• Journal of Computing Science and Engineering
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• 제5권2호
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• pp.141-149
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• 2011

Many distributed and heterogeneous services and devices are accessible in ubiquitous computing environment, so interoperating those services and devices is one of the key tasks in implementing ubiquitous applications. We used to use script languages in integrating such interoperating components and services. However currently available most script languages are not suitable for ubiquitous environment because there are so diverse forms of interoperation targets such as service objects, web, legacy objects and programmable devices. So it is worthwhile designing a new script language well-suited to ubiquitous environment. In this paper, we propose a new script language, called Ubiscript, for the ubiquitous environment. We develop and adopt several unique language features such as remote scope, multiple contexts, web and legacy objects, remote exception handling, etc. in Ubiscript to overcome the limitations of conventional script languages. In this paper, we also describe the implementation of Ubiscript and its runtime system. A couple of ubiquitous applications were developed in Ubiscript, and the applications are tested on the runtime system. According to our experiences and evaluation, Ubiscript turned out to have a high potential in its expression power and contribution to improving ubiquitous application developers' productivity.

• 한국산학기술학회논문지
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• 제1권2호
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• pp.41-48
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• 2000

최근 산업현장의 모든 부분에서 자동화의 요구가 급격하게 증가되고 있다. 지금까지의 사격장 시스템은 정적인 환경을 중심으로 설계되어져 왔다. 그러나, 실제의 사격상황은 목표물이 동적이므로 다른 사격 환경 변화가 요구된다. 본 연구에서는 동적인 사격환경을 구현하기 위해 1개 사로에 4대의 타겟을 설치하여 사격순서를 순차 및 비순차로 구분하고 사격시간을 가변적으로 조정할 수 있게 하였다. 그리고. 자동차 및 빌딩 자동화에 많이 응용되고 있는 CAN(Controller Area Network)을 이용함으로써 효율적인 통신을 가능하게 하였다. CAN은 높은 데이터 전송률과 안정성을 제공할 수 있어 다수의 ECU(Electric Control Unit)를 상호 연결하여 분산된 실시간 제어를 효율적으로 지원할 수 있다.

• Journal of Astronomy and Space Sciences
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• 제20권4호
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• pp.403-416
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• 2003

There are common features, in both imaging surveys and image processing, between astronomical observations and remote sensing. Handling large amounts of data, in an easy and fast way, has become a common issue. Implementing pipeline software can be a solution to the problem, one which allows the processing of various kinds of data automatically. As a case study, the development of pipeline software for the EIS (European Southern Observatory Imaging Survey) is introduced. The EIS team has been conducting a sky survey to provide candidate targets to the 250 VLTs (Very Large Telescopes) observations. The survey data have been processed in a sequence of five major data corrections and reductions, i.e. preprocessing, flat fielding, photometric and astrometric corrections, source extraction, and coaddition. The processed data are eventually distributed to the users. In order to provide automatic processing of the vast volume of observed data, pipeline software has been developed. Because of the complexity of objects and different characteristic of each process, it was necessary to analyze the whole works of the EIS survey program. The overall tasks of the EIS are identified, and the scheme of the EIS pipeline software is defined. The system structure and the processes are presented, and in-depth flow charts are analyzed. During the analyses, it was revealed that handling the data flow and managing the database are important for the data processing. These analyses may also be applied to many other fields which require image processing.

• 전기전자학회논문지
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• 제18권1호
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• pp.159-164
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• 2014

본 논문에서는 하나의 태양광 모듈에 대한 전력 변환기인 마이크로 컨버터의 개발을 목표로 하고 있다. 중앙집중형 태양광발전시스템이 부분적인 음영에 의해서 성능저하가 발생하는데 반해 단일 태양광모듈의 전력변환기는 태양광모듈의 발전량을 최대화 할 수 있다. 전력 변환기는 지속적으로 각 모듈의 최대 전력 점을 추적하여 태양 광 발전 시스템의 에너지 출력을 증가시킨다. 태양광 전력 변환기의 반도체 스위치 및 외부 장치의 수를 최소화하고, 또한 동기 정류기를 사용하여, 320W급의 태양광 마이크로 컨버터를 개발하였으며, 시뮬레이션과 실험에 적용하여 효율성을 검증하였다.

• 한국멀티미디어학회논문지
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• 제18권7호
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• pp.818-826
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• 2015

With the rapid interest in Geographic Information System (GIS) contents, a large volume of valuable GIS dataset has been distributed illegally by pirates, hackers, or unauthorized users. Therefore the problem focus on how to protect the copyright of GIS vector map data for storage and transmission. But GIS vector map data is very large and current data encryption techniques often encrypt all components of data. That means we have encrypted large amount of data lead to the long encrypting time and high complexity computation. This paper presents the selective encryption scheme using hybrid transform for GIS vector map data protection to store, transmit or distribute to authorized users. In proposed scheme, polylines and polygons in vector map are targets of selective encryption. We select the significant objects in polyline/polygon layer, and then they are encrypted by the key sets generated by using Chaotic map before changing them in DWT, DFT domain. Experimental results verified the proposed algorithm effectively and error in decryption is approximately zero.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.463-474
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• 2015

Future Ground Control Stations (GCSs) for Unmanned Aerial Vehicles (UAVs) teleoperation targets better situational awareness by providing extra motion cues to stimulate the vestibular system. This paper proposes a new virtual environment for long range Unmanned Aerial Vehicle (UAV) control via Non-Line-of-Sight (NLoS) communications, which is based on motion platforms. It generates motion cues for the teleoperator for extra sensory stimulation to enhance the guidance performance. The proposed environment employs the distributed component simulation over GSM network as a simulation platform. GSM communications are utilized as a multi-hop communication network, which is similar to global satellite communications. It considers a UAV mathematical model and wind turbulence effects to simulate a realistic UAV dynamics. Moreover, the proposed virtual environment simulates a Multiple Axis Rotating Device (MARD) as Human Machine Interface (HMI) device to provide a complete delay analysis. The demonstrated measurements cover Graphical User Interface (GUI) capabilities, NLoS GSM communications delay, MARD performance, and different software workload. The proposed virtual environment succeeded to provide visual and vestibular feedbacks for teleoperators via GSM networks. The overall system performance is acceptable relative to other Line-of-Sight (LoS) systems, which promises a good potential for future long range, medium altitude UAV teleoperation researches.

• 터널과지하공간
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• 제5권2호
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• pp.114-122
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• 1995

The principle and applications of GPR(Ground Penetrating Radear) are familiar to engineering geologists and geophsicists as very attractive technique for continuous high resolution images of the subsurface. However, the main limitation of GPR is obviously related to presence of clayey or silty conductive soils, resulting in complete attenuation of radar signals. This difficulty gives hesitation for the exploration of the deeper targets for example detecting bedrock, particularly in Korean situation that most regions have conductive overburden. In order to prove usefulness of geological survey with GPR in that situation, the technique was tried to investigate depth of bedrock under thick conductive overburden and the other geolocgical informations for the constructionof foundation in the Dongbu apartment site, Kimhae. The reflection patterns on the processed GPR sections are well correlated with the geotechnical units-bedrock, alluvium, landfill unit and their internal layer-boundaries of boring data before GPR survey, except upper contact of bedrock. The isopach maps of the geotechnical units for the 3-D interpretations are made from GPR sections. The maps provided useful geological information that bedrock was distributed as plain and valley with 22~27m depth under alluvium unit (this depth is 5~8 m deeper than drill log) and sedimentary layers subsided and bended along growth fault with NNE strike/15$^{\circ}$SE dip in alluvium unit.

• Structural Engineering and Mechanics
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• 제42권3호
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• pp.291-311
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• 2012

The multi-span suspension bridge having double main cables in the vertical plane is investigated regarding endurance of live load distribution in the case of non-displaced pylon and pylon displacement. The coefficient formula of live load distribution described as the ratio of live load on the bottom cable to the top cable is obtained. Based on this formula, some function in respect of this bridge are derived and used to analyze its characteristics. This analysis targets the cable force, the cable sag and the horizontal displacement at the pylon top under live load etc. The results clarified that the performance of the live load distribution and the horizontal force of cables in the case of non-deformed pylon has a similar tendency to those in the case of deformed pylon, and the increase of pylon rigidity can increase live load distributed to the bottom cable and slightly raise the cable horizontal force under live load. However, effect on the vertical rigidity of bridge and the horizontal force increment of cables caused by live load is different in the case of non-deformed pylon and deformed pylon.

• 한국전자파학회논문지
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• 제23권7호
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• pp.822-830
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• 2012

클러터는 레이더로 수신되는 불필요한 신호로 표적 탐지에 영향을 준다. 레이더 클러터는 진폭 분포, 주파수 스펙트럼 등과 같은 특성으로 정의되며, 이러한 특성을 충분히 고려하여 클러터 모델링 및 신호 생성이 되어야 한다. 본 논문에서는 다양한 클러터의 모델링에 광범위하게 사용되는 Weibull 분포 함수를 균일 분포 함수를 이용하여 단순화한 근사적 모델링 기법에 대하여 제안한다. 제안된 Weibull 분포 함수 근사 해에 의해 발생된 데이터가 원 Weibull 확률 밀도 함수를 만족하며, 생성 시간은 약 20 % 감소함을 실험 결과를 통하여 입증한다.

• 한국IT서비스학회지
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• 제8권1호
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• pp.193-202
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• 2009

Cloud computing emerges as a new computing paradigm which targets reliable and customizable services. The term builds on decades of research in virtual machine, distributed and parallel computing, utility computing, and more recently networking, web service, and software as a service. In this paper, we provide a seamless connection migration of web services. This is useful for cloud computing environment in which many client terminals have mobility. With the wireless internet facility, those mobile users can move place to place during internet communication. Therefore, we provide solutions to the two major problems in current virtualization based migration: communication failure problems and connection re-establishment. Communication channel flushing by zero window notification helps to resolve the communication failure problems and TCP port inheritance prevents connection re-establishment errors during socket reconstruction. Thus, our web service migration facility is now able to preserve open network connections, and even for server sockets. This is a highly transparent approach, in that we did not Introduce additional messages for channel flushing and did not make any modification to the TCP protocol stack. Experimental results show that the overhead due to connection migration of web services is almost negligible when compared with time to take the conventional web service migration.