• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.6 s.109
• /
• pp.562-573
• /
• 2006

It is required to reduce the peak-to-average power ratio(PAPR) in an orthogonal frequency division multiplexing system or a multicarrier system. And it is needed to eliminate the transmission of the side information in the Partial Transmit Sequences. So, in this paper, a new technique is proposed, where the subcarriers used for the multiple signal representation are only utilized for the reduction of PAPR to eliminate the burden of transmitting the side information. That is, it is proposed by taking the modified minimization criteria of partial transmit sequences scheme instead of using the convex optimization or the fast algorithm of tone reservation(TR) technique As the result of simulation, the PAPR reduction capability of the proposed method is improved by 3.2 dB dB, 3.4 dB, 3.6 dB with M=2, 4, 8(M is the number of partition in the so-called partial transmit reduction sequences(PTRS)), when the iteration number of fast algorithm of TR is 10 and the data rate loss is 5 %. But it is degraded in the capability of PAPR reduction by 3.4 dB, 3.1 dB, 2.2 dB, comparing to the TR when the data rate loss is 20 %. Therefore, the proposed method is outperformed the TR technique with respect to the complexity and PAPR reduction capability when M=2.

• Journal of the Korean Vacuum Society
• /
• v.4 no.S1
• /
• pp.102-107
• /
• 1995

We review the copper CVD line, via fill properties, and CMP line resistance. With CVD, trenches and vias with high aspect ratio(above 3) can be filled completely. Sputtering-reflow technique, a new method to filling copper into lines, is also reviewed to compare the CVD process.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1199-1202
• /
• 2003

In this research, microfabrication technique using localized electrochemical deposition is presented. Electric field is localized near the tip end region by applying ultra short pulses. Platinum tip is used as the counter electrode and copper is deposited on the copper substrate in 0.5 M CuSO$_4$ and 0.5 M H$_2$SO$_4$ electrolyte. The deposition characteristics such as size, shape, and structural density according to pulse duration and applied voltage are investigated. Micro-columns less than 10 $\mu\textrm{m}$ in diameter are fabricated using the presented technique. The process can be potentially used for three dimensional metal structure fabrications with micrometer feature size.

• Honam Mathematical Journal
• /
• v.38 no.4
• /
• pp.833-847
• /
• 2016

We are interested in the problem of finding the Hausdorff distance between two objects in ${\mathbb{R}}^2$, or in ${\mathbb{R}}^3$. In this paper, we develop an algorithm for computing the Hausdorff distance between two ellipses in ${\mathbb{R}}^3$. Our algorithm is mainly based on computing the distance between a point $u{\in}{\mathbb{R}}^3$ and a standard ellipse $E_s$, equipped with a pruning technique. This algorithm requires O(log M) operations, compared with O(M) operations for a direct method, to achieve a comparable accuracy. We give an example,and observe that the computational cost needed by our algorithm is only O(log M).

• Ocean Systems Engineering
• /
• v.9 no.4
• /
• pp.391-407
• /
• 2019

Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.11
• /
• pp.186-194
• /
• 2004

In this research, microfabrication technique using localized electrochemical deposition (LECD) with ultra short pulses is presented. Electric field is localized near the tool tip end region by applying a few hundreds of nano second pulses. Pt-Ir tip is used as a counter electrode and copper is deposited on the copper substrate in 0.5 M CuSO$_4$ and 0.5 M H$_2$SO$_4$ electrolyte. The effectiveness of this technique is verified by comparison with LECD using DC voltage. The deposition characteristics such as size, shape, surface, and structural density according to applied voltage and pulse duration are investigated. The proper condition is selected from the results of the experiments. Micro columns less than 10 $\mu$m in diameter are fabricated using this technique. The real 3D micro structures such as micro pattern and micro spring can be fabricated by this method. It is suggested that presented method can be used as an easy and inexpensive method for fabrication of microstructure with complex shape.

• ETRI Journal
• /
• v.31 no.5
• /
• pp.601-603
• /
• 2009

This letter presents a high performance 2.4 GHz two-stage power amplifier (PA) operating in the temperature range from $-30^{\circ}C$ to $+85^{\circ}C$ for IEEE 802.11g, wireless local area network application. It is implemented in InGaP/GaAs hetero-junction bipolar transistor technology and has a bias circuit employing a temperature compensation technique for error vector magnitude (EVM) performance. The technique uses a resistor made with a base layer of HBT. The design improves EVM performance in cold temperatures by increasing current. The implemented PA has a dynamic EVM of less than 4%, a gain of over 26 dB, and a current less than 130 mA below the output power of 19 dBm across the temperature range from $-30^{\circ}C$ to $+85^{\circ}C$.

• Journal of information and communication convergence engineering
• /
• v.14 no.4
• /
• pp.268-271
• /
• 2016

An efficient inductive switching noise suppression technique for mixed-signal integrated circuits (ICs) using standard CMOS digital technology is proposed. The proposed design technique uses a parallel RC circuit, which provides a damping path for the switching noise. The proposed design technique is used for designing a mixed-signal circuit composed of a ring oscillator, a digital output buffer, and an analog noise sensor node for $0.13-{\mu}m$ CMOS digital IC technology. Simulation results show a 47% reduction in the on-chip inductive switching noise coupling from the noisy digital to the analog blocks in the same substrate without an additional propagation delay. The increased power consumption due to the damping resistor is only 67% of that of the conventional source damping technique. This design can be widely used for any kind of analog and high frequency digital mixed-signal circuits in CMOS technology

• Korean Journal of Head & Neck Oncology
• /
• v.15 no.2
• /
• pp.194-199
• /
• 1999

Introduction: Since 1996, Dr. James Norman has successfully performed mimimally invasive radio-guided parathyroidectomy(MIRP) using intraoperative nuclear mapping with $^{99m}Tc$ sestamibi scanning and radioactivity detection probe. Objectives: We aimed to introduce this new surgical technique and evaluate it's efficacy by our own experiences. Method: From May to October 1999, five consecutive patients with primary hyperparathyroidism underwent parathyroidectomy by using modified MIRP technique. $^{99m}Tc$ sestamibi scanning was performed 1.0 or 1.5 hour before operation. After intraoperative localization of the tumor under the guidance of quantitative gamma counting with a NEVIGATOR probe, an unilateral small skin incision(3.0-4.0cm) was placed. Without a skin flap, the strap muscle was directly divided with the use of a Harmonic scalpel. After careful dissection, the parathyroid tumor was removed. Result: In all patients, a single adenoma could be easily detected and removed by this new technique. Mean incision length was 3.2cm(3.0-4.0cm) and operative time ranged from 40 to 110minute. All the patients were discharged within 2 days of surgery without any complication. Conclusion: This new operative technique could become the most minimally invasive alternative to the standard operative procedure for parathyroid adenoma.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.12
• /
• pp.1798-1802
• /
• 2013

We present a technique for measuring low resistance ranges of a decade resistor with a 4-Terminal connection. With the technique the accuracy of 0.8 % was obtained for a 1 $m{\Omega}$ resistance of the decade resistor. We suggested a proper pattern 4-Terminal measurement results with several 4-Terminal pattern and adapters. Additionally, we should that precise measurements for low resistance can be made usung a digital multimeter(DMM) only.