• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.519-520
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• 2006

The aim of this study was biomechanical analysis of shelf operation in patients with dysplastic hip joint by finite element contact analysis. Two dimensional CT images were used to construct the finite element models to analyze the contact pressure, and the 3D expansion of the Ninomiya's method was used in the calculation of the resultant force in the hip joint. The surgery recovered the center-edge angles to the normal anatomical range and increased the contact areas in two patients. The maximum contact pressures and von-mises stresses were decreased. The present study provides the biomechanical guideline of optimal surgical parameters to maximize the surgical efficiency and the clinical outcomes in dysplastic hip joint using the shelf operation.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.677-681
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• 2005

This Paper presents a 6 pulse shift operation control mode of current-source-inverter to make improvement of efficiency and to reduce the frequency of inverter switching for photovoltaic generation system using PWM current-source-inverter. This system is connected solar cell energy directly without using a storage cell. The proposed circuit can maintain maximum voltage of photovoltaic generation of take advantage of six Buck-Boost converter and a full-bridge inverter determines the polarity of AC output. That is controlled by using digital signal processor TMS320F2812 for operation about a 6 pulse shift operation control of current-source-inverter, and it is verified through the experimental results.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.568-574
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• 2013

A semi-pilot biofilter packed with media with immobilized Thiobacillus sp. IW and return sludge, was operated under various operating conditions in order to treat malodorous waste air containing both hydrogen sulfide and ammonia which are major air pollutants emitted from composting factories and many publicly owned treatment works (POTW). At the incipient and middle stages of a semi-pilot biofilter operation, the hydrogen sulfide-removal efficiency behaves regardless of an inlet-load of ammonia. However, the ammonia-removal efficiency decreased as an inlet-load of hydrogen sulfide increased. Nevertheless, at the final stage of the semi-pilot biofilter operation, the ammonia-removal efficiency was not affected by the increase of hydrogen sulfide-inlet load. It is attributed to that a serious acidification of semi-pilot biofilter-media did not occur due to continuous injection of buffer solution at the final stage of the semi-pilot biofilter operation. When both hydrogen sulfide and ammonia contained in malodorous waste air were treated simultaneously by semi-pilot biofilter, the maximum elimination capacities of hydrogen sulfide and ammonia turned out to be ca. 58 and $30g/m^3/h$, respectively. These maximum elimination capacities were estimated to be ca. 39 and 46% less than those for lab-scaled biofilter-separate elimination of hydrogen sulfide and ammonia, respectively. Thus, for the simultaneous biofilter-treatment of hydrogen sulfide and ammonia, the maximum elimination capacity of ammonia decreased by 7% more than that of hydrogen sulfide.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.969-978
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• 2016

Around the world are increasing the demand for ESS. Currently, the domestic is expected to benefit by operating ESS. In the domestic, it is expected to benefit from operations of the installed ESS because of the introduction of ESS less capacity. However ESS capacity to the maximum profit occurs is unknown. ESS is different from the charge-discharge characteristics and the reserve to replace, depending on the application. Therefore, it should be established in accordance with the ESS optimal capacity according to the purpose used because it can maximize the quality and efficiency of the electric energy. To the ESS optimal capacity estimation by the purpose used, It should compare the investment cost caused by ESS facility installation and operation cost caused by operating ESS. In this paper, the operation mathematical model for estimating marginal operation costs established. In operation mathematical model, operating cost is considered fuel cost and no-load cost start-up cost. Because no-load cost and start-up cost are not related to cost and power plant output, there are expressed an integer variable costs as a step function.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.435-440
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• 2011

This paper propose the method of constructing the highly efficiency adder and multiplier systems over finite fields. The addition arithmetic operation over finite field is simple comparatively because that addition arithmetic operation is analyzed by each digit modP summation independently. But in case of multiplication arithmetic operation, we generate maximum k=2m-2 degree of ${\alpha}^k$ terms, therefore we decrease k into m-1 degree using irreducible primitive polynomial. We propose two method of control signal generation for the purpose of performing above decrease process. One method is the combinational logic expression and the other method is universal signal generation. The proposed method of constructing the highly adder/multiplier systems is as following. First of all, we obtain algorithms for addition and multiplication arithmetic operation based on the mathematical properties over finite fields, next we construct basic cell of A-cell and M-cell using T-gate and modP cyclic gate. Finally we construct adder module and multiplier module over finite fields after synthesizing ${\alpha}^k$ generation module and control signal CSt generation module with A-cell and M-cell. Next, we constructing the arithmetic operation unit over finite fields. Then, we propose the future research and prospects.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.239-247
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• 1991

This study was conducted to investigate the feasbility of continuously variable V-belt transmission(CVVT) as automatic power transmission system of combine harvesters. An experimental set-up for testing the performance of CVVT and the automatic transmission system was designed and used to analyze the power transmission characteristics of CVVT. The transmission efficiency of CVVT was increased logarithmically with increase of the load of driven shaft, but was not affected by the speed ratios of transmission. More than 80% of transmission efficiency was obtained in the 25N-m load and more of driven-shaft, and the maximum efficiency was 88~91%. When rapid speed change of the CVVT was attempted, the speed of driven shaft was stabilized within about 0.4 seconds after shift operation in both cases of increasing and decreasing of the speed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.9
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• pp.431-436
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• 2005

This paper studies a novel boost DC-DC converter operated high efficiency for discontinuous current mode (DCM) control. The converter worked in DCM eliminates the complicated circuit control requirement, reduces a number of components, and reduces the used reactive components size. In the general DCM converter, the switching devices are turned-on the zero current switching (ZCS), and the switching devices must be switched-off at a maximum reactor current. To achieve the zero voltage switching (ZVS) at the switching turn-off, the proposed converter is constructed by using a new loss-less snubber circuit. Soft-switched operation of the proposed boost converter is verified by digital simulation and experimental results. A new boost converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of boost DC-DC converter is high.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.79-83
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• 1997

The inverter fed BLDC(Brushless DC) motor has been increasingly applied to industry and home appliances due to the advance of power electronics and permanent magnet technology, and its high efficiency and good acoustic noise characteristics. The BLDC motor and drives, however, require the rotor position sensors that may cause some problems such as the high cost and space. In this paper, sensorless algorithm for an interior permanent magnet BLDC motor is proposed. The maximum torque per ampere operation with advance angle considering load torque and speed was simulated and verified through the experiment.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.4
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• pp.16-25
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• 1997

This paper shows a SDRAM opeating in 200MHz clock cycle which it use data interleave and pipelining for high speed operation. We proposed NdC (Negative DEaly circuit) to improve clock to access time(tAC) characteristics, also we proposed low power WL(wordline)driver circit and high efficiency VPP charge-pump circit. Our all circuits has been fabricated using 0.4um CMOS process, and the measured maximum speed is 200Mbytes/s in LvTTL interface.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.6
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• pp.686-695
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• 1988

An algorithm and a computer program were developed for the operational simulation of office building cooling system. Using this computer program, the following results were obtained. ${\bullet}$ There is a critical number of coil rows in AHU with which the cooling system can be operated in maximum efficiency. ${\bullet}$ Energy conservation can be achieved in an office building through TAB(Testing Adjusting and Balancing) of zone air volumes.