• Journal of international Conference on Electrical Machines and Systems
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• 제3권4호
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• pp.428-432
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• 2014

Rotating machines are an integral part of large electrical power machinery in most of the industries. Any degradation or outages in the rotating electric machinery can result in significant losses in productivity. It is critical to monitor the equipment for any degradation's so that it can serve as an early warning for adequate maintenance activities and repair. Prior research and field studies have indicated that the rotating machines have a particular type of signal structure during the initial start-up transient. A machine performance can be studied based on the effect of degradation in signal parameters. In this paper a data-acquisition system and the FFT algorithm has been design and model using the MATLAB and Simulink. The implementation had been carried out on the TMS320 DSP Processor and various testing and verification of the machine performance had been carried out. The results show good agreement with expected results for both simulated and real-time data. The real-time data from AC water pumps which have rotating motors built-in were collected and analysed. The FFT algorithm provides frequency response and based on this frequency response performance of the machine had been measured.The FFT algorithm provides only approximation about the machine performances.

• 한국공간구조학회논문집
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• 제19권4호
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• pp.103-110
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• 2019

The cable-based retractable membrane roof makes it impossible to maintain its shape and stiffness during driving process, unlike the hard-type retractable roof. Consequently, monitoring using a relatively simple wireless video transmission device is required. However, since video data has a bigger transmission rating than other monitoring data in terms of the structure velocity or acceleration, there is a need to develop transmission device that is easy to install and entails low maintenance cost. This paper studies on a real-time video transmission system for monitoring the cable-based retractable membrane roof while driving. A video transfer software, using the mobile network, is designed and the embedded system is constructed. Ultimately, the data transmission server is tested. Connecting a trolley to the system allows testing of the validity and efficiency of the developed system through the video data transmitted in the driving process. Result of the test shows that the developed system enables multi-device data transfer with monitoring via the mobile network.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.192-200
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• 2010

Korea is part of a region of low or moderate seismic zone in which few earthquakes have been monitored, so it is difficult to approve design ground motions and seismic responses on structures from response spectrum. In this study, a series of dynamic centrifuge model tests for demonstrating seismic amplification characteristics in soil-foundation-structure system were performed using electro-hydraulic shaking table mounted on the KOCED 5.0 m radius beam centrifuge at KAIST in Korea. The soil model were prepared by raining dry sand and $V_S$ profiles were determined by performing bender element tests before shaking. The foundation types used in this study are shallow embedded foundation and deep basement fixed on the bottom. Total 7 building structures were used and the response of building structures were compared with response spectrum from the acceleration records on surface.

• 정보처리학회논문지A
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• 제11A권3호
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• pp.109-114
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• 2004

최근 무선 랜의 확산과 블루투스 등의 개인 무선 통신의 발전으로 네트워크 환경은 점차 유무선 구분 없이 쉽게 네트워크에 접속할 수 있도록 변화되고 있다. 또한, 가정 내의 노트북, PDA 등의 네트워크 군기의 증가는 초고속 인터넷 라인을 공유하여 이용하고 기기 간에 네트워크를 구성해 작업하는 환경을 필요로 한다. 본 논문에서는 유무선 네트워크에 구분 없이 손쉽게 연결할 수 있고 인터넷에 접속할 수 있는 다중 네트워크 인터페이스를 지원하는 유무선 통합 액세스 포인트를 개발하여 기능을 시험하고 성능을 검증하였다. 각기 다른 네트워크간의 통합을 이루고 성능을 보장하기 위한 시스템 하드웨어 설계, 개발 단계부터 프로토콜 소프트웨어 개발까지 실질적 개발내용을 기술하고, 다양한 형태의 기기를 통한 네트워크 접속 시험을 통해 연동 및 성능에 대한 결과를 보였다.

• 센서학회지
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• 제17권3호
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• pp.183-187
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• 2008

A sub-ppm level MEMS gas sensor that can be used for the detection of formaldehyde (HCHO) is presented. It is realized by using a zinc oxide (ZnO) thin-film material with a Ni-seed layer as a sensing material and by bulk micromachining technology. To enhance sensitivity of the MEMS gas sensor with Ni-seed layer was embedded with ZnO sensing material and sensing electrodes. As experimental results, the changed sensor resistance ratio for HCHO gas was 9.65 % for 10 ppb, 18.06 % for 100 ppb, and 35.7 % for 1 ppm, respectively. In addition, the minimum detection level of the fabricated MEMS gas sensor was 10 ppb for the HCHO gas. And the measured output voltage was about 0.94 V for 10 ppb HCHO gas concentration. The noise level of the fabricated MEMS gas sensor was about 50 mV. The response and recovery times were 3 and 5 min, respectively. The consumption power of the Pt micro-heater under sensor testing was 184 mW and its operating temperature was $400^{\circ}C$.

• 대한의용생체공학회:의공학회지
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• 제26권2호
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• pp.117-122
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• 2005

The elastic modulus and the apparent density of the trabecular bone were evaluated from spherical indentation tests and Computed Tomography (CT) and their relationship was quantified. The femurs were prepared for trabecular bone analysis. Embedded with respect to their anatomical orientation, the transverse planes of the trabecular bone specimens were scanned at 1㎜ intervals using a CT scanner. The metaphyseal regions of femurs were sectioned with a diamond-blade saw, producing 8㎜ cubes. Using a specially made spherical indentation tester, the cubes were mechanically tested in the anterior-posterior (AP), medial-lateral (ML), and inferior-superior (IS) directions. After determination of modulus from the mechanical testing, the apparent densities of the specimens were measured. The results showed that the IS modulus was significantly greater than both the AP and ML moduli with the AP modulus greater than the ML modulus. This demonstrated that orthogonality was a structural characteristic of the trabecular bone. The power relationship between the modulus and the apparent density was also found to be statistically significant.

• Advances in Computational Design
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• 제3권4호
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• pp.385-404
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• 2018

The study investigated an area of sustainable structural design that is often overlooked in practical engineering applications. Specifically, a novel method to simultaneously optimise the cost and embodied carbon performance of steel building structures was explored in this paper. To achieve this, a parametric design model was developed to analyse code compliant structural configurations based on project specific constraints and rigorous testing of various steel beam sections, floor construction typologies (precast or composite) and column layouts that could not be performed manually by engineering practitioners. Detailed objective functions were embedded in the model to compute the cost and life cycle carbon emissions of the different material types used in the structure. Results from a comparative numerical analysis of a real case study illustrated that the proposed optimisation approach could guide structural engineers towards areas of the solution space with realistic design configurations, enabling them to effectively evaluate trade-offs between cost and carbon performance. This significant contribution implied that the optimisation model could reduce the time required for the design and analysis of multiple structural configurations especially during the early stages of a project. Overall, the paper suggested that the deployment of automated design procedures can enhance the quality as well as the efficiency of the optimisation analysis.

• 한국음향학회지
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• 제20권7호
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• pp.3-12
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• 2001

본 연구에서는 소리에 대한 주관적 평가 인자 중 하나인 러프니스 계산 모델을 구현하였다. 구현된 러프니스 모델은 기존 모델의 고찰을 통해 계산 모델을 구체화하였으며, 주파수 영역으로부터 상호 상관 인자를 구하는 방법 등을 이용하여 계산 효율 및 정확도를 향상시켰다. 또한 기존의 주관적인 러프니스 평가치와의 비교를 통해 구현된 모델의 유용성을 확인하였다. 한편 기존 모델 및 구현된 러프니스 계산 모델을 통해 얻을 수 있는 러프니스 스펙트럼이 주파수 영역에서의 슬롭 가진(slope excitation)의 영향으로 인해 실제 변조되는 주파수 대역을 탐색하기 어려운 점을 발견하고, 구현된 모델의 상관 인자 계산 부분을 실제 변조가 발생하는 임계 대역에서만 러프니스 스펙트럼 값이 존재하도록 수정하여, 러프니스 기여성분의 탐색이 보다 용이해진 방법을 제안하였다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권2호
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• pp.201-206
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• 2010

발전소와 임베디드 시스템, 지능형 빌딩과 같은 현대의 대부분의 시스템은 PLC 라는 특수목적 컴퓨터를 이용하여 자동제어된다. PLC 프로그래밍 언어 중에서 가장 많이 사용하는 것은 LD 프로그램이다. LD 프로그램의 검증은 시뮬레이션과 테스팅등을 통해 이루어지는데 이러한 방법은 프로그램 검증에 한계가 있다. 본 논문에는 LD 프로그램의 검증시 모델 체킹을 사용할 수 있도록 주어진 LD 프로그램을 모델 체커의 입력으로 자동으로 변환하는 방법을 기술한다. LD 프로그램과 SMV 모델의 의미구조를 정의 하고 이를 바탕으로 의미가 보존되는 변환 함수를 정형적으로 나타낸다.

• 정보처리학회논문지D
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• 제14D권6호
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• pp.649-656
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• 2007

오늘날 차량네트워크(CAN)는 전기적 강인, 저가격과 접근지연 때문에 분산 임베디드 시스템에서 널리 사용되는 버스형 필드이다. 그러나 버스토폴로지에서 발생하는 의존적인 제한 때문에 차량네트워크가 어플리케이션상에서 안전적으로 사용되는지는 논쟁되어왔다. 그래서 차량네트워크(CAN) 디자인 단계 동안 데이터 버스의 부하와 최대 지연, 경쟁 우선순위와 같은 네트워크의 성능을 분석하는 것이 중요하게 되었다. 이 논문은 차량네트워크의 성능을 평가하기 위해 사용된 시뮬레이션 알고리즘과 고장 기법 기술을 적용을 소개한다. 이는 차량네트워크의 어떤 산만한 구현의 줄임과 시스템의 신뢰성을 향상 시켜 줄 것이다.