• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.215-236
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• 2017

Obtaining accurate location information is important in practical applications of wireless sensor networks (WSNs). The distance vector hop (DV-Hop) is a frequently-used range-free localization algorithm in WSNs, but it has low localization accuracy. Moreover, despite various improvements to DV-Hop-based localization algorithms, maintaining a balance between high localization accuracy and good stability and convergence is still a challenge. To overcome these shortcomings, we proposed an improved DV-Hop localization algorithm based on the bat algorithm (IBDV-Hop) for WSNs. The IBDV-Hop algorithm incorporates optimization methods that enhance the accuracy of the average hop distance and fitness function. We also introduce a nonlinear dynamic inertial weight strategy to extend the global search scope and increase the local search accuracy. Moreover, we develop an updated solutions strategy that avoids premature convergence by the IBDV-Hop algorithm. Both theoretical analysis and simulation results show that the IBDV-Hop algorithm achieves higher localization accuracy than the original DV-Hop algorithm and other improved algorithms. The IBDV-Hop algorithm also exhibits good stability, search capability and convergence, and it requires little additional time complexity and energy consumption.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.68.3-68.3
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• 2016

We analyze the dependence of environment of warped galaxies by using the local background density, Tidal Index and projected distance as measures of the environment. we use galaxies with redshift less than z=0.025 from the Sloan Digital Sky Survey (SDSS) DR7. We selected 345 edge-on galaxies using color images provided by the SDSS DR7 and checked it using isophotal maps. This sample contains 136 warped galaxies, 209 non-warped galaxies. Among warped galaxies, there are 18 strongly warped galaxies which have warp angles larger than 7.5o. We calculated the fractional distributions of galaxies as a function of environmental parameters. All of these parameters show little difference between warped galaxies and non-warped galaxies if we include weakly warped galaxies. However, there is a clear difference in the fractional distributions between the strongly warped galaxies and non-warped galaxies. The fraction of warped galaxies increases with decreasing distance to the nearest neighbor galaxy but It increases with increasing background density and Tidal Index. However, the relationships between warp angles and the three environmental parameters are not strong. The effect of Tidal Index is well distinguished in small, bright galaxies whereas the effects of the background density and the distance to the nearest neighbor galaxy are more pronounced in large, bright galaxies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.819-822
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• 2016

This paper proposes an algorithm recognizing finger using a distance graph of a detected finger's contour in a depth image. The distance graph shows angles and Euclidean distances between the center of palm and the hand contour as x and y axis respectively. We can obtain hand gestures from the graph using the fact that the graph has local maximum at the positions of finger tips. After we find the center of mass of the wrist using the fingers is thinner than the palm, we make its angle the orienting angle $0^{\circ}$. The simulation results show that the proposed algorithm can detect hand gestures well regardless of the hand direction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.554-559
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• 2009

This paper proposes a new method of weighted template matching fur machine-printed numeral recognition. The proposed weighted template matching, which emphasizes the feature of a pattern using adaptive Hamming distance on local feature areas, improves the recognition rate while template matching processes an input image as one global feature. The experiment compares confusion matrices of the template matching, error back propagation neural network classifier, and the proposed weighted template matching respectively. The result shows that the proposed method improves fairly the recognition rate of the machine-printed numerals.

• Journal of Drive and Control
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• v.21 no.1
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• pp.46-52
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• 2024

The advancement of autonomous driving technology has heightened the importance of Autonomous Mobile Robotics (AMR) within smart factories. Notably, in tasks involving the transportation of heavy objects, the consideration of weight in route optimization and path planning has become crucial. There is ongoing research on local path planning, such as Dijkstra, A^*, and RRT^*, focusing on minimizing travel time and distance within smart factory warehouses. Additionally, there are ongoing simultaneous studies on route optimization, including TSP algorithms for various path explorations and on minimizing energy consumption in mobile robotics operations. However, previous studies have often overlooked the weight of the objects being transported, emphasizing only minimal travel time or distance. Therefore, this research proposes route planning that accounts for the maximum payload capacity of mobile robotics and offers load-optimized path planning for multi-destination transportation. Considering the load, a genetic algorithm with the objectives of minimizing both travel time and distance, as well as energy consumption is employed. This approach is expected to enhance the efficiency of mobility within smart factories.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.6
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• pp.10-21
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• 2000

The Cellular Noninear Networks structure for Distance Transform(DT) and the robust optical flow detection algorithm based on the DT are proposed. For some applications of optical flows such as target tracking and camera ego-motion computation, correct optical flows at a few feature points are more useful than unreliable one at every pixel point. The proposed algorithm is for detecting the optical flows on the trajectories only of the feature points. The translation lengths and the directions of feature movements are detected on the trajectories of feature points on which Distance Transform Field is developed. The robustness caused from the use of the Distance Transform and the easiness of hardware implementation with local analog circuits are the properties of the proposed structure. To verify the performance of the proposed structure and the algorithm, simulation has been done about various images under different noisy environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1967-1972
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• 2016

This paper defines a distance graph for a hand region in a depth image and proposes an algorithm detecting finger using it. The distance graph is a graph expressing the hand contour with angles and Euclidean distances between the center of palm and the hand contour. Since the distance graph has local maximum at fingertips' position, we can detect finger points and recognize the number of them. The hand contours are always divided into 360 angles and the angles are aligned with the center of the wrist as a starting point. And then the proposed algorithm can well detect fingers without influence of the size and orientation of the hand. Under some limited recognition test conditions, the recognition test's results show that the recognition rate is 100% under 1~3 fingers and 98% under 4~5 fingers and that the failure case can also be recognized by simple conditions to be available to add.

• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.111-118
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• 2008

With the advance in mobile communication systems, the need for distributed applications running on multiple mobile devices also grows gradually. As such applications are subject to H/W failures of the mobile device or communication disruptions, compared to the traditional applications in fixed networks, it is crucial to develop any recovery mechanism suitable for them. For this, checkpointing is widely used to restart interrupted applications. In this paper, we devise an efficient checkpointing method that adopts the software agent executed at the mobile support station. The agent, called the checkpointing agent, is aimed at supporting the concept of rollback-distance (R-distance) that bounds the maximum number of roll-backed local checkpoints. By means of the R-distance, our method can prevent undesirable domino effects and heavy checkpoint overhead, while providing high flexibility in checkpoint creation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.1_2
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• pp.146-153
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• 1992

In the outpatient clinic, we have many patients who suffer from temporomandibular joint disorders. These vary from MPD syndrome to osteoarthrosis, and many cases have tender spots or areas on the temporomandibular joint region and/or masticatory muscles. Further, they frequently have masticatory muscle pain when opening the jaw. This paper presents the results of our research on the differential diagnosis for tendernesses and pain on opening the jaw in the temporomandibular joint region and the masticatory muscles by joint cavity pumping with local anesthestic. The areas of tenderness and jae-opening paw in 65 patient suffering from temporomandibular joint disorder were examined and recorded before and after anesthetizing the upper joint cavity with 2% lidocaine. Maximum interincisal distance was similarly recorded. The results were as follows : In the area surrounding the upper joint cavity including the lateral pterygoid muscle, the tenderness and jaw-opening pain vanished almost entirely after anesthesia. This was considered a direct infiltrative effect of the local anesthesia. After the anesthesia, 86% of the tendernesses on the sternocleidomastoid muscles, and 66% of those on the posterior belly of the diagstric muscles vanished, while the disappearance rates on the masseter, temporal, and medial pterygoid muscles were 50~60%. Apart from the temporomandibular region, pain on opening the jaw was found on the masseter, temporal, posterior belly of the digastric muscles, and medial pterygoid muscles before anesthesia. The disappearance rates after anesthesia were 90~100% except for the pain of the posterior belly of the digastric muscles, for which the rate was 66%. These results suggest that more than 88% of the tendernesses on the sternocleidomastoid muscle, more than 60% of the tendernesses and jaw-opening pains on the digastric muscle, and more than half of the tendernesses and almost all of the jaw-opening pains in the jaw-closing muscles are referred pains from the temporomandibular joint. The tendernesses that had no change after anesthesia were considered to be derived from spasms of the muscles proper. Generally, maximum interincisal distance increased after anesthesia. The average distance was 34mm before anesthesia, but increased to 41mm after anesthesia. In a few cases, however little or no change was found in those distances. In these cases, pathological changes were found in the joint cavities arthrographically or arthroscopically.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.331-334
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• 2012

We investigate the role of galaxy environment in the evolution of individual galaxies through the AKARI observations of the merging galaxy cluster A2255. MIR diagnostics using N3-S11 colors are adopted to select star-forming galaxies and galaxies in transition between star-forming galaxies and quiescent galaxies. We do not find particular enhancement of star formation rates as a function of galaxy environment, reflected in cluster-centric distance and local surface density of galaxies. Instead, the locations of intermediate MIR-excess galaxies (-1.2 < N3 - S11 < 0.2) show that star-forming galaxies are transformed into passive galaxies in the substructures of A2255, where the local surface density of galaxies is relatively high.