• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.936-941
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• 2014

Walking mechanisms are very important for legged robots to ensure their stable locomotion. In this research, Klann-linkage is suggested as a walking mechanism for a water-running robot and is optimized using level average analysis. The structure of the Klann-linkage is introduced first and design variables for the Klann-linkage are identified considering the kinematic task of the walking mechanism. Next, the design problem is formulated as a path generation optimization problem. Specifically, the desired path for the foot-pad is defined and the objective function is defined as the structural error between the desired and the generated paths. A process for solving the optimization problem is suggested utilizing the sensitivity analysis of the design variables. As a result, optimized lengths of Klann-linkage are obtained and the optimum trajectory is obtained. It is found that the optimized trajectory improves the cost function by about 62% from the initial one. It is expected that the results from this research can be used as a good example for designing legged robots.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1165-1168
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• 2002

Knowledge acquisition is the process that extracts the required knowledge from available sources, such as experts, textbooks and databases, for incorporation into a knowledge-based system. Knowledge acquisition is described as the first step in building expert systems and a major bottleneck in the efficient development and application of effective knowledge based expert systems. One cause of the problem is that the process of human reasoning we need to understand for knowledge-based system development is not available for direct observation. Moreover, the expertise of interest is typically not reportable due to the compilation of knowledge which results from extensive practice in a domain of problem solving activity. This is also a problem of modeling knowledge, which has been described as not a problem of accessing and translating what is known, but the familiar scientific and engineering problem of formalizing models for the first time. And this formalization process is especially difficult for knowledge engineers who are often faced with the difficult task of creating a knowledge model of a domain unfamiliar to them. In this paper, we propose an automated knowledge acquisition tool which is based on an implementation of the Inferential Modeling Technique. The Inferential Modeling Technique is derived from the Inferential Model which is a domain-independent categorization of knowledge types and inferences ［Chan 1992］. The model can serve as a template of the types of knowledge in a knowledge model of any domain.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.195-214
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• 2016

Monitoring of impact loads is a very important technique in the field of structural health monitoring (SHM). However, in most cases it is not possible to measure impact events directly, so they need to be reconstructed. Impact load reconstruction refers to the problem of estimating an input to a dynamic system when the system output and the impulse response function are usually known. Generally this leads to a so called ill-posed inverse problem. It is reasonable to use prior knowledge of the force in order to develop more suitable reconstruction strategies and to increase accuracy. An impact event is characterized by a short time duration and a spatial concentration. Moreover the force time history of an impact has a specific shape, which also can be taken into account. In this contribution these properties of the external force are employed to create a sample-force-dictionary and thus to transform the ill-posed problem into a sparse recovery task. The sparse solution is acquired by solving a minimization problem known as basis pursuit denoising (BPDN). The reconstruction approach shown here is capable to estimate simultaneously the magnitude of the impact and the impact location, with a minimum number of accelerometers. The possibility of reconstructing the impact based on a noisy output signal is first demonstrated with simulated measurements of a simple beam structure. Then an experimental investigation of a real beam is performed.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.944-951
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• 2015

Pulse Width Modulation (PWM) techniques are increasingly employed for PWM inverter fed induction motor drive. Among various popular PWM methods used, Selective Harmonic Elimination PWM (SHEPWM) has been widely accepted for its better harmonic elimination capability. In addition, using SHEPWM, it is also possible to maintain better voltage regulation. Hence, in this paper, an attempt has been made to apply Bacterial Foraging Algorithm (BFA) for solving selective harmonic elimination problem. The problem of voltage harmonic elimination together with output voltage regulation is drafted as an optimization task and the solution is sought through proposed method. For performance comparison of BFA, the results obtained are compared with other techniques such as derivative based Newton-Raphson method, and Genetic Algorithm. From the comparison, it can be observed that BFA based approach yields better results. Further, it provides superior convergence, reduced computational burden, and guaranteed global optima. The simulation results are validated through experimental findings.

• Korean Journal of Human Ecology
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• v.18 no.2
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• pp.313-324
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• 2009

The study is to investigate mothers' parental beliefs about child development and the children's developmental tasks, and to explore the relationship between mother's parental beliefs and child-rearing behaviors. The subjects are 113 pairs of 4- to 5-year-old children and their mothers. For measuring maternal beliefs about child-development, 'beliefs about development scale' and 'child-rearing beliefs scales' were used. For mother's child-rearing behaviors, 'child rearing behavior observation scale' was used. The main results were: first, mothers value the cognitive theory and 'autonomous behavior' higher than 'conforming behavior' in developing their children. Second, there were no differences in mother's parenting beliefs in the factors of 'gender of their children' and 'maternal job status', while there were significant differences in maternal beliefs according to the levels of mother's education and family income. Third, sub-scales of their parenting beliefs were correlated with interactive behaviors between them and their children. The more mothers put importance on cognitive theory and children's autonomous behaviors, the more their supportive child-rearing behaviors during child-mother task solving situations were showed.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2050-2059
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• 1999

Multiprocessor scheduling problem has been an important research area for the past decades. The problem is defined as finding an optimal schedule which minimizes the parallel execution time of an application on a target multiprocessor system. Duplication Based Scheduling (DBS) is a relatively new approach for solving multiprocessor scheduling problems. This paper classifies DBS algorithms into two categories according to the task duplication method used. The paper then presents a new DBS algorithm that extracts the strong features of the two categories of DBS algorithms. The simulation study shows that the proposed algorithm achieves considerable performance improvement over existing DBS algorithms with similar time complexity.

• Journal of Engineering Education Research
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• v.18 no.3
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• pp.13-23
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• 2015

This paper attempts to take an in-depth study of the importance of teams and their creativity according to changes of recent design paradigm in engineering and to draw conclusions of the sub-domains and their element extraction. For this purpose, theoretical consideration was reviewed to present the definition of creativity and its sub-domains and elements. Besides, the two steps of expert validation test were conducted to extract the definition of creativity and its sub-domains and elements. The team creativity is defined as a team ability to come up with fresh and useful ideas and to lead them to get meaningful results through cooperative interactions among team members to solve problems given to them based on each member's creativity. Totally, 4 subs -domains and 16 sub-elements were extracted to get to know their influence on the team creativity. This includes a team size, characteristics of team members, and a team structure in team organization domain. To evaluate team atmosphere, elements such as sensibility, fellowship, teamwork, reliability, autonomy and open minded feature are included. In the team activity domain, strategies for solving problems, activities for divergent thinking, activities for convergence thinking and team interaction are included. Also, the sub-domain for team management includes a task, process and conflict management.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1330-1341
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• 1993

The kinematic synthesis deals with the systematic design of mechanisms for a given performance. The area of synthesis may be grouped into two categories to determine the type and to size the dimensions of a mechanism for a specified task. In this paper, using a database of mechanisms a designer can determine the type of mechanism conveniently and design equations are automatically generated for a given input performance. The solving method of design equations utilizes an optimization routine to obtain roots effectively. The linkages of 4, 6, and 8bars with revolute joints are considered in this study but may be extended to linkages of more bars.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.168-175
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• 2001

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do net quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

• Journal of Gifted/Talented Education
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• v.11 no.2
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• pp.87-106
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• 2001

Identification and selection the mathematically gifted child must be based on it's definition. So, we have to consider not only IQ or high ability in mathematical problem solving, but also mathematical creativity and mathematical task commitment. Furthermore, we must relate our ideas with the programs to develop each student's hidden potential. This study is focused on the discrimination of the candidates who would like to enter the elementary school level mathematics gifted education program. To fulfill this purpose, I considered the criteria, principles, methods, and tools. Identification is not exactly separate from selection and education. So, it is important to have long-term vision and plan to identify the mathematically gifted students.