• 동력기계공학회지
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• 제18권5호
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• pp.60-65
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• 2014

This research examined an immediate loading capable of providing a masticatory function and financial affordability while satisfying every requirement of a useful immediate loading. In this research, numerical value analysis was performed on couple-type posterior teeth implants developed by making up for the problems of extant implants. As a result of examining the effects of external impacts on extant implants and their deformation, relatively lager deformations separated from a molar were found concerning molar deformation implant with the maximum deformation level being approximately 1.657mm. In this research, the improved implant showed much improvement in terms of impact analysis in its deformation dispersion status after unloading the impulsive load from a punch. As for the case of hepf, about 1.657mm occurred but the improved model showed about 0.9217mm, exhibiting 55.6% advancement.

• Structural Engineering and Mechanics
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• 제75권2호
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• pp.175-191
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• 2020

In this study, multi-story structures are actively controlled using metaheuristic algorithms. The soil conditions such as dense, normal and soft soil are considered under near-fault ground motions consisting of two types of impulsive motions called directivity effect (fault normal component) and the flint step (fault parallel component). In the active tendon-controlled structure, Proportional-Integral-Derivative (PID) type controller optimized by the proposed algorithms was used to achieve a control signal and to produce a corresponding control force. As the novelty of the study, the parameters of PID controller were determined by different metaheuristic algorithms to find the best one for seismic structures. These algorithms are flower pollination algorithm (FPA), teaching learning based optimization (TLBO) and Jaya Algorithm (JA). Furthermore, since the influence of time delay on the structural responses is an important issue for active control systems, it should be considered in the optimization process and time domain analyses. The proposed method was applied for a 15-story structural model and the feasible results were found by limiting the maximum control force for the near-fault records defined in FEMA P-695. Finally, it was determined that the active control using metaheuristic algorithms optimally reduced the structural responses and can be applied for the buildings with the soil-structure interaction (SSI).

• 복식
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• 제62권7호
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• pp.185-204
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• 2012

There are lots of sexual images in the contemporary media, and this is due to many of the media formats, such as television, magazines, and the Internet, using these images to relay various messages to the people. The media uses these sexual images (i.e. woman in a bikini) in order to use sex and eroticism as a marketing tool to the audience. Unlike other men's magazines, which actually have many female readers, Maxim magazine's readers are made of mostly men, and because of this, their magazine covers are usually filled with sexy women celebrities, such as singers or actors; images that can attract the general men. This study puts its focus on evaluating Maxim magazine's marketing strategy. The strategy of targeting men in their 20's and 30's, who were not interested in reading, but were impulsive and visually oriented. The study looked at magazine covers from November 2002 (the start of the magazine) to October 2008 (the peak period of its sales), and a total of 72 images were analyzed. For each image, 5 things were recorded (model's occupation, clothing style, hairstyle, makeup, pose and gaze).

• International Journal of Aeronautical and Space Sciences
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• 제11권1호
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• pp.49-57
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• 2010

Several pyrotechnic devices are employed over the course of satellite's missions, generally for the separation of structural subsystems and deployment of appendages. Firing of pyrotechnic devices results in impulsive loads characterized by high peak acceleration and high frequency content which can cause failures of various flight hardware elements and small components. Thus, accurate prediction of acceleration level in various components of spacecraft due to pyrotechnic devices is important. In this paper, two methods for pyroshock prediction, an empirical model and statistical energy analysis in conjunction with virtual mode synthesis, are applied to predict shock response of a low altitude earth observation satellite during launch vehicle separation. The predicted results are then evaluated through comparison with the shock test results.

• 한국소음진동공학회논문집
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• 제16권6호
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• pp.658-664
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• 2006

Shock vibrations are usually experienced in vehicles excited by impulsive input, such as bumps. The frequency weighting functions of the current standards in ISO 2631 and BS 6841 are to help objectively predict the amount of discomfort of stationary vibration. This experimental study was designed to develop frequency weighting shape for shock vibration having various fundamental frequencies from 0.5 to 16Hz. The specks were produced from the response of single. degree-of-freedom model to a half-sine force input. Fifteen subjects used the magnitude estimation method to judge the discomfort of vertical shock vibration generated on the rigid seat mounted on the simulator. The magnitudes of the shocks, expressed in terms of both peak-to-peak value and un-weighted vibration dose values (VDVs) , were correlated with magnitude estimates of the discomfort. The frequency weighting shapes from the correlation were developed and investigated having nonlinearity due to the magnitude of the shock.

• Earthquakes and Structures
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• 제16권5호
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• pp.523-532
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• 2019

Different types of gas reservoir such as Liquid Natural Gas (LNG) are among the strategic infrastructures, and have great importance for any government or their private owners. To keep the tank and its contents safe during earthquakes especially if the contents are of hazardous or flammable materials; using seismic protection systems such as base isolator can be considered as an effective solution. However, the major deficiency of this system can be the large deformation in the isolation level which may lead to the failure of bearing system. In this paper, as a solution, the efficacy of an optimally designed combined vibration control system, the combined laminated rubber isolator and rotational friction damper, is investigated to evaluate the enhancement of an existing metal tank response under both far- and near-field earthquakes. Responses like impulsive and convective accelerations, base shear, and sloshing height are studied herein. The probabilistic framework is used to consider the uncertainties in the structural modeling, as well as record-to-record variability. Due to the high calculation cost of probabilistic methods, a simplified structural model is used. By using the Mont-Carlo simulation approach, it is revealed that this combined isolation system is a highly reliable system which provides considerable enhancement in the performance of reservoir, not only leads to the reduction of probability of catastrophic failure of the tank but also decrease the reservoir damage during the earthquake. Moreover, the relative displacement of the isolation level is controlled very well by this combined system.

• 유통과학연구
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• 제20권2호
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• pp.1-9
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• 2022

Purpose: The online distribution channel has attracted the attention of retailers by potential impact on consumers' purchase intention. The objectives of this study are to provide an insight into how to encourage consumers' impulse buying behavior on commercial website as well as attempts to reveal factors that influence consumers' impulsive buying behavior in the online shopping environment. Research design, data and methodology: The research framework is based on the stimulus-organism-response (S-O-R) framework. The Meta-analysis method carried out the research, gathering data from 37 published studies. Results: The research findings suggest that intrinsic motivations such as perceived ease of use, perceived enjoyment, and online flow experience play a significant role in boosting consumers' hedonic value when buying and online. In addition, these findings help online retailers use appropriate marketing stimuli such as offering pricing incentives, promotion tactics, and improved communication effectiveness. Also, obtaining a better grasp of how to build a website to improve the consumer experience generally helps consumers feel the urge to buy impulsively and act without hesitation. Conclusions: This research confirms a direct positive relationship between marketing stimuli and hedonic shopping value, which may support an applied theoretical framework for future research and provide managerial implications for retailers in online distribution channels.

• 한국콘텐츠학회논문지
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• 제21권1호
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• pp.684-697
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• 2021

본 연구는 우울, 불안, 충동성의 청소년의 개인 심리적 위험요인이 스마트폰 중독(일상장애, 가상지향, 내성, 금단)과 자아탄력성(활력성, 낙관성, 호기심, 대인관계)에 미치는 영향을 규명하고자 함에 있다. 이러한 검증을 통해 청소년들의 스마트폰 중독과 관련된 개인 심리적 위험요인들과 자아탄력성, 스마트폰 중독의 통합적 모형이 타당한지 알아보고, 이를 통해 청소년들의 스마트폰 중독을 예방하고 관련 문제를 해결하기 위한 방안을 제시하는데 본 연구의 목적이 있다. 이러한 연구목적을 달성하기 위해 서울과 수도권에 재학 중인 청소년 356명을 연구대상으로 2019년 8월 1일부터 9월 30일까지 약 2개월간 조사하여 결과를 분석하였다. 본 연구의 연구결과는 다음과 같다. 첫째, 청소년의 "스마트폰 중독요인(우울, 불안, 충동성)은 청소년의 자아탄력성(활력성, 낙관성, 호기심, 대인관계)에 부(-)의 영향을 미치는 것으로 나타났다. 둘째, 청소년의 "스마트폰 중독요인(우울, 불안, 충동성)은 청소년의 "스마트폰 중독(일상장애, 가상지향, 내성, 금단)"에 정(+)의 영향을 미치는 것으로 나타났다. 셋째, 청소년의 "자아탄력성(활력성, 낙관성, 호기심, 대인관계)"은 "스마트폰 중독(일상장애, 가상지향, 내성, 금단)"에 부(-)의 영향을 미치는 것으로 나타났다. 본 연구의 의의는 스마트폰 중독에 영향을 미치는 개인 심리적 위험요인을 살펴봄과 함께 자아탄력성을 활용하여 스마트폰 중독에 미치는 영향을 미시적으로 분석하여 청소년들의 스마트폰 중독을 예방하고 관련 문제를 해결하기 위한 방안을 제시하였다는데 연구의 의의가 있다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권3호
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• pp.239-245
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• 2017

As a new technical approach, wave energy converter by using vertical motion of water in the multiple water chambers were developed to realize actual wave power generation as eco-environmental renewable energy. And practical use of wave energy converter was actually to require the following conditions: (1) setting up of the relevant device and its application to wave power generation in case that severe wave loading is avoided; (2) workability in installation and maintenance operations; (3) high energy conversion potential; and (4) low cost. In this system, neither the wall(s) of the chambers nor the energy conversion device(s) are exposed to the impulsive load due to water wave. Also since this system is profitable when set along the jetty or along a long floating body, installation and maintenance are done without difficulty and the cost is reduced. In this paper, we describe the system which consists of a float, a shaft connected with another shaft, a rack and pinion arrangement, a ratchet mechanism, and rotary type generator(s). Then, we present the dynamics model for evaluating the output electric power, and the results of numerical calculation including the effect of the phase shift of up/down motion of the water in the array of water chambers aligned along the direction of wave propagation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1409-1416
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• 2010

It is essential to predict a blasting-induced excavation damage zone (EDZ) beyond the proposed excavation line of a tunnel because the unwanted damage area requires extra support system for tunnel safety. Complicated blasting process which may hinder a proper characterization of the damage zone can be effectively represented by two loading mechanisms. The one is a dynamic impulsive load generating stress waves outwards immediately after detonation. The other is a gas pressure that remains for a relatively long time. Since the gas pressure reopens up the arrested cracks and continues to extend some cracks, it contributes to the final formation of EDZ induced by blasting. This paper presents the simple method to evaluate EDZ induced by gas pressure during blasting in rock. The EDZ is characterized by analyzing crack propagation from the blasthole. To do this, a model of the blasthole with a number of radial cracks of equal length in an infinite elastic plane is considered. In this model, the crack propagation is simulated by using three conditions, the crack propagation criterion, the mass conservation of the gas, and the adiabatic condition. As a result, the stress intensity factor of the crack generally decreases as crack propagates from the blasthole so that the length of the crack is determined. In addition, the effect of rock properties, initial number of cracks, and the adiabatic exponent are investigated.