• 제목/요약/키워드: Parametric Study

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3D Digital Design Optimization Process Considering Constructability of Freeform Structure (비정형 구조물의 시공성을 고려한 3차원 디지털 설계 최적화 프로세스)

  • Ryu, Han-Guk
    • Korean Journal of Construction Engineering and Management
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    • v.14 no.5
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    • pp.35-43
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    • 2013
  • Nowadays the widely used media in architecture include visualizations, animations and three-dimensional models. 3D digital methods using active CAM(Computer Aided Manufacturing) and CNC(Computerized Numerical Control) imaging have been developed for accurate shape and 3D measurements in freeform buildings. In contrast to a conventional building using auto CAD system and others, the proposed digital optimization method is based on a combination of 3D numerical data and parametric 3D model for design and construction. The objective of this paper is therefore to present digital optimization process for constructability of freeform building. The method can be useful in the effective implementation of an error-proofing process of freeform building during design and construction phase. 3D digital coordinate data can be used effectively to identify correct size of structural and finish members and installation location of each members in construction field. In addition, architects, engineers and contractors can evaluate design, materials, constructability and identify error-proofing opportunities. Other project participants can also include representatives from all levels of management, departments as well as workers and key subcontractors' personnel, if necessary. The 3D digital optimization process is therefore appropriate to serious variations in freeform shape. For future study, the developed digital optimization method is necessary to be carried out to verify the robustness and accuracy for constructability in construction field.

Indeterminate Strut-Tie Model and Load Distribution Ratio of Continuous RC Deep Beams (I) Proposal of Model & Load Distribution Ratio (연속지지 RC 깊은 보의 부정정 스트럿-타이 모델 및 하중분배율 (I) 모델 및 하중분배율의 제안)

  • Kim, Byung-Hun;Chae, Hyun-Soo;Yun, Young-Mook
    • Journal of the Korea Concrete Institute
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    • v.23 no.1
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    • pp.3-12
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    • 2011
  • The structural behavior of continuous reinforced concrete deep beams is mainly controlled by the mechanical relationships associated with the shear span-to-effective depth ratio, flexural reinforcement ratio, load and support conditions, and material properties. In this study, a simple indeterminate strut-tie model which reflects characteristics of the complicated structural behavior of the continuous deep beams is presented. In addition, the reaction and load distribution ratios defined as the fraction of load carried by an exterior support of continuous deep beam and the fraction of load transferred by a vertical truss mechanism, respectively, are proposed to help structural designers for the analysis and design of continuous reinforced concrete deep beams by using the strut-tie model approaches of current design codes. In the determination of the load distribution ratio, a concept of balanced shear reinforcement ratio requiring a simultaneous failure of inclined concrete strut and vertical steel tie is introduced to ensure a ductile shear failure of reinforced concrete deep beams, and the primary design variables including the shear span-to-effective depth ratio, flexural reinforcement ratio, and concrete compressive strength are implemented after thorough parametric numerical analyses. In the companion paper, the validity of the presented model and load distribution ratio was examined by applying them in the evaluation of the ultimate strength of multiple continuous reinforced concrete deep beams, which were tested to failure.

Robust determination of control parameters in K chart with respect to data structures (데이터 구조에 강건한 K 관리도의 관리 모수 결정)

  • Park, Ingkeun;Lee, Sungim
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.6
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    • pp.1353-1366
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    • 2015
  • These days Shewhart control chart for evaluating stability of the process is widely used in various field. But it must follow strict assumption of distribution. In real-life problems, this assumption is often violated when many quality characteristics follow non-normal distribution. Moreover, it is more serious in multivariate quality characteristics. To overcome this problem, many researchers have studied the non-parametric control charts. Recently, SVDD (Support Vector Data Description) control chart based on RBF (Radial Basis Function) Kernel, which is called K-chart, determines description of data region on in-control process and is used in various field. But it is important to select kernel parameter or etc. in order to apply the K-chart and they must be predetermined. For this, many researchers use grid search for optimizing parameters. But it has some problems such as selecting search range, calculating cost and time, etc. In this paper, we research the efficiency of selecting parameter regions as data structure vary via simulation study and propose a new method for determining parameters so that it can be easily used and discuss a robust choice of parameters for various data structures. In addition, we apply it on the real example and evaluate its performance.

Estimating Method of Starting Point Bias in Bidding Game (서베이를 이용한 입찰게임에서 출발점 편의의 추정)

  • 박용치
    • Survey Research
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    • v.4 no.2
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    • pp.63-86
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    • 2003
  • The objective of this study was to investigate the existence of starting point bias in the bidding game contingent valuation elicitation technique when determining willingness to pay (WTP) for improving the qualify of running water in Seoul and its vicinity. Of all existing contingent techniques, the bidding game most closely mimics the normal price taking behavior in local markets. Three different starting points (low, medium and high) were used to determine WTP and the existence of starting point bias in the meanwhile respectively. The respondents were randomly assigned to the three different starting point groups in order to ensure homogeneity, so that any variation seen in WTP could be attributed to the starting point effects. And a pretested interviewer-administered questionnaire used to elicit WTP. Non-parametric test and the logit model were used to analyze the data for evidence of starting point bias. In this instance, the high starting point group had a high WTP, and low starting point group had a low WTP. This means there exist starting point bias in estimating WTP by bidding game in this instance. This finding might signal that people may actually be making up their minds on the maximum amount they are willing to pay for running water service as a bidding iterating is going on and is influenced by the starting point used in the bidding game. The problem of slaking point bias can be avoided if the respondent is asked directly for the maximum WTP without payment cards or a bidding game. But such a question is perceived as being very difficult to answer and this leads to problems of non-response and being unrealistic.

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A Parametric Study of Pulsed Gamma-ray Detectors Based on Si Epi-Wafer (실리콘 에피-웨이퍼 기반의 펄스감마선 검출센서 최적화 연구)

  • Lee, Nam-Ho;Hwang, Young-Gwan;Jeong, Sang-Hun;Kim, Jong-Yeol;Cho, Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.7
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    • pp.1777-1783
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    • 2014
  • In this paper, we designed and fabricated a high-speed semiconductor sensor for use in power control devices and analyzed the characteristics with pulsed radiation tests. At first, radiation sensitive circular Si PIN diodes with various diameters(0.1 mm ~5.0 mm) were designed and fabricated using Si epitaxial wafer, which has a $42{\mu}m$ thick intrinsic layer. The reverse leakage current of the diode with a radius of 2 mm at a reverse bias of 30 V was about 20.4 nA. To investigate the characteristic responses of the developed diodes, the pulsed gamma-radiation tests were performed with the intensity of 4.88E8 rad(Si)/sec. From the test results showing that the output currents and the rising speeds have a linear relationship with the area of the sensors, we decided that the optimal condition took place at a 2 mm diameter. Next, for the selected 2 mm diodes, dose rate tests with a range of 2.47E8 rad(Si)/sec to 6.21E8 rad(Si)/sec were performed. From the results, which showed linear characteristics with the radiation intensity, a large amount of photocurrent over 60mA, and a high speed response under 350ns without saturation, we can conclude that the our developed PIN diode can be a good candidate for the sensor of power control devices.

Evaluation of Impact Resistance for Concrete Median Barrier Depending on Vehicle Curb Weight, Concrete Cover Depth and Level of Deterioration (트럭 공차중량, 중앙분리대 피복두께 및 열화수준에 따른 중앙분리대 충돌해석모델의 민감도 분석)

  • Lee, Jaeha;Lee, Ilkeun;Jeong, Yoseok;Kim, Kyeongjin;Kim, WooSeok
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.4
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    • pp.297-306
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    • 2017
  • The concrete median barrier used currently in South Korea was developed the impact level of SB5-B(270kJ). However, the impact level of SB6(420kJ) should be considered in many placed with the increased accident of heavy vehicles. In order to increase the impact resistance of newly developed concrete median barrier, the computer simulation was conducted before real field test. For the accurate behavior of concrete, the parameter, such as impact vehicle, concrete cover depth and deterioration, was important. In this paper, a parametric study was conducted depending on vehicle curb weight, concrete cover depth and level of deterioration. The impact resistance of concrete median barrier was severely changed depending on vehicle curb weight and concrete cover depth. Furthermore, the impact resistance of concrete median barrier was also decreased due to deterioration of concrete, therefore the repair and rehabilitation should be conducted for damaged concrete depending on deterioration level. Therefore, vehicle curb weight, cover depth of concrete structures and deterioration level of concrete should be carefully considered for conducting analysis of concrete structure to vehicle collision.

A Study on the Optimum Navigation Route Safety Assessment System using Real Time Weather Forecasting (실시간 기상 정보를 이용한 최적 항로 안전 평가 시스템의 연구)

  • Choi, Kyong-Soon;Park, Myung-Kyu;Lee, Jin-Ho;Park, Gun-Il
    • Proceedings of KOSOMES biannual meeting
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    • 2007.05a
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    • pp.203-210
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    • 2007
  • This paper treats optimal route safety assessment system at seaway based on weather forecasting data through INMARSAT. Since early times, captain have been sailing to select the optimum route considering the weather, ship loading status condition and operational scheduling empirically. However, it is rare to find digitalized onboard route support system whereas weather facsimile or wave and swell chart are utilized for the officer, based on captain's experience. In this paper, optimal route safety assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA(estimated time of arrival) and fuel consumption that shipping company. and captain are requiring to evaluate for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method Basically, the weather forecast is assumed to be prepared previously in order to operate this system.

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Survey on Effect and Satisfaction of Korean Medicine Distillate Nasal Spray of Patient with Chronic Rhinitis (만성 비염 환자의 한방코분무제에 대한 효과 및 만족도 조사)

  • Kim, Ji-Eun;Hong, Chul-Hee
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.25 no.3
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    • pp.56-64
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    • 2012
  • Objectives : This study was performed in order to investigate an immediate improvement effect of nasal obstruction after having patient with chronic rhinitis use nasal spray in nasal cavity after distilling Korean medicine, satisfaction for its fragrance and irritation and its effect continuance time. Methods : A questionnaire was performed for an immediate therapeutic effect of nasal spray 1, 2 and 3 weeks later after using spray by targeting 13 patients who used Korean medicine distillate spray for over 3 weeks among the patients who visited Sangji University Korean Medicine Hospital and whose symptoms were determined as chronic rhinitis and for whom Korean medicine distillate spray was prescribed. 3 weeks later after using spray, a questionnaire was performed for fragrance, irritation and continuance effect of Korean medicine. Immediate therapeutic effect being felt right after spraying was also surveyed and symptom scores was expressed from 10 to 0 and on the assumption that nasal obstruction symptom just before spraying was 10 points, symptom score after spraying was surveyed. In case of evaluation of satisfaction, satisfaction for fragrance and irritation of nasal spray was evaluated by scale based on full score of 5 point from 'very satisfied=5', 'satisfied=4', 'average=3', 'unsatisfactory=2' and 'very unsatisfactory=1', respectively. Effect continuance time after spraying was surveyed by dividing it into within 5 minutes, within 5-10 minutes, within 10-30 minutes and over 30 minutes. All the data was statistically analyzed by Friedman Test that is non-parametric test of Paired t-test and descriptive statistics. Results : Total surveyed patients were 13 persons including 6 males and 7 females and total average age was represented to be $27.1{\pm}17.7$ years old. Score of immediate nasal obstruction improvement effect at 1st week was $6.3{\pm}2.4$ points, at 2nd week $5.7{\pm}2.5$ points and at 3rd week $5.5{\pm}2.5$ points and when comparing 1st week, 2nd week and 3rd week statistically, p value was 0.047<0.05 and from this, it could be seen that the longer spray was used, the more was improvement effect represented with slight significance. In case of fragrance and irritation, both of its score was represented to be high as average $4.0{\pm}1.08 $points and average $4.4{\pm}0.8$ points, respectively. Effect continuance time below 10 minutes was represented in 8 persons who accounted for 61.5%. Conclusions: Immediate improvement effect of nasal obstruction being felt by the patients by using Korean medicine nasal spray could be confirmed and by having the patients use such spray for 3 weeks continuously, it could be realized that such effect was sustained and satisfaction for fragrance or irritation of Korean medicine nasal spray was significant. However, rather short sustained time was considered to be unsatisfactory and this shortcomings is required to be improved in the future.

The Study on the Economic Effects of Advanced Water Treatment by using CVM (CVM을 이용한 고도정수처리의 경제적 효과 분석)

  • Jang, Seok Won;Kim, Shang Moon
    • Journal of Korea Water Resources Association
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    • v.48 no.9
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    • pp.711-717
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    • 2015
  • This paper attempts to measure the economic benefits of advanced water treatment in five cities (Goyang, Paju, Gumi, Gimcheon, Chilgok), which are supplied water from Goyang and Gumi filtration plant. We used the dichotomous choice contingent valuation method to estimate WTP. Parametric interval-data model are used to obtaining the mean WTP estimates. The results show that the mean of additional WTP for advanced water treatment services were estimated to be KRW 231.3 and KRW 231.2 per $m^3$ using model with covariates and without covariates, respectively. Given the water supplies of Goyang and Gumi filtration plants ($59.675m^3/y$ and $93.734m^3/y$), the economic benefits of those advanced water treatments can be expected to be KRW 13.8 billion and KRE 21.68 billion. And the calculated B/C ratios are 3.7 and 2.1 when a lifespan of facility is 10 years. Advanced water treatment should be introduced in terms of the economic benefits and costs. Thus, this results can be useful in water policy decision-making.

An Application of Artificial Intelligence System for Accuracy Improvement in Classification of Remotely Sensed Images (원격탐사 영상의 분류정확도 향상을 위한 인공지능형 시스템의 적용)

  • 양인태;한성만;박재국
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.20 no.1
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    • pp.21-31
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    • 2002
  • This study applied each Neural Networks theory and Fuzzy Set theory to improve accuracy in remotely sensed images. Remotely sensed data have been used to map land cover. The accuracy is dependent on a range of factors related to the data set and methods used. Thus, the accuracy of maps derived from conventional supervised image classification techniques is a function of factors related to the training, allocation, and testing stages of the classification. Conventional image classification techniques assume that all the pixels within the image are pure. That is, that they represent an area of homogeneous cover of a single land-cover class. But, this assumption is often untenable with pixels of mixed land-cover composition abundant in an image. Mixed pixels are a major problem in land-cover mapping applications. For each pixel, the strengths of class membership derived in the classification may be related to its land-cover composition. Fuzzy classification techniques are the concept of a pixel having a degree of membership to all classes is fundamental to fuzzy-sets-based techniques. A major problem with the fuzzy-sets and probabilistic methods is that they are slow and computational demanding. For analyzing large data sets and rapid processing, alterative techniques are required. One particularly attractive approach is the use of artificial neural networks. These are non-parametric techniques which have been shown to generally be capable of classifying data as or more accurately than conventional classifiers. An artificial neural networks, once trained, may classify data extremely rapidly as the classification process may be reduced to the solution of a large number of extremely simple calculations which may be performed in parallel.