• Title, Summary, Keyword: Dynamic Simulation

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Development of Simulation Technology Based on 3D Indoor Map for Analyzing Pedestrian Convenience (보행 편의성 분석을 위한 3차원 실내지도 기반의 시뮬레이션 기술 개발)

  • KIM, Byung-Ju;KANG, Byoung-Ju;YOU, So-Young;KWON, Jay-Hyoun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.20 no.3
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    • pp.67-79
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    • 2017
  • Increasing transportation dependence on the metro system has lead to the convenience of passengers becoming as important as the transportation capacity. In this study, a pedestrian simulator has been developed that can quantitatively assess the pedestrian environment in terms of attributes such as speed and distance. The simulator consists of modules designed for 3D indoor map authoring and algorithmic pedestrian modeling. Module functions for 3D indoor map authoring include 3D spatial modeling, network generation, and evaluation of obtained results. The pedestrian modeling algorithm executes functions such as conducting a path search, allocation of users, and evaluation of level of service (LOS). The primary objective behind developing the said functions is to apply and analyze various scenarios repeatedly, such as before and after the improvement of the pedestrian environment, and to integrate the spatial information database with the dynamic information database. Furthermore, to demonstrate the practical applicability of the proposed simulator in the future, a test-bed was constructed for a currently operational metro station and the quantitative index of the proposed improvement effect was calculated by analyzing the walking speed of pedestrians before and after the improvement of the passage. The possibility of database extension for further analysis has also been discussed in this study.

A Proposition on Applying Agent-based Model for Analyzing Logistics System (물류시스템 분석을 위한 행위자 기반 모형 적용에 대한 제언)

  • Kim, Jun-Hyuk
    • Journal of Korea Port Economic Association
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    • v.26 no.3
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    • pp.130-142
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    • 2010
  • The purpose of this paper is to propose applying agent-based model(ABM) for analyzing logistics system. Logistics problems become more complex and multi-faceted. As a result, the behavior of the system becomes more and more difficult to predict, we see the limitations of the traditional top-down approach in handling complexity. The ABM, that is the bottom-up approach, provides new modeling framework in system modeling. The ABM focuses on the interactions of subsystem or agents in whole system. Then the macroscopic picture of the whole system behavior is emerged as the microscopic interactions of agents are aggregated. The ABM assumes that each agent acts based on simple rules learned from dynamic interactions among other agents or its surrounding environment. The ABM has a great advantage in understanding emergent phenomenon that cannot be explained only through considering individual attributes. The ABM is an extremely useful method to analyze complex system such as logistics system. Therefore, the great research efforts and applications on the ABM to logistics system are encouraged in future.

A Study on the Effectiveness Analysis of Freeway Traffic Management Strategy Based on exTMS (exTMS기반의 고속도로 교통관리방안 효과분석에 관한 연구)

  • Sung, Ji-Na;So, Jae-Hyun;Oh, Young-Tae
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.5
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    • pp.38-47
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    • 2009
  • This paper aims to evaluate the freeway traffic management Strategy based on exTMS according to traffic situation of freeway. As freeway user's demands increase, we thus need future-oriented and optimized traffic management. So, through improving the existing system and introducing the advanced system, these systems evaluate for not only preparing the application in real world but also preliminary feasibility. To evaluate effects of the traffic management based on exTMS, in this study, shoulder LCS, advanced VMS(assumption in it is improving next-generation system which it can be offering diverse dynamic traffic information), Ramp-metering system are applicated in simulation. In addition, this study evaluates the effect when all proposed systems are applicated, and compare the individual effect of when independent system is applicated, through considering about traffic condition of V/C=0.5, V/C=0.8, V/C=1.2. The study results show that all assumed cases, the travel speed were improved according to the increasing V/C. Furthermore, the results of evaluated the individual system show that the shoulder LCS was found to be the largest effect, and the effect of VMS(detour rate is 11%) is larger than the other cases.

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Model Predictive Control for Distributed Storage Facilities and Sewer Network Systems via PSO (분산형 저류시설-하수관망 네트워크 시스템의 입자군집최적화 기반 모델 예측 제어)

  • Baek, Hyunwook;Ryu, Jaena;Kim, Tea-Hyoung;Oh, Jeill
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.6
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    • pp.722-728
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    • 2012
  • Urban sewer systems has a limitation of capacity of rainwater storage and problem of occurrence of untreated sewage, so adopting a storage facility for sewer flooding prevention and urban non-point pollution reduction has a big attention. The Korea Ministry of Environment has recently introduced a new concept of "multi-functional storage facility", which is crucial not only in preventive stormwater management but also in dealing with combined sewer overflow and sanitary sewer discharge, and also has been promoting its adoption. However, reserving a space for a single large-scale storage facility might be difficult especially in urban areas. Thus, decentralized construction of small- and midium-sized storage facilities and its operation have been introduced as an alternative way. In this paper, we propose a model predictive control scheme for an optimized operation of distributed storage facilities and sewer networks. To this aim, we first describe the mathematical model of each component of networks system which enables us to analyze its detailed dynamic behavior. Second, overflow locations and volumes will be predicted based on the developed network model with data on the external inflow occurred at specific locations of the network. MPC scheme based on the introduced particle swarm optimization technique then produces the optimized the gate setting for sewer network flow control, which minimizes sewer flooding and maximizes the potential storage capacity. Finally, the operational efficacy of the proposed control scheme is demonstrated by simulation study with virtual rainstorm event.

A Study on Robust and Precise Position Control of PMSM under Disturbance Variation (외란의 변화가 있는 PMSM의 강인하고 정밀한 위치 제어에 대한 연구)

  • Lee, Ik-Sun;Yeo, Won-Seok;Jung, Sung-Chul;Park, Keon-Ho;Ko, Jong-Sun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.11
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    • pp.1423-1433
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    • 2018
  • Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

Whiplash Injury Conditions of Rear-End Collisions at Low-Speed (저속 추돌사고에서 목 상해 조건에 대한 연구)

  • Kim, Myeongju;Yun, Ilsoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.18 no.2
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    • pp.58-76
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    • 2019
  • As the number of reported injuries has tended to increase over time, large hospitalization expenditure from excessive medical treatments and hospitalization, and insurance frauds associated with moral hazard in minor collisions have caused a global societal problem. Many occupants of rear-ended vehicles involved in rear-end collisions complain of whiplash injury, which is also known as neck injury, without any anatomical and radiological evidence. With only clinical symptoms, stating that a whiplash injury is a type of injury defined by the Abbreviated Injury Scale would be difficult. Therefore, this study focuses on minor rear-end collisions, where the rear-ender vehicle collides with the rear-ended vehicle at rest. The mathematics dynamic model is employed to simulate a total of 100 rear-end collision scenarios based on various weights and collision speeds and identify how the weights and speeds of both vehicles influence the risk of whiplash injury in occupants involved in minor rear-end collisions. The possibility of an injury is very high when the same-weight vehicles are involved in accidents at collision speeds of 15 km/h or higher. The possibilities are 36% and 84% with collision speeds of 15 km/h and 20 km/h, respectively, if weights are disregarded.

A Study on the Agent Based Infection Prediction Model Using Space Big Data -focusing on MERS-CoV incident in Seoul- (공간 빅데이터를 활용한 행위자 기반 전염병 확산 예측 모형 구축에 관한 연구 -서울특별시 메르스 사태를 중심으로-)

  • JEON, Sang-Eun;SHIN, Dong-Bin
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.2
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    • pp.94-106
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    • 2018
  • The epidemiological model is useful for creating simulation and associated preventive measures for disease spread, and provides a detailed understanding of the spread of disease space through contact with individuals. In this study, propose an agent-based spatial model(ABM) integrated with spatial big data to simulate the spread of MERS-CoV infections in real time as a result of the interaction between individuals in space. The model described direct contact between individuals and hospitals, taking into account three factors : population, time, and space. The dynamic relationship of the population was based on the MERS-CoV case in Seoul Metropolitan Government in 2015. The model was used to predict the occurrence of MERS, compare the actual spread of MERS with the results of this model by time series, and verify the validity of the model by applying various scenarios. Testing various preventive measures using the measures proposed to select a quarantine strategy in the event of MERS-CoV outbreaks is expected to play an important role in controlling the spread of MERS-CoV.

Strength and failure characteristics of the rock-coal combined body with single joint in coal

  • Yin, Da W.;Chen, Shao J.;Chen, Bing;Liu, Xing Q.;Ma, Hong F.
    • Geomechanics and Engineering
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    • v.15 no.5
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    • pp.1113-1124
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    • 2018
  • Geological dynamic hazards during deep coal mining are caused by the failure of a composite system consisting of the rock and coal layers, whereas the joint in coal affects the stability of the composite system. In this paper, the compression test simulations for the rock-coal combined body with single joint in coal were conducted using $PFC^{2D}$ software and especially the effects of joint length and joint angle on strength and failure characteristics in a rock-coal combined body were analyzed. The joint length and joint angle exhibit a deterioration effect on the strength and affect the failure modes. The deterioration effect of joint length of L on the strength can be neglected with a tiny variation at ${\alpha}$ of $0^{\circ}$ or $90^{\circ}$ between the loading direction and joint direction. While, the deterioration effect of L on strength are relatively large at ${\alpha}$ between $30^{\circ}$ and $60^{\circ}$. And the peak stress and peak strain decrease with the increase of L. Additionally, the deterioration effect of ${\alpha}$ on the strength becomes larger with the increase of L. With the increase of ${\alpha}$, the peak stress and peak strain first decrease and then increase, presenting "V-shaped" curves. And the peak stress and peak strain at ${\alpha}$ of $45^{\circ}$ are the smallest. Moreover, the failure mainly occurs within the coal and no apparent failure is observed for rock. At ${\alpha}$ between $30^{\circ}$ and $60^{\circ}$, the secondary shear cracks generated in or close to the joint tips, cause the structural instability failure of the combined body. Therefore, their failure models present as a shear failure along partial joint plane direction and partially cutting across the coal body or a shear failure along the joint plane direction. However, at ${\alpha}$ of $60^{\circ}$ and L of 10 mm, the "V-shaped" shear cracks cutting across the coal body cause its final failure. While crack nucleations at ${\alpha}$ of $0^{\circ}$ or $90^{\circ}$ are randomly distributed in the coal, the failure mode shows a V-shaped shear failure cutting across the coal body.

System Identification and Pitch Control of a Planing Hull Ship with a Controllable Stern Intercepter (능동제어가 가능한 선미 인터셉터가 부착된 활주선형 선박의 시스템 식별과 자세 제어에 관한 연구)

  • Choi, Hujae;Park, Jongyong;Kim, Dongjin;Kim, Sunyoung;Lee, Jooho;Ahn, Jinhyeong;Kim, Nakwan
    • Journal of the Society of Naval Architects of Korea
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    • v.55 no.5
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    • pp.401-414
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    • 2018
  • Planing hull type ships are often equipped with interceptor or trim tab to improve the excessive trim angle which leads to poor resistance and sea keeping performances. The purpose of this study is to design a controller to control the attitude of the ship by controllable stern interceptor and validate the effectiveness of the attitude control by the towing tank test. Embedded controller, servo motor and controllable stern interceptor system were equipped with planing hull type model ship. Prior to designing the control algorithm, a model test was performed to identify the system dynamic model of the planing hull type ship including the stern interceptor. The matrix components of model were optimized by Genetic Algorithm. Using the identified model, PID controller which is a classical controller and sliding mode controller which is a nonlinear robust controller were designed. Gain tuning of the controllers and running simulation was conducted before the towing tank test. Inserting the designed control algorithm into the embedded controller of the model ship, the effectiveness of the active control of the stern interceptor was validated by towing tank test. In still water test with small disturbance, the sliding mode controller showed better performance of canceling the disturbance and the steady-state control performance than the PID controller.

Optimal Wrist Design of Wrist-hollow Type 6-axis Articulated Robot using Genetic Algorithm (유전자 알고리즘을 이용한 손목 중공형 6축 수직다관절 로봇의 최적 손목 설계에 관한 연구)

  • Jo, Hyeon Min;Chung, Won Jee;Bae, Seung Min;Choi, Jong Kap;Kim, Dae Young;Ahn, Yeon Joo;Ahn, Hee Sung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.1
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    • pp.109-115
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    • 2019
  • In arc-welding applying to the present automobile part manufacturing process, a wrist-hollow type arc welding robot can shorten the welding cycle time, because feedability of a welding wire is not affected by a robot posture and thus facilitates high-quality arc welding, based on stable feeding with no entanglement. In this paper, we will propose the optimization of wrist design for a wrist-hollow type 6-Axis articulated robot. Specifically, we will perform the investigation on the optimized design of inner diameter of hollow arms (Axis 4 and Axis 6) and width of the upper arm by using the simulation of robot motion characteristics, using a Genetic Algorithm (i.e., GA). Our simulations are based on $SolidWorks^{(R)}$ for robot modeling, $MATLAB^{(R)}$ for GA optimization, and $RecurDyn^{(R)}$ for analyzing dynamic characteristics of a robot. Especially $RecurDyn^{(R)}$ is incorporated in the GA module of $MATLAB^{(R)}$ for the optimization process. The results of the simulations will be verified by using $RecurDyn^{(R)}$ to show that the driving torque of each axis of the writs-hollow 6-axis robot with the optimized wrist design should be smaller than the rated output torque of each joint servomotor. Our paper will be a guide for improving the wrist-hollow design by optimizing the wrist shape at a detail design stage when the driving torque of each joint for the wrist-hollow 6-axis robot (to being developed) is not matched with the servomotor specifications.