• KIPS Transactions on Software and Data Engineering
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• v.5 no.12
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• pp.653-662
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• 2016

This paper describes a test case generation algorithm for Simulink/Stateflow models based on the Rapidly exploring Random Tree (RRT) algorithm that has been successfully applied to path finding. An important factor influencing the performance of the RRT algorithm is the metric used for calculating the distance between the nodes in the RRT space. Since a test case for a Simulink/Stateflow (SL/SF) model is an input sequence to check a specific condition (called a test target in this paper) at a specific status of the model, it is necessary to drive the model to the status before checking the condition. A status maps to a node of the RRT. It is usually necessary to check various conditions at a specific status. For example, when the specific status represents an SL/SF model state from which multiple transitions are made, we must check multiple conditions to measure the transition coverage. We propose a unique distance calculation metric, based on the observation that the test targets are gathered around some specific status such as an SL/SF state, named key nodes in this paper. The proposed metric increases the probability that an RRT is extended from key nodes by imposing penalties to non-key nodes. A test case generation algorithm utilizing the proposed metric is proposed. Three models of Electrical Control Units (ECUs) embedded in a commercial vehicle are used for the performance evaluation. The performances are evaluated in terms of penalties and compared with those of the algorithm using a typical RRT algorithm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.105-112
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• 2009

In this paper, we investigated abnormal ESD failure on guard-rings in the smart power IC fabricated with $0.35{\mu}m$ Bipolar-CMOS-DMOS (BCD) technology. Initially, ESD failure occurred below 200 V in the Machine Model (MM) test due to current crowding in the parasitic diode associated with the guard-rings which are generally adopted to prevent latch-up in high voltage devices. Optical Beam Induced Resistance Charge (OBIRCH) and Scanning Electronic Microscope (SEM) were used to find the failure spot and 3-D TCAD was used to verify cause of failure. According to the simulation results, excessive current flows at the comer of the guard-ring isolated by Local Oxidation of Silicon (LOCOS) in the ESD event. Eventually, the ESD failure occurs at that comer of the guard-ring. The modified comer design of the guard-ring is proposed to resolve such ESD failure. The test chips designed by the proposed modification passed MM test over 200 V. Analyzing the test chips statistically, ESD immunity was increased over 20 % in MM mode test. In order to avoid such ESD failure, the automatic method to check the weak point in the guard-ring is also proposed by modifying the Design Rule Check (DRC) used in BCD technology. This DRC was used to check other similar products and 24 errors were found. After correcting the errors, the measured ESD level fulfilled the general industry specification such as HBM 2000 V and MM 200V.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.11-16
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• 2016

Fuel assembly's mechanical characterization test facility (FAMeCT) in KAERI was constructed with upgraded functional features such as increased loading capacity, underwater vibration testing and severe earthquake simulation for extended fuel design guideline. This facility is designed and developed to provide out-pile fuel data for accident analysis model and fuel licensing. Functional tests of FAMeCT were performed to confirm functionality, structural integrity, and validity of newly-built fuel assembly mechanical test facility. Test program includes signal check of data acquisition system, load delivering capacity using real-sized fuel assemblies and a standard loading cylindrical rigid specimen. Fuel assembly's lateral bending test was carried out up to 30 mm of pull-out displacement. Limit case axial compression loading test up to 33 kN was performed to check structural integrity of UCPS (Upper Core Plate Simulator) support frame. Test results show that all test equipment and measurement system have acceptable range of alignment, signal to noise ratio, load carrying capacity limit without loss of integrity. This paper introduces newly constructed fuel assembly's mechanical test facility and summarizes results of functional test for the mechanical test equipment and data acquisition system.

• Journal of Aerospace System Engineering
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• v.12 no.5
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• pp.32-39
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• 2018

In this paper, the calculation of the theoretical pressure transfer ratio due to the deformation of the thin-plate spring type check valve applied to the small piezoelectric-hydraulic pump was carried out. A thin-plate check valve is a flexible body that is deformed by an external force. The deformation of the check valve affects the rate at which the chamber pressure is transferred to the load pressure. The theoretical pressure transfer ratio for each model was calculated to compare the difference between the assumption that the thin-plate check valve is a rigid body and that of the flexible body model. The P-delta effect was considered for the calculation of the pressure transfer ratio of the flexible check valve model. In addition, a verification test for the calculated pressure transfer ratio obtained by considering the deformation of the flexible check valve model was carried out. The load pressure was measured by applying a thin-plate and ball-thin plate spring type check valves, respectively. The experimental pressure transfer ratio was calculated using the respective load pressure obtained from the experiments. The validity of the pressure transfer analysis of the check valve, taking into consideration the P-delta effect, was verified by comparing it with the theoretically calculated pressure transfer ratio.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.776-781
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• 2010

In the ship-handling simulator, it is important for a ship manoeuvring model to represent the dynamic characteristic of a ship and to be simple for reducing calculation time. Especially, even if principal dimensions of a ship are given in initial design stage, or manoeuvring test data are only given by model or real ship's trials, simulations are often needed to check the manoeuvrability of a ship. In this paper, a simple manoeuvring model based on turning test data of a ship is mathematically developed. And the simulation results are verified by comparing with turning test results of a real ship.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.212-212
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• 2000

This study was performed to construct a hot strip speed measuring system and check over whether the measured speed can be used for improving the mass flow of the head-end part of a hot strip in the 7-stand finishing mill. Because the mass flow in hot rolling mill affects the looper operation and the thickness and width control of a strip, accurate measurement of strip speed ie important. The measured speed was compared with the roll speeds of No. 6 and No.7 stand to check the performance of the system and analyzed to find how to apply the speed. As a result, it is shown that the accuracy of the system is enough, strip thickness error can be reduced by -275∼+200$\mu\textrm{m}$ using the measured speed and the existing FSU model has low accuracy for predicting forward slip rate. A neural network was developed to calculate forward slip rate instead of FSU model. The test result of the neural network shows that the neural network is more accurate than the FSU model.

• IE interfaces
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• v.6 no.1
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• pp.55-65
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• 1993

A nonstandard instrument used in the filed frequently becomes out-of-calibration due to environmental noise, misuse, aging, etc. A substantial amount of loss may result if such nonstandard instrument is used to check product quality and performance. Traditional periodic calibration at the calibration center is not capable of detecting out-of-calibration status while the instrument is in use, and therefore, statistical methods need to be developed to check the status of a nonstandard instrument in the field between calibrations. Developed in this paper is a unified measurement assurance model in which statistical calibration at the calibration center and measurement assurance test in the filed are combined. We developed statistical procedures to detect changes in precision and in the coefficients of the calibration equation. Futher, computational experiments are conducted to evaluate how the power of test varies with respect to the parameters involved. Based upon the computational results we suggest procedures for designing effective measurement assurance tests.

• Korean Journal of Construction Engineering and Management
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• v.23 no.2
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• pp.3-15
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• 2022

In this study, we develop a simulation model for Supply Chain Management (SCM) of modular construction based steel bridge. To this end, first, Factory Production/Site Construction system data for the steel bridge construction were collected, and supply chain, entities, resources, processes were defined based on the collected data. After that, a steel bridge supply chain simulation model was developed by creating data, flowchart, and animation modules using Arena software. Finally, verification and validation of the model were performed by using animation check, extreme condition check, average value test, Little' s law test, and actual case value test. As a result, the developed simulation model appropriately expressed the processes and characteristics of the steel bridge supply chain without any logical errors, and provided accurate performance evaluation values for the target system. In the future, we expect that the model will faithfully play a role as a performance evaluation platform in developing management techniques for optimally operating the steel bridge supply chain.

• Journal of Drive and Control
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• v.19 no.3
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• pp.39-46
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• 2022

In South Korea, to evaluate the rollover safety of domestic vehicles, the maximum slope angle of the vehicle is specified, which is verified by the rollover safety test of driving vehicles. However, the domestic rollover safety test is not suitable for buses, because the small amount of static stability factor (SSF) will invalidate the rollover experimental equation due to the high center of mass position of buses. To solve the above problems, a dynamic model of the bus is prepared with assumptions of mass and suspension spring properties. Subsequently, the maximum slope angle of the model was computed by using the simulation of multi-body dynamics, and the result was compared with actual test results to validate the dynamics model. Also, the rollover Fishhook (roll stability) test was conducted in the simulation for driving model. During the simulation, roll angle and roll rate were calculated to check if a rollover occurred. Through the rollover simulation of buses, the domestically regulated formula for rollover safety and the procedure of rollover test for driving vehicles are evaluated. The conclusion is that the present regulation of rollover test should be reconsidered for buses to ensure to get the valid results for rollover safety.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.187-192
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• 1995

Four types of experiments were performed to check the similitude of member behavior between prototype and 1/10 scale models:(1) Test of slender columns with P- effect, (2)Test of short columns with and without confinement steel, (3)Test of simple beams without stirrups, and (4)T-beam test. Based on the results of experiments, the conclusions were made as follows : (1) The P- effect of slender columns can be almost exactly represented by 1/10 acale model. (2)The effect of confinement on short columns by the hoop steel can also roughly simulated by 1/10 scale model. (3)The failure modes of simple beams models were the yielding of tension steel followed by large diagonal tension cracking+compressive concrete failure. (4)The behaviors of prototype and 1/10 scale model in T-beams appear very similar.