• The Journal of Korea Robotics Society
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• v.7 no.2
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• pp.150-159
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• 2012

In this paper, we propose a cost-aware Rapidly-exploring Random Tree (RRT) path planning algorithm for mobile robots. A mobile robot is presented with a cost map of the field of interest and assigned to move from one location to another. As a robot moves, the robot is penalized by the cost at its current location according to the cost map. The overall cost of the robot is determined by the trajectory of the robot. The goal of the proposed cost-aware RRT algorithm is to find a trajectory with the minimal cost. The cost map of the field can represent environmental parameters, such as temperature, humidity, chemical concentration, wireless signal strength, and stealthiness. For example, if the cost map represents packet drop rates at different locations, the minimum cost path between two locations is the path with the best possible communication, which is desirable when a robot operates under the environment with weak wireless signals. The proposed cost-aware RRT algorithm extends the basic RRT algorithm by considering the cost map when extending a motion segment. We show that the proposed algorithm gives an outstanding performance compared to the basic RRT method. We also demonstrate that the use of rejection sampling can give better results through extensive simulation.

• The Korean Journal of Applied Statistics
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• v.17 no.2
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• pp.197-204
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• 2004

We have sent the 1000 hair samples to USA and received the results from USA because the programs for the interpretation of Tissue Mineral Analysis (TMA) result is not opened yet in Korea. Therefore, the study will analyze the relationship between the hair for Korean and minerals and make a classification system. To achieve the goal, first of all, we coded the results of patients and classified the analyzed results which are the interrelationship between the minerals and dietary situation and the heavy metals and diseases through the statistical methods. Finally we classified 8 metabolic type using decision tree classifier.

• Transactions on Electrical and Electronic Materials
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• v.18 no.6
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• pp.350-358
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• 2017

Recently, owing to increased interest in low-carbon energy supplies, renewable energy sources such as photovoltaics and wind turbines in distribution networks have received considerable attention for generating clean and unlimited energy. The presence of energy storage systems (ESSs) in the promising field of active distribution networks (ADNs) would have direct impact on power system problems such as encountered in probabilistic distributed generation (DG) model studies. Hence, the optimal procedure is offered herein, in which the simultaneous placement of an ESS, photovoltaic-based DG, and wind turbine-based DG in an ADN is taken into account. The main goal of this paper is to maximize the net present value of the loss reduction benefit by considering the price of electricity for each load state. The proposed framework consists of a scenario tree method for covering the existing uncertainties in the distribution network's load demand as well as DG. The collected results verify the considerable effect of concurrent installation of probabilistic DG models and an ESS in defining the optimum site of DG and the ESS and they demonstrate that the optimum operation of an ESS in the ADN is consequently related to the highest value of the loss reduction benefit in long-term planning as well. The results obtained are encouraging.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.990-1003
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• 2006

To cope with the change of railway safety environment and to prevent the catastrophic accident, the railway safety management system was established through the legislation of railway safety rules. And to audit and evaluate the accomplishment of railway safety rules by the railway operators, the Integrated Railway Safety Audit System(IRSAS) has been conducting. This study find out the strategy to stabilize the IRSAS by applying Theory of Constraints(TOC) Thinking Process. For meeting the IRSAS's goal of effective levelling up of railway safety, the two necessary conditions, 1)the secure of substantial safety through the IRSAS and 2)the execution of efficient IRSAS, should be fulfilled. Estimated undesirable effects(UDEs) from the IRSAS were identified, and 3 of them were selected for creating the requisite conflict clouds. Entities from these conflict clouds were synthesized into a core conflict cloud that foamed the base of Current Reality Tree. The strategic direction for change extracted from the conflict cloud is the reinforcement of IRSAS preparation system including the level up of operator's self audit, the deepening of preliminary survey, the establishment of complementing system of audit check list and the build up of auditor's specialization. These injection were logically validated via a Future Reality Tree and expected to be confirmed by further progressing of IRSAS.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.317-322
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• 2011

Korean adults' internet addiction diagnosis measure, K-scale developed by Korea National Information Society Agency (NIA), has composed of 4 categories including 20 items. This scale can diagnose user's internet addiction with individual's questionnaire items. Most of previous research works were tried to know reasons of internet addiction and to judge whether adolescents are addicted or not with their samples. In this research, it is the goal to find the key component to judge individual's internet addiction by using a decision tree in the data mining field and a principal component analysis in statistics. From the experimental results, we would discover that tolerance and preoccupation factor is the most important one to affect adult's internet addiction.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.285-292
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• 2019

Path planning is an important problem to solve in robotics and there has been many related studies so far. In the previous research, we proposed the Heterogeneous-Ants-Based Path Planner (HAB-PP) for the global path planning of mobile robots. The conventional path planners using grid map had discrete state transitions that constrain the only movement of an agent to multiples of 45 degrees. The HAB-PP provided the smoother path using the heterogeneous ants unlike the conventional path planners based on Ant Colony Optimization (ACO) algorithm. The planner, however, has the problem that the optimization of the path once found is fast but it takes a lot of time to find the first path to the goal point. Also, the HAB-PP often falls into a local optimum solution. To solve these problems, this paper proposes an improved ant-inspired path planner using the Rapidly-exploring Random Tree-star ($RRT^*$). The key ideas are to use $RRT^*$ as the characteristic of another heterogeneous ant and to share the information for the found path through the pheromone field. The comparative simulations with several scenarios verify the performance of the improved HAB-PP.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.134-134
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• 2022

Streamflow forecasting plays a crucial role in water resource control, especially in highly urbanized areas that are very vulnerable to flooding during heavy rainfall event. In addition to providing the accurate prediction, the evaluation of effects and importance of the input predictors can contribute to water manager. Recently, machine learning techniques have applied their advantages for modeling complex and nonlinear hydrological processes. However, the techniques have not considered properly the importance and uncertainty of the predictor variables. To address these concerns, we applied the GA-BART, that integrates a genetic algorithm (GA) with the Bayesian additive regression tree (BART) model for hourly streamflow forecasting and analyzing input predictors. The Jungrang urban basin was selected as a case study and a database was established based on 39 heavy rainfall events during 2003 and 2020 from the rain gauges and monitoring stations. For the goal of this study, we used a combination of inputs that included the areal rainfall of the subbasins at current time step and previous time steps and water level and streamflow of the stations at time step for multistep-ahead streamflow predictions. An analysis of multiple datasets including different input predictors was performed to define the optimal set for streamflow forecasting. In addition, the GA-BART model could reasonably determine the relative importance of the input variables. The assessment might help water resource managers improve the accuracy of forecasts and early flood warnings in the basin.

• Fashion & Textile Research Journal
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• v.9 no.5
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• pp.538-544
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• 2007

We usually try to accomodate ourselves to our nature surroundings interacting with nature. There fore I've decided to apply nature materials, esp. the pine to Hair Art as a way of expressing our feelings from Nature. 'Hair Art' is a follow-up study based on the various artistic point of view. There has been various works of 'Hair Art' with nature materials. However, it is rare to see a work of 'Hair Art' with the pine. That's why I've decided to study more about this. This study is a new experiment in 'Hair Art' against a conventional idea "Hair Art values practicability." Therefore, the primary goal of this study is to do much for the cause of learning in 'Hair Art' and encourages some development of 'Hair Art' industry. I've researched an image of a pine tree in art of Joseon Dynasty and contemporary art. Then I've tried to apply the image to a work of 'Hair Art'. First of all, in a view of expression technique for the symbolism of the pine, the artists in Joseon Dynasty drew pictures of a pine tree with a paintbrush but the modern artists make a new attempt from the thought of Modernism. We can find it in some photos. Next, to express traditional oriental idea such as 'unconventional and elegance', comtemporary artists chose the symbolism of the pine tree as an object of their works like pen and ink sketches from the thought of Modernism. Third, in a fusion style picture which contains features of both oriental paintings and western paintings and in a sexualism style picture that depicts a harmony of a male and a female as a shape of a pine, we can find colorful images of a pine tree and Their figurative beauty in art. Those are another symbols of the pine. In conclusion, the implication of the pine tree still hasn't changed even there are differences of drawings of pine tree in the past and the present. I've tried to combine these symbolic ideas of the pine with 'Hair Art' and made 5 hair styles. Throughout the process of researching this topic which is 'The Study of Hair Art Using The Symbolism of The Pine', I've realized that pine trees make it possible to express intrinsic tough spirit of human being and abundance in color and figurative beauty in art. I hope this can contribute to the field of 'Hair Art' and would become an important educational resource for further study.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.11
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• pp.765-778
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• 2013

This paper proposes a test case generation method for Stateflow model using the extended RRT method. The RRT method which has been popularly used for planning paths for complex systems also shows a good performance for test case generation. However, it does not consider the test coverage which is important for test case generation. The proposed extension method hires the concept of test goal achievement to increase test coverage and drives RRT extension in the direction that increases the goal achievement. Considering the concept, a RRT distance metric, random node generation method and modified RRT extension algorithm are proposed. The effectiveness of proposed algorithm is compared with that of the typical RRT algorithm through the experiment using the practical automotive ECUs.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.3
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• pp.19-31
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• 2017

Plants are the basis for sustainable green growth, and the value of existence and importance of trees including landscape Plants can't be emphasized enough. Therefore, they are precious living things thriving in all sorts of public services, and continuous civil complaints for justifiable compensation of landscape Plants are filed. First, the standard formula of planting intervals according to production target specifications is calculated using root-collar caliper and diameter at breast height, and apply (1) standard medium sized trees which have not yet reached commercialization [deciduous tree production goal (R(B) less than 6cm]= (target standard)= [target standard $R(cm){\times}15{\times}0.7$]. (2) In case of commercialization(R6~R10)= [target standard $R(cm){\times}15{\pm}5%$], (3) In case of more than R12= [target standard $R(cm){\times}15{\times}130%$] shall be applied. In case of using diameter at breast height (4) In case of commercialization(B6~B10)= [target standard $B(cm){\times}20{\times}15{\pm}5%$], (5) In case of more than B12= [target standard $B(cm){\times}20{\times}130%$] shall be applied. Second, appraisal methods based on tree classification of compensation for loss are classified according to planted locations. (1) landscape trees within a house=[price of arrival at the site+planting cost], (2) landscape trees in places such as arboretum=[management technology of tress + relocation expenses considering scarcity of the trees (3) landscape trees in a place of loads= [landscape tree production cost + work out added price. In case of producted landscape threes (4) landscape trees ready to be commercialized as sales loss.