• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.723-730
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• 2015

In this paper, a location tracking compensation algorithm based on the Least-Squares Method ($LCA_{LSM}$) was proposed to improve the autonomous tracking efficiency for the docent robot in exhibition hall, and the performance of the $LCA_{LSM}$ is analyzed by several practical experiments. The proposed $LCA_{LSM}$ compensates the collected location coordinates for the robot using the Least-Squares Method (LSM) in order to reduce the cumulated errors that occur in the Encoder/Giro sensor (E/G) and to enhance the measured tracking accuracy rates in the autonomous tracking of the robot in exhibition hall. By experiments, it was confirmed that the average error reduction rates of the $LCA_{LSM}$ are higher as 4.85% than that of the $LCA_{KF}$ in Scenario 1 (S1) and Scenario 2 (S2), respectively on the location tracking. In addition, it was also confirmed that the standard deviation in the measured errors of the $LCA_{LSM}$ are much more low and constant compared to that of the E/G sensor and the $LCA_{KF}$ in S1 and S2 respectively. Finally, we see that the suggested $LCA_{LSM}$ can execute more the stabilized location tracking than the E/G sensors and the $LCA_{KF}$ on the straight lines of S1 and S2 for the docent robot.

• Journal of agriculture & life science
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• v.53 no.4
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• pp.113-124
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• 2019

In this study, the operational characteristics of a cam-type vegetable transplanter which usually used in domestic was analyzed and operating mechanism of a transplanting device was analyzed. The main components and power path of the transplanter were analyzed. The maximum and minimum control cycles according to the moving speed and the plant spacing were analyzed. 3D modeling and simulation were performed to derive the trajectory of the bottom end of the transplanting hopper and the plant spacing at the each operating condition. The simulation results were verified by the field tests. As main findings of this study, the transplanting device has one degree of freedom (DOF) which consist of 13 links, 17 rotating joints and 1 half joint, and each part has composite structure with cam and links. By continuous and repetitive motion of the structures of transplanting device, the transplanting hopper plants the seedling in the ground with a vertical direction, and the seedling was planted stably. The power is transmitted to the driving part and transplanting device from the engine, and the maximum and minimum plant spacing of the transplanting device were about 900 mm and 350 mm, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.84-99
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• 2021

As the micro-mobility market grows, the demand for route guidance, that includes uphill information as well, is increasing. Since the climbing angle depends on the electric motor uesed, it is necessary to establish an uphill road DB according to the threshold standard. Although road alignment information is a very important element in the basic information of the roads, there is no information currently on the longitudinal slope in the road digital map. The High Definition(HD) map which is being built as a preparation for the era of autonomous vehicles has the altitude value, unlike the existing standard node link system. However, the HD map is very insufficient because it has the altitude value only for some sections of the road network. This paper, hence, intends to propose a method to generate the road longitudinal slope using currently available data. We developed a method of computing the longitudinal slope by combining the digital elevation model and the standard link system. After creating an altitude at the road link point divided by 4m based on the Seoul road network, we calculated individual slope per unit distance of the road. After designating a representative slope for each road link, we have extracted the very steep road that cannot be climbed with personal mobility and the slippery roads that cannot be used during heavy snowfall. We additionally described errors in the altitude values due to surrounding terrain and the issues related to the slope calculation method. In the future, we expect that the road longitudinal slope information will be used as basic data that can be used for various convergence analyses.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.4
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• pp.200-208
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• 2022

In this study, an automatic information collection system and geographic information construction algorithm for the transportation disadvantaged using electric mobility aids are implemented using an object recognition model. Recognizes objects that the disabled person encounters while moving, and acquires coordinate information. It provides an improved route selection map compared to the existing geographic information for the disabled. Data collection consists of a total of four layers including the HW layer. It collects image information and location information, transmits them to the server, recognizes, and extracts data necessary for geographic information generation through the process of classification. A driving experiment is conducted in an actual barrier-free zone, and during this process, it is confirmed how efficiently the algorithm for collecting actual data and generating geographic information is generated.The geographic information processing performance was confirmed to be 70.92 EA/s in the first round, 70.69 EA/s in the second round, and 70.98 EA/s in the third round, with an average of 70.86 EA/s in three experiments, and it took about 4 seconds to be reflected in the actual geographic information. From the experimental results, it was confirmed that the walking weak using electric mobility aids can drive safely using new geographic information provided faster than now.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.28-34
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• 2010

In this paper, we proposed an algorithm for utilizing visual information for non-contact predicting method of friction coefficient. Coefficient of friction is very important in driving on road and traversing over obstacle. Our algorithm is based on terrain classification for visual image. The proposed method, non-contacting approach, has advantage over other methods that extract material characteristic of road by sensors contacting road surface. This method is composed of learning group(experiment, grouping material) and predicting friction coefficient group(Bayesian classification prediction function). Every group include previous work of vision. Advantage of our algorithm before entering such terrain can be very useful for avoiding slippery areas. We make experiment on measurement of friction coefficient of terrain. This result is utilized real friction coefficient as prediction method. We show error between real friction coefficient and predicted friction coefficient for performance evaluation of our algorithm.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.532-536
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• 2009

Bypass surgery is performed for insuring continuity of a blood supply that is restricted due to obstruction of the native blood supply. Two types of surgery are commonly carried out: one is anatomic bypass and the other is extraanatomic bypass. Especially, extraanatomic bypass surgery is performed in patients who are a high risk for performing anatomical bypass surgery. The risk factors for anatomical bypass surgery are old age, infection, previous surgery and trauma. A 96-year-old patient underwent extraanatomic bypass surgery from the right femoral artery to the left femoral artery due to total occlusion of the left iliac artery, and 7 years after that operation, a pseudoaneurysm abruptly and spontaneously appeared from the bypass suture site without any predisposing factor. The lesion was revealed to be an organizing thrombus.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.817-822
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• 2014

Since the opening of the double-track railway for the Gyeongchun local electric train and the semi-high speed train ITX, floating population between Seoul and Chuncheon has rapidly increased. This is attributable to the competitiveness of the railway service in terms of punctuality and safety of operation, mass transportation and low fare. However, many passengers have expressed strong dissatisfaction and displeasure towards the interior noise and its high rate of increase, particularly in tunnel sections. In this study, the interior noise characteristics of Gyeongchun local electric train and ITX were analyzed and compared. Noise levels, frequency spectrum and sound quality indices were compared for the open land, tunnel and bridge. Finally, from the noise levels depending on the location in the vehicle compartment, the noise transmission path was determined and a basic strategy for reducing the interior noise was developed.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.50-56
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• 2010

This paper proposes a data gathering method by adapting the mobile sink to prolong the whole operation time of large WSNs. After partitioning a network into several clusters, a mobile sink visits each cluster and collects data from it. An efficient protocol improves the energy efficiency by delivering messages from the mobile sink to the cluster head as well as reduces the data gathering delay, which is the disadvantage of the mobile sink. For the scalability of sensor network, the network architecture should support the multihop transmission in the duster rather than the single hop transmission. The process for the data aggregation linked to the travelling path is proposed to improve the energy consumption of intermediate nodes. The experiment results show that the proposed model is more efficient than legacy methods in the energy consumption and the data gathering time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5215-5220
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• 2013

Recent construction in the field of 3D aversion is increasing interest in automation. This study is results about survey of the coastal landfill using automatic VRS-GPS surveying system. GPS is made with GRXI and SHC250 controller. Automatic surveying system is composed of DPS module, geomagnetism sensor, bluetooth, gimbals, IMU, etc and enables an automatic driving via entered into a route of position. The developed auto surveying system has installed the front and camera for vertical axis and can grasp situation of surveying with smartphone in real time. The comparative result between surveyed result with repetition method auto VRS-GPS surveying system observed surveyed result with VRS-RTK has shown that average error of x-axis is 0.009m, average error of y-axis, 0.010m and average error of height, 0.002m. This possibility was confirmed that field application.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.1 s.2
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• pp.85-92
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• 2003

Due to the expansion of freeway networks in Korea, drivers have more routes to choose. Traffic information on various alternative roadway sections and routes may help drivers choose the optimal route that minimizes travel time or cost. Traffic information on roadways is, therefore, invaluable in sense that individual drivers could reduce their travel time or cost by selecting optimal routes, and furthermore total travel cost of the system could be lowered. However, consensus about the price of traffic information that drivers are willing to pay is not made yet. Current price of traffic information is decided according to the price of similar information such as stock, weather and so on. To investigate the value of traffic information, a survey was conducted at freeway rest areas near Seoul Megalopolis area including Kyunggi Province. Eight hundred drivers who had travelled on freeway within a year were randomly selected. Purposive Quota Sampling was used. A price-response function, a relationship between price and sales, was obtained based on the survey, followed by sensitivity analysis