• Title/Summary/Keyword: System-level design

Search Result 4,254, Processing Time 0.028 seconds

Optimization of Biomimetic Two-level Hierarchical Adhesive System (자연모사 2층 구조 응착시스템의 최적화)

  • Kim, Tae-Wan
    • Tribology and Lubricants
    • /
    • v.26 no.2
    • /
    • pp.129-135
    • /
    • 2010
  • Geckos have a unique ability to cling to ceilings and walls utilizing dry adhesion. Their foot pads are covered by a large number of small hairs (setae) that contain many branches per seta with a lower level of spatulae. Their fibrillar structure is the primary source of high adhesion. In this study, we construct the adhesion design database for biomimetic adhesive system. A simple idealized fibrillar structure consisting of single array of beams is modeled. The fibers are assumed as oriented cylindrical cantilever beams with spherical tip. We consider three necessary conditions; buckling, fracture and sticking of fiber structure, which constrain the allowed geometry. The adhesion analysis is performed for the attachment system in contact with rough surfaces with different s values for different main design variables-fiber radius, aspect ratio and material elastic modulus and so on. The developed adhesion design databases are useful for understanding biological systems and for guiding of fabrication of the biomimetic attachment system.

Level 1 probabilistic safety assessment of supercritical-CO2-cooled micro modular reactor in conceptual design phase

  • So, Eunseo;Kim, Man Cheol
    • Nuclear Engineering and Technology
    • /
    • v.53 no.2
    • /
    • pp.498-508
    • /
    • 2021
  • Micro reactors are increasingly being considered for utilization as distributed power sources. Hence, the probabilistic safety assessment (PSA) of a direct supercritical-CO2-cooled fast reactor, called micro modular reactor (MMR), was performed in this study; this reactor was developed using innovative design concepts. It adopted a modular design and passive safety systems to minimize site constraints. As the MMR is in its conceptual design phase, design weaknesses and valuable safety insights could be identified during PSA. Level 1 internal event PSA was carried out involving literature survey, system characterization, identification of initiating events, transient analyses, development of event trees and fault trees, and quantification. The initiating events and scenarios significantly contributing to core damage frequency (CDF) were determined to identify design weaknesses in MMR. The most significant initiating event category contributing to CDF was the transients with the power conversion system initially available category, owing to its relatively high occurrence frequency. Further, an importance analysis revealed that the safety of MMR can be significantly improved by improving the reliability of reactor trip and passive decay heat removal system operation. The findings presented in this paper are expected to contribute toward future applications of PSA for assessing unconventional nuclear reactors in their conceptual design phases.

Estimation of the Isolator Displacement for the Performance Based Design of Nuclear Power Plants (원전 적용을 위한 면진장치의 성능기반 설계 변위 추정)

  • Kim, Jung Han;Choi, In-Kil;Kim, Min Kyu
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.18 no.6
    • /
    • pp.291-299
    • /
    • 2014
  • There has been an increasing demand for introducing a base isolation system to secure the seismic safety of a nuclear power plant. However, the design criteria and the safety assessment methodology of a base isolated nuclear facility are still being developed. A performance based design concept for the base isolation system needs to be added to the general seismic design procedures. For the base isolation system, the displacement responses of isolators excited by the extended design basis earthquake are important as well as the design displacement. The possible displacement response by the extended design basis earthquake should be limited less than the failure displacement of the isolator. The failure of isolators were investigated by an experimental test to define the ultimate strain level of rubber bearings. The uncertainty analysis, considering the variations of the mechanical properties of isolators and input ground motions, was performed to estimate the probabilistic distribution of the isolator displacement. The relationship of the displacement response by each ground motion level was compared in view of a period elongation and a reduction of damping. Finally, several examples of isolator parameters are calculated and the considerations for an acceptable isolation design is discussed.

Innovative Design and Practice in Horizontal Skyscraper-ChongQing Raffles

  • Li-Gang, Zhu
    • International Journal of High-Rise Buildings
    • /
    • v.11 no.3
    • /
    • pp.197-205
    • /
    • 2022
  • One of important design challenges in Chongqing Raffles City Plaza project is Sky Bridge structural design and its connection scheme in high level. This article systematically describes the structural system and its design and analysis methodology, with discussing the impacts on structural performance due to different connection approaches. The seismic isolation scheme in high level is innovatively adopted to the final design. Under the conditions of various load cases, the different models and assumptions are implemented. A full assessment on Sky Bridge's structural performance, seismic isolation, and its connection is conducted in terms of seismic performance based design. By co-operating with architecture, MEP and other disciplines, the structural economy index is fulfilled.

Object-Oriented Database Application for An Integrated Structural Design Process (일관 구조설계 시스템 구축에 있어서 객체지향 데이터 베이스의 도입)

  • 천진호;김홍국;이병해
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1993.04a
    • /
    • pp.79-85
    • /
    • 1993
  • An integrated structural design system can define and process complex design information that occurs in each of the design stages for flexible cooperation. It can also reduce human error on sequential design steps: preliminary design, analysis and detailed design. Therefore, it's very important to have consistent semantic expression and procedure for structural design information that has complex relationships. In this study, we introduce the object-oriented concepts and object-oriented database thechnique that provides high level semantic expression in order to develop an integrated structural design system.

  • PDF

Experimental Evaluation of Unmanned Aerial Vehicle System Software Based on the TMO Model

  • Park, Han-Sol;Kim, Doo-Hyun;Kim, Jung-Guk;Chang, Chun-Hyon
    • Journal of Computing Science and Engineering
    • /
    • v.2 no.4
    • /
    • pp.357-374
    • /
    • 2008
  • Over the past few decades, a considerable number of studies have been conducted on the technologies to build an UAV (Unmanned Aerial Vehicle) control system. Today, focus in research has moved from a standalone control system towards a network-centric control system for multiple UAV systems. Enabling the design of such complex systems in easily understandable forms that are amenable to rigorous analysis is a highly desirable goal. In this paper, we discuss our experimental evaluation of the Time-triggered Message-triggered Object (TMO) structuring scheme in the design of the UAV control system. The TMO scheme enables high-level structuring together with design-time guaranteeing of accurate timings of various critical control actions with significantly smaller efforts than those required when using lower-level structuring schemes based on direct programming of threads, UDP invocations, etc. Our system was validated by use of environment simulator developed based on an open source flight simulator named FlightGear. The TMO-structured UAV control software running on a small computing platform was easily connected to a simulator of the surroundings of the control system, i.e., the rest of the UAV and the flight environment. Positive experiences in both the TMO-structured design and the validation are discussed along with potentials for future expansion in this paper.

Unified Design Methodology and Verification Platform for Giga-scale System on Chip (기가 스케일 SoC를 위한 통합 설계 방법론 및 검증 플랫폼)

  • Kim, Jeong-Hun
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.47 no.2
    • /
    • pp.106-114
    • /
    • 2010
  • We proposed an unified design methodology and verification platform for giga-scale System on Chip (SoC). According to the growth of VLSI integration, the existing RTL design methodology has a limitation of a production gap because a design complexity increases. A verification methodology need an evolution to overcome a verification gap. The proposed platform includes a high level synthesis, and we develop a power-aware verification platform for low power design and verification automation using it's results. We developed a verification automation and power-aware verification methodology based on control and data flow graph (CDFG) and an abstract level language and RTL. The verification platform includes self-checking and the coverage driven verification methodology. Especially, the number of the random vector decreases minimum 5.75 times with the constrained random vector algorithm which is developed for the power-aware verification. This platform can verify a low power design with a general logic simulator using a power and power cell modeling method. This unified design and verification platform allow automatically to verify, design and synthesis the giga-scale design from the system level to RTL level in the whole design flow.

An Experimental Study on the Optimistic Recognition Level of Public Address System as a Soundscape Application Facility (사운드스케이프 적용을 위한 옥외 P.A. 시스템 적정 인지레벨에 관한 실험적 연구)

  • Song, Min-Jeong;Jang, Gil-Soo;Shin, Hoon;Shin, Young-Gyu;Lee, Tai-Kang
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.726-729
    • /
    • 2006
  • As a active soundscape facility, P.A. system is a useful instrument to give place identity and vitality by letting out music, environmental music, bird singing sound etc. In this study, to know the optimistic distance and sound level range of introducing sound, sound levels due to distance were measured and subject responses were checked by questionnaire. Levels from 64dB to 71dB are recommended by subjects. And the optimistic level of introducing level is related with level variance of sound source. The results of this study could used for street furniture location design and P.A. system output level.

  • PDF

Development of Control System for Ultrasonic Spray Pyrolysis Deposition (초음파 분무 열분해 증착 제어 시스템 개발)

  • Kim, Kyu-Eon;Kim, Yeong-Heum;Lee, Chibum
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.23 no.4
    • /
    • pp.385-391
    • /
    • 2014
  • A control system for ultrasonic spray pyrolysis deposition was developed that can coat a large size glass panel with a transparent conductive oxide. It consists of several ultrasonic atomizer devices to cover a large area and a host computer for individually controlling the devices. The sub-controller in an ultrasonic atomizer device can adjust the flow rate of the atomized conductive oxide gas by setting the flow rate of the solution and regulating the level of the solution in the tank. To construct a feedback control loop for level regulation, a level sensor that utilized an infrared distance sensor and an electric circuit for adjusting the ultrasonic oscillator were developed. The host program was also developed, which can monitor and control the sub-controllers. A proportional-integral controller was developed for a simplified model, and its operation was verified through an experiment.

Acoustic Enclosure Design of Diesel Engine (디젤엔진의 음향차폐장치 설계)

  • Choi, Hyun;Kim, Young-Chan;Kim, Doo-Hoon;Jeon, Jae-jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1997.04a
    • /
    • pp.481-487
    • /
    • 1997
  • The development of transportation and construction equipment has required higher engine power and lower operation cost. The sound which the engine emits often degrade the performance of the whole system which adopts that engine. Specially the marine engine requires high restriction on the noise level for the customer's comfort and safety. The noise and vibration of Diesel engine must be carefully considered in the early design step. The double antivibration system is effective to increase the efficiency of antivibration, and the acoustic enclosure for reducing the noise level. 2 DOF model was effective to estimate the antivibration performance, which allows to determine the mass of the engine bed and the specification of the engine mount. The mass distribution of the enclosure system can be considered effectively by using the FEM model. The design contains structurally rigid engine bed by FEM, which is for reducing the influence of the flexible vibration, rubber mount selection as well as the acoustic enclosure design.

  • PDF