• 한국자동차공학회논문집
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• 제16권1호
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• pp.52-63
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• 2008

The side collision reconstruction algorithm is developed using three dimensional car crash analysis. Medium size passenger car is modeled for finite element analysis. Total 24 side collision configurations, four different speed and six different angle, are set up for making side collision database. Deformation index and degree index are built up for each collision case. Deformation index is a kind of deformation estimate averaging displacement of side door of crashed car from finite element analysis result. Angle index is constructed measuring deformed angle of crashing car. There are two kinds of angle index, one is measured at driver's side and the other is measured at passenger's side. Also a collision analysis information in side of cars is used for giving a basis for scientific and practical reason in a reconstruction of the car accident. The analysis program, LS-DYNA3D is utilized for finite element analysis program for a collision analysis. Those database are used for side collision reconstruction. Side collision reconstruction algorithm is developed, and applied to find the collision conditions before the accident occurs. Three example collision cases are tried to check the effectiveness of the algorithm. Deformation index and angle index is extracted for the case from the analysis result. Deformation index is compared to the established database, and estimated collision speed and angle are introduced by interpolation function. Angle index is used to select a specific collision condition from the several available conditions. The collision condition found by reconstruction algorithm shows good match with original condition within 10% error for speed and angle. As a result, the calculation from the reconstruction of the situation is reproducing the situation well. The performance in this study can be used in many ways for practical field using deformation index and degree index. Other different collision situations may be set up for extending the scope of this study in the future.

• Computers and Concrete
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• 제20권5호
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• pp.555-562
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• 2017

The accuracy and integrity of stress data acquired by bridge heath monitoring system is of significant importance for bridge safety assessment. However, the missing and abnormal data are inevitably existed in a realistic monitoring system. This paper presents a data reconstruction approach for bridge heath monitoring based on the wavelet multi-resolution analysis and support vector machine (SVM). The proposed method has been applied for data imputation based on the recorded data by the structural health monitoring (SHM) system instrumented on a prestressed concrete cable-stayed bridge. The effectiveness and accuracy of the proposed wavelet-based SVM prediction method is examined by comparing with the traditional autoregression moving average (ARMA) method and SVM prediction method without wavelet multi-resolution analysis in accordance with the prediction errors. The data reconstruction analysis based on 5-day and 1-day continuous stress history data with obvious preternatural signals is performed to examine the effect of sample size on the accuracy of data reconstruction. The results indicate that the proposed data reconstruction approach based on wavelet multi-resolution analysis and SVM is an effective tool for missing data imputation or preternatural signal replacement, which can serve as a solid foundation for the purpose of accurately evaluating the safety of bridge structures.

• 한국지능시스템학회논문지
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• 제20권1호
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• pp.101-108
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• 2010

본 논문에서는 퍼지 k-NN과 reconstruction error에 기반을 둔 feature selection을 이용한 lazy 분류기 설계를 제안하였다. Reconstruction error는 locally linear reconstruction의 평가 지수이다. 새로운 입력이 주어지면, 퍼지 k-NN은 local 분류기가 유효한 로컬 영역을 정의하고, 로컬 영역 안에 포함된 데이터 패턴에 하중 값을 할당한다. 로컬 영역과 하중 값을 정의한 우에, feature space의 차원을 감소시키기 위하여 feature selection이 수행된다. Reconstruction error 관점에서 우수한 성능을 가진 여러 개의 feature들이 선택 되어 지면, 다항식의 일종인 분류기가 하중 최소자승법에 의해 결정된다. 실험 결과는 기존의 분류기인 standard neural networks, support vector machine, linear discriminant analysis, and C4.5 trees와 비교 결과를 보인다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1313-1315
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• 2003

This paper is dedicated to studying the quantitative analysis method with remote-sensing data in shallow geological structure reconstruction by the example of TM data in western China. A new method of computing attitude of geological contacts from remote-sensing data is developed and assessed. We generate several geological profiles with remotely derived measurements to constrain the shallow geological structure reconstruction in three dimensions.

• Journal of Mechanical Science and Technology
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• 제17권4호
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• pp.571-580
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• 2003

Tomography has been investigated to observe bubble behaviors in two-phase flows. A bubbly flow and an annular flow have been reconstructed by tomography methods such as an algebraic reconstruction technique (ART) and a multiplicative algebraic reconstruction technique (MART) . Computer synthesized phantom fields have been used to calculate asymmetric density distributions for limited cases of 3, 5, and 7 projection angles. As a result of comparison of two tomography methods, the MART method has shown a significant improvement in the reconstruction accuracy for analysis of the two-phase flows.

• 한국자동차공학회논문집
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• 제12권2호
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• pp.205-214
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• 2004

This paper presents design concepts, specifications and performances of a newly developed Black Box, the reconstruction analysis tool with the records, and results of validation tests. The Black Box can detect crash accidents automatically, and record the vehicle's motion and driver's maneuvers during a pre-defined time period before and after the accident. The items of the Black Box included the acceleration, yaw-rate, vehicle speed, engine RPM, braking application, steering and several digital inputs for recording driver's maneuvers. To detect the accident-related-crash, it is important to understand characteristics of the crash signal, which are much different from those of normal driving. Therefore, analytical considerations should be taken in designing pre-filtering circuits and selecting appropriate parameters for identifying crash accidents. And, it is necessary to select proper combination of motion sensors and design proper pre-filtering circuits in order to describe the vehicle's motion. The analysis algorithms were developed and implemented which can perform accurate detection of crash accidents, simulating pre-crash trajectories, and calculating parameters for reconstruction analysis of crash accidents. The developed Black Box was installed on passenger cars and several types of validation tests were conducted. Through the tests, the accuracy of the recorded data and usefulness of the analysis tool for reconstruction have been validated.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.477-480
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• 2003

기존의 재건축 안전진단의 비용분석은 정량적이지 못한 평가기준과 방법 등 많은 문제점을 가지고 있어 좀더 효율적으로 안전진단 업무를 수행하고, 비용분석 결과의 신뢰성을 향상시키기 위해서는 체계적인 비용분석 절차 및 기준이 필요하다. 따라서 본 연구에서는 각 비용항목들을 정량적으로 도출${\cdot}$산정하고, 효율적으로 비용분석을 수행하기 위한 절차 및 기준을 제시하고자 한다. 재건축 안전진단의 비용분석은 먼저, 내용연수, 실질이자율 등의 기본사항을 결정하고, 구조체 보수${\cdot}$보강비용, 건축 마감 및 설비 성능회복비용, 철거비, 이주비, 유지관리비용 등의 개${\cdot}$보수 비용 및 재건축 비용을 산정하여 이들 비용의 LCC 년가를 비교하여 분석${\cdot}$평가한다.

• 대한후두음성언어의학회지
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• 제18권2호
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• pp.134-137
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• 2007

Background and Objectives: The goals of laryngeal reconstruction have been prevention of aspiration, production of a functional voice, and maintenance of an adequate airway for decannulation. It is generally believed that the reconstruction of the glottic region after vertical partial laryngectomy (VPL) can improve laryngeal function. The objective of this study is to evaluate of voice function after VPL with mucosal flap and fat graft reconstruction. Materials and Methods: From 1994 to 2006, 13 patients, who had been treated with VPL with mucosal flap and fat graft reconstruction. The voice characteristics, acoustic, aerodynamic parameter were measured in 13 patients after vertical partial laryngectomy with mucosal flap and fat graft reconstruction. Acoustic analysis was carried out using Computerized Speech Lab (CSL) and aerodynamic analysis were carried out using Aerophon II,3 months and 12 months after surgery. Results: The GRBAS scale, jitter, shimmer, NHR were improved as time goes on after surgery. But, maximum phonation time was shortened after surgery and there is no significant differences between before and after surgery in mean flow rate. Conclusion: The voice function of the mucosal flap and fat graft reconstruction after VPL were satisfactory. This can be an excellent reconstruction method after vertical partial laryngectomy.

• Korean Journal of Radiology
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• 제20권4호
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• pp.558-568
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• 2019

Objective: To evaluate whether computed tomography (CT) reconstruction algorithms affect the CT texture features of the liver parenchyma. Materials and Methods: This retrospective study comprised 58 patients (normal liver, n = 34; chronic liver disease [CLD], n = 24) who underwent liver CT scans using a single CT scanner. All CT images were reconstructed using filtered back projection (FBP), hybrid iterative reconstruction (IR) (iDOSE⁴), and model-based IR (IMR). On arterial phase (AP) and portal venous phase (PVP) CT imaging, quantitative texture analysis of the liver parenchyma using a single-slice region of interest was performed at the level of the hepatic hilum using a filtration-histogram statistic-based method with different filter values. Texture features were compared among the three reconstruction methods and between normal livers and those from CLD patients. Additionally, we evaluated the inter- and intra-observer reliability of the CT texture analysis by calculating intraclass correlation coefficients (ICCs). Results: IR techniques affect various CT texture features of the liver parenchyma. In particular, model-based IR frequently showed significant differences compared to FBP or hybrid IR on both AP and PVP CT imaging. Significant variation in entropy was observed between the three reconstruction algorithms on PVP imaging (p < 0.05). Comparison between normal livers and those from CLD patients revealed that AP images depend more strongly on the reconstruction method used than PVP images. For both inter- and intra-observer reliability, ICCs were acceptable (> 0.75) for CT imaging without filtration. Conclusion: CT texture features of the liver parenchyma evaluated using the filtration-histogram method were significantly affected by the CT reconstruction algorithm used.

• 한국주거학회논문집
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• 제10권1호
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• pp.145-154
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• 1999

In this study, various factors affect on the reconstruction of the deteriorated apartment housing complex in the Taegu-City were analyzed. The conclusions obtained in this research were summarized as follows; 1) In case of 4 to 5 storied apartment buildings, those were main objects for reconstruction. The number of the buildings and households consisting apartment complex and the total building area and the ground area were appeared as major factors. Those factors were highly correlated with the consensus of reconstruction. 2) As a maximun area of reconstruction was limited, higher existing consensus capacity and its ratio affect negatively on reconstruction of deteriorated apartments. 3) The main motivation for reconstruction is disadvantages among the members of reconstruction association were main obstacles to reconstruct the deteriorated apartment buildings. Therefore, a resoanble alternatives for reconstruction plans and administrative managements were needed.