Junho Ahn

Junho Ahn


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 February 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
OSOtabek Sattarov
Otabek Sattarov
AMAzamjon Muminov
Azamjon Muminov
CLCheol-won Lee
Cheol-won Lee
HKHyun-Kyu Kang
Hyun-Kyu Kang
RORyumduck Oh
Ryumduck Oh
HJHeung Seok Jeon
Heung Seok Jeon
The net profit of investors can rapidly increase if they correctly decide to take one of these three actions: buying, selling, or holding the stocks. The right action is related to massive stock market measurements. Therefore, defining the right action requires specific knowledge from investors. The economy scientists, following their research, have suggested several strategies and indicating factors that serve to find the best option for trading in a stock market. However, several investors’ capital decreased when they tried to trade the basis of the recommendation of these strategies. That means the stock market needs more satisfactory research, which can give more guarantee of success for investors. To address this challenge, we tried to apply one of the machine learning algorithms, which is called deep reinforcement learning (DRL) on the stock market. As a result, we developed an application that observes historical price movements and takes action on real-time prices. We tested our proposal algorithm with three—Bitcoin (BTC), Litecoin (LTC), and Ethereum (ETH)—crypto coins’ historical data. The experiment on Bitcoin via DRL application shows that the investor got 14.4% net profits within one month. Similarly, tests on Litecoin and Ethereum also finished with 74% and 41% profit, respectively.

19 August 2019 in Applied Sciences
Verified
Journal Article
Open access
PDF file
AMAzamjon Muminov
Azamjon Muminov
OSOtabek Sattarov
Otabek Sattarov
CLCheol Won Lee
Cheol Won Lee
HKHyun-Kyu Kang
Hyun-Kyu Kang
MKMyeong-Cheol Ko
Myeong-Cheol Ko
HJHeung Seok Jeon
Heung Seok Jeon
Global Positioning Systems (GPS) are successfully used in many fields such as navigation, meteorology, military tasks, mapping, virtual fencing, and more. Smart collars are currently the most convenient device for determining animal location in virtual fencing systems, however; these systems are still suffering from environmental effects and propagation in direct visibility. These types of side effects may reduce the work of GPS receivers. The current article defines a method for improving animal location accuracy using a virtual fence smart collar worn around the animal’s neck by the aid of maximum probability of movement from one point to another. The proposed approach first checks the current position of the animal, and after receiving a GPS signal from satellites it calculates the distance between the two GPS signals. Secondly, the method checks the animal’s behavior for the receiving period of the two points. Finally, the approach calculates a probability of maximum animal movement for the two-point receiving period. If the animal can pass the distance in the time frame of the two signals, then the second signal is taken as the correct position; otherwise, the point is taken which the animal could pass. Real-time animal behavior is classified using Support Vector Machines (SVM). The proposed method was verified within seven days of experiments. Consequently, the proposed approach experiments were sufficiently successful. The recreated locations from our approach appeared very close to the real point. The mean average of passed distance by the marked line decreased to 16.2, 5, 0 m for running, walking, and resting conditions, respectively. On the other hand, the unfiltered geolocations of the GPS receiver, give results significantly further from the animal’s actual position such as 148.8, 182.7, 136.2 m for running, walking, and resting conditions.

1 January 2022 in Computers, Materials & Continua
Verified
Journal Article
Open access
PDF file
DKDahyeon Kim
Dahyeon Kim
CKChulsu Kim
Chulsu Kim
JAJunho Ahn
Junho Ahn
When firefighters are engaged in search and rescue missions inside a building at a risk of collapse, they have difficulty in field command and rescue because they can only simply monitor the situation inside the building utilizing old building drawings or robots. To propose an efficient solution for fast search and rescue work of firefighters, this study investigates the generation of up-to-date digital maps for disaster sites by tracking the collapse situation, and identifying the information of obstacles which are risk factors, using an artificial intelligence algorithm based on low-cost robots. Our research separates the floor by using the mask regional convolutional neural network (R-CNN) algorithm, and determines whether the passage is collapsed or not. Then, in the case of a passage that can be searched, the floor pattern of the obstacles that exist on the floor that has not collapsed is analyzed, and obstacles are searched utilizing an image processing algorithm. Here, we can detect various unknown as well as known obstacles. Furthermore, the locations of obstacles can be estimated using the pixel values up to the bounding box of an existing detected obstacle. We conduct experiments using the public datasets collected by Carnegie Mellon university (CMU) and data collected by manipulating a low-cost robot equipped with a smartphone while roaming five buildings in a campus. The collected data have various floor patterns for objectivity and obstacles that are different from one another. Based on these data, the algorithm for detecting unknown obstacles of a verified study and estimating their sizes had an accuracy of 93%, and the algorithm for estimating the distance to obstacles had an error rate of 0.133. Through this process, we tracked collapsed passages and composed up-to-date digital maps for disaster sites that include the information of obstacles that interfere with the search and rescue work.

31 July 2019 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CLCheol Won Lee
Cheol Won Lee
JLJun Dong Lee
Jun Dong Lee
JAJunho Ahn
Junho Ahn
HOHyung-Jun Oh
Hyung-Jun Oh
JPJung Kyu Park
Jung Kyu Park
HJHeung Seok Jeon
Heung Seok Jeon
The grid map, representing area information with the number of cells, is a widely used mapping scheme for mobile robots and simultaneous localization and mapping (SLAM) processes. However, the tremendous amount of cells in a grid map for a detailed map representation results in overheads for memory space and computing paths in mobile robots. Therefore, to overcome the overhead of the grid map, this study proposes a new low overhead mapping scheme which the authors call as the Rmap that represents an area with variable sizes of rectangles instead of the number of cells in the grid map. This mapping scheme also provides an exploration path for obtaining new information for the unknown area. This study evaluated the performance of the Rmap in real environments as well as in simulation environments. The experiment results show that the Rmap can reduce the overhead of a grid map. In one of our experimental environments, the Rmap represented an area with 85% less memory than the grid map. The Rmap also showed better coverage performance compared with other previous algorithms.

1 January 2023 in Intelligent Automation and Soft Computing
Verified
Journal Article
Open access
PDF file
DKDahyeon Kim
Dahyeon Kim
JMJiyoung Min
Jiyoung Min
YSYongwoo Song
Yongwoo Song
CKChulsu Kim
Chulsu Kim
JAJunho Ahn
Junho Ahn
Existing firefighting robots are focused on simple storage or fire suppression outside buildings rather than detection or recognition. Utilizing a large number of robots using expensive equipment is challenging. This study aims to increase the efficiency of search and rescue operations and the safety of firefighters by detecting and identifying the disaster site by recognizing collapsed areas, obstacles, and rescuers on-site. A fusion algorithm combining a camera and three-dimension light detection and ranging (3D LiDAR) is proposed to detect and localize the interiors of disaster sites. The algorithm detects obstacles by analyzing floor segmentation and edge patterns using a mask regional convolutional neural network (mask R-CNN) features model based on the visual data collected from a parallelly connected camera and 3D LiDAR. People as objects are detected using you only look once version 4 (YOLOv4) in the image data to localize persons requiring rescue. The point cloud data based on 3D LiDAR cluster the objects using the density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm and estimate the distance to the actual object using the center point of the clustering result. The proposed artificial intelligence (AI) algorithm was verified based on individual sensors using a sensor-mounted robot in an actual building to detect floor surfaces, atypical obstacles, and persons requiring rescue. Accordingly, the fused AI algorithm was comparatively verified.

31 October 2020 in KSII Transactions on Internet and Information Systems
Verified
Journal Article
Closed access
JJJuho Jung
Juho Jung
MPManbok Park
Manbok Park
KCKuk Cho
Kuk Cho
Cheol MunCheol Mun
Cheol Mun
JAJunho Ahn
Junho Ahn
Due to the significant increase in the use of autonomous car technology, it is essential to integrate this technology with high-precision digital map data containing more precise and accurate roadway information, as compared to existing conventional map resources, to ensure the safety of self-driving operations. While existing map technologies may assist vehicles in identifying their locations via Global Positioning System, it is however difficult to update the environmental changes of roadways in these maps. Roadway vision algorithms can be useful for building autonomous vehicles that can avoid accidents and detect real-time location changes. We incorporate a hybrid architectural design that combines unsupervised classification of vision data with supervised joint fusion classification to achieve a better noise-resistant algorithm. We identify, via a deep learning approach, an intelligent hybrid fusion algorithm for fusing multimodal vision feature data for roadway classifications and characterize its improvement in accuracy over unsupervised identifications using image processing and supervised vision classifiers. We analyzed over 93,000 vision frame data collected from a test vehicle in real roadways. The performance indicators of the proposed hybrid fusion algorithm are successfully evaluated for the generation of roadway digital maps for autonomous vehicles, with a recall of 0.94, precision of 0.96, and accuracy of 0.92.