• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.13-24
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• 2003

MPEG-4 is a standard for multimedia applications and provides a set of technologies to satisfy the needs of authors, service providers and end users alike. In this paper, we suggest a Real-time Multiple Circular Buffer (M4RM Buffer) model, which is suitable for streaming these MPEG-4 contents efficiently. M4RM buffer generates each structure of the buffer, which matches well with each object composing an MPEG-4 content, according to the transferred information, and manipulates multiple read/write operations only by its reference. It divides the decoder buffer and the composition buffer, which are described in the standard, by the unit of frame allocated to minimize the range of access. This buffer unit of a frame is allocated according to the object description. Also, it processes the objects synchronization within the buffer and provides APIs for an efficient buffer management to process the real-time user events. Based on the performance evaluation, we show that M4RM buffer model decreases the waiting time in a buffer frame, and so allows the real-time streaming of an MPEG-4 content using the smaller size of the memory block than IM1-2D and Window Media Player.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.659-667
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• 2005

A Mobile Ad Hoc Network(MANET) is a multi hop wireless network with no prepared base stations or centralized administrations, where flocks of peer systems gather and compose a network. Each node operates as a normal end system in public networks. In addition to it, a MANET node is required to work as a router to forward traffic from a source or intermediate node to others. Each node operates as a normal end system in public networks, and further a MANET node work as a router to forward traffic from a source or intermediate node to the next node via routing path. Applications of MANET are extensively wide, such as battle field or any unwired place; however, these are exposed to critical problems related to network management, node's capability, and security because of frequent and dynamic changes in network topology, absence of centralized controls, restricted usage on network resources, and vulnerability oi mobile nodes which results from the special MANET's character, shared wireless media. These problems induce MANET to be weak from security attacks from eavesdropping to DoS. To guarantee secure authentication is the main part of security service In MANET because networks without secure authentication are exposed to exterior attacks. In this paper, a multistage authentication strategy based on CGSR is proposed to guarantee that only genuine and veritable nodes participate in communications. The proposed authentication model is composed of key manager, cluster head and common nodes. The cluster head is elected from secure nodes, and key manager is elected from cluster heads. The cluster head will verify other common nodes within its cluster range in MANET. Especially, ID of each node is used on communication, which allows digital signature and blocks non repudiation. For performance evaluation, attacks against node authentication are analyzed. Based on security parameters, strategies to resolve these attacks are drawn up.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.37-46
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• 2016

Patent application as achievements from R&D institutions in public sector have quantitatively increased by expanding R&D investment for enhancing competitiveness but there have been few tangible outputs from the investment. From this reason, TLO(Technology Transfer&Licensing Organization) and its operation becomes more important to implement technology transfer and commercialization and to bring success in the related business. To get work done more efficiently and to improve utilizing products of the R&D in the TLO, this research is to draw domains and activities of TLO and establish its task systems by prioritizing activities. From literature reviews and expert interviews, we generated 6 work domains and 21 task items. Applying AHP analysis, we discriminated the relative importance from task items and analyzed its priority. The finding of this research can provide implications for TLO to increase work efficiency and improve its performance.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.163-175
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• 2016

The purpose of this study is to provide an efficient internal control system formation incentives for company and to confirm empirically usefulness of the internal accounting control system for financial institutions by analyzing whether the internal control vulnerabilities of companies related significantly to the classification and assessment of soundness of financial institutions. Empirical analysis covered KOSPI, KOSDAQ listed companies and unlisted companies with more than 100 billion won of assets which have trading performance with "K" financial institution from 2008 until 2013. Whereas non-internal control vulnerability reporting companies by the internal control of financial reporting received average credit rating of BBB on average, reporting companies received CCC rating. And statistically significantly, non-reporting companies are classified as "normal" and reporting companies are classified as "precautionary loan" when it comes to asset quality classification rating. Therefore, reported information of internal control vulnerability reduced the credibility of the financial data, which causes low credit ratings for companies and suggests financial institutions save additional allowance for asset insolvency prevention and require high interest rates. It is a major contribution of this study that vulnerability reporting of internal control in accordance with the internal control of financial reporting can be used as information significant for the evaluation of financial institutions on corporate soundness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.169-173
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• 2015

This study is to predict the life exponent by measuring, over 7 years, the insulation resistance of high-voltage cables in 22 kV operation for 13 years. We found out the lifetime index in order to determine the time-dependent trend of deteriorating performance of power cables. The insulation resistances decreased according to elapsed time. We found that: the initial measurements of the cable systems were in agreement with the deterioration properties of the Arrhenius Law. By analyzing the life curve of the cable system, we also verified that the value of the life exponent (n) in the v-t characteristics defined by Weibull distribution has values from 10 to 11. When designing the cable system, the initial value of life exponent was chosen as 9 without any grounding. We have verified that the theoretical grounding based on the design safety of n=9 was actually the best one available. In the short term, we apply our research result to the diagnosis and evaluation of the power cables. In the long run, however, we plan to reduce the cost of the installation and management of cable systems in operation at power stations.

• Korean Business Review
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• v.19 no.2
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• pp.261-274
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• 2006

Airline business operates in the 21st century within fast changing market environment and fierce competition. Management of airline companies has faced the need for vast adaptation to new trends in the growth of world economy that are cardinal changes in marketing environment due to quick development of Internet and IT, transport price competition and, as a consequence, low profit margin, diversified customer wants and needs, lack of investment needed for new aircraft equipped with the latest high tech innovations, unpredictable oil price changes, and exchange rate fluctuations. This study is aimed to evaluate the quality performance of cabin service, to analyse, further, the issues that appeared to be the most significant among customers' answers to questionnaire, to explore the relationships between these issues and customer satisfaction, to highlight the essential questions to address, and to provide some practical suggestions. The five dimensions (such as tangible, reliability, responsiveness, assurance, and empathy) were adopted to examine the relationship between the service quality and customer satisfaction of Mongolian and non-Mongolian passengers travelling by the MIAT. According to findings of analysis made with use of the SERVPERF model, it can be concluded that Mongolian travellers' satisfaction was effected by 'Tangible' and 'Responsiveness' dimensions of service quality, whereas the 'Empathy' dimension has more impact on the satisfaction of non-Mongolian.

• The Journal of Korean Academy of Sensory Integration
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• v.15 no.2
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• pp.1-21
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• 2017

Objective : The aims of the this study is to identify job characteristics, to generate job description, and additionally to investigate duty task of the job for Korean pediatric occupational therapist focused on sensory integration intervention. Methods : In the first stage, job analysis of pediatric occupational therapist focused on sensory integration intervention was performed by an advisory committee consist of the DACUM panel. Through the job analysis, job description with definition was established. In the second stage, a survey was performed for 141 pediatric occupational therapist using a questionnaire based on the job description in order to investigate importance, frequency and difficulty of duty task and task elements of the job. This process was done from May to September 2017. Results : The job definition drew from this study was 'Pediatric occupational therapist provides occupational therapy services to children and adolescents to support occupational performance and social participation including daily activities and play". Through the job description established in this study, 9 duties (consulting, evaluation, intervention plan, intervention, document, education, self-development, management, and administration), 28 tasks and 169 task elements were drew. In the survey, among the duty tasks and task elements, 'ensure physical safety' and 'perform a session' were selected as the most important task, and 'ensure safety of children, sensory integrative equipment and environment' and 'prepare a safe environment' were selected as the most important element. Conclusion : This study defined job demands and characteristics of pediatric occupational therapist who performs sensory integration intervention. It is expected that this study can be used a resource to develop and/or improve educational program related.

• Journal of the Korean Geographical Society
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• v.46 no.6
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• pp.707-723
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• 2011

The purpose of this study was to quantitatively evaluate the effectiveness of learning management systems (LMS) in the physical geography class. The study adopted the experimental design and three classes participated in this study. The first class was controlled using only classroom lectures, the second class used PPT slides along with the classroom lectures, and the third class used online video clips along with the lectures. The experiments were conducted from the Spring Semester 2007 to the Spring Semester 2008 for the introductory physical geography course. The study results showed that online learning tools help students improve academic performance and their attitudes towards the class and the instructor. Compared to simple PowerPoint slides, voice recording attached to the visual lecture slide materials enhanced students' motivation. Class lectures with lecture slides did not improve students' scores. However, when the visual materials were combined with voice recording, the number of internet access to online class materials increased, and class attendance and students' final grades were improved. Based on the results, the instructional design model that combines classroom and online learning was suggested.

• Archives of design research
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• v.17 no.3
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• pp.111-122
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• 2004

The purpose of this study are two the first is to identify the positioning of product design and analyze its functional relationship with product development, manufacturing, marketing and sales in the comprehensive competitiveness evaluation model ; and the second is to estimate the determinants of QCI(quality competitiveness index), analyze the impact of product design on QCI, and compare the aforementioned results for the seven industrial sectors and the five product patterns. For this empirical analysis, this study surveyed 400 Korean manufacturing firms during August-October 2003. The major empirical findings are summarized as follows : First, the hypothesis on the positive effect of product design on QCI is accepted at a highly significant level (p < 0.001) for all : the manufacturing sector, seven industrial sectors, and five product categories. Second, the correlation analysis and factor analysis lead to the result that the effect of product design on QCI is estimated to be relatively very low, in comparison to those of product functionality and basic performance on QCI. These findings imply that Korean manufacturing sector has been still in the prematured stage at which product design has not played an important role yet. This study concludes that product design in line with other functions (product development, manufacturing, marketing, and sales) should make a good contribution to the improvement of QCI in the future.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.79-91
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• 2008

Recently, with highly Interest In Location-Based Service(LBS) utilizing location data of moving objects, the GALIS(Gracefully Aging Location Information System) which is a cluster-based distributed computing architecture was proposed as a more efficient location management system of moving objects. In the SLDS(Short-term location Data Subsystem) which Is a subsystem of the GALIS, since the SDP(Short-term Data Processor) Master transmits current location data and queries to every SDP Worker, the SDP Master reassembles and sends query results produced by SDP Workers to the client. However, the services are suspended during the SDP Master under failure and the response time to the client is increased if the load is concentrated on the SDP Master. Therefore, in this paper, the extended SLDS was designed and implemented to solve these problems. Though one SDP Master is under failure, the other can provide the services continually, and so the extended SLDS can guarantee the high reliability of the SLDS. The extended SLDS also can reduce the response time to the client by enabling two SDP Masters to perform the distributed query processing. Finally, we proved high reliability and high availability of the extended SLDS by implementing the current location data storage, query processing, and failure takeover scenarios. We also verified that the extended SLDS is more efficient than the original SLDS through the query processing performance evaluation.