• Journal of KIISE:Computer Systems and Theory
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• v.33 no.11
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• pp.820-829
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• 2006

Wireless sensor networks consisting of hundreds to thousands of nodes are expected to be increasingly deployed in coming years, as they enable reliable monitoring and analysis of physical worlds. These networks have unique features that are very different from traditional networks, e.g., the numerous numbers of nodes, limitation in power, processing, and memory. Due to these unique features of wireless sensor networks, sensor data management including querying becomes a challenging problem. Furthermore, due to wide popularization of the Internet and its facility in use, it is generally accepted that an unattended network can be efficiently managed and monitored over the Internet. In particular, in order to more efficiently query and manage data in a sensor network. in this paper, the architecture of a sensor gateway including web-based query server is presented and its implementation detail is illustrated. The presented web-based gateway is largely divided into two important parts: Internet part and sensor network part. The sensor network part plays an important role of handling a variety of sensor networks, including flat or hierarchical network architecture, by using internally layered architecture for efficiently querying and managing data in a sensor network. In addition, the Internet part provides a modular gateway function for favorable exchange between the sensor network and Internet.

• Smart Media Journal
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• v.9 no.2
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• pp.51-62
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• 2020

Starting with the "Smart Grid National Road Map" in 2010, the Smart Grid 2030 was introduced through the basic plan and implementation plan of the intelligent power grid with the goal of building the world's first national smart grid. In this paper, we intend to build a power domain ontology based on the power business platform based on the upper and lower conceptual models of the "Smart Grid Interoperability Standard Framework and Roadmap", the standard of implementation plan. Ontology is suitable for expressing and utilizing the smart grid conceptual model because it considers hierarchical structure as knowledge defines the properties of entities and relationships between entities, but there is no research related to them. Therefore, in this paper, the upper ontology was defined as a major category for smart grid-related fields, and the lower ontology was defined as detailed systems and functions for the upper ontology to construct the ontology. In addition, scenarios in various situations that could occur in the power system were constructed and significant inference results were derived through inference engines and queries.

• Journal of KIISE:Software and Applications
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• v.28 no.9
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• pp.688-698
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• 2001

A homonym could be disambiguated by anther words in the context such as nouns, predicates used with the homonym. This paper proposes a homonym disambiguation system based on statistical semantic information which is extracted from definitions in dictionary. The semantic information consists of nouns and predicates that are used with the homonym in definitions. In order to extract accurate semantic information, definitions are used with the homonym in definitions. In order to extract accurate semantic information, definitions are classified into two types. One has hyponym-hypernym relation between title word and head word (homonym) in definition. The hyponym-hypernym relation is one level semantic hierarchy and can be extended to deeper levels in order to overcome the problem of data sparseness. The other is the case that the homonym is used in the middle of definition. The system considers nouns and predicates simultaneously to disambiguate the homonym. Nine homonyms are examined in order to determine the weight of nouns and predicates which affect accrutacy of homonym disambiguation. From experiments using training corpus(definitions in dictionary), the average accruracy of homonym disamguation is 96.11% when the weight is 0.9 and 0.1 for noun and verb respectively. And another experiment to meaure the generality of the homonym disambiguation system results in the 80.73% average accuracy to 1,796 untraining sentences from Korean Information Base I and ETRI corpus.

• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.125-134
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• 2008

We implemented a system being able to suggest example sentences for multiple choice tests, considering the level of students. To build the system, we designed an automatic method for sentence generation, which made it possible to control the difficulty degree of questions. For the proper evaluation in the multiple choice tests, proper size of question pools is required. To satisfy this requirement, a system which can generate various and numerous questions and their example sentences in a fast way should be used. In this paper, we designed an automatic generation method using a linguistic resource called WordNet. For the automatic generation, firstly, we extracted keywords from the existing sentences with the morphological analysis and candidate terms with similar meaning to the keywords in Korean WordNet space are suggested. When suggesting candidate terms, we transformed the existing Korean WordNet scheme into a new scheme to construct the concept similarity matrix. The similarity degree between concepts can be ranged from 0, representing synonyms relationships, to 9, representing non-connected relationships. By using the degree, we can control the difficulty degree of newly generated questions. We used two methods for evaluating semantic similarity between two concepts. The first one is considering only the distance between two concepts and the second one additionally considers positions of two concepts in the Korean Wordnet space. With these methods, we can build a system which can help the instructors generate new questions and their example sentences with various contents and difficulty degree from existing sentences more easily.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.77-82
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• 2018

Recently, as cloud services become popular with general users, users' information is freely transmitted and received among the information used in the cloud environment, so security problems related to user information disclosure are occurring. we propose a method to secure personal information of multiple users by making personal information stored in the cloud server and a key for accessing the shared information so that the privacy information of the multi users using the cloud service can be prevented in advance do. The first key used in the proposed scheme is a key for accessing the user 's personal information, and is used to operate the information related to the personal information in the form of a multi - layer. The second key is the key to accessing information that is open to other users than to personal information, and is necessary to associate with other users of the cloud. The proposed scheme is constructed to anonymize personal information with multiple hash chains to process multiple kinds of information used in the cloud environment. As a result of the performance evaluation, the proposed method works by allowing third parties to safely access and process the personal information of multiple users processed by the multi - type structure, resulting in a reduction of the personal information management cost by 13.4%. The efficiency of the proposed method is 19.5% higher than that of the existing method.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.763-771
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• 2010

The rapid increase of wildlife passage installation since the late 2000s was aimed to reduce roadkill caused by habitat fragmentation and losses related to road construction, but wildlife-vehicle collisions are now still occurred even near the wildlife passage area. This is the reason that the effectiveness of wildlife passage have not been evaluated in combination with absence of monitoring data and management strategy of the wildlife passage. The AHP method are used, in this study, to identify the evaluation factors affecting the effectiveness of the present 367 wildlife passages in a mitigation measures to reduce road effects on wildlife species. Ten evaluation factors are derived from third levels in the AHP analysis. Priority setting to identify appropriate management strategies in first level is selected among four second levels on facility, environment, wildlife species and management tool. The AHP analysis suggested that neighboring environments are the most important factor at the second level, and passage structure, harmony with natural surroundings, wildlife occurrence and monitoring of the passage are also important factors at the third levels. In summary, effective measurements of wildlife passage management is based on managing the passage with neighboring topography and natural surrounding. This is useful to establish wildlife passage management strategy in order to reduce the negative effects of roads on wildlife species.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.543-551
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• 2014

This study has searched to find a program in order to manage simply and practically use the expelled AtoN database from the AtoN Simulator and to support the idea decision for the AtoN placement. It examines a program that manages AtoN database through the hierarchy structure, history card and endowment with condition same as a scenario. And accomplishes this study's goal owing to realizing AtoN operational software that helps for visual, hearing sense, fixed amount verification upon AtoN placement project. The AtoN operational software contributes not only flexible control like a newly establishment, relocation etc, but also supports idea decision for AtoN placement plan through many functions such as condition search, virtual sailing and fixed amount appraisal result exhibition, etc. Through utilization of this, it is to help upon the presupposition of the impact to ship or sailor about many designs and in addition, upon the judgment of whether or not for the efficiency and appropriation of the design. It is expected to reduce possible failure costs and management costs due to AtoN design and placement plans, because to compare more various designs thru the easier verification method.

• Journal of Korea Water Resources Association
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• v.51 no.9
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• pp.769-782
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• 2018

Estimation of design floods is typically required for hydrologic design purpose. Design floods are routinely estimated for water resources planning, safety and risk of the existing water-related structures. However, the hydrologic data, especially streamflow data for the design purposes in South Korea are still very limited, and additionally the length of streamflow data is relatively short compared to the rainfall data. Therefore, this study collected a large number design flood data and watershed characteristics (e.g. area, slope and altitude) from the national river database. We further explored to formulate a scaling approach for the estimation of design flood, which is a function of the watershed characteristics. Then, this study adopted a Hierarchical Bayesian model for evaluating both parameters and their uncertainties in the regionalization approach, which models the hydrologic response of ungauged basins using regression relationships between watershed structure and model. The proposed modeling framework was validated through ungauged watersheds. The proposed approach have better performance in terms of correlation coefficient than the existing approach which is solely based on area as a predictor. Moreover, the proposed approach can provide uncertainty associated with the model parameters to better characterize design floods at ungauged watersheds.

• Journal of Cadastre & Land InformatiX
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• v.50 no.1
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• pp.47-62
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• 2020

As demands and applications of spatial information increase, different aspects of quality management have been raised as an important issue. This study suggests a quality management method for consumer-oriented spatial information, providing the consumer satisfaction. As opposed to the demands mentioned, less attention has been paid on the quality for the spatial information. So far, most of spatial information producers have kept their own independent quality management system and standard. Because of this unconscious response, it has been difficult to reflect the consumer's various and flexible demands from the silo structure of the quality management systems and regulations. The explosive increase of spatial information products creates quality-related problems such as limited time and budget for the consumer-oriented quality management. To solve these problems this study suggests to use a minimum number of the basic spatial information products which can guarantee better qualities when other products are combined. Because each of the spatial information product can include several other sub-products inside, it can have intrinsic characteristics such as geographic accuracy relationships between the products when combined and a hierarchical structure in each product in terms of the quality management mentioned. To prove the usability of the model, a case of the National Spatial Data Infrastructure Center is used because the Center collects and distributes an enormous amount of spatial information to the public and private sector.

• The Transactions of the Korea Information Processing Society
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• v.7 no.10
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• pp.3182-3194
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• 2000

It is strongly beliefed that Video on Demand(VOD) will become one of the most promising services in Broadband Integrated Services Digital Network(B-ISDN) for the nest generation VOD service can be classified into two types of services 'Near VOD(NVOD) and Interactive VOD(IVOD). For both services, some video servers should be installed at some nodes(especially, at the root node for NVOD service) in the tree structued VOD network,so that each node with video server stores video programs and distribules stored programs to customers. We consider thre kinds of cost.a program transmission cost, a program storage cost, and a video server installation cost. There exists a trade-off relationship among those three costs according to locationsl of video servers and the kinds of programs stord at each video server. Given a tree structured VOD network, and the total number of programs being served in the network, the resource allocation problem in a VOD network providing both IVOD and NVOD services is to determine where to install video servers for IVOD service, which and how many programs should be stored at each video server for both IVOD and NVOD services, so as to minunize the total cost which is the sum of three costs for both IVOD and NVOD services. In this paper we develop an efficient cynamic programming algorithm for solving the problem. We also implement the algorithm based on a service policy assumed in this paper.