• Steel and Composite Structures
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• v.16 no.4
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• pp.375-387
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• 2014

The purpose of this paper is to propose a method for evaluation of varying stiffness coefficients of tailored conical shells (TCS). Furthermore, a comparison between buckling loads of these shells under axial load with the different fiber path is performed. A circular truncated conical shell subjected to axial compression is taken into account. Three different theoretical path containing geodesic path, constant curvature path and constant angle path has been considered to describe the angle variation along the cone length, along cone generator of a conical shell are offered. In the TCS with the arbitrary fiber path, the thickness and the ply orientation are assumed to be functions of the shell coordinates and influencing stiffness coefficients of the structure. The stiffness coefficients and the buckling loads of shells are calculated basing on classical shells theory (CST) and using finite-element analysis (FEA) software. The obtained results for TCS with arbitrary fiber path, thickness and ply orientation are derived as functions of shell longitudinal coordinate and influencing stiffness coefficients of structures. Furthermore, the buckling loads based on fiber path and ply orientation at the start of tailored fiber get to be different. The extent of difference for tailored fiber with start angle lower than 20 degrees is not significant. The results in this paper show that using tailored fiber placement could be applied for producing conical shells in order to have greater buckling strengths and lower weight. This work demonstrates the use of fiber path definitions for calculated stiffness coefficients and buckling loads of conical shells.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2437-2445
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• 1993

In this work, a new method is presented for generating the manipulator path which significantly reduces residual vibration under the torque constraints. The desired path is optimally designed so that the required movement can be achieved with minimum residual vibration. From the previous research works, the dynamic model had been established including both the link and the joint flexibilities. The performance index is selected to minimize the maximum amplitude of residual vibration. 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, i.e. Fourier coefficients, the only ones which have a considerable effect on the reduction of residual vibration. A two-link Manipulator is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate manipulator path to both of unlimited and torque-limited cases.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.78-86
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• 1998

This paper presents a numerical method of the minimum-time trajectory planning for a robot manipulator amid obstacles. Each joint displacement is represented by the linear combination of the finite-term quintic B-splines which are the known functions of the path parameter. The time is represented by the linear function of the same path parameter. Since the geometric path is not fixed and the time is linear to the path parameter, the coefficients of the splines and the time-scale factor span a finite-dimensional vector space, a point in which uniquely represents the manipulator motion. The displacement, the velocity and the acceleration conditions at the starting and the goal positions are transformed into the linear equality constraints on the coefficients of the splines, which reduce the dimension of the vector space. The optimization is performed in the reduced vector space using nonlinear programming. The total moving time is the main performance index which should be minimized. The constraints on the actuator forces and that of the obstacle-avoidance, together with sufficiently large weighting coefficients, are included in the augmented performance index. In the numerical implementation, the minimum-time motion is obtained for a planar 3-1ink manipulator amid several rectangular obstacles without simplifying any dynamic or geometric models.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.597-602
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• 2008

The experiment of performance about closed-wet cooling tower(CWCT) was conducted in this study. The test section has the cooling water that flows from top part of a heat exchanger that has an entrance of cooling water with one and multi path. The heat exchanger consists of 15.88mm tubes with ten rows and ten columns and staggered arrangement. In this experiment, heat and mass transfer coefficients and range are calculated with variations of cooling water and path. The results indicated that operating CWCT using two path have the high values of heat and mass transfer coefficients and range than one path.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.165-170
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• 1995

This study was carried out to investigate the correlation of agronomic characters, their path coefficients in 2, 3 and 4-year old ginseng plants, and to provide a useful information for ginseng breeding. Correlation coefficients between stem fen변h, number of leaves and number of Iraflets in 2-year age, and stem diameter and leaf length in 3-year age showed highly significant correlation with number of fruits and root weight in 4-year age. The path coefficient analysis indicated that stem length and number of leaflets might give indirect effects on root weight regardless of plant age. On the other hand, stem length and number of leaflets in 2-year age and, stem diameter and leaf length in 3-year age showed direct effects on root weight in 4-year old ginseng. These results may be used for selection of high-yielding ginseng plants. Key words Selection information, correlation and path coefficient analysis.

• Korean Management Science Review
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• v.23 no.2
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• pp.41-57
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• 2006

The purposes of this research are to identify causalities among flow and customer loyalty In Chinese online games, and to identify the factors by which flow are influenced. This research tests the model with Chinese on-line game users and compare this result with Korea and Japanese results which were conducted by Lee's research. These implications are thought to be helpful for Korean online game companies to understand the Chinese online game user and to develop the penetration strategies. The results indicated that significant Path coefficients to flow were the convenience of operator, the provision of information, the reality of design. The results indicated that significant path coefficients to customer loyalty were the involvement of virtual community and flow. The involvement of virtual community to flow was not significant but to customer loyalty was significant. The provision of information was negatively influenced on flow. The result of comparison indicated that the path coefficients were different among nations. Korea online game companies need to develop the indigenized online game and to Provide the information to their Chinese partner correctly and quickly.

• Journal of Distribution Science
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• v.13 no.8
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• pp.81-90
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• 2015

Purpose - To vitalize a market or develop a new one, companies frequently release new products into the market, often by shortening the time to market, called the release period. This research aims to investigate the purchase intention behavior of consumers in terms of buying new products at the time of product release based on the release speed. Research Design, Data, and Methodology - The research reviews the influence of relative advantage, complexity, and compatibility among innovative attributes of new products, as proposed by Rogers. Moreover, it examines the moderating effect of the innovative new product attributes in terms of speed of obsolescence of old products and how that influences consumer purchase behavior. Additionally, this study tests the research hypotheses using empirical analysis. Results - The analysis demonstrated that the relative predominance (H1) and suitability (H3) of new products had a statistically significant positive influence on new product purchase intention. However, the complexity (H2) of new products had a statistically significant positive influence on new product purchase intention in contrast to its predicted sign (-). The results of the moderating effect of the old product use period were as follows. H4-1 was not supported since the difference between the path coefficients of the group with the low level old product use period and the group with the high level, represented by the relationship of relative predominance and new product purchase intention, was not statistically significant. H5-1 was also not supported since the difference between the path coefficients of the group with the low level of old product use period and the group with the high level, represented by the relationship of complexity and new product purchase intention, was not statistically significant. However, H4-2 was supported since the difference between the path coefficients of the group with the low level of old product use frequency and the group with the high level, represented by the relationship of relative advantage and new product purchase intention was statistically significant. H5-2 was not supported since the difference between the path coefficients of the group with the low level of old product use frequency and the group with the high level, represented by the relationship of complexity and new product purchase intention, was not statistically significant. H6-2 was also not supported since the difference between the path coefficients of the group with the low level of old product use frequency and the group with the high level, represented by the relationship of compatibility and new product purchase intention, was not statistically significant. Conclusion - According to the results, only H4-2 among the hypotheses on the moderating effect of the old product use period and use frequency was statistically significant. Future research should focus on carrying out a detailed review of the hypothesis on the moderating effect of the old product usage period and frequency, find the cause, and connect this to potential new research.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.25-29
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• 1997

In this thesis, we construct the microrobot succor system and navigate the real-time path planning and visual tracking of each robot. The system consists robots, vision system and a host computer. Because the robots are free-ranging mobile robot, it is needed to make and gallow the path. The path is planned and controlled by a host computer, ie. Supervisory control system. In path planning, we suggest a cost function which consists of three terms. One is the smoothness of the path, another is the total distance or time, and the last one is to avoid obstacles. To minimize the cost function, we choose the parametric cubic spline and update the coefficients in real time. We perform the simulation for the path planing and obstacle avoidance and real experiment for visual tracking

• Korea Trade Review
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• v.47 no.6
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• pp.135-171
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• 2022

This study is to find out how psychological characteristics and management capabilities of small manufacturers influence business performance through parameters including self-efficiency, network, and collaboration strategies. The survey was implemented between December 26, 2017 and January 15, 2018. The final 439 valid questionnaires were collected and used for analysis. The results were followed. First, the relationship between psychological characteristics and self-efficiency, and the path coefficient for psychological characteristics and network were significant. Second, management capabilities was related to self-efficiency, and the path factor for managing capability and network relationships was significant. Lastly, the path coefficients for self-efficiency and collaboration strategies were not significant, and the path coefficients for network and collaboration strategies were significant.

• Journal of Power System Engineering
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• v.5 no.2
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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.