• Journal of the Korean Institute of Intelligent Systems
• /
• v.18 no.1
• /
• pp.100-108
• /
• 2008

This paper proposes a method of adaptively generating a gait pattern of biped robot. The gait synthesis is based on human's gait pattern analysis. The proposed method can easily be applied to generate the natural and stable gait pattern of any biped robot. To analyze the human's gait pattern, sequential images of the human's gait on the sagittal plane are acquired from which the gait control values are extracted. The gait pattern of biped robot on the sagittal plane is adaptively generated by a genetic algorithm using the human's gait control values. However, galt trajectories of the biped robot on the sagittal Plane are not enough to construct the complete gait pattern because the bided robot moves on 3-dimension space. Therefore, the gait pattern on the frontal plane, generated from Zero Moment Point (ZMP), is added to the gait one acquired on the sagittal plane. Consequently, the natural and stable walking pattern for the biped robot is obtained.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.11
• /
• pp.1151-1157
• /
• 2009

Ensuring both product quality and reducing material cost are important issue for the design of the piping system of an air conditioner outdoor unit. This paper describes a shape optimization that achieves mass reduction of an air conditioner piping system while satisfying two design constraints on resonance avoidance and the maximum stress in the pipes. In order to obtain optimized design results with various analysis fields considered simultaneously, an automated multidisciplinary analysis system was constructed using PIAnO v.2.4, a commercial process integration and design optimization(PIDO) tool. As the first step of the automated analysis system, a finite element model is automatically generated corresponding to the specified shape of the pipes using a morphing technique included in HyperMesh. Then, the performance indices representing various design requirements (e.g. natural frequency, maximum stress and pipe mass) are obtained from the finite element analyses using appropriate computer-aided engineering(CAE) tools. A sequential approximate optimization(SAO) method was employed to effectively obtain the optimum design. As a result, the pipe mass was reduced by 18 % compared with that of an initial design while all the constraints were satisfied.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.8
• /
• pp.1598-1603
• /
• 2003

A microstrip array antenna is designed and tested for satellite broadcasting receptions. The Sierpinski equilateral triangular patch and SSFIP(slot­strip­foam­inverted patch) structures are used. The Sierpinski geometry is composed of 3 equilateral triangular patch and is easy to generate a circular polarization by sequential rotation array techniques. This 1${\times}$3 Sierpinski equilateral triangular patch antenna is extended to 8${\times}$2 array antenna for satellite broadcasting receptions. The measurement results of the reflection coefficients and the radiation patterns of the manufactured array antenna show good agreements with the simulation results.

• Journal of Power System Engineering
• /
• v.11 no.1
• /
• pp.5-15
• /
• 2007

In the recently released accident-investigation report on blade failure, almost 70% of blade failures was found at low pressure turbine blades, and it is well known that main cause is due to the vibration modes. This paper describes the systematic approach on the root cause of the blade failure at L 0 stage, 30MW single flow industrial steam turbine which had tripped by high vibration after ten-month commercial operation. A fracture was found at the only one damping wire hole of 59 blades, and crack was detected at three damping wire holes by NDT. According to the analysis result for the crack fracture surface and the chain of the sequential operational events, we come to the conclusion that a typical high cycle fatigue is the most dominant factor caused to the blade failure, the resonance frequency margin was narrowed by the cut damping wire and the high cycle vibration was amplified, and then the blade was broken at once by the centrifugal force when the crack reached the critical size.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.1
• /
• pp.57-64
• /
• 2000

We describe a parallel implementation for the large-eddy simulation(LES) of stratified and rotating turbulence based on MPI. The parallelization strategy is specified by eliminating the tridiagonal solver with explicit method and by domain decompositions for solving the poisson equation. In this simulation we have run on CRAY-T3E under the message passing platform MPI with a various domain decomposition and the scalability of this parallel code of LES are also presented. The result shows that we can gain up to 16 times faster speed up on 64 processors with xyz-directional domain decomposition and scalable up to $128{\times}128{\times}$ which processing time is almost similar to that of $40{\times}40{\times}40$ on a single processor machine with a sequential code.

• Journal of Korean Society of Transportation
• /
• v.21 no.6
• /
• pp.89-99
• /
• 2003

Considering a path represented by a sequence of link numbers in a network, the vine is differentiated from the loop in a sense that any link number can be appeared in the path only once, while more than once in the loop. The vine provides a proper idea how to account for complicated travel patterns such as U-turn and P-turn witnessed nearby intersections in urban roads. This paper proposes a new algorithm in which the vine travel pattern can be considered for finding K number of sequential paths. The main idea of this paper is achieved by replacing the node label of the existing Yen's algorithm by the link label technique. The case studies show that the algorithm properly represent the vine travel patterns in searching K number of paths. A noticeable result is that the algorithm may be a promising alternative for ITS deployment by enabling to provide reasonable route information including perceived traveler costs.

• Proceedings of the KIEE Conference
• /
• 2004.10a
• /
• pp.126-128
• /
• 2004

This paper deals with an automatic optimum design based on capacity for a synchronous reluctance motor (SynRM). The focus of this paper is the design relative to the output power on the basis of rotor shape of a SynRM in each capacity. And optimization algorithm is used by means of sequential unconstrained minimization technique(SUMT). The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate nonlinear solutions. The proposed procedure allows to define the rotor geometric dimensions according to capacity starting from an existing motor or a preliminary design.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.11
• /
• pp.577-581
• /
• 2006

This paper deals with an automatic rotor design functional standard computation based on torque/volume for a synchronous reluctance motor(SynRM). The focus of this paper is the design relative to the torque/volume on the basis of each rated watt according to the rotor diameters of a SynRM. The coupled finite elements analysis (FEA) & sequential unconstrained minimization technique (SUMT) have been used to evaluate design solutions. The proposed procedure allows to define the rotor geometric design function according to the rotor diameter and rated watt starting from an existing motor or a preliminary design.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.709-710
• /
• 2006

This paper deals with an automatic rotor design functional standard computation based on torque/volume for a synchronous reluctance motor (SynRM). The focus of this paper is the design relative to the torque/volume on the basis of each rated watt according to the rotor diameters of a SynRM. The coupled finite elements analysis (FEA) & sequential unconstrained minimization technique (SUMT) have been used to evaluate design solutions. The proposed procedure allows to define the rotor geometric design function according to the rotor diameter and rated watt starting from an existing motor or a preliminary design.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.839-845
• /
• 2003

This paper introduces multichannel blind source separation (BSS) and multichannel blind deconvolution (MBD) based on higher order statistics of signals from convolutive mixtures. In particular, we are concerned with the case that the number of inputs is the same as the number of outputs. Simulations for two input two output cases are carried out and their performances are assessed. One of the major applications of those sequential algorithms (BSS and MBD) is demonstrated through the fault signal detection from only a single measurement of rotating machine, which offers a certain degree of practicability in the engineering field such as machine health monitoring or condition monitoring.