• Smart Structures and Systems
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• 제9권1호
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• pp.71-104
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• 2012

In this research, a typical tension-leg type of floating platform incorporated with an innovative concept of underwater tuned liquid column damper system (UWTLCD) is studied. The purpose of this study is to improve the structural safety by means of mitigating the wave induced vibrations and stresses on the offshore floating Tension Leg Platform (TLP) system. Based on some encouraging results from a previous study, where a Tuned Liquid Column Damper (TLCD) system was employed in a floating platform system to reduce the vibration of the main structure, in this study, the traditional TLCD system was modified and tested. Firstly, the orifice-tube was replaced with a smaller horizontal tube and secondly, the TLCD system was combined into the pontoon system under the platform. The modification creates a multipurpose pontoon system associated with vibration mitigation function. On the other hand, the UWTLCD that is installed underwater instead would not occupy any additional space on the platform and yet provide buoyancy to the system. Experimental tests were performed for the mitigation effect and parameters besides the wave conditions, such as pontoon draught and liquid-length in the TLCD were taken into account in the test. It is found that the accurately tuned UWTLCD system could effectively reduce the dynamic response of the offshore platform system in terms of both the vibration amplitude and tensile forces measured in the mooring tethers.

• Steel and Composite Structures
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• 제9권3호
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• pp.239-253
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• 2009

This paper reviews the concept of tensegrity structures and proposes a new type of dismountable steel tensegrity grids for possible deployment as light-weight roof structures. It covers the fabrication of the prototype structures followed by their instrumentation, destructive testing and numerical analysis. First, a single module, measuring $1m{\times}1m$ in size, is fabricated based on half-cuboctahedron configuration using galvanised iron (GI) pipes as struts and high tensile stranded cables as tensile elements. Detailed instrumentation of the structure is carried out right at the fabrication stage. The structure is thereafter subjected to destructive test during which the strain and the displacement responses are carefully monitored. The structure is modelled and analyzed using finite element method (FEM) and the model generated is updated with the experimental results. The investigations are then extended to a $2{\times}2$ grid, measuring $2m{\times}2m$ in size, fabricated uniquely by the cohesive integration of four single tensegrity modules. After updating and validating on the $2{\times}2$ grid, the finite element model is extended to a $8{\times}8$ grid (consisting of 64 units and measuring $8m{\times}8m$) whose behaviour is studied in detail for various load combinations expected to act on the structure. The results demonstrate that the proposed tensegrity grid structures are not only dismountable but also exhibit satisfactory behaviour from strength and serviceability point of view.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1302-1312
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• 2008

Relaxed Static Stability(RSS) has been applied to improve flight performance of modern version supersonic jet fighters. Flight control systems are necessary to stabilize an unstable aircraft and to provide adequate handling qualities. Also, flight control systems of modern aircraft employ many safety measure to cope with emergency situations such as a pilot unknown attitude flight conditions of an aircraft in night flight-testing. This situation is dangerous because the aircraft can lose if the pilot not take recognizance of situation. The system called the "Pilot Activated Recovery System" or PARS, provided a pilot initiated automatic maneuver capable of an aircraft recoveries in situations of unusual attitudes, speed and altitude. This paper addresses the concept of PARS with AARS(Automatic Attitude Recovery System), ATCS(Automatic Thrust Control System) and MARES(Minimum Altitude Recovery Estimation System), and this control law is designed by nonlinear control law design process based on model of supersonic jet trainer. And, this control law is verified by real-time pilot evaluation using an HQS(Handling Quality Simulator). The result of evaluation reveals that the these systems support recovery of an aircraft unusual attitude and speed, and improve a safety of an aircraft.

• 한국지진공학회논문집
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• 제3권4호
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• pp.1-10
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• 1999

지진 시 지반의 자유장 운동은 국지적 지반조건에 의하여 크게 영향을 받으며 내진설계에 앞서 지반조건을 고려한 부지응답특성평가를 수행하여야 한다. 본 논문은 부지고유의 지반거동 평가를 위하여 필요한 절차를 국내 내진기준과 외국의 기술현황 조사를 바탕으로 제안하였다. 부지응답특성 평가의 개요를 설명하고 1차원 등가선형 해석에 필요한 지반자료 획득을 위한 지반조사계획 기반조사기법, 저변형율 및 고변형율 영역에서의 지반의 변형거동특성, 현장 및 실내시험결과를 이용한 부지특성평가방법들을 제안하였다 또한 제안된 절차를 따라 수행된 인천 지역의 부지특성평가방법들을 제안하였다 또한 제안된 절차를 따라 수행된 인천 지역의 부지응답특성평가 예를 포함하였다.

• Nuclear Engineering and Technology
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• 제50권4호
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• pp.532-541
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• 2018

Decision support systems are a key focus of research on developing control rooms to aid operators in making reliable decisions and reducing incidents caused by human errors. For this purpose, models of complex systems can be developed to diagnose causes or consequences for specific alarms. Models applied in safety systems of complex and safety-critical systems require rigorous and reliable model building and testing. Multilevel flow modeling is a qualitative and discrete method for diagnosing faults and has previously only been validated by subjective and qualitative means. To ensure reliability during operation, this work aims to synthesize a procedure to measure model performance according to diagnostic requirements. A simple procedure is proposed for validating and evaluating the concept of multilevel flow modeling. For this purpose, expert statements, dynamic process simulations, and pilot plant experiments are used for validation of simple multilevel flow modeling models of a hydrocyclone unit for oil removal from produced water.

• 한국멀티미디어학회논문지
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• 제1권1호
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• pp.109-119
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• 1998

본 논문은 형식기술기법으로 기술된 차세대지능망 응용프로토콜(INAP: Intelligent Network Application Protocool)로부터 추상시험스위트 (Abstract Test Suite) 자동생성에 대한 연구 결과를 기술한다. 시험 자동생성을 위해 RCP tour(Rural Chinese Postman tour) 개념과 UIO 시퀀스 (UIO:Unique Input Output Sequence) 개념을 응용하였다. SDL(System Description Language) 형식기술 기법으로 명세화된 INAP명세로부터 생성한 I/O FSM(Input/Output Finite State Machine)을 중간모델로 하여 UIO 시퀀스를 정의하고, 정의된 UIO 시퀀스를 RCP tour 개념과 결합하여 최적의 시험 시퀀스를 생성하였다. 본 논문에서는 또, 생성된 시험 스위트의 오류커버영역 예측방법을 제시하고, 마지막으로 표준화된 시험 표기법인 TTCN(Tree and Tabular Combined Notation)으로 생성된 시험스위트의 변환방법도 제시한다.

• 대한간호학회지
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• 제43권2호
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• pp.194-202
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• 2013

Purpose: This study was done to develop and test a scale to measure the partnership between pediatric nurses and hospitalized children's parents. Methods: Instrument development process included construct identification based on concept analysis using the hybrid model of Shuwartz-Barcott and Kim (2000), a process which generated 42 initial items. This number was reduced to 35 items through content validity tests by 5 experts and face validity tests by 5 pediatric nurses and 5 parents of hospitalized children. The preliminary Pediatric Nurse Parent Partnership Scale (PNPPS) was administered to 186 pediatric nurses and 163 parents at eleven children's wards in four hospitals. Data were analyzed using item analysis, factor analysis, Pearson correlation coefficients, and Cronbach's alpha. Results: Thirty-four items were selected for the final scale. Seven factors evolved from the factor analysis, which explained 68.4% of the total variance. The internal consistency, Cronbach's alpha, was .96 and reliability of the subscales ranged from .66 to .93. Conclusion: The PNPPS demonstrated acceptable validity and reliability. It can be used to assess the partnership of pediatric nurses and parents in practice and research.

• 대한안전경영과학회지
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• 제22권1호
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• pp.61-68
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• 2020

The purpose of this study was to measure the job aspiration and examine the relationship between that and job satisfaction for wage-earners using the fourth Korean Working Conditions Survey(KWCS). We use the stochastic frontier model for measuring the job aspiration and testing its effect on the job satisfaction. Fstochastic frontier model is introduced to explain that each company potentially produces less than it might due to a degree of job aspiration, measured by decomposing the residuals. In this model framework, it can be regard that the upper bound of the job satisfaction is the ideal frontier, and the bias between the ideal condition and the reality is the job aspiration. If this concept is applicable to the job aspiration, we can measure this bias and investigate a relationship with the job satisfaction. We find that there exists the job aspiration, and it is significantly negatively correlated with the job satisfaction. This result supports that if job aspiration increases, job satisfaction level decreases.

• 한국항공우주학회지
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• 제33권8호
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• pp.26-33
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• 2005

틸트로터 비행체 개념인 스마트무인기는 수직이착륙, 장기체공, 그리고 고속비행성능을 동시에 요구한다. 이와 같은 세 가지의 상반된 비행체 성능의 구현을 위해서는 비행모드별로 최적의 공력성능을 갖도록 하는 플랩시스템의 운용이 불가피하다. 스마트무인기의 플래퍼론을 설계하는데 있어서 다양한 후보 형상을 생성하고, 이들 형상에 대해 전산유동해석을 수행하여 각 형상에 대한 공력성능을 분석하였다. 이와 같은 공력성능과 실제형상의 구조적인 단순성을 고려하여 스마트무인기의 최종 플래퍼론 형상을 선정하였으며, 40% 축소모델에 대한 풍동시험을 통해 선정된 플래퍼론에 대한 성능을 검증하였다.

• 센서학회지
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• 제14권3호
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• pp.144-149
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• 2005

In this paper, we introduce the variation of ride characteristics for HSR 350x(Korea High Speed Train project) through on-line test during about 3 years. The concept of term "ride comfort" is equivocal. Generally it is evaluated as the vehicle vibration. The ride comfort for HSR 350x has been assessed by statistical method according to UIC 513R. The testing results show that HSR 350x has no problems from the viewpoint of the comfort ride on the high speed line and conventional line and that 1st and 2nd suspensions play an important role in the ride characteristics for high speed train.