• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3685-3691
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• 2015

We developed the platform safety step system for the passenger to avoid misstep accident and secure the pedestrian safety. In this study, we classify platform safety step system into hierarchy system and predict the failure rate of each part and calculate the failure rate & MTBF(Mean Time Between Failure) of each module(sub-system) by means of RBD(Reliability Block Diagram) & FTA(Fault Tree Analysis). Finally, we will propose the reliability analysis results for RAMS analysis of platform safety step system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.3
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• pp.657-673
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• 2019

As various IT and OT systems such as Electronic Chart Display and Information System and Automatic Identification System are used for ships, security elements that take into account even the ship's construction and navigation environment are required. However, cyber security research on the ship and shipbuilding ICT equipment industries is still lacking, and there is a lack of systematic methodologies through threat modeling. In this paper, the Data Flow Diagram was established in consideration of stakeholders approaching the ship system. Based on the Attack Library, which collects the security vulnerabilities and cases of ship systems, STRIDE methodologies and threat modeling using the Attack Tree are designed to identify possible threats from ships and to present ship cyber security measures.

• Journal of the Korean Society of Systems Engineering
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• v.10 no.1
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• pp.73-80
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• 2014

Designing test case flows for water crossing operation of a wheeled vehicle is a new attempt for which very limited experiences exist. In this paper, a Function Flow Block Diagram(FFBD) and a Classification Tree Method(CTM) were combined to see if this method is viable to generate the test case flows at the functional analysis stage. It was found that this method can be practically used for the very complicated test case generation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.1-8
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• 1997

A wide class of networking application services, such as video teleconferencing, VOD, LAN bridging, and distributed data processing require multipoint communications. The essential component inteh network to achieve this is a multicast packet switch which is capable of packet replication and switching. In this paper, we propose an efficient mukticast addressing scheme using the smallest number of routing bits which is deterministic lower bound. The new scheme performs all point-to-multipoint connection in radix-2 tree ATM switch like banyan network. Also, we provide a simple radix-2 switch block diagram for achieving our algorithm. And we investigate several addressing schemes for implementing multicasting in radix-r tree ATM switch and evaluate several performance factors, such as complexity of the additional header bits, requirement of the internal speedup and complexity of the major hardware.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.50-56
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• 2003

In the development of complex software system, it is important to use hierarchical use case model due to the complex scope of development procedure. The use case model is core factor of the OMG (Object Management Group)'s UML (Unified Modeling Language) diagrams. In this paper, we propose a novel method to check syntactic consistency automatically in use case models at the different level of abstraction. This method is a rule-based approach which utilizes actor tree, use case tree and use case description. The proposed method is simulated on ITS (Intelligent Transportation System) architecture for the verification.

• Journal of Plant Biology
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• v.27 no.2
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• pp.51-60
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• 1984

Jisimdo is an island where evergreen broadleaved forests are well preserved. Soil environments and forest structures of Jisimdo were investigated, and an actual vegetation map and profile diagrams were drawn out. The natural vegetation of Jisimdo was divided into two stand units, one was evergreen broadleaved forest and the other was Pinus thunbergii forest. 26 species were identified as evergreen broadoeaved trees, and among them, Camellia japonica was the dominont of the tree layer of evergreen broadleaved forest. Profile diagram shows that Camellia japonica, with average height of 7∼8m, formed lower tree layer, and laurels like Cinnamomum japonicum, Machilus thunbergii, and Neolitsea sericea formed upper tree layer. In Pinus thunbergii forest, plants of shrub and herb layers were abundant because of much light penetrated into the forest floor, and these layers were largely composed of evergreen broadleaved trees. This fact shows the possibility of succession from Pinus thunbergii forest into evergreen broadleaved forest. Jisimdo is geographically adjacent to Jangseungpo and Okpo, and this increases the economic value of Jisimdo as a place of public resort. It will be necessary from being destroyed by land development and human interferences.

• Journal of the Korea Safety Management & Science
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• v.17 no.2
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• pp.215-228
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• 2015

A creative innovation and an innovative problem-solving of industrial companies can be achieved by overcoming the challenges of technical and physical contradictions. The approaches to address conflicting and paradoxical problems, such as technical and physical contradictions have a crucial role in advancing the quality assessment for manufacturer and service provider. The term, technical contradiction, depicts the state that improvement of one ends of IFR (Ideal Final Result) leads to unfavorable condition of the other ends, and results in conflicting problem. Another type of contradictions that's discussed in this study is a physical contradiction which is due to two mutually opposing states of the means of ends, and gives paradoxical situation. By integrating the means-ends chain perspectives, the physical contradiction that is a specifically root-causes, "means", can be initially addressed to resolve the downstream problem of technical contradiction which represents a general and abstract goals, "ends". This research suggests IFR resolution processes to handle both physical contradiction of means and technical contradiction of ends by employing causal relationship with IFR, effects and causes. In summary, the study represents three major processes that resolve such contradictions are demonstrated as follows: 1) Derivation of causal and hierarchical relationship among IFR, ends and means by considering CAED (Cause-And-Effect Diagram) and LT (Logic Tree). 2) Identification of causal relationship between physical contradiction and technical contradiction by using TPCT (TRIZ Physical Contradiction Tree) and TCD (Technical Contradiction Diagram). 3) Application of integrated TRIZ principles by classifying 40 inventive principles into 4 general conditions of the separation principle of mutually opposite states in space, in time, based on conditions, and between the parts and the whole. In order to validate the proof of proposed IFR resolution processes, the analysis of the TRIZ case studies from National Quality Circle Contest in the years, 2011 to 2014 have been proposed. The suggested guidelines that are built based on TRIZ principles can uniquely enhance the process of quality innovation and assessment for quality practitioners.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.9
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• pp.39-45
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• 2004

A design method is proposed for the sequence detection with fixed decision delay with less hardware complexity using the concept of the Voronoi diagram and its dual, the Delaunay tessellation. This detector design is based on the Fixed Delay Tree Search (FDTS) detection. The FDTS is a computationally efficient sequence detection algerian and has been shown to achieve near-optimal performance in the severe Intersymbol Interference (ISI) channels when combined with decision feedback equalization and the appropriate channel coding. In this approach, utilizing the information contained in the Voronoi diagram or equivalently the Delaunay tessellation, the relative location of the detector input sequence in the multi-dimensional Euclidean space is found without any computational redundancy, which leads to a reduced complexity implementation of the detector.

• Journal of the Korean Society of Safety
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• v.3 no.2
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• pp.5-16
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• 1988

This study is conducted to evaluate the explosion of tolune storage tank in the petrochemical plant by Fault Tree Analysis. The conclusions are as follows; 1) Fault Tree diagram and the required computer program for evaluation of explosion accident is developed. 2) The probability of the top event, explosion accident, is $1.5\;{\times}\;10^{-8}$ per year, so there is almost no possibility of explosion during the life cycle of tank. However, the probability of Gate 6 and Gate 7 is 8.8 per month, therefore, attention should be paid to them for accident prevention. 3) The number of minimal cut sets is 67 sets which are not calculated the probability of each set, because of the lack of computer capacity. All the minimal cut sets should be examined case by case. However, it is necessary to be paid attention to COM1, 126, 131, and COM4 in minimal cut sets, because the number of appearance is so high. 4) The number path sets is 70 sets which are not calculated the probability of each set, because of the lack of computer capacity. It is very useful to prepare safety checklist by using this minimal path sets. Also, the events which appear many times, 123, COM5, 139, 127 and 128, are very high in reliability.

• Journal of Korea Multimedia Society
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• v.18 no.11
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• pp.1281-1288
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• 2015

Nongroup Cellular Automata(CA) having two trees in the state transition diagram of a CA is suitable for pattern classifier which divides pattern set into two classes. Maji et al. [1] classified patterns by using multiple attractor cellular automata as a pattern classifier with dependency vector. In this paper we propose a method of generation of a pattern classifier using feature vector which is the extension of dependency vector. In addition, we propose methods for finding nonreachable states in the 0-tree of the state transition diagram of TPMACA corresponding to the given feature vector for the analysis of the state transition behavior of the generated pattern classifier.