• Journal of the Korea Safety Management & Science
• /
• v.12 no.2
• /
• pp.65-73
• /
• 2010

In an automated industry PLC plays a central role to control the manufacturing system. Therefore, fault free operation of PLC controlled manufacturing system is essential in order to maximize a firm's productivity. On the contrary, distributed nature of manufacturing system and growing complexity of the PLC programs presented a challenging task of designing a rapid fault finding system for an uninterrupted process operation. Hence, designing an intelligent monitoring, and diagnosis system is needed for smooth functioning of the operation process. In this paper, we propose a method to continuously acquire a stream of PLC signal data from the normal operational PLC-based manufacturing system and to generate diagnosis model from the observed PLC signal data. Consequently, the generated diagnosis model is used for distinguish the possible abnormalities of manufacturing system. To verify the proposed method, we provided a suitable case study of an assembly line.

• Journal of the Korea Safety Management & Science
• /
• v.19 no.4
• /
• pp.183-188
• /
• 2017

Block Chain is a technology that records and shares distributed ledgers without a central authority, providing a decentralized platform for transparent transactions in the business and enhancing transparency and traceability in all transactions to ensure trust in the transaction. Despite initial doubts about this technology, it is committed to adopting, adapting and improving the technology in a wide range of industries, including finance, government, security, logistics, food, medical, legal, and real estate. This study examines this technology, its applicability and potential benefits to the manufacturing supply chain. A tracking system of manufacturing supply chain to visualize transparency and traceability is implemented, and the conditions for adopting the technology in the manufacturing supply chain and the issues to be addressed are discussed.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2001.05a
• /
• pp.96-100
• /
• 2001

본 연구는 자동차 회사를 대상으로 주요 생산공정중 하나인 차체 공장을 대상으로 한 가상플랜트를 설계하고, 이를 구축, 운영함으로써 생산준비의 각 부문에서 사전 검증을 통한 오류 방지, 의사격정의 최적화, 각종 데이터의 관리 및 실제 생산 설비와의 연계를 위한 자동차 Virtual Plant의 모니터링 및 운영 기술에 필요한 기능을 보유한 middle ware s/w 인SysLink Integrator를 활용해 Virtual Plant를 분산 환경에서 구현해 봄으로, 향후 자동차의 가상플랜트 구축에 따른 다양한 응용프로그램과의 통합을 위한, 유용한 하나의 middle wave로 그 활용성을 검토하였다.

• ETRI Journal
• /
• v.46 no.4
• /
• pp.716-726
• /
• 2024

An ultrawide stopband lowpass filter is reported using three stepped impedance resonators with high selectivity. The filter extends the stopband frequency range and attenuation, and two quarter-wave open stubs and three circular ground slots are introduced. The lumped and distributed equivalent models are derived and analyzed. The corresponding results are validated experimentally in a fabricated prototype. The prototype lowpass filter has a 3 dB cutoff frequency (f_c) of 2.9 GHz, and the stopband is extended up to 35 GHz (12.07f_c), with an attenuation level better than 20 dB throughout. The passband-to-stopband transition (3 dB-20 dB) bandwidth is 0.18 GHz, and the roll-off factor is 135 dB/GHz at 30 dB. The insertion loss is 0.3 dB at 1.6 GHz. The normalized circuit size of the proposed filter with respect to the guided wavelength is 0.04.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.2
• /
• pp.211-215
• /
• 2010

Continuous contraction and expansion of disk brake can be due to friction and temperature difference at repeated sudden braking. As serious vibration at disk is produced, the braking force will be changed ununiformly and braking system can not be stabilized. Temperature and heat flux at disk brake are investigated by structural and thermal analysis in this study. The maximum equivalent stress and displacement are shown respectively at the ventilated hole and the lower part of disk plate. At thermal analysis of initial state, temperature on disk plate is distributed from $95.9^{\circ}C$ to $100^{\circ}C$. The maximum heat flux of $0.0168W/mm^2$ is shown at the inner friction part between disk plate and pad. At thermal analysis of transient state, temperature on disk plate is distributed from $95^{\circ}C$ to $96.5^{\circ}C$ after 100 second. The maximum heat flux of $0.0024W/mm^2$ is also shown at the inner friction part between disk plate and pad. By comparing with initial state, the temperature on disk plate is more uniformly distributed and heat flux is more decreased by 7 times at transient state.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2002.05a
• /
• pp.285-292
• /
• 2002

A cluster tool for semiconductor manufacturing is an integrated device that consists of several single wafer processing modules and a wafer transport module based on a robot. The distributed module controllers are integrated by an inter-module communication network and coordinated by a centralized controller, called a cluster tool controller (CTC). Since the CTC monitors and coordinates the distributed complex module controllers for advanced process control, complex commuication messaging and services between the CTC and the module controllers are required. A SEMI standard, CTMC(Cluster Tool Module Communication), specifies application-level communication service requirements for inter-module communication. We propose the use of high-level fieldbuses, for instance. PROFIBUS-FMS, for implementing CTMC since the high-level fieldbuses are well suited for complex real-time distributed manufacturing control applications. We present a way of implementing CTMC using PROFIBUS-FMS as the communication enabler. We first propose improvements of a key object of CTMC for material transfer and the part transfer protocol to meet the functional requirements of modem advanced cluster tools. We also discuss mapping objects and services of CTMC to PROFIBUS-FMS communication objects and services. Finally, we explain how to implement the mappings.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.1
• /
• pp.89-95
• /
• 2006

Planning distributed manufacturing logistics is one of main issues in supply chain management. This paper proposes a hybrid heuristic approach for the Multi-Level, multi-item Capacitated Lot Sizing Problem (MLCLSP) in supply chain network. MLCLSP corresponds to a mixed integer programming (MIP) problem. With integer variable solutions determined by heuristic search, this MIP problem becomes linear program (LP). By repeatedly solving the relaxed MIP problems with a heuristic search method in a hybrid manner, this proposed approach allocates finite manufacturing resources fur each distributed facilities and generates feasible production plans. Meta heuristic search algorithm is presented to solve the MIP problems. The experimental test evaluates the computational performance under a variety of problem scenarios.

• Journal of information and communication convergence engineering
• /
• v.8 no.5
• /
• pp.473-478
• /
• 2010

Today's engineering design is carried out in a distributed fashion geographically or physically. This places new requirements on the computational environments such as efficient integration and collaboration. With the advances of the Internet and Network environment recently, many researches have been proposed and at the same time, Web-based distributed design gives to a new paradigm in design and manufacturing fields. That is, Web-based technologies lead to reduce the product development times and to ensure a competitive product in order to exchange and interact of real-time design information that integrates the distributed design environment between departments as well as companies via Internet and Web. So, an efficient data communication for design information sharing is the foundation for collaborative systems in the distributed environment. Design data communication techniques such as CORBA, DCOM and RMI have been considered in the existing research but they have some problems that are limitations of interoperability and firewall problems in the Web. Therefore, this paper presents a Web-based distributed design application where distributed design information resources are integrated and exchanged using Web Services for supporting XML and HTTP without the interoperability and firewall problems through the 330K VLCC case.

• Journal of Korean Society for Quality Management
• /
• v.50 no.4
• /
• pp.717-734
• /
• 2022

Purpose: The purpose of this study is to effectively detect violations that occur simultaneously against Good Manufacturing Practice, which were concealed by drug manufacturers. Methods: In this study, we present an analysis framework for analyzing regulatory violation patterns using Association Rule Mining (ARM), Text Mining, and t-distributed Stochastic Neighbor Embedding (t-SNE) to increase the effectiveness of on-site inspection. Results: A number of simultaneous violation patterns was discovered by applying Association Rule Mining to FDA's inspection data collected from October 2008 to February 2022. Among them there were 'concurrent violation patterns' derived from similar regulatory ranges of two or more regulations. These patterns do not help to predict violations that simultaneously appear but belong to different regulations. Those unnecessary patterns were excluded by applying t-SNE based on text-mining. Conclusion: Our proposed approach enables the recognition of simultaneous violation patterns during the on-site inspection. It is expected to decrease the detection time by increasing the likelihood of finding intentionally concealed violations.

• KIPS Transactions on Computer and Communication Systems
• /
• v.8 no.2
• /
• pp.41-56
• /
• 2019

Cloud manufacturing is a new concept of manufacturing process that works like a single factory with connected multiple factories. The cloud manufacturing system is a kind of large-scale CPS that produces products through the collaboration of distributed manufacturing facilities based on technologies such as cloud computing, IoT, and virtualization. It utilizes diverse and distributed facilities based on centralized information systems, which allows flexible composition user-centric and service-oriented large-scale systems. However, the cloud manufacturing system is composed of a large number of highly heterogeneous subsystems. It has difficulties in interconnection, data exchange, information processing, and system verification for system construction. In this paper, we derive the user requirements of various aspects of the cloud manufacturing system, such as functional, human, trustworthiness, timing, data and composition, based on the CPS Framework, which is the analysis methodology for CPS. Next, by analyzing the user requirements we define the system requirements including scalability, composability, interactivity, dependability, timing, interoperability and intelligence. We map the defined CPS system requirements to the requirements of oneM2M, which is the platform standard for IoT, so that the support of the system requirements at the level of the IoT platform is verified through Mobius, which is the implementation of oneM2M standard. Analyzing the verification result, finally, we propose a large-scale cloud manufacturing platform based on oneM2M that can meet the cloud manufacturing requirements to support the overall features of the Cloud Manufacturing CPS with dependability.