• 산업경영시스템학회지
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• 제22권52호
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• pp.285-295
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• 1999

Developing control functions that operate and cooperate each equipment in order to achieve a goal is one of the most important problems in the installation of automated manufacturing systems. This paper discusses the development of a control system for heterarchical architecture and a simulator to verify operations of the control system. The object-oriented paradigm that has excellent reusability, portability, and extensibility is currently being used in many application fields as a software development methodology. Especially, UML(Unified Modeling Language), the third generation object-oriented modeling methodology, has advantages such as model generalization, clearness, and so on. In this research, software objects to accomodate the real time environments of automated manufacturing systems are modeled with the diagrams of UML. Based on these models, control software is developed as a format of pseudo-codes. A simulator is implemented to validate the developed control system.

• 산업경영시스템학회지
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• 제34권4호
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• pp.57-65
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• 2011

Monitoring auto correlated processes is prevalent in recent manufacturing environments. As a proactive control for manufacturing processes is emphasized especially in the semiconductor industry, it is natural to monitor real-time status of equipment through sensor rather than resultant output status of the processes. Equipment's sensor data show various forms of correlation features. Among them, considerable amount of sensor data, statistically autocorrelated, is well represented by Box-Jenkins autoregressive moving average (ARMA) model. In this paper, we present a design method of statistical process control (SPC) used for monitoring processes represented by the ARMA model. The proposed method shows benefits in the power of detecting process changes, and considers robustness to ARMA modeling errors simultaneously. We prove benefits through Monte carlo simulation-based investigations.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 추계학술발표대회
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• pp.300-303
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• 2007

사용자의 행동을 모니터링 하는 것에 대한 이전의 기술적인 연구는 네트워크 트래픽과 데이터 베이스 접근 패턴에 집중되어 있으나 이러한 접근은 사용자간의 데이터를 교환하고 공유하는 등의 상호 작용을 관찰하기에는 부족하다. 따라서 'BHave' 라는 가상 환경에서 사용자의 행동을 추적할 수 있는 시스템을 개발하여 문서에 접근하는 사용자의 행동을 모니터링한다. 서버쪽의 데이터베이스에서 데이터를 가져와서 클라이언트의 API 를 통하여 사용자가 선택한 데이터를 분석한 뒤 사용자에게 그래프를 통해서 시각적으로 분석 결과를 보여준다.

• 한국생산제조학회지
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• 제23권3호
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• pp.243-249
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• 2014

Currently, CFRP composites are rapidly replacing steel plates, as they are lighter, stronger, and more elastic; however, they are poorly suited to hygrothermal and impact-collapsed environments because moisture can alter their molecule arrangement and chemical properties. In this study, environments are experimentally simulated in order to investigate changes in the moisture absorption inside a CFRP composite and to determine its weakest point. Moreover, changes in the moisture absorption ratio at temperatures of $60^{\circ}C$ and $80^{\circ}C$ are studied and compared in order to understand how changes in temperature affect moisture absorption inside CFRP composites. Results show that moisture absorption leads to a strength reduction of around 50%. In addition, the moisture absorption rate inside CFRP composites is shown to change rapidly with increasing temperature. Accordingly, it showed that the change in matrix also has a weak point.

• 한국기계가공학회지
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• 제19권4호
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• pp.85-92
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• 2020

Applications for the unmanned aerial vehicle (UAV) have expanded enormously in recent years. Of all its various technologies, the UAV's ability to take off and land in a moving environment is particularly required for military or oceanic usage. In this study, we develop a novel leveling platform that allows the UAV to stably take off and land even on uneven terrains or in moving environments. The leveling platform is composed of an upper pad and a lower mobile base. The upper pad, from which the UAV can take off or land, is designed in the form of a 2 degrees of freedom (DOF) gimbal mechanism that generates the leveling function. The lower mobile base has a four-wheel drive structure that can be operated remotely. We evaluate the developed leveling platform by performing extensive experiments on both the horizontal terrain and the 5-degree ramped terrain, and confirm that the leveling platform successfully maintains the horizontal pose on both terrains. This allows the UAV to stably take off and land in moving environments.

• 산업공학
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• 제25권2호
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• pp.264-275
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• 2012

The process of semiconductor(IC Package) manufacturing usually includes lots of complex and sequential processes. Many kinds of equipments are installed with the mixed concept of serial and parallel manufacturing system. The business environments of the semiconductor industry have been changed frequently, because new technologies are developed continuously. It is the main reason of new investment plan and layout consideration. However, it is difficult to change the layout after installation, because the major equipments are expensive and difficult to move. Furthermore, it is usually a multiple-objective problem. Thus, new investment or layout change should be carefully considered when the production environments likewise product mix and production quantity are changed. This paper introduces a simulation case study of a Korean company that produces packaging substrates(especially lead frames) and requires multi-objective decision support. $QUEST^{(R)}$ is used for simulation modelling and AHP(Analytic Hierarchy Process) and DEA(Data Envelopment Analysis) are used for weighting of qualitative performance measures and solving multiple-objective layout problem, respectively.

• 산업경영시스템학회지
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• 제47권2호
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• pp.116-123
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• 2024

In the manufacturing industry, dispatching systems play a crucial role in enhancing production efficiency and optimizing production volume. However, in dynamic production environments, conventional static dispatching methods struggle to adapt to various environmental conditions and constraints, leading to problems such as reduced production volume, delays, and resource wastage. Therefore, there is a need for dynamic dispatching methods that can quickly adapt to changes in the environment. In this study, we aim to develop an agent-based model that considers dynamic situations through interaction between agents. Additionally, we intend to utilize the Q-learning algorithm, which possesses the characteristics of temporal difference (TD) learning, to automatically update and adapt to dynamic situations. This means that Q-learning can effectively consider dynamic environments by sensitively responding to changes in the state space and selecting optimal dispatching rules accordingly. The state space includes information such as inventory and work-in-process levels, order fulfilment status, and machine status, which are used to select the optimal dispatching rules. Furthermore, we aim to minimize total tardiness and the number of setup changes using reinforcement learning. Finally, we will develop a dynamic dispatching system using Q-learning and compare its performance with conventional static dispatching methods.

• 한국항행학회논문지
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• 제27권5호
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• pp.594-609
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• 2023

이 연구는 블록체인 기반 5G세라믹 안테나 제조(B-5GAM) 아키텍처를 활용하여 5G세라믹 안테나 제조 공정의 복잡성을 해결하기 위한 새로운 접근 방식을 소개한다. 이 아키텍처는 블록체인 기술과 스마트 컨트랙트를 원활하게 통합하여 5G세라믹 안테나 제조 영역에서 투명성, 보안성, 효율성을 향상시켰다. 블록체인을 적용하여 보안 조치, 프로세스 효율성 및 전반적인 신뢰성을 향상시킴으로써 생산 프로세스를 최적화할 뿐만 아니라 향후 통신 기술 발전을 위한 견고한 기반을 구축하는 효과는 분명하다. 5G 안테나를 제조하고 블록체인 및 스마트컨트랙트를 적용하기 위한 알고리즘 제시를 통해 B-5GAM 아키텍처를 검증하고 실제 제조 환경에서의 적용 가능성을 확인하였다. 이 연구 결과는 5G세라믹 안테나 제조 분야에서 블록체인과 스마트 컨트랙트의 활용 가능성을 입증하여 제조 효율성과 신뢰성을 향상시킬 수 있음을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2676-2681
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• 2003

The Haptic Exploration Laboratory at The Johns Hopkins University is currently exploring many problems related to haptics (force and tactile information) in human-machine systems. We divide our work into two main areas: virtual environments and robot-assisted manipulation systems. Our interest in virtual environments focuses on reality-based modeling, in which measurements of the static and dynamic properties of actual objects are taken in order to produce realistic virtual environments. Thus, we must develop methods for acquiring data from real objects and populating pre-defined models. We also seek to create systems that can provide active manipulation assistance to the operator through haptic, visual, and audio cues. These systems may be teleoperated systems, which allow human users to operate in environments that would normally be inaccessible due to hazards, distance, or scale. Alternatively, cooperative manipulation systems allow a user and a robot to share a tool, allowing the user to guide or override the robot directly if necessary. Haptics in human-machine systems can have many applications, such as undersea and space operations, training for pilots and surgeons, and manufacturing. We focus much of our work on medical applications.

• Corrosion Science and Technology
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• 제7권3호
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• pp.145-151
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• 2008

Material degradation such as high temperature oxidation of metallic material is a severe problem in energy generation systems or manufacturing industries. The metallic materials are oxidized to form oxide films in high temperature environments. The oxide films act as diffusion barriers of oxygen and metal ions and thereafter decrease oxidation rates of metals. The metal oxidation is, however, accelerated by mechanical fracture and spalling of the oxide films caused by thermal stresses by repetition of temperature change, vibration and by the impact of solid particles. It is therefore very important to investigate mechanical properties and adhesion of oxide films in high temperature environments, as well as the properties in a room temperature environment. The oxidation tests were conducted for Ni and Ni-Co alloy under high temperature corrosive environments. The hardness distributions against the indentation depth from the top surface were examined at room temperature. Dynamic indentation tests were performed on Ni oxide films formed on Ni surfaces at room and high temperature to observe fractures or cracks generated around impact craters. As a result, it was found that the mechanical property as hardness of the oxide films were different between Ni and Ni-Co alloy, and between room and high temperatures, and that the adhesion of Ni oxide films was relatively stronger than that of Co oxide films.