• 한국경영과학회지
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• 제3권2호
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• pp.75-90
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• 1978

The objective of this paper is to demonstrate how System Dynamics Approach may be used to develop new ways of analyzing and projecting manpower requirements and resources. For this purpose, a System Dynamics Model is presented as an example. An examination of the model will show that a System Dynamics modeling approach is an innovative and useful tool for manpower policy analysis and planning. Second, with minor modifications, the model may be used for manpower policy analysis and planning for any skilled personnel in Korea. For example, a similar model nay be built for engineers to analyze the effects of alternative policies about engineering education, sur as the number of available places in the various institutions of training, scholarships and loans, and the duration of training. An engineer's model may also be used to make the projections of the supply and requirements of engineers in the future according to various alternative assumptions where each assumption represents a policy option.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1225-1227
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• 2004

The robotic shoe testing system that mechanically simulates human motion was proposed to overcome the problems associated with human subject tests. The objective of this study is to predict new motion trajectory for robot that will produce similar force and moment of particular human motion. In order to solve this problem, it is imperative to understand the dynamics of robot for shoe testing. The methodology using parameter estimation technique was proposed for this problem. Since the dynamics of robot is certainly different from that of human, it is necessary to adapt/modify the robot's trajectory for future analysis, which is currently under investigation.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.104-115
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• 1999

Cutting process, in general, is a closed-loop system consisting of structural dynamics and cutting dynamics, with the cutting forces and the relative displacements between tool and workpiece being the associated variables. There have been a number of works on modeling the cutting process of endmilling, most of which assumed that either one of the tool or workpiece be negligible in tis displacement. In this paper, the relative displacement between tool and workpiece was considered. The proposed model used experimental modal analysis for structural dynamics and an instantaneous uncut chip thickness model for cutting dynamics. Simulation of the model, a time varying cutting system, was performed using 4th order Runge-Kutta method. Subsequent simulation results were utilized to predict chatter over a variety of experiments in slotting operation, showing good agreement.

• 한국시스템다이내믹스연구
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• 제12권1호
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• pp.39-57
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• 2011

This paper is the result of simulation modeling concerning high-level radioactive waste repository(HLRWR) and people's mind for the facility. We describe a procedure of simulation modeling for resident's policy acceptance and perceived risk of HLRWR facility by using System Dynamics approach. To Complete some complicated works, we made the 20 pieces of stock-flow diagrams based on the causal loop diagram that is a blue print of whole variables and relations. The simulation outputs clearly show that cental government efforts to siting the HLRWR will be failed if nothing to give for the region's residents. On the contrary, a monetary incentive and a regional development program help to turn this gloomy situation into a desirable and acceptable condition dramatically. Government has to prepare the schemes considering the HLRWR acceptance and total supporting program including the cash and local development programs.

• 한국시스템다이내믹스연구
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• 제7권2호
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• pp.121-132
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• 2006

A container terminal should concentrate on efficient terminal operation in the long view and analyze an effect through introduction of hi-technology, automated equipments and intelligent information system, when they want to improve their reliability and competitive power in intense global competition. To do this, first this study finds out factors which affect competitive power of a container terminal, and relation between them. And then we used System Dynamics method to analyze an effect according to a value fluctuation of the factors in the long term.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.17-20
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• 2004

This research is focusing on industry dynamics of Korean Mobile Telecommunications Industry. Industry data from 1997 to April 2004 are used to analyze industry dynamics through variety use of case study and system dynamics modeling. As results, we found the importance of initial endowment, firm reputation, and handset subsidy strategy. Along with these player-based characteristics, government impacts on dynamics of competition are also investigated.

• Journal of Ecology and Environment
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• 제47권2호
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• pp.49-62
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• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

• 한국시스템다이내믹스연구
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• 제7권1호
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• pp.147-172
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• 2006

With the purpose of long-range planning toward local/regional sustainable development, it is desired to avoid unconditional industrialization and expansion and to build an eco-oriented development strategy considering site-specific characteristics of the environment. This paper thus aims at the elaboration of a system dynamics model of a locality/region so as to understand inherent dynamics of sustainable development and to assess the effectiveness of such an eco-oriented strategy. The model thus consists of several positive and negative feedback loops that accelerate or restrict local/regional economic growth within a system boundary incorporating the environment, economy, and society. The model is moreover applied to the assessment of the effectiveness of the development plan recently established in Damyang in JeollaNamdo, Korea. It is regarded in this case to be effective for population immigration and economic prosperity to give priority to restore the bamboo ecosystem and nourish a series of eco-friendly industries based on the bamboo items developed recently. It is also to be positive to sustainable development since it enables to maintain high quality of the environment from the outset of their development steps.

• 드라이브 ㆍ 컨트롤
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• 제16권1호
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• pp.36-44
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• 2019

Variable displacement swash plate piston pump analysis requires electric, hydraulics and dynamics which are similar to the one's incorporated in the complex fluid power and mechanical systems. The main variable capacity for the swash plate piston pumps, hydraulics or simple kinematic (swash plate degree, piston displacement) models are analyzed using AMESim, a multi-physics analysis program. AMESim is a multi-physics hydraulic analysis program that is considered good for the environment but not appropriate for environmental analysis for multibody dynamics. In this study, the analytical model of the swash plate type hydraulic piston pump variable capacity is modeled by combining the hydraulic part and the dynamic part through co-simulation of multibody dynamics program (Virtual.lab Motion) and multi-physics analysis (AMESim). This paper describes the whole modeling analysis method on the mechanical analysis of the multi-body dynamics program and how the hydraulic analysis in multi-physics analysis program works. This paper also presents a methodology for analyzing complex fluid power systems.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.465-472
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• 2008

An automotive windshield wiper system is modeled mainly for vibration analysis purpose. The model is composed of solid links, ideal joints, imperfect joints to simulate unavoidable manufacturing defects and bushings having stiffness, contact between a wiper blade and a wind screen glass, friction, a spring and an actuator. Main stream of wiper dynamics analysis has been obtaining a closed form of system of equations using Newton's or Lagrange's formula and doing a numerical simulation study to understand and predict the behavior of it. However, the modeling process is complex since a wiper system is of multibody and a contact problem occurs. When imperfection, such as dead zone of a joint and stiffness of a rubber bushing, should be included, the added complexity makes the modeling difficult. Since the imperfection is understood as main cause of problematic vibration, the dynamics model of a wiper system aiming vibration analysis should include such unavoidable manufacturing defects in the model. An open form of dynamic model of a automotive windshield wiper system with imperfect joints using a commercial software is obtained and a simulation analyssis is conducted for vibration reduction study.