• Korean Journal of Mathematics
• /
• v.24 no.2
• /
• pp.297-305
• /
• 2016

In this paper, by using fixed point theorem, we obtain the stability of the following functional equations $$f(pr,qs)+g(ps,qr)={\theta}(p,q,r,s)f(p,q)h(r,s)\\f(pr,qs)+g(ps,qr)={\theta}(p,q,r,s)g(p,q)h(r,s)$$, where G is a commutative semigroup, ${\theta}:G^4{\rightarrow}{\mathbb{R}}_k$ a function and f, g, h are functionals on $G^2$.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.200.1-200
• /
• 2003

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2018.06a
• /
• pp.122-123
• /
• 2018

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2016.09a
• /
• pp.94-103
• /
• 2016

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2016.09a
• /
• pp.104-110
• /
• 2016

• The Korean Journal of Pain
• /
• v.21 no.1
• /
• pp.44-50
• /
• 2008

Background: The use of regional local anesthetics or opioids during laparoscopic cholecystectomy (LC), in combination with general anesthesia, has been investigated in several interventional studies. Methods: We studied a total of 240 (n = 60, each) patients who were undergoing LC, and they received local infiltration and intraperitoneal instillation with normal saline or 0.25% levobupivacaine 60 ml. Group R (S) received infiltration of normal saline 20 ml before incision and at the end of surgery and then 40 ml intraperitoneal instillation after removal of the gall bladder under remifentanil-based anesthesia. Group R (L) received 0.25% levobupivacaine instead of normal saline in the same method like group R (S). Group S (S) received the same method as group R (S) under sevoflurane based anesthesia in place of remifentanil. Group S (L) received 0.25% levobupivacaine instead of normal saline with the same method as group S (S). Pain was assessed on a visual analog scale at 1, 6, 12 and 24 hours after operation. Results: The pain intensity of Group R (L) was significantly lower than that of group R (S), and the the incisional pain of group S (L) was significantly lower than that of group S (S) in the first six hours. The time delay to first operative analgesics in group R (S) and group S (S) was significantly shorter than that of group R (L) and group S (L). Conclusions: Infiltration and instillation of levobupivacaine reduced the postoperative pain and remifentanil did not increase the pain severity and opioid requirement when performing the LC.

• Animal Systematics, Evolution and Diversity
• /
• v.37 no.3
• /
• pp.229-234
• /
• 2021

Scolelepis (Scolelepis) daphoinos is newly reported in Korean fauna. This species can be distinguished from its congeners by the following characteristics: the presence of reddish pigment patches on the posterior part of the prostomium, notopodial postchaetal lamellae that are partially fused to the branchiae, and the presence of only the bidentate hooded hooks. The morphological diagnosis and photographs of S. (S.) daphoinos are provided. The partial mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal DNA(16S rDNA), and the nuclear 18S ribosomal DNA (18S rDNA) sequences from Korean specimens of S. (S.) daphoinos were determined. Species identification was supported by a comparison of DNA barcode sequences of COI and 16S rDNA with morphological examination from the specimens of type locality, China.

• Bulletin of the Korean Mathematical Society
• /
• v.61 no.1
• /
• pp.83-92
• /
• 2024

Let R be a commutative ring with nonzero identity and M be an R-module. In this paper, we first introduce the concept of S-idempotent element of R. Then we give a relation between S-idempotents of R and clopen sets of S-Zariski topology. After that we define S-pure ideal which is a generalization of the notion of pure ideal. In fact, every pure ideal is S-pure but the converse may not be true. Afterwards, we show that there is a relation between S-pure ideals of R and closed sets of S-Zariski topology that are stable under generalization.

• Knowledge Management Research
• /
• v.24 no.2
• /
• pp.65-85
• /
• 2023

This paper investigates how TMT's cognitive traits affect R&D investment. Drawing on the attention-based view, we propose that TMT's future orientation and risk preference increase the level of R&D investment. As R&D activities have long-term goal of generating proprietary knowledge, it is important to understand how TMT's attention toward future and risk affect R&D investment. Also, we test the moderating effect of CEO duality on R&D investment. As the CEO plays a leadership role in the TMT, if the CEO's decision-making authority is highly concentrated, the impact of TMT on R&D may decrease. We measure CEO duality and CEO ownership stake as CEO characteristics. Based on a sample of 837 U.S. manufacturing firms, the results show that when TMT has a higher tolerance for risk and higher future orientation, R&D intensity increases. However, when CEO also serves as chairman of board and CEO has higher ownership, TMT's influence on R&D investment weakens. This implies that TMT and CEO has power dynamic that can change based on CEO power supporting status. Overall, it suggests that TMT's attention and CEO power are important factors to improve longer-term knowledge accumulation of firm.

• ALGAE
• /
• v.24 no.3
• /
• pp.129-138
• /
• 2009

DNA-based discrimination of species is a powerful way for morphologically otherwise similar species, like centric diatoms. Here, the author sequenced long-range nuclear ribosomal DNAs, spanning from the 18S to the D5 region of the 28S rDNA, of Stephanodiscus, particularly including a Korean isolate. By comparisons, high DNA similarities were detected from the rDNAs of nine Stephanodiscus (>99.4% in 18S rDNA, >98.0% in 28S rDNA). Their genetic distances, however, were significantly different (Kruskal-Wallis test, p < 0.01) compared to two related genera, namely Cyclotella and Discostella. In addition, genetic distances of 18S rDNAs were significantly different (Student’s t-test, p = 0.000) against those of the 28S rDNAs according to individual genera (Cyclotella, Discostella, and Stephanodiscus). Phylogenetic analyses showed that Stephanodiscus and Discostella showed a sister taxon relationship, and their clade was separated from a cluster of Cyclotella (1.00 PP, 100% BP). This suggests that Stephanodiscus has highly conserved sequences of both 18S and 28S rDNA; however, Stephanodiscus is well-separated from other freshwater centric diatoms, such as Cyclotella and Discostella, at the generic level.