• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1575-1580
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• 2006

High speed and large transfer capability of railroad has been an important issue in Korean since KTX opening at 2004. Improvement projects for railway electrification are progressed in the conventional line as well as high speed line because various operation plan is performed such as interaction between high speed line and conventional line and operation of tilting train etc. Especially, railway electrification has many advantages which are cost effective and eco-friendly. But it also has some problems such as construction costs and accidents due to electrification. Therefore this paper developed measuring index of electrification railway benefit. By comparing between diesel and electrical locomotive, the operations of before and after the electrification and measurements quantitative index such as energy efficiency, enlargement of transfer capability, environmental pollution and maintenance and efficiency of operation is presented. In the future, Overall benefit and cost of railway electrification will be analyzed.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.22 no.2
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• pp.15-20
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• 2016

Background: The purpose of this study was to compared of scapular position between operation side and non-operation side to the rotator cuff surgery. Methods: This study was carried out with a total 34 patients: male (n=14), female (n=20). Shoulder range of motion (ROM), the quadruple visual analogue scale (QVAS), the shoulder pain and disability index (SPADI), and the scapular index (SI) were used to assess shoulder posture and function. SI was the resting position of the scapular was determined by measuring the distance from the mid-point of the sternal notch (SN) to the medial aspect of the coracoid process (CP) and the horizontal distance from the posterolateral angle of the acromion (PLA) to the thoracic spine (TS) with a soft tape measure. The SI was calculated using the equation: [(SN to CP/PLA to TS) ${\times}$ 100]. Results: There were no significant difference in ROM, QVAS to rotator repair patients according to SI (p>.05). There were significant differences in SI between the operation side and the non-operation side (p<.01). Conclusions: Scapular position was operation side more internal rotation, protraction, abduction than non-operation side. Therefore, health professionals managing for rotator cuff tear repair patients should consider scapular position.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.77-85
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• 2013

The efficient operation and management strategies of reservoirs in irrigation periods of drought events are an essential element for drought planning and countermeasure. Korea Rural Community Corporation has developed the real-time water level observation system of agricultural reservoirs to efficiently operate reservoirs, however, it is not possible to predict drought conditions, and only provides information of current situation. Hence, it is necessary to evaluate accurate irrigation vulnerability and efficiently reservoir operation rules using current water level. In this paper, the improvement methods of reservoir operation planning were developed with water supply vulnerability characteristic curves comparing to automatic water gauge at agricultural reservoirs. The 11 reservoirs were simulated applying the reservoir operation rules which was determined by irrigation vulnerability characteristic curves criteria and real time water level, and evaluated water supply situation in 2012 year. The analysis of results can be identified probabilistic possibility of water supply failures compared with the existing reservoir operation criteria. These results of efficient reservoir operation rules can be achieved enable irrigation planners to optimally manage available water resources for decision making, and contributed to maintain the water supply according to demand strategy for agricultural reservoirs management.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.31-37
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• 2004

We have proposed a design methodology for large active-area single-mode VCSELS, which have higher reliability and output power, and are well-suited for high-speed operation. The key idea underlying the design methodology is to reduce the effective index difference between active and cladding regions by controlling the thickness and position of the oxide layer. The idea is confirmed by the self-consistent effective index method. By placing the oxide layer position properly, we can increase the radius of the oxide aperture for single-mode operation by 3 times.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.205-210
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• 2014

The micro grid considered in this paper consists of a diesel generator, a photovoltaic array, a wind turbine, a fuel cell, and a energy storage system. This paper explains and simulates the micro grid components in terms of accuracy and efficiency of having a system model based on the costs of fuel as well as operation and maintenance. For operational efficiency, the objective function in a diesel generator consists of the fuel cost function similar to the cost functions used for the conventional fossil-fuel generating plants. The wind turbine generator is modeled by the characteristics of variable output. The optimization is aimed at minimizing the cost function of the system while constraining it to meet the customer demand and safety of micro grid. The operating cost in fuel-cell system includes the fuel costs and the efficiency for fuel to generate electric power. To develop the overall system model gives a possibility to minimize of the total cost of micro grid. The application of optimal operation can save the interruption costs as well as the operating costs, and improve reliability index in micro grid.

• Agricultural and Biosystems Engineering
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• v.6 no.2
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• pp.59-64
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• 2005

In the study, the cone index, the cohesion and the internal resistant angle of soil were measured before and after tillage in order to suggest relative improvement in soil properties. The tillage methods tested in the study were five combinations of plow and rotary tillage operation and the experiments were performed on five selected test fields. The maximum tillage depth was 20 cm under the ground. The CIs for all the tillage operations were improved in comparison with those before tillage. The best combination of tillage operations for improving the CIs of soil was one plow operation followed by one rotary. After applying the tillage operations, the internal resistance angle reduced by 7-8 degree and the cohesion decreased up to about $1N/cm^2$ in comparison with those before tillage. We concluded that the cone index, the cohesion and the internal resistant angle of soil could be used as measures for representing the relative degree of tillage for a specific tillage operation. In addition, the study was useful as a basic research tool for developing an decision making system that determines an optimal tillage method with soil properties.

• The Journal of Information Technology and Database
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• v.2 no.2
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• pp.87-109
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• 1995

The index file has been used a access database records effectively. The join operation in a relational database system requires a large execution time, especially in the case of handling large size tables. If the indexes are available on the joining attributes for both relations involved in the join and the join selectivity is relatively small, we can improve the execution time of the join operation. In this paper. we investigate the performance trade-offs of parallel index-based join algorithms where different indexing schemes are used. We also present a comparison of our index-based parallel join algorithms with the hash-based parallel join algorithm.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.12-14
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• 2006

This paper presents an vulnerability index for hidden failure of protective relays in transmission system. The bad influence can be quantized by an vulnerability index. When there is mis-operation, no-operation or mis-setting, power flow can be quantized by an index. According to the index, relays can be resetting. So the wide area blackout can be prevented.

• Journal of Chest Surgery
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• v.21 no.6
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• pp.957-969
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• 1988

There is tendency of increasing number and decreasing age of patients who are indicated for Rastelli operation for their cyanotic congenita heart disease. So there is the need to find the creiterion which saves the patients from early postoperative hemodynamic disturbances. We reviewed the 26 patients who had been performed Rastelli operation at Seoul national University hOipital from January 1981 to June 1988. mean age of the patients was 7.8 $\pm$ 3.4 years (range 2.5-1.5 years), mean body surface area(BSA) 0.79 $\pm$ 0.25 $m^{2}$(range 0.49-1.51 $m^{2}$) and mean hematocrit 57.95 $\pm$ 12%(range 48-80%). We diveded these patients into survived group and died group before postoperative 72 hours, and analysed preoperative arterial oxygen saturation($SaO_{2}$), the ratio of diameter of fight pulmonary artery to ascending aorta(RA:/AA), the ratio of both right and left pulmonary artery diameter to descending thoracic aorta(RPA+LPA/DTA), pulmonary artery index(PA index), cardiopulmonary bypass time, aorta cross-clamping time, postoperative perfusion state and total amount of dopamine infused postoperatively. The results showed that RPA+LPA/DTA and PA index were statistically significatn factors to influence early postoperative cardiac death rate (P<0.05). Especially there were good linear correlations between PA index(X) and perpheral perfusion index(Y)(Y = -1.15 + 0.02 X, r = 0.86, P<0.01) and between PA index(X) and total amount of dopamine infused before postoperative 72 hours(mg/kg, Y)(Y = 61.94 - 0.15 X, r = - 0.80, P<0.01). Also there were tendencies that the higher RPA + LPA/DTA(Y), the betterperipheral perfusion (X) and the lower need of dopamine(X), but no statistical significance. (Y = 0.78 + 1.60 X, r = 0.49, P>0.05) And the discrimant analysis showed that patients with PA index over 221 $mm^{2}$/BSA could undergo correction with 25 per cent of error rate. In conclusion, early postoperative hemodynamic states could be predicted by preoperatively measured PA index, and which can be used as a criterion for Rastelli operation performed on cyanotic congenital heart disease.

• Journal of Drive and Control
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• v.19 no.4
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• pp.29-35
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• 2022

In this paper, we developed a workload index for monitoring the durability test using operation information of an excavator. First, the acceleration and cylinder pressure were selected as load factors by analyzing operation data. Through load correlation analysis according to each load factor, Root Mean Square (RMS) and Work Load Range (WLR) were respectively derived as a load feature representing mechanical load. In addition, the workload index was used to quantify load features. For applying the workload index to monitoring, a real-time monitoring system consisting of sensors and embedded controller was installed on the excavator and the system was integrated with a remote monitoring environment using a wireless network. Results of load monitoring and analysis verified that the developed workload index was effective from the viewpoint of the relative comparison of the workload.