• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.3
• /
• pp.277-283
• /
• 2006

A recently proposed method for stabilizing haptic interfaces and teleoperation systems was tested with a 'PHANToM' commercial haptic device. The 'Passivity Observer' (PO) and 'Passivity Control1er' (PC) stabilization method was applied to stabilize the system but also excited a high frequency mode in the device. To solve this problem, we propose a method to use a timevarying desired energy threshold instead of fixed zero energy threshold for the PO, and make the actual energy input follow the timevarying energy threshold. With the time-varying energy threshold, we make the PC control action smooth without sudden impulsive behavior by distributing the dissipation. The proposed new PO/PC approach is applied to PHANToM with high stiffness (K = 5000N/m), and stable and smooth contact is guaranteed. Resetting and active environment display problems also can be solved with the reference energy following idea.

• The Journal of Information Technology
• /
• v.6 no.3
• /
• pp.115-135
• /
• 2003

Customers expect to make a long-term relationship with customers more efficiently, marketing developed gradually. With the help of Internet of Telecommunication, communication with customers and the frequency and speed of the problem solving has improved greatly. Recently customers expect more and more personal contact with companies. CRM system called personal marketing and personalization can be a powerful tool for customer acquisition and support. This paper studied a brief introduction to the CRM system and go into the problems that should be considered which phase to emphasize what Enterprise Establishment evolvement.

• Journal of Electrical Engineering and Technology
• /
• v.4 no.2
• /
• pp.277-281
• /
• 2009

The complex resonant frequency problem of a superconductor patch is formulated in terms of an integral equation which is the kernel of a dyadic Green's function. To include the effect of the superconductivity of the microstrip patch, the surface complex impedance of the superconductor film is introduced using the two fluids model of Gorter and Casimir. The Galerkin procedure is used in the resolution of the electric field integral equation. Numerical results concerning the effect of the operating temperature of a superconductor patch on the characteristics of the antenna are presented.

• Journal of the Korea Computer Industry Society
• /
• v.4 no.10
• /
• pp.587-598
• /
• 2003

This paper construct two-level word similarity relation matrices about title and to scientific treatise. As guide keyword similarity relation matrices which is constructed to co-occurrence frequency base same time keeps recall rater by query expansion by tolerance relation, it is index structure to improve the precision rate by two-level contents base retrieval. Therefore, draw area knowledge through subject analysis and reasoned user's information request and area knowledge to fuzzy logic base. This research is research to improve vocabulary mismatch problem and information expression having essentially on query.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.8
• /
• pp.878-882
• /
• 2010

DaaS model that surrogates their data has a problem of privacy leakage by service provider. In this paper, we analyze inference attack that can occur on encrypted data that consist of multiple column through index, and we suggest b-anonymity to protect data against inference attack. We use R+-tree technique to minimize false-positive that can happen when we use an index for efficiency of data processing.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.5 no.4
• /
• pp.38-48
• /
• 2002

Some signals, such as in radar system, are transmitted as periodic pulse trains. If more than one pulse train are transmitted over the same communication channel, a problem is to separate them for source identification and extract each pulse train at the receiver. This is known as pulse train deinterleaving. In this paper, we present an approach for deinterleaving the pulse trains and extracting their periods combining the estimation of the frequency of each pulse train by DFT, CDIF/SDIF histogram and Sequence Search technique. Also, we present the result of deinterleaving pulse trains and extracting PRI in the complex environment which multiple signals are interleaved.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.6
• /
• pp.1141-1147
• /
• 2012

Electromagnetic analysis to design unclonable PUFs with frequency-dependant materials with Debye dispersion was considered. To simulate FDTD calculations consider that 1-D problem of pulsed plane wave traveling in free space normally incident on air-silicon material interface on dielectric substrate. The pulse traveling wave at a vacuum-medium interface was reflected, and transmitted wave was dissipated. As a result, 1-D PUF modeling with Debye dispersion on dielectric substrate structure can be applied and FDTD calculation for PUF modeling is a good approximation.

• Journal of Power Electronics
• /
• v.1 no.1
• /
• pp.26-35
• /
• 2001

In most inverter/converter applications SVPWM method is a preferred approach since it shows good characteristics in linear modulation range and waveform quality. In this paper, we propose a new carrier based SVPWM method for multi-level system, First, we survey the conventional carrier based SVPWM method, and investigate the problem of the conventional one for the multi-level system with the focus on the switching frequency harmonic flux trajectories. Finally, we propose a new carrier based SVPWM method that can reduce harmonic distortion. Simulation and experimental results are given for verification of the proposed SVPWM method.

• Proceedings of the KIPE Conference
• /
• 2001.12a
• /
• pp.11-14
• /
• 2001

Direct torque control (DTC) scheme provides a very quick torque response without the complex field-orientation block and inner current regulation loop. DTC is known as an appropriate scheme for high power induction motor drives because it can be used at lower switching frequency There are a major drawbacks with the application of DTC schemes it is large current harmonics due to flux drooping in a low speed range. In order to solve the problem, the fuzzy variable switching sector scheme are adopted in this paper. A meaningful contribution of this paper is to propose a simple realization scheme of the fuzzy variable switching sector technique. Experimental results show the effectiveness of this proposition.

• Proceedings of the KIPE Conference
• /
• 2001.12a
• /
• pp.135-138
• /
• 2001

In order to solve the problem of system efficiency reduced on account of two stage power conversion, we propose a series resonant full bridge inverter circuit for battery-fed microwave oven. This circuit has both a compact size and a light weight. Also, a frequency control adjusts power levels of the microwave oven. Operational principles are explained in detail. A proto-type inverter circuit with 1[kW] power consumption is built and tested for verifying the operation.