• Computers and Concrete
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• 제31권6호
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• pp.469-484
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• 2023

The response mechanism of simply supported two-way reinforced concrete (RC) slabs under fire was numerically studied from the view of stress redistribution using the finite element software ABAQUS. Results show that: (1) Simply supported two-way RC slabs undergo intense stress redistribution, and their responses show four stages, namely elastic, elastic-plastic, plastic and tensile membrane stages. There is no cracking in the fire area of the slabs until the tensile membrane stage. (2) The inverted arch effect and tensile membrane effect improve the fire resistance of the two-way slabs. When the deflection is L/20, the slab is in an inverted arch effect state, and the slab still has a good deflection reserve. The deformation rate of the slab in the tensile membrane stage is smaller than that in the elastic-plastic and plastic stages. (3) Fire resistance of square slabs is better than that of rectangular slabs. Besides, increasing the reinforcement ratio or slab thickness improves the fire resistance of the slabs. However, an increase of cover thickness has little effect on the fire resistance of two-way slabs. (4) Compared with one-way slabs, the time for two-way slabs to enter the plastic and tensile cracking stage is postponed, and the deformation rate in the plastic and tensile cracking stage is also slowed down. (5) The simply supported two-way RC slabs can satisfy with the requirements of a class I fire resistance rating of 90 min without additional fire protection.

• Journal of Biosystems Engineering
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• 제22권2호
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• pp.177-188
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• 1997

A pepper harvester using a pair of counter rotating helically wound cylinders as a pepper removal mechanism has been developed. Pepper harvesting by machines under the customary cultivation practice was expected to lower land productivity, that most farmers were concerned about. As one way to compensate for loss in land productivity by machine harvest, experts on pepper cultivation suggested change of both varieties and plant density per area. From the view of machine design, their suggestion implied that distance between rows should be narrower and height of the pepper removal mechanism could be shorter. Experiments to improve perfect pepper recovery ratio and to reduce size of the pepper removal mechanism was accomplished. In order to be a economically feasible harvester, minimum pepper recovery ratio was required to be greater or equal to 80%. The research goal was achieved by both reducing the diameter of the wire-helices from 30 cm to 18 cm and increasing rotational speed of the wire-helices up to 425 rpm. The best perfect pepper recovery ratio was 82.3%. Validity of experiment design and interpretation on statistical analysis were discussed. To understand the pepper removal mechanism properly, a pepper removal theory based physics was judged to be necessary.

• 한국국방경영분석학회지
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• 제6권2호
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• pp.129-149
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• 1980

In medical follow-up, equipment lifetesting, various military situations, and other fields, one often desires to calculate survival probability as a function of time, p(t). If the observer is able to record the time of occurrence of the event of interest (called a 'death'), then an empirical, non-parametric estimate may simply by obtained from the fraction of survivors after various elapsed times. The estimation is more complicated when the data are truncated, i.e., when the observer loses track of some individuals before death occurs. The product-limit method of Kaplan and Meier is one way of estimating p(t) when the mechanism causing truncation is independent of the mechanism causing death. This paper proposes jackknife estimators of logistic trans-formation and compares it to the product-limit method. A computer simulation is used to generate the times of death and truncation from a variety of assumed distributions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.653-656
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• 2005

This paper introduces design, fabrication and experiment process of a novel scanner for the high speed AFM(Atomic Force Microscope). A proper design modification is proposed through analyses on the dynamic characteristics of the existing linear motion stages using a dynamic analysis program, Recurdyn. Since the scanning speed of each direction is allowed to be different, the linear motion stage for the high-speed scanner of AFM can be so designed to have different resonance frequencies for the modes with one dominant displacement in the desired directions. One way to achieve this objective is to use one-direction flexure mechanism for each direction and to mount one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separates the frequencies of the two vibration modes with one dominant displacement in each desired direction, hence, the coupling between the motions in the two directions. In addition, a pair of actuators is used for each axis to decrease the cross talks in the two motions and gives a force large enough to actuate the slow motion stage, which carries the fast motion stage. After these design modifications, a novel scanner with scanning speed higher than 10 Hz can be achieved to realize undistorted images in the high speed AFM.

• 한국실내디자인학회논문집
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• 제25권6호
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• pp.116-126
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• 2016

In modern society which changes from quantity-seeking society to value-seeking one, people's various lifestyles have great effect on consumption patterns and work as an important factor in choosing hotels. The fact that design hotels, which provide unique experiences with differentiated and sensitive designs by reflecting various lifestyles, recently attract attention can be understood in the same context. As a matter of fact, design hotels recently serve as destinations as they become cultural and artistic icons which reflect customer lifestyles. Especially, the designs of lobby spaces in hotels play deciding role in customers' choices while representing the nature of hotels. In this respect, under the premise that the kinds of accumulated experiences are different depending on lifestyles and preferences for specific interior spaces are influenced by association mechanism formed by experiences, this study analyzed lobby spaces of design hotels which focus on specific lifestyles from the perspective of association mechanism based on experiences. As the method of analysis, this study classified the types of lifestyles and conducted case analysis to investigate what association mechanism works to enhance the preference of design hotels by types. Study classified lifestyles into experiential activity type, social meeting type, fashion-pursuing type and hideout-preferring type and analyzed cases of lobby designs in design hotels. The results of this case analysis are as follows; First, experiential activity type mainly utilized quasi-association and approach association through senses and social meeting type utilized quasi-association and memory association through emotions while fashion-pursuing type utilized quasi-association and presumption association through intuition and hideout-preferring type utilized quasi-association and approach association through thoughts. Second, it was found that most lobby designs are characterized by association mechanism in visual formative nature and that in temporal spatial nature working in complex way, and, through such process of association expansion, space stories are created. Stories of spaces created this way become unique identities of design hotels that provide new experiences for customers.

• International Journal of Advanced Culture Technology
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• 제6권2호
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• pp.117-122
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• 2018

As evidenced through rapidly growing digital repositories and web resources, automatic metadata generation is becoming ever more critical, especially considering the costly and complex operation of manual metadata creation. Also, automatic metadata generation is apt to consistent metadata application. In this sense, metadata quality and interoperability can be enhanced by utilizing a mechanism for automatic metadata generation. In this article, a mechanism of automatic metadata extraction called ExMETA is introduced in order to alleviate issues dealing with inconsistent metadata application and semantic interoperability across ever-growing digital collections. Conceptual graph, one of formal languages that represent the meanings of natural language sentences, is utilized for ExMETA as a mediation mechanism that enhances the metadata quality by disambiguating semantic ambiguities caused by isolation of a metadata element and its corresponding definition from the relevant context. Hence, automatic metadata generation by using ExMETA can be a good way of enhancing metadata quality and semantic interoperability.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1728-1732
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• 2005

Gear trains are used in many machinery for variable speed ratios. Typical shapes of gear trains are two categories: simple gear trains and planetary gear trains. Generally the methods of the design typical shapes are two way. One of the methods is trailblazing design and the other is selective design in available types. This paper presents the mechanism types when input rotating velocity and output rotating velocity are maintained for useful planetary gear reducers of twelve types. Also, this paper gives the applicable example about rotating velocity of the gear axis, carrier velocity and the organized gear specifications

• 산업융합연구
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• 제21권10호
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• pp.57-63
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• 2023

평활근 수축에 대한 감초산(glycyrrhizic acid)의 효과를 연구하고자 하였고 관련 상세 기전을 결정하기 위해 glycyrrhizic acid가 agonist-sensitive하게 평활근 수축한다는 가설을 제시하였다. S/D rats의 평활근을 수조 내 준비하였고 신호 변환기에서 평활근에 의한 운동 신호가 전기적 신호로 변환되어 생리기록기에 표시되는 데이터는 일원배치 분산분석으로 분석하였다. 재미있게도, 감초산은 불화물, 트롬복산 유사체 등 굵은 미세섬유성 조절성 수축제에 의한 평활근 수축을 중등도로 억제하였고 (농도 0.01, 0.03, 0.1 mM 불화물에서 p=0.113, 0.008, 0.004 (Student's t-test), p=0.113, 0.008, 0.004 (One way ANOVA), 그리고 0.01, 0.03, 0.1 mM 트롬복산 유사체에서 p=0.156, 0.004, 0.003 (Student's t-test), p=0.156, 0.004, 0.003 (One way ANOVA)) 포볼 에스테르 등 가는 미세섬유성 조절성 수축제에 의한 평활근 수축에 대해 효과가 소실되었다 (0.01, 0.03, 0.1 mM 포볼 에스테르에서 p=0.392, 0.086, 0.065 (Student's t-test), p=0.392, 0.086, 0.065 (One way ANOVA)). 이러한 결과는 내피 기능이 억제된 평활근에서 감초산은 평활근 내피에서 EDRF (NO) 생성 효과 외에 주로 ROCK 활성 감소 등 평활근에 대한 직접적 효과를 통해 최종적으로 평활근에서 악틴-미오신 상호작용을 제한하여 평활근을 이완시키는 것으로 생각된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.331-336
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• 1995

In this past decade, industrial robot have substituted human workers successfully in certain areas, however, the applications are limited due to the shortcoming in their mechanism and control strategies. Many researchers, therefore, have focused on improving the mechanical and sensory capabilities. Developing mult-degree-of-freedom end effectors, in other words robot hands, is one of the topics that researchers have begun to improve the limitation. A set of direct drive type servo-pneumatic finger joint has been developed for a dexterous robot hand. To control the pneumatic finger joints, a prototype 4/3-way proportional control valve has been designed and tested as a preliminary, research for the control of the pneumatic finger joints. A series of experiments have been conducted to verify the performance characteristics of the valve and the conventional proportional error contral with minor-loop compensation has been used to control the anguar position of the finger joints.

• 대한전기학회논문지:전력기술부문A
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• 제54권2호
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• pp.88-96
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• 2005

At present, the Korean electricity industry is undergoing restructuring and the Cost Based-generation Pool(CBP) market is being operated preparing for Two Way Bidding Pool(TWBP) market open. As the circumstance of the traditional system is changed according to power system deregulation, the simulation tool which should reflect market code providing market operating mechanism is needed to analyze an electricity market. This paper presents the development of an unique market simulator, Market Modeling and Price Simulator(MMPS) that is designed to imitate the Korean electricity market considering uniform price. The MMPS is developed in VB.NET and is composed of two modules that consist of market modeling and price simulation interfacing access database program. To evidence the features and the performance of MMPS, a small two way bidding market with 12-bus system and one way bidding market for generator competition will be presented for the electricity market simulations using MMPS.