• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.83.3-83
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• 2001

A method to adaptively control leg-ends trajectories of a five-legged walking robot, Cepheus-2, has been developed in terms of a kind of a table look-up method. Cepheus-2 is a five-legged robot with a pentagonal body with two joints of each leg. The robot control system has a hierarchical autonomic-integrated architecture with a main computer (PC), a manager and servo modules. Being given the goals of walking by the main computer, the manager module assigns a type of leg-end trajectories of which data are described with the work space coordinates for the legs. Every servo module generates the joint angle data. In steady walking of the robot on flat floor without obstacle, two joints have to generate the assigned trajectory and five legs ...

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.165-171
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• 2021

Vehicular Ad hoc Network (VANET) is an extension paradigm of moving vehicles to communicate with wireless transmission devices within a certain geographical limit without any fixed infrastructure. The vehicles have most important participation in this model is usually positioned quite dimly within the certain radio range. Fuzzy based multi-hop broadcast protocol is better than conventional message dissemination techniques in high-mobility VANETs, is proposed in this research work. Generally, in a transmission range the existing number of nodes is obstacle for rebroadcasting that can be improved by reducing number of intermediate forwarding points. The proposed protocol stresses on transmission of emergency message projection by utilization subset of surrounding nodes with consideration of three metrics: inter-vehicle distance, node density and signal strength. The proposed protocol is fuzzy MHB. The method assessment is accomplished in OMNeT++, SUMO and MATLAB environment to prove the efficiency of it.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.329-339
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• 2022

Small cells, particularly femtocells, are regarded a promising solution for limited resources required to handle the increasing data demand. They usually boost wireless network capacity. While widespread usage of femtocells increases network gain, it also raises several challenges. Interference is one of such concerns. Interference management is also seen as a main obstacle in the adoption of two-tier networks. For example, placing femtocells in a traditional macrocell's geographic area. Interference comes in two forms: cross-tier and co-tier. There have been previous studies conducted on the topic of interference management. This study investigates the principle of categorization of interference management systems. Many methods exist in the literature to reduce or eliminate the impacts of co-tier, cross-tier, or a combination of the two forms of interference. Following are some of the ways provided to manage interference: FFR, Cognitive Femtocell and Cooperative Resource Scheduling, Beamforming Strategy, Transmission Power Control, and Clustering/Graph-Based. Approaches, which were proposed to solve the interference problem, had been presented for each category in this work.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.163-171
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• 2022

Online services are widely spread, and their use increases day by day. As COVID-19 spread and people spent much time online, fraud scams have risen unexpectedly. Manipulation techniques have become more effective at swindling those lacking basic technological knowledge. Unfortunately, a user needs a quorum. The interest in preventing scammers from obtaining effective quality service has become the most significant obstacle, increasing the variety of daily Internet platforms. This paper is concerned with analyzing purchase data and extracting provided results. In addition, after examining relevant documents presenting research discussing them, the recommendation was made that future work avoids them; this would save a lot of effort, money, and time. This research highlights many problems a person may face in dealing with online institutions and possible solutions to the epidemic through theft operations on the Internet.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.638-647
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• 1996

Robot manipulators for harvesting fruits must be controlled to track the desired path of end-effector to avoid obstacles under the consideration of collision free area and safety path. This paper presents a robot path control algorithm to secure a collision free area with the recognition of work environments. The flexible space, which does not damage fruits or branches of tree due to their flexibility and physical properties , extends the workspace. Now the task is to control robot path in the extended workspace with the consideration of collision avoidance and velocity limitation at the time of collision concurrently. The feasibility and effectiveness of the new algorithm for redundant manipulators were tested through simulations of a redundant manipulator for different joint velocities.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.216-222
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• 2013

For reducing greenhouse gases, many countries carried out a series of activities not only at home but abroad. Particularly, after the release of the Kyoto Protocol, either nation or companies' participation was intensified, due to endow to responsibility of emission limits. This study focused on reforestation CDM work in Goseong Gun based on clean development system. Obstacle factors of land eligibility could be distinguished to three periods: before December 31th 1989, present and future. The obstacle before December 31th 1989 was that land cover of study area hardly illustrated by Landsat image, due to the low resolution, which were confirmed by a document of Grassland Composition Permission instead. The problem of current land eligibility is that the area of trees presence are difficult to be determined as forest or not. The boundary of forest in strata was identified, using 3-Dimensional Cartography Machine and aerial photograph. Land eligibility would still have obstacle whether the study area with trees presence has potentiality to be forest in the future at situation in absence of reforestation project. This was resolved by prediction of tree growth using stem analysis during execution of the project at study area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.498-508
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• 2019

This is a comparative descriptive research conducted to compare work obstacles and safety culture perceptions of elderly welfare facility employees in Korea and Japan. The number of subjects are total 680 including 460 Japanese employees, working at elderly welfare facility in city 'N', and 220 Korean employees in city 'A' and 'S' of province 'K'. This study had been conducted from April 1, 2018 to August 30, 2018 and the data was analyzed by x2-test, t-test, ANOVA. As a result, work obstacles were korea and japan, there were no statistically significant differences between two groups. In the safety culture perceptions, employees of elderly welfare facility in Korea showed significantly higher level of safety culture perception than employees of that in Japan. furthermore, it is revealed in both countries that the less work obstacles they have, the higher safety culture perceptions they get. And it is a work obstacles that affects safety culture perceptions. Lastly, it is expected that the result of this study can be used as basic data for the improvement of working environment and for the strategy development in human resource management to enhance the safety culture perceptions and to reduce work obstacles.

• Korean Journal of Child Care and Education Policy
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• v.12 no.3
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• pp.3-27
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• 2018

The purposes of this study were to examine a tendency of kindergarten teachers' daily work performance and to explore their perceptions on the reality and efficiency of working hours. 273 public and private kindergarten teachers completed questionnaires. The findings of the study are as follows. First, kindergarten teachers carried out an average of 1.41 duties per a 30-minute segment, and there were some differences in their duties between public and private teachers. Second, as a key reason of their lack of preparation time for class, public teachers indicated much administrative work, whereas private teachers indicated many events and common work. In addition, for the work duties that require supporting staff, public teachers pointed out clerical work, whereas private teachers named event-related duties. Third, in terms of efficiency of their working hours, both public and private teachers highlighted excessive workload as a key obstacle; public teachers also indicated the shortage of supporting staff, while private teachers indicated many event-related duties and lack of directors' leadership. These findings imply that it is important to maintain an optimum level of workload for kindergarten teachers, to secure preparation time for class, to increase work efficiency, and to provide support specific to kindergarten types.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.176-180
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• 2002

During the last two decades the laser beam has progressed from a sophisticated laboratory apparatus to an adaptable and viable industrial tool. Especially, in its welding mode, the laser offers high travel speed, low distortion, and narrow fusion and heat-affected zones (HAZ). The principal obstacle to selection of a laser processing method in production is its relatively high equipment cost and the natural unwillingness of production supervision to try something new until it is thoroughly proven. The major objective of this work is focused on the combined features of gas tungsten arc and a low-power cold laser beam. Although high-power laser beams have been combined with the plasma from a gas tungsten arc (GTA) torch for use in welding as early as 1980, recent work at the Ohio State University has employed a low power laser beam to initiate, direct, and concentrate a gas tungsten arcs. In this work, the laser beam from a 7 watts carbon monoxide laser was combined with electrical discharges from a short-pulsed capacitive discharge GTA welding power supply. When the low power CO laser beam passes through a special composition shielding gas, the CO molecules in the gas absorbs the radiation, and ionizes through a process known as non-equilibrium, vibration-vibration pumping. The resulting laser-induced plasma (LIP) was positioned between various configurations of electrodes. The high-voltage impulse applied to the electrodes forced rapid electrical breakdown between the electrodes. Electrical discharges between tungsten electrodes and aluminum sheet specimens followed the ionized path provided by LIP. The result was well focused melted spots.

• Journal of the Korean GEO-environmental Society
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• v.21 no.6
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• pp.19-25
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• 2020

In the recent downtown works, there are frequent cases where the work on existing piles is impossible due to the influence from lack of space and surrounding environment. In such cases, there has been growing cases of using the micropile method that is available to work with the small equipment and asserts the bearing capacity of the existing piles. The micropile method is a type of drilled shaft with the diameter of a pile to be around 75 mm~300 mm that, even for a case where it has certain surrounding structure, foundation and spatial obstacle, there is almost no work difficulty and the work is feasible under all types of soil conditions. In addition, the work can be done in places where the ceiling of the building is low with less vibration and noise in the work process that such method is significantly used for foundation reinforcement of existing buildings. With respect to the motion characteristics that are changed depending on the foundational characteristics or when the micropile is applied with compression or tensile force, there is very few studies conducted. Therefore, under this study, through the data analysis of the field loading test regarding the micropile worked in the fields, it clarifies the settlement and characteristics of bearing capacity following the embedded condition of the ingredients and piles that consist the foundation if the compression and tensile force are applied to the micropile, and by facilitating the statistical analysis program, SAS, to carry out the analysis on the main elements influencing on settlement of the micropile and bearing capacity.