• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.5
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• pp.21-29
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• 1992

This paper proposes a new MAC propocol for high-speed MAN. The proposed protocol is based on the P$_1$-persistent tranmission scheme and each node calculates the transmission probability periodically by using delay information(DI). A window mechanism for the calculation of message delay in each node is proposed to improve the adaptability of the proposed protocol to traffic changes. The capactiy of the proposed protocol is analyzed. The simulation results show that the proposed protocol gives fair message delay under heavy load conditions and, when the transmission speed or distance is increased, the message delay variation of the proposed protocol is less than that of IEEE 802.6 DQDB.

• International Journal of Industrial Entomology and Biomaterials
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• v.48 no.1
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• pp.1-12
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• 2024

Silk sericin, a natural protein from silkworm cocoons, is emerging as a multifunctional biomaterial in biomedicine, particularly in tissue engineering and wound healing. Recent studies have highlighted its biocompatibility, biodegradability, and potential for chemical modification, which allows it to be incorporated into various scaffold architectures. This review article synthesizes current research, including the development of sericin-based hydrogel scaffolds for tissue engineering and sericin's role in enhancing wound healing. Key findings demonstrate sericin's ability to refine scaffold porosity and mechanical strength, expedite tissue healing, and reduce bacterial load in wounds. The integration of sericin into novel bioactive dressings and its use in peripheral nerve injury repair are also discussed, showcasing its adaptability and efficacy. The convergence of these studies illustrates the broad applications of sericin, from scaffold design to clinical interventions, making it a promising material in regenerative medicine and tissue engineering, with the potential to improve patient outcomes significantly.

• Steel and Composite Structures
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• v.43 no.2
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• pp.139-152
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• 2022

Steel-reinforced concrete (SRC) L-shaped column is the vertical load-bearing member with high spatial adaptability. The seismic behavior of SRC L-shaped column is complex because of their irregular cross sections. In this study, the hysteretic performance of six steel truss reinforced concrete L-shaped columns specimens under the combined loading of compression, bending, shear, and torsion was tested. There were two parameters, i.e., the moment ratio of torsion to bending (γ) and the aspect ratio (column length-to-depth ratio (φ)). The failure process, torsion-displacement hysteresis curves, and bending-displacement hysteresis curves of specimens were obtained, and the failure patterns, hysteresis curves, rigidity degradation, ductility, and energy dissipation were analyzed. The experimental research indicates that the failure mode of the specimen changes from bending failure to bending-shear failure and finally bending-torsion failure with the increase of γ. The torsion-displacement hysteresis curves were pinched in the middle, formed a slip platform, and the phenomenon of "load drop" occurred after the peak load. The bending-displacement hysteresis curves were plump, which shows that the bending capacity of the specimen is better than torsion capacity. The results show that the steel truss reinforced concrete L-shaped columns have good collapse resistance, and the ultimate interstory drift ratio more than that of the Chinese Code of Seismic Design of Building (GB50011-2014), which is sufficient. The average value of displacement ductility coefficient is larger than rotation angle ductility coefficient, indicating that the specimen has a better bending deformation resistance. The specimen that has a more regular section with a small φ has better potential to bear bending moment and torsion evenly and consume more energy under a combined action.

• Journal of Biosystems Engineering
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• v.43 no.1
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• pp.1-13
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• 2018

Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission's power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission's gear, bearing, and oil seal. The motor's power was input in the transmission's input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.419-426
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• 2017

Recently, the transportation of dangerous explosive goods is increasing, which makes vehicle blasting accidents a potential threat for the safety of bridge structures. In addition, blasting accidents happen more easily when earthquake occurs. Excessive dynamic response of bridges under extreme loads may cause local member damage, serviceability issues, or even failure of the whole structure. In this paper, a new explosion-proof and aseismic system is proposed including cable support damping bearing and steel-fiber reinforced concrete based on the existing researches. Then, considering one 40m-span simply supported concrete T-bridge as the prototype, through scale model test and numerical simulation, the dynamic response of the bridge under three conditions including only earthquake, only blast load and the combination of the two extreme loads is obtained and the applicability of this explosion-proof and aseismic system is explored. Results of the study show that this explosion-proof and aseismic system has good adaptability to seism and blast load at different level. The reducing vibration isolation efficiency of cable support damping bearing is pretty high. Increasing cables does not affect the good shock-absorption performance of the original bearing. The new system is good at shock absorption and displacement limitation. It works well in reducing the vertical dynamic response of beam body, and could limit the relative displacement between main girder and capping beam in different orientation so as to solve the problem of beam falling. The study also shows that the enhancement of steel fibers in concrete could significantly improve the blast resistance of main beam. Results of this paper can be used in the process of antiknock design, and provide strong theoretical basis for comprehensive protection and support of girder bridges.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.51-58
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• 2002

A electronic business user is increased rapidly, and load of a electronic business system and network traffic are increased rapidly. Also, the data which included an audio and video is increasing in a electronic business system gradually, and According to this an Internet service businessman is paying for an enormous cost for management of a system and a maintenance of a line. It is brought a delay of a response speed about a service wish of a Web customer this system load and network traffic raise. Also, this decreases customer satisfaction and becomes an important factor to decrease competitive power of an e-business enterprise. In this study, we proposed the electronic business system that improved answer delay time about a Web customer in an e-business system based on the .net which was a the latest version of Microsoft company, and analyzed performance of a proposal system through an experiment. In the experiment result, the system that proposed it can have response time to have been improved and fast adaptability about various requests of a Web customer. Also, in a proposed system, a decrease gets a delay of a response speed to occur because of the multiple user done.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.5
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• pp.499-506
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• 2010

Recently, a great deal of attention have been directed to the use of alternative fuels as a means to reduce vehicular emissions. As one of the promising alternative fuels, bio-diesel has advantages of a wide adaptability without retrofit of diesel engine. It is also effective enough to reduce CO, THC, $SO_x$, polycyclic aromatic hydrocarbons (PAHs) and PM. In this study, we investigated the emission characteristics of biofuels between different operating conditions, i.e., engine speed (1,400 rpm and 2,300 rpm), engine load (10% and 100%), bio-diesel blending (BD0, BD5 and BD20), and recirculation (EGR) rate of exhaust gas (0% and 20%). Relative performance of the system was evaluated mainly for the greenhouse gases ($CH_4$, $N_2O$ and $CO_2$). In addition, emission characteristics of ND-13 mode were also tested against both greenhouse gases and other airborne pollutants under emission regulation. The relative composition of bio-diesel has shown fairly clear effects on the emission quantities of CO, THC, and PM emission, although it was not on $NO_x$ and greenhouse gases. EGR rate has shown trade-off characteristics between $NO_x$ and PM.

• Journal of Power Electronics
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• v.17 no.1
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• pp.282-293
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• 2017

There exists a strong coupling between real and reactive power owing to the complex impedances in droop based islanded microgrids (MGs). The existing virtual impedance methods consider improvements of the impedance matching for sharing of the voltage controlled power (VCP) (reactive power for Q-V droop, and real power for P-V droop), which yields a 1-DOF (degree of freedom) tunable virtual impedance. However, a weak impedance matching for sharing of the frequency controlled power (FCP) (real power for $P-{\omega}$ droop, and reactive power for $Q-{\omega}$ droop) may result in FCP overshoots and even oscillations during load transients. This in turn results in VCP oscillations due to the strong coupling. In this paper, a 2-DOF tunable adaptive virtual impedance method considering impedance matching for both real and reactive power (IM-PQ) is proposed to improve the power sharing performance of MGs. The dynamic response is promoted by suppressing the coupled power oscillations and power overshoots while realizing accurate power sharing. In addition, the proposed power sharing controller has a better parametric adaptability. The stability and dynamic performances are analyzed with a small-signal state-space model. Simulation and experimental results are presented to investigate the validity of the proposed scheme.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.205-214
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• 2024

This paper delves into the application of Gestalt psychology principles in logo design. It analyzes how these principles refine design elements to bolster the efficiency and impact of visual communication. Drawing from Gestalt psychology perspectives, the theoretical foundations and application methods of logo design simplification strategies are discussed. Through the analysis of Gestalt psychology effects in various types and styles of logo designs, this study compares the applicability and differences of logo design simplification strategies under different cultural and social contexts. Furthermore, it evaluates their role and value in enhancing the innovativeness and communicative impact of logo designs. The findings suggest that strategies informed by Gestalt psychology significantly improve the organization rules within logo designs, such as the relationship between figure and ground, proximity, similarity, and continuity. Thereby they enhance perceptual clarity, cognitive load, and aesthetic satisfaction. Moreover, these strategies promote creative thinking and problem-solving abilities in logo design. The results indicate that simplified design methods not only enhance aesthetic appeal but also improve the adaptability and recognizability of logos across different media and environments. This approach aligns with the minimalist and flat design trends of today's information age, meeting the evolving needs and aesthetic preferences of consumers.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.439-452
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• 2003

Mobile agent is one of the good technologies for overcoming network load and latency in distributed applications, and it may be a promising way of base technology of distributed applications because of its high adaptability for various network environments. In this paper, a mobile agent programming system, called HUMAN, is designed and implemented efficient use in various distributed applications based on mobile agents. HUMAN supports such high level utilities as file searhing, addressing by groups of nodes, storing path information, storing search information, and thus it gives us high easiness in agent-based programming. And it provides various itinerary modes and flexible reply modes for easy adaptation to given network environment. It also provides a management server for registering and active agents. Thus it can be efficiently applied for such varous distributed applications as searching distributed information, remote control, and file sharing in networks. A simple electronic commerce system is designed is designed and implemented as a HUMAN based illustrative application.