• 한국소음진동공학회논문집
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• 제18권7호
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• pp.725-731
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• 2008

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centre (NS, 1942) ground motion histories with different peak ground acceleration (PGA) ranging from 0.06 g to 0.50 g. For model updating, flexural stiffness values of structural members (walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions (i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of Inputs for updating (j.e. transfer function and natural frequencies) The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters (i.e. flexural stiffness values).

• 방송공학회논문지
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• 제5권2호
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• pp.281-289
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• 2000

영상을 획득하는 과정에 있어서 영상 획득 장치 또는 피사체의 흔들림은 영상에 손상을 가져온다. 이러한 손상을 움직임 열화(motion blur)라고 부르며, 영상의 선명도를 떨어뜨리는 주된 원인이 된다. 최근 연구에서 밝힌 극점자취 방법을 통해 주어진 열화영상에서 열화의 PSF(Point Spread Function) 특성을 구하는데 사용되는 중요한 파라메터를 추출 할 수 있다. 이러한 극점 자취방법으로, 노이즈에 의한 열화에 관계없이 적은 연산량으로 움직임 열화의 방향을 추출할 수 있다. 본 논문에서는 통계적 극점 자취 접근법을 새롭게 제안한다. 저주파 영역에서 움직임 열화방향의 추정오차를 줄이기 위해 ML(Maximum Likelihood)분류를 통해 오차를 유발하는 극점을 선택하여 가중치를 적용, 그 영향을 최소화한다. 선형 예측법을 사용하여, 불규칙적 자료가 극점으로 선택되는 것을 방지한다 제안된 MALM(Moving average least mean)방법은 두번째로 큰 극점의 검출을 위해 움직임의 정도를 판별하는데 사용된다. MALM방법은 자체적으로 노이즈 제거 과정을 내포하고 있으므로 노이즈가 많은 환경에서도 파라메터를 추출할 수가 있다. 실험에서 우리는 제안된 방법을 통해 얻어진 정보를 사용하여, 열화 된 이미지를 효율적으로 복구해 낼 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.330-335
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• 2000

This paper deals with sensing ability of smart sensor that has a sensing ability of distinguish materials. We have developed new signal processing method that have distinguish different materials. We made the two type of smart sensors for experiment. The first type of smart sensor is H2 type. The second type of smart sensor is HH type. The smart sensor was developed for recognition of material. And then we developed estimation method of sensing ability of smart sensors. The first method(Sensing Ability Index) is developed for H2 smart sensor. The second method($R_{SAI}$ Index) is developed for HH smart sensor. We estimated sensing ability of smart sensor with new SAI and $R_{SAI}$ method. This paper describes our primary study for a new method of estimate sensing ability of smart sensor, which is need for precision work system. This is a study of dynamic characteristics of smart sensor according to frequency and displacement changing with new SAI and $R_{SAI}$ method. Experiment and analysis are executed for proper dynamic sensing condition. First, we developed advanced smart sensors. Second, we develop new SAI and $R_{SAI}$ methods that have a sensing ability of distinguish materials. Dynamic characteristics of smart sensor are evaluated through new SAI and $R_{SAI}$ method relatively. We can use the new SAI and $R_{SAI}$ method for finding materials. Applications of this method are finding abnormal condition of object(auto-manufacturing), feeling of object(medical product), robotics, safety diagnosis of structure, etc.

• 지구물리와물리탐사
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• 제11권1호
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• pp.68-77
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• 2008

2.5차원 전자탐사 적분방정식의 확장된 Born 근사해 또는 국소 비선형 근사에 기초하여 루프-루프 전자탐사 역산 알고리듬이 개발되었다 송수신 배열은 수평 동일면(HCP) 또는 수직 동일면(VCP) 방식이고, 다중 주파수 및 다중 송수신 간격을 포함할 수 있으며 PC에서 작동된다. 안정적이고 고해상도를 유지하는 역산이 가능하도록 변수분해 행렬과 Backus-Gilbert 분산 함수 분석을 통해 감도 분포의 함수로서의 공간적으로 변화하는 최적 Lagrange 곱수 결정 알고리듬을 포함하였다. HCP와 VCP 배열 자료가 지하 전기비저항 구조에 따라 서로 다른 감도를 가짐에 따라 동시 역산에서 안정성과 해상도에 영향을 미치게 되므로, 계산값과 측정값 차의 분산에 따라 가중치를 적용하는 방식을 도입하였다. 모델링 코드의 정확성은 통상적으로 루프-루프 전자탐사에서 사용하는 주파수 및 송수신 간격 범위에서 유한차분법에 의해 계산된 결과와의 비교를 통하여 증명되었다. 개발된 역산 알고리듬은 먼저 반무한 공간내 전도체 및 저항체가 포함된 모델에 대한 계산자료에 적용되어 성능이 입증되었다. 현장자료에 적용하고 그 결과 영상을 전기비저항 탐사자료에 대한 역산 결과와 비교하여, 의미있는 지하구조의 영상을 얻을 수 있음을 확인하였다.

• Smart Structures and Systems
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• 제20권3호
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• pp.273-283
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• 2017

This paper presents and compares three feedback control strategies for active control of noise inside a 3-D vibro-acoustic cavity. These are a) control strategy based on direct output feedback (DOFB) b) control strategy based on linear quadratic regulator (LQR) to reduce structural vibrations and c) LQR control strategy with a weighting scheme based on structural-acoustic coupling coefficients. The first two strategies are indirect control strategies in which noise reduction is achieved through active vibration control (AVC), termed as AVC-DOFB and AVC-LQR respectively. The third direct strategy is based on active structural-acoustic control (ASAC). This strategy is an LQR based optimal control strategy in which the coupling between the various structural and the acoustic modes is used to design the controller. The strategy is termed as ASAC-LQR. A numerical model of a 3-D rectangular box cavity with a flexible plate (glued with piezoelectric patches) and with other five surfaces treated rigid is developed using finite element (FE) method. A single pair of collocated piezoelectric patches is used for sensing the vibrations and applying control forces on the structure. A comparison of frequency response function (FRF) of structural nodal acceleration, acoustic nodal pressure, and piezoelectric actuation voltage is carried out. It is found that the AVC-DOFB control strategy gives equal importance to all the modes. The AVC-LQR control strategy tries to consume the control effort to damp all the structural modes. It is seen that the ASAC-LQR control strategy utilizes the control effort more intelligently by adding higher damping to those structural modes that matter more for reducing the interior noise.

• 한국자동차공학회논문집
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• 제18권1호
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• pp.105-111
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• 2010

In the field of 'Human Vibration', it has been interested subjects to make equal sensation curves related to translational and rotational direction of whole-body, hand-transmitted and head-transmitted vibration, etc. When we consider the vibration of a vehicle, the main factor is vertical whole-body vibration. Until now, most of equal sensation curves used to derive frequency weighting function had been made using Western people. However, because of the inherent differences (for example, characteristic and shape of body parts, muscular and cellular tissue) between the Western people and the Oriental people, equal sensation curves based on Oriental people might be required. Also, the weight differences between the samples which consist of average-weighted and over-weighted group might cause the difference of equal sensation curves. So, in this study, 20 male Korean people were used to find equal sensation curves subject to vertical whole-body vibration on seated posture. Among 20 males, an over weighted group consisted of 10 male persons and an average weighted group was the others. Integrating and analyzing the data of two groups, some of non-parametric tests such as 'The Wilcoxon Signed Rank Test' and 'The Mann Whitney U test' were used.

• 한국소음진동공학회논문집
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• 제27권2호
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• pp.155-161
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• 2017

When a military vehicle is driven on a cross-country road, the occupants are exposed to vibration at a body resonance. In case that the exposure continues for too long period, the attention ability of the occupant could be affected by the vibration exposure. In the study, it was experimentally tried to find if there is a correlation between degradation of attention and vibration exposure. Two kinds of test among various psychological attention tests were employed, which were selected with considering a situation of carrying out military mission on vehicle. At the result, the searching test for controlled attention showed significant degradation in the accuracy and performance time in case of exposure at the vibration. And the attention degradation appeared to be greater when the vibration exposure increases. The dual task test for divided attention showed the difference between vibration and non-vibration condition, but showed it is insignificant for the attention to degrade by increasing exposure time.

• 농촌계획
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• 제7권1호
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• pp.37-48
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• 2001

The purpose of this study is to suggest the landscape potential index for visualizing landscape information in the conservation of hilly landscape in urban fringe. For the visual and quantitative approach to topological landscape assessment, numerical entity data of DEM(digital elevation model) were processed with CAD-based utilities that we developed and were mainly focused on analysis of visibility and visual sensitivity. Some results, with reference in assessing greenbelt area of Eodeung Mt. in Gwangju, proved to be considerable in the landscape assessment of suburban hilly landscapes. 1) Since the viewpoints and viewpoint fields were critical to landscape structure, randomized 194 points(spatially 500m interval) were applied to assessing the generalized visual sensitivity, we called. Because there were similar patterns of distribution comparing to those by 56 points and 18 Points given appropriately, it could be more efficient by a few viewpoints which located widely. 2) Regressional function was derived to represent the relationships between probabilities of visibility frequency and the topological factors(topological dominance, landform complexity and relational aspect) of target field. 3) Visibility scores of each viewpoint were be calculated by summing the visual sensitivity indices within a scene. The scores to the upper part including ridge line have been more representative to overall distributions of visual sensitivities. Also, with sum of deviations of sensitivity indices from each single point's specific index to the weighting values of view points could be estimated rotationally. 4) The deviational distributions of visual sensitivity classes in the topological unit of target field were proved to represent the visual vulnerability of the landform. 5) Landscape potential indices combined with the visual sensitivity and the DGN(degree of green naturality) were proposed as visualized landscape information distributed by topological unit.

• 한국정보통신학회논문지
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• 제16권5호
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• pp.982-988
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• 2012

본 연구에서는 이중게이트(Double Gate; DG) MOSFET에서 문턱전압과 스켈링 이론의 관계를 관찰하였다. 기존 MOSFET의 경우 채널크기에 스켈링 이론을 적용하여 전류 및 스위칭주파수를 해석하였다. 이에 본 연구에서는 이중게이트 MOSFET에서 문턱전압의 경우 스켈링 이론의 적용가능성을 관찰하기 위하여 문턱전압의 변화를 스켈링 인자에 따라 관찰하고 분석하였다. 이를 위하여 이미 검증된 포아송방정식의 해석학적 전위분포를 이용하였으며 이때 가우스함수의 전하분포를 사용하였다. 분석결과 문턱전압이 스켈링 인자에 따라 크게 변화하였으며 변화정도는 도핑농도의 스켈링에 따라 변화한다는 것을 관찰하였다. 특히 이중게이트의 특성상 채널두께 및 채널길이에 스켈링 이론을 적용할 때 가중치를 이용한 변형된 스켈링 이론을 적용함으로써 이중게이트 MOSFET에 가장 타당한 스켈링 이론에 대하여 설명할 것이다.

• 동의신경정신과학회지
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• 제30권1호
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• pp.1-11
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• 2019

Objectives: Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by a persistent pattern of inattention and/or hyperactivity impulsivity that interferes with function or development in children. In traditional Korean medicine (TKM) and traditional Chinese medicine (TCM), ADHD is classified by several patterns based on symptoms and signs. However, currently, there is no objective diagnostic tool for ADHD in traditional medicine. The objective of this study was to develop the Pattern Identification Questionnaire for ADHD (parents-survey style) to be used in Korean medicine, through a literature review and consultation with groups of experts. Methods: The types of pattern identifications of ADHD mentioned in 13 pieces of Korean and Chinese literatures and their symptoms and signs were analyzed. The advisory committee (15 Neuropsychiatrist and 11 Pediatrist in Korean Medicine) assessed the appropriateness of the literature selection and the types of pattern identification selection and their symptoms and signs, and weighed the significance of the symptoms and signs. The Pattern Identification Questionnaire for ADHD was developed using the calculated weights by evaluated significance. The translation of symptoms and signs to the Korean language was achieved through consultation with expert translators. Results: 1. Four pattern identification types and their symptoms and signs were selected according to frequency of appearance in the Korean and Chinese literatures, and were reviewed by the advisory committee: Kidney yin deficiency and liver yang ascendant hyperactivity (腎虛肝亢), Dual deficiencies in the heart and spleen (心脾兩虛), Phlegm-fire harassing the heart (痰火擾心), and Spleen weakness and liver energy preponderance (脾虛肝旺). 2. The weights of all the symptoms and signs in the four patterns were calculated using the means and standard deviations of the symptoms and signs' importance that were obtained from specialists' significance weighting. 3. The Pattern Identification Questionnaire for ADHD (parents-survey style) in Korean medicine composed of 38 questions was suggested. Conclusions: Using a review of the literature and expert advice, Pattern Identification Questionnaire for ADHD (parents-survey style) in Korean medicine was developed. Further clinical study is required to develop a final version of the questionnaire through the evaluation of reliability and validity.