• Earthquakes and Structures
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• 제9권4호
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• pp.911-936
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• 2015

This work evaluates the performance of a number of seismic assessment procedures when applied to a case study reinforced concrete (RC) wall building. The performance of each procedure is evaluated through its ability to accurately predict deformation demands, specifically, roof displacement, inter-storey drift ratio and wall curvatures are considered as the key engineering demand parameters. The different procedures include Direct Displacement-Based Assessment, nonlinear static analysis and nonlinear dynamic analysis. For the latter two approaches both lumped and distributed plasticity modelling are examined. To thoroughly test the different approaches the case study building is considered in different configurations to include the effects of unequal length walls and plan asymmetry. Recommendations are made as to which methods are suited to different scenarios, in particular focusing on the balance that needs to be made between accurate prediction of engineering demand parameters and the time and expertise required to undertake the different procedures. All methods are shown to have certain merits, but at the same time a number of the procedures are shown to have areas requiring further development. This work also highlights a number of key aspects related to the seismic response of RC wall buildings that may significantly impact the results of an assessment. These include the influence of higher-mode effects and variations in spectral shape with ductility demands.

• Journal of Computing Science and Engineering
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• 제10권3호
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• pp.75-84
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• 2016

Medical cyber-physical systems (MCPS) integrate sensors, actuators, and software to improve patient safety and quality of healthcare. These systems introduce major challenges to safety analysis because the patient's physiology is complex, nonlinear, unobservable, and uncertain. To cope with the challenge that unidentified physiological parameters may exhibit short-term variances in certain clinical scenarios, we propose a novel run-time predictive safety monitoring technique that leverages a maximal model coupled with online training of a computational virtual subject (CVS) set. The proposed monitor predicts safety-critical events at run-time using only clinically available measurements. We apply the technique to a surgical glucose control case study. Evaluation on retrospective real clinical data shows that the algorithm achieves 96% sensitivity with a low average false alarm rate of 0.5 false alarm per surgery.

• Journal of Multimedia Information System
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• 제7권3호
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• pp.215-220
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• 2020

Many state agencies and companies collect personal data for the purpose of providing public services and marketing activities and use it for the benefit and results of the organization. In order to prevent the spread of COVID-19 recently, personal data is being collected to understand the movements of individuals. However, due to the lack of technical and administrative measures and internal controls on collected personal information, errors and leakage of personal data have become a major social issue, and the government is aware of the importance of personal data and is promoting the protection of personal information. However, theory-based training and document-based intrusion prevention training are not effective in improving the capabilities of the privacy officer. This study analyzes the processing steps and types of accidents of personal data managed by the organization and describes measures against personal data leakage and misuse in advance. In particular, using Capture the Flag (CTF) scenarios, an evaluation platform design is proposed to respond to personal data breaches. This design was proposed as a troubleshooting method to apply ISMS-P and ISO29151 indicators to reflect the factors and solutions to personal data operational defects and to make objective measurements.

• 한국항행학회논문지
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• 제13권5호
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• pp.630-638
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• 2009

본 논문에서는 SCADE를 사용하여 항공기 안전필수 시스템인 공중충돌회피시스템(TCAS-II)을 위한 통합 시뮬레이터를 설계한다. 이 TCAS-II시뮬레이터는 기존의 충돌회피 알고리즘의 문제점을 분석하고 실제 공중충돌 상황을 더욱 현실성 있게 시스템 평가에 반영할 수 있도록 편리한 통합시뮬레이션 환경을 반영하여 구현한다. 또한 안전 필수요건인 소프트웨어 국제표준 신뢰성 요건을 만족하면서 실제로 실험할 수 없는 상황에 대한 TCAS-II의 성능분석 및 새로운 충돌회피 로직 연구를 위한 시나리오 편집기를 제시하고 이를 사용하여 전형적인 공중충돌 시나리오에 대한 시뮬레이션을 통해 그 성능을 검증한다.

• 한국항해항만학회지
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• 제34권4호
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• pp.287-292
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• 2010

The purpose of this study was to create a cyber-training & education program in response to the needs of skippers and crews operating tug-barges within Korean coastal waters and the rapid changers in this industry. Skippers and crews are inclined to operate tug-barges on the basis of experience rather than information. It is not easy to provide useful information whenever they want or to drill them in safety management skills, because of their passive attitude toward education and the few opportunities that exist. In order to increase educational opportunities, efficiency and motivation, the authors have developed this program which consists of a 'tug bridge resource management module, risk perception training module, accident case module, operating module and navigation module', and are hoping that this program will enhance and strengthen all tug-barge operations. We are also putting all our energies into designing up to date animation programs and developing new scenarios concerning the method of evaluation and certification distribution.

• 대한안전경영과학회지
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• 제17권1호
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• pp.33-43
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• 2015

Modern systems development becomes more and more complicated due to the need on the ever-increasing capability of the systems. In addition to the complexity issue, safety concern is also increasing since the malfunctions of the systems under development may result in the accidents in both the test and evaluation phase and the operation phase. Light rail transit(LRT) with passenger capacity between bus and subway is driven by an unmanned control, so safety issues of LRT in emergency shall be considered more carefully than other rolling stock. Modern railway system is a complex system and many actions in emergency are required. In this view, interoperability approach is effective to identify the related elements in emergency. In this paper, we propose the method to generate the fire response scenario of unmann ed LRT based on the outputs of systems engineering architecture design methodology. The proposed method is could be contributed to establish more reliable and applicable fire response scenario.

• 융합보안논문지
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• 제8권1호
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• pp.91-100
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• 2008

The previous works in sensor networks security have focused on the aspect of confidentiality, authentication and integrity based on cryptographic primitives. There has been no prior work to assess the survivability in systematic way. Accordingly, this paper presents a survivability model of wireless sensor networks using software rejuvenation for dual adaptive cluster head. The survivability model has state transition to reflect status of real wireless sensor networks. In this paper, we only focus on a survivability model which is capable of describing cluster head compromise in the networks and able to switch over the redundant cluster head in order to increase the survivability of that cluster. Second, this paper presents how to enhance the survivability of sensor networks using software rejuvenation methodology for dual cluster head in wireless sensor network. We model and analyze each cluster as a stochastic process based on Semi Markov Process (SMP) and Discrete Time Markov Chain (DTMC). The proof of example scenarios and numerical analysis shows the feasibility of our approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2377-2397
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• 2020

Human activity recognition is widely used in smart homes, health care and indoor monitor. Traditional approaches all need hardware installation or wearable sensors, which incurs additional costs and imposes many restrictions on usage. Therefore, this paper presents a novel device-free activities recognition system based on the advanced wireless technologies. The fine-grained information channel state information (CSI) in the wireless channel is employed as the indicator of human activities. To improve accuracy, both amplitude and phase information of CSI are extracted and shaped into feature vectors for activities recognition. In addition, we discuss the classification accuracy of different features and select the most stable features for feature matrix. Our experimental evaluation in two laboratories of different size demonstrates that the proposed scheme can achieve an average accuracy over 95% and 90% in different scenarios.

• Earthquakes and Structures
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• 제18권3호
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• pp.391-405
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• 2020

The use of passive energy dissipation devices has been widely used in the construction industry to minimize the probability of damage occurred under intense ground motion. In this study, collapse margin ratio (CMR) and fragility curves are the main parameters in the assessment to characterize the collapse safety of the structures. The assessment is done on three types of RC frame structures, incorporating three types of dampers, viscoelastic, friction, and BRB dampers. The Incremental dynamic analyses (IDA) were performed by simulating an array of 20 strong ground motion (SGM) records considering both far-field and near-field seismic scenarios that were followed by fragility curves. With respect to far-field ground motion records, the CMR values of the selected frames indicate to be higher and reachable to safety margin more than those under near-field ground motion records that introduce a high devastating impact on the structures compared to far-field excitations. This implies that the near field impact affects the ground movements at the site by attenuation the direction and causing high-frequency filtration. Besides that, the results show that the viscoelastic damper gives better performance for the structures in terms of reducing the damages compared to the other energy dissipation devices during earthquakes.

• 대한인간공학회지
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• 제23권4호
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• pp.9-21
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• 2004

As menu structure of household appliance is complicated, user's cognitive workload frequently occurs errors. In existing studies, errors didn't present that interpretation for cognitive factors and alternatives, but are only considered as statistical frequency. Therefore, error classification and analysis in tasks is inevitable in usability evaluation. This study classified human error throughout information process model and navigation behavior. Human error is defined as incorrect decision and behavior reducing performance. And navigation is defined as unrelated behavior with target item searching. We searched and analyzed human errors and its causes as a case study, using mobile phone which could control appliances in near future. In this study, semantic problems in menu structure were elicited by SAT. Scenarios were constructed by those. Error analysis tests were performed twice to search and analyze errors. In 1st prototype test, we searched errors occurred in process of each scenario. Menu structure was revised to be based on results of error analysis. Henceforth, 2nd Prototype test was performed to compare with 1st. Error analysis method could detect not only mistakes, problems occurred by semantic structure, but also slips by physical structure. These results can be applied to analyze cognitive causes of human errors and to solve their problems in menu structure of electronic products.