• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.720-725
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• 2000

A new ultrasonic pulse-echo technique was developed and described for vibration measurement of the suspension assembly in hard disk drives. The method is based upon the difference in magnitude of two consecutive reflection waves from a moving object(suspension), while the traditional ultrasonic vibrometer uses the phase shift of the reference wave and the reflection wave. A cone-shape delay line is designed to access the small structure. A simple mathematical model is presented and analyzed with experimental results to show the feasibility of the method. The advantages of this ultrasonic vibration measurement method are relatively high resolution, low cost, and ease of implementation comparing with the Laser Doppler vibrometer.

• 마이크로전자및패키징학회지
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• 제26권1호
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• pp.17-21
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• 2019

본 논문에서는 공작기계 등에서 필요로 하는 진직도 측정시스템을 가시광의 레이저와 CMOS 이미지센서를 사용하여 저가로 구현하였다. CMOS 이미지센서를 이용하여 광이미지를 검출하고 영상처리를 통해 진직도 변화를 계산하였다. 레이저와 이미지센서의 거리를 3m로 하여 실험한 진직도 측정에서 오차가 0.9%로 우수함을 확인하였으며, 제작된 진직도 시스템은 3D 프린터 등 다른 응용분야에서도 사용 할 수 있을 것으로 생각된다.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.45-50
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• 2021

The adjustment of lens magnification can make the degree of precision in pattern measurement be improved, but several problems such as high cost, smaller field of view and stage error accumulation are followed. In this paper, a method for precisely measuring patterns is proposed based on gradient transition vector, in order to solve these problems. The performance of our method is evaluated using pattern images with several directions. Also, it is compared with previous methods based on edge and gray-level moment. It is judged that the proposed method outperforms consistent pattern width results, and so could be applied to automation processes for measurement and inspection of precise and complexed patterns in IT, BT industry products.

• 한국건설관리학회논문집
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• 제12권4호
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• pp.79-87
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• 2011

원가관리는 가장 기본적인 건설관리 업무기능 중 하나로서, 전통적인 관리기법이 오랫동안 활용되어 왔다. 그럼에도 불구하고, 각 건설조직 또는 각 프로젝트 특성에 따라 원가관리의 실무적인 세부기법들은 다소 다르게 적용되며, 이러한 세부기법의 선택적용은 발주방식, 경영전략, 기술전략, 그리고 현장여건 등을 포함하는 포괄적인 프로젝트 환경에 의하여 영향을 받게 된다. 우리 건설기업은 지속적이며 급격한 환경변화에 적응하며 성장하여 왔다. 이러한 맥락에서, 본 연구에서는 기업차원의 원가관리 방법을 조사함으로써 현황파악과 함께 변화추세를 분석하였다. 원가관리는 '재무관점 원가' 뿐 아니라 '기술관점 원가'에서도 매우 중요한 의미를 갖고 있으며, 본 조사는 기술적 관점의 원가로서 사업관리 기술 변화를 파악하는 데 중점을 두었다. 연구방법으로는, 우선 원가관리의 실무기능을 분류 정의하였으며, 이를 바탕으로 설문을 작성하여 각 기업의 관리방법을 조사하였고, 마지막으로 설문응답을 분석을 통하여 시사점을 도출하였다. 총 45개 종합건설기업의 응답결과를 기업규모, 매출특성 등을 기준으로 분류하여 분석하였다.

• 센서학회지
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• 제29권2호
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• pp.128-132
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• 2020

Total organic carbon (TOC) analysis equipment, which was previously used to prevent eutrophication in advance, is heavy, bulky, and expensive; therefore, so it is difficult to be carried and has been used as an experimental unit. In this study, a through-carbon analysis chip that integrates pretreatment through photocatalytic oxidation and carbon dioxide measurement using a pH indicator was investigated. Both the total carbon - inorganic carbon method and the nonpurgeable organic carbon (NPOC) measurement method require an acidification part for injecting an acid solution for inorganic carbon measurement and removal, an oxidation part for total carbon or NPOC oxidation and a measurement part for Carbon dioxide (CO₂) measurement. Among them, the measurement of oxidation and CO₂ requires physical technology. The proposed TOC analysis chip decomposed into CO₂ as a result of the oxidizing of organic carbon using a photocatalyst, and the pH indicator that was changed by the generated CO₂ was optically measured. Although the area of the sample of the oxidation part and the pH indicator of the measurement part were distinguished in an enclosed space, CO₂ was quantified by producing an oxidation part and a measurement part that shared the same air in one chip. The proposed TOC analysis chip is less expensive and smaller, cost and size are disadvantages of existing organic carbon analysis equipment, because it does not require a separate carrier gas to transport the CO₂ gas in the oxidation part to the measurement part.

• Journal of Power Electronics
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• 제16권1호
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• pp.362-373
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• 2016

The on-line measurement of high-power IGBT collector current is important for the hierarchical control and short-circuit and overcurrent protection of its driver and the sensorless control of the converter. The conventional on-line measurement methods for IGBT collector current are not suitable for engineering measurement due to their large-size, high-cost, low-efficiency sensors, current transformers or dividers, etc. Based on the gate driver, this paper has proposed a current measuring circuit for IGBT collector current. The circuit is used to conduct non-intervention on-line measurement of IGBT collector current by detecting the voltage drop of the IGBT power emitter and the auxiliary emitter terminals. A theoretical analysis verifies the feasibility of this circuit. The circuit adopts an operational amplifier for impedance isolation to prevent the measuring circuit from affecting the dynamic performance of the IGBT. Due to using the scheme for integration first and amplification afterwards, the difficult problem of achieving high accuracy in the transient-state and on-state measurement of the voltage between the terminals of IGBT power emitter and the auxiliary emitter (u_Ee) has been solved. This is impossible for a conventional detector. On this basis, the adoption of a two-stage operational amplifier can better meet the requirements of high bandwidth measurement under the conditions of a small signal with a large gain. Finally, various experiments have been carried out under the conditions of several typical loads (resistance-inductance load, resistance load and inductance load), different IGBT junction temperatures, soft short-circuits and hard short-circuits for the on-line measurement of IGBT collector current. This is aided by the capacitor voltage which is the integration result of the voltage uEe. The results show that the proposed method of measuring IGBT collector current is feasible and effective.

• 정보학연구
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• 제12권2호
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• pp.13-29
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• 2009

ERP in the past, primarily centering on large enterprises and the introduction of competition in the global e-business, but along with the proliferation of small and medium-sized enterprises are now in earnest, or to take advantage of the introduction of the ERP plan. However, the introduction of the ERP cost and the effort required to develop, because many never previously introduced ERP expect that the introduction of cost and performance comparisons with the measurement is necessary. Until now, however, the introduction of a framework of analysis followed the introduction of ERP primarily to measure performance of a major improvement. This research, in addition to improving the performance of these tasks have been overlooked until now for the system's user satisfaction BSC (Balanced Scorecard) models and techniques using AHP-specific understanding of the Company (Group executives, middle managers groups, and user groups) Importance of priorities you want to analyze. In summary, the key findings of this study follows. First, ERP user satisfaction measurement for the balanced scorecard indicators in terms of the redevelopment. Second, the information system user satisfaction to the user layer (Layer 3), grouped by the measure. Thirdly, the user satisfaction of the important topics for attention as quantified by measuring the hierarchy. This model is for satisfaction levels as quantitative of future users of the new system, information systems and the introduction of a new model of development based on the evaluation data will be able to take advantage of.

• 대한공간정보학회지
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• 제14권3호
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• pp.31-37
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• 2006

기존의 터널 측량 방법은 관측시간이 많이 소요되고, 이로 인한 공사비 증가 및 공사기간 지연 등의 문제점을 가지고 있기 때문에 터널측량에서의 오차요인과 시간 및 경비절감 문제 등을 해결할 수 있는 측량시스템을 개발하여 효율성 증대를 위한 측량방법을 제안하였다. 이러한 문제점들을 해결하기 위하여 측량 장비와 Note book 컴퓨터를 연결하여 현장에서 실시간으로 터널측량과 동시에 위치 및 오차들을 결정할 수 있는 시스템을 개발하였다. 터널측량시스템을 개발함으로서 터널 측량시 오차발생과 터널 굴착시의 미굴 및 여굴의 가능성을 최소화하여 시공품질의 향상과 원가 절감 및 공기 단축 등의 효과를 가져 올 수 있도록 하였다.

• 전기학회논문지
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• 제56권11호
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• pp.1879-1884
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• 2007

In the electric power industry, it is important that the supply of energy must be guaranteed. Many power utilities control and supervise the transmission line to avoid power failures. In case of underground tunnel, some troubles are reported in cable joint. To stabilize the power, it is needed to monitor the cable joint. Many researches of cable joint monitoring have been going on by partial discharge measurement and temperature measurement using optical cable. These methods need much cost to install and maintain, so it is only used in critical transmission line. In this research, we use wireless sensor technology, because of its low cost and easy installation. We develop the temperature monitoring system for cable joint. Temperature sensor is installed on the surface of cable joint and sends data to server through router node using wireless network. Generally Ad hoc routing is searched in wireless network. However, in this research, we design the static linear routing mechanism, which is suitable for electric power line monitoring and analyze the life time of the sensor node by measuring the amount of the battery consumption.

• 한국정보통신학회논문지
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• 제2권1호
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• pp.141-146
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• 1998

Recently, the computer vision such as part measurement, and product inspection is very popular to achieve the factory automation since the labor cost is dramatically increasing. In this paper, the diameter and the length of rope are measured by CCD camera which is orthogonally mounted on the ceiling. Two parameters which are the diameter and the length of rope are used to measure the weight of rope. If the weight of rope is reached to predetermined weight, the information is transmitted to PLC(programmable logic control) to cut the rope on the wheel. The cutting machine cuts the rope according to the information obtained from the CCD camera. To measure the diameter and length of rope on real time, the searching space for image segmentation is restricted the predetermined area according to the camera calibration position. Finally, to estimate the weight of rope, the knowledge base system which depends on the diameter, the length of rope, and weight relation between these information are constructed according to diameters of rope. This method contributes to achieve the factory automation, and reduce the production cost since the operators are unnecessary to measure the weight of rope by try-and-error method.