• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1311-1319
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• 1998

The methods of providing available bandwidth adaptively using feedback to maximize the utilization of network as well as the quality of service have been the focus of recent research activities for ATM(Asynchronous Transfer Mode). This study has been extended from the point-to-point connection to a point-to-multipoint environment as the number of applications requiring multicast service increases. It is known that the effectiveness of feedback based congestion control scheme diminishes as propagation delay increases. Especially for a multicast connection consisting of various paths and destinations with different performance and congestion status, the problem of unfairness due to different propagation delays may occur. The degree of such unfairness may change depending on various aspects of congestion control schemes. These has been, however, relatively little study on these problems. In this paper, we present how various aspects of control schemes-length of the interval between feedback generations, point of time to coalesce feedback cells from child paths, decreasing factor of source rate in case of congestion-affect the degree of unfairness. Simulation results show that degree of unfairness changes according to when the feedback coalescing happens. Expecially it is shown that the effect of feedback coalescing time to the degree of unfairness is more significant for the smaller feedback interval. It is also found that as the source rate decreasing factor becomes larger the average ACR(Allowed Cell Rate) at the source gets lower and the degree of unfairness grow larger.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.105-115
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• 2011

User authentication service is an absolutely necessary condition while securely implementing an IT service system. It allows for valid users to securely log-in the system and even to access valid resources from database. For efficiently and securely authenticating users, smart-card has been used as a popular tool because of its convenience and popularity. Furthermore the smart-card can maintain its own power for computation and storage, which makes it easier to be used in all types of authenticating environment that usually needs temporary storage and additional computation for authenticating users and server. First, in 1981, Lamport has designed an authentication service protocol based on user's smart-card. However it has been criticized in aspects of efficiency and security because it uses hash chains and the revealment of server's secret values are not considered. Over the years, many smart-card based authentication service protocol have been designed. Very recently, Xu, Zhu, Feng have suggested a provable and secure smart-card based authentication protocol. In this paper, first, we define all types of attacks in the smart-card based authentication service. According to the defined attacks, however, the protocol by Xu, Zhu, Feng is weak against an attack that an attacker with secret values of server is able to impersonate a valid user without knowing password and secret values of user. An efficient and secure countermeasure is suggested, then the security is analyzed.

• Cartoon and Animation Studies
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• s.40
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• pp.423-442
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• 2015

In a digital environment that is keep in change content from smart phones to tablet PC are a social network service is holding deep place in our lives. Social networking applications has building a network and communication with others than other application, it means that Social networking applications are sharing not only personal purpose in that trend of variety and competition of these social networks can be expected to trend and be developed thru analysis of user certification. this study of social network service application is proposed to developing of application thru analyze the two-effective application which is high ranked in google store. the theoretical foundation was set based on the seven elements of the social network service of the information structures designed by Jean Smith. This study proceeded analysis is for the functional elements of Facebook and Instagram, and the advantages and disadvantages through survey research. As a result of the empirical analysis to user of Instagram and face book of communication, identity, satisfaction for the group are equally. Instagram is about the presence, reputation, and Facebook has had a high level of satisfaction for each sharing and relationship. Facebook got high satisfaction from sharing features, but user feel of discomfort in the randomly showing advertising content. Instagram is not showing off advertise on common page of content, it is good point to be complementary to facebook. And, Instagram hashtag is good for convenience, but satisfaction is high with Facebook. in order to increase the satisfaction of Instagram, it is necessary to consider the main advantage of the communication and the functional aspects of the share from facebook.

• Journal of The Korean Association For Science Education
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• v.37 no.3
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• pp.429-440
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• 2017

This study investigated the influence of paired think-aloud problem solving on interactions among the pedagogical content knowledge (PCK) components considered in the processes of making written test items by pre-service chemistry teachers. The processes of making written test items using paired think-aloud problem solving in four small groups consisting of two pre-service chemistry teachers were recorded and transcribed. The analysis of the results revealed that the 'assessment in science education' of the five PCK components, regardless of the roles (solver or listener), was most frequently used in making written test items. 'Subject matter knowledge' and 'students' were also frequently used although less than the previous component. However, 'curriculum for science education' and 'instructional strategies and instruction for science education' was a little used. In the aspects of integration, the integrations between two or three components of various types were frequently found. The integrations among four or five components were also slightly found. However, the integrations of 'curriculum for science education' with the other components were less frequently found. The integrations of 'instructional strategies and instruction for science education' with other components were hardly found. The usefulness, limitations, and effective use of paired think-aloud problem solving as a strategy improving competency to make written test items and the PCK of pre-service teachers were discussed on the basis of the results.

• Journal of The Korean Association For Science Education
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• v.38 no.4
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• pp.587-598
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• 2018

In this study, we investigated the characteristics of pre-service science teachers' curriculum design for lessons using self-generated analogy. Three pre-service science teachers at a college of education in Seoul participated in this study. After a workshop on lessons using self-generated analogy, they planned and demonstrated lessons. All of the teaching-learning materials were collected, and their lessons were observed and videotaped. Semi-structured interviews were also conducted before and after their lessons. The characteristics of lessons using self-generated analogy were analyzed in the perspectives of PCK. The analyses of the results revealed that they used various strategies to promote students' generating analogies. They lacked understanding of the stages of the lessons and the role of teachers. Although all of them considered assessment, they used limited assessment methods and assessment dimensions. Some actively considered students' misconceptions, and specifically anticipated analogies that students could generate. They determined topics for lessons considering various aspects such as the level of self-generated analogy and the characteristics of scientific conceptions. On the bases of the results, we suggest some educational implications for pre-service science teacher education.

• Korean Journal of Construction Engineering and Management
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• v.16 no.3
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• pp.152-164
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• 2015

Enhancing clarity and transparency of the pricing guide for technical services for public construction works enables the prediction and reimbursement of the service cost for project owners and bidders, while it would also yield benefits for engineers who carry out the construction tasks. In order to improve the global competitiveness of construction service industry, the government revised its pricing guide for techical services for construction works recently, moving away from its previous percentage-of-construction-cost method towards the Cost Plus a Fee Method. However, since the Cost Plus a Fee Method results in the rise of the service price by 153%~197%, there is the need for a review on the method and basis of the adjustment in order to avoid controversies regarding the application of the revised method. In this context, this paper analysed the 2014 revision of the pricing guide for technical services for public construction works through comparison with foreign cases including those of the US and the UK. The analysis yielded the conclusion that, while the shift towards Cost Plus a Fee Method which is widely used in advanced economies is a very meaningful change in large measure, certain aspects still remain problematic. Unlike in advanced economies, the detailed break-down shows the direct labor cost includes certain indirect expenses. Also, indirec expenses are admitted so comprehensively as to include overhead costs and technology royalties. These problems results in redundant estimation of certain expenses, and obstructs transparency in spending details. This paper proposes various improvement measures to address these issues.

• Journal of Society of Preventive Korean Medicine
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• v.21 no.2
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• pp.45-53
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• 2017

Background and Aim : Lately the age of competition has come among the medical service area. At the same time disputes over the medical practice related to the medical person's territory tend to increase. In part it is due to the increased medical persons but in part it is because the medical practice is not defined clearly in the Medical Service Act for the practice of each medical person. So the legal definition of medical practice will be discussed here. Materials and Method : The cases from the court have been confirmed the difference between the two medical persons regarding the actual events. Legal aspects of medical practice in Korean medicine and the related cases will be reviewed and analysed. Results : The form of medical practice consists of administrating Korean medicine treatment and providing guidance for health based on Korean medicine. For medical doctors the practice includes medical treatment and guidance for health. Circular definition in the Medical Service Act over the medical practice, medical person and medical instruments makes it difficult to understand the whole idea. Therefore, the court has a tendency to decide the medical practice of medical doctor of Korean medicine from the some reliable points which is: 1) it is based on the principle of traditional Korean Medicine, 2) it is practiced by the medical doctor of Korean Medicine, 3) it can do harm to the patient without proper involvement of the medical doctor of Korean Medicine. Now the Act on the promotion of Korean Medicine and Pharmaceuticals makes it include the concept of "scientifically applied and developed" medical practice of Korean Medicine. Conclusions : With the essential change in the Act on the promotion of Korean Medicine and Pharmaceuticals, it is expected that even slight change can be seen in the court cases. However, still the concept of medical practice in the Medical Service Act remains the same. Modernisation of Korean Medicine, enhancement of textbooks and clinical practice training and the effort to amend the law to clearly define the medical practice of Korean Medicine will contribute to the clinical and academic environment. Evidence based Korean Medicine and even the unification of east-west medicine could be considered for the situation.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.13 no.1
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• pp.215-230
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• 2002

A braille library undoubtedly changes with a changing information environment. However "changing information service" as a topic couldn't be found among previous researches. That's the reason it felt necessary in this paper to analyze the way service in a braille library changes according to a changing environment. as well as to make clear the meaning and the role a braille library has for blind people. As a first step, a questionnaire aimed at Korean braille libraries was carried out in order to understand changes of library service. Results showed that most changes in braille library service were due to the influence of internet, directly or indirectly. In this connection. the way braille libraries made us of this new tool was analyzed as follows. Firstly braille libraries were found to help a better circulation of information from internet towards blind people. It appeared secondly that internet was also used in order to improve already existing services as well as new services. Thirdly libraries were shown to have developed new services related to internet although these services weren't initially library ones. These new aspects of library service constitute by themselves a proof of the importance of braille libraries, although blind people might in some cases obtain the wished piece of information without them. Therefore braille libraries prove to be remained necessarily even if information environment changes.t changes.

• Journal of The Korean Association For Science Education
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• v.36 no.5
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• pp.769-781
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• 2016

This study investigated the interactions among the PCK components of pre-service secondary chemistry teachers considered in the processes of making written test items individually and in small groups. The processes of making written test items individually for 8 pre-service teachers was studied through the think-aloud method. The analysis of the results revealed that the 'assessment in science education' of the five PCK components was most frequently used in making test items. 'Curriculum for science education,' 'subject matter knowledge,' and 'students' were also frequently used although fewer than the previous component. However, 'instructional strategies and instruction for science education' was hardly used. The integrations between two or three components with various types were frequently found. However, integrations among four to five components were not found. The processes of making written test items in two small groups consisting of four pre-service teachers were observed. The analysis of the results revealed that the PCK components used in small groups were similar to those in the individual processes. However, 'curriculum for science education' was less frequently used, and the numbers of subcategories used at a relatively high frequency increased from other four components in small groups. In the aspects of integration, the proportion of the integrations between two components decreased and that for three components increased compared with those in the individual processes. The integrations among four or five components were also newly found. However, the integrations of 'curriculum for science education' with the other components were less frequently found. The integrations of 'instructional strategies and instruction for science education' with other components were still hardly found.

• Cross-Cultural Studies
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• v.43
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• pp.405-428
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• 2016

The purpose of this paper is to examine the narrative-building method and the post-historical descriptive aspects of the movie Paradise in Service, which deals with the modern history of Taiwan. Although Paradise in Service tells the history of a certain time period, it focuses on the anguish and agony felt by people who lived during that age rather than on the meaning of historical events or interpretation of the past in terms of official historical discourse. That is, as it avoids looking at the present by composing a narrative in the descriptive historical context and from bearing weight from the viewpoint of realism, it gains the possibility of establishing a new field of discourse through a post-historical discussion using descriptive historical texts. However, the movie tries to create fantasy through a special type of licensed prostitution as a means of post-historical description. In other words, when this movie tries to reproduce the microscopic history of common people in trouble because of a historical tragedy, it considers only men and excludes "weak" women. Thus, although Paradise in Service has meaning in that it gives an example of how movies can disrupt official historical discourse and group memory and rewrite history by focusing on individuals, it is limited by its male-centrism.