• Journal of the Korean Data and Information Science Society
• /
• v.17 no.1
• /
• pp.31-39
• /
• 2006

In many cases, we frequently get a desired information based on the appropriate statistical analysis of collected data sets. Lots of statistical theory rely on the assumption of the normality of the data. In this paper, we compare the empirical power of some normality tests including sample entropy quantity. Monte carlo simulation is conducted for the calculation of empirical power of considered normality tests by varying sample sizes for various distributions.

• Proceeding of KASS Symposium
• /
• 2006.05a
• /
• pp.256-264
• /
• 2006

This paper describes the formulation of rectangular flat shell element that is modeled with the six degree of freedoms including a rotational degree of freedom. The rectangular finite element matrix with a rotational degree of freedom is developed using a beam stiffness matrix and compared with other methods. The outputs of the quantity of vertical deflection of cantilever beam show us the improving evidence of the Frame-Shell finite element matrix in a calculation of vertical deflections of cantilever beam.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.675-678
• /
• 2008

An abnormal storm by the typhoon of RUSA in 2002th year was broken out with tremendous flood demages and inundations on the basin of Chogangcheon located in the upper middle part of Guem river's upstream. This flood could not be engaged because it was so big that the stage engaging Songcheon station stuck to Songcheon bridge was destroyed by submerging. In this study the quantity of the flood was calculated by use of Manning's equation and suitable roughness coefficient was suggested.

• Transactions of the KSME C: Technology and Education
• /
• v.2 no.2
• /
• pp.105-111
• /
• 2014

Generally the lower part of the Earth's atmosphere, which is 20km above the ground, is called "air." The composition of this area is almost consistent consisting of nitrogen, oxygen, and other gases. Air density refers to the mass per unit volume of earth atmosphere. Though air is made of the mixed gases in a constant composition, the water vapor is one of the very changeable components. The density of moist air is lower than the dry one at the same temperature and pressure. As the density varies according to the pressure and temperature, this paper attempts to explore the main factors in the air quantity calculation by examining first the density calculation process according to the air property, and second the relation between the actual and standard air flow.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.5
• /
• pp.153-159
• /
• 2012

For the enhancement of civilization of a city, the standard landfill facility is needed for the efficient, and computerized management. In this paper, we proposed the waste volume calculation method using the point cloud of the surface of three dimensional object based on stereo camera measurement. This computes the quantity of waste volume for continuos monitoring. It helps not only to predict the evaluation factor of the usable age of a landfill. facility. Furthermore, it can be used for the basis of general algorithm of three dimensional object.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.1097-1108
• /
• 2017

Accurate calculation of the conduction and switching losses of a power electronic converter is required to achieve the efficiency of the converter. Such calculation is also useful for computing the junction temperature of the switches. A few models have been developed in the articles for calculating the switching energy losses during switching transitions for the given values of switched voltage and switched current. In this study, these models are comprehensively reviewed and investigated for the first time for ease of comparison among them. These models are used for calculating the average amount of switching power losses. However, some points and details should be considered in utilizing these models when switched current or switched voltage presents time-variant and alternative quantity. Therefore, an applicable technique is proposed in details to use these models under the above-mentioned conditions. A proper switching loss model and the presented technique are used to establish a new and fast method for obtaining the average switching power losses in any type of power electronic converters. The accuracy of the proposed method is evaluated by comprehensive simulation studies and experimental results.

• Journal of Applied Reliability
• /
• v.18 no.2
• /
• pp.143-152
• /
• 2018

Purpose: In this paper, we propose calculation methods of Maintenance Float (M/F). Results of each method are compared and verified by using commercial tool (OPUS Suite). As modern weapon systems become more expensive, we need to find the most economical and efficient method to achieve the target operational availability (Ao). Methods: Three kinds of methods (Considering the number of CSP, Applying the Poisson distribution, and Applying M&S Tool) are used to find the number of M/F. Three methods (Considering the number of CSP, Applying the Poisson distribution, and Applying M&S Tool) were used to estimate the required number of M/F. The analysis results were verified by SIMLOX. The cost of equipment calculated by each analysis method was compared and the cause of the difference was analyzed. Conclusion: Ao and cost must be considered to find the optimal number of M/F. In general, it costs more to increase availability. But the cost is not necessarily proportional to Ao. Therefore, it is better to compare the calculation method and determine the final MF quantity.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.6
• /
• pp.89-97
• /
• 2019

Recently, BIM has been actively introduced in construction projects. In particular, the introduction of BIM in cost estimating process is expected to improve the accuracy and efficiency of the cost estimate. However, the quantity calculation and BoQ documents preparation process still require manual work. Although the BIM model may support quantification process, it is still problematic that the level of detail of the model must be very detailed to meet the items in BoQ. To address this, it is necessary to analyse the LOD criteria and to analyze the extent to which quantity can be computed according to the level of detail in the BIM model. For the analysis of LOD-based work items, the work item grades were divided into A,B, and C. In this study, the ratio and cost of each item that can be calculated at the LOD level in the detailed design phase are reviewed for each type of work, and the method for improving the quantity calculation using BIM is proposed. In the LOD 300 stage(Detailed design stage), the largest number of items in the class B, the major improvement class, are window and glass work. In addition, the most expensive type of work was analyzed by reinforced concrete work. In the future, it is necessary to suggest appropriate improvement way for items with high item ratios and items with high cost ratios. The results of this study are expected to be used as a BIM-based cost estimation or as basic data for improving the current BoQ system.

• Fire Science and Engineering
• /
• v.24 no.3
• /
• pp.93-98
• /
• 2010

Even though the sprinkler system is a essential fire suppression system, the design engineers do not fully understand the concept of design area which sprinklers operate. They frequently made a mistake to form design area and calculate it. The shape of design area is a square or a rectangle which branch side line is a little longer than the cross main side. NFPA demands to lengthen the branch side to 1.2 times than the cross main side and FM demands 1.4 times. The longer the branch side at the same design area is, the bigger the water quantity and pressure is. At the results of hydraulic calculation of design areas, when the branch side is longer 1.2 times, the water quantity became 4.6% bigger than exact square and the pressure came to 4.67% bigger. When it is longer 1.4 times, the water quantity and the pressure are bigger 7.52%, 14.51%. Therefore, the sprinkler design engineers should follow the general rule of design area, exact square or rectangle which length along the branch line is a little longer than length along the cross main, to design more stable system.

• Journal of the Korea Concrete Institute
• /
• v.25 no.4
• /
• pp.365-370
• /
• 2013

In this study, contents of limestone in cement manufactured by six domestic plants for Portland cement were investigated in terms of the strength and its relation to the $CO_2$ emission due to limestone material and its physical properties in cement manufacturing process. the relationship among CaO content, compressive strength, and $CO_2$ emission was surveyed for the limestone quantity in decomposition reaction and the loss of limestone quantity contained in each cement. As a result of $CO_2$ emission calculation for unit cement, it was found that the $CO_2$ emission due to decomposition of limestone was occupied 67% of total emission quantity. Furthermore, there was a difference in $CO_2$ emission quantity depending on the cement manufacturing process management. Also, it was shown that fossil fuel usage and material loss had a major influence as main factors of $CO_2$ emission. An increase in the CaO content in cement resulted in an increase in the compressive strength. On the contrary, CaO content and compressive strength were reduced with the growth of loss quantity of limestone. It was verified that the material and process management were more effective than CaO yield in cement manufacturing for $CO_2$ emission with the growth of $CO_2$ emission quantity. Pozzolanic materials such as PFA and GGBS in concrete mix affected the price, $CO_2$ emission and development of strength of concrete.