• Title/Summary/Keyword: empirical correlations

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A Empirical Study on Influencing Factors of Fire Official's Job Satisfaction as a Inner Client - With Special Reference to Daejeon Metropolitian City's Case - (내부고객으로서 소방공무원의 직무만족 영향요인에 관한 경험적 연구 - 대전광역시 사례를 중심으로 -)

  • Song, Yong-Sun
    • Fire Science and Engineering
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    • v.22 no.2
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    • pp.70-83
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    • 2008
  • This study examine the factors of job satisfaction and searches wheather job satisfaction has relation to fire official's performance of work. The purpose of this study is suggest management that can promote job satisfaction of fire officials. This is based on the survey from fire officials in Daejeon metropolitian city. For testing hypothesis casual analysis is needed the major methods of this study is used factors analysis, correlations analysis, and multi regression analysis. Following are the major finds. There are statistically significant relations between 5 independent variables (job motivations, organizational management factors, staff management factors, work environment factors, human relations factors) and job satisfaction of fire officials. But, there are no statistically significant relations between demographic variable(gender, age, position, years of serving and job satisfaction).

Prediction and Experiment of Pressure Drop of R22, R407C and R410A on Design Conditions of Condenser (응축기의 설계조건에서 R22, R407C, R410A의 압력강하 예측 및 실험)

  • 김창덕;박일환;이진호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.1
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    • pp.42-53
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    • 2004
  • An experimental study on the refrigerant-side pressure drop of slit fin-tube heat exchanger has been carried out. A comparison was made between the predictions of previously proposed empirical correlations and experimental data for the pressure drop on design conditions of condenser in micro-fin tube for R22 and its alternatives, R407C (R32/125/134a, 23/25/52 wt.%) and R410A (R32/125, 50/50 wt.%). Experiments were carried out under the conditions of inlet refrigerant temperature of 6$0^{\circ}C$ and mass fluxes varying from 150 to 250 kg/$m^2$s for R22, R407C and R410A. The inlet air conditions are dry bulb temperature of 35$^{\circ}C$, relative humidity of 40% and air velocity varying from 0.68 to 1.43 m/s. Experiments show that pressure drop for R410A and R407C were 17.8∼20.2% and 5∼6.8% lower than those of R22 respectively for the degree of subcooling of 5$^{\circ}C$. For the mass fluxes of 200∼250 kg/$m^2$s, the deviation between the experimental and predicted values for the pressure drop was less than $\pm$20% for R22, R407C and R410A.

A Comparison of Piagetian and Psychometric Assessments of Intelligence (Piaget식 지능과 심리측정적 지능간의 비교 분석)

  • Wang, Young Hee
    • Korean Journal of Child Studies
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    • v.4
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    • pp.37-51
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    • 1983
  • The purpose of this study was the investigation of theoretical and empirical relationships between Piagetian and psychometric assessments of intelligence. Specifically, the factor structure of Piagetian-type scales, the relationship between Piagetian scales and psychometric intelligence tests, and differences in the factor structure of Piagetian and psychometric assessments of intelligence were studied. The subjects of this stuby were 70 children (35 boys and 35 girls) in the 1st grade of an elementary school in Seoul The Piagetian-type scales and the K-WISC were administered individually, and the General Intelligence Test was administered to groups of children. Statistical analysis of the obtained data consisted of the SPSS Computer program including factor analysis and Pearson's product moment correlation coefficient. The Piagetian-type scales were found to consist of three factors, which accounted for 55 percent of the total common-factor variance. Factor-I was a factor indicating "conservation". Factor-II was a factor indicating "moral judgements". Factor-III was a factor indicating "classification and identity". Correlations between subtests of psychometric tests and Piagetian scales were relatively low or moderate. Relations between IQs assessed by the psychometric tests and Piagetian scales were also relativeyly low or moderate. Eight factors were extracted from the joint factor analysis of psychometric intelligence tests and Piagetian scales, and they accounted for 67 percent of the total common-factor variance. Factors-I, II, III, and V consisted of subtests of psychometric assessments, and Factors-IV, VI, VII and VIII were composed of Piagetian scales. Factor-I was a factor for "reasoning ability based upon language". Factor-II was a factor for "performance ability". Factor-III was a factor for "grouping ability". Factor-IV was a factor for "conservation". Factor-V was a factor indicating "symbol and language usage ability". Factor- VI was a factor indicating "moral judgments". Factor-VII was a factor indicating "length consevation". Factor-VIII was a factor indicating "classification and identity".

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Evaporation Heat Transfer and Pressure Drop Characteristics of R-134a in the Oblong Shell and Plate Heat Exchanger

  • Park, Jae-Hong;Kim, Young-Soo
    • Journal of Mechanical Science and Technology
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    • v.18 no.12
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    • pp.2284-2293
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    • 2004
  • The evaporation heat transfer coefficient h$\_$r/ and frictional pressure drop Δp$\_$f/ of refrigerant R-134a flowing in the oblong shell and plate heat exchanger were investigated experimentally in this study. Four vertical counterflow channels were formed in the oblong shell and plate heat exchanger by four plates of geometry with a corrugated sinusoid shape of a 45 chevron angle. Upflow of refrigerant R-134a boils in two channels receiving heat from downflow of hot water in other channels. The effects of the refrigerant mass flux, average heat flux, refrigerant saturation temperature and vapor quality of R-134a were explored in detail. Similar to the case of a plate heat exchanger, even at a very low Reynolds number, the flow in the oblong shell and plate heat exchanger remains turbulent. The results indicate that the evaporation heat transfer coefficient h$\_$r/ and pressure drop Δp$\_$f/ increase with the vapor quality. A rise in the refrigerant mass flux causes an increase in the h$\_$r/ and Δp$\_$f/. But the effect of the average heat flux does not show significant effect on the h$\_$r/ and Δp$\_$f/. Finally, at a higher saturation temperature, both the h$\_$r/ and Δp$\_$f/ are found to be lower. The empirical correlations are also provided for the measured heat transfer coefficient and pressure drop in terms of the Nusselt number and friction factor.

Assessment of the unconfined compression strength of unsaturated lateritic soil using the UPV

  • Wang, Chien-Chih;Lin, Horn-Da;Li, An-Jui;Ting, Kai-En
    • Geomechanics and Engineering
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    • v.23 no.4
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    • pp.339-349
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    • 2020
  • This study investigates the feasibility of using the results of the UPV (ultrasonic pulse velocity) test to assess the UCS (unconfined compressive strength) of unsaturated soil. A series of laboratory tests was conducted on samples of unsaturated lateritic soils of northern Taiwan. Specifically, the unconfined compressive test was combined with the pressure plate test to obtain the unconfined compressive strength and its matric suction (s) of the samples. Soil samples were first compacted at the designated water content and subsequently subjected to the wetting process for saturation and the following drying process to its target suction using the apparatus developed by the authors. The correlations among the UCS, s and UPV were studied. The test results show that both the UCS and UPV significantly increased with the matric suction regardless of the initial compaction condition, but neither the UCS nor UPV obviously varied when the matric suction was less than the air-entry value. In addition, the UCS approximately linearly increased with increasing UPV. According to the investigation of the test results, simplified methods to estimate the UCS using the UPV or matric suction were established. Furthermore, an empirical formula of the matric suction calculated from the UPV was proposed. From the comparison between the predicted values and the test results, the MAPE values of UCS were 4.52-9.98% and were less than 10%, and the MAPE value of matric suction was 17.3% and in the range of 10-20%. Thus, the established formulas have good forecasting accuracy and may be applied to the stability analysis of the unsaturated soil slope. However, further study is warranted for validation.

An Empirical Study on Business Ethics in Manufacturing Sector

  • Ratna, Rajnish;Chawla, Saniya;Arora, Isha
    • Asia-Pacific Journal of Business
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    • v.4 no.2
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    • pp.21-30
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    • 2013
  • Ethics involves distinguishing between what is right or wrong thereby making a correct choice. An organization should treat its internal as well as external stakeholders ethically. This research gives valuable insights on the prevailing ethical climate and potential organizational challenges in institutionalizing ethics and its management in the manufacturing sector. The present study is designed to analyze four parameters of ethical climate in the manufacturing sector with reference to different managerial levels, to identify the critical factor of the ethical code of conduct and to find correlations between four parameters of ethical climate. Descriptive research has been used and data are collected from 200 employees of three Indian companies of manufacturing sector using a well designed questionnaire. Analyzing data with SPSS, It has been found that overall good number of people believe that MBE (Management of Business Ethics) process is well implemented. People are well aware and trained and involved in the ethical process. Senior management is very much committed to promote the ethical environment in the organization and thus company values are well communicated to the employees. Concern resolution mechanism is well established in the organization. MBE in the organization is more prevalent in higher-level employees. Senior management commitment and reinforcement is very critical for CoC (code of conduct). Correlation between all the 4 parameters is positive and significant. But the parameters are not highly correlated with each other. Organizations need to work upon these parameters to promote an ethical climate in the organization by awarding or felicitating exemplary ethical behavior. More emphasis should be given on senior management commitment and reinforcement of the ethical behavior across all levels.

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Evaluation of Air-side Friction Characteristics on Design Conditions of Slit Fin and Tube Heat Exchanger (슬릿휜-관 열교환기의 설계조건에서 공기측 압력강하 산출)

  • Cho, Sung-Chul;Kim, Chang-Duk;Kim, Chang-Eob;Kwon, Jeong-Tae;Lim, Hyo-Jae
    • Journal of Energy Engineering
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    • v.16 no.3
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    • pp.149-154
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    • 2007
  • An experimental study on the air-side pressure drop of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side pressure drop in the literature is not based on a consistent approach. This paper focuses on method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface pressure drop estimation in fin-tube heat exchanger. A comparison was made between the predictions of previously proposed empirical correlations and experimental data for the air-side pressure drop on design conditions of condenser and evaporator. Results are pre-sented as plots of friction f-factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of $150{\sim}250\;kg/m^2s$ with air flows at velocity ranges from 0.38 m/s to 1.6 m/s.

Investigation on Minimum Film Boiling Point of Highly Heated Vertical Metal Rod in Aqueous Surfactant Solution (계면활성제 수용액 내 고온 수직 금속봉의 최소막비등점에 대한 연구)

  • Lee, Chi Young;Kim, Jae Han
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.9
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    • pp.597-603
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    • 2017
  • In this study, experiments were conducted on the MFB(minimum film boiling) point of highly heated vertical metal rod quenched in aqueous surfactant solution at various temperature conditions. The aqueous Triton X-100 solution(100 wppm) and pure water were used as the liquid pool. Their temperatures ranged from $77^{\circ}C$ to $100^{\circ}C$. A stainless steel vertical rod of initial center temperature of $500^{\circ}C$ was used as a test specimen. In both liquid pools, as the liquid temperature decreased, the time to reach the MFB point decreased with a parallel increase in the temperature and heat flux of the MFB point. However, over the whole present temperature range, in the aqueous Triton X-100 solution, the time to reach the MFB point was longer, while the temperature and heat flux of the MFB point were reduced when compared with pure water. Based on the present experimental data, this study proposed the empirical correlations to predict the MFB temperature of a high temperature vertical metal rod in pure water and in aqueous Triton X-100 solution.

Effects of Variable Properties on the Laminar Heat Transfer around a Circular Cylinder in a Uniform Flow (물성치의 변화를 고려한 균일유동 중에 있는 원형 실린더 주위의 층류 열전달)

  • 강신형;홍기혁;고상근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.6
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    • pp.1584-1595
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    • 1993
  • Many researches were carried out to estimate heat transfer rate on a circular cylinder in a uniform flow. Various empirical correlations were suggested in the past through expermental studies, however there are considerable discrepancies in the estimated values of heat transfer coefficient. Effects of variable properties of fluid on the heat transfer between a circular cylinder and the external uniform flow were numerically investigated in the present study. The flow and temperature fields were solved using a finite volume method for the uniform flow temperature of 200-900K and the wall temperature of 300-900K. The cold as well as the hot cylinders in the uniform flow of constant temperature were investigated. A unified correlation was obtained for the both cases.

Analysis of the Factors Affecting MIS Success : Focusing on the Small Business of Manufacturing Industry in Korea (경영정보시스템의 성공과 실패에 대한 요인 분석 : 우리나라 제조업 분야의 중소기업을 중심으로)

  • Kang, Byeong-Gu
    • Asia pacific journal of information systems
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    • v.5 no.1
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    • pp.236-257
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    • 1995
  • Not much attention has been paid to the characteristics of successful MIS in small business in Korea. This study compares the characteristics of successful MIS with those of less successful MIS of manufacturing industry in Korea in terms of micro level, macro level, and personal level. The micro level consists of those variables relating to the system development and maintenance while the macro level consists of the environmental variables relating to the information systems. The personal level measures a personal EDP experience. A mail survey was sent to small manufacturing companies to collect the data for the hypothesis tests. And 81 usable questionnaires were returned for data analysis. This study performs the validity of the categorization of variables in terms of three levels. The results shows that this categorization is appropriate but the personal level. As the personal experiences of EDP in Korea used to come up with those of the organization, the variables in the personal level have high correlations with those in the macro level in empirical testing. As the personal level, however, is different dimension from the macro level in theoretical aspect, the level is maintained separately throughout the study. The data were analyzed with MANOVA and two group discriminant analysis. The analyses reveal that the characteristics of successful MIS are different from those of less successful MIS in terms of three levels. And the micro level is more important than the macro level to develop successful MIS. That is because the organizations have relatively few experience in dealing with information systems, they have not developed unique information systems which are adjusted to their organizational characteristics. Those findings seems to be important determinants of success for the MIS in a firm.

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