• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.404-408
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• 2005

Having flexibility in a manipulator will degrade trajectory tracking control and manipulator tip positioning. In practice, however, constraints imposed by various operating requirements, will render the presence of such flexibility unavoidable. The dynamic analysis of the flexible manipulator is essential in designing proper control systems. A flexible manipulator consists of infinite number of elastic modes and the modes are usually coupled to each other. For the practicality, however, it is usually assumed that the flexible system consists of finite number of elastic modes and the modes are decoupled. These assumptions result in a linear and decoupled mathematical model of the flexible manipulator and simplify the analysis of the dynamic behavior and the design of the control system. The decoupling and linearization of the flexible link, however, has been assumed without in depth analysis. This paper focuses on the analysis of the significance of the non-linear coupling factors.

• 한국정밀공학회지
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• 제14권1호
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• pp.205-213
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• 1997

In this study, dynamic analysis of a passenger car is carried out to analyze ride quality over a random road profile. The front suspension of the car is a MacPherson strut type and the rear suspension is a multi- link type. The following five different models are constructed and compared to see the effects of engine vibration and chassis flexibility in the ride quality. (1) one rigid chassis model, (2) a rigid chassis and rigid engine model, (3) a rigid engine and flexible chassis model with one vibration mode, (4) one flexible chassis model with six engine vibration modes and one chassis vibration mode, (5) one flexible chassis model with seven vibration modes and four static correction modes. The result shows that engine vibration modes and the first bending mode of the chassis are important in the ride quality.

• Ocean Systems Engineering
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• 제14권1호
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• pp.1-16
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• 2024

This paper investigates the impact of local joint flexibility (LJF) on the fatigue life of jacket-type offshore platforms. Four sample platforms with varying geometric properties are modeled and analyzed using the Opensees software. The analysis considers the LJF of tubular joints through the equivalent element and flexible link approaches, and the results are compared to rigid modeling. Initially, modal analysis is conducted to examine the influence of LJF on the frequency content of the structure. Subsequently, fatigue analysis is performed to evaluate the fatigue life of the joints. The comparison of fatigue life reveals that incorporating LJF leads to reduced fatigue damage and a significant increase in the longevity of the joints in the studied platforms. Moreover, as the platform height increases, the effect of LJF on fatigue damage becomes more pronounced. In conclusion, considering LJF in fatigue analysis provides more accurate results compared to conventional methods. Therefore, it is essential to incorporate the effects of LJF in the analysis and design of offshore jacket platforms to ensure their structural integrity and longevity.

• 지식경영연구
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• 제23권4호
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• pp.159-175
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• 2022

창의성이 조직의 성장과 발전에 중요하다는 점에서, 많은 기업들이 조직원의 창의성을 높이기 위한 방안들을 모색하고 있다. Dual pathway to creativity model 에 관련된 기존 연구에 따르면, 창의성은 두 가지 경로(인지적 유연성 혹은 인지적 지속성)를 통해 향상된다고 알려져 있다. 그러나, 이 두 가지 경로가 어떻게 활성화 되는지 이해하는데 있어서 조직원의 개인적 특질이 고려되어야 함에도 불구하고, 유연성과 지속성 중 어느 경로가 특정 성격에 더 효과적 인지에 대해서는 거의 논의된 바가 없다. 본 논문에서는, 애착 이론에 근거하여, 개인이 가진 애착 유형이 두 가지 인지적 경로에 어떤 영향을 미치는지 살펴보았다. 구체적으로, 안정 애착을 가진 개인이 (인지적 지속성이 아닌) 인지적 유연성 경로를 사용했을 때, 창의성이 향상된다고 예측하였다. 미국 피험자를 대상으로 한 온라인 실험은 본 연구의 가설을 지지하고 있다. 본 연구의 결과는, 조직 내 창의성 향상에 있어서 안정 애착이 (인지적 지속성이 아닌) 인지적 유연성과 더 적합하다는 점을 시사하고 있다.

• Journal of information and communication convergence engineering
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• 제12권2호
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• pp.75-82
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• 2014

Dispersion management (DM), optical phase conjugation (OPC), and the combination of DM and OPC are promising techniques to compensate for optical signal distortion due to group velocity dispersion and nonlinear Kerr effects. The system performance improvement in DM links combined with OPC has been reported; however, the fixed residual dispersion per span (RDPS) usually used in these links restricts the flexibility of link configuration. Thus, in this paper, a flexible optical link configuration with artificially distributed single-mode fiber (SMF) lengths and RDPS in the combination of DM and OPC is proposed. Simulation results show that the best artificial distribution pattern is the gradually descending distribution of SMF lengths and the gradually ascending distribution of RDPS, as the number of fiber spans is increased, regardless of the average RDPS, the optimal net residual dispersion, and the dispersion coefficient of the dispersion compensating fiber.

• Journal of information and communication convergence engineering
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• 제15권4호
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• pp.205-211
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• 2017

Combining dispersion-managed optical links with midway optical phase conjugation (OPC) is a possible method of compensating for optical signal distortion due to group velocity dispersion and nonlinear Kerr effects. Although an improvement in the performance of these optical links has been reported, the fixed residual dispersion per span (RDPS) that is typically used restricts the flexibility of link configurations. Thus, in this paper, a flexible dispersion-managed link configuration, comprising artificial distributions of linearly/nonlinearly incremented RDPS, is proposed. Simulations show that a descending distribution of RDPS before the midway OPC, and an ascending distribution of RDPS after the midway OPC, gives the best artificial distribution pattern as the number of fiber spans is increased, regardless of the RDPS incrementation method.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2665-2671
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• 2000

Dimensional Synthesis, which is apart of kinematic synthesis, is to determine the dimensions of a mechanism of preconceived typer for a specified task and prescribed performance. In this paper, in an effort to provide designers with flexibility, a dimensional approximate synthesis method is presented for utilizing prescribed tolerance both the displacement and joint positions of a mechanism to be synthesized. For this, a constrained optimization problem is formulated with displacement parameters and joint positions as variables. The proposed method is applied to the synthesis of a 5-SS multi link suspension mechanism. The method discussed here, however, can be easily applied to any mechanism of which the kinematic constraint equations can be derived.

• 동력기계공학회지
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• 제5권2호
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• pp.79-86
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• 2001

A method is presented for generating the path which significantly reduces residual vibration of the redundant, flexible robot manipulator in the presence of obstacles. The desired path is optimally designed so that the system completes the required move with minimum residual vibration, avoiding obstacles. The dynamic model and optimal path are effectively formulated and computed by using special moving coordinate, called VLCS, to represent the link flexibility. The path to be designed is developed by a combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems. The concept of correlation coefficients is used to select the minimum number of design variables. A planar three-link manipualtor is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate path, in the presence of obstacles.

• 전기학회논문지
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• 제57권7호
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• pp.1235-1240
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• 2008

In this paper, we presented an active RFID system in 2.45GHz range including LNA, Mixer and gain block. And in this work, a link budget model for RFID applications are proposed. We describe the detailed design and implementation of our system. Our components in RFID system has features such as low Noise Figure, reliable energy budget, and standard compliance with ISO 18000-4. Our receiver is effective for development and evaluation of prototype applications because of the flexibility of the design hardware. So, our platform will be suitable for versatile item management applications.

• 컴퓨터교육학회논문지
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• 제3권1호
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• pp.177-189
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• 2000

본 연구에서는 의미망 이론을 웹 코스웨어에 적용하기 위한 효과적인 코스웨어 설계 모델을 구안하고 웹에서 운영할 수 있는 국사과 웹 코스웨어를 구현하였다. 웹 코스웨어의 설계 모델은 구성주의 학습모델 중에서 인지적 융통성 모델을 응용하였고 의미망을 활용한 하이퍼텍스트기법을 적용하여 내용 주제간 관계의 유형을 정의하였다. 이를 바탕으로 내용 지식의 지도를 개발하였으며 국사과 지식 데이터베이스를 구축하는 방안을 제시하고 구현하였다.