• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2395-2402
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• 2013

An active-RC channel selection filter (CSF) with the bandwidth of 40MHz and the improved linearity is proposed in this paper. The proposed CSF is the fifth butterworth filter which consists of a first order low pass filter, two second order low pass filters of a biquad architecture, and DC feedback circuit for cancellation of DC offset. To improve the linearity of the CSF, a body node of a MOSFET for a switch is connected to its source node. The bandwidth of the designed CSF is selected to be 10MHz, 20MHz and 40MHz and its voltage gain is controlled by 6 dB from 0 dB to 24 dB. The proposed CSF is designed by using 40nm 1-poly 8-metal CMOS process with a 1.2V. When the designed CSF operates at the bandwidth of 40 MHz and voltage gain of 0 dB, the simulation results of OIP3, in-band ripple, and IRN are 31.33dBm, 1.046dB, and 39.81nV/sqrt(Hz), respectively. The power consumption and layout area are $450{\times}210{\mu}m^2$ and 6.71mW.

• Journal of Korean Foot and Ankle Society
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• v.1 no.1
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• pp.43-50
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• 1997

The tarsometatarsal joint complex is formed by articulation of the five metatarsal bases with the three cuneiform bones and the cuboid bone. Fracture-dislocation of tarsometatarsal area are difficult to recognize on standard radiographs. The exact diagnosis is occasionally delayed. As a result, improper treatment and late sequelae remains. We decided to make a study of patients with normal foot radiographs on 200 cases. Standard radiographic evaluation was used to study the normal variants of the foot and to evaluate the coincided alignment of the lisfranc joint. Accurate accessment on AP & lateral & $30^{\circ}$ oblique projection of radiographs are very adventageous & important, and next final outcome was detected. : 1. Coincided alignment below 1mm and unfolded lisfranc joint on AP projection was well visalized on 1st cuneiform-metatarsal lateral border and 2nd cuneiform-metatarsal medial border. 2. Coincided alignment below 1mm and unfolded lisfranc joint on oblique projection was well visualized on 2nd cuneiform-metatarsal lateral border and 3rd cuneiform-metatarsal medial border and 3rd cuneform-metatarsal lateral border. 3. More proximal location of 2nd lisfranc joint compared to another joint was 196 cases (98%). It is due to inceleration of 2nd metatarsal base between 3rd & 1st cuneiform. 4. 3rd lisfranc joint was volarward position compared to 2nd listranc on lateral projection at 191 cases (95.5%). It's due to anterior covexity of lisfranc joint. 5. Wide dorsal sided 2nd lisfranc is investigated at 189 cases (94.5%). Because of it. 2nd & 3rd lisfrances are mainly volar dislocated usually. 6. Notching on 5th metatarsal base is visible on 171 cases (85.5%). 7. 4th lisfranc joint had offset normally within $2\sim3mm$ at 98 cases (49%). 8. 5th Lisfranc joint had normally offset within $2\sim3mm$ at 99 cases (49.5%). 9. On lateral projection, slight dorsal location of cuneiform to metatarsal base is investigated at 82 cases (41%).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1167-1172
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• 2013

This paper presents a X-band doppler radar with high conversion gain using a self-oscillating-mixer(SOM) that oscillation and frequency mixing is realized at the same time. To improve phase noise of the SOM oscillator, a ${\lambda}/2$ slotted square patch resonator(SSPR) was proposed, which shows high Q-factor of 175.4 and the 50 % reduced circuit area compared to the conventional resonator. To implement the low power system, low biasing voltage of 1.7 V was supplied. To enhance the conversion gain of the SOM, bias circuit is configured near the pinch-off region of transistor, and the conversion gain was optimized. The output power of the proposed SOM was -3.16 dBm at 10.65 GHz. A high conversion gain of 9.48 dB was obtained whereas DC Power consumption is relatively low about 7.65 mW. The phase noise is -90.91 dBc/Hz at 100 kHz offset. The figure-of-merit(FOM) of the proposed SOM was measured as -181.8 dBc/Hz, which is supplier to other SOMs by more than about 7 dB.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.137-147
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• 2013

In this paper, an 1.2V 8b 1GS/s A/D Converter(ADC) based on a folding architecture with a resistive interpolation technique is described. In order to overcome the asymmetrical boundary-condition error of conventional folding ADCs, a novel scheme with an odd number of folding blocks and a fractional folding rate are proposed. Further, a new digital encoding technique with an arithmetic adder is described to implement the proposed fractional folding technique. The proposed ADC employs an iterating offset self-calibration technique and a digital error correction circuit to minimize device mismatch and external noise The chip has been fabricated with a 1.2V 0.13um 1-poly 6-metal CMOS technology. The effective chip area is $2.1mm^2$ (ADC core : $1.4mm^2$, calibration engine : $0.7mm^2$) and the power dissipation is about 350mW including calibration engine at 1.2V power supply. The measured result of SNDR is 46.22dB, when Fin = 10MHz at Fs = 1GHz. Both the INL and DNL are within 1LSB with the self-calibration circuit.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.7
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• pp.61-69
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• 2010

In this paper, an 1.2V 8b 800MSPS A/D Converter(ADC) with an odd number of folding block to overcome the asymmetrical boundary-condition error is described. The architecture of the proposed ADC is based on a cascaded folding architecture using resistive interpolation technique for low power consumption and high input frequency. The ADC employs a novel odd folding block to improve the distortion of signal linearity and to reduce the offset errors. In the digital block, furthermore, we use a ROM encoder to convert a none-$2^n$-period code into the binary code. The chip has been fabricated with an $0.13{\mu}m$ 1P6M CMOS technology. The effective chip area is $870{\mu}m\times980{\mu}m$. SNDR is 44.84dB (ENOB 7.15bit) and SFDR is 52.17dBc, when the input frequency is 10MHz at sampling frequency of 800MHz.

• Geophysics and Geophysical Exploration
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• v.22 no.4
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• pp.225-238
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• 2019

Migration velocity analysis (MVA) for creating optimum depth-domain velocities in seismic imaging was applied to marine long-offset multi-channel data, and the effectiveness of the MVA approach was demonstrated by the combinations of conventional data processing procedures. The time-domain images generated by conventional time-processing scheme has been considered to be sufficient so far for the seismic stratigraphic interpretation. However, when the purpose of the seismic imaging moves to the hydrocarbon exploration, especially in the geologic modeling of the oil and gas play or lead area, drilling prognosis, in-place hydrocarbon volume estimation, the seismic images should be converted into depth domain or depth processing should be applied in the processing phase. CMP-based velocity analysis, which is mainly based on several approximations in the data domain, inherently contains errors and thus has high uncertainties. On the other hand, the MVA provides efficient and somewhat real-scale (in depth) images even if there are no logging data available. In this study, marine long-offset multi-channel seismic data were optimally processed in time domain to establish the most qualified dataset for the usage of the iterative MVA. Then, the depth-domain velocity profile was updated several times and the final velocity-in-depth was used for generating depth images (CRP gather and stack) and compared with the images obtained from the velocity-in-time. From the results, we were able to confirm the depth-domain results are more reasonable than the time-domain results. The spurious local minima, which can be occurred during the implementation of full waveform inversion, can be reduced when the result of MVA is used as an initial velocity model.

• Korean Journal of Remote Sensing
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• v.28 no.5
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• pp.587-596
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• 2012

Verifying about eligibility of targeted site is necessary for execute Afforestation and Reforestation Clean Development Mechanism (A/R CDM) project which is followed by system of Kyoto protocol. The site have to be identified by which could not be in conformity with definition of forest. This study tried to propose a technology of classify for site selection of A/R CDM. We chose several parts of Yangpyeng as study area and applied LiDAR data and remotely sensed imagery for considering about tree height, degree of crown closure, and land area which 3 factors for identify forest. LiDAR data was used for offset the shortage of remotely sensed imagery that cannot perfectly determine the forest definition due to absence of 3-dimentional information, but can be obtained from LiDAR. Considering tree height, degree of crown closure, and land area simultaneously by moving window, classified fields to forest and non forest based on pixel size. As a result, 124.06 ha for suitable to doing plantation and approximately 357.02 ha are in negative. Technology that applied for analyzing will provide fundamental methodology not only site selection for A/R CDM, but will be utilized in other Kyoto protocol.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.665-677
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• 2021

This study analyzed the optimization method of forest management to enhance economic and public functions, as well as the interrelationship among timber production, carbon storage, and water conservation functions in Mt.Gari leading forest management zone. For these purposes, a forest management planning model was developed using Multi-Objective Linear Programming. The model had an objective function to maximize the total NPV (Net Present Value) of weighted timber production, carbon storage, water conservation, and constraints to limit the rate of change in timber production, percentage of each age-class and tree species area, percentage of conifers and broad-leaved trees area in each management zone, minimum timber production and timber sales amount. Based on the description of forest inventory and the comprehensive plan of Mt.Gari, we analyzed stand information and management constraints of the study area. We compared management alternatives using different weights in the objective function. Therefore, the total NPV was maximized in the alternative considering the three functions in equal proportion, rather than the alternatives of maximizing only one function. When all three functions were considered simultaneously, timber production offset the carbon storage and water conservation, and carbon storage and water conservation interacted synergistically. However, when considering only two of the three functions, all combinations of functions demonstrated tradeoffs with one other. Therefore, we discovered that by considering all three functions equally, rather than only one or two functions, the economic and public values of the study area can be maximized.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.2
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• pp.31-43
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• 2005

Four time points of the fractional area data during the 15 years of the highest group of land surface temperature and the lowest group of NDVl of the Kunsan city Chollabuk_do, Korea located beneath the Yellow sea coast, are observed and analyzed their correlations for the intention to detect the changes of urban land cover. As long as the effective contributions of satellite images in the continuous monitoring of the wide area for wide range of time period, Landsat-5 TM and Landsat-7 ETM+ artificial satellite images, acquisited over the Kunsan city area, are surveyed by the compared calibration after quantization and classification of the deviations between TM and ETM+ images substituted approved error correction thresholds such as gains and biases or offsets. This experiment and research applied Landsat-5 TM and Landsat-7 ETM+ artificial satellite images in change detection of urban land cover in urbanized Kunsan city, then detected strong and proportional correlation relationship between the highest group of land surface temperature and the lowest group of NDVI which exceeded R=(+)0.9478, so the proposed Correlation Analysis Model between the highest group of land surface temperature and the lowest group of NDVI will be able to give proof an effective suitability to the land city change detection monitoring.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.643-646
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• 2005

The gas hydrate exploration using seismic reflection data, the detection of BSR(Bottom Simulating Reflector) on the seismic section is the most important work flow because the BSR have been interpreted as being formed at the base of a gas hydrate zone. Usually, BSR has some dominant qualitative characteristics on seismic section i.e. Wavelet phase reversal compare to sea bottom signal, Parallel layer with sea bottom, Strong amplitude, Masking phenomenon above the BSR, Cross bedding with other geological layer. Even though a BSR can be selected on seismic section with these guidance, it is not enough to conform as being true BSR. Some other available methods for verifying the BSR with reliable analysis quantitatively i.e. Interval velocity analysis, AVO(Amplitude Variation with Offset)analysis etc. Usually, AVO analysis can be divided by three main parts. The first part is AVO analysis, the second is AVO modeling and the last is AVO inversion. AVO analysis is unique method for detecting the free gas zone on seismic section directly. Therefore it can be a kind of useful analysis method for discriminating true BSR, which might arise from an Possion ratio contrast between high velocity layer, partially hydrated sediment and low velocity layer, water saturated gas sediment. During the AVO interpretation, as the AVO response can be changed depend upon the water saturation ratio, it is confused to discriminate the AVO response of gas layer from dry layer. In that case, the AVO modeling is necessary to generate synthetic seismogram comparing with real data. It can be available to make conclusions from correspondence or lack of correspondence between the two seismograms. AVO inversion process is the method for driving a geological model by iterative operation that the result ing synthetic seismogram matches to real data seismogram wi thin some tolerance level. AVO inversion is a topic of current research and for now there is no general consensus on how the process should be done or even whether is valid for standard seismic data. Unfortunately, there are no well log data acquired from gas hydrate exploration area in Korea. Instead of that data, well log data and seismic data acquired from gas sand area located nearby the gas hydrate exploration area is used to AVO analysis, As the results of AVO modeling, type III AVO anomaly confirmed on the gas sand layer. The Castagna's equation constant value for estimating the S-wave velocity are evaluated as A=0.86190, B=-3845.14431 respectively and water saturation ratio is $50\%$. To calculate the reflection coefficient of synthetic seismogram, the Zoeppritz equation is used. For AVO inversion process, the dataset provided by Hampson-Rushell CO. is used.