• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.170-176
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• 2003

The pantograph for Korean High Speed Train was developed and had been evaluating by through "G7- R＆D for home grown high speed train technology". In this study, a relation in mechanical aspect between the train running speed and the current collecting performance of the pantograph is conducted.'for this study, a measuring system for current collecting performance and mechanical characteristics is developed and installed on the prototype Korean High Speed Train, and measurement is conducted while the train runs on the test track. The measuring system is composed of video monitoring system and telemetry & data processing unit. It monitors whether the hazard behavior in the pantograph is occurs or not, and measures acceleration and vertical contact force between the pan head and catenary. Through this study, evaluation of a mechanical vibration characteristics and trend of the pantograph and a interface performance of pantograph - catenary up to 200㎞/h train speed are facilitated.

• International Journal of Aerospace System Engineering
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• 제2권1호
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• pp.1-5
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• 2015

The Unmanned Air Vehicle (UAV) systems are indispensable tools of air surveillance and reconnaissance nowadays. Via this systems, hazardous end risky intelligence gathering activities are handled easily. Although they are named as "Unmanned" the UAV systems are commanded by pilots/operators. So, because of weather conditions, enemy attacks etc. as well as pilot error it is possible to face with sudden Round per Minute (RPM) drops and subsequently engine cut/stop during a mission flight at high altitudes. In this case, there are some very urgent decisions to make and rapid "emergency procedure" steps to take in a very short time before Line of Sight (LOS) is lost. The time before crash and the distance to landing air base need to be calculated, the Return Home route need to be checked and the landing/crash side need to be determined. Therefore it is a vital necessity that UAV pilots have some extra qualifications like being determined, well instructed and trained, experienced apart from operating ability. Within this scope, for an education process of a UAV pilot experience sharing and lessons learned are as important as simulators even more. By means of lessons learned it is possible to find out the reasons, mistakes and prevent the likely UAV accidents. In this study it is told about a real UAV crash, experienced of the pilot, the dos and don'ts and the difficulties. Thus it is aimed to help the people who can experience the same or similar situations in future.

• Journal of the Korean Applied Science and Technology
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• 제35권4호
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• pp.1108-1119
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• 2018

As the interest on the air pollution is gradually rising at home and abroad, automotive and fuel researchers have been studied on the exhaust and greenhouse gas emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward two main issues : exhaust emissions (regulated and non-regulated emissions, PM particle matter) and greenhouse gases of vehicle. Exhaust emissions and greenhouse gases of automotive had many problem such as the cause of ambient pollution, health effects. In order to reduce these emissions, many countries are regulating new exhaust gas test modes. Worldwide harmonized light-duty vehicle test procedure (WLTP) for emission certification has been developed in WP.29 forum in UNECE since 2007. This test procedure was applied to domestic light duty diesel vehicles at the same time as Europe. The air pollutant emissions from light-duty vehicles are regulated by the weight per distance, which the driving cycles can affect the results. Exhaust emissions of vehicle varies substantially based on climate conditions, and driving habits. Extreme outside temperatures tend to increasing the emissions, because more fuel must be used to heat or cool the cabin. Also, high driving speeds increases the emissions because of the energy required to overcome increased drag. Compared with gradual vehicle acceleration, rapid vehicle acceleration increases the emissions. Additional devices (air-conditioner and heater) and road inclines also increases the emissions. In this study, three light-duty vehicles were tested with WLTP, NEDC, and FTP-75, which are used to regulate the emissions of light-duty vehicles, and how much emissions can be affected by different driving cycles. The emissions gas have not shown statistically meaningful difference. The maximum emission gas have been found in low speed phase of WLTP which is mainly caused by cooled engine conditions. The amount of emission gas in cooled engine condition is much different as test vehicles. It means different technical solution requires in this aspect to cope with WLTP driving cycle.

• Journal of Digital Contents Society
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• 제6권1호
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• pp.55-62
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• 2005

In this paper, we propose the new technique to compute the optimal route by considering the direction of distribution vehicles and the location for delivery, developing the algorithm of the shortest route to approach the location as applying the gemetic algorithm. This approach makes it possible for us to find the best route even under itineraries which include many destinations. Lively studies are currently in progress on the development of vehicle navigation software, combining PDA GPS, and electronic maps. Many web-sites are providing a varier of services which use electronic maps. Popular among these services is one that computes the optimal route between two positions that a user inputs. This service of computing the optimal route plays an important role in distribution industries such as home-delivery. For the distribution system. the construction of a vehicle regulation system enables us to calculate and manipulate the optimal route for distribution vehicles, to enhance the efficiency in making use of vehicles and labor, and to reduce costs.

• Journal of Families and Better Life
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• 제20권6호
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• pp.81-93
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• 2002

The purpose of this study is to analyze the effects of household income drops on household economic status during economic crisis periods. Using the data taken from Korean Household Panel Study for 1996 and 1998, it was investigated how household income change affected household income, expenditure, and assets/debt. The economic status change of the income-decreased group was compared with that of the income-increased group. The major findings were as follows: Average income of the total sample was 1,905 thousand won in 1996, while 1,419 thousand won in 1998. The household of which income was decreased during the period was 65.1% of total sample. Average income of the group was reduced from 2,263 thousand won to 1,239 thousand won. Among income sources, the amount of income from real asset was found to be the highest decreasing rate, and the amounts of both business and employed-work income were reduced almost up to an half of those in two years ago. The amounts for all expenditure categories were also decreased with decreasing household income. Especially the expenditures for food away from home, leisure, durable, recreation, and vehicle-related expense were found to have the highest income elasticity. The households with decreased income were found to reduce household expenditures by 377 thousand won per month, which was 70.9% of that in 1996. Decreases in household income resulted in decreases in net wealth by 10,170 thousand won. With decreases in household income, the amounts of total insurance and private savings such as gye were decreased, and so were the amounts of real assets and monetary assets.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 한국미생물생명공학회 2003년도 2003 Annual Meeting, BioExhibition and International Symposium
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• pp.55-62
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• 2003

The mucosal immune system provides a first line of defense against invasion of infectious agents via inhalation, ingestion and sexual contact. For the induction of protective immunity at these invasion sites, one must consider the use of the CMIS, which interconnects inductive tissues, including PP and NALT, and effector tissues of the intestinal, respiratory and genitourinary tracts. In order for the CMIS to induce maximal protective mucosal immunity, co-administration of mucosal adjuvant or use of mucosal antigen delivery vehicle has been shown to be essential. When vaccine antigen is administered via oral or nasal route, antigen-specific Th 1 and Th2 cells, cytotoxic T lymphocytes(CTLs) and IgA B cell responses are effectively induced by the CMIS. In the early stages of induction of mucosal immune response, the uptake of orally or nasally administered antigens is achieved through a unique set of antigen-sampling cells, M cells located in follicle-associated epithelium(FAE) of inductive sites. After successful uptake, the antigens are immediately processed and presented by the underlying DCs for the generation of antigen-specific T cells and IgA committed B cells. These antigen-specific lymphocytes are then home to the distant mucosal effector tissues for the induction of antigen-specific humoral(e.g., IgA) and cell-mediated (e.g., CTL and Th1) immune responses in order to form the first line of defense. Elucidation of the molecular/cellular characteristics of the immunological sequence of mucosal immune response beginning from the antigen sampling and processing/presentation by M cells and mucosal DCs followed by the effector phase with antigen-specific lymphocytes will greatly facilitate the design of a new generation of effective mucosal antigen-specific lymphocytes will greatly facilitate the design of a new generation of a new generation of effective mucosal adjuvants and of a vaccine deliver vehicle that maximizes the use of the CMIS.

• Clinical and Experimental Pediatrics
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• 제61권8호
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• pp.253-257
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• 2018

Purpose: Child safety seats (CSS) are critical for the protection of children, in case of motor vehicle accidents. Although the national legislation mandates that all newborns must be placed in an appropriately installed CSS during transportation, people often do not perceive the importance of CSS and do not use it as recommended. The purpose of this survey was to understand the use of CSS for the safe transport of newborns from hospital to home. Methods: We interviewed parents of newborn infants, using a structured questionnaire, at the time of their discharge from Cheil General Hospital & Women's Health Care Center, between May 2014 and July 2014. Results: A total of 403 participants were interviewed. The rate of CSS use was only 14.9%. Overall, 76.4% of the families interviewed were not aware about the recommendations on CSS use for newborns when travelling in a car. The provision of education on using CSS significantly influenced their rate of use. Parents who were educated about mounting the CSS in a car used it more as compared with others (25.7% vs. 12.2%) (P=0.002). Furthermore, if parents had heard about the importance or necessity of CSS, they used it more than others did (19.5% vs. 10.6%, P=0.032). Conclusion: Despite the legal regulation, most parents transport their newborn infants without a CSS while traveling from hospital to their home. The rate of CSS use was influenced by parental education and their knowledge about its necessity. Education programs for parents must be reinforced to increase the CSS use.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권11호
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• pp.7957-7963
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• 2015

R&D trend for Auxiliary Power Supply(APU) of electric vehicle can be well understood by analyzing patents at home and abroad. Based on this trend analysis, domestic technology development direction is proposed. To get technique trend, patents of Korea, Japan, Europe and America published until February of 2014 are analyzed by WIPS DB. First, power converter and transformer two big category are classified. Power converter can be classified into resonant DC to DC converter and resonant Half bridge inverter; transformer can be classified into high frequency transformer, ferrite transformer and matching transformer. By analyzing R&D trend of different counties, companies and years, specific technology needed to be developed and trend of technology can be accurately grasped.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제50권8호
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• pp.559-572
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• 2022

Recently, with the success of the world's first On-Orbit service (OOS) mission MEV (Mission Extension Vehicle)-1 in 2020, interest in OOS is increasing at home and abroad. In particular, the mission of OOS and active debris removal (ADR) service, which was difficult to find in the old space era in the past, is expected to enter the new space industry in the near future. Therefore, this paper examines the development cases of domestic and foreign OOS technologies, and describes the characteristics of major technologies required, domestic status and development potential, and the possibility of future OOS mission development. The technology trends and future prospects of OOS described in this paper are expected to be useful reference materials for further researching related fields in domestic situations where related research is insufficient.

• Journal of Institute of Control, Robotics and Systems
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• 제13권10호
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• pp.1025-1031
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• 2007

GPS is widely used for positioning applications and attitude of a vehicle can be found also with multiple antennas. However, extremely weak signal level prevents GPS from indoor operation. DR with accelerometers and gyros and landmark based localization method used for indoor applications increase complexity and cost. In this paper, a simple but very efficient ultrasound based attitude determination system which determines both position and attitude in WSN is given. The range between transmitter and receivers are measured using the arrival time difference between ultrasound and RF signal. The 3 dimensional positions can be found using more than 3 range measurements. Furthermore, if more than 2 transmitters are used, the attitude can be determined using the baseline vectors obtained by differencing transmitter and receiver positions. The prototype system is implemented to evaluate the performance of the proposed method. In addition, an error analysis shows the relation between the attitude error and basel me length, quality of measurement and orientation of a vehicle. The static and dynamic experiments performed by micro mobile robot shows accurate position with less than 1.5cm error and attitude with less than 1 degree error can be obtained continuously with 20cm baseline. It is expected that these results can be adapted without modification to indoor applications such as home cleaning robot and autonomous wheelchair maneuvering.