• KIEAE Journal
• /
• v.15 no.6
• /
• pp.69-80
• /
• 2015

Purpose: Since most simulation programs take the interface that lists up all the input variables representing all the functionalities, users must know where design variables of an Energy Conservation Measure (ECM) are located and also know what values are appropriate. This is why practitioner designers feel frustrated when they attempt to use simulation. The final objective of this study is to provide a building energy modeling guideline for practitioners in various fields such as architectural design and MEP. Method: As the first step of the modeling guideline, this study provides the Level of Detail (LOD) for simulation modeling of primary ECMs considering the design information available in each design phase. It is prepared by literature review, simulation functionality investigation, and field experts' survey. Result: The proposed simulation LOD offers a milestone at each design phases concerning what design variable and attributes need to be developed with how much of details in order to meet the project goal. Also each design team can set up a simulation usecase considering organizational characteristics based on the proposed LOD.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.3 s.180
• /
• pp.125-131
• /
• 2006

Recently air pollution has become an important issue. So, as tile number of vehicles increases, the noise pollution has become one of the most serious social issues nowadays. It is a muffler, which is one of the vehicle components. that has the hugest impact on the noise from the vehicle. And it also has a direct influence on the engine performance. So lately the research is proceeding on tile semi-active muffler which can control the back pressure variably by setting up the exhaust variable valve in the baffle to improve its internal structure. The inner parts of muffler which consist of a baffle, pipes and etc. appear to have the complicated turbulence phenomena by the pulsational wave of an unsteady state in the engine and by the structural characteristics of the inner parts. To analyze these phenomena, it is required to have an analysis of its constant quantity and quality. Therefore this study is to analyze with PIV measurement which can analyze the time and space variables, not with the point measurement method like former multi-point anemometer. It is to suggest proper design variables which need to make internal structure of the muffler improve though comparison between the passive type muffler and the semi-active muffler by fabricating a muffler which can be visualized.

• Computers and Concrete
• /
• v.9 no.6
• /
• pp.469-486
• /
• 2012

This paper presents Neuro-Fuzzy (NF) based empirical modelling of torsional strength of RC beams for the first time in literature. The proposed model is based on fuzzy rules. The experimental database used for NF modelling is collected from the literature consisting of 76 RC beam tests. The input variables in the developed rule based on NF model are cross-sectional area of beams, dimensions of closed stirrups, spacing of stirrups, cross-sectional area of one-leg of closed stirrup, yield strength of stirrup and longitudinal reinforcement, steel ratio of stirrups, steel ratio of longitudinal reinforcement and concrete compressive strength. According to the selected variables, the formulated NFs were trained by using 60 of the 76 sample beams. Then, the method was tested with the other 16 sample beams. The accuracy rates were found to be about 96% for total set. The performance of accuracy of proposed NF model is furthermore compared with existing design codes by using the same database and found to be by far more accurate. The use of NF provided an alternative way for estimating the torsional strength of RC beams. The outcomes of this study are quite satisfactory which may serve NF approach to be widely used in further applications in the field of reinforced concrete structures.

• Journal of Applied Reliability
• /
• v.15 no.2
• /
• pp.108-123
• /
• 2015

Test and Evaluation (T&E) have been verifying the level of it's technological skill and the needed operational status of the development weapons. If the overall spectrum of test and evaluation is fulfilled substantially in the production & deployment, the needed level of the weapon system will be enhanced and also the reliability status will become higher considerably. We can know currently these issues through the mass media and all kinds of the news regarding the defense industry and programs. And so this article have studied the method of enhancing reliability of the test and evaluation, the 6 variables were selected through the discussion of the professional group. The the test and evaluation group needs consistently the professional training systems. After DT&E, we have to the event to verify the technical level of the development systems. We have to take the high level of the kinds of the environmental test. Scientific methods like system engineering will be adapted in process of the test and evaluation. The number of suitable test prototype in the test and evaluation is analysed more systematically. And we need to establish the standardization of the test and evaluation. If 6 variables are well analysed and adapted in the working field, the reliability of the test and evaluation will be considerably, the defense industry will take the chance to develope the future-oriented.

• Steel and Composite Structures
• /
• v.22 no.5
• /
• pp.975-999
• /
• 2016

This work investigates a thermomechanical bending analysis of functionally graded sandwich plates by proposing a novel quasi-3D type higher order shear deformation theory (HSDT). The mathematical model introduces only 5 variables as the first order shear deformation theory (FSDT). Unlike the conventional HSDT, the present one presents a novel displacement field which includes undetermined integral variables. The mechanical properties of functionally graded layers of the plate are supposed to change in the thickness direction according to a power law distribution. The core layer is still homogeneous and made of an isotropic ceramic material. The governing equations for the thermomechanical bending investigation are obtained through the principle of virtual work and solved via Navier-type method. Interesting results are determined and compared with quasi-3D and 2D HSDTs. The influences of functionally graded material (FGM) layer thickness, power law index, layer thickness ratio, thickness ratio and aspect ratio on the deflections and stresses of functionally graded sandwich plates are discussed.

• The Journal of Industrial Distribution & Business
• /
• v.8 no.4
• /
• pp.15-21
• /
• 2017

Purpose - In this work, we examined the causal relationship between credit loans from households (CLH), loan collateralized with housing (LCH) and an interest of certificate of deposit (ICD) among others in South Korea. Furthermore, the optimal forecasts on the underlying model will be obtained and have the potential for applications in the economic field. Research design, data, and methodology - A total of 31 realizations sampled from the 4th quarter in 2008 to the 4th quarter in 2016 was chosen for this research. To achieve the purpose of this study, a regression model with correlated errors was exploited. Furthermore, goodness-of-fit measures was used as tools of optimal model-construction. Results - We found that by applying the regression model with errors component ARMA(1,5) to CLH, the steep and lasting rise can be expected over the next year, with moderate increase of LCH and ICD. Conclusions - Based on 2017-2018 forecasts for CLH, the precipitous and lasting increase can be expected over the next two years, with gradual rise of two major explanatory variables. By affording the assumption that the feedback among variables can exist, we can, in the future, consider more generalized models such as vector autoregressive model and structural equation model, to name a few.

• Steel and Composite Structures
• /
• v.32 no.3
• /
• pp.389-410
• /
• 2019

In this article, a simple quasi-3D shear deformation theory is employed for thermo-mechanical bending analysis of functionally graded material (FGM) sandwich plates. The displacement field is defined using only 5 variables as the first order shear deformation theory (FSDT). Unlike the other high order shear deformation theories (HSDTs), the present formulation considers a new kinematic which includes undetermined integral variables. The governing equations are determined based on the principle of virtual work and then they are solved via Navier method. Analytical solutions are proposed to provide the deflections and stresses of simply supported FGM sandwich structures. Comparative examples are presented to demonstrate the accuracy of the present theory. The effects of gradient index, geometrical parameters and thermal load on thermo-mechanical bending response of the FG sandwich plates are examined.

• Journal of the Korean Dietetic Association
• /
• v.25 no.1
• /
• pp.44-58
• /
• 2019

Predicting the number of meals in a foodservice organization is an important decision-making process that is essential for successful food production, such as reducing the amount of residue, preventing menu quality deterioration, and preventing rising costs. Compared to other demand forecasts, the menu of dietary personnel includes diverse menus, and various dietary supplements include a range of side dishes. In addition to the menus, diverse subjects for prediction are very difficult problems. Therefore, the purpose of this study was to establish a method for predicting the number of meals including predictive modeling and considering various factors in addition to menus which are actually used in the field. For this purpose, 63 variables in eight categories such as the daily available number of people for the meals, the number of people in the time series, daily menu details, weekdays or seasons, days before or after holidays, weather and temperature, holidays or year-end, and events were identified as decision variables. An ensemble model using six prediction models was then constructed to predict the number of meals. As a result, the prediction error rate was reduced from 10%~11% to approximately 6~7%, which was expected to reduce the residual amount by approximately 40%.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.2
• /
• pp.686-710
• /
• 2019

This work proposes a model to solve the problem of Network Coding over a one-session multicast network. The model is based on a system of restrictions that defines the packet flows received in the sink nodes as functions of the outgoing flows from the source node. A multicast network graph is used to derive a directed labeled line graph (DLLG). The successive powers of the DLLG adjacency matrix to the convergence in the null matrix permits the construction of the jump matrix Source-Sinks. In its reduced form, this shows the dependency of the incoming flows in the sink nodes as a function of the outgoing flows in the source node. The emerging packets for each outgoing link from the source node are marked with a tag that is a linear combination of variables that corresponds to powers of two. Restrictions are built based on the dependence of the outgoing and incoming flows and the packet tags as variables. The linear independence of the incoming flows to the sink nodes is mandatory. The method is novel because the solution is independent of the Galois field size where the packet contents are defined.

• Geomechanics and Engineering
• /
• v.24 no.2
• /
• pp.167-178
• /
• 2021

Spatial variability is an inherent uncertainty of soil properties. Current reliability analyses generally incorporate random field theory and Monte Carlo simulation (MCS) when dealing with spatial variability, in which the computational efficiency is a significant challenge. This paper proposes a KL-FORM algorithm to improve the computational efficiency. In the proposed KL-FORM, Karhunen-Loeve (KL) expansion is used for discretizing random fields, and first-order reliability method (FORM) is employed for reliability analysis. The KL expansion and FORM can be used in conjunction, through adopting independent standard normal variables in the discretization of KL expansion as the basic variables in the FORM. To illustrate the effectiveness of this KL-FORM, it is applied to a case study of a strip footing in spatially variable unsaturated soil under rainfall, in which the bearing capacity of the footing is computed by numerical simulation. This case study shows that the KL-FORM is accurate and efficient. The parametric analyses suggest that ignoring the spatial variability of the soil may lead to an underestimation of the reliability index of the footing.