• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.12-12
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• 1992

This paper proposes an analysis method of Petri nets (PNs) using the relational algebra (RA). More specifically, we represent PNs in relations of the relational model. Based on such representation, we first develop an algorithms for analyzing properties of PNs, such as boundedness, conservation, coverability, reachability, and liveness. The advantage of this approach is as follows: First, the algorithms represented by RA can be easily converted to a query language such as SQL of the widely used, commercial relational database management systems (DBMSs). Second, we can alleviate the problem of state space explosion because relational DBMSs can handle large amounts of data efficiency. Finally, we can use the DBMS's query language to interpret the Petri nets and make simulation.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.37-47
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• 1992

This paper proposes an analysis method of petri nets(PNs) using the relational algebra(RA). More wpecifically, we represent PNs in relations of the relational model. Based on such representation, we first develop an algorithm for generating reachability trees of PNs. we then develop an algorithm for generating reachability trees of PNs. We then develop algorithms for analyzing properties of PNs, such as boundedness, conservation, coverability, reachability, and liveness. The advantage of this approach is as follows: First, the algorithms represented by RA can be easity converted to a query language such as SQL of the widely used, commerical relational database management systems(DBMSs). Second, we can alleviate the problem of state space explosion because relational DBMSs can handle large amounts of data efficiently. Finally, we can use the DBMS's query language to interpret the Petri nets and make simulation.

• International Journal of Computer Science & Network Security
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• v.21 no.12spc
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• pp.415-426
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• 2021

The implementation of iris biometrics on smartphone devices has recently become an emerging research topic. As the use of iris biometrics on smartphone devices becomes more widely adopted, it is to be expected that there will be similar efforts in the research community to beat the biometric by exploring new spoofing methods and this will drive a corresponding requirement for new liveness detection methods. In this paper we addresses the problem of presentation attacks (Spoofing) against the Iris Recognition System on mobile devices and propose novel Presentation Attack Detection (PAD) method which suitable for mobile environment.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.861-869
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• 2023

This article proposes a novel approach to measure the performance of Safety-Critical Systems (SCS). Such systems contain multiple processing nodes that communicate with each other is modeled by a Petri nets (PN). The paper uses the PN for the performance evaluation of SCS. A set of ordinary differential equations (ODEs) is derived from the Petri net model that represent the state of the system, and the solutions can be used to measure the system's performance. The proposed method can avoid the state space explosion problem and also introduces new metrics of performance, along with their measurement: deadlock, liveness, stability, boundedness, and steady state. The proposed technique is applied to Shutdown System (SDS) of Nuclear Power Plant (NPP). We obtained 99.887% accuracy of performance measurement, which proves the effectiveness of our approach.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.640-643
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• 2020

사진, 동영상 또는 3D 프린터로 변조된 얼굴을 이용한 안면인식 보안 우회 사례가 증가하였다. 따라서 본 논문에서는 얼굴인증 단계인 본인 여부와 Liveness Detection 및 OTP를 통한 다중인증 프레임워크를 구현함으로써 기존 단일인증 대비 더욱 안전한 인증 환경을 기대한다.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.354-357
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• 2004

According to the computerization of railway signaling systems, the interface link between the signaling systems has been replaced by the digital communication channel. At the same time, the importance of the communication link is more pronounced than in the past. In this paper, new network-based protocol for Korean railway signaling has designed between CTC and SCADA system, and the overview of designed protocol is briefly represented. Using the informal method for specifying the communication protocol, a little ambiguity may be contained in the protocol. To clear the ambiguity contained in the designed protocol, we use LTS model to design the protocol for this interface link between CTC and SCADA, the LTS is an intermediate model for encoding the operational behavior of processes. And then, we verify automatically and formally the safety and the liveness properties through the model checking method. Especially, the modal ${\mu}$-calculus, which is a highly expressive method of temporal logic that has been applied to the model checking method. It will be expected to increase the safety, reliability and efficiency of maintenance of the signaling systems by using the designed protocol for railway signaling in Korea.

• The KIPS Transactions:PartD
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• v.12D no.7 s.103
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• pp.931-936
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• 2005

There may be subtle errors in embedded software since its functionality is very complex. Thus formal verification for detecting them is very needed. Model checking is one of formal verification techniques, and SLAM is a well-known software model checking tool for verifying safety properties of embedded C program. In this paper, we develop a software model checker like SLAM for verifying embedded Java program Compared to SLAM, our tool allows to verify liveness properties as well as safety ones. As a result, we verify some desired properties in embedded Java program for controlling REGO robot.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.6
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• pp.380-387
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• 2004

In accordance with the computerization of railway signaling systems, the interface link between the signaling systems has been replaced by a digital communication channel. At the same time, the importance of the communication link has become increasingly significant. However, there are some questionable matters in the current state of railway signaling systems in KNR. First, different communication protocols have been applied to create an interface between railway signaling systems although the protocols have the same functions. Next, the communication protocols currently used in the railway fields have some illogical parts such as structure, byte formation, error correction scheme, and so on. To solve these matters, the standard communication protocol for railway signaling systems is designed. The newly designed protocol is overviews in this paper. And the simulation is performed to analysis the performance of data link control for designed protocol. According to this simulation, it is identified that the link throughput of new protocol is improved about 10% and the frame error rate is improved than existing protocol. And it is verified the safety and liveness properties of designed protocol by using a formal method for specifying the designed protocol. It is expected that there will be an increase in safety, reliability and efficiency in terms of the maintenance of the signaling systems by using the designed communication protocol for railway signaling.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.2
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• pp.173-184
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• 2000

The purposes of this study is for consideration of the flapper image through the culture and novels in Jazz Age(1919∼1929) of America. The back ground of flapper fashion was Jazz. Jazz was one of the cultural languages which expressed liveness, noise, salacity, harmony of primitivity, modernity, innocence and freedom. In processing American had gotten economic power, the Jazz Age had new mood which was combined materialism and realitism. Environmental changes of life styles and development of mass culture of modern big cities could aid the birth of modern girls, flappers. They became the main group of new consumer and mass culture in new consciousness and freedom with independence. Their characteristics are confirmed from Fitzgerald's novels, This Side of Paradise and The Great Gatsby. As the results of above, the consciousness of flapper were rebellious attitude, liberalism and actualism. The designs of flapper fashion were expressed by simplicity, functionality, nudity and rhythm. The flapper images are as follows: First, they expressed modern image as a rebellious attitude. Second, flapper had a sensual image of freedom through rhythmical and speedy expression. Third, premature image for pursuing youth could be found. Therefore the changes of culture and women's life styles are very important points for fashion studies and the connecting fashion and other fields like novels is needed also for it.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.4126-4142
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• 2015

Finger vein recognition is a biometric technology using finger veins to authenticate a person, and due to its high degree of uniqueness, liveness, and safety, it is widely used. The traditional Symmetric Local Graph Structure (SLGS) method only considers the relationship between the image pixels as a dominating set, and uses the relevant theories to tap image features. In order to better extract finger vein features, taking into account location information and direction information between the pixels of the image, this paper presents a novel finger vein feature extraction method, Multi-Orientation Weighted Symmetric Local Graph Structure (MOW-SLGS), which assigns weight to each edge according to the positional relationship between the edge and the target pixel. In addition, we use the Extreme Learning Machine (ELM) classifier to train and classify the vein feature extracted by the MOW-SLGS method. Experiments show that the proposed method has better performance than traditional methods.