• 대한치과보철학회지
• /
• 제35권3호
• /
• pp.517-534
• /
• 1997

It has been held that excessive mechanical forces to the osseous and soft tissues of the TMJ result in joint dysfunction. Understanding the stress pattern on TMJ is very important in TMJ research. But, it is very difficult to measure directly the biomechanical stress distribution in the TMJ when the mandible is loaded. Therefore, stress distribution in the TMJ during functional movement was studied through animal experiment or mathematical model. It was observed and compared the stress distribution occuring in the working and balancing condyle when lower right canine, lower right first molar and lower right second molar were clenched by the three dimensional finite element analysis. Also, stress distribution in the working and balancing condyles were observed and compared when $20^{\circ}$ forward and buccal bite forces were applied to the first molar. The results were as follows : 1. Stress distribution in the condyles during unilateral clenching of the first molar, second molar, canine showed no difference. In the working condyle, tensile force was concentrated on the lateral aspect of the condylar articular surface and condylar neck. And compressive force was concentrated on the anteromedial and lateral aspect of condyle. In the balancing condyle, tensile and compressive forces were concentrated on the lateral aspect of the condylar articular surface and stress transmission to the temporal bone was not observed. 2. When lateral forces were applied to the first molar, tensile forces were concentrated on the medial aspect of the condylar neck and condylar posterior surface in working and balancing condyle. Compressive force was concentrated on the anteromedial and lateral surface of the condyle and stress transmission to the temporal bone was not observed. 3. During unilateral clenching, stress in the working condyle decreased as the occlusal load moved posteriorly while the stress in the balancing condyle increased. when lateral force was applied to first molar, the incremental amount of stress was greater than vertical load. 4. During unilateral clenching, the average balancing/working condyle stress ratio was 2.52. There was a greater concentration of stress in the balancing condyle. The ratio increased as the occlusal load moved posteriorly and decreased considerably when lateral forces were applied to the first molar.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.115-120
• /
• 2003

In this study, smoke movement in tunnel fires was investigated with various aspect ratio(0.5, 0.667, 1.0, 1.5, 2.0) of tunnel cross section. Reduced-scale experiments were carried out under the Froude scaling using 8.27 kW ethanol pool fire. Temperatures were measured under the ceiling and vertical direction along the center of the tunnel. Smoke front velocity and temperature decrease rate were reduced as higher aspect ratio of the tunnel cross-section. Smoke movement was evaluated by analysis of vertical temperature distribution 3 m downstream from the fire source. Elevation of smoke interface according to N percent rule was under about 60% of tunnel height.

• 한국물환경학회지
• /
• 제27권5호
• /
• pp.680-688
• /
• 2011

This study was performed to find out the distribution aspect of benthic macroinvertebrates according to altitude in a mountain stream (a main stream: Buk stream, a tributary: Hangye stream) of Seoraksan. The survey was conducted from August to November in 2010. All survey sites were very sound because the mountain was being maintained as a protection area of the national park. Water quality and the composition of substrata were similar in all sites. Benthic macroinvertebrates of 3 phyla, 4 classes, 9 orders and 84 species occurred in the stream. Along with the decline of altitude, shredders of the functional feeding groups (FFGs) decreased, while collector filterers increased. In particular, collector filterers increased sharply at the altitude of 600 ~ 500 m (S.E.L.). Benthic macroinvertebrates showed low similarity between the uppermost site and the lower sites. Altitude appeared to be a significant factor that influence the structure and distribution of benthic macroinvertebrate community.

• 유통과학연구
• /
• 제20권3호
• /
• pp.13-22
• /
• 2022

Purpose: Thisstudy aims to measure the attitudes of Generation Z in Jakarta towards advertisements containingCOVID-19 information. Research design, data and methodology: This study is a quantitative method with partial least square structural equation modeling (PLS-SEM) with SMART PLS as an analytical tool. The sample size is 216 participants was obtained randomly through a questionnaire distributed online. This study consisted of exogenous variables (advertising content, value, irritation, and economic benefits), endogenous variables (attitudes towards advertising), and some moderating roles. Results: The results of thi study explain that this generation's attitude towards advertising is affected by the content and value aspects embedded in advertisements. Value can be formed from creativity in making advertising content as interesting and informative as possible. Interestingly, this study also found that the irritation aspect and economic benefits had no effect on the audience's attitude towards the advertisement. Neither the irritating aspect of advertising nor the economic value that is formed acts as a moderator of the content and the value of the ad. Conclusions: The ongoing pandemic and periodic adjustments to government policies regarding COVID-19, these results can be compared with other advertisements for future studies, especially those using the same variables as this study.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 학술대회
• /
• pp.297-301
• /
• 2008

The flight vehicles have cavities such as wheel wells and bomb bays. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves. Resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. The flow field is observed to oscillate in the "shear layer mode" with low aspect ratio. In the present study, numerical analysis was performed for cavity flows by the unsteady compressible three dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with Wilcox's $\kappa$-$\omega$ turbulence model. The flow field is observed to oscillate in the shear layer mode" with large aspect ratio. Based on the SPL(Sound Pressure Level) analysis of the pressure variation at the cavity trailing edge, the dominant frequency was analyzed and compared with the results of Rossiter's formul. The aero-acoustic wave analyzed with CPD(Correlation of Pressure Distribution).

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년 추계학술대회논문집
• /
• pp.297-301
• /
• 2008

The flight vehicles have cavities such as wheel wells and bomb bays. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves. Resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. The flow field is observed to oscillate in the "shear layer mode" with low aspect ratio. In the present study, numerical analysis was performed for cavity flows by the unsteady compressible three dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with Wilcox's ${\kappa}-{\varepsilon}$ turbulence model. The flow field is observed to oscillate in the "shear layer mode" with large aspect ratio. Based on the SPL(Sound Pressure Level) analysis of the pressure variation at the cavity trailing edge, the dominant frequency was analyzed and compared with the results of Rossiter's formul. The aero-acoustic wave analyzed with CPD(Correlation of Pressure Distribution).

• 마케팅과학연구
• /
• 제16권1호
• /
• pp.1-11
• /
• 2006

저작권의 거래 및 통제를 매우 낮은 비용으로 구현한 DRM(Digital Right Management)에 의해 디지털 컨텐츠의 유통에 획기적인 변화가 가능할 것으로 생각된다. 본 논문은 DRM 기술의 도입에 의해 개별 이용자가 유통의 주체가 되는 초유통(Super Distribution)의 적용 가능성과 다양한 가격설정 방식이 적용될 수 있다는 점에 주목하였다. 우선 초유통을 통해 이용자들의 정보획득비용을 감소시키고 이를 통해 수요를 증가시킬 수 있으며 컨텐츠 제작자 측면에서도 유통에 따른 비용을 크게 감소시킬 수 있음을 논하였다. 또한 DRM은 기존의 총량가격 방식 이외에 사용기간 또는 사용 횟수 등 다양한 기준에 따른 가격설정을 가능하게 하며 이를 통해 기업의 이윤과 소비자 총효용 모두 증가할 수 있음을 보였다. 이러한 DRM 기술의 특성은 디지털 컨텐츠 유통의 효율성을 증대시키고 컨텐츠의 질과 다양성 및 가격정책을 통한 사업자들간 차별화를 가능케 하여 산업의 동적인 성장을 가속화 할 수 있을 것으로 생각된다.

• 유통과학연구
• /
• 제12권11호
• /
• pp.101-111
• /
• 2014

Purpose - This study aims to verify the construct of the service quality suitable to the characteristics of the business center, to develop the scale that can measure the service quality objectively, compare the diverse business centers in Korea, and present desirable methods of business center management and operation. Research design, data, and methodology - In the first stage, literature research and focus group interviews with current users and actual business experts of business centers were conducted. In addition, 69 early stage scale items were derived. In the second stage, a Delphi survey was conducted on the experts of business and academic circles. The measurement items in the early stage were supplemented and revised. The content validity rate (CVR) of 69 measures was computed and then the experts' opinions were used. As a result, the business center service quality scale, made up of 9 organizing factors and 36 measurement items, was constructed. In the third stage, a survey was conducted on the occupants who were currently using the business center. It was to confirm if the developed business center service quality scale could be actually utilized. The data of 435 samples collected were used. To refine the scale items, the exploratory factor analysis (EFA) was conducted repeatedly. Results - The business center service quality scale, made up of 8 factors and 33 items, was developed again. The 8 factors are reliability, speed, kindness, specialty, responsibility, appearance, convenience, and public interest. The reliability coefficient (Cronbach's Alpha) of each factor is greater than .7. Thus, it was confirmed that there was reliability in the measurement items. Further, the model suitability was verified using the confirmatory factor analysis (CFA), and the convergent validity and the discriminant validity were verified. This proved the construct validity. Through this process, the Korea Business Center Service Quality Scale was developed. Based on factor analysis, the developed business center service quality (BCSQ) scale consists of 4 aspects, 8 factors, and 33 items, comprising the "process quality" aspect: reliability (3 items), speediness (4 items), kindness (3 items) factors, the outcome quality aspect: expertise (3 items), responsibility (5 items) factors, the environment quality aspect: appearance (5 items), convenience (3 items) factors, and the public interest aspect: public interest (7 items) factor. However, according to CFA, the BCSQ scale consists of a total of 4 aspects, 8 factors, and 33 items, comprising the "process quality" aspect: reliability (3 items), speediness (3 items), kindness (3 items) factors, the outcome quality aspect: expertise (2 items), responsibility (4 items) factors, the environment quality aspect: appearance (3 items), convenience (2 items) factors, and the public interest aspect: public interest (3 items) factor. Conclusions - The BCSQ scale could serve as a diagnostic tool that will allow business center managers to determine service areas that are weak and in need of attention, and to improve the service quality of the business center.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1993년도 추계학술대회 논문집
• /
• pp.660-665
• /
• 1993

An elastic model is developed to predict the average thermal residual stresses in the matrix and fiber of a misoriented short fiber composite. The thermal residual stresses are induced by the mismatch in the coefficient of the thermal expansion of the matrix and fiber when the composite is subjected to a uniform temperature change. The model considers two special cases of fiber misorientation ; two-dimensional in-plane and three-dimensional axisymmetric. The analytical formulation of the model is based on Eshelby's equivalent inclusion method and is nuque in that it is able to account for interactions among fibers. The model is more general than past models and it is able to treat prior analyses of the simpler composite systems as extram cases. The present model is to investigate the effects of fiber volume fraction, distribution type, distribution cut-off angle, and aspect ratio on thermal residual stress for both in-plane and axisymmetric fiber misorientation. Fiber volum fraction, aspect ratio, and disturbution cut-off angle are shown to have more significant effects on the magnitude of the thermal residual stress than fiber distrubution type for both in-plane and axisymmetric misorientation.

• Journal of Welding and Joining
• /
• 제26권6호
• /
• pp.92-96
• /
• 2008

An investigation was performed to predict residual stress redistribution for the crack propagation initially through tensile residual stress field. The analytical method, which is based on Dugdale model by finite element analysis using elastic analysis method considering the superposition principle, was proposed to estimate the redistribution of residual stress caused by crack propagation. The various aspect of distribution of residual stress caused by crack propagation was examined based on the configuration change of specimen. The analysis results show that the aspect of redistribution of residual stress caused by crack propagation depends on the width of the specimen provided that the initial distribution of residual stress is identical.