• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.223-228
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• 2008

Recently, various types of wireless access networks, such as WLAN, WiBro and HSDPA, etc, have been successfully deployed by commercial service providers (i.e., KT, KTF). In this situation, there are many efforts to provide high quality of services to guarantee seamless mobility between heterogeneous networks. The IP layer mobility protocols are efficient mechanisms to provide seamless mobility between IP based heterogeneous networks as well as homogeneous networks. However, to apply IP mobility protocols in real heterogeneous networks (i.e., WiBro and HSDPA), we must consider not only the basic features of techniques of wireless access networks (i.e., Data rate, Coverage, Quality of Service) but also the problem of real environment of service provider (i.e., Expanse cost to change the access network). Due to this reason, it is difficult to satisfy required conditions by using only one IP mobility protocol in real heterogeneous networks. Therefore, in this paper, we propose an efficient mobility protocol to solve the complex problems that are occurred in real heterogeneous networks. The proposed protocol, so-called, "Hybrid Mobile IP" tries to provide a synergy effect by integrating Client Mobile IPv4 (CMIPv4) and Proxy Mobile IPv4 (PMIPv4), and using the two mobility protocols selectively according to the situation of real heterogeneous networks.

• Journal of KIISE:Databases
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• v.36 no.2
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• pp.123-138
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• 2009

In recent years, the web services composition search has become an issue of great interest. The web services composition search is the process of integrating individual web services to yield desired behavior. Through the web services composition search, more sophisticated functionalities can be provided. Current solutions can be classified into three main classes: forward chaining approach, backward chaining approach and two-phase approach. However one-way chaining approaches, such as forward chaining approach and backward chaining approach have limitations of searching irrelevant web services. And two-phase approach has limitations of including redundant web services. In this paper, we propose an unredundant web services composition search based on the two-phase algorithm. The algorithm consists of a forward phase and a backward phase. In the forward phase, the candidate web services participating composition will be found efficiently by searching the Link Index. In the backward phase, unredundant web services compositions will be generated from candidate web services by using the Token Manager. The experimental results show that our proposed algorithm is more efficient than one-way chaining approaches. The experimental results also show that our algorithm can provide more solutions than previous two-phase approach and is comparable to previous one in execution time.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.4
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• pp.334-348
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• 2005

The goal of next generation digital broadcasting is offering the interaction among consumers and providers as well as variety services. One of the important factors for this new broadcasting environment keeps the interoperability among providers and consumers since the environment is distributed. Therefore a standard metadata for digital broadcasting is required and TV-Anytime metadata is one of the metadata standards for digital broadcasting. The terminal nodes of TV-Anytime metadata are defined by using MPEG-7 metadata. MPEG-7 metadata is standard metadata for describing multimedia content. Therefore, if we use the MPEG-7 metadata for describing broadcasting content can offer multimedia search services like content-based search by the extension of metadata. The efficient management system for these metadata is important for offering the services with high Duality on real broadcasting environment TV-Anytime metadata and MPEG-7 metadata are technically defined using a single XML schema, so its instances are XML data. Currently, a lot of systemsfor managing XML data are proposed in many researchers and we can expect to adapt these systems for managing broadcasting metadata. But the methods used in these systems are not specific methods for managing broadcasting metadata because of methods for general-purpose. In this paper, we find the properties of broadcasting metadata and develop an efficient metadata management system that is based on the found properties. Since our systemis implemented on real broadcasting environment, we expect that the system is most efficient and suitable. Also our system is interoperable since we use XQuery as query language for querying broadcasting metadata.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.699-708
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• 2002

Since various terminals and different networks get involved in playing of a multimedia presentation, the case that the presentation QoS at a destination should be different from the QoS of multimedia data at a source occurs frequently. For playing the multimedia presentation, the multimedia data at a source should be transcoded into the multimedia data satisfying the QoS required at the terminal. The problem of generating the transcoding path is that, for a given multimedia presentation, different transcoding paths depending the terminal and networks should be generated. That is, a fixed transcoding path cannot be applied to a multimedia presentation. Instead, whenever the terminal and network to play the presentation get determined, a proper transcoding path should be regenerated automatically. In this paper, the algorithm for generating the transcoding path and the method for checking the playability of the generated path are proposed. The generating algorithm adopted the technique of Context Free Grammar in describing the set of transcoding resources and a user's transcoding rules in order to utilize the well-known compiler techniques. For the playability check, a method of computing the transcoding time and the delay time between data units are proposed. Finally all the proposed methods were implemented in the stream engine, called Transcore and the presentation-authoring tool, called VIP, we had developed. And the test results with a sample scenario were presented at the last.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2603-2608
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• 2015

Mushroom is a high in protein, low calorie food and has dietary fiber, vitamins, iron and minerals such as zinc. It is called that mushroom is one of the biggest concerns for healthy foods. When we make the artificial cultivation of mushroom, one of the greatest influence element is temperature. In this regard, farmers passively measure temperatures in the greenhouse as inaccurate way such as by the naked eyes. In this paper, we constructed a display system in order to improve the efficiency of manual management of temperature based on the influence of temperature on the mushroom. In related to the methods of mushroom cultivation, the recent technology apply the new technology such as sensors and IT convergence services. And then cultivating mushroom is managed effectively. In this paper, we implement an automatic display system for sensing data. By using this function, farmers could effectively manage environment needed to be grown mushroom, and anticipate the improvement of sales by increasing quality of mushrooms as well.

• Information Systems Review
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• v.5 no.2
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• pp.109-129
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• 2003

This study is intended to examine how strategic nature of the alliaTnce, characteristics of input resource, communication activities will affect the strategic partnership(trust/commitment) and performance in the strategic alliance between internet shopping mall and the third party logistics. The variables affecting the partnership(trust/commitment) between internet shopping mall and the third party logistics produced the result to prove what I intend to suggest in this study, in verifying four hypotheses such as strategic importance, complementation of resource, quality of communication, share of information. It was found that the partnership have a significant positive influences on the performance of strategic alliance. As most of the domestic Internet shopping malls employ the third party logistics strategically, the implications from this study are as following: First, this study attempts to find out factors influencing partnership(trust/commitment) and the performance of strategic alliances. Second, the results that strategic partnership can build up based on the long term thrust and commitment implies operation and management are important during operation of strategic alliance. Third, this study provides the model of determinants of partnership and performance in the strategic alliance for logistics services which is one of the factors consumers in the Internet shopping mall are most sensitively response to, and quantifies the model through the empirical analysis.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.109-127
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• 2014

This study is devised out of the recognition that the existing standardization-related research has not sufficiently examined the overall social environment where a standard is actually made and diffused and the roles of the actors and the changes in them in the complex social system where multiple stakeholders exist. Against this backdrop, this study purports to reconstruct the dynamic process of developing and standardizing an innovative technology through a socio-technical approach involved by multiple stakeholders with different interests in the context of a socio-technical institutional environment. The specific goals to achieve the purpose include first, inspecting the characteristics of the interactions between the human actors and between the human and non-human actors in the socio-technical network surrounding a standardization process. Second, the study aimed to observe the activities of the focal actor who led the standardization process and its changing role. To that end, it analyzed the dynamic features of the process of standardizing a HD 3DTV broadcasting technology that took place in South Korea based on the actor network theory. As for the analysis method, the researchers personally took part in the actor network involving the new technology to analyze the dynamic characteristics of the network, applying the qualitative research method of survey and in-depth interviews and exploring the overall dynamics of environment, behavior and technology observed over the course of the entire standardization process.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.452-460
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• 2017

Rice fields are important stopover sites for the conservation of shorebirds during long-distance migration. These fields serve as food sources providing energy for the next leg of the journey. Shorebirds are able to change their preferred food source at stopover sites. However, the type and distribution of food resources remain unknown for the shorebirds in the Republic of Korea. Therefore, we studied the type and distribution pattern of food resource (macroinvertebrates, remaining rice, and other seeds) for shorebirds in the rice fields. We have identified potential and actual food sources for shorebirds in the rice fields. The potential food sources were collected by using a core-sampling method and the actual food source was ascertained by observational analysis. As a result, a total 19 species of benthic macroinvertebrates in 15 families were recorded as potential food sources. A total of 9 families in 9 orders of benthic macroinvertebrates known to be actual food sources were also recorded during the study period, including loaches, and a tuber of sea club rush. Also, the distribution of the food source depended on soil conditions generated by cultivation such as plowing, harrowing, and the use of pesticides. In the present study, we identified the type and distribution of food sources for shorebirds. This information can be used as essential primary baseline data for conservation of shorebirds using the rice fields of the Republic of Korea.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.487-496
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• 2009

This paper addresses an indexing scheme capable of efficiently processing range queries in a large-scale trajectory database. After discussing the drawbacks of previous indexing schemes, we propose a new scheme that divides the temporal dimension into multiple time intervals and then, by this interval, builds an index for the line segments. Additionally, a supplementary index is built for the line segments within each time interval. This scheme can make a dramatic improvement in the performance of insert and search operations using a main memory index, particularly for the time interval consisting of the segments taken by those objects which are currently moving or have just completed their movements, as contrast to the previous schemes that store the index totally on the disk. Each time interval index is built as follows: First, the extent of the spatial dimension is divided onto multiple spatial cells to which the line segments are assigned evenly. We use a 2D-tree to maintain information on those cells. Then, for each cell, an additional 3D $R^*$-tree is created on the spatio-temporal space (x, y, t). Such a multi-level indexing strategy can cure the shortcomings of the legacy schemes. Performance results obtained from intensive experiments show that our scheme enhances the performance of retrieve operations by 3$\sim$10 times, with much less storage space.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.3
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• pp.161-172
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• 2013

Metadata registry (MDR) is the international standard, developed by ISO/IEC for exchange and sharing data between databases. Many MDR systems are used in diverse domains such as medical service, bibliography, environment for sharing and integrating data. However, those systems have different physical structures individually because the MDR standard defines only the metamodel for registering and storing metadata. It causes heterogeneity between the system structures and requires additional cost to maintain interoperability. ISO/IEC 13249-8 Metadata Registry Access (MRA) is developing as an international standard to provide a consistent access facility to data stored in different metadata registries. However, MRA does not consider the relationships between the concepts (classes) defined in the MDR specification. It causes that incorrect query results returned from MDR systems. It also requires additional cost of modeling and rewriting queries to reflect each physical model. Therefore, this paper suggests eMRA which considers the relationships between the concepts in MDR. The comparative evaluations are described to show the advantages of eMRA. eMRA has superior performance in query modeling and referential integrity than MRA defined by the relationship between the concept of MDR.