• Journal of the Korea Society of Computer and Information
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• v.27 no.2
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• pp.125-134
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• 2022

In this paper, we propose an extension method of the BR2K technique for enhancing the robustness of blockchain application services. The BR2K (Blockchain application, Replication & Recovery technique using Kubernetes) technique was recently developed to support the robustness of blockchain services through service replication and rapid restart. The proposed technique extends the existing BR2K technique to provide a state version, which is meta-information about the service state, and a method for safely managing it, and use the state version to determine the timing for service state recovery. Also, the technique provides systematic service state backup for service recovery and joining of new service nodes by utilizing the version information and the service registry which acts as a service recovery center in the BR2K technique. Based on this, it is possible to support new service nodes to join the replication service with consistency. As a result, new service nodes can be quickly added to the BR2K service in operation, enhancing the robustness of the BR2K service. In addition, the extended method is applied to the pilot blockchain application service and tested in a Kubernetes environment composed of virtual machines to confirm the validity of service replication consistency and rapid service recovery in the event of node failures.

• The Journal of Information Technology
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• v.12 no.4
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• pp.1-10
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• 2009

The robustness of communication service should be guaranteed to validate its security of the whole service not just high performance. One kind of practical test-beds is the chinese communication service based on SIM Card and GSM. In paper, we try to experiment the possibility of SIM cards clone in various mobile communications using 2G in china, and hence discovered the security vulnerabilities such as the incoming outgoing, SMS service and additional services on the mobile phones using clone SIM cards. The experiments show that chinese communication service should be prepared the Fraud Management System against the cloning SIM card. and furthermore, regulations related to the communication service should be tuned the realistic security environments.

• Journal of KIISE:Software and Applications
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• v.36 no.10
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• pp.800-815
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• 2009

Recently, Web services based service-oriented architecture is widely used to integrate effectively various applications distributed on the networks. In the service-oriented architecture BPEL as a standard modeling language for the business processes provides the way to integrate various services provided by applications. Over the past few years, some types of studies have been made on testing compatibility of services and on discriminating and tracing of the business processes in the services composition. Now a lot of studies about the services composition with BPEL are going on. However there were few efforts to solve the problems caused by the services composition. Especially, there is no effort to evaluate whether a composite service is reliable and whether it is robust against to exceptional situations. In this paper, we suggest a test framework and a testing method for robustness of the composite service written in WS-BPEL. For this, firstly we extract some information from the BPEL process and the participant services. Next, with the extracted information we construct the virtual testing environment that generates various faults and exceptional cases which may be raised within the real services. Finally the testing work for robustness of a composite service is performed on the test framework.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.77-86
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• 2020

In this paper, we propose a technique for blockchain service replication and recovery using kubernetes(BR2K) that robustly executes blockchain services based on replication and supports systematic recovery in case of the service failure. Blockchain services are being developed and applied in various fields such as administration, finance, and medical systems based on the features of blockchain, such as decentralization, high security, and data integrity. In such areas where service continuity is important, it is necessary to provide robustness for execution of blockchain services, and a recovery plan for service failure is also required. To this end, BR2K provides an execution replication technique that systematically supports the sustainable execution of blockchain application services. Also, it introduces a robust container registry based on the blockchain service registry, systematically supporting the recovery of service failures by using it. In addition, Truffle, a blockchain service development framework, is extended to utilize the Kubernetes container management tool, and BR2K provides a technique for rapidly deploying blockchain services using the extended framwork.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.229-236
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• 2023

As the importance and dependency of the positioning, navigation, and timing (PNT) information provided by the radio navigation satellite service (RNSS) increases, the vulnerability of RNSS to jamming can lead to significant risks. The signal design under the consideration of anti-jamming performance helps to provide service which is robust to jamming environment. Therefore, it is necessary to evaluate the jamming robustness performance during the design of new signals. In this paper, we introduce figures-of-merit (FoMs) that can be used for an anti-jamming performance analysis of designed signals of interest. We then calculate the FoMs, such as the quality factor (Q factor), tolerable jamming-to-signal ratio (tolerable J/S), and range to jammer (d) for legacy RNSS signals and analyze the results. Finally, based on the results of the analysis, we derive waveform design conditions to obtain good anti-jamming performance. As a result, this paper shows that the waveforms with wide bandwidth leading to good spectral efficiency provide strong anti-jamming performance.

• Journal of IKEEE
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• v.24 no.3
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• pp.743-753
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• 2020

In this paper, we propose a set of robustness indicators for immersive 360-degree video. With the full-fledged service of mobile carriers' 5G networks, it is possible to use large-capacity, immersive 360-degree videos at high speed anytime, anywhere. Since it can be illegally distributed in web-hard and torrents through DRM dismantling and various video modifications, however, evaluation indicators that can objectively evaluate the filtering performance for copyright protection are required. In this paper, a robustness indicators is proposed that applies the existing 2D Video robustness indicators and considers the projection method and reproduction method, which are the characteristics of Immersive 360-degree Video. The performance evaluation experiment has been carried out for a sample filtering system and it is verified that an excellent recognition rate of 95% or more has been achieved in about 3 second execution time.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.147.1-147
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• 2001

Future robots, especially service and personal robots, will need much more intelligence, robustness and user-friendliness. The ability to learn contributes to these characteristics and is, therefore, becoming more and more important. Three of the numerous varieties of learning are discussed together with results of real-world experiments with three autonomous robots: (1) the acquisition of map knowledge by a mobile robot, allowing it to navigate in a network of corridors, (2) the acquisition of motion control knowledge by a calibration-free manipulator, allowing it to gain task-related experience and improve its manipulation skills while it is working, and (3) the ability to learn how to perform service tasks ...

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.363-364
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• 2020

본 논문에서는 쿠버네티스와 블록체인 서비스 레지스트리를 이용한 블록체인 서비스 중복실행 기법을 제안한다. 이 기법은 컨테이너 관리 도구인 쿠버네티스를 이용하여 중복 실행 기법이 적용된 블록체인 서비스를 신속하게 실행할 수 있다. 또한 이 기법은 서비스 접근 위치, 복구를 위한 정보 등을 저장하는 블록체인 서비스 레지스트리를 이용하여 서비스 장애가 발생할 경우에 블록체인 서비스를 견고하게 실행할 수 있다.

• Smart Structures and Systems
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• v.20 no.2
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• pp.115-126
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• 2017

The modal identification of large civil structures such as bridges under the ambient vibrational conditions has been widely investigated during the past decade. Many operational modal analysis methods have been proposed and successfully used for identifying the dynamic characteristics of the constructed bridges in service. However, there is very limited research available on reliable criteria for the robustness of these identified modal parameters of the bridge structures. In this study, two time-domain operational modal analysis methods, the data-driven stochastic subspace identification (SSI-DATA) method and the covariance-driven stochastic subspace identification (SSI-COV) method, are employed to identify the modal parameters from field recorded ambient acceleration data. On the basis of the SSI-DATA method, the modal contribution indexes of all identified modes to the measured acceleration data are computed by using the Kalman filter, and their applicability to evaluate the robustness of identified modes is also investigated. Here, the benchmark problem, developed by Hong Kong Polytechnic University with field acceleration measurements under different excitation conditions of a cable-stayed bridge, is adopted to show the effectiveness of the proposed method. The results from the benchmark study show that the robustness of identified modes can be judged by using their modal contributions to the measured vibration data. A critical value of modal contribution index of 2% for a reliable identifiability of modal parameters is roughly suggested for the benchmark problem.