• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.5
• /
• pp.2754-2767
• /
• 2019

Cloud computing is widely used in information spreading and processing, which has provided a easy and quick way for users to access data and retrieve service. Generally, in order to prevent the leakage of the information, the data in cloud is transferred in the encrypted form. As one of the traditional security technologies, access control is an important part for cloud security. However, the current access control schemes are not suitable for cloud, thus, it is a vital problem to design an access control scheme which should take account of complex factors to satisfy the various requirements for cipher text protection. We present a novel access control scheme based on proxy re-encryption(PRE) technology (PreBAC) for cipher text. It will suitable for the protection of data confidently and information privacy. At first, We will give the motivations and related works, and then specify system model for our scheme. Secondly, the algorithms are given and security of our scheme is proved. Finally, the comparisons between other schemes are made to show the advantages of PreBAC.

• BMB Reports
• /
• v.29 no.2
• /
• pp.175-179
• /
• 1996

Viral surface proteins are known to play an essential role in attachment of the virus particle to the host cell membrane. In case of the hepatitis B virus (HBV) several reports have described potential receptors on the target cell side, but no definite receptor protein has been isolated yet. As for the viral side, it has been suggested that the preS region of the envelope protein, especially the preS1 region, is involved in binding of HBV to the host cell. In this study, preS1 region was recombinantly expressed in the form of a maltose binding protein (MBP) fusion protein and used to identify and visualize the expression of putative HBV receptor(s) on the host cell. Using laser scanned confocal microscopy and by FACS analysis, MBP-preS1 proteins were shown to bind to the human hepatoma cell line HepG2 in a receptor-ligand specific manner. The binding kinetic of MBP-preS1 to its cellular receptor was shown to be temperature and time dependent. In cells permeabilized with Triton X-100 and treated with the fusion protein, a specific staining of the nuclear membrane could be observed. To determine the precise location of the receptor binding site within the preS1 region, several short overlapping peptides from this region were synthesized and used in a competition assay. In this way the receptor binding epitope in preS1 was revealed to be amino acid residues 27 to 51, which is in agreement with previous reports. These results confirm the significance of the preS1 region in virus attachment in general, and suggest an internalization pathway mediated by direct attachment of the viral particle to the target cell membrane.

• Journal of The Korean Association For Science Education
• /
• v.28 no.1
• /
• pp.15-23
• /
• 2008

This study analyzed the thinking types of pre-service chemical cell chemistry teachers according to grade and tried to find out how the education for pre-service teachers had influenced their thinking types. This study found that the pre-service education had failed to form scientific conceptions. Some pre-service teachers thought that college education couldn't help them understand the knowledge about chemical cell. In addition, they are lacking in scientific conception. Even some of them who thought college education was helpful had wrong conceptions. Most of the pre-service teachers' thoughts could not exceed the level of the high school chemistry textbooks. But, Juniors had more scientific conception than other grades through the group discussions about chemistry textbooks' contents in the course of "Theory of Science Teaching Materials". So, Pre-service education should include the pedagogical knowledge with content knowledge treated in secondary school science textbooks for educational effects.

• Geomechanics and Engineering
• /
• v.38 no.3
• /
• pp.319-334
• /
• 2024

The current theories on the interaction between surrounding rock and support in deep-buried tunnels do not consider the form of pre-reinforcement support or the flexibility of primary support, leading to a discrepancy between theoretical solutions and practical applications. To address this gap, a comprehensive mechanical model of the tunnel with pre-reinforced rock was established in this study. The equations for internal stress, displacement, and the radius of the plastic zone in the surrounding rock were derived. By understanding the interaction mechanism between flexible support and surrounding rock, the three-dimensional construction analysis solution of the tunnel could be corrected. The validity of the proposed model was verified through numerical simulations. The results indicate that the reduction of pre-deformation significantly influences the final support pressure. The pre-reinforcement support zone primarily inhibits pre-deformation, thereby reducing the support pressure. The support pressure mainly affects the accelerated and uniform movement stage of the surrounding rock. The generation of support pressure is linked to the deformation of the surrounding rock during the accelerated movement stage. Furthermore, the strength of the pre-reinforcement zone of the surrounding rock and the strength of the shotcrete have opposite effects on the support pressure. The parameters of the pre-reinforcement zones and support materials can be optimized to achieve a balance between surrounding rock deformation, support pressure, cost, and safety. Overall, this study provides valuable insights for predicting the deformation of surrounding rock and support pressure during the dynamic construction of deep-buried weak rock tunnels. These findings can guide engineers in improving the construction process, ensuring better safety and cost-effectiveness.

• Structural Engineering and Mechanics
• /
• v.38 no.2
• /
• pp.157-169
• /
• 2011

In this paper the time-dependent closed-form static solution of the suspended pre-stressed biconcave and biconvex cable trusses with unmovable, movable and elastic or viscoelastic yielding supports subjected to various types of vertical load is presented. Irvine's forms of the deflections and the cable equations are modified because the effects of the rheological behaviour needed to be incorporated in them. The concrete cable equations in the form of the explicit relations are derived and presented. From a solution of a vertical equilibrium equation for a loaded cable truss with rheological properties, the additional vertical deflection as a time-function is determined. The time-dependent closed-form model serves to determine the time-dependent response, i.e., horizontal components of cable forces and deflection of the cable truss due to applied loading at the investigated time considering effects of elastic deformations, creep strains, temperature changes and elastic supports. Results obtained by the present closed-form solution are compared with those obtained by FEM. The derived time-dependent closed-form computational model is used for a time-dependent simulation-based reliability assessment of cable trusses as is described in the second part of this paper.

• Journal of the Korean Chemical Society
• /
• v.66 no.3
• /
• pp.228-242
• /
• 2022

In this study, the educational effect was investigated by providing a teaching program so that pre-service chemistry teachers could apply model ignorance education to teacher training practice. The teaching program was constructed in consideration of the sensemaking concept proposed in the study of Odden & Russ and the process of teacher sensemaking proposed by Asli et al. The subjects of this study were 23 pre-service teachers in the 4th year of chemistry education department at a teacher training university in the central region of Korea. In order to form a sensemaking for the model's ignorance education, the teaching program consisted of four stages; the initial idea generation stage, cognition of model's ignorance stage in a inconsistent situation, the lesson strategy construction stage for model ignorance education, and lesson plan & practice stage during teacher training practice. In the first stage of this program, pre-service teachers' initial ideas about the Arrhenius model and Bronsted-Lowry model of acid-base reaction, and the electron transfer model of the oxidation-reduction reaction were investigated. In the second stage, inconsistant situation that cannot be explained by the knowledge of model was presented to recognize the ignorance of the model. The third stage was to develop the teaching ability of model's ignorance through textbook analysis and lesson strategy composition activities. As a final stage, during the teacher training practice, the pre-service teachers were asked to plan and practice the implementation of the model's ignorance education. Through the teaching program to form a sensemaking for ignorance education of the models, pre-service teachers had come to recognize the ignorance of the model, acquired ability to organize and execute lesson strategies reflecting model ignorance, and acquired recognition of the educational value and necessity of teaching the ignorance of models.

• Journal of Digital Convergence
• /
• v.16 no.5
• /
• pp.435-443
• /
• 2018

This study explores the effects of different Focus-on-Form Instruction (FFI) on improving learners' grammatical knowledge development and observes how the learners apply the knowledge to their output. A total of 112 college students were placed into three groups: 35 input-enhanced group students, who received visually enhanced input reading materials, 41 output-enhanced group students, performing dictogloss tasks, and 46 control group students given traditional grammar instruction. All the participant students took pre/post grammatical tests and completed pre/post writing tasks, which aimed to look into how the target grammatical structures were used in writing. The research findings indicated that both input-enhanced and output-enhanced FFI were effective on learners' language form learning and made contribution to their writing. Based on the findings, this study suggests that the elaborate design of combination of both FFI can maximize learners' language form learning.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.4
• /
• pp.30-37
• /
• 2015

Needs for high ash loading in printing paper increase as green house gas (GHG) emission regulation becomes more stricter and pressure of lowering paper production cost increases. To meet the needs, a new type of filler was developed. The mixture of ground calcium carbonate (GCC) and calcium oxide was pre-floccuated with polyelectrolyte and further treated with carbon dioxide to form new calcium carbonate between GCCs. The final products were called as hybrid calcium carbonate (HCC), and its properties were compared to the GCC and the pre-flocculated GCC. Results showed increase in tensile, smoothness, opacity, and bulk for HCC.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.4
• /
• pp.338-346
• /
• 2013

Equations of motion of a rotating blade considering pre-twist angle, cross section taper and a concentrated mass are derived using the hybrid deformation variable modeling method. For the modeling of a concentrated mass which is located at an arbitrary position of the blade, a Dirac delta function is employed for the mass density function. The final equations for the vibration analysis are transformed into a dimensionless form using several dimensionless parameters. The effects of the dimensionless parameters on the vibration characteristics of the rotating blade are investigated through numerical analysis.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.32 no.1
• /
• pp.70-77
• /
• 2008

A pre-processing program based on the OOP(object-oriented programming) concept has been developed. The program consists of the input of a 2D or 3D flow problem to a CFD program by means of an user-friendly interface and the subsequent transformation of this input into a form suitable for the solver(PowerCFD) using unstructured cell-centered method. User-friendly GUI(graphic user interface) has been built on the base of MFC(Microsoft Foundation Class). The program is organized as modules by classes based on VTK(Visualization ToolKit)-library, and these classes are made to function through inheritance and cooperation which is an important and valuable concept of object-oriented programming. The major functions of this program are introduced and demonstrated, which include mesh generation, boundary settings, solver settings, generation of grid connectivity and geometric data etc.