• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 추계학술대회 논문집
• /
• pp.647-648
• /
• 2012

• 한국의류산업학회지
• /
• 제12권6호
• /
• pp.745-754
• /
• 2010

This study is to find return factors when modern consumers purchase goods from an internet shopping mall and then to analyze the characteristics of complaints act and information search behavior. Subjects of research are 245 men and women, who have experience with more than one return in internet fashion shopping mall, in their twenties. The data were analyzed by using Factor analysis, Cronbach's analysis, one-way ANOVA, Duncan test as a post identification, Pearson's correlation analysis and multiple regression analysis. The results of this study are that male and female consumers in their 20s are mainly aware of the return factors: impulse buying, product status, deliver service, service after purchase, hype and comfortableness. And complains behavior often conduct public action, private action, nonaction. Information search behaviors for risk reduction when they purchase are product comparison, oral information search, neutral marketing information search, and service information search. The return factor from the internet fashion shopping had the greatest impact on public action and deliver services factor was a big complaint. In addition, impulse buying & Hype affect private action and non-action is influenced by impulse purchase. The consumer types by the return factors in internet fashion shopping mall are classified into the return group by deliver service, the return group by complex factors, and the return group by product status. Furthermore, there are significant differences in complaining behavior among these groups. In the information search behavior for reduction of risk factors, the return group by complex factors did more active information search behavior than the other groups. The return group by deliver service searched oral information and the return group by product status explored the neutral marketing information.

• 대한전자공학회논문지TC
• /
• 제46권3호
• /
• pp.32-39
• /
• 2009

본 논문은 초광대역 임펄스를 이용한 지반탐사 영상레이더 시스템 (Ground Penetrating Image Radar; GPIR) 설계에서 수직심도의 해상도를 높이기 위한 시간영역 관점에서의 최적화 설계방법을 제시하였다. 시스템의 핵심 부분인 임펄스 발생원 및 초광대역 안테나에 대하여 시간영역에서의 해석 기법을 제시하였고, 시뮬레이션에 의해 최적 설계 파라미터를 설정하였다. 특히, 임펄스 신호의 파형을 정형화하여 임펄스 신호의 스펙트럼 효율을 높였으며, 초광대역 안테나로는 U자형 평판형 다이폴 안테나를 사용하였다. 제안된 안테나는 반사체를 사용하여 외부 잡음을 차단하였고, 지중과의 신호 결합을 개선하였다. 또한 시스템의 성능을 열화시키는 안테나에 의한 떨림을 제거하기 위해, 저항을 사용하였고, 송수신 안테나는 시간영역 시뮬레이션을 통하여 최적화 하였다. 지중 매질의 영상화를 위해 마이그레이션을 기법을 사용하였으며, 지면의 영향 등에 의한 수신된 펄스의 왜곡 현상은 시간영역에서의 잡음 및 신호 왜곡 저감 기법을 사용하여 성능을 개선하였다. 최적화된 설계 방법의 평가를 위하여, 지중 매설물 탐지용 레이더 시제품을 개발하였고, 성능 시험을 위한 시험장을 활용하였다. 측정 결과 수직 심도는 이론적 인 해 상도만큼 우수한 성능을 보였다.

• 전기학회논문지
• /
• 제63권4호
• /
• pp.551-558
• /
• 2014

Baseline drift reduction and removal of power line noises in electrocardiogram are often necessary to avoid the distortions in extracting the fiducial features. With this aim, the multirate digital filtering algorithm is suggested to design and implement Finite Impulse Response or Infinite Impulse Response Filter by changing the sampling rate with omitting or interpolating intermediate ECG data. After the experimental simulations performed, we can conclude the fact that we can suppress the baseline wander and power line disturbances in ECG signal with reducing the computational complexities in which we do not keep the original and high sampling frequency.

• 조명전기설비학회논문지
• /
• 제29권4호
• /
• pp.95-101
• /
• 2015

This paper presents experimental results about characteristics of soil discharge as a function of moisture content when the $1.2/50{\mu}s$ lightning impulse voltage is applied. The laboratory experiments, for this study, were carried out based on factors affecting the transient behavior in soils. The electrical breakdown in soils was measured over a 0-6% range of moisture content for sands and a 0-4% range of moisture content for gravels. Needle-plane electrode systems was used As a result, the conduction current prior to ionization growth in dry soil is a little, but it in wet soil is increased with the applied voltage because the wet soil particles act as conductors. The soil impedance curves show an abrupt reduction just after breakdown. The general tendency measured in different soils is that the higher the water content, the lower the breakdown voltage and the shorter the time-lag to breakdown.

• Wind and Structures
• /
• 제7권6호
• /
• pp.421-447
• /
• 2004

This paper presents a time domain approach for predicting buffeting response of long suspension bridges under skew winds. The buffeting forces on an oblique strip of the bridge deck in the mean wind direction are derived in terms of aerodynamic coefficients measured under skew winds and equivalent fluctuating wind velocities with aerodynamic impulse functions included. The time histories of equivalent fluctuating wind velocities and then buffeting forces along the bridge deck are simulated using the spectral representation method based on the Gaussian distribution assumption. The self-excited forces on an oblique strip of the bridge deck are represented by the convolution integrals involving aerodynamic impulse functions and structural motions. The aerodynamic impulse functions of self-excited forces are derived from experimentally measured flutter derivatives under skew winds using rational function approximations. The governing equation of motion of a long suspension bridge under skew winds is established using the finite element method and solved using the Newmark numerical method. The proposed time domain approach is finally applied to the Tsing Ma suspension bridge in Hong Kong. The computed buffeting responses of the bridge under skew winds during Typhoon Sam are compared with those obtained from the frequency domain approach and the field measurement. The comparisons are found satisfactory for the bridge response in the main span.

• Journal of Electrical Engineering and Technology
• /
• 제4권1호
• /
• pp.98-105
• /
• 2009

This paper presents the characteristics of soil ionization for different water contents, and the parameters associated with the dynamic properties of a simple model grounding system subject to lightning impulse currents. The laboratory experiments for this study were carried out based on factors affecting the soil resistivities. The soil resistivities are adjusted with water contents in the range from 2 to 8% by weight. A test cell with a spherical electrode buried in the middle of the hemispherical container was used. As a result, the electric field intensity $E_c$ initiating ionization is decreased with the reduction of soil resistivities. Also, as the water content increased, the pre-ionization resistance $R_1$ and the post-ionization resistance $R_2$ became lower with increasing current amplitude. The time-lag to ionization $t_1$ and the time-lag to the second current peak $t_2$ at high applied voltages were significantly shorter than those of low applied voltages. It was found that the soil ionization behaviors are highly dependent on the water content and the applied voltage amplitude.

• 반도체디스플레이기술학회지
• /
• 제11권2호
• /
• pp.33-38
• /
• 2012

The wafer positioning robot in the semiconductor industry is required to operate at high speed for the improvement of productivity. The residual vibration caused by the high speed of the wafer positioning robot, however, makes the life of the robot shorter and the cycle time longer. In this study, the input shaping and the path of the system are designed for the reduction of the residual vibration and the improvement of the cycle time. The followings are the process for the reduction and the improvement; 1) System modeling of the wafer positioning robot, 2) Verification of dynamic characteristics of the wafer positioning robot, 3) Input shaping plan using impulse response reiteration, 4) Simulation test using SIMULINK program, 5) Analysis of result.

• 전자공학회논문지
• /
• 제51권2호
• /
• pp.207-213
• /
• 2014

본 논문에서는 임펄스 잡음을 제거하는 수정된 미디언 필터를 제안한다. 다단계를 기반으로 하는 제안 방법은 먼저 잡음 영상에서 잡음과 화소를 분리하고 잡음으로 판단된 화소를 미디언 필터링한다. 이때 필터링에 사용하는 주변 화소들을 에지에 따라 방향을 조절하여 필터링하는 선형필터링 한 값으로 대체한다. 따라서 제안하는 방법은 에지를 유지할 뿐 아니라 일정한 지역에서 잡음을 효과적으로 제거한다. 실험결과, 제안하는 방법이 기존 수정된 미디언 필터 보다 향상된 결과를 보인다.

• 한국기계가공학회지
• /
• 제15권5호
• /
• pp.125-130
• /
• 2016

A low-recoil direct gun is useful in reducing the fire impulse generated by using a traditional shell. To apply a control equation to an AMESim Model, we have formulated a control equation for a recoil mechanism from the free object diagram. By modeling this equation, we have been able to compare the recoil distance and recoil force of a low-recoil direct gun. Here, we can analyze the recoil characteristics between traditional direct guns and low-recoil direct guns with perforated muzzle brakes. It is possible to mount a low-recoil direct gun with a perforated muzzle brake on a lightweight tracked vehicle by reducing its fire impulse.