• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3335-3339
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• 2013

Boron-doped ZnO (BZO) nanorods were grown on quartz substrates using hydrothermal synthesis, and the temperature-dependence of their photoluminescence (PL) was measured in order to investigate the origins of their PL properties. In the UV range, near-band-edge emission (NBE) was observed from 3.1 to 3.4 eV; this was attributed to various transitions including recombination of free excitons and their longitudinal optical (LO) phonon replicas, and donor-acceptor pair (DAP) recombination, depending on the local lattice configuration and the presence of defects. At a temperature of 12 K, the NBE produces seven peaks at 3.386, 3.368, 3.337, 3.296, 3.258, 3.184, and 3.106 eV. These peaks are, respectively, assigned to free excitons (FX), neutral-donor bound excitons ($D^{\circ}X$), and the first LO phonon replicas of $D^{\circ}X$, DAP, DAP-1LO, DAP-2LO, and DAP-3LO. The peak position of the FX and DAP were also fitted to Varshni's empirical formula for the variation in the band gap energy with temperature. The activation energy of FX was about ~70 meV, while that of DAP was about ~38 meV. We also discuss the low temperature PL near 2.251 eV, related to structural defects.

• The Journal of Society for e-Business Studies
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• v.12 no.1
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• pp.1-24
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• 2007

In the mold parts industry, customers typically place orders for order-made parts with some changes to the design specifications of ready-made parts within the extent of the manufacturing capability of the supplier. Being customized for ready-made parts, existing e-Catalog systems cannot support the above trade pattern. To solve this problem, an ETO (engineering-to-order) method is proposed here, enabling the trade of order-made parts in an e-Catalog system by utilizing the design and manufacturing knowledge of the part suppliers. After addressing technological challenges and solutions, we briefly describe application of the ETO method to two types of mold parts - ejector pins and mold bases.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.17-24
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• 2015

Smart factory requires 4 Zero factors including Zero Waiting-time, Zero Inventory, Zero Defect, Zero Down-time) that needs IT convergence for production resources of 4M1E(Man, Machine, Material, Method, Energy) in real time and event processing in all type of manufacturing enterprises. This paper will be explaining about core emerging production IT convergence technologies including cyber device security, 4M1E integration, real time event driven architecture, common platform of manufacturing standard applications, smart factory to-be model for small and medium manufacturing enterprises.

• Proceedings of the Korea Society for Simulation Conference
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• 1996.05a
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• pp.15-15
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• 1996

A shop floor control system (SFCS) is the central part of a CIM system used to control the activities of several pieces of manufacturing equipment (e.g., NC machines, robots, conveyors, AGVs, AS/RS). The SFCS receives orders and related process plans, and then performs selecting a specific process routing, allocating resources, scheduling the workpieces, downloading the processing instructions (e.g., RS-274 instructions for NC machines, VAL II programs for robot), monitoring the progress of activities, detecting and recovering from errors, and preparing reports on the status of the manufacturing system. Simulation has been utilized in discovering control policies used for resolving shop floor be control problems such as resource contentions, part dispatching, deadlock. The simulation model must be designed to respond to real-time data coming from a shop floor. However, to rapidly build a realtime simulation model of SFCS cannot be easily accomplished. This talk is to address an automatic program generator of discrete event simulation model for shop floor control from process plans and resource models. The program generator is capable of constructing complete discrete simulation models for multi-product and multi-stage flexible manufacturing systems.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.2
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• pp.193-198
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• 2004

This is the dissertation of the study of design characteristics about the practical flexible manufacturing system (PFMS). The basic ideas to analyze the manufacturing system which is the automatically operated is dependant on the various manufacturing procedures in factory. PFMS is the very useful equipment for students and trainee of production lines. This system is composed of hardware and software sub systems i.e. control and test unit and personal computer with software. The PFMS can be developed with design concepts and approved the capability of first article with functional tests. The PFMS module will be very useful for the manufacturing drill system in universities and practical fields. The flexible manufacturing systems have various subsystems appropriated for the final manufacturing products. Therefore the systems have the various kinds of hard wares as well as softwares. We study the software for the practical flexible manufacturing system designed in the Halla University and specially the design concept and using specification of the SCARA (Selective Compliance Assembly Robot Arm) robot which is used for the movement of the product is analyzed and introduced in this dissertation.

• Advances in robotics research
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• v.2 no.3
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• pp.237-245
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• 2018

This study evaluates the efficacy of a class robust control scheme namely active force control in performing a joint based trajectory tracking of an upper limb exoskeleton in rehabilitating the elbow joint. The plant of the exoskeleton system is obtained via system identification method whilst the PD gains were tuned heuristically. The estimated inertial parameter that enables the AFC disturbance rejection effect is attained by means of a non-nature based metaheuristic optimisation technique known as simulated Kalman filter (SKF). It was demonstrated from the present investigation that the proposed PDAFC scheme outperformed the classical PD algorithm in tracking the prescribed trajectory both in the presence and without the presence of disturbance attributed by the mannequin limb weights (1 kg and 1.5 kg) that mimics the weight of actual human limb weight. Therefore, it is apparent from the results obtained from the present study that the proposed control scheme, i.e., PDAFC is suitable for the application of exoskeleton for stroke rehabilitation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.4
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• pp.1-8
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• 2003

It is well known that design cost is only about 5% of final product cost but over 70% of it is determined during design stage. Earlier in the product design and development cycle the design changes occur, more economic they become. Therefore, it is recommended that the manufacturing time and cost of product are considered in steps involved in designing and manufacturing a product as early as possible. In this study, it is proposed a possible way that cm be available for estimating manufacturing time of parts, which are manufactured by conventional material removal processes (e.g. turning, milling and drilling). For it to be useful in the early design stage, the minimum number of informations on dimension shape, and design features of part will be used in this method.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.49-52
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• 1996

In this article, we develop a 'dynamic' approach to manufacturing improvement, based on perspectives of manufacturing learning and decision theory. First, we present an alternative definition of production system consistent with a decision-theoretic perspective: the system consists of structural, infra-structural, and decision making constructs. A primary proposition is that learning capability possessed by a manufacturing system be prerequisite for the system to improve its manufacturing performance through optimal controlling of the three constructs. To support the proposition, we elaborate on a mathematical representation of "learning" as defined in an applied setting. We show how the learning capability acts as an integrating force ameliorating the trade-off between two key manufacturing capabilities, i.e., process controllability and process flexibility.exibility.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.669-670
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.425-426
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• 2007