• Journal of the Korean Society for Precision Engineering
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• v.24 no.3 s.192
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• pp.100-107
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• 2007

A internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with circular shape, while the inner rotor profile is determined as conjugate to the other. The topic of this paper is the design of a new rotor, which is based on specific performance as different types depending on the shape of the lobe of the outer rotor. First, the design of internal lobe pumps with circular, elliptical, and their combined lobe profiles is considered. The latter is a new type of lobe profile with special shape whose curvature follows a definite function. Then we introduce the performance indexes used for the comparison. Some of these indexes, such as flow rate and flow rate irregularity, are commonly used for the comparison, while specific slipping is particularly suitable in this case. It is possible to notice that the circular and elliptical type is comparable to the circular one or the elliptical one in terms of flow rate irregularity, but has improved performance in terms of specific slipping. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• The Journal of the Acoustical Society of Korea
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• v.33 no.3
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• pp.200-209
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• 2014

In this paper, we present a general model for synthetic transmit focusing method using plane waves (STF-PW) of which the properties are investigated through mathematical analysis and compared with those of the conventional focusing method. The analysis results show that STF-PW produces non-diffracting beams in the sense that their main lobe widths do not change with depth. We also present a method for synthesis of plane waves to obtain a desired main lobe width while preventing grating lobe generation and a method for broadening the region over which the non-diffracting property is maintained. The proposed model and analysis results were validated through computer simulations.

• ETRI Journal
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• v.33 no.6
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• pp.849-856
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• 2011

This research introduces three new fractal array configurations that have superior performance over the well-known Sierpinski fractal array. These arrays are based on the fractal shapes Dragon, Twig, and a new shape which will be called Flap fractal. Their superiority comes from the low side lobe level and/or the wide angle between the main lobe and the side lobes, which improves the signal-to-intersymbol interference and signal-to-noise ratio. Their performance is compared to the known array configurations: uniform, random, and Sierpinski fractal arrays.

• Tuberculosis and Respiratory Diseases
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• v.65 no.6
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• pp.532-536
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• 2008

We report on a case of a patient with laryngo-tracheobronchial amyloidosis who complained of cough, sputum, and hoarseness. A chest X-ray showed consolidation in the right middle lobe. A chest CT scan showed diffuse, irregular narrowing of the tracheobronchial tree and atelectasis of the right middle lobe, with calcification of bronchial wall. Bronchoscopic findings were multinodular submucosal thickening of the right vocal cord, and yellowish multinodular submucosal thickening from the lower trachea through both main bronchi, as well as the lingular division of the left upper lobe, the right middle lobe, and the right lower lobe. The right middle lobe bronchus was nearly obstructed. The diagnosis of amyloidosis was made by multiple ronchoscopic biopsies on the right vocal cord and both bronchi. Pathologic findings were characteristic apple-green birefringence under polarized microscopy with Congo-red stain. The patient had no evidence of systemic amyloidosis. The patient is under conservative symptomatic treatment.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.131-134
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• 2000

음성신호처리에서 스펙트럼 분석은 매우 중요하다. 하지만 스펙트럼 분석을 위해서 사용되는 윈도우에 의해 생기는 누설에러지 때문에 음성신호의 스펙트럼 정보가 왜곡된다. 본 논문에서는 스펙트럼 분석 시 발생되는 창함수 사용에 의해 생기는 누설에너지를 최소화하기 위한 새로운 창함수를 제안하고자 한다. 그 형태는 전체 창함수크기의 반을 방형창으로 나머지 반을 해밍창으로 하고 창의 처음 부분은 $\pm$20표본에서 영점을 찾아주는 것이다. 이 창함수의 특징은 신호분석에 있어서 왜곡은 크지만 그 형태에 있어서 가장 이상적인 방형창함수의 장점과 side lobe가 작아 비교적 왜곡이 적은 해밍창함수의 장점을 취한 것이라 하겠다. 실제 음성 신호에의 적용에 있어서 방형창과 해밍창의 적용비는 신호의 종류 및 용도에 따라 달리할 수 있다. 제안한 창함수는 해밍창함수 보다는 좁은 main lobe 특성으로 음성신호의 단구간 스펙트럼 분석시 음성의 빠른 변화특성을 적절히 보여줄 수 있고 방형창보다는 side lobe의 영향을 줄일 수 있다.

• Journal of Chest Surgery
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• v.30 no.8
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• pp.843-846
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• 1997

Congenital bronchial atresia is one of the rare bronchopulmonary anomalies which is thought to be caused by a vascular insult of uncertain timing during fefal development. It is defined as an anomaly which does not have communication between a segmental or lobar bronchus a'nd the main airway. Because of the collateral ventilation, almost all of these cases show hyperlucency of the involved segment or lobe in chest roentgenogram. We report an extremely rare case of congenita bronchial atresia with collapse of the right upper lobe which was treated by surgical resection.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.738-746
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• 1999

In this paper, a microstrip $18\times2$ dual beam array antenna is designed at 10 GHz. The radiating element is an aperture-coupled patch, and it is analyzed by the transmission line model. The feed is a tapered parallel-series type to reduce the side lobe level. To obtain dual beam at $\pm45^{\circ}$, The difference in phase excitation between the elements is $180^{\circ}$. In conclusion, the side lobe level is 25 dB, and the beam width $8^{\circ}$with two main lobes at $\pm44.5^{\circ}$.

• Structural Engineering and Mechanics
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• v.28 no.3
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• pp.335-352
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• 2008

Continuous operation of test and measurement is a new operating technique in the petroleum exploitation, which combines perforation with test and measurement effectively. In order to measure the original pressure of stratum layer exactly and prevent testing instrument from being impaired or damaged, a suitable shock absorber is urgently necessary to research. Based on the attempt on the FEM analysis and experiment research, a new shock absorber is designed and discussed in this paper. 3D finite element model is established and simulated accurately by LS-DYNA, the effect and the dynamic character of the shock absorber impact by half sinusoidal pulse force under the main lobe frequency are discussed both on theoretics and experiment. It is shown that the new designed shock absorber system has good capability of shock absorption for the impact load.

• Journal of the Korea Society of Computer and Information
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• v.16 no.9
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• pp.155-162
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• 2011

It is using to incident angle estimation technique in order to target estimation in radar. This paper was estimated incident angle estimation for target using adaptive array incident angle and single look error incident angle estimation technique. We estimated signal incident angle of target to removal main lobe and side lobe to adaptive array incident angle technique. It is difficult to correctly target estimation because single look technique increase direction error of signal incident angle. In order to receive a desired target signal must be not almost look error between signal incident angle and look angle. we had decreased to occur a look error using delay time and single look condition to calculation a covariance when incident angle estimate. Through simulation, we show that the proposed incident angle estimation technique improves the performance of target estimation compared to previous method.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.53-59
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• 2018

In this study, a new design method is developed to optimize the structure of an underwater sparse array sensor. The purpose of this research is to design the structure of a sparse array that has the performance equivalent to a fully sampled array. The directional factor of a sparse planar array is derived as a function of the structural parameters of the array. With the derived equation, the structure of the sparse array sensor is designed to have the performance equivalent to that of the fully array sensor through structural optimization of the number and location of transmitting and receiving elements in the array. The designed sparse array sensor shows beam patterns very close to those of the fully array sensor in terms of PSLL (Peak Side Lobe Level) and MLBW (Main Lobe Beam Width), which confirms the effectiveness of the present optimal design method. Further, the validity of the analytic beam patterns is verified by comparing them with those from the FEA (Finite Element Analysis) of the optimized sparse array structure.