• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.3
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• pp.411-427
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• 2010

Data sharing is an essential process for collaborative works particularly in the banking, finance and healthcare industries. These industries require many collaborative works with their internal and external parties such as branches, clients, and service providers. When data are shared among collaborators, security and privacy concerns becoming crucial issues and cannot be avoided. Privacy is an important issue that is frequently discussed during the development of collaborative systems. It is closely related with the security issues because each of them can affect the other. The tradeoff between privacy and security is an interesting topic that we are going to address in this paper. In view of the practical problems in the existing approaches, we propose a collaborative framework which can be used to facilitate concurrent operations, single point failure problem, and overcome constraints for two-party computation. Two secure computation protocols will be discussed to demonstrate our collaborative framework.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.184-201
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• 2013

In this paper, we study the problem of designing the power and number of cooperative node (CN) in the cooperation phase to maximize the average throughput for secondary user (SU), under the constraint of the total cooperation and transmission power. We first investigate the scheme of cooperative spectrum sensing without a separated control channel. Then, we prove that there indeed exist an optimal CN power when the number of CNs is fixed and an optimal CN number when CN power is fixed. The case without the constraints of the power and number of CN is also studied. Finally, numerical results demonstrate the characteristics and existences of optimal CN power and number. Meanwhile, Monte Carlo simulation results match to the theoretical results well.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.43-53
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• 2013

Lane marking detection based on a mono camera sensor provides a low cost solution to both ITS (intelligent transportation systems) and DAS (driver assistant systems). A number of methods and implementations have been reported in the literature. However, reliable detection is still an issue. Traditional approaches are mostly based on statistics or Hough transforms. However, the former approaches usually include many irrelevant detection areas, and the latter are not practical because actual lanes are not usually suitable for the approximation with linear or polynomial equations. In this paper, we focus on increasing the reliability of detection by reducing the detection of irrelevant areas while improving the detection of actual lane marking areas, which is usually a tradeoff for most conventional approaches. We use scale-space for that. Through experiments with real images obtained from various environments, we could achieve a significant improvement over traditional approaches.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.336-337
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• 2011

The popularity of general purpose GPU（GPGPU）makes the CPU-GPGPU heterogeneous architecture normal. Therefore, tradeoff the usage of CPU and GPGPU becomes a way to improve performance of programs. In this work, we exploit the properties of the CPU-GPGPU heterogeneous architecture and use them to accelerate the content based chunking operation of deduplication. We built a prototype system which is able to coordinate CPU and GPGPU to chunk file and has been proven to have a better performance compared to using either CPU or GPGPU alone.

• Journal of Korean Society for Quality Management
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• v.31 no.4
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• pp.239-246
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• 2003

Dynamic robust design has been regarded as the most powerful design methodology for improving product quality, Dynamic SN ratio adopted in dynamic robust design combines two major quality attributes, the variability around the linear function and the slope of the linear function, into a single design metric. The principal shortcoming associated with the dynamic SN ratio is that the metric is independent of designer's preferences for the quality attributes due to priori sets of attribute tradeoff values inherent in it. Therefore, a more rigorous preference­based design metric to accurately capture designer's intent and preference is needed. A new design metric that can be used in dynamic robust design is proposed. The effectiveness of the proposed design metric is examined with the aid of a demonstrative case study and the results are discussed.

• Journal of Advanced Navigation Technology
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• v.12 no.5
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• pp.429-436
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• 2008

In this paper, we study an optimization which determines the optimal sensing time and the number of cooperative sensing cognitive users for cooperative spectrum sensing scheme in cognitive radio networks. In cooperative spectrum sensing, cognitive users originally in inactive status are activated and take part in spectrum sensing along with transmitting cognitive users resulting in a reduced sensing time. Tradeoff between transmission rate gain and energy consumption due to cooperative sensing is formulated as a mixed integer programming problem which is solved for the optimal values.

• The Transactions of the Korea Information Processing Society
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• v.2 no.1
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• pp.106-118
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• 1995

In this work, the optimized design methodology in high-level synthesis related with scheduling and hardware allocation is developed by simulated annealing technique effectively modified . Applying this method to digital filter design, the optimized tradeoff problem of speed and hardware costs in pipelined digital filter case and array digital filter case are investigated. While, it is confirmed that the suggested method gives the improved cost function value faster and can be used in complicated digital filter design.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.2
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• pp.15-25
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• 2017

A System can be more Dependable from some types of Threats if the Dependability Level Against the Threat on the System is Increased. However, The Dependability-performance Tradeoff should be Considered because the Increased Dependability may Degrade the Performance of the System. Therefore, it is Efficient to Temporally Increase the Dependability Level to High only when an Threat is Predicted on the System in a Short time while Maintaining the Level in Low or mid in Normal Situations. In this Paper, we Present a Threat Prevention Strategy for a Networked Node by Dynamically Changing the Dependability Level According to the Threat Situation on its Logically/physically Neighboring Nodes. As case Studies, we Employ our Strategy to an Internet Server Against TCP SYN Flood Attacks and to a Checkpoint and Rollback System Against Transient Faults. Our Performance Analysis Shows that our Strategy can Effectively Relieve the Damage of the Failure without Serious Performance Degradation.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.32-49
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• 1996

An approach to providing computational support for concurrent design is discussed in the context of an automobile wiring harness design problem. Key issues include the development of an architecture that supports collaboration among specialists, the development of hierarchical representations that capture different characteristics of the design, and decomposition of tasks to achieve a tradeoff between efficiency and robustness of the system. We present an architecture in which the main design tasks are supported by agents-asynchronous and semi-autonomous modules that automate routine design tasks and provide specialized interfaces for working on particular aspects of the design. The agent communication and coordination mechanisms permit members of an engineering team to work concurrently, at different levels of detail and of different versions of the design. The design is represented hierarchically, with detailed models maintained by the participating agents. In conjunction with the architecture and design representations, issues pertaining to the exchange of information among different views of the design, management of dependencies and constraints, and propagation of design changes are discussed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.790-794
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• 2007

This paper presents a new index mapping method for DFT (Discrete Fourier Transform) and its application to multidimensional DFT. Unlike conventional index mapping methods such as DIT (Decimation in Time) or DIF (Decimation in Frequency) algorithms, the proposed method is based on two levels of decomposition and it can be very efficiently used for implementing multidimensional DFT as well as 1-dimensional DFT. The proposed pipelined architecture for multidimensional DFT is very flexible so that it can lead to the best tradeoff between performance and hardware requirements. Also, it can be easily extended to higher dimensional DFTs since the number of CEs (Computational Elements) and DCs (Delay Commutators) increase only linearly with the dimension. Various implementation options based on different radices and different pipelining depths will be presented.