• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.425-431
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• 2012

Utilizing the three-dimensional Snyder-Mitchell model with a PT-symmetric potential, we study the influence of PT symmetry on beam propagation in strongly nonlocal nonlinear media. The complex Coulomb potential is used as the PT-symmetric potential. A localized spatiotemporal accessible soliton solution of the model is obtained. Specific values of the modulation depth for different soliton parameters are discussed. Our results reveal that in these media the localized solitons can exist in various shapes, such as single-layer and multi-layer disk-shaped structures, as well as vortex-ring and necklace patterns.

• 한국측량학회지
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• 제32권6호
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• pp.637-650
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• 2014

Geospatial research on emergency response in multi-level micro-spatial environments (e.g., multi-story buildings) that aims at understanding and analyzing human movements at the micro level has increased considerably since 9/11. Past research has shown that reducing the time rescuers needed to reach a disaster site within a building (e.g., a particular room) can have a significant impact on evacuation and rescue outcomes in this kind of disaster situations. With the purpose developing emergency response systems that are capable of using complex real-time geospatial information to generate fast-changing scenarios, this study develops a Spatiotemporal Optimal Route Algorithm (SORA) for guiding rescuers to move quickly from various entrances of a building to the disaster site (room) within the building. It identifies the optimal route and building evacuation bottlenecks within the network in real-time emergency situations. It is integrated with a Ubiquitous Sensor Network (USN) based tracking system in order to monitor dynamic geospatial entities, including the dynamic capacities and flow rates of hallways per time period. Because of the limited scope of this study, the simulated data were used to implement the SORA and evaluate its effectiveness for performing 3D topological analysis. The study shows that capabilities to take into account detailed dynamic geospatial data about emergency situations, including changes in evacuation status over time, are essential for emergency response systems.

• Journal of the Korean Data and Information Science Society
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• 제15권3호
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• pp.663-675
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• 2004

A battlefield simulation is the evaluation and analysis of the battlefield area, based on the data for terrain, climate, unit's maneuver and tactics basically required in battlefield simulation. Because it is difficult for the military authorities to collect all of the information perfectly for the reason of communication technology, jamming, and tactics, the military authorities need the future moving status for the target units by using acquired moving information. Therefore, we propose a moving object management system that concurrently provides domain reasoning function for the battlefield simulation. In order to implement the proposed system, we show the data modeling of the moving object for the battlefield simulation, and propose an inference engine using domain rule base and spatiotemporal operation. Also, we analyze the query response rate by inference function to verify domain reasoning of the implemented system.

• International Journal of Computer Science & Network Security
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• 제23권5호
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• pp.212-220
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• 2023

Ontologies are knowledge containers in which information about a specified domain can be shared and reused. An event happens within a specific time and place and in which some actors engage and show specific action features. The fact is that several ontology models are based on events called Event-Based Models, where the event is an individual entity or concept connected with other entities to describe the underlying ontology because the event can be composed of spatiotemporal extents. However, current event-based ontologies are inadequate to bridge the gap between spatiotemporal extents and participants to describe a specific domain event. This paper reviews, describes, and compares the existing event-based ontologies. The paper compares and contrasts various ways of representing the events and how they have been modelled, constructed, and integrated with the ontologies. The primary criterion for comparison is based on the events' ability to represent spatial and temporal extent and the participants in the event.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7737-7742
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• 2015

Background: Cancer is one of the common causes of disability and mortality in the world. The present study aimed to define the spatiotemporal distribution of gastrointestinal tract cancers using a geographic information system (GIS) over the time period of 2007-2012 in Kermanshah-Iran. Materials and Methods: The method of studying was descriptive-analytical as well as comparative with gastrointestinal tract cancer patients based in the City of Kermanshah over the time period covered. For data analysis, the GIS and SPSS 16.0 were applied. Results: According to the pathological reports within the space of 5 years, 283 cases of gastrointestinal tract cancer (157 in males, 156 in females) were reported. The performed tests in terms of spatial distribution in the environment of GIS indicated that the disease demonstrated a clustered pattern in the City of Kermanshah. More to the point, some loci of this disease have emerged in the City of Kermanshah that in the first level, 6 neighborhoods with 29-59 cases of this disease per square kilometer and in the second level, 15-29 cases. Conclusions: Gastrointestinal tract cancer demonstrated an ascending trend within the space of 5 years of research and the spatiotemporal distribution of cancer featured a concentrated and clustered pattern in the City of Kermanshah.

• 한국컴퓨터정보학회논문지
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• 제29권9호
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• pp.9-23
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• 2024

본 연구에서는 3차원 보행 데이터 기반 체질량지수(Body Mass Index, BMI) 추정 기술의 분류 정확도를 향상시킬 수 있는 방법을 제안한다. BMI 추정 기술에 관해 기존 연구에서는 BMI 분류 정확도가 약 60%에 불과했다. 이에 본 연구에서는 먼저 BMI 분류 정확도가 낮았던 원인을 규명한다. 본 연구의 분석 결과에 따르면, 그 원인은 보행 데이터 세트의 클래스 불균형(Class Imbalance) 문제를 해결하기 위해 언더샘플링(Undersampling) 기법을 사용한 것에 있었다. 이에 본 연구에서는 언더샘플링 기법 대신 오버샘플링(Oversampling) 기법을 적용해 클래스 불균형 문제를 해결하는 것을 제안한다. 또한, 보행 데이터 기반 BMI 추정 기술에서 인체 측정학(Anthropometric) 특징과 시공간적(Spatiotemporal) 특징의 유용성을 재입증한다. 기존 연구에서는 언더샘플링 기법이 적용된 상태에서 인체 측정학 특징과 시공간적 특징의 유용성이 평가됐고, 두 특징을 함께 사용하면 단독으로 사용했을 때보다 BMI 추정 성능이 낮아진다고 보고됐다. 하지만 본 연구 결과에 따르면, 두 특징을 함께 사용하고 오버샘플링 기법을 적용했을 때 BMI 추정 문제에서 92.92%의 정확도로 SOTA(State-Of-The-Art) 성능을 달성하는 것을 보인다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2001년도 추계공동학술대회 논문자료집 정보화 젼략 패러다임의 변화에 대한 보기술의 대응
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• pp.207-208
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• 2001

• 대한토목학회논문집
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• 제42권4호
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• pp.519-526
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• 2022

자율주행 자동차는 기본적으로 차량과 도로에 설치된 센서를 활용해 수집된 도로·교통 정보를 통해 자율주행 기능을 수행한다. 그러나 이러한 기술과 정보만으로는 완전한 자율주행을 구현하는 것에 한계가 있음을 인정하고 있다. 최근에는 센서 기반 자율주행 기술의 한계를 극복하기 위해 다양한 방면에서 노력을 하고 있으며, 동적지도정보(local dynamic map: LDM)라 불리는 보다 구체적이고 정확한 도로 및 교통정보를 활용하는 노력도 진행 중이다. 그러나 LDM 관련 데이터 표준 및 데이터 세부항목 등이 아직 충분히 검증되지 않았으며, 자율주행 중 LDM의 시공간적 제공 범위에 대한 연구는 극히 제한적이다. 이러한 배경 하에, 본 연구의 목적은 기존 LDM 관련 연구 사례를 통해 기존 연구의 한계를 도출하고, 나아가 LDM 기반 도로·교통정보의 시공간적 활성화 구간 산정 프레임워크을 제시하는 것이다.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 국내 LBS 기술개발 및 표준화 동향세미나
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• pp.81-88
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• 2004

GIS (geographic information system) applications increasingly require the representation of geospatial objects with fuzzy extent and querying of time-varying information. In this paper, we Introduce a FSTDB (fuzzy spatiotemporal database) to represent and manage states and events causing changes of dynamic fuzzy objects using fuzzy set theory. We also propose the algorithms for the operators to be included in a GIS to make it able to answer queries depending on fuzzy predicates during a time interval and a method to identify the development process of objects during a certain period based on the designed database. They can be used in application areas handling time-varying geospatial data, including global change (as in climate or land cover change) and social (demographic, health, ect.) application.

• ETRI Journal
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• 제31권2호
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• pp.151-161
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• 2009

In this paper, we propose an adaptive multiview video coding scheme based on spatiotemporal correlation analyses using hierarchical B picture (AMVC-HBP) for the integrative encoding performances, including high compression efficiency, low complexity, fast random access, and view scalability, by integrating multiple prediction structures. We also propose an in-coding mode-switching algorithm that enables AMVC-HBP to adaptively select a better prediction structure in the encoding process without any additional complexity. Experimental results show that AMVC-HBP outperforms the previous multiview video coding scheme based on H.264/MPEG-4 AVC using the hierarchical B picture (MVC-HBP) on low complexity for 21.5%, on fast random access for about 20%, and on view scalability for 11% to 15% on average. In addition, distinct coding gain can be achieved by AMVC-HBP for dense and fast-moving sequences compared with MVC-HBP.