• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2414-2433
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• 2019

The aim of this paper is to design a 3D laser radar prototype based on laser triangulation. The mathematical model of distance sensitivity is deduced; a pixel-distance conversion formula is discussed and used to complete 3D scanning. The center position extraction algorithm of the spot is proposed, and the error of the linear laser, camera distortion and installation are corrected by using the proposed weighted average algorithm. Finally, the three-dimensional analytic computational algorithm is given to transform the measured distance into point cloud data. The experimental results show that this 3D laser radar can accomplish the 3D object scanning and the environment 3D reconstruction task. In addition, the experiment result proves that the product of the camera focal length and the baseline length is the key factor to influence measurement accuracy.

• 한국산업보건학회지
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• 제33권1호
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• pp.3-5
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• 2023

Objective: This study introduces exposure concentrations of time-weighted average standard (TWA) evaluation and short-time exposure standard (STEL) evaluation for trichloroethylene in the cleaning process. Methods: Trichloroethylene measurement was conducted according to the KOSHA Guide (A-24-2019) method. It was carried out twice. Results: As a result of the first measurement, TWA concentration exceeded 4 times the exposure standard and STEL concentration exceeded 16 times, but the inaccuracy and breakthrough of the collection time could not be considered, so the second measurement was conducted. The second measurement result was lower than the first measurement result, but exceeded the exposure standards (TWA, STEL). Conclusions: We were able to confirm that the exposure level of workers in the cleaning process using trichloroethylene exceeded the exposure standard. And it is also considered necessary to grasp the approximate concentration using a detector tube in the preliminary survey.

• Journal of applied mathematics & informatics
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• 제42권3호
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• pp.709-723
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• 2024

We study the distributions of waiting times in variations of the geometric distribution of order k. Variation imposes length on the runs of successes and failures. We study two types of waiting time random variables. First, we consider the waiting time for a run of k consecutive successes the first time no sequence of consecutive k failures occurs prior, denoted by T^(k). Next, we consider the waiting time for a run of k consecutive failures the first time no sequence of k consecutive successes occurred prior, denoted by J^(k). In addition, we study the distribution of the weighted average. The exact formulae of the probability mass function, mean, and variance of distributions are also obtained.

• Geomechanics and Engineering
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• 제36권1호
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• pp.83-97
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• 2024

It is important to make reasonable prediction about the long-term deformation of high rockfill geostructures. However, the deformation is usually underestimated using the rockfill parameters obtained from laboratory tests due to different size effects, which make it necessary to identify parameters from in-situ monitoring data. This paper proposes a novel hybrid back-analysis method with a modified objective function defined for the time-dependent back-analysis problem. The method consists of two stages. In the first stage, an improved weighted average method is proposed to quickly narrow the search region; while in the second stage, an adaptive response surface method is proposed to iteratively search for the satisfactory solution, with a technique that can adaptively consider the translation, contraction or expansion of the exploration region. The accuracy and computational efficiency of the proposed hybrid back-analysis method is demonstrated by back-analyzing the long-term deformation of two high embankments constructed for airport runways, with the rockfills being modeled by a rheological model considering the influence of stress states on the creep behavior.

• Journal of information and communication convergence engineering
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• 제1권3호
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• pp.119-122
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• 2003

In this paper presents equations which describe an average weighted spectrum of errors and average block error probabilities for noncoherent frequency shift keying (NCFSK) used in D-branch maximal ratio combining (MRC) diversity in independent very slow nonselective Nakagami fading channels. The average is formed over the instantaneous receiver signal to noise ratio (SNR) after combining. the analysis is limited to additive Gaussian noise.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 1999년도 춘계 공동학술발표회
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• pp.120-122
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• 1999

• 지구물리와물리탐사
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• 제5권2호
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• pp.126-134
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• 2002

• Journal of the Korean Data and Information Science Society
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• 제23권6호
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• pp.1065-1074
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• 2012

한국 프로야구에서 출루 능력과 장타력이 득점 생산성에 미치는 영향을 통계적으로 분석하였다. 2절에서는 OPS (On-base percentage Plus Slugging average)에 관하여 고찰하고 그것을 변형한 새로운 타격지표들을 소개하였다. 3절에서는 2007년부터 2011년까지의 정규리그 전 경기 자료를 바탕으로 타율, 출루율, 장타율, IsoP (Isolated Power), OPS 및 2절에서 소개된 지표들이 팀의 경기당 평균득점과 갖는 상관관계를 알아보았다. 또한 OPS와 2절에서 소개된 지표들을 일반화하여 여러 가지 가중값을 갖는 타격지표들이 팀의 경기당 평균득점과 갖는 상관관계를 분석하였다. 그 결과 출루율에 57%, 장타율에 43%의 가중값을 주는 가중OPS가 득점 생산성을 가장 잘 설명하는 타격지표인 것으로 밝혀졌다.

• 한국컴퓨터정보학회논문지
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• 제10권6호
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• pp.65-74
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• 2005

본 논문에서는 비디오의 자동분류를 지원하기 위한 기반기술로서. 변형된 $x^{2}$-테스트와 자동 임계치 결정 알고리즘을 이용한 장면전환 검출 방법을 제안하였다. 변형된 $x^{2}$-테스트는 기존의 컬러 히스토그램과 각 채널 공간(RGB)에 NTSC표준에 따른 명암도 등급을 따로 계산하여 채널의 차이 값을 보다 세분화 할 수 있으며, 두 프레임사이의 상대적인 컬러 값 차이를 강조하는 기존의 $x^{2}$-테스트를 결합하여 보다 강건한 장면전환을 검출할 수 있다. 자동 임계치 결정 알고리즘은 연속된 프레임들로부터 변형된 $x^{2}$-테스트를 이용하여 추출된 차이 값을 이용한다. 먼저, 주어진 전체 차이 값들로부터 평균과 표준편차를 구하며, 이 평균값을 만족하는 차이 값들로부터 다시 평균과 표준편차를 계산하며, 이러한 연속적인 평균값 및 표준편차의 계산으로부터 표준편차가 가장 큰 시점에서의 평균값을 기준으로 임계치를 결정하는 방법이다. 제안된 방법은 다양한 비디오 데이터에서 실험되었으며, 실험결과 제안된 방법은 자동 임계치 결정에 효율적이며, 신뢰할만한 장면들을 검출하였다.

• 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.