• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.733-742
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• 2002

It has been known that the host mobility feature has very significant impact on the QoS (Quality of Service), which is usually required to a real-time multimedia application. The existing QoS support mechanisms to provide the real-time services to fixed network environment, like as RSVP, are inadequate to accommodate the mobile hosts which can frequently change their point of attachments to the fixed network. So, MRSVP (Mobile RSVP) protocol has been proposed to reduce the impacts of host mobility on QoS guarantees, in which a mobile host needs to make advance resource reservations at multiple locations it may possibly visit during the lifetime of the connection. This paper proposes a dynamic dual anchor node (DDAN) architecture which integrates the MRSVP and RSVP tunnel, in addition to the Mobile IP Regional Registration protocol. By limiting the resource reserved in local area, it preserves the lower level of resource reservation, but provides approximately the same degree of QoS support as the existing MRSVP.

• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.227-236
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• 2011

IPTV(Internet Protocol Television) is one of the typical businesses which are the convergence of Broadcast and Communication. It provides broadcasting service using IP networks. Recently, IPTV service is developed to Mobile IPTV or Open IPTV. Especially, Open IPTV uses open platform so not only service providers but also general users can provide contents to other users. Open IPTV system has many content providers, so existing security solution of IPTV cannot be adopted. In this paper, we suggest user authentication and key distribution mechanism on Open IPTV. Our proposed mechanism is based on Kerberos, so it can support distribution environment such as Open IPTV. We demonstrate that proposed mechanism can guarantee secure transmission of contents and reduce the delay of user authentication on Open IPTV system compared to other authentication mechanisms. We also compare our proposal and other mechanisms in various aspects, and analyze efficiency and safety of proposed mechanism. As a result, we insist that this mechanism satisfies the security requirements for IPTV.

• Journal of the Korean Society of Child Welfare
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• no.40
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• pp.285-322
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• 2012

This study was conducted to explore the effect of family centered practice on children's self-efficacy and to verify the mediating effect of family strengths. Multiple regression analysis and Sobel test were conducted using data provided by children who participated in Children's Hope Network and their primary caretakers. The study results are as follows: First, families rated highly on their level of experience regarding family-centered practice, which show that social workers were faithful in performing family-centered practice. Second, the levels of both children's self-efficacy and family strengths increased significantly after project participation when compared to the levels measured before participation. Third, family-centered practice affected children's self-efficacy only indirectly through family strengths indicating that the level of family strengths had a complete mediating effect. Implications of these results were explored in relation to the importance of family-centered practice and measures to improve social work practice.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.33-41
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• 2009

In this paper, we propose a scheme for voice data retransmission in LR-WPAN to support the required QoS even in the severe channel error environments. In IEEE 802.15.4a, as the user data rate is supported up to 850Kbps, the voice streaming data can be transferred more easily. In this research, we study the beacon-enabled mode in IEEE 802.15.4 LR-WPAN standard with 250Kbps data rate. In the proposed scheme, special slots are dynamically assigned for retransmission of the packet that fails during a voice service, and in the severe channel error environments a time diversity is acquired. Analytical results show that the proposed scheme is more robust and achieves a much higher throughput than the previous protocol in LR-WPAN.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.3
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• pp.97-113
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• 2023

In order to generalize the social entrepreneurship model with cooperation orientation and increase the possibility of using the model, this study developed a measurement tool and tested it with 389 executives of social enterprises. For the development of the measurement tool, preliminary measurement items were formed through review of previous studies, and a questionnaire was tentatively composed of 40 measurement items in five areas through an expert panel review of the measurement items. A total of 389 questionnaires were collected by conducting a questionnaire survey targeting Korean social enterprise managers, and exploratory and confirmatory factor analysis were conducted using 375 questionnaires that could be analyzed. Five factors for 24 items were derived through exploratory factor analysis and reliability analysis. Through a series of analysis processes including primary and secondary confirmatory factor analysis, the model fit of the newly constructed social entrepreneurship research model was confirmed, and the validity and reliability of the measurement tools were verified. As a result of this study, the model fit of the social entrepreneurship model(social value orientation; innovativeness; pro-activeness; risk-taking; cooperation orientation) is verified, thereby improving the theoretical explanatory power of social entrepreneurship research and at the same time providing the basis and basis for theoretical expansion of follow-up research. The study proved the possibility of generalizing the social entrepreneurship model with added cooperation orientation, and at the same time, the measurement tool used in this study was widely used as a tool to measure social entrepreneurship theoretically and practically. In addition, it was confirmed that the cooperation orientation is manifested in corporate decision-making and activity behaviors for resource mobilization and capacity building, opportunity and performance creation, social capital and network reinforcement, and governance establishment of social enterprises.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.221-232
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• 2023

This paper presents a novel convolutional neural network (CNN)-based approach for predicting bolt clamping force in the early bolt loosening state of bolted structures. The approach entails tightening eight bolts with different clamping forces and generating frequency responses, which are then used to create a similarity map. This map quantifies the magnitude and shape similarity between the frequency responses and the initial model in a fully fastened state. Krylov subspace-based model order reduction is employed to efficiently handle the large amount of frequency response data. The CNN model incorporates a regression output layer to predict the clamping forces of the bolts. Its performance is evaluated by training the network by using various amounts of training data and convolutional layers. The input data for the model are derived from the magnitude and shape similarity map obtained from the frequency responses. The results demonstrate the diagnostic potential and effectiveness of the proposed approach in detecting early bolt loosening. Accurate bolt clamping force predictions in the early loosening state can thus be achieved by utilizing the frequency response data and CNN model. The findings afford valuable insights into the application of CNNs for assessing the integrity of bolted structures.

• The Korean Journal of Archival Studies
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• no.26
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• pp.103-149
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• 2010

Documentation strategy has been experimented in various subject areas and local regions since late 1980's when it was proposed as archival appraisal and selection methods by archival communities in the United States. Though it was criticized to be too ideal, it needs to shed new light on the potentialities of the strategy for documenting local regions in digital environment. The purpose of this study is to analyse the implementation issues of documentation strategy and to suggest the directions for documenting local regions of Korea through the application of the strategy. The documentation strategy which was developed more than twenty years ago in mostly western countries gives us some implications for documenting local regions even in current digital environments. They are as follows; Firstly, documentation strategy can enhance the value of archivists as well as archives in local regions because archivist should be active shaper of history rather than passive receiver of archives according to the strategy. It can also be a solution for overcoming poor conditions of local archives management in Korea. Secondly, the strategy can encourage cooperation between collecting institutions including museums, libraries, archives, cultural centers, history institutions, etc. in each local region. In the networked environment the cooperation can be achieved more effectively than in traditional environment where the heavy workload of cooperative institutions is needed. Thirdly, the strategy can facilitate solidarity of various groups in local region. According to the analysis of the strategy projects, it is essential to collect their knowledge, passion, and enthusiasm of related groups to effectively implement the strategy. It can also provide a methodology for minor groups of society to document their memories. This study suggests the directions of documenting local regions in consideration of current archival infrastructure of Korean as follows; Firstly, very selective and intensive documentation should be pursued rather than comprehensive one for documenting local regions. Though it is a very political problem to decide what subject has priority for documentation, interests of local community members as well as professional groups should be considered in the decision-making process seriously. Secondly, it is effective to plan integrated representation of local history in the distributed custody of local archives. It would be desirable to implement archival gateway for integrated search and representation of local archives regardless of the location of archives. Thirdly, it is necessary to try digital documentation using Web 2.0 technologies. Documentation strategy as the methodology of selecting and acquiring archives can not avoid subjectivity and prejudices of appraiser completely. To mitigate the problems, open documentation system should be prepared for reflecting different interests of different groups. Fourth, it is desirable to apply a conspectus model used in cooperative collection management of libraries to document local regions digitally. Conspectus can show existing documentation strength and future documentation intensity for each participating institution. Using this, documentation level of each subject area can be set up cooperatively and effectively in the local regions.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.520-530
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• 2021

This study conducted a meta-analysis on the variables related with case management performance in Korea. In order to do a meta-analysis, a total of 27 journals, theses and dissertations published between 1998 and 2020 were reviewed systematically. Through this process, this study calculated average effect size of each variable and explored moderator variables. This study results were as follows. First, this study identified a total of 14 individual, enviroment of institution, population variables related with case management performance. Second, the results indicated that case management performance variables which showed large effect sizes included professional capability, supervision, network, case management significance recognition, manual, agency support. Third, variables with medium effect sizes included self-efficacy, case management education, autonomy, motivation, number of conference and variables with small effect sizes included work experience, academic ability, age. Fourth, Moderator effects were identified in the field, target, publication of case management. Finally, the implications of the study findings were discussed.

• Journal of the Korean earth science society
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• v.37 no.2
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• pp.117-131
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• 2016

The purpose of this study was to compare of freshmen's cognitive frames about the 'Crisis of the Earth' upon taking the Earth science I course in high school to confirm if they reflect the goal of the curriculum reasonably. Data were collected from 67 freshmen who graduated from high school. All participants were asked to express about the 'Crisis of the Earth' in painting with explanation, then we picked meaningful units from paintings. We analyzed the words and frames presented in the paintings using the Semantic Network Analysis. Result are as follows. First, when both groups' (one that took the course vs. the other that did not take it) built their cognitive frames for the 'crisis of the Earth', they reasonably connected areas that are composed of the global environment and they understood that their relation was constantly changing by interacting each other. Second, when configuring a cognitive frame about the 'crisis of the Earth', both groups reflected the characteristics of interrelationship with human activities. In particular, the group that took the course of Earth Science I fully reflected the goal of the curriculum. It is suggested that students recognize the 'crisis of the Earth' not only from a cosmic perspective bot also from the Earth's interior since most of students have strongly connected it to the phenomenon of the Earth's interior rather than the Earth's outward symptoms. In addition, it is recommended that the Earth science curriculum put more emphasis on understanding the importance of problem-solving of the Earth's crisis.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.135-139
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• 2007

Recently Data Centric Storage (DCS) schemes are variously studied for several applications (e.g. natural environment investigation, military application systems and environmental changes monitoring). In DCS scheme, data is stored at nodes within the network by name. There are several drawbacks in the existing schemes. The first is the inefficiency of the range query processing on not considered the locality of store point. the second is the non-homogeneity of store load of each sensors in case of the sensor distribution density is non-uniformed. In this paper, we propose a novel data centric storage scheme with the sensor distribution density which satisfied with the locality of data store location. This scheme divides whole sensor network area using grid and distributes the density bit map witch consist of the sensor density information of each cell. sensors use the density bit map for storing and searching the data. We evaluate our scheme with existing schemes. As a result, we show improved load balancing and more efficient range query processing than existing schemes in environment which sensors are distributed non-uniform.