• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.58-60
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• 2000

This paper presents the modeling methods to analyze the static and dynamic performances for practical power system loads using field measurement data. Also, it is included that the several modeling techniques using EMTDC program and field measuring method for real static dynamic loads. As a result of this study, through the comparisons between simulation results and measurement data, typical parameters of static and dynamic loads according to the variation of system voltage and frequency are given.

• 아동학회지
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• 제30권5호
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• pp.225-243
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• 2009

This study analyzed the effects of dynamic assessment in terms of scaffolding group types and young children's measurement ability levels. Participants were five-year-old children in Busan divided into 2 experimental groups and control groups. The Assessment Tools for Young Children's Measurement Ability (Ko & Hwang, 2008) consisted of 4 sub tests for ‘length', 'width', and 'weight' concepts. Data were analyzed by t-test and ANOVA. Results showed significant differences between experimental and control groups in post-test scores, but no significant differences between individual and peer collaboration groups in amount of scaffolding. Significant improvements showed in all of the measurement ability level groups : individual higher, individual lower, peer collaboration higher and peer collaboration lower level scaffolding groups.

• 정보처리학회논문지C
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• 제12C권4호
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• pp.519-524
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• 2005

동하중 측정 데이터에 추가되는 여러 가지 종류의 오차로 인하여, 신뢰할 수 있는 하중을 구하기 위해 측정 오차를 감소시키는 적절한 방법이 필요하다. 과도한 진동으로 인해 발생하는 측정 오류는 쉽게 제거하기 어렵다. 이러한 오류를 최소화하기 위하여 측정 장치 혹은 측정 대상의 수직 운동과 상호 관계가 전혀 없는 광 센서 시스템을 이용한다. 여러 가지 시료들의 흐름률을 광 센서를 이용하여 측정함으로써 로드셀을 이용한 부정확한 측정 부분을 보완한다. 동하중 측정시 발생하는 잡음 감소를 확인하기 위하여 모형 트레일러 시스템을 사용하며, 제안된 방법이 효과적임을 확인한다.

• Wind and Structures
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• 제20권6호
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• pp.719-737
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• 2015

Full scale measurement on the structural dynamic characteristics and Vortex-induced Vibrations (VIV) of a long-span suspension bridge with a central span of 1650 m were conducted. Different Finite Element (FE) modeling principles for the separated twin-box girder were compared and evaluated with the field vibration test results, and the double-spine model was determined to be the best simulation model, but certain modification still needs to be made which will affect the basic modeling parameters and the dynamic response prediction values of corresponding wind tunnel tests. Based on the FE modal analysis results, small-scaled and large-scaled sectional model tests were both carried out to investigate the VIV responses, and probable Reynolds Number effects or scale effect on VIV responses were presented. Based on the observed VIV modes in the field measurement, the VIV results obtained from sectional model tests were converted into those of the three-dimensional (3D) full-scale bridge and subsequently compared with field measurement results. It is indicated that the large-scaled sectional model test can probably provide a reasonable and effective prediction on VIV response.

• Smart Structures and Systems
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• 제19권6호
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• pp.679-694
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• 2017

The complexity, enlargement and irregularity of structures and multi-directional dynamic loads acting on the structures can lead to unexpected structural behavior, such as torsion. Continuous torsion of the structure causes unexpected changes in the structure's stress distribution, reduces the performance of the structural members, and shortens the structure's lifespan. Therefore, a method of monitoring the torsional behavior is required to ensure structural safety. Structural torsion typically occurs accompanied by displacement, but no model has yet been developed to measure this type of structural response. This research proposes a model for measuring dynamic torsional response of structure accompanied by displacement and for identifying the torsional modal parameter using vision-based displacement measurement equipment, a motion capture system (MCS). In the present model, dynamic torsional responses including pure rotation and translation displacements are measured and used to calculate the torsional angle and displacements. To apply the proposed model, vibration tests for a shear-type structure were performed. The torsional responses were obtained from measured dynamic displacements. The torsional angle and displacements obtained by the proposed model using MCS were compared with the torsional response measured using laser displacement sensors (LDSs), which have been widely used for displacement measurement. In addition, torsional modal parameters were obtained using the dynamic torsional angle and displacements obtained from the tests.

• Smart Structures and Systems
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• 제16권3호
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• pp.521-535
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• 2015

Vibration-based monitoring is one approach used to perform structural condition assessment. By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar's measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.

• 한국전기전자재료학회논문지
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• 제22권10호
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• pp.864-869
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• 2009

The measurement of contact wire uplift in electric railways is one of the most important test parameters to accepting the maximum permitted speed of new electric vehicles and pantographs. The contact wire uplift can be measured over short periods when the pantograph passes monitoring stations. In this paper, a high-speed image measurement system and its image processing method are being developed to evaluate dynamic uplift of overhead contact wires caused by pantograph contact forces of Korea Tilting Train eXpress (TTX) and Korea Train eXpress (KTX). The image measurement system was implemented utilizing a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera and gigabit ethernet LAN. Unlike previous systems, the uplift measurement system using high speed camera is installed on the side of the rail, making maintenance convenient. On-field verification of the uplift measurement system for overhead contact wire using high speed camera was conducted by measuring uplift of the TTX followed by operation speeds at the Honam conventional line and high-speed railway line. The proposed high-speed image measurement system to evaluate dynamic uplift of overhead contact wires shows promising on-field applications for high speed trains such as KTX and TTX.

• 스마트미디어저널
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• 제4권2호
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• pp.34-45
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• 2015

윈도우는 국내에서 가장 많이 사용되는 운영체제이기 때문에 윈도우용 소프트웨어를 대상으로 불법 복제가 많이 이루어지고 있고 불법 복제로 인해 소프트웨어 저작권이 침해될 수 있다. 이를 보호하기 위해서 저작권 보호 방법 중 하나인 소프트웨어 버스마크를 사용한다. 소프트웨어 버스마크는 소프트웨어로부터 특정 정보들을 추출하여 소프트웨어간 도용 여부를 판별할 수 있는 기술이며 대상 소프트웨어로 부터 특정 정보를 추출하는 방법에 따라 정적 버스마크와 동적 버스마크로 구별된다. 정적 버스마크와 동적 버스마크는 서로 장단점을 가지고 있지만 본 논문에서는 API 기반 동적 버스마크를 이용한 유사도 측정 기법을 제안하고, 동적 버스마크의 추출 과정을 설명한다. 또한 실험을 통해 제안하는 동적 버스마크의 유사도 측정 기법이 신뢰성과 강인성을 만족하는 것을 확인할 수 있었으며 기존 동적 버스마크의 유사도 측정 기법보다 제안하는 동적 버스마크의 성능이 향상 된 것을 확인할 수 있었다.

• 산업경영시스템학회지
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• 제41권2호
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• pp.65-73
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• 2018

The dynamic capabilities of sensing market signals, creating new opportunities and reconfiguring resources and capabilities to new opportunities in a rapidly changing economic environment determines the competitiveness of the enterprise to create added value and survival. This study conceptualized a two-stage performance measurement framework based on the casual model of resource (input)-process-performance (output). We have developed a 'Process capability index' that reflect the dynamic capabilities factors as a key intermediary product linking resource inputs and performance outputs in enterprise performance measurement. The process capability index consists of four elements : manpower (level of human resource), operation productivity, structure and risk management. The DEA (Data Envelopment Analysis) model was applied to the developed performance indicators to analyze the branch office performance of a telecom company. Process capability efficiency (stage 1) uses resource inputs to reach a certain level of process capabilities. In performance result efficiency (stage 2), the process capabilities are used to generate sales revenues and subscribers. The two-stage DEA model derives intermediate output values that optimize the individual stages simultaneously. Some branch offices in the telecom company have focused on process capability efficiency or some other branch offices focused on performance result efficiency. Positioning map using two-stage efficiency decomposition and benchmarking can help identify the sources of inefficiencies and visualize strategic directions for performance optimization. Applications of two-stage DEA in conjunction with the case study that are meaningfully used in performance measurement areas have been scarce. In particular, this paper has the contribution to present a new performance measurement model considering the organization theory, the dynamic capabilities.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.161-169
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• 2006

Load representation has a significant impact on power system analysis and control results. In this paper, composite load models are developed based on on-line measurement data from a practical power system. Three types of static-dynamic load models are derived: general ZIP-induction motor model, Exponential-induction motor model and Z-induction motor model. For the dynamic induction motor model, two different third-order induction motor models are studied. The performances in modeling real and reactive power behaviors by composite load models are compared with other dynamic load models in terms of relative mismatch error. In addition, numerical consideration of ill-conditioned parameters is addressed based on trajectory sensitivity. Numerical studies indicate that the developed composite load models can accurately capture the dynamic behaviors of loads during disturbance.