• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.10
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• pp.1303-1310
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• 2001

In order to be applicable to the combustion modelling of stratified charged combustion like that of - lean burn and GDI engine, the correlations of laminar burring velocities fur several hydrocarbon fuels and methanol are needed over a wide range of equivalence ratio, pressure and temperature. In this study, these correlations are modeled in the 1311owing form based on the experimental and Muller\`s modeling results for several fuels, where $\alpha$, ξ, and ξ are functions of pressure and temperature, $S_{L}$ =$\alpha$ exp[-ξ($\Phi$-$\Phi$$_{m}$)$^{2}$ -exp {-ζ($\Phi$-$\Phi$$_{m}$)}-ζ($\Phi$-$\Phi$$_{m}$)]. By using the results calculated by PREMIX code with Sloane\`s detailed chemical reaction mechanism for propane, it is verified that the coefficients of the abode modeling can be determined by considering laminar burning velocity data only in a range of equivalence ratio less than $\Phi$$_{m}$. Therefore, Muller\`s modeling results can be adopted leer modeling of the pressure and temperature dependency. Compared with the results of the existing Keck'and Gulder's models, those of the present one showed the good agreement of the recent experimental data, especially in the range of lean and rich sides.s.des.s.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.3
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• pp.119-130
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• 2010

The Genetic Algorithm has been frequently applied by many researchers as one of the population surface modelling tool in estimating the regional population based on the gridded spatial system. Taking the East-Hwasung area as the case, this study first builds a gridded population data based on the KLIS and eAIS databases as well as municipal population survey data, and then constructs the attribute values of the explanatory variables by way of GIS tools. The GA model is run to maximize its fitness function measuring the correlation coefficient between the observed and predicted values of the 70 population cells. It is shown that the GA output predicted reasonably consistent and meaningful coefficient estimates for the explanatory variables of the model.

• Convergence Security Journal
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• v.10 no.4
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• pp.39-48
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• 2010

In a complex, secure IT system environment there will be groups of data that be segregated from one another, yet reside on the same system. Users of the system will have varying degrees of access to specific data. The Configuration Management(CM) of the information architecture, the physical architecture, user privileges and application security policies increases the complexity for operations, maintenance and security staff. This pager describes(current work to merge the capabilities of a network CM toll with those of a Computer Aided System Engineering(CASE) tool. The rigour of Systems Engineering(SE) modelling techniques can be used to deal with the complexities of multi-level information security. The SE logical and physical models of the same system are readily tailorable to document the critical components of both the information architecture and physical architecture that needs to be managed. Linking a user-friendly, physical CM tool with the extended capabilities of a CASE tool provide the basis for improved configuration management of secure IT systems.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.151-161
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• 2006

This paper has a goal to construct monitoring web GIS system which displays maps that are results of the fire detecting algorithms using MODIS image. To design and build more efficient system, foreign fire monitoring systems using satellite image are researched and analyzed. As a result of that, the information about interfaces and services provided by them are obtained. In concretely, new logical DFD is used to do a process modelling. ArcIMS 4.0 of ESRI, IIS 5.1 of Microsoft are utilized to build the web GIS System. In the aspects of data input and transfer, a specific module, which converts a binary image to a kind of vector file, is developed to adjust raster data to the web GIS system.

• Clean Technology
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• v.11 no.4
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• pp.165-170
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• 2005

The aim of this study is to provide vapor-liquid equilibrium (VLE) information for the study of process which directly synthesize dimethyl carbonate (DMC) from $CO_2$. For this study we collected some necessary VLE systems data of Methanol-Water, Methanol-DMC, $CO_2$-DMC, $CO_2$-Methanol, $CO_2$-Methanol, and performed VLE calculation with Peng-Robinson equation of state, Wong-Sandler mixing rules that widely used in chemical industry. These calculation results relatively agreed with VLE data well. Optimized Parameters of EoS given through this calculation will be used as some valuable information for fundamental study, process development and process optimization of DMC direct synthesis.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.1044-1051
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• 2002

This paper proposes a two-phase mathematical programming approach by considering classification gap to solve the proposed credit scoring problem so as to complement any theoretical shortcomings. Specifically, by using the linear programming (LP) approach, phase 1 is to make the associated decisions such as issuing grant of credit or denial of credit to applicants. or to seek any additional information before making the final decision. Phase 2 is to find a cut-off value, which minimizes any misclassification penalty (cost) to be incurred due to granting credit to 'bad' loan applicant or denying credit to 'good' loan applicant by using the mixed-integer programming (MIP) approach. This approach is expected to and appropriate classification scores and a cut-off value with respect to deviation and misclassification cost, respectively. Statistical discriminant analysis methods have been commonly considered to deal with classification problems for credit scoring. In recent years, much theoretical research has focused on the application of mathematical programming techniques to the discriminant problems. It has been reported that mathematical programming techniques could outperform statistical discriminant techniques in some applications, while mathematical programming techniques may suffer from some theoretical shortcomings. The performance of the proposed two-phase approach is evaluated in this paper with line data and loan applicants data, by comparing with three other approaches including Fisher's linear discriminant function, logistic regression and some other existing mathematical programming approaches, which are considered as the performance benchmarks. The evaluation results show that the proposed two-phase mathematical programming approach outperforms the aforementioned statistical approaches. In some cases, two-phase mathematical programming approach marginally outperforms both the statistical approaches and the other existing mathematical programming approaches.

• Journal of the Korean housing association
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• v.25 no.4
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• pp.31-38
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• 2014

The present research aimed at researching the relationships among place attachment, residential evaluations and satisfaction in a medium-sized post-communist Romanian city. Studies on post-communist cities are scarce and this research tried to fill that gap. This research is part of a government project that intended to significantly reform three medium-sized cities in the Western part of Romania and transform the urban space. Since the three of them are relatively small-sized and close spatially, the project intends to undertake massive reforms of the communications and services of the three cities. In this article, we report findings on the city of Hunedoara. A representative random sample was selected, and a total of 384 people were interviewed, with an overall reliability of the sample of 95%. The instruments used to gather the data were the Neighbourhood Perceived Environmental Quality Scale and a composite measure of place attachment was also included. The structure of each scale was checked using exploratory factor analysis. We tested alternative causal models using structural equations modelling. Our model showed a good fit to the data and explains satisfaction in the city adequately. Results show that satisfaction is directly predicted by the general evaluation of the city and by residential privacy. Residential noise and place attachment influence satisfaction indirectly. The results are discussed and some policy recommendations are formulated.

• Journal of Construction Engineering and Project Management
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• v.9 no.3
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• pp.1-21
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• 2019

The management of mega construction projects which incorporate a large number of stakeholders, technologies, data, work culture etc., is cumbersome. The experts in the construction arena advocate that interface management serves as a precise tool in resolving these conflict points due to the intricate nature of the construction projects. Interface management is a current trending management practice in the construction industry which is also a beneficiary to mega/fast track projects in enhancing the project performance. The main objective of this study is to validate a model for assessing the relationships among interface management, IT applications, project performance & project benefits. The mediating effect of interface management in relationship between project performance & interfacial factors was also investigated. The research model was validated using PLS-SEM (Partial Least Square-Structural Equation Modelling) approach. Data were collected from clients, contractors, consultants in large scale projects through questionnaire survey and smart-PLS software was used to analyse the conceptual model. The research model comprises eleven hypothesis and the significance of these hypothesis were tested using T- statistics values. The research implies that people/participants factor is greatly influenced by interface management with the path coefficient of 0.608 and also enhancement of project's schedule performance due to the interface management is strongly appealing (Path coefficient = 0.711). The results also reveal IT application is significantly associated with interface management practice (Path coefficient =0.723) and also the effect of IT application on project performance (schedule, cost, quality & safety) is successfully mediated through interface management practice. The practical application of this validated model was done through case study. The case study aims at measuring the impact of interface management on interfacial factors and role of interface management in improving the project performance in the construction organisations.

• Advances in environmental research
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• v.5 no.3
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• pp.153-167
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• 2016

We applied multilayer perceptron (MLP) and radial basis function (RBF) neural network in upstream and downstream water quality stations of the Karaj Reservoir in Iran. For both neural networks, inputs were pH, turbidity, temperature, chlorophyll-a, biochemical oxygen demand (BOD) and nitrate, and the output was dissolved oxygen (DO). We used an MLP neural network with two hidden layers, for upstream station 15 and 33 neurons in the first and second layers respectively, and for the downstream station, 16 and 21 neurons in the first and second hidden layer were used which had minimum amount of errors. For learning process 6-fold cross validation were applied to avoid over fitting. The best results acquired from RBF model, in which the mean bias error (MBE) and root mean squared error (RMSE) were 0.063 and 0.10 for the upstream station. The MBE and RSME were 0.0126 and 0.099 for the downstream station. The coefficient of determination ($R^2$) between the observed data and the predicted data for upstream and downstream stations in the MLP was 0.801 and 0.904, respectively, and in the RBF network were 0.962 and 0.97, respectively. The MLP neural network had acceptable results; however, the results of RBF network were more accurate. A sensitivity analysis for the MLP neural network indicated that temperature was the first parameter, pH the second and nitrate was the last factor affecting the prediction of DO concentrations. The results proved the workability and accuracy of the RBF model in the prediction of the DO.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.53-62
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• 2016

Extreme wind speeds at four sites including Mokpo, Gunsan, Incheon and Jeju near the Western Coast have been estimated with a tool of Monte Carlo simulation and typhoon data. Results of sensitivity analysis show that closeness between distance to the eye and the radius to maximum wind is most sensitive. While location angle and pressure deficit are sensitive too, but translation velocity is not. A standard typhoon, which results in extreme wind speeds having various return period, can be constructed by combination of parameter informations of each site. Then, with a numerical modelling of the typhoon, extreme surge heights having the same return period can also be obtained. To be added, by analysing the data which only including those based on navigable semicircle, it is possible to produce a standard typhoon which could result in setting-down of sea level.