• International Journal of Aeronautical and Space Sciences
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• v.6 no.1
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• pp.71-76
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• 2005

The KOMPSAT-1 satellite, launched into a circular sun synchronous orbit on Dec. 21, 1999, entered its$6^{th}$year of successful operation this year. The purposes of the mission are to collect earth images (6.6 m resolution), multi-spectral images of the ocean, and to collect information on the particle environment of the low earth orbit. For normal operation, KOMPSAT-1 orbits are determined using GPS navigation solutions. However, at the start of the life of KOMPSAT-1, the 11-year solar activity cycle was at a maximum. Solar flux was maintained at this level until 2002, and thereafter reduced to a moderate level by 2004. Thus, the OD (Orbit Determination) accuracy has varied according to the solar activity. This paper presents the degree to which the OD accuracy could be degraded during a high solar activity period compared with that of a (relatively) low solar activity period. We investigated the effect of the use of solve-for parameters such as a drag coefficient ($C_D$), solar radiation coefficient ($C_R$), and the general accelerations ($G_A$) on OD accuracy with solar activity. For the evaluation of orbit determination accuracy, orbit overlap comparison is used since no independent orbits of comparable accuracy are available for comparison. The effect of the use of a box-wing model instead of a constant cross-sectional area is also investigated.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.4
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• pp.131-138
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• 2018

PURPOSE: This study was conducted to compare the muscle activity of the proximal muscles of the lower limb according to the distance between the front and rear foot during lunge and to determine the most effective foot position for activation of the proximal muscle in the limb. METHODS: A total of 49 young adults were enrolled in this study. All subjects performed lunge by positioning the big toe of the back foot and the heel of the front foot at intervals of 40%, 60%, and 80% of the subject's own leg length. Muscle activity of the vastus medialis oblique, rectus femoris (RF), vastus lateralis oblique (VLO), gluteus medius, biceps femoris, and semitendinosus (ST) was then measured during three intervals of lunge operation. Each operation was measured three times for 10 seconds each, after which the average value was calculated and analyzed. RESULTS: There were significant differences in muscle activities of RF, VLO, and ST among the three intervals of the foot (p<.05). Post hoc, comparisons revealed lunge at 40% intervals resulted in higher RF and VLO activity than at 60% and 80% intervals (p<.05). In the semitendinosus muscle, 80% leg length intervals showed higher muscle activity than 40% (p<.05). CONCLUSION: Strengthening of the proximal muscles of the lower extremities during lunge exercise is considered to be most effective when placing the fore- and rear foot at intervals corresponding to 40% of the leg length.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.739-742
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• 1997

A remote drum grappling device coupled to the anti-swing crane has been developed by KAERI to cope with problems involved in manually treating low level waste drums. In order for this grappling device to be operated effectively, multi-sensors including CCD camera were employed. As an activity representation scheme of the device, Extended State Machine (ESM) was used to descibe its operation sequences. The performance testing of the device was conducted successfully, and consequently its application could be extendable to industrial operation environment.

• Archives of Craniofacial Surgery
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• v.21 no.1
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• pp.3-6
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• 2020

Nowadays, the incidence of nasal bone fracture is increasing because of social complexity with frequent social activity, and reduction of fractures is relatively simple and can be corrected in short operation time. However, the postoperative results are known to be less satisfied with higher complication rates relatively. These problems could have resulted from inaccurate recognition and interpretation of fracture aspect, inaccurate planning of operation resulting in under or overcorrection, ignoring septal management, complication related nasal packings with removal, postoperative management, and patient satisfaction with complication.

• Nuclear Engineering and Technology
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• v.31 no.1
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• pp.9-16
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• 1999

A 330 MWt-sized multi-purpose integral-type reactor, SMART is under development in Korea for the use of nuclear energy other than electricity generation. In this study, various radioactive source terms are estimated for SMART. SMART is different from conventional reactor concepts in operation and design. Therefore Specific Calculation method namely recurrence model is used. This model is based on the change rate in the RC radioactivity materials and operational characteristics of SMART Calculation results show tremendously increase of the levels of RC activity because no cleanup of RC and long term operation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.47-50
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• 1999

From 1997 irrigation water withdraws has been surveyed for the purpose of river operation and management . Recently , the River Law was revised (1999.2.8) and obligate to water users to report their proposed and actual water withdrawals. If we can save more water from rice paddy area, we can use more water for municipal and industrial activity and we can expect water quality should be improved in the river. So the role of irrigation water use efficiency is more and more important.

• Journal of the Korean Arthroscopy Society
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• v.12 no.3
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• pp.205-210
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• 2008

Purpose: To evaluate the clinical results after microfracture surgery for full-thickness chondral lesion of the knee. Materials and Methods: Thrity-seven patients, who had underwent microfracture surgery for full-thickness chondral lesion of the knee between January 1999 and December 2005, were reviewed. Their mean age at the time of operation was 31 years (range, 21~38 years) and mean follow up period was 2.7 years. All patients were reviewd every 6 months after operation. Clinical outcomes were evaluated by activity of daily living (ADL), Tegner activity scale, International Knee Documentation Committee (IKDC) knee examination form, Lysholm score and satisfaction of treatment. Results: ADL and Tegner activity score improved in 83% of patients during first 18 months, but decreased during next 6months. IKDC score improved from 58 points at operation time to 86 points after 12 months, but decreased to 79 points and 68 points at 18 and 24 months after operation, respectively. Also, Lysholm score improved from 61 points at operation time to 89 points after 12 months, to 92 points after 18 months, but 73 points after 24 months. At the last follow-up, 22 patients were excellent or good in satisfaction of treatment, whereas 12 patients were fair, 3 patients were poor. Conclusion: Microfracture surgery for full-thickness chondral lesion of the knee has a good functional improvement for first 12 months after operation, but its effectiveness has decreased over time.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.861-864
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• 2011

Since national GHG reduction target by 2020 has been presented in Korea, the role of railroad has been reinforced within transport system due to the allocation of reduction target into sector. So, it is necessary to manage activity data systematically for the calculation of GHG emission in railroad. Now, the activity data of diesel consumption for NIR(National Inventory Report) are provided from oil supply and demand statistics. On the other hands, the activity data collected directly from railroad operating companies are used for GHG & Energy Target Management Act. This study aimed to assess the GHG emissions using two kinds of activity data related to the diesel consumption of railroad in 2009 and 2010. As a result, GHG emissions based on oil supply and demand statistics was 636 thousands ton $CO_{2e}$, but the activity data collected from railroad operating companies showed 649 thousands ton $CO_{2e}$ in 2009. Also, the gap of $CO_{2e}$ emission was increased in 2010. These trends were caused because oil supply and demand statistics included total diesel sales volume during 1 year and the activity data collected from railroad operating companies were the amount of diesel consumption only at railcar operation and maintenance step. In conclusion, it is important to develop the management and verification system of activity data with high reliability to substitute oil supply and demand statistics in railroad sector.

• The Journal of Sustainable Design and Educational Environment Research
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• v.9 no.1
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• pp.41-51
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• 2010

It is high level of management activity for the fixed property of building to operating spaces for education in university campus. Therefore, this study is focused on definition of the factors for analyzing the actual conditions of space operation and application of them to C university campus in Gyeongbuk in the aspect of infrastructure of university and efficiency of space operation. These analytical factors are the rate of lecture and experimentation room, the rate of theoretical and experimental subject in curriculum and unit area for infrastructure and the rate of use, turnover rate and occupation rate per lecture for space operation. If the analytical factors of space operation are systemized as program module for space operation, the space management system of university campus will be characterized on the foundation of university information system. And it will be able to support the decision making about space management. It needs to integrate various type of information and data of university to increase the efficiency of decision making.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.4
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• pp.386-394
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• 2012

Recent trends in the flexible manufacturing systems are morphing cell control for the shop-wide production operation system and providing the integrated operation and execution system together with vendor-specific FMC/FMS platform. In these requirements, the shop-floor level operation system plays a role of coordinating the control activity of each cell, and has to provide flexibility for the complexity of mixed operations of various cells. This paper suggests a system architecture for the mixed environments of multi-cells and job shop, its corresponding enabling technologies based on comparative studies with other related studies and commercialized systems. This approach includes a process definition model considering the integration with upper BOM-BOP and external service modules, and reconfigurable device-level interface which provides dynamic interconnections with machine tools and cell controllers. The function modules and their implementation results are also described to provide the feasibility of the proposed approaches as the flexible shop-floor operation system for the multi-cell environments.