• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.4
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• pp.1153-1170
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• 2012

Multimedia computing has attracted considerable attention with the rapid growth in the development and application of multimedia technology. Current studies have attempted to support the increasing resource consumption and computational overhead caused by multimedia computing. In this paper, we propose $MediaCloud$, a new multimedia computing paradigm that integrates the concept of cloud computing in handling multimedia applications and services effectively and efficiently. $MediaCloud$ faces the following key challenges: heterogeneity, scalability, and multimedia Quality of Service (QoS) provisioning. To address the challenges above, first, a layered architecture of $MediaCloud$, which can provide scalable multimedia services, is presented. Then, $MediaCloud$ technologies by which users can access multimedia services from different terminals anytime and anywhere with QoS provisioning are introduced. Finally, $MediaCloud$ implementation and applications are presented, and media retrieval and delivery are adopted as case studies to demonstrate the feasibility of the proposed $MediaCloud$ design.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5058-5077
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• 2019

Traditional regenerating codes are designed to tolerate node failures with optimal bandwidth overhead. However, there are many types of partial failures inside the node, such as latent sector failures. Recently, proposed regenerating codes can also repair intra-node failures with node-level redundancy but incur significant bandwidth and I/O overhead. In this paper, we construct a new scheme of regenerating codes, called IR-RBT codes, which employs intra-node redundancy to tolerate intra-node failures and serve as the help data for other nodes during the repair operation. We propose 2 algorithms for assigning the intra-node redundancy and RBT-Helpers according to the failure probability of each node, which can flexibly adjust the helping relationship between nodes to address changes in the actual situation. We demonstrate that the IR-RBT codes improve the bandwidth and I/O efficiency during intra-node failure repair over traditional regenerating codes but sacrifice the storage efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.648-651
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• 2002

In data broadcast environments, data is disseminated from a small number of sewers to a much larger number of clients. The advancing technology of hardware and increasing needs of users' have extended a broadcast environments. A mobile environment use the data broadcasting. A user carrying a portable computer can submit the operations of a transaction. Some limitations such as the poor-resource, user mobility, and low bandwidth are difficult to apply traditional transaction management to the mobile environments. So, the new mechanisms are needed and one of the them is the correctness criteria of transactions. Serializability is the most used criteria, but serializability is not appropriate to the broadcast environment because unnecessary abort and additional message exchanges are occurred. Hence, in this paper, we will address the need of the new correctness criteria weaker than serializability and describe the adoption of the update consistency.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.513-522
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• 2016

We propose a mechanism for monitoring load in quality of service (QoS)-enabled wireless networks and show how it can be used for network management as well as for dynamic pricing. Mobile network traffic, especially video, has grown exponentially over the last few years and it is anticipated that this trend will continue into the future. Driving factors include the availability of new affordable, smart devices, such as smart-phones and tablets, together with the expectation of high quality user experience for video as one would obtain at home. Although new technologies such as long term evolution (LTE) are expected to help satisfy this demand, the fact is that several other mechanisms will be needed to manage overload and congestion in the network. Therefore, the efficient management of the expected huge data traffic demands is critical if operators are to maintain acceptable service quality while making a profit. In the current work, we address this issue by first investigating how the network load can be accurately monitored and then we show how this load metric can then be used to provide creative pricing plans. In addition, we describe its applications to features like traffic offloading and user satisfaction tracking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.241-269
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• 2012

Wireless networks composed of multimedia-enabled resource-constrained sensor nodes have enriched a large set of monitoring sensing applications. In such communication scenario, however, new challenges in data transmission and energy-efficiency have arisen due to the stringent requirements of those sensor networks. Generally, congested nodes may deplete the energy of the active congested paths toward the sink and incur in undesired communication delay and packet dropping, while bit errors during transmission may negatively impact the end-to-end quality of the received data. Many approaches have been proposed to face congestion and provide reliable communications in wireless sensor networks, usually employing some transport protocol that address one or both of these issues. Nevertheless, due to the unique characteristics of multimedia-based wireless sensor networks, notably minimum bandwidth demand, bounded delay and reduced energy consumption requirement, communication protocols from traditional scalar wireless sensor networks are not suitable for multimedia sensor networks. In the last decade, such requirements have fostered research in adapting existing protocols or proposing new protocols from scratch. We survey the state of the art of transport protocols for wireless multimedia sensor networks, addressing the recent developments and proposed strategies for congestion control and loss recovery. Future research directions are also discussed, outlining the remaining challenges and promising investigation areas.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1717-1732
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• 2015

The widespread use of location-based services (LBSs), which allows untrusted service provider to collect large number of user request records, leads to serious privacy concerns. In response to these issues, a number of LBS privacy protection mechanisms (LPPMs) have been recently proposed. However, the evaluation of these LPPMs usually disregards the background knowledge that the adversary may possess about users' contextual information, which runs the risk of wrongly evaluating users' query privacy. In this paper, we address these issues by proposing a generic formal quantification framework,which comprehensively contemplate the various elements that influence the query privacy of users and explicitly states the knowledge that an adversary might have in the context of query privacy. Moreover, a way to model the adversary's attack on query privacy is proposed, which allows us to show the insufficiency of the existing query privacy metrics, e.g., k-anonymity. Thus we propose two new metrics: entropy anonymity and mutual information anonymity. Lastly, we run a set of experiments on datasets generated by network based generator of moving objects proposed by Thomas Brinkhoff. The results show the effectiveness and efficient of our framework to measure the LPPM.

• International Journal of Contents
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• v.11 no.2
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• pp.63-68
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• 2015

A citation analysis utilizes the relations among citations and is the most popular bibliometric method. This analysis is based on 1) the evaluation by paper, journal and researcher of the research output, 2) the identification of emerging research topics, 3) the production of a map of the intellectual structure of the research domain and 4) various services for academic information. However, this approach has a limitation in that a citation is treated in a very simple manner, even though the purpose of citation can vary greatly. To address this problem, new approaches have been studied that take into account the citation context. This research separates the citations according to the citation functions and tries to conduct an analysis according to the newly classified citations. Furthermore, research on the citation summarization and visualization based on both the citation context and the citation function of the citations was also attempted. However, since there are very few studies related to citation context in South Korea, more research and development is needed in this area. This study analyzes the status of the research in terms of the citation context. For this, we utilized social network analysis methods.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.186-192
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• 2021

Recently, the demand for more precise and demand-oriented customized spatial information is increasing due to the 4th industrial revolution. In particular, the use of 3D spatial information and digital twins which based on spatial information, and research for solving social problems in cities by using such information are continuously conducted. Globally, non-face-to-face services are increasing due to COVID-19, and the national policy direction is also rapidly progressing digital transformation, digitization and virtualization of the Korean version of the New Deal, which means that 3D spatial information has become an important factor to support it. In this study, physical objects for cities defined by world organizations such as ISO, OGC, and ITU were selected and the target of the 3D object model was limited to buildings. Based on CityGML2.0, the data collected using a drone suitable for building a 3D model of a small area is selected to be updated through road name address and building ledger, which are administrative information related to this, and LoD2.5 data is constructed and urban space. It was intended to suggest an object update method for a 3D building among data.

• International Journal of Knowledge Content Development & Technology
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• v.12 no.4
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• pp.25-39
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• 2022

Perceptions of Library and Information (LI) professionals in Nigeria and the impact of COVID-19 on libraries, librarians and library services, were studied. The significance of demographic factors on LI professionals' perception of COVID-19 and its impact on libraries was tested. Descriptive survey design and Purpose sampling technique were adopted. LIS professionals in Nigeria constituted the population, and an online questionnaire designed by the researchers through Microsoft Forms was used. Descriptive analysis of respondents' demographic data and their covid-19 perception were presented in frequencies and percentages using tables while multivariate regression technique was used to test the significance of relationship between variables at P < 0.05. Findings revealed that many (61.4%) of the respondents agreed that COVID-19 is real but have personal reservations. However, 47.5% indicated that COVID-19 is a scientific invention. On the impacts of COVID-19 on libraries, the study found that COVID-19 is a game changer that will enhance the creation of new services by libraries, cause the reconfiguration of library space for safe operations in post-COVID, establishment of new rules and regulations, and more reliance on e-resources. On the test of association, educational qualification of respondents had a significant impact on respondents' perceptions that COVID-19 will reduce the use of library print resources (P-value = 0.005, B: 0.38, [95% CI: 0.115 - 0.646]) and that library will create new services to address the changes caused by COVID-19. Also, educational qualification of respondents significantly influenced respondents' perception that COVID-19 is real. The study recommends that libraries should take advantage of the season to innovate, and that public health institutions should continually educate people on corona virus to disabuse people's mind of conspiracy theories.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.85-93
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• 2020

The paper investigates the impact of the statement of cash flows of listed companies on lending decisions of commercial banks in the context of Vietnam. Survey data for the research were collected from 160 credit officers of Vietnamese commercial banks for short-term and long-term lending decisions, whether the cash flow statement includes complete information or has a lack of information. The cash flow statement, in which the information on the cash flow is completely contrary to the profit information on the income statement is examined. This paper employed T-tests to address the research issues in a market considered to be ineffective, like Vietnam. The research results show: (1) the information on the cash flow statement affects both the short-term and long-term lending decisions of credit officers, and (2) the lack of information on the cash flow statement in both cases of positive and negative profits affects the comfort and confidence of credit officers in making decisions. The research findings also indicate that cash flow statements are important for lending decisions of credit institutions in Vietnam. Therefore, this paper provides a new insight to managers on how to improve the quality of cash flow statement to meet the needs of lenders.