• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.119-128
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• 2010

Mode choice behavior is associated with travelers' latent behavior that is an unobservable preference to travel behavior or mode characteristics. This paper specifically addresses the problem of unobservable factors, that is latent behavior, in mode choice models. Consideration of latent behavior in mode choice models reduces the errors that come from unobservable factors. In this study, the authors defined the latent variables that mean a quantitative latent behavior factors, and developed the combined RP/SP model with latent variables using the mode choice behavior survey data. The data has traveler's revealed preference of existent modes along the Han River and stated preference of new water transit on the Han River. Also, The data has travelers' latent behavior. Latent variables were defined by factor analysis using the latent behaviour data. In conclusion, it is significant that the relationship between traveler's latent behavior and mode choice behavior. In addition, the goodness-of-fit of the mode choice models with latent variables are better than the model without latent variables.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1144-1153
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• 2015

The resonant mechanism of reradiation interference (RRI) over 1.7MHz from power transmission lines cannot be obtained from IEEE standards, which are based on researches of field intensity. Hence, the resonance is ignored in National Standards of protecting distance between UHV power lines and radio stations in China, which would result in an excessive redundancy of protecting distance. Therefore, based on the generalized resonance theory, we proposed the idea of applying model-based parameter estimation (MBPE) to estimate the generalized resonance frequency of electrically large scattering objects. We also deduced equation expressions of the generalized resonance frequency and its quality factor Q in a lossy open electromagnetic system, i.e. an antenna-transmission line system in this paper. Taking the frequency band studied by IEEE and the frequency band over 1.7 MHz as object, we established three models of the RRI from transmission lines, namely the simplified line model, the tower line model considering cross arms and the line-surface mixed model. With the models, we calculated the scattering field of sampling points with equal intervals using method of moments, and then inferred expressions of Padé rational function. After calculating the zero-pole points of the Padé rational function, we eventually got the estimation of the RRI’s generalized resonant frequency. Our case studies indicate that the proposed estimation method is effective for predicting the generalized resonant frequency of RRI in medium frequency (MF, 0.3~3 MHz) band over 1.7 MHz, which expands the frequency band studied by IEEE.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.21-31
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• 2010

In the architectural design technologies being changed recently, there is the study to develop the way that will enable the designers to get access logically to the processes of deciding the values of design factors which depend on the experience of the designers. This study, which is one part of those studies, has been carried out to develop the model that can decide the values logically for the design factors having the character that the design values are changed by the time variation out of design factors involved in the building energy saving design. As a result, the structure of the decision model which can decide the design values logically from the computer simulation that solve the problem by interpreting the real world as the probability distribution, has been established through this study. For the application and verification of these decision model, the case study has been carried out for the outdoor climate factors that stand for the design factors having the time variation.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.238-242
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• 2007

Square root models were developed for predicting the kinetics of growth of Listeria monocytogenes in sesame leaves as a function of temperature (4, 10, or $25^{\circ}C$). At these storage temperatures, the primary growth curves fit well ($R^2=0.898$ to 0.980) to a Gompertz equation to obtain lag time (LT) and specific growth rate (SGR). The square root models for natural logarithm transformations of the LT and SGR as a function of temperature were obtained by SAS's regression analysis. As storage temperature ($4-25^{\circ}C$) decreased, LT increased and SGR decreased, respectively. Square root models were identified as appropriate secondary models for LT and SGR on the basis of most statistical indices such as coefficient determination ($R^2=0.961$ for LT, 0.988 for SGR), mean square error (MSE=0.l97 for LT, 0.005 for SGR), and accuracy factor ($A_f=1.356$ for LT, 1.251 for SGR) although the model for LT was partially not appropriate as a secondary model due to the high value of bias factor ($B_f=1.572$). In general, our secondary model supported predictions of the effects of temperature on both LT and SGR for L. monocytogenes in sesame leaves.

• Journal of Information Technology Services
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• v.16 no.4
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• pp.15-31
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• 2017

This study analyzes 45 Korea IT service companies from 2012 to 2016 using DEA analysis. Large enterprises, medium enterprises and small and medium enterprises (SMEs). CCR model and BCC model were used for efficiency analysis. Among the various analytical objects, the decision objects which yield the maximum output with minimum input are compared with other analysis objects. The relative inefficiency was measured through this, and Technical Efficiency (TE), Pure Technology Efficiency (PTE), Scale Efficiency (SE), scale profit, reference frequency were analyzed. Also, we analyzed the Technology Gap Ratio (TGR), which is the distance between production function and Meta-Frontier for each firm, using Meta-Frontier analysis. Finally, the Tobit model is used to analyze the sources of efficiency and inefficiency. The inputs are assets, capital, and employees, and the output factor is sales. The analysis shows that large firms are achieving technological achievements more efficiently than small and medium enterprises. As a result, medium-sized enterprises and SMEs can improve efficiency overall through efficient operation of workforce and appropriate combination of inputs such as assets and capital. Also, as a result of the influence factor analysis, it was found that the ratio of the managed asset ratio and the management cost ratio were significant factors influencing the efficiency of the IT service companies. This study suggests the efficiency analysis using DEA for many Korea IT service companies. Inefficient parts of each company are classified according to size and technology. Also, we identify the most efficient companies and analyze the causes of those companies whose profits are lower than their size.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.209-220
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• 2016

Although organizations are providing information security policy, education and support to guide their employees in security policy compliance, accidents by non-compliance is still a never ending problem to organizations. This study investigates the factors that influence employees' information security policy compliance behavior using elements of Triandis model. We analyzed the relationships among Triandis model's factors using PLS(Partial Least Squares). The result of the hypothesis tests shows that organization can induce individual's information security policy compliance intention and behavior by information security policy and facilitating conditions that support it, and proves the importance of members' expected value, habit and affect about information security compliance. This study is significant in a way that it applies Triandis model in the field of information security, and presents direction for members' information security behavior, and will be able to provide measures to establish organization's information security policy and increase members' compliance behavior.

• Atmosphere
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• v.29 no.5
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• pp.537-550
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• 2019

To analyze the observation environment of solar radiation stations operated by the Korea Meteorological Administration (KMA), we analyzed the skyline, Sky View Factor (SVF), and solar radiation due to the surrounding topography and artificial structures using a Digital Elevation Model (DEM), 3D camera, and solar radiation model. Solar energy shielding of 25 km around the station was analyzed using 10 m resolution DEM data and the skyline elevation and SVF were analyzed by the surrounding environment using the image captured by the 3D camera. The solar radiation model was used to assess the contribution of the environment to solar radiation. Because the skyline elevation retrieved from the DEM is different from the actual environment, it is compared with the results obtained from the 3D camera. From the skyline and SVF calculations, it was observed that some stations were shielded by the surrounding environment at sunrise and sunset. The topographic effect of 3D camera is therefore more than 20 times higher than that of DEM throughout the year for monthly accumulated solar radiation. Due to relatively low solar radiation in winter, the solar radiation shielding is large in winter. Also, for the annual accumulated solar radiation, the difference of the global solar radiation calculated using the 3D camera was 176.70 MJ (solar radiation with 7 days; suppose daily accumulated solar radiation 26 MJ) on an average and a maximum of 439.90 MJ (solar radiation with 17.5 days).

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.3
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• pp.113-119
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• 2007

Developmental disability shows life-long behavioral abnormality with no significant physical malformation. This study was undertaken to develop an animal model for developmental disability by using two-factor approach. Lipopolysaccharide (LPS), a bacterial toxin, and NAN-190, a $5-HT_{1A}$ receptor antagonist, were administered to Sprague-Dawley rats on postnatal day (PND) 5 to induce inflammation and an altered 5-HT system, respectively. Long-term alteration of behavior occurred in the drug-treated groups. The LPS-treated group showed impaired motor coordination in the Rota-rod test. The LPS- treated or both LPS and NAN-190-treated groups showed impaired fore-paw muscle power in the wire maneuver test. These groups also showed decreased white matter volume and increased serotonergic fibers. The LPS and NAN-190-treated group also exhibited neurologic deficit in the placing reaction test and impaired equilibrium function in the tilt table test. The results showed that a variety of altered behaviors can be generated by two factor model, and suggested that combination of important etiologic factors and possible underlying defects is a promising strategy of establishing an animal model for developmental disabilities.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.10
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• pp.11-16
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• 2000

The SPICE model of the spiral inductor on silicon substrate which can be easily used for the RF IC design has been developed. In this proposed model the equivalent circuit element of the spiral inductor are defined by the layout and process parameters using the user-defined function and subcircuit of the SPICE. The total inductance is calculated using the subcircuit Li for the arbitrary turn i and the subcircuit Mij for two arbitrary turns. The model was verified by comparing the simulated data with the measured s-parameters, total inductance, and quality factor of the spiral inductor fabricated by the CMOS 0.8${\mu}m$ process. The proposed SPICE model of the spiral inductor is scalable and includes the effects of the silicon substrate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.457-470
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• 2016

Most CFD codes, that mainly adopt the heat partitioning model as the wall boiling model, have shown low accuracies in predicting the two-phase flow parameters of subcooled boiling phenomena under low pressure conditions. In this study, a number of subcooled boiling experiments in vertical channels were analyzed using a thermal-hydraulic component code, CUPID. The prediction of the void fraction distribution using the CUPID code agreed well with experimental data at high-pressure conditions; whereas at low-pressure conditions, the predicted void fraction deviated considerably from measured ones. Sensitivity tests were performed on the submodels for major parameters in the heat partitioning model to find the optimized sets of empirical correlations suitable for low-pressure subcooled flow boiling. The effect of the K-factor on the void fraction distribution was also evaluated.