• Communications of the Korean Mathematical Society
• /
• v.25 no.4
• /
• pp.655-669
• /
• 2010

In this paper we propose new primal-dual interior point methods (IPMs) for $P_*(\kappa)$ linear complementarity problems (LCPs) and analyze the iteration complexity of the algorithm. New search directions and proximity measures are defined based on a class of kernel functions, $\psi(t)=\frac{t^2-1}{2}-{\int}^t_1e{^{q(\frac{1}{\xi}-1)}d{\xi}$, $q\;{\geq}\;1$. If a strictly feasible starting point is available and the parameter $q\;=\;\log\;\(1+a{\sqrt{\frac{2{\tau}+2{\sqrt{2n{\tau}}+{\theta}n}}{1-{\theta}}\)$, where $a\;=\;1\;+\;\frac{1}{\sqrt{1+2{\kappa}}}$, then new large-update primal-dual interior point algorithms have $O((1\;+\;2{\kappa})\sqrt{n}log\;n\;log\;{\frac{n}{\varepsilon}})$ iteration complexity which is the best known result for this method. For small-update methods, we have $O((1\;+\;2{\kappa})q{\sqrt{qn}}log\;{\frac{n}{\varepsilon}})$ iteration complexity.

• Bulletin of the Korean Mathematical Society
• /
• v.52 no.4
• /
• pp.1047-1057
• /
• 2015

In [6], it is proved that the lengths of periods occurring in the ${\beta}$-expansion of a rational series r noted by $Per_{\beta}(r)$ depend only on the denominator of the reduced form of r for quadratic Pisot unit series. In this paper, we will show first that every rational r in the unit disk has strictly periodic ${\beta}$-expansion for Pisot or Salem unit basis under some condition. Second, for this basis, if $r=\frac{P}{Q}$ is written in reduced form with |P| < |Q|, we will generalize the curious property "$Per_{\beta}(\frac{P}{Q})=Per_{\beta}(\frac{1}{Q})$".

• Korean Journal of Child Studies
• /
• v.29 no.4
• /
• pp.231-248
• /
• 2008

This research used Q-Methodology to investigate kindergarten teachers' perception style regarding children's creativity. The 30 participants had various teaching experiences and educational backgrounds and were teaching in a variety of types of kindergartens in the cities of Busan and Ulsan. Individual teacher's subjective perspective was the main target for the analysis. Results showed four types of teachers' perceptions of creativity : 1) perceiving creativity as children's creative thinking ability, 2) focusing on creative curriculum development 3) perceiving creativity as children's creative personality, and 4) focusing on either teacher's thorough understanding of children's creativity or teachers' creativity. These results indicate that teachers tend to perceive creativity in narrow and specific domains. These findings are discussed with respect to their educational implications.

• Communications of the Korean Mathematical Society
• /
• v.30 no.4
• /
• pp.447-456
• /
• 2015

In this paper, we investigate the differential-difference equation $(f(z+c)-f(z))^2+P(z)^2(f^{(k)}(z))^2=Q(z)$, where P(z), Q(z) are nonzero polynomials. In addition, we also investigate Fermat type q-difference differential equations $f(qz)^2+(f^{(k)}(z))^2=1$ and $(f(qz)-f(z))^2+(f^{(k)}(z))^2=1$. If the above equations admit a transcendental entire solution of finite order, then we can obtain the precise expression of the solution.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.4
• /
• pp.98-108
• /
• 2015

This paper introduces the existence of purchase dependence that was identified during the analysis of inventory operations practice at a sales agency of dealing with spare parts for ship engines and generators. Purchase dependence is an important factor in designing an inventory replenishment policy. However, it has remained mostly unaddressed. Purchase dependence is different from demand dependence. Purchase dependence deals with the purchase behavior of customers, whereas demand dependence deals with the relationship between item-demands. In order to deal with purchase dependence in inventory operations practice, this paper proposes (Q, r) models with the consideration of purchase dependence. Through a computer simulation experiment, this paper compares performance of the proposed (Q, r) models to that of a (Q, r) model ignoring purchase dependence. The simulation experiment is conducted for two cases : a case of using a lost sale cost and a case of using a service level. For a case of using a lost sale cost, this paper calculates an order quantity, Q and a reorder point, r using the iterative procedure. However, for a case of using a service level, it is not an easy task to find Q and r. The complexity stems from the interactions among inventory replenishment policies for items. Thus, this paper considers the genetic algorithm (GA) as an optimization method. The simulation results demonstrates that the proposed (Q, r) models incur less inventory operations cost (satisfies better service levels) than a (Q, r) model ignoring purchase dependence. As a result, the simulation results supports that it is important to consider purchase dependence in the inventory operations practice.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.3
• /
• pp.245-253
• /
• 2000

The development and progression of oral cancer is associated with an accumulation of multiple genetic alterations through the multistep processes. Comparative genomic hybridization(CGH), newly developed cytogenetic and molecular biologic technique, has been widely accepted as a useful method to allow the detection of genetic imbalance in solid tumors and the screening for chromosome sites frequently affected by gains or losses in DNA copy number. The authors examined 19 primary oral squamous cell carcinomas using CGH to identify altered chromosome regions that might contain novel oncogenes and tumor suppressor genes. Interrelationship between these genetic aberrations detected and major oncogenes and tumor suppressor genes previously recognized in carcinogenesis of oral cancers was studied. 1. Changes in DNA copy number were detected in 14 of 19 oral cancers (78.9%, mean: 5.58, range: $3{\sim}13$). High level amplification was present in 4 cases at 9p23, $12p21.1{\sim}q13.1$, 3q and $8q24{\sim}24.3$. Fourteen cases(78.9%, mean: 3.00, range: $1{\sim}8$) showed gains of DNA copy number and 12 cases(70.5%, mean: 2.58, range: $1{\sim}9$) revealed losses of DNA copy number. 2. The most common gains were detected on 3q(52.6%), 5p(21.0%), 8q(21.0%), 9p(21.0%), and 11q(21.0%). The losses of DNA copy number were frequently occurred at 9p(36.8%), 17q(36.8%), 13q(26.3%), 4p(21.0%) and 9p(21.0%). 3. The minimal common regions of gains were repeatedly observed at $3q24{\sim}26.7$, $3q27{\sim}29$, $1q22{\sim}31$, $5p12{\sim}13.3$, $8q23{\sim}24$, and 11q13.1-13.3. The minimal common regions of losses were detected at $9q11{\sim}21.3$, 17p31, $13q22{\sim}34$, and 14p16. 4. In comparison of CGH results with tumor stages, the lower stage group showed more frequent gain at 3q, 5q, 9p, and 14q, whereas gains at 1q($1q22{\sim}31$) and 11q($11q13.1{\sim}13.3$) were mainly detected in higher stage group. The loss at $13q22{\sim}34$ was exclusively detected in higher stage. The results indicate that the most frequent genetic alterations in the development of oral cancers were gains at $3q24{\sim}26.3$, $1q22{\sim}31$, and $5p12{\sim}13.3$ and losses at $9q11{\sim}21.3$, 17p31, and 13q. It is suggested that genetic alterations manifested as gains at $3q24{\sim}26.3$, $3q27{\sim}29$, $5p12{\sim}13.3$ and 5p are associated with the early progression of oral cancer. Gains at $1q22{\sim}31$ and $11q13.1{\sim}13.3$ and loss at 13q22-34 could be involved in the late progression of oral cancers.

• Archives of Plastic Surgery
• /
• v.41 no.4
• /
• pp.344-349
• /
• 2014

Background An abnormally obtuse cranial base angle, also known as platybasia, is a common finding in patients with 22q11.2 deletion syndrome (22q11DS). Platybasia increases the depth of the velopharynx and is therefore postulated to contribute to velopharyngeal dysfunction. Our objective was to determine the clinical significance of platybasia in 22q11DS by exploring the relationship between cranial base angles and speech resonance. Methods In this retrospective chart review at a tertiary hospital, 24 children (age, 4.0-13.1 years) with 22q11.2DS underwent speech assessments and lateral cephalograms, which allowed for the measurement of the cranial base angles. Results One patient (4%) had hyponasal resonance, 8 (33%) had normal resonance, 10 (42%) had hypernasal resonance on vowels only, and 5 (21%) had hypernasal resonance on both vowels and consonants. The mean cranial base angle was $136.5^{\circ}$ (standard deviation, $5.3^{\circ}$; range, $122.3-144.8^{\circ}$). The Kruskal-Wallis test showed no significant relationship between the resonance ratings and cranial base angles (P=0.242). Cranial base angles and speech ratings were not correlated (Spearman correlation=0.321, P=0.126). The group with hypernasal resonance had a significantly more obtuse mean cranial base angle ($138^{\circ}$ vs. $134^{\circ}$, P=0.049) but did not have a greater prevalence of platybasia (73% vs. 56%, P=0.412). Conclusions In this retrospective chart review of patients with 22q11DS, cranial base angles were not correlated with speech resonance. The clinical significance of platybasia remains unknown.

• The Journal of the Korea Contents Association
• /
• v.19 no.12
• /
• pp.546-557
• /
• 2019

This study applied the Q methodology to customers using the Ethnick restaurant in Itaewon to understand subjective perceptions of customers using the restaurant. The purpose of the study is to characterize the subjective structure of the restaurant and to describe and analyze the characteristics of the types of subjective. As a result of type analysis, a total of five were derived. Type 1 (N=4) : Ethnic Food Preferred Type, Type 2 (N=5): Mainland flavour Seeking Type, Type 3 (N=3) : Food Material Sanitary Conditions Type 4 (N=6): The restaurant's Restaurant Service Preference Type, and Type 5 (N=2) : The mood sensibility type were analyzed to have various characteristics of each type. In future studies on Ethnick restaurants, we intend to modify and supplement the detailed Q methodological questions and analysis methods based on many literature and empirical studies to analyze the various opinions of the respondents in a specific and in-depth manner.

• Journal of the Korean Wood Science and Technology
• /
• v.15 no.2
• /
• pp.16-25
• /
• 1987

This study was carried out under controlled laboratory conditions in order to investigate the relative durability to decay of 6 Quercus species. The relative durability to decay was expressed by the percentage of weight loss by Lentinus edodes and Pleuratus ostreatus. The results obtained could be summarized as follows: 1. The most decay-resistant parts by L. edodes were heart wood of Q. sarrata TH. and sap wood of Q. aliena BL. and the least decay-resistant parts were heart wood of Q. acutissima C. and sap wood of Q. dentata TH.. 2. The most decay-resistant parts by P. osteratus were heart wood of Q. serrata TH. and sap wood of Q. aliena BL. and the least decay-resistant parts were heart wood of Q. variabilis BL. and sap wood of Q. dentata. TH.. 3. The percentage of weight loss in 6 Quercus species by section-height was not a consistent variation. 4. Putting these results together, Quercus aliena BL, could be regarded as the most decay-resistant by L. edodes and P. osteratus under normal condition among 6 Quercus species.

• Journal of the Korean Society of School Health
• /
• v.11 no.2
• /
• pp.243-270
• /
• 1998

This study was designed to find characteristics and patterns in Obese student's attitudes toward the school obesity program. Q-methodology was used as a research tool and the data were collected from October 1st, 1997 to April 30th, 1998. The results are as follows: 1. Q-sampling has been derived from the literature, and in-depth interviews of different groups (primarily students and normal weight students. Its credibility and validity were also tested by nursing and Q-methodology professors as well as school nurses. 34 statements were selected from a total of 197 statements collected. 2. In a P-sampling, 38 samples were selected. 3. Based on a 9 point scale, the selected respondents rated their operant definition of Obese student's attitudes toward school obesity programs. 4. The results of the above procedures were analyzed by a PCQ program. The results revealed that there are four attitudes toward the school obesity program. These four are the following: 1) First, demand for little exposure, which consisted of thirteen subjects. 2) Second, demand for other's support, which consisted of six subjects. 3) Third, demand for self-control, which consisted of four subjects. 4) Forth, demand for other's stimulation and motivation, which consisted of five subjects. In conclusion, this study discovers obese students have attitudes toward the school obesity program. By identifying the nature of each of the these types this study can be useful to manage and develop a school obesity program.