• Journal of Mechanical Science and Technology
• /
• v.20 no.6
• /
• pp.849-863
• /
• 2006

IBM (Immersed Boundary Method) with feedback momentum forcing was applied to stationary and moving bodies. The capability of IBM to treat the obstacle surfaces, especially with moving effect has been tested for two dimensional problems. Stationary and oscillating cylinders were simulated by using IBM based on finite volume method with Cartesian coordinates. For oscillating cylinder, lateral and vertical motions are considered, respectively. Present results such as time histories of drag and lift coefficients for both stationary and oscillating cases are in good agreement with previous numerical and experimental results. Also, the instantaneous wake patterns of oscillating cylinder with different oscillating frequency ratios well represented those of previous researches. More feasibility study for IBM has been carried out to two oscillating cylinders. Drag and lift coefficients are presented for two cylinders oscillating sinusoidally with phase difference of $180^{\circ}$.

• Ocean Systems Engineering
• /
• v.2 no.4
• /
• pp.271-287
• /
• 2012

Due to its large size, a ship is first divided into scores of blocks and then each block is constructed through various shops, such as the assembly shop, the painting shop, and the outfitting shop. However, each block may not be directly moved to the next shop and may be temporarily laid at a block stockyard because the working time in each shop is different from each other. If blocks are laid at the block stockyard without any planning, the rearrangement of the blocks by a transporter is required because the blocks have the different in and out time. In this study, a block layout method based on the genetic algorithm was proposed in order to minimize the rearrangement of the blocks in the block stockyard. To evaluate the applicability of the proposed method, it was applied to simple layout problems of the block stockyard. The result shows that the proposed method can yield a block layout that minimizes the total relocation cost of moving obstacle blocks in the block stockyard.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.16 no.6
• /
• pp.293-297
• /
• 2021

This paper presents how to create a 3D map and solve problems related to generating a global path planning for navigation. Map creation and localization were performed using the RTAB-Map package to create a 3D map of the environment. In addition, when the target point is within the obstacle space, the problem of not generating a global path was solved using the asr_navfn package. The performance of the proposed system is validated through experiments with a wheelchair-type robot.

• International journal of advanced smart convergence
• /
• v.8 no.2
• /
• pp.30-38
• /
• 2019

Recently, the spread of personal mobility has been rapidly increasing due to the development of environmentally friendly alternative transportation means. In addition, the level of battery technology is also rapidly developing, accelerating the popularization of personal mobility. Such personal mobility has convenience of location transfer, amusement, and high portability compared to other transportation devices. Most personal mobility, however, is made up of small wheels, which cannot overcome obstacles such as rugged roads or obstacles on the road. In this paper, to solve these problems, we tried to devise a device that can easily overcome obstacles by combining wheels with small moving means. The wheel size can be mounted on the front wheel of the small moving means in a protruding manner so that obstacles can be encountered before the front wheels and the safety and ride comfort of the running can be improved.

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

• Journal of the Korean Society of Systems Engineering
• /
• v.20 no.spc1
• /
• pp.108-118
• /
• 2024

As shared electric kick scooters spread to cities worldwide as a result of the proliferation of personal mobility, they have emerged as a significant social issue, impacting pedestrian and user safety, as well as urban aesthetics. In this study, we propose solutions to the unique problems associated with shared electric kick scooters, such as illegal parking, charging, and redistribution. Furthermore, we present research on supplementary services utilizing electric kick scooters in urban areas to enhance citizen safety and user satisfaction through the development of an autonomous electric kick scooter system structure and operational strategies. We suggest a low-cost autonomous electric kick scooter structure and propose AI processing, sensor fusion, and system operation methods to add autonomous capabilities to affordable electric kick scooters. Additionally, we propose operational systems and related technologies for offering various supplementary services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.10a
• /
• pp.224-226
• /
• 2016

With the technical development and rapid increase of private demand, the new market for unmanned vehicle combined with the characteristics of 'unmanned automation' and 'vehicle' is rapidly growing. Even though the pilot driving is currently allowed in some countries, there is no country that has institutionalized the formal driving of self-driving cars. In case of the existing vehicles, safety incidents are frequently happening due to the frequent malfunction of the rear sensor, blind spot of the rear camera, or drivers' carelessness. Once such minor flaws are complemented, the relevant regulations for the commercialization of self-driving car and small drone could be relieved. Contrary to the ultrasonic and laser sensors used for the existing vehicles, this paper aims to attempt the distance measurement by using the depth sensor. A depth camera calculates the distance data based on the TOF method calculating the time difference by lighting laser or infrared light onto an object or area and then receiving the beam coming back. As this camera can obtain the depth data in the pixel unit of CCD camera, it can be used for collecting depth data in real-time. This paper suggests to solve problems mentioned above by using depth data in real-time and also to design the obstacle avoidance system through distance measurement.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.29 no.1
• /
• pp.7-13
• /
• 2018

Objectives: Problem behaviors pose a great obstacle to daily functioning in children with neurodevelopmental deficits and are an important target for treatment. In this study, we translated the Behavior Problems Inventory (BPI)-01 into Korean language and tested its psychometric properties. Methods: We attained the approval of the BPI author and performed standard translation-back translation. Then, professional caregivers examined appropriateness according to cultural and situational contexts in order to make necessary modifications of the Korean version of the BPI. Results: The BPI-01, Korea-Scales of Independent Behavior-Revised (K-SIB-R), and Child Behavior Checklist were completed for 98 autistic spectrum disorder or intellectual development disorder participants (mean age=28.3, standard deviation=7.3, range=10.1-51.7). The inter-rater reliability of the BPI-01 was found to be high (r=0.992-1.000). As for the results for concurrent validity for subscale items of BPI-01 and scales of SIB, correlations between SIB and BPI-01 subscales were statistically significant (r=0.357-0.672). Discussion: The Korean version of the BPI-01 showed good psychometric properties with high reliability and sufficient convergent validity. Further examination of the validity of BPI-01 should be carried out with inclusion of younger aged children and a closer look at less frequently occurring symptoms.

• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.1
• /
• pp.270-285
• /
• 2017

This study is about the solution to solve the problem - aging of fisheries worker and exodus of young adult from fisheries. We tried to find out internal improvements which are necessary for overcoming issues. After that, research about inducements and institutional improvements to drive internal improvements has done. and Current policies of Korea for securing workforce in fisheries were examined especially for Gyeongsangnam-do by literature investigation and survey The main purpose of this study is, problems of policy in order to secure Fisheries managers, identify practical obstacle and the activities and management activities performance of training education. and it is to provide evidence to policy improvement. To achieve the purpose of this study, conducted studies are as below. This study is to investigate the educational performance of Fisheries managers and its impact on their business performance using SEM and SEM-Moderate-effect. In terms of the amount of impact on business performance, the level of educational achievement and management activity outcomes had the most impact followed by excellence of educational condition and programs distinction. Therefore, in order to inspire the motivation for learning and communicate the importance of such education to Fisheries communities, there is a need to introduce a variety of methods, professional facilities. The purpose of this research is to define the problems of the Fisheries Census of Korea and to make better policies for improvement. In order to complete the purpose, the research team has firstly conducted a survey in the six regions to reinvestigate the yes or no for accuracy of the primary data related to the Fisheries Census. Moreover, the team has defined the problems of the Fisheries Census through conducting a survey for the experts and users of the fisheries statistics. Also, the team has derived the short/long term improvement of Fisheries Census through out this survey.

• The KIPS Transactions:PartD
• /
• v.11D no.2
• /
• pp.351-360
• /
• 2004

Most mobile agents are migrated to many mobile agent systems by the sequential node migration method. However. in this case, if some problems such as host's fault or obstacle etc. happened, mobile agent falls infinity walt or orphan states. Therefore, it is difficult to get an expectation effect as use of other distribution technologies because the required time for networking between nodes increases. And so, many researches have been performed to solve this problems. However, most of methods decide node migration based on passive routing table or detour hosts which have some problems. Actually, the researches for reducing the total required time for networking are insufficient yet. In this paper, to reduce the required time for networking of mobile agent we design an active routing table based on the information of implemented objects which are registered in the meta-table of naming agent. And also, for user's keyword, we propose an replication model that replicates many agent object according to the information and number of object references corresponding to meta-table. Replicated objects are migrated to mobile agent systems in parallel and it provides minimized required time for networking.