• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.213-220
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• 2011

Objective: The aim of this study was to investigate middle-aged drivers' driving performance and heart-rate as the behavior and physiological changes due to intersection types in left-turn situation. Background: In Korea, the drivers were aged 40~50s are most plentiful. In addition, the intersection traffic accidents are increasing every year. However, the researches for middle-aged drivers and intersection environments have been little. Method: In this study, three kinds of left-turning intersection types(T1, T2, T3) was used as the within-subject independent variables, three age groups(young, middle-aged, elderly) was used as the between-subject independent variables. Also, passing time, approaching velocity, speed and steering variations and heart-rate were used as dependent variables. Results: Overall, middle-aged drivers' driving behaviors were similar to those of the younger drivers. At the T2 intersection type, however, the approaching velocity of middle-aged drivers was similar to younger drivers, whereas the passing time of middle-aged drivers was similar to elderly drivers. Conclusion: These results could be interpreted that a transition driving behavior of middle-aged drivers in terms of age would be appeared on the T2 intersection type. Application: The results might help to understand the characteristics of driving behavior for middle-aged drivers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.5-14
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• 2002

Hemisphere shapes were machined for different tool paths and machining conditions with ball endmill cutters. It was also found out how feedrate affect the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Tool deflection, cutting forces and shape accuracy were measured according to the inclination position of the sculptured surface. As the decreasing of inclination position angle, the tool deflection was increased due to the decreased cutting speed when the cutting edge is approaching toward the center. Tool deflection when upward cutting IS obtained less than that of downward cutting and down-milling in upward cutting showed the least tool deflection for the sculptured surface. For down-milling, the cutting resistance of the side wall direction is larger than that of feed direction. It was found that the tool deflection is getting better as tool path is going to far from the center for convex surface.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.221-224
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• 1996

Since impact phenomenon is highly nonlinear, the analysis and control of the contact motion has been a challenging subject. Various researches have been carried out mostly for the contact of a rigid robotic manipulator with a stiff and elastic environment. This paper is motivated by a new contact task: the in-circuit test of a printed circuit board. In this process, high speed contact occurs between a rigid probing manipulator and a plastically deformable work environment. A new dynamic model of the impact controlled probing task has been proposed, considering contact with the plastically deformable object. Approaching velocity conditions to avoid an excess of the allowable penetration depth and control the generated impact force properly are derived from the proposed model. The results of the simulation studies are made for various probing conditions and show the validity of the proposed model.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.581-582
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• 2008

This paper describes novel bootstrapped CMOS differential logic family operating at near-Vth supply voltage. The proposed logic family provides improved switching speed by utilizing voltage bootstrapping for the supply voltage approaching device thresholds. The circuit is configured as differential structure having single bootstrapping capacitor, minimizing area overhead and providing complete logic composition capability. A 64-bit adder designed using the proposed technique in a 0.18um CMOS process provides up to 79% improvement in terms of power-delay product as compared to the conventional adder designed with DCVS.

• Journal of the korean Society of Automotive Engineers
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• v.4 no.2
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• pp.69-78
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• 1982

The purpose of this study is to investigate the flame propagation phenomenon in the combustion chamber of spark-ignition gasoline engine for the idling condition. by means of four ion probes located through the cylinder head, the time intervals for the flame to arrive at the respective probes are read on th visicorder char. As results, the flame is considered to initiate after some ignition delay and to propagate through the central space of combustion chamber with rather constant speed on the order of 25m/sec, and thereafter to be slowed down approaching the wall. Additionally, the retardation of flame in the wall boundary layer could be inferred. The maximum pressure is developed when the flame nearly touches the wall diagonal to the spark plug. And some features of flame propagation are elucidate.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.183-190
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• 2017

PURPOSES : The objective of this study is to establish the traffic volume-based warrants of right-turn lanes at unsignalized intersections and to introduce a risk probability methodology based on the warrants. METHODS : In this study, a risk probability of a potential rear-end collision is applied between a right-turn vehicle and the immediately following through vehicle. Using the shifted negative exponential model and the compound probability theorem, the risk probability can be expressed as the function of directional volumes and the percentage of right-turns for a two-lane and four-lane highway, respectively. RESULTS : Based on the risk probablity, guidelines for installing right-turn lanes on two-lane and four-lane highways were developed. The risk probability also showed rationality by comparing with right-turn same-direction conflicts observed in-situ. CONCLUSIONS : The results of our study define the total approaching volumes to encourage a right-turn lane as a function of operating speed, percentage of right-turn, and number of lanes.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.205-210
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• 2004

The interaction of disk galaxies with intergalactic winds has been invoked as a possible mechanism of the generation of galactic warps. Here we discuss conditions under which intergalactic flows can be relevant for warping field galaxies. Constraints include the heating of the outer disk, the level of asymmetry in the vertical distribution of the volume gas density, the angular frequency of the warp, the symmetry of galactic warps amplitude between the approaching and receding sides of the galaxy, and the speed of the intergalactic flow whether subsonic or supersonic. These constraints are discussed in this paper in reference to the proposal of Lopez-Corredoira et al. that warps can be a natural consequence of accretion flows onto the disk.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.2
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• pp.87-93
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• 2012

In this paper, a formation guidance method for UAVs (Unmanned Aerial Vehicles) to simulate the formation flight of birds proposed. The proposed method solves all issues of approaching for formation, formation keeping, and scarce chance to be collided with each UAV during formation process. Also, we design the feedforward controller to compensate the change of speed and heading for maneuvering of the leader UAV and the feedback controller to consider the response lag of the system. The stability and performance of the proposed controller is verified via numerical simulations of the full 6-Dof model of UAV.

• International Journal of Railway
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• v.3 no.3
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• pp.106-112
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• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• Journal of Navigation and Port Research
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• v.32 no.4
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• pp.271-277
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• 2008

When performing steering by an autopilot (automatic steering gear), a sensitivity adjustment is mainly determined by P value and D value. These values differ in the optimal combination by model of ship and external forces. This research was carried out simulation case studies and examined movement of Pure Car Carrier, which easily received ship by wind pressure influence in low speed We investigated the relation of horizontal migration(transfer) of ship's body and P-D value. Based on it, four parameters of P-D at approaching berth could be suggested Hence there were suggestions of parameters; Distance to maximum lee point, Time to maximum lee point, Time to return to original course and Time to 300th second. The correlation of these parameters and P-D value were also considered. As a result, we think that this index, like formulated P-D, leads to an easy and safe navigation by utilizing these indices.