• Journal of electromagnetic engineering and science
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• 제12권3호
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• pp.216-222
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• 2012

This paper presents a single-pole eight-throw switch, based on an eight-way power divider, using substrate integrate waveguide(SIW) technology. Eight sectorial-lines are formed by inserting radial slot-lines on the top plate of SIW power divider. Each sectorial-line can be controlled independently with high level of isolation. The switching is accomplished by altering the capacitance of the varactor on the line, which causes different input impedances to be seen at a central probe to each sectorial line. The proposed structure works as a switching circuit and an eight-way power divider depending on the bias condition. The change in resonant frequency and input impedance are estimated by adapting a tapered transmission line model. The detailed design, fabrication, and measurement are discussed.

• 전기학회논문지P
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• 제64권3호
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• pp.146-152
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• 2015

In this paper, we propose a boost DC-DC converter using a modification of the passive auxiliary resonant snubber circuit with a DC-DC converter in a typical active auxiliary resonant snubber-bridge inverter. The proposed boost DC-DC converter is small compared to the DC-DC converter according to the soft-switching scheme that requires a general auxiliary switch by realizing the soft switching operation as a DC-DC converter which does not require an auxiliary switch. It is light-weight, switch the turn-on and turn-off switching loss at the time of the superposition of the voltage and current is extremely small, so small. And the reduction of the surge voltage and current of the switch. In addition, the proposed boost DC-DC converter has a high efficiency over a wide load characteristics change area than conventional hard switching PWM boost converter using an RC snubber loss.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.5201-5206
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• 2014

본 논문에서는 블루투스 통신이 가능한 스마트 전등 스위치를 이용하여 안드로이드 스마트 폰을 이용한 전등 스위치 원격 제어를 구현 하였다. 스마트 전등 스위치는 임베디드 보드와 무선 통신을 이용하여 데이터를 송/수신하여 임베디드 보드에서 데이터를 종합 수집, 가공 하여 이 데이터를 다시 스마트폰과 무선통신을 이용하여 데이터를 송/수신 한다. 임베디드 보드를 게이트웨이로 이용함으로써 추후 추가 될 수 있는 센서들의 유연성을 보장 하였다. 이는 현재 신축 아파트 및 건물에서 서비스 중인 기능이지만, 이를 지원하지 않는 기존 가정에서도 스위치만 교환하여 사용이 가능하므로 사용자의 편의성과 시스템의 유연성을 보장한다.

• 한국전자통신학회논문지
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• 제10권2호
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• pp.211-218
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• 2015

본 논문에서는 클라우드 컴퓨팅 서비스를 위한 가상 네트워크 구축에 필요한 중요 구성 요소 중의 하나인 가상스위치를 Intel DPDK(Data Plane Development Kit)를 이용하여 구현하고 DPDK에서 지원하는 가속화 가상스위치의 기능을 테스트 및 검증하였다. 최근 사물인터넷 등에서와 같이 지능형 IT 시스템들의 인터넷 접속을 통한 새로운 정보 서비스 플랫폼의 출현과 그에 대한 활용 및 응용 서비스를 기업 비즈니스에 적용하고자 하는 기업이 많아지고 있다. 기업들은 매우 빠른 소비자 환경변화에 민첩하게 대응할 수 있는 신규 서비스에 대한 사용자 입장에서의 클라우드 컴퓨팅 활용 측면으로 적은 비용으로 신규 서비스를 빠른 시일 내에 적용할 수 있다. 본 연구에서는 창조적 서비스 사업에 활용할 수 있는 스마트 클라우드 플랫폼 서비스를 효율적으로 구현하기 위한 고속 가상스위치를 Intel DPDK를 이용하여 구현하고 그의 기능 검증에 대한 연구를 수행하였다.

• 아태비즈니스연구
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• 제12권3호
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• pp.193-212
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• 2021

Purpose - This study investigates the effect of auditor change on client firm's accounting (financial statement) comparability. Design/methodology/approach - The comparability of accounting information is measured by the difference in accruals between the two firms. Additionally, the study uses earnings-stock return relationship as another proxy of accounting comparability. In particular, the paper examines whether there is a systematic difference between initial audit years and the other years with respect to the client firm's accounting comparability. Moreover, current study tests how changes in auditor size or industry expertise before and after the switch of auditors affect the accounting comparability. Findings - The results show that the level of accounting comparability is lower in the year of auditor change than in the other years. Furthermore, this lower level of comparability is derived by the observations that switch their auditors from non-Big4 to non-Big4 or from non-specialist to non-specialist. These results are consistent when accounting comparability is measured by different proxies. Research implications or Originality - The findings of this study provide important policy implications for the regulations related with auditor selection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.365-367
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• 2003

In this study, we studied the change plan essentially used for improving the existing railroad signal system. For mixed installation with the existing equipment by introducing new equipment in the city railroad currently operated, it is required to establish a plan depending on the change and to present a plan for change. For the change, since it is necessary to classify ground equipment and onboard equipment and change must be carried out considering performance and functions of each equipment, we classified and studied each equipment for plans of change.

• 한국생활과학회지
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• 제19권5호
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• pp.845-855
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• 2010

This study examined the variables that affect whether consumers change broadband internet services by examining their past experiences and intention to switch carriers by targeting consumers who have switched broadband internet service providers. Among adult consumers who intended to switch broadband providers, 341 people who had experience were subject to logistic regression analysis using SPSS for Windows ver. 17.0 to examine frequencies, means, percentages, and factor analysis. The following results were revealed. First, the targets were currently using broadband internet service in the order Company S > Company L > Company K > others. Excluding the others, Company K had the most conversions (from 96 to 78), followed by Company S (from 107 to 97), and Company L (from 43 to 97), which more than doubled the number of subscribers. The reasons for switching carriers in the past were as follows: for Company K, consumers switched to other companies because of unsatisfactory fee services; for Company S, consumers switched to other companies because of quality, advertising and promotional activities, and commitment periods ending; for Company L, the consumers switched to other companies because of fee, quality, and service; and for other companies, the consumers switched to other services because of unsatisfactory quality. Second, the analysis of the elements that determined whether a consumer will switch broadband internet service providers showed that college graduates and individuals who had switched carriers voluntarily in the past were more likely to switch to a new broadband internet service provider. Furthermore, passive consumers had a higher probability of switching. Moreover, when consumers were less satisfied with the fees and services, there was a greater chance of switching to another company.

• 동의생리병리학회지
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• 제16권3호
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• pp.537-541
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• 2002

When a Kigong master concentrates the Qi at Yintang, Laogong(P8), Qihai(CV6) meridian points during Kigong state, the change of magnetic field around acupoints Yintang, Laogong points has been measured using DROS-SQUID apparatus. After smoothing process of the continuously measured magnetic signal around acupoints for a few minutes, we could observe that a series of peaks, magnitude of 1～2 pT and period of 5 sec, appeared and find that these peaks were clearly changed as if switch on and off according to Qi concentration state. Before Qi radiation, a series of the peaks measured on Yintang or Laogong point of a Kigong master shows one of either SW-ON state or SW-OFF state as initial state. During Qi radiation, its state becomes inverse of initial state. After Qi radiation, it returns to the initial state for some cases (called P type ; push button switch type) or it remains inversion state for other cases (called T type; toggle switch type). From the data of peaks measured at different position from the Qi concentration acupoint, we found that the Qi radiation on an acupoint makes the switching effect even not at the acupoint that Qi is concentrated but at the other acupoints that Qi is not concentrated.

• 한국정밀공학회지
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• 제21권2호
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• pp.203-209
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• 2004

Compliant bi-stable mechanism allows two stable states within its operation range staying at one of the local minimum states of the potential energy. Energy storage characteristics of the bi-stable mechanism offer two distinct and repeatable stable states, which require no power input to maintain it at each stable state. This paper suggests an equivalent model of the chevron-type bi-stable microactuator using the equivalent spring stiffness in the rectilinear and the rotational directions. From this model the range of spring stiffness where the bi-stable mechanism can be operated is analyzed and compared with the results of the FEA (Finite Element Analysis) using ANSYS for the buckling analysis, both of which show a good agreement. Based on the analysis, a newly designed chevron-type bi-stable MEMS actuator using hinges is suggested for the latch-up operation. It is found that the experimental response characteristics of around 36V for the bi-stable actuation for the 60$mu extrm{m}$ stroke correspond very well to the results of the equivalent model analysis after the change in cross-sectional area by the fabrication process is taken into account. Together with the resonance frequency experiment where 1760Hz is measured, it is shown that the chevron-type bi-stable MEMS actuator using hinges is applicable to the optical switch as an actuator.

• Elastomers and Composites
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• 제54권4호
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• pp.351-358
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• 2019

To evaluate the aging of a rubber pad in power window switch which is the part of a vehicle, the accelerated thermal aging test of rubber pad material is performed. Finite element analysis was performed using the nonlinear material constants of the rubber pad to calculate the operating force, and the Arrhenius relationship was derived from the aging temperature and time. The aging test was performed at 150, 180, 210, or 240 ℃ for 1 to 60 days. When the operating force of the rubber pad is changed by 10% from the initial value, the service life is expected to be 113 years, which is much longer than the life of the vehicle. This indicates that the aging life of the rubber pad is sufficiently safe and the operating force of the rubber pad during the life of the vehicle (20 years) was decreased by approximately 8.4%. By examining the correlation between the shear elastic modulus and operating force calculated from finite element analysis under each aging test condition, the changes in the operating force of the rubber pad and the shear elastic modulus showed good linear relationship. The aging life could be predicted by the change in shear elastic modulus and a process for predicting the aging life of automotive power window switch rubber pad parts is described herein.