• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.413-422
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• 2015

Proton exchange membrane (PEM), which transfers proton from the anode to the cathode, is the key component of the proton exchange membrane fuel cell (PEMFC). Nafion is widely used as PEM due to its high proton conductivity as well as excellent chemical and physical stabilities. However, its high cost and the environmental hazards limit the commercial application in PEMFCs. To overcome these disadvantages, various alternative polymer electrolytes have been investigated for fuel cell applications. We used densely sulfonated polymers to maximize the ion conductivity of the corresponding membrane. To overcome high swelling, dipole-dipole interaction was used by introducing nitrile groups into the polymer backbone. As a result, physically-crosslinked membranes showed improved swelling ratio despite of high water uptake. All the membranes with different hydrophilic-hydrophobic compositions showed higher conductivity, despite their lower IEC, than that of Nafion-117.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1200-1205
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• 2002

Construction of Private networks is becoming easier due to the openness of telecommunication market, rapidly developing telecommunication technology. The size of existing private networks is becoming huge which resulted in surplus of capacity of the networks. These trends will generate a problem of efficient use of national telecommunication resources and which will be a factor for the structure of domestic telecommunication market which will have a big impact on the existing telecommunication carriers. Therefore, national policy of private network issues should be considered along with the national efforts for the information infrastructure, control of telecommunication market, fairness of competition, strength Power of national competition. In this paper it will be suggested that the efficient policy on the issue of domestic private network, by analyzing present situation, status quo, laws, regulation and procedure for domestic private networks and comparing it with those of U.S.A, Japan, EU.

• Journal of KIISE
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• v.42 no.11
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• pp.1339-1348
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• 2015

In a distributed system environment based on a service-oriented architecture, separate systems collaborate to achieve the goals of the entire system by using services provided other systems. A service quality violation from using one service can cause runtime system failure in the environment. The existing self-adaptation methods follow fault tolerance mechanism that responds to a failure after a service quality violation. In other words, these methods are limited to responsive action. Therefore, a service-dependability-case based self-adaptation mechanism is necessary to preserve the dependability of the self-adaptive system. This paper demonstrates that the service-dependability-case based self-adaptation mechanism is better than QoS(quality of service)-based self-adaptation with fault tolerance to preserve the dependability of the self-adaptive system. Additionally, this paper suggests a method to present and analyze service dependability by using GSN(Goal Structuring Notation) which is the existing modeling method for the presentation of assurance cases, an action mechanism adapted using an analysis result of service-dependability-cases, a methods of leveraging the service-dependability-case based self-adaptation mechanism by following the service's life cycle, and the framework architecture including the major components and the interactions between the components in the control loop of the self-adaptation process.

• The Journal of Korean Academic Society of Nursing Education
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• v.13 no.1
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• pp.95-104
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• 2007

연구목적: 고혈압환자의 효과적인 자가관리 간호중재를 개발하는데 필요한 기초자료로 혈압자가측정(self-monitoring of blood pressure)에 대한 특성, 장점, 범위 및 제한점을 파악한다. 연구방법: 1996년부터 2005년까지 PubMed에 수록된 고혈압환자의 자가관리 방법중 혈압자가측정방법이 포함된 외국의 연구를 중심으로 체계적인 고찰을 실시하였다. 전체 69개 자가관리방법을 적용한 논문 중에서 혈압자가측정이나 가정에서의 혈압측정(home monitoring)에 대한 45개 논문을 선정하여 분석하였다. 연구결과 전반적으로 혈압자가측정 방법은 고혈압환자의 혈압조절을 향상시키는 효과가 유의한 것으로 나타났다. 환자가 혈압을 자가측정한 방법에서 평균 혈압, 수축기 혈압, 맥압이 유의하게 감소한 것으로 보고되었다. 장기적 프로그램에서 혈압조절율이 향상되거나, 이완기혈압의 감소효과도 보고되었다. 혈압자가측정의 기준치는 연구마다 일치하지는 않았지만 135/85mmHg 수준이 정상혈압의 상한수준으로 제시되었다. 일부 연구에서는 가정 내 혈압측정이 24시간혈압측정을 대체하는 방법으로 추천되었다. 보다 정확한 혈압자가측정을 위해서 신뢰성 있는 혈압측정기구의 사용과 정확한 측정방법이 환자들에게 교육될 필요가 있다. 결론: 혈압자가측정은 고혈압환자의 혈압조절에 유용한 방법으로 고찰되었다. 또한 고혈압의 진단, 혈압치료와 고혈압 약물복용 행위를 향상시키는 교육적 효과도 긍정적으로 나타났다. 따라서 고혈압환자를 위한 효과적인 자기조절프로그램에 혈압자가측정법을 포함하는 것이 추천되며, 추후 한국에서 시도된 관련 연구에 관한 문헌고찰의 비교연구가 필요하다.

• The KIPS Transactions:PartA
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• v.19A no.3
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• pp.147-154
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• 2012

The higher thinking skills, such as creativity and problem-solving about a given problem, are difficult to assess and diagnose. For an accurate diagnosis of these higher thinking abilities, we need to fully observe learner's problem-solving process or learner's individual reports. However, in an online learning or virtual class environments, evaluation of learner's problem-solving process becomes more difficult to diagnose. The best way to solve this problem is through reporting by tracking learner's actions when he tries to solve a problem. In this study, we developed a module which can evaluate and diagnose student's problem-solving ability by tracking actions in MS-Office suite, which is used by students to solve a given problem. This module performs based on the learner's job history through user tracking. To evaluate the effectiveness of this diagnostic module, we conducted satisfaction survey from students who were preparing the actual MOS exams. As a result, eighty-one (81) of the participants were positive on the effectiveness of the learning system with the use of this module.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.194-205
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• 2008

The production process of construction industry is different from thing of the general manufacturing, likewise various participants make temporary teamwork for success of the project through sharing of information. But, the each role of participants is Individually changed to step in construction process stage and moreover it has complicated, entangled interests. The CM(so it called Construction Management as an abbreviation word) system was inducted for the effective management and operation of construction project. The key of the CM success depends on the cooperative relationship relation to major participants. There are lots of studies and efforts for the performance measures of the CM, however existing performance index is only measured as the viewpoint of project owner. Therefore it needs to make up for balanced view through combination of the four-way view of participants. In this study, we should search for cooperative relationship of project participants, and then we should suggest to define the difference of project in their viewpoints.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.13-23
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• 2004

Proxy signature scheme based on delegation of warrant is studied in these days. Proxy signature is a signature scheme that the original signer delegates his signing warrant to the proxy signer, and the proxy signer creates a signature on behalf of the original signer. For using this scheme, the security for Protecting from the forgeability or misuse is necessary. There are several security requirements for using the proxy signature schemes. In this paper we suggest the proxy-register protocol scheme that original signer registers to the verifier about the proxy related information. In our scheme, verifier verifies the signature that original signer creates about the proxy information and sets the warrant of proxy signer, validity period for proxy signature and some limitation. Finally, we will show the advantages of our suggestion by comparing with the previous proxy signature schemes.

• The Journal of Korean Association of Computer Education
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• v.18 no.3
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• pp.69-78
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• 2015

This study aims to analyze differences in the social presence of instructor by instructor's social intervention, the effects of the social presence of instructor on learning satisfaction, and learner characteristics related to the social presence of instructor. Data including subjects' demographic information, interactions, social presence of instructor, social presence of the course, and learning satisfaction were collected from 119 adult learners in an online university in Korea. The main findings of this study are as follows. First, the social presence of instructor was higher in the higher-aged group or active group on intranet message board than the lower-aged group or inactive group on the board. Second, instructor's social intervention increased the level of perceived social presence of instructor. However, the active group on the board has shown the highest level of perceived social presence of instructor, without instructor's social intervention. Third, there was a high correlation between instructor's social intervention and the social presence of instructor, while the variables affecting learning satisfaction were the social presence of instructor and social presence of the course. From the results of this study, it is suggested that instructors' social interventions be provided systematically for those who are not active in social interaction to enhance their learning satisfaction.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.469-478
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• 2014

To provide students an alternative image of science and scientist, we developed five lesson plans that include scientists' joy, anger, sorrow, and pleasure in their life. Through the 10 hour lessons with the five topics, we investigated the effect of our program on students' image change toward scientists, their science learning, and their career development in science field. Twenty high school students participated in our program and five of them were analyzed. The qualitative data included opinionnaire survey before and after the program, field note, video recording, students' worksheets, and interview. The science episode lessons that reflect the human side of scientists were designed in five steps. The first step is the one about imaging of scientists, the second step is the one about reading scientists' episode in their life, the third step is the one about investigating human side of scientists, the fourth step is the one about feeling sympathy in scientists' context, and the last step is the one about judging human side of scientists. Students participated in this program got to feel familiarity in scientists as well as confidence in science. By obtaining the alternative image of scientists after the class, it is expected that students will play roles of well-prepared supporters with scientific literacy.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.216-224
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• 2008

The purpose of this study was to evaluate the effectiveness of fissurotomy and double application time of acidic primer of self-etching adhesive system of acid treatment on enamel surfaces for prevention of microleakage of pit and fissure sealants. The microleakage of pit and fissure sealants was evaluated by measuring the penetration depth of methylene blue solution. Specimens were divided by 4 groups according to the method of treatment. Group I: 35% phosphoric acid etching, 20 seconds. Group II: Priming with self-etching primer, 20 seconds. Group III: Priming with self-etching primer, 40 seconds. Group IV: Priming with self-etching primer, 20 seconds, after fissurotomy. The etched pattern produced on enamel was observed using a scanning electron microscope. Obtained data were analysed statistically using Kruscal-Wallis test followed by Mann-Whitney test for comparison of groups. The results are as follows: 1. Microleakage scores of group IV priming with self-etching primer 20 seconds after fissurotomy was the lowest. 2. Microleakage scores between group II and group III were not shown significant difference. 3. Enamel for 20 seconds etching with 35% phosphoric acid was observed the most effective etching pattern. And the etching pattern on the fissure enamel with self-etching adhesive 20 seconds after fissurotomy was more prominent than group II, III only using self-etching primer.