• Journal of the Society of Naval Architects of Korea
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• v.47 no.1
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• pp.76-87
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• 2010

According to the new rules and regulations (New SOLAS), major safety critical systems are to be designed to be redundant, which is called 'Redundancy Design'. This paper was to quantitatively analyze the degree of influence of the redundancy design applied to major safety critical systems using IMO's FSA(formal Safety Assessment) method. For the purpose of this study, the diesel engine system, which is actually one of major safety critical systems, was dealt with FMEA, FTA and ETA technique. In addition, whether the redundancy was met or not was verified and the degree of safety, or redundancy, was represented in terms of reliability. In conclusion, the safety of propulsion systems is possibly assessed systematically by estimating the risk level in terms of frequency and fatality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2864-2870
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• 2014

We suggest various supporting methods for seamless services to support the stable service of system and network. As a representative, the redundancy is the duplication for supporting the stable service of the system and networks. The various redundancy systems have been proposed, these may have a variety forms depending on the number of the service supporting systems. We analyze a availability of a various redundancy model about a redundancy systems. We use a SRN based SPNP as an analysis tool. In this paper, we explain a various redundancy models, then compare and analyze the availability of redundancy models according to a number of service units.

• The Journal of Korea Robotics Society
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• v.3 no.4
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• pp.338-344
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• 2008

Most omni-directional mobile robots have to change their trajectory for avoiding obstacles regardless of the size of the obstacles. However, an omni-directional mobile robot having kinematic redundancy can maintain the trajectory while the robot avoids small obstacles. This works deals with the kinematic modeling and motion planning of an omni-directional mobile robot with kinematic redundancy. This robot consists of three wheel mechanisms. Each wheel mechanism is modeled as having four joints, while only three joints are necessary for creating the omni-directional motion. Thus, each chain has one kinematic redundancy. Two types of wheel mechanisms are compared and its kinematic modeling is introduced. Finally, several motion planning algorithms using the kinematic redundancy are investigated. The usefulness of this robot is shown through experiment.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3104-3110
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• 2011

This paper describes how to ensure safety of train by guaranteeing stable and continuous communication in RF-CBTC. CBTC System uses the wireless communication between onboard and wayside so that safety of wireless communication is the most important. Losing the position of train causes vital problem of train service. By losing the position of train, the other trains are blocked in the block and the train move by emergency mode so headway and safety cannot guaranteed. Therefore, safety is ensured by redundancy of wireless equipment. One of the ways to make redundancy is redundancy of equipment. However, the redundancy of equipment spends a lot of money to avoid interference in limited place like underground. Continuous communication is guaranteed by means of redundancy of wireless communication coverage to solve the problems even though one of the equipment is broken.

• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.308-316
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• 2011

This work deals with development of effective redundancy resolution algorithms for the motion control of manipulator. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the ZMP condition should be taken into account in the manipulator motion in order to guarantee the system stability. In this paper, a new motion planning algorithm for redundant manipulator not fixed to the ground is introduced. A sequential redundancy resolution algorithm is proposed, which ensures the ZMP (Zero Moment Point) stability, the planned operational motion, and additional sub-criteria such as joint limit index. A geometric constraint equation derived by reshaping the existing ZMP equation enables one to employ the sequential redundancy algorithm. The feasibility of the proposed algorithm is verified by simulating a redundant manipulator model.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.157-160
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• 2008

The pursuit of efficiency is taken for granted in today's public administration, and the limit of this study exists in the point that we should carefully deal with combining the redundancy scheme to the public administration. Accordingly, although this study should suggest the specific plans and backgrounds of the needs for the redundancy, it will only find out the applicability of the redundancy to the public administration for its purpose. Redundancy means the excess or superfluity in something, which means the surplusage status ranging from the wasteful and excessive supplies, insignificant additions, to the surplusage in a legal pleading. The emphasis of this study is placed on the changes in the rigidity in believing that the removal of the redundancy from the public administration is the best option in any case of the efficiency. In addition, the necessity of the overlapped organization should not be neglected by the concept of the efficiency. Indeed, it is necessary to correct the overlapped function of superfluity and ambiguity public administration, in order to remove the neglect conflicts between the organizations, to guarantee the inconsistency in the public administration and to ensure the efficiency in the public administration volunteering.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.1-8
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• 2001

Redundancy allocation problems have been considered at single-level systems and it may be the best policy in some specific situations, but not in general. With regards to reliability, it is most effective to allocate the lowest objects, because parallel-series systems are more reliable than series-parallel systems. However, the smaller and lower in the system an object is, the more time and accuracy are needed for duplicating it, and so, the cost can be decreased by using modular redundancy Therefore, providing redundancy at high levels like as modules or subsystems, can be more economical than providing redundancy at low levels or duplicating components. In this paper, the problem in which redundancy is allocated at all level in a series system is addressed, a mixed integer nonlinear programming model is presented and a genetic algorithm is proposed. An example illustrates the procedure.

• Structural Engineering and Mechanics
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• v.59 no.5
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• pp.821-840
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• 2016

A simple design process is proposed for supplemental viscous dampers based on structural safety redundancy. In this process, the safety redundancy of the primary structure without a damper is assessed by the capacity and response spectra. The required damping ratio that should be provided by the supplemental dampers is estimated by taking the structural safety redundancy as a design target. The arrangement of dampers is determined according to the drift distribution obtained by performing pushover analysis. A benchmark model is used to illustrate and verify the validity of this design process. The results show that the structural safety redundancy of the structure provided by the viscous dampers increases to approximately twice that of the structure without a damper and is close to the design target. Compared with the existing design methods, the proposed process can estimate the elastic-plastic response of a structure more easily by using static calculation, and determine the required damping ratio more directly without iterative calculation or graphical process. It can be concluded that the proposed process is simple and effective.

• Computational Structural Engineering : An International Journal
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• v.1 no.2
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• pp.137-137
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• 2001

The reliability/redundancy of structural system has become a serious concern among engineers and researchers after structural failures in Northridge and Kobe earthquakes. The reliability/redundancy factor, ρ, in current codes considers only member force and floor area and has received much criticism from dissatisfied engineers. Within a reliability framework. the redundancy is investigated for dual systems of primary shear walls and secondary moment frames and steel moment frame systems. Probabilistic performance analyses are carried out baled on nonlinear responses under SAC ground motion. The effects of structural configuration, ductilily capacity, 3-D motion, and uncertainty of demand verses capacity are investigated. Important redundancy-contributing factors are identified and a uniform-risk redundancy factor is developed for design. The result are compared with the p factor and its inconsistency is pointed out.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.46-52
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• 2004

A design methodology of the redundancy management for a duplex FBW flight control system is introduced. A statistical analysis is applied to determine two design parameters in CCM(Cross Channel Monitor), threshold and persistence count. An analytic redundancy, which is implemented using a Kalman filtering algorithm is considered. The application of an analytic redundancy to the FCS design of the smart UAV has several advantages of increasing the aircraft's survivability and breaking the tie-condition for a duplex FCS. All the redundancy management algorithms are verified through the numeric simulation for the flight dynamics of the XV-15 tilt rotor.