• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.2
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• pp.82-94
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• 1988

The purpose of this study is to introduce the Double Punch test method which is an indirect testing method of tensile strength of concrete, and to compare with the tensile strength of concrete as determined by the split-cylinder test, a practical method for performing the Double Punch test to obtain the tensile strength of concrete is proposed and recommended for general use. In this study, the dimensions of cylindrical specimens used in the Double-Punch test were 15X30cm, 15X15cm, 10${\times}$(20cm, and 5${\times}$l0cm, and in the split-cylinder test were 15${\times}$(30cm, 15${\times}$(15cm, and 10${\times}$(20cm. And the diameters of loading punches used in the Double-Punch test were 1.5cm, 2.5cm, and 3.5 cm. The results obtained from tests are summarized as follows ; 1. In the split-cylinder test, the tensile strength of concrete by the linear elasticity theory is similar to that of plasticity theory. 2. Both split-cylinder test and Double-Punch test, tensile strength of concrete is increased with decreasing specimen size. This tendency is identical when the ratio of specimen diameter to height is 1: 2, but that tendency is quite different when the ratio is 1: 3. In the Double-Punch test, if specimen size is constant, by increasing the punch size, tensile strength of concrete is increased, too. 4. Using a 15 ${\times}$( 15 cm cylinder specimen and 3.5 cm diameter punch in the Double Punch test would give the most uniform and consistent result in tensile strength, and the result showed a gQod correlation with splitting tensile strength from 15 x 30cm specimen. 5. In order to obtain satisfactory results and to nuninuze variability, it is proposed that specimens of 15 cm in diameter and 15 cm in height with two 3.5 cm diameter punches should be used. It seems, therefore, reasonable tt) take f't=0.0024 P(kg / cm$^2$) as a working formula for computing the tensile strength in the Double Punch test for concrete.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.326-331
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• 2006

The Construction Management(CM) was adopted to the domestic construction industry 10 years ago, but it has suffered from so many problems. Therefore, this study intends to contribute to the development of the CM through suggesting the method which measures the service quality of the CM and the customer satisfaction. The most important thing of this method is SERVQUAL which is a multiple-item scale for measuring consumer perceptions of service quality. In order SERVQUAL which is widely used in the service industry to be applied to the CM field, this study modifies SERVQUAL partially and comes up with the detailed analysis way through the case research and then, finally considers the practical use and the problem of this method.

• Journal of Platform Technology
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• v.11 no.3
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• pp.68-75
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• 2023

This paper discusses methods for increasing the germination rate of barley seeds using low direct and alternating current power below 110V. The experimental apparatus used here is a parallel plate, with the bottom surface of the plate designed to be wider than the top surface to increase the size of the electrostatic field. As a result, three different magnitudes of electrostatic fields were created on the plates: the first ranging from 400V/cm to 600V/cm, the second from 600V/cm to 900V/cm, and the third from 2200V/cm to 2400V/cm. The finite difference method was applied to analyze the electrostatic field inside the parallel plate. The plant seeds used in the experiments were barley seeds produced domestically. The average germination rate of barley seeds using the presented electrostatic field in this paper was 57%, while it was 65% when using a microwave of 2.45GHz, compared to a control group with a result of 31%. An important difference between using the electrostatic field and the 2.45GHz microwave is the dry method and wet method. When applying these two methods to practical seed germination, it is necessary to consider the advantages and disadvantages of each experimental approach and choose the appropriate method accordingly.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.289-294
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• 2007

It has been 10 years Since December 1996 when CM method was institutionalized by Construction Industry Fundamental law. Even though construction market has been in stagnant of business activities till now, CM in Korea started to be activated by the introduction of CM method i.n public construction. In the end of 2005, the number of CM order's contract is 6.7 times , an amount of CM order's money is 9.2 times more than operation plan of CM system announced in 2001. Therefore, CM market has been dramatically growing. However, it is judged that the shortage of faith in CM project and necessity of CM method are not recognized and study on a owner who affects successful settlement of CM has not been performed. When considering those points, in introduction and practical use of CM, CM is suggested to the field which is necessary for a client through the task performance level research and analysis of a owner who act a important role to activate Construction Management. As result of studying pre-existing papers to i.nvestigate of owner's capability level, the task function of a client is classified into 10 types and a public opinion poll was performed based on the 10 types of function.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.96-104
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• 2019

Recently, projects are being actively promoted to develop a new residential district centered around the metropolitan area, or to redevelop the residential area that was established long ago as unplanned land development. In this residential area, the owner can directly construct the building, and the way the building owner builds the residential house is called the direct construction of the owner. If the owner has the construction management (CM) capability while conducting direct management of the owner, the direct construction can be carried out by the CM method. This type of construction is called Owner-CM delivery method. However, it is very rare for small-scale construction in Korea to be implemented by the Owner-CM method. This may be due to the lack of knowledge and experience about the CM of the owner. In this study, we investigated the actual cases of the scheduling for the residential houses of similar size which were built at the same time in the residential housing complex developed near the metropolitan area. The purpose of this study is to derive the success factors of the scheduling in the small-scale construction from the cases carried out by the Owner-CM method. These success factors of the scheduling can be used as meaningful reference for the owners who want to build their own house in the future.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.433-439
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• 2014

Beam quality is changed about magnetic field of bending magnet. Evaluation of beam quality using PDD(Percentage Depth Dose) at 10cm depth at recommendation of AAPM(America Academy of Pain Medicine). However this evaluation shows fragmentary element. Therefore this study is applied to three value, 10cm divided by 5cm depth PDD, 20cm divided by 10cm depth PDD, 30cm divided by 20cm depth PDD, at change the magnetic field. PDD is measured at magnetic field changed ${\pm}1%$, ${\pm}2%$ at 6MV(Mega Voltage), 10MV photon. The plan technique is 3 portal plan using Core-Plan at human pelvic phantom. Conventional and presented methods are compared at maximum and minimum dose. The presented method increased discernment of relieve the unequal distribution and energy area than conventional method. Henceforth, application of presented method will be considered. Development of energy measurement method and detector miniaturization will be needed about continuous study.

• Journal of radiological science and technology
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• v.44 no.5
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• pp.435-441
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• 2021

The purpose of this study was to evaluate the quality of images and to quantitatively measure and analyze the dose of scattered ray to the organs, which were highly sensitive to radiation according to the use of cylinder cone in mastoid process radiography. When the cylinder cone was not used, the SID was 100cm and the field size was 24 × 36 cm(864 cm²). When using the cylinder cone which was a circle, the SID was 70 cm, the radius was 10.5 cm and field size was 86.59 cm². As a result of the study, SNR of the image quality evaluation was measured to be 2.58 for Law method and 3.90 for Stenver's method when not using cylinder cone, and 2.87 for Law method and 14.67 for Stenver's method when using cylinder cone. CNR was measured to be 0.03 for Law method and 0.04 for Stenver's method when cylinder cone was not used, and 0.04 for Law method and 0.05 for Stenver's method when using cylinder cone. When the cylinder cone was not used, the scattered ray dose was measured to be 0.10 mGy in the right eyeball, 0.30 mGy in the left eyeball, 2.02 mGy in the parotid gland, and 0.29 mGy in the thyroid gland for Law method and to be 0.03 mGy in the right eyeball, 0.12 mGy in the left eyeball, 1.43 mGy in the parotid gland, and 0.09 mGy in the thyroid gland for Stenver's method. When the cylinder cone was used, the scattered ray dose was measured to be 0.05 mGy in the right eyeball, 0.03 mGy in the left eyeball and the parotid and thyroid gland were below the measurable values for Law method and all areas were below the measurable values for Stenver's method. This was found to be statistically significant(p<0.000).

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.41-52
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• 2004

Construction Management(CM) that is the business innovation and method of construction management is introducing and implying the needs to improve high cost and low productivity structure and cope with very variable changes of construction market in construction industry within the country. But, safety management system is a very insignificant thing under CM. Consquently, We had been needed for the improvement about what the problem was. Therefore, My study raised the problem to the system and management by making a comparative study of the feature of the management method and the content of the accomplishment of safety management by using the consideration of the case about a big field of construction work implying CM within the country and proposed the active method of safety management.

• Interaction and multiscale mechanics
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• v.5 no.2
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• pp.131-144
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• 2012

We study a radial basis function collocation method (RBFCM) to discretize a coupled nonlinear Schr$\ddot{o}$dinger equation (CNLSE) that governs a two dimensional rotating Bose-Einstein condensate (BEC) with an angular momentum rotation term. We exploit a RBFCM-continuation method (RBFCM-CM) to trace the solution curve of the CNLSE. We compare the performance of the RBFCM-CM with the FEM-CM. We observe that the RBFCM-CM is very robust in a coarse grid for resolving the ground state solution with many vortices when the angular momentum rotation is close to the limit. Numerical results demonstrate the efficiency and accuracy of the RBFCM-CM for computing the superfluid density of the ground level of the BEC.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.5
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• pp.3-11
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• 2004

The objective of this study is to develop water saving irrigation method using water balance model in order to save rural water. Daily water balance components such as irrigation water, drainage water, effective rainfall, ET, and infiltration were measured in paddy fields. Model simulations were performed for different outlet heights and ponding depths. The outlet heights and the ponding depths are 2 cm, 4 cm, 6 cm, 8 cm, and 10 cm, respectively. Based on the simulation very shallow ponding depth of 2 cm with 10 cm outlet height showed the largest effective rainfall ratio and the smallest irrigation amount. Until the introduction of laser leveling dozer and automatic inlet control devices, it would be desirable to adopt 4cm ponding depth because of difficulty of land leveling and frequency of farmer's field visit. The results of this study will be applied in the paddy farming and can improve water use efficiency.