• Journal of Digital Contents Society
• /
• v.13 no.4
• /
• pp.567-574
• /
• 2012

In this paper, we propose a buffering scheme to improve the performance by adaptively adjusting the length of the buffering period according to the degree of data duplication among peers that belong to each specific playback period in P2P live streaming systems. To do so, we first assign all the peers into many groups depending on their playback time positions. We then determine the length of their buffering periods according to the number of peers belonging to each group. That is, we increase the length of the buffering periods when much buffered data are duplicated among peers within a group while we decrease it when few buffered data are duplicated. By simulation experiments, we show that our proposed buffering scheme can improve the performance significantly compared to the fixed length buffering scheme that have been employed in the existing mesh-based P2P systems.

• The Journal of the Korea Contents Association
• /
• v.14 no.10
• /
• pp.20-31
• /
• 2014

Recently, cache sharing methods have been studied in order to effectively reply to user requests in mobile P2P networks. In this paper, we propose a cache sharing scheme based on a cluster considering the peer connectivity in mobile P2P networks. The proposed scheme shares caches by making a cluster that consists of peers preserving the connectivity among them for a long time. The proposed scheme reduces data duplication to efficiently use the cache space in a cluster. The cache space is divided into two parts with a data cache and a temporary cache for a cache space. It is possible to reduce the delay time when the cluster topology is changed or the cache data is replaced utilizing a temporary cache. The proposed scheme checks the caches of peers in a route to a cluster header and the caches of one-hop peers in order to reduce the communication cost. It is shown through performance evaluation that the proposed scheme outperforms the existing schemes.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.9
• /
• pp.72-80
• /
• 2019

In this task, the tool dynamometer design and manufacture, and the Ansys S/W structural analysis program for tool attachment that satisfies the cutting force measurement requirements of the tool dynamometer system are used to determine the cutting force generated by metal cutting using 3-axis static structural analysis and the LabVIEW system. The cutting power in a cutting process using a milling tool for processing metals provides useful information for understanding the processing, optimization, tool status monitoring, and tool design. Thus, various methods of measuring cutting power have been proposed. The device consists of a strain-gauge-based sensor fitted to a new design force sensing element, which is then placed in a force reduction. The force-sensing element is designed as a symmetrical cross beam with four arms of a rectangular parallel line. Furthermore, data duplication is eliminated by the appropriate setting the strain gauge attachment position and the construction of a suitable Wheatstone full-bridge circuit. This device is intended for use with rotating spindles such as milling tools. Verification and machining tests were performed to determine the static and dynamic characteristics of the tool dynamometer. The verification tests were performed by analyzing the difference between strain data measured by weight and that derived by theoretical calculations. Processing test was performed by attaching a tool dynamometer to the MCT to analyze data generated by the measuring equipment during machining. To maintain high productivity and precision, the system monitors and suppresses process disturbances such as chatter vibration, imbalances, overload, collision, forced vibration due to tool failure, and excessive tool wear; additionally, a tool dynamometer with a high signal-to-noise ratio is provided.

• Journal of Korea Multimedia Society
• /
• v.14 no.11
• /
• pp.1438-1449
• /
• 2011

UWSNs(Underwater Wireless Sensor Networks) need effective modeling fitted to the customized type of application and its covering area. In particular it requires an energy efficient data aggregation method for such customized application. In this paper, we envisage the application oriented model for monitoring the pollution or intrusion detection over a given underwater area. The suggested model is based on the honeycomb array of hexagonal prisms. In this model, the purpose of data aggregation is that the head node of each layer(cluster) receives just one event data arrived firstly and transfer this and its position data to the base station effectively in the manner of energy efficiency and simplicity without duplication. Here if we apply the existent data aggregation methods to this kind of application, the result is far from energy efficiency due to the complexity of the data aggregation process based on the shortest path or multicast tree. In this paper we propose three energy efficient and simple data aggregation methods in the domain of cluster and three in the domain of inter-cluster respectively. Based on the comparative performance analysis of the possible combination pairs in the two domains, we derive the best energy efficient data aggregation method for the suggested application.

• Journal of Korean Library and Information Science Society
• /
• v.51 no.3
• /
• pp.27-51
• /
• 2020

This study aims to propose an extended OAK metadata for research data that would be described in OAK, an open access repository of the National Library of Korea. As a research method, literature review, case studies, and interviews with related parties were conducted. The method of extending the existing OAK metadata for research data was derived as follows. First, in modeling for research data, the structure of the collection> item> file is maintained, the collection is placed as a higher group to which the research data can be grouped, and item was combined metadata and files or digital objects of various formats together. Second, by mapping the metadata standard and case organizations with the existing OAK metadata, elements judged to need to be extended to OAK for research data were selected and reflected in the existing OAK. Third, the controlled vocabulary and syntax are also proposed so that it can be used for search or later statistics through structured data. By expanding the OAK metadata to describe research data, research data produced in Korea can be officially stored and used, which is the basis for preventing duplication of research and sharing and recycling research results nationally.

• Health Policy and Management
• /
• v.24 no.2
• /
• pp.120-127
• /
• 2014

Background: Since December 2010, online computerized prospective drug utilization review (pDUR) has been implemented in Korea. pDUR involves the review of each prescription before the medication is dispensed to the individual patient. The pDUR is performed electronically by Health Insurance Review & Assessment Service (HIRA), which is a Korean governmental agency, and then HIRA provides medical institutions and pharmacies with information that can be helpful to them in preventing potential drug problems such as drug/drug interactions or ingredient duplication. The aim of this study was to assess the impact of the Korean pDUR implementation on the proportion of drug-drug interactions (DDIs) using claims data from HIRA. Methods: A before-after comparison of the prevalence of DDIs between prescription was conducted, using HIRA administrative claims data of medical institution from January 2010 to December 2011. The analysis unit was the prescription issued and pairs before and after. The main outcome measures were the proportion of DDIs within- (control group) or between- physician encounters. To examine the difference, a paired t-test was applied. Results: We found that DDIs proportion between prescription decreased significantly (t=3.04, p=0.0026) after the implementation of pDUR, whereas there is no significant reduction within prescription (t=1.15, p=0.2518). With respect to the prevalence of DDIs between drug groups, the most dramatic reduction was occurred between 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and anti-fungal agents. Conclusion: It seems effective that giving a direct feedback to prescribers by a prospective DUR. Further research is needed to assess the impact of DUR to final outcomes such as hospitalization.

• Journal of Korean Academy of Nursing
• /
• v.46 no.5
• /
• pp.619-629
• /
• 2016

Purpose: This study was a systematic review to evaluate the effects of aromatherapy on menopausal symptoms, perceived stress and depression in middle aged-women. Methods: Eight databases were searched from their inception September 8, 2015. Two reviewers independently performed the selection of the studies, data abstraction and validations. The risk of bias was assessed using Cochrane criteria. For analysis of the data, a meta-analysis of the studies was performed. Results: From the electronic databases, 73 articles were selected, and 19 removed due to duplication. After two reviewers read the abstracts of 54 studies, 34 studies were selected. Complete papers for 34 s were read and, 12 studies which met selection criteria were reviewed and the effects of aromatherapy on menopausal symptoms, stress and depression analyzed using meta-analysis with RevMan. In the 2 studies which included Randomized Controlled Trials testing of aromatherapy on menopausal symptoms and comparison of control and placebo groups were done. Aromatherapy massage was favorably effective in reducing the menopausal symptoms compared to the control group (n=118, MD=-6.33; 95% CI -11.51 to -1.15), and compared to the placebo group (n=117, MD=-4.14; 95% CI -7.63 to -0.64). Also aromatherapy was effective in reducing stress (n=72, SMD=-0.64; 95% CI -1.12 to -0.17) and depression (n=158, MD=-5.63; 95% CI -10.04 to -1.22). Conclusion: There is limited evidence suggesting that aromatherapy for middle-aged women may be effective in controlling menopausal symptoms, perceived stress and depression.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.12
• /
• pp.3885-3895
• /
• 2000

The emergence of digital imaging and digital networks has made duplication of original artwork easier. In order to protect these creations, new methods for signing and copyrighting visual data are needed. In the last few years, a large number of schemes have heen proposed for hiding copyright marks and other information in digital image, video, audio and other multimedia objects. In this paper, we propose a technique for embedding the watermark of visually recognizable patterns into the frequency domain of images. The embedded watermark can be retrieved from the decoded sequence witbout knowledge of the original. Because the source image is not required to extract the watermark, one cannot make the fake original that is invertible to watermarking scheme from the waternlarked image. In order to recover the embedded signature data without knowledge of the original, a prediction of the original value of the pixel containing the information is needed. The prediction is based on a averaging of amplitude values in a neighborhood around the pixel itself. Additionally the projxJsed technique could survive several kinds of image processings including JPEG lossy compression.

• Journal of Information Management
• /
• v.41 no.3
• /
• pp.155-173
• /
• 2010

With the advanced learning and the diversity of topics, researchers on each area keenly feel the need of precise and a quick discovery of required information at any time. This study presents a way of constructing the automatic mapping system that can compare and analyze duplicated data and that describes the result by building an effective reference extraction method and another way of correcting the wrong form of used Chinese characters with Traditional Korean Medicine dictionary. With this innovation, data duplication on references and Chinese characters errors can be fixed. Under the situation that a number of references of newly published papers that can continuously be extracted.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.12
• /
• pp.2777-2784
• /
• 2012

To support complex business environment. the enterprise information system requires prompt and flexible response to altered conditions. The development of collaboration among information systems in accordance with changes in enterprises' business environment brings about the problems of duplication of the existing business services and increase in costs of maintenance. In order to supplement and resolve such problems, researches on ontology are under way. Ontology can support the semantic interoperability of Web service by describing the resources of particular business domains and the relationships among them. This thesis suggests ontology that supports interoperability among services. The constructed ontology is designed into the service area, the meta area, and the instance area, which can support the collaboration efficiently by providing the link between the interactivity among businesses and the data. The register and call of constructed ontology are carried out with the interaction of the three areas, that is, the service area, the instance area and the meta area that supports the common elements. The efficiency of the proposed ontology is evaluated by comparing with an existing Web service ontology.