• Structural Engineering and Mechanics
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• 제58권1호
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• pp.121-142
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• 2016

The national standard being used in Turkey for suspended ceiling systems (SCS) regulates material and dimensional properties but does not contain regulations regarding installation instructions which cause substandard applications of SCSs in practice. The lack of installation instructions would potentially affect the dynamic performance of these systems. Also, the vast majority of these systems are manufactured using substandard low-quality materials, and this will inevitably increase SCS related damages during earthquakes. The experimental work presented here focuses on the issue of dynamic performance of SCSs with different types of carrier systems (lay-on and clip-in systems), different weight conditions, and material-workmanship qualities. Moreover, the effects of auxiliary fastening elements, so called seismic perimeter clips, in improving the dynamic performance of SCSs were experimentally investigated. Results show that clip-in ceiling system performs better than lay-on system regardless of material and workmanship qualities. On the other hand, the quality aspect becomes the most important parameter in affecting the dynamic performance of lay-on type systems as opposed to tile weights and usage of perimeter clips. When high quality system is used, tile weight does not change the performance of lay-on system, however in poor quality system, tile weight becomes an important factor where heavier tiles considerably decrease the performance level. Perimeter clips marginally increase the dynamic performance of lay-on ceiling system, but it has no effect on the clip-in ceiling system under the shaking levels considered.

• 한국안전학회지
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• 제18권2호
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• pp.40-45
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• 2003

To evaluate the smoke control systems, the large eddy simulation turbulence model based Fire Dynamics Simulate was applied to a 2m $\times$ 2m $\times$ 2.4m room with an opening. The smoke removal rate was investigated for three different smoke control systems: ventilation, extraction and pressurization. When the opening was closed, the smoke removal rates of the smoke control systems were almost the same as expected. The pressurization system showed a lower smoke removal rate compared with the other two smoke control systems for the room with the opening, and hence the pressurization system might not be efficient for a place with large openings. It was shown that the lower extraction flowrate is, the longer time the ventilation system requires to remove smoke. From these results, the ventilation system is recommended for subway stations where several large openings exist.

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.131-139
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• 2020

PURPOSE. The purpose of this study is to evaluate the repair bond strength of a nanohybrid resin composite to three CAD/CAM blocks using different intraoral ceramic repair systems. MATERIALS AND METHODS. Three CAD/CAM blocks (Lava Ultimate, Cerasmart, and Vitablocks Mark II) were selected for the study. Thirty-two specimens were fabricated from each block. Specimens were randomly divided into eight groups for the following different intraoral repair systems: Group 1: control group (no treatment); Group 2: 34.5% phosphoric acid etching; Group 3: CoJet System; Group 4: Z-Prime Plus System; Group 5: GC Repair System; Group 6: Cimara System; Group 7: Porcelain Repair System; and Group 8: Clearfil Repair System. Then, nanohybrid resin composite (Tetric Evo Ceram) was packed onto treated blocks surfaces. The specimens were thermocycled before application of repair systems and after application of composite resin. After second thermal cycling, blocks were cut into bars (1 × 1 × 12 ㎣) for microtensile bond strength tests. Data were analyzed using two-way ANOVA and Tukey's HSD test (α=.05). RESULTS. Cimara System, Porcelain Repair, and Clearfil Repair systems significantly increased the bond strength of nanohybrid resin composite to all CAD/CAM blocks when compared with the other tested repair systems (P<.05). In terms of CAD/CAM blocks, the lowest values were observed in Vitablocks Mark II groups (P<.05). CONCLUSION. All repair systems used in the study exhibited clinically acceptable bond strength and can be recommended for clinical use.

• 한국정보시스템학회지:정보시스템연구
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• 제6권2호
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• pp.147-163
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• 1997

The usages of the relational database systems have been increased nowadays. However there is a constraint that the standard query language for a database system requests users to know the exact condition for a query. In this paper a FSQL(Fuzzy SQL) systems is proposed and implemented for the imprecise queries which do not include the exact condition. Moreover this system can supply the obvious results for the queries effectively. We define a simple fuzzy query language and use a method using the metadatabase to implement the FSQL system. This FSQL system can be combined with a relational database system without any painful effort.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.284-284
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• 2000

In adaptive fuzzy control systems. fuzzy systems are used to approximate the unknown plant nonlinearities. Until now. most of the papers in the field of controller design for nonlinear system using fuzzy systems considers the affine system with fixed grid-rule structure based on system state availability. This paper considers observer-based nonlinear controller and dynamic fuzzy rule structure. Adaptive laws for fuzzy parameters for state observer and fuzzy rule structure are established so that the whole system is stable in the sense of Lyapunov.

• 한국철도학회논문집
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• 제20권1호
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• pp.55-63
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• 2017

철도에 사용되고 있는 Safety critical systems 중 하나인 연동장치는 relay-based systems에서 computer-based systems으로 급속히 변환되고 있다. computer-based interlocking systems (CBI)의 안전성확보가 중요한 문제 중 하나로 떠오르고 있다. CBI를 구성하는 연동논리 software는 시스템 안전성에 직접적으로 영향을 미치는 부분 중 하나이다. Formal methods 중 하나인 "Z"notation은 이 software 안전성 확보를 위해 software 명세에 많이 사용되고 있다. 본 논문에서는 "Z"notation을 이용하여 연동논리 일부분을 구현하였으며, Z/EVES를 이용하여 검증을 하였다.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3460-3463
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• 2021

Present computing power and enhanced technology is progressing at a dramatic rate. These systems can unravel complex issues, assess and control processes, learn, and-in many cases-fully automate production. There is no doubt that technological advancement is improving many aspects of life, changing the landscape of virtually all industries and enhancing production beyond what was thought possible. However, the human is still a part of these systems. Consequently, as the advancement of systems transpires, the role of humans within those systems will unavoidably continue to adapt as well. Due to the human tendency for error, this technological advancement should compel a persistent emphasis on human error reduction as part of maximizing system efficiency and safety-especially in the context of the nuclear industry. Within this context, as new systems are designed and the role of the human is transformed, human error should be targeted for a significant decrease relative to predecessor systems and an equivalent increase in system stability and safety. This article contends that optimizing the roles of humans and machines in the design and implementation of new types of automation in nuclear facility systems should involve human error reduction without ignoring the essential importance of human interaction within those systems.

• 한국화재소방학회논문지
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• 제21권4호
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• pp.1-11
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• 2007

본 연구에서는 할론 1301 및 이산화탄소를 비롯한 가스계소화설비의 성능을 시험하고 평가하기 위한 가장 중요한 핵심 요소인 배관내 약제비율, 관경비 등 소화성능에 영향을 미치는 가스계소화설비의 제한사항 및 성능확보에 필요한 요소에 대하여 연구하였다. 또한 본 연구에서는 관련 국내외 기준 분석 및 국내 가스계소화설비의 성능평가에 관한 인정기준(KFIS 002)에 따른 시스템 성능시험을 실시하고 결과를 비교 분석하였다.

• 제어로봇시스템학회논문지
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• 제18권5호
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• pp.433-438
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• 2012

In this paper, a operation network system equipped with onboard wireless communication systems and ground-based mission control systems is proposed for swarm flight of small UAVs. This operating system can be divided into two networks, UAV communication network and ground control system. The UAV communication network is intend to exchange the informations of navigation, mission and flight status with minimum time delay. The ground control system consisted of mission control systems and UDP network. Proposed operation network system can make a swarm flight of various UAVs, execute complex missions decentralizing mission to several UAVs and cooperte several missions. Finally, PILS environments are developed based on the total operating system.

• 대한기계학회논문집
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• 제19권2호
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• pp.374-381
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• 1995

In this paper, integration methods for stiff constrained mechanical systems are studied to analyze dynamic response of the stiff mechanical system efficiently. The stiff, non-stiff systems are identified by using eigenvalues of the Jacobian of the systems. To integrate both stiff system and non-stiff system efficiently a new switching method between the non-stiff differential equation solver and the stiff differential equation solver is presented.