• Journal of information and communication convergence engineering
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• 제8권3호
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• pp.343-347
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• 2010

Cyber education has been predicted that it would become the primary education system of 21st century as a way of education focusing on consumers, with the aspect that it seems to be able to satisfy the demand about re-education and lifelong education as the acceleration of fast knowledge accumulation throughout every field of society in the digital era. However, cyber education system has a lot of problems which are for that it lacks of human resources for effective interaction, and it can be disadvantageous to certain type of students with a class environment concentrated on reading and writing and with foundation on computer technology. Therefore, in this thesis, We intended to analyze factors influencing satisfaction of people studying in a situation that cyber education has been required to be a mainstream system of education in the midst of trend of changing paradigm of college education recently, and to suggest some possible solutions for cyber education at university.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권9호
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• pp.456-460
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• 2006

This paper deals with a novel autocalibration method of three-axis micromachined accelerometers applied to a new digital intelligent putter for golfers. This putter can help golfers monitor and analyze their putting posture and therefore modify their putting action to get better score and enjoy their lives through golf. The micromachined accelerometers to get information of the motion are the essential part of the putter to measure the three-axis acceleration as accurately as possible. This paper presents an efficient autocalibration algorithm to find the offset and sensitivity of accelerometers by only using the static measurement data at six different positions. The experimental results on the developed putters show the validity of the proposed algorithm for the new smart putter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1430-1432
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• 2001

In this paper, 200-class insulation system for form-wound stator coils is designed for form-wound stator coils is designed for AC traction driven with VVVF inverter. Model coils are made to embody all essential elements representing a winding insulation system and structure. Acceleration degradation for model coils is applied exposure to heat(235$^{\circ}C$). In order to investigate the condition of the coils and to determine their insulation reliability, high voltage test and the dielectric properties such as dielectric loss and capacitance are performed. Also, partial discharge measurement is investigated for internal defects.

• 한국공간구조학회논문집
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• 제16권4호
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• pp.109-116
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• 2016

Recently, with development of city traffic network planning, there are various effects with living space from vibration of railway. But, study which about effect from vertical vibration in floor slab in nearing structure is lack in nowadays. This thesis have analysed result from acceleration response per distance as well as proceed with serviceability evaluation and extracted natural frequency from measuring vibration of railway using mobile phone application which is oriented for building which have distances about 5m to 22m from railway.

• 천문학회지
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• 제42권6호
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• pp.175-184
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• 2009

A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.269-270
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• 2006

A finite difference lattice Boltzmann model which allows us to simulate gas-liquid two-phase flows with large density difference, for instance, 800 times for air and water is considered. Two-particle model is used and the density difference is introduced by changing the acceleration according to the fluid density. Numerical measurement of surface tension agrees well with theoretical predictions. Simulations of two-phase phenomenon for phase-transition is carried out, showing applicability of the model for two-phase flows. The two-dimensional cavitating flow around a board set up in the fluid way is also simulated. As a result, it was confirmed that the FDLB method with two-particle model was effective in numerical simulation of cavitating flow and the bubble periodically grew up at the low pressure area behind the board, in which the fluid condition was influenced by the cavitation number.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.143-147
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• 1998

As the accuracy of manufactured goods needed high-accuracy processing has made the efficiency of NC and measurment technology develop, the innovation of machine tools has influence the development of the semi-conductor and optical technology. We can mention that a traction role of the acceleration for the development like that depends on the development of the measurement technics - Stylus instrument method, STM, SEM, Laser interferometer method - which are used for measuring the movement accuracy of machine tools. The movement error factors in movement accuracy are expressed as yaw, roll, and pitch etc. Machining center has 21 movement error factors including of 3 axies joint errors because that has 3 axies and has been measured as the standard of the unloaded condition until now inspite of getting static, dynamic, and servo-gain errors in the case of expending the error range. Therefore, this study tries to measure position accuracy according to loading on the X-Y table of the machining center.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.766-771
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• 2008

In this paper, the vibration of high speed trains and the irregularity of railway are examined using a wavelet-based frequency response function. To investigate their characteristics, non-stationary acceleration data are acquired and processed using the wavelet transform. Also, the railway irregularity is examined by acquiring the data from the on-board laser-based measurement system. The correlation between the train vibration and the railway irregularity has been investigated. From the analysis, the wavelet-based frequency response function is a promised method for the dynamic characteristics of high speed trains.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.795-800
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• 2008

The sound transmission loss is a key index to evaluate the acoustic performance of a car-body structure at the high frequency range. From this paper, a new validation method for in-situ sound transmission loss is proposed. First, in-situ sound transmission loss is measured by using PU intensity probe on the condition of complete vehicle. Second, validation test, which is consisted of internal, external and total frequency response function test, is performed by using volume acceleration source and microphones. Then, these test results are compared to validate the accuracy of in-situ sound transmission loss. Finally, the test result of in-site method is compared with results of two reverberant room test method and SEA analytical method. The reliability of in-situ method is confirmed by these procedures.

• 자동차안전학회지
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• 제9권4호
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• pp.20-25
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• 2017

Dynamo based vehicle inspection device is end of line device for automobile industry. The device is utilized as implementing vehicle functionality inspection such as brake force, cruise control, kick-down acceleration, CAN inspection. As dynamo based inspection device is broadly adopted in automobile industry, the dynamic study is required to verify the vehicle test equipment reliability. This research recommends appropriate dynamic brake force inspection procedure and theoretical background for developed equipment. Dynamic characteristic of brake force implementation to roller is simplified. With simplified characteristics, the indirect brake force measurement strategy is developed and adopted. Comparison of each brake force result, the appropriate brake force inspection criterion is given.