• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.174-179
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• 2013

This paper presents a capacitor loaded tunable bandpass chip filter using multiple split ring resonators (MSRRs) with two transmission zeros. To obtain high selectivity and minimize the chip size, asymmetric feed lines are adopted to make a pair of transmission zeros located on each side of passband. Compared with conventional filters using cross-coupling or source-load coupling techniques, the proposed filter uses only two resonators to achieve high selectivity through a pair of transmission zeros. In order to optimize selectivity and sensitivity (insertion loss) of the filter, the effect of the position of asymmetric feed line on transmission zeros and insertion loss is analyzed. The SOI-CMOS switched capacitor composed of metal-insulator-metal (MIM) capacitor and stacked-FETs is loaded at outer rings of MSRRs to tune passband frequency and handle high power signal up to +30 dBm. By turning on or off the gate of the transistors, the passband frequency can be shifted from 4GH to 5GHz. The proposed on-chip filter is implemented in 0.18-${\mu}m$ SOI CMOS technology that makes it possible to integrate high-Q passive devices and stacked-FETs. The designed filter shows miniaturized size of only $4mm{\times}2mm$ (i.e., $0.177{\lambda}g{\times}0.088{\lambda}g$), where ${\lambda}g$ denotes the guided wave length of the $50{\Omega}$ microstrip line at center frequency. The measured insertion loss (S21)is about 5.1dB and 6.9dB at 5.4GHz and 4.5GHz, respectively. The designed filter shows out-of-band rejection greater than 20dB at 500MHz offset from center frequency.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.127-132
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• 2011

We acquired and interpreted more than 650 km of high-resolution seismic reflection profiles in the Hupo Basin, offshore east coast of Korea at $37^{\circ}N$ in the East Sea (Japan Sea) to image shallow and basement deformation. The seismic profiles reveal that the main depocenter of the Hupo Basin in the study area is bounded by the large offset Hupo Fault on the east and an antithetic fault on the west; however, the antithetic fault is much smaller both in horizontal extension and in vertical displacement than the Hupo Fault. Sediment infill in the Hupo Basin consists of syn-rift (late Oligocene. early Miocene) and post-rift (middle Miocene.Holocene) units. The Hupo Fault and other faults newly defined in the Hupo Basin strike dominantly north and show a sense of normal displacement. Considering that the East Sea has been subjected to compression since the middle Miocene, we interpret that these normal faults were created during continental rifting in late Oligocene to early Miocene times. We suggest that the current ENE direction of maximum principal compressive stress observed in and around the Korean peninsula associated with the motion of the Amurian Plate induces the faults in the Hupo Basin to have reverse and right-lateral, strike-slip motion, when reactivated. A recent earthquake positioned on the Hupo Fault indicates that in the study area and possibly further in the eastern Korean margin, earthquakes would occur on the faults created during continental rifting in the Tertiary.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.171-174
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• 1999

Background: Hyperhidrosis of the palms, axillae and face has a strong negative impact on social and professional life. The present existing non-operative therapeutic options seldom give sufficient relief and have a transient effect. A definitive cure can be obtained by upper thoracic sympathectomy. However, this is offset by the occurrence of a high rate of side effects, such as embarrassing compensatory sweating. Material and Method: From Sep. 1997 to Feb. 1998, 89 cases of the needle(2 mm) thoracoscopic thoracic sympathicotomy were performed. The second thoracic ganglion was resected by cutting with a endoscissors. Result: A bilateral procedure takes less than 25 min and requires just one night in hospital. There have been no mortality or life-threatening complications. One patient(<2%) required intercostal drainage because of pneumothorax. Primary failure occurred in one cases(<2%) and recurrent hyperhidrosis occurred in no cases. The patients with failure was successfully re-sympathicotomy. At the end of postoperative follow-up(median 3 months), 96.6% of the patients were satisfied. Compensatory sweating occurred in 57 cases(64.0%) with fourteen of those cases classified as either embarrassing in 10 cases(11.2%) or disabling in 4 cases(4.5%). Conclusion: Endoscopic transthoracic sympathicotomy is an efficient, safe and minimally invasive surgical method for the treatment of palmar and craniofacial hyperhidrosis.

• Journal of the Korean earth science society
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• v.36 no.6
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• pp.501-511
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• 2015

This study suggests a method of alleviating global warming by the increase of the Earth surface albedo through Artificial Sea ice Increasing (ASI) over the Available Freezing Areas (AFA). The method is developed based on the fact that the large sea surface area in or near the Arctic and the Antarctic has no ice even though both water and air temperatures are below zero and the artificial sea ice generation is thus available. The mean energy of $0.85Wm^{-2}$, which was suspected of adding to the earth by the global warming effect was calculated to offset at once when the sea ice area about $4.09{\times}10^6km^2$ was additionally increased. In addition, three techniques for producing ice plates on the sea surface (using ships, installation apparatus, and floating matter such as Green Cell Foam) for ASI were proposed. According to the result of simple analysis using the energy balance model, when ASI was maximally operated only for 3 months (September, October, and November) over AFA, it is expected that the annual mean temperature of earth surface would be decreased about $0.11^{\circ}C$ in the following year. On the other hand, in case of generating the artificial sea ice in all four seasons, a risk of triggering snowball earth was detected.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.471-482
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• 2015

In this paper, design and implementation of the 94 GHz Gunn oscillator and the evaluation of the maximum power of the Gunn diode used in the oscillator are presented. The 94 GHz Gunn oscillator is used InP Gunn diode and designed employing a WR-10 waveguide. The designed oscillator is fabricated through machining and its performance is measured. The fabricated oscillator shows an oscillation frequency of 95 GHz, output power of 12.64 dBm, and phase noise of -92.7 dBc/Hz at 1 MHz offset frequency. To evaluation the maximum power of the InP Gunn diode used in oscillator, the oscillator structure is modified to a structure having a diaphram. The height of thick diaphram which is used in the oscillator is varied. As a result, an oscillator has several different load impedances, which makes it possible to plot $G_L-V^2$ plot at the post plane. Using the $G_L-V^2$ plot, the maximum power of used Gunn diode including post is computed to be 16.8 dBm. Furthermore using the shorted and zero bias Gunn diode, the post loss used for DC biasing can be computed. Using the two losses, The maximum power of a InP Gunn diode is computed to be 18.55 dBm at 95 GHz. This result is close to a datasheet.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.418-425
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• 2014

This paper presents a Ku-Band Doppler Radar System to measure respiration and heart rate. It was measured by using simultaneous radar and ECG(Electrocardiogram). Arctangent demodulation without dc offset compensation can be applied to transmitted I/Q(In-phase & Quadrature-phase) signal in order to improve the RMSE(Root Mean Square Error) about 50 %. The power leaked to receiving antenna from the transmitting antenna is always generated because of continuously opening the transceiver of CW(Continuous Wave) Doppler radar. As the output power increase, leakage power has an effect on the SNR(Signal-to-Noise Ratio) of the system. Therefore, in this paper, leakage cancellation technique that adds the signal having the opposite phase of the leakage power to the leakage power was implemented in order to minimize the decline of receiver sensitivity. By applying the leakage cancellation techniques described above, it is possible to measure the heart rate and respiration of the human at a distance of up to 35 m. the heart rate of the measured data at a distance of 35 m accords with the heart rate extracted from the ECG data.

• Strategy21
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• s.41
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• pp.333-370
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• 2017

북한의 SLBM 위협이 대한민국 안보에 미치는 영향에 대해 그동안 많은 논의가 있어 왔지만, 북의 잠수함에서 발사하는 탄도미사일이 보유한 진정한 위협에 대한 인식은 아직도 부족한 듯하다. 그 이유는 대부분의 논의가 북 SLBM 기술의 성숙도와 완성시기 등 기술적 수준에 관심이 치우쳐져 있기 때문이다. 핵전략과 억제전략의 관점에서 본다면 북한의 SLBM 개발은 한미동맹의 제1격에 대한 완벽한 제2격 능력 보유에 그 핵심이 있다. 즉 향후 개발될 북한의 SLBM은 평양 김정은 정권의 생존을 보장할 직접적이고 핵심적인 전력이 될 것이다. 이는 궁극적으로 한미 군사동맹과 북한의 현 군사력 균형을 깨뜨리고 앞으로 북의 군사도발 가능성을 더욱 높이는 결과를 가지고 올 것이다. 북의 핵전략은 현재 확증보복(assured retaliation) 단계로 발전하고 있으며, 결국에는 전쟁에 사용될 전술적 핵무기 능력(war-fighting capability)을 갖게 될 것이다. 이에 대한민국 해군은 우리의 강점을 활용하여 적의 약점을 공략할 수 있는 상쇄전략(offset strategy)을 개발하여야 한다. 북한의 현 제한된 잠수함 기술력과 대잠작전 능력을 고려할 때 한국해군은 수중영역에서의 공세적 대잠전(offensive ASW) 개념을 보다 발전시켜야만 할 것이다. 이는 미 해군이 냉전기간 중 소련해군 핵추진전략잠수함(SSBN) 대응을 위해 발전시킨 전략대잠전(strategic ASW) 개념에서 교훈을 얻을 수 있다. 미 해군은 소련 해군의 SSBN 을 억제하기 위해 공세적인 전략대잠전을 수행했고 그 결과 소련해군은 자국의 연안에서 벗어나지 못하는 요새전략(bastion strategy)를 추구할 수밖에 없었다. 당시 미 해군의 전략대잠전은 공격잠수함(SSN), 대잠초계기, 수중 탐지체계(SOSUS), 공격기뢰 등의 전력으로 구성되었다. 따라서 북한 SLBM 에 대한 한국해군의 전략개념은 북의 핵전략(제 2 격능력)을 억제하는 방향으로 정립되어야 하며, 이를 위한 해군력 건설은 대잠전 능력 강화에 초점을 맞추어야 한다. 우리 해군은 장기적으로 핵추진잠수함을 비롯하여 성능이 향상된 대잠초계기, 한반도 해역을 중심으로 한 미 해군의 SOSUS 와 유사한 수중탐지장비 그리고 장시간 수중작전이 가능한 무인잠수정(UUV)을 도입해야만 한다. 단기적으로는 현재 추진되고 있는KAMD 체계에 SM-3 를 보유한 이지스함을 포함시켜, 북 SLBM 에 대한 요격능력을 강화해야 할 것이다. 한미동맹은 북 핵전략의 핵심전력인 SLBM 개발에 대한 위협인식을 공유해야만 하다. 작전적 수준에서는 양국 해군 간 대잠전 및 대유도탄전 작전운용성 증대에 우선순위를 두고, 기존의 한미 간 연합작전능력 강화뿐 아니라 위기시를 대비하여 미일 간 구축되어 있는 대잠전 및 대유도탄전 능력도 활용할 필요가 있을 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12A
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• pp.2000-2011
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• 2001

In this Paper, we convert conventional low speed(1x, 6x) DVD systems designed by analog PLL(Phase Locked Loop) into digital PLL to operate at high speed systems flexibly, and present optimal DPLL model in high speed(20x) DVD systems. Especially, we focused on the design of DPLL that can overcome channel effects such as bulk delay, sampling clock frequency offset and asymmetry phenomenon in high speed DVD systems. First, the modified Early-Late timing error detector as digital timing recovery scheme is proposed. And the four-sampled compensation algorithm using zero crossing point as asymmetry compensator is designed to achieve high speed operation and strong reliability. We show that the proposed timing recovery algorithm provides enhanced performances in jitter valiance and SNR margin by 4 times and 3dB respectively. Also, the new four-sampled zero crossing asymmetry compensation algorithm provides 34% improvement of jitter performance, 50% reduction of compensation time and 2.0dB gain of SNR compared with other algorithms. Finally, the proposed systems combined with asymmetry compensator and DPLL are shown to provide improved performance of about 0.4dB, 2dB over the existing schemes by BER evaluation.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.505-512
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• 2016

Even though high performance concrete was developed according to the trend of bigger and higher of reinforced concrete building, the rheological evaluations such as viscosity, yield stress are not enough to use as input data to accomplish the numerical analysis for the construction design. So there are many problems in the harden concrete such as poor compaction, rock pocket and crack, etc. in the field. In this study, consistency curves were measured by the viscometer as hydration reaction time passed. At the same time the slump flow test and Vicat setting test were carried out for comparing with the results of rheological properties. The fluidity of the W/B 30% decreased as the increase of replacement ratio of blast furnace slag. But in case of W/B 40%, the replacement ration did not significantly influenced to the slump flow value with the passage of hydration time. By the replacement of blast furnace slag to cement, initial setting was delayed and the time gap between initial and final setting became shorten. Through the regression analysis using Bingham model, there are a sudden changes of viscosity and yield stress around initial setting in case of low W/B 30%. The increase of workability by the change of free water in cement paste was offset by the coating effect of impermeable layer in case of W/B 40%.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.34-41
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• 2011

This paper presents a wide tuning range, fine-resolution DCO (Digitally Controlled Oscillator) with an active inductor. In order to control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. In addition, the DCO gain needs to be calibrated digitally to compensate for gain variations. To cover the wide tuning range, an automatic three-step coarse tuning scheme is proposed. The DCO total frequency tuning range is 1.4 GHz (2.1 GHz to 3.5 GHz), it is 58 % at 2.4 GHz. An effective frequency resolution is 0.14 kHz/LSB. The proposed DCO is implemented in 0.13 ${\mu}m$ CMOS process. The total power consumption is 6.6 mW from a 1.2 V supply voltage. The phase noise of the DCO output at 2.4 GHz is -120.67 dBc/Hz at 1 MHz offset.