• The Journal of Engineering Research
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• v.1 no.1
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• pp.23-30
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• 1997

Energy transfer by free convection arises in many engineering applications, such as a hot steam radiator for heating a room, refrigeration coils, electric transformers, heating elements and electronic equipments. Generally unsteady natural convection flow in a horizontal channel with arbitrary wall temperatures and the mathematical and physical basis of convection transport has been considered in general. A physically meaningful exact solution of the problem has been obtained in a closed form by the application of the standard finite sine transform technique. Influences of the governing parameters, the Prandtl number and the Rayleigh number, to bring the flow and heat transfer to final steady states have been discussed separately. For constant values of the arbitray wall temperatures and of the function, determining the average axial velocity, the final steady state is approached in different times respectively for the cases when the Prandtl number Pr>1 and Pr<1. It is also seen that the function, representing the axial temperature gradient, is influenced by none of the governing parameters : but the steady state flow is influenced only by the Rayleigh number. There are, of course, many applications. Free convection strongly influences heat transfer from pipes and transmission lines, as well as from various electronic devices. It is also relevant to the environmental sciences, where it is responsible for oceanic and atmospheric motions, as well as related heat transfer processes.

• The Korean Journal of Emergency Medical Services
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• v.13 no.3
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• pp.29-40
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• 2009

Objective : This study is an experimental study which is designed to examine the differences between knowledge and self-confidence before and after theory education(CPR PPT material) based on guidelines of CPR and emergency cardiac treatment of American Heart Association(AHA, 2005) and video self-instruction program for the general public by Korean Association of Cardiopulmonary Resuscitation(KACPR), trace CPR performance ability after CPR and AED education and investigate the accuracy of artificial respiration and chest compression, and know the difference in CPR performance abilities including AED. Methods : Subjects of this study include ground crews and staffs at M airport in G province equipped with emergency equipments for CPR according to Art. 47, Sec. 2 of Emergency Medical Law, airport police, rent-a-cops, security guard, quarantine officer, custom officer, and communication, electricity, civil engineering, facility management staff, airport fire fighting staff, air mechanic, traffic controller, and airport management team among airport facility management staffs. They were given explanation of necessity of research and 147 of 220 subjects who gave consent to this research but 73 who were absent from survey were excluded were used as subjects of this study. of 147 subjects, there were 102 men and 45 women. Results : 1) Knowledge score of CPR was $6.18{\pm}0.87$ before instruction and it was increased to $15.12{\pm}1.78$ after instruction, and there was statistically significant difference. 2) Self-confidence score in CPR was $3.16{\pm}0.96$ before instruction and it was increased to $7.05{\pm}0.75$ after instruction, and there was statistically significant difference. 3) Total average score in CPR performance ability after instruction was 7.46 out of 9, performance ability was highest in confirmation of response as 144(97.95%), follwed by request of help as 140(95.25%) and confirmation of respiration as 135(91.83%), and lowest in performing artificial respiration twice(gross elevation of chest) as 97(65.98%). Accuracy of artificial respiration(%) was $28.60{\pm}16.88$ and that of chest compression(%) was $73.10{\pm}22.16$. 4) Performance ability of AED after instruction showed proper performance in power on by 141(95.91%) and attaching pad by 135(91.83%), hand-off for analyzing rhythm showed 'accuracy' in 115(78.23%) and 'non-performance' in 32(21.77%), delivery of shock and hand-off confirmation showed 'accuracy' in 109(74.14%) and 'inaccuracy' in 38(25.86%), and beginning chest compression immediately after AED was done by 105(71.42%).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.108-111
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• 2009

In this paper, the development of unmanned vehicle systems to analysis applicable communications and alternative IEEE 802.11a. IEEE 802.11b/g uses the 2.4GHz. So, using the 5GHz OFDM in IEEE 802.11a interference phenomenon better. IEEE 802.11a has a maximum speed of 54Mbps. Indoors and apartment parking on experiment to soft roaming, hard roaming. Test equipments are AP four units(RSU), reliable results for the AP one unit Bridge, Switch one unit, one server notebook, one notebook(OBU), one car. Use Softwares are Wireshark, Jperf, Ping and million second transfer was used to develop the program. So the actual car was similar to the environment. With the results of the experiment for the unmanned vehicle systems will provide the best method.

• Informatization Policy
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• v.26 no.3
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• pp.69-89
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• 2019

In order to implement smart cities that will become living spaces in the fourth industrial revolution era, detailed privacy information such as residents' living information, buildings and facilities information must be collected and processed in real time. While city functions and convenience for individuals are being facilitated, threats to personal information exposure and leakage are also likely to increase at the same time. Therefore, the design concept for personal information protection should be considered and accordingly reflected from the stages of smart city design, technology development and operation planning of intelligent information (AI) facilities. The results of the analysis show that for activation of smart cities and operation of data-driven cities, the concept of Privacy by Design (PbD) has already been introduced in the institutional, industrial and technological aspects, particularly in the cases of European countries and the US. In order to strengthen the local and global competitiveness of smart cities and the country, Korea also needs to actively deploy PbD as a strategy to secure a data-driven economy, which is the core strategy for smart cities. Therefore, the study suggests policy implications focused on approaches to legislative improvement and technology development support, which reflect the basic properties of PbD as defined in the study.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.3
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• pp.123-129
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• 2023

if we know what we're looking at, we can get a lot of information. Due to the development of eye tracking, Information on gaze point can be obtained through software provided by various eye tracking equipments. However, it is difficult to estimate accurate information such as the actual gaze depth. If it is possible to calibrate the eye tracker with the actual gaze depth, it will enable the derivation of realistic and accurate results with reliable validity in various fields such as simulation, digital twin, VR, and more. Therefore, in this paper, we experiment with acquiring and calibrating raw gaze depth using an eye tracker and software. The experiment involves designing a Deep Neural Network (DNN) model and then acquiring gaze depth values provided by the software for specified distances from 300mm to 10,000mm. The acquired data is trained through the designed DNN model and calibrated to correspond to the actual gaze depth. In our experiments with the calibrated model, we were able to achieve actual gaze depth values of 297mm, 904mm, 1,485mm, 2,005mm, 3,011mm, 4,021mm, 4,972mm, 6,027mm, 7,026mm, 8,043mm, 9,021mm, and 10,076mm for the specified distances from 300mm to 10,000mm.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.285-291
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• 2009

The aim of the present study was undertaken to investigate the association between diagnostic indices of metabolic syndrome(MetS) with carotid intima-media thickness using ultrasonography. The participants in the study were 315 male employees without carotid atherosclerosis and other cardiovascular disease. This study was approved by the Institutional Review Board of Occupational Safety and Health Research Institute. Written informed consent for the participants in this study was obtained from all individuals. Anthropometric parameters and biochemical characteristics were done using each specific equipments and the NCEP-ATP III criteria were used to define MetS. They were examined by B-mode ultrasound to measure the carotid intima-media thickness(carotid IMT) at the near and far walls of common carotid and bifurcation(bulb). The mean carotid IMT was $0.739{\pm}0.137\;mm$ and it's thickness significantly increased with the increase in age. Also, amounts of systolic and diastolic blood pressure, triglyceride and fasting glucose were significantly increased with the increase in age. Carotid IMT were significantly correlated with BMI(r=0.170, p=0.004), systolic(r=0.148, p=0.011) and diastolic blood pressure(r=0.123, p=0.036) and HDL-cholesterol(r=-0.164, p=0.005). On multiple logistic regression analysis for the diagnostic indices of MetS, carotid IMT were significantly associated with blood pressure(OR=4.220, p<0.01) and MetS(OR=1.301, p<0.05). The results indicate that blood pressure and MetS are important risk factors for carotid atherosclerosis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.449-469
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• 2011

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering during 2010. 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) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery, and new and renewable energy. Various topics were presented in the field of general thermal and fluid flow. Research issues mainly focused on the thermal reliability of axial fan and compressor in the field of fluid machinery. Studies on the design of ground source heat pump systems and solar chemical reactors were executed in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer in thermoelectric cooling/power generation systems, combined heat and power systems, carbon nano fluid with PVP, channel filled with metal foam and smoke ventilation in a rescue station of a railroad tunnel. Also the studies on flow boiling of R123/oil mixture in a plain tube bundle and R410A charge amount in an air cooled mini-channel condenser were reported. In the area of industrial heat exchangers, researches on plate heat exchanger, shell and tube heat exchanger, enthalpy exchanger, micro channel PCHE were performed. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer in thermoelectric cooling/power generation systems, combined heat and power systems, carbon nano fluid with PVP, channel filled with metal foam and smoke ventilation in a rescue station of a railroad tunnel. Also the studies on flow boiling of R123/oil mixture in a plain tube bundle and R410A charge amount in an air cooled mini-channel condenser were reported. In the area of industrial heat exchangers, researches on plate heat exchanger, shell and tube heat exchanger, enthalpy exchanger, micro channel PCHE were performed. (3) Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and CO2 were studied. Performance improvement of refrigeration systems are tried applying various ideas of refrigerant subcooling, dual evaporator with hot gas bypass control and feedforward control. The hybrid solar systems combining the solar collection devices with absorption chillers or compression heat pumps are simulated and studied experimentally as well to improve the understanding and the feasibility for actual applications. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. Various studies on heating and cooling systems, HVAC facilities, indoor air environments and energy resources were carried to improve the maintenance and management of building service equipments. In the field of heating and cooling systems, papers on a transformer cooling system, a combined heat and power, a slab thermal storage and a heat pump were reported. In the field of HVAC facilities, papers on a cooling load, an ondol and a drying were presented. Also, studies on HVAC systems using unutilized indoor air environments and energy resources such as air curtains, bioviolence, cleanrooms, ventilation, district heating, landfill gas were studied. (5) In the field of architectural environment and energy, studies of various purposes were conducted such as indoor environment, building energy, renewable energy and green building. In particular, renewable energy and building energy-related researches have mainly been studied reflecting the global interest. In addition, many researches which related the domestic green building certification of school building were performed to improve the indoor environment of school.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.492-507
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• 2010

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2009. 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) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery and piping, and new and renewable energy. Various topics were covered in the field of general thermal and fluid flow such as an expander, a capillary tube, the flow of micro-channel water blocks, the friction and anti-wear characteristics of nano oils with mixtures of refrigerant oils, etc. Research issues mainly focused on the design of micro-pumps and fans, the heat resistance reliability of axial smoke exhaust fans, and hood systems in the field of fluid machinery and piping. Studies on ground water sources were executed concerning two well type geothermal heat pumps and multi-heat pumps in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included the heat transfer in thermoelectric cooling systems, refrigerants, evaporators, dryers, desiccant rotors. In the area of industrial heat exchangers, researches on high temperature ceramic heat exchangers, plate heat exchangers, frosting on fins of heat exchangers were performed. (3) In the field of refrigeration, papers were presented on alternative refrigerants, system improvements, and the utilization of various energy sources. Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and $CO_2$ were studied. Efforts to improve the performance of refrigeration systems were made applying various ideas of suction line heat exchangers, subcooling bypass lines and gas injection systems. Studies on heat pump systems using unutilized energy sources such as river water, underground water, and waste heat were also reported. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. In the area of cogeneration systems, papers on energy and economic analysis, LCC analysis and cost estimating were reported. Studies on ventilation and heat recovery systems introduced the effect on fire and smoke control, and energy reduction. Papers on district cooling and heating systems dealt with design capacity evaluation, application plan and field application. Also, the maintenance and management of building service equipments were presented for HVAC systems. (5) In the field of architectural environment, various studies were carried to improve indoor air quality and to analyze the heat load characteristics of buildings by energy simulation. These studies helped to understand the physics related to building load characteristics and to improve the quality of architectural environment where human beings reside in.

• Archives of design research
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• v.18 no.4 s.62
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• pp.85-94
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• 2005

The purpose of this research is the activation proposal about the local design innovation center that was established as a national design policy For this proposal, I have to research about the established process of local design innovation center and then, I analyzed the present condition of local design innovation center for the promoting plan. As a result, we must establish three basic elements to activate the local design center. the first, we have to know the local characteristic. the second, we have to make up the management direction of local design center the third, we have to get the sympathy from the local administration and local people for the positive support. With above conditions, the local design innovation center have to arrange infra elements. (1) design developing facilities for the lending to the local designer, (2) professional designer for the developing of design industry, (3) program development for various activities, (4) the trend research for supply to local company, (5) design one stop service support, (6) the network foundation construction between design administration and design company for the active communication, (7) the innovation of design center for the benefit model, (8) the local design policy establishment with local administration, (9) the independent management of responsibility for the fulfillment For the promotion of the local design innovation center have to make efforts continually with below listed elements. 1. Design supporting for the local industry 2. Various design campaign for the spreading of public recognition about design 3. The supporting for design company and local company with established facilities and expensive equipments. 4. The construction of design information infra for local company 5. The development of new program about the connection between industry and university. 6. The development of local characteristic and local image innovation to make new local where we are.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.10-16
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• 2009

Purpose: As the number of patients has increased since the installation of a PET/CT, we are now examining about 2500-3000 annually. We have realized that if we properly adjust a pitch under the same condition of a CT during a PET/CT exam, radiation quantity that reaches the patient can change. In order to reduce the exposure dose of a patient, the research examines a method of reducing the exposure dose of a patient by controlling the pitch during a PET/CT exam, viewing whether the adjustment of the pitch influences CT image and PET SUV. Methods: The equipment used is a Biograph Positron Emission Tomography (PET) Scanner (CT type: TRCT-240-130 (WCT-240-130)) of Siemens company. For the evaluation of exposure dose of a patient, we measured radiation quantities using a PTW-DIADOS 11003/1383, which is a CT radiation measurement instrument used by Siemens. We measured and analyzed the space resolutions of CT images caused by the change of pitches using an AAPM Standard Phantom in order to see how the adjustment of pitches influenced the CT images. In addition, in order to obtain SUVs caused by each change of pitches using a PET source made with a solid radioactive cylinder phantom, we confirmed whether the SUVs changed in the PET/CT images by calculating the SUVs of the fusion images caused by the change of pitches after obtaining CT and PET images and finishing the test. Results: 2slice CT scanner showed that radiation quantities largely dropped when pitches ranged from 0.7 to 1.3 and that the reduction of radiation quantities were smaller when pitches ranged from 1.5 to 1.9. That is, we found that the bigger pitch values are the smaller the radiation quantities of a patient are. Moreover, we realized that there is no change of SUVs caused by the increase of pitches and that pitch values do not influence PET SUVs and the quality of CT images. It is judged that using 1.5 as a pitch value contributes to the reduction of exposure dose of a patient as long as there is no problem in the quality of an image. Conclusions: When seeing the result of the research, hospital using a PET/CT should make an effort to reduce the exposure dose of a patient seeking pitch values appropriate for their hospital within the range in which there is no image distortion and PET SUVs are not influenced from pitches. We think that the research can apply to all multi-detectors having a CT scanner and that such a research will be needed for other equipments in the future.