시각장애인의 인터넷 사용을 위한 보조시스템 개발

Erdal Erdal,Yucel Batu Salman,Hong?In Cheng(정홍인) 대한산업공학회 2013 대한산업공학회 추계학술대회논문집 Vol.2013 No.11

Prediction of concrete compressive strength using non-destructive test results

Hamit Erdal,Mürsel Erdal,Osman Şimşek,Halil İbrahim Erdal 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.4

Concrete which is a composite material is one of the most important construction materials. Compressive strength is a commonly used parameter for the assessment of concrete quality. Accurate prediction of concrete compressive strength is an important issue. In this study, we utilized an experimental procedure for the assessment of concrete quality. Firstly, the concrete mix was prepared according to C 20 type concrete, and slump of fresh concrete was about 20 cm. After the placement of fresh concrete to formworks, compaction was achieved using a vibrating screed. After 28 day period, a total of 100 core samples having 75 mm diameter were extracted. On the core samples pulse velocity determination tests and compressive strength tests were performed. Besides, Windsor probe penetration tests and Schmidt hammer tests were also performed. After setting up the data set, twelve artificial intelligence (AI) models compared for predicting the concrete compressive strength. These models can be divided into three categories (i) Functions (i.e., Linear Regression, Simple Linear Regression, Multilayer Perceptron, Support Vector Regression), (ii) Lazy-Learning Algorithms (i.e., IBk Linear NN Search, KStar, Locally Weighted Learning) (iii) Tree- Based Learning Algorithms (i.e., Decision Stump, Model Trees Regression, Random Forest, Random Tree, Reduced Error Pruning Tree). Four evaluation processes, four validation implements (i.e., 10-fold cross validation, 5-fold cross validation, 10% split sample validation & 20% split sample validation) are used to examine the performance of predictive models. This study shows that machine learning regression techniques are promising tools for predicting compressive strength of concrete.

Properties of Regular Set-connected Functions

Erdal Ekici 경북대학교 자연과학대학 수학과 2004 Kyungpook mathematical journal Vol.44 No.3

In 1999, Dontchev, Ganster and Reilly introduced the notion of regular set-connected functions. In this paper, properties of regular set-connected functions are investigated and obtained.

Analytical solution of a contact problem and comparison with the results from FEM

Erdal Öner,Murat Yaylacı,Ahmet Birinci 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.4

This paper presents a comparative study of analytical method and finite element method (FEM) for analysis of a continuous contact problem. The problem consists of two elastic layers loaded by means of a rigid circular punch and resting on semi-infinite plane. It is assumed that all surfaces are frictionless and only compressive normal tractions can be transmitted through the contact areas. Firstly, analytical solution of the problem is obtained by using theory of elasticity and integral transform techniques. Then, finite element model of the problem is constituted using ANSYS software and the two dimensional analysis of the problem is carried out. The contact stresses under rigid circular punch, the contact areas, normal stresses along the axis of symmetry are obtained for both solutions. The results show that contact stresses and the normal stresses obtained from finite element method (FEM) provide boundary conditions of the problem as well as analytical results. Also, the contact areas obtained from finite element method are very close to results obtained from analytical method; disagree by 0.03-1.61%. Finally, it can be said that there is a good agreement between two methods.

The Association between Subclinical Hypothyroidism and Epicardial Adipose Tissue Thickness

Erdal Belen,Aleks Degirmencioglu,Ertugrul Zencirci,Fatih Fahri Tipi,Özgür Altun,Gültekin Karakus,Ays¸en Helvacı,Aycan Esen Zencirci,Ezgi Kalaycıoglu 대한심장학회 2015 Korean Circulation Journal Vol.45 No.3

Background and Objectives: Subclinical hypothyroidism (SH) is considered to be a potential risk factor for cardiovascular disease. Epicardial adipose tissue (EAT) thickness is also closely related to cardiovascular disorders. The aim of this study was to evaluate whether SH is associated with higher EAT thickness. Subjects and Methods: Fifty-one consecutive patients with SH and 51 healthy control subjects were prospectively enrolled into this trial. Thyroid hormone levels, lipid parameters, body mass index, waist and neck circumference, and EAT thickness measured by echocardiography were recorded in all subjects. Results: Mean EAT thickness was increased in the SH group compared to the control group (6.7±1.4 mm vs. 4.7±1.2 mm, p<0.001). EAT thickness was shown to be correlated with thyroid stimulating hormone level (r=0.303, p=0.002). Multivariate logistic regression analysis revealed that EAT thickness was independently associated with SH {odds ratio (OR): 3.87, 95% confidence interval (CI): 1.92–7.78, p< 0.001; OR: 3.80, 95% CI: 2.18–6.62, p<0.001}. Conclusion: Epicardial adipose tissue thickness is increased in patients with SH compared to control subjects, and this increase in EAT thickness may be associated with the potential cardiovascular adverse effects of SH.

Zygomatic miniplates for skeletal anchorage in orthopedic correction of Class III malocclusion

Erdal Bozkaya,Alime Sema Yuksel,Suleyman Bozkaya 대한치과교정학회 2017 대한치과교정학회지 Vol.47 No.2

Objective: To evaluate the effects of facemask therapy, which was anchored from the zygomatic buttresses of the maxilla by using two miniplates, in skeletal Class III patients with maxillary deficiency. Methods: Eighteen skeletal Class III patients (10 girls and 8 boys; mean age, 11.4 ± 1.28 years) with maxillary deficiency were treated using miniplate-anchored facemasks, and their outcomes were compared with those of a Class III control group (9 girls and 9 boys; mean age, 10.6 ± 1.12 years). Two I-shaped miniplates were placed on the right and left zygomatic buttresses of the maxilla, and a facemask was applied with a 400 g force per side. Intragroup comparisons were made using the Wilcoxon test, and intergroup comparisons were made using the Mann-Whitney U-test (p < 0.05). Results: In the treatment group, the maxilla moved 3.3 mm forward, the mandible showed posterior rotation by 1.5°, and the lower incisors were retroclined after treatment. These results were significantly different from those in the control group (p < 0.05). No significant anterior rotation of the palatal plane was observed after treatment. Moreover, changes in the sagittal positions of the maxillary incisors and molars were similar between the treatment and control groups. Conclusions: Skeletally anchored facemask therapy is an effective method for correcting Class III malocclusions, which also minimizes the undesired dental side effects of conventional methods in the maxilla.

On Fuzzy Irresolute Functions

Erdal Ekici,Jin Han Park 한국지능시스템학회 2005 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.5 No.2

As a generalization of the notions of fuzzy α -irresolute, fuzzy preirresolute, fuzzy irresolute and fuzzy β -irresolute functions, we introduce the notion of fuzzy β α -continuous functions and investigate the relationships between fuzzy β α -continuous functions and fuzzy separation axioms.

Challenges and Some New Directions in Channel Coding

Erdal Arıkan,Najeeb ul Hassan,Michael Lentmaier,Guido Montorsi,Jossy Sayir 한국통신학회 2015 Journal of communications and networks Vol.17 No.4

Three areas of ongoing research in channel coding are surveyed, and recent developments are presented in each area: Spatially coupled low-density parity-check (LDPC) codes, nonbinary LDPC codes, and polar coding.

Comparison of effects of the tacrolimus and cyclosporine A on the colon anastomosis recovery of rats

Erdal Uysal,Mehmet Dokur 대한외과학회 2017 Annals of Surgical Treatment and Research(ASRT) Vol.92 No.6

Purpose: This study aims to examine and compare the effects of immunosuppressant cyclosporine A (CsA) and tacrolimus (TAC) on colon anastomosis recovery. Methods: Forty rats were randomly divided into 4 groups. The 4 groups were determined as follows: control group; sham group, given %0.09 NaCl; TAC group, given 0.5 mg/kg/day tacrolimus; and CsA group, given 5 mg/kg/day CsA. A 6-cm midabdomen incision was performed on the rats. An incision of all layers on the right colon was performed. Then anastomosis was undertaken. Laparotomy was performed on the seventh day postoperation. The colon bursting pressures were evaluated, histopathological examinations were undertaken, and E-cadherin expression and tissue hydroxyproline levels were evaluated. Results: Statistically significant differences were observed among bursting pressures of the groups (P < 0.001). The value was significantly low in TAC and CsA groups when compared to control and sham groups (P < 0.05). The tissue hydroxyproline levels were significantly low in TAC group compared to control group (P = 0.03). Fibroblast density and neovascularization were significantly greater in the control group compared to the TAC group (P < 0.05). Levels of collagen had decreased significantly in TAC group compared to other groups (P < 0.05). Conclusion: Our study showed that TAC may have a negative effect of colon anastomosis recovery. The lowest anastomosis bursting pressure was detected in TAC group. Also, collagen, hydroxyproline, fibroblast, neovascularization and E-Cadherin levels were comparatively lower in TAC group. CsA did not cause any significant changes to tissue hydroxyproline, collagen, fibroblast, and E-Cadherin levels.

On some types of continuous fuzzy multifunctions

Erdal Ekici 대한수학회 2004 대한수학회보 Vol.41 No.4

In this paper, by using operations, some characterizations andsome properties of fuzzy lower and upper continuous multifunctionsand its weaker and stronger forms including fuzzy lower and upperweakly continuous, fuzzy lower and upper theta -continuous,fuzzy lower and upper strongly theta -continuous, fuzzy lowerand upper almost strongly theta -continuous, fuzzy lower andupper weakly theta -continuous, fuzzy lower and upper almostcontinuous, fuzzy lower and upper super continuous, fuzzy lowerand upper delta -continuous, are presented.