• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.421-429
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• 2006

Recently, DHT-based Structured P2P System have a attention to scalability and providing efficient lookup by routing. Retrieving content of DHT-based P2P require knowledge of the exact identifier of sharing file. But user may wish to search for sharing file using descriptive keyword or content. To resolve the problem, this paper propose Extended-CAN mechanism to support keyword search. We defined content-based keyword and identifier of sharing file, and PLS extended to KID and CKD for keyword, common keyword processing. As a result, Extended-CAN mechanism provide efficient keyword search for DHT-based Structured P2P System.

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.465-472
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• 2007

With the recent proliferation of the use of semi-structured data such as XML, it becomes more important to efficiently store and manage the semi-structured data. The XML data can be logically modelled as a rooted tree e.g., the DOM tree. In order to process a query on the XML data, we traverse the tree structure. In this paper we present an algorithm that places the XML data to disk blocks. The proposed algorithm assigns a number to each node of the tree in a bottom-up fashion. Then, the nodes are allocated to disk blocks using the assigned number. The proposed algorithm does not need access pattern information, and provides good performance for any access pattern. The characteristics of the proposed method are presented with analysis. Through experiments, we evaluate the performance of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.859-867
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• 2010

In this paper, we propose some parallel structures of the word-based nonlinear combining functions in word-based stream cipher, high-speed versions of general (bit-based) nonlinear combining functions. Especially, we propose the high-speed structures of popular four kinds in word-based nonlinear combiners using by PS-WFSR (Parallel-Shifting or Parallel-Structured Word-based FSR): m-parallel word-based nonlinear combiner without memory, m-parallel word-based nonlinear combiner with memories, m-parallel word-based nonlinear filter function, and m-parallel word-based clock-controlled function. In addition, we propose an implementation example of the m-parallel word-based DRAGON stream cipher, and determine its cryptographic security and performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2691-2697
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• 2010

Shader instructions and Compiler are designed for supporting 3D graphic shader 3.0 API. Variable-length instructions are proposed to reduce the size of hardware of graphic processor in SIMD structure by shortening the length of instructions. The designed shader compiler supports variable and two phased structured instructions, and can be programmable at ESSL level. Conformance Test proposed by Khronos group is accomplished to verify the design result of instructions and complier. The test result shows overall average 37% performance improvement at the 16 functions of basic GL shader.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.469-476
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• 2016

Relational Database Management Systems have become de facto database model among most developers and users since the inception of Data Science. From IoT devices, sensors, social media and other sources, data is generated in structured, semi-structured and unstructured formats, in huge volumes, thereby the difficulty of data management greatly increases. Organizations that collect large amounts of data are increasingly turning to non relational databases - NoSQL databases. In this paper, through experiments with real field data, we demonstrate that MongoDB, a document-based NoSQL database, is a better alternative for building a Telco Subscriber Data Management System which hitherto is mainly built with Relational Database Management Systems. We compare the existing system in various phases of data flow with our proposed system powered by MongoDB. We show how various workloads at some phases of the existing system were either completely removed or significantly simplified on the new system. Based on experiment results, using MongoDB for managing telco subscriber data turned out to offer performance better than the existing system built with MSSQL Server.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.189-201
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• 2011

In this paper, we design an ontology which provides interoperability by integrating typical metadata specifications and defines concepts and semantic relations between concepts that are used to describe metadata for learning objects in university courses. And we organize a hierarchical structured e-Learning system for efficient retrieval of learning objects on many local storages that use different specifications to describe metadata and propose a query processing method based on inferences. The proposed e-Learning system can provide more accurate and satisfactory retrieval service by using the designed ontology because both learning objects that be directly connected to user queries and deduced learning objects that be semantically connected to them are retrieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.821-828
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• 2008

In this paper, we present an optimized design of RS(23,17) decoder for UWB, which uses the pipeline structured-modified Euclidean(PS-ME) algorithm. Firstly, the modified processing element(PE) block is presented in order to get rid of degree comparison circuits, registers and MUX at the final PE stage. Also, a degree computationless decoding algorithm is proposed, so that the hardware complexity of the decoder can be reduced and high-speed decoder can be implemented. Additionally, we optimize Chien search algorithm, Forney algorithm, and FIFO size for UWB specification. Using Verilog HDL, the proposed decoder is implemented and synthesized with Samsung 65nm library. From synthesis results, it can operate at clock frequency of 250MHz, and gate count is 17,628.

• Journal of the Korea Society of Computer and Information
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• v.6 no.3
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• pp.23-28
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• 2001

There has been several meaning full efforts to save costs on system development and expand the life-time of a system in changeful IT circumstance. It was a module-based architecture that empower productivity at structured programming era. But it couldn't grow nor evolve, but could raise only calling frequency of module. But OOP or OO-method overcome limit of structured programing by class inheritance and/or overloading and/or over-riding. A component centric architecture, what is mixture of distributed systems, like CORBA or DCOM with OOP, can support not only high reusability or expansion of life-time but also Plug-&-Play between them. To assemble these component to build a new system in easy way, the well-formed specification of a component is highly required. At this study, the enhanced referential component architecture and its UML specification will be suggested.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.578-581
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• 2014

Blackhole attack, a kinds of attacks to routing function, can cause critical effects to network transmission function, Especially, on MANET(Mobile Ad-hoc Network) which it is not easy to prepare functions to respond malicious intrusion, transmission functions of entire networks could be degraded. In this paper, effects of blackhole attack to network transmission performance is analyzed on lattice structured MANET. Specially, performance is measured for various location of blackhole attack on lattice MANET, and compared with the performance of random structured MANET. This paper is done with computer simulation, VoIP(Voice over Internet Protocol) traffic is used in simulation. The results of this paper can be used for data to deal with blackhole attack.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4706-4724
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• 2020

With various structured data, such as the company size, loan balance, and savings accounts, the voice of customer (VOC), which is text data containing contact history and counseling details was analyzed in this study. To analyze unstructured data, the term frequency-inverse document frequency (TF-IDF) analysis, semantic network analysis, sentiment analysis, and a convolutional neural network (CNN) were implemented. A performance comparison of the models revealed that the predictive model using the CNN provided the best performance with regard to predictive power, followed by the model using the TF-IDF, and then the model using semantic network analysis. In particular, a character-level CNN and a word-level CNN were developed separately, and the character-level CNN exhibited better performance, according to an analysis for the Korean language. Moreover, a systematic selection model for optimal text mining techniques was proposed, suggesting which analytical technique is appropriate for analyzing text data depending on the context. This study also provides evidence that the results of previous studies, indicating that individual customers leave when their loyalty and switching cost are low, are also applicable to corporate customers and suggests that VOC data indicating customers' needs are very effective for predicting their behavior.