• Journal of Korean Society for Atmospheric Environment
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• v.11 no.1
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• pp.85-93
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• 1995

Measurements of ground level ozone concentrations were made in a rural area of Chongwon (Choongbook Province) from June 1993 to July 1994. High values frequently exceeding 100 ppb (ambient air qualyty standard of Korea) were recorded. High ozone concentrations in the boundary layer were primarily correlated with the several meteorological parameters in warm seasons: pressure, radiation, temperature, precipitation and wind velocity. The annual average concentration of ozone at Chongwon was 17ppb, and this value was relatively higher than those for other cities in Korea. O$\_$3/ concentrations were observed to increase when the ridge of a surface anticyclone was passing over the region, and maximum values(.geq.100 ppb) were observed on the rear sides of high pressure centers and in the warm sectors of cyclones(well head of cold fronts). The ozone concentrations had a negative correlation with the concentration of primary pollutants(e.g., total hydrocarbons).

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.51-54
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• 1992

In this paper, we quantitatively evaluated the anxiety data from humans in an anxiety state. It has been reported that the electric signals of human can be correlated with their emotional state. We chose heart rate, respiration rate, temperature and skin conductance as the anxiety parameters. For experiment protocol, the subject was given exercising load to induce the anxiety state and the exercise was done using the FITRON Cycle Ergometer. We divided the data into three stages: rest period, exercise period, and recovery period. During evaluation, We counted the heart rate, slope of heart rate, temperature change, and the skin conductance.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.4
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• pp.222-228
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• 2012

Adiponectin is secreted specifically by adipose tissue and regulates lipid and glucose metabolism. In addition, adiponectin has been found to inhibit inflammatory process and possibly atherogenesis. This study was done to compare hematological parameters, serum lipids with serum adiponectin level according to body mass index (BMI) and gender in eighty eight Korean adults aged 40 to 68. In this study, the association between serum adiponectin and other variables including RBC counts, hemoglobin, hematocrit and albumin were investigated. RBC, hemoglobin status, was inversely associated with serum adiponectin levels in normal adult women. Adiponectin levels were significantly lower in men than women (p<0.01). In men, serum adiponectin levels were negatively correlated with body mass index (BMI) (p<0.05). However, no correlations were found in women. These results might imply that the regulation of key adipokines such as adiponectin might be a strategy for the prevention or treatment of obesity-associated diseases.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.9
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• pp.744-750
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• 2003

The performance of adiabatic capillary tubes are measured to provide the database for a generalized correlation. Test conditions and capillary tube geometries are selected to cover a wide range typically observed in air-conditioning and heat pump applications. Based on extensive experimental data for R22, R290, and R407C measured in this study, a generalized correlation for refrigerant flow rate in adiabatic capillary tubes is developed by implementing dimensionless parameters for tube inlet conditions, capillary tube geometry, and refrigerant properties. The correlation yields good agreement with the present data for R22, R290, and R407C with average and standard deviations of 0.9% and 5.0%, respectively. In addition, approximately 97% of the data for Rl2, R134a, R152a, R410A, and R600a obtained in the open literature are correlated within a relative deviation of $\pm$ 15%.

• Journal of Powder Materials
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• v.7 no.2
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• pp.63-70
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• 2000

Thermal spray coating process has proven to be effective at producing hard, dense, wear resistance coatings on the relatively mild substrates. Among several spraying techniques, HVOF (High Velocity Oxygen Fuel) and plasma coating processes, which are preferentially used for the wear resistance application such as capstans, have been applied in this study. The effects of pre-treatment, it-process and post-treatment parameters on the wear and mechanical properties of WC+12%Co, Cr3C2 and Al2O3 powder coatings have been investigated and correlated with the microstructures. The results indicated that the carbide coating was more preferable to the oxide coatings and the post-treatments consisting of vacuum annealing and sealing on carbide coatings led to significant improvements in wear resistance, adhesive strength and coating phase stabilization over the other processing techniques in this application.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.11
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• pp.1207-1218
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• 1990

The lack of persistent excitation (PE) can be the reason of freezing in the recursive least square estimators and the covariance windup in the exponential weighted least square estimators. We present a theoretical analysis of these phenomena and a simple method to check the exciting condition in real time. Using these results and under some conditions such as slowly time varying Plant and a tracking problem for set point, a robust self-tuning regulators without PE is proposed. In this algorithm, when PE is not satisfied, only plant gain is estimated, and then the system parameters are corrected by it. It is shown that the gain adaptive scheme makes the robustness to be improved against modeling error, off-set, and correlated noise etc, by the results of analysis and simulations.

• Journal of the Korean Data and Information Science Society
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• v.26 no.2
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• pp.525-533
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• 2015

Modern production process is a very complex structure combined observations which are correlated with several factors. When the error signal occurs in the process, it is very difficult to know the root causes of an out-of-control signal because of insufficient information. However, if we know the time of the change, the system can be controlled more easily. To know it, we derive a maximum likelihood estimator (MLE) of the change point in a process when observations are from a multivariate IMA(1,1) process by monitoring residual vectors of the model. In this paper, numerical results show that the MLE of change point is effective in detecting changes in a process.

• Smart Structures and Systems
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• v.6 no.9
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• pp.991-1005
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• 2010

The key to detecting damage to civil engineering structures is to find an effective damage indicator. The damage indicator should promptly reveal the location of the damage and accurately identify the state of the structure. We propose to use the distance measures of low-order AR models as a novel damage indicator. The AR model has been applied to parameterize dynamical responses, typically the acceleration response. The premise of this approach is that the distance between the models, fitting the dynamical responses from damaged and undamaged structures, may be correlated with the information about the damage, including its location and severity. Distance measures have been widely used in speech recognition. However, they have rarely been applied to civil engineering structures. This research attempts to improve on the distance measures that have been studied so far. The effect of varying the data length, number of parameters, and other factors was carefully studied.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.461-472
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• 1995

The interaction of laminar mixed convection and surface radiation in a two-dimensional channel with an array of rectangular blocks is analyzed numerically. Three blocks are maintained at high temperature and the other bottom and top horizontal walls are insulated. Discrete ordinate method(DOM) is introduced to analyze the radiative heat transfer. The effects of the variations of Reynolds number and channel specifications on the heat transfer characteristics are investigated. The average Nusselt numbers along the block surfaces are correlated and presented in terms of Reynolds number and dimensionless geometric parameters such as the block spacing, height and channel spacing. For the conditions considered in this study, average Nusselt numbers along the block surfaces are strongly influenced by the channel spacing and Reynolds number but weakly influenced by the block spacing and block height.

• The Pure and Applied Mathematics
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• v.27 no.2
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• pp.71-81
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• 2020

Multicollinearity is a common problem in linear regression models when two or more regressors are highly correlated, which yields some serious problems for the ordinary least square estimates of the parameters as well as model validation and interpretation. In this paper, first the problem of multicollinearity and its subsequent effects on the linear regression along with some important measures for detecting multicollinearity is reviewed, then the role of eigenvalues and eigenvectors in detecting multicollinearity are bolded. At the end a real data set is evaluated for which the fitted linear regression models is investigated for multicollinearity diagnostics.