• Nuclear Engineering and Technology
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• v.23 no.1
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• pp.30-40
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• 1991

For automatic power control of KMRR, a new method, Reactivity Constraint Method, is applied for time optimal control. This method limits the net reactivity to the amount that can be offset by instantaneous control rod action. The reactivity to be constrained for the constant reactor period should be obtained by the dynamic period equation. A new formulation of the dynamic period equation for 2-point kinetics model is presented. A methematical controller model was applied to the plant simulator, KMRSIM to test this control law. The performance test showed that reactivity constraint approach is also a reliable means for reactor power change control.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.5 s.149
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• pp.529-537
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• 2006

International Maritime Organization (IMO) is planning to include the Alternative Assessment of the Weather Criterion in the new Intact Stability (IS) Code to be revised. In this study, the procedure of the model test in the Interim Guidelines was reviewed by carrying out the model test and analyzing the test results. For this purpose, RO/RO passenger ship whose ratios of breadth to draft and the height of weight to draft were above 3.5 and above 0.6 respectively was selected as a test ship. Drifting test and motion test in regular waves were performed to estimate the hydrodynamic heeling lever and roll-back angle. Motion tests in waves were carried out in the three wave steepness conditions to measure roll-back angle and examine the feasibility of so called, the Three-step method. Using the test data, satisfaction of the Weather Criterion was assessed for the test ship by using the alternative method and compared with the current method.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.283-288
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• 2005

Test case prioritization methods schedule test cases for execution when we can not practically run all test cases for regression testing. We proposed a new prioritization method that is based on historical execution and mr detection data. And we conducted an experiment to compare the proposed method with existing Random and LRU methods using the fault age under the long run environment as criterion. The experiment shows several interesting results. First, our results show that they are complementary. Random method shows good performance for programs that have many error-detectable test cases and HED is more effective for the programs that can be detected by very small amount of test cases. But LRU is more effective for the programs that have relatively medium amount of error detectable test cases. Next, the performance of prioritization method is affected by the size of test suites. Two experiments that have different size of test suites show considerably different fault ages and performance order. And lastly, the $20\%$ of test cases shows considerably good performance compared to the execution result of the full test suite.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.96-103
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• 2008

In this study, we performed the biomechanical analysis of cervical plate systems by using a computer simulation based on finite element method to derive reliable model by analysis of design variables and fatigue behavior. To simulate the cervical spine movement in-vivo state by surgery, we modeled the cervical plate system which consisted of screws, rings, rivets, and plate and Ultra High Molecular Weight Polyethylene (UHMWPE) Block. The experiment of cervical plate system followed the ASTM F1717 standards that covered the materials and methods for the static and fatigue testing. The result of computer simulation is compared with experimented test. We expected this study is to derive reliable results by analysis of design variables and fatigue behavior for developing a new model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05c
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• pp.75-78
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• 2009

It was investigated fire resistance properties and mechanical properties of high strength concrete column using ECC(Engineered Cementitious Composites) permanent form by KS F 2257 Methods of fire resistance test for elements of building construction and compression test for application of precast concrete column method of high rise building in this study. As a test result, it was appeared that ECC permanent form is available as fire resistance method of high strength concrete and new precast concrete construction method for facilitating construction of high rise building.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.519-522
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• 2006

Accurate modeling of a dynamic system from experimental data is the bases for the model updating or heath monitoring of the system. Modal analysis or modal test is a routine process to get the modal parameters of a dynamic system. The modal parameters include the natural frequencies, damping ratios and mode shapes. This paper presents a new method that can derive the equations of motion for a dynamic system from the modal parameters obtained by the modal analysis or modal test. The present method based on the relation between the eigenvalues and eigenvectors of the state space equation derives the mass, damping and stiffness matrices of the system. The modeling of a cantilevered beam from modal parameters is an example to prove the efficiency and accuracy of the present method. Using the lateral displacements only, not the rotations, gives limited information for the system. The numerical verification up to now gives reasonable results and the verification with the test data is scheduled.

• Tribology and Lubricants
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• v.18 no.3
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• pp.187-193
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• 2002

The half-value breadth off-ray diffraction profile line is generally used for a factor in nondestructive hardness measuring method of steel. In this paper, the problem in using the half-value breadth for the hardness measuring method is evaluated in strain hardened steel. And new hardness measuring method using residual stress is proposed X-ray diffraction test after rolling contact fatigue test of ball bearing with inner race of various hardness are carried out to measure the distribution of residual stress and half-value breadth from surface. The result of this study shows that there is little correlation between half-value breadth and hardness in the higher strength region and in the region increasing the hardness by strain hardening. But the magnitude of residual stress on/under race after rolling contact fatigue test becomes clearly to be correlative with hardness. Thus, it is concluded that the hardness of strain hardened steel can be estimated by this relationship between residual stress and hardness.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.305-309
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• 2011

Reliability evaluation of One-Shot systems which fly at speed of Mach must evaluate as the result which leads a many firing test. But many firing test the fact that is impossible is actuality with problem of budget. Method of prediction leads consequently with alternative and will be able to present the alternative which evaluates. Prediction of One-Shot systems that how many did accumulate a many experience data according to the accuracy is decided, there is a possibility of seeing. One like shot our country and the method which is indirect leads from the environment where the test data is insufficient and only will not be able to set the direction of prediction, the present paper about such method describes 217 Plus where is a reliability prediction standard which is new the thing in standard.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.13-18
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• 2000

Nowadays, 60 percent of thermal power plants already have been operated over their own design life. These operations of old power plant over their design life have caused a fracture accident of degradation a loss of economic and human. Therefore, the new life assessment and prediction technology is necessary to improve the safety and reliability of high pressure and high temperature power plant facilities. In this paper, innovative electrochemical test method have been used and results have been compared to the conventional test. Finally, the electrochemical test is applied to the in-field HP turbine and a database is currently in progress for the development of the life assessment standard and procedure.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.1
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• pp.61-68
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• 2008

It is essential to analyze and classify the physical characteristics of weathered granite for engineering purposes. This paper is to suggest a physical method to determine the degree of weathering of weathered soils. A new classification method for determining the degree of weathering is suggested, based upon the results from laboratory tests including fall cone test. According to the proposed physical method using fall cone apparatus, the measured values of the samples from the same area show distinctive difference of weathering. The water content tends to increase with increasing the degree of weathering at the same penetration in fall cone test. And relationship between CWI and water content are expressed one equation in Hwaseong area and Ilsan area.