A COMBINATORIAL APPROACH TO ASYMPTOTIC BEHAVIOR OF KIRILLOV MODEL FOR GL₂

Danisman, Yusuf Korean Mathematical Society 2019 대한수학회논문집 Vol.34 No.4

We find the asymptotic behavior of Kirillov model for irreducible induced representations of $GL_2$ by using combinatorial methods.

ON SUBFIELDS OF GK AND GENERALIZED GK FUNCTION FIELDS

Danisman, Yusuf,Ozdemir, Mehmet Korean Mathematical Society 2015 대한수학회지 Vol.52 No.2

In this article, we show that many of the genera that Giulietti and Fanali obtained from subfields of the GK curve can be obtained by using similar techniques used by Garcia, Stichtenoth and Xing. In the meantime, we obtain some new genera from the subfields of GK and generalized GK function fields.

ON SUBFIELDS OF GK AND GENERALIZED GK FUNCTION FIELDS

Yusuf Danisman,Mehmet Ozdemir 대한수학회 2015 대한수학회지 Vol.52 No.2

In this article, we show that many of the genera that Giulietti and Fanali obtained from subfields of the GK curve can be obtained by using similar techniques used by Garcia, Stichtenoth and Xing. In the meantime, we obtain some new genera from the subfields of GK and generalized GK function fields.

The effect of alumina and aluminium nitride coating by reactive magnetron sputtering on the resin bond strength to zirconia core

sengul Danisman,Soner Savas,Ozgur Ozturk,Seniha Baba,safak Kulunk,Tolga Kulunk 대한치과보철학회 2013 The Journal of Advanced Prosthodontics Vol.5 No.4

PURPOSE Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 µm aluminum oxide particles (Al2O3), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 µm Al2O3 + Al coating and air particle abrasion with 50 µm Al2O3 + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (α=.05). RESULTS The highest bond strengths were obtained by air abrasion with 50 µm Al2O3, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.

Change of attitude toward culture: pre- and post- expatriation experiences of managers

Sumeyra Alpaslan Danisman 한국사회과학협의회 2014 Korean Social Science Journal Vol.41 No.2

Cultural adjustment and intercultural effectiveness strongly influence interna-tional managerial issues, such as organizational success in a local firm, assignment com-pletion, cost of expatriation, and repatriation. Therefore, employees assigned to work inanother country need to prepare by learning about that country’s culture before expatria-tion. Much research has been conducted in the last few decades on the role of culture inexpatriation. This study examines how the attitude of expatriate managers toward theimportance of culture changes between the pre- and post-expatriation periods. This study isstructured as a two-step investigation: (1) pre-expatriation cultural preparation and (2)thoughts on the importance of culture after expatriation. The research sample was SouthKorean expatriate managers working in Turkey or the US. All participants were reached bythe trace method, and the interview data were analyzed in QSR NVivo software withcontent analysis. The results showed that expatriate managers’ attitude toward theimportance of culture changed as a result of expatriation. Pre-expatriation, some partici-pants did not prepare for the new culture. However, after the expatriation experience, allagreed that an understanding of the host culture was important during the assignment. Anoverseas experience allowed participants to understand the significant role played byculture in their adjustment to the new environment.

Anti-slamming bulbous bow and tunnel stern applications on a novel Deep-V catamaran for improved performance

Atlar, Mehmet,Seo, Kwangcheol,Sampson, Roderick,Danisman, Devrim Bulent The Society of Naval Architects of Korea 2013 International Journal of Naval Architecture and Oc Vol.5 No.2

While displacement type Deep-V mono hulls have superior seakeeping behaviour at speed, catamarans typically have modest behaviour in rough seas. It is therefore a logical progression to combine the superior seakeeping performance of a displacement type Deep-V mono-hull with the high-speed benefits of a catamaran to take the advantages of both hull forms. The displacement Deep-V catamaran concept was developed in Newcastle University and Newcastle University's own multi-purpose research vessel, which was launched in 2011, pushed the design envelope still further with the successful adoption of a novel anti-slamming bulbous bow and tunnel stern for improved efficiency. This paper presents the hullform development of this unique vessel to understand the contribution of the novel bow and stern features on the performance of the Deep-V catamaran. The study is also a further validation of the hull resistance by using advanced numerical analysis methods in conjunction with the model test. An assessment of the numerical predictions of the hull resistance is also made against physical model test results and shows a good agreement between them.

Anti-slamming bulbous bow and tunnel stern applications on a novel Deep-V catamaran for improved performance

Mehmet Atlar,성광철,Roderick Sampson,Devrim Bulent Danisman 대한조선학회 2013 International Journal of Naval Architecture and Oc Vol.5 No.2

While displacement type Deep-V mono hulls have superior seakeeping behaviour at speed, catamarans typically have modest behaviour in rough seas. It is therefore a logical progression to combine the superior seakeeping performance of a displacement type Deep-V mono-hull with the high-speed benefits of a catamaran to take the advantages of both hull forms. The displacement Deep-V catamaran concept was developed in Newcastle University and Newcastle University’s own multi-purpose research vessel, which was launched in 2011, pushed the design envelope still further with the successful adoption of a novel anti-slamming bulbous bow and tunnel stern for improved efficiency. This paper presents the hullform development of this unique vessel to understand the contribution of the novel bow and stern features on the performance of the Deep-V catamaran. The study is also a further validation of the hull resistance by using advanced numerical analysis methods in conjunction with the model test. An assessment of the numerical predictions of the hull resistance is also made against physical model test results and shows a good agreement between them.

Role of a Risk of Malignancy Index in Clinical Approaches to Adnexal Masses

Simsek, Hakki Sencer,Tokmak, Aytekin,Ozgu, Emre,Doganay, Melike,Danisman, Nuri,Erkaya, Salim,Gungor, Tayfun Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Objective: The aim of this study was to evaluate predictive role of risk of malignancy index in discriminating between benign and malignant adnexal masses preoperatively. Methods: This retrospective study was conducted with a total of 569 patients with adnexal masses/ovarian cysts managed surgically at our clinic between January 2006 and January 2012. Obtained data from patient files were age, gravidity, parity, menopause status, ultrasound findings and CA125 levels. For all patients ultrasound scans were performed. For the assessment of risk of malignancy index (RMI) Jacobs' model was used. Histopathologic results of all patients were recorded postoperatively. Malignancy status of the surgically removed adnexal mass was the gold standard. Results: Of the total masses, 245 (43.1%) were malignant, 316 (55.5%) were benign and 8 (1.4%) were borderline. The mean age of benign cases was lower than malign cases ($35.2{\pm}10.9$ versus $50.8{\pm}13.4$, p<0.001). Four hundred and five of them (71.2%) were in premenopausal period. Malignant tumors were more frequent in postmenopausal women (81% versus 29%, p<0.001). All ultrasound parameters of RMI were statistically significantly favorable for malignant masses. In our study ROC curve analysis for RMI provided maximum Youden index at level of 163.85. When we based on cutoff level for RMI as 163.85 sensitivity, specificity, PPV, NPV was calculated 74.7%, 96.2%, 94% and 82.6%, respectively. Conclusions: RMI was found to be a significant marker in preoperative evaluation and management of patients with an adnexal mass, and was useful for referring patients to tertiary care centers. Although utilization of RMI provides increased diagnostic accuracy in preoperative evaluation of patient with an adnexal mass, new diagnostic tools with higher sensitivity and specificity are needed to discriminate ovarian cancer from benign masses.

The effect of alumina and aluminium nitride coating by reactive magnetron sputtering on the resin bond strength to zirconia core

Kulunk, Tolga,Kulunk, Safak,Baba, Seniha,Ozturk, Ozgur,Danisman, Sengul,Savas, Soner The Korean Academy of Prosthodonitics 2013 The Journal of Advanced Prosthodontics Vol.5 No.4

PURPOSE. Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS. Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 ${\mu}m$ aluminum oxide particles ($Al_2O_3$), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + Al coating and air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (${\alpha}$=.05). RESULTS. The highest bond strengths were obtained by air abrasion with 50 ${\mu}m$ $Al_2O_3$, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION. Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.