• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3086-3088
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• 1999

An ultrasonic sensor is one of most popular sensor used to navigate mobile robots within environments containing obstacles. But many navigation algorithm have studied because of the drawback of ultrasonic sensor such that poor directionality, frequent misreadings, specular reflections. Also, the most crucial drawback of this algorithm, that is VFF, VFM, EDM, PFM, WFM, GFM etc. has been that the mobile robot may become trapped in a local minimum. In this paper, we present a theoretical study of a navigation algorithm which integrals a heuristic-search local minimum (or trap) recovery method with a vector-field based method to maneuver cylindric mobile robots in unknown of unstructured environments. Also, an autonomous mobile robot uses dead-reckoning to estimate the current position and orientation of a mobile robot.

• ETRI Journal
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• v.44 no.1
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• pp.62-72
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• 2022

In this study, we propose a multi-GPU-based 8KVR stitching system that operates in real time on both local and cloud machine environments. The proposed system first obtains multiple 4 K video inputs, decodes them, and generates a stitched 8KVR video stream in real time. The generated 8KVR video stream can be downloaded and rendered omnidirectionally in player apps on smartphones, tablets, and head-mounted displays. To speed up processing, we adopt group-of-pictures-based distributed decoding/encoding and buffering with the NV12 format, along with multi-GPU-based parallel processing. Furthermore, we develop several algorithms such as equirectangular projection-based color correction, real-time CG overlay, and object motion-based seam estimation and correction, to improve the stitching quality. From experiments in both local and cloud machine environments, we confirm the feasibility of the proposed 8KVR stitching system with stitching speed of up to 83.7 fps for six-channel and 62.7 fps for eight-channel inputs. In addition, in an 8KVR live streaming test on the 5G MEC/cloud, the proposed system achieves stable performances with 8 K@30 fps in both indoor and outdoor environments, even during motion.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1876-1885
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• 2003

The artificial potential field (APF) methods provide simple and efficient motion planners for practical purposes. However, these methods have a local minimum problem, which can trap an object before reaching its goal. The local minimum problem is sometimes inevitable when an object moves in unknown environments, because the object cannot predict local minima before it detects obstacles forming the local minima. The avoidance of local minima has been an active research topic in the potential field based path planing. In this study, we propose a new concept using a virtual obstacle to escape local minima that occur in local path planning. A virtual obstacle is located around local minima to repel an object from local minima. We also propose the discrete modeling method for the modeling of arbitrary shaped objects used in this approach. This modeling method is adaptable for real-time path planning because it is reliable and provides lower complexity.

• Journal of KIISE:Software and Applications
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• v.34 no.6
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• pp.562-571
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• 2007

Various researches had been devoted in purpose of improving memory management in terms of performance, efficiency, ease of use, and safety. One of these approaches is a region-based memory management. Each allocation site selects a specific region, after that allocated objects are placed in this region. Memory is reclaimed by destroying the region, freeing all the objects allocated therein. In this paper, we propose reusing of local regions to reduce heap memory usage in memory-limited environments. The basic idea of this proposal is reusing of upper local regions where objects that are allocated to these regions are not accessed until the current method is finished. We believe our method of reusing local regions is able to overcome memory constraints in memory-limited environments.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.81-85
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• 2021

The purpose of this paper is to measure the relative efficiency of the police agencies in Korea with data collected from 2018 to 2020, using data envelopment analysis (DEA), as put forward by Charnes et al., which is used to construct a scalar measure of efficiency for all police agencies. The results of this study can be used to assist police agencies in delivering better and more efficient services to the community. The analytical results based on DEA identify potentially weak and strong police agencies on policing performance, their efficient benchmarking, and the levels of clear-ups that would make inefficient police agencies efficient. We could suggest that higher levels of the police force are associated with higher performance efficiency against crimes. But, it is a little hard to say that higher levels of the police force can keep the local police agencies efficient without explaining the contribution of other input variables to criminal arrest and prevention. On the other hand, our analysis presents that differences in operating environments and socioeconomic factors do not have a significant influence on the efficiency of local police agencies. But, it is necessary to note that we need to examine the effect of environments and socioeconomic factors on crime to create the better-policing performance.

• Journal of Korean Public Health Nursing
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• v.32 no.3
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• pp.363-375
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• 2018

Purpose: The aim of this study was to identify the influence of children's and caregivers' perceptions of local neighborhood environments on children's physical activities (PAs) and screen-based activities (SBAs) among low-income families. Methods: Secondary data analysis was performed using the data of 171 low-income children attending community child care centers and of their caregivers. Descriptive analysis, factor analysis and logistic regression analysis were employed to analyze data. Results: PAs were insufficient and SBAs were excessive in the majority of children. Children and primary caregivers had moderately negative perceptions of their local neighborhood environments. However these perceptions were not found to affect children's PAs or SBAs significantly. Conclusion: Although perceptions of local neighborhoods were not found to significantly influence children's PAs or SBAs, efforts are needed to make community child care centers and neighborhoods safer and more activity-friendly.

• Journal of Smart Tourism
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• v.3 no.3
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• pp.29-40
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• 2023

This research aims to understand the role of online reviews in the local search context by examining the effects of reviews on the representation of tourism businesses on local search platforms (LSPs). By simulating tourists' local searches for restaurants on three LSPs, namely Google, Bing, and Yelp, this study examines how different ranking results are generated across the platforms and how online reviews contribute to the differences. The findings suggest that online reviews are incorporated into LSPs as ranking factors and, thus, affect tourists' decision-making by influencing the information search results in the local search context. As one of the earliest studies on local search, this study discusses how the existing knowledge about the role of online reviews in tourists' decision-making needs to be reevaluated in mobile and more dynamic environments, and offers practical implications for tourism businesses' search engine marketing.

• Journal of Family Resource Management and Policy Review
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• v.17 no.3
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• pp.125-144
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• 2013

This aim in this study is to investigate the meaning of case management and management in general from the case manger's perspective, as well as case mangers' abilities and networks. We also propose a development direction for the establishment of a local integrated family-centered community management system. Regarding the collection of qualitative data, focus group interviews (FGIs) were conducted with 11 case managers from social welfare organizations in the city of C. The interviews consisted of open-ended questions in the following four categories: understanding of case management, case managers' abilities, case management environments, and local community networks. According to the interview analysis, a total of 16 subcategories in 9 categories and 4 domains have been identified. Due to the ambiguity regarding the concept of case management, case management was completely dependent upon individual case managers' abilities. In particular, family-centered case management was found to exist in several organizations in the same region. In terms of case management environments, the following problems have been observed: absence of related departments and staff, confusion regarding performance evaluation standards, limitations in sharing information among organizations, limitations in resource exploration and management, redundant support, and an uncomfortable relationship between the private and public sector. Horizontal exchange and cooperation among organizations are essential to establish and facilitate a local community network. After all, to establish a local family-centered community case management system, the roles of a Healthy Families Center and a Multi-cultural Family Support Center as parts of a family-centered transfer system should be fully emphasized in local society, and the performance of family-centered case management should be developed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1968-1975
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• 2011

This study was performed to propose a development guide for the periphery of local industrial park in the region of Hongseng-gun located at the mid-west of Chungnam province., which is a representative agrarian society, has been approached to a super-aged society where the region shows a continuous decrease in population, and the composition ratio of old ages is about 17.1%. Also, the region is a period of a low ebb due to the traditional agriculture based industrial structure in producing mainly simple productions. Many local governments in agrarian and fishing regions have been efforted for luring some businesses in their regions by constructing industrial complex competitively in order to solve such structural problems in such local regions. However, in some cases, these efforts cause certain destructions in the local original natural environment due to such development of industrial complex and the decrease in the settlement environment of residents. The objective of this study is to establish a local development plan for building the sustainable and comfortable settlement environments based on the settlement of the residents and the labors in such industrial complex by preventing sprawl developments in the construction of general industrial complex. This study was processed as following procedures. First, this study drew the trend in the change of the local society of H-gun through collecting literatures and analyzing it. Second, this study proposed a proper level of settlement environments required to the development of surroundings in such industrial complex based on the survey of the consciousness of residents using a statistical method. Finally, this study proposed a development guide for the surroundings based on the proposed level of settlement environments.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.38.2-38.2
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• 2019

In the history of universe, galaxies are consistently affected by surrounding medium and neighbor galaxies. These effects control galaxy evolution, making properties of galaxies diverse and dependent on environments. We investigate environments of various types of galaxies and how they affect galaxy properties, such as bar structures and galaxy sizes, etc. First, we present the observational evidence that bars can form from a cluster-cluster interaction. The evidence indicates that bars can form due to a large-scale violent phenomenon, and cluster-cluster interaction should be considered as an important channel for bar formation. Second, we discover for the first time that local early-type galaxies heavier than 1011.2 Msol show a clear environmental dependence in mass-size relation, in such a way that galaxies are as much as 20 - 40% larger in densest environments than in underdense environments. This result suggests that mergers played a significant role in the growth of massive galaxies in dense environments as expected in theory. Lastly, we investigate environments of the most massive galaxies and extremely massive quasars. By doing so, we find that massive galaxies are a much better signpost for galaxy clusters than massive quasars.