• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.7
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• pp.561-568
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• 2008

The quality of the automatic transmission shift for a wheel loader has been generally evaluated by driver's perception. However the subjective evaluation of the drivers is not always directly related to the shift quality. It is necessary to set up the method for an objective assessment of the shift quality. In this paper, a quantitative assessment method has been developed for the shift quality of the automatic transmission in a wheel loader. The indices for the evaluation were selected through the various tests like the acceleration and the turbine rpm as well as the subjective evaluation of the driver, and were validated by the correlation between subjective and objective assessments using a psychophysical power law. Based on this method, the shift quality of a wheel loader has been evaluated quantitatively under various shift conditions.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.117-124
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• 2002

The lightness of components required in automobile and machinery industry is requiring high strength of components. In particular, manufacturing process and new materials development for solving the fatigue fracture problem attendant upon high strength of suspension of automobile are actively advanced. In this paper, the effect of compressive residual stress of spring steel(JISG SUP-9) by shot-peening on fatigue crack growth characteristics in high temperatures($100^{\circ}C,\;150^{\circ}C,\;180^{\circ}C$) was investigated with considering fracture mechanics. So, we can obtain followings. (1) Compressive residual stress is decreased in high temperature, that is, with increasing temperature. (2) The effect of compressive residual stress on fatigue crack growth behavior in high temperature is increased below ${\Delta}K=17{\sim}19MPa\sqrt{m}$. The fatigue crack growth rate is increased with increasing temperature. The fatigue life is decreased with increasing temperature. (3) The dependence of temperature and compressive residual stress on the parameters C and m in Paris' law formed the formulas such as equations (3),(4),(5),(6),(7),(8),(9),(10). (4) It was investigated by SEM that the constraint of compress residual stress for plastic zone of fatigue crack tip was decreased in high temperature as compared with room temperature.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.2
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• pp.59-65
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• 2017

When an anchor is dropped into the sea, there exists a danger of collision on the pipeline and subsea cables in the seabed. This collision could cause huge environmental disasters and serious economic losses. In order to secure the safety of subsea structures such as pipelines and subsea cables from the external impact, it is necessary to estimate the exact external force through the anchor's terminal velocity on the water. FLUENT, a computational fluid dynamic program, was used to acquire the terminal velocity and drag coefficient computation. A half-symmetry condition was used in order to reduce the computational time and a moving deforming mesh technique also adapted to present hydrostatic pressure. The results were examined with the equation based on Newton's Second Law to check the error rate. In this study, three example cases were calculated by stockless anchors of 5.25 ton, 10.5 ton, and 15.4 ton, and for the onshore experiment dropped height was back calculated with the anchor's terminal velocity in the water.

• The KSFM Journal of Fluid Machinery
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• v.8 no.3 s.30
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• pp.26-32
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• 2005

One of noticeable features in the cross flow fan is that a working fluid passes through impeller blade twice without distinction between the inlet and exit angles. Also, it does produce higher circumferential velocity than other types of blade at the same flow rate in accordance with the application of the forward curved shape. However, a design theory for the cross-flow fall has not yet been formed owing to an eccentric vortex, which is the remarkable characteristics, occurred in a cross-flow fan. Furthermore, the eccentric vortex, which is difficult to control the size and position, is the important cause of performance decrease. In this study, experiments we carried out to estimate the similarity of the cross-flow fan with various scales and rotational velocity changes. Pressure coefficients to flow coefficients with various scales of the cross-flow fan are plotted to the application of the general similarity law of the turbomachinery in the cross-flow fan with Archimedes spiral, which is the important factor having an effect on it.

• Journal of the Korean housing association
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• v.16 no.3
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• pp.27-35
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• 2005

The purpose of this study is to minimize physical obstacles for handicapped students in university dormitories. To carry out this study, we have surveyed 10 Universities in Korea. First we have studied the law and the theory of architectural planning and design guides those are related with handicapped people. And it was surveyed the existing state of the dormitories facilities and made a checklist. And the satisfaction about the facilities was questioned to the handicapped students who used those buildings. It is concluded that most of the universities which we have surveyed were equipped with good facilities for the general students but don't have regards for handicapped people at that time. As the result of the rate of the satisfaction, they are satisfied those facilities generally. As you can see the result of this research, the facilities in University are not very good for handicapped people in many points. So that kind of many facilities must be taken into consideration for handicapped people in the stage of architectural programming in the process of designing the dormitory building.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.175-181
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• 2015

In this study, a lithium polymer battery (LiPB) is simply expressed by a primary RC equivalent model. The PI state observer is designed in Matlab/Simulink. The non-linear relationship with the OCV-SOC is represented to be linearized with 0.1 pu intervals by using battery parameters obtained by constant-current pulse discharge. A state equation is configured based on battery parameters. The state equation, which applied Peukert's law, can estimate SOC more accurately. SOC estimation capability was analyzed by utilizing reduced Federal Test Procedure (FTP-72) current profile and using a bi-directional DC-DC converter at temperature ($25^{\circ}C$). The PI state observer, which is designed in this study, indicated a SOC estimation error rate of ${\pm}2%$ in any of the initial SOC states. The PI state observer confirms a strong SOC estimation performance despite disturbances, such as modeling errors and noise.

• The KIPS Transactions:PartA
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• v.13A no.1 s.98
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• pp.1-10
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• 2006

For efficient searching in unstructured peer-to-peer systems, random walk was proposed and several replication methods have been studied to compensate for the random walk's low query success rate. This paper proposes an efficient replication scheme that improves the accuracy and speed of queries and reduces the cost by minimizing the number of replicas and by utilizing caches. In this scheme, hub nodes store only content's caches, and one of their neighbors stores the replica. By determining hubs with only limited and local information, we can adaptively generate caches and replicas in dynamic peer-to-peer networks.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.311-325
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• 2011

The juvenile delinquency starts from trivial misconduct and reoccurs with the second offense. It is necessary the active plan to reduce the juvenile delinquency. The most important thing in processing the case of law breaking juveniles is to focus on the guidance process rather than punishment process in order encourage them to come back to society as normal members. In this process, I propose the specialist activation, the appropriate confrontation for the first criminals, the necessity for parents education, the mentor's activation, the program development to reduce the juvenile delinquency's second offense rate.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.321-326
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• 2006

The danger of self-ignition of single base propellants will increase with time. Therefore, a good prediction of the safe storage time is very important In order to determine the remaining shelf1ife of the propellants, the content of stabilizer is determined. The propellants stored under normal storage conditions about 10 to 18 years were investigated and accelerated aging test was carried out by storing propellant sample at higher temperature. Finally, we analyzed the results by various methods in order to show the best way to predict the realistic shelflife. The safe storage life of the propellants will be 24 years, at least 15 years. In case of applying Arrhenius's law, using the reaction rate constant at $28^{\circ}C$ to $30^{\circ}C$ to predict the shelflife by accelerated aging test is reasonable for a good prediction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.2
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• pp.7-15
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• 1986

In order to investigate the performance for the mackerel purse seine of one boat purse seiner using in the sea area of Cheju Island, a model net is made of the scale of 1/400 of its full scale, and model test on the shape of net and the tension of purse line is carried out in the stagnant water channel of the circulating water tank. Designing and testing for the model net are based on the Tauti's law. The obtained results are as follows; 1. The sinking rate of net is maximized the value of 6.40 m/min from 5 to 10 minutes after shooting net, and the mean value is 6.13 m/min. 2. The enclosed area formed with the float line after pursing operation is 76-84% of the area which is formed immediately after the shooting operation. At that time, purse seine is pulled inward the circle of surrounding net about 26.5% of the diameter. 3. In operating, when longitudinal section area of the central part of the net is maximized, the split area of both the wing-ends is 31-32% of the former. 4. When the time for the completing of pursing is 20 minutes, the maximum tension of the purse line is about 10.2 tons.