• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.128-128
• /
• 2000

An antenna tracking technique, referred to as "step track", is commonly used in communication applications. In this paper, an algorithm to improve the step-tracking technique for satellite tracking is proposed. We suggest a method by which the antenna scans the azimuth, detects the satellite signal without the position information, and points quickly to the direction receiving the signal of peak level. After reaching the peak level, the step-track system maintains enough signal levels to receive satellite broadcasting normally. Performance of the Tracking Algorithm proposed in this paper are verified with simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.261-264
• /
• 1997

In case of high speed and high mobility multibody tracked vehicle, it is hard to develop the realtime simulation model for track tension control because of the hundreds of highly nonlinear equations. In order to design more trustworthy realtime simulator for track tension control, it is necessary to use off-line tracked vehicle model. In this study, a step by step procedure is presented to develop realtime simulation model based on off-line tracked vehicle model. Simulation results show that modified off-line multibody tracked vehicle model can be used for real time simulation to control the track tension.

• Wind and Structures
• /
• v.35 no.4
• /
• pp.269-285
• /
• 2022

The pressure-mitigating effects of a high-speed train passing through a tunnel with a partially reduced cross-section are investigated via the numerical approach. A compressible, three-dimensional RNG k-ε turbulence model and a hybrid mesh strategy are adopted to reproduce that event, which is validated by the moving model test. Three step-like tunnel forms and two additional transitions at the tunnel junction are proposed and their aerodynamic performance is compared and scrutinized with a constant cross-sectional tunnel as the benchmark. The results show that the tunnel step is unrelated to the pressure mitigation effects since the case of a double-step tunnel has no advantage in comparison to a single-step tunnel, but the excavated volume is an essential matter. The pressure peaks are reduced at different levels along with the increase of the excavated earth volume and the peaks are either fitted with power or logarithmic function relationships. In addition, the Arc and Oblique-transitions have very limited gaps, and their pressure curves are identical to each other, whereas the Rec-transition leads to relatively lower pressure peaks in C_Pmax, C_Pmin, and ΔC_P, with 5.2%, 4.0%, and 4.1% relieved compared with Oblique-transition. This study could provide guidance for the design of the novel railway tunnel.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.123-126
• /
• 2005

Recently many accidents have been occurred on track workers, these accidents have strong relationship with increase of train speed, electrification and multiple track portion. As a first step for the safety management, domestic and abroad track worker accidents data are analysed for the risk estimation of track worker. Analysis results shows that contact between track worker and train is the dormant reason. In order to reduce dormant reason fault trees are constructed in this study.

• Atmosphere
• /
• v.21 no.2
• /
• pp.209-220
• /
• 2011

A new consensus algorithm for the prediction of tropical cyclone track has been developed. Conventional consensus is a simple average of a few fixed models that showed the good performance in track prediction for the past few years. Meanwhile, the consensus in this study is a weighted average of a few models that may change for every individual forecast time. The models are selected as follows. The first step is to find the analogous past tropical cyclone tracks to the current track. The next step is to evaluate the model performances for those past tracks. Finally, we take the weighted average of the selected models. More weight is given to the higher performance model. This new algorithm has been named as DYTRAP (DYnamic data-base Typhoon tRAck Prediction) in the sense that the data base is used to find the analogous past tracks and the effective models for every individual track prediction case. DYTRAP has been applied to all 2009 tropical cyclone track prediction. The results outperforms those of all models as well as all the official forecasts of the typhoon centers. In order to prove the real usefulness of DYTRAP, it is necessary to apply the DYTRAP system to the real time prediction because the forecast in typhoon centers usually uses 6-hour or 12-hour-old model guidances.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.2
• /
• pp.481-487
• /
• 2020

In this study, finite element analysis was performed to evaluate the track irregularity of the existing track system on urban transit according to the large-scale excavation work that is constructed adjacent to the serviced line. Based on the numerical analysis, the effect of track irregularity generated during the step-by-step construction process was analytically derived, and the stability in terms of track deformation was evaluated through comparison with related standards. As the results, in the case of track irregularity items evaluated based on the relative displacement difference at a certain distance, such as alignment and vertical irregularity, it occurred most clearly at the location where deformation of the existing structure begins, such as the end point of adjacent excavation work. On the other hand, the overall vertical and horizontal displacement of the track was the largest deformation at the center of the construction section. The vulnerable position of the deformed side of the existing structure due to adjacent excavation is analytically proven that the both of the end point section and the center of the construction can be a vulnerable position in terms of track irregularity.

• Structural Engineering and Mechanics
• /
• v.54 no.5
• /
• pp.1017-1044
• /
• 2015

This study aimed to investigate the random vibration characteristic of train-slab track-bridge interaction system subjected to both track irregularities and earthquakes by use of pseudo-excitation method (PEM). Each vehicle subsystem was modeled by multibody dynamics. A three-dimensional rail-slab- girder-pier finite element model was created to simulate slab track and bridge subsystem. The equations of motion for the entire system were established based on the constraint condition of no jump between wheel and rail. The random load vectors of equations of motion were formulated by transforming track irregularities and seismic accelerations into a series of deterministic pseudo-excitations according to their respective power spectral density (PSD) functions by means of PEM. The time-dependent PSDs of random vibration responses of the system were obtained by step-by-step integration method, and the corresponding extreme values were estimated based on the first-passage failure criterion. As a case study, an ICE3 high-speed train passing a fifteen-span simply supported girder bridge simultaneously excited by track irregularities and earthquakes is presented. The evaluated extreme values and the PSD characteristic of the random vibration responses of bridge and train are analyzed, and the influences of train speed and track irregularities (without earthquakes) on the random vibration characteristic of bridge and train are discussed.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2107-2114
• /
• 2011

To carry out the evaluation of performance of railway product/system, 3 step verification process(design review-lab test-field test) should be done. In advanced countries, for the effective field test, test-only-oriented track have been constructed and used. In Korea, government announced "The construction plan of railroad test track" at 2009.06. This paper will summarize 'need of test track', 'technical meaning of test track', 'current status of foreign test track', 'fundamental plan and process strategy of Korea Railroad Test Track'. It is no need to say that the wisdom of all railroad related people is required for the successful construction and usage of Korea Railroad Test Track.

• Korean Journal of Adult Nursing
• /
• v.20 no.2
• /
• pp.219-230
• /
• 2008

Purpose: The purpose of this study was to discover the recovery process of those having had myocardial infarction. Methods: 15 participants with myocardial infarction were recruited by theoretical sampling methods. The data were retrieved through in depth interview, participant observation, and medical records of the patients. Collected data were analyzed through grounded theory approach of Strauss and Corbin(1998). Results: 63 concepts, 27 subcategories, and 11 categories were deduced from the open coding process. The recovery process of myocardial infarction showed to be a process of 'Controling healthy track', and chronological recovery process was a four-step process of recognizing disruption of healthy track, making efforts for controlling the disrupted healthy track, reconstructing the new healthy track, and adapting to the new healthy track phase. 'Controling healthy track' had three types of self-initiation, contention of reality, and fateful acceptance. Conclusion: The results provided basic information for nursing intervention strategies depending on 'Controling healthy track' process by each phase and different types.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.4
• /
• pp.676-683
• /
• 2011

In this paper, we propose a robust method which can detect and track a high-speed small approaching target in a cluttered environment for Korean Active Protection System. The proposed method uses a temporal and spatial filter, tracking filter to detect and track a single target in consecutive order. And it is comprised of a candidate target detection step, a prior target selection step and a target tracking. Field tests on real infrared image sequences show that the proposed method could stably track a high speed and small target in complex background and target occlusion.