• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.2
• /
• pp.65-71
• /
• 2018

In order to make the underwater vehicle carry out the mission in a submarine environment, it is needed to plan a safe and efficient route to a given destination and prevent the autonomous submersible from colliding with obstacles while moving along the planned route. The function of collision avoidance makes the travel distance of the autonomous submersible longer. Moreover, it should move slowly near to obstacles against their moving disturbance. As a result, this invokes the degradation of the navigation efficiency in the process of collision avoidance. The side effect of the collision avoidance is not ignorable in the case of high congested environments such as the coast with many obstacles. In this paper, we suggest a path planning method which provides the route with minimum travel time considering collision avoidance in congested environment. For the purpose, we define environmental congestion map related to geometric information and obstacles. And we propose a method to consider the moving cost in the RRT scheme that provides the existing minimum distance path. We verified that the efficiency of our algorithm with simulation experiments.

• Journal of Korean Society for Quality Management
• /
• v.32 no.2
• /
• pp.1-14
• /
• 2004

As environmental issues have been become critical concerns of business, many domestic small and medium enterprises(SME's) are rapidly accepting environmental management systems(EMS) that confirm ISO 14001 guidelines. The purpose of this paper is to present the results of an empirical study carried out on a sample of certified SME's with the aim of identifying obstacles encountered in adopting ISO 14001 standards and the impact of environmental systems on corporate performance after implementation of the ISO 14001 registration process. Data from this study show that the vast majority of respondents reported environmental improvements related to the implementation of an ISO 14001 EMS, especially in the area of employees' participation of the environmental management and responsibilities for reducing negative impacts, energy and resource conservation, materials reuse, and raising top management commitment. The greatest obstacles for implementing the ISO 14001 standard are lack of cooperation and a scarcity of resources such as personnel, money, and time. Results of this study serve as a reference point understanding the problems in the implementation of ISO 14001 in other small and medium firms.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1491-1495
• /
• 2004

For the evaluation of the mobile robot performance in complex environments, the experimental approach in an actual physical environment has been commonly taken. In the physical experimental approach, however, it is quite difficult to define the proper environment for the evaluation due to the lack of commonly agreed characteristics of the test environment. Particularly the number of combinations of types and physical parameters of the obstacles that the mobile robot is expected to deal with is practically unlimited. In an effort to simplify and improve the effectiveness of the evaluation process, we propose an evaluation method using decomposed environmental elements, where we evaluated the performance of the robot for a small group of simple and decomposed obstacle components, for examples projection and slope, instead of a large group of complicated random obstacles. The paper describes a set of simple obstacle models and performance parameters that we have chosen for the effective evaluation process. As an alternative to the physical experimental evaluation approach, in this paper, we used a virtual evaluation environment where the robot and the physical test environment has been modeled using a commercial multi-body dynamics analysis packaged called RecurDyn.

• Journal of Environmental Science International
• /
• v.19 no.7
• /
• pp.917-929
• /
• 2010

This paper aims to find out the statistical characteristics of the weather related railroad accidents and incidents. Data from Korea Railroad Operation Information System(KROIS) and Korea Railroad Accidents reports during 1996-2008 were used to investigate the occurrence frequency of railroad accidents and operation obstacles and their association with weather phenomena. The results are as follows; The occurrence frequency of railroad accidents and operation obstacles decrease gradually, and most of railroad accidents is a railroad traffic accidents. The amount of damages by a railroad weather-related accidents is higher than those of the railroad accidents and operation obstacles. It was also found that weather events influencing the railroad weather-related accidents and incidents are rainfall, snowfall, lightning, winds. And they caused a railroad weather-related accidents and incidents, such as railway obstruction, signal failure, and power supply failure. Therefore we need research about threshold review and a quantitative and qualitative analysis of a railroad weather-related accidents and incidents according to climate change.

• Proceedings of the KIEE Conference
• /
• 1998.11b
• /
• pp.514-516
• /
• 1998

A Mobile Robot should be able to navigate safely in the workspaces without any additional human's helps. In this paper, a method to generate the safe path to avoid the unknown obstacles using the pre-knowledge of the workspaces was proposed. For the efficiency of the algorithm, it is proposed to model the obstacles as the line segments in numerical map, which can reduce the required memory size and give the simple forms. To make the environments map, we used the Hough transform and the sonar measurements is converted to the set of line segments by Hough transform. In this algorithm, the subgoals are generated to avoid the obstacles until a mobile robot arrives the final position using the proposed environmental model.

• Korean journal of applied entomology
• /
• v.22 no.2 s.55
• /
• pp.147-159
• /
• 1983

In general, herbicides have been classified according to selectivity, mobility. time of application, methods of application, mode of action and chemical property and structure. However, there was no generally accepted classification system for practical use in the field. The primary processes affected by the majority of herbicides are the growth process through cell elongation and/or cell division, the photosynthetic process specifically the light reaction, the oxidative phosphorylation and the integrity of the membrane systems. The usual approach in the study of the mechanism by which herbicides kill or inhibit the growth of plants is to initially determine the morphological phototoxicity systems, The mechanism by which a herbicide kills a plant or suppresses its development is actually the resultant effect of primary and secondary(or side) effects. In most instances, the death of the plant is due to the secondary effects. To induce the desired response, a herbicide must be able to gain entry into the plants and once inside, to be transported within the plant to its site(s) of activity in concentrations great enough. Obstacles to the entry and movement of herbicides in plants are generally classified by leaf and soil obstacles, translocation obstacles and biochemical obstacles, and these obstacles are also strongly influenced by plant species and by environmental factors such as light, temperature, rainfall and relative humidity. And hence, in most instances, results obtained from laboratory or greenhous vary from those of field experiment. Author attempted to classify herbicides from the field experiment using the two-dimensional ordination analysis to obtain practical information for selecting effective herbicides or to choose effective herbicide combinations for increasing herbicidal efficacy or reducing the chemical cost. Based on this two-dimensional diagram, desired herbicides or combinations were selected and further investigated for the interaction effects whether these combinations are synergistic, additive or antagonistic. From the results, it was concluded that these new approach could possibly be give more comprehensive informations about effective use of herbicide than any other systems.

• Journal of Environmental Science International
• /
• v.30 no.1
• /
• pp.19-28
• /
• 2021

To reduce pollution, decrease the production of carbon dioxide, and to maintain a secure supply of energy, interest continues to grow in the area of renewable energy especially since there is a finite supply of cheap oil. Wind energy is one of the most viable options to consider and supply part of the energy needed to reduce dependence on foreign oil. However, it is difficult to predict the wind speed in an environment with many obstacles such as buildings and trees and getting accurate dimensions of those obstacles is difficult particularly on sloped mountainous terrain. In this study a drone was used to create a 3-D map of the campus of the Catholic University of Pusan. The dimensions and elevations for the 3-D map were used to make a model of the school campus in the CFD program Envi-met. Simulations were run for five different wind directions and 4 different elevations to find the location that would give the highest electrical output for a wind turbine. When considering all of these variables it was found that the optimal location was above the Student Union which had a 40% higher wind speed and could produce 274% more electrical power than the original wind speed.

• Journal of the Korean Chemical Society
• /
• v.65 no.4
• /
• pp.268-278
• /
• 2021

The purpose of this study is to subdivide responsive teaching types proposed in the previous study in order to observe the change in the responsive teaching types in teacher educational programs, and to identify factors that impede changes in responsive teaching types. To this end, an educational program including introduction of responsive teaching, case analysis of responsive teaching, individual assignments and group discussions on facilitator type educational scenarios is provided for chemistry teachers who participated in a chemistry education course established in a graduate school of education. Based on previous research, when the teacher's teaching method was analyzed as evaluator, transfer, guide and facilitatore, a type that could not be classified was observed. In this study, responsive teaching types were added by adding two types: explorer and interpreter. In addition, through individual assignments and group discussion data, we could observe the factors that hinder teachers' responsive teaching changes. The obstacles that impede the change to responsive teaching were classified into teacher factors, student factors, and environmental factors. Among the obstacles, teacher factors include a belief in teacher-led instruction, a belief in the role of a teacher as a transfer of knowledge, a belief that the curriculum should be followed, a lack of understanding of the teacher about students, and a lack of the teacher's ability to lead student-led expansion. The student factor was distrust of the student's competence. Also, as an environmental factor, there was an educational environment such as multi-students class. Effective teacher education on responsive teaching can be achieved only when the perception related to these obstacles can be removed.

• Physical Therapy Korea
• /
• v.18 no.3
• /
• pp.16-25
• /
• 2011

This study aimed to evaluate factors related to the ability of ambulatory patients with cerebral palsy (CP) to walk over vertical and horizontal obstacles. Twenty patients with spastic CP who were able to walk independently for at least 10 m with or without walking devices were recruited for the study. Participants were required to walk over small obstacles (1, 4, and 8 cm in height or width; total of 6 conditions). A 'fail' was recorded when either the lower limbs or the walking device contacted the obstacle. Linear regression analyses were used to determine the effects of age, sex, walking devices, eyeglasses, subtype (hemiplegia or diplegia), ankle foot orthoses, functional level, and score of body mass index on the ability of obstacle crossing. Fifteen participants (75%) failed to adequately clear the foot or walking device over obstacles in at least 1 condition. The chance of failure in crossing vertical obstacle was affected by the use of ankle foot orthoses, eyeglasses, gender, and CP subtype (p<.05). The failure rate crossing horizontal obstacle was affected by CP subtype. These findings suggest that rehabilitation procedures should (1) consider the clinical characteristics of patients in order to prepare them to be more independent while performing daily activities, and (2) incorporate environmental conditions that patients encounter at home and in the community.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.2
• /
• pp.243-250
• /
• 2008

The coverage algorithm based on Boustrophedon path has been known to be the most efficient in places without or less obstacles If the map of an environmental area thru SLAM algorithm can be obtainable. However, the efficiency of the coverage algorithm based on Boustrophedon path drops drastically when obstacles are complex. In this paper, we propose and implement a new algorithm, which we call Group-k, that efficiently handles the complex area. The Group-k algorithm groups the obstacles and prioritizes the covering sequences with complex rank of the groups. Implementation-based experiments show about 20% improved performance when applying the nor- algorithm, compared to the Boustrophedon path algorithm.