• Title/Summary/Keyword: software architecture

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Numerical simulation of fish nets in currents using a Morison force model

  • Cifuentes, Cristian;Kim, M.H.
    • Ocean Systems Engineering
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    • v.7 no.2
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    • pp.143-155
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    • 2017
  • For complex flexible structures such as nets, the determination of drag forces and its deformation is a challenging task. The accurate prediction of loads on cages is one of the key steps in designing fish farm facilities. The basic physics with a simple cage, can be addressed by the use of experimental studies. However, to design more complex cage system for various environmental conditions, a reliable numerical simulation tool is essential. In this work, the current load on a cage is calculated using a Morison-force model applied at instantaneous positions of equivalent-net modeling. Variations of solidity ratio ($S_n$) of the net and current speed are considered. An equivalent array of cylinders is built to represent the physical netting. Based on the systematic comparisons between the published experimental data for Raschel nets and the current numerical simulations, carried out using the commercial software OrcaFlex, a new formulation for $C_d$ values, used in the equivalent-net model, is presented. The similar approach can also be applied to other netting materials following the same procedure. In case of high solidity ratio and current speed, the hybrid model defines $C_d$ as a function of Re (Reynolds number) and $S_n$ to better represent the corresponding weak diffraction effects. Otherwise, the conventional $C_d$ values depending only on Re can be used with including shielding effects for downstream elements. This new methodology significantly improves the agreement between numerical and experimental data.

Simulation for the Prediction of Indicated Performances of a Gasoline Engine Using GT-POWER (가솔린 기관의 도시성능 예측을 위한 시뮬레이션: GT-POWER를 이용한 경우)

  • Choi, Won-Jeong;Ryu, Soon-Pil;Yoon, Keon-Sik
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.4
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    • pp.368-373
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    • 2015
  • As a preliminary study for the development of the gas fueled marine engine, prediction of indicated performances was carried out for a spark-ignition engine using commercial software, GT-POWER. The optimized models through a previous study were applied for the simulation of the intake and exhaust systems in a SI engine. The Spark-Ignition Wiebe model was used to calculate the burn rate in the cylinders and the modified Woschni model was used to calculate the heat transfer to the walls. The predicted performances, such as air delivery, cylinder pressures and indicated mean effective pressures under a range of operating conditions showed good agreement with the experiments.

A study for roll damping performance of a platform supply vessel with or without bilge keel using CFD (전산유체역학을 이용한 해양작업지원선의 빌지킬 유무에 따른 횡동요 성능에 관한 연구)

  • Seok, Jun;Kim, Sung-Yong;Yang, Young-Jun;Jin, Song-Han;Park, Jong-Chun
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.9
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    • pp.791-798
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    • 2016
  • In this study, numerical simulations on the effects of bilge keel on roll motion were conducted. The numerical simulations were performed on a 110 m class PSV using the commercial viscous flow analysis software Star-CCM+. Before conducting the study on the 110 m class PSV, an additional simulation of DTMB 5512 was performed and compared with the experimental results to validate the feasibility of the numerical simulation. In the simulation on PSV, a nondimensional damping coefficient was calculated using a free roll decay simulation, and the response amplitude operator (RAO) for the roll motion was calculated with a nondimensional damping coefficient at two conditions (with/without bilge keel).

ACCESS CONTROL MODEL FOR DATA STORED ON CLOUD COMPUTING

  • Mateen, Ahmed;Zhu, Qingsheng;Afsar, Salman;Rehan, Akmal;Mumtaz, Imran;Ahmad, Wasi
    • International Journal of Advanced Culture Technology
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    • v.7 no.4
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    • pp.208-221
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    • 2019
  • The inference for this research was concentrated on client's data protection in cloud computing i.e. data storages protection problems and how to limit unauthenticated access to info by developing access control model then accessible preparations were introduce after that an access control model was recommend. Cloud computing might refer as technology base on internet, having share, adaptable authority that might be utilized as organization by clients. Compositely cloud computing is software's and hardware's are conveying by internet as a service. It is a remarkable technology get well known because of minimal efforts, adaptability and versatility according to client's necessity. Regardless its prevalence large administration, propositions are reluctant to proceed onward cloud computing because of protection problems, particularly client's info protection. Management have communicated worries overs info protection as their classified and delicate info should be put away by specialist management at any areas all around. Several access models were accessible, yet those models do not satisfy the protection obligations as per services producers and cloud is always under assaults of hackers and data integrity, accessibility and protection were traded off. This research presented a model keep in aspect the requirement of services producers that upgrading the info protection in items of integrity, accessibility and security. The developed model helped the reluctant clients to effectively choosing to move on cloud while considerate the uncertainty related with cloud computing.

Pub/Sub-based Sensor virtualization framework for Cloud environment

  • Ullah, Mohammad Hasmat;Park, Sung-Soon;Nob, Jaechun;Kim, Gyeong Hun
    • International journal of advanced smart convergence
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    • v.4 no.2
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    • pp.109-119
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    • 2015
  • The interaction between wireless sensors such as Internet of Things (IoT) and Cloud is a new paradigm of communication virtualization to overcome resource and efficiency restriction. Cloud computing provides unlimited platform, resources, services and also covers almost every area of computing. On the other hand, Wireless Sensor Networks (WSN) has gained attention for their potential supports and attractive solutions such as IoT, environment monitoring, healthcare, military, critical infrastructure monitoring, home and industrial automation, transportation, business, etc. Besides, our virtual groups and social networks are in main role of information sharing. However, this sensor network lacks resource, storage capacity and computational power along with extensibility, fault-tolerance, reliability and openness. These data are not available to community groups or cloud environment for general purpose research or utilization yet. If we reduce the gap between real and virtual world by adding this WSN driven data to cloud environment and virtual communities, then it can gain a remarkable attention from all over, along with giving us the benefit in various sectors. We have proposed a Pub/Sub-based sensor virtualization framework Cloud environment. This integration provides resource, service, and storage with sensor driven data to the community. We have virtualized physical sensors as virtual sensors on cloud computing, while this middleware and virtual sensors are provisioned automatically to end users whenever they required. Our architecture provides service to end users without being concerned about its implementation details. Furthermore, we have proposed an efficient content-based event matching algorithm to analyze subscriptions and to publish proper contents in a cost-effective manner. We have evaluated our algorithm which shows better performance while comparing to that of previously proposed algorithms.

Data Collection Methods to Standardize Protocols of Safety Supervision System (안전관제시스템 프로토콜 표준화를 위한 데이터 수집 방법)

  • Shin, Kwang-Ho;Um, Tae-Hwa;Lim, Dam-Sub;Ahn, Jin
    • Journal of the Korean Society for Railway
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    • v.19 no.2
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    • pp.159-169
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    • 2016
  • The current railway control system in Korea is comprised of signaling, electric rail power, communication, and maintenance systems that are independent of each other. Further, these systems have different mediums and protocols for transmitting the field equipment data to the central control system. The Safety Supervision System has as its purpose the collecting of safety-related data from each system to predict and prevent accidents, this system utilizes standard protocol. Safety-related data need to be collected from field data transmission devices of the existing control system, the data should be collected without affecting the communication of the existing system. In this study, sniffing skill, which is typically used for network traffic monitoring or security, is used to collect data. The problems arising from the use of sniffing devices are noted, and the Packet Conversion Node is proposed as a solution to the problems. Further, functional and performance testing were completed for the prototype, and the software architecture and packet conversion process were verified.

Decentralized TDM-PON MAC Protocol Based on Power Detection (파워검출 기반의 분산형 TDM-PON MAC 프로토콜)

  • Lee, Sung-Kuen;Kim, Eal-Lae;Lee, Yong-Won;Lee, Sang-Rok;Jung, Dae-Kwang;Hwang, Seong-Taek;Oh, Yun-Je;Park, Jin-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2B
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    • pp.83-89
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    • 2007
  • In this paper, we have proposed the power detection (PD)-based TDM-PON architecture, which is implemented with a hardware-based decentralized DBA (Dynamic Bandwidth Allocation) algorithm among ONUs, without OLT's intervention. Of particular importance in the proposed approach is that the hardware-based power detection scheme is used to manage the distributed MAC algorithm without any complex, time-consuming and costly software-processing elements for DBA in ONUs and OLT. We evaluate the performance of average packet end-to-end delay in a statistical analysis and numerical analysis. In addition, through simulations with various traffic models, we verified the superior performance of the proposed approach by comparing with the results of other E-PONs.

Virtual Ground Based Augmentation System

  • Core, Giuseppe Del;Gaglione, Salvatore;Vultaggio, Mario;Pacifico, Armando
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.33-37
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    • 2006
  • Since 1993, the civil aviation community through RTCA (Radio Technical Commission for Aeronautics) and the ICAO (International Civil Air Navigation Organization) have been working on the definition of GNSS augmentation systems that will provide improved levels of accuracy and integrity. These augmentation systems have been classified into three distinct groups: Aircraft Based Augmentation Systems (ABAS), Space Based Augmentation Systems (SBAS) and Ground Based Augmentation Systems (GBAS). The last one is an implemented system to support Air Navigation in CAT-I approaching operation. It consists of three primary subsystems: the GNSS Satellite subsystem that produces the ranging signals and navigation messages; the GBAS ground subsystem, which uses two or more GNSS receivers. It collects pseudo ranges for all GNSS satellites in view and computes and broadcasts differential corrections and integrity-related information; the Aircraft subsystem. Within the area of coverage of the ground station, aircraft subsystems may use the broadcast corrections to compute their own measurements in line with the differential principle. After selection of the desired FAS for the landing runway, the differentially corrected position is used to generate navigation guidance signals. Those are lateral and vertical deviations as well as distance to the threshold crossing point of the selected FAS and integrity flags. The Department of Applied Science in Naples has create for its study a virtual GBAS Ground station. Starting from three GPS double frequency receivers, we collect data of 24h measures session and in post processing we generate the GC (GBAS Correction). For this goal we use the software Pegasus V4.1 developed from EUROCONTROL. Generating the GC we have the possibility to study and monitor GBAS performance and integrity starting from a virtual functional architecture. The latter allows us to collect data without the necessity to found us authorization for the access to restricted area in airport where there is one GBAS installation.

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A Streaming XML Parser Supporting Adaptive Parallel Search (적응적 병렬 검색을 지원하는 스트리밍 XML 파서)

  • Lee, Kyu-Hee;Han, Sang-Soo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.8
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    • pp.1851-1856
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    • 2013
  • An XML is widely used for web services, such as SOAP(Simple Object Access Protocol) and REST (Representational State Transfer), and also de facto standard for representing data. Since the XML parser using DOM(Document Object Model) requires a preprocessing task creating a DOM-tree, and then storing it into memory, embedded systems with limited resources typically employ a streaming XML parser without preprocessing. In this paper, we propose a new architecture for the streaming XML parser using an APSearch(Adaptive Parallel Search) on FPGA(Field Programmable Gate Array). Compared to other approaches, the proposed APSearch parser dramatically reduces overhead on the software side and achieves about 2.55 and 2.96 times improvement in the time needed for an XML parsing. Therefore, our APSearch parser is suitable for systems to speed up XML parsing.

Design of a GCS System Supporting Vision Control of Quadrotor Drones (쿼드로터드론의 영상기반 자율비행연구를 위한 지상제어시스템 설계)

  • Ahn, Heejune;Hoang, C. Anh;Do, T. Tuan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.10
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    • pp.1247-1255
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    • 2016
  • The safety and autonomous flight function of micro UAV or drones is crucial to its commercial application. The requirement of own building stable drones is still a non-trivial obstacle for researchers that want to focus on the intelligence function, such vision and navigation algorithm. The paper present a GCS using commercial drone and hardware platforms, and open source software. The system follows modular architecture and now composed of the communication, UI, image processing. Especially, lane-keeping algorithm. are designed and verified through testing at a sports stadium. The designed lane-keeping algorithm estimates drone position and heading in the lane using Hough transform for line detection, RANSAC-vanishing point algorithm for selecting the desired lines, and tracking algorithm for stability of lines. The flight of drone is controlled by 'forward', 'stop', 'clock-rotate', and 'counter-clock rotate' commands. The present implemented system can fly straight and mild curve lane at 2-3 m/s.