• Tribology and Lubricants
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• v.37 no.4
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• pp.136-143
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• 2021

This paper presents the loosening behavior that occurs after the application of an external load to internal and external connection types of dental implants using the finite element method. We use fastening force between an abutment and a fixture to clamp the dental implant system; however, loosening and breakage may occur owing to cyclic external loads. In this study, we considered the initial fastening condition in the pre-load analysis and then investigated the change in stress and contact surface status when applying external loads. After the application of the initial fastening load, we verified that the internal connection-type model exhibited a relatively lower stress distribution than that of the external connection-type one. Moreover, we found that the former model showed a lower stress concentration after the application of the external load. In addition, after the application of this load, we found that the higher the shear load acting on the implant system, the higher the possibility of loosening. The study results showed the change in stress distribution and contact surface according to the connection type of the dental implants and the phenomenon of loosening by cyclic loads. We expect that the results of this study will be useful for the study of reliability and design of dental implant systems.

• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.1-6
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• 2021

Purpose: This study examined the effects of heel insoles on the static balance and leg muscle activity and posture control strategy during external perturbation. Methods: Thirty healthy young men participated in the study. The subjects underwent two experimental conditions: 1) no heel insole condition (0cm) and 2) wearing heel insole condition (5cm). The static balance was measured using an I-Balance device, which measured the change in the center of gravity (COG). The onset time of muscle activation and muscle activation of the erector spinae (ES), hamstring (HAM), gastrocnemius (GCM) were measured using surface EMG electrodes to determine the change in posture control strategy during external perturbation. Results: The speed and distance of COG were significantly higher in the wearing heel insoles condition than the no heel insole condition (p<0.05). In addition, significant differences in the onset time of the GCM, HAM, and ES muscle activation were observed when there was no heel insole condition during external perturbation (p<0.017). On the other hand, no significant differences in the onset time of muscle activation were observed between GCM and HAM when wearing the heel insole condition during external perturbation (p<0.017). Moreover, muscle activation of the GCM was significantly higher in the wearing heel insoles condition than the no heel insole condition during external perturbation (p<0.05). Conclusion: These findings suggest that heel insoles may have disadvantages, and increased efforts are needed to maintain balance and change the posture control strategy during external perturbation.

• Asia Marketing Journal
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• v.17 no.3
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• pp.73-103
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• 2015

According to Resource Dependence theory, an organization's behavior and strategy is affected by external resources. An organization has diverse resources interacting with environment. Because organization cannot focus on all those resources, it concentrates on its critical resources. In market environment, firm responds to other firms by controlling their internal critical resources or manages interdependency with environment to get market share. Thus Firm should choose best behavior and strategy when internal and external resources are change. When new brand enters, incumbents might change their strategy to protect their market share depending on critical value. More precisely, incumbents sharing market with entrant respond, but incumbents having competitive internal resources do not. In this article, we study incumbent's responses to a new brand entry and long-term effect. We show that how incumbents change their price strategy in reaction to the new brand' entry and also show these responses vary depending on interdependency of internal resources and external environments and ownership.

• Journal of the Korean Data and Information Science Society
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• v.14 no.2
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• pp.265-274
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• 2003

Time series data are influenced by the external events such as holiday, strike, oil shock, and political change, so the external events cause a sudden change to the time series data. We regard the observation as outlier that occurred as a result of external events. In general, it is called intervention if we know the period and the reason of external events, and it makes an analyst difficult to establish a time series model. Therefore, it is important that we analyze the styles and effects of intervention. In this paper, we considered the linear time series model with invention and compared with nonlinear time series models such as ARCH, GARCH model and also we compared with the combination prediction method that Tong(1990) introduced. In the practical case study, we compared prediction power with RMSE among linear, nonlinear time series model with intervention and combination prediction method.

• Journal of Sensor Science and Technology
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• v.13 no.4
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• pp.316-320
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• 2004

The possibility to use powder consisting of fullerite microcrystallines as a device sensitive to the external axial mechanical load is considered. We suppose that the change of conductivity of fullerite microcrystalline powder as a function of external mechanical stress will be useful for the creation of nanoscale devices of sensor electronics. This new effect based on changing of intermolecular distance between fullerene molecules due to the action of external mechanical force, which can change the distance between fullerene molecules because of weak van der Waals interaction exists. The founded effect is quite linear and sensitive to external mechanical stress is better then in well-known pressure transducers is based on silicon technology.

• Journal of the Korea Concrete Institute
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• v.11 no.6
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• pp.13-24
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• 1999

The external, unbonded prestressed concrete(PSC) members exhibit very different structural behavior from that of internal bonded PSC members because of eccentricity change and slip occurrence during loading process. The purpose of the present study is to propose the ultimate failure stresses of prestressing (PS) steels for those external unbonded PSC members. To this end, a comprehensive analysis has been made using the nonlinear finite element analysis program developed recently for external unbonded PSC members by authors. A series of major influencing variables have been included in the analysis. It was found that the span-depth ratio, neutral axis depth-effective depth ratio, load geometry, amount of ordinary steel, and prestressing steel ration have great influence for the ultimate failue stress of PS steel is preposed and is compared with experimental dat as well as existing formulas for internal unbonded members. The Comparison indicates that the proposed equation agrees relatively well with experimental data and that existing formulas including ACI and AASHTO equations show some discrepancies from experimental ones. The present study allows more realistic analysis and design of prestressed concrete structures with external unbonded tendons.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.355-360
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• 2007

The recent TFT-LCD Trend that is done large size gradually. As size of monitor great, though problem happens, it is that consumer's request which it makes monitor combined TV function. Monitor and TV are no difference externally greatly, but define difference happens as for backlight. An external electrode fluorescent lamp (EEFL) has an advantage of a long lifetime in the early stages of the study on plasma discharge, interest in the lamp continues. Researches on the operation of external electrode fluorescent lamps have focused mainly on its use of a type of high frequency (MHz). By performing high Luminance using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, EEFL presented the possibility of using it as a light source for back-lights. However, because EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significantly affected by frequency. Thus, this study verified the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell electromagnetic field simulation and examined the relationship between the change in the EEFL frequency and Luminance by measuring the optical characteristics.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.408-412
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• 2008

FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1) in Arabidopsis are homologous proteins that perform opposite functions: FT is an activator of flowering, and TFL1 is a repressor. It was shown before that change of a single amino acid (His88) of TFL1 to the corresponding amino acid (Tyr) of FT is enough to convert the floral repressor to an activator. However, structural basis of the functional conversion has not been understood. In our molecular dynamics simulations on modified TFL1 proteins, a hydrogen bond present in native TFL1 between the His88 residue and a residue (Asp144) in a neighboring external loop became broken by change of His88 to Tyr. This breakage induced conformational change of the external loop whose structure was previously reported to be another key functional determinant. These findings reveal that the two important factors determining the functional specificities of the floral regulators, the key amino acid (His88) and the external loop, are correlated, and the key amino acid determines the functional specificity indirectly by affecting the conformation of the external loop.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.41-51
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• 2018

Downwash from helicopter rotor blades and external winds from various maneuvering make an unguided rocket change its trajectory and range. For the prediction of the trajectory and range, it is essential to consider the downwash effect. In this study, an algorithm was developed to calculate 6-Degree-Of-Freedom(6 DOF) forces and moments exerting on the rocket, and total flight trajectory of a 2.75-inch unguided rocket in a helicopter downwash flow field. Using Actuator Disk Model(ADM) analysis result, the algorithm could analyze the entire trajectory in various initial launch condition such as launch angle, launch velocity, and external wind. The algorithm that considered the interference between a fuselage and external winds could predict the trajectory change more precisely than inflow model analysis. Using the developed algorithm, the attitude and trajectory change mechanism by the downwash effect were investigated analyzing the effective angle of attack change and characteristics of pitching stability of the unguided rocket. Also, the trajectory and range changes were analyzed by considering the downwash effect with external winds. As a result, it was concluded that the key factors of the rocket range change were downwash area and magnitude which effect on the rocket, and the secondary factors were the dynamic pressure of the rocket and the interference between a fuselage and external winds. In tailwind case which was much influential on the range characteristics than other wind cases, the range of the rocket rose as increasing the tailwind velocity. However, there was a limit that the range of the rocket did not increase more than the specific tailwind velocity.

• Journal of Nutrition and Health
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• v.34 no.2
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• pp.222-229
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• 2001

This study describes the application of the stages of change construct to fat intake by examining the associations of the stages of change with nutritional status and beliefs on health behavior. Data were obtained from apparently healthy 596 adults(326 females and 270 males) residing in large cities. Stages of change assessed by an algorithms based on 6 items were designed each subject into one of the 5 stages: precontemplation(PC), contemplation(CO), preparation(PR), action(AC) and maintenance(MA). Beliefs on health behavior were assessed by self efficacy as well as 4 belief scales from the Locus of Illness Control(LIC) developed using factor analysis such as internal disease cure and prevention and external disease cure and prevention. Energy and fat intakes were measured by a 39 item short form food frequency questionnaire. Regarding the 5 stages of change, MA stage comprised the largest group(37.9%), followed by Ac(30.7%), PC(11.4%), CO(10.4%) and PR(9.6%). Subjects who were females, older or healthier were more likely to belong to either AC or MA. Stage assignment of individuals was corroborated by their nutritional variables. Those in PC had the most energy and fat and those in MA ate the least for females. BMI was higher in PR than any other stages for both males and females. Those in PC were distinctive in that they were more externally oriented in terms of health control showing higher scores on external disease prevention(for males) and external disease cure(for females), and lower score on internal disease cure. On the other hand, those in MA received the highest scores on internal disease prevention and self efficacy, which suggested that they were more internally oriented. Canonical discriminant function analysis indicated that the 5 stages were importantly discriminated by BMI, self efficacy, internal disease prevention and external disease prevention for males and by fat intake, self efficacy and external disease cure variables for females. The results of our study confirm differences in stages of change in fat intake in terms of nutritional status and beliefs on heath behavior and indicate the need for taking these phases of change into account in nutrition advice. (Korean J Nutrition 34(2) : 222-229, 2001)