• 제목/요약/키워드: Direct methods

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Direct and indirect methods for determination of mode I fracture toughness using PFC2D

  • Sarfarazi, Vahab;Haeri, Hadi;Shemirani, Alireza Bagher
    • Computers and Concrete
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    • 제20권1호
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    • pp.39-47
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    • 2017
  • In this paper, mode I fracture toughness of rock was determined by direct and indirect methods using Particle Flow Code simulation. Direct methods are compaction tension (CT) test and hollow centre cracked quadratic sample (HCCQS). Indirect methods are notched Brazilian disk (NBD) specimen, the semi-circular bend (SCB) specimen, hollow centre cracked disc (HCCD), the single edge-notched round bar in bending (SENRBB) specimen and edge notched disk (END). It was determined that which one of indirect fracture toughness values is close to direct one. For this purpose, initially calibration of PFC was undertaken with respect to data obtained from Brazilian laboratory tests to ensure the conformity of the simulated numerical models response. Furthermore, the simulated models in five introduced indirect tests were cross checked with the results from direct tests. By using numerical testing, the failure process was visually observed. Discrete element simulations demonstrated that the macro fractures in models are caused by microscopic tensile breakages on large numbers of bonded discs. Mode I fracture toughness of rock in direct test was less than other tests results. Fracture toughness resulted from semi-circular bend specimen test was close to direct test results. Therefore semi-circular bend specimen can be a proper test for determination of Mode I fracture toughness of rock in absence of direct test.

4지 신호교차로에서 효율적 자전거 교통류 처리방안 연구 (A Study on Efficient Management of Bicycle Traffic Flow at Four-Legged Intersections)

  • 목승준;김응철;허희범
    • 한국도로학회논문집
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    • 제15권3호
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    • pp.177-189
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    • 2013
  • PURPOSES: This study aims to suggest a proper left-turn treatment method for the bicycle traffic flow at four-legged intersections. METHODS: Four types of crossing methods are proposed and analyzed : (1) indirect left turn, (2) direct left turn, (3) direct left turn on a Bike Box, and (4) direct left turn on bike left turn lane. The VISSIM simulation tests were conducted based on forty-eight operation scenarios prepared by varying vehicle and bicycle traffic volumes. RESULTS : The results from the four-legged signalized intersections suggest that (1) the indirect left turn is appropriate when vehicle demand is high, (2) the direct left turn is efficient on most traffic situation but the safety is a concern, (3) the direct left turn on a Bike Box is appropriate when bicycle demand is high while vehicle demand is not, and (4) the direct left turn on a bike left turn lane is appropriate when both vehicle and bicycle demand are low. CONCLUSIONS : The direct left turn of bicycle provides more efficiency than the indirect left turn at the four-legged intersections but to apply the methods and to study more, advanced evaluation methods, related law, and insurance programs are needed.

The Impact of Methods of Presenting Cash Flow Statement on Loan Decision: Evidence from Vietnam

  • NGUYEN, Dung Duc
    • The Journal of Asian Finance, Economics and Business
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    • 제7권8호
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    • pp.87-94
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    • 2020
  • The paper aims to investigate the impact of presenting statements of cash flow using the direct method and the indirect method on loan decision by credit officers at Vietnamese banks. The data was collected from 150 credit officers of commercial banks in Vietnam based on the questionnaire about making loan decision when the cash flow statement is presented in different methods, namely, direct and indirect methods. This research uses T-tests to check whether using the direct or indirect method affects the accurate calculation of loan criteria, affects the loan decision by credit officers, and compare these two methods in the aspects of information provision. The research has pointed out that: 1) the direct method helps the calculation of indicators related to loans more accurately; 2) credit officers say that, while the direct method of presenting cash flow statement provides clearer information, the use of either the direct method or the indirect method does not affect the banks' loan decision. Since then, the author recommends that cash flow statements should be provided with information in a direct method to present the information needed for loan decision more accurately so as to improve the quality of cash flow statement.

간접보기 도구를 이용한 치과 진료 관련 작업자세에 대한 인간공학적 분석 (An Ergonomic Analysis on Working Posture Associated with Dental Treatment Using Indirect Viewing Method)

  • 손창원;최순영;박동현
    • 대한안전경영과학회지
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    • 제12권2호
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    • pp.55-64
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    • 2010
  • This study tried to focus on nontraditional job that has not been studied in terms of the subjects associated with MSDs(Musculoskeletal Disorders). Specifically, dental procedure was the job to be analyzed in this study. An alternative method as well as a traditional method for viewing teeth while performing simulated dental procedures. Four graduated students did both methods(direct view and indirect view) as the subjects in this study. The method based on indirect view used a video camera and monitor to view the teeth. The experiment was conducted five times for each subject. The major findings in this study were as follows; 1) Job speed was increased with the repetitions for both methods, 2) Difference of Neck flexion between direct and indirect methods was statistically siginificant(Neck flexion for indirect method was dramatically decreased), 3) Difference of job speed between direct and indirect methods was statistically significant(Job speed for direct method was faster than that of indirect method), 4) Difference of error rate between direct and indirect methods was statistically significant(error rate for direct method was lower than that of indirect method), 5) Even though indirect method did not provide better performance in terms of job speed and error rate yet, it seemed to need a trade-off between two methods in the future since indirect method provided better working postures than that of direct method.

Combining an Edge-Based Method and a Direct Method for Robust 3D Object Tracking

  • Lomaliza, Jean-Pierre;Park, Hanhoon
    • 한국멀티미디어학회논문지
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    • 제24권2호
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    • pp.167-177
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    • 2021
  • In the field of augmented reality, edge-based methods have been popularly used in tracking textureless 3D objects. However, edge-based methods are inherently vulnerable to cluttered backgrounds. Another way to track textureless or poorly-textured 3D objects is to directly align image intensity of 3D object between consecutive frames. Although the direct methods enable more reliable and stable tracking compared to using local features such as edges, they are more sensitive to occlusion and less accurate than the edge-based methods. Therefore, we propose a method that combines an edge-based method and a direct method to leverage the advantages from each approach. Experimental results show that the proposed method is much robust to both fast camera (or object) movements and occlusion while still working in real time at a frame rate of 18 Hz. The tracking success rate and tracking accuracy were improved by up to 84% and 1.4 pixels, respectively, compared to using the edge-based method or the direct method solely.

직접적분법과 확률론적 유한요소법을 이용한 구조물의 확률론적 동적 해석 (Developing A Stochastical Dynamic Analysis Technique for Structures Using Direct Integration Methods)

  • 이정재
    • 한국농공학회지
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    • 제36권1호
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    • pp.54-62
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    • 1994
  • The expanding technique of the Stochastic Finite Element Method(SFEM) is proposed in this paper for adapting direct integration methods in stochastical dynamic analysis of structures. Grafting the direct integration methods and the SFEM together, one can deal with nonlinear structures and nonstationary process problems without any restriction. The stochastical central diffrence and stochastic Houbolt methods are introduced to show the expanding technique, and their adaptabilities are discussed. Results computed by the proposed method (the Stochastic Finite Element Method in Dynamics: SFEMD) for two degree-of-free- dom system are compared with those obtained by Monte Carlo Simulation.

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품종 증식을 위한 매년 채종시 직파와 이식에 따른 5년생 인삼의 품종별 지하부 생육 특성 (Difference in Growth Characteristics of 5-Year-Old Ginseng Grown by Direct Seeding and Transplanting)

  • 김영창;김영배;김장욱;이정우;조익현;방경환;김동휘;김기홍
    • 한국약용작물학회지
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    • 제23권6호
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    • pp.480-488
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    • 2015
  • Background : In order to determine the effects of planting methods on root growth of ginseng varieties, two different methods, direct seed sowing and transplanting were compared in terms of their effects on different root growth characteristics. Methods and Results : Higher fresh root weight was observed in ginseng grown by direct seed sowing. Direct seed sowing of three cultivars (Sunhyang, Chungsun and K-1) resulted in higher yield, whereas no difference was observed in the yield of one cultivar (Chungsun). Gumpoong was highly tolerant to physiological stress, as it showed fewer symptoms of rusty and rough skin root diseases in both direct seed sowing and transplanting. The average main root length per total root length of ginseng grown by direct seed sowing was 33.6%, whereas that of ginseng grown by the average of those by transplanting was 22.4%. Other root growth characteristics, including root length, main root diameter, and number of side roots, improved when the direct seed sowing method was used. Conclusions : To our knowledge, this is the first study reporting the differences in root growth parameters of ginseng varieties grown by direct seed sowing or transplanting at the same planting density. Because of the advantages of direct sowing during ginseng planting, developing new varieties and improving cultivation methods are imperative.

우(疣)치료에 사용된 직접구(直接灸) 요법의 중의(中醫) 논문 고찰 (Review of the TCM Papers about Direct Moxibustion Therapy Used in the Treatment of Warts)

  • 박지현;손현의;서형식
    • 한방안이비인후피부과학회지
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    • 제29권1호
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    • pp.123-130
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    • 2016
  • Objective : The aim of this article is to report the chinese published papers on the results using the direct moxibustion to treat warts.Methods : Searching chinese published papers, we classified the results involved in the direct moxibustion treatment about warts. And analysed remedy methods, periods, cure rate, etc.Results : According to chinese published papers, the direct moxibustion itself may be effective in patients with warts. In all paper, the direct moxibustion showed more than 90% cure rate. The recurrence rate was low.Conclusion : We introduce a variety of wart treatments with the direct moxibustion which is made in China and report meaningful results. We hope to this paper contributes to various studies on cauterization of direct moxibustion.

다양한 혈압상태에서 직접혈압을 기준으로 HP 자동혈압기와 국산자동혈압기의 정확도 비교 (Accuracy Comparison of Blood Pressure among the Direct Measurement Method and Two Automatic Indirect Measurement Methods in the Patients with Various Blood Pressure)

  • 송효숙;전태국;최은정;김미정
    • 기본간호학회지
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    • 제8권3호
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    • pp.366-378
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    • 2001
  • Objective: The purpose of this study was to identify differences in measurement methods for blood pressure (Direct measurement, HP automatic indirect measurement, and SE 7000 Korean made indirect measurement), and to evaluate the clinical trial of the Korean made automatic indirect blood pressure measurement. Material & Methods: From June, 1999 to February, 2000, fifty five consecutive patients were randomized into hypertension group (n=20), normotension group (n=20), and hypotension group (n= 15). Measuring blood pressure by indirect methods (HP NIBP M 1008B and SE 7000 NIBP Korean made) was done simultaneously in the same arm with arterial line for direct blood pressure measurement (HP M1006A). The procedures were repeated ten times at intervals of 2 minutes. Statistical analysis was Performed using SPSS (version 8.0 for windows) software package. Values were expressed as means and standard deviation and means were compared using t-test. Statistical significance was considered present with a p value less than 0.05. Results: In the hypertension group and noromotension group, the disparity between HP direct measurement and indirect SE 7000 NIBP did not show any differences compared to the disparity between HP direct measurement and indirect HP NIBP. In the hypotension group, the disparity in the diastolic pressure between HP direct measurement and indirect SE 7000 NIBP was significantly different compared to the disparity between HP direct measurement and indirect HP NIBP (p<0.001), however, disparities in systolic pressure did not showed any differences. Conclusion: Direct blood pressure measurement (HP M1006A) can be replaced with indirect blood pressure measurements (HP NIBP M 1008B & SE 7000 NIBP) in normotension and hypertension patients. Korean made indirect measurement was found to be more accurate compared to HP indirect measurement in hypotension Patients, but more study is needed.

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고분자전해질 연료전지의 MEA 제조방법에 따른 성능비교 (The effect of MEA fabrication procedure on PEMFC performance)

  • 조용훈;조윤환;박인수;최백범;정대식;성영은
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 춘계학술대회
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    • pp.291-295
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    • 2005
  • The PEMFC behavior is quite complex and is influenced by several factors, including composition and structure of electrodes and membrane type. Fabrication of MFA is important factor for proton exchange membrane fuel cell. MFA of PEMFC with hot pressing and direct coating method were prepared, and performances were evaluated and compared each other. The effect of MEA preparation methods, hot pressing methods and direct coating methods, on the cell performance was analyzed by impedance spectroscopy and SEM. The performance of PEMFC wi th direct coat ing method was better than wi th hot pressing method because membrane internal resistance and membrane-:-interfacial resistance were reduced by elimination of hot pressing process in MEA fabrication. In addition the micro structure of MEA with direct coating method reveals uniform interface between membrane and catalyst layer.

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