• Geomechanics and Engineering
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• v.30 no.5
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• pp.401-411
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• 2022

To obtain the dynamic mechanical properties, fracture modes, energy and brittleness characteristics of Furong Baijiao coal rock, the dynamic impact compression tests under 0, 4, 8 and 12 MPa confining pressure were carried out using the split Hopkinson pressure bar. The results show that failure mode of coal rock in uniaxial state is axial splitting failure, while it is mainly compression-shear failure with tensile failure in triaxial state. With strain rate and confining pressure increasing, compressive strength and peak strain increase, average fragmentation increases and fractal dimension decreases. Based on energy dissipation theory, the dissipated energy density of coal rock increases gradually with growing confining pressure, but it has little correlation with strain rate. Considering progressive destruction process of coal rock, damage variable was defined as the ratio of dissipated energy density to total absorbed energy density. The maximum damage rate was obtained by deriving damage variable to reflect its maximum failure severity, then a brittleness index BD was established based on the maximum damage rate. BD value declined gradually as confining pressure and strain rate increase, indicating the decrease of brittleness and destruction degree. When confining pressure rises to 12 MPa, brittleness index and average fragmentation gradually stabilize, which shows confining pressure growing cannot cause continuous damage. Finally, integrating dynamic deformation and destruction process of coal rock and according to its final failure characteristics under different confining pressures, BD value is used to classify the brittleness into four grades.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1835-1841
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• 2017

An improved single-phase full-bridge zero-voltage-switching inverter using a subtractive coupled magnetics is proposed in this paper. The proposed topology overcomes several drawbacks of the conventional ARCPI zero-voltage-switching inverter including two bulky capacitors which can cause problems such as the need for a protection circuit and voltage fluctuation of split capacitors. Also the proposed topology can reduce the number of devices required for ZVS through a simplified auxiliary circuit, thus achieving low cost and small volume and is applicable a modified unipolar PWM scheme. Detail mode analysis and design considerations are provided for optimal efficiency. In the end, the effectiveness and feasibility of the proposed topology are verified experimentally under various conditions.

• Progress in Superconductivity
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• v.3 no.1
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• pp.28-30
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• 2001

We studied the flux-flow current-voltage characteristics of microwave-generated fluxons formed in serially stacked intrinsic Josephson junctions fabricated on$ HgI_2$-intercalated $Bi_2$$Sr_2$$CaCu_2$O/8+x/(Bi2212) single crystals. With increasing the irradiation power of 73$\square$76 GHz microwave, the supercurrent branch became resistive and split into multiple sub -branches. Each sub-branch represented a specific mode of collective motion of Josephson fluxons. We also observed similar branch splitting In a mesa prepared on an underdoped Bi2212 single crystal in a static magnetic field.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.12
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• pp.3310-3329
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• 2023

This work designs an eighteen-channel bidirectional Intensity Modulation with Direct Detection (IM/DD) Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) system. The proposed system meets the requirement of the ITU-T 5G fronthaul link suggested design in G-series Recommendations-Supplement 66. The newly designed system, with a 25Gb/s/λ data rate (450Gbps as a system capacity), has been tested and simulated using OptiSystem V.19 software. The system has been evaluated by the BER with respect to variable the optical span and CW laser power. Based on the ITU-T recommendations, the simulation results demonstrate that this system might be used as an F1 and as an Fx 5G fronthaul link for functional split choices starting from options 1 to 7a. These options are required under 25Gbps/λ for each upstream and downstream link direction. Furthermore, the proposed system utilized a bidirectional single-mode optical fiber within short optical spans of up to 10 km. The proposed system is characterized by a low-cost, simple, DSP-free and amplifier-free system with a reasonable system capacity.

• Journal of Distribution Science
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• v.12 no.6
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• pp.67-79
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• 2014

Purpose - This study aims to accomplish three major research goals. First, it strives to change consumers' focus from peripheral routes to a central route of public service advertising related to the good health policy, without problematic effects, by influencing consumers' knowledge or involvement. Second, this study examines the elaboration likelihood model (ELM) and construal level theory (CLT). Specifically, we consider that the central route of ELM might correspond with the focal goal of CLT. Third, this study analyzes ELM through CLT. That is, ELM predicted that low involvement would take the peripheral route, and high involvement would take the central route. Research design, data, and methodology - This study consisted of three experiments. The first experiment had a 2×2 between-subject design. The subjects were university students and the research period was approximately one year. The first independent variable was the involvement of the overweight issue; this variable was measured and split by the median. The second independent variable was the temporal distance (near vs. distant future); this variable was manipulated. The second experiment also had a 2×2 between-subject design. The first variable was the involvement of cervical adenocarcinoma prevention, and was considered already manipulated by sex. Specifically, males had a low involvement of the disease, but females had high involvement. The second independent variable was priming (power vs. submissive). Power priming would induce abstract thinking, but submissive priming would take concrete processing. The third experiment had a 2×2×2 between-subject design. The first variable was cognitive depletion, and was manipulated by memorizing 9-digit numbers. The second and third independent variables were involvement and abstract thinking induction, such as prior experiments. Data were collected through questionnaires, and were analyzed by an SPSS program. Major hypotheses were tested by examining the interaction effects through ANOVA. Results - Major findings are as follows. First, even for low-involved consumers in the overweight category, distant future manipulation induced them to focus not on the peripheral route but on the central route of the public service advertisement. This result does not correspond to the typical ELM prediction. Second, under power priming, low-involved males of the cervical adenocarcinoma category focused on the peripheral route because of the induction to abstract thinking. This result replicated the first experiment, and confirmed the theoretical robustness. Third, high-involved females focused not on the central but on the peripheral route under the mixed condition of cognitive depletion and near future manipulation. Depletion consumed cognitive resources, and the processing mode of consumers changed from systematic to heuristic. Conclusions - ELM needs to be complemented through CLT in context of public service good health advertising. Specifically, the involvement of ELM may impact consumers' thinking mode (abstract vs. concrete), and the interaction effects may influence consumers' focus on advertising (central vs. peripheral route). This study's limitations were bounded subjects, limited stimuli, and somewhat weak external validity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1575-1580
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• 2011

A key factor in the study of hybrid vehicle is to enhance the usability of energy. The paper introduces the monitor and controlling technology of hybrid vehicle that can process the relevant information considering the structure of power system and driving strategies simultaneously, and can monitor its results. This technology, so called HEV algorithm analysis, has been applied to PRIUS THS made by Toyota Co. LTD. This model is adapted to parallel hybrid type. It has a somewhat comlex structure, but has several merits. It's energy loss is lower when conversing. and also it is easily applied to the conventional vehicle having a gasoline engine without any overall changing of its structure, and so on. This monitor and controlling technology is very useful to study on the various driving strategies of hybrid vehicle for maximizing the usability between engine and electric motor.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.783-798
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• 2004

An e-business client application in ubiquitous mobile computing environment may become disconnected from the enterprise server due to broken communication connections caused by the limitation of mobile computing environments(limited battery life of the mobile device, low bandwidth communication, incomplete wireless communication infrastructure, etc). It Is even Possible that mobile client application Intentionally operates in disconnected mode to reduce communication cost and the power consumption of the mobile device. We use “data hoarding” as a means of providing local autonomy to allow transactions to be processed and committed on the mobile host despite of disconnection. The key problem to this approach is the synchronization problem that serialize potentially conflicting updates from disconnected clients on master objects of the server database. In this paper, we present a new transaction synchronizing method that splits a transaction into a set of independent component transactions and give the synchronization priority on each component taking the possibility of use and conflicts in the server into consideration. Synchronization is performed component by component based un synchronization priority. After the Preferred component of a no bile transaction succeeds in synchronization with the server, the mobile transaction can pre-commit at server. A pre-committed transaction's updated value is made visible at server before the final commit of the transaction. The synchronization of the component with low synchronization priority can be delayed in adaption to wireless bandwidth and computing resources. As a result, the availability of important data updated by mobile client is increased and it can maximize the utilization of the limited wireless bandwidth and computing resources.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.248-253
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• 2005

We designed and fabricated a compact multi-mode interference (MMI) wavelength demultiplexer using the concept of 'Improved Quasi-State' modes. The output power and extinction ratio were improved by utilizing modal phase error which is specially occurred in low-index contrast. For a designed demultiplexer, the mode propagation analysis with effective index approximation shows significant improvement of extinction ratio to -25 dB for both $1.31{\mu}m\;and\;1.51{\mu}m$ wavelength region and the split-length was reduced about 1/5 of other MMI devices. The fabricated device shows successful characteristics for both 1.31 and $1.55{\mu}m$ wavelengths. These results demonstrate the potential of low-index materials system and the embossing process for photonic integrated circuits.