• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.59-66
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• 2022

In order to solve the problem of urban traffic congestion, Urban Air Mobility (UAM) concept using Electric Vertical Take-off and Landing (eVTOL) aircraft has been gaining popularity, and many domestic and international studies are underway. However, since these aircraft inevitably fly over densely populated areas, it is essential to ensure safety, which starts with accurately analyzing the crash risk. In this paper, the locations and impact speeds of crash are computed using six degree-of-freedom simulations of an eVTOL aircraft in a fixed-wing mode. System malfunction was modeled by a sudden loss of thrust with control surfaces being stuck during cruise. Because most of these eVTOL aircraft are still under development, a methodology of constructing a six degree-of-freedom dynamics model from generic specification is also developed. The results show that the crash locations are highly concentrated right under the aircraft within a square that has an edge length similar to the cruise altitude. Speed distribution is more complicated because almost identical crash locations can be achieved by two very different paths resulting in a large variation in the speeds.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.593-605
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• 2022

The purpose of this study is to investigate the personalized treacmill exercise analysis using a smart mirror based on Kinect sensor. To evaluate the performance of the development system, 10 health males were used to measure the range of the hip joint, knee joint, and ankle joint using a smart mirror when walking on a treadmill. For the validity and reliability of the development system, the validity and reliability were analyzed by comparing the human movement data measured by the Kinect sensor with the human movement data measured by the infrared motion capture device. As a result of validity verification, the correlation coefficient r=0.871~0.919 showed a high positive correlation, and through linear regression analysis, the validity of the smart mirror system was 88%. Reliability verification was conducted by ICC analysis. As a result of reliability verification, the correlation coefficient r=0.743~0.916 showed high correlation between subjects, and the consistency for repeated measurement was also very high at ICC=0.937. In conclusion, despite the disadvantage that Kinect sensor is less accurate than the motion capture system, Kinect is it has the advantage of low price and real-time information feedback. This means that the Kinect sensor is likely to be used as a tool for evaluating exercise prescription through human motion measurement and analysis.

• Journal of dental hygiene science
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• v.11 no.2
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• pp.99-105
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• 2011

In this study a survey was conducted with 431 students at the department of dental hygiene in three regions from April 2010 to investigate various actual states and levels of perception of their major commitment. Department-Climate and levels of major commitment were classified and described through cross-tabulation analysis; multinomial logistic regression analysis was used to predict the level of major commitment perceived for department climate and identify its influence. Major commitment classified into three levels about Inferiority, Normality and Superiority. Recognition factor of Major field was divided into external factor, eternal factor. External factor classified into professor, friends, facilities, administration-service and quality of education. As well as, eternal factor was department climate. Eternal factor consisted of relationship dimensions, goal-orientation dimensions, system maintenance dimensions and system change dimensions. This study was conducted to get a phenomenal understanding of students' learning in the major field and their school life. With this study, if friends and professor raise students at the Department of Dental Hygiene's department-climate recognition, their major-commitment will rise. And high major-commitment will be bring about their professional ability.

• Journal of Broadcast Engineering
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• v.10 no.1 s.26
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• pp.43-56
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• 2005

In the existing broadcasting environment, it is not easy to serve the bi-directional service between a broadcasting server and a TV audience. In the uni-directional broadcasting environments, almost TV programs are scheduled depending on the viewers' popular watching time, and the advertisement contents in these TV programs are mainly arranged by the popularity and the ages of the audience. The audiences make an effort to sort and select their favorite programs. However, the advertisement programs which support the TV program the audience want are not served to the appropriate audiences efficiently. This randomly provided advertisement contents can occur to the audiences' indifference and avoidance. In this paper, we propose the target advertisement service for the appropriate distribution of the advertisement contents. The proposed target advertisement service estimates the audience's profile without any issuing the private information and provides the target-advertised contents by using his/her estimated profile. For the experimental results, we used the real audiences' TV usage history such as the ages, fonder and time of the programs from AC Neilson Korea. And we show the accuracy of the proposed target advertisement service algorithm. NDS (Normalized Distance Sum) and the Vector correlation method, and implementation of our target advertisement service system.

• Journal of Dairy Science and Biotechnology
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• v.32 no.1
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• pp.17-29
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• 2014

GRAS probiotics can be used to modulate intestinal microbiota and to alleviate various gastrointestinal disorders. In several recent studies, researchers have explored the potential expansion and usability of probiotics to reduce the risk factors associated with diseases, including obesity, hypercholesterolemia, arterial hypertension, hyperhomocysteinemia, and oxidative stress. In this review, our aim was to clarify the mechanism underlying interactions between hosts (animal or human) and probiotics and the beneficial effects of probiotics on human health.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.265-274
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• 1998

Purpose : This prospective study has been conducted to assess the value of three dimensional conformal radiation therapy (3DCRT) for lung cancer and to determine its potential advantage over current treatment approaches. Specific aims of this study were to 1) find the most ideal 3DCRT technique 2) establish the maximum tolerance dose that can be delivered with 3DCRT and 3) identify patients at risk for development of radiation pneumonitis. Materials and Methods : Beginning in Nov. 1994, 95 patients with inoperable non-small cell lung cancer (stage I; 4, stage II; 1, stage IIIa; 14, stage IIIb; 76) were entered onto this 3D conformal trial Areas of known disease and elective nodal areas were initially treated to 45 Gy and then using 3DCRT technique 65 to 70 Gy of total dose were delivered to the gross disease. Sixty nine patients received 65 Gy of total dose and 26 received 70 Gy Seventy eight patients (82.1$\%$) also received concurrent MVP chemotherapy. 3DCRT plans were compared with 2D plans to assess the adequacy of dose delivery to target volume, dose volume histograms for normal tissue, and normal tissue complication Probabilities (NTCP). Results : Most of plans (78/95) were composed of non-coplanar multiple (4-8) fields. Coplanar segmented conformal therapy was used in 17 pateints, choosing the proper gantry angle which minimize normal lung exposure in each segment. 3DCRT gave the full dose to nearly 100$\%$ of the gross disease target volume in all patients. The mean NTCP for ipsilateral lung with 3DCRT (range; 0.17-0.43) was 68$\%$ of the mean NTCP with 2D treatment planning (range; 0.27-0.66). DVH analysis for heart showed that irradiated volume of heart could be significantly reduced by non-coplanar 3D approach especially in the case of left lower lobe lesion. Of 95 patients evaluable for response, 75 (79$\%$), showed major response including 25 (26$\%$) with complete responses and 50 (53$\%$) with partial responses. One and two rear overall survivals of stage III patients were 62.6$\%$ and 35.2$\%$ respectively. Twenty percent (19/95) of patients had pneumonitis; Eight patients had grade 1 pneumonitis and 11 other patients had grade 2. Comparison of the average of NTCP for lung showed a significant difference between patients with and without radiation pneumonitis. Average NTCP for Patients without complication was 62$\%$ of those with complications. Conclusions : This study showed that non-coplanar multiple fields (4-8) may be one of the ideal plans for 3DCRT for lung cancer. It also suggested that 3DCRT may provide superior delivery of high dose radiation with reduced risk to normal tissue and that NTCP can be used as a guideline for the dose escalation.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.133-140
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• 2003

In this study, muscle activity was measured using surface EMG (sEMG) during a voluntary maneuver (ankle dorsiflexion) in the supine position was compared pre and post gait training. Nine patients with incomplete spinal cord injury participated in a supported treadmill ambulation training (STAT), twenty minutes a day, five days a week for three months. Two tests, a gait speed test and a voluntary maneuver test, were made the same day, or at least the same week, pre and post gait training. Ten healthy subjects' data recorded using the same voluntary maneuvers were used for the reference. sEMG measured from ten lower limb muscles was used to observe the two features of amplitude and motor control distribution pattern, named response vector. The result showed that the average gait speed of patients increased significantly (p〈0.1) from 0.47$\pm$0.35 m/s to 0.68$\pm$0.52 m/s. In sEMG analysis, six out of nine patients showed a tendency to increase the right tibialis anterior activity during right ankle dorsiflexion from 109.7$\pm$148.5 $mutextrm{V}$ to 145.9$\pm$180.7 $mutextrm{V}$ but it was not significant (p〈0.055). In addition, only two patients showed increase of correlation coefficient and total muscle activity in the left fide during left dorsiflexion. Patients' muscle activity changes after gait training varied individually and generally depended on their muscle control abilities of the pre-STAT status. Response vector being introduced for quantitative analysis showed good Possibility to anticipate. evaluate, and/or guide patients with SCI, before and after gait training.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.201-213
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• 2007

In this study, the Batter Assessment Science Integrating point and Nonpoint Sources (BASINS 3.0)/window interface to Hydrological Simulation Program-FPRTRAN (WinHSPF) was applied for assessment of Soyang Dam watershed. WinHSPF calibration was performed using monitoring data from 2000 to 2004 to simulate stream flow. Water quality (water temperature, DO, BOD, nitrate, total organic nitrogen, total nitrogen, total organic phosphorus and total phosphorus) was calibrated. Calibration results for dry-days and wet-days simulation were reasonably matched with observed data in stream flow, temperature, DO, BOD and nutrient simulation. Some deviation in the model results were caused by the lack of measured watershed data, hydraulic structure data and meteorological data. It was found that most of pollutant loading was contributed by nonpoint source pollution showing about $98.6%{\sim}99.0%$. The WinHSPF BMPRAC was applied to evaluate the water quality improvement. These scenarios included constructed wetland for controlling nonpoint source poilution and wet detention pond. The results illustrated that reasonably reduced pollutant loadin. Overall, BASINS/WinHSPF was found to be applicable and can be a powerful tool in pollutant loading and BMP efficiency estimation from the watershed.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.43-53
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• 2004

The current Korean Concrete Design Code(KCI Code) requires the minimum and maximum content of shear s in order to prevent brittle and noneconomic design. However, the required content of the steel reinforcement In KCI Code is quite different to those of the other design codes such as fib-code, Canadian Code, and Japanese Code. Furthermore, since the evaluation equations of the minimum and maximum shear reinforcement for the current KCI Code were based on the experimental results, the equations can not be used for the RC members beyond the experimental application limits. The concrete tensile strength, shear stress, crack inclination, strain perpendicular to the crack, and shear span ratio are strongly related to the lower and upper limits of shear reinforcement. In this research, an evaluation equation for the minimum content of shear reinforcement is theoretical proposed from the Wavier's three principals of the mechanics of materials.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.186-192
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• 2002

Purpose : Measurement of transmission dose is useful for in vivo dosimetry. In this study, previous algorithm for estimation of transmission dose was modified for use in cases with tissue deficit. Materials and Methods : The beam data was measured with flat solid phantom in various conditions of tissue deficit. New algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. The algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients using multiple sheets of solid phantoms. Results : The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within ${\pm}1.0\%$ in most situations and within ${\pm}3.0\%$ in experimental settings with irregular contours mimicking breast cancer treatment set-up. Conclusion : Developed algorithm could accurately reflect the effect of tissue deficit and irregularly shaped body contour on transmission dosimetry.