• Imaging Science in Dentistry
• /
• v.30 no.1
• /
• pp.16-22
• /
• 2000

Purpose : To evaluate the bone densities measured on copper-equivalent image of cross sectional view of mandibular edentulous premolar area obtained by multifuctional panoramic x-ray machine, PM 2002 CC with transversal slicing system. Materials and Methods: Panoramic cross sectional views with 8 mm focal layer of aluminum step and blocks, of hydroxyapatite (RA) step, 6 HA blocks and copper step wedge having 0.03 mm thickness of each step, and of 3 bone blocks cutted by 8 mm thickness mesiodistally and a dry mandible with copper step wedge were taken by using transversal slicing system in PM 2002 Cc. All reference-equivalent images were made and analyzed by NIH image program. Results: The average copper-equivalent value of cancellous bone of bone blocks on the panoramic cross sectional view was 0.026 ± 0.020 mm Cu. The calculated average bone density was 0.38g/cm². There was no significant difference (P>0.1) between the bone densities on intraoral digital view and on the panoramic digital cross sectional view. Conclusion: The copper-equivalent image of panoramic digital cross sectional view obtained by PM 2002 CC with very thin copper step wedge was supposed to be useful to measure the bone density of cancellous bone of mandible at the premolar edentulous area.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2006.04a
• /
• pp.240-247
• /
• 2006

Piezoelectric sensor-based health monitoring technique using a two-step support vector machine (SYM) classifier is discussed for damage identification of a railroad track. An active sensing system composed of two PZT patches was investigated in conjunction with both impedance and guided wave propagation methods to detect two kinds of damage of the railroad track (one is a hole damage of 0.5cm in diameter at web section and the other is a transverse cut damage of 7.5cm in length and 0.5cm in depth at head section). Two damage-sensitive features were extracted one by one from each method; a) feature I: root mean square deviations (RMSD) of impedance signatures and b) feature II: wavelet coefficients for $A_0$ mode of guided waves. By defining damage indices from those damage-sensitive features, a two-dimensional damage feature (2-D DF) space was made. In order to minimize a false-positive indication of the current active sensing system, a two-step SYM classifier was applied to the 2-D DF space. As a result, optimal separable hyper-planes were successfully established by the two-step SYM classifier: Damage detection was accomplished by the first step-SYM, and damage classification was also carried out by the second step-SYM. Finally, the applicability of the proposed two-step SYM classifier has been verified by thirty test patterns.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.1
• /
• pp.283-292
• /
• 2013

This paper aims to propose a new steps of hypothesis testing using analysis process and improvement process in the six sigma DMAIC. The six sigma implementation models proposed in this paper consist of six steps. The first step is to establish a research hypothesis by specification directionality and FBP(Falsibility By Popper). The second step is to translate the research hypothesis such as RHAT(Research Hypothesis Absent Type) and RHPT(Research Hypothesis Present Type) into statistical hypothesis such as $H_0$(Null Hypothesis) and $H_1$(Alternative Hypothesis). The third step is to implement statistical hypothesis testing by PBC(Proof By Contradiction) and proper sample size. The fourth step is to interpret the result of statistical hypothesis test. The fifth step is to establish the best conditions of product and process conditions by experimental optimization and interval estimation. The sixth step is to draw a conclusion by considering practical significance and statistical significance. Important for both quality practitioners and academicians, case analysis on six sigma projects with implementation guidelines are provided.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.1
• /
• pp.35-40
• /
• 2007

The one step type and two step type pole are used in distribution line. If the three phases are not balanced, the communication line can be damaged by induced voltage. This paper calculates the neutral current using KEPCO's distribution system model which is only composed by one step type pole. The used system model is modelled by using ATPDraw and the neutral current is calculated by using EMTP/MODELS. Many cases for abstracting the neutral current characteristics in KEPCO's distribution system are simulated and analyzed.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.5
• /
• pp.2142-2148
• /
• 2015

This paper proposes novel real-time footstep planning and following methods for the navigation of humanoid robots. A footstep command is defined by a walking direction and step lengths for footstep planning. The walking direction is determined by a uni-vector field navigation method, and the allowable yawing range caused by hardware limitation is considered. The lateral step length is determined to avoid collisions between the two legs while walking. The sagittal step length is modified by a binary search algorithm when collision occurs between the robot body and obstacles in a narrow space. If the robot body still collides with obstacles despite the modification of the sagittal step length, the lateral step length is shifted at the next footstep. For footstep following, a walking pattern generator based on a 3-D linear inverted pendulum model is utilized, which can generate modifiable walking patterns using the zero-moment point variation scheme. Therefore, it enables a humanoid robot to follow the footstep command planned for each footstep. The effectiveness of the proposed method is verified through simulation and experiment.

• 한국연소학회:학술대회논문집
• /
• 2012.04a
• /
• pp.195-196
• /
• 2012

This paper describes combustion tuning methodology of double-swirl gas turbine combustor using six sigma tools. This methodology is consist of five steps-Define, Identify, Design, Optimize and Verify (DIDOV). First, the NOx reduction target was defined in the step design; second, the current status of the plant was diagnosed in the step of identify; third, the vital few control parameters to achieve the defined target were determined by analyzing the correlation between the control parameters and NOx emissions in the step of design; fourth, the optimum condition was derived from one of the six sigma tools in the step of optimize; finally, the optimum condition was verified by applying the condition to the gas turbine combustor in the step of verify. As a result of the suggested method, averaged NOx emissions were reduced by more than 70% and the standard deviation was improved by more than 60%. Thus, this methodology can be attributed to the efficient reduction of NOx emission with saving combustion tuning time.

• Korean Journal of Computational Design and Engineering
• /
• v.12 no.1
• /
• pp.8-14
• /
• 2007

In the product design process computer-aided engineering and optimization tolls are widely utilized in order to reduce the total development time and cost. Since several simulation tools are involved in the process, information losses, omissions, or errors are common and the importance of seamless information exchange among the tools has been increased. In this work, ISO STEP standards are adopted to represent the neutral format for structural analysis and optimization. The schema of AP209 defined the information of finite element analysis is used and the new schema is proposed to describe the information of structural optimization based on the STEP methodology. The schema is implemented by EXPRESS, information modeling language, and ST-Developer is employed to generate C++ classes and STEP Rose Library by using the schema denoted. To substantiate the proposed approach, the information access interfaces of the finite element modeling software (FEMAP), structural optimization software(GENESIS) and in-house topology optimization program are developed. Examples are shown to validate the information exchange of finite element analysis and structural optimization using STEP standards.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.506-511
• /
• 2001

This paper presents how redevelopment of the boundary layer in a backward-facing step flow is affected by boundary conditions imposed on velocity at the inlet, top and exit of the flow. A two-dimensional, laminar, incompressible flow over a backward-facing step with an open top boundary has been computed by using numerical methods of second-order time and spatial accuracy and a fractional-step method that guarantees a divergence-free velocity field at all time. The inlet velocity profile above the step is of Blasius type. Along the top boundary, shear-tree and Dirichlet conditions on the streamwise velocity were considered and at the exit fully-developed and convective boundary conditions were examined. (The vertical velocity at all boundaries were assumed to be zero explicitly or implicitly.) From the computed flow fields, the reattachment on the bottom side of shear layer separated from the tip of the step and succeeding redevelopment of the boundary layer were investigated.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1234-1239
• /
• 2003

In the product design process computer-aided engineering and optimization tools are widely utilized in order to reduce the total development time and cost. Since several simulation tools are involved in the process, information losses, omissions, or errors are common and the importance of seamless information exchange among the tools has been increased. In this study ISO STEP standards are adopted to represent the neutral format for CAE/CAO information exchange. The schema of AP209 is used to define the information of finite element analysis and the new schema is proposed to describe the information of structural optimization based on the STEP methodology. The schema is implemented by EXPRESS, information modeling language, and ST-Developer is employed to generate C++ classes and STEP Rose Library by using the schema denoted. To substantiate the proposed approach, the information access interfaces of the finite element modeling software (FEMAP), structural optimization software (GENESIS) and in-house topology optimization program are developed. Examples of the size optimization of a three-bar truss and topology optimization of a MBB beam are shown to validate the information exchange of finite element analysis and structural optimization using STEP standards.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.1
• /
• pp.109-114
• /
• 2016

This paper relates with the performance improvement of CCA (Compact Constellation Algorithm) equalization algorithm by adding the adaptive step size control in order to the minimization of intersymbol interference and additive noise effects that is occurs in the channel for digital radio transmissionl. In general, the fixed step size was used in order to adaptation in equalizer algorithm. But in proposed algorithm, the variable step size were adapted that is proposional to the nonlinear function of error signal for equalization. In order to show the improved equalizatation performance, the output signal constellation of equalizer, residual isi, maximum distortion, MSE and SER were used, then it were compared with the present CCA algorithm. As a result of computer simulation, the adaptive step size CCA has more better performance in the every performance index compared to the fixed step size CCA after in the steay state.