• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.1
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• pp.1-9
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• 2022

Fixslicing AES is a technique that omits the Shiftrows step to minimize the cost of the linear layer of Bitsliced AES, showing a 30% performance over the Bitsliced technique. However, the amount of code increases to compensate for the omitted shiftrows. Therefore, it is proposed to be divided into Semi-Fixsliced in which only half of shiftrows are omitted and Fully-Fixsliced in which Shiftrows are omitted completely. In this paper, we propose a CTR mode implementation of Fixslicing AES on RISC-V using the pre-computed table technique. By utilizing the characteristics of the CTR mode, it is possible to perform fast encryption by omitting up to the second round SubBytes from the encryption process through pre-computed up to the second round SubBytes operation. Using this technique, it was confirmed that Semi-Fixsliced has a performance of 1,345 cycles per block and a performance improvement of 7% compared to the previous performance result, and Fully-Fixsliced has a performance of 1,283 cycles per block and a performance of 9% compared to the previous performance result on 32-bit RISC-V.

• Radiation Oncology Journal
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• v.16 no.1
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• pp.27-33
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• 1998

Purpose : To improve the therapeutic results of postoperative recurrent disease and inoperable disease of stomach cancer, we used the thermoradiotherapy. We conducted a retrospective analysis of the results and compared the results of hyperthermia before radiotherapy and those of hyperthermia after radiotherapy Materials and Methods : From July 1994 to November 1996, we treated twenty patients with locally advanced stomach cancer and recurrent stomach cancer with thermoradiotherapy. We divided those patients into two groups : hyperthermia before radiotherapy group (PreRT group : 13 Patients) and hyperthermia after radiotherapy group (PostRT group : 7 patients). We performed radiation therapy with the total tumor dose of 3000-5040cGy in a traction of 180-300cGy and 5 fractions per week. Hyperthermia was performed with 8 MHz radiofrequency apparatus. PreRT group patients were treated daily for 30 minutes before the radiation therapy within the interval of ten minutes. And PostRT group patients were treated with 1-2 sessions Per week for 40-60 minutes after the radiation therapy within the interval of 10 minutes. Results : Overall response rate was $33.3\%$. This response rate appeared the same in both groups. Mean survival and 1 rear survival rate were 10.3 months and $16.5\%$. In PreRT group, mean survival and 1 year survival rate were 6.8 months and $9.0\%$, and in PostRT group, mean survival and 1 year survival rate were 7.7 months and $34\%$. There were no statistically significant difference between the prognostic factors and therapeutic results. Conclusion : The thermoradiotherapy was a safe treatment method in advanced and recurrent gastric cancer when compared with other treatment. Because the number of patients we treated was small and the follow up period was short. we were not able to draw any conclusions about the therapeutic efficacy of the sequence of radiation therapy and hyperthermia. Therefore, further clinical trials of thermoradiotherauy for stomach cancer appear to be warranted.

• Journal of The Korean Association For Science Education
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• v.41 no.1
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• pp.11-18
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• 2021

The purpose of this study is to analyze the questions generated by elementary school pre-service teachers when reading the teacher's guide for the refraction of light, and to analyze the difficulties in understanding the concept and in making instructional plans. A total of 592 meaningful questions were generated by 283 elementary school pre-service teachers after reading the teacher's guide of 'light and lens' unit in the 6th grade of the 2015 revised curriculum. Of these, 306 questions are for understanding the concept of physics and 286 are pedagogical questions. As a result of the analysis, in terms of understanding the concept of physics, the elementary school pre-service teachers encounter difficulties in understanding the concept of the 'cause' of the phenomenon suggested in the textbook, such as the cause of refraction, the reason for scattering light, and the cause of the image change depending on the focal length of the convex lens. In terms of instructional planning, it was followed by questions about how to explain concepts, questions about not being able to explain concepts to elementary school students and having to teach only phenomena, specific explanation methods for specific concepts, and experimental methods. Although the teacher's guide contains various explanations and supplementary materials to help teachers understand the concept, it can be seen that there are many elementary pre-service teachers who cannot answer questions about some concepts even after reading the guide. For concepts with a high frequency of questions, it is necessary to prepare a tutorial that is more understandable. In the instructional plan, there were many questions about teaching methods and experimental methods, so it is necessary to provide more examples and specific experimental methods for explaining concepts in the teacher's guide.

• Textile Coloration and Finishing
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• v.18 no.1
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• pp.1-9
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• 2006

Treatment of PET fabrics with alkali, chitosan and Al-mordanting has been carried out and the role of the chitosan coating in the dyeing process was clarified. The pre-treatment was effectively evaluated differences in dyeing behavior between its treated and untreated PET fabrics using wood of Caesalpinia sappan. The pre-treated on PET fabrics has been examined by SEM and evidence for the presence of chitosan sought using a air permeability test. Similar colour fastness by computer color matching(CCM) obtained on both untreated and pre-treated PET fabrics. The pre-treated PET was found to be of a deeper hue to that of its dyed untreated PET and, despite of its better colour depth, the wash fastness of the pre-treated dyeing was comparable to that of its dyed untreated PR. The application of chitosan or mordanting reveled that pre-treatment imparted to the PET additional functional groups that were available for coordination with the Brazilin.

• Journal of Korea Society of Digital Industry and Information Management
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• v.20 no.1
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• pp.75-85
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• 2024

This study explored the overall perception of teaching media from the perspective of pre-service teachers. For this purpose, reflection journals written by 138 pre-service teachers were analyzed, and positive and negative perceptions of teaching media were explored. In the reflection diary, pre-service teachers were asked to write down examples of appropriate use of instructional media and the effects of their experiences, cases of inappropriate use of instructional media, and areas requiring improvement. The main research results are as follows. First, the positive aspects of teaching media perceived by prospective teachers were that it presented examples that could help understanding, aroused curiosity to focus attention, and encouraged participation to motivate learning. Second, the negative aspects of teaching media perceived by prospective teachers include cases where the playback time of the video containing learning content is excessively long and the content of the video is unclear or is higher than the learner's level and difficult to understand. This study is significant in that it presents pre-service teachers experiences and perceptions of teaching media and their desirable use methods.

• Journal of Korean Physical Therapy Science
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• v.9 no.1
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• pp.135-141
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• 2002

The purpose of this study was to investigate the effect of exercise therapy to oldwomen's muscle strength and IADL. The result of this study were the following : 1. The elderly group showed significant difference(p<.000) on effect of grip strength between pre and post after regular exercise. 2. The elderly group showed significant difference(p<.000) on effect of back strength between pre and post after regular exercise. 3. The elderly group showed significant difference(p<.000) on effect of leg strength between pre and post after regular exercise. 4. The elderly group showed significant difference(p<.000) on effect of IADL between pre and post after regular exercise. As a result of this study, the effect of exercise training program had improved muscle strength and IADL.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.209-214
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• 2012

In this work, the reduced graphene nanosheets were synthesized from pre-exfoliated graphite flakes. The pristine graphite flakes were firstly pre-exfoliated to graphite nanoplatelets in the presence of acetic acid. The obtained graphite nanoplatelets were treated by Hummer's method to produce graphite oxide sheets and were finally exfoliated to graphene nanosheets by ultrasonication and reduction processes. The prepared graphene nanosheets were studied by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). From the results, it was found that the preexfoliation process showed significant influence on preparation of graphite oxide sheets and graphene nanosheets. The prepared graphene nanosheets were applied to the preparation of conductive materials, which yielded a greatly improved electrical resistance of $200{\Omega}/sq$.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.603-609
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• 1990

Detection and non-propagating cracks of small fatigue crack for smooth and pre-cracked specimens were examined in a carbon steel. The fretting oxide induced crack closure triggered by the roughness induced crack closure has an important role in determing the length. The fatigue limit for the with no cracks or with a short pre-crack is lower at R=-1 than that at R=0. A non-propagating crack are quite different between points near the specimen's surface and those of deepest penetration.

• Journal of Digital Convergence
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• v.1 no.1
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• pp.69-91
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• 2003

The purpose of this paper is to provide several considerations to be taken into account when institutionalizing the information security(Infosec) pre-assessment. Infosec pre-assessment is a necessary process to embed the security requirements into the information systems at the early stages in their development, resulting in more cost-effective infosec. In order to provide some institutional issues, domestic infosec assessment schemes and U.S. Infosec certification and accreditation schemes are reviewed. Also, the current status of infosec implementation in the public information systems projects is analyzed. Based on the analyses, the seven suggestions are proposed in developing and performing the infosec pre-assessment scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.485-488
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• 2005

In this paper designed available pre-amplifier to Ultrabroadband power amplifier. Designed pre-amplifier used WJ company's AM1 which frequency characteristic and noise characteristic are superior. Designed to have superior VSWR characteristic and frequency characteristic covering broadband of 100MHz ${\sim}$ 3GHz using feedback.