• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.1
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• pp.43-56
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• 2013

Personal Rapid Transit(PRT), which is one of the next generation convergence transport technology, PRT system requires operation technology for controlling diverse vehicles and dealing with a variety of abnormal driving situations on a large scale trackway structures in expected operational area more efficiently and reliably. Before developing PRT control technology, it is essential that multiple testing procedures stepwise with building small scale test-tracks and develop real unmanned-vehicles. However, it is expected that the experiments demand huge amount of time and physical cost. Thus, simulation in virtual environment is efficient to develop wireless based control technology for multiple PRT vehicles prior to building real-test environment. In this paper, we propose a VR-based integrated simulator which physics engine is applied so that it enables simulation of front-wheel-steering PRT system rather than simple rail track system. The proposed simulator is also developed that it can reflect geographical features, infrastructures and network topology of expected driving region.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.7
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• pp.63-70
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• 2004

This paper describes the link layer and physical layer of the Serial ATA which is the next generation for parallel ATA specification that defines data transfer between PC and peripheral storage devices. The link layer consists of CRC generation/error detection, 8b/10b decoding/encoding, primitive generation/detection block. For the physical layer, it includes CDR(Cock Data Recovery), transmission PLL, serializer/de-serializer. It also includes generation and receipt of OOB(Out-Of-Band) signal, impedance calibration, squelch circuit and comma detection/generation. Additionally, this chip includes TCB(Test Control Block) and BIST(Built-In Selt Test) block to ease debugging and verification. It is fabricated with 0.18${\mu}{\textrm}{m}$ standard CMOS cell library. All the function of the link layer operate properly. For the physical layer, all the blocks operate properly but the data transfer is limited to the 1.28Gbps. This is doe to the affection or parasitic elements and is verified with SPICE simulation.

• Geomechanics and Engineering
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• v.6 no.4
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• pp.341-358
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• 2014

Uplift response of rectangular anchor plates has been investigated in physical model tests and numerical simulation using Plaxis. The behavior of rectangular plates during uplift test was studied by experimental data and finite element analyses in cohesionless soil. Validation of the analysis model was also carried out with 200 mm and 300 mm diameter of rectangular plates in sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 200 mm and 300 mm computed maximum displacements were excellent for rectangular anchor plates. Numerical analysis using rectangular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in dense and loose packing of cohesionless soil.

• Geomechanics and Engineering
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• v.6 no.4
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• pp.321-340
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• 2014

Uplift response of symmetrical circular anchor plates has been evaluated in physical model tests and numerical simulation using Plaxis. The behavior of circular anchor plates during uplift test was studied by experimental data and finite element analyses in loose sand. Validation of the analysis model was also carried out with 50 mm, 75 mm and 100 mm diameter of circular plates in loose sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 100 mm computed maximum displacements was excellent for circular anchor plates. Numerical analysis using circular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in the loose sand.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.99-109
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• 2008

This research focused on analyzing and comparing between the results of hydraulic physical modeling and the results of numerical modeling of continuous block system in river bank protection which is newly developed in-situ block system. To verify the hydraulic physical modeling and review the effectiveness, the numerical modeling was needed against the model test results for vegetation application or not. HEC-RAS model was for 1 dimensional numerical analysis and SMS was for 2 dimensional numerical analysis. The results of the two dimensional numerical simulation, under the condition of roughness coefficient calibration, show similar and rational consequence against the physical modeling. These satisfactory results show that the accomplished results of hydraulic modeling and the predicted results of numerical modeling corresponded reasonably each others.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.4
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• pp.95-103
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• 2018

PURPOSE: The present study was conducted to investigate the effects of functional electrical stimulation gait training with rhythmic auditory stimulation on balance and gait ability in stroke patients. METHODS: In this blinded randomized controlled study, 26 stroke patients were assigned to either experimental group (n=13) consisting of 30 min of gait training 5 days per week for 4 weeks while performing functional electrical stimulation gait training with rhythmic auditory simulation, or a control group (n=13) performing the same gait training program, also consisting of 30 minutes 5 days a week and lasting for 4 weeks, but without functional electrical stimulation and rhythmic auditory stimulation. At baseline and after the 4 week intervention, balance was measured using the timed up and go test (TUG). Gait velocity was measured using the 10-meter walk test (10 MWT) and gait ability was assessed using the functional gait assessment (FGA). RESULTS: After the intervention, the experimental group showed statistically significant differences in gait velocity and ability (10 MWT, FGA) (p<.05). Between-group differences were statistically significant in gait velocity and ability (10 MWT, FGA) (p<.05). CONCLUSION: The findings suggest that functional electrical stimulation gait training with a rhythmic auditory stimulation gait training program may help improve gait ability in stroke patients.

• Journal of Ocean Engineering and Technology
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• v.35 no.1
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• pp.75-81
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• 2021

Artificial Coral Reefs (ACRs) have been introduced to help solve coastal erosion problems, but their feasibility has not been assessed with field data. This study conducted a feasibility analysis of ACRs on their erosion mitigation effects by performing a case study of Cheonjin-Bongpo beach, South Korea. A numerical-physical combined analysis was carried out using a SWAN model simulation and physical model test with a scale of 1/25 based on field observations of Cheonjin-Bongpo beach. Both Dean's parameter and the surf-scaling parameter were applied to comparative analysis between the absence and presence conditions of the ACR. The results for this combined method indicate that ACR attenuates the wave height significantly (59~71%). Furthermore, ACR helps decrease the mass flux (~50%), undertow (~80%), and maximum wave set up (~61%). The decreases in Dean's parameter (~66%) and the surf-scaling parameter suggest that the wave properties changed from the dissipative type to the reflective type even under high wave conditions. Consequently, an ACR can enhance shoreline stability.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.409-416
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• 2005

Design analysis for underground spaces requires evaluating stability related to tunnel collapses. A failure mode is one of the critical factors in the conventional methods of stability analysis. Therefore identification of failure modes is essential in securing safe construction in the phase of design analysis, instrumentation planning and implementation of reinforcing measures. In this study failure modes at the tunnel heading in granular soils are investigated using physical model tests and numerical simulation for various tunnel depths and ground surface inclinations. Test results indicated that the effect of depth and inclination of ground surface on a failure mode are significant. It is identified that, with an incase in depth, failure modes become localized in a region close to the tunnel. It is also known that an increase in the inclination of ground surface results in inclined and wide failure modes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.11 s.254
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• pp.1057-1065
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• 2006

In order to figure out the physical meaning of 3-D angular flow index for in-cylinder bulk motion, CFD analysis for the swirl and tumble steady flow test rig were made using commercial package STAR-CD. Computer simulations and rig tests on some kinds of induced flow conditions were carried out. Finally, based on the comparison between the simulated results and measured results, the physical meaning of 3-D angular flow index $|\longrightarrow_{N_B}|$, $\beta$ composed of swirl and tumble coefficients measured by steady flow test rig was described.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.263-273
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• 2007

When a tunnel or an underground structure is excavated in deep geological environments, the failure process is affected and eventually dominated by stress-induced fractures growing preferentially parallel to the excavation boundary. This fracturing is generally referred to as brittle failure by spatting and slabbing. Continuum models with traditional failure criteria such as Hoek-Brown or Mohr-Coulomb criteria have not been successful in prediction of the extent and depth of brittle failure. Instead cohesion weakening and frictional strengthening (CWFS) model is known to predict brittle failure well. In this study, CWFS model was applied to predict the brittle failure around a circular opening observed in physical model experiments. To obtain the input parameters for CWFS model, damage-controlled tests were carried out. The predicted depth and extent of brittle failure using CWFS model were compared to the results of the physical model experiment and numerical simulation using traditional model.