• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.04a
• /
• pp.791-796
• /
• 2011

In order to understand long range wave propagation in railway tracks, it is required to identify how far vibrations can travel along a rail. To answer this question, the attenuation characteristics of the main propagating waves are required as a function of distance. In this work, it is identified which wave types predominantly propagate on various regions of the rail cross-section. Then decay rates of propagating waves in railway tracks are investigated for frequencies up to 80 kHz. A numerical method called the Wavenumber Finite Element (WFE) method is utilized to predict dispersion curves and decay rates for a rail on a continuous foundation. In order to validate the simulated results, measurements have been performed on a test track and an operational railway track. The measured results are compared with the output of the simulations and good agreements are found between them.

• Journal for History of Mathematics
• /
• v.30 no.3
• /
• pp.163-183
• /
• 2017

In this study we reveal that there were positive changes after the practicums of pre-service math teachers, in that, they changed contents of class and the way of explanation in order to enhance students' understanding, and provided opportunities for students to participate in the class. In addition, they made more use of textbooks in their class instead of depending on their experience acquired before the practicums. However, no difference was found before and after their practicums, neither in their review of lessons nor in their use of simple 'question and answer' strategies. In this regard, we suggest continuous researches be conducted in order to enhance pre-service mathematics teachers' teaching ability, especially those which is hard to be acquired in a short period of time. And, reflecting the results of the research, systematic development and operation of the curriculum are required in the teacher training institutes.

• Journal of the Chungcheong Mathematical Society
• /
• v.23 no.3
• /
• pp.425-434
• /
• 2010

Here we see that the $p-Ces{\grave{a}}ro$ operators, the generalized $Ces{\grave{a}}ro$ operators of order one, the discrete generalized $Ces{\grave{a}}ro$ operators, and their adjoints are all posinormal operators on ${\ell}^2$, but many of these operators are not dominant, not normaloid, and not spectraloid. The question of dominance for $C_k$, the generalized $Ces{\grave{a}}ro$ operators of order one, remains unsettled when ${\frac{1}{2}}{\leq}k<1$, and that points to some general questions regarding terraced matrices. Sufficient conditions are given for a terraced matrix to be normaloid. Necessary conditions are given for terraced matrices to be dominant, spectraloid, and normaloid. A very brief new proof is given of the well-known result that $C_k$ is hyponormal when $k{\geq}1$.

• Journal of the Chungcheong Mathematical Society
• /
• v.37 no.1
• /
• pp.27-40
• /
• 2024

In this paper, we consider the higher-order HartreeFock equations. The higher-order linear Schrödinger equation was introduced in [5] as the formal finite Taylor expansion of the pseudorelativistic linear Schrödinger equation. In [13], the authors established global-in-time Strichartz estimates for the linear higher-order equations which hold uniformly in the speed of light c ≥ 1 and as their applications they proved the convergence of higher-order Hartree-Fock equations to the corresponding pseudo-relativistic equation on arbitrary time interval as c goes to infinity when the Taylor expansion order is odd. To achieve this, they not only showed the existence of solutions in L² space but also proved that the solutions stay bounded uniformly in c. We address the remaining question on the convergence of higherorder Hartree-Fock equations when the Taylor expansion order is even. The distinguished feature from the odd case is that the group velocity of phase function would be vanishing when the size of frequency is comparable to c. Owing to this property, the kinetic energy of solutions is not coercive and only weaker Strichartz estimates compared to the odd case were obtained in [13]. Thus, we only manage to establish the existence of local solutions in H^s space for s > $\frac{1}{3}$ on a finite time interval [-T, T], however, the time interval does not depend on c and the solutions are bounded uniformly in c. In addition, we provide the convergence result of higher-order Hartree-Fock equations to the pseudo-relativistic equation with the same convergence rate as the odd case, which holds on [-T, T].

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.3
• /
• pp.487-493
• /
• 2008

Recently, in proportion to the remarkable development of dentistry and income increases it is growing more and more a concern about changed awareness in appearance. In this study, it had a grasp of the purpose for university hospital visiting, the motive of the commencement for orthodontic treatment and a method of the treatment as well as term. Based on these, the aim of this study is to keep more of the information between parent and doctors for mutual understanding and to grasp the characteristics for the needs of orthodontic treatment. In order to conduct researches, there has made a survey of 150 persons among orthodontic patients' parents who visit CBNU hospital, the pediatric dentistry. The study has found the results like these. 1. There was a question about the reason to visit CBNU hospital in the department of pediatric dentistry for orthodontic treatment. 52.1% of respondents, the survey found, were more likely to receive a good medical service. 25% of them were counselled from a relative or an acquaintance. 16.7% of them were recommended by another dental clinic. 2. There was a question about the expected orthodontic treatment period, when at first hospital visiting. 37.5% of the respondents answered that it was a 'more than 2 years', 12.5% of them said 'from 12 months to 18 months'. 3. There was a question about the reason to receive orthodontic treatment. 58.3% of the respondents, the survey found, answered the reason was parents' concern about the malocclusion of their children, 12.5% of them said a the orthodontic problem pointed out by entourages. 4. There was a question about the method of orthodontic treatment for patients who visit the department in pediatric dentistry. 41.7% of the respondents said that it was used as 'an intra-oral fixed appliance', 29.2% of them said 'an intra-oral removable appliance', 2.1% of them said 'an extra-oral appliance', 5. There was a question about the waiting time for treatment after a dental appointment. 60.4% of the respondents said 'from 5 minutes to 10 minutes', 4.1% of them said 'from 15 minutes to 30 minutes'. There was a question about the extent of an acceptable waiting time. It was answered to 'from 5 minutes to 10 minutes' by 60.4% of them, 2.1% of them said 'from 15 minutes to 30 minutes'.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.11
• /
• pp.735-741
• /
• 1999

The monitoring and assessment on the insulation condition of generator stator windings have been an important task of utility companies. The interest for the assessment of insulation condition has been increasing due to the need to keep old generating equipment reliable in order to extend the equipment life and to increase the generating capacity. Even though many developments and research activities for the condition assessment of generator insulation have been performed for decades, the assessment criterion in order to consistently predict the actual insulation condition is still in question. In this paper, the correlation between the parameters and the insulation condition is analyzed through the various non-destructive diagnostic tests in order to establish the assessment criterion on insulation deterioration of generator stator windings. By analyzing the correlation, PDI(Partial Discharge Index) as a novel parameter for the assessment criterion on insulation diagnosis of stator winding is proposed and verified.

• Journal of English Language & Literature
• /
• v.55 no.1
• /
• pp.199-213
• /
• 2009

From the perspective of pragmatics, language is a mode of act that works in the order of motive and performs human purpose. The function of language is then primarily performative rather than informational or significative. Pragmatics, however, encounters a tough question: what is the relation of the linguistic act to meaning? Many language theories including pragmatic theories admit the autonomy of meaning while defining language as act. But in Deleuze and Peirce we find examples of maximalist pragmatics that denies the autonomy of meaning. However, Deleuze and Peirce are different in their view on the function of meaning. For Deleuze, language is the transmission of act, what he calls 'order-word.' He rejects meaning except as the minimal condition for the transmission. But his theory turns out to be contradictory in that meaning as the minimal condition is actually the function of constants that he denies for order-words that are always variables. On the contrary, Peirce's pragmatism as a radical pragmatics does not exclude meaning. For him, language is interpretative act serving the purpose of understanding reality, which is performed through the function of meaning and 'habit.' This shows that meaning is indispensable to language even in maximalist pragmatics.

• Journal of Korean society of Dental Hygiene
• /
• v.9 no.2
• /
• pp.137-146
• /
• 2009

In pediatric dentistry, sedation therapy is one of methods for managing children's behavior, and various types of sedation therapy are being used. Thus, this study surveyed the awareness of and satisfaction with sedation therapy in 204 parents who visited the Pediatric Dentistry using a self-administered questionnaire during the period from June to December 2008 in order to get information necessary in behavior management for pediatric patients, and obtained results as follows. 1. The most common path of learning about sedation therapy was dentistry (49.5%), and the most common reason for choosing sedation therapy was 'The child was young'(42.3%), which was followed by 'The child is too afraid'(18.8%), 'There are many teeth to be treated'(16.0%), 'To adjust the number of visits'(11.3%), and 'For behavior management'(3.1%). 2. Most of the parents felt anxiety about sedation therapy, and the reasons for the anxiety were 'The child was young'(33.0%), 'Worry about side effects'(31.3%), 'Worry about recovery of consciousness'(25.7%), 'Worry about the blunting of intellectual abilities'(7.6%), and others (2.4%). 3. Satisfaction with sedation therapy was higher in men than in women, and was high in order of 'Stationing of an anesthetist', 'One time completion of treatment', and 'Cautions'. Statistically significant difference was observed between men and women only in question "Have you ever heard about sedation therapy?"(p=0.018). 4. According to age, satisfaction with sedation therapy was highest in parents whose child was less than 48 months old. Satisfaction was high in order of 'Stationing of an anesthetist', 'One time completion of treatment', and 'Cautions', 'Choice of sedation therapy', and statistically significant difference was observed according to age only in question "Have you ever heard about sedation therapy?"(P=0.005). 5. Positive correlation was observed among questions on satisfaction with sedation therapy. In the survey on the awareness of and satisfaction with sedation therapy in parents visiting the dentistry, awareness and satisfaction were generally high with regard to the parents' choice of sedation therapy, but many of the parents answered that they chose sedation therapy and felt anxiety because their child was young. The results of this study need to be considered for behavior management in pediatric dentistry and there should be systematic education and promotion of sedation therapy.

• Journal of Korean society of Dental Hygiene
• /
• v.10 no.4
• /
• pp.617-625
• /
• 2010

Objectives : The research which sees collected information about dentistry infection management recognition of the patients and the infection management which the medical treatment consumer does in necessity is what, grasped and satisfaction and became the fundamental data which makes the hospital will be able to trust about dentistry image rise and dentistry environment of the medical treatment consumer who assists a dentistry character executed. Methods : From 2009 April 1st until May 28th 233 people common people who have the experience which visits a Gyeongsangnam-do area dentistry the object with the entry question law which sleeps did and the data analysis SPSS, 12.0 For Window under using produced each question item by frequency and a ratio, the analytical degree of infection management One - Way ANOVA stamps and executed t-test. Results : Information experience experienced about dentistry infection of the investigation object person to be, appeared with 74.7% and the after that dentistry assistance at the time of conduct change which experiences the answer back regarding of Former times attentively observes organization disinfecting' was most with 46.6%. The protective equipments wearing goal of the dentistry medical attendance appeared the dentistry medical attendance and patient protection 77.7%, dentistry medical attendance protection 12.9%, by patient protection 9.4% order. Before medical treatment starting of the dentistry medical attendance the hand Does not confirm' appeared 72.1%, with. The hand washing, is whole and the degree which appears is high with 4.11 points the stamp. Is high there was a possibility of knowing the thing about the recording infection where the educational background will be high and considers statistically the difference which was visible Conclusions : The education which is active and continuous is necessary about infection management and sets the guides which are standardized to the patients and about infection management and about infection prevention and exposes from dentistry practices well to emboss the thing is thought that there is a necessity to plant a trust feeling about the dentistry where the patients assist.

• Journal of Internet Computing and Services
• /
• v.13 no.2
• /
• pp.1-11
• /
• 2012

The purpose of this paper is to estimate 'willingness to pay' for mobile data service by using contingent valuation method with double bounded dichotomous choice question. The findings are as follows.: First, the willingness to pay of mobile data service is considerably lower than current retail price. Second, the perceived degree of mobile data service such as awareness and benefit recognition is positively related to the willingness to pay of mobile data service. Our results suggest that active promotion and strengthening of the content of mobile data service are needed in order to enhance the profitability of mobile operators. The analysis results will be used to set the mobile operator's pricing strategy and to build up a successful communication policies in the mobile ecosystem.