• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.285-286
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• 2008

• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.54-59
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• 2011

Generally, the flow hunting is observed in almost all of the orifice meters but the intensity of the flow hunting is different at each metering system. In order to investigate the relations between pipe diameter and the flow instability or the flow hunting in a real metering system, a one-dimensional pipeline network model was built and analyzed for the examination of flow characteristics and relations to the flow hunting, changing diameters of the meter and the pipes before and after the meter. Finally, the effects of pressuredifference variation and flow hunting following to the variations of the diameters of the meter and the pipes before and after the meter were investigated and the relations were examined as well.

• Journal of Power System Engineering
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• v.2 no.3
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• pp.68-73
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• 1998

The propulsion diesel engine have been widely applied with a mechanical governor to control the truck speed for a long time. But it was recently very difficult for mechanical governor to control the speed of long stock and diesel engine of truck because of hunting by dead time between fuel injection and power output. This study is aimed to configure the modeling for performance simulation regarding to diesel truck operation which could be suppressed for hunting. The modeling have been made on the base of dynamic characteristic such as electronic governor, injection of fuel system and operating states of diesel engine truck. Real model system have been introduced for deciding reacting parameters and for the comparison of resulting performance in simulation. In results of simulation, we obtained items which diesel truck drives for suppressed hunting.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.98-103
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• 2006

The hunting is the natural characteristics of the railway wheelset which is originated from the contact between the conical type wheel profile and rail. The critical speed of rolling-stock is called when the hunting is occurred, and it is closely connected with vehicle stability. The parameters which influence the hunting motion are like wheel profile, primary spring property and wheelset dimension, etc. The studies for these parameters are reported diversely. In this study, we aim to analyze the influence of parameters on hunting with the change of wheel profile produced by wheel wear and material property produce by aging of primary spring. For this, we made a dynamic model for wheelset and vehicle. Using these models, we analyzed the critical speed with the variations of the parameters like as wheel profile and primary spring property and we show the results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.15-23
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• 2021

In most hacking attacks, hackers intrudes inside for a long period of time and attempts to communicate with the outside using a circumvent connection to achieve purpose. research in response to advanced and intelligent cyber threats has been mainly conducted with signature-based detection and blocking methods, but recently it has been extended to threat hunting methods. attacks from organized hacking groups are advanced persistent attacks over a long period of time, and bypass remote attacks account for the majority. however, even in the intrusion detection system using intelligent recognition technology, it only shows detection performance of the existing intrusion status. therefore, countermeasures against targeted bypass rwjqthrwkemote attacks still have limitations with existing detection methods and threat hunting methods. in this paper, to overcome theses limitations, we propose a model that can detect the targeted circumvent connection remote attack threat of an organized hacking group. this model designed a threat hunting process model that applied the method of verifying the origin IP of the remote circumvent connection, and verified the effectiveness by implementing the proposed method in actual defense information system environment.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1006-1010
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• 2010

This paper discusses the numerical study on the stability of the high-speed EMU by developing its lumped parameter model including the effect of the creepage. The 6, 10 and 14 degrees-of-freedom (DOF) lumper parameter dynamic models are developed and the critical hunting speeds calculated from each model via Matlab software are analyzed and compared. It is demonstrated that the critical hunting speeds decrease while the degrees-of-freedom increase. In addition, the parametric study is conducted to extract major design parameters to influence on the stability of the high-speed EMU.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.755-762
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• 2004

Dynamic analysis of the KTX can predict the dynamic motions in test drive. In this study an analytical model of the KTX is developed to find the critical speed. The numerical analysis for the nonlinear equation motions of 17 degrees of freedom shows the running stability and the critical speed due to the hunting motion of the KTX. Also, the vibration modes of the KTX are calculated using the ADAM/RAIL software, which show that the critical speed occurs for the yawing modes of the car body and the bogie. Finally, this paper shows that the critical speed of the KTX could be changed with the modifications of the design parameters of wheel conicity or wheel contact length.

• Journal of Korea Game Society
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• v.14 no.5
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• pp.127-136
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• 2014

NPC in game is an important factor to increase the fun of the game by cooperating with player or confrontation with player. NPC's behavior patterns in the previous games are limited. Also, there is not much difference in NPC's ability among the existing games because it's designed to FSM. Therefore, players who have matched with NPCs which have the characteristics may have difficulty to play. This paper is for improving the problem and production and evaluation of the game NPC behavior model based on wolves hunting model in real life. To achieve it, first, the research surveys and studies behavior states for wolves to capture prey in the real world. Secondly, it is implemented using the Unity3D engine. Third, this paper compares the implemented state transition probability to state transition probability in real world, state transition probability in general game. The comparison shows that the number of state transitions of NPCs increases, proportions of implemented NPC behavior patterns converges to probabilities of state transition in real-world. This means that the aggressive behavior pattern of NPC implemented is similar to the wolf hunting behavior pattern of the real world, and it can thereby provide more player experience.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.2
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• pp.262-268
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• 2019

Previous dynamic models of hysteresis motor use an extended induction machine equivalent circuit or somewhat different equivalent circuit with conventional one, which makes unsatisfiable results. In this paper, the hysteresis dynamic characteristics of the motor rotor are analyzed using the inverse Preisach model and the hysteresis motor equivalent circuit considering eddy current effect. The hysteresis loop for the rotor ring is analyzed under full-load voltage source static state. The calculated hysteresis loop is then approximated to an ellipse for simplicity of dynamic computation. The permeability and delay angle of the elliptic loop apply to the dynamic analysis model. As a result, it is possible to dynamically analyze the hysteresis motor according to the applied voltage and the rotor material. With this method, the motor speed, generated torque, load angle, rotor current as well as synchronous entry time, hunting effect can be calculated.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.1-13
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• 2021

The purpose of this research is to analyze how the wage level of new job seekers in the platform labor market affects the period on getting the first job. Recently, the platform gets attention as one of alternatives to solve the increase of unemployment rate. It is important to create quality jobs that we build up a trust between employers and employees in the platform. Previous studies showed that feedback from previous employers is important for solving the information asymmetry problem between those people. However, there is no feedback for new job seekers who have not get the first job. Therefore, we focus on the fact that wages are presented by job seekers rather than employers in the platform, and we will figure out that the low wages of new job seekers may affect the shortening of job-hunting period. For this reason, we use 3,704 job seekers of Freelancer.com. Survival analysis shows that low wages for new job seekers have a significant impact on shortening job-hunting period.