• Journal of Trauma and Injury
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• v.25 no.3
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• pp.79-86
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• 2012

Purpose: The most common cuase of transfusion for trauma victims in an emergency department is hypovolemic shock due to injury. After an injury to an internal organ of the chest or the abdomen, transfusion is needed to supply blood products and to compensate tissue oxygen transport and bleeding. From the 1990's, there have been some reports that transfusion is one of the major factors causing multiple-organ failure. Thus, as much as possible, tranfusion has been minimized in the clinical setting. This study aims to analyze the prognostic factors for mortality among trauma victims transfused with blood products in an emergency department. Methods: We conducted this study for the year of 2010 retrospectively. The study group included adult trauma victims tranfused with blood products in our ED. The exclusion criteria were discharge against medical advice, and missing follow-up due to transfer to another facility. During the study period, 34 adult trauma victims were enrolled. We compared the clinical variables between survivors and non-survivors. Results: the mean age of the 34 victims was 58.06 years, and males account for 58.5% of the study group. The most-frequently used form transportation was ambulance(119, 55.9%), and the most common injury mechanism was mobile vehicle accidents(67.6%). The mean revised trauma score (RTS) was 5.9, and the mean injury severity score (ISS) was 47.76. The mortality rate in the ED was 58.5%, Comparison of survivors with non-survivors showed statistical differences in injury mechanism, initial SBP, DBP, RTS, ISS, and some laboratory data such as AST, ALT, pH, PO2, HCO3, glucose (p<0.05). Regression analyses showed that mortality among adult trauma victims transfused in the ED correlated with RTS. Conclusion: When an adult trauma victim is transported to the ED and needs a tranfusion, the emergency physician carefully assess the victim by using physiologic data.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.886-890
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• 1999

From previous studies, there is a strong possibility in buffaloes that the marked increase in blood volume (BV) under hot conditions contributes to heat transportation from the rectum to the skin. The present study was done to clarify changes with environmental temperature on water-shift between blood and extracellular fluid (ECF), heat distribution between the rectum and the skin, and blood flow rates (BFR) at the hind legs (reflecting the skin surface). Four buffaloes and four Friesian cows were successively exposed to three different temperatures of $20^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$. BV and ECF volume were measured with Evans' blue and sodium-thiocyanate dilution methods, respectively. Rectal and subcutaneous (as the skin) temperatures were measured by copper-constantan thermocouples. BFR were measured by a supersonic blood flow meter. With an increase in environmental temperature, skin temperature in buffaloes increased significantly than cows, but rectal temperature was not significantly different between two species. BV, especially plasma compartment, increased significantly in only buffaloes, while ECF volume did not change in both species. BFR increased significantly in buffaloes, but not in cows. From these results, the increased of BV may be caused by water flowing from ECF compartment. The water-shift may induce the increase of BFR and skin temperature. It is suggested in the present study that internal changes of blood compartment in buffaloes contribute to transfer of heat to the skin surface.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.577-582
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• 2015

This paper is the fundamental study for the application of cold storage system to the transportation equipment by sea and land. This numerical study presents the solid-liquid phase change phenomenon of calcium chloride solution of 30wt %. The governing equations are 1-dimensional unsteady state heat transfer equations of $1^{st}$ order partial differential equations. This type of latent heat storage material is often usable in fishery vessel for controlling the temperature of container with constant condition. The governing equation was discretized with finite difference method and the program was composed with Mathcad program. The main parameters of this solution were the initial temperature of heat storage material, ambient temperature of cold air and the velocity of cold air. The data of boundary layer thickness becomes thin with the increasing of cold air flowing velocity and also the heat storage completion time become shorten.

• The Journal of Korean Society for School & Community Health Education
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• v.22 no.1
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• pp.1-9
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• 2021

Objective: This study examines the prevalence of osteoporosis, and compares with activity of daily living(ADL), instrumental activity of daily living(IADL) and health-related quality of life(QoL) among the elderly people with disabilities. Methods: This study analyzed the data of 3,113 persons with disabilities over 65 years of age who responded to the questionnaire using data from the National Survey of People with Disabilities in 2017 on the people with disabilities (PWD). Descriptive statistics, X2-test, and independent sample t-test were conducted using the SPSS win 21.0 program. Results: The prevalence of osteoporosis in the elderly PWD was 18.7%. There were significant differences in sex, age, type of disability, and disability severity according to the presence or absence of osteoporosis (p<0.05). Walking and Transfer of ADL were related to osteoporosis in elderly PWD. Financial management and Transportation use of IADL were related to osteoporosis (p<0.05). The PWD with osteoporosis were analyzed to have lower health-related quality of life compared to the disabled elderly without osteoporosis (p<0.05). Conclusion: Based on the results of this study, a strategy for developing a program for managing osteoporosis. Strengthening health management in the elderly PWD is required.

• International Journal of Computer Science & Network Security
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• v.23 no.6
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• pp.27-34
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• 2023

This paper proposed an Inter-Carrier-Interference (ICI) Canceling Orthogonal Frequency Division Multiplexing (OFDM) receiver for 5G mobile system to support 500 km/h linear motor high speed terrestrial transportation service. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceler is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number 𝒏 to receiver sub-carrier number 𝒍 is generated. In case of 𝒏≠𝒍, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 2 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, for modulation schemes below 16QAM, we confirmed that the difference between BER in a 2 path reverse Doppler shift environment and stationary environment at a moving speed of 500 km/h was very small when the number of taps in the multi-tap equalizer was set to 31 taps or more. We also confirmed that the BER performance in high-speed mobile communications for multi-level modulation schemes above 64QAM is dramatically improved by the use of a multi-tap equalizer.

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.96-100
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• 2007

Purpose: Trauma is the 5th most common leading cause of death in Korea, but there has been no appropriate management system for patients until now. We analyzed the main causes of death in trauma patients by comparing the characteristics of those patients with the characteristics of patients who survived. We feel this analysis should have a positive effect on the development of an appropriate trauma management system in Korea. Methods: We retrospectively reviewed trauma patients who had been admitted to the Department of General Surgery from February 2002 to February 2007. We compared several expected risk factors between the mortality and the survival group. Data on the transportation, arrival time at the emergency center, amount of transfusion, initial shock index, cause of death, and initial physical condition according to RTS (Revised trauma score), ISS (Injury severity score) and TRISS (Trauma and Injury Severity Score) were collected. Patients with ISS lower than 12 were excluded. Results: Three hundred sixty-six(366) patients with multiple injuries were included. There were 40 patients in the mortality group and 326 patients in the survival group. The mean arrival time (minutes) to emergency center was longer in the mortality group (137.6 vs 93.6 p 0.04). The total amount of transfusion (ml) was larger in the mortality group (7139 vs 2470 p 0.01). The initial shock index was higher in the mortality group (1.45 vs 1.17 p<0.01). The RTS, ISS, and TRISS were not statistically different between the groups. In the multivariate analysis, mean arrival time and initial shock index were important factors for survival. Conclusion: If the mortality rate of trauma patients is to be reduced, the arrival time at the emergency center should be minimized. Improvement of the emergency medical transfer service system is very important for achieving that.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.535-543
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• 2022

A CPFD (Computational particle fluid dynamics) model of solar fluidized bed receiver of silicon carbide (SiC: average d_p=123 ㎛) particles was established, and the model was verified by comparing the simulation and experimental results to analyze the effect of particle behavior on the performance of the receiver. The relationship between the heat-absorbing performance and the particles behavior in the receiver was analyzed by simulating their behavior near bed surface, which is difficult to access experimentally. The CPFD simulation results showed good agreement with the experimental values on the solids holdup and its standard deviation under experimental condition in bed and freeboard regions. The local solid holdups near the bed surface, where particles primarily absorb solar heat energy and transfer it to the inside of the bed, showed a non-uniform distribution with a relatively low value at the center related with the bubble behavior in the bed. The local solid holdup increased the axial and radial non-uniformity in the freeboard region with the gas velocity, which explains well that the increase in the RSD (Relative standard deviation) of pressure drop across the freeboard region is responsible for the loss of solar energy reflected by the entrained particles in the particle receiver. The simulation results of local gas and particle velocities with gas velocity confirmed that the local particle behavior in the fluidized bed are closely related to the bubble behavior characterized by the properties of the Geldart B particles. The temperature difference of the fluidizing gas passing through the receiver per irradiance (∆T/I_DNI) was highly correlated with the RSD of the pressure drop across the bed surface and the freeboard regions. The CPFD simulation results can be used to improve the performance of the particle receiver through local particle behavior analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.777-784
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• 2017

Energy harvesting through a thermoelectric module normally makes use of the temperature gradient in the system's operational environment. Therefore, it is difficult to obtain the desired output power when the system is subjected to an environment in which a low temperature gradient is generated across the module, because the power generation efficiency of the thermoelectric device is not optimized. The utilization of solar energy, which is a form of renewable energy abundant in nature, has mostly been limited to photovoltaic solar cells and solar thermal energy generation. However, photovoltaic power generation is capable of utilizing only a narrow wavelength band from the sunlight and, thus, the power generation efficiency might be lowered by light scattering. In the case of solar thermal energy generation, the system usually requires large-scale facilities. In this study, a simple and small size thermoelectric power generation system with a solar concentrator was designed to create a large temperature gradient for enhanced performance. A solar tracking system was used to concentrate the solar thermal energy during the experiments and a liquid circulating chiller was installed to maintain a large temperature gradient in order to avoid heat transfer to the bottom of the thermoelectric module. Then, the setup was tested through a series of experiments and the performance of the system was analyzed for the purpose of evaluating its feasibility and validity.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.727-735
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• 2016

Smart transformers are effective at reducing the weight and increasing the efficiency of traction systems for railroad applications. A smart transformer generally consists of rectifier modules and the Dual-Active-Bridge (DAB) converter modules. The efficiency of the smart transformer depends on not only the electrical characteristics, but also on the control method of the converter modules. Especially, a DAB converter has a high order degree of freedom of voltage modulation to control the power transferred through the high frequency transformer, and a voltage modulation method, are very critical for the efficiency of the DAB converter. This paper proposes a new voltage modulation method for the DAB converter to increase the efficiency in the low/medium power transfer condition. The proposed modulation method controls the reactive power in the high frequency transformer, making it zero. And, the switching loss is dramatically reduced by using the received converter module as a diode rectifier. The feasibility of the proposed modulation method is verified by computer simulation of the 900Vdc DAB converter power control.