• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.426-436
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• 2011

In the past, ERP had been applied to large company mainly, but recently, in order to exist from global business environment, most of smaller businesses are using or planing to introduce ERP. However, introduction of ERP requires considerable expense and effort, before ERP come into being, it is needed to measure the expense of introducing and the outcome expected. Previous analytical frameworks (according to introduction of ERP) have been focused on measuring improvement of performance by introducing ERP. This study carries out a survey on priority analysis of information system with small businesses which produce displayer parts. To derive the user's priorities which have been disregarded beside the improvement of performance on information system, this study rearranges the analysis indices by using BSC model and it analyzes the priorities of importance according to the stakeholder(manager group, middle manager group, worker group) by using ANP method.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.25-34
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• 2009

Many conference systems over the Internet require authenticated group key agreement (AGKA) for secure and reliable communication. After Shamir [1] proposed the ID-based cryptosystem in 1984, ID-based AGKA protocols have been actively studied because of the simple public key management. In 2006, Zhou et al. [12] proposed two-round ID-based AGKA protocol which is very efficient in communication and computation complexity. However, their protocol does not provide user identification and suffers from the impersonation attack by malicious participants. In this paper, we propose improved ID-based AGKA protocol to prevent impersonation attack from Zhou et al.'s protocol. In our protocol, the malicious insider cannot impersonate another participants even if he knows the ephemeral group secret value. Moreover, our protocol reduces the computation cost from Zhou et al.'s protocol.

• Journal of the Korea Computer Industry Society
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• v.3 no.9
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• pp.1235-1244
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• 2002

This paper proposes a group key management protocol for a secure of all the multicast user in PIM-SM multicast group communication. With prosed architect, subgroups for multicast secure group management will be divided by RP (Rendezvous-Point) unit and each RP has a subgroup manager. Each subgroup manager gives a secure key to it's own transmitter md the transmitter compress the data with it's own secure key from the subgroup manager. Before the transmitter send the data to receiver, the transmitter prepare to encrypt a user's service by sending a encryption key to the receiver though the secure channel, after choking the user's validity through the secure channel. As the transmitter sending a data after then, the architecture is designed that the receiver will decode the received data with the transmitter's group key. As a result, the transmitting time is shortened because there is no need to data translation by group key on data sending and the data transmition is possible without new key distribution at path change to SPT (Shortest Path Tree) of the router characteristic. Additionally, the whole architecture size is samller than the other multicast secure architecture by using the conventional PIM-SIM routing structure without any additional equipment.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.6
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• pp.51-59
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• 2016

Recently the company is getting bigger and has many employees. Therefore, sometimes, the uniform internal marketing devices for whole employees are inappropriate because they are different demographic aspects. To find efficient internal marketing factors, this paper analyzes empirically the determinants of employee's satisfaction to their firm, by group based demographic aspects(male and female : 2 groups, ages : 3 group, employment period : 3 groups), for a insurance claim adjuster company As a result, it is found that the psychological factor has the statically significant determinant in all the 8 groups, with biggest positive coefficient in the 7 groups. Other factors, such as the organizational factor, the individual factor and spatial factor are statically significant determinant depending on the groups differently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1119-1127
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• 2012

The one of features of M2M communications, which are recently attracted attention as a future business of mobile communications, is that there is a large number of devices compared with traditional communication services. Hence, the control signal that are generated by the M2M devices may cause a significant congestion in the network and in order to solve this problem, a standardization is progressing for reducing the redundant signaling by managing M2M devices as a group in 3GPP standardization. In this paper, we propose a method of group based mobility management by managing M2M devices that have the same mobility as a group. In the proposed method, M2M devices that have the same mobility are grouped by the Mobility Management Entity (MME) and the MME elects a group header among the M2M devices in the group. Then, the group header performs the Tracking Area Update (TAU) on behalf of the group members to reduce the signaling overhead of mobility management. With the proposed method, we can achieve 80% decrease of the signaling overhead of mobility management compared with the case where each M2M device individually performs its TAU procedure.

• Journal of KIISE
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• v.43 no.7
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• pp.786-794
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• 2016

Recommender systems can be used to assist users in selecting required services for their tasks in Internet of Things (IoT) environments in which diverse services can be provided by utilizing IoT devices. Traditional research on recommendation mainly focuses on predicting preferences of individual users. However, in IoT environments, not only individual users but also groups of users can access services in the environments. In this study, we analyzed user groups' preferences on services and developed service recommendation approach for new groups that do not have a history of accessing IoT-services in a certain place. Our approach extends the traditional user-based collaborative filtering by considering the similarity between user groups based on their member organization. We conducted experiments with a real-world dataset collected from IoT testbed environments. The results demonstrate that the proposed approach is effective to recommend services to new user groups in IoT environments.

• Communications of Mathematical Education
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• v.23 no.4
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• pp.1043-1058
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• 2009

This study concerns with the effects of group projects performed by the students in college math classes. The study result shows that 61% of the students get more self-confidence and interest in mathematics through working projects. In addition, the result reveals that one of the essential factors for successful college mathematics class is to provide a strong motivation for learning to students. For effective teaching through group projects, this paper suggests that 1) the number of students in the class be 20 or less, 2) the projects group be consisted of two members, 3) the instructor should select proper problems to students' level from extra-textbooks, 4) the problems should be interesting, positive and challenging, 5) each group should take only one problem, 6) the groups be provided with enough references and materials, 7) each student in the group be cared to feel importance and necessity of mathematics and cooperative work, 8) the students should work with math joyfully, 9) the instructor remind the students that we live with mathematics in real life, 10) 2-month be a necessary and appropriate term in working projects.

• Digital Contents
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• no.4 s.59
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• pp.64-66
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• 1998

일본 온라인 정보검색 그룹회는 1979년 10월에 설립된 정보검색 이용자 단체로 온라인상에서 제공되고 있는 정보를 어떻게 효율적으로 사용할 수 있는가를 연구하는 모임으로 정보검색에 관심이 있는 회사원과 공무원 등 대부분 연구, 조사 분야의 사람들이 회원으로 가입돼 있다. 특별히 검색교육을 위한 교사가 따로 구성되어 있는 것은 아니고 오랜 경험을 통해 터득한 관련 지식을 다른 회원들에게 가르쳐 주는 연구회의 성격을 가지고 있다.

• Journal of KIISE:Information Networking
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• v.27 no.3
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• pp.348-359
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• 2000

Most of the important real time multimedia applications require multipoint transmissions. To support these applications in ATM based Intermet environments, it is important to provide efficient IP multicast transportations over ATM networks. IETF proposed MARS(Multicast Address Resolution Server) as the service architecture to transport connectionless IP multicast flows over connection oriented ATM VCs. MARS assumes UNI3.0/3.1 signalling. Since UNI3.0/3.1 does not provide any means for receivers to request a join for a multicast ATM VC, MARS provides overlay service to relay join request from IP multicast group members to the sources of the multicast group. Later on, ATM Forum standardized UNI4.0 signalling which is provisioned with a new signalling mechanism called LIJ(Leaf Initiated Join). LIJ enables receivers to directly signal the source of an ATM VC to join. In this paper, we propose a new service architecture providing IP multicast flow transportation over ATM networks deploying UNI4.0 signalling. The proposed architecture is named UNI4MARS. It comprises service components same as those of the MARS. The main functionality provided by the UNI4MARS is to provide source information to the receivers so that the receivers may exploit LIJ to join multicast ATM VCs dynamically. The implementation overhead of UNI4MARS and that of MARS are compared by a course of simulations. The simulation results show that the UNI4MARS supports the dynamic IP multicast group changes more efficiently with respect to processing, memory and bandwidth overhead.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6076-6083
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• 2014

Service recovery research has been conducted on the premise that service problems can be returned to the original condition. This study, however, focused on irrecoverable service problems for the first time and classified them according to the types and sub-types. The specific wants of customers who experienced unrecoverable service problems were identified by analyzing the customers' emotion, behavior pattern, and the company's responses. The results revealed three main types of problems and 2 categories in group 1, 6 categories in group 2, and 2 categories in group 3. In particular, damaged items and bodily harm were frequent problems, and bodily harm was recognized as the most severe failure. Regarding the customers' emotion, the customers were so enraged at the audacity and the company still showed many problems in terms of its response to the service failures. This study also suggested the analysis results of the customers' behavior and company evaluation.