method of infectious disease, information collection method from enemy troops by confession, and various treatments for diseases of military horse. It is expected that this book will be good material for studies in the field of military medicine and used as material for diverse combination studies such as history and military science.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2007.11a
• /
• pp.193-198
• /
• 2007

KIER has been developing the anode supported flat tubular SOFC stack for the intermediate temperature $(700{\sim}800^{\circ}C)$ operation. for this purpose, we have first fabricated anode supported flat tubular cells by the optimization between the current collecting method and the induction brazing process. After that we designed the compact fuel & air manifold by adopting the simulation technique to uniformly supply fuel & air gas and the unique seal & insulation method to make the more compact stack. For making stack, the prepared anode-supported flat tubular cells with effective electrode area of $90cm^2$ of connected in series with 12 modules, in which one module consists of two cells connected in parallel. The performance of stack in 3 % humidified $H_2$ and air at $800^{\circ}C$ shows maximum power of 507 W. Through these experiments, we obtained basic & advanced technology of the anode-supported flat tubular cell and established the proprietary concept of the anode-supported flat tubular SOFC stack in KIER.

• Journal of Environmental Impact Assessment
• /
• v.24 no.4
• /
• pp.367-374
• /
• 2015

To examine the effect of thermal discharge from nuclear power plants, Sea Surface Temperature (SST) is one of the most important variables measured by satellite remote sensing. However, the study was not much comparison of field data and satellite SST from operational Landsat 8 Thermal Infrared Sensor(TIRS) and Landsat 7 ETM+. The Landsat 8 TIRS have 2 spilt Thermal Infrared channels but ETM+ uses one channel for extracting of SST. In spite of that this research carried out that Landsat 7 ETM+ have more profitable for correction of SST than Landsat 8 TIRS. The used 15 Landsat 7 and 8 Thermal Infrared data of path/row 114-36 were processed by SST algorithm of ENVI and IDL. The in-situ SST data from KHOA(Korea Hydrographic and Oceanographic Administration) compared with satellite SST and the accuracy of extracted SST were assessed by each field sites in-situ point data with time series satellite SST.

• Journal of KSNVE
• /
• v.6 no.2
• /
• pp.163-177
• /
• 1996

An investigation on thermohydraulic stability of flow oscillations in the CANada Deuterium Uranium-600(CANDU-6) heat transport system has been conducted. Flow oscillations in reactor coolant loops, comprising two heat sources and two heat sinks in series, are possibly caused by the response of the pressure to extraction of fluid in two-phase region. This response consists of two contributions, one arising from mass and another from enthalpy change in the two-phase region. The system computer code used in the investigation os SOPHT, which is capable of simulating steady states as well as transients with varying boundary conditions. The model was derived by linearizing and solving one-dimensional, homogeneous single- and two-phase flow conservation equations. The mass, energy and momentum equations with boundary conditions are set up throughout the system in matrix form based on a node-link structure. Loop stability was studied under full power conditions with interconnecting the two compressible two phase regions in the figure-of-eight circuit. The dominant function of the interconnecting pipe is the transfer of mass between the two-phase regions. Parametric survey of loop stability characteristics, i. e., damping ratio and period, has been made as a function of geometrical parameters of the interconnection line such as diameter, length, height and orifice flow coefficient. The stability characteristics with interconnection line has been clarified to provide a simple criterion to be used as a guide in scaling of the pipe.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.12
• /
• pp.1678-1687
• /
• 2013

This paper describes a prototype of 3-phase 3.3kV/220V 6kVA modular semiconductor transformer developed in the lab for feasibility study. The developed prototype is composed of three single-phase units coupled in Y-connection. Each single-phase unit with a rating of 1.9kV/127V 2kVA consists of a high-voltage high-frequency resonant AC-DC converter, a low-voltage hybrid-switching DC-DC converter, and a low-voltage hybrid-switching DC-AC converter. Also each single-phase unit has two DSP controllers to control converter operation and to acquire monitoring data. Monitoring system was developed based on LabView by using CAN communication link between the DSP controller and PC. Through various experimental analyses it was verified that the prototype operates with proper performance under normal and sag condition. The system efficiency can be improved by adopting optimal design and replacing the IGBT switch with the SiC MOSFET switch. The developed prototype confirms a possibility to build a commercial high-voltage high-power semiconductor transformer by increasing the number of series-connected converter modules in high-voltage side and improving the performance of switching element.

• Journal of the Korean Society of Safety
• /
• v.21 no.5 s.77
• /
• pp.28-33
• /
• 2006

The rapidly advanced industrial society takes advantage of high-technology, but it also suffered from the side effects such as various diseases by contamination. Of these problems, air pollution is considered as the most important problem nowadays. Air contamination is not only limited outdoors, but it also causes more serious effect in our indoor air environment. Depending on the notion that indoor air effects physical health seriously, the needs of the air cleaner is more earnest. Therefore, the main purpose of this study is to develop the air cleaner to meet the standard and get rid of poisonous and harmful material from the atmosphere by using a Corona Discharge. According to the purpose of this study, We set the negative ion generator, the UV, $TiO_{2}$ optical catalyzer, the electrical dust collector and the air filter in series order. It emits a lot of negative ions. We use these ions to purify harmful factors and contaminated materials. We collect the dust using static power that comes from the discharge of corona. At the same time, we try to develop the air cleaner to keep the air quality to meet the standard and kill the various viruses using UV LED and $TiO_{2}$ optical catalyzer. In this study, we use the UV LED that is smaller and efficient than a existing UV lamp. What is more, the UV LED has a features that a stabilizer occupying much space is not needed any more.

• Genomics & Informatics
• /
• v.6 no.1
• /
• pp.36-43
• /
• 2008

Radiotherapy would be the choice of treatment for human cancers, because of high cost-effectiveness. However, a certain population of patients shows a resistance to radiotherapy and recurrence. In an effort to increase the efficacy of radiotherapy, many efforts were driven to find the genes causing the unresponsiveness to ionizing radiation. In this paper, we compared the gene expression profiles of two lung cancer cell lines, H460 and H1299, which showed differential responses to ionizing radiations. Each cell were irradiated at 2 Gy, and harvested after 0, 2, 4, 8, 12 and 24 hours to examine the expressions. Two-way ANOVA analysis on time-series experiments of two cells could select 2863 genes differentially expressed upon ionizing radiation among 32,321 genes in microarray (p<0.05). We classified these genes into 21 clusters by SOM clustering according to the interaction between cell types and time. Two SOM clusters were enriched with apoptosis-related genes in pathway analysis. One cluster contained higher levels of phosphatidyl inositol 3-phosphate kinase (PI3K) subunits in H1299, radio-resistant cells than H460, radiosensitive cells. TRAIL receptors were expressed in H460 cells while the decoy receptor for TRAIL was expressed in H1299 cells. From these results, we could characterize the differential responsiveness to ionizing radiation according to their differential expressions of apoptosis-related genes, which might be the candidates to increase the power of radiotherapy.

• Structural Engineering and Mechanics
• /
• v.65 no.4
• /
• pp.453-464
• /
• 2018

In this paper, an efficient higher-order shear deformation theory is presented to analyze thermomechanical bending of temperature-dependent functionally graded (FG) plates resting on an elastic foundation. Further simplifying supposition are made to the conventional HSDT so that the number of unknowns is reduced, significantly facilitating engineering analysis. These theory account for hyperbolic distributions of the transverse shear strains and satisfy the zero traction boundary conditions on the surfaces of the plate without using shear correction factors. Power law material properties and linear steady-state thermal loads are assumed to be graded along the thickness. Nonlinear thermal conditions are imposed at the upper and lower surface for simply supported FG plates. Equations of motion are derived from the principle of virtual displacements. Analytical solutions for the thermomechanical bending analysis are obtained based on Fourier series that satisfy the boundary conditions (Navier's method). Non-dimensional results are compared for temperature-dependent FG plates and validated with those of other shear deformation theories. Numerical investigation is conducted to show the effect of material composition, plate geometry, and temperature field on the thermomechanical bending characteristics. It can be concluded that the present theory is not only accurate but also simple in predicting the thermomechanical bending responses of temperature-dependent FG plates.