• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1575-1581
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• 2003

As a society has progressed rapidly toward a highly advanced digital information age, a multimedia communication service for acquisition, transmission and storage of image data as well as voice has being commercialized externally and internally. However, in the process of digitalization or transmission of data, noise is generated by several causes, and researches for eliminating those noises have been continued until now. There were the existing FFT(fast fourier transform) and STFT(short time fourier transform) for removing noise but it's impossible to know information about time and time-frequency localization capabilities has conflictive relationship. Therefore, for overcoming these limits, wavelet transform which is presented as a new technique of signal processing field is being applied in many fields recently. Because it has time-frequency localization capabilities it's Possible for multiresolution analysis as well as easy to analyze various signal. And when two wavelet base were designed to form Hilbert transform pair, wavelet pair provide superior performance than the existing DWT(discrete wavelet transform) in data characteristic detection. Therefore in this parer, we removed impulse noise by using adaptive-length median filter and two dyadic wavelet base which is designed by truncated coefficient vector.

• Journal of KIISE:Software and Applications
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• v.33 no.11
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• pp.915-922
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• 2006

Recently, the requirements of the embedded software are getting diverse as the diversity of embedded software application fields increases. The systematic development methods are issued to deal with the dependency between hardware and software. However, the existing development methods have not considered the software's close connection to hardware and the high-level reusability for common requirements of several similar domains. In this paper, we propose a design method of development process model of product lines to support an efficient development method for embedded software. For this, we firstly suggest a domain scoping method and an IDEF0(Integration DEFinition)-based business model for extracting the efficient requirements. Next, we present a component deriving method based on the service architecture and an architecture design method after considering the hardware dependency. And we explain the artifacts of MSDFS(Multi Sensor Data Fusion System) at each design step in order to show how the proposed model can be applied to the embedded software development.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3B
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• pp.209-216
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• 2003

In this paper, we propose ATM switch structure including AAL type 2 switch which can efficiently transmit low-bit rate data, even if the network has many endpoints. We simulate the architecture of ATM switch fabric that is modeled in computer program and analyze the performance according to offered loads. ATM switch proposed in this paper can support cell switching for all types of AAL cells which consist of AAL type 1, AAL type 2, AAL type 3/4, and AAL type 5 cells. We propose two switch fabric methods; One supports the AAL type 2 cell processing per input port, the other global AAL type 2 cell processing for every input port. The simulation results show that the latter is superior to the former. But the former has a merit for easy implementation and extensibility. The proposed ATM switch fabric is widely applicable to mobile communication, narrow band services over ATM network and wireless ATM as well as general ATM switching fabric.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.2
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• pp.178-188
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• 2016

The traffic in the wired and wireless networks has increased exponentially because of increase of smart phone and improvement of PC performance. Multimedia services and file transmission such as Facebook, Youtube occupy a large part of the traffic. CDN is a technique that duplicates the contents on a remote web server of content provider to local CDN servers near clients and chooses the optimal CDN server for providing the content to the client in the event of a content request. In this paper, the content request message between CDN servers and the client used the SCRP algorithm utilizing the MST algorithm and the traffic throughput was optimized. The average response time for the content request is reduced by employing HC_LRU cache algorithm that improves the cache hit ratio. The proposed SCRP and HC_LRU algorithm may build a scalable content delivery network system that efficiently utilizes network resources, achieves traffic localization and prevents bottlenecks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1085-1092
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• 2012

Mobile communication systems define user state transition mechanisms in order to manage radio resources and battery power efficiently. In the state transition mechanism, a state with a higher energy consumption inherently offers a shorter access delay, so there is a tradeoff between the energy and delay performances. In this paper, we analyze the user state transition mechanism of UMTS by considering the bursty traffic attributes of mobile applications. We perform a numerical evaluation for both the energy consumption and the activation delay by Markov modeling of the state transition mechanism, and investigate their tradeoff relationship as functions of operational parameters. The resulting energy-delay tradeoff curves clearly show an achievable performance bound of the user state transition mechanism and also offer an optimal operation strategy to minimize the energy consumption while guaranteeing the delay requirement.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.183-188
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• 2009

Wireless sensor networks will be broadly deployed in the real world and widely utilized for various applications. A prerequisite for secure communication among the sensor nodes is that the nodes should share a session key to bootstrap their trust relationship. The open problems are how to verify the identity of communicating nodes and how to minimize any information about the keys disclosed to the other side during key agreement. At any rate, any one of the existing schemes cannot perfectly solve these problems due to some drawbacks. Accordingly, we propose a new pre-distribution scheme with the following merits. First, it supports authentication services. Second, each node can only find some indices of key spaces that are shared with the other side, without revealing unshared key information. Lastly, it substantially improves resilience of network against node capture. Performance and security analyses have proven that our scheme is suitable for sensor networks in terms of performance and security aspects.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.311-318
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• 2013

Recently, there have been many studies on RFID-based SCM. Yet, studies of synchronizing errors caused by tracking logistics information in supply chain, and activating & monitoring RFID infra is still insufficient. Also, there is no case of developing the intelligent SCM system enabling total monitoring and controlling RFID Infra by applying these technologies. Logistics information synchronization based Smart SCM model is intelligent supply chain service model to monitor the status of the RFID equipments in supply chain and the synchronization of the logistics process in each logistics point through one integrated view, as well as to react instantly by providing the information to help the various decision makings, when the emergency occurs. By adopting global logistics standard, RFID related standard specification, EPCIS standard, and SSI middleware platform, this model provides the domestic standard specification.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.9
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• pp.197-206
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• 2020

Collaborative research in science applications based on HPC service needs rapid transfers of massive data between research colleagues over wide area network. With regard to this requirement, researches on enhancing data transfer performance between major superfacilities in the U.S. have been conducted recently. In this paper, we deploy multiple data transfer nodes(DTNs) over high-speed science networks in order to move rapidly large amounts of data in the parallel filesystem of KISTI's Nurion supercomputer, and perform transfer experiments between endpoints with approximately 130ms round trip time. We have shown the results of transfer throughput in different size file sets and compared them. In addition, it has been confirmed that the DTN cluster with three nodes can provide about 1.8 and 2.7 times higher transfer throughput than a single node in two types of concurrency and parallelism settings.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.1961-1974
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• 1997

WWW has accepted widely to the who wants the hypermedia-based internet services. And WWW introduces intranet environment which consists of the networks supporting TCP/IP and HTTP protocol for processing the task of company inside that. Intranet application should support not only acquiring the informations, but also producing, modifying and deleting the ones. But since previous hypermedia development methods lack modeling behavior of system and reuse, we need a new method for intranet application. In this thesis, we have proposed the OOIDM(Object Oriented Intranet application Development Method)supporting modeling behavior of system and reuse. And we have proposed the design patterns available for the intranet domain in order to reuse the design information. And we introduces a case study about OOIDM applying design patterns. Adaptation of design patterns to intranet domain gives us much benefits. Design patterns make it easier to reuse the successful design, architecture and reducing the design decisions.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.1907-1920
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• 1997

In this paper, we present integrated model of postal business that would be newly organized. The integrated model is developed through four phase. First, postal business is analyzed by three parts;collection, transportation and delivery. Second, the modeling criteria are developed that will be used for designing integrated postal business model. Third, object-oriented concepts are used by the steps of postal business modeling criteria captured. Finally, methods applied to developed model are grouped according to their function. Also, active-based mechanisms such as trigger and constraints are developed, and knowledge-based mechanisms such as inference are developed. These selected methods and attributes are encapsulated into objects. These constitute an object-active-knowledge based database model. Finally, Operational Scenario and Service Scenario are composed for real application according to proposed O-A-K model.