• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.163-170
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• 2002

The quality of a precision product, in general, relies on the accuracy and precision of its manufacturing and inspection process. In many cases, the level of precision in the manufacturing and inspection system is also dependent on the positioning capability of tool with respect to the work piece in the process. Recently the positioning accuracy level has reached to the level of submicron and long range of motion is required. For example, for 1 GDARM lithography, 20nm accuracy and 300mm stroke needs. This paper refers to the lithography stage especially to fine stage. In this study, for long stroke and high accuracy, the dual servo system is proposed. For the coarse actuator, LDM (Linear DC Motor) is used and for fine one VCM is used. In this study, we propose the new structure of VCM for the fine actuator. It is 3 axis precision positioning stage for an aligner system. After we perform the optimal design of the stage to obtain the maximum force, which is related to the acceleration of the stage to accomplish throughput of product. And we controlled this fine stage with TDC. So we obtained 50nm resolution. So later more works will be done to obtain better accuracy.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.79-90
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• 2003

Internal metering policy(IMP) is a control strategy to improve the quality of traffic flow within a network by avoiding queue spillback or intersection blockage. It is a more aggressive control strategy than the current control strategy employed in COSMOS. A preliminary study was made to incorporate the IMP logic within the COSMOS system to improve its' functionality at oversaturated conditions. From the study results, a set of guideline for real implementation was recommended : traffic conditions, detector configurations, and control procedures, etc. A simulation study was performed to evaluate the effectiveness of the proposed guidelines. It was shown that the occurrence of queue spillback was minimized. and overall network performance was also improved by applying IMP logic as compared to COSMOS control onl.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1950-1951
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• 2007

본 논문에서는 코일건의 설계시 자기차폐 효과에 따른 코일건 성능 향상 및 최적화에 대하여 연구하였다. 일반적인 솔레노이드 코일건과 솔레노이드 코일에 자기차폐시킨 코일건의 자기장 분포를 유한요소해석을 통해 비교함으로써 자기차폐를 한 코일건의 자속밀도와 투사체가 받는 힘이 향상됨을 알 수 있었다. 또한 자기차폐시킨 코일건을 동일 코일량에 대한 성능 최대화를 위해 솔레노이드 형상을 최적화하고, 그 모델을 실제 제작하여 성능을 검증하였다.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.69-77
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• 2005

The purposes of this study were to develop and introduce a novel intraoral appliance for bruxism composed of power switch and biofeedback device and further to examine inter- and intra-reliability of the appliance prior to clinical tests. The newly-developed appliance consisted of detection sensors, a central processing unit (CPU), a reactor and a storage unit and a displayer. Compact-sized, waterproof switches were selected as bruxism detection sensor and any sensor activation by clenching or grinding event was processed at the CPU and transmitted, by radio wave, to the reactor and storage unit and triggered auditory or vibratory signal, subsequently producing biofeedback to the patient with bruxism. The data on bruxing event in the storage unit can be displayed on the computer, making it possible analyzing frequency, duration and nature of bruxism. Cast models were obtained from ten volunteers with normal occlusion to evaluate reliability of the appliances. For inter-operator reliability on the intraoral appliances, each operator of the two fabricated the appliance for the same subject and compared the minimal contact forces provoking auditory biofeedback reaction in vertical, lateral and central directions. Intra-operator reliability was also investigated on the appliances made by a single operator at two separate times with an interval of two days. Conclusively, the newly-developed appliance is compact and safe to use in oral circumstance and easy to make. Furthermore, it had to be proven reliability excellent enough to apply in clinical settings. Thus, it is assumed that this appliance with the processor and the storage of data and auditory or vibratory biofeedback function is available and useful to analyze and control bruxism.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.4
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• pp.113-122
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• 2013

In this study, the traditional structure of the impact on the stability analysis. Korean traditional landscape architecture column space of stonework stable composition as the foundation of the fence for a long time been known to fall down and not maintained. The destination of research Ohgokmun Damyang Soswaewon fence which is in harmony with nature is one of the traditional structures that affect its shape without being kept so far came true. This includes our ancestral wisdom and that wisdom can guess guesswork. But I let the traditional reproduction incidence structures frequently. This deviation from the traditional method of construction application of shorthand stand. Thus, the subject of this study, the factors that do not fall down fences Ohgokmun solution is to indirectly gain the weak. In addition, epidemiological studies and the methods of calculation of the inferred physical examination, the results of the analysis were derived through the following. First, the internal factors of the fence Ohgokmun constituting the structural member and the coupling of the scheme. 1) based on stable ground. Greater role in the country rock The fact that the settlement will have no symptoms. 2) to minimize the friction caused by hydrological water to remove the two-pronged process through stone work building form and menu sustaining power in hydrology and flooding made against the bypass channel. 3) due to the load bearing capacity and durability to withstand the strength of the material and the construction of structures in the form of a dispersion of power between each individual to maximize the process of getting traction was applied. Second, external factors Ohgokmun fence the results obtained through the calculation of the dynamics of repair, is greatly affected by the wind and the water gate of the fence, but the action of the structural stability of the lack of power that hurt enough conclusion. In this study, the results of the structure of internal and external influence as well through the structure can be viewed as composed consisting. However, over the next follow-up in terms of climate and environmental factors due to the fact that the fall might.

• Journal of the Korean Geographical Society
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• v.38 no.6
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• pp.961-970
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• 2003

The 1972 United Nations Conference on the Human Environment sparked off actions aimed at protecting the ocean on all scales. Physical science was essentially in the foreground, and the ecological dimension remained in the background as well. During the following two decades, ocean uses increased and spread unexpectedly, and there was an urgent need for management patterns to deal with coastal areas, regional seas, and with the ocean as a whole. Meanwhile, mainly thanks to the Man and the Biosphere (MAB) programme, the ecological dimension of the environmental issue became more evident, while the concept of sustainable development was designed by the World Commission on Environment and Development (1987). As far as the ocean is concerned, by adopting Agenda 21, the 1992 Conference on Environment and Development (UNCED) could neither embrace a wholly ecology-oriented policy, nor adopt the concept of sustainable development in its whole extent. This circumstance encourages efforts to consider the ocean from an effective ecological perspective, and to explore how cultural and ecological systems have interacted. Hence the concept of diversity becomes an increasingly key factor.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.223-231
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• 2019

A continuum-based design sensitivity analysis(DSA) method is developed for electrostatic problems. To consider high order objective functions, we use 9-node finite element basis functions for analysis and DSA methods. As the design variables are parameterized with B-spline functions, smooth boundary variations are naturally obtained. To solve mesh entanglement problems during the optimization process, a mesh regularization scheme is employed. By minimizing the Dirichlet energy functional, mesh uniformity can be automatically achieved. In numerical examples for maximizing dielectrophoresis forces, the numerical results are compared with well-known electrode geometries and the obtained characteristics are discussed.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.230-240
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• 2020

To develop a virtual world-based immersive tutoring system, we would like to develop a simulation in the spatial aspect to maximize the diversity and realism of the situation. This implementation requires the modeling of virtual space as well as the knowledge and intelligent thinking functions of virtual humans. First, information structures are needed to simulate the hierarchical and multifaceted composition of space and the corresponding knowledge of virtual humans. Specifically, four structures for 2.5D spatial distribution expression, complex spatial relationship expression, object expression, and temporal and spatial representation of events are developed respectively. It then uses these expressed knowledge to develop the spatial thinking function of virtual humans needed to make spatial movement. In general, events have a chain effect on adjacent or connected objects through force, resulting in a variety of situations and reflected in the planning of the next action by the virtual humans involved. For this purpose, the development of events according to historical trends is recorded on the representation structure of time and space. It embodies typical events to demonstrate the feasibility of independent behavior in complex spaces among virtual people.