Seungjun Shin

UbiDM: A new paradigm for product design and manufacturing via ubiquitous computing technology

Since ubiquitous technology was introduced in the early 1980s, it has rapidly developed, and been applied to various domains mainly for the improvement of human life. In this article, the authors propose that ubiquitous computing technology can be effectively used for the design and manufacturing of a product by proposing a new paradigm, called UbiDM® (Design and Manufacture via Ubiquitous Computing Technology). The key aspect of UbiDM is the utilisation of the entire product lifecycle information obtained via ubiquitous computing technology for the design and manufacture of the product. The new paradigm can solve many of the problems that have not been properly handled by previous manufacturing paradigms. Specifically, it will address the concept of UbiDM by the following aspects: (1) why there is a need for UbiDM; (2) the essence of UbiDM; (3) enabling technologies; (4) application area; (5) worldwide R&D status; and (6) the societal impacts of UbiDM.

STEP-compliant CNC system for turning: Data model, architecture, and implementation

STEP-NC, a new data model for CAD-CAM-CNC chain, is expected to encompass the whole scope of e-manufacturing. The new data model formalized as ISO 14649 is under development by ISO TC184 SC1 and SC4 for the replacement of the old standard so-called G&M codes, formalized as ISO 6983 which has been used since the 1950s. As the new data model is being established, development and implementation of STEP-compliant CAD/CAM/CNC system based on the new data model is drawing worldwide attention. Several systems have been reported in such international conventions as the ISO Expert Committee Meeting. Up to the present time, all the STEP-CNC systems are intended for milling operation. In this paper, the authors first present STEP-compliant CNC system for turning system including the data model, followed by a generic architecture and functionality. Implementation results obtained from a prototype system called TurnSTEP have been provided. Based on the results, the authors are convinced of the validity of the STEP-NC data model together with the effectiveness of the STEP-CNC system for turning.

Reincarnation of G-code based part programs into STEP-NC for turning applications

As STEP-NC emerges as the new CNC control method and a fundamental means for realizing e-manufacturing, old manufacturing information based on the conventional manufacturing standard will become obsolete. In practice, replacement of G-code based part programs into STEP-NC is a huge task. In this paper, methods to interpret G-code based part programs into STEP-NC code are investigated. G-code is a compact, coded set of numbers for axis movements, while STEP-NC is very comprehensive and includes information about features, operations, strategies, cutting tools, and so on. It is thus very challenging to derive such comprehensive information from the low level G-code information. In this paper, we first clarify what should be given and what may be given, and then present algorithms for deriving STEP-NC information, such as geometric features, operations, etc., from the tool movement (G-code) based on expert reasoning. The algorithms are developed for the turning application. The developed algorithms were implemented and tested on G-code part programs used in actual practice.

Three-dimensional fluid simulation of a plasma display panel cell

In order to understand the discharge characteristics in an alternating current plasma display panel (ac PDP) and optimize it further, a three-dimensional fluid code (FL3P) has been developed. Using this simulator, various three-dimensional features of discharges are investigated in the sustain mode of PDP. First, the striations of wall charge are observed at both the anode and cathode side. Second, the local efficiency is obtained as a function of position. It is mainly divided into the anode region and the cathode region and highest near the anode center. Finally, the effects of various three-dimensional parameters are studied. As one of the examples showing the effect of electrode shaping, the discharge characteristics of a T-shaped electrode cell are compared with those of a conventional cell. The phosphor on barrier ribs contributes to over 44% of the total luminance, but barrier ribs themselves do not play an important role in the overall discharge efficiency. Address electrode width is not always pr...

A green productivity based process planning system for a machining process

In the metal cutting industry, manufacturers have strived to increase energy efficiency and to reduce environmental burdens through the use of dust collectors and waste disposers. It is more beneficial and efficient to apply the front-of-pipe technology that prevents the sources of pollutants and minimises energy use through the redesign of products and the change of process planning and machining operations. In particular, process planning for the environment, called eco-process planning, is central to increasing energy efficiency and reducing environmental burdens because process planning decisions greatly influence machining performance. At present, greenability, a term used to indicate environmental friendliness, has been little considered as a major concern in the process planning stage because process planning decisions have focused on improving productivity aspects that include speed, cost and quality. Thus, it is essential to develop an eco-process planning approach that enables the harmonisation and enhancement of greenability performance while improving productivity performance, termed green productivity (GP). This paper presents the development of a GP-based process planning algorithm that enables the derivation of process parameters for improving GP in machining operations. The core mechanism of the algorithm is the realisation of the process improvement cycle that measures GP performance by the collection of machining data, quantifies this performance by categorical representation and predicts the performance through prediction models. To show the feasibility and applicability of the proposed algorithm, we have conducted an experiment and implemented a prototype system for a turning machining process.

Process-oriented Life Cycle Assessment framework for environmentally conscious manufacturing

Environmental concern requires manufacturers to extend the domain of their control and responsibility across the product’s life cycle. Much of the research has concentrated on assessment of environmental performance through the application of the Life Cycle Assessment (LCA) framework that provides a technical methodology to help identification of environmental impacts of product systems. However, the current LCA framework does not incorporate dynamic and diverse characteristics of manufacturing processes. As a result, the LCA’s referential data will largely deviate from the real ones to an extent that the purpose of LCA is not meaningful. In other words, the current and fixed referential data-based method is not suitable to specify the impact categories related to manufacturing processes. From the perspective of decision making related with environmental impact during manufacturing, the current LCA method carried out in the off-line is hard to apply. As a result, performance index, such as greenability, a major performance index for environment conscious manufacturing cannot be implemented in the real practice. This paper presents the development of a framework (called process-oriented LCA) to realize environmental conscious manufacturing incorporating both greenability and productivity. To show the applicability and validity of this framework, experiments and analysis have been conducted and a prototype system has been implemented for a turning machining process.

P‐57: Striation Phenomenon of Plasma Display Panel (PDP) Cell and Its Application to Efficiency Improvement

The first observation of striation in plasma display panel (PDP) cell by kinetic and fluid simulations is presented. The striation phenomenon in the kinetic simulation is clearer than that in fluid simulation. The striation is due to the self-consistent interaction of plasma, dielectric wall, and applied voltages. Simulation results indicate that the phenomenon occurs due to the non-uniform accumulation of surface charges on the sustain electrodes, which consequently deform the local potential profile. The surface and space charges locally create multiple-tier potential distribution near anode region that makes plasma bunches. The discharge in this region is governed by ionization process, but the cathode discharge depends on the secondary-electron emission process on the dielectric surface. Based on these discharge characteristics, 80 % efficiency increase of PDP cell is obtained due to triggered striation by the modification of front dielectric material and MgO protective-layer.

Super-resolution visible photoactivated atomic force microscopy

Imaging the intrinsic optical absorption properties of nanomaterials with optical microscopy (OM) is hindered by the optical diffraction limit and intrinsically poor sensitivity. Thus, expensive and destructive electron microscopy (EM) has been commonly used to examine the morphologies of nanostructures. Further, while nanoscale fluorescence OM has become crucial for investigating the morphologies and functions of intracellular specimens, this modality is not suitable for imaging optical absorption and requires the use of possibly undesirable exogenous fluorescent molecules for biological samples. Here we demonstrate super-resolution visible photoactivated atomic force microscopy (pAFM), which can sense intrinsic optical absorption with ~8 nm resolution. Thus, the resolution can be improved down to ~8 nm. This system can detect not only the first harmonic response, but also the higher harmonic response using the nonlinear effect. The thermoelastic effects induced by pulsed laser irradiation allow us to obtain visible pAFM images of single gold nanospheres, various nanowires, and biological cells, all with nanoscale resolution. Unlike expensive EM, the visible pAFM system can be simply implemented by adding an optical excitation sub-system to a commercial atomic force microscope.

A new robust variable weighting coefficients diffusion LMS algorithm

We introduce a new robust algorithm that is insensitive to impulsive noise (IN) for distributed estimation problem over adaptive networks. Motivated by the fact that each node can access to multiple spatial data, we propose to discard IN-contaminated data. Under the assumption that IN is successfully detected, we propose a cost function that considers only the uncontaminated data. The derived algorithm is the ATC diffusion LMS algorithm that has variable weighting coefficients depending on IN detection, which leads both to insensitivity to IN and to good estimation performance. A method to detect IN is also presented. Simulation results show that the proposed algorithm has good estimation performance in an environment that is subject to IN, and outperforms the conventional robust algorithms. HighlightsWe propose a new robust algorithm for distributed estimation over adaptive networks.We propose a cost function that considers only the data without impulsive noise.Weighting coefficients that vary depending on impulsive noise occurrence are derived.A method to detect impulsive noise is also presented.The proposed algorithm outperforms the conventional robust algorithms.

Developing ISO 14649-based conversational programming system for multi-channel complex machine tools

A multi-channel complex machine tool (MCCM) is a versatile machining system equipped with more than two spindles and turrets for both turning and milling operations. Despite the potential of such a tool, the value of the hardware is largely dependent on how the machine tools are effectively programmed for machining. In this paper we consider a shop-floor programming system based on ISO 14649 (called e-CAM), the international standard for the interface between computer-aided manufacture (CAM) and computer numerical control (CNC). To be deployed in practical industrial usage a great deal of research has to be carried out. In this paper we present: 1) Design consideration for an e-CAM system, 2) The architecture design of e-CAM, 3) Major algorithms to fulfill the modules defined in the architecture, and 4) Implementation details.