• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1699-1702
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• 2007

We will discuss encapsulation of OLEDs on both flexible and rigid glass substrates. Accelerated testing at 6CC/90RH and 85C/85RH is compared and acceleration factors for OLED and Calcium test samples are discussed.We have tested the stability and performance of our barrier coating to much higher temperatures: up to 140 C. Water Vapor Transmission rates at temperatures from 60 to 140 C are presented. Rates and methods for low cost manufacturing on a large scale are analysed

• Journal of the Korean Data and Information Science Society
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• 제28권6호
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• pp.1301-1311
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• 2017

제조 빅데이터 시스템은 제조 전 공정에서 관련된 4M 데이터의 수집, 저장, 관리, 예측적 분석을 통해 선제적 제조 활동 개선이 가능한 의사결정을 지원하고 있다. 이러한 시스템에서 데이터의 효율적인 관리와 운영을 위해 데이터를 효과적으로 시각화하는 것이 무엇보다도 중요하다. 본 논문에서는 제조 빅데이터 시스템에서 데이터 수집, 분석 및 예측 결과를 효과적으로 보여 주기 위해 사용가능한 시각화 기법을 제시한다. 본 논문에서 제시된 시각화 기법을 통해 제조 현장에서 발생하는 문제를 보다 손쉽게 파악할 수 있었을 뿐만 아니라 이들 문제를 효과적으로 대응할 수 있어 매우 유용하게 사용될 수 있음을 확인하였다.

• 한국광학회지
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• 제18권6호
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• pp.395-400
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• 2007

본 연구는 지문 인식 시스템 중에서 프리즘을 이용한 광학계의 설계에 대한 것이다. 이는 프리즘, 렌즈, 그리고 CMOS 이미지 센서(혹은 CCD) 등으로 구성되어 있는 광학계이다. 종래의 프리즘을 이용한 지문인식 광학계에서는 지문에 물이 묻어 있는 경우에 영상의 품질이 현저히 저하되는 문제점이 있다. 이 경우에 프리즘의 굴절률을 높임으로써 영상의 품질을 충분히 높일 수 있었다. 또한 프리즘과 렌즈를 사용함으로 인하여 발생하는 비대칭 축소 왜곡(anamorphic distortion)과 상면의 지를 최소화되는 프리즘 꼭지각 $\alpha$를 제안한다.

• 한국표면공학회지
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• 제43권3호
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• pp.121-126
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• 2010

The PS(porous Si) were fabricated with different anodization time and current density. The structural and optical properties of PS were investigated by SEM(scanning electron microscopy), AFM(atomic force microscopy), and PL(photoluminescence). It is found that the pore size and surface roughness of PS are proportional to the current density. The PL spectra show that the PL peak position is red-shifted with increasing anodization time. This behavior corresponds to the change of pore size which is consistent with the quantum confinement model. The FWHM(full width at half maximum) of PL peak is decreased from 97 to 51 nm and the PL peak position is blue-shifted with increasing current density up to 10 mA/$cm^2$. The PL peak intensity of the PS fabricated under 1 mA/$cm^2$ is the highest among samples.

• 산업경영시스템학회지
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• 제43권1호
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• pp.143-150
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• 2020

To enhance the effectiveness of the FMS (flexible manufacturing system), it is necessary for the manufacturing control system to be upgraded by integrating the cyber and the physical manufacturing systems. Using the CPPS (Cyber-Physical Production System) concept, this study proposes a 4-stage vertical integration and control framework for an aircraft parts manufacturing plant. In the proposed framework, the process controller prepares the operations schedule for processing work orders generated from the APS (advanced planning & scheduling) system. The scheduled operations and the related control commands are assigned to equipments by the dispatcher of the line controller. The line monitor is responsible for monitoring the overall status of the FMS including work orders and equipments. Finally the process monitor uses the simulation model to check the performance of the production plan using real time plant status data. The W-FMCS (Wing rib-Flexible Manufacturing Control & Simulation) are developed to implement the proposed 4-stage CPPS based FMS control architecture. The effectiveness of the proposed control architecture is examined by the real plant's operational data such as utilization and throughput. The performance improvement examined shows the usefulness of the framework in managing the smart factory's operation by providing a practical approach to integrate cyber and physical production systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.555-560
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• 2002

This paper addresses the methodologies for manufacturing systems design. While a number of design methods are used in product or part design, methods for manufacturing systems design are rarely known. Two approaches, simulation and axiomatic design theory, are discussed with respective case examples. The usual purpose of using simulation is to identify the bottleneck of a manufacturing system or to evaluate its performance with the aim of configuring the manufacturing system. The simulation typically proceeds in steps such as problem definition, model building, numerical experimentation, analysis and evaluation. The axiomatic design method transforms customer attributes into functional requirements and repeats mapping processes between functional domain and physical one until a satisfactory level of refinement of the functional requirements and the design parameters is reached. Possible design alternatives are evaluated by applying the independence axiom as well as the information axiom.

• 산업경영시스템학회지
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• 제31권4호
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• pp.168-176
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• 2008

In an environment where manufacturing conditions such as product lines keep changing, manufacturing control systems need to be continually maintained and upgraded according to the change. This requires an effective system implementation methodology. In this paper, a methodology based on the multi-criteria similarity comparison of manufacturing processes is proposed. A newly introduced process is compared with existing ones based on the multi-criteria similarity, and candidates for software reuse are selected from stored modules according to the overall process characteristics. The proposed methodology has been tested for an electronics manufacturing company's manufacturing control system, and the result has been satisfactory in that it can save time and efforts for system implementation.

• 산업경영시스템학회지
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• 제37권2호
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• pp.55-61
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• 2014

Recently, the manufacturing system is being changed in a mass customization and small quantity batch production. MES is a powerful production management tool supporting production optimization from the process initiation to the final shipment. It is a production management system which plans and executes based on the production data in the shop floor. This study deployed the utilization of production data and web HMI system to process real-time production data through the collection with the shop floor. The developed system was applied to the equipment operating time and other production data could be processed with the real-time. The proposed system and web HMI can be applied for various production systems by using different logic.

• Journal of applied mathematics & informatics
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• 제33권1_2호
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• pp.77-87
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• 2015

Parallel lines are often used to increase production rate in many manufacturing systems where the main line splits into several lines in parallel, and after some operations, they merge into a main line again. Queueing networks with finite buffers have been widely used for modeling and analyzing manufacturing systems. This paper provides an approximation technique for multi-server two-stage networks with merge configuration and blocking which will be a building block for analysis of general manufacturing systems with parallel lines and merge configuration. The main idea of the method is to decompose the original system into subsystems that have two service stations with multiple servers, two buffers and external arrivals to the second stage are allowed. The subsystems are modeled by level dependent quasi-birth-and-death (LDQBD) process.

• 한국정밀공학회지
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• 제30권2호
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• pp.194-205
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• 2013

In recent years, the main concerns of enterprise management activities is how to strengthen the competitiveness to quickly respond to changes and sustain the growth in business environment. In order to achieve competitiveness and sustainability, a large variety of production informatization systems, such as MES (Manufacturing Execution System), ERP (Enterprise Resource Planning), have been introduced to manufacturing companies. However, there have been many problems owing to the reckless introduction of those systems. Therefore, it is necessary to evaluate the informatization level of the manufacturing company before introducing production informatization systems. This paper presents methodology and system to evaluate the informatization level of manufacturing company. The proposed evaluation method, based on the traditional questionnaire approaches, considers the various characteristics of the company. And then, we proposed models for calculation and production informatization level using 450 results of conducting a survey. Finally, a web-based system was developed for the evaluation of informatization level.