• Korean System Dynamics Review
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• v.16 no.1
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• pp.75-91
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• 2015

The price-volume in land by land categories is evaluated with dynamic approaches in the era of aging society This research tries to investigate in the respect of major factors such as real estate, macro-economics, and population that is simulated by land categories. The system dynamics approaches on price-volume in land are forecasted until 2020 using the data in the period of 2000-2014. In regard to methodologies, this research adopted system dynamics to evaluate the relationships between price-volume in land and aging society. The meaningful results have been found during the last over 10 year's analysis as the dynamic relations with major factors. Regarding land categories, this research tries to overcome former research limitations. As an implication from the price-volume in land, it confirmed that the multifaceted aspects show that system dynamics approach effectively simulated them by price-volume in land with the population of aging society.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.04a
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• pp.77-92
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• 1996

When an automatic course-keeping is concerned as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit (or telemotor unit) steering gear magnetic or gyro compass and ship dynamics. The consideration of irregular disturbances to ship dyanmics and a few non-linear mechanisms involved in the system inevitably or artificially are known to be very important in properly evaluating or analyzing the automatic steering system. In the present study the mathematical model of each element of an automatic steering system is derived which takes account of a fex non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. The calculation method of imposing irregular disturbances to ship dynamics is proposed where irregular disturbances implying irregular wave and the fluctuating component of wind. For he evaluation of automatic steering system of ships in the open seas an important term "performance index" is introduced from the viewpoint of energy saving which derived from the concept of energy loss on ship propulsion. Finally the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of linear and/or non-linear control constants of autopilot on propulsive energy loss are investigated to validate and clarify the present smulation technique.

• Journal of Wind Energy
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• v.2 no.2
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• pp.30-37
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• 2011

A floating wind turbine dynamic simulation program, WindHydro, is newly developed taking into account wind inflow and incident wave. WindHydro consists of 5 modules, HDFloat for hydrodynamics, HDProp for hydrodynamic property calculation, HDMoor for mooring dynamics, AeroDyn for aerodynamics, DAFUL for multi-body dynamics with nonlinear elasticity, and interface program that connects each calculation module. A turbulent wind and regular wave load case is simulated for the 5-MW OC3-Hywind with a spar bouy platform and catenary mooring lines. The results are compared with the results of the FAST(developed by NREL). As a result, the overall system responses from WindHydro and FAST agree well although some differences in the generator responses are observed.

• Journal of the Korean Regional Science Association
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• v.9 no.1
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• pp.79-99
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• 1993

This paper identifies the mechanisms governing the industrial location changes in Korea by focusing upon the emergence of the country's large conglomerate business organizations (chaebols). As the country has distinctive industrial organization, production systems, and government-business relations, this study tries to develop an ideal conceptual framework for the analysis of industrial location changes in Korea. It perceives the Korean economy as a system within which 'space-organizing', lage business organizations interact over time with government, smaller firms and multinational corporations at different geographical scales. The usefulness of the model is assessed using a case study of Korea's most representative chaebol, the Samsung Group. This study identifies chaebols as the dominant institutions in Korean society. Their growth and business strategies have been influenced by the Korean Government through its power to allocate capital resources. Regional dynamics of industry and labor, therfore, have been strongly influenced by changes in the location, industrial structure, and production system of chaebols. With econmic power concentrated within a few giant business groups and their major areas of operation restricted, unbalanced regional development has resulted. Dissatisfaction from residents in less-developed areas has pressured the Government to advise chaebols to disperse their production facilities. Most small and medium-sized firms are closely linked to large corporations through subcontracting. By forming hierarchical subcontracting. By forming hierarchical subcontracting systems, chaebols have indirectly exploited scattered, part-time, home-based, female and lower-paid laborers organized by subcontractors. Further, chaebols have expanded their business arena to encompass overseas locations in a bid to overcome the problem of a small domestic market, trade regulations and increased market, trade regulations and increased labor costs. Through their international business networks Korea's local and regional economies are integrated into the world economy. Indeed, the identification of the changing relationships of chaebols with both the Korean Government and smaller firms is the key to explaining the nations's spatial dyanmics of industry and labor.