• ETRI Journal
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• v.37 no.4
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• pp.743-751
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• 2015

Cloud gaming services are heavily dependent on the efficiency of real-time video streaming technology owing to the limited bandwidths of wire or wireless networks through which consecutive frame images are delivered to gamers. Video compression algorithms typically take advantage of similarities among video frame images or in a single video frame image. This paper presents a method for computing and extracting both graphics information and an object's boundary from consecutive frame images of a game application. The method will allow video compression algorithms to determine the positions and sizes of similar image blocks, which in turn, will help achieve better video compression ratios. The proposed method can be easily implemented using function call interception, a programmable graphics pipeline, and off-screen rendering. It is implemented using the most widely used Direct3D API and applied to a well-known sample application to verify its feasibility and analyze its performance. The proposed method computes various kinds of graphics information with minimal overhead.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.42-50
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• 2018

The majority of existing falling recognition techniques provide service by recognizing only that the falling occurred. However, it is important to recognize not only the occurrence of falling but also the situation before and after the falling, as well as the location of the falling. In this paper, we design and propose the falling notification service system to recognize and provide service. This system uses the acceleration sensor of the smartphone to recognize the occurrence of a falling and the situation before and after the falling. In order to check the location of falling, GPS sensor data is used in the Google Map API to map to the map. Also, a crosswalk map converted into grid-based coordinates based on the longitude and latitude of the crosswalk is stored, and the locations before and after falling are mapped. In order to reduce the connection speed and server overload for real-time data processing, fog computing and cloud computing are designed to be distributed processing.

• Journal of KIISE
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• v.44 no.10
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• pp.1045-1061
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• 2017

This paper suggests a method to expand linkages in a Linked Open Data(LOD) cloud that is a practical consequence of a semantic web. LOD cloud, contrary to the first expectation, has not been used actively because of the lack of linkages. Current method for establishing links by applying to explicit links and attaching the links to LODs have restrictions on reflecting target LODs' changes in a timely manner and maintaining them periodically. Instead of attaching them, this paper suggests that each LOD should prepare a link policy and publish it together with the LOD. The link policy specifies target LODs, predicate pairs, and similarity degrees to decide on the establishment of links. We have implemented a system that performs in-depth searching through LODs using their link policies. We have published APIs of the system to Github. Results of the experiment on the in-depth searching system with similarity degrees of 1.0 ~ 0.8 and depth level of 4 provides searching results that include 91% ~ 98% of the trustworthy links and about 170% of triples expanded.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.45-56
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• 2017

In astronomy, the amount of data generated using wide-field optical telescope has increased exponentially. However, the fixed-size small-scale computing environment and the complexity of data analysis tools, results in difficulties to process the massive observation data collected. To resolve this problem, we propose a cloud-based automation system for the efficient processing of the enormous data gathered. The proposed system consists of a Workflow Execution Manager which manages various workflow templates and controls the execution of workflows instantiated from theses templates, and an Elastic Resource Manager that dynamically adds/deletes computing resources, according to the amount of data analysis requests. To show the effectiveness of our proposed system, we exhaustively explored a board spectrum of experiments, like elastic resources allocation, system load, etc. Finally, we describe the best practice case of DEEP-SOUTH scheduling system as an example application.

• Information Systems Review
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• v.15 no.3
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• pp.129-139
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• 2013

The Internet of Things (or IoT for short) which refers to uniquely identifiable objects and their virtual representations in an Internet-like structure is to be reality today. The amount of data on IoT is expected to increase abruptly and there are several key issues like usefulness interoperability between multiple distributes systems, services and databases. In this paper a methodology is proposed to realize a recently developed cloud service model, Contents as a Service (CaaS), which is contents delivery model referred to as 'on-demand contents'. In the proposed method, the global object identification, ePosition, comprising the structured form of two sorts of text strings with a separation symbol like # is applied to identify a specific content and registered with the content at the same server. It is easy-to-realize and effective to solve the interoperability problem systematically and logically. Some APIs for the proposed CaaS service are to be converged to provide some upgraded cloud service model such as 'CaaS supported SaaS' and 'CaaS supported PaaS'.

• Journal of the Korean Institute of Gas
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• v.13 no.3
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• pp.43-48
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• 2009

The energetic and environmental problems have been getting serious after the revolution of modern industry. Therefore, demand of gas as an eco-friendly energy source is increasing. With the demand of gas, the use of gas is also increased, so injury and loss of life by the fire have been increasing every year. Hence the influence on flame caused by Vapor Cloud Explosion in enclosure of experimental booth was calculated by using the API regulations. And the accident damage was estimated by applying the influence on the adjacent structures and people into the PROBIT model. According to the probit analysis, the spot which is 5meter away from the flame has nearly 100% of the damage probability by the first-degree burn, 27.8% of the damage probability by the second-degree burn and 14.5% of the death probability by the fire.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.292-295
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• 2018

Open API의 사용이 대중화되면서 대형 포털사이트 및 대형 소셜 네트워크 서비스에 입력한 개인정보를 바탕으로 사용자들이 원하는 서비스를 제공하는 외부 서비스(Third-party application)의 수가 계속 증가하고 있다. 이러한 외부 서비스들이 정보 제공자에게 개인정보를 요청할 때, 외부 서비스가 권한 부여를 받은 정당한 요청을 하는지 여부를 확인하기 위해 OAuth 인증 프레임워크를 사용한다. 그러나 외부 서비스가 유효한 요청을 하고 있음을 판단하기 위해 사용하는 엑세스 토큰을 탈취하면 이를 이용하여 로그인 과정을 우회할 수 있으며, 개인정보 또한 쉽게 취득 가능하다. 본 논문에서는 이러한 취약점을 해결하기 위해 OAuth 인증 프레임워크에 2차적인 인증과정을 추가하여 엑세스 토큰의 탈취를 방지하여 사용자의 계정정보와 개인정보를 보호하는 프레임워크를 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.789-791
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• 2012

세계가 주목하는 새로운 컴퓨팅 패러다임으로 클라우드 컴퓨팅 기술이 주목받고 있다. 클라우드 컴퓨팅은 다양한 사용자의 특성 및 사용 목적에 따른 서비스를 제공한다. 최근에 서비스 되고 있는 협업 클라우드 시스템은 클라우드 간 오픈 API들을 통한 상호 운영성을 바탕으로 서비스가 제공되고 있다. 하지만 클라우드 시스템은 보안과 성능, 가용성 등 개선해야할 많은 부분이 많이 남아있고, 특히 협업된 환경에서는 하나의 클라우드에 대한 공격이 다른 클라우드에 영향을 미칠 수 있기 때문에 이러한 특징을 고려한 침입탐지 및 차단을 위한 시스템이 필요하다. 본 논문은 하이퍼바이저와 유기적으로 통신하는 Hypervisor Intrusion Detection Agent(HIDA)를 이용하여 위협을 탐지, 분석하고 Warning Control Center(WCC)이용하여 협업된 클라우드 시스템에 위험을 공유함으로써 기존 시스템에 비해 보다 개선된 보안성 및 가용성을 제공하는 방법을 제안하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.25-28
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• 2012

최근 인터넷의 발달과 함께 웹을 기반으로 하는 클라이언트-서버 분산 구조의 웹서비스 시스템 구조가 점차 확산되고 있다. 게다가, 최근에는 스마트폰을 이용한 스마트폰 애플리케이션이 대중화 되면서, 웹서비스의 활용이 점차 확대되는 추세이다. REST 웹서비스는 일반적으로 기업이나 공공기관에서 자사의 정보시스템의 특정 Open API를 제공하는데 많이 활용된다. 본 연구에서는 REST 웹서비스를 조합/탑재/운용하는 시스템을 제안한다. 본 시스템을 활용하면 서비스 개발자로 하여금 서비스를 조합한 웹서비스를 일반적인 객체지향언어를 통해 개발하고 컴파일 후 업로드 하면 손쉽게 서비스를 운용할 수 있다. 본 논문에서는 REST 웹서비스 조합/탑재/운용 시스템을 제안한다. 웹서비스 조합/탑재/운용 시스템은 REST 웹서비스 개발자로 하여금 웹서비스를 손쉽게 조합하여 컴파일한 후 업로드함으로써 손쉽게 조합 REST 웹서비스를 운용할 수 있도록 한다. 이를 통해 REST 웹서비스 개발자들은 일반적인 객체지향언어를 통해 개발하고 업로드 할 수 있으며, 본 논문에서 제안하는 시스템을 통해 REST 웹서비스를 운용할 수 있다.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.245-249
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• 2021

In this paper, we present novel simulation contents for drone racing and autonomous flight of drone. With Depth camera and SLAM, we conducted mapping 3 dimensional environment through RTAB-map. The 3 dimensional map is represented by point cloud data. After that we recovered this data in Unreal Engine. This recovered raw data reflects real data that includes noise and outlier. Also we built drone racing contents like gate and obstacles for evaluating drone flight in Unreal Engine. Then we implemented both HITL and SITL by using AirSim which offers flight controller and ROS api. Finally we show autonomous flight of drone with ROS and AirSim. Drone can fly in real place and sensor property so drone experiences real flight even in the simulation world. Our simulation framework increases practicality than other common simulation that ignore real environment and sensor.