• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.9
• /
• pp.1028-1036
• /
• 2008

In the OFDM system, IQ imbalance problem happens at the RF front-end of transceiver, which degrades the BER(bit error rate) performance because it affects the constellation in the received signal. Also, phase noise is generated in the local oscillator of transceivers and it destroys the orthogonality between the subcarriers. Conventional PNS algorithm is effective for phase noise suppression, but it is not useful anymore when there are jointly IQ(In-phase and Quadrature) imbalance and phase noise. Therefore, in this paper, we analyze the effect of IQ imbalance and phase noise generated in the down-conversion of the receiver. Then, we estimate and compensate the IQ imbalance and phase noise at the same time. Compared with the conventional method that IQ imbalance after IFFT is estimated and compensated in front of FFT via the feedback, this proposed method extracts and compensates effect of IQ imbalance after FFT stage. In case IQ imbalance and phase noise exist at the same time, we can decrease complexity because it is needless to use elimination of IQ imbalance in time domain and training sequences and preambles. Also, this method shows that it reduces the ICI and CPE component using adaptive forgetting factor of MMSE after FFT.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.8
• /
• pp.1503-1517
• /
• 1994

Intelligent Motion Planning System(IMPS) is presented for a robot to achieve an efficient path toward the given target point in two dimensional unknown environment is constructed with unrestricted obstacle shapes. IMPS consists of three components for making intelligent motion. These components are real-time motion planning algorithm based on a discontinous boundary method, fuzzy neural network decision system for heuristic knowledge representation, and world modeling with forgetting and reinforcing memory cells. First of all, in real-time motion planning algorithm, the behavior-based architectural method is used to generate subgoal. A behavior generates a subgoal independently by using the method of discontinuous boundary in sensed area. The discontinuous boundary method is a new proposed fast obstacle avoidance algorithm. The second component is fuzzy neural network decision system for accomplishing the subgoal. The heuristic rules are imbedded on the fuzzy neural network to make an intelligent decision. The last one is a forgetting, reinforcing memory technique for the construction of external world map. The activation values of all activated memory cells in grid space are decreased monotonically and after all they are burned out. Therefore, after sufficient journey, robot can have a stationary world map even if the dynaic obstacles exist. Using the IMPS, several simulations show the efficient achievement of target point in unknown enviroment with obstcles of various shapes.

• The Korean Journal of Archival Studies
• /
• no.43
• /
• pp.43-70
• /
• 2015

The value and validity of elite oral materials have been questioned because of their gaps with 'fact'. The purpose of this article is to analyze these gaps and to propose some solutions that can reduce the gaps. According to the analysis of this article, there are three types of the gaps that qualitatively differ from each other. The first type of the gaps is produced in the process of generation of memory. This type is made because informants cognize and memorize the facts that exist outside themselves. Selective cognition, selective memory and individual experience come under this category. The second type is produced in the process of preserving the memory. Forgetting and memory transformation are main examples of this type. The third type is produced in the process of the interviews with the informants. False statements or lies fall into this category. The main conclusions are as follows. 1) all gaps in oral materials are not necessarily negative. It is because Some of these gaps- the first and the second type- are not only parts of the real world but also very useful for interpreting the world. 2) The third type of the gaps are very harmful and it is need to be eradicated or reduced. For this, this article proposes some solutions.

• Journal of the Korean Society of Costume
• /
• v.62 no.2
• /
• pp.68-77
• /
• 2012

Hair style takes a large part in emphasizing to the appearance and the effect of image transformation with fashion to the modern people whose competition is appearance in 21 century. According to the development of mass media and the exchange of the life style. Image creation which correspond to T.P.O is needed and style-up is also required in modern costume, as the coordination for special day is routinized. In this study, the expression of a fine and organic line shown as a motive in Art Nouveau style's works is applied to style-up design and a new view sight to the style-up design through the art history is suggested with developing style-up design to satisfy the upgraded customer's requirements. The feminine beauty is appeared as a various image by applying style-up design from Art Nouveau style through this study. and the infinite possibility to the design development can be found with activated motive of Art Nouveau. These Art Nouveau trend will be a foundation to the inspiration of high artistic design and will be helpful to the aesthetic satisfaction of the elegance modern people. Therefore, I hope this study will be a fundamental data for creative development of hair design through the art history which may be forgetting.

• Proceedings of the KIEE Conference
• /
• 2007.04c
• /
• pp.29-33
• /
• 2007

In this paper, time-varying parameter of passive telemetry RF sensor system is estimated using RLS(Rescursive $\leq$* Square) algorithm. In order to overcome the problems such as power limits and complication that general RF sensor system including IC chip has, the principle of inductive coupling is applied to model sensor system The model parameter is rearranged for applying RLS algorithm based on mathematical model to the derived model using inductive coupling principle. Time variant parameter of rearranged model is estimated using forgetting factor, and in case measured data is contaminated by noise and modelling error, the performance of RLS algorithm characterized by the convergence of squared error sum is verified by simulation.

• Journal of Oriental Neuropsychiatry
• /
• v.24 no.3
• /
• pp.245-250
• /
• 2013

Objectives : Psychasthenia is a psychological disorder that is characterized by phobias, obsessions, compulsions, or excessive anxiety. Their thoughts can be scattered and require significant effort to organize, often resulting in sentences that do not come out as intended, making little sense to others. Methods : Two Patients with psychasthenia are unable to resist specific actions or thoughts, regardless of their maladaptive nature and have insufficient control over their conscious thinking and memory, sometimes wandering aimlessly and/or forgetting what they were doing. Results : The constant mental effort induces physiological fatigue, which worsens the condition. Nevertheless, psychasthenia has become a forgotten disorder. We observed two cases that are worthy of the original definition of psychasthenia. Conclusions : It can be concluded that patients with psychasthenia complain of sinking because of a reduction in psychological tension or an effort to recover the reduction in tension.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1352-1355
• /
• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surface. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamometer. Based on the parameter estimation of cutting dynamics and the admittance model-based nanodynamic control scheme, simulation results are shown.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.12C
• /
• pp.1280-1287
• /
• 2006

We propose a modified stochastic gradient-based (MSGB) filter showing that the filter is the solution to an optimization problem. This paper analyzes the properties of the MSGB filter that corresponds to the nonlinear adaptive filter with additional update terms, parameterized by the variable scaling factor. The variably parameterized MSGB filter plays a role iii connecting the fixed parameterized MSGB filter and the null parameterized MSGB filter through variably scaling parameter. The stability regions and misadjustments are shown. A system identification is utilized to perform the computer simulation and demonstrate the improved performance feature of the MSGB filter.

• Proceedings of the KIEE Conference
• /
• 2001.05a
• /
• pp.210-213
• /
• 2001

This study presents an effective variable forgetting factor method based on fuzzy logic to suppress frequency droop in extended integral load frequency control. The performance of the extended integral control is greatly dependent on the decaying factor. For an optimal or near optimal performance, it is necessary that the decaying factor as well as the feedback gains should be changed very quickly in response to changes in the system dynamics. However, because of its time-varing characteristic, the optimal decaying factor is difficult to be selected analytically. By adopting fuzzy set theory, the decaying factor can be determined quickly to respond to the variation of the feedback signals. This study builds a fuzzy rule base with use of the change of frequency and its rate as inputs. The computer simulation has been conducted for the single machine system. The simulation results show that the proposed fuzzy 1o81c based controller yields more improved control performance than the conventional PI controller.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.39 no.4
• /
• pp.414-422
• /
• 2002

In this paper, we propose a new method of adaptive neuro-fuzzy control using CFCM(Conditional Fuzzy c-means) clustering and fuzzy equalization method to deal with adaptive control problem. First, in the off-line design, CFCM clustering performs structure identification of adaptive neuro-fuzzy control with the homogeneous properties of the given input and output data. The parameter identification are established by hybrid learning using back-propagation algorithm and RLSE(Recursive Least Square Estimate). In the on-line design, the premise and consequent parameters are tuned to RLSE with forgetting factor due to a characteristic of time variant. Finally, we applied the proposed method to the water temperature control system and obtained better results than previous works such as fuzzy control.