• 한국유기농업학회지
• /
• 제24권3호
• /
• pp.337-353
• /
• 2016

The objective of this study is to analyze the DEA efficiency of the environment-friendly agricultural districts and zones. There are political inefficiency in districts and zones with 45.3% and 85.0%. It mainly results from scale efficiency than pure technical efficiency. There are 10 efficient zones, while 34 decreasing return to scale ones. Meanwhile, districts mostly have increasing return to scale with 97.9%. The results of this study is meaningful to re-construct the project based on the environment-friendly agricultural production.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.1172-1175
• /
• 2001

Recently, vector control without a speed sensor for an inverter induction motor system has been developed. In this paper describes the vector control system estimates rotor speed based on FMRAS(Flux Model Reference Adaptive System). Because of improving the initial condition and drift problem by pure integrator is eliminated, we can be expected to rapid responsibility of the speed estimation. The stability of speed estimator is proved on the basis of hyperstability theory. Proposed control system used TMS320C31 DSP for high speed processing. The effectiveness of the proposed system is verified by simulation and experimental results. This result shows that the highly characteristic speed estimation and robust character of load regulation.

• The Journal of the Acoustical Society of Korea
• /
• 제20권2E호
• /
• pp.25-29
• /
• 2001

In this paper, we propose a new method for selecting the threshold on wavelet packet denoising. In selecting threshold, the method using median is not efficient. Because this method can not recover unvoiced signal corrupted by noise. So we partition a speech signal corrupted by noise into the pure noise section and voiced section using autocorrelation and entropy. The autocorrelation and entropy can reflect disorder of noise. The new method yields more improved denoising effect. Especially unvoiced signal is very nicely reconstructed, and SNR is improved.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.157-160
• /
• 2008

Improved properties of second electron emission was evaluated by assemble of 4 inch PDP panel. MgO protection layers were deposited and examined by using both pellets made of extremely pure MgO single crystals and sintered pellets using MgO nano powders. $\gamma$ coefficients higher than 0.11 were obtained from the panel by adopting dopant-controlled MgO single crystals. Especially the MgO layer deposited by sintered pellets made of nano powders showed the higher $\gamma$ coefficients at the operating voltage above 200 volts.

• 한국유기농업학회지
• /
• 제25권4호
• /
• pp.679-697
• /
• 2017

This study analyzes an economic efficiency of environmental friendly farm and conventional farm using the data envelopment analysis (DEA). We compare the economic efficiency of Environmental Friendly farm and Conventional farm. We also analyze the effects of some explanatory variables on allocative efficiency (AE), pure technology efficiency (PTE) and scale efficiency (SE). In the case of strawberries farm, environmental friendly farm has higher overall efficiency (OE) than conventional farm. But tomatoes farm has higher overall efficiency (OE) than conventional farm. And We measure returns to scale of farms. Most strawberries and tomatoes farms showed Increasing to Scale (IRS).

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2000년도 춘계학술대회논문집
• /
• pp.1338-1343
• /
• 2000

This paper deals with an application of Magneto-Rheological (MR) fluid to a small size mount for precision equipment of automobiles. MR fluid is known as a class of functional fluids with controllable apparent viscosity of fluid by the applied magnetic field strength. A typical MR fluid is a suspension where pure iron particles of $1{\sim}20mm$ in diameter are dispersed in a liquid such as mineral oil or silicone oil, at the concentration of $20{\sim}40$ vol%. Electro magnetic coil is installed at the bottom of a variable-damping mount filled with MR fluid, and its performance was investigated experimentally. Furthermore, the properties of the MR Mount on experimental Study were explained analytically by mechanical model of the MR mount.

• Journal of Mechanical Science and Technology
• /
• 제19권spc1호
• /
• pp.377-387
• /
• 2005

The equations of motion of two-wheeled vehicles, e.g. bicycles or motorcycles, are developed by using Lagrange's equations for quasi-coordinates. The pure rolling constraints between the ground and the two wheels are considered in the dynamical equations of the system. For each wheel, two nonholonomic and two holonomic constraints are introduced in a set of differential-algebraic equations (DAE). The constraint Jacobian matrix is obtained by collecting all the constraint equations and converting them into the velocity form. Equilibrium, an algorithm for searching for equilibrium points of two-wheeled vehicles and the associated problems are discussed. Formulae for calculating the radii of curvatures of ground-wheel contact paths and the reference point are also given.

• 한국통신학회논문지
• /
• 제38A권11호
• /
• pp.976-978
• /
• 2013

본 논문은 LoS(line-of-sight) 환경에서 두 개의 선형편파 안테나를 사용하는 데이터 통신 기법을 다룬다. 편파안테나의 물리적인 각도가 채널용량과 오류성능에 미치는 영향을 분석한다. 두 가지 관점에서의 최적 안테나 각도가 상이함을 보이며, 두 각도에 대해 채널용량 및 오류성능을 비교한다.

• The Korean Journal of Pain
• /
• 제9권1호
• /
• pp.268-270
• /
• 1996

We treated a patient who experienced motor weakness and sensory change on left lower extremity after thoracic sympathetic ganglion block with pure alcohol. The following factors were suspected of contributing to neurologic complication: (1) ischemia of spinal cord, (2) infection, (3) re-expression and aggravation of pre-existing neurologic disease, (4) improper position. Patient spontaneously recovered from neurologic complication with conservative therapy.

• 한국건축시공학회지
• /
• 제13권1호
• /
• pp.1-9
• /
• 2013

There has recently been a great deal of research into the appropriate building materials for eco-friendly construction. In the field of earth architecture, there have been walls made of pure earth or with rammed earth including a small amount of cement. The purpose of the study is to investigate the possibility increasing compressive strength through a more eco-friendly composition by using Hwangtoh binder rather than cement to increase the strength performance of rammed earth. It was found that the more the ratio of binder was increased, the more the strength was increased, but enhancement did not increase noticeably in the lower part that did not compact completely, and proper height to pour earth is 200 mm. When stone dust was added, compressive strength was lower than when adding fine aggregate and coarse aggregate, but a finer surface texture was provided.