• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.561-564
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• 2006

Because of new requirements related to the employment of SMT(Surface Mounting Technology) manufacturing and the diversity of components on high density PCB(printed circuit boards), Thermal control of the reflow process is required in oder to achieve acceptable yields and reliability of SMT assemblies. Accurate control of the temperature distribution during the reflow process is one of the major requirements, especially in lead-free assembly. This study has been performed for reflow process using the commercial CFD tool(Fluent) for predicting flow and temperature distributions. There was flow recirculation region that had a weak point in the temperature uniformity. Porous plate was installed to prevent and minimize flow recirculation region for acquiring uniform temperature in oven. This paper provided design concept from CFD results of the steady state temperature distribution and flow field inside a reflow oven.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1118-1125
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• 2010

This paper presents the methods to acquire the Safety Certificate from Independent Safety Assessment based on the IEC standard62279 which is commonly applied to railway system for Automatic Train Control(ATC) system in accordance with Urban Maglev project. This also shows approach methods and relative activities for project life-cycle to accomplish and ensure the system requirements of ATC system, RAMS and S/W quality activities. Furthermore, the key tasks conducted with ISA are noted in detail. These kind of activities for software quality of ATC system to obtain Safety Certificate could be a CASE model to improve the quality of domestic railway system and products, and also contribute to the growth of railway business and toward the achievement of overseas' railway signaling markets.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.629-632
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• 2007

Communications Based Train Control(CBTC) is a continuous, automatic train control system utilizing high-resolution, train location determination independent of track circuits; continuous, high capacity, bi-directional train-to-wayside data communications; and trainborne and wayside processors capable of implementing vital functions. In this paper, we present a basic design of CBTC system based on ERTMS/ETCS specifications. The basic design is composed of system requirements analysis, system functional analysis, system architectural design, sub-system requirements analysis, sub-system functional analysis. Each deliverable has been produced according to a development process based on UML/SysML.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.19-21
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• 2002

Writing requirements in formal notation for a safety-critical system can improve software quality and reduce the errors that may arise later on in the software development life cycle. In this paper, we propose a formal specification approach used to describe the nuclear control system. The approach is based on the existing AECL approach that was the only formal specification technique applied to nuclear control systems in the past. Although the approach is AECL-based, the complex descriptions of certain requirements have been reduced by using different specification techniques. We discuss the differences and how the proposed approach provides not only specification but also verification environment.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.563-572
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• 2004

Maglev is the vehicle which can run in levitated condition by the electro-magnets, and propelled by linear induction motors. Maglev system represents a typical example of large-scale multi-disciplinary system, consisting of subsystems such as train, electrical, hardware, electronics, control, information, communication, civil technology etc., that must be the subject under configuration, control and requirement management. Not only the requirements dictate the contracts with the suppliers but also become the basis of the development process, project execution, system integration, and testing. These requirements provide the basis specification of all development activities.

• ETRI Journal
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• v.18 no.3
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• pp.107-125
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• 1996

In this paper, we define the general requirements of ATM switching systems such as scalability, distributed fashion, and modularity. Also we propose a practical implementation of a scalable ATM switching system whose capacity can be easily expanded. Firstly, the architecture of the system is discussed with an emphasis on system scalability, modularity of subsystems and the simple control network of the design requirements. Secondly, we suggest the three types of distributed call/connection control schemes that are suitable for our switching system. We also estimate their call processing capacity on the average and make a comparison of them under the various system architectures. Since our scalable switching system can be constructed to perform the call processing functions on the various levels of the system capacity, it has much adaptability at the various evolution phases or regions of the network environment.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.47-56
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• 1996

For the implementation of callcontrol software, it will be shown how to divide problems into dimain and also presents methodologies to specify domains according to the object-orented analysis techniques. Domains is specified by the set of related objects as shown in call control examples. Events and conditons are able to be transformed into system invariant so that is possible to figure out the relationship between domains and those concludes that the software requirements specification can be established for the design and implementation. Relationships existing between domains can be formalized so as to verify software requirements.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2070-2074
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• 2008

It is necessary to develop the requirement management system that could trace hazards and manage safety requirements for risk control of railway accident as low as reasonably practicable. In this paper, the requirement management system for control of railway accident risk is introduced. The requirement management system is containing the railway system configuration and safety activity related with identified hazards. The system shall be used to derive safety requirements for risk controland support the traceability of hazards on railway's operation & management. In the future, the system will be applied in the areas such as risk assessment and management, performing safety assurance and revising national regulations etc. for continuous safety improvement in the railway.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.187-187
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• 1998

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.77-77
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• 1998