• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1207-1212
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• 2015

A vibro ripper utilizes high-frequency vibration for rock fragmentation. This concept is different from those used by other existing breakers. The gearbox-shank welded joint of a vibro ripper is a very important part. Because it delivers the vibromotive force to the tooth, it is important to predict its soundness. This study was conducted to predict the fatigue life under welding conditions. The shank materials were Hardox-Hituf and AR400, and the filler metals were CSF-71T and CSF-81T. Fatigue tests were conducted under each set of conditions. P-S-N curves are presented based on the statistical testing method recommended by JSME-S002, and a comparison is made of the results under each set of conditions. The life was estimated using a P-S-N curve.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.93-101
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• 1997

The purpose of this study is to develop a test of earth science inquiry abilities using structured items. To develop a more valid and reliable instrument factual data was used, and most of the previous studies regarding inquiry teaching method and inquiry evaluation were consulted. The model developed in this study is composed of 5 stages; recognizing problems and generating hypotheses, designing inquiry, pursuiting inquiry, interpreting data, and drawing conclusion. Also, in this study 10 science inquiry abilities; recognizing problems, generating hypotheses, controlling variables, designing experiments, performing experiments, transforming data, inferencing, predicting, conclusing, and generalizing were clearly defined. The test developed in the study, Test of Earth Science Inquiry Abilities, includes 25 multiple-choice (five-choice) items and requires testing time of 50 minutes. The content validity of items, objectivity of scoring keys and clarity of items were checked by 7 experienced specialists in science education and earth science. The developed test were investigated and revised through three field tests. According to the results of the third field trial, test reliability (Cronbach $\alpha$) was 0.62, difficulty index was 0.54 and index of discrimination was 0.35. Also, the developed Test of Earth Science Inquiry Abilities showed a correlation coefficient of 0.53 with TIPS. Therefore, the development of Test of Earth Science Inquiry Abilities using structured items satisfied the reliability and validity requirements for general assessment instruments for students' earth science inquiry abilities.

• International Journal of Highway Engineering
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• v.3 no.1 s.7
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• pp.177-184
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• 2001

A recycling agent has been manufactured on the basis of the chemical composition of reclaimed asphalt binders and virgin asphalt binders. The chemical compositions of reclaimed asphalt binders extracted from reclaimed asphalt pavements have been analyzed according to the ASTM method and the results were compared to those of virgin asphalt binder AP-3. Reclaimed asphalt binders have shown that asphaltenes was increased whereas saturates, naphthene aromatics, and polar aromatics fractions were decreased. A recycling agent made of aromatic compounds, in which its chemical composition is similar to the aromatics fraction in asphalt binders, has been produced to reduce the amount of asphaltenes in reclaimed asphalt hinders. The evaluation of the recycling agent produced was performed by testing ductility, rolling and ball softening point, penetration at $25^{\circ}C$ and viscosity at $60^{\circ}C$. It was found that, by adding the recycling agent 20% by weight to the reclaimed asphalt binders, the physical properties of reclaimed asphalt binders was recovered to the level of virgin asphalt binder AP-3.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.67-74
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• 2013

Organosolv ethanolamine pulping for oil palm empty fruit bunches(EFB) were evaluated in this study. The screen yield by the ethanolamine pulping were higher than that by the soda pulping at the same operation conditions. The higher concentration of ethanolamine solvent resulted in the higher yield and the lower contents of residual lignin. The EFB pulp fibers were the narrower in fiber width but the higher in coarseness than those of the hardwood pulp fiber, while the fiber length of the EFB pulp fiber were similar to that of the hardwood fiber. The intrinsic zero span tensile testing showed the EFB pulp fiber by the 80% ethanolamine pulping were the stronger than the fiber by the soda pulping. The results of this study supported that the ethanolamine pulping could be used as an alternative pulping method for the EFB.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.2
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• pp.231-242
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• 2013

Recently, automated software testing methods such as fuzzing have been researched to find software vulnerabilities. The purpose of fuzzing is to disclose software vulnerabilities by providing a software with malformed data. In order to increase the probability of vulnerability discovery by fuzzing, we must solve the test suite reduction problem because the probability depends on the test case quality. In this paper, we propose a new method to solve the test suite reduction problem which is suitable for the long test case such as file. First, we suggested the length of test case as a measure in addition to old measures such as coverage and redundancy. Next we designed a test suite reduction algorithm using the new measure. In the experimental results, the proposed algorithm showed better performance in the size and length reduction ratio of the test suite than previous studies. Finally, results from an empirical study suggested the viability of our proposed measure and algorithm for file fuzzing.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.3
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• pp.378-395
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• 1994

The purpose of this study was to investigate the effect of various metal surface treatments and adhesive systems on the flexural bond strength of composite resin to Au-Ag-Cu-Pd alloy. The specimens were divided into nine groups by the combinations of surface treatment methods and adhesive systems. The types of surface treatment in this study were alumina blasting only, alumina blasting-Sn plating, alumina blasting-heating and three kinds of adhesive system used in this study were Silicoater system(Heraeus Kulzer GmbH,Germany), Superbond C & B(Sun Medical Co.,Ltd.,Japan) and Cesead opaque primer(Kurary Co.,Ltd.,Japan). After surface treatments and adhesive systems were applied, each specimen was built up with Dentacolor composite resin (Heraeus Kulzer GmbH,Germany). Four-point flexural bond strength was measured by Instron universal testing machine (Model 4301,U.S.A.) and modes of failure were observed by SEM(JEOL,SSM-840A,Japan). The obtained results were as follows: 1. The group that was bonded with Superbond C & B after alumina blasting-heating shelved the highest bond strength with significant difference among the groups, except the group with Cesead opaque primer after alumina blasting-Sn plating(P<0.05). 2. In the groups bonded with Cesead opaque primer, there was significant difference only in the bond strength between the alumina blasting-Sn plating group and alumina blasting group, where the former showed a higher bond strength(P<0.05). 3. In the groups bonded with Silicoater system, there were no significant differences in bond strength regardless of the surface treatment method(P<0.05). 4. In SEM evaluation, the groups of high bond strength, especially bonded with Superbond C & B after alumina blasting-heating and Cesead opaque primer after alumina blasting-Sn plating, revealed mainly cohesive-adhesive failure, whereas the others showed the tendency of adhesive failure.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.203-210
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• 2005

The penetration and viscosity tests have been used for the evaluation of the aged asphalt binder performance change. The improved test method has been required because the conventional tests could not evaluate the viscoelastic characteristics and the real behaviour of the aged asphalt binder. The conventional test methods using a different short term aged asphalt binder were tested and the test results were expressed as the penetration index and the residual penetration. The oscillatory and rotational mode tests were performed to find out the rheological characteristics of the short term aged asphalt binder in this study. The test results showed that the change of testing frequency, the speed of the vehicle effects the complex modules and phase angles. The creep compliance and shear viscosity also showed the different test results when the short term aged asphalt binders were tested. The rheological behavior should consider when the pavement design is conducted.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.469-472
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• 2008

As a general rule, concrete has higher compression strength than bending and toughness. but Ductile fiber reinforced cementitious composite has high toughness property owing to adding a large volume fiber. Therefore uniaxial tensile strength test is imperative to evaluate high toughness property of ductile fiber reinforced cementitious composite in comparison with general concrete test. but in testing compression strength, Result is different by factor of thickness, shape and edge condition. Uniaxial tensile strength test is affected by fiber's length and section area because of cementitious composite property and factor of fiber arrangement. This study evaluates toughness property of ductile fiber reinforced cementitious composite according to thickness and edge condition. The more thickness is thin, the more high performance by fiber arrangement

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.335-342
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• 2003

In order to analyze the deformational behavior accurately, the in-situ testing technique which provides the reliable deformational characteristics at whole strain ranges, needs to be developed. The pressuremeter is a unique method for assessing directly the in-situ shear modulus of soils with strain amplitude. This paper introduces a new alternative, the cavity strain measuring system in pressuremeter designed for whole strain ranges of $10^{-5}$%∼20%. Not only in the synthetic calibration chamber but also in the field, the pressuremeter tests were performed to determine the compliance of the new developed pressuremeter system. The variation in shear modulus with strain amplitude above $5\times 10^{-2}$% was reliably determined by the developed pressuremeter. It is concluded that the major cause of error in small cavity strain measuring is not from the cavity strain measuring system but from the friction between measuring arm and membrane during unloading-reloading loops.

• Convergence Security Journal
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• v.13 no.3
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• pp.71-77
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• 2013

In our country security industry biz model analysis methodology fragmentary theory exists, but it is hard to find a comprehensive analysis methodology. Biz model analysis IT companies the external factors and internal factors to integrate the information gathered about the comprehensive analysis of the development of an information system are required. Information support system early in the software architecture of the system design decisions early decision as the design, development, testing, maintenance, has a lasting impact on the project as a guideline in the development of a framework of design abstraction. BMO evaluation support information systems architecture designs system purposes. The mission must support the execution. Information system stakeholders to determine the mission and the environment. All information systems architecture shall have architecture. Technology architecture should be documented with each other can be used. Determine the architecture based architecture descriptions are presented.