• Nuclear Engineering and Technology
• /
• 제53권10호
• /
• pp.3449-3459
• /
• 2021

With the increasing availability of high-performance computing (HPC) platforms, uncertainty quantification (UQ) and sensitivity analyses (SA) can be efficiently leveraged to optimize design parameters of complex engineering problems using modeling and simulation tools. The workflow involved in such studies heavily relies on HPC resources and hence requires pre-processing and post-processing capabilities of large amounts of data along with remote submission capabilities. The NEAMS Workbench addresses all aspects of the workflows involved in these studies by relying on a user-friendly graphical user interface and a python application program interface. This paper highlights the NEAMS Workbench capabilities by presenting a semiautomated coupling scheme between Dakota and any given package integrated with the NEAMS Workbench, yielding a simplified workflow for users. This new capability is demonstrated by running a SA of a turbulent flow in a pipe using the open-source Nek5000 CFD code. A total of 54 jobs were run on a HPC platform using the remote capabilities of the NEAMS Workbench. The results demonstrate that the semiautomated coupling scheme involving Dakota can be efficiently used for UQ and SA while keeping scripting tasks to a minimum for users. All input and output files used in this work are available in https://code.ornl.gov/neams-workbench/dakota-nek5000-study.

• 한국기계가공학회지
• /
• 제18권5호
• /
• pp.1-8
• /
• 2019

Breath analysis using a portable device is better than the classical breath analysis system in terms of installation and operation. There is an increasing need to develop cost-effective equipment for testing gas sensors from the viewpoint of functionalities that can be applied applicable to portable devices. In the present study, an economical gas chamber for in-situ gas measurement is implemented with a single gas chamber without using expensive gas storage and control equipment; the gas response characteristics are analyzed using the above-described chamber. The main features of the implemented gas chamber are simple injection procedure, improved gas diffusion, easy measurement and cleaning, support for low-power mode measurement function for portable devices, and open source platform. Moreover, an analysis of gas response characteristics based on changes in sensor voltage show that the sensitivity and 90% response time are affected by the sensor voltage. Furthermore, the sensitivity graph has an inflection point in a specific range. The gas sensor applied in this study showed fast response speed and high sensitivity for sensor voltages of 3.0-3.5 V, regardless of the concentration of acetone gas, the target gas used in this study.

• 로봇학회논문지
• /
• 제14권2호
• /
• pp.122-130
• /
• 2019

Collecting a rich but meaningful training data plays a key role in machine learning and deep learning researches for a self-driving vehicle. This paper introduces a detailed overview of existing open-source simulators which could be used for training self-driving vehicles. After reviewing the simulators, we propose a new effective approach to make a synthetic autonomous vehicle simulation platform suitable for learning and training artificial intelligence algorithms. Specially, we develop a synthetic simulator with various realistic situations and weather conditions which make the autonomous shuttle to learn more realistic situations and handle some unexpected events. The virtual environment is the mimics of the activity of a genuine shuttle vehicle on a physical world. Instead of doing the whole experiment of training in the real physical world, scenarios in 3D virtual worlds are made to calculate the parameters and training the model. From the simulator, the user can obtain data for the various situation and utilize it for the training purpose. Flexible options are available to choose sensors, monitor the output and implement any autonomous driving algorithm. Finally, we verify the effectiveness of the developed simulator by implementing an end-to-end CNN algorithm for training a self-driving shuttle.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제18권8호
• /
• pp.2316-2332
• /
• 2024

In this paper, we introduce a web-based system that leverages the capabilities of the ρ(rho)-algorithm, which is a Structure Information Control Net (SICN)-oriented process mining algorithm, with open-source platforms, including Django, Graphviz, and Cytoscape, to facilitate the rediscovery and visualization of business process models. Our approach involves discovering SICN-oriented process models from process instances from the IEEE XESformatted process enactment event logs dataset. This discovering process is facilitated by the ρ-algorithm, and visualization output is transformed into either a JSON or DOT formatted file, catering to the compatibility requirements of Cytoscape or Graphviz, respectively. The proposed system utilizes the robust Django platform, which enables the creation of a userfriendly web interface. This interface offers a clear, concise, modern, and interactive visualization of the rediscovered business processes, fostering an intuitive exploration experience. The experiment conducted on our proposed web-based process discovery system demonstrates its ability and efficiency showing that the system is a valuable tool for discovering business process models from process event logs. Its development not only contributes to the advancement of process mining but also serves as an educational resource. Readers, students, and practitioners interested in process mining can leverage this system as a completely free process miner to gain hands-on experience in rediscovering and visualizing process models from event logs.

• Computers and Concrete
• /
• 제34권3호
• /
• pp.355-365
• /
• 2024

TECSolverApp is an application that calculates the total equivalent seismic load (base shear) and shows the design spectra in accordance with the Turkish Earthquake Code (TEC). TECSolverApp software can present the spectral acceleration-period graph and the base shear (in terms of unit building weight) in MATLAB and .NET Core frameworks according to TEC 2007 and TEC 2018. In the software, three different building period evaluation options were provided, as entering the period directly, empirical calculation, and using the period calculation formula. In different period calculation scenarios, particular design input parameters such as site-specific spectral acceleration coefficients, local soil class, building importance coefficient, and structural system behavior coefficient are expected. TECSolverApp was produced in two different programming languages and published in MATLAB App Designer and ASP.NET Core MVC environments. To be shared in MATLAB App Designer, it was aimed at availability through the program and distributability as a desktop application. By deploying in ASP.NET Core MVC, open-source cross-platform coding and web-based accessibility were targeted. One of the strongest aspects of TECSolverApp is its developability thanks to software architecture. In this respect, it can be foreseen that other international seismic codes can be added to the calculations in the future.

• 한국태양에너지학회 논문집
• /
• 제34권4호
• /
• pp.17-22
• /
• 2014

The design of a fuel cells stack is important to get optimal output power. This study focuses on the evaluation of fuel cell system for unmaned aerial vehicles (UAVs). Low temperature proton exchange membrane (LTPEM) fuel cells are the most promising energy source for the robot applications because of their unique advantages such as high energy density, cold startup, and quick response during operation. In this paper, a 600 W open cathode LTPEM fuel cell was tested to evaluate the performance and to determine optimal operating conditions. The open cathode design reduces the overall size of the system to meet the requirement for robotic application. The cruise power requirement of 600 W was supported entirely by the fuel cell while the additional power requirements during takeoff was extended using a battery. A peak of power of 900 W is possible for 10 mins with a lithium polymer (LiPo) battery. The system was evaluated under various load cycles as well as start-stop cycles. The system response from no load to full load meets the robot platform requirement. The total weigh of the stack was 2 kg, while the overall system, including the fuel processing system and battery, was 4 kg.

• 한국항행학회논문지
• /
• 제15권4호
• /
• pp.632-639
• /
• 2011

최근 클라우드 컴퓨팅 시대에 접어들면서 분산 컴퓨팅 환경에서의 분산된 자원의 효율적인 검색이 중요하다. P2P(Peer-to-Peer) 네트워크에서 분산된 정보를 검색하기 위해서는 수많은 Peer를 순회하며 정보를 검색하기 때문에 네트워크의 규모 및 네트워크 상태에 따른 시스템의 부하와 많은 검색 시간을 소요하게 된다. JXTA(Juxtapose)는 P2P를 실현하기 위하여 셀 폰, PDA, 서버에 연결되어 있는 PC 등 어떤 다양한 디바이스도 커뮤니케이션 및 상호 협력을 위해 네트워크에 연결될 수 있도록 해 주는 P2P 프로토콜의 오픈 셋이라 할 수 있다. 본 논문에서는 P2P 오버레이 네트워크에서 JXTA를 이용한 효과적인 Peer 탐색 알고리즘을 제안한다. 기존 JXTA의 Peer 탐색 알고리즘은 DHT(Distributed Hashing Tables) 기반의 A Loosely-Consistent DHT 방식을 활용한다. 제안한 Peer 탐색 알고리즘은 WALK_LOOKUP 메시지의 수를 줄임으로써 시스템의 부하를 줄였고, 기존 JXTA-Sim의 Peer 탐색 성공률과 동등한 성능을 보임으로써, 이를 적용하여 향 후 다른 네트워크상에서도 메시지의 수를 줄일 수 있는 최적화 모델을 찾아야 할 것이다.

• Earthquakes and Structures
• /
• 제17권4호
• /
• pp.373-385
• /
• 2019

In this article, different frequently adopted modeling aspects of linear and nonlinear dynamic soil-structure interaction (SSI) are studied on a pile-supported integral abutment bridge structure using the open-source platform OpenSees (McKenna et al. 2000, Mazzoni et al. 2007, McKenna and Fenves 2008) for a 2D domain. Analyzed approaches are as follows: (i) free field input at the base of fixed base bridge; (ii) SSI input at the base of fixed base bridge; (iii) SSI model with two dimensional quadrilateral soil elements interacting with bridge and incident input motion propagating upwards at model bottom boundary (with and without considering the effect of abutment backfill response); (iv) simplified SSI model by idealizing the interaction between structural and soil elements through nonlinear springs (with and without considering the effect of abutment backfill response). Salient conclusions of this paper include: (i) free-field motions may differ significantly from those computed at the base of the bridge foundations, thus put a significant bias on the inertial component of SSI; (ii) conventional modeling of SSI through series of soil springs and dashpot system seems to stay on the safer side under dynamic conditions when one considers the seismic actions on the structure by considering a fully coupled SSI model; (iii) consideration of abutment-backfill in the SSI model positively affects the general response of the bridge, as a result of large passive resistance that may develop behind the abutments.

• 한국인터넷방송통신학회논문지
• /
• 제13권3호
• /
• pp.151-156
• /
• 2013

안드로이드는 구글과 오픈 핸드셋 얼라이언스가 만들어낸 모바일폰용 오픈 소스 소프트웨어 툴킷이다. 안드로이드는 몇 년 내로 수백만 개의 핸드폰 및 그 밖의 모바일 장치에 사용될 것이며, 응용프로그램 개발자들의 주요 플랫폼이 될 것이다. 본 논문에서는 구글의 안드로이드 플랫폼을 기반으로 통합로그인 애플리케이션을 개발을 한다. 개발된 안드로이드 기반 모바일 통합 로그인 애플리케이션 컨텐츠의 특징은 다음과 같다. 첫째, 모바일 기반의 웹 브라우저(웹브라우저 스타일의 응용 애플리케이션)로서 일반적인 웹브라우저보다 편리한 로그인 기능, 보안기능과 데이터 전송량을 줄여서 보다 빠른 화면 기능을 가지고 있다. 둘째, ID 및 Password 관리에 유용하며, 여러 ID의 정보 등을 쉽게 관리 할수 있다. 개발된 애플리케이션의 성능평가 결과는 다음과 같다. 여러 포털사이트를 동시 로그인하는 기능과 계속적으로 로그인이 유지되는 기능을 가지고 있음을 보였다. 현재, 하나의 ID 안에 여러 계정의 ID를 삽입하는 기술과 한 화면에서 모든 정보를 확인할 수 있는 기능을 개발 중에 있다.

• 대한원격탐사학회지
• /
• 제33권6_3호
• /
• pp.1215-1221
• /
• 2017

SNAP(SeNtinel's Application Platform)은 유럽우주국이 개발한 공개 소프트웨어로서, SAR(Synthetic Aperture Radar)와 광학위성을 포함한 Sentinel 위성 시리즈에서 얻은 자료를 처리하는 여러개의 Toolbox로 이루어져 있다. 이 중 S1TBX(Sentinel-1 ToolBoX)는 주로 Sentinel-1A/B 영상과 간섭기법을 처리하기 위한 프로그램으로, Graph Builder와 같은 흐름도 방식의 자료처리 기법을 제공하고 DEM(Digital Elevation Model) 자동다운로드 및 모자이크 등을 포함한 편리한 기능을 탑재하고 있다. 프로그램 업데이트가 매우 활발하여, 컴퓨터 메모리가 충분하다면 InSAR(Interferometric SAR)와 DInSAR(Differential InSAR)의 수행이 원활해 최근 전세계적으로 널리 이용되고 있다. S1TBX에는 또한 기존의 타 SAR 위성 자료 처리기능을 포함하고 있으며, 최근 버전 5 이후에는 KOMPSAT-5의 처리 기능도 추가되었다. 이 연구에서는 SNAP의 S1TBX를 이용하여 KOMPSAT-5 SAR 영상의 간섭기법을 처리한 예를 보여주고 있다. 몽골 Tavan Tolgoi 노천탄광에서는 2015년도에 KOMPSAT-5로 얻어진 DEM과 2000년에 얻어진 SRTM 1sec DEM의 차이를 분석한 결과, 15년 동안 최대 130미터 깊이를 채굴하였고 쌓아놓은 광석의 높이가 70미터를 넘는 것을 확인하였다. 남극 장보고기지 인근 빙하지역에서는 타 프로그램에서는 조석과 지형 InSAR 신호가 관찰 되었으나, 궤도오차 및 DEM 오차로 SNAP으로는 처리가 불가했다. 또한 이라크 사막지역에서 여러 장의 DInSAR 영상이 만들어졌으나 시스템 오차로 보이는 줄무늬가 coherence 영상에 다수 발견되었다. StaMPS 적용을 위한 Stack은 궤도 오차 혹은 프로그램 버그로 인하여 불가했다. 최근 SNAP의 사용자가 급증하고 있고 업그레이드가 매우 빠르기 때문에 조만간 해결될 것으로 기대한다.