• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.93-103
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• 2005

As the usage of XML documents increases the requirement of security for XML documents is growing. Especially it is very important to solve the problem of access control to XML object which shares in the environment where various users connect to each others. In this paper, we propose the access control model and mechanism which is combined with role hierarchy in the RBAC and hierarchical key derivation/assign method for the access to XML object. So we implement the access control mechanism by including hierarchical key derivation method. The technique, we proposed, gives not only the benefit in management which RBAC provides in access control to XML objects, but also it ran help derive a lower layer key from the higher layer user's. This feature decrease the number of keys managed in each role hierarchy in comparison with previous methods.

• Research in Mathematical Education
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• v.23 no.4
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• pp.235-254
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• 2020

Through this study, we aimed to capture the nature of a mathematics method course, called "the Curriculum Development and Teaching Methods in Mathematics Education" which is a pedagogy course for teaching for secondary school mathematics taught at a university located in a south eastern part of South Korea. The research participants include three junior students who took the methods course and a local high school math teacher with two professors. The research has three parts. First, we designed a method course to prepare the junior or senior students for a teaching practicum. The individual students gave a mini lecture about a secondary mathematical topic as a course requirement. Second, the three students watched a classroom video-clip of the high school teacher and analyzed his instruction before the actual classroom visits. Furthermore, by "Let's Learn" program for students, the course was associated with a local community through the students and so that they could visit the teacher's classroom three times to observe his math classroom teaching. The students discussed the difference between their own mini lectures and the actual math classroom teaching to develop an understanding of what it entails to teach an actual math class. Third, the first author supervised the students' activities in the program including their report for it to bring out their findings to the class of the method course. We found out this method course provided the students with the experience of various aspects of actual math lesson as well as learning theories about the pedagogy for teaching for secondary school mathematics. We conclude that this course gives a model for the method course in mathematics education for secondary school mathematics.

• Journal of The Korean Association of Information Education
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• v.24 no.6
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• pp.563-572
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• 2020

In this study, through a total of 73 lectures and practice for 14 days, preliminary coding instructors developed teaching materials for elementary and junior high school students and verified the effectiveness of the coding instructor training course. The coding instructor training course was hosted by the "◯◯ Creative Economy Innovation Center" for 25 preliminary coding instructors, and was conducted at the "◯◯ University", and 15 elementary and junior high school students who participated in the class were openly recruited. The teaching materials were developed according to the procedure of the ADDIE model based on the results of the pre-requirement analysis conducted with 20 incumbent elementary school teachers majoring in computer education. As a result of running a training course for coding instructors focusing on classroom practice, it was found that the creativity of pre-coding instructors improved.

• Structural Monitoring and Maintenance
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• v.8 no.4
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• pp.329-344
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• 2021

The use of structural control devices to minimize structural response to seismic/dynamic excitations has attracted increased attention in recent years. The use of magnetorheological (MR) dampers as a control device have captured the attention of researchers in this field due to its flexibility, adaptability, easy control, and low power requirement compared to other control devices. However, little attention has been paid to the effect of configuration and number of dampers installed in a structure on responses reduction. This study assesses the control of a five-story structure using one and two MR dampers at different stories to determine the optimal damper positions and configurations based on performance indices. This paper also addresses the fail-safe current value to be applied to the MR damper at each floor in the event of feedback or control failure. The model is mathematically simulated in SIMULINK/MATLAB environment. Linear control strategies for current at 0 A, 0.5 A, 1 A, 1.5 A, 2 A, and 2.5 A are implemented for MR dampers, and the response of the structure to these control strategies for different configurations of dampers is compared with the uncontrolled structure. Based on the performance indices, it was concluded that the dampers should be positioned starting from the ground floor, then the 2^nd floor followed by 1^st and rest of the floors sequentially. The failsafe value of current for MR dampers located in lower floors (G+1) should be kept at a higher value compared to dampers at top floors for effective passive control of multi-story structures.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.37-50
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• 2022

Modern supply chains include multiple activities from collecting raw materials to transferring final products. These activities involve many parties who share a huge amount of valuable data, which makes managing supply chain systems a challenging task. Current supply chain management (SCM) systems adopt digital technologies such as the Internet of Things (IoT) and blockchain for optimization purposes. Although these technologies can significantly enhance SCM systems, they have their own limitations that directly affect SCM systems. Security, performance, and scalability are essential components of SCM systems. Yet, confidentiality and scalability are one of blockchain's main limitations. Moreover, IoT devices are lightweight and have limited power and storage. These limitations should be considered when developing blockchain-based IoT-SCM systems. In this paper, the requirements of efficient supply chain systems are analyzed and the role of both IoT and blockchain technologies in providing each requirement are discussed. The limitations of blockchain and the challenges of IoT integration are investigated. The limitations of current literature in the same field are identified, and a secure and scalable blockchain-based IoT-SCM system is proposed. The proposed solution employs a Hyperledger fabric blockchain platform and tackles confidentiality by implementing private data collection to achieve confidentiality without decreasing performance. Moreover, the proposed framework integrates IoT data to stream live data without consuming its limited resources and implements a dualstorge model to support supply chain scalability. The proposed framework is evaluated in terms of security, throughput, and latency. The results demonstrate that the proposed framework maintains confidentiality, integrity, and availability of on-chain and off-chain supply chain data. It achieved better performance through 31.2% and 18% increases in read operation throughput and write operation throughput, respectively. Furthermore, it decreased the write operation latency by 83.3%.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.249-259
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• 2010

Synthetic environment data used in defense M&S fields, which came from various organization and source, are consumed and managed by their own native database system in distributed environment. But to manage these diverse data while interoperation in HLA/RTI environment, neutral synthetic environment data model is necessary to transmit the data between native database. By the support of DMSO, SEDRIS was developed to achieve this requirement and this specification guarantees loss-less data representation, interchange and interoperability. In this research, to use SEDRIS as a standard simulation database, base research, visualization for validation, data interchange experiment through test-bed was done. This paper shows each research case, result and future research direction, to propose standardized SEDRIS usage process.

• Journal of the Korea Society for Simulation
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• v.18 no.1
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• pp.27-34
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• 2009

Currently network users, especially the number of internet users, increase rapidly. Also, high quality of service is required and this requirement results a sudden network traffic increment. As a result, an efficient management system for huge network traffic becomes an important issue. Ontology/data engineering based context awareness using the System Entity Structure (SES) concepts enables network administrators to access traffic data easily and efficiently. The network traffic analysis system, which is studied in this paper, is designed and implemented based on a model and simulation using data engineering methodology to be avaiable in evaluating large network traffic data. Extensible Markup Language (XML) is used for metadata language in this system. The information which is extracted from the network traffic analysis system could be modeled and simulated in Discrete Event Simulation (DEVS) methodology for further works such as post simulation evaluation, web services, and etc.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.1
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• pp.271-280
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• 2016

In recent years, most domestic colleges of engineering are continuously trying to enhance the quality of education in engineering so as to meet the international requirement of education standards of this era. In consequence, the colleges are willing to acquire the accreditation of education by the ABEEK (Accreditation Board for Engineering Education of Korea) so that they can find the right way for the education of engineering and establish concrete educational programs in engineering. In this contribution, we exemplify a case of the College of Engineering in Mokwon University to survey and analyze the current state of education in engineering. We adopt the AS-IS and TO-BE analysis model to assess the system and try to figure out the right way for custom-designed education. The analysis helps understanding of the current situation of local private universities and consequently be used as important data for acquiring the engineering accreditation for global standard.

• Steel and Composite Structures
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• v.46 no.6
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• pp.773-791
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• 2023

Connections with damage concentrated to pre-selected components can enhance seismic resilience for moment resisting frames. These pre-selected components always yield early to dissipate energy, and their energy dissipation mechanisms vary from one to another, depending on their position in the connection, geometry configuration details, and mechanical characteristics. This paper presents behaviour insights on two types of beam-to-beam connections that the angles were designed as energy dissipation components, through the results of experimental study and finite element analysis. Firstly, an experimental programme was reviewed, and key responses concerning the working mechanism of the connections were presented, including strain distribution at the critical section, section force responses of essential components, and initial stiffness of test specimens. Subsequently, finite element models of three specimens were established to further interpret their behaviour and response that were not observable in the tests. The moment and shear force transfer paths of the composite connections were clarified through the test results and finite element analysis. It was observed that the bending moment is mainly resisted by axial forces from the components, and the dominant axial force is from the bottom angles; the shear force at the critical section is primarily taken by the slab and the components near the top flange. Lastly, based on the insights on the load transfer path of the composite connections, preliminary design recommendations are proposed. In particular, a resistance requirement, quantified by a moment capacity ratio, was placed on the connections. Design models and equations were also developed for predicting the yield moment resistance and the shear resistance of the connections. A flexible beam model was proposed to quantify the shear resistance of essential components.

• Clinical Endoscopy
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• v.56 no.1
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• pp.65-74
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• 2023

Background/Aims: Gastric varices (GV) are present in 25% of cirrhotic patients with high rates of rebleeding and mortality. Data on endoscopic ultrasound (EUS)-guided treatment in severe liver disease (model for end stage liver disease sodium [MELD-Na] >18 and Child-Turcotte-Pugh [CTP] C with GV) are scarce. Thus, we performed a retrospective comparison of endoscopic glue injection with EUS-guided therapy in cirrhotic patients with large GV. Methods: A retrospective study was performed in the tertiary hospitals of India. A total of 80 patients were recruited. The inclusion criteria were gastroesophageal varices type 2, isolated gastric varices type 1, bleeding within 6 weeks, size of GV >10 mm, and a MELD-Na >18. Treatment outcomes and complications of endoscopic glue injection and EUS-guided GV therapy were compared. Results: In this study, the patients' age, sex, liver disease severity (CTP, MELD-Na) and clinical parameters were comparable. The median number of procedures, injected glue volume, complications, and GV obturation were better in the EUS group, respectively. On subgroup analysis of the EUS method (e.g., direct gastric fundus vs. paragastric collateral [PGC] coil placement), PGC coil placement showed decreased coil requirement, less injected glue volume, decreased luminal coil extrusion, and increased successful GV obturation. Conclusions: EUS-guided treatment is more efficient and safer, and requires a smaller number of treatment sessions, as compared to endoscopic treatment in severe liver disease patients with large GV. Furthermore, PGC coil placement increases the complete obliteration of GV.