• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.22 no.6
• /
• pp.519-525
• /
• 2009

In this study a cohesive zone model was used to simulate the delamination phenomena which occurs by a successive crack initiation and propagation in composite laminates. The cohesive zone model was incorporated to the classical finite element method via cohesive element formulation and then implemented into the user-subroutine UEL of a commercial finite element program Abaqus. To validate the formulation and implementation of the cohesive element the finite element results were compared with the experimental data of double cantilever beam and end notched flexure tests. The numerical results well agree with the experimental load-displacement curves. Also the effect of the elastic stiffness and the size of the cohesive element on the global load-displacement curves were studied numerically. To minimize the mesh-dependency of the crack propagation path and eliminate the zig-zag patterns in the load-displacement curve, cohesive elements should be refined at the crack-tip.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.32 no.6
• /
• pp.1113-1120
• /
• 2022

Recently, the investigation has been difficult due to the emergence of messengers that encrypt and store data for the purpose of protecting personal information and provide services such as end-to-end encryption with a focus on security. Accordingly, the number of crime cases using security messengers is increasing, but research on data decoding for security messengers is needed. Element security messengers provide end-to-end encryption functions so that only conversation participants can check conversation history, but research on decoding them is insufficient. Therefore, in this paper, we analyze the instant messenger Element, which provides end-to-end encryption, and propose a plaintext verification of the history of encrypted secure chat rooms using decryption keys stored in the Windows Credential Manager service without user passwords. In addition, we summarize the results of analyzing significant general and secure chat-related artifacts from a digital forensics investigation perspective.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1A
• /
• pp.237-246
• /
• 2006

In order to evaluate the seismic performance of damaged reinforced concrete members, particularly bridge piers, an inelastic time-dependent element is proposed. The proposed element enables increased characteristics due to structural intervention(i.e., repair or retrofitting) to be accurately reflected to the degraded strength and stiffness of the members. The inelastic time-dependent element having both birth and death time can freely be activated within the user-defined time intervals during static and dynamic time-history analysis. Comparative studies are carried out for reinforced concrete bridge piers that are repaired and retrofitted. Analytical predictions using the developed element show reasonable correlation with experimental results. Also conducted is a nonlinear time-history analysis of a reinforced concrete bridge under multiple earthquakes. The comparative analytical results prove the validation of current development. In all, it is concluded that the present element is capable of providing salient features for the healthy evaluation of seismic performance and hence seismic stability assessment of RC bridge piers being repaired and retrofitted.

• The Journal of Society for e-Business Studies
• /
• v.24 no.1
• /
• pp.29-48
• /
• 2019

Recently, product design innovation to improve user experience has been perceived as a core element of enterprise competitiveness due to the fierce market competition and decrease of the technological gap between companies, but there is insufficient services to support the product experience evaluation of small and medium-sized companies (SMCs). The aim of this study is to develop a web-based product user experience evaluation and certification system supporting product design practices for SMCs. For system interface design, we conducted systematic functional requirement elicitation methods such as user survey, workflow analysis, user task definition, and function definition. Then main functions, information structure, navigation method, and detailed graphic user interfaces were developed with consideration of user interactions and requirements. In particular, it provides the databases for evaluation efficiency to support the evaluation process above a certain level of performance and efficiency, and knowledge databases to utilize in the evaluation and product design improvement. With help of the developed service platform, It is expected that the service platform would enhance SMCs' product development capability with regard to the user experience evaluation by connecting the consulting firms with SMCs.

• Design Convergence Study
• /
• v.14 no.4
• /
• pp.181-192
• /
• 2015

The layout includes various functions not only arrangement, connection, division of information but also affordance and information recognition as the important element that determine the whole structure of information. Recently, the layout of web interface design was gradually changing from the concept of the original Z-layout to F-layout, whereas, it is being changed again into the split layout as the transform of Z-layout. However, there can be lack of grounds as to the reason of the change of layout. Therefore, it needs to study on how the functional difference between the F-layout and Z-layout affects user experience. In this study, we conduct the study on the effect of each layout type on the user experience focusing on the product description of web-page by user test. The user test have shown that the user has better feeling on the split layout based on the Z-layout than F-layout. The Z-layout also has more advantages on the formation of the favorable attitude of user in efficiency, accessibility and concentration. This result is consistent with the trend of web-design to change into the split layout based on the Z-layout and we provided the objective reasons for the effective web-design layout by user test.

• The Journal of the Korea Contents Association
• /
• v.14 no.10
• /
• pp.64-72
• /
• 2014

As the importance of interface became emphasized recently, function of icon as an element that helps operation and formative function as an aesthetic element are becoming emphasized. Specially, various research methodologies for measuring the understanding degree of users are being attempted in functional aspect, however, they are facing limitations as user evaluation method of quantitative investigation for statistical analysis became overly dependent on the consent from majority. To overcome such limitation, a methodology of measuring sensibility as aesthetic impression or individuality based on the system of emotion or system of understanding of users and designing icon based on the measurement is being attempted continuously. Therefore, this study suggested an evaluation method using reminding words and conducted an empirical study to apply results on the icon design by applying the evaluation method on icon design of printing products to measure the user sensibility and understanding level. Through this process, this study intended to research summaries on the design evaluation method which based on the evaluation of user sensibility and understanding level and to debate effective design methodologies through the process of applying these summaries on the project. The intention was to progress discussion from practical application perspectives apart from the textbook type discussion by applying a research methodology through concrete cases. This study objectified sensibility and understanding level of users in the icon design aspect, suggested a methodology that can be applied on the design, and it is expected to be used when progressing the icon and GUI design.

• Asia pacific journal of information systems
• /
• v.18 no.4
• /
• pp.1-26
• /
• 2008

Rapid progress of information technology and widespread use of the personal computers have brought various conveniences in our life. But this also provoked a series of problems such as hacking, malicious programs, illegal exposure of personal information etc. Information security threats are becoming more and more serious due to enhanced connectivity of information systems. Nevertheless, users are not much aware of the severity of the problems. Using appropriate password is supposed to bring out security effects such as preventing misuses and banning illegal users. The purpose of this research is to empirically analyze a research model which includes a series of factors influencing the effectiveness of passwords. The research model incorporates the concept of risk based on information systems risk analysis framework as the core element affecting the selection of passwords by users. The perceived risk is a main factor that influences user's attitude on password security, security awareness, and intention of security behavior. To validate the research model this study relied on questionnaire survey targeted on evening class MBA students. The data was analyzed by AMOS 7.0 which is one of popular tools based on covariance-based structural equation modeling. According to the results of this study, while threat is not related to the risk, information assets and vulnerability are related to the user's awareness of risk. The relationships between the risk, users security awareness, password selection and security effectiveness are all significant. Password exposure may lead to intrusion by hackers, data exposure and destruction. The insignificant relationship between security threat and perceived risk can be explained by user's indetermination of risk exposed due to weak passwords. In other words, information systems users do not consider password exposure as a severe security threat as well as indirect loss caused by inappropriate password. Another plausible explanation is that severity of threat perceived by users may be influenced by individual difference of risk propensity. This study confirms that security vulnerability is positively related to security risk which in turn increases risk of information loss. As the security risk increases so does user's security awareness. Security policies also have positive impact on security awareness. Higher security awareness leads to selection of safer passwords. If users are aware of responsibility of security problems and how to respond to password exposure and to solve security problems of computers, users choose better passwords. All these antecedents influence the effectiveness of passwords. Several implications can be derived from this study. First, this study empirically investigated the effect of user's security awareness on security effectiveness from a point of view based on good password selection practice. Second, information security risk analysis framework is used as a core element of the research model in this study. Risk analysis framework has been used very widely in practice, but very few studies incorporated the framework in the research model and empirically investigated. Third, the research model proposed in this study also focuses on impact of security awareness of information systems users on effectiveness of password from cognitive aspect of information systems users.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.1
• /
• pp.35-42
• /
• 2021

This paper presents an on-line finite element model updating method for in-service structures using measured data. Conventional updating methods, which are based on numerical optimization, are not efficient for on-line updating because they generally require repeated eigenvalue analyses until convergence criteria are met. The proposed method enables fully automated on-line finite element model updating, almost simultaneously with vibration measurement, without any user intervention or off-line procedures. The automated covariance-driven stochastic subspace identification (Cov-SSI) method is utilized to identify modal frequencies and vectors, and the identified modal data is fed to the neural network of the inverse eigenvalue function to produce the updated finite element model parameters. Numerical examples for a wind excited 20-story building structure shows that the proposed method can update the series of finite element model parameters automatically. It is also shown that sudden changes in the structural parameters can be detected and traced successfully.

• Journal of the Korean Society for information Management
• /
• v.3 no.1
• /
• pp.70-102
• /
• 1986

This study is an attempt to develop a knowledge base with Inference mechanism for document retrieval, which is the core element of expert system. The purpose of this study is to design the knowledge base in order to intellectually process user queries eventually improving the effectiveness of information retrieval, under the assumption that the user who wants to search a certain subject generally lack the prior knowledge about that subject. In this paper, some characteristics of Korean complex nouns are structurally analyzed and are represented in the knowledge base.

• Transactions of Materials Processing
• /
• v.12 no.2
• /
• pp.110-115
• /
• 2003

This paper is concerned with the compression test and forming process of flange by using virtual reality and analysis(simulation) program. This virtual manufacturing can be carried out one personal computer without any expensive devices for experiment. The virtual manufacturing composed of three modules such as the imput, calculation and the output modules on internet. Internet user can give the material's property and process parameters to the sever computer at the input module. On the calculation module, a simulator computes the virtual manufacturing process by analysis program and stores the data as a file. The output module is the program in which internet user can confirm virtual manufacturing results by showing tables, graphs, and 3D animation. This programs is designed by an internet language such as HTML, CGI, VRML and JAVA ,while analysis programs use the finite increasing, the virtual manufacturing technique will substitute many real experiments in the future.