• 한국유통학회지:유통연구
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• 제1권1호
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• pp.239-258
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• 1996

This study deals with the measurement of relational norms, a safeguard for sustained exchange relationshipsim marketing channel systems. Here, the relational norm items are hypothesized to have a second-order factor model, in which mine observed items originate from the three first-order factors and the first order factors in turn originate from a second-order factor. The three first order construe comprising a higher order norm are mutuality(equity in the distribution of benefits and burdens over the course of the exchange on a long term basis), flexibility(expectation of friendly adaption for possible circumstance changes), and solidarity (the degree to which the preservation of the unique and continuing relationship is internalized by the exchange partners as being important in and of itself). 113 research questionnaires are obtained from four industries such as construction, telecommunication, iron, and electric ＆ electronic industries, Reliability and nomological. discriminant validity are tested, and in using the confirmatory factor analysis of Lisrel 7.16, and the chi-square difference test it is tested which has a better satisfactory fit to the data, the first-order model or the second-order one. The results of this study indicates that relational norms have a second order construct. In the electric and electronic industry the model as a while has a satisfactory fit to the data and the relevant first- and second-order factor loading to the mutuality is not significant. Same Results are happened to the flexibility in the telecommunication industry and to the mutuality and flexibility in the inn industry. In sum, the model lends support to our construct, but it is difficult to apply the measurement model to all kinds of industries.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.17-21
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• 2014

This paper presents the effects of the time delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a time delay model. In this paper, the time delay is considered as the computational time delay that is assumed to be as much as the sampling time. As the time delay increases, the maximal available stiffness of a virtual wall model is reduced reversely. The relation among the time delay and the maximum available stiffness, the mass and the damper of the haptic device are analyzed using the MATLAB simulation.

• 대한기계학회논문집B
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• 제31권7호
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• pp.620-627
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• 2007

In this paper, we adapt a modified internal energy non-equilibrium first-order extrapolation thermal boundary condition to the thermal lattice Boltzmann model (TLBM). This model is the double populations approach to simulate hydrodynamic and thermal fields. The bounce-back boundary condition which is a traditional boundary condition of lattice Boltzmann method has only a first order in numerical accuracy at the boundary and numerical instability. A non-equilibrium first-order extrapolation boundary condition has been verified to be of better numerical stability than the bounce-back boundary condition and this boundary condition is proved to be of second-order accuracy for the flat boundaries. The two-dimensional natural convection flow in a square cavity with Pr=0.71 and various Rayleigh numbers are simulated. The results are found to be in good agreement with those of previous studies.

• 한국식품저장유통학회지
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• 제18권3호
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• pp.423-428
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• 2011

주요 식중독균인 E. coli O157:H7, L monocytogenes, S. aureus, S. Typhimurium과 S. Enteritidis를 주어진 이산화염소수 농도에서 시간별로 처리한 inactivation data를 first-order kinetic model과 Weibull model을 이용하여 kinetic parameter를 비교, 분석하였다. 그 결과 Weibull model이 first-order kinetic model보다 inactivation kinetic data에 더 적합한 것을 보였다. 또한 특정 농도의 이산화염소수에서 처리한 survival plot의 tR values(특정 이산화염소수 농도에서 미생물 90%를 감소시키기 위해 필요한 시간)는 Weibull model을 적용 시, E. coli O157:H7가 5 ppm에서 2.49 min, L. monocytogenes가 5 ppm에서 1.47 min, S. aureus가 5 ppm에서 0.94 min, S. Typhimurium이 1 ppm에서 0.87 min 그리고 S. Enteritidis가 1 ppm에서 0.08 min으로 측정 되었다.

• 융복합기술연구소 논문집
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• 제3권2호
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• pp.23-29
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• 2013

When a human operator interacts with a virtual wall that is modeled as a virtual spring model, the lager the stiffness of the virtual spring is, the more realistic the operator feels that the virtual wall is. In the previous studies, it is shown that the maximum available stiffness of a virtual spring to guarantee the stability can be increased when the first-order-hold method is applied, however the effects of a human impedance on the stability are not considered. This paper presents the effects of a human impedance on stability of haptic system with a virtual spring and a first-order-hold (FOH) method. The human impedance model is modeled as a linear second-order system model. The relations between the maximum available stiffness of a virtual spring and the human impedance such as a mass, a damping and a stiffness are analyzed through the MATLAB simulation. It is shown that the maximum available stiffness is proportional to the square root of the human mass or damping respectively.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.37-42
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• 2015

This paper presents the effects of the computational time-varying delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a computational time-varying delay model. In this paper, the maximum of the computational time-varying delay is assumed to be as much as the sampling time. Using the simulation, it is analyzed how the sample-hold methods and the computational time-varying delay affect the maximum available stiffness. As the maximum of computational time-varying delay increases, the maximal available stiffness of a virtual wall model is reduced.

• 상하수도학회지
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• 제25권6호
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• pp.971-979
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• 2011

Palm Oil Mill Effluent (POME) is the mixed organic wastewater generated from palm oil industry. In this study, kinetic analysis with treating POME in an anaerobic hybrid reactor (AHR) was performed. Therefore, the AHR was monitored for its performances with respect to the changes of COD concentrations and hydraulic retention time (HRT). Batch tests were performed to find out the substrate removal kinetics by granular sludge from POME. Modified Stover Kincannon, First-order, Monod, Grau second-order kinetic models were used to analyze the performance of reactor. The results from the batch test indicate that the substrate removal kinetics of granular sludge is corresponds to follow Monod's theory. However, Grau second-order model were the most appropriate models for the continuous test in the AHR. The second order kinetic constant, saturation value constant, maximum substrate removal rate, and first-order kinetic constant were 2.60/day, 41.905 g/L-day, 39.683 g/L-day, and 1.25/day respectively. And the most appropriate model was Grau second-order kinetic model comparing the model prediction values and measured COD concentrations of effluent, whereas modified Stover-Kincannon model showed the lowest correlation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.630-633
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• 2004

Generally, component and FR-4 board are connected by solder joint. Because material properties of components and FR-4 board are different, component and FR-4 board show different coefficients of thermal expansion (CTE) and thus strains in component and board are different when they are heated. That is, the differences in CTE of component and FR-4 board cause the dissimilarity in shear strain and BGA solder joint s failure. The first order Taylor series expansion of the limit state function incorporating with thermal fatigue models is used in order to estimate the failure probability of solder joints under heated condition. A model based on plastic-strain rate such as the Coffin-Manson Fatigue Model is utilized in this study. The effects of random variables such as frequency, maximum temperature, and temperature variations on the failure probability of the BGA solder joint are systematically investigated by using a failure probability model with the first order reliability method(FORM).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.345-347
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• 2004

In small signal stability analysis of power systems, eigenvalue analysis is the most useful method and the detailed modeling of generator has an important effect to the eigenvalues. Generator full model is used for precise dynamic analysis of generators and controllers while two-axis model is used for multi-machine systems because of the reduced order of the state matrix. Also, the eigenvalue sensitivity coefficients are used for optimizing controller parameters to improve system stability. This paper compare the first and second order eigenvalue sensitivity coefficients of controllers using generator full model with those of two-axis model. As a result of an example, the estimated eigenvalues using the first and the second eigenvalue sensitivity coefficients using generator full model is very close to those of state matrix. Also the error ratios throughout a wide range of controller parameters is less than $1\%$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.678-683
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• 2008

Moment-based reliability analysis is the method to calculate reliability using Pearson System with first-four raw moments obtained from simulation model. But it is too expensive to calculate first four moments from complicate simulation model. To overcome this drawback the MD(multiplicative decomposition) method which approximates simulation model to kriging metamodel and calculates first four raw moments explicitly with multiplicative decomposition techniques. In general, kriging metamodel is an interpolation model that is decomposed of global model and local model. The global model, in general, can be used as the constant global model, the 1st order global model, or the 2nd order global model. In this paper, the influences of global models on the accuracy and robustness of raw moments are examined and compared. Finally, we suggest the best global model which can provide exact and robust raw moments using MD method.