• Advances in concrete construction
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• v.1 no.3
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• pp.227-237
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• 2013

Modal testing, widely accepted and applied method for determining the dynamic characteristics of structures for operational conditions, uses known or unknown vibrations in structures. The method's common applications includes estimation of dynamic characteristics and also damage detection and monitoring of structural performance. In this study, the structural identification of concrete arch dams is determined using ambient vibration tests which is one of the modal testing methods. For the purpose, several ambient vibration tests are conducted to an arch dam. Sensitive accelerometers were placed on the different points of the crest and a gallery of the dam, and signals are collected for the process. Enhanced Frequency Domain Decomposition technique is used for the extraction of natural frequencies, mode shapes and damping ratios. A total of eight natural frequencies are attained by experimentally for each test setup, which ranges between 0-12 Hz. The results obtained from each ambient vibration tests are presented and compared with each other in detail. There is a good agreement between the results for all measurements. However, the theoretical fundamental frequency of Berke Arch Dam is a little different from the experimental.

• Journal of Daesoon Thought and the Religions of East Asia
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• v.2 no.1
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• pp.57-83
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• 2022

Numbers structure reality and define the way people live. Both in Daoism and in Daesoon Jinrihoe they signify key concepts, notably the cardinal numbers from one through nine that classify different dimensions of the cosmos. Beyond these, the number twenty-four plays an important role. In a temporal mode, it marks the divisions or seasonal periods of the year. Consisting of fifteen days each, these periods signal (and are named after) changes in dominant weather patterns and the position of the sun. Generally activated in the body through particular seasonal activities and dietary prescriptions, in Daoism they are also the root of a series of healing exercises and certain refinement practices of internal alchemy. In Daesoon Jinrihoe, moreover, they are activated by chanting a specific incantation that invokes the twenty-four divine rulers of the divisions, originally a group of Tang Dynasty officials that in nature and function resemble the spirit generals of the early Celestial Masters. Beyond this, the number twenty-four also applies to space. Not unlike the twenty-eight lunar stations or mansions, traditional cosmology acknowledges twenty-four directions, made up of six constellations each in the four cardinal directions, complete with starry deities and divine generals. Their powers are activated with the help of written characters rather than vocal incantations, using techniques common both in Daoism and Daesoon Jinrihoe.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.82-90
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• 2011

A novel class AB current subtracter(CS) and its application to Norton amplifier(NA) for low-power current-mode signal processing are designed. The CS is composed of a translinear cell, two current mirrors, and two common-emitter(CB) amplifiers. The principle of the current subtraction is that the difference of two input current applied translinear cell get from the current mirror, and then the current amplify through CB amplifier with ${\beta}$ times. The NA is consisted of the CS and wideband voltage buffer. The simulation results show that the CS has current input impedance of $20{\Omega}$, current gain of 50, and current input range of $i_{IN1}$ > $i_{IN2}{\geq}4I_B$. The NA has unit gain frequency of 312 MHz, transresistance of 130 dB, and power dissipation of 4mW at ${\pm}2.5V$ supply voltage.

• Journal of IKEEE
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• v.18 no.2
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• pp.220-227
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• 2014

This paper presents a control method of Single-Inductor Dual-Output DC-DC Converter using Common mode feedback and differential feedback loops. To generate duty used for differential mode feedback loop, this paper propose relative sawtooth circuit using current divider circuit which makes ramp signal with variable dead-time. Two outputs of the Single-Inductor Dual-Output DC-DC Converter are specified for 2.8 V and 4.2 V with input voltage 2.5 V. The maximum conversion efficiency of designed SIDO DC-DC Converter is 95% at total output power of 539mW. Cross regulations of Boost1 and Boost2 are 3.57% and 4% each, when increasing twice times output current.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.704-712
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• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to evaluate and monitor the effluent water quality ($BOD_5$, SS, T-N, and T-P) and operating conditions (Influent, SVI, SRT, and HRT) as process capable and stable parameters for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 7.7, 5.6, 10.8, and 1.6 mg/L. Trend analysis of influent $BOD_5$, SS, T-N, and T-P in APID process were illustrated that APID process need for more strong APID process management on the winter session, such as developing new intermediated aeration mode, operating methods, and managements strategy. At the application of control chart, the signal of uncommon effects at APID process was determined much higher existing control chart tntr conventional control chart in this study. These results indicate that conventional control chart has been collected and determined cleary signal at only stable situation. Therefore, newly developed APID process of dynamic control chart can be one of the useful tool for monitoring and management process.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.22-29
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• 2007

A 2.5Gb/s 2:1 multiplexer(MUX) IC using $0.18{\mu}m$ CMOS was designed and fabricated. Inductive peaking technology was used to improve the performance. On-chip micro spiral inductor was designed to maximize the inductive peaking effect without increasing the chip area much. The designed 4.7 nH micro-spiral inductor was $20\times20{\mu}m2$ in size. 2:1 MUX with and without micro spiral inductors were compared. The rise and fall time was improved more than 23% and 3% respectively using the micro spiral inductors for 1.25Gb/s signal. For 2.5 Gb/s signal, fall and rise time was improved 5.3% and 3.5% respectively. It consumed 61mW and voltage output swing was 1$180mV_{p-p}$ at 2.5Gb/s.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.2
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• pp.24-29
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• 2014

Digital mammography is the most common technique for the early detection of breast cancer. To diagnose the breast cancer in early stages and treat efficiently, many image enhancement methods have been developed. This paper presents a multi-scale contrast enhancement method in the Laplacian pyramid for the digital mammogram. The proposed method decomposes the image into the contrast measures by the Gaussian and Laplacian pyramid, and the pyramid coefficients of decomposed multi-resolution image are defined as the frequency limited local contrast measures by the ratio of high frequency components and low frequency components. The decomposed pyramid coefficients are modified by the contrast measure for enhancing the contrast, and the final enhanced image is obtained by the composition process of the pyramid using the modified coefficients. The proposed method is compared with other existing methods, and demonstrated to have quantitatively good performance in the contrast measure algorithm.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.2
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• pp.106-112
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• 2007

This paper proposes a hybrid architecture algorithm for fast computation of DCT and DFT via recursive factorization. Recursive factorization of DCT-II and DFT transform matrix leads to a similar architectural structure so that common architectural base may be used by simply adding a switching device. Linking between two transforms was derived based on matrix recursion formula. Hybrid acrchitectural design for DCT and DFT matrix decomposition were derived using the generation matrix and the trigonometric identities and relations. Data flow diagram for high-speed architecture of Cooley-Tukey type was drawn to accommodate DCT/DFT hybrid architecture. From this data flow diagram computational complexity is comparable to that of the fast DCT algorithms for moderate size of N. Further investigation is needed for multi-mode operation use of FFT architecture in other orthogonal transform computation.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1417-1427
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• 2019

In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a $20mm{\times}20mm{\times}5mm$ CZT crystal with $8{\times}8$ pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes $^{57}Co$, $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%-4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one $^{137}Cs$ source with various angular positions and two $^{137}Cs$ sources were performed. Individual and multiple sources of $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the $^{137}Cs$ experiments were approximately $7^{\circ}-9^{\circ}$ and $5{\times}10^{-4}-7{\times}10^{-4}$, respectively. The distortions of the source distribution were proportional to the offset angle.

• Progress in Medical Physics
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• v.13 no.3
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• pp.156-162
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• 2002

In this study, we attempted in preparing high precision EEG measuring equipment. To measure EEG in high efficiency, pre-amplifier should get high performance common mode rejection ratio. Also, separation amplifier is essential to eliminate common line noise. So, our study were pointed at elevating the efficiency of eliminating noise, user safety and low noise characteristics. Prepared high precision pre-amplifier for EEG was A/D converted to automatically classify $\alpha$ wave, $\beta$ wave and $\theta$ wave. And converted data were Fast Fourier Transformed with real time DSP (Digital Signal Processing). Clinical demonstrations were carried out with healthy students, aged between 20 to 26 who has no histories of illness. To recognize the efficiency of the EEG, prepared EEG were used with MS equipment in low stimulated state and high stimulated state. Then, we studied at the effect of sensitivity on brain wave. From this study, it is known that our EEG equipment is efficient in sensitivity evaluation and suitable stimulations for each psychological state are required.