• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.66-71
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• 2014

This paper presents an analog front-end integrated circuit (IC) for medical ultrasound imaging systems using standard $0.18-{\mu}m$ CMOS process. The proposed front-end circuit includes the transmit part which consists of 15-V high-voltage pulser operating at 2.6 MHz, and the receive part which consists of switch and a low-power low-noise preamplifier. Depending on the operation mode, the output driver in the transmit pulser can be reconfigured as the switch in the receive path and thus the area of the overall front-end IC is reduced by over 70% in comparison to previous work. The designed single-channel front-end prototype consumes less than $0.045mm^2$ of core area and can be utilized as a key building block in highly-integrated multi-array ultrasound medical imaging systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1911-1918
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• 2014

The increase of input resources, such as labor and equipment, in a construction project causes workspace interference between activities and it influences on the productivity and quality of construction activities. To solve this problem, many studies related to the workspace interference have been performed, however they verified the workspace concerning with only the geometric location of activities or generated the shape of workspace by a whole object concept not separated units of detailed operations. It is difficult for project manager to reasonably analyze the workspace conflict, because the size of workspace cannot reflect the characteristics of an activity and input time of a resource. This paper presents a methodology that can generate three-dimensional models in order to optimize the workspace shape and size by considering with the characteristics of each activity and input time of each resource. The suggested method can be used for the active BIM system that optimizes the workspace conflict without additional construction duration and for the searching algorithm of optimized moving path for construction equipment.

• The Korean Journal of Financial Management
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• v.22 no.1
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• pp.147-179
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• 2005

It is frequently said that mortgage-backed securities (MBS) of different security designs are issued in an attempt to meet the varying needs and expectations of investors. If this is true indeed, MBS of complicated risk-return characteristics are likely to be priced higher than MBS of simple risk-return characteristics we. We test this implication by establishing a recombining binomial interest rate prepayment model with a burnout effect embedded. More specifically, we compare the relative values (utilities) of a pass-through and a PAC- Support collateralized mortgage obligation(CMO), and theoretically show why and how the CMO is more highly valued than is the pass-through. The model is established such that mortgage prepayment is a function of the current value of, and the past path of, the mort-gage market rate. Since we work on not the total value of the two MBS but the value of each tranche of either MBS, the test results could be robust to slightly different versions of similar tests, which may be done in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1295-1304
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• 2010

This paper proposes a fault-tolerant data aggregation which provides energy efficient and reliable data collection in wireless sensor networks. The traditional aggregation scheme does not provide the countermeasure to packet loss or the countermeasure scheme requires a large amount of energy. The proposed scheme applies caching and re-transmission based on the track topology to the adaptive timeout scheduling. The proposed scheme uses a single-path routing based on the traditional tree topology at normal, which reduces the dissipated energy in sensor nodes without any countermeasure against packet loss. The proposed scheme, however, retransmits the lost packet using track topology under event occurrences in order to fulfill more accurate data aggregation. Extensive simulation work under various workloads has revealed that the proposed scheme decrease by 8% in terms of the dissipated energy and enhances data accuracy 41% when the potential of event occurrence exists as compared with TAG data aggregation. And the proposed scheme decrease by 53% in terms of the dissipated energy and shows a similar performance in data accuracy when the potential of event occurrence exists as compared with PERLA data aggregation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.170-177
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• 2009

In this paper, we propose the structures of the NBTC (Narrow-Beam Trisector Cell) and the WBTC(Wide-Beam Trisector Cell) in which directional antennas both at the base station and at the relay station are used. We analyze and compare total capacity of the both systems taking the co-channel interference into consideration for two channel models. Through analysis, we find the effect of LOS (Lind of Sight) path to the total capacity of NBTC structure and that of WBTC structure. Our work may be useful as a guideline to control the interference for the next generation mobile communication and WiBro systems using multi-hop relays.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.3
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• pp.300-309
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• 2003

The Japanese developed the first Car navigation system in 1981 with the advent of Honda, which was known as the car inertial navigation system. Now days, It is possible to search the shortest route to and from places and arrival time using the internet via cell phone to the driver based on GIS and GPS. However, even with a good navigation system, it losses the shortest route when there is an average speed of the vehicle being between S-15 kilometers. Therefore, in order to improve the vehicle waiting time and average vehicle speed, we are suggesting an optimal green time algorithm using fuzzy adaptive control, where there are different traffic intersection lengths, and lanes. In this paper, to be able to assist the driver and forecast the optimal traffic information with regards to the road conditions; dangerous roads, construction work and estimation of arrival time at their destination using internet.

• Journal of dental hygiene science
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• v.6 no.2
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• pp.139-145
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• 2006

This study aimed to examine the factors affecting education satisfaction of dental hygiene students by conducting surveys on a total of 1,840 first, second, and third year dental hygiene students enrolled in 6 colleges in Gyeonggi-do, Chungcheong-do, and Jeolla-do, and then using SPSS WIN 12.0 to analyze the results. The following results were obtained. 1. In terms of differences in satisfaction for each year, "department satisfaction", "major satisfaction", "facility satisfaction", and "lecture satisfaction" showed statistically significant differences (p < 0.05). 2. In terms of differences in satisfaction for each region, all of the categories - "department satisfaction", "major satisfaction", "facility satisfaction", "lecture satisfaction", and "lecturer satisfaction" - showed statistically significant differences (p < 0.05). 3. In terms of differences in satisfaction for the department of dental hygiene, the following factors showed statistically significant differences: general knowledge of dental hygiene (p = .000), channel of knowledge of dental hygiene (p = .001), timeframe of making decision to study dental hygiene (p = .025), motive for choosing dental hygiene (p = .000), career path after graduation (p = .016), and number of years at work after graduation (p = .0000).

• Journal of Digital Convergence
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• v.17 no.12
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• pp.329-336
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• 2019

This study is a descriptive research study that examines the level of terminal care nursing care and the effects on terminal nursing in the internal and external control beliefs of nurses in the nursing geriaic hospital.. The subjects consisted of 442 nurses, and data were collected through structured questionnaires.. The data were analyzed with descriptive that used SPSS WIN 22.0, and AMOS 5.0 statistical program was hypothetical model and path analysis of research hypothesis. As a result, terminal care of geriatric hospital nurses was statininificant to the terminal care stress, fatigue and locus of internal & external control. and the higher the internal control belief, the less stress of the terminal care and the higher the terminal care performance As a result, this study providers a more terminal care performance, It is considered that nursing hospital nurses who develop strategic programs and terminal care nursing will need to provide quality nursing education and work environment improvement.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.9
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• pp.19-27
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• 2002

Characteristics of interconnect lines considering underlayer geometries of a silicon substrate and crossing metal lines are experimentally analyzed through elaborately devised patterns. In this work, test patterns for transmission lines having several kinds of underlayer geometries were devised, and the signal characteristics and responses are measured by S-parameter and time domain reflection meter (TDR). The patterns were designed and fabricated with a deep-submicron CMOS DRAM technology having 1 Tungsten and 2 Aluminum metals. From the analysis of measured results on the patterns, it is founded that the effects of underlayter line structures on line parameters (especially line capacitance and resistance) and signal distortions occurred from them cannot be negligible. The results provide useful and insightful understanding in the skew balance of package leads and global signal lines such as high-speed clock and data lines.

• Structural Engineering and Mechanics
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• v.17 no.1
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• pp.51-68
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• 2004

Since the linear elastic fracture analysis has been proved to be insufficient in predicting the failure of strain hardening materials, a number of fracture concepts have been studied which remain applicable in the presence of plasticity near a crack tip. This work thereby presents a new finite element model to predict the elastic-plastic crack-tip field and fatigue life of center-cracked panels(CCP) with ductile fracture under large-scale yielding conditions. Also, this study has been carried out to investigate the path-dependence of J-integral within the plastic zone for elastic-perfectly plastic, bilinear elastic-plastic, and nonlinear elastic-plastic materials. Based on the incremental theory of plasticity, the p-version finite element is employed to account for the accurate values of J-integral, the most dominant fracture parameter, and the shape of plastic zone near a crack tip by using the J-integral method. To predict the fatigue life, the conventional Paris law has been modified by substituting the range of J-value denoted by ${\Delta}J$ for ${\Delta}K$. The experimental fatigue test is conducted with five CCP specimens to validate the accuracy of the proposed model. It is noted that the relationship between the crack length a and ${\Delta}K$ in LEFM analysis shows a strong linearity, on the other hand, the nonlinear relationship between a and ${\Delta}J$ is detected in EPFM analysis. Therefore, this trend will be depended especially in the case of large scale yielding. The numerical results by the proposed model are compared with the theoretical solutions in literatures, experimental results, and the numerical solutions by the conventional h-version of the finite element method.