A NOTE ON CONSTRUCTING $2^{n}3^1$ AND $2^{1}3^3$ DESIGNS WHEN LINEAR TERMS ARE ESSENTIAL

LIAU PEN-HWANG The Korean Statistical Society 2005 Journal of the Korean Statistical Society Vol.34 No.2

Under the assumption that the three-level factors are quantitative, the linear effects are taken more attention than the quadratic effects of the interaction terms. Webb (1971) presented some small incomplete factorial designs that are mixed two- and three-level designs with 20 or fewer runs. The designs provided the estimating linear-by-linear components of interactions between the three-level factors; moreover, they could also offer estimation of interactions that interest the experiments. Webb used ad hoc methods to find these plans; hence, there was still no unified structure to those experiments. In this paper, we develop the methods to construct the $2^{n}3^3$ and $2^{1}3^3$ designs. The designs constructed by these methods not only supply orthogonal estimates of all the main effects but also permit estimation of all the two-factor interactions not involving the quadratic effects. Furthermore, the designs we find are nearly orthogonal.

Binary Soliton-Like Rateless Coding for the Y-Network

Liau, A.,Yousefi, S.,Il-Min Kim IEEE 2011 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.59 No.12

<P>For the binary erasure channel, Luby Transform (LT) and Raptors codes have been shown to achieve capacity by carefully designed degree distributions for multicasting scenarios. Generalizing fountain codes to multihop networks requires transport nodes to perform network coding (NC). However, if intermediate nodes perform decentralized NC blindly, the statistical properties imposed by the fountain code are lost, and thus, a Gaussian elimination decoder must be used at the sink at the cost of significant increase in complexity compared to a belief propagation (BP) decoder. Addressing this problem, in this paper, we propose a new protocol, namely Soliton-like rateless coding (SLRC), by exploiting the benefits of fountain coding and NC coding over a Y-network. Ensuring key properties of the fountain code are preserved; BP can be effectively applied when transport nodes perform NC. Additionally, the proposed coding protocol is resilient to nodes churn rates. The SLRC scheme is evaluated against buffer-and-forwarding, and the distributed LT (DLT) codes; SLRC exhibits a 5% reduction in overhead compared to the state of the art DLT code at high decoding success rates. Simulations show that the proposed scheme preserves the benefits of NC and fountain coding.</P>

Digital Twin concept for smart injection molding

Liau, Y,Lee, H,Ryu, K IOP Publishing 2018 IOP conference series. Materials science and engin Vol.324 No.-

The influence of contacts erosion on the SF₆ arc

Liau, V K,Lee, B Y,Song, K D,Park, K Y Institute of Physics [etc.] 2006 Journal of physics. D, applied physics Vol.39 No.10

<P>In circuit breakers, high temperature arcing may lead to material erosion at the contacts. In this paper, numerical investigations have been performed in order to study the arc behaviours under the influence of copper vapours contamination in a simple Laval nozzle. The arc is assumed to be in local thermodynamic equilibrium. The erosion rate is estimated by considering the energy balance processes at the contact surface. Computations have been performed by a commercial computational fluids dynamics package (PHOENICS). The effects of contact polarity have also been investigated. It has been found that the presence of copper vapours cools down the arc temperature at the region close to the contacts. However, at current zero, the copper vapours concentration is very low. Post arc simulation has been performed in order to determine the critical rate of rise of recovery voltage (RRRV). Good agreement has been achieved with the experimental measurement of RRRV. It has been predicted that the contact erosion has a negligible effect on the interruption capability of the breaker.</P>

RESIDUALS IN MINIMAL RESOLUTION IV DESIGNS

Liau, Pen-Hwang The Korean Statistical Society 2003 Journal of the Korean Statistical Society Vol.32 No.3

In unreplicated factorial or fractional factorial experiments, the presence of one or more outliers can seriously affect the analysis of variance. Using the normal plot of t residuals to identify outliers in factorial or fractional factorial is an easy method to find these dubious points. In some cases, the t residuals form the identical pairs. One can not tell from the plot which is doubtful. This phenomenon occurs for all minimal designs of resolution IV, which fits the model containing all main effects and some two-factor interactions, whether it is orthogonal or not. In these kinds of models, when we drop one point or two points (not foldover pair) from the fraction, the phenomenon of identical pairs of t residuals may still occur. In this paper, the theoretical background of the phenomenon and its sequences will be investigated in detail.

Numerical Study of SF6 arc with Copper Contamination

Liau Vui-Kien,Lee Byeong-Yoon,Song Ki-Dong,Park Kyong-Yop The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrophysics Vol.5C No.6

The present model of a SF6 arc accounts for the copper vapour contamination from the electrodes inside a Laval nozzle of a circuit breaker. Steady state simulations have been done for the arc with electrode gap of 60mm and DC electric current of 500A, 1000A and 1500A for both cases with and without copper contamination. The effects of electrode polarity are considered for the arc current of 1000A. It was found out that evaporation of copper from the anode results in a cooling of the arc in a region close to the electrodes. The electrical potential across the electrodes is not sensitive to the presence of copper vapour, typically less than $4\%$ difference. Transient analysis has been done in order to obtain the arc properties at current zero. The arc current is increased linearly from -1000 to 0A when the upstream electrode is cathode with constant dI/dt of $27.0A/{\mu}s$ (or decreased linearly from 1000 to 0A when upstream electrode is anode). It has been predicted that the presence of copper vapour reduces the interruption capability of the breaker.

Framework of Automated Inspection System for Real-time Injection Molding

YeeYeng Liau,Kwangyeol Ryu 대한산업공학회 2017 대한산업공학회 춘계학술대회논문집 Vol.2017 No.4

With the increase of demand in plastic products over decades, plastic injection molding has evolved and become one of the most common processes to produce various shape and dimension of plastic parts for various industries. The difficulty of quality inspection especially during the real-time production increases with the complexity in process such as cycle time, large quantity produced in one cycle, orientation of parts for inspection as well as various types of defects in the parts molded. Therefore, most of the inspection of parts or products manually done after production, referred to as off-line inspection. With real-time inspection, the defect can be detected immediately and prevent overproduction of defect parts. Besides, data of processing parameters at the moment of defect occurs can be collected and used to monitor and control the process parameters. Hence, this paper is to propose a framework to design an automated inspection system for injection molding that includes function of visual inspection, handling of parts for inspection, classification and extraction of defects in real-time.

Assessment of Manual Injection Mold Assembly to Facilitate Human-robot Collaboration

YeeYeng Liau,Kwangyeol Ryu 한국경영과학회 2018 한국경영과학회 학술대회논문집 Vol.2018 No.04

Mold assembly is the most critical steps in the mold making process. All the machined parts have to be assembled accurately at the correct position with appropriate procedures to ensure the mold works functionality. In current practice, mold assembly is performed manually. Mold assembly job requires personnel with a comprehensive understanding of the mold structure because there are wide variety numbers and types of components to be manufactured and assembled. However, the mold industry is currently lack of mold professionals to perform the job. In addition, heavy weight of parts and repetitive motion during assembly caused ergonomics problems on worker. Hence, for the purpose to overcome these problems, application of human-robot collaboration (HRC) systems is proposed in the mold assembly. Manual mold assembly workstation assessment, such as Methods-Time Measurement (MTM) is needed before implementation of robots to collaborate with human operator in order to evaluate the mold assembly process from the aspects of assembly sequences and methods, ergonomics and productivity. The results of the assessment will be used to propose suggestions and assist decision making on procedures which required implementation of robots to relieve ergonomics issues on human worker, determine the collaborative task sequences in mold assembly and selection of robot end-effector and model. Furthermore, human-robot collaboration systems with inspection capability will also increase the accuracy and productivity of the mold assembly process.

[A 7.4] Framework of Automated Inspection System for Real-time Injection Molding

YeeYeng Liau,Kwangyeol Ryu 한국시뮬레이션학회 2017 한국시뮬레이션학회 학술대회집 Vol.2017 No.-

With the increase of demand in plastic products over decades, plastic injection molding has evolved and become one of the most common processes to produce various shape and dimension of plastic parts for various industries. The difficulty of quality inspection especially during the real-time production increases with the complexity in process such as cycle time, large quantity produced in one cycle, orientation of parts for inspection as well as various types of defects in the parts molded. Therefore, most of the inspection of parts or products manually done after production, referred to as off-line inspection. With real-time inspection, the defect can be detected immediately and prevent overproduction of defect parts. Besides, data of processing parameters at the moment of defect occurs can be collected and used to monitor and control the process parameters. Hence, this paper is to propose a framework to design an automated inspection system for injection molding that includes function of visual inspection, handling of parts for inspection, classification and extraction of defects in real-time.

Framework of Automated Inspection System for Real-time Injection Molding

YeeYeng Liau,Kwangyeol Ryu 한국경영과학회 2017 한국경영과학회 학술대회논문집 Vol.2017 No.4

With the increase of demand in plastic products over decades, plastic injection molding has evolved and become one of the most common processes to produce various shape and dimension of plastic parts for various industries. The difficulty of quality inspection especially during the real-time production increases with the complexity in process such as cycle time, large quantity produced in one cycle, orientation of parts for inspection as well as various types of defects in the parts molded. Therefore, most of the inspection of parts or products manually done after production, referred to as off-line inspection. With real-time inspection, the defect can be detected immediately and prevent overproduction of defect parts. Besides, data of processing parameters at the moment of defect occurs can be collected and used to monitor and control the process parameters. Hence, this paper is to propose a framework to design an automated inspection system for injection molding that includes function of visual inspection, handling of parts for inspection, classification and extraction of defects in real-time.