• Title/Summary/Keyword: Regression Testing

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A Study of Eliminating the Vehicle Noise of Engine RPM from the Friction Noise between Tire and Road Pavement by Using a NCPX Method (NCPX 계측방법을 이용한 타이어/노면 사이에서 발생하는 마찰소음에 대한 차량자체에서 발생하는 소음 제거 연구)

  • Han, Bong-Koo;Kim, Do Wan;Mun, Sungho;Kim, Ha-Yeon
    • International Journal of Highway Engineering
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    • v.15 no.4
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    • pp.31-42
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    • 2013
  • PURPOSES : The purpose of this study is to eliminate the noise of the vehicle after measuring the friction noise obtained from the NCPX (Noble Close ProXimity) method. The pure friction noise between the tire and road pavement could be determined from filtering the compositeness of sound and the influence of the vehicle noise. METHODS: The noise magnitude could be determined by analyzing the sound pressure level (SPL) and sound power level (PWL) along with the noise frequency of a FFT (Fast Fourier Transform) analysis as well as CPB (Constant Percentage Bandwidth) analysis. RESULTS: When the test for measuring the friction noise originated somewhere between tire and road pavement is performed with NCPX method, it must be fulfilled by attaching the surface microphone near the tire. In this condition, the surface microphone can measure the friction noise occurred at between tire and pavement, the chassis noise from the engine and power transfer units, the fluctuating aerodynamic noise, and the turbulence noise directly affected to the surface microphone. By using the NCPX method, the noise occurred at the vehicle must be eliminated for measuring the friction noise between tire and pavement from the traffic noise. CONCLUSIONS: The vehicle's testing engine noise depends on the vehicle and road types. The effect of vehicle's engine noise is less than the friction noise occurred at between tire and pavement at less than 1% effect.

A Study of the Effect of Entrepreneurial Education on Entrepreneurial Motivation: Focused on Mediating Effect of Entrepreneurship (창업교육이 대학생들의 창업동기에 미치는 영향: 기업가정신의 매개효과를 중심으로)

  • Yang, Jun-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.4
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    • pp.2564-2572
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    • 2015
  • Entrepreneurial education for university students furnishes necessary knowledges and fosters competences of potential entrepreneurs and help them change their attitudes toward start-up of a new business. This study examines how entrepreneurial education affects promoting entrepreneurship and stimulating entrepreneurial motivation of university students. Testing mediating of entrepreneurship between entrepreneurial education and motivation is another aim of this study. Regression analysis was used to examine each hypothesis of the study. Following refers to summary of the findings of the study; at first, entrepreneurial education affects entrepreneurial motivation of university students positively. Secondly, entrepreneurial education influences promoting entrepreneurship of students. Thirdly, entrepreneurship has a positive effect on entrepreneurial motivation significantly. Lastly, entrepreneurship plays a mediating role between entrepreneurial education and motivation of students. Both theoretical and practical implication were provided based on the findings of the study.

An Experimental Study on Principal Factors for Non-destructive Test of Detecting Steel bars (비파괴 철근탐사의 주요 영향인자에 관한 실험적 연구)

  • Oh, Kwang Chin;Kim, Jong Ho;Rhee, Jong Woo;Lee, Yun Hyang
    • Journal of Korean Society of societal Security
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    • v.3 no.1
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    • pp.25-32
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    • 2010
  • Detecting rebars in side the concrete structures is one of the important steps in assessing condition of the structure. In order to determine the detection capability of locating rebars inside the concrete, two types of equipments, which use radar system and electromagnetic system each, were tested. Four concrete specimens which have the dimensions of $1,000mm(length){\times}300mm(width)$ with different thickness and diameter of steel bars were applied. A series of testing was achieved after drying in air for 90 days, immersed in water for 3, 24, 48 hour and 28 day. From the experimental outcome, it is shown that error is increased as the diameter of rebar enlarge in case of electromagnetic method. In case of radar method, the detection of embedded rebars in deep is good in the view of reliability. As moisture content increase from 3.6% to 5.5%, the relative permittivity of concrete test specimens show tendency to increase, too. Therefore, it is shown that moisture content is one of the major contributing factors to determine the relative permittivity. And the relative permittivity regression equation is suggested.

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A Study on the Effect of the Stemming Hole medium to the Blasting Separation Distance of Structure (공내 매질이 구조물의 발파이격거리에 미치는 영향에 관한 연구)

  • Kang, Hee-Seop;Jeong, Jung-Gyu;Bang, Myung-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.1
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    • pp.100-108
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    • 2017
  • Because of urbanization, Industrialization and expansion of transportation network, blasting works are recently increasing in construction field. The blasting work influences environmental effects to residents and the safety of facilities around the working place, so the development of blasting technology is needed to reduce the damage to residents. The blasting mechanism in the hole was studied and tested in the blasting sites by the difference of diameter between explosives and drilling hole, which is named by the decoupling effect. This effect was tested by changing the medium between explosives and hole wall in three working sites(railway, highway and industrial complex). The vibration velocity of blasting was recorded and vibration equations were produced by regression analyses. Finally, the structure separation distance was derived using these equations. The testing results show that the specific gravity of medium is larger, the separation distance is smaller and the duration time of blasting is shorter in case of large specific gravity of medium, so the vibration effect stops more fastly in the water compared with the air.

Development of a Semi-Quantitative Food Frequency Questionnaire for Assessing the Usual Dietary Intake of Korean Adolescents (우리나라 청소년의 일상식이섭취량 평가를 위한 반정량적 식품섭취빈도조사지의 개발)

  • Lee, Ji-Eun;Kim, Jung-Hyun;Jung, In-Kyung
    • Journal of the Korean Home Economics Association
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    • v.48 no.2
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    • pp.121-134
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    • 2010
  • This study was performed to develop the semi-quantitative food frequency questionnaire (SQFFQ) for assessing the usual dietary intake of Korean adolescents. For that, we used 24 hour recall data from the 2005 NHANES(the Third Korean National Health and Nutrition Examination Survey). The cumulative percent contribution and cumulative multiple regression coefficients of 17 nutrients(energy, protein, fat, carbohydrate, fiber, calcium, phosphorus, iron, sodium, potassium, vitamin A, retinol, ${\beta}$-carotene, thiamin, riboflavin, niacin, vitamin C) of each food were computed. Among 687 food items, 265 food items were selected and grouped depending on similarities in ingredients, nutrient profiles, and/or culinary usage and re-added food items which were excluded for seasonal effect. Finally, total 19 food groups, 87 food items, were included in SQFFQ. Food intake frequency was quantified using nine categories. The portion size was classified depending on the average size of each selected food item. Each portion size was then categorized as one of three amounts: small (0.5 times), medium (1 times), and large (1.5 times). The SQFFQ covered 91.9% of the intake of 17 nutrients in 2005 NHANES and 86.6% in 2001 NHANES. Therefore, by testing the validity of developed SQFFQ using nutrient intakes, this list was valid to evaluate the usual daily intake in Korean adolescents.

Examination of Consumer Purchase Intention for Foreign Infant Foods in China (중국에서 외국산 유아식품의 구매의도에 관한 연구)

  • Wu, Shi-Yuan;Yoon, Ki-Chang
    • Journal of Distribution Science
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    • v.15 no.3
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    • pp.49-60
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    • 2017
  • Purpose - The aims of this study are follows. We investigated to find out how country image and brand image affect the consumer perceived value, consumer attitude, and purchase intention of foreign infant foods in China. Especially, we focused on investigate for the moderating role of consumer knowledge between national image, brand image and consumer perceived value of foreign infant foods in China. Research design, data, and methodology - This study analyzed the effect of national image and brand image on purchase intention through consumer perceived value and consumer attitude. This study collected data for empirical analysis of Chinese consumers who have been purchase experience infant foods in China. 256 copies of questionnaire data were used for substantial analysis. Before testing the hypothesis, factor analysis was conducted to test the construct validity of measurement items. Hypotheses about effects between variables were verified using structural equation modeling analysis and hierarchical regression analysis. Results - First, the country image had a positive effect on consumer perceived value of foreign infant foods. Second, the brand image had a positive effect on consumer perceived value of foreign infant foods. Third, the consumer perceived value had a positive effect on consumer attitude. Fourth, the consumer attitude had a positive effect on purchase intention. Fifth, the consumer knowledge was moderating roles between brand image and consumer perceived value of foreign infant foods. However, the consumer knowledge did not effect of moderating between country image and perceived value of consumers. Conclusions - First, the impact of country image and brand image on consumer perceived value of foreign infant foods in China can be seen as a universal psychology of consumers who trust pure foreign products such as high quality, technology, etc. Second, consumer perceived value of foreign infant foods has a positive effect on consumer attitude, and this attitude is leading to purchase intention. Third, the consumer knowledge between brand image and perceived value acts as a moderating variable. It means that the consumer's knowledge can shape the perception of the brand image more strongly.

Effect of the Festival Post Image on the Satisfaction and Loyalty of Tourists (축제 사후이미지가 관광객 만족 및 충성도에 미치는 영향)

  • Kim, Si-Joong
    • Journal of the Economic Geographical Society of Korea
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    • v.15 no.1
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    • pp.63-76
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    • 2012
  • This study has the purpose of examining the effect of the festival post image on the satisfaction and loyalty of tourists in terms of revisit and recommendation for Baekjae Cultural Festival. The questionnaires for the survey were distributed among 287 visitors of Baekjae Cultural Festival. For the empirical analyses, frequency analysis, reliability analysis, factor analysis, and multiple regression analysis were used based on the conducted survey. The results are as follows: According to the analyses, five factors were drawn such as regionality, convenience, amusement, cultural characteristic of Baekjae, and management. According to the hypothesis testing, convenience, regionality, and amusement affected tourists' satisfaction for the festival, while convenience and amusement influenced revisit intention of the tourists. On the other hand, significance, convenience, and cultural characteristics of Baekjae affected recommendation intention for the festival. In conclusion, amusement & novelty and cultural characteristic of Baekjae were the factors that festival post image affected the satisfaction and loyalty of tourists in terms of revisit and recommendation for Baekjae Cultural Festival.

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The Analysis on Management Consulting Effect of a Bank on Client firms: Empirical Case Study Focused on Ante-Post Bank Consulting Effect Comparison (은행 경영컨설팅의 효과에 관한 실증연구 -A은행 사례를 이용한 컨설팅 전후 효과 비교 중심-)

  • Yang, Yong-Hyeon;You, Yen-Yoo
    • Journal of Digital Convergence
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    • v.12 no.11
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    • pp.215-223
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    • 2014
  • To provide evidence of bank's management consulting effect on client firms' performance and contribution to the bank, this study adopts Matching Sample Design and OLS regression using financial and consulting data from A Bank, which allowed us for empirically testing bank's management consulting effect on client firms. Specifically, We examine difference between ante-post performance of consulting client firms and difference between performance of consulting client firms and the other client firms. Empirical results show that management consulting by a Bank can increase interdependency, while It does not cause significant improvement of growth, activity, and profitability. This result provides further understanding of effect of management consulting by a bank on consulting client firms and some implication which banks should consider for management consulting.

Evaluation of a New Workplace Protection Factor―Measuring Method for Filtering Facepiece Respirator

  • Sun, Chenchen;Thelen, Christoph;Sanz, Iris Sancho;Wittmann, Andreas
    • Safety and Health at Work
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    • v.11 no.1
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    • pp.61-70
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    • 2020
  • Background: This study aims to assess whether the TSI PortaCount (Model 8020) is a measuring instrument comparable with the flame photometer. This would provide an indication for the suitability of the PortaCount for determining the workplace protection factor for particulate filtering facepiece respirators. Methods: The PortaCount (with and without the N95-CompanionTM) was compared with a stationary flame photometer from Moores (Wallisdown) Ltd (Type 1100), which is a measuring instrument used in the procedure for determining the total inward leakage of the particulate filtering facepiece respirator in the European Standard. Penetration levels of sodium chloride aerosol through sample respirators of two brands (A and B) were determined by the two measuring systems under laboratory conditions. For each brand, thirty-six measurements were conducted. The samples were split into groups according to their protection level, conditioning before testing, and aerosol concentration. The relationship between the gauged data from two measuring systems was determined. In addition, the particle size distribution inside the respirator and outside the respirator was documented. Linear regression analysis was used to calculate the association between the PortaCount (with and without the N95-CompanionTM) and the flame photometer. Results: A linear relationship was found between the raw data scaled with the PortaCount (without N95-CompanionTM) and the data detected by the flame photometer (R2 = 0.9704) under all test conditions. The distribution of particle size was found to be the same inside and outside the respirator in almost all cases. Conclusion: Based on the obtained data, the PortaCount may be applicable for the determination of workplace protection factor.

PREDICTION OF SEVERE ACCIDENT OCCURRENCE TIME USING SUPPORT VECTOR MACHINES

  • KIM, SEUNG GEUN;NO, YOUNG GYU;SEONG, POONG HYUN
    • Nuclear Engineering and Technology
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    • v.47 no.1
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    • pp.74-84
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    • 2015
  • If a transient occurs in a nuclear power plant (NPP), operators will try to protect the NPP by estimating the kind of abnormality and mitigating it based on recommended procedures. Similarly, operators take actions based on severe accident management guidelines when there is the possibility of a severe accident occurrence in an NPP. In any such situation, information about the occurrence time of severe accident-related events can be very important to operators to set up severe accident management strategies. Therefore, support systems that can quickly provide this kind of information will be very useful when operators try to manage severe accidents. In this research, the occurrence times of several events that could happen during a severe accident were predicted using support vector machines with short time variations of plant status variables inputs. For the preliminary step, the break location and size of a loss of coolant accident (LOCA) were identified. Training and testing data sets were obtained using the MAAP5 code. The results show that the proposed algorithm can correctly classify the break location of the LOCA and can estimate the break size of the LOCA very accurately. In addition, the occurrence times of severe accident major events were predicted under various severe accident paths, with reasonable error. With these results, it is expected that it will be possible to apply the proposed algorithm to real NPPs because the algorithm uses only the early phase data after the reactor SCRAM, which can be obtained accurately for accident simulations.