• The Transactions of the Korea Information Processing Society
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• v.4 no.3
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• pp.709-719
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• 1997

Performance of an algorithm can be mesaurde from serval aspects.Suppose thre is a query formulation al-gorithm.Even though this algorithm shows high retrival performance, ie, high recall and percision, retriveing items can rake a long time.In this study, we time complexity of automatic query reformulation algorithms, named the query Tree, DNF method, and Dillon's method, and comparethem in theoretical and practical aspects using a tral-time performance)the absolute times for each algorithm to fromulate a query)in a Sun SparcStation 2. In experiments using three test sets, CSCM, CISI, and Medlars, the query Tree algorithm was the fastest among the three algorithms tested.

• ETRI Journal
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• v.37 no.3
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• pp.491-501
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• 2015

Spectrum sensing is an elementary function in cognitive radio designed to monitor the existence of a primary user (PU). To achieve a high rate of detection, most techniques rely on knowledge of prior spectrum patterns, with a trade-off between high computational complexity and long sensing time. On the other hand, blind techniques ignore pattern matching processes to reduce processing time, but their accuracy degrades greatly at low signal-to-noise ratios. To achieve both a high rate of detection and short sensing time, we propose fast spectrum sensing with coordinate system (FSC) - a novel technique that decomposes a spectrum with high complexity into a new coordinate system of salient features and that uses these features in its PU detection process. Not only is the space of a buffer that is used to store information about a PU reduced, but also the sensing process is fast. The performance of FSC is evaluated according to its accuracy and sensing time against six other well-known conventional techniques through a wireless microphone signal based on the IEEE 802.22 standard. FSC gives the best performance overall.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.5
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• pp.167-174
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• 2002

This paper analyzes the characteristics of three multipliers and squarers in finite fields GF(2/sup m/) from the point of view of processing time and area complexity. First, we analyze structures of three multipliers and squarers: 1) Systolic array structure, 2), LFSR structure, and 3) CA structure. To make performance analysis, each multiplier and squarer was modeled in VHDL and was synthesized for FPGA implementation. The simulation results show that CA structure is the best from the point view of processing time, and LFSR structure is the best from the point of view of area complexity.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.4
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• pp.160-168
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• 2011

A Frequency domain beamforming technique is widely used in sonar systems with a large number of beams and sensors. In the battlefield environment requiring real-time signal processing, it is needed to optimize the computational complexity of the spectrum computation to implement an efficient and fast frequency domain beamformer. So, in this paper, we proposed the pruned-GSFFT (pruned generalized sliding fast Fourier transform) as a new spectrum computation method. The proposed method help to reduce the computational complexity of the real-time partial spectrum computation by eliminating the redundancy between consecutive input samples and skipping the regardless frequency bands. Also the characteristics of the proposed pruned-GSFFT method and its computational complexity are compared to those of previous FFT algorithms.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.7
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• pp.299-303
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• 2005

This paper proposes an analytic method can estimate delay time considering crosstalk noise at an arbitrary node of RC-class interconnects under saturated ramp input using a simple closed-form expression. In the case of single interconnects, algebraic expression presented in existent research can estimate delay time under ramp input using delay time under step input, and we applied it to estimate delay time considering crosstalk noise. As the result, we can provide a intuitive analysis about signal integrity of circuits that include crosstalk noise reducing computational complexity significantly.

• Proceedings of the ESK Conference
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• 1995.10a
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• pp.62-74
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• 1995

This study surveys four characteristics (overall density, local density, grouping, complexity) to effect user's performance on the on-line terminal displays of commercial banks, and makes the new screen by the screen design procedure. The new screen includes to increase the number of groups and to arrange the items on the screen. And then, this study carrys out experiments to compare performance(operating time and error number ) by each screen. The result is described that the operating time decreases about 20% at the new OUT-screen than the existing OUT-screens; about 25% at the new IN-screen.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.868-874
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• 2007

A real-time frame-layer rate control algorithm with a token bucket traffic shaper is proposed for minimizing video duality variation. The proposed rate control method uses a non-iterative optimization method for low computational complexity, and performs bit allocation at the frame level to minimize variation in distortion between frames. In order to reduce the quality fluctuation, we use a sliding window scheme which does not require the pre-analysis process. Therefore, the proposed algorithm does not produce the delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better PSNR performance than the existing rate control method.

• Journal of Information Processing Systems
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• v.18 no.1
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• pp.97-114
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• 2022

Interest is increasing in electrocardiogram (ECG) signal analysis for embedded devices, creating the need to develop an algorithm suitable for a low-power, low-memory embedded device. Linear approximation of the ECG signal facilitates the detection of fiducial points by expressing the signal as a small number of vertices. However, dynamic programming, a global optimization method used for linear approximation, has the disadvantage of high complexity using memoization. In this paper, the calculation area and memory usage are improved using a linear approximated template. The proposed algorithm reduces the calculation area required for dynamic programming through local optimization around the vertices of the template. In addition, it minimizes the storage space required by expressing the time information using the error from the vertices of the template, which is more compact than the time difference between vertices. When the length of the signal is L, the number of vertices is N, and the margin tolerance is M, the spatial complexity improves from O(NL) to O(NM). In our experiment, the linear approximation processing time was 12.45 times faster, from 18.18 ms to 1.46 ms on average, for each beat. The quality distribution of the percentage root mean square difference confirms that the proposed algorithm is a stable approximation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2322-2327
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• 2009

Uncertainty of power system operation increases due to complexity and facilities diversification in the power system. Therefore the importance of SCADA(Supervisory Control and Data Acquisition) system which obtain and manage the actual data in real-time is very important. Accordingly in the studies of power system analysis, the efforts to include real-time power system analysis in simulation and applications are made in many ways. The real-time communication characteristics of SCADA system is considered so as to develop the power system analysis program that matches actual system conditions. The observation and management of SCADA system is realized by Intouch which is mainly used for factory automation and PSS/E(Power System Simulator for Engineers) provides real time system data. SQL DB and Python language is used for real-time communication between the softwares. It is very comfortable to use the various functions in Intouch WindowMaker.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3630-3656
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• 2018

Degree distribution can provide basic information for structural characteristics and internal relationship in social network. It is a critical procedure for social network topology analysis. In this paper, based on the mean-field theory, we study a special type of social network with exponential distribution of time intervals. First of all, in order to improve the accuracy of analysis, we propose a spreading coefficient algorithm based on intimate relationship, which determines the number of the joined members through the intimacy among members. Then, simulation show that the degree distribution of follows the power-law distribution and has small-world characteristics. Finally, we compare the performance of our algorithm with the existing algorithms, and find that our algorithm improves the accuracy of degree distribution as well as reducing the time complexity significantly, which can complete 29.04% higher precision and 40.94% lower implementation time.