• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.261-269
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• 2014

There are many researches on fast exponentiation algorithm which is used to implement a public key cryptosystem such as RSA. On the other hand, the malicious attacker has tried various side-channel attacks to extract the secret key. In these attacks, an attacker uses the power consumption or electromagnetic radiation of cryptographic devices which is measured during computation of exponentiation algorithm. In this paper, we propose a novel simple power analysis attack on m-ary exponentiation implementation. The core idea of our attack on m-ary exponentiation with pre-computation process is that an attacker controls the input message to identify the power consumption patterns which are related with secret key. Furthermore, we implement the m-ary exponentiation on evaluation board and apply our simple power analysis attack to it. As a result, we verify that the secret key can be revealed in experimental environment.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.48-60
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• 1996

This paper present a new technique for doing realistic computer animation. The method is based on forward dynamic simulation and nonlinear problem solving (parameter optimization) technique. Objects are modelled physically and simulated faithfully while satisfying kinematic and geometric constraints. This forward dynamic simulation gives us very realistic motions especially for non-voluntary motions. Then we extend simulation technique to do animation using parameter optimization. The basic idea is to add motion control over the entire animation. The motion control is finding optimal solutions while satisfying user's animation goals. We provide two different animation technique; one is for rigid body without joint actuators and the other is for rigid body with linear joint actuators. To achieve motion control, we convert single simulation to single nonliner function evaluation while either setting initial conditions as variables for the function or allocating control variables in terms of time. This method is presented with two animation examples: dice-magic and human stand-up.

• Geomechanics and Engineering
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• v.16 no.4
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• pp.399-413
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• 2018

This paper addresses the issue of field measurement of excavation damage zone (EDZ) and its numerical simulation method considering both excavation unloading and blasting load effects. Firstly, a 2000 m-deep rock cavern in China is focused. A detailed analysis is conducted on the field measurement data regarding the mechanical response of rock masses subjected to excavation and blasting operation. The extent of EDZ is revealed 3.6 m-4.0 m, accounting for 28.6% of the cavern span, so it is significantly larger than rock caverns at conventional overburden depth. The rock mass mechanical response subjected to excavation and blasting is time-independent. Afterwards, based on findings of the field measurement data, a numerical evaluation method for EDZ determination considering both excavation unloading and blasting load effects is presented. The basic idea and general procedures are illustrated. It features a calibration operation of damage constant, which is defined in an elasto-plastic damage constitutive model, and a regression process of blasting load using field blasting vibration monitoring data. The numerical simulation results are basically consistent with the field measurement results. Further, some issues regarding the blasting loads, applicability of proposed numerical method, and some other factors are discussed. In conclusion, the field measurement data collected from the 2000 m-deep rock cavern and the corresponding findings will broaden the understanding of tunnel behavior subjected to excavation and blasting at great depth. Meanwhile, the presented numerical simulation method for EDZ determination considering both excavation unloading and blasting load effects can be used to evaluate rock caverns with similar characteristics.

• Journal of the Korean Geotechnical Society
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• v.20 no.5
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• pp.117-126
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• 2004

Recently, the top ＆ down method with drilled shafts as a foundation of high rise building is often adopted for the purpose of construction period reduction and construction cost effectiveness. It is common to omit the loading test as a quality assurance on account of the high capacity of drilled shafts for the top ＆ down method. It seems that the capacity of drilled shaft in recent top ＆ down method is beyond that of conventional loading test method. However, the quality assurance for the drilled shaft as foundation of high rise building becomes much more important since the drilled shaft should bear much higher working load. A small scale test pile can be an alternative as a quality assurance for the drilled shaft with hish capacities. Through a case study, this paper gives an idea for solving the limitation of the conventional loading test method for the quality assurance of drilled shaft with high capacities. In particular, this paper analyzed the scale effect for a small drilled shaft installed into bedrock, which could be used for an alternative.

• Journal of the Korea Institute of Building Construction
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• v.7 no.2 s.24
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• pp.85-92
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• 2007

In the past, recycled aggregate was used very limitedly in low value-added areas such as the base layer of roads. However, in response to the shortage of natural aggregate, high consciousness of resource saving and changed idea on environment, the quality of recycled aggregate has been improved considerably, and the percentage of recycled construction waste is increasing every year compared to simple landfill or incineration. Recently the Act on the Promotion of Construction Waste Recycling was enacted on December 2003 for the efficient use of recycled aggregate, and the Standards for the Quality of Recycled Aggregate for Concrete (Proposal) were announced in order to use and manage recycled aggregate according to quality. According to the Standards for the Quality of Recycled Aggregate for Concrete (Proposal), it is recommended to substitute recycled coarse aggregate and fine aggregate below 30% each. However, compared to the trend of recycling, the recycling rate of aggregate is still quite low. It is because of low performance of recycled aggregate, users' lack of understanding, etc. These problems basically come from the decrease of strength of recycled concrete resulting from the use of recycled aggregate, and recycled aggregate is still considered not reliable because there have been not many cases of actual application. If the basic problem of strength decrease is solved and data on recycled aggregate is provided through actual field placing, we may maximize the use of recycled aggregate. Thus, in order to maximize the use of recycled aggregate that satisfy the recycled aggregate quality standards, the present study made a mock-up similar to real structures, evaluated its performance and examined the field applicability of recycled aggregate concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3D
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• pp.275-281
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• 2012

The aim of this study is to suggest the development direction of future space management. It is not a simple question that why people visit specific place. People visit a place for escape from routine, to learn from other people, spend a time with their friends or lover, to take a rest and get some fresh idea, to relieve stress, and for shopping. It is depend on a various visit motivation with complicated a psychological phenomenon. Visitor participate in choice a specific place by various motivation and purpose. Generally, visitor motivation accepted understanding visitor behavior and process of selected a place. Understanding that why people visit specific place can use a marketing and policy making of visit place so we need to study about visitor motivation. Data were collected through offline surveys from 501 people who have visited four survey place. Empirically analyzed the determinations of visitor motivation and estimate the place by using Ordinal Logit Model.

• Journal of Environmental Impact Assessment
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• v.17 no.4
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• pp.225-233
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• 2008

An Environmental Specimen Bank (ESB) is an archive for samples that can be used to document and assess the quality of the environment in which we live. An ESB program looks at changes in the concentration of human and environmental specimens over long periods of time through retrospective analysis of archived samples of a particular area collected at regular intervals. The idea of ESB was first proposed by German and American scientists in the early 1970s and has been established since 1979 in Germany, USA, and Japan. Korea plans to establish a National Environmental Specimen Bank (NESB) in 2010. The NESB will be able to assess and improve the quality of analytical measurements as well as to compare the past and current environmental quality as a time capsule. The concept and design for the NESB facility was developed and its Standard Operation Procedures (SOPs) are being developed based on an evaluation of ESBs and SOPs of Germany, USA, and Japan. Environmental specimens proposed for banking are based on typical representatives of every level of the food chain from each type of ecosystem that are widely distributed thus enabling comparisons between different sampling areas. Through retrospective analysis of environmental specimens, the NESB will improve the reliability of environmental monitoring, ecological risk assessment, and health impact assessment.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.3
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• pp.103-131
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• 2012

This study aimed to identify the entire lifecycle of research projects in science and technology. Specifically, it attempted to reveal major research steps and research activities from the beginning to the end of R&D projects. It also investigated information needs, source use and problems scientists encounter in each research step. In-depth interviews with 24 Korean scientists in the fields of bio- and nano-science and technology revealed five major steps of lifecycle, namely idea formation, seeking funding, experiment and analysis, output disseminations, and evaluation. We further identified specific information behaviors and salient communication and research tools in each step.

• Journal of Gifted/Talented Education
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• v.24 no.5
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• pp.733-755
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• 2014

This study aims to develop and validate Creative Problem Solving Profile Inventory (CPSPI) which is a scale to measure the creative thinking style, based on the CPS theory. For redeeming the limits of existing scales, this study developed an inventory which includes an evaluation for cognitive ability as well as cognitive preference and the stage to share an idea with others and persuade (Persuasion & communication stage). At the early stage, 7 factors (stages) and 82 items were developed and finally, 5 factors and 39 items were selected through item analysis and validation of construct validity. In conclusion, CPSPI will be used as an educational tool for self-development by knowing own's strengths and weaknesses in the creative problem-solving process, and help in displaying cooperative creativity by understanding other people and interaction, based on creative thinking profiles of group members.

• Journal of Gifted/Talented Education
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• v.13 no.2
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• pp.113-130
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• 2003

In this study, learning materials that can be applied for web-based distant learning model were developed based on the characteristics of elementary school science in which investigation skills and thinking ability are considered to be important. And the effect of students' activity in a reports on student's investigating and thinking ability was investigated. While designing diverse experimental procedures, the students had. an opportunity to improve their observation attitude and way of scientific thinking. Such improvement was possible, only because the present web-based distant learning model consists of requiring an interaction between the students and a report and evaluation system which can put together such effort. Still, it was acknowledged that, as being in lack of teacher's direct support and supervision, the present web-based distant learning model might be somewhat ineffective in guiding the students in accordance with their own characteristics. For example, the students had a tendency to maintain their basic idea and style even when their reports are individually examined and corrected in terms of the format of the report.